Two‐layer resist fabrication by new portable conformable masking i‐line lithography

A new technique for submicron optical lithography is reported. Water‐soluble contrast enhancing material for i‐line exposure prevented the undercut profile of negative photoresist and attained high‐aspect‐ratio rectangular patterns. New portable conformable masking i‐line lithography using the water‐soluble contrast enhancing material could successfully fabricate a two‐layer resist composed of negative photoresist RU‐1100N as a top layer and positive deep ultraviolet resist poly(dimethylglutarimide) as a bottom layer.