JP5636839B2 - Radiation-sensitive resin composition, interlayer insulating film, method for forming interlayer insulating film, and display element - Google Patents

Description

  The present invention relates to a radiation-sensitive resin composition, an interlayer insulating film, a method for forming an interlayer insulating film, and a display element.

  An electronic component such as a thin film transistor (TFT) type liquid crystal display element is generally provided with an interlayer insulating film for insulating between wirings arranged in layers. For example, a TFT-type liquid crystal display element is manufactured through a process of forming a transparent electrode film on an interlayer insulating film and further forming a liquid crystal alignment film thereon. Since such an interlayer insulating film is exposed to a high temperature condition in the transparent electrode film forming step and a resist stripping solution in the electrode pattern forming step, it needs to have sufficient resistance to these.

  Conventionally, a positive-type radiation-sensitive resin composition using a radiation-sensitive acid generator has been used as a material for forming an interlayer insulating film from the viewpoint of patterning performance (see JP 2001-354822 A). In recent years, application of negative radiation-sensitive resin compositions has been advanced from the viewpoint of high sensitivity and high transparency of the resulting interlayer insulating film (see Japanese Patent Application Laid-Open No. 2000-162769).

  On the other hand, from the viewpoint of cost reduction and process time reduction accompanying the widespread use of liquid crystal panels, reduction of radiation irradiation time (higher sensitivity), higher resolution, and the like in a photolithography process are desired. However, when higher sensitivity, higher resolution, etc. are pursued, there is an inconvenience that causes a decrease in adhesion to the substrate, transparency, and the like.

  Under such circumstances, development of a radiation-sensitive resin composition having excellent sensitivity and resolution, and an interlayer insulating film having little unevenness and excellent transparency, development adhesion, relative dielectric constant, and the like are desired.

JP 2001-354822 A JP 2000-162769 A

  The present invention has been made on the basis of the circumstances as described above, and the object thereof is a radiation-sensitive resin composition excellent in sensitivity and resolution, and less unevenness, transparency, development adhesion, and dielectric constant. It is to provide an interlayer insulating film excellent in the above.

The invention made to solve the above problems is
[A] copolymer,
[B] polymerizable unsaturated compound,
[C] a radiation sensitive polymerization initiator, and [D] an organic solvent,
[A] the copolymer is
(A1) a structural unit derived from at least one compound selected from the group consisting of (meth) acrylic acid and unsaturated carboxylic acid anhydride (hereinafter sometimes referred to as “(A1) structural unit”),
(A2) Group consisting of glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether and 3- (meth) acryloyloxymethyl-3-ethyloxetane A structural unit derived from at least one compound selected from the above (hereinafter sometimes referred to as “(A2) structural unit”),
(A3) Structural unit derived from at least one compound selected from the group consisting of styrene, α-methylstyrene, 4-methylstyrene, and 4-hydroxystyrene (hereinafter sometimes referred to as “(A3) structural unit”). ), And (A4) methyl acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate , A structural unit derived from at least one compound selected from the group consisting of isobutyl (meth) acrylate and tert-butyl (meth) acrylate (hereinafter sometimes referred to as “(A4) structural unit”)
Including
[A] The content ratio of the structural unit (A1) in the copolymer is 1 mol% or more and 40 mol% or less,
(A2) The content ratio of the structural unit is 1 mol% or more and 15 mol% or less,
(A3) A radiation-sensitive resin composition having a structural unit content of 1 mol% to 70 mol%, and (A4) a structural unit content of 1 mol% to 30 mol%.

  The composition contains [A] copolymer, [B] polymerizable unsaturated compound, [C] radiation sensitive polymerization initiator and [D] organic solvent as described above. [A] When the copolymer contains a specific amount of structural units (A1) to (A4) derived from a specific compound, the solubility of the [A] copolymer in an alkaline aqueous solution is optimized, resulting in resolution. Can be improved. In addition, development adhesion and resistance can be imparted to an interlayer insulating film formed from the composition. In addition, when the composition contains the [B] polymerizable unsaturated compound and the [C] radiation sensitive polymerization initiator, an interlayer insulating film having better sensitivity can be obtained even in the case of a low exposure amount.

  [A] The copolymer further contains (A5) a structural unit derived from at least one compound selected from the group consisting of maleimide, N-phenylmaleimide and N-cyclohexylmaleimide, It is preferable that a content rate is 1 mol% or more and 40 mol% or less.

  [D] The organic solvent preferably contains an organic solvent represented by the following formula (1). [D] The organic solvent is a solvent used for the preparation of the composition and uniformly dissolves the [A] copolymer, [B] polymerizable unsaturated compound and [C] radiation sensitive polymerization initiator. It is preferable to disperse, and for example, unevenness can be eliminated by including an organic solvent represented by the following formula (1).

（式（１）中、Ｒ^１及びＲ^２はそれぞれ独立して、炭素数１〜６のアルキル基である。ｎは１〜６の整数である。）

(In Formula (1), R ¹ and R ² are each independently an alkyl group having 1 to 6 carbon atoms. N is an integer of 1 to 6)

  [B] The polymerizable unsaturated compound includes a polymerizable unsaturated compound having a hydroxyl group or a carboxyl group, and the content of the [B] polymerizable unsaturated compound is from 10 mol% to 60 mol%. preferable. [B] Since the polymerizable unsaturated compound has a specific amount of hydroxyl group or carboxyl group, the interlayer insulation has higher resistance due to the curing reaction with the epoxy group derived from the (A2) compound of the [A] copolymer. A membrane is obtained.

The method for forming an interlayer insulating film of the present invention includes:
(1) The process of forming the coating film of the said composition on a board | substrate,
(2) A step of irradiating at least a part of the coating film with radiation,
(3) a step of developing the coating film irradiated with the radiation; and (4) a step of baking the developed coating film.

  According to the forming method of the present invention, it is possible to form an interlayer insulating film with less unevenness and residue after development, and excellent in transparency and relative dielectric constant. Therefore, the composition is suitable for forming an interlayer insulating film for a display element.

  The display element provided with the said interlayer insulation film is also suitably contained in this invention.

  Note that “firing” in the present specification means heating until the surface hardness required for the interlayer insulating film is obtained. The “radiation” of the “radiation sensitive resin composition” is a concept including visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams and the like.

  As described above, the present invention can provide a radiation-sensitive resin composition excellent in sensitivity and resolution, and an interlayer insulating film with less unevenness and excellent transparency, development adhesion, relative dielectric constant, and the like. Therefore, such an interlayer insulating film is suitably used for a display element.

<Radiation sensitive resin composition>
The radiation-sensitive resin composition of the present invention contains [A] a copolymer, [B] a polymerizable unsaturated compound, [C] a radiation-sensitive polymerization initiator and [D] an organic solvent, and further contains optional components. You may contain. Hereinafter, each component will be described in detail.

