JP4332445B2 - Resist polymer - Google Patents

Description

  The present invention relates to a resist polymer, a resist composition, and a pattern manufacturing method, and more particularly to a chemically amplified resist composition suitable for fine processing using an excimer laser, an electron beam, and an X-ray.

  In recent years, in the field of microfabrication in the manufacture of semiconductor elements and liquid crystal elements, miniaturization has rapidly progressed due to advances in lithography technology. As a method for miniaturization, generally, a shorter wavelength of irradiation light is used. Specifically, from conventional ultraviolet rays typified by g-line (wavelength: 438 nm) and i-line (wavelength: 365 nm) to DUV ( The irradiation light is changing to Deep Ultra Violet.

At present, KrF excimer laser (wavelength: 248 nm) lithography technology is introduced into the market, and ArF excimer laser (wavelength: 193 nm) lithography technology for further shortening the wavelength is about to be introduced. Further, as a next-generation technique, an F ₂ excimer laser (wavelength: 157 nm) lithography technique has been studied. In addition, as a slightly different type of lithography technology, an electron beam lithography technology and an EUV lithography technology have been energetically studied.

  As a high-resolution resist for such short-wavelength irradiation light or electron beam, a “chemically amplified resist” containing a photoacid generator has been proposed. At present, improvements and development of this chemically amplified resist are energetically active. It is being advanced.

  As a resist resin used in ArF excimer laser lithography, an acrylic resin that is transparent with respect to light having a wavelength of 193 nm has attracted attention. Examples of such acrylic resins include copolymers of (meth) acrylic acid ester having an adamantane skeleton in the ester portion and (meth) acrylic acid ester having a lactone skeleton in the ester portion. Etc. are disclosed.

  However, when these acrylic resins are used as a resist resin, the resin contained in the resist composition aggregates with time to generate an insoluble matter called a microgel, and the resist pattern is missing. Circuit breaks or defects may occur. In addition, an insoluble matter called a defect is generated during development, and the resist pattern is lost, which may cause a circuit disconnection or a defect.

On the other hand, a chemically amplified resist composition containing a resin containing a structural unit having a cyano group is disclosed in, for example, Patent Literature 3, Patent Literature 4, Patent Literature 5, Patent Literature 6, and the like. In Patent Document 3, a cyano group is mentioned as a substituent of an alicyclic hydrocarbon group contained in a group (acid dissociable group) that is eliminated by an acid in a resin. Patent Document 4 describes that a cyano group-containing polymer unit ensures adhesion to a substrate and contributes to improvement of resist dry etching resistance by the presence of a cyano group that is a polar substituent. Patent Document 5 describes that line edge roughness can be improved by using a resin containing a specific structural unit having a cyano group. Patent Document 6 describes that by using a resin as a specific structural unit having a cyano group, the transmittance with respect to 157 nm which is the wavelength of F ₂ excimer laser can be improved.

  Patent Document 7 discloses an alicyclic compound having a cyano group as a substituent as an acrylic monomer that is a raw material of a polymer useful as an optical material having excellent optical properties, low hygroscopicity, and heat resistance. A (meth) acrylic acid ester derivative having a skeleton is disclosed. Patent Document 7 discloses that this (meth) acrylic acid ester-based derivative can be used alone or as a copolymer with it and other unsaturated compounds such as (meth) acrylic acid and its ester. Are listed.

Furthermore, in Patent Document 8, as a resist composition excellent in sensitivity and resolution used in ArF excimer laser (wavelength: 193 nm) lithography, a structural unit having a group containing a polar moiety and a group capable of leaving by an acid. A resist composition containing a (meth) acrylic copolymer containing a structural unit having a photoacid generator and a cyano group, a lactone as one of the polar parts (polar groups) Are listed. Examples of Patent Document 8 include a polymer obtained by polymerizing 5- (4-) cyano-2-norbornyl methacrylate, 2′-acetoxyethyl methacrylate, 1-butyl methacrylate and methacrylic acid (Example 4) and , 5- (4-) cyano-2-norbornyl methacrylate, t-butyl methacrylate and a polymer obtained by polymerizing methacrylic acid (Example 6). However, when these polymers are used in a resist composition for ArF excimer laser lithography, there is a problem in solubility in a resist solvent and a developer, and thus there is a problem that microgels and defects occur. .
JP 10-319595 A JP-A-10-274852 JP 2002-244295 A JP 2000-258915 A JP 2002-268222 A JP 2001-264882 A Japanese Patent Laid-Open No. 1-110035 US Pat. No. 6,165,678

  The present invention relates to a resist polymer, a resist composition, and a resist composition, which have a small line edge roughness and little generation of microgel and defects when used as a resist resin in DUV excimer laser lithography or electron beam lithography. An object of the present invention is to provide a pattern manufacturing method using an object.

  As a result of intensive studies in view of the above problems, the present inventors have found that in DUV excimer laser lithography or electron beam lithography, a structural unit having a specific cyano group-containing alicyclic structure and a structural unit containing an ether structure or an acetal structure It has been found that the use of a polymer containing a polymer in a resist composition improves the solubility without impairing high sensitivity and high resolution, suppresses the formation of defects and microgels, and reduces the line edge roughness. The present invention has been reached.

The first gist of the present invention is represented by a structural unit having a cyano group-containing alicyclic structure represented by the following formula (2) , and the following formulas (1b ′), (1c), and (1d). And at least one structural unit selected from the group consisting of structural units, and the proportion of the structural units having the cyano group-containing alicyclic structure is 5 mol% or more and 40 mol% with respect to the total monomers. The ratio of at least one structural unit selected from the group consisting of structural units represented by the formulas (1b ′), (1c) and (1d) is 30 mol% based on the total amount of all monomers. It is a resist polymer having a weight average molecular weight of 1,000 or more and 100,000 or less .

(In formula (2), R ⁰¹ Represents a hydrogen atom or a methyl group. )

(Wherein R ⁰⁸ Represents a hydrogen atom or a methyl group, and m represents 1 or 2. )

(In the formula (1c), R ⁰⁶ represents a hydrogen atom or a methyl group. M1 is an integer of 0 to 3.)

