We combine our MEMS synthesis and test capabilities into a synthesis-for-test environment. A microresonator design meeting a variety of specifications is synthesized. The susceptibility of this design is then measured using our MEMS contamination analyzer. The nature of each defective microresonator is determined and the deviation form nominal performance is correlated to the bounds and design constraints used in the synthesis process. Feedback from this analysis is formulated into additional design constraints for the synthesis tool with the object of minimizing the impact of spot contaminations. Re-synthesis of the same designs using these additional constraints indicates that a certain class of catastrophic and parametric faults can be reduced by 25 percent without sacrificing performance.

This paper describes an approach to fault simulation of MEMS using an analog Hardware Description Language (HDL). HDL languages facilitate the description of mixed-domain devices, providing powerful representation capabilities which are not limited to the use of the traditional equivalent electrical modes. This is exploited in this paper for fault simulation of MEMS, showing the advantages of using an HDL for this task. An electro-thermal converter is used as test vehicle, for which an equivalent electrical more is readily obtained. Typical defects and failure mechanisms which can affect these devices fabricated using CMOS-compatible bulk micromachining are shown. These defects are used for illustrating the fault simulation approach which appears to be more comprehensive and systematic than previous approaches.

Microsystem testing has to cope with many problems, resulting from inaccessibility, different technologies and non-electrical failure modes. Possible test techniques have been investigated to test a new advanced microsystem. The implementation form and application area highly contributes to the choices made.

Micromechanical sensors are routinely simulated using finite element software. Once a structure has ben proposed, various parameters are optimized using experience, intuition, and trial-and-error. However, using proven finite element modeling coupled with a genetic algorithm (GA), optimal designs can be 'evolved' using a hands-free approach on a workstation. Once a problem is defined, the sole task required of the designer is the specification of a mathematical objective function expressing the desired properties of the sensor; the sensor geometry that maximizes the given function is then synthesized by the algorithm. We have developed an optimization tool and have applied it to the design of tuning fork gyroscopes (TFG). In this paper, we demonstrate how a TFG was optimized using GA's. TFG suspension beam lengths were adjusted through the robust search technique, which is resistant to trapping in local maxima. Desired vibration mode order and mode frequency separations were governed by the objective function as specified by the designer. This multidimensional nonlinear optimization problem had a solution space of over eight million possible designs. Industry-standard mechanical computer-aided engineering tools were integrate along with a GA toolbox and a web-based control interface. Designs offering reduced vibration sensitivity and increased sensor dynamic range have been produced. A tenfold decrease in total sensor optimization time has been documented, resulting in reduced development time.

This paper deals with a method aimed to automatically determine the parameters of a sensor in order to reach the end user's functional specifications. This general method, based on a behavioral modeling of the sensor, and on analog simulations and optimizations, has been setup and validated for a capacitive pressure sensor. The tools used are standard Microelectronics IC CAD tools. Four different steps are necessary to reach an optimal set of parameters. Considering a new family of sensor, the first step defines the different types of analog simulations that will allow a good decoupling between the sensor parameters. Next, for every new sensor specification, a first set of simulations is used to get realistic initial values for the main parameters. Then a first optimization, is performed, considering worst-case technological conditions. This method has been validated using two realistic and different functional specifications; the optimization results are in good agreement with the previously manufactured devices.

We present simulations of the dynamic and temperature dependent behavior of Micro-Electro-Mechanical Systems (MEMS) by utilizing recently developed parallel codes which enable a coupling of length scales. The novel techniques used in this simulation accurately model the behavior of the mechanical components of MEMS down to the atomic scale. We study the vibrational behavior of one class of MEMS devices: micron-scale resonators made of silicon and quartz. The algorithmic and computational avenue applied here represents a significant departure from the usual finite element approach based on continuum elastic theory. The approach is to use an atomistic simulation in regions of significantly anharmonic forces and large surface area to volume ratios or where internal friction due to defects using finite elements for efficiency. Thus, in central regions of the device, the motion of millions of individual atoms is simulated, while the relatively large peripheral regions are modeled with finite elements. The two techniques run concurrently and mesh seamlessly, passing information back and forth. We present novel simulations of the vibrational behavior of micro-scale silicon and quartz oscillators. Our result are contrasted with the predictions of continuum elastic theory as a function of size, and the failure of the continuum techniques is clear in the limit of small sizes. We also extract the Q value for the resonators and study the corresponding dissipative processes.

MEMS package requirements are by their nature application specific. MEMS devices are often inherently sensitive to stress induced by their packages sand often need direct access to the environment. Therefore, understanding the influence of packaging on MEMS is critical to a successful coupled package-device co-design. Here, an automated package-device interaction simulator has been developed. The simulator uses Finite Element Method models for both the package and the device analysis and ties the result of the simulations together through parametric models. This so- called Compact Model Extraction is an efficient way to solve complex problems. Several examples illustrate the use of this technique.

The important practical and realistic design issues of an electrostatic actuator/positioner with full-gap travel are discussed. Analytic expressions and numerical simulations show that parasitic capacitances, and non-uniform deformation in two and three dimensions influence the range of travel of an electrostatic positioner stabilized by the addition of a series capacitor. The effects of residual charge on electrostatically-actuated devices are described. The dynamic stepping characteristics of the positioner under compressible squeeze-film damping and resistive damping are compared. The physical descriptions of devices being fabricated in the MUMPs process are presented along with 3D simulation results that demonstrate viability.

A cantilever beam use din an Atomic Force Microscope is optimized with respect to performance. The first goal of the optimization is to maximize the first eigen frequency, the second goal is to maximize tip angle of the probe in either the static deflection mode or the first eigenmode. During the optimization we will constrain the stiffness of the probe to be constant. In the optimization, the angel is used as the objective but the maximization of the angel will also results in increased first eigen-frequency. Adding a restriction on the second eigen frequency, result in a significant change of the shape. The beam is modeled with 12 DOF beam finite elements and the optimizations are carried out with MMA.

The need for general modeling and analysis tools for MEMS devices has been well established, and several software packages designed to address these needs have appeared in the last five years. While being powerful and comprehensive, existing tools often require specialized knowledge of the methods involved in the analysis, and lack integration into a complete design environment. This paper describes a new MEMS design and analysis tool that uses a correct-by- construction approach in a tightly integrated environment of layout, 3D modeling, analysis, and system design. The MEMS design tool suite is integrated into an existing integrated circuit design package. Our goal is to automate as many steps of the process as possible, thus lowering the barrier to MEMS design.

Biological MEMS devices are being developed for applications in collection, monitoring, diagnostics and drug delivery. The objective of this work is to develop a simulation tool for the design, analysis and optimization of these devices. Simulations of biological MEMS devices are challenging due to the non-Newtonian behavior of biological fluids, coupling of flow with electric fields in electrophoretic separations, transport of non-homogeneous cellular structures and mixing between Newtonian and non-Newtonian fluids. This paper presents Computational Fluid Dynamic (CFD) simulations of biological fluid flow, mixing, electro-kinetics and transport of particles in microfluidic systems. A commercial CFD code, CFD-ACE+, that solves the full Navier-Stokes equations using a finite-volume approach has been adapted to perform these simulations of biological MEMS devices. Model predictions are validated through comparisons with experimental data.

This paper presents a fully integrated solution for the development of Micro Electro Mechanical Systems which covers component libraries, design tools and designs methodologies which are used in conjunction with conventional design automation tools. This solutio enables system houses in wireless and optical communications and consumers electronics markets to reduce their internal development costs and significantly accelerate their product development cycles.

Development of MEMS/MOEMS products is currently hampered by the need for design aids, which can assist in integration of all domains of the design. The cross-disciplinary character of MST requires a top-down approach to system design which, in turn, requires designers from many areas to work together in order to understand the effects of one sub-system on another. This paper describes current research on a methodology and tool-set which directly supports such an integrated design process.

Many MEMS devices which are thermally and/or electrostatically actuated contain moveable components which may undergo contact. The behavior is further complicated when hysteresis is exhibited after contact. Generally, MEMS devices consist of multiple materials with different mechanical and electrical properties. These factors pose a challenge for modeling highly non-linear MEMS behavior. This paper present an improved approach to modeling contact and hysteresis between any two bodies in a MEMS device. In particular, the three assumptions are relaxed. First, previous methods for modeling contact were able to model only a single dielectric layer. The new approach is capable of modeling multi-dielectric layers. Second, previous modeling methods required the specification of contact faces. This restriction has been generalized to specifying contact entities. Third, previously, modeling methods required an air stop gap assumption above a conductor to avoid numerical difficulties in electrostatic calculations. The new approach developed removes the air stop gap assumption. More realistic mechanical contact is simulated. Electrostatic and thermal driven actuation is considered. A number of case examples is presented to demonstrate the utility of the new contact and hysteresis approach. First a suspended test-beam structure is analyzed under different sets of boundary constraints and loading. Then, contact of an electrostatically actuated deformable mirror is analyzed.

The signal formation in piezoresistive silicon pressure sensors has been studied for many years and is very well understood meanwhile. Nevertheless, there are higher order effects of non-ideal behavior such as nonlinearities and hysteresis effects which limit the possible accuracy of such sensors considerably. In high volume applications like in automotive area it is worth to think about minimization of such effects in order to improve performance and also to enhance yield and to reduce costs. In this paper we report on a method to describe the above mentioned higher order effects of non-ideal behavior directly in terms of process- dependent parameters and therefore on a method to correlate process tolerances directly to output non-idealities and yield. The method comprises a quantitative value for 'design-capability' which we call 'influence strength' and which describes the quality of a design with respect to the accuracy-specification of the device as well as with respect to process tolerances. The effectiveness of the method is shown by several examples: first we use the method by applying it to effects of non-linearity. Second we present a simple model to describe the thermal hysteresis of integrated bulk-micromachined pressure sensors and we deduce a method to compensate and minimize hysteresis of integrated bulk-micromachined pressure sensor and we deduce a method to compensate and minimize hysteresis effects. Above all we show that it is possible to improve the accuracy of pressure sensors considerably and we compare our model predictions to experimental data.

The concept and the operation of micromachined monolithic 2D Microscanner are reported. Quartz material is used for its bulk micromachining capability as well as for its piezoelectric properties. Due to direct and reverse piezoelectric effect, the used design allowed to integrate both actuators and displacement sensor. A finite element calculation was performed to predict the operation principle of the microscanner. It consists of a movable table supported by four meander-line springs. On each spring metallic electrodes are deposited to induce strain allowing to move the table. The displacement measurement can be performed by electrical charges measurement on opposite spring. Preliminary results show the static and dynamic displacement capability. In static mode, a displacement of few microns can be obtained under a 150 V DC driving voltage. At resonance frequency, the vibration amplitude can reach 150 micrometers in X direction and 50 micrometers in Y direction. In comparison to conventional tube scanners, the advantages of micromachined monolithic microscanner, are low cost fabrication, large displacement range and close loop capability.

A micromechanically tunable Fabry Perot filter where the optical wavelength is tuned by moving a slider in the cavity is designed: the Fabry Perot filter is an air cavity in which the optical path ca be increased by inserting a transparent slider; the tuning effect depends on the thickness of the slider. Using a methodology based on a parametric investigation of the technological parameters, the design of a filter is proposed: a lower sensitivity to the position of the slider in the cavity is expected to realize the device using silicon micromachining.

Wireless transmission of data and energy is needed e.g. in medical applications and autonomous sensor systems, where the maximum size or the use of batteries are limited by system specific restrictions. A possible solution for frequencies up to 20 Mhz is the use of a transformer which consists of an air-cored and two rectangular microcoils. For simulation and optimization of the system an accurate model of the micro coil is needed to predict the terminal impedance. The model must map the geometrical and material specific parameters into the terminal impedance to avoid the use of correction factors and to obtain a wide range of validity. An accurate model is presented and verified by measurements made with realized micro coils. The model is implemented into the system simulator SABER along with other components of a sensor system. An optimization was carried out to gain optimal coil parameters. The optimization strategy is presented and the optimization was carried out to gain optimal coil parameters. The optimization strategy is presented and the optimization results agree very well with measurements made with a realized sensor system.

The basic evaporating two-phase flow mechanism in micro- channels is introduced. This flow is accompanied by a very high heat transfer coefficient and can remove very high heat fluxes at low temperatures, thus, making it attractive for micro device cooling applications. An experimental micro- channels chip was fabricate by means of a photolithography process, in order to study the flow mechanism involved in such flow. The results show that there is periodic behavior in evaporating two-phase flow in micro-channels, with a few harmonics.

