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Proceedings Paper

Phase-shifting mask design tool
Author(s): David M. Newmark; Andrew R. Neureuther
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Paper Abstract

A Computer Aided Design tool is being developed to automatically produce design graphs that will facilitate the layout of phase-shift masks. This tool is a design interface which utilizes SPLAT1 for the aerial image simulations. The program accepts a user specified geometry and the mask parameter space to be explored. It then automatically extracts information such as intensity, contrast, space width, line width, and intensity slope from the SPLAT results for each iteration. In this paper, we apply the design system to a number of phase-shift mask patterns to explore design rule tradeoffs. For dark field masks with isolated spaces and Levenson arrays of spaces, we determine that a shrink of the mask combined with a bloat of open areas shows promise as a means of designing phase-shift masks if one is willing to sacrifice distance between light areas. By examining several typical mask patterns, we also show that an overall shrink of the mask does not require special design rules for each type of feature, but better scaling could result by appropriately developing new rules for different patterns. Since printing clear field masks is also important, we further probe the scalability of phase transitions. We show that a phase transition of 0.6 A/NA is the optimum length to achieve the highest intensity throughout the phase transition region. For 90 degree transitions, a length of 0.6 A/NA is needed while for 60-120 degree transitions, each step transition region must be at least 0.6 A/NA long. Finally, we present a new mask pattern for chains of contacts that has high intensity slope for a pitch of 1.2 A/NA and below.

Paper Details

Date Published: 1 January 1992
PDF: 10 pages
Proc. SPIE 1604, 11th Annual BACUS Symposium on Photomask Technology, (1 January 1992); doi: 10.1117/12.56946
Show Author Affiliations
David M. Newmark, Univ. of California/Berkeley (United States)
Andrew R. Neureuther, Univ. of California/Berkeley (United States)


Published in SPIE Proceedings Vol. 1604:
11th Annual BACUS Symposium on Photomask Technology
Kevin C. McGinnis, Editor(s)

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