Since the stress and displacement fields near a bonding edge show singularity behaviors, the adhesive strength evaluation method, using maximum stresses calculated by a numerical stress analysis such as the finite element method, is generally not valid. In this paper, a new method, which uses two stress singularity parameters, is presented for evaluating adhesive strength. This method is applied to several kinds of molded models, composed of epoxy base resin and Fe-Ni alloy sheets, and plastic encapsulated LSI models. Predictions about the initiation and extension of delamination are compared with the results of observations made by scanning acoustic tomography on these models.

An energy dispersive diffraction X-ray spectrometer with a sub-micron X-ray beam is developed to analyze crystalline structures in micro-regions of ULSIs. It is used to analyze strain in fine Al interconnections. The strain (ε) in lines with Al single-layer structures showed a dependence on the line width (W)=ε -0.8 at W below 1.5 µ m. The origin of these strains is mainly intrinsic stress in Al films and thermal stress caused by differences in the coefficients of thermal expansion between Al and Si. Introducing barrier metals reduces the dependence of strain in an Al layer on the line width.

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