Abstract: [Problem] To provide a method capable of efficiently mass-producing a polymer solution which is useful for preparation of a resist composition for thick films, which has a high polymer concentration and which contains a plurality of solvents at a desired ratio. [Solution] A method for producing a polymer solution containing C % by mass of a polymer in a mixed solvent of at least two or more solvents mixed at a predetermined mass ratio, in which an objective polymer solution is produced by estimating the polymer concentration and the solvent composition ratio of a “prepolymer solution” in which the solvent composition ratio in condensation of a polymer solution containing all the solvents, to an objective concentration C % by mass, is also just a predetermined value, thereby preparing and then condensing the prepolymer solution.

Abstract: Provided are a 4-hydroxystyrene solution with high purity and good storage stability that is suitable as a source for producing a 4-hydroxystyrene polymer on a commercial scale, and a method of producing the solution. The method of producing a 4-hydroxystyrene solution of the present invention includes the following steps (i) to (iv): (i) deprotection step for contacting 4-acetoxystyrene with a base in a solvent to produce 4-hydroxystyrene; (ii) neutralization step for adding an acid to the solution containing 4-hydroxystyrene after deprotection to neutralize the solution; (iii) step for washing the solution containing 4-hydroxystyrene after neutralization with water; and (iv) solvent replacement step for adding a solvent that can dissolve 4-hydroxystyrene to the solution containing 4-hydroxystyrene followed by distillation at 40° C. or lower to remove other components than 4-hydroxystyrene and excess solvent.

Abstract: A method is provided for purifying a resin for photolithography wherein, from an insufficiently purified resin (also referred to as “crude resin”), low molecular weight impurities such as an unreacted monomer and a polymerization initiator, which cause a development defect of a resist pattern or deterioration of the storage stability of the resin for photolithography can be removed more effectively. The method for purifying a resin for photolithography includes an operation (a) wherein a slurry in which a resin is dispersed in a solution containing a good solvent and a poor solvent is stirred, and then an operation (b) wherein, to said slurry, a poor solvent is added to lower the ratio of the good solvent to the poor solvent, and then, the resin is separated from the solution.

Abstract: [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.

Abstract: A method for producing a resist copolymer having a weight-average molecular weight of not less than 3000 and not more than 6000, in which copolymer the contents of an oligomer having a molecular weight of not more than 1000 and a byproduct derived from a polymerization initiator are small, is provided. The method for producing a resist copolymer comprises the step of continuously supplying a solution containing a monomer and a solution containing a polymerization initiator to a heated solvent to carry out a radical polymerization, wherein the variation range of the concentration of the polymerization initiator in polymerization solution is within ±25% of the median value between the maximum concentration and the minimum concentration during specific time; and the variation range of the concentration of unreacted monomer in the polymerization solution is within ±35% of the median value between the maximum concentration and the minimum concentration during specific time.

Abstract: Provided is a method for purifying a resin for photolithography wherein, from an insufficiently purified resin (also referred to as “crude resin”), low molecular weight impurities such as an unreacted monomer and a polymerization initiator, which cause a development defect of a resist pattern or deterioration of the storage stability of the resin for photolithography can be removed more effectively. A method for purifying a resin for photolithography according to the present invention is characterized by comprising: an operation (a): an operation wherein a slurry in which a resin is dispersed in a solution containing a good solvent and a poor solvent is stirred; and then, an operation (b): an operation wherein, to said slurry, a poor solvent is added to lower the ratio of the good solvent to the poor solvent, and then, the resin is separated from the solution.

Abstract: The present invention provides a method for production of a copolymer for photoresists in which the bias of the monomer composition ration is small. This method for production is a method for production of a copolymer for photoresists, which copolymer containing at least two types of repeating units, the method having a supplying step of supplying a monomer solution and a solution containing a polymerization initiator into a polymerization reaction system, wherein the range of fluctuation of the monomer composition ratio of unreacted monomers is within the range between minus 15% and plus 15% or the standard deviation of the monomer composition ratio of unreacted monomers is within 2 in the polymerization reaction system during the period from the start of the polymerization reaction to the end of supplying of the monomer solution.

Abstract: The present invention provides a copolymer which can prevent problems associated with immersion lithography (including occurrence of a pattern defect such as water mark, and variation in sensitivity or abnormal patterning due to elution of an additive such as a radiation-sensitive acid-generator) and which provides surface characteristics suitable for immersion lithography, and a composition containing the copolymer.

Abstract: Solving problems in the prior art, provided are a resist polymer which is small in lot-to-lot, reactor-to-reactor and scale-to-scale variations, and contains no high polymer, is excellent in solubility and storage stability, and is suitable for fine pattern formation, and a method for production thereof. The present invention provides the resist polymer at least having 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, characterized in that a peak area of a high molecular weight component (high polymer) with molecular weight of 100,000 or more is 0.1% or less based on an entire peak area in a molecular weight distribution determined, by gel permeation chromatography (GPC).

