The focus monitor technique has been shown to be a unique and promising method of characterizing lithography tools. The focus monitor test mask employs phase shifting to translate focus error into a measurable overlay error, independent of exposure. We have also employed an exposure monitor structure to measure dose, independent of focus. The combination of focus and exposure monitors is highly sensitive to factors which affect critical dimensions. Using this test mask we have systematically analyzed the performance of the photo processing tools on our line. This paper will review the data and discuss process capability improvements using both methodologies.

Date Published: 26 May 1995
PDF: 10 pages
Proc. SPIE 2440, Optical/Laser Microlithography VIII, (26 May 1995); doi: 10.1117/12.209321

Published in SPIE Proceedings Vol. 2440:
Optical/Laser Microlithography VIII
Timothy A. Brunner, Editor(s)