Optimization of Gel and EMC for Micro Opto Coupler to Prevent Neck Crack of Gold Wire

摘要

This paper focuses on improvement and prevention of gold wire neck crack for a micro Opto coupler. This is a common industry problem, which often induce quality and reliability issues. The DOE simulations which include different thickness of gel, different Young's modulus and CTE of both gel and EMC are considered. TMCL simulation through FE code Ansys~® is conducted to evaluate the influence of various factors to neck crack of gold bond wire. As it is known, the fatigue property of gold wire is governed by the maximum plastic strain. So in simulations, the maximum plastic strain is mainly focused on to reflect the influence of concerned factors for avoiding gold bond wire crack. Several factors are optimized and the best choice for these items is screened out to prevent neck crack of gold bond wire. The suggestions to improve the product quality and reliability are presented based on the optimization of simulation results.