Cycle time estimation for semiconductor final testing processes with Weibull-distributed waiting time

Abstract

Accurate cycle time is an essential planning basis required for many production applications, especially on due date commitments, performance metrics analysing, capacity planning, and scheduling. The re-entrant final testing process is the final stage of the complicated semiconductor manufacturing process. To enhance the ability of quick responses and to achieve better on-time delivery in final testing factories, it is essential to develop an accurate cycle time estimation method. In this paper, we provide a statistical approach to calculate the cycle time for multi-layer semiconductor final testing involving the sum of multiple Weibull-distributed waiting times. In addition, percentiles of the cycle time are obtained which are useful to industrial practitioners for due date commitments satisfying the targeted on-time delivery rate. To demonstrate the applicability of the proposed cycle time estimation model, a real example in a semiconductor final testing factory which is located on the Science-based Industrial Park in Hsinchu, Taiwan, is presented.

Keywords:

• cycle time estimation
• semiconductor final testing
• Weibull distribution