Pattern shift is one of the main failures of micro-electronics. In this paper, the influence of plastic deformation values of micro-structures of IC packages on the pattern shift of metal lines is studied by maximum plastic strain theory using a certain 2D FEM model with different design parameters, “d”, “w”, “t_epo”, “t_Teos”, “t_glue” “sy_glue” and “sy_al”. For different critical process step, the final process temperature is acted as a representative parameter to analyze its impact. Furthermore, Response Surface Model (RSM) of plastic strains is established using any two design parameters. Results show that “w”, “t_epo”, “t_Teos”, “t_glue” “sy_glue” and “sy_al” will have different influence on pattern shifting while “d” have little impact.