Copolymer and composition for semiconductor lithography and process for producing the copolymer

摘要

[Task to Be Achieved];To provide a chemically amplified type positive copolymer for semiconductor lithography, which has eliminated the problems of prior art, has a high development contrast, and has excellent resolution in fine-pattern formation; a composition for semiconductor lithography which contains the copolymer; and a process for producing the copolymer.;[Means for Achievement];The copolymer for semiconductor lithography according to the present invention is a copolymer which has at least (A) a repeating unit having a structure which has an alkali-soluble group protected by an acid-labile, dissolution-suppressing group, (B) a repeating group having a lactone structure and (C) a repeating group having an alcoholic hydroxyl group and which is characterized by having an acid value of 0.01 mmol/g or less as determined by dissolving the copolymer in a solvent and subjecting the solution to neutralization titration with a solution of an alkali metal hydroxide using Bromothymol Blue as an indicator.

主权项

1. A process for producing a copolymer for semiconductor lithography, having at least (A) a repeating unit having a structure which has an alkali-soluble group protected by an acid-labile, dissolution-suppressing group, (B) a repeating roup unit having a lactone structure and (C) a repeating unit having an alcoholic hydroxyl group, which process being characterized by dissolving at least one monomer of a monomer giving the repeating unit (A) in an organic solvent to produce a first solution, dissolving at least one monomer of a monomer giving the repeating unit (B) in the organic solvent to produce a second solution, dissolving at least one monomer of a monomer giving the repeating unit (C) in the organic solvent to produce a third solution, contacting each of the resulting solutions with water followed by giving rise to phase separation, and, thereafter, copolymerizing the monomers, and the copolymer being characterized by having an acid value of 0.01 mmol/g or less as determined by dissolving the copolymer in a solvent and subjecting the solution to neutralization titration with a solution of an alkali metal hydroxide using Bromothymol Blue as an indicator,
wherein the acid-labile, dissolution-suppressing group of the repeating unit (A) is selected from a structure represented by the following formula (L2) {in the formula (L2), o is a bonding site of the acid-labile, dissolution-suppressing group, R16 and R17 are each independently a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, R18 is a hydrocarbon group having 1 to 12 carbon atoms, and R16 may bond with R17 or R18 to form a ring}.