Theoretical calculations of sensitivity of deprotection reactions for acrylic polymers for 193 nm lithography

Abstract

The reaction energy of deprotection reactions, density of the reaction site, glass transition temperature, gas permeability, density and relative permittivity of photoresists of poly(TCDA₅–RMA₃–MAA₂) and poly(TCDMACOOR₄–TCDMACOOH₆) with various protection groups were calculated. The most-enhanced exothermicity was calculated for protection groups containing an ethoxyethyl group as compared to the other protection groups: tetrahydropyranyl, tricyclodecanyl and tert-butyl. For the ethoxyethyl protection groups, a good correlation was found between the experimental sensitivity and the calculated values of the relative permittivity and the glass transition temperature of the polymers. This indicates that calculating these properties of polymers can provide a quick way to identify polymers having a high sensitivity for ArF lithography.