D. Meng, J. Rupley, C. McMahon, LSI, Fort Collins, CO

Summary: Cu is being evaluated as an alternative to conventional Au as wire bonding material in recent years mainly because of its potential for significant cost reduction (up to 90%)1. Additionally Cu wire boning has better electrical, thermal and mechanical performance over Au wire bonding. However, a package with Cu wire bonding brings unique reliability issues for the package as well as challenges for failure analysis. A primary challenge for the failure analysis is the process to decapsulate a device with Cu wire bonding. In is paper, we will present our decapsulation solutions including wet chemical etch, plasma etch, laser ablation and the combination of these techniques.In a summary, Cu wire bonding package could be decapsulted using wet chemical etching with a good quality with well controlled etching time and temperature. Further, the plasma etching for Cu wire bonding package could be shorted to less than one hour by using laser ablation removing most of encapsulant mold compound.