Study on Effect of Annealing Process on Thermo-Mechanical Reliability of Cu Through Silicon Via (TSV) Structure

In this paper, a finite element analysis method was used to study the influence of annealing process on the thermo-mechanical reliability of Cu through-silicon via structure. Firstly, the processing technology of TSV structure with polyimide (PI) dielectric layer was introduced. Then, Von Mises stress distribution and Cu protrusion height of TSV structure, which used PI and SiO₂ as the dielectric layer respectively, were compared under 400℃ for 30 min. On this basis, the parameters of PI-TSV were analyzed further, including size parameters of TSV(the thickness of dielectric layer and TSV diameter, height, pitch) and annealing process parameters (annealing temperature and time). The results show that, compared with SiO₂-TSV, PI-TSV structure possesses better thermo-mechanical reliability after annealing, and it is an effective method for the Cu protrusion height and thermal stress reduction to appropriately increase the thickness of PI dielectric layer.