Study on thermal stress and keep-out zone induced by Cu and SiO₂ filled coaxial-annular through-silicon via

Abstract

Coaxial-annular through-silicon via (CA-TSV) is a novel TSV structure. In this letter, the thermal stress and keep-out zone (KOZ) of Cu and SiO₂ filled CA-TSV are studied, considering anisotropic property of silicon. Firstly, by employing ANSYS software, the CA-TSV-induced thermal stress is simulated and analyzed. Secondly, by evaluating the effects of thermal stress on carrier mobilities of pMOS and nMOS channels, the KOZs induced by CA-TSV is estimated and compared with those of coaxial TSV (C-TSV), for the cases of transistor channels along [100] and [110] orientations. It is proved quantitatively that CA-TSV has better thermo-mechanical performance than C-TSV.