Abstract: Provided are a positive resist composition and a resist pattern forming method having fewer defects and superior lithographic characteristics. The positive resist composition includes a resin component (A) which has on a main chain a structural unit derived from an (?-lower alkyl)acrylate ester and exhibits increased alkali solubility under the action of an acid, and an acid generating component (B) which generates the acid upon irradiation with radiation, in which the resin component (A) is a copolymer having at least two structural units which is obtained by incorporating an acid when polymerizing at least one monomer for the production thereof.

Abstract: The present invention provides a method for production of a copolymer for photoresists in which the bias of the monomer composition ration is small. This method for production is a method for production of a copolymer for photoresists, which copolymer containing at least two types of repeating units, the method having a supplying step of supplying a monomer solution and a solution containing a polymerization initiator into a polymerization reaction system, wherein the range of fluctuation of the monomer composition ratio of unreacted monomers is within the range between minus 15% and plus 15% or the standard deviation of the monomer composition ratio of unreacted monomers is within 2 in the polymerization reaction system during the period from the start of the polymerization reaction to the end of supplying of the monomer solution.

Abstract: A copolymer for semiconductor lithography, comprising at least a recurring unit (A) having a carboxylic acid ester structure whose solubility in alkali increases by the action of an acid and a carboxyl group-containing recurring unit (B), which copolymer is obtained via a step (P) of (co)polymerizing at least a monomer giving a recurring unit (A) and a step (Q) of forming a recurring unit (B) in the co-presence of a recurring unit (A)-containing (co)polymer and/or a monomer giving a recurring unit (A), and an acid. The copolymer is used in production of semiconductor as a resist polymer which is small in roughness, little in development defect and superior in lithography properties such as DOF and the like.

Abstract: [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.

Abstract: The present invention provides a copolymer which can prevent problems associated with immersion lithography (including occurrence of a pattern defect such as water mark, and variation in sensitivity or abnormal patterning due to elution of an additive such as a radiation-sensitive acid-generator) and which provides surface characteristics suitable for immersion lithography, and a composition containing the copolymer.

Abstract: Provided are a positive resist composition and a resist pattern forming method having fewer defects and superior lithographic characteristics. The positive resist composition includes a resin component (A) which has on a main chain a structural unit derived from an (?-lower alkyl)acrylate ester and exhibits increased alkali solubility under the action of an acid, and an acid generating component (B) which generates the acid upon irradiation with radiation, in which the resin component (A) is a copolymer having at least two structural units which is obtained by incorporating an acid when polymerizing at least one monomer for the production thereof.

Abstract: Solving problems in the prior art, provided are a resist polymer which is small in lot-to-lot, reactor-to-reactor and scale-to-scale variations, and contains no high polymer, is excellent in solubility and storage stability, and is suitable for fine pattern formation, and a method for production thereof. The present invention provides the resist polymer at least having 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, characterized in that a peak area of a high molecular weight component (high polymer) with molecular weight of 100,000 or more is 0.1% or less based on an entire peak area in a molecular weight distribution determined, by gel permeation chromatography (GPC).

Abstract: A copolymer for semiconductor lithography, comprising at least a recurring unit (A) having a carboxylic acid ester structure whose solubility in alkali increases by the action of an acid and a carboxyl group-containing recurring unit (B), which copolymer is obtained via a step (P) of (co)polymerizing at least a monomer giving a recurring unit (A) and a step (Q) of forming a recurring unit (B) in the co-presence of a recurring unit (A)-containing (co)polymer and/or a monomer giving a recurring unit (A), and an acid. The copolymer is used in production of semiconductor as a resist polymer which is small in roughness, little in development defect and superior in lithography properties such as DOF and the like.

Abstract: Provided are a preparation process of a copolymer for semiconductor lithography, suited for a film forming composition used for the formation of minute patterns necessary for semiconductor fabrication, which comprises carrying out radical polymerization of at least two monomers having an ethylenic double bond in the presence of a polymerization initiator in a polymerization solvent, while causing to exist, in the solution containing the monomers, a polymerization inhibitive component; and a copolymer for semiconductor lithography prepared by the above-described process, and contains no high polymer, has excellent storage stability and generates remarkably less defects in resist pattern when used for semiconductor lithography.

Abstract: Solving problems in the prior art, provided are a resist polymer which is small in lot-to-lot, reactor-to-reactor and scale-to-scale variations, and contains no high polymer, is excellent in solubility and storage stability, and is suitable for fine pattern formation, and a method for production thereof. The present invention provides the resist polymer at least having 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, characterized in that a peak area of a high molecular weight component (high polymer) with molecular weight of 100,000 or more is 0.1% or less based on an entire peak area in a molecular weight distribution determined by gel permeation chromatography (GPC).

Abstract: Provided are a preparation process of a copolymer for semiconductor lithography, suited for a film forming composition used for the formation of minute patterns necessary for semiconductor fabrication, which comprises carrying out radical polymerization of at least two monomers having an ethylenic double bond in the presence of a polymerization initiator in a polymerization solvent, while causing to exist, in the solution containing the monomers, a polymerization inhibitive component; and a copolymer for semiconductor lithography prepared by the above-described process, and contains no high polymer, has excellent storage stability and generates remarkably less defects in resist pattern when used for semiconductor lithography.