JP2006063239A - Macromolecular compound, resin composition for photoresist and method for producing semiconductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a macromolecular compound for photoresists capable of forming highly water-resistant resist film. <P>SOLUTION: The macromolecular compound is composed of monomer units each represented by formula (I) (wherein, R<SP>a</SP>is H, a halogen atom, 1-6C alkyl or 1-6C haloalkyl; A is a 1-20C straight-chain or branched-chain alkylene group; the carboxy group in the formula may be in a salt form) and monomer units each having such a group as to be alkaline soluble by eliminating part thereof by the action of an acid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polymer compound for photoresist used when performing microfabrication of a semiconductor, a resin composition for photoresist containing the polymer compound, and production of a semiconductor using the resin composition for photoresist Regarding the method.

  Resin for photoresist used in the semiconductor manufacturing process has properties such as the property that the irradiated part changes to alkali-soluble when irradiated with light, adhesion to a silicon wafer (substrate), plasma etching resistance, and transparency to the light used. Must-have. The photoresist resin is generally used as a solution containing a main polymer, a photo-oxidant, and several additives for adjusting the above characteristics.

  In order to make a pattern finer, a lithography exposure light source used for manufacturing a semiconductor has become a shorter wavelength year by year. However, since there is a limit to the types of glass materials that transmit light of short wavelengths, the working distance between a substrate such as a wafer and the lens surface closest to the substrate is filled with a liquid that transmits exposure light, There has been proposed an immersion type exposure apparatus that makes an exposure pattern finer by increasing the numerical aperture (for example, Patent Document 1). Such a method of performing exposure under liquid immersion is called a wet exposure method. However, if the exposure is performed under immersion, the resist film may swell or have uneven thickness because water penetrates into the resist film when a conventional photoresist resin composition is used. There is a problem that it is difficult to obtain a clear and highly accurate pattern.

JP-A-10-303114

Accordingly, an object of the present invention is to provide a photoresist polymer compound and a photoresist resin composition capable of forming a resist film having excellent water resistance.
Another object of the present invention is to provide a polymer compound for photoresist and a resin composition for photoresist that are useful for the wet exposure method.
Still another object of the present invention is to provide a photoresist resin composition capable of forming a fine pattern clearly and accurately, and a method for producing a semiconductor.

  As a result of intensive studies to achieve the above object, the present inventors have found that a monomer unit having a specific structure having a carboxyl group in the molecule, and a monomer unit having a group that is partly eliminated by acid and becomes alkali-soluble. It has been found that the use of a polymer compound having a photoresin as a resin for a photoresist makes it possible to form a resist film having excellent water resistance, and therefore, it is useful for a wet exposure method, thereby completing the present invention.

（式中、Ｒ^aは水素原子、ハロゲン原子、炭素数１〜６のアルキル基又は炭素数１〜６のハロアルキル基を示す。Ａは炭素数１〜２０の直鎖状又は分岐鎖状のアルキレン基を示す。式中のカルボキシル基は塩に変換されていてもよい）
で表されるモノマー単位と、酸によりその一部が脱離してアルカリ可溶性となる基を有するモノマー単位とを含む高分子化合物を提供する。 That is, the present invention provides the following formula (I)

(In the formula, Ra represents ^a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. A represents a linear or branched alkylene having 1 to 20 carbon atoms. A carboxyl group in the formula may be converted to a salt)
And a monomer unit having a group that is partly eliminated by an acid and becomes alkali-soluble.

（式中、Ｒ^aは水素原子、ハロゲン原子、炭素数１〜６のアルキル基又は炭素数１〜６のハロアルキル基を示す。Ｒ¹及びＲ²は、同一又は異なって、炭素数１〜８の炭化水素基を示し、Ｒ³、Ｒ⁴及びＲ⁵は、同一又は異なって、水素原子、ヒドロキシル基又はメチル基を示す。Ｒ⁶及びＲ⁷は、同一又は異なって、水素原子、ヒドロキシル基又は−ＣＯＯＲ⁸基を示し、Ｒ⁸はｔ−ブチル基、２−テトラヒドロフラニル基、２−テトラヒドロピラニル基又は２−オキセパニル基を示す。Ｒ⁹はメチル基又はエチル基を示し、Ｒ¹⁰及びＲ¹¹は、同一又は異なって、水素原子、ヒドロキシル基又はオキソ基を示す。Ｒ¹²は、式中に示される酸素原子との結合部位に第３級炭素原子を有する、置換基を有していてもよい炭化水素基を示す。Ｒ¹³、Ｒ¹⁴、Ｒ¹⁵、Ｒ¹⁶及びＲ¹⁷は、同一又は異なって、水素原子又はメチル基を示す。Ｒ¹⁸はｔ−ブチル基、２−テトラヒドロフラニル基、２−テトラヒドロピラニル基又は２−オキセパニル基を示す。Ｒ¹⁹、Ｒ²⁰は、同一又は異なって、水素原子、アルキル基又はフルオロアルキル基を示し、Ｒ²¹は水素原子又は有機基を示す。ｍは１〜３の整数を示し、ｎは０又は１を示す）
から選択された少なくとも１種のモノマー単位が挙げられる。 As the monomer unit having a group that is partly eliminated by the acid and becomes alkali-soluble, the following formulas (IIa) to (IIh)

(In the formula, R ^a represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms or a haloalkyl group having 1 to 6 carbon atoms. R ¹ and R ² are the same or different and have 1 to 8 carbon atoms. R ³ , R ⁴ and R ⁵ are the same or different and represent a hydrogen atom, a hydroxyl group or a methyl group, and R ⁶ and R ⁷ are the same or different and represent a hydrogen atom, a hydroxyl group or shows a -COOR ⁸ group, R ⁸ is t- butyl, 2-tetrahydrofuranyl group, .R ⁹ showing a 2-tetrahydropyranyl group or a 2-oxepanyl group represents a methyl group or an ethyl group, R ¹⁰ and R ¹¹ is the same or different and represents a hydrogen atom, a hydroxyl group or an oxo group, and R ¹² has a substituent having a tertiary carbon atom at the bonding site with the oxygen atom shown in the formula. R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are the same or different and each represents a hydrogen atom or a methyl group, and R ¹⁸ represents a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or a 2-oxepanyl group. R ¹⁹ and R ²⁰ are the same or different and each represents a hydrogen atom, an alkyl group or a fluoroalkyl group, R ²¹ represents a hydrogen atom or an organic group, m represents an integer of 1 to 3, and n represents 0. Or 1)
And at least one monomer unit selected from

  The monomer unit represented by the formula (I) is preferably 1 to 20 mol% of the total monomer units.

  The present invention also provides a photoresist resin composition comprising at least the polymer compound and a photoacid generator. This resin composition can be used as a resin composition for a photoresist for immersion exposure.

  The present invention further provides a method for producing a semiconductor, comprising the steps of: applying the photoresist resin composition on a substrate or substrate to form a resist coating film; and exposing and developing to form a pattern. . The exposure may be performed under immersion.

