| 摘要 |
<p>PROBLEM TO BE SOLVED: To produce a narrowly distributed polystyrene polymer suitable as a resin material for resist and to obtain a chemical amplification-type positive resist composition having excellent sensitivity and resolution by using the narrowly distributed polystyrene polymer. SOLUTION: A styrene derivative of the formula (R is a 1-12C alkyl or a 1-12C alkanoyl) is subjected to radical polymerization in a living state in the presence of a free-radical initiator and a nitrogen-containing stable free-radical active agent, a terminator is added after the polymerization have proceeded until the objective molecular weight, and the free-radical active agent bound to the polymer terminal is removed with the result that the objective narrowly distributed polystyrene is obtained. In the obtained polystyrene, the group corresponding to the R is removed to convert the OR part to a hydroxy group, and the hydroxy group is partly protected with an unstable group against an acid, and as a result, a copolymer having a p-hydroxystyrene unit and the unit which is formed by protecting the hydroxy group of the p-hydroxystyrene unit with the unstable group against an acid is obtained. A positive-type resist composition having the copolymer as a resin component is also provided.</p> |
