Advanced risk analysis of interface delamination in semiconductor packages: A novel experimental approach to calibrating cohesive zone elements for finite element modelling

摘要

Interfacial delamination in semiconductor packages during their lifetime is a reliability risk. For the realisation of a “Design for Reliability” approach, the whole product needs to be studied virtually using Finite Element (FE) simulations. Only this approach allows for the evaluation of possible failure mechanisms, which is an integral part of risk analyses in reliability assessments. The Cohesive Zone Method enables the prediction of interfacial damage initiation and damage evolution in the simulation model. For accurate simulation results, not only material models need to be chosen wisely, but also the parameters for the cohesive zone. A new experimental method was proposed for the calibration of these damage models, utilising the Advanced Button Shear Test. Critical fracture energies are determined based on sub-sequent shear loading, and thus, sub-critical damage evolution at the interface of the test vehicle. This paper describes a FE simulation model used for the verification of the calculated critical fracture energies. Influencing factors are identified using simulation and experiment, and a new calibration procedure is introduced. Furthermore, design adaptations of the shear chisel are given for the optimisation of the experimental procedure.