Dissolution inhibitors for 193-nm chemically amplified resists

Dissolution characteristics and adhesion of 193-nm resists have been investigated by using molecular orbital calculations. The calculation indicated that naphthalene compound had better adhesion than alicyclic compounds by a factor of 1.2. Another calculation result obtained indicated that naphthalene was more hydrophilic than alicyclic compounds. In order to improve the adhesion and dissolution characteristics of the alicyclic resist, introduction of the naphthalene backbone into alicyclic resists was attempted in the form of additives (dissolution inhibitors) or copolymer components. Dissolution inhibitors that have simultaneously a naphthol novolak backbone and a characteristic generate carboxylic acid, such as tetrahydropyranyl ester of naphthol novolak compound condenced with glyoxlic acid (NV4THP), were the most effective dissolution inhibitors increasing dry etch resistance of base polymer by 14% and pattern resolution of original resist by 10%. The naphthalene dissolution inhibitor also largely improves pattern adhesion. These results were consistent with above-mentioned calculation results. 193-nm resists containing vinyl naphthalene in the copolymer structure were also investigated and fundamental resist requirements were satisfied with this polymer by adding adamantane dissolution inhibitor di-tert-butyl 2-((1-adamanthyl)carbonylmethyl) malonate (ADTB).