JP2004355023A - Resist composite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist composite that excels in adhesiveness to a surface with high polarity such as metal surfaces, hydrophobicity and thermal resistance and has good solvency to a solvent for a resist. <P>SOLUTION: The resist composite uses a copolymer which is obtained by polimerizing a monomer having at least an alicyclic skeleton and a monomer having a lactone skeleton and in which a copolimerization composite distribution of the monomer having the lactone skeleton in the copolymer is within -10 to +10 mol% of an average copolimerization composite of the monomer having the lactone skeleton of the whole copolymer or one which is obtained by polimerizing the monomer having the alicyclic skeleton, the monomer having the lactone skeleton, and other vinyl based monomer having higher polarity than the monomer having the alicyclic skeleton and lower polarity than the monomer having the lactone skeleton. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention has excellent adhesiveness to a highly polar surface such as a metal surface, can effectively impart hydrophobicity and heat resistance, and has good solubility in a solvent and has a low insoluble content. The present invention relates to a resist composition using coalescence.

  Conventionally, it has been known that a compound having a high polarity has good adhesion to a highly polar surface such as a metal surface due to electrostatic interaction. On the other hand, it is known that compounds having low polarity are excellent in terms of hydrophobicity, and cyclic compounds are excellent in terms of heat resistance.

  Therefore, in order to obtain a paint that has excellent adhesion to a highly polar surface such as a metal surface and can effectively impart hydrophobicity and heat resistance, it has a highly polar monomer and a low polarity cyclic structure. It has been proposed to use a binary copolymer obtained by copolymerizing a monomer as a coating resin composition.

  However, when copolymerizing monomers having such a large difference in polarity and one having a large cyclic skeleton, it is difficult to randomly copolymerize the monomers because the polymerization reactivity thereof is largely different, and it is difficult to copolymerize in the early and late stages of the polymerization. There is a tendency for a copolymer in which one of the monomer components is copolymerized in an extremely large amount. Therefore, when this copolymer is dissolved in a solvent to be used as a solvent-based paint or a resist composition, the solubility of some copolymers in which the monomer component is largely biased is poor, and the solvent-insoluble Had occurred. Then, the solvent-insoluble matter causes filter clogging in a filtration step of a paint or the like and causes poor appearance of a coating film or the like.

  Therefore, an object of the present invention is to have a highly polar monomer having excellent adhesion to a highly polar surface such as a metal surface, and a low-polarity cyclic structure that can effectively impart hydrophobicity and heat resistance. It is an object of the present invention to provide a resist composition using a copolymer obtained by copolymerizing a monomer and having a good solubility in a solvent and no insoluble matter.

  In view of the above problems, the present inventors have conducted intensive studies on the solubility of the copolymer. As a result, in the copolymer obtained from a monomer having a low-polarity cyclic structure and a monomer having a high polarity, (1) ) Keep the copolymer composition of highly polar monomers, which had been varied for each copolymer chain, within a specific range before and after the average copolymer composition of highly polar monomers in the entire copolymer. (2) adding a monomer having a specific polarity for copolymerization; and (3) producing a polymer by a specific polymerization method, so that it has good solubility in solvents such as paints and resists. The present invention has been found to be an unsuitable copolymer.

  That is, the resist composition of the present invention is a resist composition comprising a copolymer obtained by polymerizing at least a monomer having an alicyclic skeleton and a monomer having a lactone skeleton, The copolymer is such that the copolymer composition distribution of the monomer having a lactone skeleton in the copolymer is within -10 to +10 mol% of the average copolymer composition of the monomer having a lactone skeleton in the entire copolymer. It is characterized by.

  Further, the resist composition of the present invention is a resist containing a copolymer obtained by polymerizing a monomer having an alicyclic skeleton, a monomer having a lactone skeleton, and another vinyl monomer. A composition, wherein the other vinyl monomer has a higher polarity than the monomer having the alicyclic skeleton, and has a lower polarity than the monomer having the lactone skeleton. And

  Further, the resist composition of the present invention includes a copolymer obtained by polymerizing a monomer having an alicyclic skeleton and a (meth) acrylate having a substituted or unsubstituted γ-butyrolactone ring. Features.