  According to the present invention, a resist film having excellent water resistance can be formed and can be suitably used for a wet exposure method. In addition, according to the photoresist resin composition and the semiconductor manufacturing method of the present invention, a resist film having excellent water resistance can be formed. By adopting a wet exposure method, a fine pattern can be formed with high accuracy. be able to.

[Polymer compound]
The polymer compound of the present invention comprises, as a structural unit constituting a polymer molecule, a monomer unit (repeating unit) (hereinafter sometimes referred to as “monomer unit 1”) represented by the formula (I) and an acid. A monomer unit having a group that is partially eliminated and becomes alkali-soluble (hereinafter sometimes referred to as “monomer unit 2”) is included. Since the monomer unit 1 has a highly hydrophilic carboxyl group, the monomer unit 1 functions as an adhesion-imparting unit that improves adhesion to the substrate, and also has a function of improving solubility in an alkali developer. In addition, since it has a highly hydrophobic and chain-like alkylene group between the oxygen atom constituting the ester and the terminal carboxyl group, when the resist film is formed, the carboxyl group is located on the substrate side, Since the hydrophobic group is located on the surface side of the resist film, the penetration of water into the resist film is suppressed. For this reason, even if it exposes by the wet exposure method, it has the characteristic that a resist film does not swell easily with water.

  On the other hand, since the monomer unit 2 changes to alkali-soluble upon light irradiation, it functions as an alkali-soluble unit that solubilizes the resin during alkali development. Therefore, the polymer compound of the present invention is useful as a photoresist resin, particularly as a photoresist resin used when forming a pattern using a wet exposure method.

In the monomer unit represented by the formula (I), Ra represents ^a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. A represents a linear or branched alkylene group having 1 to 20 carbon atoms. The carboxyl group in formula (I) may form a salt. The monomer unit represented by the formula (I) contained in the polymer may be one type or two or more types.

The halogen atom in R ^a includes a fluorine, chlorine, bromine atom and the like. Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, and hexyl groups. Examples of the haloalkyl group having 1 to 6 carbon atoms include groups in which at least one hydrogen atom of the alkyl group having 1 to 6 carbon atoms is substituted with a fluorine atom, such as monofluoromethyl, difluoromethyl, trifluoromethyl, 2,2 , 2-trifluoroethyl, tetrafluoroethyl, 2,2,3,3,3-tetrafluoropropyl group and the like. R ^a is particularly preferably a hydrogen atom or a methyl group.

  Examples of the linear or branched alkylene group having 1 to 20 carbon atoms in A include methylene, ethylene, propylene, dimethylmethylene, 1,1-dimethylethylene, 1-ethylethylene, trimethylene, 1-methyltrimethyl. Methylene, 2-methyltrimethylene, 2,2-dimethyltrimethylene, tetramethylene, pentamethylene, hexamethylene, octamethylene, decamethylene, dodecamethylene, tetradecamethylene, pentadecamethylene, hexadecamethylene, octadecamethylene group, etc. Is mentioned. Among these, a linear or branched alkylene group having 2 to 15 carbon atoms is preferable, and a linear or branched alkylene group having 3 to 10 carbon atoms is particularly preferable.

  The salt of the carboxyl group represented by the formula (I) is not particularly limited, and examples thereof include alkali metal salts, alkaline earth metal salts, ammonium salts, salts with amines, and salts with nitrogen-containing heterocyclic compounds. Can be mentioned.

  The monomer unit having a group that is partially eliminated by an acid and becomes alkali-soluble is not particularly limited. For example, it is used as a monomer unit having an acid-eliminable group or an alkali-soluble group in a polymer compound for photoresist. Known monomer units can be employed. The polymer compound of the present invention may have one kind of these monomer units or two or more kinds.

  Monomer units preferable as monomer units having a group that is partially eliminated by an acid and becomes alkali-soluble include monomer units represented by the above formulas (IIa) to (IIh).

R ^a in formulas (IIa) to (IIh) is the same as described above. In formula (IIa), the hydrocarbon having 1 to 8 carbon atoms in R ¹ and R ² is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, pentyl, isopentyl, 1-methylbutyl, 1-ethyl. C _1-8 alkyl groups such as propyl, hexyl, isohexyl, 1-methylpentyl, 1-ethylbutyl, heptyl, 1-methylhexyl, octyl, 1-methylheptyl group; cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl A C _3-8 cycloalkyl group such as a group; and a phenyl group. Among these, C _1-3 alkyl groups such as methyl, ethyl, and isopropyl groups are preferable.

In formula (IId), examples of the “hydrocarbon group having a tertiary carbon atom at the bonding site with the oxygen atom represented by the formula” in R ¹² include a t-butyl group and a t-amyl group. It is done. These hydrocarbon groups may have a substituent.

In formula (IIh), the alkyl group for R ¹⁹ and R ²⁰ is a linear or branched alkyl group such as methyl, ethyl, propyl, isopropyl, sec-butyl, pentyl, hexyl group (C _1-6 Alkyl group, etc.). The fluoroalkyl group includes a group in which at least one hydrogen atom of the alkyl group is substituted with a fluorine atom, such as monofluoromethyl, difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl, tetrafluoro Examples include ethyl, 2,2,3,3,3-tetrafluoropropyl group. R ¹⁹ and R ²⁰ are particularly preferably a hydrogen atom, a C _1-3 alkyl group, a C _1-3 fluoroalkyl group, or the like.

In the formula (IIh), examples of the organic group for R ²¹ include a group containing a hydrocarbon group and / or a heterocyclic group.

The hydrocarbon group includes an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group in which two or more of these are bonded. Examples of the aliphatic hydrocarbon group include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, hexyl, and octyl groups (C _{1- 8} alkyl groups); linear or branched alkenyl groups such as allyl groups (C _2-8 alkenyl groups, etc.); linear or branched alkynyl groups such as propynyl groups (C _2-8 alkynyl) Group, etc.). Examples of the alicyclic hydrocarbon group include cycloalkyl groups such as cyclopropyl, cyclopentyl, and cyclohexyl groups (3 to 8 membered cycloalkyl groups); cycloalkenyl groups such as cyclopentenyl and cyclohexenyl groups (3 to 8 members). Cycloalkenyl groups and the like); bridged carbocyclic groups such as adamantyl and norbornyl groups (C _4-20 bridged carbocyclic groups and the like) and the like. Examples of the aromatic hydrocarbon group include C _6-14 aromatic hydrocarbon groups such as phenyl and naphthyl groups. Examples of the group in which an aliphatic hydrocarbon group and an aromatic hydrocarbon group are bonded include benzyl and 2-phenylethyl groups.

These hydrocarbon groups, an alkyl group (C _1-4 alkyl group), haloalkyl group (C _1-4 haloalkyl group), a halogen atom, a protected or unprotected hydroxyl group with a protecting group, protected by a protecting group It may have a substituent such as a hydroxymethyl group which may be protected, a carboxyl group which may be protected with a protecting group, or an oxo group. As the protecting group, a protecting group conventionally used in the field of organic synthesis can be used.