(In the formula (1d), R ⁰⁷ represents a hydrogen atom or a methyl group. M2 is an integer of 0 to 3.)
In the formula (1b), the alkyl group having 1 to 12 carbon atoms includes not only a chain group but also a cyclic group such as cyclohexane, cyclopentane, and adamantane. Moreover, the said ring means what substituted one carbon atom of the ring like oxygen, such as cyclohexane, cyclopentane, and adamantane.

The resist polymer of the present invention has a high sensitivity and high resolution when used as a resist resin in DUV excimer laser lithography, electron beam lithography, etc., without impairing high sensitivity and high resolution. In addition, the production of microgel is also suppressed, and the line edge roughness is small.

1. Structural Unit of Resist Polymer of the Present Invention In the present invention, the alicyclic skeleton means a structure having one or more cyclic hydrocarbon groups. “(Meth) acrylic acid” is a general term for acrylic acid and methacrylic acid.

Among the structural units represented by the above formula (1), structural units represented by the following formula (2) and the following formula (1-1) are preferable.

(In the formula (2), R ⁰¹ represents a hydrogen atom or a methyl group.)
In this polymer, the structural units represented by the formula (2) need not all be the same, and two or more types may be mixed.

(In the formula (1-1), R ⁰¹ represents a hydrogen atom or a methyl group, R ⁰³ represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms. A ⁰¹ and A ⁰² are each independently Represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, or A ⁰¹ and A ⁰² are combined to form —O—, —S—, —NH—, or 1 to 6 carbon atoms; Represents an alkylene chain.)
In this polymer, all the structural units represented by the formula (1-1) do not have to be the same, and two or more types may be mixed.

The structural unit represented by the formula (1) of the resist polymer of the present invention is derived from a (meth) acrylic acid ester derivative represented by the following formula (5). The (meth) acrylic acid ester derivative represented by the following formula (5) may be one type or a mixture of two or more types.

(In the formula (5), R ⁰¹ , R ⁰² , Z, and p have the same meanings as in the formula (1).)
In the formula (5), R ⁰² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The alkyl group may be linear or branched. Examples of such an alkyl group include a methyl group, an ethyl group, a propyl group, and an isopropyl group. R ⁰² is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom, from the viewpoint of solubility in an organic solvent.

In the formula (5), Z represents an atomic group constituting a cyclic hydrocarbon group, preferably a bridged cyclic hydrocarbon group, together with a carbon atom having an ester bond and a carbon atom having a cyano group bonded thereto. Although carbon number of a cyclic hydrocarbon group is not specifically limited, 7-20 are preferable. This cyclic hydrocarbon group may have a substituent in addition to the cyano group. Examples of the substituent include a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and an amino group. A linear or branched alkyl group having 1 to 6 carbon atoms which may have at least one group selected from the group, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy having 1 to 6 carbon atoms Group, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, an amino group, and the like.

Examples of Z in the formula (5) include cyclic terpene hydrocarbons such as norbornane ring, adamantane ring, tetracyclododecane ring, dicyclopentane ring, tricyclodecane ring, decahydronaphthalene ring, polyhydroanthracene ring, An atomic group having a camphor ring, a cholesteric ring, or the like can be given. Z is an atomic group having a cyclic terpene hydrocarbon such as a norbornane ring, an adamantane ring, a tetracyclododecane ring, a dicyclopentane ring or a tricyclodecane ring because it has a high dry etching resistance required for a resist. Preferably, an atomic group having a norbornane ring represented by the following formula (11-1), a tetracyclododecane ring represented by the following formula (11-2), or an adamantane ring represented by the following formula (11-3) More preferred. Among these, an atomic group having a norbornane ring is particularly preferable from the viewpoint of excellent copolymerizability with other monomers.

  In formula (5), p represents the number of cyano groups that the cyclic hydrocarbon group has, and is an integer of 1 to 4. p is preferably 1 or 2 and more preferably 1 in terms of sensitivity and resolution.

  When p is 2 or more, the cyano group may be bonded to the same carbon atom, or may be bonded to different carbon atoms, but bonded to different carbon atoms from the viewpoint of adhesion to a metal surface or the like. It is preferable.

  The substitution position of the cyano group is not particularly limited. For example, when Z is a norbornyl ring, if the 5-position is substituted with a (meth) acryloyl group, the substitution position of the cyano group is the 2-position and / or 3-position. It is preferable.

Specific examples of the monomer represented by the above formula (5) include monomers represented by the following formulas (6-1) to (6-16). In formulas (6-1) to (6-16), R represents a hydrogen atom or a methyl group.

  As the monomer represented by the above formula (5), the monomer represented by the above formula (6-1) and the above formula (6-3) are particularly preferable from the viewpoint of dry etching resistance. A monomer, a monomer represented by the above formula (6-4), a monomer represented by the above formula (6-6) are preferable, and a monomer represented by the above formula (6-1) , The monomer represented by the above formula (6-4) and the monomer represented by the above formula (6-6) are more preferable, and from the viewpoint of excellent copolymerizability with other monomers, A monomer represented by the formula (6-1) is particularly preferable.

The structural unit represented by the formula (1-1) is derived from a (meth) acrylic acid ester derivative having a cyano group represented by the following formula (5-1). That is, the resist polymer of the present invention is obtained by copolymerizing a monomer composition containing a (meth) acrylic acid ester derivative having a cyano group represented by the following formula (5-1). The (meth) acrylic acid ester derivative represented by the following formula (5-1) may be one type or a mixture of two or more types.

(In formula (5-1), R ⁰¹ , R ⁰³ , A ⁰¹ , and A ⁰² have the same ^{meanings as} in formula (5).)
In formula (5-1), R ⁰³ represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms. R ⁰³ is preferably an ethyl group, a methyl group, or a hydrogen atom, and more preferably a methyl group, from the viewpoint of excellent copolymerizability with other monomers.

In formula (5-1), A ⁰¹ and A ⁰² each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, or A ⁰¹ and A ⁰² together O-, -S-, -NH- or an alkylene chain having 1 to 6 carbon atoms is represented. The A ⁰¹ and A ^02, from the viewpoint of excellent solubility in solvents, it is preferred that the the A ⁰¹ and A ⁰² are both hydrogen atoms, from the viewpoint of excellent dry etching resistance, together with A ⁰¹ and A ⁰² To form —CH ₂ — or —CH ₂ —CH ₂ —.

