Passivation cracking analyses of Micro-structures of IC packages

The passivation cracking of Micro-structures of IC packages is studied by maximum principal stress theory using a certain 2D FEM model with different design parameters, pitch of lines, width of line, thickness of epoxy, thickness of dielectric layer, thickness of glue, the glue material's yielding stress and Aluminium yielding stress (following as "d", "w", "t_epo", "t_Teos", "t-glue" "sy_glue" and "sy_al" respectively). For different critical process steps, the final process temperature is acted as a representative parameter to analyze its impact. Furthermore, Response Surface Model (RSM) of principal stress is established using any two design parameters. Results show that "d", "w", "t_epo", "sy_glue" and "sy_al" will have great influence on passivation cracking while "t_Teos" have a little impact.