How to fabricate specimens for silicon-to-molding compound interface adhesion measurements

Abstract

We present a new method to fabricate specimen for interfacial fracture testing. It regards the interface between silicon die and epoxy molding compound (EMC). The crucial element of evaluating interfacial fracture strength is the calculation of critical fracture values. Such values can be obtained analyzing a bimaterial type of sample and by specifically inducing a delamination while monitoring conditions and loads. We use a sandwich type of sample where the epoxy molding compound encloses the silicon die. We give a detailed description of molding specimens using an established transfer molding process that has a sufficiently large cavity available. In order to prevent breakage and related residual stresses we use specific bearings to hold the silicon stripes symmetrically in place. The bearings are made out of cured EMC themselves. The samples did not break and allow for interfacial fracture characterization. For testing the specimens we used the Mixed Mode Chisel (MMC) setup, which is one of the first to at all induce and monitor delamination of the Si-EMC interface.