Specific examples of the monomer represented by the above formula (5-1) include monomers represented by the following formulas (6-17) to (6-18). In formulas (6-17) to (6-18), R represents a hydrogen atom or a methyl group.

Such a cyano group-containing (meth) acrylic acid ester derivative represented by the above formula (5) can be produced, for example, by the following step (I) or (II). The following step (I) shows a production process of the monomer represented by the above formula (6-1), and the following step (II) is a monomer represented by the above formula (6-17). However, other monomers represented by the above formula (5) can also be produced in the same manner.

  The raw materials (meth) acrylonitrile, cyclopentadiene, 2-methoxybutadiene, (meth) acrylic acid and derivatives thereof can be produced by known methods, and commercially available products can also be used.

  Cycloaddition reaction of (meth) acrylonitrile and cyclopentadiene or 2-methoxybutadiene proceeds easily by a known method, but if necessary, a catalyst such as Lewis acid is used, and a solvent-free or methanol or the like is used. It is preferable to carry out in a solvent.

  The addition reaction to the unsaturated bond of acrylic acid or methacrylic acid is preferably carried out using an excess of acrylic acid or methacrylic acid in the absence of a solvent or in a solvent such as toluene, preferably using an acid catalyst. The acid catalyst used in this addition reaction is not particularly limited, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid, p-toluenesulfonic acid, acetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid and the like. Among them, sulfuric acid, p-toluenesulfonic acid, and trifluoromethanesulfonic acid are preferable, and trifluoromethanesulfonic acid is more preferable from the viewpoint of reaction rate.

  The product of the above reaction may contain several structural isomers, geometric isomers, and optical isomers. In the present invention, a mixture of two or more isomers may be used or purified. Any of the isomers may be used alone. In the present invention, the mixture of isomers can be used in the polymerization reaction as it is. Even if a reaction intermediate is contained, it can be used in the polymerization reaction as it is. The product of the above reaction may be purified by simple distillation, thin film distillation, recrystallization, column chromatography or the like, if necessary.

2. Polymer for resist of the present invention The structural unit having a cyano group-containing alicyclic structure is preferably derived from monomers represented by the following formulas (7-1) to (7-6).

  The polymer of the present invention essentially comprises at least one structural unit selected from the group consisting of structural units represented by the above formulas (1b), (1c), and (1d).

The structural unit represented by the formula (1b) is obtained by polymerizing a monomer unit represented by the following formula (1b-m).

(In formula (1b-m), R ⁰³ , R ⁰⁴ and R ⁰⁵ have the same ^{meanings as} in formula (1b).)
Among these, a monomer unit represented by the following formula is more preferable.

(Wherein R ⁰⁸ represents a hydrogen atom or a methyl group, and m represents 1 or 2).
Specific examples of these monomer units include those represented by the following formulas (8-1) to (8-14).

The structural unit represented by the formula (1c) is derived from a monomer represented by the following formula (1c-m).

(In the formula (1c-m), R ⁰⁶ and m1 have the same meanings as in the formula (1c).)
In the formula (1c-m), R ⁰⁶ is preferably a hydrogen atom from the viewpoint of high acid detachability.

Specific examples of these monomer units include those represented by the following formulas (1c-m-1) and (1c-m-2). R is a hydrogen atom or a methyl group.

(In the formula (1d-m), R ⁰⁷ and m2 have the same meaning as in the formula (1d).)
In the formula (1d-m), R ⁰⁷ is preferably a hydrogen atom in terms of high acid detachability.

Specific examples of these monomer units include those represented by the following formulas (1d-m-1) and (1d-m-2).

In the resist polymer of the present invention, the structural unit needs to contain an acid leaving group. Here, the “acid-leaving group” refers to a group that decomposes or leaves by the action of an acid. The acid leaving group may be contained in the structural unit having the cyano group-containing alicyclic structure, and may be represented by the following formula (10-1), (10-2), or (10-3). It may be contained by copolymerizing the monomer represented. The structural unit represented by the formula (1b) has an acid leaving group, but the structural units represented by the formulas (1c) and (1d) have no acid leaving group. Other structural units having a leaving group are required.
(In Formula (10-1), R ¹⁰ represents a hydrogen atom or a methyl group, R ¹¹ represents an alkyl group having 1 to 3 carbon atoms, and X ¹ represents a hydroxy group, a carboxy group, or a carbon number 1 as a substituent. Carbon which may have at least one group selected from the group consisting of an acyl group having 6 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and an amino group A linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms. or an amino group, n1 also includes having a representative. Incidentally, n1 is 2 or more different groups as X ¹ in the case an integer of 0 to 4.
In formula (10-2), R ¹² represents a hydrogen atom or a methyl group, R ¹³ and R ¹⁴ each independently represents an alkyl group having 1 to 3 carbon atoms, and X ² represents a hydroxy group, a carboxy group as a substituent. At least one group selected from the group consisting of a group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and an amino group C1-6 linear or branched alkyl group, hydroxy group, carboxy group, C1-6 acyl group, C1-6 alkoxy group, C1-6 alcohol ester Represents a converted carboxy group or amino group, and n2 represents an integer of 0 to 4. Incidentally, also includes having a plurality of different groups as X ² in the case of n2 is 2 or more.
In Formula (10-3), R ¹⁵ represents a hydrogen atom or a methyl group, R ¹⁶ represents an alkyl group having 1 to 3 carbon atoms, and X ³ represents a hydroxy group, a carboxy group, or 1 to 3 carbon atoms as a substituent. 6 carbon atoms which may have at least one group selected from the group consisting of an acyl group having 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and an amino group A linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or Represents an amino group, n3 represents an integer of 0 to 4, and q represents 0 or 1; In addition, when n3 is 2 or more, it includes having a plurality of different groups as X ³ . In Formula (10-4), R ¹⁷ represents a hydrogen atom or a methyl group, R ¹⁸ represents an alkyl group having 1 to 3 carbon atoms, and X ⁴ represents a hydroxy group, a carboxy group, or a carbon number 1 to 1 as a substituent. 6 carbon atoms which may have at least one group selected from the group consisting of an acyl group having 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and an amino group A linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or Represents an amino group, and n4 represents an integer of 0 to 4. Incidentally, also includes having a plurality of different groups as X ⁴ in the case of n4 is 2 or more.
In formula (10-5), R ¹⁹ represents a hydrogen atom or a methyl group, R ²⁰ represents an alkyl group having 1 to 3 carbon atoms, and X ⁵ represents a hydroxy group, a carboxy group, or a carbon number 1 to 1 as a substituent. 6 carbon atoms which may have at least one group selected from the group consisting of an acyl group having 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and an amino group A linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or Represents an amino group, and n5 represents an integer of 0 to 4. Incidentally, also includes having a plurality of different groups as X ⁵ in the case of n5 is 2 or more.