The use of MEMS technology has enabled the fabrication of micro-optical and micro-electro-mechanical systems on a common substrate. This has led to new challenges in computer aided design of optical micro-electro-mechanical systems. We have extended our opto-electronic system DAD tool, Chatoyant, to attempt to meet the needs to optical MEMS designers. This paper present new component models and analysis techniques which extend our tool to support optical MEMS design. We demonstrate these extensions with the analysis of a micro-optical high speed FT engine and a 1 by 2 optical MEM interferometer switch.

Typical complex systems that involve microsensors and microactuators exhibit heterogeneity both at the implementation level and the problem level. For example, a system can be modeled using discrete events for digital circuits and SPICE-like analog descriptions for sensors. This heterogeneity exist not only in different implementation domains, but also at different level of abstraction. This naturally leads to a heterogeneous approach to system design that uses domain-specific models of computation (MoC) at various levels of abstractions to define a system, and leverages multiple CAD tools to do simulation, verification and synthesis. As the size and scope of the system increase, the integration becomes too difficult and unmanageable if different tools are coordinated using simple scripts. In addition, for MEMS devices and mixed-signal circuits, it is essential to integrate tools with different MoC to simulate the whole system. Ptolemy II, a heterogeneous system-level design tool, supports the interaction among different MoCs. This paper discusses heterogeneous CAD tool interoperability in the Ptolemy II framework. The key is to understand the semantic interface and classify the tools by their MoC and their level of abstraction. Interfaces are designed for each domain so that the external tools can be easily wrapped. Then the interoperability of the tools becomes the interoperability of the semantics. Ptolemy II can act as the standard interface among different tools to achieve the overall design modeling. A micro-accelerometer with digital feedback is studied as an example.

MEMS design tools are increasingly important as micro systems find wider applications. Though established structured design methodologies are in place for VLSI design, these tools cannot be applied to MEMS design without adaptation. Several needs must be met to enable MEMS design: (1) non-linear, dynamic and multi-energy domain design and simulation; (2) expression of complex and curvilinear geometries; (3) arbitrary orientation and placement of MEMS components; and (4) comprehensive, 3D visualization and analyses.

Modern microsystems use integrated sensors, controllers and actuators, and involve multi-physics phenomena. Detailed and accurate multi-physics based simulations are a key to device optimization and successful designs. In recent years, CFD- ACE+, a fluid flow solver has been validated and demonstrated on different MEMS devices involving coupled fluid flow, heat transfer, structural mechanics and electrostatics. Presented here are results of dynamic devices such as micropumps with dynamic valves and membrane micropumps as well as priming of a capillary pump and novel valves that use fluid surface tension for operation. Comparisons with experimental and other data are also presented to demonstrate the accuracy of multi-physics simulations. The capabilities of this state-of-the-art software and its usefulness in MEMS design environment is demonstrated.

The recently reported 2D successive network reduction (SUNRED) algorithm has been extended to solve thermal or electro-static fields in 3D. The paper presented the models and the solution algorithm of the 3D version and discusses in details the efficiency of the new 3D-field solver. Comparisons with other solvers demonstrate the superior features of SUNRED. The tool extensively supports the compact thermal model generation of the analyzed structure. A novel type of analysis, the time constant analysis is introduced in the paper.

Since the early 70s when microsystem technology was first introduce an enormous market for MST-products has been developed. Airbag sensors, micro pumps, ink jet nozzles etc. and the market is just about to start up. Establishing these products for a reasonable price requires mass production. Meanwhile, also computer-based design-tools have been developed in order to reduce the expenses for MST-design. In contrast to other physical design processes like e.g. in micro electronics, MEMS physical design is characterized by the fact that each product requires a tailored sequence of fabrication steps, usually selected from a variety of processing alternatives. The selection from these alternatives is based on economical constraints. Therefore, the design has a strong influence on the money and time spent to take an MST-product to market.

CMP has been providing infrastructures for integrated circuits manufacturing since 1981. These infrastructures have been extended to provide services for MEMS manufacturing. These services are available to Universities and Companies.

MEMS that exhibit strong coupling between electronics and mechanics need to be described and simulated in a united simulation environment, in order to achieve more flexibility from the description point of view, and to avoid convergence problems. Behavioral simulators and analogue hardware description languages enable modeling of MEMS. Even space- continuous mechanical problems can be described in the hardware description language. That description should and can be automated. Space-discretization commonly leads to very large system of equations. For solving such systems, mechanical FEM simulators usually exploit iterative algorithms that have very low memory demands. However, if the problem at hand contains electronics, as in the case of intelligent materials, iterative methods might be not applicable, since the convergence is not guaranteed anymore. In our behavioral simulator we have implemented a frontal solver, enabling solution of very large sparse matrices with modest main memory resources by storing only part of the matrix at the time. Thermal problems with more than 20000 nodes have been simulated.

The micro electromechanical systems (MEMS) industry in Europe is characterized by small and medium sized enterprises specialized on products to solve problems in specific domains like medicine, automotive sensor technology, etc. In this field of business the technology driven design approach known from micro electronics is not appropriate. Instead each design problem aims at its own, specific technology to be used for the solution. The variety of technologies at hand, like Si-surface, Si-bulk, LIGA, laser, precision engineering requires a huge set of different design tools to be available. No single SME can afford to hold licenses for all these tools. This calls for a new and flexible way of designing, implementing and distributing design software. The Internet provides a flexible manner of offering software access along with methodologies of flexible licensing e.g. on a pay-per-use basis. New communication technologies like ADSL, TV cable of satellites as carriers promise to offer a bandwidth sufficient even for interactive tools with graphical interfaces in the near future. INTERLIDO is an experimental tool suite for process specification and layout verification for lithography based MEMS technologies to be accessed via the Internet. The first version provides a Java implementation even including a graphical editor for process specification. Currently, a new version is brought into operation that is based on JavaBeans component technology. JavaBeans offers the possibility to realize independent interactive design assistants, like a design rule checking assistants, a process consistency checking assistants, a technology definition assistants, a graphical editor assistants, etc. that may reside distributed over the Internet, communicating via Internet protocols. Each potential user thus is able to configure his own dedicated version of a design tool set dedicated to the requirements of the current problem to be solved.

Computer aided design (CAD) systems are a key to designing and manufacturing MEMS with higher performance/reliability, reduced costs, shorter prototyping cycles and improved time- to-market. One such system is CFD-ACE+MEMS, a modeling and simulation environment for MEMS which includes grid generation, data visualization, graphical problem setup, and coupled fluidic, thermal, mechanical, electrostatic, and magnetic physical models. The fluid model is a 3D multi- block, structured/unstructured/hybrid, pressure-based, implicit Navier-Stokes code with capabilities for multi- component diffusion, multi-species transport, multi-step gas phase chemical reactions, surface reactions, and multi-media conjugate heat transfer. The thermal model solves the total enthalpy from of the energy equation. The energy equation includes unsteady, convective, conductive, species energy, viscous dissipation, work, and radiation terms. The electrostatic model solves Poisson's equation. Both the finite volume method and the boundary element method (BEM) are available for solving Poisson's equation. The BEM method is useful for unbounded problems. The magnetic model solves for the vector magnetic potential from Maxwell's equations including eddy currents but neglecting displacement currents. The mechanical model is a finite element stress/deformation solver which has been coupled to the flow, heat, electrostatic, and magnetic calculations to study flow, thermal electrostatically, and magnetically included deformations of structures. The mechanical or structural model can accommodate elastic and plastic materials, can handle large non-linear displacements, and can model isotropic and anisotropic materials. The thermal- mechanical coupling involves the solution of the steady state Navier equation with thermoelastic deformation. The electrostatic-mechanical coupling is a calculation of the pressure force due to surface charge on the mechanical structure. Results of CFD-ACE+MEMS modeling of MEMS such as cantilever beams, accelerometers, and comb drives are discussed.

Using CAD-CAM software tools in a production chain from the design to the NC code generation and manufacturing of workpieces is state of the art in common technologies such as milling or turning. Today these software tools are equipped with intelligent algorithms consider the characteristics of the respective production technology like e.g. the consideration of different tools to manufacture different volume sizes or the quality of special surface finishes.

We have recently reported two novel integrated optical detectors called BDJ detector and BTJ detector. The BDJ detector elaborated in CMOS process can be applied for wavelength detection while the BTJ detector based on a bipolar structure finds its applications in colorimetry. In order to use electronic CAD tools for designing micro- systems we have developed SPICE models for these detectors. The device modeling with physical approach has allowed us to determine photocurrents, which are functions of physical, geometrical, electrical, technological parameters. We have also defined schematic diagram and small signal models and integrated them in the HSPICE program. Simulations and measurements have validated these models.

The integrated BDJ detector basically consists of two buried junctions for collection of photocarriers at different depths. It can operate not only as a photodetector, but also as a wavelength-sensitive detector, because the ratio of the deep junction photocurrent to the shallow junction photocurrent is wavelength-dependent. The BDJ detector can be implemented using a standard CMOS process. The optimum design for a particular application requires divers considerations, such as process parameters, detector sizing, on-chip interface electronics, temperature sensing and compensation, etc. In particular, some geometrical and electrical parameters have significant effects on the device behavior and performances, and detector size as well as on- chip circuitry should be properly defined to meet specifications. Also, temperature-dependence of characteristics may need to be compensated. Two examples concerning design of integrated BDJ detector for specific applications are shown. One is for detecting spectral changes of absorption, while the other is for building a self-calibrated microspectrophotometer.

A surface micromachined polysilicon membrane, compatible with IC technology, was technologically designed and mechanically and thermally simulated by 3D finite element 'COSMOS' program in order to investigate its capability to work as micro hot plates for gas sensing applications. The optimized lay-out of hot plate consists of a polysilicon membrane of area of 110 by 110 micrometers ² supported by four 'poly' suspended bridges and a central 'poly' pillar (MWCP). The air gap between membrane and substrate is equal to 1 micrometers . Within this paper, the simulation results are shown as a function of input power and surface area of the membrane. At room temperature the following results were obtained. The maximum normal stress has a value of 151.12 N/m² and is situated at a distance of 20 micrometers around the central pillar. Also, the maximum displacement has a value of 3.81 by 10^-4 micrometers and it is located at about half distance between the center of the membrane and its lateral edge. At an input power of 100 mW applied to the MWCP structure, the strain-stress spatial distributions have been qualitatively preserved with respect to RT situation but all the values increased by about 1300 times. The value of this normal stress for the MWCP structure is now about 196.45728 by 10³ N/m². For an input power of 100 mW, the maximum displacements of the membrane are located in the same place as in the RT case, and their values are lower than 0.1 micrometers .

Simple Matlab/Simulink model is presented allowing to simulate numerically the dynamics of surface coupled cantilever in wide frequency range. Contact interaction between surface and cantilever is estimated by nonlinear distance function. Simulations show that cantilever can retain the harmonic response to the sine excitation above its fundamental resonant frequency due to its small mass and spring constant and strong surface adhesion forces. The motion of the cantilever becomes chaotic at certain combinations of amplitude and frequency of excitation, as cantilever and surface lose contact. Frequency spectrum of cantilever deflection contains high frequency component corresponding to the nonlinear surface-cantilever contact spring and dependent on the surface material parameters.

This paper reports a lumped-parameter mathematical model for a magnetohydrodynamic (MHD) micropump being developed by the authors. The micropump can be used to deliver electrically conductive fluids. The major advantage of a MHD based micropump is that it does not contain any moving parts. It may have potential applications in medicine delivery, biological and biomedical studies. To develop a design guideline for the MHD micropump, it is desired that the dynamic behavior of the flow in a microsystem driven with MHD body force. A bond graph model has been developed for the MHD micropump. A commercial software, 20 SIM, was used as the simulation tools. The simulation results for two different sizes of micropumps with a 1 percent salt-water solution used as a pumping fluid are presented in the paper.

Two color-sensitive detectors, based respectively on BDJ and BTJ structures, have recently been developed in standard VLSI processes. The BDJ structure implemented in a CMOS process can produce two photocurrents, and the photocurrent ratio is a monotone function of the wavelength. The BTJ structure realized in a BiCMOS process gives three band-pass spectral response, thus allowing trichromatic color detection. In order to obtain better insight into the behavior of these two structures, and to simulate their characteristics, we have established physical models for photocurrent calculations. The following approach has been adopted: i) calculating drift and diffusion photocurrent components which are produced in different depletion layers and neutral regions of silicon; ii) according to their contributions, determining photocurrents flowing through each buried junction. A computer program can be written for device simulations. The validity of these models has been verified through comparison between simulations and measurements. These models can also be used to study effects of parameters involved in the presented models.

The work described in this paper is aimed at fault modeling and fault simulation of electrostatic comb-drives. At present, we have taken into account the most typical defects which we have encountered through fabrication of resonator test structures. These defects include stiction of the suspended beams to the substrate surface and the break of comb-drive model, and the impact of a faulty comb-drive is assessed for different resonator-based designs.

