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Proceedings Paper

Wafer plane inspection evaluated for photomask production
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Paper Abstract

Wafer Plane Inspection (WPI) is a novel approach to inspection, developed to enable high inspectability on fragmented mask features at the optimal defect sensitivity. It builds on well-established high resolution inspection capabilities to complement existing manufacturing methods. The production of defect-free photomasks is practical today only because of informed decisions on the impact of defects identified. The defect size, location and its measured printing impact can dictate that a mask is perfectly good for lithographic purposes. This inspection - verification - repair loop is timeconsuming and is predicated on the fact that detectable photomask defects do not always resolve or matter on wafer. This paper will introduce and evaluate an alternative approach that moves the mask inspection to the wafer plane. WPI uses a high NA inspection of the mask to construct a physical mask model. This mask model is used to create the mask image in the wafer plane. Finally, a threshold model is applied to enhance sensitivity to printing defects. WPI essentially eliminates the non-printing inspection stops and relaxes some of the pattern restrictions currently placed on incoming photomask designs. This paper outlines the WPI technology and explores its application to patterns and substrates representative of 32nm designs. The implications of deploying Wafer Plane Inspection will be discussed.

Paper Details

Date Published: 17 October 2008
PDF: 9 pages
Proc. SPIE 7122, Photomask Technology 2008, 71221B (17 October 2008); doi: 10.1117/12.801945
Show Author Affiliations
Emily Gallagher, IBM Corp. (United States)
Karen Badger, IBM Corp. (United States)
Mark Lawliss, IBM Corp. (United States)
Yutaka Kodera, Toppan Photomask, Inc. (United States)
Jaione Tirapu Azpiroz, IBM Corp. (United States)
Song Pang, KLA-Tencor Corp. (United States)
Hongqin Zhang, KLA-Tencor Corp. (United States)
Eugenia Eugenieva, KLA-Tencor Corp. (United States)
Chris Clifford, KLA-Tencor Corp. (United States)
Arosha Goonesekera, KLA-Tencor Corp. (United States)
Yibin Tian, KLA-Tencor Corp. (United States)

Published in SPIE Proceedings Vol. 7122:
Photomask Technology 2008
Hiroichi Kawahira; Larry S. Zurbrick, Editor(s)

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