Finite element analysis of thermal stress in Through-Silicon Via structure

Through-Silicon Via (TSV) is a key technology for 3D interconnection of ICs. Mismatch in the properties of constituent materials causes significant amount of stress in the TSV structure during thermal loading. Such thermal stress is one of the key issues for the reliability of electronic packaging. In this work, the thermo-mechanical stress in a TSV structure is investigated in detail using the finite element method. A metal (Cu) and two carbon nanotube (CNT) based composites, (CNT-Cu and CNT-epoxy) are analysed as filler material in TSV. CNT based composites produce lower amount of stress in the structure in compare to the metal filler. The effect of metal (Cu) pad on the stress distribution in TSV is also investigated in this work. Cu pad has significant influence on the stress distribution and CNT-epoxy exhibits better thermo-mechanical performance over the other two fillers in both cases of TSV structure with and without Cu pad. The obtained results should have potential to find a better alternate of conventional Cu via ensuring thermo-mechanical reliability in TSV.