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Proceedings Paper

Resolution limits with 248-nm strong phase-shifting techniques for contact patterning applications
Author(s): Yulia O. Korobko; Mei-Chien Lu; Jesmar Telans; Jeffrey E. Powers
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Paper Abstract

As conventional lithography capability is reaching the limit, resolution enhancement becomes a crucial element to extend the lithography capability. The main purpose of this paper is to examine the capabilities and limitations of various phase shifting techniques. Using contact applications as an example, alternating and phase edge phase shifter were evaluated with single and double exposure techniques. Detailed discussion will include both simulation and experimental results. The PSM performances were predicted with Intel in-house simulator. Analysis was done based on aerial image formation using peak intensity and Modulation Transfer Function to evaluate resolution capabilities. For each type of phase shifter, good resolution enhancement was achieved with optimized pitch range of dense structures. Experimental results of focus-exposure matrices were taken on a DUV stepper with NA of 0.42. Significant resolution enhancement was demonstrated with k1 as low as 0.32 which is far below the limitation a k1 equals 0.5. Small contacts with tight pitch, i.e. 180 nm contact with 380 nm pitch, were demonstrated with reasonable depth of focus by using double exposure technique. By using single exposure alternating phase shifting technique pitches down to 460 nm is steadily resolved. With conventional mask, 350 nm contacts with 700 nm pitch is reported as the minimum printable range for the same stepper.

Paper Details

Date Published: 18 December 1998
PDF: 12 pages
Proc. SPIE 3546, 18th Annual BACUS Symposium on Photomask Technology and Management, (18 December 1998); doi: 10.1117/12.332858
Show Author Affiliations
Yulia O. Korobko, Intel Corp. (United States)
Mei-Chien Lu, Intel Corp. (United States)
Jesmar Telans, Intel Corp. (United States)
Jeffrey E. Powers, Intel Corp. (United States)

Published in SPIE Proceedings Vol. 3546:
18th Annual BACUS Symposium on Photomask Technology and Management
Brian J. Grenon; Frank E. Abboud, Editor(s)

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