Parametric Studies of Effects of Solder Bump Pitch, Package Size, and Molding Compound and Substrate Thicknesses on Warpage of PBGA Packages

Abstract

Plastic ball grid array (PBGA) is one of the most widely used types of chip packages in various electronic devices such as network servers, microcontrollers, and memory devices. As the demand for higher performance electronic devices grows, the I/O densities of PBGA packages are increasing while requiring superior reliability. Warpage induced during the reflow assembly process is one of the crucial factors affecting the thermo-mechanical reliability of PBGA packages; therefore, accurate warpage prediction is an important task for package design processes. In this study, the effects of four geometric factors (the solder bump pitch, package size, and molding compound and substrate thicknesses) of the PBGA package on its warpage are assessed by using parametric finite element analysis. The correlation between PBGA warpage and the four factors is studied using the regression method. These results are expected to provide design guidelines for in-house PBGA designers.