  Further, the resist composition of the present invention is obtained by polymerizing a monomer having an alicyclic skeleton, a (meth) acrylate having a substituted or unsubstituted γ-butyrolactone ring, and another vinyl monomer. It is characterized by containing the obtained copolymer.

The resist composition of the present invention is excellent in adhesion to a highly polar surface such as a metal surface, hydrophobicity and heat resistance, and has good solubility in a resist solvent.
The resist composition of the present invention has high uniformity and is excellent in sensitivity and resolution.

Hereinafter, the present invention will be described in detail.
The present invention relates to a resist composition containing a copolymer obtained by polymerizing at least a monomer having an alicyclic skeleton and a monomer having a lactone skeleton.

The monomer having an alicyclic skeleton imparts hydrophobicity and heat resistance to a copolymer obtained by polymerizing the alicyclic skeleton and a resist composition thereof.
Examples of the monomer having such an alicyclic skeleton are not particularly limited, but include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and dicyclopentane. At least one selected from the group consisting of dienyl (meth) acrylates and their substituted products is preferably used because of its excellent hydrophobicity and heat resistance. Specific examples include 1-isobonyl methacrylate, 2-methacryloyloxy-2-methyladamantane, cyclohexyl methacrylate, adamantyl methacrylate, tricyclodecanyl methacrylate, and dicyclopentadienyl methacrylate. These can be used alone or in combination of two or more as necessary.

  Further, the monomer having an alicyclic skeleton is preferably used in a range of 10 to 90 mol%, more preferably in a range of 40 to 60 mol%, based on the whole monomer components. The monomer having an alicyclic skeleton improves the hydrophobicity and heat resistance of the obtained copolymer and its resist composition as the amount increases, and the effect of improving the adhesiveness by the monomer having a lactone skeleton described below decreases as the amount decreases. Becomes noticeable.

The monomer having a lactone skeleton imparts adhesion to a highly polar surface such as a metal surface to a copolymer obtained by polymerizing the lactone skeleton and a resist composition thereof.
The monomer having such a lactone skeleton is not particularly limited, but is a (meth) acrylate having a substituted or unsubstituted δ-valerolactone ring, a monomer having a substituted or unsubstituted γ-butyrolactone ring. At least one selected from the group consisting of is preferably used because of its excellent adhesiveness, and a monomer having an unsubstituted γ-butyrolactone ring is particularly preferably used. Specifically, β-methacryloyloxy-β-methyl-δ-valerolactone, 4,4-dimethyl-2-methylene-γ-butyrolactone, β-methacryloyloxy-γ-butyrolactone, β-methacryloyloxy-β-methyl -Γ-butyrolactone, α-methacryloyloxy-γ-butyrolactone, 2- (1-methacryloyloxy) ethyl-4-butanolide, pantoyl lactone methacrylate and the like. Examples of the monomer having a similar structure include methacryloyloxysuccinic anhydride. These can be used alone or in combination of two or more as necessary.

  Further, the monomer having a lactone skeleton is preferably used in a range of 10 to 90 mol%, more preferably in a range of 40 to 60 mol%, based on the whole monomer components. The monomer having a lactone skeleton increases the adhesion of the obtained copolymer and its resist composition as the amount increases, and the effect of improving the hydrophobicity and heat resistance of the monomer having the alicyclic skeleton increases as the amount decreases. become.

In the present invention, in addition to the monomer having an alicyclic skeleton and the monomer having a lactone skeleton, a vinyl monomer copolymerizable therewith (hereinafter, referred to as another vinyl monomer). May be used.
As other vinyl monomers, for example, (meth) acrylic acid esters having a linear or branched skeleton structure, specifically, methyl (meth) acrylate, ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , N-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (Meth) acrylate, n-propoxyethyl (meth) acrylate, i-propoxyethyl (meth) acrylate, n-butoxyethyl (meth) acrylate, i-butoxyethyl (meth) acrylate, t-butoxyethyl (meth) acrylate, etc. (Meth) acrylate Aromatic alkenyl compounds such as styrene, α-methylstyrene and vinyltoluene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and maleic anhydride; acrylamide, chloride Vinyl, ethylene and the like. These can be used alone or in combination of two or more as required.
Other vinyl monomers can be used in a range that does not impair the adhesion, water resistance, and heat resistance of the obtained copolymer, and are preferably used in an amount of 40 mol% or less based on the entire monomer components. .

