Driven by the growth trend of portable electronic products, the integration of functions into smaller electronic components (semiconductors) becomes more important, such as advanced packing. The fan-out type is the fastest growing advanced packaging platform. Re-Distribution Layers (RDL) are mainly structures in which the wafer lines are redistributed. In the process of RDL the residual film thickness in nanometers after Chemical-Mechanical Planarization (CMP) step and the depth of RDL structure are mainly the parameters should be measured to ensure the yield rate. In this research, we demonstrate an optical system design of microscope type spectral reflectometry which is based on finite microscope system with reflective objective. The advantage of finite microscope system is less optical components, which leads to less UV and NIR attenuation for the purpose of thin film (~5 nm) and thick film (~100 μm) measurement. Adjustable illumination angle design is also included. The illumination light incident on the sample are designed as parallel as possible for increasing the reflective light rays from bottom of RDL. The spot size of measurement area is ~13 μm in diameter. Meanwhile, the corresponding algorithm including thin film interference model fitting and Discrete Fourier Transform (DFT) for high density RDL analysis are presented. Our non-destructive solution can measure thin film as thin as 5 nm and the depth of high density RDL with line width/ space = 1 μm/ 1μm. Metrology results from RDL structure and SiO2/Si standard reference material are presented.
Through Silicon Via (TSV) interconnect technology have been used to serve a wide range of Three Dimensional
Integrated Circuit (3D-IC) production for higher integration and higher frequency purposes. Therefore, the inspection of
depth and Critical Dimension (CD) of TSV becomes a key issue for yield rate evaluation. In this research, we
demonstrate an optical system design of microscope type spectral reflectometry which is based on finite microscope
system. The advantage of finite microscope system is less optical components, which leads to less UV and NIR
attenuation for the purpose of thin film (~50 nm) and thick film (~50 μm) measurement. The illumination light incident
on the sample are designed as parallel as possible for increasing the reflective light rays from bottom of TSV. The spot
size of measurement area is 30 μm in diameter. Meanwhile, the corresponding algorithm including thin film interference
model fitting and Discrete Fourier Transform (DFT) for high aspect ratio TSV analysis are presented. The thickness of
oxide film and the depth of TSV can be calculated simultaneously. Our non-destructive solution can measure TSV
opening diameter as small as 5 μm and aspect ratio greater than 15:1. The measurement precision is in the range of 0.03
μm. We also evaluate the total measurement uncertainty which is around 0.22 μm. Metrology results from actual TSV
wafers are presented. The SEM results were made as comparison.
We propose a novel multi-channel liquid crystal cell parameter measurement system, which combines the spectroscopic
ellipsometry technique with the hyperspectral imaging spectrograph for the multi-point measurement. This system is
based on PSA setup (polarizer-sample-analyzer) to measure normalized transmission spectrum for analyzing properties
of homogeneous cell and MVA cell. We also develop a theoretical method to simplify the calculation of the orientation
angle of liquid crystal cells for speeding up the measurement. The liquid crystal cell gap can be calculated by the
measured retardation and the given refractive indices of specified wavelength. The pretilt angle is also analyzed by
multi-channel measurement system. We present the analysis of hyperspectral imaging spectrograph and the orientation
angle measurement by direct calculation method for high speed on-line multi-channel liquid crystal cell parameter
measurement.
It is very important to generate high-speed optical synchronization signal for high speed computer. The rational harmonic (RH) modelocking scheme is a useful technology to generate pulses at a repetition rate higher than the modulation frequency. Such a technique can vary the clock rate of the synchronous optical signal in future high speed computer backplane for optical clock distribution. In this paper, we demonstrate an variable RH active modelocking light signal technique using a figure eight fiber cavity (F8C) incorporating a nonlinear amplifier loop mirror (NALM) using phase modulator to generate high repetition rate optical pulses above 10 GHz.
We purpose a new design configuration of a phase modulated mode-locked figure eight laser(F8L)with two EDFAs and experimentally measure its characteristics in this paper. Our designed F8L mode-locked laser concludes two EFDAs, an isolator, a phase modulator(PM), two polarization controllers(PC)and two unbalance couplers(90:10). Two
PCs are put at the input and output of two EDFAs to fix the polarization of light to generate a stable mode-locking laser
output. A nonlinear loop mirror(NLM) is used to make the pulse being compressed. The PM can add an RF modulation signal to help mode-locking of the ultrashort pulse. Preliminary experimental demonstration is given in this paper. We present the time relative responses of this system for high speed photography triggering.
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