To provide a polymer compound suitable for a base resin of a positive resist material, particularly for a chemically amplified positive resist material, which exhibits high resolution, wide exposure latitude, a small dimensional difference between a sparse pattern and a dense pattern, and good process adaptability superior to those of conventional positive resist materials, gives an excellent pattern shape after exposure and is excellent in etching resistance, a positive resist material using the same and a pattern-forming method.
The polymer compound has at least a recurring unit represented by general formula (1) and a recurring unit derived from a monomer selected among indene, acenaphthylene, chromone, coumarin and norbornadiene, and a weight-average molecular weight within the range of 1,000-500,000. In the formula, R1 is a hydrogen atom or a methyl group; R2 is an acid-labile group; and k is 1 or 2. The positive resist material has a very high alkali resolution speed contrast between before and after exposure, exhibits high sensitivity and high resolution, gives an excellent pattern shape after exposure, exhibits a suppressed acid diffusion rate in particular and is excellent in etching resistance. Thus, the polymer compound gives the positive resist material particularly suitable as a fine pattern-forming material for manufacturing a very large scale integration or a photomask, particularly the chemically amplified positive resist material.
KUSAKI WATARU
TAKEDA TAKANOBU
Saori Shigematsu
Katsunari Kobayashi