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Proceedings Paper

Shot number analysis at 65-nm node mask writing using VSB writer
Author(s): Junji Hirumi; Koki Kuriyama; Nobuyuki Yoshioka; Ryoichi Yoshikawa; Yutaka Hojo; Takashi Matuzaka; Kazumitsu Tanaka; Morihisa Hoga
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Paper Abstract

It depends for the writing time of variable shaped electron-beam (VSB) writing system on the number of writing shots. For shortening of writing time, it is most effective to reduce the number of shots. However, Resolution Enhancement Technologies (RET), such as OPC and PSM, make the VSB shot number increase explosively, in addition to reduction of LSI pattern size, and worsens the writing throughput. This is a serious problem for VSB mask writer, and the improvement of a writing throughput is required. In order to solve this problem, we inquired towards diversifying beam shape only from a rectangle. First, we investigated about the curtailment effect of the number of shots by trapezoid aperture adoption. Some latest VSB writer has adopted a triangle shaped aperture to compose the slanting figure in the LSI pattern efficiently. We investigated the efficiency of forming the slanting figure with trapezoid or parallelogram apertures compared with initial triangle aperture shot number. As the result of that, shown in Fig.1, we obtained the result that the shots number was reduced into 50% or more compared with initial triangle shots number. And, we examined a possibility of uniting and applying the character projection (CP) technique, which is adopted as EB direct writing (DW), to mask writing. Since pattern size is, for example, 4 times larger in the case of mask writing compared with the case of EBDW, the area that can extract a common CP pattern out from LSI patterns at mask writing is smaller than EBDW. Then, we extracted CP aperture pattern from cell library data for logic LSI. We obtained the result, shown in Fig.2, that the shot number that was used CP aperture was reduced into about 35% compared with initial VSB shots number. However, the arrangement number of aperture has restriction, and if the arrangement number decreases, the curtailment rate of the shots number will fall. These two techniques are fundamentally effective in curtailment of writing shots number. Furthermore, we will discuss with the possibility of applying these techniques to mask writing and with some problems to solve for the application of these techniques.

Paper Details

Date Published: 28 August 2003
PDF: 9 pages
Proc. SPIE 5130, Photomask and Next-Generation Lithography Mask Technology X, (28 August 2003); doi: 10.1117/12.504259
Show Author Affiliations
Junji Hirumi, Semiconductor Leading Edge Technologies, Inc. (Japan)
Koki Kuriyama, Semiconductor Leading Edge Technologies, Inc. (Japan)
Nobuyuki Yoshioka, Semiconductor Leading Edge Technologies, Inc. (Japan)
Ryoichi Yoshikawa, NuFlare Technology Inc. (Japan)
Yutaka Hojo, Hitachi High-Technologies Corp. (Japan)
Takashi Matuzaka, Hitachi High-Technologies Corp. (Japan)
Kazumitsu Tanaka, JEOL Ltd. (Japan)
Morihisa Hoga, Dai Nippon Printing Co., Ltd. (Japan)

Published in SPIE Proceedings Vol. 5130:
Photomask and Next-Generation Lithography Mask Technology X
Hiroyoshi Tanabe, Editor(s)

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