Spatial light modulators are the well known digital mirror devices (DMD), micromechanical switching arrays and arrays of micro Fabry-Perots. As a new design micro slit arrays are presented. A micromachining technology was developed for microfabrication. Slits with dimensions of 3 micrometers ...1 mm were prepared on a membrane with a thickness of 1 micrometers . The aspect ratio is excellent. Dimensions down to optical aberration corrected limitation of microdevices and nearly down to light wavelength can be realized. Designs are addressable micro slit arrays in two membrane technology and coded micro slit arrays in one and two membrane architecture with more than 100 elements. Their principles, the design and their optical performance are discussed. The future application of these spatial light modulator microdevices is the digital light processing. The performance for example of a microspectrometer with the micro slit array is the increase of spectral resolution up to the factor of 2.6 based on generation of additional subpixels and simultaneously the increase of signal to noise ratio up to the factor of 10 and the parallelization by more than 100 modulator elements or light sources and its multiplexing. The application of micro slit arrays for realization of the HADAMARD principle is presented.

A transformer equivalent circuit is used to represent a piezo-actuator. The circuit is developed starting from electromechanical transduction principles and included in SPICE software. The actuator is a length-expanded cantilever. Analytical and simulated results are compared and found in god agreement both in static and dynamic studies.

A novel vibration sensor in silicon technology for monitoring the tool state of a lathe was developed. The high acceleration amplitudes of up to 4000 g required a careful design of the piezoresistive vibration sensors, based on a silicon membrane, in order to achieve a maximum sensitivity in a wide frequency range. The Finite Element Method (FEM) program ANSYS as well as ICECREM, a simulation program for processing steps in semiconductor production, were used for the optimization of the sensor device shape and internal structure. By ICECREM simulations the process specifications for the piezoresistors and for the silicon membrane were determined. The FEM analyses showed that a proper design of the seismic mass and placement of the piezoresistors can reach a sensitivity of up to 30 (mu) V/Vg for vibration sensors operating in the above-mentioned acceleration range at a resonance frequency of 14 kHz in the undamped state. This is the highest sensitivity known for this working range. Given the geometrical deviations caused by the production in a CMOS-compatible process, test results correspond well with the simulation.

Computational design of MEMS involves several strongly coupled physical disciplines, including fluid mechanics, heat transfer, stress/deformation dynamics, electronics, electro/magneto statics, calorics, biochemistry and others. CFDRC is developing a new generation multi-disciplinary CAD systems for MEMS using high-fidelity field solvers on unstructured, solution-adaptive grids for a full range of disciplines. The software system, ACE + MEMS, includes all essential CAD tools; geometry/grid generation for multi- discipline, multi-equation solvers, GUI, tightly coupled configurable 3D field solvers for FVM, FEM and BEM and a 3D visualization/animation tool. The flow/heat transfer/calorics/chemistry equations are solved with unstructured adaptive FVM solver, stress/deformation are computed with a FEM STRESS solver and a FAST BEM solver is used to solve linear heat transfer, electro/magnetostatics and elastostatics equations on adaptive polygonal surface grids. Tight multidisciplinary coupling and automatic interoperability between the tools was achieved by designing a comprehensive database structure and APIs for complete model definition. The virtual model definition is implemented in data transfer facility, a publicly available tool described in this paper. The paper presents overall description of the software architecture and MEMS design flow in ACE + MEMS. It describes current status, ongoing effort and future plans for the software. The paper also discusses new concepts of mixed-level and mixed- dimensionality capability in which 1D microfluidic networks are simulated concurrently with 3D high-fidelity models of discrete components.

Common porous materials, some of which will be considered in the chapters of this book, include concrete, paper, ceramics, clays, porous semiconductors, chromotography materials, and natural materials like coral, bone, sponges, rocks and shells. Porous materials can also be reactive, such as in charcoal gasification, acid rock dissolution, catalyst deactivation and concrete. This study continues the investigations about the properties of, so-called, hollow glass. In this paper is presented a computer simulation approach in which the thermo-mechanical behavior of a 3D microstructure is directly computed. In this paper a computer modeling approach of porous glass is presented. One way to test the accuracy of the reconstructed microstructures is to computed their physical properties and compare to experimental measurement on equivalent systems. In this view, we imagine a new type of porous type of glass designed as buffer layer in multilayered printed boards in ICs. Our glass is a variable material with a variable pore size and surface area. The porosity could be tailored early from the deposition phases that permitting us to keep in a reasonable balance the dielectric constant and thermal conductivity.

The fabrication of microstructured workpieces with conventional manufacturing methods, such as turning, milling, shaping or drilling--imposes high demands on the machine behavior and the tool properties. The requirements in terms of machine characteristics are currently met by only few machine tools. An ultra precision milling machine which permits microstructures to be manufactured with optical quality has been designed and built at the IPT in Aachen. Using natural diamond cutting tools, a broad range of materials like, for example non-ferrous metals or plastics, can be machined, producing real 3D-structures with a surface roughness of below 5 nm Ra. Only the diamond can be sharped to the required level of accuracy. Cutting edge sharpness and rounded are crucial to the manufacturing quality of the work piece. Minimum structure sizes in the submicron range and aspect ratios of more than hundred have been achieved by diamond matching at the IPT. Even small series or prototypes can be manufactured flexible and cost- effectively when mechanical cutting techniques are applied. Parts can be mass-produced cheaply when reproduction techniques, such as galvanic forming, injection molding or stamping are applied.

Economic success of microsystems technology requires a wide range of materials as well as the related manufacturing processes. A suitable technology for medium/large scale production is micro injection molding which actually allows the manufacturing of plastic microstructures with 20 microns minimum thickness, structural details of approximately 0.2 microns or maximum aspect ratios of more than 20. These microstructures are, for example, applied as components in micro optics, micro fluidics or minimally invasive surgery. This is demonstrated by microparts that are currently available or will be available soon. For higher economic efficiency and cost reduction, fully electrical injection modeling machines of higher accuracy have been applied. Also, micro insert injection molding reduces mounting costs. Manufacturing of metal or ceramic microparts by powder injection modeling allows large-scale production of complex shaped microstructures with a wide range of materials. Typical examples are sintered structured like stepped LIGA- gear wheels with minimal dimensions of 50 microns in different metal and ceramic materials. Micro Precision Casting originating from conventional investment casting is a suitable process for small/medium-scale production. Examples are microturbine housings made of precious metal alloys. An approach similar to rapid prototyping applies photocurable reactive resins. Photoinduced molding of low viscous resins under ambient conditions leads to significantly reduced cycle times. Additionally, rapid testing of new composite materials can be performed easily. Microcomponents molded from polymers and different composites like dyes with nonlinear optical properties and nanosized ceramic powders will be presented.

The prediction of the dimensional resolution, depending on viscosity, shrinkage and crystallization of engineering plastics is essential for the production of molded microstructures. Conventional test structures like 'flow spirals' cannot be used in microscale molding due to insufficient stability. Hence, new micro test structures realized by means of the LIGA techniques were designed to investigate these effects. On the one hand stand-alone circle-shaped structures were produced to compare the filling of microstructures with different aspect ratios at one structure height. Therefore, the wall thickness is varied in steps from 2.5 micrometers to 20 micrometers . Furthermore 'wedge' structures with radius at the tips of 0.5 micrometers and 5 micrometers are arranged in circles at critical locations of the insert in order to investigate the influence of the flow path length and the orientation towards the direction of flow. All structures were mounted to a ground plate with a spacing of 500 micrometers to eliminate all influences among the structures. First results revealed different filling behavior for critical sections of the part. Even circle structures with 5 micrometers wall thickness can be filled and demolded. Wedge structures with sub-micron tip radii are observed and the filling of 5 micrometers radii can be achieved. Very small tips with less than one micro radii cannot be filled yet. The structure's position towards the direction of flow does not seem to play an important role on the filling behavior of those micro structures.

Micro fabrication techniques for thick structure are developed. One method is a micro fabrication method using injection molding. And another method is the coating method using hydro gel. First method is almost same technique which is named MIM or CIM. In the process, the powder is mixed with the binder and mixture is injection molded. the molded parts are extracted the binder using supercritical carbon dioxide, and sintered. Employing this process, micro pattern which has aspect ratio more than 5 can be molded by metal powder and PZT. In this method, a micro pattern made by laser ablation is used as a die. As compared with other micro fabrication techniques, this method can utilize the molding die repeatedly. Consequently, the producing cost of micro parts can be decreased by this method on actual production process. Second method is a technique which uses the PVA hydrogel. The powder is mixed with water which contains the PVA from 3 to 15 percent. The mixed compound is sandwiched with PE films.It is froze and a gel sheet which has thickness from 40 to 100 micrometers is obtained. Using the sheet, the ceramic and metal are coated on the Silicon wafer, and thick structure is fabricated.

Shape memory alloys are used in the manufacture of microactuators and stents. This paper discusses (1) the nature of the surface oxide layer on NiTi shape memory alloys; (2) its role in protecting the underlying base metal from chemical and electrochemical etchants; (3) how the oxide can be removed and;; (4) the necessity of rapid by- product removal from the metal-etchant interface to achieve even the etching of the underlying alloy.

We present here three technological processes developed by LETI which have resulted in successful industrial transfers for MEMS.

Minimizing mask absorber thickness is an important practical concern in producing very small features by the LIGA process. To assist in this minimization, we have developed coupled numerical models describing both the exposure and subsequent development of a thick PMMA resist. The exposure model addresses multi-wavelength, 1D x-ray transmission through multiple beam filters, through the mask substrate and absorber, and the subsequent attenuation and photon absorption in the PMMA target. The development model describes 1D dissolution of a feature and its sidewalls, taking into account the variation in absorbed dose through the PMMA thickness. These exposure and development models are coupled in a single interactive code, permitting the automated adjustment of mask absorber thickness to yield a prescribed sidewall taper or dissolution distance.We have used this tool to compute the minimum required absorber thickness for exposures performed at the ALS, SSRL and NSLS synchrotron sources. Results are presented as a function of the absorbed dose for a range of the prescribed sidewall tolerance, feature size, PMMA thickness, mask substrate thickness and the development temperature.

Today's dimensionality of microtechnology enables the fabrication of precise objects, like diffraction limited x- ray transmission optics. Based on deep x-ray/LIGA technology, first results are presented concerning the fabrication and modelling of parabolic and massive-serial focalizing x-ray transmission lenses in PMMA, as opposed to standard grazing incidence reflection optics. The theoretical performance limitations of such optical systems are derived and stem from fundamental physical properties like the anomalous dispersion properties of the used materials. Parabolic x-ray transmission lenses are limited to very small numerical apertures, but behave optically like any ideal transmission lens would do. The advantages of deep x-ray LIGA technology are its favorable surface roughness and inherent precision. Unlike silicon micromachining, LIGA technique profits from a larger choice of possible materials. The importance of low-Z compounds like Lithium or Be/B is pointed out, together with necessary new techniques in the framework of LIGA, like electroplating from organic solutions.

In the past, the capillaries of fiber-spinneret were made by drilling or by micro electro-discharge-machining. In this study a new process for manufacturing a spinneret die was developed. LIGA process provides the new method of capillary manufacturing. The diameter of the capillaries is 200 micrometers . and L/D ratio is 3. The stability during fiber spinning can be improved by using capillaries with higher aspect ratio. Details on micro-injection mold design, analysis, manufacturing and process conditions will be discussed. Better process conditions will be introduce through experiment design technology. Through single injection molding process, a 48-capillaries structure was formed. The diameter of each capillary was inspected along longitudinal direction carefully. The result shows that the accuracy of the diameter for each capillary can be controlled to be 200 +/- 1 micrometers range. Capillaries to spin w-shaped micro- fibers were also developed in this work. The width in each capillary is 100 micrometers with higher aspect ratio up to 16. With consequent treatments and electro-forming, the spinneret can be produced in the mass production way. A real metal spinneret die was electro-formed in this study. The technology developed here can also be used in the fabrication of MEMS components.

Many new applications in medicine, telecommunication, automation systems etc. require powerful microdrives. Speeds up to 100.000 rpm and output torques in the (mu) Nm-range are typical characteristics of electromagnetic micromotors with diameters of a few millimeters. To accomplish a powerful microdrive, these micromotors have to be combined with micro gearheads of the same outer diameter. For such a micro gearhead with toothed wheels manufactured by use of the LIGA process a multi-stage planetary gear has many advantages. Many stages with different gear ratios can be combined to achieve a great number of different transmission, but manufacturing tolerances and a clearance for assembly must be respected. Therefore besides the selection of a reliable gearhead type and a suitable manufacturing process the optimization of the tooth profile is the key to the implementation of powerful micro gear systems with high output torques and efficiencies. The involute profile is the most suitable toothing, but many calculations and simulations are required to find the right modulus, total depth of teeth, profile offset etc. In a joint project Dr. Fritz Faulhaber GmbH and Co. KG and the Institut fuer Mikrotechnik Mainz GmbH developed a powerful microdevice with an outer diameter of only 1.9 mm.

