Characterization and FE analysis on the shear test of electronic materials

Adhesion is one of the main reliability concerns in electronic packages. However, the lack of standards to characterize this property makes it difficult to interpret the results. In this work, a series of shear tests have been conducted to evaluate adhesion strength of different electronic materials. Finite element analysis (FEA) is employed here to model the shear strength of microelectronic materials and to analyze the stress distribution in the specimen and substrate in order to understand this failure mechanism. The shear tool force and displacement at failure were measured experimentally and used as boundary condition for the FEA calculations. Several combinations of soft and stiff materials for specimens and substrates respectively have been evaluated in order to estimate the effects on the shear strength. The general trend from experimental and FEM results shows that soft specimens present a high concentration of stresses in the loaded surface while in the case of rigid specimens, the stresses are distributed in the whole area of contact between specimen and substrate. A proposal for calculating the shear strength was done. (C) 2004 Elsevier Ltd. All rights reserved.