Measurement and Simulation of Thermal-Induced Stress in C2W 3D Integration with Template Alignment

Abstract

This paper presents the experimental and theoretical investigation of the thermal stress development in the C2W 3D integration with template alignment and the impact of fabrication parameters on the thermal stress. The experimental approach is accompanied with an optical profilometer, while the theoretical study is based on COMSOL FEM analysis. It is found that the thermal stress is primarily induced in the polymer hard curing process, and is accumulated within the cooling process due to the mismatch of coefficients of thermal expansion (CTE) with substrate. The thermal stress highly depends on the polymer thickness and the treatment temperature, and could be partially released by polymer etching. The measurement and simulation results indicate that the template alignment technology is compatible with semiconductor fabrication by optimizing the fabrication parameters. The feasibility of C2W 3D integration with template alignment is furthered demonstrated.