Process-induced Warpage in HVQFN Package: Effect of Design Parameters and Processing Conditions

QFN package is getting rapid market acceptance because of its excellent thermal and electrical performance and its miniaturization and low cost. However, the warpage problem caused by molding process imposes a great concern for the manufacturing of the products. To investigate the effect of the EMC properties, package parameters and processing conditions on the warpage, experimental approach and numerical simulations were conducted on Philips business carrier HVQFN package. A series of molding experiments for QFN matrix strips with the model-molding compounds were performed. In the molding experiments, different processing parameters, filler loading and die thickness were used. The warpage was measured by a contact probe coordinate measuring system. In the finite simulations, a previously proposed cure-dependent constitutive model for the encapsulating EMC was applied to describe the behavior of the material during the curing process. The results show that both of the filler percentage and the die thickness has a significant effect on the final warpage level.