Title
Feedback Control of Cluster Tools: Stability Against Random Time Disruptions
Abstract
In this research, we examine <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">feedback control</i> -based cluster tool scheduling methods to maintain <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">consistent</i> wafer sojourn times when a tool is subject to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">random disruptive events</i> . In our previous work, we proposed a feedback control design that regulates wafer sojourn times not to exceed the upper limits on wafer delays in a deterministic processing environment. Although such a feedback controller may ensure that wafer delay upper limits are always satisfied, it does not necessarily guarantee that the tool always restores its initial tool state after the occurrence of time disruptive events. This article thus further examines under which conditions a feedback controller enforces the wafer sojourn times to be <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">stabilized</i> in a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">stochastic</i> processing environment with unexpected random time disruptions. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —In semiconductor manufacturing, excessive wafer sojourn times at wafer fabrication tools increase the risk of wafer quality failures. In particular, the wafer quality fluctuates when the sojourn times are inconsistent over different wafers. Therefore, in cluster tools, wafer sojourn times are often strictly regulated to be minimized or to remain constant with an objective of reducing the risk of wafer quality degradation. In this research, we examine a cluster tool scheduling framework that enables to maintain stable tool operations even when a tool is randomly disrupted by unexpected exceptional events.
Year
DOI
Venue
2022
10.1109/TASE.2021.3070346
IEEE Transactions on Automation Science and Engineering
Keywords
DocType
Volume
Cluster tool,feedback control,random time disruption,stability
Journal
19
Issue
ISSN
Citations 
3
1545-5955
0
PageRank 
References 
Authors
0.34
25
3
Name
Order
Citations
PageRank
Chulhan Kim100.68
Tae-Sun Yu200.34
Tae-Eog Lee328530.02