Sulfonium salt monomer, polymer, chemically amplified resist composition, and pattern forming method

Abstract

This invention provides a strontium salt monomer used in a chemical amplification inhibitor composition for photolithography using high-energy rays. This composition exhibits excellent solvent solubility, high sensitivity, high contrast, and superior photolithography performance (LWR, CDU, EL, DOF, etc.), as well as excellent resistance to pattern collapse and etching resistance during fine pattern formation. The invention also includes a polymer containing repeating units from the strontium salt monomer, a chemical amplification inhibitor composition containing the polymer, and a pattern formation method using the chemical amplification inhibitor composition. A strontium salt monomer is represented by formula (a), where Z- is a carboxylic acid anion having an aromatic vinyl structure and an iodine atom. A sulfonium salt monomer having the following formula (a): wherein Z- is a carboxylic acid anion having an aromatic vinyl structure and an iodine atom.