In the formulas (10-1) to (10-5), the position substituted with X ^{1 to} X ⁵ may be any position in the cyclic structure.

  In this polymer, the structural units represented by the formulas (10-1) to (10-5) do not have to be all the same, and two or more types may be mixed.

Specific examples of the monomer that is polymerized and becomes a structural unit having an acid leaving group are shown in the following formulas (9-1) to (9-27). In the formula, R represents a hydrogen atom or a methyl group.

The structural unit having an acid leaving group is preferably a structural unit having an alicyclic skeleton from the viewpoint of high dry etching resistance required for a resist. The structural unit having an alicyclic skeleton is a structural unit having a structure having one or more cyclic hydrocarbon groups. Such a structural unit is usually a group in which a cyclic hydrocarbon group is eliminated by the action of an acid.

Monomers having an acid leaving group can be used alone or in combination of two or more as required.

  Among the monomers having an acid leaving group, in particular, from the viewpoint of sensitivity and resolution, the monomer represented by the above formula (9-1) and the single monomer represented by the above formula (9-2) Body, monomer represented by the above formula (9-5), monomer represented by the above formula (9-16), monomer represented by the above formula (9-23), or geometric isomerism thereof. And the optical isomers thereof are more preferable, and the monomer represented by the above formula (9-1) and the monomer represented by the above formula (9-2) are particularly preferable. The monomer represented by the above formula (9-23) is not a structural unit having an alicyclic skeleton, but is preferable from the viewpoint of obtaining high sensitivity and resolution.

  Moreover, the monomer represented by the said Formula (9-24), (9-25) (9-26), (9-27) is preferable from the point which is excellent in the solubility to a resist solvent.

  The ratio of the structural units having a cyano group-containing alicyclic structure in the resist polymer of the present invention is preferably 5 mol% or more in total, more preferably 10 mol% or more, from the viewpoint of the resist pattern shape. In addition, the ratio of the structural units having a cyano group-containing alicyclic structure in the resist polymer of the present invention is preferably 40 mol% or less, more preferably 30 mol% or less, in terms of sensitivity and resolution. .

  The ratio of the structural units represented by the formulas (1b), (1c), and (1d) in the resist polymer of the present invention is 30 in total from the viewpoint of adhesion to a metal surface or the like. It is preferably at least mol%, more preferably at least 35 mol%. Further, the ratio of the structural units having an acid leaving group in the resist polymer of the present invention is preferably 60 mol% or less, more preferably 50 mol% or less in total from the viewpoint of sensitivity and resolution.

  The resist polymer of the present invention may contain a structural unit having a lactone skeleton that can impart adhesion to the substrate.

  The structural unit having a lactone skeleton will be described.

When the structural unit having a lactone skeleton has a protecting group that is eliminated by an acid, it has better sensitivity. In addition, when the structural unit having a lactone skeleton has a high carbon density, that is, when the ratio of the number of carbon atoms to the total number of atoms in the structural unit is high, it has better dry etching resistance. R represents a hydrogen atom or a methyl group.

  Among the monomers having a lactone skeleton, from the viewpoint of sensitivity, the monomer represented by the above formula (10-1), the monomer represented by the above formula (10-2), and the above formula ( The monomer represented by 10-41) and optical isomers thereof are more preferable. From the viewpoint of dry etching resistance, the monomer represented by the above formula (10-6), and the above formula (10-10) ), A monomer represented by the above formula (10-14), a monomer represented by the above formula (10-18), and the above formula (10-21). Monomers, and geometric isomers and optical isomers thereof are more preferable. From the viewpoint of solubility in a resist solvent, the monomer represented by the above formula (10-7), the above formula (10-11), ), A monomer represented by the above formula (10-15), a monomer represented by the above formula (10-19), and These geometric isomers, optical isomers are more preferred.

Furthermore, monomers represented by the following formulas (10-51) to (10-60) are also exemplified as monomers having a lactone skeleton.

  Among these, from the viewpoint of high solubility in an organic solvent, the monomer represented by the above formula (10-55), the monomer represented by the above formula (10-56), the above formula (10− The monomer represented by 57) and the monomer represented by the above formula (10-58) are preferable, and the monomer represented by the above formula (10-58) is more preferable.

  The resist polymer of the present invention may further contain structural units other than those described above. That is, the resist polymer of the present invention includes a cyano group-containing (meth) acrylic acid ester derivative represented by the above formula (5), a monomer having an acid leaving group, and a monomer having a lactone skeleton. Other copolymerizable monomers may be copolymerized.

  The resist polymer of the present invention can contain, for example, a structural unit having an alicyclic skeleton that does not have an acid leaving group. The structural unit may be one type or two or more types.

The resist polymer containing the structural unit is excellent in dry etching resistance. Furthermore, when these structural units have a hydroxyl group, a more excellent resist pattern shape can be obtained. Specifically, the structural unit derived from the monomer shown below is mentioned.

Preferred combinations of structural units of the resist polymer of the present invention are listed below. In the formula, R represents a hydrogen atom or a methyl group.

Especially, since there are few microgels and defects, the composition containing the structural unit represented by said Formula (2) and (12-1) is preferable.

(In formula (12-1), R represents a hydrogen atom or a methyl group.)
Moreover, since a sensitivity and resolution are favorable, the composition containing the structural unit represented by following formula (12-2) and (12-3) is preferable.

