JP4781083B2 - Copolymer containing structural unit having 3,4-epoxytricyclo [5.2.1.02,6] decane ring and process for producing the same - Google Patents

Description

The present invention relates to a copolymer containing a structural unit having a 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane ring and a method for producing the same. More specifically, lithography using actinic rays such as far ultraviolet rays, electron beams, ion beams, and X-rays in semiconductor processes, insulating films provided for electronic components such as liquid crystal display elements, integrated circuit elements, solid-state imaging elements, and protection Copolymer containing structural unit having 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane ring suitable as a radiation sensitive resin used as a material for forming a film and the like It relates to the manufacturing method.

  In general, in the field of manufacturing various electronic devices that require fine processing on the order of submicrons, such as VLSI, there is an increasing demand for higher density and higher integration of devices. For this reason, the request | requirement with respect to the photolithographic technique which is a fine pattern formation method is becoming severer. On the other hand, in electronic components such as liquid crystal display elements, integrated circuit elements, solid-state imaging elements, protective films for preventing deterioration and damage, interlayer insulating films provided for insulating between wirings arranged in layers, A flattening film for flattening the element surface, an insulating film for maintaining electrical insulation, and the like are provided. In particular, in the case of a liquid crystal display element, for example, in a TFT type liquid crystal display element, a polarizing plate is provided on a glass substrate, a transparent conductive circuit layer such as ITO and a thin film transistor (TFT) are formed, and covered with an interlayer insulating film. On the other hand, a polarizing plate is provided on the glass plate, a black matrix layer and a color filter layer pattern are formed as necessary, and a transparent conductive circuit layer and an interlayer insulating film are sequentially formed as a top plate. The back plate and the top plate are made to face each other through a spacer and liquid crystal is sealed between the two plates. The photosensitive resin composition used there is transparent, heat resistant, developable and It is required to have excellent flatness.

  As a method for increasing the sensitivity of a resist, a chemically amplified resist using a photoacid generator as a photosensitizer is well known. For example, using a resin composition containing a resin containing a structural unit having an epoxy group and a photoacid generator, a protonic acid is generated from the photoacid generator by exposure, and the epoxy group is cleaved to cause a crosslinking reaction. As a result, the resin becomes insoluble in the developer and a pattern is formed. Further, the resist is moved in the resist solid phase by the heat treatment after the exposure, and the chemical change of the resist resin or the like is amplified catalytically by the acid. . In this way, a dramatic increase in sensitivity has been achieved as compared with conventional resists having a photoreaction efficiency (reaction per photon) of less than 1. Currently, most of the resists that are developed are chemically amplified, and the use of a chemical amplification mechanism is indispensable for the development of high-sensitivity materials that can cope with shorter wavelengths of exposure light sources.

  On the other hand, the insulating film provided in the TFT type liquid crystal display element or the integrated circuit element needs to be finely processed. Therefore, as a material for forming the insulating film, a radiation-sensitive resin composition is generally used. Such a radiation-sensitive resin composition is required to have high radiation sensitivity in order to obtain high productivity. In addition, when the insulating film has low solvent resistance, the insulating film is swelled, deformed, peeled off from the substrate, etc. by an organic solvent, which is serious in the production of liquid crystal display elements and integrated circuit elements. Trouble occurs. Therefore, such an insulating film is required to have excellent solvent resistance. Furthermore, high transparency is required for an insulating film provided in a liquid crystal display element, a solid-state imaging element, or the like as necessary.

  In response to such demands, Japanese Patent Application Laid-Open No. 2003-7612 discloses a photosensitive resin composition containing a copolymer of an alicyclic epoxy group-containing polymerizable unsaturated compound and a radical polymerizable compound. Unsaturated carboxylic acids and the like are used as radically polymerizable compounds. Epoxy compounds are effective in obtaining a film having good etching resistance by easily crosslinking with an acid generated by a photoacid generator and subsequent heating (post-bake) in a light amplification type resist. However, while the alicyclic epoxy group-containing polymerizable unsaturated compound is rich in cationic polymerizability, it easily reacts with a carboxyl group derived from an unsaturated carboxylic acid used for imparting alkali solubility, and has poor storage stability. It was necessary to store at a low temperature of −20 ° C. or lower, and there was a big problem in practicality.

  Japanese Patent No. 3055495 discloses a monomer unit corresponding to a (meth) acrylic ester in which a bridged cyclic hydrocarbon group is directly bonded to an oxygen atom of an ester, a monomer unit having an epoxy group-containing hydrocarbon group, and A photosensitive resin composition containing a copolymer composed of a monomer unit having a carboxyl group is disclosed. However, the (meth) acrylic acid ester in which the bridged cyclic hydrocarbon group is directly bonded to the oxygen atom of the ester has a very bulky group at the adjacent position of the ester group, so that monomer synthesis is often difficult, Furthermore, it is poorly soluble in organic solvents, and it is difficult to handle the resulting resin during the polymerization reaction. In addition, since the (meth) acrylic acid ester in which the bridged cyclic hydrocarbon group is directly bonded to the oxygen atom of the ester has a very low polarity, when copolymerizing with a highly polar unsaturated carboxylic acid or an epoxy group-containing monomer, There is a case where the monomer composition of the polymer is biased and a polymer having a uniform composition cannot be obtained, and thus the desired resist performance cannot be obtained.

JP 2003-7612 A Japanese Patent No. 3055495

  The object of the present invention is that when used as a radiation sensitive resin, it is excellent in solvent solubility and can form a high performance film having transparency, heat resistance, etching resistance, flatness and developability, and An object of the present invention is to provide a polymer having a very high storage stability of a resin composition containing a resin and easy to synthesize, and a method for producing the same.

  As a result of diligent studies to achieve the above object, the present inventors have obtained a monomer mixture comprising a polymerizable unsaturated compound having an alkali-soluble group and a specific amount of a specific epoxy group-containing polymerizable unsaturated compound, or A polymer obtained by copolymerizing a monomer mixture composed of these and a specific polymerizable unsaturated compound is excellent in solvent solubility, extremely good storage stability of a solution, and has transparency, heat resistance, The inventors have found that a film excellent in etching resistance, flatness, developability and the like can be formed, and completed the present invention.

式中、Ｒ¹は水素原子又は炭素数１〜７のアルキル基を示し、Ｒ²は炭素数１〜１２の第１級若しくは第２級アルキル基、炭素数２〜１２のアルケニル基、アリール基、アラルキル基、４員環以上の環状エーテル含有基又は−（Ｒ³−Ｏ）_m−Ｒ⁴基（式中、Ｒ³は炭素数１〜１２の２価の炭化水素基、Ｒ⁴は水素原子又は炭化水素基、ｍは１以上の整数を示す）を示す］
で表される不飽和カルボン酸エステル、及び（c3）Ｎ−置換マレイミドからなる群より選択された少なくとも１種のエポキシ基非含有重合性不飽和化合物に対応するモノマー単位からなり、数平均分子量が３０００〜５００００である共重合体であって、前記モノマー単位（Ｂ）の割合が全モノマー単位に対して４０〜９０重量％であり、且つ前記モノマー単位（Ｂ）のうち３０重量％以上が、下記式（2a）及び（2b）

