Die Attach Failure Modes Analysis and Process Optimization for Mass Production Yield Improvement of MicroSD Card COB Packaging

Affected by the trend of terminal electronic products to be thin, light and short, the packaging of MicroSD cards also tends to be thinner and thinner. The packaging yield of such products has always been a challenge faced by packaging companies. The COB type Micro SD produced by Guangxi Kelin Semiconductor Company is taken as the target research object, and the die attach process that causes the loss of packaging yield is studied. We first investigate the main failure modes in the die attach process and conduct a preliminary analysis of the failure causes. Then a DOE experiment is designed to reduce defects. We design a full factorial experiment with four factors, two levels, and three center points. The factor significance analysis of the experimental results shows that the model is curved. Then the response surface method is used to find the main factors affecting the defects, analyze the main effects and interaction effects of the factors, and optimize the model to find the optimal process parameter settings. Finally, a confirmation run with mass production is carried out, and the packaging yield is increased by 2.56%, and the overall yield is increased to 99%. The method used in this paper will serve as a reference for improving the COB type die attach process and improving the yield.