JP2014167560A - Photosensitive resin composition for interlayer insulating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition from which an interlayer insulating film having a low dielectric constant can be formed by low-temperature baking.SOLUTION: The photosensitive resin composition for an interlayer insulating film comprises an alkali-soluble resin (A), a photosensitive agent (B), and an organic solvent (C), wherein the alkali-soluble resin (A) comprises a copolymer having a structural unit (A1) expressed by general formula (a-1) below, a structural unit (A2) expressed by general formula (a-2) below, and an alicyclic epoxy group-containing unit (A3) in the copolymer structure. In general formula, Rand Rrepresent a hydrogen atom or a methyl group; Ra represents a hydrogen atom or an organic group having a hydroxyl group; and Rb represents a hydrocarbon group.

Description

  The present invention relates to a photosensitive resin composition for interlayer insulating films.

  In recent years, semiconductor devices have been highly integrated and increased in size, and there is a demand for further thinner and smaller package substrates. Along with this, it is required to form a surface protection layer of a semiconductor element, an interlayer insulation film, or an interlayer insulation film of a package substrate having a rewiring layer with a material having more excellent electrical characteristics, heat resistance, mechanical characteristics, etc. It has been.

  Polyimide resin (hereinafter referred to as “PI”) and polybenzoxazole (hereinafter referred to as “PBO”) are representative of materials that can satisfy such required characteristics. For example, photosensitive properties are imparted to PI and PBO. The use of photosensitive PI and photosensitive PBO that have been used has been studied. The use of these photosensitive resins has the advantage that the pattern formation process is simplified and the complicated manufacturing process can be shortened. In addition, compared with conventional vinyl-based photosensitive resins that can be alkali-developed by introducing a carboxyl group. Since it has high heat resistance and insulation resistance, it is effective as the interlayer insulating film (see, for example, Patent Documents 1 and 2).

  On the other hand, photosensitive PI and photosensitive PBO have problems such as a large change in varnish over time, a need for baking at a high temperature of about 350 to 400 ° C., and a large amount of film loss.

  On the other hand, an interlayer insulating film using a photosensitive acrylic resin having high heat resistance and good handleability has been proposed (Patent Document 3 and the like). However, the interlayer insulating film using the photosensitive acrylic resin has a high dielectric constant and may not be sufficient in terms of electrical characteristics.

JP 2011-180472 A JP 2007-031511 A JP 2006-215105 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a photosensitive resin composition capable of forming an interlayer insulating film having a low dielectric constant.

  The present inventors have found that an interlayer insulating film can have a low dielectric constant by introducing a specific structural unit into an acrylic resin, and have completed the present invention.

［前記一般式中、Ｒ^０は水素原子又はメチル基を表し、Ｒａは水素原子又は水酸基を有する有機基を表す。］

［前記一般式中、Ｒ^１は水素原子又はメチル基を表し、Ｒｂは炭化水素基を表す。］ The photosensitive resin composition for interlayer insulation films according to the present invention contains an alkali-soluble resin (A), a photosensitizer (B), and an organic solvent (C), and comprises an alkali-soluble resin (A). Are the structural unit (A1) represented by the following general formula (a-1), the structural unit (A2) represented by the following general formula (a-2), and the alicyclic epoxy group-containing unit (A3). In the structure.

[In the general formula, R ⁰ represents a hydrogen atom or a methyl group, and Ra represents a hydrogen atom or an organic group having a hydroxyl group. ]

[In the above general formula, R ¹ represents a hydrogen atom or a methyl group, and Rb represents a hydrocarbon group. ]

  The “structural unit” in the present invention refers to a unit derived from a polymerizable monomer that constitutes a copolymer.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the photosensitive resin composition which can form a low dielectric constant interlayer insulation film.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. .

  The photosensitive resin composition for interlayer insulating films according to the present invention (hereinafter simply referred to as “photosensitive resin composition”) includes an alkali-soluble resin (A) (hereinafter also referred to as component (A)) and a photosensitive agent. (B) (hereinafter also referred to as component (B)) and organic solvent (C) (hereinafter also referred to as component (C)).

