A modified button-shear method for measuring fracture toughness of polymer-metal interfaces in IC packages

Abstract

Many failures in plastic IC packages involve delamination. Fracture mechanics has been applied to study such failures. However, in order to be able to predict delaminations, the adhesion strength or more specifically the fracture toughness of the particular interface needs to be measured as a function of temperature, moisture content and mode mixity. Several methods have been described in the literature but most of them are too complex for wide implementation by industry. In this paper, a new and relatively easy method for measuring the fracture toughness of a polymer-metal interface is presented. It is a modification of the widely-used button shear test. The same equipment can be employed although the specimens needs to be modified. It is shown that a range of mode mixity can be obtained by varying the shearing height.