Organic monolayers covalently bonded to Si as ultra thin photoresist films in vacuum ultra-violet lithography

In this paper, we report on the application of our VUV patterning method to a SAM covalently attached to Si substrates as an alchoxy (Si-O-R) form. Although, we have, so far, focused mainly on the VUV-patterning of organosilane SAMs prepared on oxide-covered Si substrates, the organosilane SAMs are not satisfactory durable as a masking material in some types of chemical etching processes. For example, the underlying oxide layer is readily damaged with hydrofluoric (HF) acid and the SAMs are exfoliated in a short time. SAMs covalently bonded to Si through Si-C or Si-O-C bonds are promising as alternatives.