Dr. Christian K. Kalus Profile

Dr. Christian K. Kalus

Chief Technical Officer

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Author

Publications (18)

Proceedings Article | 2 May 2008 Paper

Three dimensional mask effects in OPC process model development from first principles simulation

Lawrence Melvin, Thomas Schmoeller, Christian Kalus, Jianliang Li

Proceedings Volume 6792, 679207 (2008) https://doi.org/10.1117/12.798520

KEYWORDS: Photomasks, 3D modeling, Optical proximity correction, Data modeling, Process modeling, SRAF, Data processing, Computer simulations, Electromagnetism, Lithography

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32 nm half-pitch node processes are rapidly approaching production development, but most tools for this process are currently in early development. This development state means that significant data sets are not yet readily available for OPC development. However, several printing effects are thought to become more prominent at the 32 nm half-pitch node. One of the most significant effects is the three dimensional (3D) mask effect where the mask transmittance and phase are impacted by the mask topography. For the 32nm node it is essential that this effect is correctly captured by the OPC model. As wafer data for the 32nm half-pitch is difficult to obtain, the use of rigorous lithography process simulation has proven to be invaluable in studying this effect. Using rigorous simulation, data for OPC model development has been generated that allows the specific study of 3D mask effect calibration. This study began with Kirchhoff based simulations of 32 nm node features which were calibrated into Hopkin's based OPC process models. Once the standard Kirchhoff effects were working in the OPC model, 3D mask effects were included for the same data by performing fully rigorous electromagnetic field (EMF) simulations on the mask. New EMF compensation methodologies were developed to approximate 3D mask effects in a fast OPC process simulation. These methodologies modify the phase and transmission of features to compensate for 3D mask effects in a fast OPC model. The OPC model was then refit including the 3D mask effect and found to generate as much as 5 nm differences between the fit Kirchhoff data and the fit 3D mask data. In addition, the Hopkin's based OPC model with new EMF compensation methodologies has been able to fit the 3D mask data with an RMSE value of 0.52 nm and a range of 2.76 nm. These data were compared to 32 nm half pitch node data from IMEC. In addition the data process models were used for OPC correction with first principles validation to understand the impact of the 3D mask effect on OPC.

Proceedings Article | 15 March 2006 Paper

In quest of predictive lithography simulation

Christian Kalus, Hinderk Buß, Peter Brooker

Proceedings Volume 6154, 61541S (2006) https://doi.org/10.1117/12.654770

KEYWORDS: Mathematical modeling, Lithography, Diffusion, Optical lithography, Photoresist materials, Systems modeling, Process modeling, Differential equations, Calibration, Finite element methods

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Proceedings Article | 2 June 2004 Paper

Towards systematic CD process control for e-beam lithography

Christian Kalus

Proceedings Volume 5504, (2004) https://doi.org/10.1117/12.568025

KEYWORDS: Reticles, Photomasks, Manufacturing, Process control, Electrons, Optical spheres, Electron beam lithography, Lithography, Optical proximity correction, Semiconducting wafers

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The paper proposes a method to mitigate the ever tighter requirements for mask CD uniformity. The basic idea is simple. As the mask error enhancement factor (MEEF) soars at low k1 values with pitches getting smaller it sould be possible to alleviate the problem given there is a way to increase the pitch. For highly repetitive layouts like cell fields of DRAMs the solution is rather straightforward. One has to find the next larger pitch in the layout and divide the layout into sublayers. Those sub-layers are written into separate reticles for subsequent exposure. In consequence, the method will lead to double exposure in case two reticles have been generated. The simplest example is an array of lines and spaces with equal pitch. An almost trivial example, a regular square contact array, results in two equal checkerboards. The diagonal (1,1) in the square array is the second smallest pitch in a square array. To fully cover a square array requires two checkerboards separated by the base vector (1,0) of the original lattice. These two checkerboards will subsequently be printed by a double exposure. It is obvious that the pitch can be increased by choosing larger displacements at the cost of more sub-layers. Doubling the pitch, which makes manufacturing of masks a lot easier, would require four reticles, hence four exposures. The edges and corners of regular arrays print significantly different as the MEEF is position dependent. It can be expected that increasing the pitch is also beneficial in the sense that it levels off the MEEF variance. It will be investigated how much the common process window increases. The applicability of said method is obvious for memory layouts. It can however, be extended to semi-periodic or even random layouts. Its value depends primarily on the density of the layout and on the k1 value. Its potential uses comes in only at the leading edge of lithography where the MEEF starts to become a real pain for the mask maker. Simulation results will be shown as well as calculations of the process latitude before and after dividing the layout.

