Potential Cause of Inhomogeneous Acid Distribution in Chemically Amplified Resists for Post Optical Lithography

Abstract

In chemically amplified resists for ionizing radiation such as an electron beam and EUV, protons of acids are mainly generated by the deprotonation of base polymers. Therefore, the acid generation efficiency depends highly on polymer structure. In recent resist formulas, partially protected poly(4-hydroxystyrene) has often been used as a base polymer. In this work, the effects of protecting groups on acid generation were investigated. We found differences in acid generation efficiency caused by protecting groups. These differences are likely to affect acid distribution.