On the development of a modified button shear specimen to characterize the mixed mode delamination toughness

The electronic packages consist of various different materials like molding compound, leadframes and silicon. Due to thermal cycles, the CTE-mismatch of the used materials can lead to interfacial cracking between the layers. The delamination propagation strongly depends on the proportion of tension and shear loading (so called mode mixity) at crack vicinity.This study focuses on cracking of the molding compound/metal interface. A 'Low-Cost' test process is presented in this paper. This process permits obtaining various mixed mode ratios at crack tip with a single specimen. Tests are performed and the results are correlated with FEM simulation to determine the delamination toughness of molding compounds/metal interface under various mixed-mode loading conditions.