<[A] Copolymer>
[A] The copolymer is
(A1) a structural unit derived from at least one compound selected from the group consisting of (meth) acrylic acid and unsaturated carboxylic acid anhydride (hereinafter sometimes referred to as “(A1) compound”),
(A2) Glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4- (meth) acryloyloxybutyl glycidyl ether and 3-ethyl-3-methyl (meth) acrylate oxetane A structural unit derived from at least one selected compound (hereinafter sometimes referred to as “(A2) compound”),
(A3) A structural unit derived from at least one compound selected from the group consisting of styrene, α-methylstyrene, 4-methylstyrene and 4-hydroxystyrene (hereinafter sometimes referred to as “(A3) compound”). And (A4) methyl acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, 1-methylethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate , At least one compound selected from the group consisting of sec-butyl (meth) acrylate, isobutyl (meth) acrylate and tert-butyl (meth) acrylate (hereinafter sometimes referred to as “(A4) compound”). ), And the content ratio of the (A1) structural unit in the [A] copolymer is 1 mol% or more and 40 mol. % (A2) The structural unit content is 1 mol% or more and 15 mol% or less, (A3) The structural unit content is 1 mol% or more and 70 mol% or less, and (A4) the structural unit content is 1 mol% or less. It is mol% or more and 50 mol% or less.

[(A1) Compound]
The compound (A1) is at least one compound selected from the group consisting of (meth) acrylic acid and unsaturated carboxylic anhydride. (A1) As unsaturated carboxylic acid anhydride which is a compound, unsaturated dicarboxylic acid anhydride is mentioned typically. Examples of the unsaturated dicarboxylic anhydride include maleic anhydride, fumaric anhydride, citraconic anhydride, mesaconic anhydride, itaconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, cyclohexene-1,2-dicarboxylic acid Examples include acid anhydrides and 3-butene-1,2-dicarboxylic acid anhydrides.

  As the compound (A1), acrylic acid, methacrylic acid, and maleic anhydride are more preferable in view of copolymerization reactivity, solubility of the [A] copolymer in an alkaline aqueous solution, and availability. These (A1) compounds may be used alone or in admixture of two or more.

  [A] The copolymer contains 1 mol% or more and 40 mol% or less of a structural unit derived from the compound (A1). Preferably it contains 10 mol% or more and 35 mol% or less. (A1) By making the ratio of the structural unit of a compound 1 mol% or more and 40 mol% or less, the solubility with respect to the alkaline aqueous solution of [A] copolymer can be optimized, and resolution can be improved as a result. .

[(A2) Compound]
The (A2) compound is a radically polymerizable (meth) acrylate glycidyl, (meth) acrylate 3,4-epoxycyclohexylmethyl, 4- (meth) acryloyloxybutyl glycidyl ether and 3-ethyl-3-methyl ( It is at least one compound selected from the group consisting of (meth) acrylate oxetane. Since the epoxy group derived from these (A2) compounds and the carboxyl group or acid anhydride group derived from the (A1) compound undergo a crosslinking reaction, the curability of the composition can be improved. These (A2) compounds may be used alone or in combination of two or more.

  [A] The copolymer contains 1 mol% or more and 15 mol% or less of a structural unit derived from the compound (A2). (A2) By making the ratio of the structural unit of a compound 1 mol% or more and 15 mol% or less, the interlayer insulation film which can balance developability, resolution, and tolerance at a high level can be formed.

[(A3) Compound]
(A3) The compound is at least one compound selected from the group consisting of styrene, α-methylstyrene, 4-methylstyrene and 4-hydroxystyrene. [A] A copolymer contains 1 mol% or more and 70 mol% or less of structural units derived from the compound (A3). Preferably it contains 40 mol% or more and 65 mol% or less. (A3) By making the ratio of the structural unit of a compound 1 mol% or more and 70 mol% or less, the radiation sensitive resin composition which can form the interlayer insulation film excellent in image development adhesiveness and tolerance is obtained.

[(A4) Compound]
(A4) Compound is methyl acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate , At least one compound selected from the group consisting of isobutyl (meth) acrylate and tert-butyl (meth) acrylate. When (A4) methyl acrylate or an alkyl (meth) acrylate having 2 to 4 carbon atoms is used as the compound, it is excellent in developing adhesion at the time of forming the interlayer insulating film. On the other hand, when methyl methacrylate is used instead of the compound (A4), the Tg is high and the development adhesion of the formed interlayer insulating film may be inferior. [A] A copolymer contains 1 mol% or more and 30 mol% or less of structural units derived from the compound (A4). Preferably it contains 5 mol% or more and 25 mol% or less. (A4) By making the ratio of the structural unit of a compound 1 mol% or more and 30 mol% or less, the radiation sensitive resin composition excellent in the development adhesiveness and tolerance of the interlayer insulation film formed is obtained.

[(A5) Compound]
[A] The copolymer is selected from the group consisting of (A5) maleimide, N-phenylmaleimide and N-cyclohexylmaleimide as necessary in addition to the structural units derived from the above-mentioned compounds (A1) to (A4). It is preferable that a structural unit derived from at least one compound is further contained, and the content ratio of the structural unit (A5) is 1 mol% or more and 40 mol% or less. By further containing 1 mol% or more and 40 mol% or less of a structural unit derived from the compound (A5), the heat-resistant transparency can be further improved.

  [A] Examples of the method for synthesizing the copolymer include a method of radical copolymerizing the compounds (A1) to (A4) and, if necessary, the compound (A5) in the presence of a polymerization initiator in a solvent.

[A] The weight average molecular weight (Mw) of the copolymer is preferably 2 × 10 ³ to 1 × 10 ^{5, and} more preferably 5 × 10 ^{3 to} 5 × 10 ⁴ . [A] By setting the Mw of the copolymer to 2 × 10 ³ to 1 × 10 ⁵ , the radiation sensitivity and developability of the composition can be improved. In addition, Mw and number average molecular weight (Mn) of the polymer in this specification were measured by gel permeation chromatography (GPC) under the following conditions.
Apparatus: GPC-101 (Showa Denko)
Column: GPC-KF-801, GPC-KF-802, GPC-KF-803 and GPC-KF-804 combined with mobile phase: tetrahydrofuran Column temperature: 40 ° C.
Flow rate: 1.0 mL / min Sample concentration: 1.0 mass%
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

  [A] Solvents used in the polymerization reaction for producing the copolymer include, for example, alcohol, glycol ether, ethylene glycol alkyl ether acetate, diethylene glycol monoalkyl ether, diethylene glycol dialkyl ether, dipropylene glycol dialkyl ether, propylene glycol mono Examples include alkyl ether, propylene glycol alkyl ether acetate, propylene glycol monoalkyl ether propionate, ketone, ester and the like.

Examples of the alcohol include benzyl alcohol;
Examples of glycol ethers include ethylene glycol monomethyl ether and ethylene glycol monoethyl ether;
Examples of the ethylene glycol alkyl ether acetate include ethylene glycol monobutyl ether acetate and diethylene glycol monoethyl ether acetate;
Examples of the diethylene glycol monoalkyl ether include diethylene glycol monomethyl ether and diethylene glycol monoethyl ether;
Examples of the diethylene glycol dialkyl ether include diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether and the like;
Examples of the dipropylene glycol dialkyl ether include dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and dipropylene glycol ethyl methyl ether;
Examples of the propylene glycol monoalkyl ether include propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, and propylene glycol butyl ether;
Examples of the propylene glycol alkyl ether acetate include propylene glycol methyl ether acetate and propylene glycol ethyl ether acetate;
Examples of the propylene glycol monoalkyl ether propionate include propylene glycol methyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol propyl ether propionate and the like;
Examples of the ketone include methyl ethyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, and methyl isoamyl ketone;
Examples of the ester include ethyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, butyl hydroxyacetate, methyl lactate, ethyl lactate, Propyl lactate, butyl lactate, ethyl 2-ethoxypropionate, propyl 2-ethoxypropionate, butyl 2-ethoxypropionate, methyl 2-butoxypropionate, ethyl 2-butoxypropionate, propyl 2-butoxypropionate, 2- Butyl propionate butyl, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate 3-ethoxy propionate propyl, 3-ethoxy propionate butyl, 3-propoxy-propionic acid methyl, and the like.

