A novel method of computing the Stess intensity factors of the interfacial cracks

Bi-material interface and multi-layer systems are widely observed in modern microelectronic applications. When the external load reaches a critical level, the crack either extends along the interface or kinks out of the interface, and finally leads to the catastrophic failure. In fracture mechanics, stress intensity factor, mode mix ratio and strain energy release rate are normally used as parameters to evaluate the adhesive toughness and failure prediction of bi-material interfaces. In this research, a new efficient method based on the finite elements and the extended proportional method using nodal-displacement behind the crack tip was introduced to obtain the stress intensity factors, then the strain energy release rate could be computed by using its relationship with the stress intensity factors. The robustness and accuracy of the current proposed method was discussed by comparing the solution results proposed by other researchers. It was found that the average error is less than 1% for the stress intensity factors, and it can get accurate results with rather coarse finite element meshes. Furthermore, the current method is fairly efficient and less computational resource consuming. The current method could be used as an effective tool in the reliability analysis of the bonded multi-layers in microelectronics.