Mixed mode bending test for interfacial adhesion in semiconductor applications

Currently, prediction of interface strength is typically done using the critical energy release rate. Interface strength, however, is heavily dependent on mode mixity. Accurately predicting delamination therefore requires a material model that includes the mode dependency of interface strength. A novel test setup is designed which allows mixed mode delamination testing. The setup is a stabilized version of the mixed mode bending test previously described by Reeder and Crews (1990; 1991). It allows for the measurement of stable crack growth over the full range of mode mixities, using a single specimen design. The crack length, necessary for calculation of the energy release rate, is obtained from an analytical model. Crack length and displacement data are used in a finite element model containing a crack tip to calculate the mode mixity