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Proceedings Paper

Improvement of image quality and inspection speed in LM7500 reticle inspection system
Author(s): Hideyuki Moribe; Takeshi Bashomatsu; Kenichi Matsumura; Akira Uehara; Hiroyuki Takahashi
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Paper Abstract

By refining the entire optical system in our LM7500 reticle inspection system, we have successfully improved the image quality and inspection speed. The LM7500 system uses a beam scanning method in which the inspection pixel size is switched by changing the magnification ratio of the telescope in the section subsequent to the scanner's optical system. The telescope magnification ratio is designed to meet the requirements of the light spot diameter and beam scanning width on a reticle, and specifies the scanning speed. We have realized a smaller light spot diameter by improving the design of the section prior to the optical system, including the AOD (acousto-optic deflector), which is the starting point of the scanner's optics. This has led to faster scanning. We have also succeeded in minimizing the adjustment error by optimizing the magnification ratio of the telescope, thus increasing the adjustment margin of the incident light beam entering the section subsequent to the scanner's optical system. This means that the difference in the X and Y directions of an image can be suppressed to a remarkable extent for a beam scanning system. Moreover, because the LM7500 scans both transmitted and reflected light simultaneously, pattern inspections, particle inspections and even scribe-tri-tone inspections can be carried out at the same time. We have also succeeded in increasing the inspection speed by 30% through optical system optimization.

Paper Details

Date Published: 19 May 2008
PDF: 8 pages
Proc. SPIE 7028, Photomask and Next-Generation Lithography Mask Technology XV, 70282K (19 May 2008); doi: 10.1117/12.793090
Show Author Affiliations
Hideyuki Moribe, NEC Corp. (Japan)
Takeshi Bashomatsu, NEC Corp. (Japan)
Kenichi Matsumura, NEC Corp. (Japan)
Akira Uehara, NEC Control Systems, Ltd. (Japan)
Hiroyuki Takahashi, NEC Control Systems, Ltd. (Japan)

Published in SPIE Proceedings Vol. 7028:
Photomask and Next-Generation Lithography Mask Technology XV
Toshiyuki Horiuchi, Editor(s)

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