X-ray absorbing and mechanical properties of Au-C film for x-ray mask absorber

Hiroshi Fukushima; Hitomi Yamada; Teruyuki Matsui; Takashi Tagawa; Shinzo Morita; Shuzo Hattori

doi:10.1117/12.20165

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1 May 1990 X-ray absorbing and mechanical properties of Au-C film for x-ray mask absorber

Hiroshi Fukushima, Hitomi Yamada, Teruyuki Matsui, Takashi Tagawa, Shinzo Morita, Shuzo Hattori

Author Affiliations +

Proceedings Volume 1263, Electron-Beam, X-Ray, and Ion-Beam Technology: Submicrometer Lithographies IX; (1990) https://doi.org/10.1117/12.20165
Event: Microlithography '90, 1990, San Jose, CA, United States

Abstract

The X-ray absorption and mechanical properties of gold containing (Au-C) absorber formed on polyimide membrane for X-ray lithography mask have been investigated. The Au-C films were deposited by the same method as the previous investigators(Itoh et al.)1. (1) The compositional dependence of film stress before and after the exposure to SOR radiation has been observed. As a result, the stress in film changed monotonically ranging from compression (-3xlO8N/m2) to tension (l.2xlO8N/m2) with increasing Au content. Zero film stress was observed at Au atomic composition of 30%. Films originally being compressive (-l.5xlO7N/m2) were found to become tensile (l.OxlO8N/m2) after absorbing l500J/cm3 X-ray. This tendency differs from that of the BN film observed by King et al (2) X-ray absorption ratio in Au-C films were determined by measuring the amount of reduced thickness of resist on development after the exposure of X-ray through Au-C films with various composition ratios. It was found that it tended to fall from 92% to 68% with a decrease of Au atomic composition ratio from 0.85 to 0.11 at the constant absorber thickness of 0.5 pm. (3) Au-C films of various atomic composition ratio were patterned with EB lithography using the PMMA(Polyrnethylmethacrylate) resist and Reactive Ion Etching (RIE) with 02 gas. It was found that the etching rate of the film decreases with increasing Au content. The typical obtained value was approximately 100A/min at around 50% to 60% of Au composition and this was about 4 times higher than etching rate of pure Au. It is concluded that the Au-C absorber on polyimide membrane X-ray mask is practical for VLSI use for submicron pattern fabrication.

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Hiroshi Fukushima, Hitomi Yamada, Teruyuki Matsui, Takashi Tagawa, Shinzo Morita, and Shuzo Hattori "X-ray absorbing and mechanical properties of Au-C film for x-ray mask absorber", Proc. SPIE 1263, Electron-Beam, X-Ray, and Ion-Beam Technology: Submicrometer Lithographies IX, (1 May 1990); https://doi.org/10.1117/12.20165

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