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Proceedings Paper

Automatic on-line wafer stepper calibration system
Author(s): Martin A. van den Brink; Hans Franken; Stefan Wittekoek; Theo Fahner
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Paper Abstract

This paper introduces a new wafer stepper on-line calibration sensor, the Image Sensor, which refers directly to the aerial reticle image at the exposure wavelength. This sensor system is integrated with other stepper metrology systems by a so-called Image Sensor fiducial plate, which interacts simultaneously with the aerial reticle image, the Image Sensor, the TTL alignment system and the focus sensor of the stepper. An integrated software package ensures on-line regular stepper calibration, eliminating dependance on environmental, process and time parameters. Unique in this concept is the direct measurement of the consequence of wavelength drift in excimer laser steppers by measuring the aerial image deformation at the exposure wavelength. This information is used as a direct feedback to the wavelength control of the laser. Initial results of this system are presented for both UV (365 nm) and DUV (248 nm) steppers.

Paper Details

Date Published: 1 June 1990
PDF: 17 pages
Proc. SPIE 1261, Integrated Circuit Metrology, Inspection, and Process Control IV, (1 June 1990); doi: 10.1117/12.20056
Show Author Affiliations
Martin A. van den Brink, ASM Lithography BV (Netherlands)
Hans Franken, ASM Lithography BV (Netherlands)
Stefan Wittekoek, ASM Lithography BV (Netherlands)
Theo Fahner, ASM Lithography BV (Netherlands)

Published in SPIE Proceedings Vol. 1261:
Integrated Circuit Metrology, Inspection, and Process Control IV
William H. Arnold, Editor(s)

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