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

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, photo acid 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 40mJ/cm(2) with the standard developer, NMD-3 2.38%.