  Of these solvents, ethylene glycol alkyl ether acetate, diethylene glycol monoalkyl ether, diethylene glycol dialkyl ether, propylene glycol monoalkyl ether, and propylene glycol alkyl ether acetate are preferred, and diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol. Monomethyl ether acetate is more preferred.

  [A] What is generally known as a radical polymerization initiator can be used as the polymerization initiator used in the polymerization reaction for producing the copolymer. Examples of the radical polymerization initiator include 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobis- (4- Azo compounds such as methoxy-2,4-dimethylvaleronitrile); organic peroxides such as benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1′-bis- (t-butylperoxy) cyclohexane and peroxides Examples include hydrogen oxide. When a peroxide is used as the radical polymerization initiator, the peroxide may be used together with a reducing agent to form a redox initiator.

  [A] In the polymerization reaction for producing the copolymer, a molecular weight modifier can be used to adjust the molecular weight. Examples of the molecular weight modifier include halogenated hydrocarbons such as chloroform and carbon tetrabromide; mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and thioglycolic acid; Xanthogens such as xanthogen sulfide and diisopropylxanthogen disulfide; terpinolene, α-methylstyrene dimer and the like.

<[B] polymerizable unsaturated compound>
Examples of the [B] polymerizable unsaturated compound contained in the composition include ω-carboxypolycaprolactone mono (meth) acrylate, ethylene glycol mono (meth) acrylate, ethylene glycol di (meth) acrylate, 1,6- Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, bisphenoxyethanol full orange ( (Meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, 2-hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate, 2- (2′-vinyloxyethoxy) ethyl (meth) ) Acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri (2- (Meth) acryloyloxyethyl) phosphate, ethylene oxide modified dipentaerythritol hexaacrylate, succinic acid modified pentaerythritol triacrylate, succinic acid modified dipentaerythritol pentaacrylate, etc., as well as linear alkylene groups and alicyclic structures And a compound having two or more isocyanate groups and a compound having one or more hydroxyl groups in the molecule and having 3 to 5 (meth) acryloyl groups. Urethane obtained by response (meth) acrylate compounds, and the like.

As a commercial item of the above-mentioned [B] polymerizable unsaturated compound, for example, Aronix M-400, M-402, M-405, M-450, M-1310, M-1600, M-1960 M-7100, M-8030, M-8060, M-8100, M-8100, M-8530, M-8560, M-9050, Aronix TO-1450, TO-1382 (above, Toagosei) Company);
KAYARAD DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-120, MAX-3510 (above, Nippon Kayaku Co., Ltd.);
Biscote 295, 300, 360, GPT, 3PA, 400 (Osaka Organic Chemical Co., Ltd.);
As a urethane acrylate compound, New Frontier R-1150 (Daiichi Kogyo Seiyaku Co., Ltd.);
KAYARAD DPHA-40H, UX-5000 (Nippon Kayaku Co., Ltd.);
UN-9000H (Negami Kogyo Co.);
Aronix M-5300, M-5600, M-5700, M-210, M-220, M-240, M-270, M-6200, M-305, M-309, M M-310, M-315 (above, Toagosei Co., Ltd.);
KAYARAD HDDA, KAYARAD HX-220, HX-620, R-526, R-167, R-604, R-684, R-551, R-712, UX-2201, UX-2301 UX-3204, UX-3301, UX-4101, UX-6101, UX-7101, UX-8101, UX-0937, MU-2100, MU-4001 (above, Nippon Kayaku Co., Ltd.);
Art Resin UN-9000PEP, UN-9200A, UN-7600, UN-333, UN-1003, UN-1255, UN-6060PTM, UN-6060P (Negami Industrial Co., Ltd.);
SH-500B biscoat 260, 312 and 335HP (above, Osaka Organic Chemical Industry Co., Ltd.). These can be used alone or in admixture of two or more.

  [B] The polymerizable unsaturated compound includes a polymerizable unsaturated compound having a hydroxyl group or a carboxyl group, and the content of the [B] polymerizable unsaturated compound is 10 mol% or more and 60 mol% or less. Is preferred. [B] Since the polymerizable unsaturated compound has a specific amount of hydroxyl group or carboxyl group, the interlayer insulation has higher resistance due to the curing reaction with the epoxy group derived from the (A2) compound of the [A] copolymer. A membrane is obtained. As a content rate of the [B] polymerizable unsaturated compound in the said composition, 20 mass parts-150 mass parts are preferable with respect to 100 mass parts of [A] copolymers, and 40 mass parts-100 mass parts are more. preferable. [B] By making the content rate of a polymerizable unsaturated compound into the said range, the said composition is excellent in image development adhesiveness, and the interlayer insulation film which has sufficient hardness also in the low exposure amount is obtained.

<[C] Radiation sensitive polymerization initiator>
The [C] radiation sensitive polymerization initiator contained in the composition is a component that generates an active species capable of initiating polymerization of the [B] polymerizable unsaturated compound in response to radiation. Examples of such [C] radiation-sensitive polymerization initiators include O-acyloxime compounds, acetophenone compounds, biimidazole compounds, and the like.

  Examples of the O-acyloxime compound include ethanone-1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime), 1- [9- Ethyl-6-benzoyl-9H-carbazol-3-yl] -octane-1-oneoxime-O-acetate, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]- Ethan-1-one oxime-O-benzoate, 1- [9-n-butyl-6- (2-ethylbenzoyl) -9H-carbazol-3-yl] -ethane-1-one oxime-O-benzoate, ethanone-1 -[9-ethyl-6- (2-methyl-4-tetrahydrofuranylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime) Ethanone-1- [9-ethyl-6- (2-methyl-4-tetrahydropyranylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime), ethanone-1- [9-ethyl -6- (2-Methyl-5-tetrahydrofuranylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime), ethanone-1- [9-ethyl-6- {2-methyl-4 -(2,2-dimethyl-1,3-dioxolanyl) methoxybenzoyl} -9H-carbazol-3-yl] -1- (O-acetyloxime) and the like. Of these, ethanone-1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime), ethanone-1- [9-ethyl-6 -(2-Methyl-4-tetrahydrofuranylmethoxybenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime) or ethanone-1- [9-ethyl-6- {2-methyl-4- (2,2-Dimethyl-1,3-dioxolanyl) methoxybenzoyl} -9H-carbazol-3-yl] -1- (O-acetyloxime) is preferred. These O-acyloxime compounds may be used alone or in combination of two or more.

  Examples of the acetophenone compound include an α-aminoketone compound and an α-hydroxyketone compound.

  Examples of the α-aminoketone compound include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-dimethylamino-2- (4-methylbenzyl) -1- ( 4-morpholin-4-yl-phenyl) -butan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, and the like.

  Examples of the α-hydroxyketone compound include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1- (4-i-propylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone and the like can be mentioned.

  Of these acetophenone compounds, α-aminoketone compounds are preferred, such as 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one or 2-dimethylamino-2- (4-methylbenzyl). ) -1- (4-Morpholin-4-yl-phenyl) -butan-1-one is more preferred.

