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Proceedings Paper

Implementation of attenuated PSMs in DRAM production
Author(s): Tatsuo Chijimatsu; Toru Higashi; Yasuko Tabata; Naoyuki Ishiwata; Satoru Asai; Isamu Hanyu
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Paper Abstract

We studied the use of attenuated phase shift mask (PSM) in DRAM production. There exists several problems with the use of an attenuated PSM compared to a conventional Cr mask. These include a need to form an opaque region, facilitate reticle alignment with a stepper, and optimize mask bias to prevent side peak printing. First, we investigated the characteristics of checkerboard patterns in achieving an opaque region. We confirmed the feasibility of making a mask to maintain opaqueness. Next we developed a mask fabrication process so to enable reticle alignment in some kinds of steppers by using an additional Cr layer under the attenuated layer. Finally, we tried to implement attenuated PSM in a previous generation stepper. We found that we must pay attention to lens aberration when optimizing mask bias.

Paper Details

Date Published: 7 June 1996
PDF: 12 pages
Proc. SPIE 2726, Optical Microlithography IX, (7 June 1996); doi: 10.1117/12.240918
Show Author Affiliations
Tatsuo Chijimatsu, Fujitsu Ltd. (Japan)
Toru Higashi, Fujitsu Ltd. (Japan)
Yasuko Tabata, Fujitsu Ltd. (Japan)
Naoyuki Ishiwata, Fujitsu Ltd. (Japan)
Satoru Asai, Fujitsu Ltd. (Japan)
Isamu Hanyu, Fujitsu Ltd. (Japan)

Published in SPIE Proceedings Vol. 2726:
Optical Microlithography IX
Gene E. Fuller, Editor(s)

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