(In formulas (12-2) to (12-3), R each independently represents a hydrogen atom or a methyl group.)
The mass average molecular weight of the resist polymer of the present invention is not particularly limited, but is preferably 1,000 or more, more preferably 2,000 or more, from the viewpoint of dry etching resistance and resist shape, It is especially preferable that it is 000 or more. Further, the mass average molecular weight of the resist polymer of the present invention is preferably 100,000 or less, more preferably 50,000 or less, and more preferably 30,000, from the viewpoints of solubility in a resist solution and resolution. It is particularly preferred that

3. Production Method of Resist Polymer of the Present Invention The resist polymer of the present invention is usually obtained by copolymerizing a monomer composition in the presence of a polymerization initiator. A (meth) acrylic acid ester represented by the above formula (5) is preferably polymerized by radical polymerization because it can be produced at low cost.

  In radical polymerization, first, a polymerization initiator is decomposed by heat or the like to generate a radical, and monomer chain polymerization proceeds from this radical as a starting point.

As the polymerization initiator used in the production of the resist polymer of the present invention, those that generate radicals efficiently by heat are preferable. Examples of such a polymerization initiator include 2,2′-azobisisobutyronitrile, dimethyl-2,2′-azobisisobutyrate, 2,2′-azobis [2- (2-imidazoline- Azo compounds such as 2-yl) propane; and organic peroxides such as 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane. In addition, when producing a resist polymer used in ArF excimer laser (wavelength: 193 nm) lithography, the light transmittance of the resulting resist polymer (transmittance for light with a wavelength of 193 nm) is not reduced as much as possible. As the polymerization initiator to be used, those having no aromatic ring in the molecular structure are preferable. Furthermore, in consideration of safety during polymerization, the polymerization initiator used preferably has a 10-hour half-life temperature of 60 ° C. or higher.

  In producing the resist polymer of the present invention, a chain transfer agent may be used. By using a chain transfer agent, when a low molecular weight polymer is produced, the amount of the polymerization initiator used can be reduced, and the molecular weight distribution of the resulting polymer can be reduced. The narrow molecular weight distribution is due to less high molecular weight polymer formation, which further improves solubility in resist solvents when used in resists, and the generation of microgels and defects. Is preferable because of a decrease.

  Suitable chain transfer agents include, for example, 1-butanethiol, 2-butanethiol, 1-octanethiol, 1-decanethiol, 1-tetradecanethiol, cyclohexanethiol, 2-methyl-1-propanethiol, 2-mercapto Examples include ethanol and 1-thioglycerol.

In the polymerization reaction, a polymer having a radical at the growth end is generated. However, when a chain transfer agent is used, the radical at the growth end pulls out hydrogen of the chain transfer agent, and the growth end becomes a deactivated polymer. On the other hand, the chain transfer agent from which hydrogen has been extracted becomes a structure having a radical, that is, a radical body, and the monomer is chain-polymerized again starting from this radical body. Therefore, a chain transfer residue exists at the terminal of the obtained polymer. When producing a resist polymer used in ArF excimer laser (wavelength: 193 nm) lithography, the chain used is that the light transmittance (transmittance with respect to light having a wavelength of 193 nm) of the resulting resist polymer is not lowered as much as possible. As the transfer agent, those having no aromatic ring are preferable.

  The amount of the polymerization initiator used is not particularly limited, but is preferably 0.3 mol% or more based on the total amount of monomers used for the copolymerization from the viewpoint of increasing the yield of the copolymer. From the viewpoint of narrowing the molecular weight distribution, it is preferably 30 mol% or less based on the total amount of monomers used for copolymerization. Furthermore, the amount of the polymerization initiator used is more preferably 0.1 mol% or more, particularly preferably 1 mol% or more, based on the total amount of monomers used for copolymerization.

  The amount of chain transfer agent used is not particularly limited, but it is preferably 0 mol% or more based on the total amount of monomers used for copolymerization from the viewpoint of narrowing the molecular weight distribution of the copolymer. From the viewpoint of not deteriorating resist performance such as sensitivity and resolution when used as a product, adhesion to a metal surface, etc., it is preferably 30 mol% or less based on the total amount of monomers used for copolymerization. The amount of the chain transfer agent used in the production of the resist polymer of the present invention is more preferably 5 mol% or less, particularly preferably 2 mol% or less, based on the total amount of monomers used for copolymerization.

  The method for producing the polymer of the present invention is not particularly limited, but a polymerization method called drop polymerization, which is generally performed by solution polymerization and a monomer is dropped into a polymerization vessel, is preferable. Among them, from the viewpoint that a polymer having a narrow composition distribution and / or molecular weight distribution can be easily obtained, a monomer that becomes a constituent unit of a target polymer by polymerization (even if only a monomer is used, The polymer of the present invention is preferably produced by a polymerization method called dropping polymerization in which the polymerization is carried out while dropping the solution in an organic solvent.

Although the polymerization temperature in the dropping polymerization method is not particularly limited, it is usually preferably in the range of 50 to 150 ° C.

  As the organic solvent used in the dropping polymerization method, a monomer, a polymerization initiator, a polymer to be obtained, and a solvent capable of dissolving any of the chain transfer agent when a chain transfer agent is used are preferable. Examples of such an organic solvent include 1,4-dioxane, isopropyl alcohol, acetone, tetrahydrofuran (hereinafter also referred to as “THF”), methyl ethyl ketone (hereinafter also referred to as “MEK”), methyl isobutyl ketone (hereinafter referred to as “MIBK”). And γ-butyrolactone, propylene glycol monomethyl ether acetate (hereinafter also referred to as “PGMEA”), ethyl lactate, and the like.

  The monomer concentration of the monomer solution dropped into the organic solvent is not particularly limited, but is preferably in the range of 5 to 50% by mass.

  The amount of the organic solvent charged into the polymerization vessel is not particularly limited and may be determined as appropriate. Usually, it uses within the range of 30-700 mass% with respect to the monomer whole quantity used for copolymerization.