［前記一般式中、Ｒ^０は水素原子又はメチル基を表し、Ｒａは水素原子又は水酸基を有する有機基を表す。］

［前記一般式中、Ｒ^１は水素原子又はメチル基を表し、Ｒｂは炭化水素基を表す。］ [Alkali-soluble resin (A)]
In the present invention, the component (A) includes the structural unit (A1) represented by the general formula (a-1), the structural unit (A2) represented by the following general formula (a-2), and an alicyclic epoxy. It contains at least a copolymer having a group-containing unit (A3) in its structure.

[In the general formula, R ⁰ represents a hydrogen atom or a methyl group, and Ra represents a hydrogen atom or an organic group having a hydroxyl group. ]

[In the above general formula, R ¹ represents a hydrogen atom or a methyl group, and Rb represents a hydrocarbon group. ]

  The photosensitive resin composition of the present invention contains a 2.38 mass% tetramethylammonium hydroxide aqueous solution generally used by containing a copolymer containing the structural unit (A1) as the component (A). It can be used and developed as it is. Furthermore, by having the alicyclic epoxy group-containing unit (A3) in the structure of the copolymer, it is possible to achieve both heat resistance and low dielectric constant in the case of an interlayer insulating film.

  The structural unit (A1) in the present invention is an acrylic acid or methacrylic acid ester unit in which Ra is a hydrogen atom or an organic group having a hydroxyl group. Here, the organic group is, for example, a branched, linear, or cyclic alkyl group, an aryl group that may have a substituent, a heteroaryl group that may have a substituent, or a substituent. An aralkyl group which may have a hetero-aralkyl group which may have a substituent or a hetero aralkyl group which may have a substituent can be mentioned, and the structure has one or more hydroxyl groups. The organic group preferably has 1 to 20 carbon atoms, more preferably 6 to 12 carbon atoms. A large carbon number is preferable in terms of storage stability and low dielectric constant of the interlayer insulating layer, and a small carbon number is excellent in resolution.

  As the structural unit (A1), when Ra is a hydrogen atom, that is, selecting methacrylic acid, acrylic acid, or the like is effective in increasing the alkali developability of the copolymer. Therefore, it is preferable to employ the above organic group having a hydroxyl group as the structural unit (A1).

［前記一般式中、Ｒ^０は水素原子又はメチル基を表し、Ｒ^２は単結合又は炭素数１〜５のアルキレン基を表し、Ｒ^３は炭素数１〜５のアルキル基を表し、ａは１〜５の整数を表し、ｂは０又は１〜４の整数を表し、ａ＋ｂは５以下である。なお、Ｒ^３が２以上存在する場合、これらのＲ^３は相互に異なっていてもよいし同じでもよい。］ Preferred examples of the structural unit (A1) include structural units represented by the following general formula (a-1-1).

[In the general formula, R ⁰ represents a hydrogen atom or a methyl group, R ² represents a single bond or an alkylene group having 1 to 5 carbon atoms, R ³ represents an alkyl group having 1 to 5 carbon atoms, and a represents The integer of 1-5 is represented, b represents the integer of 0 or 1-4, and a + b is 5 or less. In the case where R ³ is present 2 or more, these R ³ may be the same or may be different from each other. ]

In General Formula (a-1-1), R ⁰ can take a hydrogen atom or a methyl group, but is preferably a methyl group. R ² represents a single bond or a linear or branched alkylene group having 1 to 5 carbon atoms. Specific examples include a methylene group, an ethylene group, a propylene group, an isopropylene group, an n-butylene group, an isobutylene group, a tert-butylene group, a pentylene group, an isopentylene group, and a neopentylene group. Among them, a single bond, a methylene group, and an ethylene group are preferable. In particular, in the case of a single bond, alkali solubility can be improved, and heat resistance when an interlayer insulating film is further improved. It is also preferable.