This paper gives a survey of the possibilities and limitations concerning precision laser machining of different materials used in microsystems. The presented investigations were performed using 193 nm and 248 nm excimer, frequency converted Nd:YAG and 780 nm Ti:Sapphire femtosecond laser radiation. Besides providing technologies for precise and micro laser machining, the examinations were focused on reducing machining time and costs. The importance of adapted processing techniques, including the use of flexible masks in combination with excimer lasers is presented. Depending on the target material and processing parameters, different machining techniques are discussed. Since one single laser type cannot serve to fulfill all requirements in cutting, material removal, drilling, surface structuring, or metallization, each application asks for a well-considered system choice, and a specific process optimization.

Excimer laser ablation is used in conjunction with mask projection techniques to produce novel and complex microstructures. Special multiple-mask techniques have been developed which, together with synchronized workpiece motion and laser firing, are used for the manufacture of features such as micro-channels, ramps, contoured surfaces with channels etc. These new techniques allow planar microstructures to be combined and superimposed onto curved or multifaceted shapes, thereby enabling hitherto unobtainable structures to be produced. Details are given of the techniques used along with examples of the types of structures which have been produced.

Laser stereolithography deals with the manufacture of 3D objects that are made by space-resolved laser-induced polymerization. In order to obtain 3D micro-objects, we developed a new microstereolithography apparatus based on the use of a dynamic mask generator which allows the manufacture of a complete layer by only one irradiation, the part being manufactured layer by layer. This process is compared of a broad-band visible light source, that leads to the elimination of speckle effects resulting from the conventional use of a laser beam, and of a liquid crystal display as the dynamic mask generator. A lateral resolution of 2 micrometers has been demonstrated, and some examples of high aspect ratio micro-objects are presented.

By means of micro structuring the size of a mass spectrometer can be scaled down to about a few cubic centimeters at high precision and reproducibility. Such a miniaturized mass spectrometer is a micro system of very complex nature. It comprises of at least three main parts to be manufactured by micro structuring: an electron source, an ionization region including accelerating and focusing units and a mass analyzer with detector. Since microsystem technologies are 2.5 dimensional - i.e. defined undercuts are difficult to realize - the spectrometer is built of three substrate-layers to achieve the necessary 3D structure. These layers represent the three above mentioned units - each composed of several metal and isolation layers. The substrates are placed cross wise with respect to their electrical connections, so that the top structure can be bonded from below and the bottom structure from the top. The presented layout and processing is adapted to the physical requirements of the system as there are e.g. pressure stages, low capacitance and uncritical assembly, the type of processes and their order are chosen compatible to each other and to the involved materials and structures. This concerns for example the selectivity of etching processes, compatibility of metals, thermal stress, mechanical stress during thick photoresist removal and the thickness of membranes and freestanding structures to survive the mechanical stress imposed during the fabrication.

In recent years, microfabrication techniques derived from existing expertise in the microelectronics industry have been applied to the fields of biotechnology and clinical diagnostics. In this work, 'Biofactory-on-a-chip' devices are being developed to demonstrate how these microfabrication techniques can be combined with electrokinetic phenomena to manipulate, separate and characterize biological material using non-uniform electric fields. Excimer laser ablation methods have been used to fabricate these devices. Key to the successful fabrication and functioning of 'Biofactory' devices is the ability to: machine microelectrodes with micrometer feature sizes over a large area; create via-holes in insulating layers to form electrical interconnects in multilayer structures; fabricate shaped microfluidic channels; and control alignment in the device production with micron accuracy.

Inductors are essential for fully integrated, complex RF circuits such as single chip radios. Both high Q, Q > 15, and high precision, +/- 2 percent, inductors are needed to meet phase noise specifications for on-chip VCO's and for reactive impedance matching to improve power transfer and linearity. We describe the design, test and simulation of self-assembled, micromachined inductors lifted away from the substrate by tensile stress in the metallization. The air gap reduces the capacitive coupling to the substrate, increasing both the Q and self-resonant frequency. For 2nH inductors we have measured Q-14 at 2GHz, with process variation < 2 percent. Increased temperature and current strongly increase the loss, but do not effect the inductance. The inductors are also relatively insensitive to mechanical excitation, with forces approximately 30g's required to significantly modulate the inductor loss under resonant excitation. Extensive EM simulations of this design methodology suggest that we should be able to reach Q > 25 at 2GHz and maintain 10GHz. We also compare these results with state of the art fully integrated Si RFIC planar inductors.

For many applications in rapid growing markets of microproducts, e.g. miniaturized hard disk drives in personal computers, mobile optical scanners, or for the market of consumer electronics, a novel, penny-shaped micromotor was developed at IMM. Designed to provide an output torque of more than 100 (mu) Nm, the permanent magnet motor shows a diameter of 12.8 mm and a height of 1.4mm. Besides the maximum torque and the ultra-flat shape, one further essential design parameter was a construction that allows an easy assembly and is suitable for mass-production. An important contribution to mass production philosophy is the intensive use of microfabrication technologies especially for both, the production of the permanent magnet rings by micro molding and micro compressing techniques and the micro coils by the way of photolithographic batch processes.

In this paper we propose a silicon UV flame detector for combustion systems. In gas burners the relative intensity of flame radiation is dominant in the UV region. In the visible and IR regions the relative intensity of radiation of the incandescent surfaces is several orders of magnitude greater than the gas flame radiation intensity. Therefore it is required that the flame detector has a much greater sensitivity in the UV region. The propose detector is formed on n-type silicon on isolator wafer. In order to suppress sensitivity in the visible and the IR regions, the absorption region of the detector is greatly reduced, and a UV filter utilizing photonic crystal is designed. The p-n junctions are formed by very shallow diffusion of impurities. The contacts are made after the deposition of a thin oxide layer. The UV filter is then sputtered on the detector surface. The filter consists of a thin silver film, and a 1D photonic crystal made of twelve pairs of NaF/Y₂O₃ layers. The photonic band gaps of the crystal should suppress the propagation of the light with wavelengths greater than 0.35 micrometers . For the detector active area of 5 mm², the thickness of the silver layer of 0.13 micrometers and a dark current of 1 nA, the noise equivalent power at 0.32 micrometers is 4.23 10^-13 W/Hz^1/2. The calculated flame signal to total signal ratio is 0.52.

We propose a single-chip multicolor photodetector for micrometers range based on a linear IR semiconductor detector array with an integrated 1D photonic bandgap (PBG) filter. A wedge- shaped defect slab is introduced into the filer instead of one of the layers. The bandgap of the photonic crystal coincides with the spectral sensitivity range of the photodetector array, while the built-in defect gives a transmission peak within the same range. The defect thickness varies along the array length and thus shifts the transmission peak wavelength. The optimized photonic bandgap filter including defect is designed using the transfer matrix method. The peak frequency is tuned by choosing the geometrical parameters of the wedge-shaped defect. In our experiments, thin alternating Si and SiO₂ films are sputtered onto the array surface, thus forming a 1D PBG structure. The defect is fabricated by gradually changing the middle Si layer thickness over the width of the array. Its wedge-forming is performed by micromachining or, alternatively, by in-situ oblique deposition within the sputtering system and, possibly, subsequent chemomechanical polishing. The characteristics of the finished PBG structure are measured using an IR spectrophotometer. An increase of the number of PBG layers improves the confinement of transmission peaks and thus decreases the crosstalk between the array elements. Although our multicolor detector is designed for the (3-5) micrometers atmospheric window, it can be straightforward redesigned for any other optical range.

InP-based microstructuring optimization is presented in order to develop the fabrication of highly selective and widely tunable optical filter for WDM applications. Technological constraints such as etching selectivity, etching anisotropy, sticking phenomena and residual stress are listed and their respective practical solutions are demonstrated. Opto-electro-mechanical simulations combined with this technological 'know how' have yielded to the fabrication of 8 air gaps InP-based microstructures suitable for production of optical filter demonstrators.

A sub-micron grating can be the key miniaturized planar element in Micro-opto-electromechanical systems where it performs a number of optical functions such as light routing, beam splitting, spectral-analysis, polarization filtering, beam recombination, spatial resonance excitation, in the domains of displacement measurement, biochemical sensors, environment monitoring, laser emission control, WDM communications, to quote a few current applications. This paper will describe the main stream technology of sub-micron gratings and illustrate its application potential.

As micro-opto-electro-mechanical systems and devices evolve from prototypes to products, the need for cost-effective mass production techniques becomes crucial. This challenging cost goal can be reached using mass replication techniques like injection molding and hot embossing.In order to meet the special demands of miniaturization these replication techniques have been modified incorporating variothermal process control, an evacuation of the mold chamber and a modification of the molding parameters including elevated temperatures. Based on these techniques numerous micro- optical systems have been developed including a twelve fold multi-fiber connectors with an average insertion loss of 0.35 dB, an optical bench using polymeric alignment structures on a silicon substrate, a 4 by 4 star coupler with passive fiber alignment, a 1 by 2 singlemode fiber switch, and a singlemode 4 by 4 optical matrix switch. In these systems geometrical tolerances of one micrometers and below have been obtained allowing passive alignment of multimode and singlemode fibers during the assembly process and high precision positioning of fibers during operation.

The microchip laser is the most compact and the simplest diode pumped solid state laser, with a typical dimension of 0.5 mm³. In spite of the extreme simplicity of this concept which was described in sixties, the first devices have been realized much later in eighties, in different laboratories in the world. The main advantage of the microchip laser is its ability to be fabricated with collective fabrication processes, using techniques such as currently used in microelectronics, allowing a low cost mass production with a good reproducibility and reliability. The microchip lasers are very simple to use without any optical alignment and any maintenance. They foretell a true technical revolution in the domain of solid state lasers which should be opened to high volume and low cost markets. They have many different industrial applications in large markets such as: automotive, laser marking and material processing, environmental and medical applications, public works, telecommunications, etc.

We give a quick overview of MOEMS technologies under development at LETI. We mainly focus on recent developments in relation with the 'Europractice Competence Center Number 3' dedicated to MOEMS whose LETI is the coordinator. MOEMS are optical devices offering simultaneously optical and mechanical functions, and achieved in a collective manner by means of microelectronics like process and machines. Different devices and demonstrators already exist at LETI such as micro-switches for optical fiber networks, vibration sensors, scanning devices for laser or are under development such as tunable Fabry-Perot interferometers. Examples and performances are presented.

Flip chip assembly technology offers a reliable and advanced packaging approach for hybrid integration of micromachined optical components. In this paper we present flip chip integration of microlens arrays with surface micromachined segmented deformable micromirrors. 12 by 12 electrostatic micromirror arrays were fabricated through a commercial surface micromachining process and integrated with glass microlenses. A commercial glass microlens array is positioned directly over the micromirror. The use of a lenslet to focus the incoming laser beam onto the reflective surface of a micromirror substantially increases optical efficiency of the hybrid microsystem. For mirror deflections much smaller than the lenslet focal length, the lenslet/micromirror combination behaves as a phase-only modulating optical element. The hybrid lenslet/MEMS arrays thus serve as rugged, compact optical elements for beam steering, beam shaping, and aberration correction applications.

We propose a new method of assembling 3D microsystems by means of chip level electrical interconnection. Silicon dies are flip-chipped out of a silicon wafer by using ICP-RIE instead of a dicing saw. Fringes of the chips are patterned into pin-shapes so that they can be vertically inserted into the micro motherboard for electrical and physical connection. The pins are coated with Cr-Au, and the contact pads are electroplated with Cu for low contact resistance. the pins are tapered in width, and assembling was easily done by manual positing under the optical binocular microscope. This technique is a break through to the hybrid integration of various kinds of micro chips independent of materials or fabrication compatibility.

There is a growing demand for improvements in microassembly technology, especially in the area of high precision positioning. By observing the specific requirements of the micro world a spectrum of possibilities for the passive positioning supported by devices produced by conventional micromachining have been developed. By the experimental examination of different optical subassemblies an evaluation of the potentials of utilization of the passive positioning was carried out.

