Paper
28 July 1997 Analysis of x-ray mask distortion
Yuusuke Tanaka, Takuya Yoshihara, Shinji Tsuboi, Kiyoshi Fujii, Katsumi Suzuki
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Abstract
We measured the x-ray mask distortion induced in the back- etching step in wafer processing and evaluated the contributions of SiN or SiC membrane stress and its uniformity along with Ta absorber stress and its uniformity to the distortion. Membrane stress nonuniformity causes a large amount of distortion in SiC membrane masks while it causes a small amount in SiN membrane masks. Absorber stress nonuniformity causes a large amount of distortion in Ta/SiN membrane masks, but it is expected to be reduced by 60% in Ta/SiC membrane masks. In wafer processing, therefore, the main cause of the distortion in Ta/SiN membrane masks is SiN membrane stress and absorber stress nonuniformity while in Ta/SiC membrane masks it is SiC membrane stress and its nonuniformity. We used these distortion component data to estimate the distortion induced in membrane processing. The distortion caused by SiN or SiC membrane stress is expected to be zero and the distortion caused by SiN or SiC membrane stress nonuniformity is expected to be less than 10 nm in membrane processing. As a result, for a pattern density of 50%, adopting membrane processing would reduce process-induced distortion by 50% in Ta/SiN membrane masks and by 75% in Ta/SiC membrane masks. The combination of SiC membranes and membrane processing significantly reduces process-induced distortion.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yuusuke Tanaka, Takuya Yoshihara, Shinji Tsuboi, Kiyoshi Fujii, and Katsumi Suzuki "Analysis of x-ray mask distortion", Proc. SPIE 3096, Photomask and X-Ray Mask Technology IV, (28 July 1997); https://doi.org/10.1117/12.277274
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KEYWORDS
Distortion

Photomasks

Silicon carbide

X-rays

Semiconducting wafers

Silicon

Tantalum

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