In the present invention, the copolymer composition distribution of the monomer having a lactone skeleton in the copolymer is within -10 to +10 mol% of the average copolymer composition (X, unit mol%) of the monomer having a lactone skeleton. That is, the content is preferably within (X-10) to (X + 10) mol%. If the copolymer composition distribution of the monomer having a lactone skeleton in the copolymer spreads beyond this range, the solubility in a resist solvent becomes poor, and the insoluble content increases, which is not preferable.
In addition, a resist composition for semiconductor production using a copolymer in which the copolymer composition distribution of the monomer having a lactone skeleton is within -10 to +10 mol% of the average copolymer composition has high uniformity. Therefore, the sensitivity and resolution as a resist are high and excellent.

  When this copolymer is used as a resist composition for semiconductor production, the average copolymer composition of the monomer having a lactone skeleton is preferably 40 to 60 mol%. As the average copolymer composition, the larger the larger, the better the adhesion to the substrate surface and the better the resolution as a resist, and the smaller the average copolymer composition, the relatively increased the content of the monomer having an alicyclic skeleton, so that the Has improved dry etching resistance.

The following can be considered as reasons why the copolymer having a copolymer having a lactone skeleton having a copolymer composition distribution within -10 to +10 mol% of the average copolymer composition has good solubility.
A monomer having an alicyclic skeleton and a monomer having a lactone skeleton having greatly different polarities are largely different in polymerization reactivity of the respective monomers, and thus are generally difficult to be randomly copolymerized. In particular, in batch polymerization, the copolymer composition of the monomers in the copolymer obtained in the early and late stages of the polymerization (that is, depending on the conversion) is largely uneven. On the other hand, the solvent used for the resist composition is selected according to the average composition ratio of the monomers charged during the synthesis of the copolymer. For this reason, it is presumed that the copolymer in which the copolymer composition of the monomer is largely biased has poor solubility in the solvent.

The numerical value of the average copolymer composition of the monomer having a lactone skeleton of the entire copolymer in the present invention is obtained by measuring ¹ H-NMR of the copolymer and obtaining the average copolymer composition from the ratio of the specific ¹ H signal intensity obtained. Obtained by calculating the composition. The average copolymer composition obtained by the ¹ H-NMR measurement is almost the same as the ratio of the monomers charged during the production of the copolymer.

The copolymer composition distribution of the monomer having a lactone skeleton in the copolymer in the present invention is such that the copolymer composition of the monomer having a lactone skeleton for each copolymer chain is obtained by the above ¹ H-NMR measurement. It shows how much the average copolymer composition varies.
The copolymer composition distribution of the monomer having a lactone skeleton in the copolymer according to the present invention is obtained by dividing the copolymer solution into 10 to several tens fractions by gel permeation chromatography (GPC). ¹ H-NMR is measured for each fraction, and the copolymer composition of a monomer having a lactone skeleton in each fraction is determined.

  As described above, the copolymer in the present invention is a copolymer obtained by adding another vinyl monomer to a monomer having an alicyclic skeleton and a monomer having a lactone skeleton. There may be. At this time, the other vinyl monomer has a higher polarity than the monomer having an alicyclic skeleton, and has a lower polarity than the monomer having a lactone skeleton (hereinafter referred to as intermediate). Is called another vinyl monomer having the above polarity). By copolymerizing a monomer having an alicyclic skeleton, a monomer having a lactone skeleton, and another vinyl monomer having an intermediate polarity, a copolymer obtained in the early and late stages of polymerization can be obtained. Unevenness of the monomer component in the polymer can be reduced. Thereby, the solubility of the copolymer is improved, and the insoluble content in the solvent can be reduced.