  Examples of the biimidazole compound include 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetrakis (4-ethoxycarbonylphenyl) -1,2′-biimidazole, 2,2 ′. -Bis (2-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis (2,4-dichlorophenyl) -4,4', 5 5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (2,4,6-trichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-bi Examples include imidazole. Among these, 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (2,4-dichlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole or 2,2'-bis (2,4,6-trichlorophenyl) -4,4', 5,5'-tetra Phenyl-1,2'-biimidazole is preferred, and 2,2'-bis (2,4-dichlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole is more preferred.

  [C] Commercially available products may be used as the radiation-sensitive polymerization initiator, such as 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (Irgacure 907), 2 -(4-Methylbenzyl) -2- (dimethylamino) -1- (4-morpholinophenyl) -butan-1-one (Irgacure 379), ethanone-1- [9-ethyl-6- (2-methyl) Benzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime) (Irgacure OXE02), 1- [4- (phenylthio) -2- (O-benzoyloxime)] (Irgacure OXE01), bis ( 2,4,6 trimethylbenzoyl) -phenylphosphine oxide (Irgacure 819) (above, Ciba Specialty Chemicals) And the like.

  [C] The radiation-sensitive polymerization initiators can be used alone or in admixture of two or more. As a content rate of the [C] radiation sensitive polymerization initiator in the said composition, 1 mass part-25 mass parts are preferable with respect to 100 mass parts of [A] copolymers, and 1 mass part-20 mass parts are. More preferred. [C] By making the content rate of a radiation sensitive polymerization initiator into 1 mass part-25 mass parts, the said composition can form the interlayer insulation film which has high adhesiveness also in the case of a low exposure amount.

<[D] Organic solvent>
Solvents used for the preparation of the composition include [A] copolymer, [B] polymerizable unsaturated compound, [C] radiation sensitive polymerization initiator, [D] organic solvent and optional components uniformly dissolved. Or what is disperse | distributed and does not react with each component is used. As such a solvent, the thing similar to what was illustrated as a solvent which can be used in order to synthesize | combine the [A] copolymer mentioned above is mentioned. A solvent can be used individually or in mixture of 2 or more types.

  From the viewpoint of the solubility of each component, the reactivity with each component, the ease of coating film formation, and the like, the [D] organic solvent preferably contains the organic solvent represented by the above formula (1). [D] The organic solvent is a solvent used for the preparation of the composition and uniformly dissolves the [A] copolymer, [B] polymerizable unsaturated compound and [C] radiation sensitive polymerization initiator. It is preferable to disperse, and for example, unevenness can be eliminated by including the organic solvent represented by the above formula (1).

The formula (1), ^{R 1} and ^{R 2} are each independently an alkyl group having 1 to 6 carbon atoms. n is an integer of 1-6. The alkyl group having 1 to 6 carbon atoms may be either linear or branched, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. These [D] organic solvents represented by the formula (1) are more preferably methyl 3-methoxypropionate and ethyl 3-methoxypropionate.

<Optional component>
In addition to the above [A] copolymer, [B] polymerizable unsaturated compound, [C] radiation sensitive polymerization initiator, and [D] organic solvent, the composition does not impair the effects of the present invention. In [E], it can contain optional components such as an adhesion assistant, [F] surfactant, and [G] polymerization inhibitor. Each of these optional components may be used alone or in combination of two or more. Hereinafter, the optional components will be described in detail.

[[E] Adhesion aid]
[E] The adhesion assistant can be used to further improve the adhesion between the obtained interlayer insulating film and the substrate. Such [E] adhesion assistant is preferably a functional silane coupling agent having a reactive functional group such as a carboxyl group, a methacryloyl group, a vinyl group, an isocyanate group, or an oxiranyl group, such as trimethoxysilylbenzoic acid. , Γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyl Examples include trimethoxysilane and 2- (2-vinyloxyethoxy) ethyl acrylate.

  [E] The use amount of the adhesion assistant is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less with respect to 100 parts by mass of the [A] copolymer. When the amount of the adhesion aid used exceeds 15 parts by mass, there is a tendency that development residue tends to occur.

[[F] Surfactant]
[F] A surfactant can be used to further improve the film-forming property of the composition. Examples of the surfactant include a fluorine-based surfactant, a silicone-based surfactant, and other surfactants. The fluorine-based surfactant is preferably a compound having a fluoroalkyl group and / or a fluoroalkylene group in at least one of the terminal, main chain and side chain, for example, 1,1,2,2-tetrafluoro-n. -Octyl (1,1,2,2-tetrafluoro-n-propyl) ether, 1,1,2,2-tetrafluoro-n-octyl (n-hexyl) ether, hexaethylene glycol di (1,1,2, 2,3,3-hexafluoro-n-pentyl) ether, octaethylene glycol di (1,1,2,2-tetrafluoro-n-butyl) ether, hexapropylene glycol di (1,1,2,2,3, 3-hexafluoro-n-pentyl) ether, octapropylene glycol di (1,1,2,2-tetrafluoro-n-butyl) ether Sodium perfluoro-n-dodecanesulfonate, 1,1,2,2,3,3-hexafluoro-n-decane, 1,1,2,2,8,8,9,9,10,10-decafluoro-n -Dodecane, sodium fluoroalkylbenzenesulfonate, sodium fluoroalkylphosphate, sodium fluoroalkylcarboxylate, diglycerin tetrakis (fluoroalkylpolyoxyethylene ether), fluoroalkylammonium iodide, fluoroalkylbetaine, other fluoroalkylpolyoxy Examples thereof include ethylene ether, perfluoroalkyl polyoxyethanol, perfluoroalkyl alkoxylate, and carboxylic acid fluoroalkyl ester.

  Commercially available fluorosurfactants include, for example, BM-1000, BM-1100 (above, BM CHEMIE), MegaFuck F142D, F172, F173, F183, F178, F191, F191, and F471. F476 (above, Dainippon Ink & Chemicals, Inc.), Florard FC-170C, -171, -430, -431 (above, Sumitomo 3M), Surflon S-112, -113, -131, -141, -145, -382, Surflon SC-101, -102, -103, -104, -105, -106 (above, Asahi Glass), F-top EF301, 303, 352 (above, Shin-Akita Kasei Co., Ltd.), Footent FT-100, -110, -140A, -150, -250, and -25 , The -300, the -310, the -400S, Ftergent FTX-218, the same -251, Ftergent 710F (or, Neos Co., Ltd.).

  Examples of commercially available silicone surfactants include Torresilicone DC3PA, DC7PA, SH11PA, SH21PA, SH28PA, SH29PA, SH30PA, SH-190, SH-193, SZ-6032, SF-8428, DC-57, DC-190 (above, Toray Dow Corning Silicone), TSF-4440, TSF-4300, TSF-4445, TSF-4446, TSF-4460, TSF-4442 (above GE Toshiba Silicone), organosiloxane polymer KP341 (Shin-Etsu Chemical Co., Ltd.) and the like.

  Examples of other surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene-n-octylphenyl ether, polyoxyethylene-n- Polyoxyethylene aryl ethers such as nonylphenyl ether; nonionic surfactants such as polyoxyethylene dialkyl esters such as polyoxyethylene dilaurate and polyoxyethylene distearate; (meth) acrylic acid copolymer polyflow No. 57, no. 95 (above, Kyoeisha Chemical Co., Ltd.).

  As the usage-amount of surfactant, 1.0 mass part or less is preferable with respect to 100 mass parts of [A] copolymers, and 0.8 mass part or less is more preferable. When the usage-amount of surfactant exceeds 1.0 mass part, it will become easy to produce a film | membrane nonuniformity.