（式中、Ｒ⁵は、それぞれ、水素原子又はヒドロキシル基で置換されていてもよい炭素数１〜７のアルキル基を示し、Ａは、それぞれ、単結合又はヘテロ原子を含んでいてもよい２価の炭化水素基を示す）
で表される３，４−エポキシトリシクロ［５．２．１．０^2,6］デカン環含有化合物から選択された少なくとも１種の化合物に対応するモノマー単位であることを特徴とする共重合体を提供する。 That is, the present invention is substituted with (A) an alkali monomeric units containing soluble group and (B) in addition to the monomer units of which corresponds to epoxy-containing polymerizable unsaturated compound (C) (c1) an alkyl group Styrene, (c2) Formula (1)

In the formula, R ¹ represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms, R ² represents a primary or secondary alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an aryl group. , An aralkyl group, a cyclic ether-containing group having 4 or more members, or — (R ³ —O) _m —R ⁴ group (wherein R ³ is a divalent hydrocarbon group having 1 to 12 carbon atoms, R ⁴ is hydrogen An atom or a hydrocarbon group, m represents an integer of 1 or more]
In the unsaturated carboxylic acid ester represented, and (c3) Ri Do from at least one monomer unit corresponding to the epoxy group-free polymerizable unsaturated compound selected from the group consisting of N- substituted maleimide, a number average molecular weight In which the proportion of the monomer units (B) is 40 to 90% by weight with respect to the total monomer units, and 30% by weight or more of the monomer units (B). The following formulas (2a) and (2b)

(In the formula, each R ⁵ represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms which may be substituted with a hydroxyl group, and A may include a single bond or a hetero atom, respectively. Valent hydrocarbon group)
A monomer unit corresponding to at least one compound selected from 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane ring-containing compounds represented by Provide coalescence.

  In this copolymer, the proportion of the monomer unit (A) is preferably in the range of 10 to 50% by weight with respect to the total monomer units. This copolymer can be suitably used as an alkaline aqueous solution-soluble photoresist resin.

［式中、Ｒ¹は水素原子又は炭素数１〜７のアルキル基を示し、Ｒ²は炭素数１〜１２の第１級若しくは第２級アルキル基、炭素数２〜１２のアルケニル基、アリール基、アラルキル基、４員環以上の環状エーテル含有基又は−（Ｒ³−Ｏ−）_mＲ⁴基（式中、Ｒ³は炭素数１〜１２の２価の炭化水素基、Ｒ⁴は水素原子又は炭化水素基、ｍは１以上の整数を示す）を示す］
で表される不飽和カルボン酸エステル、及び（c3）Ｎ−置換マレイミドからなる群より選択された少なくとも１種のエポキシ基非含有重合性不飽和化合物からなる単量体混合物であって、前記エポキシ基含有重合性不飽和化合物（ｂ）の割合が単量体の総量に対して４０〜９０重量％であり、且つ前記エポキシ基含有重合性不飽和化合物（ｂ）のうち３０重量％以上が、下記式（2a）及び（2b）

（式中、Ｒ⁵は、それぞれ、水素原子又はヒドロキシル基で置換されていてもよい炭素数１〜７のアルキル基を示し、Ａは、それぞれ、単結合又はヘテロ原子を含んでいてもよい２価の炭化水素基を示す）
で表される３，４−エポキシトリシクロ［５．２．１．０^2,6］デカン環含有化合物から選択された少なくとも１種の化合物である単量体混合物を共重合に付すことを特徴とする共重合体の製造法を提供する。
なお、本明細書では、上記発明のほか、
（Ａ）アルカリ可溶性基を含むモノマー単位及び（Ｂ）エポキシ基含有重合性不飽和化合物に対応するモノマー単位からなる共重合体、又は前記モノマー単位（Ａ）及び（Ｂ）に加えて（Ｃ）（c1）アルキル基で置換されていてもよいスチレン、（c2）前記式（１）で表される不飽和カルボン酸エステル、及び（c3）Ｎ−置換マレイミドからなる群より選択された少なくとも１種のエポキシ基非含有重合性不飽和化合物に対応するモノマー単位からなる共重合体であって、前記モノマー単位（Ｂ）の割合が全モノマー単位に対して４０〜９０重量％であり、且つ前記モノマー単位（Ｂ）のうち３０重量％以上が、前記式（2a）及び（2b）で表される３，４−エポキシトリシクロ［５．２．１．０ ^2,6 ］デカン環含有化合物から選択された少なくとも１種の化合物に対応するモノマー単位であることを特徴とする共重合体、についても説明する。
また、本明細書では、上記発明のほか、
（ａ）アルカリ可溶性基を有する重合性不飽和化合物及び（ｂ）エポキシ基含有重合性不飽和化合物からなる単量体混合物であって、前記エポキシ基含有重合性不飽和化合物（ｂ）の割合が単量体の総量に対して４０〜９０重量％であり、且つ前記エポキシ基含有重合性不飽和化合物（ｂ）のうち３０重量％以上が、前記式（2a）及び（2b）で表される３，４−エポキシトリシクロ［５．２．１．０ ^2,6 ］デカン環含有化合物から選択された少なくとも１種の化合物である単量体混合物を共重合に付すことを特徴とする共重合体の製造法、についても説明する。 In the present invention, in addition to (a) a polymerizable unsaturated compound having an alkali-soluble group and (b) an epoxy group-containing polymerizable unsaturated compound , (c) (c1) may be substituted with an alkyl group. Styrene, (c2) Formula (1)

[Wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms, R ² represents a primary or secondary alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, aryl Group, aralkyl group, 4-membered or higher cyclic ether-containing group or-(R ³ -O-) _m R ⁴ group (wherein R ³ is a divalent hydrocarbon group having 1 to 12 carbon atoms, R ⁴ is A hydrogen atom or a hydrocarbon group, m represents an integer of 1 or more]
And (c3) a monomer mixture consisting of at least one epoxy group-free polymerizable unsaturated compound selected from the group consisting of (c3) N-substituted maleimides, The proportion of the group-containing polymerizable unsaturated compound (b) is 40 to 90% by weight with respect to the total amount of monomers, and 30% by weight or more of the epoxy group-containing polymerizable unsaturated compound (b) Following formula (2a) and (2b)

(In the formula, each R ⁵ represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms which may be substituted with a hydroxyl group, and A may include a single bond or a hetero atom, respectively. Valent hydrocarbon group)
And a monomer mixture which is at least one compound selected from 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane ring-containing compounds represented by the formula: A method for producing a copolymer is provided.
In this specification, in addition to the above invention,
(A) a monomer unit containing an alkali-soluble group and (B) a copolymer comprising monomer units corresponding to an epoxy group-containing polymerizable unsaturated compound, or in addition to the monomer units (A) and (B) (C) (C1) at least one selected from the group consisting of styrene optionally substituted with an alkyl group, (c2) an unsaturated carboxylic acid ester represented by the above formula (1), and (c3) N-substituted maleimide A copolymer comprising monomer units corresponding to the epoxy group-free polymerizable unsaturated compound, wherein the proportion of the monomer units (B) is 40 to 90% by weight with respect to the total monomer units, and 30% by weight or more of the unit (B) is selected from the 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane ring-containing compound represented by the formulas (2a) and (2b). At least Copolymer which is a monomer unit corresponding to one compound, also described.
In addition to the above invention, in this specification,
(A) a monomer mixture comprising a polymerizable unsaturated compound having an alkali-soluble group and (b) an epoxy group-containing polymerizable unsaturated compound, wherein the proportion of the epoxy group-containing polymerizable unsaturated compound (b) is It is 40 to 90% by weight based on the total amount of monomers, and 30% by weight or more of the epoxy group-containing polymerizable unsaturated compound (b) is represented by the formulas (2a) and (2b). Copolymerization characterized by subjecting a monomer mixture which is at least one compound selected from 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane ring-containing compound to copolymerization A method for producing the coalescence will also be described.