Proceedings Article | 17 December 2003 Paper

Rigorous simulation of defective EUV multilayer masks

Christoph Sambale, Thomas Schmoeller, Andreas Erdmann, Peter Evanschitzky, Christian Kalus

Proceedings Volume 5256, (2003) https://doi.org/10.1117/12.518049

KEYWORDS: Photomasks, Reflectivity, Extreme ultraviolet, Multilayers, Near field, Finite-difference time-domain method, Extreme ultraviolet lithography, 3D modeling, Image segmentation, Lithography

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Proceedings Article | 19 November 2003 Paper

Rigorous simulation of lithographic exposure of photoresist over a nonplanar wafer

Andreas Erdmann, Christian Kalus

Proceedings Volume 4829, (2003) https://doi.org/10.1117/12.530047

KEYWORDS: Lithography, Semiconducting wafers, Photoresist materials, Photomasks, Diffraction, Finite-difference time-domain method, Microelectronics, Computer simulations, Silicon, Light wave propagation

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Proceedings Article | 26 June 2003 Paper

Rigorous simulation of exposure over nonplanar wafers

Andreas Erdmann, Christian Kalus, Thomas Schmoeller, Yewgenija Klyonova, Takashi Sato, Ayako Endo, Tsuyoshi Shibata, Yuuji Kobayashi

Proceedings Volume 5040, (2003) https://doi.org/10.1117/12.485390

KEYWORDS: Semiconducting wafers, Photomasks, Lithography, Diffraction, Photoresist materials, Computer simulations, Finite-difference time-domain method, Electromagnetism, Silicon, Reflectivity

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Proceedings Article | 16 June 2003 Paper

Efficient simulation of light diffraction from three-dimensional EUV masks using field decomposition techniques

Andreas Erdmann, Christian Kalus, Thomas Schmoeller, Andreas Wolter

Proceedings Volume 5037, (2003) https://doi.org/10.1117/12.482744

KEYWORDS: Photomasks, Computer simulations, Near field, Extreme ultraviolet, Finite-difference time-domain method, Reflectivity, Diffraction, 3D image processing, 3D modeling, Electromagnetism

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Proceedings Article | 16 August 2002 Paper

Application of lithography simulation in reticle inspection

Christian Kalus, Robert Wildfeuer

Proceedings Volume 4764, (2002) https://doi.org/10.1117/12.479362

KEYWORDS: Inspection, Reticles, Thin films, Cadmium, Lithography, Optical lithography, Optical simulations, 3D modeling, Performance modeling, Diffusion

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Proceedings Article | 16 August 2002 Paper

Elements of hierarchical mask data preparation

Christian Kalus, Michal Simecek

Proceedings Volume 4764, (2002) https://doi.org/10.1117/12.479334

KEYWORDS: Optical proximity correction, Mask making, Integrated circuits, Computer science, Data processing, Photomasks, Explosives, Scattering, Electron beams, Manufacturing

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Proceedings Article | 1 August 2002 Paper

Integrating real-time CD corrections into a laser pattern generator

Steven Haddleton, Lars Ivansen, Michal Simecek, Uwe Schnitker, Lars Stiblert, Manfred Enzinger, Wolfgang Roessl, Mats Sundqvist, Christian Kalus

Proceedings Volume 4754, (2002) https://doi.org/10.1117/12.476922

KEYWORDS: Critical dimension metrology, Photomasks, Manufacturing, Scattering, Data corrections, Diffusion, Etching, Calibration, Electron beam lithography, Explosives

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Proceedings Article | 1 August 2002 Paper

Generic hierarchical engine for mask data preparation

Christian Kalus, Wolfgang Roessl, Uwe Schnitker, Michal Simecek

Proceedings Volume 4754, (2002) https://doi.org/10.1117/12.476930

KEYWORDS: Photomasks, Manufacturing, Data processing, Chemical elements, Image processing, Semiconducting wafers, Optical proximity correction, Phase shifts, Explosives, Scattering

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Proceedings Article | 1 August 2002 Paper

Modification of boundaries conditions in the FDTD algorithm for EUV mask modeling

Alexandre Vial, Andreas Erdmann, Thomas Schmoeller, Christian Kalus

Proceedings Volume 4754, (2002) https://doi.org/10.1117/12.476992

KEYWORDS: Extreme ultraviolet, Photomasks, Finite-difference time-domain method, Reflectivity, Diffraction, Lithography, Algorithm development, Extreme ultraviolet lithography, Matrices, Computer simulations

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Proceedings Article | 30 July 2002 Paper

Accuracy of new analytical models for resist formation lithography

Juriy Malov, Christian Kalus, Henning Muellerke, Thomas Schmoeller, Robert Wildfeuer