  Examples of such other vinyl monomers having an intermediate polarity include (meth) acrylic esters having a linear or branched skeleton structure, and specifically, methyl (meth) acrylate, ethyl (Meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, methoxyethyl (meth) Acrylate, ethoxyethyl (meth) acrylate, n-propoxyethyl (meth) acrylate, i-propoxyethyl (meth) acrylate, n-butoxyethyl (meth) acrylate, i-butoxyethyl (meth) acrylate, t-butoxyethyl ( (Meth) acrylate and the like. These can be used alone or in combination of two or more as necessary.

  Such another vinyl monomer having an intermediate polarity is preferably used in an amount of 0 to 40 mol% based on the entire monomer components. As for the other vinyl monomers having an intermediate polarity, the solubility of the obtained copolymer increases as the amount increases, and the insoluble content decreases, and the adhesion, water resistance, and heat resistance of the obtained copolymer decrease as the amount decreases. Will be higher.

  Here, the polarity of the monomer is described in Polymer Handbook Third Edition Ed. By J. Brandrup and EH Immergut (John Wiley & Sons Inc., 1989) It is defined by the value of the polarity term (hereinafter referred to as δP value) in the equation of the solubility parameter of the liquid represented by the sum of the terms of the hydrogen bond. This δP value generally tends to increase in the order of those having an alicyclic skeleton structure, those having a linear or branched skeleton structure, and those having a lactone skeleton.

When another vinyl monomer having an intermediate polarity is used, the amount of the monomer having an alicyclic skeleton is preferably in the range of 10 to 90 mol% based on the entire monomer components. The higher the amount of the monomer having an alicyclic skeleton, the higher the hydrophobicity and heat resistance of the obtained copolymer and its resist composition, and the smaller the amount, the more the effect of improving the adhesion by the monomer having a lactone skeleton is remarkable. Become.
When another vinyl monomer having an intermediate polarity is used, the content of the monomer having a lactone skeleton is preferably in the range of 10 to 90 mol% based on the entire monomer components. The monomer having a lactone skeleton increases the adhesion of the obtained copolymer and its resist composition as the amount increases, and the effect of improving the hydrophobicity and heat resistance of the monomer having the alicyclic skeleton increases as the amount decreases. become.

  When the copolymer of the present invention is used as a resist composition for semiconductor production, the weight average molecular weight is more preferably from 1,000 to 20,000. The smaller the weight average molecular weight, the higher the sensitivity and resolution as a resist. It is more preferable that the molecular weight distribution is narrow because the sensitivity and resolution as a resist are improved. Specifically, those having a value of weight average molecular weight / number average molecular weight of 1.0 to 1.5 are preferred.

The production of the copolymer in the present invention is performed by a known polymerization method such as a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, and a bulk polymerization method. Among them, the solution polymerization method is preferable in consideration of the molecular weight of the obtained copolymer.
In general, the production of a copolymer by a solution polymerization method includes a monomer having an alicyclic skeleton and a monomer having a lactone skeleton, and in some cases, a monomer component to which another vinyl monomer is added. It is carried out by dissolving in an organic solvent, adding a polymerization initiator thereto, and heating and stirring for a certain period of time.

  In particular, as a method for producing a copolymer in the present invention, all the monomer components including a monomer having an alicyclic skeleton and a monomer having a lactone skeleton and a polymerization initiator in an organic solvent in advance A method in which the dissolved mixed solution is dropped into an organic solvent maintained at a constant temperature, that is, a so-called drop polymerization method, is preferable because the copolymer composition obtained in the early and late stages of the polymerization is not largely biased.

  The polymerization initiator used in the drop polymerization method is not particularly limited as long as it generates radicals efficiently by heat. Examples of such a polymerization initiator include azo compounds such as azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile), and organic peroxides such as benzoyl peroxide. Can be

  The solvent used in the drop polymerization method and the solvent to be dropped are a copolymerizable monomer having an alicyclic skeleton, a copolymerizable monomer having a lactone skeleton, a polymerization initiator, and the obtained copolymer. Any solvent can be used as long as it is a solvent that can be dissolved. Examples of such a solvent include alcohols such as isopropyl alcohol and butyl alcohol; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and isobutyl acetate; cellosolves such as ethyl cellosolve and butyl cellosolve; Examples thereof include ethers such as 1,4-dioxane and tetrahydrofuran.