  According to the copolymer of the present invention, the solvent solubility is excellent, the storage stability is very good, transparency (for example, transparency to light of 180 to 400 nm), heat resistance, etching resistance, flatness, A film excellent in developability and the like can be formed. Therefore, it is extremely useful as a photoresist resin or the like.

  The monomer unit (A) containing an alkali-soluble group has a function of imparting alkali solubility to the polymer. As a result, the polymer is dissolved in an alkaline aqueous solution (developer) during development. In addition, the monomer unit (A) has a hardness required as a resist for the film by curing the polymer by crosslinking with a crosslinking agent or by reaction with an epoxy group or an oxetane ring-containing group in the polymer molecule at the time of exposure. And has the function of changing the polymer to alkali-insoluble. Therefore, the copolymer of the present invention is particularly useful as a negative photoresist resin.

  The monomer unit (A) containing an alkali-soluble group can be introduced into the polymer by subjecting the polymerizable unsaturated compound (a) having an alkali-soluble group to copolymerization. The alkali-soluble group may be a group usually used in the resist field, and examples thereof include a carboxyl group and a phenolic hydroxyl group. Representative examples of the polymerizable unsaturated compound (a) having an alkali-soluble group include, but are not limited to, an unsaturated carboxylic acid or an acid anhydride thereof, hydroxystyrene or a derivative thereof. Among these, unsaturated carboxylic acid or its acid anhydride is particularly preferable.

  Examples of unsaturated carboxylic acids or acid anhydrides thereof include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, and acid anhydrides thereof (maleic anhydride, An itaconic anhydride, etc.). Among these, acrylic acid and methacrylic acid are particularly preferable. The polymerizable unsaturated compound (a) having an alkali-soluble group can be used alone or in combination of two or more.

  The proportion of the monomer unit (A) containing an alkali-soluble group in the copolymer varies depending on the type of monomer used and the type of resist (negative type or positive type), but usually all monomer units constituting the copolymer. Is 10 to 50% by weight, preferably 12 to 40% by weight, and more preferably 14 to 30% by weight. If this ratio is too small, it is difficult to dissolve in an alkali developer and the developability deteriorates. Conversely, if it is too large, the etching resistance after development deteriorates, which is not preferable.

  The monomer unit (B) corresponding to the epoxy group-containing polymerizable unsaturated compound has an alkali-soluble group (for example, a carboxyl group, a phenolic hydroxyl group, etc.) present in the polymer molecule by crosslinking using a crosslinking agent during exposure. In this reaction, the polymer is cured, the film is imparted with the necessary hardness as a resist, the etching resistance is increased, and the polymer is changed to alkali-insoluble.

  The monomer unit (B) corresponding to the epoxy group-containing polymerizable unsaturated compound can be introduced into the polymer by subjecting the epoxy group-containing polymerizable unsaturated compound (b) to copolymerization. The epoxy group-containing polymerizable unsaturated compound (b) is preferably a compound having a polycyclic aliphatic group having an epoxy group on the ring and a group having an unsaturated bond. Examples of the polycyclic aliphatic group include a dicyclopentanyl group and a tricyclodecyl group. Examples of the unsaturated bond include a carbon-carbon double bond, and examples of the group having an unsaturated bond include a vinyl group, an allyl group, a methallyl group, an acryloyl group, and a methacryloyl group.

In the present invention, the epoxy group-containing polymerizable unsaturated compound (b) is at least 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] represented by the above formulas (2a) and (2b). At least one compound selected from decane ring-containing compounds is used. In formulas (2a) and (2b), R ⁵ represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms which may be substituted with a hydroxyl group, and A represents a single bond or a hetero atom, respectively. The divalent hydrocarbon group which may be contained is shown.

Examples of the alkyl group having 1 to 7 carbon atoms which may be substituted with a hydroxyl group in R ⁵ include alkyl such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, hexyl and heptyl groups. Group: hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 1-hydroxy-1-methylethyl group, 2-hydroxy- Examples thereof include hydroxyalkyl groups such as 1-methylethyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group and 4-hydroxybutyl group. R ⁵ is preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may be substituted with a hydroxyl group, and particularly preferably a hydrogen atom or a methyl group.

  In the divalent hydrocarbon group which may contain a hetero atom in A, the hetero atom may be bonded to the terminal of the hydrocarbon group or may be interposed between carbon atoms constituting the hydrocarbon group. . Examples of the hetero atom include nitrogen, oxygen, sulfur atom and the like.

（式中、Ｒ⁶は炭素数１〜１２の２価の炭化水素基を示し、ｎは０以上の整数を示す）
で表される基が挙げられる。 As a typical example of A, the following formula (3)

(In the formula, R ⁶ represents a divalent hydrocarbon group having 1 to 12 carbon atoms, and n represents an integer of 0 or more.)
The group represented by these is mentioned.

Examples of the divalent hydrocarbon group having 1 to 12 carbon atoms in R ⁶ include divalent linear groups such as methylene, ethylene, propylene, trimethylene, tetramethylene, hexamethylene, octamethylene, decamethylene, and dodecamethylene groups. Or a branched alkylene group; a divalent alicyclic hydrocarbon group such as cyclopentylene, cyclohexylene, cyclopentylidene, cyclohexylidene (a cycloalkylene group, a cycloalkylidene group, a divalent bridged carbocyclic group A divalent hydrocarbon group in which two or more of these are bonded. R ⁶ is particularly preferably a C 1-6 alkylene group such as methylene, ethylene, propylene, tetramethylene or hexamethylene group; a 3-6 membered alicyclic hydrocarbon group such as cyclohexylene group. n is preferably an integer of 0 to 10, more preferably an integer of 0 to 4, particularly preferably 0 or 1.

  Other typical examples of A include alkylene groups such as a methylene group, an ethylene group, a propylene group, and a trimethylene group (for example, an alkylene group having 1 to 12 carbon atoms, particularly an alkylene group having 1 to 6 carbon atoms); a thiomethylene group. Thioalkylene groups such as thioethylene groups and thiopropylene groups (for example, thioalkylene groups having 1 to 12 carbon atoms, particularly thioalkylene groups having 1 to 6 carbon atoms); aminomethylene groups, aminoethylene groups, aminopropylene groups, etc. Examples thereof include aminoalkylene groups (for example, aminoalkylene groups having 1 to 12 carbon atoms, particularly aminoalkylene groups having 1 to 6 carbon atoms).

A is preferably a single bond [when n is 0 in the above formula (a)], an alkylene group having 1 to 6 carbon atoms (particularly 1 to 3 carbon atoms), or 1 to 6 carbon atoms (particularly carbon). 2 to 3) oxyalkylene group [in the formula (a), n is 1 and R ⁶ is a C _1-6 alkylene group (particularly a C _2-3 alkylene group)], more preferably, It is a single bond or an oxyethylene group.

