17 May 1994 Focusing and leveling system using position-sensitive detectors for the wafer steppers
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An optical focus and leveling system for ETRI KrF excimer laser stepper is developed using position sensitive detectors (PSD) and optical magnification method. This type of detection method showed focusing and leveling accuracies of about +/- 0.1 micrometers and +/- 1.0 arcsec (+/- 0.5 X 10-5 rad) respectively. Also, we confirmed experimentally the autofocus system has +/- 0.15 micrometers signal stability within the controlled temperature range of +/- 0.1 degree(s)C. In this paper, we report the design concepts of the focusing and leveling system and the characteristics of the system parameter applied to ETRI KrF excimer laser stepper.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Dohoon Kim, Dohoon Kim, Won-Ick Jang, Won-Ick Jang, Boo-Yeon Choi, Boo-Yeon Choi, Youngjik I. Lee, Youngjik I. Lee, Jong-Hyun Lee, Jong-Hyun Lee, Hyung Joun Yoo, Hyung Joun Yoo, S. W. Kang, S. W. Kang, Jin Hyuk Kwon, Jin Hyuk Kwon, "Focusing and leveling system using position-sensitive detectors for the wafer steppers", Proc. SPIE 2197, Optical/Laser Microlithography VII, (17 May 1994); doi: 10.1117/12.175492; https://doi.org/10.1117/12.175492

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