Cohesive and Interfacial Fractures in Particulate Polymer Composites: Reflow-induced Filler Densification and Epoxy-Filler Adhesion Loss

Heterogeneous viscoelastic materials such as silica or silver particle-filled epoxy glues are important adhesives in the semiconductor and electronics industries. Systems requiring both materials adjacent to each other to satisfy conductive and insulative package requirements are rare, and studies on their compatibility, thermomechanical behavior and reliability are scarce. Herein, we report the analysis of the cohesive and interfacial fracture observed in such systems subjected to mechanical stress, after varying assembly conditions. Filler densification in the conductive glue resulting in an early fail as compared with the non-conductive glue, manifested as an open failure in the simultaneous electrical and mechanical test