As a representative example of the 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane ring-containing compound represented by the formula (2a) or (2b), an epoxidized dicyclopentenyl (meth) Acrylate [3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl (meth) acrylate; 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] Decan-8-yl (meth) acrylate], epoxidized dicyclopentenyloxyethyl (meth) acrylate [2- (3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yloxy ) Ethyl (meth) acrylate; 2- (3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yloxy) ethyl (meth) acrylate], epoxidized dicyclopentenyloxybutyl ( Meta) Acrelay , Epoxidized dicyclopentenyloxyethyl hexyl (meth) acrylate. Of these, epoxidized dicyclopentenyl (meth) acrylate and epoxidized dicyclopentenyloxyethyl (meth) acrylate are particularly preferred.

  The compound represented by the formula (2a) and the compound represented by the formula (2b) can be used alone. Moreover, they can be mixed and used in arbitrary ratios. When both are used as a mixture, the ratio is preferably the formula (2a): formula (2b) = 5: 95 to 95: 5, more preferably 10:90 to 90:10, still more preferably 20:80. ~ 80: 20.

In the present invention, the 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane ring-containing compound represented by the formulas (2a) and (2b) and other epoxy group-containing polymerizable groups are not included. A saturated compound (hereinafter may be referred to as “another epoxy group-containing polymerizable unsaturated compound”) may be used in combination. Other epoxy group-containing polymerizable unsaturated compounds include, for example, oxiranyl (meth) acrylate, glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, 2-ethylglycidyl (meth) acrylate, and 2-oxiranyl. Polymerizable unsaturated compounds containing an oxirane ring (monocyclic) such as ethyl (meth) acrylate, 2-glycidyloxyethyl (meth) acrylate, 3-glycidyloxypropyl (meth) acrylate, glycidyloxyphenyl (meth) acrylate (( Meth) acrylic acid ester derivatives, etc.); 3,4-epoxycyclohexyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 2- (3,4-epoxycyclohexyl) ethyl (meth) acrylate, 2- (3 -Includes epoxy group-containing alicyclic carbocycles such as 3,4-epoxycyclohexane rings such as epoxycyclohexylmethyloxy) ethyl (meth) acrylate and 3- (3,4-epoxycyclohexylmethyloxy) propyl (meth) acrylate Polymerizable unsaturated compounds (such as (meth) acrylic acid ester derivatives); 5,6-epoxy-2-bicyclo [2] such as 5,6-epoxy-2-bicyclo [2.2.1] heptyl (meth) acrylate 2.1] Polymerizable unsaturated compounds (such as (meth) acrylic acid ester derivatives) containing a heptane ring. As another epoxy group-containing polymerizable unsaturated compound, a vinyl ether compound containing an epoxy group, an allyl ether compound containing an epoxy group, or the like can be used.

  The proportion of the monomer unit (B) corresponding to the epoxy group-containing polymerizable unsaturated compound in the copolymer is 40 to 90% by weight, preferably 45 to 85% by weight, more preferably, based on the total monomer units. 50 to 80% by weight. If this ratio is less than 40% by weight, the crosslinking reaction at the time of exposure does not proceed sufficiently, and the heat resistance and etching resistance are poor. On the other hand, if the ratio exceeds 90% by weight, the alkali solubility becomes insufficient and a good pattern cannot be formed.

In the present invention, 3,4-epoxytricyclo [5.2.] Represented by the above formulas (2a) and (2b) in the monomer unit (B) corresponding to the epoxy group-containing polymerizable unsaturated compound. 1.0 ^2,6 ] The proportion of monomer units corresponding to the decane ring-containing compound is 30% by weight or more in total. When this ratio is less than 30% by weight, for example, when used in combination with a polymerizable unsaturated compound containing an epoxy group-containing alicyclic carbocycle, the storage stability is deteriorated, and a polymerizable non-polymerizable compound containing an oxirane ring (monocycle) is deteriorated. When used in combination with a saturated compound (such as a glycidyl group-containing monomer), the performance required for the radiation-sensitive resin becomes insufficient, such as insufficient heat resistance.

  In the present invention, the monomer unit (C) is (c1) styrene optionally substituted with an alkyl group, (c2) an unsaturated carboxylic acid ester represented by the formula (1), and (c3) N-substituted. It is a monomer unit corresponding to at least one non-epoxy group-containing polymerizable unsaturated compound selected from the group consisting of maleimides. The monomer unit (C) has a function of imparting a necessary hardness as a resist to the film, and a monomer corresponding thereto has a function of facilitating the copolymerization reaction. Further, depending on the type, it also has a function of increasing the hardness of the film by a crosslinking reaction or the like.

  Examples of the alkyl group in styrene (c1) which may be substituted with an alkyl group include alkyl groups having about 1 to 7 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, hexyl groups and the like. Is mentioned. Among these, an alkyl group having 1 to 4 carbon atoms such as a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable. The alkyl group may be bonded to either the vinyl group of styrene or the benzene ring. Representative examples of styrene (c1) optionally substituted with an alkyl group include styrene, α-methylstyrene, vinyltoluene (o-vinyltoluene, m-vinyltoluene, p-vinyltoluene) and the like. These can be used alone or in combination of two or more.

In the unsaturated carboxylic acid ester (c2) represented by the formula (1), examples of the alkyl group having 1 to 7 carbon atoms in R ¹ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, A hexyl group etc. are mentioned. R ¹ is particularly preferably a hydrogen atom or a methyl group.

Examples of the primary or secondary alkyl group having 1 to 12 carbon atoms in R ² include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, hexyl, octyl, decyl, dodecyl groups and the like. It is done. Examples of the alkenyl group having 2 to 12 carbon atoms include primary or secondary alkenyl groups such as allyl, 3-butenyl, and 5-hexenyl groups. Examples of the aryl group include a phenyl group. Examples of the aralkyl group include a benzyl group. Examples of the 4-membered or higher cyclic ether-containing group include groups containing a cyclic ether structure such as an oxetane ring, an oxolane ring, an oxane ring, and an oxepane ring. Examples of the oxetane ring-containing group include oxetanyl group, 3-methyl-3-oxetanyl group, 3-ethyl-3-oxetanyl group, (3-methyl-3-oxetanyl) methyl group, and (3-ethyl-3-oxetanyl). ) Methyl group, 2- (3-methyl-3-oxetanyl) ethyl group, 2- (3-ethyl-3-oxetanyl) ethyl group, 2-[(3-methyl-3-oxetanyl) methyloxy] ethyl group, 2-[(3-ethyl-3-oxetanyl) methyloxy] ethyl group, 3-[(3-methyl-3-oxetanyl) methyloxy] propyl group, 3-[(3-ethyl-3-oxetanyl) methyloxy Propyl group and the like. Examples of the oxolane ring-containing group include a tetrahydrofurfuryl group, a 3-oxolanyl group, a 3-methyl-3-oxolanyl group, a 3-ethyl-3-oxolanyl group, a (2-methyl-2-oxolanyl) methyl group, (2 -Ethyl-2-oxolanyl) methyl group, 2- (2-methyl-2-oxolanyl) ethyl group, 2- (2-ethyl-2-oxolanyl) ethyl group, 2-[(2-methyl-2-oxolanyl) Methyloxy] ethyl group, 2-[(2-ethyl-2-oxolanyl) methyloxy] ethyl group, 3-[(2-methyl-2-oxolanyl) methyloxy] propyl group, 3-[(2-ethyl- 2-oxolanyl) methyloxy] propyl group, and the like.