Here, a represents an integer of 1 to 5, and it is preferable that a is 1 from the viewpoint of the effect of the present invention and the point that the production is easy. Moreover, the bonding position of the hydroxyl group in the benzene ring is preferably bonded to the 4-position when the carbon atom bonded to R ² is defined as the reference (first position).

R ³ is a linear or branched alkyl group having 1 to 5 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. Among these, a methyl group or an ethyl group is preferable from the viewpoint of easy production.

More specifically, examples of the structural unit (A1) include those represented by the following structural formulas (a-1-1a) and (a-1-1b). In particular, a structural unit represented by the structural formula (a-1-1a) is preferable.

  This structural unit (A1) is copolymerized with the structural unit (A2) represented by the general formula (a-2) and the alicyclic epoxy group-containing unit (A3), and optionally with other structural units. The copolymer can be alkali-soluble. The content ratio of the structural unit (A1) in the copolymer is preferably 20 to 60 mol%. More preferably, it is 35-55 mol%. The content ratio is preferably 20 mol% or more from the viewpoint of alkali developability, and 60 mol% or less is preferable from the viewpoint of reducing the dielectric constant of the interlayer insulating film.

  The structural unit (A2) in the present invention is an acrylic acid or methacrylic acid ester unit having a hydrocarbon group as Rb. Here, examples of the hydrocarbon group include a branched, linear, or cyclic alkyl group, an aryl group that may have a substituent, or an aralkyl group that may have a substituent. be able to. The hydrocarbon group preferably has 1 to 20 carbon atoms. Furthermore, as a branched and linear alkyl group, C1-C12 is preferable and 1-6 are the most preferable. The cyclic alkyl group preferably has 6 to 20 carbon atoms, and most preferably 6 to 12 carbon atoms. The aryl group which may have a substituent or the aralkyl group which may have a substituent preferably has 6 to 20 carbon atoms, and most preferably 6 to 12 carbon atoms. Alkali resolution is sufficient if the carbon number is 20 or less, and it is preferable if the carbon number is 1 or more because the dielectric constant of the interlayer insulating film can be reduced.

  Specifically, linear or branched alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, amyl acrylate, ethyl hexyl acrylate, octyl acrylate, and t-octyl acrylate; cyclohexyl acrylate, dicyclopentanyl Examples thereof include those derived from alicyclic alkyl acrylates such as acrylate, 2-methylcyclohexyl acrylate and isobornyl acrylate; benzyl acrylate, aryl acrylate (for example, phenyl acrylate) and the like.

  Alternatively, linear or branched alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, amyl methacrylate, hexyl methacrylate, octyl methacrylate; cyclohexyl methacrylate, Alicyclic alkyl methacrylates such as dicyclopentanyl methacrylate, 2-methylcyclohexyl methacrylate, and isobornyl methacrylate; those derived from benzyl methacrylate, aryl methacrylate (eg, phenyl methacrylate, cresyl methacrylate, naphthyl methacrylate, etc.) It is done.

  By introducing the structural unit (A2) into the copolymer, the dissolution speed of the copolymer can be adjusted. As the structural unit (A2), those derived from a monomer having an alicyclic group are particularly preferred from the viewpoint of reducing the dielectric constant of the interlayer insulating film.

  The alicyclic epoxy group-containing unit (A3) is not particularly limited as long as it is a structural unit having an alicyclic epoxy group in the structure and derived from a compound having an ethylenic double bond. As for carbon number of the alicyclic group of an alicyclic epoxy group, about 5-10 are preferable. By having the alicyclic epoxy group-containing unit (A3) in the copolymer of the present invention, the heat resistance is improved without adding a low molecular weight crosslinking component that causes outgassing to the photosensitive resin composition. It becomes possible.

  Specific examples of the alicyclic epoxy group-containing unit (A3) include those derived from alicyclic epoxy group-containing polymerizable unsaturated compounds represented by the following general formulas (1) to (31). .

In the formula, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a divalent hydrocarbon group having 1 to 8 carbon atoms, R ⁶ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, R ⁴ , R ⁵ and R ⁶ may be the same or different, and w represents an integer of 0 to 10.