  Examples of the heterocyclic group include heterocyclic groups containing at least one heteroatom selected from an oxygen atom, a sulfur atom and a nitrogen atom.

Preferred organic groups include C _1-8 alkyl groups, organic groups containing a cyclic skeleton, and the like. The “ring” constituting the cyclic skeleton includes a monocyclic or polycyclic non-aromatic or aromatic carbocyclic or heterocyclic ring. Of these, monocyclic or polycyclic non-aromatic carbocycles and lactone rings (which may be condensed with non-aromatic carbocycles) are particularly preferable. Examples of the monocyclic non-aromatic carbocycle include a cycloalkane ring having about 3 to 15 members such as a cyclopentane ring and a cyclohexane ring.

Examples of the polycyclic non-aromatic carbocycle (bridged carbocycle) include, for example, an adamantane ring, norbornane ring, norbornene ring, bornane ring, isobornane ring, adamantane ring; norbornane ring, norbornene ring, bornane ring, isobornane ring, tricyclo [5.2.1.0 ^2,6 ] decane ring, tetracyclo [4.4.0.1 ^2,5 . ^1,7,10 ] ring containing norbornane ring or norbornene ring such as dodecane ring; perhydroindene ring, decalin ring (perhydronaphthalene ring), perhydrofluorene ring (tricyclo [7.4.0.0 ^3,8 ] Tridecane ring), a ring in which a polycyclic aromatic condensed ring such as perhydroanthracene ring is hydrogenated (preferably a fully hydrogenated ring); a tricyclo [4.2.2.1 ^2,5 ] undecane ring, etc. And a bridged carbocyclic ring (for example, a bridged carbocyclic ring having about 6 to 20 carbon atoms). Examples of the lactone ring include a γ-butyrolactone ring, 4-oxatricyclo [4.3.1.1 ^3,8 ] undecan-5-one ring, and 4-oxatricyclo [4.2.1.0 ^{3. , 7} ] nonan-5-one ring, 4-oxatricyclo [5.2.1.0 ^2,6 ] decan-5-one ring, and the like.

The ring constituting the cyclic skeleton includes an alkyl group such as a methyl group (eg, a C _1-4 alkyl group), a haloalkyl group such as a trifluoromethyl group (eg, a C _1-4 haloalkyl group), a chlorine atom Or a halogen atom such as a fluorine atom, a hydroxyl group that may be protected with a protective group, a hydroxyalkyl group that may be protected with a protective group, a mercapto group that may be protected with a protective group, or a protective group. It may have a substituent such as a carboxyl group which may be protected, an amino group which may be protected with a protecting group, and a sulfonic acid group which may be protected with a protecting group. As the protecting group, a protecting group conventionally used in the field of organic synthesis can be used.

The ring constituting the cyclic skeleton may be directly bonded to an oxygen atom (oxygen atom adjacent to R ²¹ ) shown in the formula (IIh) or may be bonded via a linking group. . Examples of the linking group include a linear or branched alkylene group such as methylene, methylmethylene, dimethylmethylene, ethylene, propylene, and trimethylene group; a carbonyl group; an oxygen atom (ether bond; —O—); an oxycarbonyl group ( An ester bond; —COO—); an aminocarbonyl group (amide bond; —CONH—); and a group in which a plurality of these are bonded.

  The monomer unit represented by the formula (IIa) is desorbed from the carboxylic acid moiety in which the site containing the adamantane skeleton is bonded to the main chain by an acid to generate a free carboxyl group. In the monomer unit represented by the formula (IIb), a carboxyl group protected by a protecting group bonded to an adamantane skeleton is deprotected by an acid to generate a free carboxyl group. The monomer unit represented by the formula (IIc) generates a free carboxyl group by elimination from the carboxylic acid moiety in which the adamantane skeleton is bonded to the main chain by an acid. Furthermore, in the monomer units represented by the formulas (IId), (IIe), (IIf), (IIg) and (IIh), the carboxylic acid ester moiety is decomposed and eliminated by an acid to generate a free carboxyl group.

The monomer units represented by the formulas (IIa), (IIb), (IIc) and (IIg), and the monomer units in which R ²¹ is a group containing a non-aromatic carbocycle in the formula (IIh) are fatty acids. Since it has a cyclic carbon skeleton, it has the characteristics of excellent transparency and extremely high etching resistance. In addition, in the formula (IIa), a monomer unit in which at least one of R ^{3 to} R ⁵ is a hydroxyl group, a monomer unit represented by the formula (IIf), and a group in which R ^{21 in the} formula (IIh) contains a lactone ring The monomer unit is highly hydrophilic and also has an adhesive function.

  In addition to the monomer units 1 and 2 described above, the polymer compound of the present invention may include other monomer units (repeating units) in order to have characteristics necessary as a resist resin. Examples of such monomer units include monomer units represented by the following formulas (IIIa) to (IIIh) (hereinafter sometimes referred to as “monomer unit 3”).

（式中、Ｒ^aは水素原子、ハロゲン原子、炭素数１〜６のアルキル基又は炭素数１〜６のハロアルキル基を示す。Ｒ²²及びＲ²³は、同一又は異なって、水素原子、ヒドロキシル基又はカルボキシル基を示し、Ｒ²⁴はヒドロキシル基、オキソ基又はカルボキシル基を示す。Ｘ¹、Ｘ²及びＸ³は、同一又は異なって、−ＣＨ₂−又は−ＣＯ−Ｏ−を示す。Ｒ²⁵、Ｒ²⁶及びＲ²⁷は、同一又は異なって、水素原子又はメチル基を示す。Ｒ²⁸及びＲ²⁹は、同一又は異なって、水素原子又はメチル基を示す。Ｒ³⁰、Ｒ³¹、Ｒ³²、Ｒ³³及びＲ³⁴は、同一又は異なって、水素原子又はメチル基を示す。Ｒ³⁵は、水素原子、又は置換基を有していてもよい炭素数１〜２０の直鎖状、分岐鎖状、環状若しくは有橋環状炭化水素基を示す。Ｒ³⁶、Ｒ³⁷、Ｒ³⁸及びＲ³⁹は、同一又は異なって、水素原子又はメチル基を示す。Ｒ⁴⁰は、水素原子、ヒドロキシル基、ヒドロキシメチル基又はカルボキシル基を示す。ｏ、ｐ、ｑ及びｒは、それぞれ、０又は１を示す）