HAFAM is a network in training and mobility of researchers programme (TMR). The TMR Programme is a continuation of the Human Capital and Mobility Programme of the European Commission. The aim of the TMR Programme is to promote, through the stimulation of training and mobility of researchers, a quantitative and qualitative increase of human resources within Europe. The general objectives of the TMR Programme are the following: (1) to stimulate training through research and, by means of co-operation, to foster better utilization of high-level researchers in the Community; (2) to improve the mobility of European researchers throughout the Community, encouraging mobility both between universities, research institutes and industry and between disciplines, thus better exploiting the research potential in the different disciplines; (3) to promote for instance through networks, transnational cooperation between research activities proposed essentially by the researchers themselves; (4) to facilitate the access of researchers to existing large-scale facilities that are essential for high- quality research; (5) to improve the scientific and technological cohesion of the Community and contribute to the attainment of a general level of scientific institutions and researchers from all regions of the Community. Respecting this general objectives the HAFAM network and project are presented in this paper.

For the application of wireless-operated microsystems, on- chip coils are manufactured by 3D UV depth lithography and electroplating. The effects of varying the following parameters were investigated: substrate material, insulation thickness, coil material, coil structure height, coil design and the effect of using an intermediate NiFe layer. The characterization is done with the help of the measured real and imaginary part of the on-chip in a continuous frequency range of 75 kHz to 30 MHz.

A low temperature back-end process for micromachined electroplated vibrating structures has been developed. It is supposed to be processed on top of available ASIC's, independent on fabrication technology of ASIC's. Structures can be fabricate without a cap as well as encapsulated. Undesired underetching of the plating base could be overcome by an oxidation process step. Thus, the minimum width of fixed structures could be significantly reduced. To evaluate mechanical properties of electroplated moveable nickel structures, single-mass resonators have been laid out and fabricated. Moreover, the single-mass structure is representative for excitation mode of a gyroscope, which is composed of two masses, one for excitation and detection mode each. The sensor system is mechanically decoupled as the in-plane vibration modes of excitation and detection mode are perpendicular to each other. To accomplish large deflection, lateral vibration spring-mass systems are used. The resonators are electrostatically excited using comb drives. Deflections of 19 micrometers are obtained and nickel resonators show Q-factor of up to 1500. Deposition of nickel structures has been accomplished using a commercially available nickel sulfamate-based solution. Initial fatigue testing of nickel microresonators has been carried out. There is no measurable fatigue after an operating time of 250 hours.

Miniaturization is dramatically changing the shape of biotechnology. After the first wave of discoveries inventions in the field of analytical methods and DNA-probes on silicon chips, the trend in recent years has been to more complex and integrated systems in terms of microfabrication for production purposes mainly focused on polymer substrates. Additionally, an increased complexity in the biochemical functionality for tasks like cell handling, cell lysis, polymerase chain reaction, DNA-sequencing and recently in the field of proteomics research can be observed. In this paper we describe the practical approach to a polymer substrate based, microfabricated chip-based multichannel array for 2D capillary electrophoresis. This chip can be fabricated by classical mass production techniques like hot embossing or injection modeling, and has the potential for on-chip-integration of electrodes and detection system.

In this paper, a LC-SEM will be presented as observation device for micro assembly purposes. Compared to other means of magnification it offers several advantages like, for instance, a large depth of field. A gripper which can be operated inside this LC-SEM has been developed and tested. It can be equipped with an endoscope for additional process observation. Its gripping arms can be changed according to the assembly task. For precise and flexible positioning of the griper a complex 7-axes positioning system has been designed. It can be operated in the LC-SEM too, and offers a tool-center-point movement of the gripper in order to keep all assembly operations in the focus of the SEM. With these devices further study of micro assembly will be possible.

Manufacturing of micro-systems differs from IC manufacturing because the market requires a diversity of products and lower volumes per product. In addition, a diversity of micro-technologies has been developed, including non-IC compatible processes and potentially IC compatible processes. An infrastructure for the production of micro- system devices is lacking. On one side the technology for MST is available at the universities and small university related companies. On the other side there are several small and medium enterprises and bigger companies wanting to implement MST devices in their products, but unwilling to be dependent on universities. Philips Electronics in the Netherlands and Twente MicroProducts realized this problem and have started a project to fill this gap. At this moment the basic of the infrastructure is available: OnStream BV, Eindhoven, The Netherlands, opened its waferfab and assembly facilities for the production of MST devices. Twente MicroProducts will take care of the design of the products and of the small-scale production. Integration of quality systems for maintenance, yield, statistical process control and production in a Manufacturing Execution System offers direct access for all people involved to all the relevant information. It also ensures quality of the products made. The available capabilities of the infrastructure in the current status are compared to the market needs. In this article, a description of a seamless Micro-System Engineering Foundry is given. A seamless organization is capable of helping the customer from design to production. Several examples are given.

Silicon-based electret materials are presented for the application in micro-machined sensors. Various dielectric layer systems of silicon dioxide and silicon nitride are investigated and compared to the well known single layer silicon dioxide. The superior material system silicon dioxide/silicon nitride is optimized in terms of charge stability, mechanical behavior and processing capabilities. Only the advantageous combination of low stress and good electret properties allows the realization of electret membranes for silicon microphones. Electret membranes were realized by means of an anisotropic etch process. Various measurements of charge stability were performed and evaluated. For the first time the application of an inorganic electret membrane in a micro-machined capacitive silicon microphone is presented and results are shown. An equivalent noise level of 32 dB could be achieved for an electret microphone with a 4 mm² membrane area.

A dynamic characterization of SiO₂-Au composite cantilever beams and Si₃N₄-Au composite microbridges, has been performed to determine the effective residual stress in thin film-based microstructures. For the cantilever beams, the first three resonant frequencies were measured and compared to the theoretical ones obtained with a simple analytical model taking into account the effect of the gold layer on the shift of the resonant frequencies. A very good agreement is obtained between theoretical and experimental values showing the validity of the approach. Concerning the composite microbridges, the Rayleigh-Ritz method has been applied to obtain the relationship between the resonant frequencies and the effective residual stress. Using this method, the effective residual stress within the Si₃N₄-Au composite microbridges has been determined, (sigma) _eff equals 610 +/- 40 MPa.

The fine control of laser diodes emission wavelength is usually done by controlling the diode temperature and current, however, the internal wavelength selection mechanisms inside the diode cavity are not strong enough to get a complete coverage of the tuning range, and the diode wavelength usually hops to unpredictable places, leaving some wavelength intervals difficult to access.

A technology for fabricating fiber optically interrogated pressure sensors is described. This technology is based on anodic bonding of ultra-thin silicon wafers to patterned, micro-machined glass wafers, providing low-cost fabrication of optical pressure sensor heads that operate with reproducible technical characteristics in various dynamic ranges. Pressure sensors using 10, 20 and 50 micron thick silicon wafers for membranes have been fabricated on 10 cm diameter, 500-micron thick, Pyrex glass wafers. The glass wafers have been micro-machined using ultrasonic drilling in order to form cavities, optical fiber feedthrough holes and vent holes. One of the main challenges of the manufacturing process is the handling of the ultra-thin silicon wafers. Being extremely flexible, the thin silicon wafers cannot be cleaned, oxidized, or dried in the same way as normal since wafers with a thickness of the order of 400 microns. Specific handling techniques have been developed in order to achieve reproducible cleaning and oxidation processes. The anodic bonding was performed using an Electronic Visions EV501S bonder. The wafers were heated at 420 degrees C and a voltage of 1200 volts was applied in vacuum of 10^-5 Torr. The bonded wafer stack was then fixed in a wax and diced. The resulting chips have been used to fabricate operating pressure sensors.

Consideration of candidate materials for MEMS points out silicon - silicon dioxide as a dominant structures at present. This paper deals with 'Silicon Carbide - Aluminum Nitride' (SiC-AlN): a novel alternative to Si-SiO₂. The SiC-AlN composition applicability to MEMS can be substantiated by its capability to meet a number of very important MEMS-imposed requirements, such as a good compatibility and a high thermal, electric and mechanical strength of both materials. The two material: one being dielectric and the other - a wide band-gap semiconductor, when integrate in one structure, exhibit the high crystalochemical compatibility and perfectly compatible thermal expansion coefficient. Moreover, both materials have excellent heat conductances which are characteristics of their inherent perfect thermal resistance and low reactivity. In its mechanical strength, SiC yields among semiconductors to diamond only. In addition, the SiC-AlN composition combines strain gauge properties of SiC with piezoelectric properties of AlN. Besides, SiC and AlN both are optically-active up to the UV region of spectrum and may be employed both in light emitters and in photodetectors. Technologically, in application of a MEMS structure, aluminium nitride plays the role of a sacrificial layer to be selectively stripped away by an acid etchant in the epitaxial compositions SiC-AlN. The compatibility of such properties of SiC and AlN, especially in one structure, makes the SiC-AlN composition a promising candidate for MEMS-devices to be designed for the stable-performance operation under rather severe conditions.

Currently, most silicon microstructures used in microstructures are produced by photolithographic methods. The reason for this is the well-developed etching technology, used in microelectronics, that has been transferred to the microsystem domain. But since the making of an arbitrary shape or angle on silicon mainly depends on the crystal orientation, some severe limits exist in the production of 3D structures. Electro-discharge machining (EDM) is basically a thermal process. During the EDM process material is removed by electric sparking. It is therefore completely different from etching. In this work, micro-EDM is introduce as a potential approach for solving the above mentioned drawbacks. First, this work presents several testing experiments with different process parameters to investigate the influence of the micro-EDM process on the silicon structure. Main emphasis is put on the surface roughness and on avoiding microcracks generated by the sparking process. It is found that microstructures with a sufficiently low surface roughness and with small microcracks can be produced. The remainder of the work concentrates on making small beam structures, which is a common structure in many microsensor designs. It is found that for a wafer thickness of 650 micrometers , the thinnest beam that can be produced is about 30 micrometers wide. This means that micro-EDM can offer an aspect ratio of 20 in combination with a god dimensional control.

The alignment of optical elements in a MOEMS, is of prime importance in order to realize a reliable and low loss system. Fabrication errors or temperature changes deteriorate the alignment accuracy. These errors can be compensated with the aid of an active alignment system. The aim of the paper is to investigate an active system in order to align microlenses and fibers within a system. A high lateral precision is required for single mode fiber injection, typically better than 1 micrometers . With the active alignment system we can correct a misalignment of +/- 6 micrometers .

In this paper, a new microstereolithography apparatus is described. It is an integral process in which a complete layer can be made in one exposure only, in contrast to vector-by-vector processes which are based on the vectorial tracing of each layer. As for most microstereolithography processes, complex objects can be realized by superimposing layers, each layer being obtained by a light-induced polymerization of a liquid resin. The vertical and transverse resolution of the process we are developing have been measured. Complex in shape objects have been realized: small 3D polymer components have been built such as turbines, microsprings, or micropipes. They are compared of a large number of layers with a resolution better than 5 micrometers in the 3 directions of space. Some of these objects serve to demonstrate that complex in shape 3D objects can be manufactured with this technology. Sample structures which can be used in microfluidics, microrobotics or in the biomedical field are presented.

We describe a simple yet efficient technique of delineation of various polymer MEMS structures using computer driven liquid jet dispenser. A syringe-type dispenser with a replaceable needle is filled with a polymer solution and mounted on a vertical translation stage. The substrate is mounted on two-coordinate horizontal translation stage. Additional vertical translation arm is connected to the plunger of the syringe. Vertical translation provides positioning of the needle at a certain height over the substrate. Delineation is accomplished when the syringe plunger, being pushed down by the vertical translation arm, dispenses the liquid on the substrate at a programmable flow rate simultaneously with horizontal motion of the substrate with respect to the needle. Horizontal motion is done along a programmable trajectory at a programmable sped. Comparing to conventional methods, the proposed device consumes three order of magnitude less amount of material for the fabrication of similar MEMS structures. In addition, we describe a supplement to the liquid delineation system in the form of a microscope objective head connected to a noncoherent UV source with a multimode optical fiber. The head can serve as a tool for UV curing of the polymer material deposited with the jet dispenser as well as a separate UV writing tool. In conclusion, we describe the calculation technique for the distribution of the electric field in electrically or optically controlled ferroelectric polymer MEMS fabricated by the proposed technique.

Microchannel microfluidic components are being developed for heat transfer, chemical reactor, chemical analysis, and biological analytical applications. Specific applications include chemical sensing, DNA replication, blood analysis, capillary electrophoresis, fuel cell reactors, high temperature chemical reactors, heat pumps, combustors, and fuel processors. Two general types of component architectures have been developed and the fabrication processes defined. All involve a lamination scheme using plastic, ceramic, or metal laminates, as opposed to planar components. The first type is a stacked architecture that utilizes functionality built in each layer, with fluid flow interconnects between layers. Each layer of the laminate has specific microchannel geometry, and performs a specific function. Polymeric materials are used primarily. Fabrication processes used are laser micromachining, wet and dry etching, and coating deposition. the laminates can also be micromolded plastics. The second architecture employs laminates to form internal microchannels and interconnects. Materials include ceramic tapes and high temperature metals. Catalysts can be placed in the microchannels. Fabrication processes used are diffusion bonding, ceramic bonding and firing, photochemical etching, and electrochemical micromachining. Bonding, thus sealing, the laminates is an important issue. Process conditions have been develop to reduce distortion of the laminates and to hermetically seal the components.

