JP2017173526A - Photosensitive resin composition for insulating film, insulating film, and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition for an insulating film, capable of forming an insulating film which does not require a high-temperature heat treatment, is excellent in developability, and exhibits a sufficiently low dielectric constant.SOLUTION: The photosensitive resin composition for an insulating film contains (A) an alkali-soluble resin, (B) a photocurable monomer, (C) a photopolymerization initiator, and (D) a solvent. The alkali-soluble resin (A) contains a resin (a) having a repeating unit derived from (meth)acrylic acid. The photocurable monomer (B) contains a compound having two or three (meth)acryloyloxy groups linked by an aliphatic group which may be interrupted by an oxygen atom. In the photosensitive resin composition, a mass ratio of the alkali-soluble resin (A) to the photocurable monomer (B) is 1.2 or more.SELECTED DRAWING: None

Description

  The present invention resides in a photosensitive resin composition for an insulating film, an insulating film, and an image display device. More specifically, the present invention relates to a photosensitive resin composition useful for forming an insulating film of an image display device such as a liquid crystal display device or an organic electroluminescence device.

Conventionally, in a TFT active matrix substrate used in a liquid crystal display device, an interlayer insulating film is formed between a TFT array element and a transparent conductive film that forms a pixel electrode. In the interlayer insulating film, a contact hole for connecting the drain electrode of the TFT array and the wiring formed by the transparent conductive film is formed. Therefore, a photosensitive resin composition that can be patterned by development is generally used for the insulating film.
As liquid crystal display devices become more highly integrated and thinner, an increase in wiring delay time and crosstalk due to an increase in wiring resistance and inter-wiring capacitance becomes a problem. These solutions include reduction of wiring resistance and wiring capacitance. In the latter case, it is desired to lower the dielectric constant of the insulating film.
In order to lower the dielectric constant of the insulating film, there are a method of forming the insulating film with a material having a low relative dielectric constant and a method of making the insulating film porous (Patent Documents 1 and 2).
On the other hand, hydrocarbon materials such as polyethylene, fluororesins, and resins containing long-chain alkyl groups are known as materials having a low relative dielectric constant (Patent Document 3).
On the other hand, a method using a compound having two ethylenically unsaturated groups is known as a photosensitive resin composition for an insulating film having excellent peelability after exposure / development and excellent chemical resistance after thermosetting. (Patent Document 4).

JP 2011-154214 A JP 2005-134908 A JP 2013-82880 A JP 2008-052249 A

When the present inventors examined, although the porous film like patent document 1 and 2 shows a low dielectric constant, there exists a problem which a crack generate | occur | produces and transparency, mechanical strength, and insulation are low. It was found. Further, it has been found that there is a problem that applicable layer configuration and materials are limited to those having heat resistance because high temperature heat treatment at around 400 ° C. is performed when forming the porous film.
In addition, the resin described in Patent Document 3 cannot be alkali-developed, and can be improved in alkali developability by introducing a highly polar functional group such as a carboxyl group or a hydroxyl group into the resin. The rate was found to be high.
Furthermore, Patent Document 4 does not describe or suggest the relative dielectric constant, and the present inventors have examined the relative dielectric constant of the photosensitive resin composition described in the document. It was found to be insufficient.
Therefore, an object of the present invention is to provide a photosensitive resin composition for an insulating film that does not require high-temperature heat treatment, has excellent developability, and can form an insulating film having a sufficiently low relative dielectric constant.

As a result of intensive studies on the above problems, the present inventors have found that a specific photosensitive resin composition can achieve the above object, and have completed the present invention.
That is, the gist of the present invention is as follows.

[1] A photosensitive resin composition for an insulating film comprising (A) an alkali-soluble resin, (B) a photocurable monomer, (C) a photopolymerization initiator, and (D) a solvent,
The (A) alkali-soluble resin contains a resin (a) having a repeating unit derived from (meth) acrylic acid,
(B) the photocurable monomer contains a compound having two or three (meth) acryloyloxy groups linked by an aliphatic group which may be interrupted by an oxygen atom, and
In the photosensitive resin composition, the mass ratio of the (A) alkali-soluble resin to the (B) photocurable monomer is 1.2 or more.

[2] A photosensitive resin composition for an insulating film comprising (A) an alkali-soluble resin, (B) a photocurable monomer, (C) a photopolymerization initiator, and (D) a solvent,
The (A) alkali-soluble resin contains a resin (a) having a repeating unit derived from (meth) acrylic acid,
(B) the photocurable monomer contains a compound having two or three (meth) acryloyloxy groups linked by an aliphatic group which may be interrupted by an oxygen atom, and
A photosensitive resin composition for an insulating film, wherein the acid value of the photosensitive resin composition is 55 mg-KOH / g or more.

[3] The photosensitive resin composition for an insulating film according to [1] or [2], wherein the content ratio of the repeating unit derived from (meth) acrylic acid in the resin (a) is 20 mol% or more.

[4] The photosensitive resin for insulating films according to any one of [1] to [3], wherein the resin (a) further has a repeating unit derived from a (meth) acrylate compound containing an aliphatic hydrocarbon group. Composition.

[5] An insulating film obtained by curing the photosensitive resin composition for an insulating film according to any one of [1] to [4].

[6] An image display device comprising the insulating film according to [5].

  According to the present invention, it is possible to provide a photosensitive resin composition for an insulating film that does not require high-temperature heat treatment, is excellent in developability, and can form an insulating film having a sufficiently low relative dielectric constant.

  Embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention does not exceed the gist thereof. The content of is not specified.