In R ² — (R ³ —O) _m —R ⁴ group, R ³ is a divalent hydrocarbon group having 1 to 12 carbon atoms, R ⁴ is a hydrogen atom or a hydrocarbon group, m is an integer of 1 or more. Show. As said C1-C12 bivalent hydrocarbon group, the same thing as the C1-C12 bivalent hydrocarbon group in said R < ⁶ > is mentioned. Of these, an alkylene group having 2 to 6 carbon atoms such as ethylene, propylene, tetramethylene and hexamethylene groups; a 3 to 6 membered alicyclic hydrocarbon group such as cyclohexylene group and the like are particularly preferable. Examples of the hydrocarbon group in R ⁴ include aliphatic hydrocarbon groups such as alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, and hexyl groups (eg, C _1-6 alkyl groups); cyclopentyl groups and cyclohexyl groups. Alicyclic carbonization such as bridged carbocyclic groups such as cycloalkyl groups, norbornyl groups (bicyclo [2.2.1] heptyl group) and tricyclo [5.2.1.0 ^2,6 ] decyl groups A hydrogen group; a group in which two or more of these are bonded. m is preferably an integer of 1 to 10, more preferably an integer of 1 to 4, and particularly preferably 1.

Representative examples of the unsaturated carboxylic acid ester (c2) represented by the formula (1) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meta ) Acrylate, allyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, oxetanyl (meth) acrylate, 3-methyl-3-oxetanyl (meth) acrylate, 3-ethyl-3-oxetanyl (meth) acrylate , (3-methyl-3-oxetanyl) methyl (meth) acrylate, (3-ethyl-3-oxetanyl) methyl (meth) acrylate, 2- (3-methyl-3-oxetanyl) ethyl (meth) acrylate, 2- (3-Ethyl-3-oxetanyl) ethyl ( ) Acrylate, 2-[(3-methyl-3-oxetanyl) methyloxy] ethyl (meth) acrylate, 2-[(3-ethyl-3-oxetanyl) methyloxy] ethyl (meth) acrylate, 3-[( 3-methyl-3-oxetanyl) methyloxy] propyl (meth) acrylate, 3-[(3-ethyl-3-oxetanyl) methyloxy] propyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, tetrahydrofurfuryl (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- (tricyclo [5.2.1.0 ^2,6 ] decyloxy) ethyl (meth) acrylate and the like. The unsaturated carboxylic acid ester (c2) represented by the formula (1) can be used alone or in combination of two or more.

［式中、Ｒ⁷は有機基を示す］
で表される化合物などを使用できる。 As N-substituted maleimide (c3), the following formula (4)

[Wherein R ⁷ represents an organic group]
The compound etc. which are represented by these can be used.

The organic group includes a hydrocarbon group and a heterocyclic group. Examples of the hydrocarbon group include aliphatic hydrocarbon groups such as alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, and hexyl groups (eg, C _1-6 alkyl groups); cyclopentyl groups, cyclohexyl groups, and cyclooctyl groups. An alicyclic hydrocarbon group such as a bridged carbocyclic group such as a cycloalkyl group such as a group, an adamantyl group or a norbornyl group; an aryl group such as a phenyl group; an aralkyl group such as a benzyl group; Etc. Examples of the heterocyclic group include a non-aromatic or aromatic heterocyclic ring having about 5 to 10 members and containing at least one heteroatom selected from the group consisting of a nitrogen atom, an oxygen atom and a sulfur atom. And a formula group.

  Representative examples of N-substituted maleimide (c3) include, for example, N-cycloalkylmaleimides such as N-cyclopentylmaleimide, N-cyclohexylmaleimide, N-cyclooctylmaleimide; N-adamantylmaleimide, N-norbornylmaleimide N-bridged carbocyclic group-substituted maleimide such as: N-methylmaleimide, N-ethylmaleimide, N-alkylmaleimide such as N-propylmaleimide; N-arylmaleimide such as N-phenylmaleimide; N-benzylmaleimide N-aralkylmaleimide and the like. Among these, N-cycloalkylmaleimide such as N-cyclohexylmaleimide, N-bridged carbocyclic group-substituted maleimide, and the like are preferable. N-substituted maleimide (c3) can be used alone or in combination of two or more.

  The copolymer of the present invention may contain a small amount of other monomer units in addition to the monomer unit (A), monomer unit (B), and monomer unit (C). Examples of the monomer unit include units corresponding to (meth) acrylamide, (meth) acrylonitrile and the like. When the copolymer of the present invention includes the monomer unit (A) and the monomer unit (B) and does not include the monomer unit (C), the total amount of the monomer unit (A) and the monomer unit (B) is The amount is usually 98% by weight or more, preferably 99% by weight or more, and more preferably substantially 100% by weight with respect to all monomer units. Further, when the copolymer of the present invention includes the monomer unit (A), the monomer unit (B), and the monomer unit (C), the total amount of these three types of monomer units is based on the total monomer units. For example, it is 90% by weight or more, preferably 95% by weight or more, more preferably 98% by weight or more, and particularly preferably substantially 100% by weight.

The copolymer of the present invention is a monomer mixture comprising the polymerizable unsaturated compound (a) having an alkali-soluble group and the epoxy group-containing polymerizable unsaturated compound (b), or the above (a) and (b). In addition to the epoxy group-containing polymerizable unsaturated compound (c), wherein the ratio of the epoxy group-containing polymerizable unsaturated compound (b) is 40 with respect to the total amount of monomers. 3,4-epoxytricyclo [, wherein 90 wt% or more of the epoxy group-containing polymerizable unsaturated compound (b) is represented by the formula (2a) and / or (2b). 5.2.1.0 ^2,6 ] It can be produced by subjecting a monomer mixture that is a decane ring-containing compound to copolymerization.

  As a polymerization initiator used for copolymerization, a normal radical polymerization initiator can be used. For example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis (2-methylpropionate), diethyl-2,2'-azobis (2-methylpro) Pionate), azo compounds such as dibutyl-2,2'-azobis (2-methylpropionate), benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1-bis (t-butylperoxy) Examples include organic peroxides such as cyclohexane, hydrogen peroxide, and the like. When a peroxide is used as a radical polymerization initiator, a redox initiator may be combined with a reducing agent. Of these, azo compounds are preferred, and in particular, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis (2- Methyl propionate) is preferred.

  The amount of the polymerization initiator used can be appropriately selected within the range not impairing the smooth copolymerization, but is usually about 1 to 10% by weight based on the total amount of the monomers (total monomer components) and the polymerization initiator. It is preferably about 2 to 8% by weight.

  The copolymerization can be performed by a conventional method used for producing a styrene polymer or an acrylic polymer, such as solution polymerization, bulk polymerization, suspension polymerization, bulk-suspension polymerization, and emulsion polymerization. Among these, solution polymerization is preferable. The monomer and the polymerization initiator may be supplied all at once to the reaction system, or a part or all of them may be dropped into the reaction system. For example, a method in which a solution in which a polymerization initiator is dissolved in a polymerization solvent is dropped into a mixed solution of a monomer and a polymerization solvent kept at a constant temperature, or the monomer and the polymerization initiator are dissolved in the polymerization solvent in advance. A method in which the solution is dropped into a polymerization solvent maintained at a constant temperature for polymerization (drop polymerization method) can be employed.