The construction of both the backside contacts and the package for replaceable sensor structure bonding has been described in the paper. Some aspects of technological process for backside contact performance are discussed in the report too. The measurement results from the structure test proved small and stable contact resistance when sensor structures have been changed in the package more than 100 times. A new method of changeable package has been shown.

The reactive ion etching (RIE) of quartz and of silica-based glasses has been examined in CF₄/CHF₃ plasmas. The etch rate was shown to reduce strongly with an increasing percentage of non-volatile elements in the glass. The etching of the quartz and the Suprasil 2 and Herasil 2 glasses was consistent with a process of ion-enhanced chemical reaction as identified by Steinbruchel. For these substrates, the etch rate was directly dependent on the square root of bias voltage in the RIE and increased with the ratio of CF₄:CHF₃ in the gas mixture. The comparatively low etch rates of the LE, soda-lime and NA glasses were equivalent in both the CHF₃/CF₄ and Ar plasmas, indicating a process of sputter etching. The BK7 glass has shown intermediate characteristics with a higher etch rate in CF₄/CHF₃ than in Ar plasma, indicating ion enhanced chemical etching but with little dependence on the CF₄:CHF₃ gas ratio. These results have been applied in the fabrication of grating patterns.

This paper describes an application of the LIGA technology to the fabrication of optical fiber ferrule mold inserts with twelve channels. It presents the overall process from mask design, mask fabrication, deep x-ray lithography exposure, resist development, nickel electroforming, as well as surface finishing to attain the final result. Several deep x-ray mask-making methods are explored, including mechanically machined masks, micro-EDM masks, and electron beam written masks. The exposure, development and electroforming to fabricate nickel molds up to 500 micrometers thickness are reported in this study. Nickel structures for fiber ferrule mold insert with twelve channels made by electroforming are the final products. A practical method to finish the microstructure surface is presented. Channels with diameter precision -0.0/+0.5 micrometers and pitch alignment of 0.25 micrometers were accomplished to satisfy the requirements of the research sponsor for inserting and aligning 125 micrometers single-mode fibers.

Optical 1xN switches which can be operated by Giant Magnetostrictive Thin Film under the magnetic field are firstly investigated. Bulk micromachining and deposition of magnetostrictive thin film was used for fabrication of a 1xN cantilever-type optical switch. Optical switching operation induced by magnetostriction was examined through optical path modulation test. The optical path can be redirected and exactly positioned by wide reflection-angle change of light with cantilever deflection. Deflection of cantilever by magnetostriction was significantly improved in our developed Re-Fe thin film system. In this report, Giant magnetostrictive thin films of amorphous Tb-Fe and Sm-Fe based alloys exhibiting excellent magnetostrictive characteristics at low magnetic fields are developed from a systematic investigation with a particular emphasis being placed to examine B effects. Magnetostrictions of 173 ppm and -585 ppm are achieved in B containing Tb-Fe and Sm- Fe thin films, respectively, at a magnetic field of 100 Oe. Switching characteristics of our cantilever-type optical switch were evaluated using optical fiber under laser-optic test system. Optical path change of 6 degree was achieved under stable switching operation and was considered to increase the number of communication channels for construction of fiber optical network application.

The paper describes the non-contact ultra-high accurate 3D surface profile measuring system for the microstructure, whose surface structure is probably deep and discontinuous. The system is based on the dual-path two-wavelength phase- shifting interferometry and data processing/analysis. To measure the deep microstructure,the generalized two- wavelength measuring method is adopted to expand the depth measuring range. To measure the microstructure whose surface is discontinuous, a new data analysis/processing method is presented, by which the discontinuous surface can be measured without the change of the measuring system. This system has already been applied to measure the surface profile of the various actual microstructures. The results show that the depth resolution of the system is 0.5nm, the depth measuring accuracy is better than 1.3nm. When 20X microscopic lenses is used, the transversal resolution of the system is about 0.5 micrometers , the field is about (phi) 1.325 mm.

Rapid prototyping of silicon microstructures for fluidic devices using laser machining in water and abrasive-jet machining through mask is described. For laser machining a Q-switched 1-2 W 1 kHz pulsed Nd:YAG laser beam and 60 mJ XeCl excimer laser beam were used. The laser beam was scanned along the silicon surface at speeds 0.1-2 mm/s. Using excimer laser, the silicon nitride layer was patterned for subsequent chemical etching. Nd:YAG laser was used for fabrication of cavities and channels of depth down to 200 micrometers . Comparison of Nd:YAG laser machining of silicon in air and in water has been performed. Machining in water yields more even surfaces and there is no debris. By abrasive jet of velocity approximately 200 m/s and abrasive feed rate of 0.4 g/s, the silicon was eroded at speed of 40 micrometers /min. Several masking materials were compared, whereby a styrene based glue was found to have the best abrasion resistivity. The polymer masks were spun on the surface and patterned by excimer laser point or by knife. The described fabrication methods were used for making the fluid channels and chambers in silicon and for releasing silicon nitride and oxide films.

A new method is proposed to design gray-tone masks for fabrication of surface relief microstructures. Unlike previous methods which modulate the light intensity by changing the cell size or cell pitch only, the method relays on adjusting both the shape and position of a cell which gives an extra freedom to control the design accuracy. Using the new method a gray-tone mask has been designed to produce a hemispherical shape relief structure. Based on the theory of partial coherent light and the resist development model, the intensity distribution through the gray-tone mask and exposure of photoresist have been simulated. Nonlinear effects in aerial image and resist development have been taken into account to correct the mask design. The accuracy of the gray-tone mask design has been confirmed by simulation of 3D resist profiles.

The objective of the MICROMED CNRS project is the design of a complete microsystem usable in the treatment in vivo of hypertensives. The microsystem which corresponds with this objective includes different elements such as pressure sensors, a drug reservoir, a monitoring chip and a drug delivery system that necessitates the use of a dosing micropump able to deliver daily does of few microliters in several shots. We will focus here on the micropump:microfabrication technology, assembly and test. The fact that the fluid actuating membrane, the input and output fluid gates, and the two passive microvalues are together on a single silicon chip of 1 cm³ area makes this pump original. The fabrication technology combines the techniques of microelectronics and MEMS: micromachining for the square membrane and the fluid gates, sacrificial oxide layers and LPCVD polysilicon deposition for the microvalves. The assembly of the different parts is based on existing techniques like anodic bonding, gluing with adhesive films...we have investigated the fabrication of the micro pump with an electrostatic actuation. Tests are in progress for the first prototypes on a specific experimentation set- up in order to: (i) study the flowing of different fluids into the pump, (ii) study the directionality of the valves by plotting the flow rate/pressure (Phi) (P) diagram, (iii) study the pump functionality.

Selection of candidate materials and processes for manufacturing structural members is of great moment in designing surface micromechanics devices. The known arts of obtaining superficial microstructures, as a rule, with the use of a 'sacrificial' layer were based on the employment of polysilicon as a working material and of silicon dioxide as a removable 'sacrificial' underlayer. This paper proposed an art for obtaining a novel structure forming the basis for surface micromechanics. Thereby monocrystalline silicon carbide is to be epitaxially grown over a compound substrate, such as AlN-Si, AlN-Al₂O₃ or AlN-SiC. A film of aluminium nitride serves then as an orientation base for epitaxially-grown silicon carbide and also as a 'sacrificial' layer to be stripped away by an etchant which must be non-reactive both to SiC and to substrate material. The crystallochemical computability of SiC and AlN, their matching thermal expansion coefficients, and high mechanical properties of silicon carbide favor a stress decrease in movable loaded members of surface micromechanics devices, just increasing those performance stability. The paper will present some experimental results that have been obtained in designing a process for manufacturing a rotating wheel vibratory microgyroscope with a moveable SiC pendulum using a SiC-AlN composition as the base.

With the development of microspacecraft technology micropropulsion concepts are introduce for course correction, orbit insertion as well as attitude control of the microspacecraft. In this context, we have introduced a new concept of MEMS based technology microthruster responding to the spatial constraints and MEMS characteristics. The originality and advantages of these new thrusters is the use of only one solid propellant stored in a small tank micromachined in a ceramic or silicon substrate and the possibility of fabricating arrays of N addressable independently microthrusters in the same chip. The thrust force generated can be set from a few (mu) N to a few 150mN by geometrical and dimensional considerations. Fabrication and assembly of array of 16 microthrusters proved the technological feasibility and the functioning performances of this new concept of small scale thrusters.

A double mirror system has been studied and realized for purposes of Deep x-ray Lithography/LIGA. Because structuring high aspect ratio resist ask for high photon flux to maintain exposure time compatible with industrial process, hard x-ray synchrotron radiation is necessary and its broadband spectrum is normally used. However one would need to shape this spectrum on both low and high-energy parts. The former may lead to resist surface overdoes and is treated by means of appropriate filters. The later is prejudicial at resist-metallic substrate interface where high-energy photons are preferentially absorbed giving rise to extra-dose even behind absorber patterns. This may result in microstructures adhesion break down for positive resist and incomplete dissolution for negative tone ones. A mirror set up in the upstream beam-line is a correct answer to prevent these effects. The association of filters and mirror gives an adjustable band-pass filter to fit almost exposure requirements in deep x-ray lithography. Preliminary result of such a system are presented concerning its band-pass filter character, flux performances and first comparative effects on resist microstructures.

A needle-shape glucose sensor for in-situ glucose monitoring has been fabricated by surface micromachining and its characteristics were examined. The sensor consists of the needle-shaped sensing part, metal lines and pads to supply a bias voltage and measure the cell current. The sensing part is seated at the end of the needle, and it has three or four working electrodes, a counter electrode, and a reference electrode. A SOI wafer was used as a substrate and a metal layer was deposited to improve bending characteristics of the sensor as a reinforced layer. A Ti/Pt layer is deposited on the thermally oxidized layer and patterned to form cells, electrodes, and metal lines. A Ag/AgCl layer was added to form the reference electrode. And then, the edge of the sensor structure was defined and etched to form the needle shape, and the windows of the cells and the electrodes were opened using wet and dry etching. Finally, a sacrificial oxide layer was removed using wet and gas phase etching and the apparent shape of the sensor was accomplished. The needle shaped microelectrode for the glucose sensor exhibits chemically stable characteristics, and the glucose concentration-dependent oxidation current of hydrogen peroxide produced by the conversion of glucose and oxygen at the working electrode, were measured.

We have proposed a surface-micromachined microflow sensor to solve the problems of poor thermal isolation and low sensitivity presented in typical thermal flow sensors. The membrane of insulating films on a vacuum cavity formed in a silicon substrate supports a n+) poly-Si heating resistor and two bidoped poly-Si thermopiles. We have investigated heat-transfer characteristics of the sensor microstructure with the 5-micrometers -depth cavity of 100 X 100 micrometers ² and nitrogen and water as the working fluid using a 2D numerical analysis in terms of the hater power, inlet flow velocity and pressure inside the cavity. The microstructure with the vacuum cavity shows improved thermal isolation compared to the air cavity, suppressing heat loss from the heater to the substrate. With the vacuum cavity heaving an optimized geometry, it is possible to enhance the performance of the thermal microflow sensor.

A microgyroscope, which vibrates in two orthogonal axes on the substrate plane, is designed and fabricated. The shuttle mass of the vibrating gyroscope consists of two parts. The one is outer shuttle mass which vibrates in driving mode guided by four folded sprints attached to anchors. And the other is inner shuttle mass which vibrates in driving mode as the outer frame does and also can vibrate in sensing mode guided by four folded springs attached to the outer shuttle mass. Due to the directions of vibrating modes, it is possible to fabricate the gyroscope with simplified process by using polysilicon on insulator structure. Fabrication processes of the microgyroscope are composed of anisotropic silicon etching by RIE, gas-phase etching of the buried sacrificial oxide layer, metal electrode formation. An electromechanical model of the vibrating microgyroscope was modeled and bandwidth characteristics of the gyroscope were analyzed firstly. The analyzed characteristics of the gyroscope were evaluated by experiment. The gyroscope operates at DC 4V and AC 0.1V in a vacuum chamber of 100mtorr. The detection circuit consists of a discrete sense amplifier and a noise canceling circuit. Using the evaluated electromechanical mode, an operating condition for high performance of the gyroscope is obtained.