  In the present invention, “(meth) acryl” means “acryl and / or methacryl”, and the same applies to “(meth) acrylate” and “(meth) acryloyl”.

  In the present invention, the “total solid content” means all components other than the solvent contained in the photosensitive resin composition.

In the present invention, the weight average molecular weight refers to a polystyrene equivalent weight average molecular weight (Mw) by GPC (gel permeation chromatography).

[Photosensitive resin composition for insulating film]
The photosensitive resin composition for an insulating film according to the first aspect of the present invention includes (A) an alkali-soluble resin, (B) a photocurable monomer, (C) a photopolymerization initiator, and (D) a solvent. ,
The (A) alkali-soluble resin contains a resin (a) having a repeating unit derived from (meth) acrylic acid,
(B) the photocurable monomer contains a compound having two or three (meth) acryloyloxy groups linked by an aliphatic group which may be interrupted by an oxygen atom, and
In the photosensitive resin composition, the mass ratio of the (A) alkali-soluble resin to the (B) photocurable monomer is 1.2 or more.

Moreover, the photosensitive resin composition for insulating films according to the second aspect of the present invention includes (A) an alkali-soluble resin, (B) a photocurable monomer, (C) a photopolymerization initiator, and (D) a solvent. Including
The (A) alkali-soluble resin contains a resin (a) having a repeating unit derived from (meth) acrylic acid,
(B) the photocurable monomer contains a compound having two or three (meth) acryloyloxy groups linked by an aliphatic group which may be interrupted by an oxygen atom, and
The acid value of the photosensitive resin composition is 55 mg-KOH / g or more.

Next, each component used for the slow release resin composition of the present embodiment will be described. Hereinafter, both the first and second aspects will be described together unless otherwise specified.

In addition to the essential components (A) to (D) described above, the photosensitive resin composition for an insulating film of the present invention can also contain the following components.
(E) Additive (F) Thermal crosslinking agent

  Hereinafter, each component will be described.

[(A) Alkali-soluble resin]
The (A) alkali-soluble resin used in the photosensitive resin composition for an insulating film of the present invention is not particularly limited as long as it is a resin that is soluble in an alkaline solution.
Examples of such alkali-soluble resins include acrylic resin, epoxy resin, polyamide, polyester, polyether, polyurethane, polyvinyl butyral, polyvinyl alcohol, polyvinyl pyrrolidone, and cellulose. Among them, a resin containing a carboxyl group, a hydroxyl group or an epoxy group is preferable from the viewpoint of enhancing the solubility in an alkali solution.
(A) Alkali-soluble resin may be used individually by 1 type, or may mix and use 2 or more types of resin.

[Resin (a) having a repeating unit derived from (meth) acrylic acid]
The (A) alkali-soluble resin used in the photosensitive resin composition for an insulating film of the present invention contains a resin (a) having a repeating unit derived from (meth) acrylic acid. The resin (a) is not particularly limited as long as it has a repeating unit derived from (meth) acrylic acid, and may be composed of only a repeating unit derived from (meth) acrylic acid, or (meth) acrylic. It may contain an acid-derived repeating unit and other repeating units. In addition, the repeating unit derived from (meth) acrylic acid means a repeating unit represented by the following general formula (a-1).

In formula (a-1), R ¹ represents a hydrogen atom or a methyl group.
The repeating unit derived from (meth) acrylic acid has high solubility in an alkali developer, and is acidified by heat treatment, so that the resin (a) after heat treatment tends to exhibit a low relative dielectric constant.

  The resin (a) is a copolymer of a repeating unit derived from (meth) acrylic acid and a repeating unit derived from another vinyl compound from the viewpoint of excellent developability and low dielectric constant. preferable.

Other vinyl compounds include aromatic group-containing vinyl compounds such as styrene, α-methylstyrene, hydroxystyrene, and benzyl (meth) acrylate;
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, cyclohexyl (meth) acrylate, n-hexyl (meth) acrylate, dodecyl (meth) acrylate, (Meth) acrylate compounds containing aliphatic hydrocarbon groups such as 2-ethylhexyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, isobornyl (meth) acrylate, and dicyclopentanyl (meth) acrylate ;
Glycidyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N- (meth) acryloylmorpholine, (meth) acrylonitrile, (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl ( Examples thereof include vinyl compounds such as (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, and vinyl acetate. These may be used alone or in combination of two or more.

  Among them, from the viewpoint of lowering the dielectric constant, it contains an aliphatic hydrocarbon group such as cyclohexyl (meth) acrylate, n-hexyl (meth) acrylate, cyclopentanyl (meth) acrylate, 2-ethylhexyl (meth) acrylate ( A meth) acrylate compound is preferred.

  The chemical structure of the repeating unit derived from a (meth) acrylate compound containing an aliphatic group hydrocarbon group is not particularly limited, but is represented by the following general formula (a-2) from the viewpoint of reducing the relative dielectric constant. Preferably there is.

In formula (a-2), R ² represents a hydrogen atom or a methyl group. R ³ represents an aliphatic hydrocarbon group.

  The aliphatic hydrocarbon group may be linear, branched or cyclic, but is preferably branched or cyclic from the viewpoint of increasing the molar volume fraction and decreasing the relative dielectric constant.

  The number of carbon atoms of the aliphatic hydrocarbon group is not particularly limited, but is usually 1 or more, preferably 4 or more, more preferably 6 or more, more preferably 20 or less, more preferably 15 or less, and further preferably 10 or less. preferable. When it is at least the lower limit value, the dielectric constant tends to decrease, and when it is at most the upper limit value, developability tends to be improved.

