The Dependence of Moisture Induced Die Stresses Upon Moisture Properties of Polymer Materials in Electronic Packages

Polymer materials have been widely used in electronic packaging with many advantages such as: lower cost, light weight and good performance. They however suffer a major drawback that results in a number of challenges for reliability engineers and researchers, in which polymer materials are quite sensitive to moisture absorption when exposed to humid environment, causing many failure modes in electronic packages such as: popcorn cracking, delamination or corrosion. It is well-known that finite element simulation is a powerful tool to evaluate the effects of moisture on electronic package reliability. In this study, three moisture properties (diffusivity, saturated concentration, and coefficient of moisture expansion) were experimentally characterized. The obtained results were then used to perform moisture diffusion simulations on various types of electronic package. Finally, a numerical study was conducted on the dependence of the moisture effects (weight gains, die stresses) upon each moisture property of polymeric components of three kinds of electronic packages (Quad Flat Package, Plastic Ball Grid Array, and Flip Chip on Laminate). The results of the study provided valuable insights into how moisture induced die stresses vary with each moisture property of polymeric components in the packages.