(In the formula, R ^a represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms or a haloalkyl group having 1 to 6 carbon atoms. R ²² and R ²³ are the same or different and represent a hydrogen atom or a hydroxyl group. or a carboxyl group, R ²⁴ represents a hydroxyl group, .X ^1, X ² and X ³ showing an oxo group or a carboxyl group are the same or different, -CH ₂ - or .R ²⁵ showing a -CO-O- , R ²⁶ and R ²⁷ are the same or different and each represents a hydrogen atom or a methyl group, R ²⁸ and R ²⁹ are the same or different and each represents a hydrogen atom or a methyl group, R ³⁰ , R ³¹ , R ³² , R ³³ and R ³⁴ are the same or different and each represents a hydrogen atom or a methyl group, and R ³⁵ is a hydrogen atom or a linear or branched chain having 1 to 20 carbon atoms which may have a substituent. , .R ^36, R ³⁷ showing a cyclic or bridged cyclic hydrocarbon group, R ³⁸ and ³⁹ are the same or different, .R ⁴⁰ represent a hydrogen atom or a methyl group, a hydrogen atom, a hydroxyl group, .o showing a hydroxymethyl group or a carboxyl group, p, q and r are, respectively, 0 or 1 Show)

R ^a in formulas (IIIa) to (IIIh) is the same as described above. In the formula (IIIb), the direction of the —CO—O— group in X ^{1 to} X ³ is not limited. In the formula (IIIe), the linear, branched, cyclic or bridged cyclic hydrocarbon group (bridged cyclic group) having 1 to 20 carbon atoms in R ³⁵ is methyl, ethyl, propyl, isopropyl , Butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, decyl, dodecyl, tetradecyl, octadecyl and the like linear or branched aliphatic hydrocarbon groups (particularly alkyl groups) such as cyclopentyl; Cycloalkyl, cycloalkenyl group such as cyclohexyl, cyclooctyl, cyclododecyl group, etc .; perhydroindene ring, perhydrofluorene ring, perhydronaphthalene ring (decalin ring), perhydroanthracene ring, norbornane ring , Norbornene ring, pinane ring, bornane ring, isobornylane ring, tricyclo [5. 2.1.0 ^2,6 ] decane ring, tetracyclo [4.4.0.1 ^2,5 . 1 ^{7, 10} ] bridged cyclic hydrocarbon group having 6 to 20 carbon atoms (bridged cyclic hydrocarbon group) corresponding to dodecane ring, etc .; tricyclo [5.2.1.0 ^2,6 ] decylmethyl group, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] Dodecylmethyl group, 2-norbornylmethyl group and the like, and the like groups bonded to each of the hydrocarbon groups. These hydrocarbon groups include an alkyl group, a halogen atom, a hydroxyl group that may be protected with a protecting group, a hydroxymethyl group that may be protected with a protecting group, and a carboxyl group that may be protected with a protecting group ( For example, it has a substituent such as a carboxyl group, a t-butyloxycarbonyl group, a 2-tetrahydrofuranyloxycarbonyl group, a 2-tetrahydropyranyloxycarbonyl group, a 2-oxepanyloxycarbonyl group, and an oxo group. May be. As the protecting group, a protecting group commonly used in the field of organic synthesis can be used.

The monomer unit represented by the formula (IIIa) has a function of improving adhesion to a substrate because a highly hydrophilic group (hydroxyl group, carboxyl group, oxo group) is bonded to the adamantane skeleton. In addition, formulas (IIIa), (IIIb) (wherein X ^{1 to} X ³ are all methylene groups, etc.), (IIIc), (IIIe) (where R ³⁵ is a cyclic or bridged cyclic hydrocarbon group), Since the monomer units represented by (IIIg) and (IIIh) have an alicyclic carbon skeleton, they contribute to improvements in transparency and etching resistance. A monomer unit having a lactone skeleton represented by formula (IIIb) (wherein at least one of X ^{1 to} X ³ is a —CO—O— group), (IIIc), (IIId) and (IIIg), ) (In which R ³⁵ is a hydrogen atom), (IIIf), (IIIh) (in which R ⁴⁰ is a hydroxyl group, a hydroxymethyl group or a carboxyl group) the monomer unit contains a hydrophilic group , Has an adhesion imparting function. Thus, since these monomer units can give various functions based on their structures, incorporation of each of the above monomer units into the polymer makes it possible to finely balance the various properties required as a resist resin depending on the application. Can be adjusted.

  In the polymer compound of the present invention, the content of the monomer unit 1 is, for example, 1 to 20 mol%, preferably 2 to 15 mol%, more preferably 3 to 12 mol, based on the entire monomer unit constituting the polymer. %. Moreover, in a preferable high molecular compound, the monomer unit 2 is contained, for example, about 10 to 99 mol%, preferably 12 to 97 mol%, and more preferably about 15 to 96 mol% with respect to the whole monomer units constituting the polymer. . Further, the content of the monomer unit 3 in the polymer compound containing the monomer unit 3 is, for example, 10 to 80 mol%, preferably 20 to 70 mol%, more preferably 30 with respect to the entire monomer unit constituting the polymer. It is about ~ 60 mol%.

  The weight average molecular weight (Mw) of the polymer compound is, for example, about 5000 to 50000, preferably about 7000 to 20000, and the molecular weight distribution (Mw / Mn) is, for example, about 1.8 to 3.5. In addition, said Mn shows a number average molecular weight, and both Mn and Mw are values of polystyrene conversion.

  Each of the monomer units represented by the formulas (IIg), (IIIf), (IIIg) and (IIIh) has a corresponding ethylenically unsaturated compound as a (co) monomer, and the formula (I), (IIa ) To (IIf), (IIh), (IIIa) to (IIIe), each monomer unit is polymerized by using a corresponding (meth) acrylic acid or other unsaturated carboxylic acid or ester thereof as a (co) monomer. It can be formed by attaching to.

（式中、Ｒ^a、Ａは前記に同じ。式中のカルボキシル基は塩に変換されていてもよい）
で表される。式（１）で表されるモノマーは単独で又は２種以上組み合わせて使用できる。 [Monomer unit of formula (I)]
The monomer corresponding to the monomer unit of the formula (I) is represented by the following formula (1)

(In the formula, R ^a and A are the same as above. The carboxyl group in the formula may be converted to a salt)
It is represented by The monomers represented by the formula (1) can be used alone or in combination of two or more.

  Typical examples of the monomer represented by the formula (1) include the following compounds. 2- (meth) acryloyloxyacetic acid, 3- (meth) acryloyloxypropionic acid, 4- (meth) acryloyloxybutanoic acid, 5- (meth) acryloyloxypentanoic acid, 6- (meth) acryloyloxyhexanoic acid, 8 -(Meth) acryloyloxyoctanoic acid, 10- (meth) acryloyloxydecanoic acid, 12- (meth) acryloyloxide decanoic acid, 14- (meth) acryloyloxytetradecanoic acid, 16- (meth) acryloyloxyhexadecanoic acid, 18 -(Meth) acryloyloxyoctadecanoic acid and the like.

  The monomer represented by the formula (1) can be obtained by a known method, for example, a method described in JP-A-6-80624.