Proceedings Volume 4691, (2002) https://doi.org/10.1117/12.474506

KEYWORDS: 3D modeling, Photoresist processing, Absorption, 3D image processing, Lithography, Process modeling, Optical lithography, Algorithm development, Diffusion, Photoresist materials

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Proceedings Article | 5 July 2000 Paper

Optimizing edge topography of alternating phase-shift masks using rigorous mask modeling

Christoph Friedrich, Leonhard Mader, Andreas Erdmann, Steffen List, Ronald Gordon, Christian Kalus, Uwe Griesinger, Rainer Pforr, Josef Mathuni, Guenther Ruhl, Wilhelm Maurer

Proceedings Volume 4000, (2000) https://doi.org/10.1117/12.388969

KEYWORDS: Photomasks, Quartz, Etching, Chromium, Phase shifts, Critical dimension metrology, Picosecond phenomena, Finite-difference time-domain method, Semiconducting wafers, Lithography

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Proceedings Article | 28 April 1999 Paper

FIRM: a new software tool for calibration of lithography simulation

Dietmar Krueger, Christian Kalus, Andreas Erdmann, Christoph Friedrich, Rainer Kaesmaier, Axel Feike

Proceedings Volume 3741, (1999) https://doi.org/10.1117/12.346888

KEYWORDS: Calibration, Matrices, Lithography, Algorithm development, Computer simulations, Optimization (mathematics), Chemically amplified resists, Mathematical modeling, Photoresist processing, 3D modeling

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Proceedings Article | 12 February 1997 Paper

On the way to 1 Gb: demonstration of e-beam proximity effect correction for mask making

Anja Rosenbusch, Christian Kalus, Hiroyuki Endo, Yasuki Kimura, Akihiro Endo

Proceedings Volume 3236, (1997) https://doi.org/10.1117/12.284027

KEYWORDS: Mask making, Raster graphics, Photomasks, Critical dimension metrology, Data corrections, Scattering, Electron beam lithography, Sun, Control systems, Data conversion

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The e-beam proximity effect is well known as one of the limiting factors in e-beam lithography. As features get smaller the need for e-beam proximity effect correction increases. There exist different approaches to cover these effects by varying dose or shape of the pattern layout during the exposure step. Whichever algorithm is used, the question of proximity effect correction gets more and more a performance problem for forefront applications like the 256 megabit and 1 gigabit chips. The correction approach has to handle large data volume in reasonable time. Key to overcome this hurdle is to include hierarchial data handling into the proximity correction algorithm, which involves hierarchical data structures as well as hierarchy reorganization methods. The goal of the present work is to perform all necessary steps in order to guarantee the accuracy of the exposure result for the 1 gigabit memory chip. One step of the preparation is the e-beam proximity correction for raster scan machines. With respect to proximity effect correction, raster scan machines have a severe drawback. The scanning speed is constant while writing the layout, i.e., dose variation is not applicable to compensate for the proximity effect. There is, however, the geometry which can be exploited as degree of freedom. Geometrical variations of the layout underlie many constraints such as neighboring features, the exposure grid of the e-beam tool and, but not least, writing time. The paper presents how to solve some of the major problems occurring when proximity effect correction becomes an unavoidable step in the mask making process. Power and application limits of proximity effect correction for raster scan machines are investigated. The exposure has been carried out on a MEBES 4500 system. Process latitude and line width linearity are presented. In addition, practical questions like file size increase due to proximity correction are investigated. Exposure results of uncorrected and corrected pattern are compared to demonstrate the necessity of the correction as well as the improvement in pattern fidelity.

Proceedings Article | 27 May 1996 Paper

Hierarchical e-beam proximity correction in mask making

Ulrich Hofmann, Christian Kalus, Anja Rosenbusch, Rik Jonckheere, Andrew Hourd

Proceedings Volume 2723, (1996) https://doi.org/10.1117/12.240465

KEYWORDS: Photomasks, Mask making, Optical proximity correction, Computer aided design, Raster graphics, Wafer-level optics, Reticles, Scattering, Optical calibration, Fractal analysis

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Proceedings Article | 8 December 1995 Paper

Hierarchical proximity correction using CAPROX

Ulrich Hofmann, Christian Kalus, Anja Rosenbusch, Hiroyuki Endo, Yasuki Kimura, Akihiro Endo

Proceedings Volume 2621, (1995) https://doi.org/10.1117/12.228210

KEYWORDS: Scattering, Optical proximity correction, Electrons, Algorithm development, Data processing, Computer aided design, Optical spheres, Electron beam lithography, Scanning electron microscopy, Data corrections

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Showing 5 of 18 publications

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