Negative (meth)acrylate resist materials based on novel crosslinking chemistry
Novel negative-tone resist materials suitable for 193 nm and e-beam lithography, based on newly-synthesized (meth)acrylate copolymers that contain (2-hydroxyethyl methacrylate) as the necessary component for imaging and aqueous base development, are presented. A representative resist of this class is formulated using poly(2-hydroxyethyl methacrylate-co-cyclohexyl methacrylate-co-isobornyl methacrylate-co-acrylic acid) (PHECIMA) and a sulfonium salt photo acid generator. The negative image formation is based on acid induced crosslinking of the hydroxyl groups of the 2-hydroxyethyl methacrylate (HEMA) moieties. The negative resist presented no swelling phenomena in the aqueous base developer and enhanced etch resistance. Dense 0.18 ?m and isolated 0.13 ?m lines have been obtained upon 193 nm and e-beam lithography establishing PHECIMAs resist formulations as promising candidates for high-resolution lithography upon a further material and process optimization.
e-beam lithography 2-hydroxyethyl methacrylate negative resist etch resistance acrylates acrylate copolymers 193 nm optical lithography deep-uv resist