On Wire Failures in Microelectronic Packages

At present, over 95% of the manufactured packages are still being wire-bonded. Due to the ongoing trend of miniaturization, material changes, and cost reduction, wire-bond-related failures are becoming increasingly important. Different finite-element (FE) techniques are explored for their ability to describe the thermomechanical behavior of the wire embedded in the electronic package. The developed nonlinear and parametric FE models are able to predict the strong nonlinear behavior of wire failures and multifailure-mode interaction accurately and efficiently. It is found that both processing and reliability-testing environments as well as the occurrence of delamination strongly increase the risk of wire failures. Our results indicate that processing and reliability-testing influences are much less than those of the delamination. Combining the strengths of predictive modeling with simulation-based optimization methods, the optimal wire-loop shape is obtained.