Chemically amplified negative-tone resist using novel acryl polymer for 193-nm lithography

Abstract

We report the development of a novel acryl polymer with an (alpha) -hydroxymethyl acrylate in the application to 193nm chemically amplified negative-tone resist. This new polymer structure consists of ((alpha) -hydroxymethyl)acrylate and MAA. The ester and alcohol group in the polymer contribute to an intramolecule and/or intermolecular hybrid crosslinking reactions without crosslinker and in the presence of a photo generated acid as a catalysis. In an intramolecular crosslink reaction, the ester group reacts to a neighboring hydroxymethyl group within the polymer chain. As a result, a lactone group is made in the main polymer chain. On the other hand, in an intermolecular crosslink reaction, the ester group reacts to a hydroxymethyl group of another polymer chain to make an ester chain. In this reaction, the new polymer is densely crosslinked and fine resist pattern is obtained without having any swelling problem. Consequently, the resist is optimized and contains the new polymer, photoacid generator and a small amount of crosslinker. Under conventional illumination condition, 180nm line and space pattern are achieved without any kind of swelling problem. The sensitivity is 40 mJ/cm 2 with the standard developer, NMD-3 2.38 percent.