[Monomer unit of formula (IIa)]
As typical examples of the monomer corresponding to the monomer unit of the formula (IIa), there may be mentioned the following compounds. 1- (1- (meth) acryloyloxy-1-methylethyl) adamantane, 1-hydroxy-3- (1- (meth) acryloyloxy-1-methylethyl) adamantane, 1- (1-ethyl-1- ( (Meth) acryloyloxypropyl) adamantane, 1-hydroxy-3- (1-ethyl-1- (meth) acryloyloxypropyl) adamantane, 1- (1- (meth) acryloyloxy-1-methylpropyl) adamantane, 1- Hydroxy-3- (1- (meth) acryloyloxy-1-methylpropyl) adamantane, 1- (1- (meth) acryloyloxy-1,2-dimethylpropyl) adamantane, 1-hydroxy-3- (1- ( (Meth) acryloyloxy-1,2-dimethylpropyl) adamantane, 1,3-dihydroxy -5- (1- (meth) acryloyloxy-1-methylethyl) adamantane, 1- (1-ethyl-1- (meth) acryloyloxypropyl) -3,5-dihydroxyadamantane, 1,3-dihydroxy-5 -(1- (meth) acryloyloxy-1-methylpropyl) adamantane, 1,3-dihydroxy-5- (1- (meth) acryloyloxy-1,2-dimethylpropyl) adamantane.

[Monomer unit of formula (IIb)]
As typical examples of the monomer corresponding to the monomer unit of the formula (IIb), there may be mentioned the following compounds. 1-t-butoxycarbonyl-3- (meth) acryloyloxyadamantane, 1,3-bis (t-butoxycarbonyl) -5- (meth) acryloyloxyadamantane, 1-t-butoxycarbonyl-3-hydroxy-5 (Meth) acryloyloxyadamantane, 1- (2-tetrahydropyranyloxycarbonyl) -3- (meth) acryloyloxyadamantane, 1,3-bis (2-tetrahydropyranyloxycarbonyl) -5- (meth) acryloyloxy Adamantane, 1-hydroxy-3- (2-tetrahydropyranyloxycarbonyl) -5- (meth) acryloyloxyadamantane.

[Monomer unit of formula (IIc)]
As typical examples of the monomer corresponding to the monomer unit of the formula (IIc), there may be mentioned the following compounds. 2- (meth) acryloyloxy-2-methyladamantane, 1-hydroxy-2- (meth) acryloyloxy-2-methyladamantane, 5-hydroxy-2- (meth) acryloyloxy-2-methyladamantane, 1,3 -Dihydroxy-2- (meth) acryloyloxy-2-methyladamantane, 1,5-dihydroxy-2- (meth) acryloyloxy-2-methyladamantane, 1,3-dihydroxy-6- (meth) acryloyloxy-6 -Methyl adamantane, 2- (meth) acryloyloxy-2-ethyladamantane, 1-hydroxy-2- (meth) acryloyloxy-2-ethyladamantane, 5-hydroxy-2- (meth) acryloyloxy-2-ethyladamantane 1,3-dihydroxy-2- (meth) ac Liloyloxy-2-ethyladamantane, 1,5-dihydroxy-2- (meth) acryloyloxy-2-ethyladamantane, 1,3-dihydroxy-6- (meth) acryloyloxy-6-ethyladamantane.

[Monomer unit of formula (IId)]
As typical examples of the monomer corresponding to the monomer unit of the formula (IId), there may be mentioned the following compounds. t-Butyl (meth) acrylate.

[Monomer unit of formula (IIe)]
As typical examples of the monomer corresponding to the monomer unit of the formula (IIe), there may be mentioned the following compounds. 2-tetrahydropyranyl (meth) acrylate, 2-tetrahydrofuranyl (meth) acrylate.

[Monomer unit of formula (IIf)]
As typical examples of the monomer corresponding to the monomer unit of the formula (IIf), there may be mentioned the following compounds. β- (meth) acryloyloxy-γ-butyrolactone, β- (meth) acryloyloxy-α, α-dimethyl-γ-butyrolactone, β- (meth) acryloyloxy-γ, γ-dimethyl-γ-butyrolactone, β- (Meth) acryloyloxy-α, α, β-trimethyl-γ-butyrolactone, β- (meth) acryloyloxy-β, γ, γ-trimethyl-γ-butyrolactone, β- (meth) acryloyloxy-α, α, β, γ, γ-pentamethyl-γ-butyrolactone.

[Monomer unit of formula (IIg)]
As typical examples of the monomer corresponding to the monomer unit of the formula (IIg), there may be mentioned the following compounds. 5-t-butoxycarbonylnorbornene, 9-t-butoxycarbonyltetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodec-4-ene, 5- (2-tetrahydropyranyloxycarbonyl) norbornene, 9- (2-tetrahydropyranyloxycarbonyl) tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodec-4-ene.

[Monomer unit of formula (IIh)]
As typical examples of the monomer corresponding to the monomer unit of the formula (IIh), there may be mentioned the following compounds. 1- (adamantan-1-yloxy) ethyl (meth) acrylate, 1- (adamantan-1-ylmethoxy) ethyl (meth) acrylate, 1- [2- (adamantan-1-yl) ethoxy] ethyl (meth) acrylate, 1- (3-hydroxyadamantan-1-yloxy) ethyl (meth) acrylate, 1- (norbornan-2-yloxy) ethyl (meth) acrylate, 1- (norbornan-2-ylmethoxy) ethyl (meth) acrylate, 1- (2-methylnorbornan-2-yloxy) ethyl (meth) acrylate, 1- [1- (norbornan-2-yl) -1-methylethoxy] ethyl (meth) acrylate, 1- (3-methylnorbornane-2- Ylmethoxy) ethyl (meth) acrylate, 1- (bornyloxy) ) Ethyl (meth) acrylate, 1- (isobornyloxycarbonyl) ethyl (meth) acrylate; 1- [1- (meth) acryloyloxy ethoxy] -4-oxa-tricyclo [4.3.1.1 ^{3, 8} ] Undecan-5-one, 2- [1- (meth) acryloyloxyethoxy] -4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-5-one, 8- [1- (meta ) Acrylyloxyethoxy] -4-oxatricyclo [5.2.1.0 ^2,6 ] decan-5-one, 9- [1- (meth) acryloyloxyethoxy] -4-oxatricyclo [5. 2.1.0 ^2,6 ] decan-5-one, α- [1- (meth) acryloyloxyethoxy] -γ, γ-dimethyl-γ-butyrolactone, 3- [1- (meth) acryloyloxyethoxy] -2-oxo-1- Oxaspiro [4.5] decane, α- [1- (meth) acryloyloxyethoxy] -γ-butyrolactone, α- [1- (meth) acryloyloxyethoxy] -α, γ, γ-trimethyl-γ-butyrolactone, α- [1- (Meth) acryloyloxyethoxy] -β, β-dimethyl-γ-butyrolactone.

[Monomer unit of formula (IIIa)]
Typical compounds of the monomer corresponding to the monomer unit of the formula (IIIa) include the following compounds. 1-hydroxy-3- (meth) acryloyloxyadamantane, 1,3-dihydroxy-5- (meth) acryloyloxyadamantane, 1-carboxy-3- (meth) acryloyloxyadamantane, 1,3-dicarboxy-5 (Meth) acryloyloxyadamantane, 1-carboxy-3-hydroxy-5- (meth) acryloyloxyadamantane, 1- (meth) acryloyloxy-4-oxoadamantane, 3-hydroxy-1- (meth) acryloyloxy-4 -Oxoadamantane, 7-hydroxy-1- (meth) acryloyloxy-4-oxoadamantane.