  The acid value of the resin (a) is preferably 30 mg-KOH / g or more, more preferably 50 mg-KOH / g or more, further preferably 80 mg-KOH / g or more, particularly preferably 100 mg-KOH / g or more, preferably It is 250 mg-KOH / g or less, More preferably, it is 200 mg-KOH / g or less, More preferably, it is 160 mg-KOH / g or less. When the amount is not less than the lower limit, the residue during development tends to be reduced, and when the amount is not more than the upper limit, the residual film ratio after development tends to be improved.

  The molecular weight of the resin (a) is usually 1,000 or more, preferably 3,000 or more, more preferably 5,000 or more, more preferably 6,000 or more, and further preferably 7,000 or more. 000 or less, preferably 50,000 or less, more preferably 30,000 or less, particularly preferably 20,000 or less, particularly preferably 10,000 or less, and even more preferably 9,000 or less. When the amount is not less than the lower limit, the remaining film ratio after development tends to be improved, and when the amount is not more than the upper limit, developability tends to be improved.

  The content ratio of the repeating unit derived from (meth) acrylic acid contained in the resin (a) is preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 30 mol% or more, still more preferably 35 mol% or more, particularly preferably. Is 40 mol% or more, preferably 90 mol% or less, more preferably 80 mol% or less, further preferably 70 mol% or less, still more preferably 60 mol% or less, and particularly preferably 50 mol% or less. By setting it to the lower limit value or more, developability is improved and the relative dielectric constant tends to be lowered. Moreover, there exists a tendency for the residual-film rate after image development to improve below the said upper limit.

  When the resin (a) has a repeating unit derived from a (meth) acrylate compound containing an aliphatic hydrocarbon group, the content is preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more, more More preferably 40 mol% or more, particularly preferably 50 mol% or more, preferably 90 mol% or less, more preferably 80 mol% or less, still more preferably 70 mol% or less, even more preferably 65 mol% or less, particularly preferably 60 mol% or less. It is. There exists a tendency for a dielectric constant to fall by setting it as the said lower limit or more. Moreover, there exists a tendency for developability to improve by setting it as the said upper limit or less.

  Moreover, (A) alkali-soluble resin of this invention may contain other resin other than resin (a) which has a repeating unit derived from (meth) acrylic acid. Other resins that can be used in the present invention are not particularly limited as long as they are soluble in an alkaline solution, and known resins can be used. Examples of such alkali-soluble resins include acrylic resins other than the resin (a), epoxy resins, polyamides, polyesters, polyethers, polyurethanes, polyvinyl butyral, polyvinyl alcohol, polyvinyl pyrrolidone, and acetyl cellulose. Of these, acrylic resins are preferred from the viewpoint of improving developability. From the viewpoint of improving heat resistance, an epoxy resin is preferable. These can be used individually by 1 type or in mixture of multiple types.

  The content ratio of the (A) alkali-soluble resin in the photosensitive resin composition for an insulating film of the present invention is not particularly limited, but is preferably 20% by mass or more, more preferably 30% by mass or more, based on the total solid content. Preferably 40% by weight or more, particularly preferably 50% by weight or more, even more preferably 55% by weight or more, and preferably 90% by weight or less, more preferably 80% by weight or less, even more preferably 75% by weight or less, particularly preferably Is 70% by mass or less. When the amount is not less than the lower limit, the remaining film ratio tends to increase, and when the amount is not more than the upper limit, there is a tendency that residues during development can be reduced.

  The content ratio of the resin (a) in the alkali-soluble resin (A) of the present invention is not particularly limited, but is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and particularly preferably 90%. It is 95 mass% or more, More preferably, it is 95 mass% or more, and is 100 mass% or less normally. There exists a tendency for a dielectric constant to fall by setting it as the said lower limit or more.

[(B) Photocurable monomer]
The (B) photocurable monomer used in the photosensitive resin composition for an insulating film of the present embodiment means a compound having at least one ethylenically unsaturated bond in the molecule.
In the present invention, as the (B) photocurable monomer, a compound having two or three (meth) acryloyloxy groups linked by an aliphatic group which may be interrupted by an oxygen atom is suitably used. .

  The chemical structure of the compound having two or three (meth) acryloyloxy groups linked by an aliphatic group which may be interrupted by an oxygen atom includes the following formulas (b-1) and (b-2): Can be mentioned.

In formula (b-1), R ⁴ and R ⁵ each independently represents a hydrogen atom or a methyl group. R ⁶ represents a divalent aliphatic group which may be interrupted with an oxygen atom.

In formula (b-2), R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom or a methyl group. R ¹⁰ represents a trivalent aliphatic group which may be interrupted with an oxygen atom.

Here, examples of the divalent aliphatic group for R ⁶ include linear, branched and cyclic aliphatic hydrocarbon groups.

  The straight aliphatic hydrocarbon group preferably has 1 or more carbon atoms, more preferably 4 or more, still more preferably 6 or more, preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less. When it is at least the lower limit value, the dielectric constant tends to decrease, and when it is at most the upper limit value, developability tends to be improved.

  Specific examples of the linear aliphatic hydrocarbon group include methane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, and pentane-1,5. -Diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl and the like.

  The number of oxygen atoms interrupting the linear aliphatic hydrocarbon group is preferably 0 or more, more preferably 1 or more, further preferably 2 or more, preferably 5 or less, more preferably 4 or less, and still more preferably 3 or less. There exists a tendency for developability to improve by making it into the said lower limit or more, and there exists a tendency for a dielectric constant to fall by making it into the said upper limit or less.