  The polymer solution produced by a method such as solution polymerization can be prepared with a good solvent viscosity such as 1,4-dioxane, acetone, THF, MEK, MIBK, γ-butyrolactone, PGMEA, and ethyl lactate as necessary. Then, it is dropped into a large amount of poor solvent such as methanol or water to precipitate the polymer. This process is generally called reprecipitation and is very effective for removing unreacted monomers, polymerization initiators, and the like remaining in the polymerization solution. If these unreacted substances remain as they are, there is a possibility of adversely affecting the resist performance. Therefore, it is preferable to remove them as much as possible. The reprecipitation process may be unnecessary depending on circumstances. Thereafter, the precipitate is filtered off and sufficiently dried to obtain the polymer of the present invention. Moreover, after filtering off, it can also be used with a wet powder, without drying.

  Further, the produced copolymer solution can be used as a resist composition as it is or after being diluted with an appropriate solvent. At that time, additives such as a storage stabilizer may be appropriately added.

4). Resist Composition of the Present Invention The resist composition of the present invention is obtained by dissolving the resist polymer of the present invention as described above in a solvent. The chemically amplified resist composition of the present invention is obtained by dissolving the resist polymer of the present invention and a photoacid generator as described above in a solvent. The resist polymer of the present invention may be used alone or in combination of two or more. In addition, without separating the polymer from the polymer solution obtained by solution polymerization or the like, this polymer solution can be used as it is in the resist composition, or the polymer solution can be diluted with an appropriate solvent to form a resist. It can also be used in a composition.

  In the resist composition of the present invention, the solvent for dissolving the resist polymer of the present invention is arbitrarily selected according to the purpose, but the selection of the solvent is for reasons other than the solubility of the resin, for example, the uniformity of the coating film. In addition, there may be restrictions from the appearance or safety.

Examples of the solvent include linear or branched ketones such as methyl ethyl ketone, methyl isobutyl ketone and 2-pentanone; cyclic ketones such as cyclopentanone and cyclohexanone; propylene glycol monoalkyl acetates such as propylene glycol monomethyl ether acetate Ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether; ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether; diethylene glycol alkyl ethers such as diethylene glycol dimethyl ether; Esters such as ethyl acetate and ethyl lactate; n-propyl acetate Call, isopropyl alcohol, n- butyl alcohol, tert- butyl alcohol, alcohol and the like; 1,4-dioxane, ethylene carbonate, .gamma.-butyrolactone. These solvents may be used alone or in combination of two or more.

  The content of the solvent is usually 200 parts by mass or more and more preferably 300 parts by mass or more with respect to 100 parts by mass of the resist polymer (the polymer of the present invention). Further, the content of the solvent is usually 5000 parts by mass or less and more preferably 2000 parts by mass or less with respect to 100 parts by mass of the resist polymer (the polymer of the present invention).

  When the resist polymer of the present invention is used for a chemically amplified resist, it is necessary to use a photoacid generator.

  The photoacid generator contained in the chemically amplified resist composition of the present invention can be arbitrarily selected from those that can be used as the acid generator of the chemically amplified resist composition. A photo-acid generator may use 1 type or may use 2 or more types together.

  Examples of such photoacid generators include onium salt compounds, sulfonimide compounds, sulfone compounds, sulfonic acid ester compounds, quinonediazide compounds, diazomethane compounds, and the like. As the photoacid generator, among them, onium salt compounds such as sulfonium salts, iodonium salts, phosphonium salts, diazonium salts, pyridinium salts are preferable, specifically, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, Triphenylsulfonium naphthalenesulfonate, (hydroxyphenyl) benzylmethylsulfonium toluenesulfonate, diphenyliodonium triflate, diphenyliodonium pyrenesulfonate, diphenyliodonium dodecylbenzenesulfonate, diphenyliodonium hexafluoroantimonate, p-methylphenyldiphenylsulfonium nonafluorobutanesulfonate, Tri (tert-butylphenyl) sulfonium trifluor B methanesulfonate, and the like.

The content of the photoacid generator is appropriately determined depending on the type of the photoacid generator selected, but is usually 0.1 parts by mass or more with respect to 100 parts by mass of the resist polymer (the polymer of the present invention). Yes, and more preferably 0.5 parts by mass or more. By setting the content of the photoacid generator within this range, a chemical reaction due to the catalytic action of the acid generated by exposure can be sufficiently caused. Moreover, content of a photo-acid generator is 20 mass parts or less normally with respect to 100 mass parts of polymers for resists (polymer of this invention), and it is more preferable that it is 10 mass parts or less. By setting the content of the photoacid generator within this range, the stability of the resist composition is improved, and the occurrence of uneven coating during application of the composition and scum during development is sufficiently reduced.

  Furthermore, a nitrogen-containing compound can also be mix | blended with the chemically amplified resist composition of this invention. By containing a nitrogen-containing compound, the resist pattern shape, the stability over time, and the like are further improved. That is, the cross-sectional shape of the resist pattern becomes closer to a rectangle, and the resist film is exposed, heated after exposure (PEB), and left for several hours before the next development process. However, the deterioration of the cross-sectional shape of the resist pattern is further suppressed when such leaving (aging) is performed.

  As the nitrogen-containing compound, any known compounds can be used, but amines are preferable, and among them, secondary lower aliphatic amines and tertiary lower aliphatic amines are more preferable.

  Here, the “lower aliphatic amine” refers to an alkyl or alkyl alcohol amine having 5 or less carbon atoms.

  Examples of the secondary lower aliphatic amine and tertiary lower aliphatic amine include trimethylamine, diethylamine, triethylamine, di-n-propylamine, tri-n-propylamine, tripentylamine, diethanolamine, triethanolamine and the like. Is mentioned. Among these nitrogen-containing compounds, tertiary alkanolamines such as triethanolamine are more preferable.

  The nitrogen-containing compound may be used alone or in combination of two or more. The content of the nitrogen-containing compound is appropriately determined depending on the type of the selected nitrogen-containing compound, but is usually 0.01 parts by mass or more with respect to 100 parts by mass of the resist polymer (the polymer of the present invention). It is preferable. By setting the content of the nitrogen-containing compound within this range, the resist pattern shape can be made more rectangular. Moreover, it is preferable that content of a nitrogen-containing compound is 2 mass parts or less normally with respect to 100 mass parts of polymers for resists (polymer of this invention). By setting the content of the nitrogen-containing compound within this range, it is possible to reduce the sensitivity deterioration.