[Monomer unit of formula (IIIb)]
As typical examples of the monomer corresponding to the monomer unit of the formula (IIIb), there may be mentioned the following compounds. 1- (meth) acryloyloxy-4-oxatricyclo [4.3.1.1 ^3,8 ] undecan-5-one, 1- (meth) acryloyloxy-4,7-dioxatricyclo [4. 4.1.1 ^3,9 ] dodecane-5,8-dione, 1- (meth) acryloyloxy-4,8-dioxatricyclo [4.4.1.1 ^3,9 ] dodecane-5,7 -Dione, 1- (meth) acryloyloxy-5,7-dioxatricyclo [4.4.1.1 ^3,9 ] dodecane-4,8-dione.

[Monomer unit of formula (IIIc)]
Typical examples of the monomer that forms the monomer unit of the formula (IIIc) include the following compounds. 2- (Meth) acryloyloxy-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-5-one, 2- (meth) acryloyloxy-2-methyl-4-oxatricyclo [4 .2.1.0 ^3,7 ] nonan-5-one.

[Monomer unit of formula (IIId)]
Typical examples of the monomer forming the monomer unit of the formula (IIId) include the following compounds. α- (meth) acryloyloxy-γ-butyrolactone, α- (meth) acryloyloxy-α-methyl-γ-butyrolactone, α- (meth) acryloyloxy-β, β-dimethyl-γ-butyrolactone, α- (meta ) Acrylyloxy-α, β, β-trimethyl-γ-butyrolactone, α- (meth) acryloyloxy-γ, γ-dimethyl-γ-butyrolactone, α- (meth) acryloyloxy-α, γ, γ-trimethyl- γ-butyrolactone, α- (meth) acryloyloxy-β, β, γ, γ-tetramethyl-γ-butyrolactone, α- (meth) acryloyloxy-α, β, β, γ, γ-pentamethyl-γ-butyrolactone .

[Monomer unit of formula (IIIe)]
Typical examples of the monomer forming the monomer unit of the formula (IIIe) include the following compounds. (Meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate, decahydro (meth) acrylate Naphthyl, norbornyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, dimethyladamantyl (meth) acrylate, tricyclo [5.2.1.0 ^2,6 ] decyl (meth) acrylate , Tetracyclo (meth) acrylate [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecyl. A compound in which a substituent such as a hydroxy group, a hydroxymethyl group, a carboxyl group, or an oxo group is bonded to a group corresponding to R ³⁷ of these compounds is also preferable.

[Monomer unit of formula (IIIf)]
The monomer forming the monomer unit of the formula (IIIf) includes maleic anhydride.

[Monomer unit of formula (IIIg)]
Typical examples of the monomer that forms the monomer unit of the formula (IIIg) include the following compounds. 4-oxatricyclo [5.2.1.0 ^2,6 ] decan-8-en-5-one, 3-oxatricyclo [5.2.1.0 ^2,6 ] decan-8-ene- 4-one, 5-oxatricyclo [6.2.1.0 ^2,7 ] undecan-9-en-6-one, 4-oxatricyclo [6.2.1.0 ^2,7 ] undecane- 9-en-5-one, 4-oxapentacyclo [6.5.1.1 ^9,12 . 0 ^2,6 . 0 ^8,13 ] pentadecan-10-en-5-one, 3-oxapentacyclo [6.5.1.1 ^9,12 . 0 ^2,6 . 0 ^8,13] pentadecane-10-en-4-one, 5-oxa penta cyclo [6.6.1.1 ^{10, 13.} 0 ^2,7 . 0 ^9,14] hexadecane-11-en-6-one, 4-oxa-penta cyclo [6.6.1.1 ^{10, 13.} 0 ^2,7 . 0 ^9,14 ] Hexadecan-11-en-5-one.

[Monomer unit of formula (IIIh)]
As typical examples of the monomer forming the monomer unit of the formula (IIIh), there may be mentioned the following compounds. Norbornene, 5-hydroxy-2-norbornene.

  In obtaining the polymer compound of the present invention, the polymerization of the monomer mixture is carried out by a conventional method used for producing an acrylic polymer, such as solution polymerization, bulk polymerization, suspension polymerization, bulk-suspension polymerization, and emulsion polymerization. Although it can be performed, solution polymerization is particularly preferred. Furthermore, drop polymerization is preferable among solution polymerization. Specifically, for example, (i) a monomer solution previously dissolved in an organic solvent and a polymerization initiator solution dissolved in an organic solvent are prepared in an organic solvent kept at a constant temperature. A method in which the monomer solution and the polymerization initiator solution are respectively dropped, and (ii) a method in which a mixed solution in which the monomer and the polymerization initiator are dissolved in an organic solvent is dropped into an organic solvent maintained at a constant temperature. (Iii) A monomer solution previously dissolved in an organic solvent and a polymerization initiator solution dissolved in the organic solvent are respectively prepared, and the polymerization initiator solution is dropped into the monomer solution maintained at a constant temperature. It is performed by a method or the like.

  As the polymerization solvent, a known solvent can be used. For example, ether (chain ether such as diethyl ether, propylene glycol monomethyl ether, etc., chain ether such as tetrahydrofuran, dioxane, etc.), ester (methyl acetate, ethyl acetate, Glycol ether esters such as butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), amides (N, N-dimethylacetamide, N, N-dimethylformamide, etc.) ), Sulfoxide (dimethylsulfoxide, etc.), alcohol (methanol, ethanol, propanol, etc.), hydrocarbon (aromatic hydrocarbons such as benzene, toluene, xylene, etc.) Aliphatic hydrocarbons such as hexane, and alicyclic hydrocarbons such as cyclohexane), and mixtures of these solvents. Moreover, a well-known polymerization initiator can be used as a polymerization initiator. The polymerization temperature can be appropriately selected within a range of about 30 to 150 ° C., for example.

  The polymer obtained by polymerization can be purified by precipitation or reprecipitation. The precipitation or reprecipitation solvent may be either an organic solvent or water, or a mixed solvent. Examples of the organic solvent used as the precipitation or reprecipitation solvent include hydrocarbons (aliphatic hydrocarbons such as pentane, hexane, heptane, and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aromatics such as benzene, toluene, and xylene. Aromatic hydrocarbons), halogenated hydrocarbons (halogenated aliphatic hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride; halogenated aromatic hydrocarbons such as chlorobenzene and dichlorobenzene), nitro compounds (nitromethane, nitroethane, etc.) , Nitrile (acetonitrile, benzonitrile, etc.), ether (chain ether such as diethyl ether, diisopropyl ether, dimethoxyethane; cyclic ether such as tetrahydrofuran, dioxane), ketone (acetone, methyl ethyl ketone) Diisobutyl ketone, etc.), ester (ethyl acetate, butyl acetate, etc.), carbonate (dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), alcohol (methanol, ethanol, propanol, isopropyl alcohol, butanol, etc.), carboxylic acid (acetic acid, etc.) Etc.), and mixed solvents containing these solvents.

