Warpage Simulation Including Effect of Process and MC Curing Shrinkage

Abstract

As panel size becomes bigger and bigger and the panel warpage issue during processing is more a concern. In this paper, finite element method is used to simulate and study the panel warpage at room temperature for a WLCSP package. Major warpage contribution process steps are included in the simulation, which are panel molding and curing. Mold compound's cure shrinkage value is tested and included in the simulation. The warpage caused by mold compound's curing shrinkage and thermal shrinkage are simulated separately. The mold compound's modulus changes during curing and post molding are also considered in the simulation. The simulated panel warpage has a good correlation with test result. New design is proposed by simulation to control the panel warpage. Design changes are based on simulation and design constrains. The panel warpage is controlled within process requirement. The good correlation between simulation and test shows the feasibility of the panel warpage simulation method and procedures proposed in this paper.