Steps to prevent quality and reliability issues resulted from design optimization for productivity improvement

摘要

Productivity improvement in manufacturing is always the key focus to strengthen an enterprise cost position to stay ahead of competition. In semiconductor manufacturing, improve the cost position through faster machine speed, reduce man to machine ratio, utilization of material efficiently, increase the through put per fix process cycle, and etc. are the common practices. In this paper, cost improvement is achieved through maximizing the number of packages per fix dimension of leadFrame (LF) and with minimum investment. The unit density per area of the LF has increased by 60% mainly through the introduction of through-gate design and increased number of rows per LF by 30%. However, the introduction of these measures have also increased the complexity of all the processes to manufacture the SSO8 package. The main focus of this study is on molding process. Upfront steps are taken to optimize the design so that unwanted quality and reliability issues during qualification and ramp-up phase can be eliminated. With the through gate design the compound flow mechanics and rheology that can create wire sweep, incomplete fill, and compound wettability are thoroughly examines and analyzed before the design is frozen. The upfront analysis on the technical challenges and numerical models are used to predict the interactions between material behavior and the tool designs. The results at qualification and ramp-up showed that molding related issues can be greatly minimized and project timeline can be met. Investment is minimized by designing the frame dimension to the existing machine maximum capacity except trim and form machine.