Multiobjective lot scheduling and dynamic OHT routing in a 300-mm wafer fab

Jia Wei Yang*, Hsueh Chien Cheng, Tsung Che Chiang, Li Chen Fu

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

19 Citations (Scopus)


In this paper, we solve two problems in a 300-mm wafer fabrication facility (fab). Firstly, for the lot scheduling problem, we propose a multi-objective genetic programming based rule generator (MOGPRG) to evolve useful dispatching rules, which can provide near-optimal lot schedules concerning multiple objectives. Secondly, the overhead hoist transports (OHT) routing problem is considered. As the modern automated material handling system (AMHS) is capable of doing toolto-tool direct delivery, the congestion of OHTs may happen more often than the past. To deal with the traffic congestion in AMHS, a dynamic routing method is proposed to find the nearshortest and less-congested path for the OHT to travel along. It can reduce the traffic congestion and achieve fast lot delivery by adapting to the dynamic traffic environment. The proposed MOGPRG is integrated with the dynamic routing method to improve two fab performance metrics: mean cycle time and tardy rate. Experimental results show the effectiveness of the proposed MOGPRG and dynamic routing method.

Original languageEnglish
Article number4811517
Pages (from-to)1608-1613
Number of pages6
JournalConference Proceedings - IEEE International Conference on Systems, Man and Cybernetics
Publication statusPublished - 2008
Externally publishedYes
Event2008 IEEE International Conference on Systems, Man and Cybernetics, SMC 2008 - Singapore, Singapore
Duration: 2008 Oct 122008 Oct 15


  • Dispatching rules
  • Genetic programming
  • Multiobjective evolutionary algorithm
  • Overhead hoist transport (OHT) routing
  • Production scheduling

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Control and Systems Engineering
  • Human-Computer Interaction


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