  Among these, as the organic solvent used as the precipitation or reprecipitation solvent, a solvent containing at least a hydrocarbon (particularly an aliphatic hydrocarbon such as hexane) is preferable. In such a solvent containing at least hydrocarbon, the ratio of hydrocarbon (for example, aliphatic hydrocarbon such as hexane) and other solvent is, for example, the former / the latter (volume ratio; 25 ° C.) = 10/90 to 99 / 1, preferably the former / the latter (volume ratio; 25 ° C.) = 30/70 to 98/2, more preferably the former / the latter (volume ratio; 25 ° C.) = 50/50 to 97/3.

  The resin composition for photoresists of the present invention contains the polymer compound of the present invention and a photoacid generator.

  Examples of the photoacid generator include conventional or known compounds that efficiently generate acid upon exposure, such as diazonium salts, iodonium salts (for example, diphenyliodohexafluorophosphate), sulfonium salts (for example, triphenylsulfonium hexafluoroantimony). Nates, triphenylsulfonium hexafluorophosphate, triphenylsulfonium methanesulfonate, etc.), sulfonate esters [eg 1-phenyl-1- (4-methylphenyl) sulfonyloxy-1-benzoylmethane, 1,2,3-tri Sulfonyloxymethylbenzene, 1,3-dinitro-2- (4-phenylsulfonyloxymethyl) benzene, 1-phenyl-1- (4-methylphenylsulfonyloxymethyl) -1-hydroxy-1-benzo Rumetan etc.], oxathiazole derivatives, s- triazine derivatives, disulfone derivatives (diphenyl sulfone) imide compound, an oxime sulfonate, a diazonaphthoquinone, and benzoin tosylate. These photoacid generators can be used alone or in combination of two or more.

  The amount of the photoacid generator used can be appropriately selected according to the strength of the acid generated by light irradiation, the ratio of each monomer unit (repeating unit) in the polymer compound, etc., for example, 100 parts by weight of the polymer compound On the other hand, it can be selected from a range of about 0.1 to 30 parts by weight, preferably 1 to 25 parts by weight, and more preferably about 2 to 20 parts by weight.

  The resin composition for photoresist includes alkali-soluble components such as alkali-soluble resins (for example, novolak resins, phenol resins, imide resins, carboxyl group-containing resins), colorants (for example, dyes), organic solvents (for example, Hydrocarbons, halogenated hydrocarbons, alcohols, esters, amides, ketones, ethers, cellosolves, carbitols, glycol ether esters, mixed solvents thereof, etc.) .

  This photoresist resin composition is applied onto a substrate or substrate, dried, and then exposed to light on a coating film (resist film) through a predetermined mask (or further subjected to post-exposure baking). By forming the latent image pattern and then developing it, a fine pattern can be formed with high accuracy.

  Examples of the base material or the substrate include a silicon wafer, metal, plastic, glass, and ceramic. The application of the photoresist resin composition can be performed using a conventional application means such as a spin coater, a dip coater, or a roller coater. The thickness of the coating film is, for example, about 0.01 to 20 μm, preferably about 0.05 to 2 μm.

For exposure, various wavelengths of light such as ultraviolet rays and X-rays can be used. For semiconductor resists, g-line, i-line, and excimer lasers (eg, XeCl, KrF, KrCl, ArF, ArCl, F) are generally used. ₂ , Kr ₂ , KrAr, Ar ₂ etc.). The exposure energy is, for example, about 0.1 to 1000 mJ / cm ² . In the present invention, since the resist film has high water resistance, in addition to normal exposure, exposure can be performed under immersion using an immersion type exposure apparatus. Therefore, it is possible to further advance the pattern miniaturization.

  An acid is generated from the photoacid generator by light irradiation, and this acid causes a protective group (leaving group) such as a carboxyl group of a monomer unit (alkali-soluble unit) having an acid leaving group of the polymer compound. Is rapidly eliminated, and carboxyl groups and the like that contribute to solubilization are generated. Therefore, a predetermined pattern can be accurately formed by development with water or an alkali developer.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

還流管、撹拌子、３方コックを備えた１００ｍｌ丸底フラスコに、窒素雰囲気下、テトラヒドロフラン（ＴＨＦ）１０ｇを入れ、温度を６０℃に保ち、撹拌しながら、６−メタクリロイルオキシヘキサン酸０．２８ｇ（１．４ｍｍｏｌ）、１−（１−メタクリロイルオキシ−１−メチルエチル）アダマンタン４．８７ｇ（１８．６ｍｍｏｌ）、開始剤（和光純薬工業製、商品名「Ｖ−６５」）０．５０ｇ及びＴＨＦ１６ｇを混合したモノマー溶液を２時間かけて一定速度で滴下した。滴下終了後、さらに６時間撹拌を続けた。重合反応終了後、得られた反応液をヘキサンと酢酸エチルの９：１（体積比；２５℃）混合液５００ｍｌ中に撹拌しながら滴下した。生じた沈殿物を濾別し、減圧乾燥（２５℃）することによりすることにより、所望の樹脂３．３ｇを得た。回収したポリマーをＧＰＣ（ゲルパーミエーションクロマトグラフィー）分析したところ、重量平均分子量（Ｍｗ）が８０００、分子量分布（Ｍｗ／Ｍｎ）が２．２であった。なお、６−メタクリロイルオキシヘキサン酸は特開平６−８０６２４号公報に記載の方法に準じて合成した。 Example 1
Synthesis of resin with the following structure

In a 100 ml round bottom flask equipped with a reflux tube, a stirring bar and a three-way cock, 10 g of tetrahydrofuran (THF) was placed under a nitrogen atmosphere, and the temperature was kept at 60 ° C., while stirring, 0.28 g of 6-methacryloyloxyhexanoic acid. (1.4 mmol), 1- (1-methacryloyloxy-1-methylethyl) adamantane 4.87 g (18.6 mmol), initiator (trade name “V-65” manufactured by Wako Pure Chemical Industries, Ltd.) 0.50 g and A monomer solution mixed with 16 g of THF was added dropwise at a constant rate over 2 hours. After completion of the dropwise addition, stirring was continued for 6 hours. After completion of the polymerization reaction, the obtained reaction solution was added dropwise to 500 ml of a 9: 1 (volume ratio; 25 ° C.) mixture of hexane and ethyl acetate while stirring. The resulting precipitate was filtered off and dried under reduced pressure (25 ° C.) to obtain 3.3 g of the desired resin. When the recovered polymer was analyzed by GPC (gel permeation chromatography), the weight average molecular weight (Mw) was 8000, and the molecular weight distribution (Mw / Mn) was 2.2. Incidentally, 6-methacryloyloxyhexanoic acid was synthesized according to the method described in JP-A-6-80624.

