Optimal One-Wafer Cyclic Scheduling of Single-Arm Multicluster Tools With Two-Space Buffering Modules

Abstract

A multi-cluster tool is composed of a number of individual cluster tools linked by buffering modules (BMs). The capacity of a BM can be one or two. Aiming at finding an optimal one-wafer cyclic schedule, this paper explores the effect of twospace BMs on the performance of a multi-cluster tool. A Petri net (PN) model is developed to model it by extending resourceoriented PNs. The dynamic behavior of robot waiting and tasks, process modules, and buffers is well described by the model. This paper shows that there is always a one-wafer cyclic schedule that reaches the lower bound of the cycle time of a process-bound tool. Furthermore, a closed-form algorithm is revealed to find such a schedule for the first time for such multi-cluster tools. Illustrative examples are given to show the application and power of the proposed method.Index Terms-Multi-cluster tools, Petri net (PN), scheduling, semiconductor manufacturing.

Scheduling twin-cluster tools for complete concurrent processing with wafer residence time constraints

“…Zhu et al [11] developed a Petri net model of a single-arm multi-cluster tool and proposed a condition for the existence of cycle scheduling. Based on [11], Yang et al [12] investigated a single-arm multi-cluster tool with two BMs and proposed a closed-loop algorithm to find a cycle scheduling plan. Dual-armed twin-cluster tools.…”