  In addition, the chemically amplified resist composition of the present invention may contain an organic carboxylic acid, a phosphorus oxo acid, or a derivative thereof. By containing these compounds, it is possible to prevent sensitivity deterioration due to the compounding of the nitrogen-containing compound, and further improve the resist pattern shape, the stability with time of standing, and the like.

  As the organic carboxylic acid, for example, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are preferable.

  Phosphorus oxoacids or derivatives thereof include, for example, phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenyl ester and other phosphoric acid and derivatives thereof; phosphonic acid, phosphonic acid dimethyl ester Phosphonic acids such as phosphonic acid di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, phosphonic acid dibenzyl ester, etc. and derivatives thereof; phosphinic acids such as phosphinic acid, phenylphosphinic acid and their Examples thereof include derivatives such as esters, and among them, phosphonic acid is preferable.

  These compounds (organic carboxylic acid, phosphorus oxo acid, or derivatives thereof) may be used alone or in combination of two or more.

  The content of these compounds (organic carboxylic acid, phosphorus oxo acid, or derivative thereof) is appropriately determined depending on the type of the selected compound and the like, but is usually a resist polymer (the polymer of the present invention) 100. It is preferable that it is 0.01 mass part or more with respect to a mass part. By setting the content of these compounds within this range, the resist pattern shape can be made more rectangular. In addition, the content of these compounds (organic carboxylic acid, phosphorus oxo acid or derivative thereof) is usually 5 parts by mass or less with respect to 100 parts by mass of the resist polymer (the polymer of the present invention). It is preferable. By reducing the content of these compounds within this range, the film loss of the resist pattern can be reduced.

  Note that both the nitrogen-containing compound and the organic carboxylic acid, phosphorus oxoacid, or a derivative thereof can be contained in the chemically amplified resist composition of the present invention, or only one of them can be contained. .

  Furthermore, the resist composition of the present invention may contain various additives such as surfactants, other quenchers, sensitizers, antihalation agents, storage stabilizers, and antifoaming agents as necessary. it can. Any of these additives can be used as long as it is known in the art. Moreover, the compounding quantity of these additives is not specifically limited, What is necessary is just to determine suitably.

  The resist copolymer of the present invention may be used as a resist composition for metal etching, photofabrication, plate making, hologram, color filter, retardation film and the like.

5). The method of producing a pattern present invention will now be described an example of a method for producing a pattern of the present invention.

  First, the resist composition of the present invention is applied to the surface of a substrate to be processed such as a silicon wafer on which a pattern is formed by spin coating or the like. And the to-be-processed board | substrate with which this resist composition was apply | coated is dried by baking process (prebaking) etc., and a resist film is formed on a board | substrate.

Next, the resist film thus obtained is irradiated with light having a wavelength of 250 nm or less through a photomask (exposure). The light used for exposure is preferably a KrF excimer laser, an ArF excimer laser, or an F ₂ excimer laser, and particularly preferably an ArF excimer laser. It is also preferable to expose with an electron beam.

  After exposure, heat treatment is appropriately performed (post-exposure baking, PEB), the substrate is immersed in an alkaline developer, and the exposed portion is dissolved and removed in the developer (development). Any known alkaline developer may be used. Then, after development, the substrate is appropriately rinsed with pure water or the like. In this way, a resist pattern is formed on the substrate to be processed.

  Usually, a substrate to be processed on which a resist pattern is formed is appropriately heat-treated (post-baked) to strengthen the resist, and a portion without the resist is selectively etched. After etching, the resist is usually removed using a release agent.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. In addition, “part” in each example and comparative example means “part by mass” unless otherwise specified.

  Moreover, the physical property etc. of the polymer manufactured as follows were measured.

<Mass average molecular weight of resist polymer>
About 20 mg of the resist polymer is dissolved in 5 mL of THF, and filtered through a 0.5 μm membrane filter to prepare a sample solution. This sample solution is measured using gel permeation chromatography (GPC) manufactured by Tosoh. did. For this measurement, a separation column was manufactured by Showa Denko Co., Ltd., Shodex GPC K-805L (trade name) in series, the solvent was THF, the flow rate was 1.0 mL / min, the detector was a differential refractometer, measurement Measurements were made using polystyrene as the standard polymer at a temperature of 40 ° C. and an injection volume of 0.1 mL.

<Average copolymer composition ratio of resist polymer (mol%)>
^It calculated | required by the measurement of < ¹ > H-NMR. This measurement is performed using JSX Corporation GSX-400 type FT-NMR (trade name), deuterated chloroform, deuterated acetone or deuterated about 5 mass% resist polymer sample. The dimethyl sulfoxide solution was put in a test tube having a diameter of 5 mmφ, and the measurement was carried out 64 times in a single pulse mode at a measurement temperature of 40 ° C., an observation frequency of 400 MHz.

  Moreover, using the produced polymer, a resist composition was prepared as follows, and its physical properties and the like were measured.

<Preparation of resist composition>
100 parts of the produced resist polymer, 2 parts of triphenylsulfonium triflate as a photoacid generator, and 700 parts of PGMEA as a solvent are mixed to obtain a uniform solution, and then filtered through a membrane filter having a pore size of 0.1 μm. Then, a resist composition solution was prepared.

<Formation of resist pattern>
The prepared resist composition solution was spin coated on a silicon wafer (diameter: 200 mm), and prebaked at 120 ° C. for 60 seconds using a hot plate to form a resist film having a thickness of 0.4 μm. Next, after exposure using an ArF excimer laser exposure machine (wavelength: 193 nm), post-exposure baking was performed using a hot plate at 120 ° C. for 60 seconds. Subsequently, development was performed at room temperature using a 2.38 mass% tetramethylammonium hydroxide aqueous solution, washed with pure water, and dried to form a resist pattern.

<Sensitivity>
The exposure amount (mJ / cm ² ) at which a 0.16 μm line-and-space pattern mask was transferred to a line width of 0.16 μm was measured as sensitivity.

<Resolution>
The minimum dimension (μm) of the resist pattern resolved when exposed at the exposure amount was defined as the resolution.

<Defect amount>
With respect to the resist pattern obtained as described above, the number of development defects was measured with a surface defect observation apparatus KLA2132 manufactured by KLA Tencor.