The polymerization temperature in the drop polymerization method is determined by the boiling point of the solvent used, the decomposition temperature of the polymerization initiator used, and the like, and is not particularly limited, but is preferably in the range of 50 to 150 ° C. The higher the polymerization temperature, the shorter the reaction time and the higher the productivity, and the lower the polymerization temperature, the easier the control of the reaction.
The rate of dropping in the dropping polymerization method is not particularly limited, but is usually preferably a constant rate. The dropping time is not particularly limited, but is usually 6 hours or more, and it is preferable to maintain the temperature for about 2 hours after the completion of the dropping to complete the polymerization.

  The copolymer solution produced by the above-described production method is diluted with a good solvent such as tetrahydrofuran or 1,4-dioxane to an appropriate solution viscosity, and then dropped into a large amount of a poor solvent such as methanol or water. To precipitate. Thereafter, the precipitate is separated by filtration and dried sufficiently. This step is called "reprecipitation" and may be unnecessary in some cases, but is very effective for removing unreacted monomers or polymerization initiators remaining in the polymerization solution. If these unreacted substances remain as they are, they may adversely affect the storage stability after forming the resist and the appearance of the coating film, etc., and therefore it is preferable to remove them if possible.

The copolymer in the present invention has excellent light transmittance at 193 nm measured at a film thickness of 500 nm. For an ArF resist resin, the light transmittance of the copolymer is preferably 60% or more, more preferably 70% or more, and particularly preferably 75% or more.
Thereafter, the dried copolymer powder is dissolved in a solvent for resist. This solvent is arbitrarily selected depending on the purpose. However, the copolymer having an alicyclic skeleton and a lactone skeleton as in the present invention has very different polarities, so that it is very difficult to select a solvent. The choice of the solvent is restricted by reasons other than the solubility of the resin, for example, uniformity, appearance, safety, etc. of the coating film.

  Examples of the solvent that satisfies the above conditions when the copolymer in the present invention is used as a resist composition include ethyl lactate, propylene glycol monomethyl ether acetate, cyclohexane, diglyme, and the like.

  The resist composition of the present invention preferably contains a photoacid generator. The photoacid generator to be used is not particularly limited, and can be arbitrarily selected from those usable as a photoacid generator of the chemically amplified resist composition. Specific examples include an onium salt compound, a sulfonimide compound, a sulfone compound, a sulfonate compound, a quinonediazide compound, and a diazomethane compound. Of these, onium salt compounds are preferred, and examples thereof include sulfonium salts, iodonium salts, phosphonium salts, diazonium salts, and pyridinium salts. Specific examples include triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium naphthalene sulfonate, (hydroxyphenyl) benzylmethylsulfonium toluenesulfonate, diphenyliodonium triflate, diphenyliodonium pyrene sulfonate, diphenyliodonium dodecylbenzenesulfonate And diphenyliodonium hexafluoroantimonate.

  In the present invention, the photoacid generators can be used alone or in combination of two or more. The amount of the photoacid generator used in the present invention is appropriately selected depending on the kind of the selected photoacid generator, but is usually 0.1 to 20 parts by weight, particularly preferably 0.5 to 100 parts by weight, per 100 parts by weight of the copolymer. -10 parts by weight. The larger the amount of the photoacid generator used, the more the chemical reaction due to the catalytic action of the acid generated by exposure can occur, and the smaller the amount, the less uneven coating when applying the composition and scum during development. Less.

It is preferable that the resist composition of the present invention contains a basic substance. As such a basic substance, a nitrogen-containing heterocyclic compound and / or an amide group-containing compound are particularly preferable.
Specific examples of the nitrogen-containing heterocyclic compound include imidazoles such as imidazole, benzimidazole, 4-methylimidazole and 4-methyl-2-phenylimidazole; pyridine, 2-methylpyridine, 4-methylpyridine and 2-ethylpyridine Pyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, N-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 8-oxyquinoline, acridine and the like , Pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, morpholine, 4-methylmorpholine, piperazine, 1,4-dimethylpiperazine, tetrazole, 1,4-diazabicyclo [2.2.2] octane and the like. . Among them, tetrazoles, diazabicyclooctanes, and piperidines are more preferable.

