Do we still need daily production target setting in fully automated fabs?

Fab operations have evolved to full automation along with advancements of automation technologies in material handling, inspection and manufacturing execution and management. A school of practitioners and re-searchers have been arguing that there need only two levels in short-interval production control of a fully automated fab: wafer release (WR) on the top and real time dispatching in the bottom. They have also raised the question: Are the middle two levels of daily production target setting and machine allocation (DPTS&MA) traditionally designed for shop floor operators still necessary? In this paper, we take a first step to address the question by simulation and comparing the performance of the simplest automated dispatching policy, First-In-First-Out (FIFO), and the outperformed dispatching policy in [7], Fluctuation Smoothing Mean Cycle Time and Least Lot Slack-time(FSMCT+LLS), with a traditional DPTS&MA scheme under the same given WR. FIFO serves as a performance lower bound, FSMCT+LLS servers as the representative of good automated dispatching policies and DPTS&MA captures essence adopted by many practitioners of proportional target tracking and detailed dispatching of FIFO. Simulations are over a benchmarking mini-fab of six stages and five tool groups. Preliminary results show that DPTS&MA outperform FSMCT+LLS and FIFO in line balancing and cycle time performance for both high and low variability scenarios. We shall demonstrate how such a foundation may further be exploited to study if DPTS&MA is needed in the short-interval production control hierarchy of a fully automated fab.