Crack-free ferroelectric thin films of lead zirconate titanate with thickness of 3 micrometers for microactuators were fabricated using Sol-Gel spin-coating onto Pt/Ti/SiO₂/Si substrates. The precursor solution was prepared from lead acetate, zirconium-n-propoxide and titanium tetraisopropoxide. 2-propanol was used as the solvent. The crystalline phase as well as preferred orientation in the PZT films were investigated using x-ray diffraction analysis. The microstructure and composition of the films were studied by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy, respectively. The well-crystallized perovskite phase and the preferred orientations in the direction of the (100) plane were obtained using the heat treatment for dry at 120 degrees C, for pyrolysis at 300 degrees C and for crystallization at 600 degrees C. The prepared films showed nanometer grains with smooth and uniform surface. The dielectric constants and loss values of these films measured at 1 kHz were approximately 1250 and 0.04, respectively, while the remnant polarization and the coercive field were 45.5 (mu) C/cm² and 58.5 kV/cm. Our results suggest that fabrication of good structural quality PZT films of a few micrometers thick for use in micro actuators is possible.

We employed a newly developed HF gas-phase etching (GPE) process for the removal of sacrificial oxides. The structural layers are P-doped multi-stacked polysilicon and silicon epi-layer of SOI substrates and sacrificial layers are TEOS, LTO, PSG, and thermal oxides on silicon nitride or polysilicon substrates. The characteristics of residual products on polysilicon or silicon nitride were scrutinized by using SEM and AES. After GPE of TEOS, LTO, and PSG on the silicon nitride substrate, the polysilicon microstructures are stuck to the underlying substrate because neither the SiO_xN_y layers nor the H₃PO₄(H₂O) layer vaporize. We found that the etching of TEOS, LTO, and thermal oxide on a polysilicon substrate shows no residual product and no stiction.

We report on the design, fabrication, and characterization of a microheater module for chemoresistive, metal-oxide semiconductor gas sensors, consisting of a dielectric stacked membrane, micromachined from bulk silicon and with an embedded polysilicon resistor heater. Fabricated structures exhibit excellent heating efficiency, requiring only 30 mW to achieve a temperature of 500 C. Measured electrothermal characteristics are in good agreement with the outcomes of 3D numerical simulations.

Tetra-methyl ammonium hydroxide (TMAH) is an anisotropic silicon etchant that is gaining considerable use in silicon sensor micromachining due to its excellent compatibility with CMOS processing, selectivity, anisotropy and relatively low toxicity, as compared to the more used KOH and EDP etchants. In this paper, the influence of temperature and concentration of the TMAH solution together with oxidizer additions is studied in order to optimize the anisotropic silicon etching for MEMS fabrication. In particular this optimized etchant formulation has been employed at ITC-Irst in the development of a basic fabrication process for piezoresistive pressure sensors based on a silicon membrane and four resistors connected in a Weatherstone bridge configuration. The active element of the sensor, i.e. the thin silicon membrane, is formed by etching anisotropically from the backside of the wafer. Both process and etching have to be tuned and matched in order to obtain an optimum fabrication sequence. Some improvements such as higher etch rate and better surface finish have been obtained by the addition of ammonium peroxidsulfate as oxidizing agent under different conditions. This simplifies both the post processing and the tech set-up. The process parameters and the thermo-electro-mechanical characteristics of the pressure sensors were tested and are compared with the analytical and numerical simulations.

We investigated a new method of measuring fatigue characteristics of thin films under uniaxial loading conditions. A specimen and loading system are integrated on a same silicon ship. The size of the chip is 12 by 12 by 0.4 mm, and of the specimen 400 by 80 by 7 micrometers . Accuracy of the stress and strain measurement using the proposed loading system was proved by our previous work under static conditions. In this paper, high frequency of tensile stress was applied to the specimen by resonant mode of vibration of the loading mechanism. The loading system vibrated at the first mode resonant frequency. To vibrate the loading system, the chip was mounted on a PZT actuator, and driven by a pulse generator. The amplitude of the applied strain was measured by observing a laser reflection on the vibrating lever of the loading system, while the wave from and the vibration cycle were monitoring by an oscilloscope. The resonant frequency of the chip was 4-5 kHz.

Residual stress and stress gradients play an important role in determining equilibrium shape and behavior of various Si surface-micromachined devices under applied loads. This is particularly true for system having large-area plates and long beams where curvature resulting from stress can lead to significant deviations from stress-free shape. To gain better understanding of these properties, we have measured the equilibrium shapes of various structures built on the MCNC MUMPs using an interferometric profiler. The structures were square plates and long beams composed of various combinations of polysilicon an oxide layers. Some of the structures had additional MUMPs metal layer on top, while on others in-house chromium-gold stacks of varying thickness have been deposited. Temperature dependence of the curvature was measured for some plates. We have used these data in conjunction with simple models to significantly improve the performance of our micromachined devices. While for some structures such as large area reflectors the curvature had to be minimized, it could be advantageously exploited by others, for example vertical actuators for self-assembly.

Scanning spreading resistance microscopy (SSRM) and scanning capacitance microscopy (SCM) are two different methods for carrier profiling on semiconductor devices based on the atomic force microscope (AFM). The crucial part of these characterization tools is the tip which should have a small radius of curvature and a high electrical conductivity. Therefore, we have developed a process for the fabrication of pyramidal metal tips which are integrated into a silicon cantilever. The fabrication scheme is presented and is discussed in more detail from the point of view of batch fabrication. The fabricated probes were used in the AFM for topography measurements and for electrical measurements. We demonstrate that these probes can be operated in contact mode as well as in tapping mode. The behavior of the metal tips in carrier profiling was extensively studied. Results are presented concerning the application of such probes for 2D SCM measurements on silicon and InP device structures. We demonstrate that silicon cantilevers with integrated metal tips are very well studied for SSRM measurements on InP structures.

The change in the SAW phase velocity due to the presence of a TiO₂ thin film of the propagation surface of a piezoelectric substrate has been used for the determination of the elastic constant of the layers. The relative change (Delta) v/v in the SAW phase velocity v₀ is expressed, using the perturbation theory, in function of the material density and of the elastic constants of the film. A comparison between the values of (Delta) v/v obtained with exact calculations, the approximate theory and the experimental values allowed us to evaluate the physical constants of TiO₂ films to be used as sensitive membranes in relative humidity sensors applications.

Devices for mass separation have been engineered and were fabricated using the AMANDA process. The key component is a 5 micrometers thin, semi-permeable PTFE membrane with a circular diameter of 42 mm. The membrane is encapsulated in a PTFE and PEEK housing. In experiments, this novel device separated a gas flow of approximately 1 (mu) l/min from a methanol feed stream of 1 ml/min at a pressure difference of 900 hPa. The separation process was simulated in FE- calculations exploiting analogies between diffusion theory and heat transfer. Mechanical stability and creeping of the PTFE membrane were investigated as well. All parts in contact with the fluids to be separated are made of chemically inert polymers. As a consequence, a welding process had to be developed for bonding the PTFE membrane to the PTFE housing. This was accomplished with an intermediate FEP layer. Extension of this bonding technique to other AMANDA products will facilitate fabrication of chemically inert micropumps, valves, and sensors.

This work fabricates a laminated-suspension microwave switch using the conventional CMOS process. The proposed microwave switch is fully compatible with an IC foundry service, and the post-process is completed with maskless dry-etching. In addition, the switch only requires a low dc voltage of around 18 V for electrostatic traction. This novel design corresponds to the 0.6 micrometers 3-metal CMOS process. A micromachined microwave switch consists of two electrostatic parallelogram actuators, two T-type connectors and one coplanar waveguide (CPW) on p-type silicon substrate. The microstructures are suspended over silicon substrate by maskless dry-etching oxide and silicon. Without an applied voltage, the actuators do not affect the CPW, accounting for why T-type connectors of actuators do not couple to microwave propagation. With an applied voltage, dc voltage is applied to the actuators to make T-type connectors contact with the signal line of CPW. The capacitance coupling becomes significantly larger than the first one to intercept microwave propagation.

In order to develop a micropump driven by shape memory actuation, we require a TiNi diaphragm structure with a cap to act as a chamber for applying bias pressure to the diaphragm. With the purpose of realizing such a structure, we studied the photoetching of TiNi thin film on a Si substrate and two bonding processes-diffusion bonding and anodic bonding- for patterning and assembling. TiNi thin film deposited on Si substrates by flash evaporation was etched in HF/HNO₃/H₂O solutions using negative photoresist masks. HF:HNO₃:H₂O equals 1:1:4 solution proved capable of etching it at a rate of about 30 nm/s without etching of the Si substrate. Patterned TiNi thin film of 6 micrometers in thickness on a Si substrate was diffusion bonded to another Si substrate coated with the same TiNi thin film at a thickness of 300 nm. Bonding was conducted in a vacuum at a bonding pressure of 210 MPa. TiNi-TiNi diffusion bonding was obtained at temperatures of more than 300 degrees C. A 4-point bending test revealed that the bond strength of specimens bonded at 400 degrees C was 15-20 MPa. Anodic bonding was conducted between TiNi thin film on a Si substrate and a Pyrex 7740 glass substrate at an applied voltage of 600 V. Two substrates were bonded in nitrogen ambient at temperatures of more than 350 degrees C, giving a bond strength of about 15 MPa at 400 degrees C bonding.

Hot embossing is an inexpensive method for the reproduction of microstructures. It has matured during the last few years from a pure laboratory method to an industrially applicable process. As an example, the technology for the production of movable metallic microstructures by aligned to embossing and reactive ion etching is presented, which has been developed at the Forschungszentrum Karlsruhe/IMT.

In this paper we will present methods for displacement characterization of topology optimized electro-thermal microactuators. Although thermal actuators are the object of our research, these methods are general in nature and can be applied for any type of laterally driven actuator. Characterization of these actuators is done by recording the power dissipated in the actuator and, by the use of a framegrabber, grabbing a microscope image of the work-point of the actuator. From the microscope images displacement information is found by image analysis. Using the presented method, displacements can be measured with a resolution of 5 nm. This highly accurate displacement measuring method is used to calculate displacement distributions form which the strain distribution can be calculated.

This paper present the results from the investigation of the chemical anisotropic etching of single-crystal silicon in the following solutions: KOH, K₃[Fe(CN)₆] 0.1M, K₄[Fe(CH)₆] 3H₂O 0.1M, KNO₃ 0.1M and/or complexant added. The complexants added in KOH solution were: Calix(4)arenes, Phenols and Ether Dibenzo 18 Crown 6. The result using also NaOH or LiOH H₂O and complexants are presented. The reaction mechanism and the hillocks formation and elimination are analyzed. The results allow us to use the redox system and/or the organic complexants, to monitor the etching process, to obtain a smooth silicon surface, almost free of hillocks, to utilize the usual mask material resistant at the new etchants.

This paper describes the fabrication of a new type of metal stencil mask. By using electrodeposited (ED) photoresist in an electrophoretic bath, conformal layer is deposited on both sides of a copper foil, making thus possible double side photolithography. After the exposure through two well aligned mask, containing the structure, and the developing of the photoresist, the copper foil is simultaneous selective electroless nickel deposited on both sides, allowing the stress in the sandwich structure nickel films to balance each other. Transmission holes are etched entirely through the copper membrane resulting in an inherent stress compensated metal stencil mask. The attainable 5 micrometers resolution and high reliability offered by stress compensation of this kind of metal stencil, open very exciting possibilities for low costs selective deposition of metals and insulators in microelectronics, micromechanics and optoelectronics.

This is an artificial photoreceptor based on an organic polymer photocell. This organic polymer is bacteriorhodopsin (bR) derived from the purple membrane of Halobacterium Halobium. Also the retina itself uses this dye, rhodopsin, for the light-to-electricity conversion. When the light strikes the film, the dye molecules respond by changing shape. This change creates a displacement of charge, which generates an electrical signal through the electrode. Because the protein relaxes back to its original shape when the light hitting it remains constant, the protein delivers just a quick pulse of current to the electrode and then sends nothing more until the light intensity changes again. Parallel computation based on neurobiological principles is presently a great interest in terms of both advancing our knowledge on the fundamental basis of how the brain works and developing devices that can emulate neural networks. This study focuses on image detecting like that processing in the human eye. We also enlighten the possibility to simulate the visual perception by choosing the right design for our photoreceptor, in this view we imagine an original cell-like architecture to hold the bR purple membrane.

The increase in the etching rate of both n- and p-type silicon was obtained under cathodic biasing in alkaline solutions. In the case of n-silicon the acceleration of the etching rate in dark was found to be markedly enhanced by illumination. The high rate of etching of p-silicon at cathodically applied voltage was obtained only with illumination. When the process was carried out at potentials more negative than -10 V it provoked electropolishing of the etched surface. Shifting the potential in the cathodic direction increase the etch-rate and enhances the effect of polishing. The etch-rate increased by more than two orders of magnitude over the potential range from -10 to -50 V, and reached the values above 200 micron/hour.