[[G] Polymerization inhibitor]
[G] Examples of the polymerization inhibitor include sulfur, quinones, hydroquinones, polyoxy compounds, amines, nitronitroso compounds, and more specifically, p-methoxyphenol, N-nitroso-N-phenylhydroxyl. Examples include amine aluminum.

  [G] The amount of the polymerization inhibitor used is preferably 3.0 parts by mass or less and more preferably 1.0 part by mass or less with respect to 100 parts by mass of the [A] copolymer. [G] When the usage-amount of a polymerization inhibitor exceeds 3.0 mass parts, the sensitivity of the said composition may fall and a pattern shape may deteriorate.

<Method for preparing the composition>
In addition to the [A] copolymer, the [B] polymerizable unsaturated compound, the [C] radiation sensitive polymerization initiator and the [D] organic solvent, the composition contains optional components at a predetermined ratio as necessary. Prepared by mixing. This radiation-sensitive resin composition is preferably used in a solution state after being dissolved in an appropriate solvent.

  When the composition is prepared as a solution, the solid content concentration (components other than the solvent in the composition solution) can be set to any concentration (for example, 5% by mass to 5% by mass depending on the purpose of use, the desired film thickness value, etc.). 50% by mass). A more preferable solid content concentration varies depending on the method of forming a film on the substrate, which will be described later. The composition solution thus prepared can be used after being filtered using a Millipore filter or the like having a pore size of about 0.5 μm.

<Interlayer insulating film and method for forming the same>
The composition is suitable for forming an interlayer insulating film for a display element.
(1) The process of forming the coating film of the said composition on a board | substrate,
(2) A step of irradiating at least a part of the coating film with radiation,
(3) a step of developing the coating film irradiated with the radiation; and (4) a step of baking the developed coating film.

  According to the forming method of the present invention, it is possible to form an interlayer insulating film with less unevenness and residue and excellent transparency and relative dielectric constant. Hereinafter, each process is explained in full detail.

[Step (1)]
In this step, a transparent conductive film is formed on one side of the transparent substrate, and a film of the composition is formed on the transparent conductive film. Examples of the transparent substrate include glass substrates such as soda lime glass and alkali-free glass, and resin substrates made of plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and polyimide.

As the transparent conductive film provided on one surface of the transparent substrate, a NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) Etc.

  In the case of forming a film by a coating method, the film can be formed by applying a solution of the composition on the transparent conductive film and then heating (pre-baking) the coated surface. As solid content concentration of the composition solution used for a coating method, 5 mass%-50 mass% are preferable, 10 mass%-40 mass% are more preferable, 15 mass%-35 mass% are especially preferable. As a coating method of the composition, for example, an appropriate method such as a spray method, a roll coating method, a spin coating method (spin coating method), a slit coating method (slit die coating method), a bar coating method, an ink jet coating method or the like is adopted. it can. Of these, spin coating or slit coating is preferred.

  The prebaking conditions vary depending on the type of each component, the blending ratio, and the like, but are preferably 70 ° C. to 120 ° C. and about 1 to 15 minutes. The film thickness after pre-baking of the coating is preferably 0.5 μm to 10 μm, more preferably about 1.0 μm to 7.0 μm.

[Step (2)]
In this step, radiation is applied to at least a part of the formed film. At this time, when irradiating only a part of the film, for example, the irradiation can be performed through a photomask having a predetermined pattern.

  Examples of radiation used for irradiation include visible light, ultraviolet light, and far ultraviolet light. Of these, radiation having a wavelength in the range of 250 nm to 550 nm is preferable, and radiation including ultraviolet light of 365 nm is more preferable.

Radiation dose (exposure dose), as a value measured by a luminometer intensity at a wavelength 365nm of the radiation emitted (OAI model 356, Optical Associates Ltd. ^{Inc.), 100J / m 2 ~5,000J} / m 2 is Preferably, 200 J / m ^{2 to} 3,000 J / m ² is more preferable.

The composition has high radiation sensitivity compared to a conventionally known composition, and even when the radiation dose is 850 J / m ² or less, a desired film thickness, good shape, excellent adhesion and high An interlayer insulating film having a hardness can be obtained.

[Step (3)]
In this step, the film after irradiation is developed to remove unnecessary portions and form a predetermined pattern. Examples of the developer used for development include aqueous solutions of alkaline compounds such as inorganic alkalis such as sodium hydroxide, potassium hydroxide and sodium carbonate, and quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. It is done. An appropriate amount of a water-soluble organic solvent such as methanol or ethanol and / or a surfactant may be added to the aqueous solution of the alkaline compound.

  The developing method may be any of a liquid filling method, a dipping method, a shower method, and the like, and the developing time is preferably about 10 seconds to 180 seconds at room temperature. Subsequent to the development processing, for example, washing with running water is performed for 30 seconds to 90 seconds, and then a desired pattern is obtained by air drying with compressed air or compressed nitrogen.

[Step (4)]
In this step, the obtained interlayer film is baked (post-baked) with a suitable heating device such as a hot plate or oven to obtain an interlayer insulating film. As baking temperature, 100 to 250 degreeC is preferable and 150 to 230 degreeC is more preferable. The firing time is preferably, for example, 5 minutes to 30 minutes on a hot plate and 30 minutes to 180 minutes in an oven. Since the composition contains the organic solvent [D] as described above, it can be realized as a material for forming an interlayer insulating film used in a flexible display or the like that can achieve such low-temperature firing and is desired to be fired at low temperature.

<Display element and manufacturing method thereof>
The display element provided with the said interlayer insulation film is also suitably contained in this invention. The display element of the present invention can be produced, for example, by the following method.

  First, a pair (two) of transparent substrates having a transparent conductive film (electrode) on one side is prepared, and an interlayer insulating film is formed on the transparent conductive film of one of the substrates using the composition according to the method described above. In addition, a spacer, a protective film or the like is formed as necessary. Subsequently, an alignment film having liquid crystal alignment ability is formed and superimposed. These substrates are arranged facing each other with a certain gap (cell gap) so that the liquid crystal alignment direction of each alignment film is orthogonal or antiparallel, with the surface on which the alignment film is formed inside. A liquid crystal is filled in the cell gap defined by the surface of the substrate (alignment film) and the spacer, and the filling hole is sealed to constitute a liquid crystal cell. Then, the display element of the present invention is bonded to both outer surfaces of the liquid crystal cell such that the polarizing direction is aligned or orthogonal to the liquid crystal alignment direction of the alignment film formed on one surface of the substrate. can get.

  As another method, a pair of transparent substrates on which a transparent conductive film, an interlayer insulating film and the like and an alignment film are formed are prepared in the same manner as the above method. After that, along the edge of one substrate, an ultraviolet curable sealant is applied using a dispenser, and then the liquid crystal is dropped in the form of fine droplets using a liquid crystal dispenser, and the two substrates are bonded together under vacuum. . Then, both the substrates are sealed by irradiating the sealing agent part with ultraviolet rays using a high-pressure mercury lamp. Finally, the display element of the present invention is obtained by attaching polarizing plates to both outer surfaces of the liquid crystal cell.

  Examples of the liquid crystal used in each of the above methods include nematic liquid crystal and smectic liquid crystal. In addition, as a polarizing plate used outside the liquid crystal cell, a polarizing film in which a polarizing film called an “H film” that absorbs iodine while stretching and aligning polyvinyl alcohol is sandwiched between cellulose acetate protective films, or an H film Examples thereof include a polarizing plate made of itself.

  EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not interpreted limitedly to this Example.

