Thiol compound, copolymer and method for producing the copolymer
By resolving objections in the prior art, provided are a novel copolymer suitable as a coating polymers which is excellent in adhesion to a substrate and can be used suitably as the polymer for the coating film having durability against pattern collapse in the finer pattern formation for progressed lithography technology and a method for producing the copolymer, as well as a novel thiol compound useful as a chain transfer agent in the production of the copolymer. The novel thiol compound of the present invention has the structure represented by the formula (1); wherein R 1 is a bivalent substituent selected from linear, branched or cyclic saturated hydrocarbon having 1 to 15 carbon atoms.
1. A copolymer obtained by using a thiol compound represented by the formula (1);
(wherein R 1 is a bivalent substituent selected from linear, branched or cyclic saturated hydrocarbon having 1 to 15 carbon atoms.) as a chain transfer agent, in polymerization of two or more polymerizable compounds having an ethylenic double bond.
2. The copolymer according to claim 1 comprising a structure represented by the formula (2);
(wherein R 1 is a bivalent substituent selected from linear, branched or cyclic saturated hydrocarbon having 1 to 15 carbon atoms.) as the end group.
3. The copolymer according to claim 1 used as a coating polymer in semiconductor lithography.
4. The copolymer according to claim 3 , which has at least a repeating unit having a structure which is decomposed by an acid to become soluble in an alkali developer and a repeating unit having a polar group to enhance adhesion to a substrate, and which is used as a resist polymer.
5. The copolymer according to claim 3 which is used as an anti-reflective coating polymer coated under the resist film.