Title
Scheduling Cluster Tools for Concurrent Processing of Two Wafer Types
Abstract
We examine a scheduling problem of cluster tools that concurrently process two wafer types in a cyclic operational sequence. Whereas the process steps for different wafer types are assigned to different processing modules (PMs), the wafer loading and unloading tasks at the PMs are performed by a single robot. For a given cycle plan, which is a mix of different wafers for each cycle, we wish to determine the robot task sequence so as to minimize the tool cycle time. When a single wafer type is processed, the backward and swap sequences are optimal for single-armed and dual-armed tools, respectively. They are being prevalently used because of their simplicity and robustness. To maintain such advantages in concurrent processing, we introduce and define the concurrent backward and swap sequences (CBSs and CSSs, respectively). We then develop conditions on process times, robot task times, and the number of wafers produced in a cycle for which such CBSs and CSSs are still optimal for concurrent processing. We also show that, for some special cases, the two wafer types can achieve their maximum throughput rates as if each wafer type exclusively uses the tool regardless of other wafer types in progress. When the developed conditions do not hold, an effective mixed integer programming (MIP) model based on the CBSs and CSSs is used for robot task sequencing. Finally, we experimentally verify its efficiency and effectiveness by comparing to the existing scheduling methods for optimal scheduling of cluster tools.
Year
DOI
Venue
2014
10.1109/TASE.2013.2296855
IEEE T. Automation Science and Engineering
Keywords
Field
DocType
Robots,Throughput,Loading,Interference,Job shop scheduling,Upper bound,Cascading style sheets
Wafer,Petri net,Production control,Job shop scheduling,Concurrent engineering,Scheduling (computing),Computer science,Robustness (computer science),Real-time computing,Control engineering,Integer programming,Computer engineering
Journal
Volume
Issue
ISSN
11
2
1545-5955
Citations 
PageRank 
References 
12
0.60
17
Authors
3
Name
Order
Citations
PageRank
Jun-Ho Lee122421.56
Hyun-Jung Kim2120.60
Tae-Eog Lee328530.02