Wafer admission control for clustered photolithography tools

Kyungsu Park, James R. Morrison

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


In semiconductor wafer manufacturing, clustered photolithography scanners frequently use pre-scan or post-scan wafer buffers to ensure that the scanner is seldom starved of wafers or blocked from further production. While such practice is essential to maximize the throughput of this costly tool, state-of-the-art methods for determining when to use the buffer are overly cautious. As a consequence, each wafer's residency time in the tool may be significantly larger than necessary and the time a lot spends inside the cluster is increased. Since satisfaction of time windows and reduction in wafer residency time in a tool will arguably improve yield and reduced lot process time will increase manufacturing deployment opportunities, we strive to minimize residency time while maintaining maximum throughput. To achieve our goal, we develop wafer admission control algorithms considering setups and transient operation. The output of the algorithm is suggested wafer entry times to the tool and is intended to be used by the wafer handling robot as a guideline. We simulate several representative systems to verify the performance of the approach. For a typical system, it is shown that, while maintaining throughput, the wafer residency time, the lot process time and the wafer buffer occupancy are reduced by 54%, 31% and 67%, respectively. The lot deployment opportunity in the same case is increased by 14%. As a consequence, there are fewer wafers for the wafer handling robots to serve and the tool may be designed with fewer buffer slots. The concept and algorithm will thus improve clustered photolithography performance in numerous ways.

Original languageEnglish
Title of host publication2010 IEEE/SEMI Advanced Semiconductor Manufacturing Conference, ASMC 2010
Number of pages6
StatePublished - 2010
Event2010 IEEE/SEMI Advanced Semiconductor Manufacturing Conference, ASMC 2010 - San Francisco, CA, United States
Duration: Jul 11 2010Jul 13 2010

Publication series

NameASMC (Advanced Semiconductor Manufacturing Conference) Proceedings
ISSN (Print)1078-8743


Conference2010 IEEE/SEMI Advanced Semiconductor Manufacturing Conference, ASMC 2010
Country/TerritoryUnited States
CitySan Francisco, CA


Dive into the research topics of 'Wafer admission control for clustered photolithography tools'. Together they form a unique fingerprint.

Cite this