A Theoretical Study on the Global Analysis of New Multimodal Optical Metrology for Critical Dimension (CD) Measurement and Stress Analysis in Advanced Semiconductor Packaging
Journal
2024 19th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)
Part Of
Proceedings of Technical Papers - International Microsystems, Packaging, Assembly, and Circuits Technology Conference, IMPACT
Start Page
378
End Page
381
Date Issued
2024-10-22
Author(s)
Abstract
This study focuses on simulating and theoretically analyzing a multimodal approach to new optical metrology, utilizing Finite Difference Time Domain (FDTD) and Finite Element Modeling (FEM) to determine the critical dimension (CD) and thermo-mechanical stress of high aspect ratio through silicon via (TSV) components. Global parameter sensitivity analysis is crucial for optimizing the metrology methodology and the optical measurement system. The proposed system methodology can measure CDs and stress, enabling real-time, in-line monitoring and control essential for maintaining high yields in semiconductor manufacturing. Deep ultraviolet (DUV) scatterometry measures high aspect ratio TSV CDs, as DUV light penetrates TSV structures. The FDTD simulation and global sensitivity analysis evaluate optical response variations due to Depth, TCD, BCD, and Spacing changes. Optimizing the illumination settings enhances the accuracy of sensitivity analysis. Depth is higher sensitive, and Spacing is lower sensitive. The higher tilt angle of 20° of illumination settings makes TCD, BCD, and Spacing more sensitive. Besides, mechanical stress in fine-pitch packaging deforms TSV structures, causing defects and device failure. This study uses 3D FEM to analyze stress tensors around copper-filled TSVs, ensuring reliable thermal stress determination. The overall stress distribution within the sample varies from -200 MPa to 800 MPa. A correlation is observed between the stress in silicon and the Raman frequency shift, which ranges from -4.5 cm-1 to 2.5 cm-1 and is associated with the inelastic scattering of incident electromagnetic waves. This multimodal approach advances the system for inline stress and CD metrology.
Event(s)
19th International Microsystems, Packaging, Assembly and Circuits Technology Conference, IMPACT 2024, Taipei, 22 October 2024 through 25 October 2024. Code 205827
Subjects
Critical Dimension
FDTD
FEM
Multimodal Optical Metrology
Raman Shift
Sensitivity analysis
Publisher
IEEE
Type
conference paper