Optimization of line edge roughness before and after etching with photoresist in soft X-ray interference lithography

Soft X-ray interference lithography is a new micro-nano fabrication technology which uses multi beam soft X-ray to form interference field to expose photoresist. Due to the photochemical sensitivity of photoresist, the required fine patterns can be transferred from the mask to the substrate after exposure, development and etching. It is also a technique of frequency doubling of mask period. In this paper, the change of line edge roughness of micro-nano pattern before and after photoresist etching is studied. The results show that the line edge roughness of micro-nano structure after etching is better than that before etching. The line edge roughness of the etched nano pattern is 2.20 nm, which is two thirds the line edge roughness compared with 3.35 nm before etching. The height uniformity of the etched nano pattern is also optimized This paper provides a reasonable support for soft X-ray interference lithography to fabricate accurate micro-nano patterns by selecting appropriate substrate material, exposure parameters and etching process.