  Specific examples of the compound having two (meth) acryloyloxy groups linked by a divalent linear aliphatic hydrocarbon group which may be interrupted by an oxygen atom include 1,4-butanediol di (meth) Acrylate, 1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,7-heptanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, Examples include 1,9-nonanediol di (meth) acrylate and 1,10-decanediol di (meth) acrylate.

  The branched aliphatic hydrocarbon group preferably has 3 or more carbon atoms, more preferably 4 or more, still more preferably 6 or more, preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less. When it is at least the lower limit value, the dielectric constant tends to decrease, and when it is at most the upper limit value, developability tends to be improved.

  Specific examples of the branched chain aliphatic hydrocarbon group include 1-methylethane-1,2-diyl, 2-methylpropane-1,3-diyl, 2,2-dimethylpropane-1,3-diyl, and 3-methyl. -1,5-pentanediyl, 2-methyl-1,8-octanediyl and the like.

  The number of oxygen atoms interrupting the branched chain aliphatic hydrocarbon group is preferably 0 or more, more preferably 1 or more, still more preferably 2 or more, preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. There exists a tendency for developability to improve by making it into the said lower limit or more, and there exists a tendency for a dielectric constant to fall by making it into the said upper limit or less.

  Specific examples of the compound having two (meth) acryloyloxy groups linked by a divalent branched aliphatic hydrocarbon group which may be interrupted by an oxygen atom include neopentyl glycol di (meth) acrylate, 3 -Methyl-1,5-pentanediol di (meth) acrylate, 2-methyl-1,8-octanediol di (meth) acrylate and the like.

  The number of carbon atoms of the cyclic aliphatic hydrocarbon group is preferably 4 or more, more preferably 6 or more, still more preferably 10 or more, preferably 20 or less, more preferably 15 or less. When it is at least the lower limit value, the dielectric constant tends to decrease, and when it is at most the upper limit value, developability tends to be improved.

  Specific examples of the cyclic aliphatic hydrocarbon group include a cyclohexane ring, a cyclooctane ring, a cyclodecane ring, an adamantane ring, a norbornane ring, a bornane ring, a decalin ring, a perhydrofluorene ring, and a perhydroanthracene ring.

  The number of oxygen atoms interrupting the branched chain aliphatic hydrocarbon group is preferably 0 or more, more preferably 1 or more, still more preferably 2 or more, preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. There exists a tendency for developability to improve by making it into the said lower limit or more, and there exists a tendency for a dielectric constant to fall by making it into the said upper limit or less.

  Specific examples of the compound having two (meth) acryloyloxy groups linked by a divalent cyclic aliphatic group which may be interrupted by an oxygen atom include tricyclodecane dimethanol di (meth) acrylate, 1 , 3-adamantanediol di (meth) acrylate, 1,3-adamantane dimethanol di (meth) acrylate, adamantanetriol tri (meth) acrylate, di (meth) acrylate compound having a structure represented by the following formula (I) Etc.

In the above formula (I), R ¹¹ and R ¹² each independently represents a hydrogen atom or a methyl group.

On the other hand, examples of the trivalent aliphatic group for R ¹⁰ include linear, branched and cyclic aliphatic hydrocarbon groups. Of these, branched chain aliphatic hydrocarbons are preferred from the viewpoint of lowering the dielectric constant.
The number of carbon atoms of the aliphatic hydrocarbon group is preferably 3 or more, more preferably 4 or more, still more preferably 6 or more, preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less. When it is at least the lower limit value, the dielectric constant tends to decrease, and when it is at most the upper limit value, developability tends to be improved.

  Specific examples of the aliphatic hydrocarbon constituting the aliphatic hydrocarbon group include propane, butane, pentane, hexane, heptane, octane, nonane, decane, and the like, and preferably each of which is a branched chain. . The trivalent aliphatic hydrocarbon group means a trivalent group generated by losing 3 hydrogen atoms from the aliphatic hydrocarbon.

  The number of oxygen atoms interrupting the aliphatic hydrocarbon group is preferably 0 or more, more preferably 1 or more, still more preferably 2 or more, preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. There exists a tendency for developability to improve by making it into the said lower limit or more, and there exists a tendency for a dielectric constant to fall by making it into the said upper limit or less.

  Specific examples of the compound having three (meth) acryloyloxy groups linked by a trivalent branched aliphatic hydrocarbon group which may be interrupted by an oxygen atom include trimethylolpropane tri (meth) acrylate and the like. Can be mentioned.

These can be used alone or in combination of two or more.
In addition, (B) the photocurable monomer of the present invention is other than the above-mentioned “compound having two or three (meth) acryloyloxy groups linked by an aliphatic group optionally interrupted by an oxygen atom”. In addition, other photocurable monomers may be included.

  Examples of the other photocurable monomer (b) used in the present invention include “compounds having an ethylenically unsaturated group” described in JP-A-2008-52251. Among these photocurable monomers, preferred are esters of unsaturated carboxylic acids and polyhydroxy compounds. Among them, from the viewpoint of increasing the remaining film ratio after development, a compound having 3 or more ethylenically unsaturated bonds in the molecule is preferable. Specifically, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide addition tri (Meth) acrylate, glycerol tri (meth) acrylate, glycerol propylene oxide addition tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol Examples include hexa (meth) acrylate.

  Although the content rate of the (B) photocurable monomer in the photosensitive resin composition for insulating films is not specifically limited, It is 1 mass% or more normally with respect to the total solid, Preferably it is 10 mass% or more, More Preferably 20% by mass or more, more preferably 25% by mass or more, still more preferably 30% by mass or more, particularly preferably 35% by mass or more, usually 90% by mass or less, preferably 70% by mass or less, more preferably 60% by mass. % Or less, more preferably 50% by mass or less, still more preferably 45% by mass or less, and particularly preferably 40% by mass or less. When the amount is not less than the above lower limit value, residues at the time of development tend to be reduced, and when the amount is not more than the above upper limit value, the remaining film ratio tends to increase.

