Sulfonium salt, chemically amplified resist composition and pattern forming process

Abstract

The present invention addresses the use of onium salts in chemical amplification inhibitor compositions that exhibit excellent solvent solubility, high sensitivity, high contrast, and superior photolithography properties such as LWR, CDU, MEF, EL, and DOF in photolithography using high-energy rays; chemical amplification inhibitor compositions containing the onium salt as photoacid generators; and pattern formation methods using the chemical amplification inhibitor compositions. The present invention provides a strontium salt composed of an aromatic sulfonic acid anion represented by formula (1A) and a strontium cation represented by formula (1B).