ThinFilmInterfacial Strength Characterization UsingMixedModeBending

Nowadays, oneofthetrends ofmicroelectronic packaging istointegrate multiple functional systems into onepackage, resulting inmoreapplications ofmulti-materials intheform oflaminated thinfilms orstacks. As a consequence, the numberofinterfaces increases. Thiscauses tremendous mechanical problems, forinstance interfacial delamination. Prediction ofinterface delamination istypically doneusing thecritical energy release rate. However, interface strength is highly dependent onmodemixity. A newtestsetupis designed formixedmodebending testing. Itallows for measuring thestable crack growth asthefunction ofmode mixity. Thecracklength, necessary forcalculation ofthe energy release rateismeasured byoptical microscope and evaluated bypattern recognition software. Comparing finite element result withcritical energy release rate, itcould be predicted whether andwhenthecrack attheinterface will propagate. Themodemixity isdetermined through combining experimental data withFEM simulation data.