<Synthesis of [A] copolymer>
[Synthesis Example 1]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 20 parts by mass of methacrylic acid, (A2) 10 parts by mass of glycidyl methacrylate, (A3) 60 parts by mass of styrene, (A4) 10 parts by mass of ethyl methacrylate and 1 part by mass of α-methylstyrene dimer were charged. After purging with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (A-1) (solid content concentration = 34.4% by mass, Mw = 10, 000, Mw / Mn = 2.4). As a result of ¹³ C-NMR analysis, the contents of (A1) structural unit, (A2) structural unit, (A3) structural unit, and (A4) structural unit were 23 mol%, 7 mol%, 60 mol%, and 10 mol, respectively. %Met. The content was determined by ¹ H-NMR, ¹³ C-NMR, FT-IR, and pyrolysis gas chromatography mass spectrometry.

[Synthesis Example 2]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 20 parts by mass of methacrylic acid, (A2) 10 parts by mass of glycidyl methacrylate, (A3) 50 parts by mass of styrene, (A4) 20 parts by mass of ethyl methacrylate and 1 part by mass of α-methylstyrene dimer were charged. After purging with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (A-2) (solid content concentration = 34.3 mass%, Mw = 10, 000, Mw / Mn = 2.3). As a result of analysis in the same manner as in Synthesis Example 1, the contents of (A1) structural unit, (A2) structural unit, (A3) structural unit, and (A4) structural unit were 24 mol%, 7 mol%, 50 mol%, respectively. It was 19 mol%.

[Synthesis Example 3]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 30 parts by mass of methacrylic acid, (A2) 10 parts by mass of glycidyl methacrylate, (A3) 50 parts by mass of styrene, (A4) 10 parts by mass of ethyl methacrylate and 1 part by mass of α-methylstyrene dimer were charged. After purging with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (A-3) (solid content concentration = 33.3% by mass, Mw = 11, 000, Mw / Mn = 2.4). As a result of analysis in the same manner as in Synthesis Example 1, the contents of (A1) structural unit, (A2) structural unit, (A3) structural unit, and (A4) structural unit were 35 mol%, 7 mol%, 50 mol%, respectively. It was 8 mol%.

[Synthesis Example 4]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 25 parts by mass of methacrylic acid, (A2) 5 parts by mass of glycidyl methacrylate, (A3) 50 parts by mass of styrene, (A4) 20 parts by mass of ethyl acrylate and 1 part by mass of α-methylstyrene dimer were charged. After purging with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (A-4) (solid content concentration = 34.0% by mass, Mw = 9, 000, Mw / Mn = 2.3). As a result of analysis in the same manner as in Synthesis Example 1, the contents of (A1) structural unit, (A2) structural unit, (A3) structural unit, and (A4) structural unit were 28 mol%, 4 mol%, 48 mol%, It was 20 mol%.

[Synthesis Example 5]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 25 parts by mass of methacrylic acid, (A2) 5 parts by mass of glycidyl methacrylate, (A3) 50 parts by mass of styrene, (A4) 20 parts by mass of isopropyl methacrylate and 1 part by mass of α-methylstyrene dimer were charged. After purging with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (A-5) (solid content concentration = 34.0% by mass, Mw = 9, 000, Mw / Mn = 2.3). As a result of analysis in the same manner as in Synthesis Example 1, the contents of (A1) structural unit, (A2) structural unit, (A3) structural unit, and (A4) structural unit were 30 mol%, 4 mol%, and 51 mol%, respectively. It was 16 mol%.

[Synthesis Example 6]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 20 parts by mass of methacrylic acid, (A2) 10 parts by mass of 3-ethyl-3-methyl methacrylate oxetane, (A3) 50 parts by mass of styrene, (A4) 20 parts by mass of ethyl methacrylate and α-methylstyrene. After 1 part by weight of dimer was charged and purged with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (A-6) (solid content concentration = 32.3 mass%, Mw = 9, 000, Mw / Mn = 2.3). As a result of analysis in the same manner as in Synthesis Example 1, the contents of (A1) structural unit, (A2) structural unit, (A3) structural unit, and (A4) structural unit were 25 mol%, 6 mol%, 50 mol%, It was 19 mol%.

[Synthesis Example 7]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 18 parts by mass of acrylic acid, (A2) 12 parts by mass of 3,4-epoxycyclohexylmethyl methacrylate, (A3) 50 parts by mass of styrene, (A4) 20 parts by mass of ethyl methacrylate and α-methylstyrene dimer. After 1 part by mass was charged and replaced with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (A-7) (solid content concentration = 32.3 mass%, Mw = 8, 000, Mw / Mn = 2.3). As a result of analysis in the same manner as in Synthesis Example 1, the contents of (A1) structural unit, (A2) structural unit, (A3) structural unit, and (A4) structural unit were 29 mol%, 9 mol%, 38 mol%, It was 24 mol%.

[Synthesis Example 8]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 20 parts by mass of methacrylic acid, (A2) 10 parts by mass of glycidyl methacrylate, (A3) 30 parts by mass of styrene, (A4) 20 parts by mass of ethyl methacrylate, (A5) 20 parts by mass of N-phenylmaleimide and After 1 part by mass of α-methylstyrene dimer was charged and purged with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (A-8) (solid content concentration = 34.0% by mass, Mw = 9, 000, Mw / Mn = 2.1). As a result of analysis in the same manner as in Synthesis Example 1, the contents of (A1) structural unit, (A2) structural unit, (A3) structural unit, (A4) structural unit, and (A5) structural unit were 26 mol% and 8 mol, respectively. %, 33 mol%, 20 mol%, and 13 mol%.

[Synthesis Example 9]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 30 parts by weight of methacrylic acid, (A2) 10 parts by weight of glycidyl methacrylate, (A3) 40 parts by weight of styrene, (A4) 10 parts by weight of ethyl methacrylate, 10 parts by weight of methyl methacrylate as other components, and After 1 part by mass of α-methylstyrene dimer was charged and purged with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (A-9) (solid content concentration = 33.3% by mass, Mw = 12, 000, Mw / Mn = 2.5). As a result of analysis in the same manner as in Synthesis Example 1, the content of (A1) structural unit, (A2) structural unit, (A3) structural unit, (A4) structural unit, and structural unit derived from methyl methacrylate was 35 mol each. %, 7 mol%, 39 mol%, 9 mol%, and 10 mol%.

[Comparative Synthesis Example 1]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of propylene glycol monomethyl ether acetate. Subsequently, (A1) 30 parts by mass of methacrylic acid, (A3) 60 parts by mass of styrene, (A4) 10 parts by mass of ethyl methacrylate and 1 part by mass of α-methylstyrene dimer were charged with nitrogen, and then gently stirred. It was. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (CA-1) (solid content concentration = 34.5% by mass, Mw = 9, 000, Mw / Mn = 2.3). As a result of analysis in the same manner as in Synthesis Example 1, the contents of (A1) structural unit, (A3) structural unit, and (A4) structural unit were 34 mol%, 57 mol%, and 9 mol%, respectively.

[Comparative Synthesis Example 2]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 25 parts by mass of methacrylic acid, (A2) 5 parts by mass of glycidyl methacrylate, (A3) 50 parts by mass of styrene, 20 parts by mass of methyl methacrylate, and 1 part by mass of α-methylstyrene dimer were charged and replaced with nitrogen. After that, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (CA-2) (solid content concentration = 35.4 mass%, Mw = 15, 000, Mw / Mn = 2.4). As a result of analysis in the same manner as in Synthesis Example 1, the contents of (A1) structural unit, (A2) structural unit, (A3) structural unit, and structural unit derived from methyl methacrylate were 30 mol%, 4 mol%, They were 49 mol% and 17 mol%.

