柱形铜凸点在热力耦合场中的原子迁移

With further miniaturization and harsh service loading, the failure problems of atomic migration for solder joints become more dominative in integrated circuit (IC) packaging. The temperature difference caused by thermal properties and electrical resistivity among different materials is a vital factor for IC package solder joints. In consideration of such a new lip-chip interconnect form as a Cu-pillar bump, thermo-migration and stress-migration of Cu-pillar bumps in thermomechanical coupling fields were investigated via the kinetic theory and viscoplastic mechanical analysis by means of finite element method. Informed of influencing factors of atomic migration, we obtained such parameters as temperature gradient and stress distribution in a specific model under temperature load, and then concluded the failure mechanism and occurrence conditions of atomic migration in multi-field coupling. The established failure models of atomic migration in the paper are expected to help improving the reliability in IC packaging.