  In the photosensitive resin composition for an insulating film according to the first aspect of the present invention, in the photosensitive resin composition, the mass ratio of the (A) alkali-soluble resin to the (B) photocurable monomer is 1. .2 or more. Here, “(B) Mass ratio of (A) alkali-soluble resin to photocurable monomer” is the content ratio (% by mass) of (A) alkali-soluble resin in the photosensitive resin composition for insulating film ( B) It is defined by a value divided by the content (mass%) of the photocurable monomer. “(B) Mass ratio of (A) alkali-soluble resin to photocurable monomer” is preferably 1.3 or more, more preferably 1.4 or more, still more preferably 1.5 or more, and preferably It is 10 or less, more preferably 5 or less, and further preferably 3 or less. When it is at least the lower limit value, the dielectric constant tends to decrease, and when it is at most the upper limit value, developability tends to be improved.

  The content ratio of the compound having two or three (meth) acryloyloxy groups linked by an aliphatic group that may be interrupted by an oxygen atom in the photocurable monomer (B) of the present invention is particularly limited. However, it is preferably at least 50% by weight, more preferably at least 70% by weight, even more preferably at least 80% by weight, particularly preferably at least 90% by weight, even more preferably at least 95% by weight, and usually at most 100% by weight. It is. There exists a tendency for a dielectric constant to fall by setting it as the said lower limit or more.

[(C) Photopolymerization initiator]
As the (C) photopolymerization initiator used in the photosensitive resin composition for an insulating film, any known photopolymerization initiator can be used, and generates a radical that polymerizes an ethylenically unsaturated group from ultraviolet to visible light. The compound which can be mentioned is mentioned.

  (I) 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2 Halomethylated triazines such as-(4-ethoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-ethoxycarbonylnaphthyl) -4,6-bis (trichloromethyl) -s-triazine Derivative.

  (Ii) halomethylated oxadiazole derivative, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-bis (3′-methoxyphenyl) imidazole 2 2-mer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methylphenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl)- Imidazole derivatives such as 4,5-diphenylimidazole dimer.

(Iii) Benzoin and benzoin alkyl ethers such as benzoin methyl ether, benzoin phenyl ether, benzoin isobutyl ether and benzoin isopropyl ether.
(Iv) Anthraquinone derivatives such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone.

(V) A benzanthrone derivative.
(Vi) Benzophenone derivatives such as benzophenone, Michler's ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone.

  (Vii) 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- ( p-isopropylphenyl) ketone, 1-hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloro Acetophenone derivatives such as methyl- (p-butylphenyl) ketone.

  (Viii) Thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone.

(Ix) Benzoic acid ester derivatives such as ethyl p-dimethylaminobenzoate and ethyl p-diethylaminobenzoate.
(X) Acridine derivatives such as 9-phenylacridine and 9- (p-methoxyphenyl) acridine.
(Xi) Phenazine derivatives such as 9,10-dimethylbenzphenazine.

  (Xii) dicyclopentadienyl-Ti-dichloride, dicyclopentadienyl-Ti-bisphenyl, dicyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1- , Dicyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, dicyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1- , Dicyclopentadienyl-Ti-2,6-difluorophen-1-yl, dicyclopentadienyl-Ti-2,4-difluorophen-1-yl, dimethylcyclopentadienyl-Ti-bis- 2,3,4,5,6-pentafluorophen-1-yl, dimethylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, dicyclopenta Enyl -Ti-2,6-difluoro-3- (pyrr-1-yl) - titanocene derivatives such as 1-yl.

  (Xiii) 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1-one 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 4-dimethylaminoethylbenzoate, 4-dimethylaminoisoamylbenzoate, 4-diethylaminoacetophenone, 4-dimethylaminopropio Such as phenone, 2-ethylhexyl-1,4-dimethylaminobenzoate, 2,5-bis (4-diethylaminobenzal) cyclohexanone, 7-diethylamino-3- (4-diethylaminobenzoyl) coumarin, 4- (diethylamino) chalcone, etc. α-aminoalkylphenone compounds.

(Xiv) acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide.
(Xv) 1,2-octanedione-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime), ethanone-1- [9-ethyl-6- (2-methylbenzoyl) -9H- Carbazol-3-yl] -1- (O-acetyloxime)
(Xvi) JP 2000-80068 A, JP 2001-233842 A, JP 2001-235858 A, JP 2005-182004 A, WO 2002/00903 pamphlet, and JP 2007-041493 A. Oxime derivatives represented by the compounds described in Japanese Patent Publication No.
Among them, one kind or a mixture of two or more kinds can be used.

  Among these, from the viewpoint of improving curability, it is preferable to use an α-aminoalkylphenone compound. From the viewpoint of improving transparency, oxime derivatives are preferred.

  The content ratio of the photopolymerization initiator (C) in the photosensitive resin composition for insulating film is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, based on the total solid content. More preferably, it is 1% by mass or more, particularly preferably 3% by mass or more, preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 10% by mass or less. There exists a tendency which can improve the sclerosis | hardenability at the time of exposure by setting it as the said lower limit or more, and there exists a tendency which developability improves by setting it as the said upper limit or less.

[(D) Solvent]
The organic solvent is not particularly limited as long as it can dissolve and disperse the above-described components and has good handleability.