  The polymerization solvent can be appropriately selected according to the monomer composition and the like. Examples of the polymerization solvent include ethers (chain ethers such as diethyl ether, 3-methoxy-1-butanol, glycol ethers such as propylene glycol monomethyl ether and diethylene glycol ethyl methyl ether, and cyclic ethers such as tetrahydrofuran and dioxane), esters. (Methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, 3-methoxybutyl acetate, ethyl-3-ethoxypropionate, glycol ether esters such as propylene glycol monomethyl ether acetate, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl) Ketone, cyclohexanone, etc.), amide (N, N-dimethylacetamide, N, N-dimethylformamide, etc.), sulfoxide (dimethylsulfoxide) Etc.), alcohol (methanol, ethanol, propanol, etc.), hydrocarbon (aromatic hydrocarbons such as benzene, toluene, xylene, aliphatic hydrocarbons such as hexane, alicyclic hydrocarbons such as cyclohexane, etc.), and mixtures thereof A solvent etc. are mentioned. The polymerization temperature can be appropriately selected within a range of about 30 to 150 ° C., for example.

  The copolymer of this invention produces | generates by the said method. The number average molecular weight of the copolymer is, for example, 3000 to 50000, preferably 3500 to 40000, and more preferably about 4000 to 30000. The degree of dispersion (weight average molecular weight Mw / number average molecular weight Mn) of the copolymer is about 1 to 3.

  The polymerization solution obtained by the above method is adjusted to a solid content concentration or subjected to a filtration treatment as necessary, and then to this, a photoacid generator, a crosslinking agent (in the case of a negative resist), a resin, a coloring By adding an appropriate additive such as an agent, it can be used as a radiation sensitive resin composition such as a resin composition for a photoresist. In addition, the polymer produced by the polymerization is purified by precipitation or reprecipitation, and the purified polymer is dissolved in a solvent such as a resist solvent together with the appropriate additive to thereby improve the sensitivity of the resin composition for photoresist. It can also be used as a radiation resin composition. As the additive such as the photoacid generator and the crosslinking agent and the solvent for the resist, those generally used in the resist field can be used depending on the monomer composition and the like.

  The solvent used for polymer precipitation or reprecipitation may be either an organic solvent or water, or a mixed solvent thereof. Examples of organic solvents include hydrocarbons (aliphatic hydrocarbons such as pentane, hexane, heptane, and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene), 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.), nitriles (acetonitrile, benzonitrile) Etc.), ethers (chain ethers such as diethyl ether, diisopropyl ether and dimethoxyethane; cyclic ethers such as tetrahydrofuran and dioxane), ketones (acetone, methyl ethyl ketone, diisobutyl ketone, etc.), Tell (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.), these Examples thereof include a mixed solvent containing a solvent.

Thus obtained copolymer, a radiation-sensitive resin, for example, g-ray exposure, i-rays, excimer laser (e.g., XeCl, KrF, KrCl, ArF , ArCl, F 2, Kr 2, KrAr, Ar 2 , etc.) It is suitably used as a photoresist resin using, for example, an alkaline aqueous solution-soluble photoresist resin (negative photoresist resin).

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. The viscosities of the copolymer solution and the radiation sensitive resin composition solution were measured with a B-type viscometer. Moreover, the weight average molecular weight (polystyrene conversion) and dispersity (weight average molecular weight Mw / number average molecular weight Mn) of the copolymer were measured using a GPC (gel permeation chromatography) apparatus (trade name “K2479” manufactured by Shimadzu Corporation). )). The analysis conditions are as follows.
Column: SHIMADZU Shim-pack GPC-80M
Eluent: THF (tetrahydrofuran) 1 ml / min
Temperature (oven): 40 ° C
Detector: RI

Example 1
A 1 L flask equipped with a reflux condenser, a dropping funnel and a stirrer is flowed with a suitable amount of nitrogen to form a nitrogen atmosphere, and 200 parts by weight of 3-methoxy-1-butanol and 105 parts by weight of 3-methoxybutyl acetate are added and stirred. While heating to 70 ° C. Next, in the flask, 55 parts by weight of methacrylic acid (MAA), 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (compound contained in formula (2a)) ) And 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] (E -DCPA) A solution prepared by dissolving 175 parts by weight and 70 parts by weight of N-cyclohexylmaleimide (CHMI) in 140 parts by weight of 3-methoxybutyl acetate was added dropwise over about 4 hours using a dropping pump. On the other hand, a solution prepared by dissolving 30 parts by weight of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) in 225 parts by weight of 3-methoxybutyl acetate was dropped over about 5 hours using another dropping pump. did. After completion of the dropping of the polymerization initiator, the temperature is maintained at the same temperature for about 4 hours, and then cooled to room temperature. Viscosity (23 ° C.) 114 mPa · s, solid content 32.6% by weight, solution acid value 34.3 mg− A copolymer solution of KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 13,600 and a dispersity of 2.54.

Example 2
A 1 L flask equipped with a reflux condenser, a dropping funnel and a stirrer is flowed with a suitable amount of nitrogen to form a nitrogen atmosphere, and 150 parts by weight of 3-methoxy-1-butanol and 110 parts by weight of 3-methoxybutyl acetate are added and stirred. While heating to 70 ° C. Next, 60 parts by weight of methacrylic acid (MAA) and 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (included in the formula (2a) are contained in the flask. Compound) and 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] ( A solution prepared by dissolving 240 parts by weight of (E-DCPA) in 170 parts by weight of 3-methoxybutyl acetate was dropped over about 3 hours using a dropping pump. On the other hand, a solution obtained by dissolving 50 parts by weight of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) in 220 parts by weight of 3-methoxybutyl acetate was dropped over about 5 hours using another dropping pump. did. After completion of the dropping of the polymerization initiator, the temperature is maintained at the same temperature for about 3 hours, and then cooled to room temperature. The viscosity (23 ° C.) is 100 mPa · s, the solid content is 31.7% by weight, and the solution acid value is 36.6 mg− A copolymer solution of KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 14900 and a dispersity of 1.67.

Example 3
A 1-L flask equipped with a reflux condenser, a dropping funnel and a stirrer is used to flow an appropriate amount of nitrogen to form a nitrogen atmosphere, and 160 parts by weight of 3-methoxy-1-butanol and 110 parts by weight of 3-methoxybutyl acetate are added and stirred. While heating to 65 ° C. Next, in the flask, 50 parts by weight of methacrylic acid (MAA), 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (compound contained in the formula (2a)) ) And 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] (E -A solution obtained by dissolving 180 parts by weight of DCPA) and 70 parts by weight of styrene (ST) in 170 parts by weight of 3-methoxy-1-butanol was dropped over about 4 hours using a dropping pump. On the other hand, a solution prepared by dissolving 30 parts by weight of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) in 225 parts by weight of 3-methoxybutyl acetate was dropped over about 5 hours using another dropping pump. did. After completion of the dropping of the polymerization initiator, the temperature is maintained at the same temperature for about 4 hours, and then cooled to room temperature. Viscosity (23 ° C.) 50 mPa · s, solid content 31.6% by weight, solution acid value 34.3 mg− A copolymer solution of KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 7230 and a dispersity of 1.63.

