Effects of molding compounds on warpage and damage of PBGA after post mold cure

In the present study, governing damage mechanisms after post mold cure (PMC) for plastic ball grid array (PBGA) packages have been evaluated by a three-dimensional (3-D) thermo-viscoelastic finite element method. The parametric studies for the PBGA package with various molding compounds have been performed. A wide range of the modulus (1 MPa~15 GPa) and the coefficient of thermal expansion (CTE) (10 ppm~300 ppm) is evaluated to see feasibility of a new class of material set in the molding compound. Effects of thermo-mechanical properties of selected molding compound on the warpage and residual stress of the PBGA package are analyzed. Classification of modes of deformation in the BGA package with material sets will shed light on novel material development for better reliability. In addition, the optimum thermo-mechanical properties of molding compounds will be selected based on the parametric studies.