| 摘要 |
PROBLEM TO BE SOLVED: To provide a new base resin for a positive type resist giving a radiation sensitive chemical amplification type positive resist composition having high sensitivity and high resolution, ensuring good heat resistance, good focal depth-width characteristics, good aging stability relating to pattern form and good shelf stability of a resist solution and capable of forming a resist pattern having no substrate dependency and excellent in profile shape. SOLUTION: The base resin comprises a poly(hydroxystyrene) derivative consisting of 10-60 mol% constitutional units of formula (1) (where R1 is H or methyl; R2 is methyl or ethyl; and R3 is a 1-4C lower alkyl) and 90-40 mol% constitutional units of formula (2) and having a weight average molecular weight of 8,000-25,000 and a molecular weight distribution (Mw/Mn) of <=1.5. |
