Adhesion and Subcritical Debonding of Polymer Interfaces for Microelectronic Packaging

Abstract

ABSTRACTTechniques are discussed for evaluating both critical interface adhesion values as well as the sub-critical debond behavior of polymer/silicon and polymer/polymer interfaces. Sub-critical debonding behavior is expected to be most relevant in predicting the in-service lifetime of microelectronic packages. Our research characterizes the debonding of a benzocyclobutene overlayer, as well as a technologically relevant epoxy underfill/polyimide/silicon interface system. Adhesion values are measured in a double cantilevered beam (DCB) and four-point bend fracture mechanics geometries by driving a stable debond along the relevant interfaces. The effect of temperature on subcritical debonding in an underfill/polyimide interface is described. Issues of crack path selection involving the selection of microstructurally weak paths in the layered system are considered.