Extendibility of synchrotron radiation lithography to the sub-100 nm region

Abstract

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 μm 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 μm. The effects of mask duty [which is defined to be the ratio of the absorber (line) width to the pattern pitch, i.e., duty cycle] on the optimum exposure dose and mask linearity are also evaluated.