Specifically, for example, methyl cellosolve, ethyl cellosolve, butyl cellosolve, diethylene glycol monomethyl ether, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol monomethyl ether acetate (hereinafter sometimes abbreviated as “PGMAc”), methyl ethyl ketone. , Methyl isobutyl ketone, cyclohexanone, toluene, chloroform, dichloromethane, ethyl acetate, methyl lactate, ethyl lactate, 3-methoxymethyl propionate, 3-ethoxyethyl propionate, propylene glycol monomethyl ether, methanol, ethanol, propanol, butanol , Tetrahydrofuran, diethylene glycol dimethyl ether, methoxybutyl acetate, Best, carbitol, and the like. Among these, propylene glycol monomethyl ether, PGMAc, 3-methoxy-1-butanol, and 3-methoxy-1-butyl acetate are preferable from the viewpoint of applicability.
The boiling point of the organic solvent at 1013.25 hPa is preferably in the range of 100 to 200 ° C, more preferably in the range of 120 to 170 ° C.
Moreover, the organic solvent can also be used individually by 1 type, However, 2 or more types may be mixed and used.
Using the organic solvent, the total solid concentration of the photosensitive resin composition for insulating film is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 20% by mass or more, and particularly preferably 25% by mass. % Or more, preferably 60% by mass or less, more preferably 50% by mass or less, further preferably 40% by mass or less, and particularly preferably 35% by mass or less. There exists a tendency which can form the insulating film of a desired film thickness by setting it as the said lower limit or more, and there exists a tendency for the film thickness uniformity of an insulating film to improve by setting it as the said upper limit or less.

[(E) Additive]
The photosensitive resin composition for an insulating film in the present invention is a nonionic, anionic, cationic, amphoteric surfactant, for the purpose of improving the coating property of the composition as a coating liquid and the developing property of the insulating film, etc. Or you may contain surfactant, such as a fluorine type and a silicone type.

  The content of the surfactant is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and 5% by mass in the total solid content. % Or less is preferable, 3% by mass or less is more preferable, and 1% by mass or less is more preferable. When it is at least the lower limit value, the uniformity of the film tends to be improved, and when it is at most the upper limit value, the relative dielectric constant tends to decrease.

  In addition to the above, the photosensitive resin composition for an insulating film includes an adhesion improver such as a silane coupling agent, an ultraviolet absorber, a polymerization inhibitor, a coating improver, a development improver, an antioxidant, a pigment derivative, etc. Various additives such as a stabilizer, a flame retardant, inorganic particles, organic particles, a viscosity modifier, and a surface treatment agent may be included for the purpose of imparting further functions.

[(F) Thermal crosslinking agent]
The photosensitive resin composition for an insulating film of the present invention may contain a thermal crosslinking agent for the purpose of improving the heat resistance, chemical resistance and adhesion of the film after heat treatment (firing).
As the thermal crosslinking agent, a known thermal crosslinking agent such as “thermal crosslinking agent” described in JP-A-2008-052251 can be used as long as it undergoes a crosslinking reaction by baking after image formation by exposure and development. it can.
The content ratio of the thermal crosslinking agent in the photosensitive resin composition for an insulating film of the present invention is not particularly limited, but is preferably 60% by mass or less, more preferably 50% by mass or less, and still more preferably based on the total solid content. It is 30% by mass or less, preferably 0% or more, more preferably 1% by mass or more, further preferably 5% by mass or more, particularly preferably 10% by mass or more, and further preferably 20% by mass or more. By setting it to the upper limit value or less, the dielectric constant of the insulating film tends to decrease, and by setting the value to the lower limit value or more, the heat resistance of the insulating film tends to improve.

[Acid Value of Photosensitive Resin Composition for Insulating Film]
The acid value of the photosensitive resin composition for an insulating film according to the second aspect of the present invention is 55 mg-KOH / g or more.
Here, the “acid value of the photosensitive resin composition” represents the acid value per 1 g of the solid content of the photosensitive resin composition, and is measured in accordance with the neutralization titration of JIS-K0070 (standard oil and fat test method). Value. Moreover, when the measurement by the said method is difficult, you may calculate from the acid value of the compound contained in a component. The acid value of the photosensitive resin composition is preferably 55 mg-KOH / g or more, more preferably 60 mg-KOH / g or more, still more preferably 70 mg-KOH / g or more, and particularly preferably 75 mg-KOH / g or more. Preferably, it is 200 mg-KOH / g or less, More preferably, it is 150 mg-KOH / g or less, More preferably, it is 100 mg-KOH / g or less. When the amount is not less than the lower limit, the residue during development tends to be reduced, and when the amount is not more than the upper limit, the residual film ratio after development tends to be improved.

[Method for producing photosensitive resin composition for insulating film]
The photosensitive resin composition for an insulating film is (A) an alkali-soluble resin, (B) a photocurable monomer, (C) a photopolymerization initiator, and (D) a solvent. It can be prepared by mixing with E) an additive, (F) a thermal crosslinking agent, and other components to obtain a uniform solution. The mixing is preferably performed at room temperature, and is performed under ultraviolet light blocking so that the polymerization reaction does not start. Moreover, in each process, such as mixing, since fine dust may mix, it is preferable to filter the obtained photosensitive resin composition with a filter or the like.

[Method of forming insulating film]
An insulating film can be obtained by applying and curing the photosensitive resin composition for an insulating film of the present invention. In particular, the photosensitive resin composition for an insulating film of the present invention can be suitably used as a material for forming an insulating film. Below, the formation method of the insulating film using the photosensitive resin composition for insulating films of this invention is demonstrated.