[Comparative Synthesis Example 3]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of propylene glycol monomethyl ether acetate. Subsequently, (A1) 45 parts by weight of methacrylic acid, (A2) 5 parts by weight of glycidyl methacrylate, (A3) 40 parts by weight of styrene, (A4) 10 parts by weight of ethyl methacrylate and 1 part by weight of α-methylstyrene dimer were charged. After purging with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing a copolymer (CA-3) (solid content concentration = 34.4% by mass, Mw = 20, 000, Mw / Mn = 2.6). As a result of analysis in the same manner as in Synthesis Example 1, the contents of (A1) structural unit, (A2) structural unit, (A3) structural unit, and (A4) structural unit derived from the structural unit were 51 mol% and 3 mol, respectively. %, 37 mol%, and 9 mol%.

[Comparative Synthesis Example 4]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of diethylene glycol methyl ethyl ether. Subsequently, (A1) 12 parts by mass of methacrylic acid, (A2) 5 parts by mass of glycidyl methacrylate, (A3) 78 parts by mass of styrene, (A4) 5 parts by mass of ethyl methacrylate and 1 part by mass of α-methylstyrene dimer were charged. After purging with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer (CA-4) (solid content concentration = 35.0 mass%, Mw = 9, 000, Mw / Mn = 2.1). As a result of analysis in the same manner as in Synthesis Example 1, the content of (A1) structural unit, (A2) structural unit, (A3) structural unit, and (A4) structural unit derived from the structural unit was 14 mol% and 4 mol, respectively. %, 77 mol%, and 5 mol%.

[Comparative Synthesis Example 5]
A flask equipped with a condenser and a stirrer was charged with 7 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) and 200 parts by mass of methyl 3-methoxypropionate. Subsequently, (A1) 20 parts by mass of methacrylic acid, (A2) 5 parts by mass of glycidyl methacrylate, (A3) 30 parts by mass of styrene, (A4) 45 parts by mass of ethyl methacrylate and 1 part by mass of α-methylstyrene dimer were charged. After purging with nitrogen, stirring was started gently. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing a copolymer (CA-5) (solid content concentration = 35.1% by mass, Mw = 17, 000, Mw / Mn = 2.2). As a result of analysis in the same manner as in Synthesis Example 1, the content of (A1) structural unit, (A2) structural unit, (A3) structural unit, and (A4) structural unit derived from the structural unit was 24 mol% and 4 mol, respectively. %, 30 mol%, and 42 mol%.

<Preparation of radiation-sensitive resin composition>
[Example 1]
[A] In a solution containing (A-1) as a copolymer, (A-1) with respect to an amount corresponding to 100 parts by mass (solid content), [B] B-1) 25 parts by mass, (B-8) 25 parts by mass, [C] 5 parts by mass as a radiation-sensitive polymerization initiator, and [E] adhesion assistant as an optional component (E- 1) 1 part by mass and (E-2) 1 part by mass, [F] surfactant (F-1) 0.10 part by mass and [G] polymerization inhibitor (G-1) p-methoxyphenol 0.1 After mixing parts by mass and dissolving in methyl-3-methoxypropionate as an organic solvent [D] so that the solid content concentration is 30% by mass, it is filtered through a membrane filter having a pore size of 0.2 μm, A radiation sensitive resin composition (S-1) was prepared.

[Examples 2 to 23 and Comparative Examples 1 to 6]
Example 1 except that the types and amounts of [A] copolymer, [B] polymerizable unsaturated compound, [C] radiation sensitive polymerization initiator, [D] organic solvent and optional components shown in Table 1 were used. In the same manner as described above, radiation-sensitive resin compositions (S-2) to (S-23) and (CS-1) to (CS-6) were prepared.

  The detail of each component used by the Example and the comparative example is shown.

<[B] polymerizable unsaturated compound>
(B-1) to (B-5) Polymerizable unsaturated compound B-1 having hydroxyl group or carboxyl group: Succinic acid-modified pentaerythritol triacrylate (Toagosei Co., Aronix TO-756)
B-2: Succinic acid-modified dipentaerythritol pentaacrylate (Toagosei Co., Aronix M-520)
B-3: ω-carboxy-polycaprolactone monoacrylate B-4: a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (pentaerythritol triacrylate content of about 60%) (Shin Nakamura Chemical Co., Ltd., NK Ester A- TMM-3LM-N)
B-5: Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (dipentaerythritol pentaacrylate content 50%) (Shin Nakamura Chemical Co., Ltd., NK ester A-9550)
(B-6) to (B-9) Polymerizable unsaturated compound B-6 having neither hydroxyl group nor carboxyl group: Trimethylolpropane triacrylate (Shin Nakamura Chemical Co., Ltd., NK Ester A-TMPT)
B-7: Pentaerythritol tetraacrylate (Shin Nakamura Chemical Co., Ltd., NK Ester A-TMMT)
B-8: Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (dipentaerythritol hexaacrylate content 90%) (Shin Nakamura Chemical Co., Ltd., NK ester A-DPH)
B-9: A polymerizable unsaturated monomer containing a polyfunctional urethane acrylate compound (Nippon Kayaku Co., Ltd., KAYARAD DPHA-40H)

<[C] Radiation sensitive polymerization initiator>
C-1: Ethanone-1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime) (Ciba Specialty Chemicals, Irgacure OXE02 )
C-2: 1- [4- (phenylthio) -2- (O-benzoyloxime)] (Ciba Specialty Chemicals, Irgacure OXE01)
C-3: Bis (2,4,6 trimethylbenzoyl) -phenylphosphine oxide (Ciba Specialty Chemicals, Irgacure 819)
C-4: 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (Ciba Specialty Chemicals, Irgacure 907)

<[D] Organic solvent>
D-1: Methyl 3-methoxypropionate D-2: Ethyl 3-methoxypropionate D-3: Propylene glycol monomethoxyacetate D-4: Diethylene glycol methyl ethyl ether

<[E] Adhesion aid>
E-1: γ-Glycidoxypropyltrimethoxysilane (Chisso Corporation, S-510)
E-2: 2- (2-vinyloxyethoxy) ethyl acrylate (Nippon Shokubai, VEEA)

<[F] Surfactant>
F-1: Silicone surfactant (Toray Dow Corning Silicone, SH28PA)
F-2: Fluorine-based surfactant (Neos, Footage 710F)

<[G] Polymerization inhibitor>
G-1: p-methoxyphenol (Wako Pure Chemical Industries, p-methoxyphenol)

<Evaluation of physical properties of interlayer insulation film>
An interlayer insulating film was formed from the radiation-sensitive resin composition prepared as described above, and the physical properties were evaluated. The results are shown in Table 1.