  Specific examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, N-cyclohexylformamide, acetamido, N-methylacetamido, N, N-dimethylacetamido, N- (1-adamantyl) Acetamide, propionamide, benzamide, N-acetylethanolamine, 1-acetyl-3-methylpiperidine, or pyrrolidone, N-methylpyrrolidone, 1-cyclohexyl-2-pyrrolidone, ε-caprolactam, δ-valerolactam, Cyclic amides such as -pyrrolidinone, or acrylamide, methacrylamide, t-butylacrylamide, N-isopropylmethacrylamide, methylenebisacrylamide, methylenebismethacrylamide, N-methylo And acrylamides such as acrylacrylamide, N-methylolmethacrylamide, N-methoxyacrylamide, N-ethoxyacrylamide, N-butoxyacrylamide and diacetoneacrylamide. Among them, (meth) acrylamides and acetamides are more preferable.

The basic substances can be used alone or in combination of two or more. The amount of the basic substance used is appropriately selected depending on the type of the selected basic substance, but is usually 0.01 to 10 mol, preferably 0.05 to 1 mol, per mol of the photoacid generator. Is a mole. The larger the amount of the basic substance used, the better the resist shape, and the smaller the amount, the better the sensitivity as a resist and the improved the developability of the exposed portion.
Further, various additives such as a surfactant, a sensitizer, an antihalation agent, a storage stabilizer and an antifoaming agent can be added to the chemically amplified resist composition of the present invention, if necessary.

  Hereinafter, the present invention will be specifically described based on examples. Here, “parts” means “parts by weight” unless otherwise specified.

The measurement of the physical properties of the copolymer was performed using the following methods.
-Weight average molecular weight It was determined by gel permeation chromatography (GPC) in terms of polymethyl methacrylate. Chloroform was used as the solvent.
・ Average copolymer composition of monomer having lactone skeleton (mol%)
^It was determined by ¹ H-NMR measurement. Heavy chloroform was used as the solvent.
-Copolymer composition distribution of a monomer having a lactone skeleton The copolymer was dissolved in chloroform, this solution was fractionated into 10 fractions by GPC, and ¹ H-NMR was measured for each fraction. The copolymer composition of the monomer having a lactone skeleton in the polymer was determined. The one having the highest copolymer composition of the monomer having the lactone skeleton was defined as the maximum composition (mol%), and the one having the lowest copolymer composition of the monomer having the lactone skeleton was determined as the minimum composition (mol%). .

-Solubility 1 part of the copolymer was added to 7 parts each of ethyl lactate and propylene glycol monomethyl ether acetate, and the mixture was stirred at room temperature for 2 hours, and the state of the solution was observed. In the judgment, "O" means that there was no insoluble matter and the solution was transparent, and "X" means that there was insoluble matter and the solution was opaque.
-Light transmittance The sample copolymer is coated on a silicon substrate at a thickness (d) of 500 nm, and the complex refractive index (refractive index n and extinction coefficient k) of the copolymer is measured using a spectroscopic ellipsometer. , At an exposure wavelength (λ) of 193 nm. From these measurement conditions and measurement results, the transmittance (I / I ₀ ) is calculated by the following equation. (However, when the transmittance is expressed in%, I / I ₀ is multiplied by 100.)
I / I ₀ = exp (-4πdk / λ)

(Example 1)
Under a nitrogen atmosphere, 20.0 parts of 1,4-dioxane was charged into a flask equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer, and the temperature of the hot water bath was raised to 80 ° C. while stirring. 27.8 parts of 1-isobonyl methacrylate (50 mol% based on all components of monomer), 24.8 parts of β-methacryloyloxy-β-methyl-δ-valerolactone (50% based on all components of monomer) Mol%), 62.5 parts of 1,4-dioxane and 1.9 parts of azobisisobutyronitrile were dropped into the flask at a constant speed over a period of 6 hours. Was maintained for 2 hours. Next, the obtained reaction solution was diluted about 2-fold with tetrahydrofuran, and added dropwise to about 10-fold amount of methanol while stirring to obtain a white precipitate (copolymer A). The obtained precipitate was separated by filtration, dried at 60 ° C. under reduced pressure for about 40 hours, and the results of measuring the properties of the copolymer A are shown in Table 1.