  Among these, those represented by the general formulas (1) to (6), (14), (16), (18), (21), (23) to (25), and (30) are preferable. More preferably, they are general formula (1)-(6).

  The content ratio of the alicyclic epoxy group-containing unit (A3) in the copolymer is preferably 5 to 40 mol%. Furthermore, it is preferable that it is 10-30 mol%, and it is most preferable that it is 15-25 mol%. If the content ratio is 10 mol% or more, the heat resistance and adhesion of the interlayer insulating film can be improved, and if it is less than 40 mol%, the dielectric constant of the interlayer insulating film can be kept low.

  Further, the copolymer may contain a structural unit (A4) other than the structural units (A1) to (A3) as long as the object of the present invention is not violated. The structural unit is not particularly limited as long as it is a structural unit derived from a compound having an ethylenic double bond. Examples of such structural units include structural units selected from acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, styrenes, and the like.

  Specific examples of acrylamides include acrylamide and N-alkylacrylamide (the alkyl group preferably has 1 to 10 carbon atoms, such as methyl, ethyl, propyl, butyl, t-butyl, heptyl, Octyl group, cyclohexyl group, hydroxyethyl group, benzyl group and the like), N-arylacrylamide (as the aryl group, for example, phenyl group, tolyl group, nitrophenyl group, naphthyl group, hydroxyphenyl group, etc.), N, N-dialkylacrylamide (the alkyl group preferably has 1 to 10 carbon atoms), N, N-arylacrylamide (the aryl group includes, for example, a phenyl group), N-methyl-N-phenylacrylamide, N-hydroxyethyl -N-methylacrylamide, N-2-acetoami Ethyl -N- acetyl acrylamide.

  Specific examples of the methacrylamides include methacrylamide, N-alkylmethacrylamide (the alkyl group preferably has 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a t-butyl group, an ethylhexyl group, Hydroxyethyl group, cyclohexyl group and the like), N-aryl methacrylamide (the aryl group includes a phenyl group), N, N-dialkyl methacrylamide (the alkyl group includes an ethyl group, a propyl group, Butyl group and the like), N, N-diarylmethacrylamide (the aryl group includes phenyl group and the like), N-hydroxyethyl-N-methylmethacrylamide, N-methyl-N-phenylmethacrylamide, N- And ethyl-N-phenylmethacrylamide.

  Specific examples of allyl compounds include allyl esters (eg, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.) And allyloxyethanol.

  Specific examples of vinyl ethers include alkyl vinyl ethers (for example, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, etc.), vinyl aryl ethers (for example, vinyl phenyl ether, vinyl tolyl ether, Vinyl black Phenyl ether, vinyl 2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthranyl ether, etc.).

  Specific examples of vinyl esters include vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl Examples include butoxy acetate, vinyl phenyl acetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinyl benzoate, vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, and vinyl naphthoate.

  Specific examples of styrenes include styrene, alkyl styrene (for example, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, butyl styrene, hexyl styrene, cyclohexyl styrene, decyl styrene, benzyl styrene, chloro. Methyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, etc.), alkoxy styrene (eg methoxy styrene, 4-methoxy-3-methyl styrene, dimethoxy styrene, etc.), halogen styrene (eg chloro styrene, dichloro styrene, Trichlorostyrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, toner Fluorostyrene, 2-bromo-4-trifluoromethyl styrene, 4-fluoro-3-trifluoromethyl styrene etc.). Also included are acrylonitrile, methacrylonitrile and the like.

  As the other structural unit, it is preferable to select one derived from a monomer having an alicyclic group in terms of reducing the dielectric constant of the interlayer insulating film.

  The copolymer (A) has a mass average molecular weight (Mw: measured value by gel permeation chromatography (GPC) in terms of polystyrene) of preferably 2000 to 50000, and more preferably 5000 to 30000. When the molecular weight is 2000 or more, it can be easily formed into a film. Moreover, moderate alkali solubility can be obtained by setting the molecular weight to 50000 or less.