[sensitivity]
After applying the radiation sensitive resin compositions (S-1) to (S-20) and (CS-1) to (CS-3) on a silicon substrate using a spinner, hot at 100 ° C. for 2 minutes. Pre-baked on the plate to form a coating film having a thickness of 4.0 μm. Next, using a light exposure machine (extra-high pressure mercury lamp, Canon Inc., PLA-501F), the coating film was exposed through a pattern mask having a predetermined pattern while changing the exposure time. Next, a development process was performed at 25 ° C. by a liquid piling method using a tetramethylammonium hydroxide aqueous solution (developer) having a concentration of 0.4% by mass. The development processing time was 100 seconds. After the development treatment, the coating film was washed with running ultrapure water for 1 minute and dried to form a pattern on the wafer. This silicon substrate was heated in a clean oven at 220 ° C. for 1 hour to obtain an interlayer insulating film. The film thickness of the obtained cured film was measured using a stylus type film thickness meter.
The exposure amount at which the remaining film ratio represented by the following formula (ratio in which the patterned thin film remains properly) is 85% or more is obtained as sensitivity, and when the sensitivity is less than 800 J / m ² , A, 800 J / m ² or more, 1, B in the case of less than ^{000J / m 2, 1,000J / m} 2 or more ~1,200J / ^{m 2} less than the case C, 1,200J / ^{m 2} or more when set to D.

[Resolution]
The minimum diameter of the through-hole formed in the interlayer insulating film formed as described above is observed with an optical microscope, and when the minimum diameter is 5 to 10 μm, A, when the minimum diameter is 10 to 20 μm, B and 20 μm The above case was designated as C, and the case where no hole was formed was designated as D.

[Residue]
A 10 × 10 μm hole in the interlayer insulating film formed as described above was observed with an optical microscope, and the degree of residue was evaluated. The case where the residue could not be confirmed was designated as A, the case where the residue could be confirmed slightly, B, the case where the residue could be confirmed clearly, C, and the case where the residue could be confirmed in large quantities as D.

[village]
The appearance of the interlayer insulating film formed as described above was visually observed. The case where unevenness could not be confirmed was indicated as A, the case where slight unevenness was confirmed as B, the case where much unevenness was confirmed as C, and the case where unevenness could be confirmed over the entire surface as D.

[transparency]
In the formation of the interlayer insulating film, an interlayer insulating film was formed on the glass substrate in the same manner except that a glass substrate (Corning 7059, Corning) was used instead of the silicon substrate. Using a spectrophotometer (150-20 type double beam, Hitachi, Ltd.), the light transmittance (%) of the glass substrate having the interlayer insulating film was measured at a wavelength in the range of 400 to 800 nm. The case where the minimum light transmittance exceeded 95% was A, the case where it was 90% or more and 95% or less was B, the case where it was less than 90% and 85% or more was C, and the case where it was less than 85% was D.

[Heat resistant transparency]
The substrate prepared by the above-described transparency evaluation was further heated at 250 ° C. for 1 hour in a clean oven, and the light transmittance before and after heating was measured in the same manner as in the above-described transparency evaluation. Heat resistance transparency (%) is calculated according to the following formula. When this value is 4% or less, it can be judged that the heat resistance transparency of the protective film is good.
Heat-resistant transparency (%) = light transmittance before heating (%) − light transmittance after heating (%)

[Development adhesion]
In the same manner as the formation of the interlayer insulating film, a coating film is formed, exposed at 2,000 J / m ² , and in the pattern of L / S = 1: 1, the minimum size remaining without being peeled after development is optical. Observed with a microscope. A minimum size of less than 30 μm was A, 30 μm or more and less than 50 μm was B, 50 μm or more was C, and D was a peeled piece.

[Relative permittivity]
After applying the radiation sensitive resin compositions (S-1) to (S-20) and (CS-1) to (CS-3) on a polished SUS304 substrate using a spinner, at 100 ° C. Prebaked on a hot plate for 2 minutes to form a coating film having a thickness of 3.0 μm. Next, using an exposure machine (extra-high pressure mercury lamp, Canon Inc., PLA-501F), the coating film is exposed so that the integrated irradiation amount is 3,000 J / m ^2, and this silicon substrate is placed in a clean oven. Was heated at 220 ° C. for 1 hour to form an interlayer insulating film having a thickness of 3.0 μm. A Pt / Pd electrode pattern for this interlayer insulating film was prepared by a vapor deposition method, and used as a sample for measuring relative permittivity. The relative dielectric constant of the substrate was measured by the CV method at a frequency of 10 kHz using an electrode (Yokogawa Hewlett-Packard Company, HP16451B) and an HP4284A Precision LCR meter. A sample having a relative dielectric constant of less than 3.5 was designated as A, a sample having a relative dielectric constant of 3.5 or more and less than 3.8 was designated as B, a sample having a relative dielectric constant of 3.8 or more and less than 4.1 was designated as C, and a sample having 4.1

  As is apparent from Table 1, the composition of the present invention was found to have good sensitivity and resolution. Further, it was found that the interlayer insulating film formed from the composition has little residue and unevenness, and is excellent in transparency, heat-resistant transparency, development adhesion, and relative dielectric constant.

  The present invention can provide a radiation-sensitive resin composition excellent in sensitivity and resolution, and an interlayer insulating film with less unevenness and excellent transparency, development adhesion, relative dielectric constant, and the like. Therefore, such an interlayer insulating film is suitably used for a display element.

Claims (7)

[A] copolymer,
[B] polymerizable unsaturated compound,
[C] a radiation sensitive polymerization initiator, and [D] an organic solvent,
[A] the copolymer is
(A1) a structural unit derived from at least one compound selected from the group consisting of (meth) acrylic acid and unsaturated carboxylic acid anhydride,
(A2) Group consisting of glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether and 3- (meth) acryloyloxymethyl-3-ethyloxetane A structural unit derived from at least one compound selected from
(A3) Structural units derived from at least one compound selected from the group consisting of styrene, α-methylstyrene, 4-methylstyrene and 4-hydroxystyrene, and (A4) methyl acrylate, ethyl (meth) acrylate At least one selected from the group consisting of n-propyl (meth) acrylate, isopropyl ( meth) acrylate, sec-butyl (meth) acrylate, isobutyl (meth) acrylate and tert-butyl (meth) acrylate. Including structural units derived from one compound,
[A] The content ratio of the structural unit (A1) in the copolymer is 1 mol% or more and 40 mol% or less,
(A2) The content ratio of the structural unit is 1 mol% or more and 15 mol% or less,
(A3) Radiation-sensitive resin for forming an interlayer insulating film of a display element having a structural unit content of 1 mol% to 70 mol%, and (A4) a structural unit content of 1 mol% to 30 mol% Composition. [A] the copolymer further comprises (A5) a structural unit derived from at least one compound selected from the group consisting of maleimide, N-phenylmaleimide and N-cyclohexylmaleimide;
The radiation sensitive resin composition according to claim 1, wherein the content ratio of the (A5) structural unit is 1 mol% or more and 40 mol% or less. [D] The radiation sensitive resin composition of Claim 1 or Claim 2 in which an organic solvent contains the organic solvent shown by following formula (1).

(In Formula (1), R ¹ and R ² are each independently an alkyl group having 1 to 6 carbon atoms. N is an integer of 1 to 6)   [B] The polymerizable unsaturated compound contains a polymerizable unsaturated compound having a hydroxyl group or a carboxyl group, and the content of the [B] polymerizable unsaturated compound is 10 mol% or more and 60 mol% or less. The radiation sensitive resin composition of Claim 1, Claim 2 or Claim 3.   The interlayer insulation film for display elements formed from the radiation sensitive resin composition of any one of Claims 1-4. (1) The process of forming the coating film of the radiation sensitive resin composition of any one of Claims 1-4 on a board | substrate,
(2) A step of irradiating at least a part of the coating film with radiation,
(3) A step of developing the coating film irradiated with the radiation, and (4) A method for forming an interlayer insulating film for a display element, comprising a step of baking the developed coating film.   A display element provided with the interlayer insulation film for display elements of Claim 5.