Thermodynamic analysis of SiO2 thickness's effect on TSV

摘要

Through Silicon Via (TSV), a multi-layer structure of Cu/Ta/SiO₂/Si, is one of the most important structure in three dimension integrated circuits (3D ICs). Because of the great difference of coefficient thermal expansions (CTEs) between different meterails, TSV has a higher level of thermal stress that may lead to serious thermal-mechanical problems. Here, a thermodynamic analysis is carried out using finite element method to determine the effects of thickness of SiO₂ layer on the distribution of thermal stress. COMSOL, a finite element software, is used to realize the modelling. Through simulation and analysis, it is clarified that the maximum stress appears at SiO₂ layer. With the increase of the SiO₂ layer thickness, the stress increases synchronously. And the area that has higher stress expands in the meanwhile. This research provides a way for thermodynamic analysis using finite element method, which can determine the regular of stress distribution with a specified SiO₂ layer thickness.