還流管、撹拌子、３方コックを備えた１００ｍｌ丸底フラスコに、窒素雰囲気下、テトラヒドロフラン（ＴＨＦ）１０ｇを入れ、温度を６０℃に保ち、撹拌しながら、５−メタクリロイルオキシ−２，６−ノルボルナンカルボラクトン１．３８ｇ（６．２２ｍｍｏｌ）、１−ヒドロキシ−３−メタクリロイルオキシアダマンタン１．４６ｇ（６．１９ｍｍｏｌ）、１−（１−メタクリロイルオキシ−１−メチルエチル）アダマンタン２．１６ｇ（８．２４ｍｍｏｌ）、開始剤（和光純薬工業製、商品名「Ｖ−６５」）０．５０ｇ及びＴＨＦ１６ｇを混合したモノマー溶液を２時間かけて一定速度で滴下した。滴下終了後、さらに６時間撹拌を続けた。重合反応終了後、得られた反応液をヘキサンと酢酸エチルの９：１（体積比；２５℃）混合液５００ｍｌ中に撹拌しながら滴下した。生じた沈殿物を濾別し、減圧乾燥（２５℃）することによりすることにより、所望の樹脂３．４ｇを得た。回収したポリマーをＧＰＣ（ゲルパーミエーションクロマトグラフィー）分析したところ、重量平均分子量（Ｍｗ）が８０００、分子量分布（Ｍｗ／Ｍｎ）が２．１であった。 Comparative Example 1
Synthesis of resin with the following structure

In a 100 ml round bottom flask equipped with a reflux tube, a stirring bar and a three-way cock, 10 g of tetrahydrofuran (THF) was placed under a nitrogen atmosphere, and the temperature was kept at 60 ° C., while stirring, 5-methacryloyloxy-2,6- 1.38 g (6.22 mmol) of norbornanecarbolactone, 1.46 g (6.19 mmol) of 1-hydroxy-3-methacryloyloxyadamantane, 2.16 g of 1- (1-methacryloyloxy-1-methylethyl) adamantane (8. 24 mmol), a monomer solution prepared by mixing 0.50 g of an initiator (trade name “V-65” manufactured by Wako Pure Chemical Industries, Ltd.) and 16 g of THF was added dropwise at a constant rate over 2 hours. After completion of the dropwise addition, stirring was continued for 6 hours. After completion of the polymerization reaction, the obtained reaction solution was added dropwise to 500 ml of a 9: 1 (volume ratio; 25 ° C.) mixture of hexane and ethyl acetate while stirring. The resulting precipitate was filtered off and dried under reduced pressure (25 ° C.) to obtain 3.4 g of the desired resin. When the collected polymer was analyzed by GPC (gel permeation chromatography), the weight average molecular weight (Mw) was 8000, and the molecular weight distribution (Mw / Mn) was 2.1.

Evaluation test 1
About each polymer obtained by the said Example and comparative example, 1.5 g of this polymer was melt | dissolved in 8.5 g of cyclohexanone, 10 g solution was prepared, and it spin-coated on the silicon wafer. The film thickness of the obtained coating film was measured at 5 points by ellipsometry. The silicon wafer on which the coating film was formed was immersed in water at room temperature for 10 minutes and air blown, and then the thickness of the coating film was measured again by the above method. The results are shown in Table 1. In Table 1, the increase value is a value (nm) obtained by subtracting the average value of the film thickness before water immersion from the average value of the film thickness after water immersion.

  As is apparent from Table 1, when the polymer of Example 1 was used, it was found that even when immersed in water, there was almost no variation in the thickness of the coating film and the water resistance was excellent. Therefore, the polymer of Example 1 is useful as a resist for immersion exposure. On the other hand, when the polymer of Comparative Example 1 is used, when it is immersed in water, it swells and the thickness of the coating film increases greatly.

Evaluation test 2
For each of the polymers obtained in the above Examples and Comparative Examples, 100 parts by weight of polymer and 10 parts by weight of triphenylsulfonium hexafluoroantimonate were mixed with propylene glycol monomethyl ether acetate (PGMEA) as a solvent to obtain a polymer concentration. A resin composition for photoresist of 17% by weight was prepared. This composition was applied on a silion wafer by a spin coating method to form a photosensitive layer having a thickness of 0.4 μm. After pre-baking on a hot plate at a temperature of 100 ° C. for 150 seconds, using a KrF excimer laser with a wavelength of 247 nm, exposure was performed at a dose of 30 mJ / cm ² through a mask, followed by post-baking at a temperature of 100 ° C. for 60 seconds. Subsequently, it developed for 60 second with 0.3M tetramethylammonium hydroxide aqueous solution, and rinsed with the pure water. As a result, a 0.20 μm line and space pattern was obtained.

Claims (7)

Formula (I)

(In the formula, Ra represents ^a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms. A represents a linear or branched alkylene having 1 to 20 carbon atoms. A carboxyl group in the formula may be converted to a salt)
A polymer compound comprising: a monomer unit represented by the formula: and a monomer unit having a group that is partly eliminated by an acid and becomes alkali-soluble. A monomer unit having a group that is partially eliminated by an acid and becomes alkali-soluble is represented by the following formulas (IIa) to (IIh):

(In the formula, R ^a represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms or a haloalkyl group having 1 to 6 carbon atoms. R ¹ and R ² are the same or different and have 1 to 8 carbon atoms. R ³ , R ⁴ and R ⁵ are the same or different and represent a hydrogen atom, a hydroxyl group or a methyl group, and R ⁶ and R ⁷ are the same or different and represent a hydrogen atom, a hydroxyl group or shows a -COOR ⁸ group, R ⁸ is t- butyl, 2-tetrahydrofuranyl group, .R ⁹ showing a 2-tetrahydropyranyl group or a 2-oxepanyl group represents a methyl group or an ethyl group, R ¹⁰ and R ¹¹ is the same or different and represents a hydrogen atom, a hydroxyl group or an oxo group, and R ¹² has a substituent having a tertiary carbon atom at the bonding site with the oxygen atom shown in the formula. R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are the same or different and each represents a hydrogen atom or a methyl group, and R ¹⁸ represents a t-butyl group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group or a 2-oxepanyl group. R ¹⁹ and R ²⁰ are the same or different and each represents a hydrogen atom, an alkyl group or a fluoroalkyl group, R ²¹ represents a hydrogen atom or an organic group, m represents an integer of 1 to 3, and n represents 0. Or 1)
The polymer compound according to claim 1, which is at least one monomer unit selected from the group consisting of:   The polymer compound according to claim 1, wherein the monomer unit represented by the formula (I) is 1 to 20 mol% of the total monomer units.   A resin composition for a photoresist, comprising at least the polymer compound according to claim 1 and a photoacid generator.   The resin composition for a photoresist according to claim 4, which is a resin composition for a photoresist for immersion exposure.   A method for producing a semiconductor comprising a step of applying a photoresist resin composition according to claim 4 or 5 onto a substrate or a substrate to form a resist coating film, and forming a pattern through exposure and development. The semiconductor manufacturing method according to claim 6, wherein the exposure is performed under immersion.