[1-1] Coating Step Various known coating methods can be used for coating the photosensitive resin composition for an insulating film on the substrate on which the TFT array is formed. For example, it can apply | coat using application apparatuses, such as a spinner, a wire bar, a flow coater, a die coater, a roll coater, and a spray. The coating film thickness of the photosensitive resin composition for insulating films is usually 0.1 to 7 μm.

[1-2] Drying Step A volatile component is removed (dried) from the coating film to form a dry coating film. For drying, vacuum drying, hot plate, IR oven, convection oven or the like can be used. Preferred drying conditions are a temperature of 40 to 150 ° C. and a drying time of 30 seconds to 60 minutes.

[1-3] Exposure / Development Step Next, a photomask is placed on the dried coating film, and image exposure is performed through the photomask to form an exposure film. After exposure, an unexposed uncured portion is removed by the following development process to form a pattern. Note that post-exposure baking may be performed after exposure for the purpose of improving sensitivity before development. For baking in this case, a hot plate, an IR oven, a convection oven, or the like can be used. Post-exposure bake conditions are usually in the range of 40 to 150 ° C. and drying time of 10 seconds to 60 minutes.
Examples of the light source used in the exposure process of the dried coating film include a xenon lamp, a halogen lamp, a tungsten lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, a medium-pressure mercury lamp, a low-pressure mercury lamp, etc. And laser light sources such as excimer laser and nitrogen laser. When only light of a specific wavelength is used, an optical filter can be used.
The developer used in the development process is not particularly limited as long as it is a solvent capable of dissolving the coating film of the uncured part, but from the viewpoints of environmental pollution, harm to the human body, fire risk, etc. It is preferable to use an alkaline developer.
Examples of such alkali developer include inorganic alkali compounds such as sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, or diethanolamine, triethylamine, An aqueous solution containing an organic alkali compound such as ethanolamine or tetramethylammonium hydroxide can be mentioned.
The development processing method is not particularly limited, but it is usually carried out by immersion development, paddle development, spray development, brush development, ultrasonic development or the like at a development temperature of 10 to 50 ° C., preferably 15 to 45 ° C.

[1-4] Heat treatment step The film on which an image has been formed by the exposure / development step is then subjected to a heat treatment step to become a cured product (insulating film). A hot plate, IR oven, convection oven, or the like can be used for the heat treatment. The heat treatment conditions are usually 100 to 250 ° C. and a drying time of 30 seconds to 90 minutes.

[Image display device]
Next, a method for manufacturing the image display device (panel) of the present invention will be described. The image display device of the present invention is provided with an insulating film, and is usually provided with a TFT active matrix substrate on which an insulating film is formed.
Examples of the image display device include a liquid crystal display device and an organic EL display device.

  A TFT active matrix substrate is produced by forming the above composition as an insulating film on a substrate on which a TFT element array is formed, laminating an ITO film thereon, and then forming an ITO wiring using a photolithography method. Is done.

[2-1] Liquid Crystal Display Device The liquid crystal display device according to the present embodiment is manufactured by bonding the TFT active matrix substrate to the counter substrate to form a liquid crystal cell, injecting liquid crystal, and then connecting the counter electrode. can do.

  In general, a color filter substrate having an alignment film is preferably used as the counter substrate. As the alignment film, a resin film such as polyimide is suitable.

[2-2] Organic EL Display Device In the organic EL display device according to the present embodiment, a hole injection layer, a hole transport layer, a light emitting layer, an electron injection layer, and a cathode are sequentially formed on the TFT active matrix substrate. And how to do it. The organic EL display device thus manufactured can be applied to both a passive drive type organic EL display device and an active drive type organic EL display device.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.
In addition, the structural component of the photosensitive resin composition for insulating films used in the following Examples and Comparative Examples is as follows.

(A) Alkali-soluble resin a1:

  a2:

  a3:

  a4:

  a5:

  a6:

(B) Photocurable monomer B1: Nippon Kayaku Co., Ltd., R-604

  B2: Shin-Nakamura Chemical Co., Ltd., A-DCP

  B3: Kyoeisha Chemical Co., Ltd., NP-A

  B4: Kyoeisha Chemical Co., Ltd., 1.6HX-A

(C) Photopolymerization initiator C1: BASF, Irgacure 907
(D) Solvent D1: Propylene glycol monomethyl ether acetate (PGMAc)
(E) Additive E1: BYK330 (silicone surfactant) manufactured by Big Chemie

Evaluation of the photosensitive resin composition for an insulating film, its exposed film, and the insulating film was performed by the following method.
(Relative permittivity)
An insulating film was formed on the glass substrate on which chromium was vapor-deposited by the forming procedure in Examples and Comparative Examples. On the obtained insulating film, gold was deposited to a thickness of 100 nm by an ion coater to form a circular electrode having a diameter of 6 mm. A 1 kHz AC voltage was applied between the lower chromium film and the upper gold film, and the capacitance of the insulating film was measured with an LCR meter to determine the relative dielectric constant.

(Developability)
An exposure film was formed on a glass substrate (AN100, manufactured by Asahi Glass Co., Ltd.) by the formation procedure in Examples and Comparative Examples. The obtained film was immersed in a 2.4 mass% tetramethylammonium hydroxide aqueous solution for 30 seconds, then immersed in ultrapure water for 20 seconds, and washed with water. The developability was evaluated according to the following criteria.
○: When the unexposed part is completely dissolved and the exposed part remains without being completely dissolved ×: When both the unexposed part and the exposed part are completely dissolved or remains undissolved

(Film thickness)
The film thickness was evaluated from the level difference when a part of the sample was scraped off using a level difference / surface roughness / fine shape measuring device (Alpha Step IQ, manufactured by KLA Tencor Corporation). The measurement conditions are a measurement length of 1 mm, a scanning speed of 100 μm / sec, and a needle pressure of 3 mg.