The microfabrication of silicon V-grooves allows to obtain very good positioning accuracies, it is therefore often used for precise alignment of optical fibers. In many cases, it is necessary to etch at the same time V-grooves with variable widths, or V-grooves crossing eachother. In such commonly encountered case, well-known overetching effects appear, leading to structures that are quite uncontrolled in size and depth. Corner compensation methods can reduce such effects to some extent, in some cases. In this report, we present another method which can be used to minimize convex angels overetching. This method can be used alone or in addition to classical corner compensation methods. In some cases, it could even be used when such methods are not possible. We first present the convex angle overetching, and derive the relation between underetching and etching depth. The method relies on discontinuities of the mask, which allow to keep a precise etching geometry until the discontinuity is underetched: the beginning of the corner underetching is thus delayed while the wanted structure is etched with a high accuracy. The control of the underetching rate is obtained through a precise alignment between the mask edges and the crystal orientation. The experiments show that our method allows to reduce significantly the overetching of convex angles. This method is useful to improve or simplify the fabrication of several kinds of microstructures for MEMS or MOEMS applications. We show how it makes feasible a microstructure which mixes closely spaced V-grooves and metal interconnection lines, and how it can improve the fabrication of crossing microchannels.

DEM technique developed by present authors is a new 3D micro fabrication technique for non-silicon materials such as metals, plastics and ceramics. In comparison with LIGA technique, it does not need expensive synchrotron radiation source and x-ray masks. DEM technique has both advantages of bulk silicon micro fabrication technique and LIGA technique. In the present research, we obtained metallic mold insert with structure depth of 180 micrometers and aspect ratio more than 20. A successful development of DEm technique opens a new way for 3D micro fabrication of non-silicon materials.

A laser-assisted technology for the fabrication of micro electro mechanical system has been developed. This method allows micromachining of bulk silicon wafers and silicon membranes by using a Q-switched Nd:YAG-laser with optional frequency doubling. Moreover, thin gold film resistors can be patterned on passivated silicon and glass substrates. Because direct laser processing is a highly flexible and timesaving method it is well studied for rapid prototyping and small volume production. Combining laser micromachining with conventional photolithographic techniques new designs of microsensors and actuators can be achieved.

Micro-electrodischarge machining is used to machine small features such as holes, cavities and slots with high aspect ratios in electrically-conductive materials for various applications including medical implants, printing devices, dies and spray nozzles. In this study, the positional accuracy of a micro-EDM machine was assessed while simulating the machining of an array of holes. The measurement involved the use of a diffraction grid plate and non-contact scanning head. This enabled various conclusions to be drawn as to the relative deviations experienced when machining small features such as (phi) 50 micrometers holes.

AFM probes consisting of a diamond cantilever and a diamond tip were fabricated using a newly developed micromachining process based on the CVD of diamond film. The tips were fabricated by diamond deposition onto a Si mold formed by anisotropic etching in a KOH solution. It was possible to realize a sharp diamond tip with an apex radius of less than several tens of nm. The cantilevers were fabricated by selective deposition of diamond film patterns. This process was realized by mechanically damaging the substrate surface and subsequent pattern etching of the damaged layer, leaving a damaged pattern of high nucleation density on the substrate surface. Finally, the base of the fabricated diamond probe was coated with an Al layer by evaporation and then attached to a glass backing plate with epoxy adhesive to facilitate handling. We also discuss the possibility of attaching the glass backing plate by anodic bonding to further increase accuracy. Applying the fabricated V-shaped and rectangular diamond probes to measurements on a commercial AFM system, it was demonstrated that they were capable of obtaining AFM images.

In this paper, we present a detailed study of the effect of the interface in multi-stacked polysilicon film. In order to investigate microstructural stress characteristics, we fabricated laminated type 2 micrometers thickness of polysilicon test structures such as bridges and rotating beam pairs. Also the characteristics of the various doping and deposition method, and annealing treatment are examined through the SIMS analysis. The relative interface location was carried by changing the film thickness for each deposition step and this was compared with 2 micrometers thick film deposited at a time. We found that the interface is one of the key factors deciding the stress gradient in multi- stacked polysilicon film but the residual stress is independent of the interface location. Finally, on the basis of the result, fabricated a test pattern of the multi- stacked polysilicon microstructure with thickness of 6.5 micrometers using the symmetrical stacking and doping method has a low stress of 7.6 MPa and a low stress gradient of -0.15 MPa/micrometers .

The paper presents the integration ont he same chip of: Mach-Zehnder interferometers and Y junctions based on SiON waveguides, 3D movable micromechanical structures, optical couplers and photodetectors for optical read-out. The SiON low loss optical waveguides were fabricated by LPCVD processes, compatible with CMOS technology. The diaphragms, used for pressure sensing, obtained by p⁺ etch stop techniques, were placed under the sensing arm of the interferometer. The cantilevers, used in micromechanical resonators were manufactured by front side micromachining. The optical waveguides were coupled with different types of photodetectors, for optical read-out. Also experiments for hybrid integration of an emitting device have been performed. We used an AlGaAs emitting diode, with high edge emission, mounted in a silicon groove, on the same wafer with the sensor. The lateral emitted light is coupled in the waveguide. One of the main problems that had to be solved will be the matching of all the involved technologies. The result of our research is the demonstration of the compatibility between the technological process involved and the possibility of integration on the same silicon substrate of different components: waveguides, photodiodes, emitting devices, 3D movable microstructures in order to realize intelligent microsensors.

Sol-gel organic synthesis of SnO₂ thin films from tin ethoxide precursor is reported here as a promising and cheap alternative of the 'classical' chemical and physical preparation methods of the SnO₂ thin films, for gas sensing applications. A simple, integrated circuit compatible test structure, for rapid evaluation of the sensing properties of the SnO₂ sol-gel derived thin films is described. The main features of our microstructure consists of a a heating resistor integrated on chip, made of highly boron doped silicon and a metallization system from Au/W deposited on a planarized chemically vapor deposited SiO₂ layer. The SnO₂ films have shown the well-known increase-maximum-decrease dependence of chemoresistance as a function of temperature, with a maximum at about 380 degrees C, when they are measured in clean, dry air. The sensitivity of SnO₂ films to high concentration of H₂ in air was studied within a quartz furnace, externally heated in the temperature range from 200 to 450 degrees C. The relative sensitivity is equal to 100 percent at temperatures as low as 200 degrees C, while its maximum value is anticipated to be above 450 degrees C. The CO sensing properties of SnO₂ layers were evaluated as a function of input power applied on the integrated heating resistor. We have obtained relative sensitivities of 30 percent for 500 ppm CO concentration in dry air and an input power of 209 mW.

In this paper we present a new microdevice used for the anodic oxidation of organic compounds. It has as component parts an electrochemical micropump, 2 microreservoirs and a reaction chamber. the electrochemical micropump is electrochemical-pneumatic actuated, using an electrochemical generated gas as fluid motor. The volume of reaction chamber is 1.5 cubic mm and is equipped with working electrode, counterelectrode and reference electrode. Anisotropic etched silicon was used as construction material, Pt thick films and Ag/AgCl were used as electrode materials. Using this device, the anodic oxidation of 4-hydroxy-1,3- phenylendiammoniumdichlorid was performed.

The anodically etched macroporous and nanoporous silicon layers (PS) were tested in order to determine their surface roughness dependence eon fabrication method. Porous silicon layers were obtained by electrochemical etching of n-type wafers, and then highly doped. Deep P⁺ layers were prepared by boron diffusion into the PS from spin-on glass glasses. The structure of PS surface of solar cells obtained was examined by atomic force microscopy. The system of PS coated with nanoporous PS as a antireflection coating exhibited a uniform macroarray of regular square and faceted large features of various sizes as a texturisated solar cell with average 1.43 micrometers high and computed roughness parameter R_z - 2.37 micrometers . For the same macroporous silicon sample without additional nanoporous silicon layer computed R_z was 4.84 micrometers . This could be explained by electropolishing of macroporous silicon surface. The obtained results confirm that AFM can be employed for the accurate measurement of the shape of macroporous silicon covered by the nanoporous silicon layer.

The availability of very sharp, wear-proof, electrically conductive probes is one crucial issue for conductive AFM techniques such as SCM, SSRM and Nanopotentiometry. The purpose of this systematic study is to give an overview of the existing probes and to evaluate their performance for the electrical techniques with emphasis on applications on Si at high contact forces. The suitability of the characterized probes has been demonstrated by applying conductive AFM techniques to test structures and state-of- the-art semiconductor devices. Two classes of probes were examined geometrically and electrically: Si sensors with a conductive coating and integrated pyramidal tips made of metal or diamond. Structural information about the conductive materials was obtained by optical and electron microscopy as well as by AFM roughness measurements. Swift and non-destructive procedures to characterize the geometrical electrical properties of the probes prior to the actual AFm experiment have been developed. A number of analytical tools have been used to explain the observed electrical behavior of the tested probes.

This paper presents the technological processes developed in order to obtain high quality 1.5micrometers membranes on high resistivity (100) and (111) oriented silicon. To emphasize the outstanding characteristics of the membrane supported elements, coplanar meander-line, 'S'-line and square spiral inductors, as well as interdigitated capacitors were designed and manufactured both on dielectric membranes and on bulk SI GaAs substrates, and their equivalent circuit was developed, too. An improvement of the measured resonant frequencies by a factor of 1.7 to 1.8 was noticed. Equivalent circuits, able to simulate the behavior of the coplanar elements up to twice their resonance frequencies, were developed. The paper brings into relief, quantitatively, the superiority of the membrane supported microwave planar lumped elements.

Phenomenal advances in MicroElectroMechanical Systems (MEMS) performance has made this technology attractive for the development of micro- and nano-spacecraft. However, much work remains to be done. The space environment is harsh: extreme heat and cold, thermal cycling, radiation effects, and corrosive environments put conventional device designs at risk. Reliably, packaging and flight qualification methodologies need to be developed for MEMS to produce robust devices for a successful future in space micromissions. These issues are discussed in this paper, along with examples of micromissions, MEMS devices in development for space applications, and the ultimate in device integration: a system-on-a-chip.

In the development of microdevices and microsystems, computer simulations constitute a cost-effective and time- saving alternative to the traditional experimental approach by 'straightforward trial and error'. Application-oriented modeling does not only allow the visualization of fabrication processes and operational principles, but it also assists the designer in making decisions with a view to finding optimized microstructures under technological and economical constraints. The long-term vision is the automated optimization of microsystems according to customer-supplied specifications in a computer-based 'virtual factory' prior to the real fabrication. To this end, strong efforts have to be made towards a predictive 'CAD tool box' for top-down and closed-loop simulation of microsystems. We discuss the most important aspects to be focussed on and practicable methodologies for microdevice and system modeling such as the consistent treatment of coupled fields and coupled domains, physically-based models for full system and mixed-mode simulation, and the reliable validation and calibration of models.

Facile, integrated and comprehensive software is needed for the design of processes, models and simulation, which are required for effective production of MEMS and microsystems. The characteristics of computer-aided design software now available from seven companies are reviewed. Three of the firms have roots in microelectronics, and three were formed specifically for MEMS design. Electronic, mechanical, thermal and fluidic mechanisms are commonly included. One company is especially strong in microfluidics. Two of the design suites permit computational coupling between a MEMS device and its package. High spatial- and temporal- resolution optical diagnostics are now producing detailed data that will challenge design and simulation software for MEMS and microsystems. Near and far term prospects for the CAD of MEMS and microsystems are projected.

The state of the art of III-V semiconductor based Micro- Opto-Mechanical Systems (MOEMS) is presented with a special emphasis on InP and related materials. It is shown that the MOEMS technology can enhance considerably the capabilities of optical micro-cavities, which are considered as a major component for optical signal processing and light generation. Illustrations of the potential of III-V MOEMS are given in the fields of Optical Telecommunications and Near-IR photodetection. Future prospects implying the marriage of MOEMS approach with Photonic Band Gap concepts are proposed.

The synergy that exists between MEMS technology and free- space optics can be exploited to provide low cost solutions to many of the problems arising in modern dynamic WDM networks. We describe an optical modulator, an electrically controlled variable attenuator, a WDM equalizer, and a programmable wavelength add/drop system.

This paper describes several silicon micromachined devices that have been developed at NEC from the viewpoint of commercial applications. The author learned it was difficult to continually succeed in business, even if the related technology could be established. It is supposed that the market for micromachined devices will soon become saturated, leading to strong cost competition and declining profitability. On the other hand, the potential wide applications for MEMS will allow many companies to develop their own specialties in the future.