Experimental and numerical investigations on the durability and fracture mechanics of the bonded systems for microelectronics application

Water-assisted crack growth at an epoxy/glass interface was measured as a function of applied strain energy release rate, $G$, and temperature using a wedge test geometry. The specimens consist of two glass plates bonded with a thin layer of proprietary epoxy adhesive. The crack fronts along the epoxy/glass interfaces were measured using an optical stereomicroscope. The relationship between $G$ and the debonding rate, ν, can be measured using this method, and the threshold value of strain energy release rate, $Gth$, can be determined from the measured data. A preliminary model was developed based on the thermal activation barrier concept, and allows the prediction of $Gth$ for the temperatures beyond the testing region.; Changes in interfacial strain energy release rate caused by thermal residual stresses in a triple-layered specimen were analyzed in Chapter Three. The curvature of a bimaterial strip was chosen to characterize the residual stress in the specimen, and the strain energy release rate, caused by both tensile and compressive residual stresses in the adhesive, was derived for an asymmetric double cantilever beam (ADCB) geometry. The thermally induced energy release rate, $GT$, is found to be independent of crack length, but is a function of residual stress level and geometric and material parameters of the specimen.; The adhesion of films and coatings to rigid substrates is often measured using blister geometries, which are loaded either by an applied pressure or a central shaft. The measurement will be affected if there are residual stresses that make a contribution to the energy release rate. Both analytical solutions and numerical results reveal that uniform tensile residual stresses reduce a specimen's deflection if it experiences plate behavior under small loads. However, this effect diminishes when membrane behavior is dominant.; The mechanics of a single-lap joint with different boundary conditions subjected to tensile loading are investigated. Closed-form solutions are obtained for a specimen configuration considering different clamping methods. The solutions in this study suggest that different grip configurations mainly affect the response of the specimens if the grip position is close to the joint edge or the loads are small. Generally, the influence caused by different gripping methods is only limited to the boundary region, and the behavior of the joint part subjected to tensile loading is almost the same as that for a simply-supported case. (Abstract shortened by UMI.)...