(Examples 1-8, Comparative Examples 1-3)
Each component was mixed by the mixing | blending shown in Table 1, and it filtered with the filter made from polytetrafluoroethylene which has a 5-micrometer hole diameter, and prepared the photosensitive resin composition for insulating films. Mixing was performed at room temperature, and was carried out under ultraviolet light blocking so that the polymerization reaction did not start.
The insulating resin photosensitive resin composition was applied by spin coating, dried under reduced pressure for 1 minute, and then dried on a 90 ° C. hot plate for 90 seconds. Then, it exposed using the exposure apparatus (MA-1100, Dainippon Kaken company make), and obtained the exposure film | membrane. The exposure conditions at this time are an illuminance of 90 mW / cm ² and an exposure amount of 150 mJ / cm ² measured with an illuminometer having a wavelength of 365 nm. The exposed film was baked at 230 ° C. for 30 minutes in a clean oven (DE610, manufactured by Yamato Scientific Co., Ltd.) to obtain an insulating film. The insulating films of Examples 1 to 8 had good transparency and no cracks.
Various evaluations were performed on the exposure film and the insulating film. The results are shown in Table 1.

  As is apparent from the results in Table 1, the insulating film formed with the photosensitive resin composition for insulating film of the present embodiment had good developability and further exhibited a sufficiently low relative dielectric constant. There are two possible causes for this. One is that the alkali-soluble resin contains repeating units derived from (meth) acrylic acid, so that it exhibits good developability during development. After heat treatment, the carboxyl group derived from (meth) acrylic acid is converted to an acid anhydride, resulting in low dielectric constant. It is thought that the rate was shown. The other is considered to be the use of a compound having two or three (meth) acryloyloxy groups linked by a specific aliphatic group having a low relative dielectric constant as a photocurable monomer. It is done.

On the other hand, as in Comparative Example 1, the insulating film formed of a composition in which the alkali-soluble resin does not contain a repeating unit derived from (meth) acrylic acid has good developability, but has a sufficient dielectric constant. It did not show a low value. The alkali-soluble resin used in Comparative Example 1 does not contain a carboxyl group repeating unit derived from (meth) acrylic acid, while the carboxyl group contained is derived from tetrahydrophthalic anhydride, so that a decomposition reaction by heat treatment, etc. From this, it is considered that a hydroxyl group was formed, and the relative dielectric constant of the insulating film was increased.
On the other hand, as in Comparative Examples 2 and 3, an insulating film formed of a composition having a mass ratio of (A) the alkali-soluble resin to (B) the photocurable monomer of less than 1.2 is good development. However, the dielectric constant did not show a sufficiently low value. Resin (a) having a repeating unit derived from (meth) acrylic acid has a lower dielectric constant than (B) photocurable monomer, and (B) (A) alkali-soluble resin for photocurable monomer When the mass ratio is less than 1.2, the content of the resin (a) having a low relative dielectric constant in the insulating film is small, so it is considered that the value of the relative dielectric constant was not low.

  Further, as in Comparative Examples 2 and 3, the insulating film formed of the composition having an acid value of less than 55 mg-KOH / g does not show a sufficiently low relative dielectric constant. The low acid value of the photosensitive resin composition means that the relative dielectric constant is low because the content of the resin (a) having a repeating unit derived from (meth) acrylic acid as an acid group in the insulating film is small. It is thought that the value was not shown.

  The insulating film formed from the photosensitive resin composition for an insulating film of the present invention exhibits excellent developability and a sufficiently low relative dielectric constant, so that an image display such as a liquid crystal display device, an organic EL display device, electronic paper, etc. Applicable to the device. In addition, the present invention can be applied to insulating coating layers of various electronic components such as solid-state imaging devices, printed wiring boards, semiconductor integrated circuits, and color filters.

Claims (6)

A photosensitive resin composition for an insulating film comprising (A) an alkali-soluble resin, (B) a photocurable monomer, (C) a photopolymerization initiator, and (D) a solvent,
The (A) alkali-soluble resin contains a resin (a) having a repeating unit derived from (meth) acrylic acid,
(B) the photocurable monomer contains a compound having two or three (meth) acryloyloxy groups linked by an aliphatic group which may be interrupted by an oxygen atom, and
In the photosensitive resin composition, the mass ratio of the (A) alkali-soluble resin to the (B) photocurable monomer is 1.2 or more. A photosensitive resin composition for an insulating film comprising (A) an alkali-soluble resin, (B) a photocurable monomer, (C) a photopolymerization initiator, and (D) a solvent,
The (A) alkali-soluble resin contains a resin (a) having a repeating unit derived from (meth) acrylic acid,
(B) the photocurable monomer contains a compound having two or three (meth) acryloyloxy groups linked by an aliphatic group which may be interrupted by an oxygen atom, and
A photosensitive resin composition for an insulating film, wherein the acid value of the photosensitive resin composition is 55 mg-KOH / g or more.   The photosensitive resin composition for insulating films of Claim 1 or 2 whose content rate of the repeating unit derived from (meth) acrylic acid in the said resin (a) is 20 mol% or more.   The photosensitive resin composition for insulating films according to any one of claims 1 to 3, wherein the resin (a) further has a repeating unit derived from a (meth) acrylate compound containing an aliphatic hydrocarbon group.   The insulating film which hardened the photosensitive resin composition for insulating films of any one of Claims 1-4.   An image display device comprising the insulating film according to claim 5.