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Proceedings Paper

New optimization method of exposure with alternative phase-shifting masks
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Paper Abstract

A new method to optimize the structure of an alternative phase shifting mask (alt-PSM) with dual trench type has been developed form the viewpoint of pattern placement error as well as conventional factors of light intensity contrast and exposure-defocus window (ED-window). By using this, the pattern placement error caused by either the phase error or defocus has been reduced. By the simulation, the optimum structure for reducing the pattern placement error is with a phase difference of about 170 degree(s) between phase shifted and non-shifted area. The pattern placement error for 0.13 micrometers lines and spaces can be reduced to less than 2.5 nm from -0.3 to 0.3 micrometers defocus by this optimum. A high contrast and a large ED-window can be obtained as well. However, high accuracy of mask fabrication technique is required. In the experiment, we have evaluated line and space patterns for a 0.13 micrometers node logic gate design rule. It showed less than 7.5 nm errors in the required DOF for the mask with the optimized mask structure.

Paper Details

Date Published: 5 September 2001
PDF: 11 pages
Proc. SPIE 4409, Photomask and Next-Generation Lithography Mask Technology VIII, (5 September 2001); doi: 10.1117/12.438397
Show Author Affiliations
Koji Kikuchi, Sony Corp. (Japan)
Hidetoshi Ohnuma, Sony Corp. (Japan)
Hiroichi Kawahira, Sony Corp. (Japan)

Published in SPIE Proceedings Vol. 4409:
Photomask and Next-Generation Lithography Mask Technology VIII
Hiroichi Kawahira, Editor(s)

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