Scheduling Single-Arm Multicluster Tools for Two-Type Wafers With Lower-Bound Cycle Time

Qing Hua Zhu, Geng Hong Wang, Nai Qi Wu, Yan Qiao, Yan Hou, Meng Chu Zhou, Si De Zhao

Research output: Contribution to journalArticlepeer-review


In today's semiconductor manufacturing industry, wafer foundries often face the challenge of producing a variety of integrated circuit chip products using a single manufacturing line. To address this, multicluster tools have become a popular choice for processing multiple wafer types simultaneously. Operating such tools involves coordinating the robots in adjacent individual tools to transport multitype wafers through a shared buffer. This study aims to develop a scheduling method for the concurrent fabrication processes of two wafer types, performed by a multicluster tool with wafer residency time constraints. The proposed approach presents a two-backward sequence, based on a backward strategy of a single wafer type, to convert a one-wafer cyclic schedule into a one-wafer-per-type cyclic schedule while revealing its temporal properties. To ensure a smooth operation of a single-arm multicluster tool system and synchronize multiple robots, several necessary and sufficient conditions are derived for the first time. Two efficient algorithms are then proposed to determine the feasibility of a periodic schedule and obtain a schedule that achieves the lower-bound cycle time under a two-backward strategy, maximizing the productivity of such a multicluster tool. Finally, numerical simulations and two practical examples are presented to demonstrate the applications and performance of the proposed approach.

Original languageEnglish (US)
Pages (from-to)6658-6671
Number of pages14
JournalIEEE Transactions on Systems, Man, and Cybernetics: Systems
Issue number11
StatePublished - Nov 1 2023

All Science Journal Classification (ASJC) codes

  • Software
  • Human-Computer Interaction
  • Electrical and Electronic Engineering
  • Control and Systems Engineering
  • Computer Science Applications


  • Multicluster tools
  • scheduling
  • semiconductor manufacturing
  • two wafer types


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