Example 4
As monomers, 60 parts by weight of methacrylic acid (MAA), 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (compound contained in formula (2a)) and 3, 4-Epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] (E-DCPA) 90 The procedure of Example 1 was repeated, except that 90 parts by weight of 3,4-epoxycyclohexylmethyl methacrylate (E-CHM) and 60 parts by weight of N-cyclohexylmaleimide (CHMI) were used. ) A copolymer solution having 114 mPa · s, a solid content of 32.6% by weight, and a solution acid value of 34.3 mg-KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 14700 and a dispersity of 2.68.

Example 5
As monomers, 55 parts by weight of methacrylic acid (MAA), 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (compound contained in formula (2a)) and 3, 4-Epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] (E-DCPA) 45 Example 1 except for using parts by weight, 80 parts by weight of 3,4-epoxycyclohexylmethyl methacrylate (E-CHM), 70 parts by weight of N-cyclohexylmaleimide (CHMI), and 50 parts by weight of methyl methacrylate (MMA). Then, a copolymer solution having a viscosity (23 ° C.) of 110 mPa · s, a solid content of 32.2% by weight, and a solution acid value of 33.3 mg-KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 12,800 and a dispersity of 2.38.

Example 6
As monomers, 50 parts by weight of methacrylic acid (MAA), 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (compound contained in formula (2a)) and 3, 4-Epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] (E-DCPA) 150 The same operation as in Example 1 was carried out except that 50 parts by weight, 50 parts by weight of glycidyl methacrylate (GMA), and 50 parts by weight of methyl methacrylate (MMA) were used. Viscosity (23 ° C.) 105 mPa · s, solid content 31.5 A copolymer solution having a weight% and a solution acid value of 34.5 mg-KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 9450 and a dispersity of 2.29.

Example 7
As monomers, 50 parts by weight of methacrylic acid (MAA), 2- (3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yloxy) ethyl acrylate (included in formula (2a)) Compound) and 2- (3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yloxy) ethyl acrylate (compound contained in formula (2b)) [50:50 ( Mole ratio)] (E-DCPEA) 180 parts by weight and N-cyclohexylmaleimide (CHMI) 70 parts by weight were used in the same manner as in Example 1, and the viscosity (23 ° C.) 115 mPa · s, solid content A copolymer solution having 31.3% by weight and a solution acid value of 34.7 mg-KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 12500 and a dispersity of 2.30.

Example 8
As monomers, 50 parts by weight of methacrylic acid (MAA), 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (compound contained in formula (2a)) and 3, 4-Epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] (E-DCPA) 180 Example 1 except that 70 parts by weight and dicyclopentanyloxyethyl acrylate [= 2- (tricyclo [5.2.1.0 ^2,6 ] decyloxy) ethyl acrylate] (DCPEA) were used. Then, a copolymer solution having a viscosity (23 ° C.) of 118 mPa · s, a solid content of 32.3% by weight, and a solution acid value of 32.4 mg-KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 12900 and a dispersity of 2.29.

Example 9
A 1 L flask equipped with a reflux condenser, a dropping funnel and a stirrer is flowed with a suitable amount of nitrogen to form a nitrogen atmosphere, and 200 parts by weight of 3-methoxy-1-butanol and 105 parts by weight of 3-methoxybutyl acetate are added and stirred. While heating to 90 ° C. Next, in the flask, 55 parts by weight of methacrylic acid (MAA), 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (compound contained in formula (2a)) ) And 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] (E -DCPA) 105 parts by weight, (3-ethyl-3-oxetanyl) methyl methacrylate (OXMA) 40 parts by weight, and N-cyclohexylmaleimide (CHMI) 100 parts by weight in 3-methoxybutyl acetate 140 parts by weight It dropped over about 5 hours using the dripping pump. On the other hand, a solution prepared by dissolving 30 parts by weight of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) in 225 parts by weight of 3-methoxybutyl acetate was dropped over about 5 hours using another dropping pump. did. After completion of the dropping of the polymerization initiator, the temperature is maintained at the same temperature for about 4 hours, and then cooled to room temperature. The viscosity (23 ° C.) is 88 mPa · s, the solid content is 30.1% by weight, the solution acid value is 35.7 mg− A copolymer solution of KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 11900 and a dispersity of 2.08.

Example 10
As monomers, 50 parts by weight of methacrylic acid (MAA), 2- (3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yloxy) ethyl acrylate (included in formula (2a)) Compound) and 2- (3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yloxy) ethyl acrylate (compound contained in formula (2b)) [50:50 ( Molar ratio)] (E-DCPEA) 80 parts by weight, tetrahydrofurfuryl methacrylate (THFMA) 100 parts by weight, and N-cyclohexylmaleimide (CHMI) 70 parts by weight A copolymer solution having a viscosity (23 ° C.) of 93 mPa · s, a solid content of 31.3 wt%, and a solution acid value of 32.5 mg-KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 12530 and a dispersity of 2.51.

Example 11
A 1 L flask equipped with a reflux condenser, a dropping funnel and a stirrer is flowed with a suitable amount of nitrogen to form a nitrogen atmosphere, and 150 parts by weight of 3-methoxy-1-butanol and 110 parts by weight of 3-methoxybutyl acetate are added and stirred. While heating to 90 ° C. Next, in the flask, 60 parts by weight of methacrylic acid (MAA), 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (compound contained in the formula (2a)) ) And 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] (E -DCPA) A solution obtained by dissolving 160 parts by weight of (3-ethyl-3-oxetanyl) methyl methacrylate (OXMA) in 170 parts by weight of 3-methoxybutyl acetate was added dropwise over about 3 hours using a dropping pump. . On the other hand, a solution obtained by dissolving 50 parts by weight of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) in 220 parts by weight of 3-methoxybutyl acetate was dropped over about 5 hours using another dropping pump. did. After completion of the dropping of the polymerization initiator, the temperature is maintained at the same temperature for about 3 hours, and then cooled to room temperature. The viscosity (23 ° C.) is 98 mPa · s, the solid content is 31.5% by weight, the solution acid value is 36.3 mg− A copolymer solution of KOH / g was obtained. The resulting copolymer had a weight average molecular weight Mw of 8,700 and a dispersity of 2.06.

Comparative Example 1
As Example 1, except that 55 parts by weight of methacrylic acid (MAA), 175 parts by weight of 3,4-epoxycyclohexylmethyl methacrylate (E-CHM), and 70 parts by weight of N-cyclohexylmaleimide (CHMI) were used as monomers. Then, a copolymer solution having a viscosity (23 ° C.) of 125 mPa · s, a solid content of 32.3% by weight, and a solution acid value of 34.0 mg-KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 14700 and a dispersity of 2.47.

Comparative Example 2
As monomers, 60 parts by weight of methacrylic acid (MAA), 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (compound contained in formula (2a)) and 3, 4-Epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] (E-DCPA) 50 The same operation as in Example 1 was carried out except that 130 parts by weight, 130 parts by weight of 3,4-epoxycyclohexylmethyl methacrylate (E-CHM), and 60 parts by weight of N-cyclohexylmaleimide (CHMI) were used. ) A copolymer solution having 115 mPa · s, a solid content of 31.9% by weight, and a solution acid value of 35.8 mg-KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 11,800 and a dispersity of 2.15.

