Share Email Print

Proceedings Paper

Impact of EUV mask quality on optical inspection sensitivity
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

EUV masks are exposed at a wavelength of 13.4 nm, but patterned mask inspection will be in the wavelength range of 157 nm to 257 nm. This large mismatch in wavelength raises questions as to whether the defects that are found in inspection will be the defects that print in a EUV exposure tool. This paper addresses part of this question by considering how small certain nuisance defects must be in order to not limit the optical inspection tool’s sensitivity. That is, the tool must be capable of finding critical printing defects and must not find nonprinting defects. A nuisance defect is considered to be one that the inspection tool may be sensitive to, but will not print on a wafer. We have used a 3D Maxwell equation simulator to simulate the inspection images obtained for a variety of nuisance defects of different types and sizes. We have done these calculations assuming that the EUV lithography will be performed at mask dimensions of 200 nm lines and spaces with a 4X mask, so the features would print at 50 nm lines and spaces. We have determined the critical size of such nuisance defects to be 40nm or larger, depending on defect type. Nuisance defects larger than about 40 nm square may limit the inspection tool’s sensitivity to printing defects. The ITRS roadmap specification for patterned defects at the 50 nm node is 40 nm. Therefore, the limit in size for such nuisance defects is not more stringent than the limits that must be met to match the patterned defect size specification. This work should provide guidance in developing a EUV mask specification that ensures that inspection tools will be able to meet the needs of EUV lithography. This work has been sponsored in part by NIST-ATP Cooperative Agreement #70NANB8H44024.

Paper Details

Date Published: 27 December 2002
PDF: 8 pages
Proc. SPIE 4889, 22nd Annual BACUS Symposium on Photomask Technology, (27 December 2002); doi: 10.1117/12.467439
Show Author Affiliations
Donald W. Pettibone, KLA-Tencor Corp. (United States)
Aditya Dayal, KLA-Tencor Corp. (United States)
Stanley E. Stokowski, KLA-Tencor Corp. (United States)

Published in SPIE Proceedings Vol. 4889:
22nd Annual BACUS Symposium on Photomask Technology
Brian J. Grenon; Kurt R. Kimmel, Editor(s)

© SPIE. Terms of Use
Back to Top