In LP-CVD process, preparation of silicon nitride film with small tensile stress and low refractive index was investigated as a function of deposition temperature and reactant gas ratio (SiH2Cl2/NH3). The small stress film with low refractive index can be prepared easily by high temperature deposition. Applying the film to an x-ray mask membrane, a new silicon nitride single-layer x-ray mask with a large area window (such as 50 mm in diameter) and high transparency to visible light is realized. Using this mask, a submicron resist pattern (0.5 μm line and space) can be replicated easily by Si–K x-ray exposure system.

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Studies on correction accuracy of proximity effect for the pattern area density method in electron beam direct writing J.This article discusses the resolution of synchrotron radiation lithography in the sub-100 nm region, taking into consideration the mass production of large-scale integrated circuits, under attainable conditions for the x-ray mask, proximity gap, and resist processes. Resolution and exposure latitude for line-and-space patterns are markedly improved by using a mask with a contrast of only 2.5. Resolutions of 90, 80, 70, and 60 nm can be achieved with proximity gaps of 30, 20, 15, and 10 m if a high-contrast resist and a low-surface tension developer are used. The latitude will be 10% for pattern sizes as small as 70 nm when the proximity gap is narrower than 15 m. The effects of mask duty ͓which is defined to be the ratio of the absorber ͑line͒ width to the pattern pitch, i.e., duty cycle͔ on the optimum exposure dose and mask linearity are also evaluated.