(Examples 2 to 8)
Copolymers B to H were obtained in the same manner as in Example 1, except that the total number of moles of the monomers was not changed and the monomers and the amounts thereof were changed as shown in Table 1. Table 1 shows the results of measuring the properties of the obtained copolymers B to H.

(Example 9)
In a flask equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer, under a nitrogen atmosphere, 22.8 parts of 1-isobonyl methacrylate (41 mol% based on all components of the monomer), β-methacryloyloxy-β -Methyl-δ-valerolactone 20.3 parts (41 mol% based on all monomers), methyl methacrylate 4.5 parts (18 mol% based on all monomers), 1,4-dioxane A total of 82.5 parts and 3.8 parts of azobisisobutyronitrile were added, the temperature of the hot water bath was raised to 80 ° C. with stirring, and polymerization was carried out at that temperature for 8 hours. Next, the obtained reaction solution was diluted about 2-fold with tetrahydrofuran, and added dropwise to about 10-fold amount of methanol while stirring to obtain a white precipitate (copolymer I). The obtained precipitate was separated by filtration, dried at 60 ° C. under reduced pressure for about 40 hours, and the results of measuring each property of Copolymer I are shown in Table 2.

(Examples 10 to 14)
Copolymers J to N were obtained in the same manner as in Example 9 except that the total mole number of the monomers was not changed and the monomers and the proportions thereof were changed as shown in Table 2. Table 2 shows the results obtained by measuring the properties of the obtained copolymers J to N.

(Comparative Example 1)
In a flask equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer, under a nitrogen atmosphere, 27.8 parts of 1-isobornyl methacrylate, 24.8 parts of β-methacryloyloxy-β-methyl-δ-valerolactone, , 4-Dioxane (82.5 parts) and azobisisobutyronitrile (3.8 parts) were all added, the temperature of the hot water bath was raised to 80 ° C. while stirring, and polymerization was carried out at that temperature for 8 hours. Next, the obtained reaction solution was diluted about 2-fold with tetrahydrofuran, and added dropwise to about 10-fold amount of methanol while stirring to obtain a white precipitate (copolymer O). The obtained precipitate was separated by filtration, dried under reduced pressure at 60 ° C. for about 40 hours, and the results of measuring each physical property of the copolymer O are shown in Table 3.

(Comparative Examples 2 to 6)
Copolymers P to T were obtained in the same manner as in Comparative Example 1, except that the total number of moles of the monomer was not changed and the amount of the monomer and the amount thereof were changed as shown in Table 3. Table 3 shows the results of measuring the properties of the obtained copolymers P to T.

The resist composition for manufacturing a semiconductor of the present invention has high uniformity and is excellent in sensitivity and resolution. Further, the copolymer in the present invention has excellent transparency to an ArF excimer laser (wavelength: 193 nm), and thus is excellent as a resin for ArF resist.

Claims (4)

A resist composition comprising a copolymer obtained by polymerizing at least a monomer having an alicyclic skeleton and a monomer having a lactone skeleton,
In the copolymer, the copolymer composition distribution of the monomer having a lactone skeleton in the copolymer is within -10 to +10 mol% of the average copolymer composition of the monomer having a lactone skeleton in the entire copolymer. A resist composition comprising: A monomer having an alicyclic skeleton, a monomer having a lactone skeleton, and a resist composition containing a copolymer obtained by polymerizing another vinyl monomer,
The resist composition, wherein the other vinyl monomer has a higher polarity than the monomer having the alicyclic skeleton, and has a lower polarity than the monomer having the lactone skeleton. . A resist composition comprising a copolymer obtained by polymerizing a monomer having an alicyclic skeleton and a (meth) acrylate having a substituted or unsubstituted γ-butyrolactone ring. It is characterized by containing a copolymer obtained by polymerizing a monomer having an alicyclic skeleton, a (meth) acrylate having a substituted or unsubstituted γ-butyrolactone ring, and another vinyl monomer. Resist composition.