Paper
5 September 2001 Thermal response of EUVL mask substrate during dry etching process
Akira Chiba, Eiichi Hoshino, Makoto Takahashi, Hiromasa Yamanashi, Hiromasa Hoko, Byoung Taek Lee, Takashi Yoneda, Masaaki Ito, Taro Ogawa, Shinji Okazaki
Author Affiliations +
Abstract
In the fabrication of an EUVL mask, some of the highest temperatures probably occur during the dry etching step. The thermal response of an EUVL mask during dry etching was investigated through simulations. In order to estimate the power absorbed during dry etching, the temperature of a glass wafer was measured by observing the change in color of a heat-sensitive label pasted on it. The measured results were compared with simulation results obtained using a lumped heat capacity model. The absorption ration was found to be 0.25-0.35, and there was good agreement between the measured and simulation data. In order to calculate the time-wise change in temperature, an internal energy balance model based on a large number of small elements was developed. To handle mask deflection caused by the temperature gradient in the thickness direction, a first- approximation model based on spherical deformation and free boundary conditions was used. The temperature gradient in an EUVL mask that arises during dry etching was clarified. The amount of thermal deflection was found to be much smaller when masks are made on ULE of Si substrates than on quartz.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Akira Chiba, Eiichi Hoshino, Makoto Takahashi, Hiromasa Yamanashi, Hiromasa Hoko, Byoung Taek Lee, Takashi Yoneda, Masaaki Ito, Taro Ogawa, and Shinji Okazaki "Thermal response of EUVL mask substrate during dry etching process", Proc. SPIE 4409, Photomask and Next-Generation Lithography Mask Technology VIII, (5 September 2001); https://doi.org/10.1117/12.438369
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KEYWORDS
Photomasks

Extreme ultraviolet lithography

Dry etching

Silicon

Semiconducting wafers

Glasses

Temperature metrology

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