Simulation based correlation analysis on performance issues of semiconductor wafer fabrication facilities

There are many performance issues concerned in a semiconductor wafer fabrication facility (fab), such as move, queue length, utility, cycle time, throughput and on-time delivery rate. However, it is difficult to demonstrate their relations to each other. In this paper, the correlation coefficient method is utilized to analyze their relations from plentiful simulation results and obtain some meaningful conclusions. Firstly, these performance issues are classified into three categories, i.e., machine related, fab-wide related and job related ones. Secondly, a mass of simulation data related to performance issues are obtained with a variety of simulations with different workload levels (under-loading, heavy-loading and over-loading) and decision criterions (FIFO, EDD, SPT, LS and CR). Thirdly, correlation coefficient method is used to identify the correlations among these performance issues from simulation data. Finally, we obtain a performance system of fabs.