<Amount of microgel>
For the prepared resist composition solution, the number of microgels in the solution immediately after preparation (initial value of microgel) and the number of microgels in the solution after standing at 4 ° C. for 1 week (the number of microgels after aging) The number was measured with a particle counter made by Rion. Then, together with the initial value of the microgel, the increase in the number of microgels calculated by (number of microgels after time) − (initial value of microgel) was evaluated.

  Here, the number of microgels having a particle diameter of 0.25 μm or more present in 1 mL of the resist composition solution was measured.

<Example 1>
In a flask equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer, 168.9 parts of propylene glycol monomethyl ether acetate (hereinafter referred to as PGMEA) is placed under a nitrogen atmosphere, and the temperature of the hot water bath is adjusted to 80 with stirring. Raised to ° C. 2- or 3-cyano-5-norbornyl methacrylate (hereinafter referred to as CNNMA) 41.0 parts, 2-tetrahydrofurfuryl methacrylate (hereinafter referred to as THFMA) 68.0 parts, 2-methacryloyloxy- A single amount of 93.7 parts of 2-methyladamantane (hereinafter referred to as MAdMA), 304.1 parts of PGMEA and 16.4 parts of 2,2′-azobisisobutyronitrile (hereinafter referred to as AIBN). The body solution was dropped into the flask over 6 hours at a constant rate using a dropping device, and then held at 80 ° C. for 1 hour. Subsequently, the obtained reaction solution was added dropwise to about 30 times amount of methanol with stirring to obtain a white precipitate (copolymer A-1). In order to remove the monomer remaining in the precipitate, the obtained precipitate was separated by filtration, and the precipitate was washed in about 30 times as much methanol as the monomer used for the polymerization. The precipitate was filtered off and dried at 50 ° C. under reduced pressure for about 40 hours. Table 1 shows the results of measurement of physical properties of the obtained copolymer A-1.

<Example 2>
In a device similar to Example 1, 138.2 parts of PGMEA was placed under a nitrogen atmosphere, and the temperature of the hot water bath was raised to 80 ° C. while stirring. Hereinafter, a monomer solution in which 41.0 parts of CNNNMA, 68.0 parts of THFMA, 56.8 parts of t-butyl methacrylate (hereinafter referred to as TBMA), 248.8 parts of PGMEA, and 16.4 parts of AIBN are added dropwise is added. Using the apparatus, it was dropped into the flask over 6 hours at a constant speed, and then kept at 80 ° C. for 1 hour. Next, the obtained reaction solution was added dropwise to about 30 times amount of methanol with stirring to obtain a white precipitate (copolymer A-2). Thereafter, the same operations as in Example 1 were carried out, so as to obtain a copolymer A-2. Table 1 shows the results obtained by measuring the physical properties of the obtained copolymer A-2.

<Example 3>
In a device similar to Example 1, 149.6 parts of PGMEA was placed under a nitrogen atmosphere, and the temperature of the hot water bath was raised to 80 ° C. while stirring. Hereinafter, a monomer solution in which 41.0 parts of CNNNMA, 51.0 parts of THFMA, 70.2 parts of MAdMA, 17.2 parts of methacrylic acid (hereinafter referred to as MAA), 269.3 parts of PGMEA and 16.4 parts of AIBN are mixed. Was dropped into the flask over 6 hours at a constant rate using a dropping device, and then kept at 80 ° C. for 1 hour. Next, the obtained reaction solution was added dropwise to about 30 times amount of methanol with stirring to obtain a white precipitate (copolymer A-3). Thereafter, the same operations as in Example 1 were carried out, so as to obtain a copolymer A-3. Table 1 shows the results obtained by measuring the physical properties of the obtained copolymer A-3.

<Comparative Example 1>
In a device similar to Example 1, 127.1 parts of PGMEA was placed under a nitrogen atmosphere, and the temperature of the hot water bath was raised to 80 ° C. while stirring. Hereinafter, 41.0 parts of CNNNMA, 51.6 parts of 2′-acetoxyethyl methacrylate (hereinafter referred to as AEMA), 42.6 parts of TBMA, 17.2 parts of MAA, 228.7 parts of PGMEA, and 16.4 parts of AIBN were mixed. The monomer solution was dropped into the flask over 6 hours at a constant rate using a dropping device, and then held at 80 ° C. for 1 hour. Next, the obtained reaction solution was added dropwise to about 30 times amount of methanol with stirring to obtain a white precipitate (copolymer B-1). Thereafter, the same operations as in Example 1 were carried out, so as to obtain a copolymer B-1.

Table 1 shows the results of measuring the physical properties of the obtained copolymer B-1.

  Resist compositions (Examples 1 to 3) using the resist polymer of the present invention had sufficient sensitivity and resolution, and produced fewer defects and microgels in the resist solution. Line edge roughness was also good.

On the other hand, the resist composition using the polymer of Comparative Example 1 that does not contain an ether-containing structural unit was confirmed to have many defects and microgel formation in the resist solution. Line edge roughness was also great.

Claims (3)

A constitutional unit having a cyano group-containing alicyclic structure represented by the following formula (2), the following formula (1b '), at least selected from the group consisting of structural units represented by (1c), and (1d) And a proportion of the structural unit having the cyano group-containing alicyclic structure is 5 mol% or more and 40 mol% or less with respect to the total monomers, and the formula (1b ′) The ratio of at least one structural unit selected from the group consisting of the structural units represented by (1c) and (1d) is 30 mol% or more and 60 mol% or less with respect to the total of all monomers, and the mass Resist polymer having an average molecular weight of 1,000 or more and 100,000 or less.
(In the formula (2), R ⁰¹ represents a hydrogen atom or a methyl group. )
(Wherein R ⁰⁸ represents a hydrogen atom or a methyl group, and m represents 1 or 2).
(In the formula (1c), R ⁰⁶ represents a hydrogen atom or a methyl group. M1 is an integer of 0 to 3.)
(In the formula (1d), R ⁰⁷ represents a hydrogen atom or a methyl group. M2 is an integer of 0 to 3.)
  A resist composition comprising the resist polymer according to claim 1.   The process of apply | coating the composition containing the resist composition of Claim 2 and a photo-acid generator on a to-be-processed substrate, the process of exposing with the light of a wavelength of 250 nm or less, and the process of developing using a developing solution A pattern manufacturing method comprising: