Study of stress to Solder Joint by Underfill filling

摘要

To investigate how the underfill of a device produced by flip chip bonding affects the chip's reliability, the Young's modulus distribution in the underfill's in-plane and thickness directions was measured at many micro regions throughout the material using a nanoindentation measuring method. The results showed that the underfill's nonhomogeneity can occur depending on the filling location and/or dispensing direction. The causes of this nonhomogeneity and stress distribution on the solder bump was analyzed using a finite difference method, finite element method and Piezoresistance test chips, and the effect of the underfill on the solder bump was studied.