Effect of Additives in ArF Single Layer Chemical Amplification Photoresist.

Abstract

This paper describes a new approach to the design of positive-tone ArF single layer chemical amplification (CA) photoresist. The main issue is the effect of small molecular compounds as additives in methacrylic-based ArF CA photoresist. Three alicyclic compounds with adamantyl moiety and two aromatic compounds with naphthyl moiety were selected as additives. Their influences on the photoresist properties were examined and clarified as follows: •Transparency of the resist film at 193-nm could be controlled by the loading level and the sorts of additives. Alicyclic additives made the resist film more transparent. •Both the photospeed and the contrast of the resist were drastically influenced by the loaded additives. Enhancement of the photospeed was easily achieved. •Thermal properties of the resist film could also be affected by additives. However, the effect was generally temperate. •The loaded additives could mitigate T-top formation of resist profile due to the control of the inherent dissolution rate of the resist.Loading the additives would compensate some inherent defects of matrix acrylic polymers and consequently allow considerable latitude in resist design of ArF CA resist. A three component system comprising an acrylic polymer, a photoacid generator, and adamantanecarboxylic acid showed good imaging performance (0.26μmL/S, 35mJ/cm2) on KrF exposure.