Comparative Example 3
As monomers, 50 parts by weight of methacrylic acid (MAA), 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decan-9-yl acrylate (compound contained in formula (2a)) and 3, 4-Epoxytricyclo [5.2.1.0 ^2,6 ] decan-8-yl acrylate (compound contained in formula (2b)) [50:50 (molar ratio)] (E-DCPA) 60 Example 1 except that parts by weight, 50 parts by weight of 3,4-epoxycyclohexylmethyl methacrylate (E-CHM), 70 parts by weight of N-cyclohexylmaleimide (CHMI), and 70 parts by weight of methyl methacrylate (MMA) were used. Then, a copolymer solution having a viscosity (23 ° C.) of 103 mPa · s, a solid content of 32.9% by weight, and a solution acid value of 34.3 mg-KOH / g was obtained. The produced copolymer had a weight average molecular weight Mw of 13700 and a dispersity of 2.49.

Evaluation Test The following evaluation tests were performed using the copolymer solutions obtained in the examples and comparative examples. The results are shown in Table 1. In the table, the numbers in the column of the monomer composition represent parts by weight, and “E-DCP (E) A / epoxy” is an epoxy group-containing polymerizable unsaturated compound in an amount of E-DCPA or E-DCPEA. The “epoxy / copolymer” represents the ratio (wt%) of the total amount of the epoxy group-containing polymerizable unsaturated compound to the total amount of monomers.

(1) Storage stability About each copolymer solution (solid content concentration of about 30% by weight) obtained in Examples and Comparative Examples, 80 parts by weight of the copolymer solution, a cationic polymerization initiator (trade name “ Sun Aid SI-150 "(manufactured by Sanshin Chemical Industry Co., Ltd.) 0.5 parts by weight and 40 parts by weight of propylene glycol monomethyl ether acetate are mixed and dissolved by stirring for 5 minutes in a mixer, then degassed under reduced pressure, and radiation sensitive resin A composition solution was prepared. When the viscosity (23 ° C.) of the obtained radiation-sensitive resin composition solution is measured, the viscosity (23 ° C.) after being stored at room temperature for one month is measured again, and the rate of increase in viscosity during that time is less than 30% , And the case of 30% or more was rated as x.

(2) Developability Each copolymer solution obtained in Examples and Comparative Examples was diluted to a solid content concentration of 3.6% by weight using the same solvent as the reaction solvent. This solution was applied to a substrate (SUS304, 0.5 × 80 × 80 mm, puffed, single-sided SPV, Japanese test panel, standard test plate) using a bar coater, and dried in an oven at 120 ° C. for 2 hours. The sample was immersed in an alkaline developer (tetramethylammonium hydroxide 2.35 wt% aqueous solution) stretched to a height of about 1 cm in a stainless steel bat, and the time until the resin layer was completely dissolved and removed was measured. . If the time until complete dissolution was 3 minutes or less, it was evaluated as ◯ if it was longer than 3 minutes and less than 10 minutes, and Δ if it was 10 minutes or more.

(3) Transparency A radiation-sensitive resin composition solution was prepared in the same manner as in the above (1) storage stability test. After filtering this solution with a 0.2 μm Teflon (registered trademark) filter, it was applied on a glass substrate 1737 (Corning Inc., 0.7 mm thickness × 150 mm diameter) with a spinner to a film thickness of 3 μm, The film was dried on a hot plate at 90 ° C. for 3 minutes, and the whole surface was exposed using a high-pressure mercury lamp. Next, the entire surface of the coating film was exposed using a super high pressure mercury lamp without passing through a positive mask pattern, and dried by heating at 120 ° C. for 30 minutes in a clean oven. The minimum transmittance | permeability of wavelength 400nm -800nm was measured for the obtained board | substrate with a cured film using UV spectrophotometer (brand name "U-3300", Hitachi Ltd. make). When the minimum transmittance was 95% or more, “◯”, when 85% or more and less than 95%, Δ, and when less than 85%, ×.

(4) Heat resistance A radiation-sensitive resin composition solution was prepared in the same manner as in the above (1) storage stability test. After filtering this solution with a 0.2 μm Teflon (registered trademark) filter, it was applied on a glass substrate 1737 (Corning Inc., 0.7 mm thickness × 150 mm diameter) with a spinner to a film thickness of 3 μm, The film was dried on a hot plate at 90 ° C. for 3 minutes, and the whole surface was exposed using a high-pressure mercury lamp. Next, the coating film was heat-cured at 200 ° C. for 30 minutes in a clean oven, and then heat-treated again at 230 ° C. for 1 hour to measure the film thickness. The change in film thickness after reheating treatment is calculated as the film thickness reduction rate with respect to the film thickness after heating and curing at 200 ° C. for 30 minutes, and when the film thickness reduction rate is less than 3%, Was marked with x.

  As is clear from the table, the copolymers obtained in the examples have superior storage stability and heat resistance while maintaining transparency and developability as compared with the copolymers obtained in the comparative examples. Show.

Claims (4)

(A) monomeric units containing an alkali-soluble group and (B) in addition to the monomer units of which corresponds to epoxy-containing polymerizable unsaturated compound (C) (c1) alkyl optionally styrene substituted with a group, (c2 ) The following formula (1)

[Wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms, R ² represents a primary or secondary alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, aryl A group, an aralkyl group, a cyclic ether-containing group having 4 or more members, or a — (R ³ —O) _m —R ⁴ group (wherein R ³ is a divalent hydrocarbon group having 1 to 12 carbon atoms, R ⁴ is A hydrogen atom or a hydrocarbon group, m represents an integer of 1 or more]
In the unsaturated carboxylic acid ester represented, and (c3) Ri Do from at least one monomer unit corresponding to the epoxy group-free polymerizable unsaturated compound selected from the group consisting of N- substituted maleimide, a number average molecular weight In which the proportion of the monomer units (B) is 40 to 90% by weight with respect to the total monomer units, and 30% by weight or more of the monomer units (B). The following formulas (2a) and (2b)

(In the formula, each R ⁵ represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms which may be substituted with a hydroxyl group, and A may include a single bond or a hetero atom, respectively. Valent hydrocarbon group)
A monomer unit corresponding to at least one compound selected from 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane ring-containing compounds represented by Coalescence.   The copolymer according to claim 1, wherein the proportion of the monomer unit (A) is 10 to 50% by weight based on the total monomer units.   The copolymer according to claim 1 or 2, which is a resin for a photoresist soluble in an alkaline aqueous solution. In addition to (a) a polymerizable unsaturated compound having an alkali-soluble group and (b) an epoxy group-containing polymerizable unsaturated compound , (c) (c1) styrene optionally substituted with an alkyl group, (c2) Formula (1)

[Wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms, R ² represents a primary or secondary alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, aryl Group, aralkyl group, 4-membered or higher cyclic ether-containing group or-(R ³ -O-) _m R ⁴ group (wherein R ³ is a divalent hydrocarbon group having 1 to 12 carbon atoms, R ⁴ is A hydrogen atom or a hydrocarbon group, m represents an integer of 1 or more]
And (c3) a monomer mixture consisting of at least one epoxy group-free polymerizable unsaturated compound selected from the group consisting of (c3) N-substituted maleimides, The proportion of the group-containing polymerizable unsaturated compound (b) is 40 to 90% by weight with respect to the total amount of monomers, and 30% by weight or more of the epoxy group-containing polymerizable unsaturated compound (b) Following formula (2a) and (2b)

(In the formula, each R ⁵ represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms which may be substituted with a hydroxyl group, and A may include a single bond or a hetero atom, respectively. Valent hydrocarbon group)
And a monomer mixture which is at least one compound selected from 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane ring-containing compounds represented by the formula: A method for producing a copolymer.