Effect of temperature on stress-induced open failure in aluminum interconnects of LSIs

Abstract

The effect of temperature on stress-induced open failure in aluminum interconnects of LSIs is numerically analyzed. Calculation parameters are annealing and reliability test temperatures. Hexahedra meshes are used to calculate thermal stress, elastic strain, plastic strain and creep strain as a function of process temperature and time. Changes in the shape of the LSI chip during the process is taken into account. The three types of temperature dependence of the failure lifetime reported previously can be explained by using a kinetic model in which the change in stress with time due to the creep strain is considered. It is found that reducing annealing temperature increases the failure lifetime. However, the effect saturates below the aluminum film deposition temperature.