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Proceedings Paper

Threshold residual ion concentration on photomask surface to prevent haze defects
Author(s): Jong-Min Kim; Jae-Chul Lee; Dong-Shik Kang; Dong-Heok Lee; Chul Shin; Moon-Hwan Choi; Sang-Soo Choi
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Paper Abstract

Haze generation has been serious issue on wafer lithography process, as illumination wavelength become shorter with 248nm and 193nm. Several published papers have been reported that ammonium and sulfate residual ion on mask surface is major source of haze generation. These ions are come from conventional photomask cleaning process. PKL have been studied new cleaning process to minimize haze generation and found cleaning process condition. Also, PKL found that residual ammonium ion is major source of haze generation than residual sulfate ion. New cleaning process improved residual ammonium ion concentration to less than 45 ppb from 900 ppb with conventional RCA cleaning. And illumination doses generating haze have been tested on five residual ammonium ion, 1500 ppb, 900 ppb, 160 ppb, 70 ppb, 45 ppb, respectively. In house designed Haze Acceleration Test Bench (HATB) was used to expose masks. Haze were not generated until from 25 kJ to 100 kJ, on 160 ppb to 45 ppb of ammonium ion concentration, respectively. And the residual of sulfate ion and its haze generation dose did not correspond. Residual ammonium ions need to be controlled tightly than sulfate ion. PKL concentrated on minimizing ammonium residual with new cleaning process and found the optimized cleaning process for preventing 100kJ of cumulative energy on ArF embedded attenuated PSM (EAPSM).

Paper Details

Date Published: 14 May 2007
PDF: 8 pages
Proc. SPIE 6607, Photomask and Next-Generation Lithography Mask Technology XIV, 66071Z (14 May 2007); doi: 10.1117/12.728982
Show Author Affiliations
Jong-Min Kim, PKL-Photronics R&D Ctr. (South Korea)
Jae-Chul Lee, PKL-Photronics R&D Ctr. (South Korea)
Dong-Shik Kang, PKL-Photronics R&D Ctr. (South Korea)
Dong-Heok Lee, PKL-Photronics R&D Ctr. (South Korea)
Chul Shin, PKL-Photronics R&D Ctr. (South Korea)
Moon-Hwan Choi, PKL-Photronics R&D Ctr. (South Korea)
Sang-Soo Choi, PKL-Photronics R&D Ctr. (South Korea)

Published in SPIE Proceedings Vol. 6607:
Photomask and Next-Generation Lithography Mask Technology XIV
Hidehiro Watanabe, Editor(s)

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