Abstract
A treelike hybrid multi-cluster tool is composed of both single-arm and dual-arm cluster tools with a treelike topology. Scheduling such a tool is challenging. For a hybrid treelike multi-cluster tool whose bottleneck individual tool is process-bound, this work aims at finding its optimal one-wafer cyclic schedule. It is modeled with Petri nets such that a onewafer cyclic schedule is parameterized as its robots’ waiting time. Based on the model, this work proves the existence of its onewafer cyclic schedule that features with the ease of industrial implementation. Then, computationally efficient algorithms are proposed to find the minimal cycle time and optimal onewafer cyclic schedule. Multi-cluster tool examples are given to illustrate the proposed approach. The use of the found schedules enables industrial multi-cluster tools to operate with their highest productivity.
Highlights
A cluster tool in wafer fabrication integrates a robot, two loadlocks, and a few process modules
OSLB One-wafer cyclic schedule with the lower bound of cycle time
Bai et al [33] present a method to optimize the configuration of buffer capacity such that a one-wafer cyclic schedule with the lower bound of cycle time can be found for multi-cluster tools
Summary
A cluster tool in wafer fabrication integrates a robot, two loadlocks, and a few process modules. [26], [27] propose a method with polynomial complexity to find an optimal cyclic schedule for both single-arm 2cluster tools and a treelike M -cluster tool. Their method can successfully find a multi-wafer cyclic schedule, i.e., more than one wafer is produced in each period [11]. For a process-dominant single-arm multi-cluster tool with a linear topology, an optimal one-wafer cyclic schedule (O2CS) can be always found by an efficient method [29]. Bai et al [33] present a method to optimize the configuration of buffer capacity such that a one-wafer cyclic schedule with the lower bound of cycle time can be found for multi-cluster tools.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
