NEW COPOLYMER, PHOTORESIST COMPOSITION, AND METHOD FOR FORMING HIGH-ASPECT-RATIO RESIST PATTERN

摘要

PROBLEM TO BE SOLVED: To provide a chemically amplified photoresist composition suitable for use in a process for forming a high-aspect-ratio resist pattern by using a silylating agent and exhibiting an excellent transmittance, a high sensitivity, and a high resolution, and a high depth of focus in the field of photolithography using a light source in the DUV(deep ultraviolet) region, a new copolymer suitable for the preparation of the same, and a method for forming a high- aspect-ratio resist pattern. SOLUTION: The new copolymer essentially consists of (A) repeating units represented by formula I and (B) repeating units derived from an unsaturated carboxylic acid anhydride.