  The copolymer can be produced by known radical polymerization. That is, it can be produced by dissolving the polymerizable monomer for inducing the structural units (A1) to (A4) and a known radical polymerization initiator in a polymerization solvent and then stirring with heating.

  Furthermore, the alkali-soluble resin (A) may contain one or more other copolymers in addition to the copolymer containing the structural units (A1) to (A3). This copolymer is preferably 0 to 50 parts by mass, and more preferably 0 to 30 parts by mass with respect to 100 parts by mass of the copolymer (A). The copolymer has a mass average molecular weight (Mw: measured value in terms of polystyrene of gel permeation chromatography (GPC)) of preferably 2000 to 50000, and more preferably 5000 to 30000.

[Photosensitive agent (B)]
The photosensitive agent (B) in the present invention is not particularly limited as long as it is a compound that can be used as a photosensitive component, and preferred examples include a quinonediazide group-containing compound.

  Specific examples of the quinonediazide group-containing compound include completely esterified products and partially esterified products of a phenol compound (also referred to as a phenolic hydroxyl group-containing compound) and a naphthoquinonediazide sulfonic acid compound.

  Specific examples of the phenol compound include 2,3,4-trihydroxybenzophenone and polyhydroxybenzophenones such as 2,3,4,4′-tetrahydroxybenzophenone; tris (4-hydroxyphenyl) methane, Bis (4-hydroxy-3-methylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,3,5-trimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5- Dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, Bis (4-hydroxy-2,5-dimethylphenyl) -4-hydride Xiphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy- 3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) ) -2,4-dihydroxyphenylmethane, bis (4-hydroxyphenyl) -3-methoxy-4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -4-hydroxyphenylmethane, Bis (5-cyclohexyl-4-hydroxy-2-methylphenol ) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4 -Trisphenol type compounds such as dihydroxyphenylmethane, 4,4 '-[(3,4-dihydroxyphenyl) methylene] bis (2-cyclohexyl-5-methylphenol);

  Linear type 3 such as 2,4-bis (3,5-dimethyl-4-hydroxybenzyl) -5-hydroxyphenol, 2,6-bis (2,5-dimethyl-4-hydroxybenzyl) -4-methylphenol Nucleophilic phenol compound; 1,1-bis [3- (2-hydroxy-5-methylbenzyl) -4-hydroxy-5-cyclohexylphenyl] isopropane, bis [2,5-dimethyl-3- (4-hydroxy) -5-methylbenzyl) -4-hydroxyphenyl] methane, bis [2,5-dimethyl-3- (4-hydroxybenzyl) -4-hydroxyphenyl] methane, bis [3- (3,5-dimethyl-4) -Hydroxybenzyl) -4-hydroxy-5-methylphenyl] methane, bis [3- (3,5-dimethyl-4-hydroxybenzyl) -4-hydride Xyl-5-ethylphenyl] methane, bis [3- (3,5-diethyl-4-hydroxybenzyl) -4-hydroxy-5-methylphenyl] methane, bis [3- (3,5-diethyl-4-) Hydroxybenzyl) -4-hydroxy-5-ethylphenyl] methane, bis [2-hydroxy-3- (3,5-dimethyl-4-hydroxybenzyl) -5-methylphenyl] methane, bis [2-hydroxy-3 -(2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane, bis [4-hydroxy-3- (2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane, bis [2,5 -Linear tetranuclear phenolic compounds such as dimethyl-3- (2-hydroxy-5-methylbenzyl) -4-hydroxyphenyl] methane; 2,4- [2-hydroxy-3- (4-hydroxybenzyl) -5-methylbenzyl] -6-cyclohexylphenol, 2,4-bis [4-hydroxy-3- (4-hydroxybenzyl) -5-methylbenzyl] Linear pentanuclear phenol compounds such as -6-cyclohexylphenol and 2,6-bis [2,5-dimethyl-3- (2-hydroxy-5-methylbenzyl) -4-hydroxybenzyl] -4-methylphenol Linear polyphenol compounds such as

  Bis (2,3-trihydroxyphenyl) methane, bis (2,4-dihydroxyphenyl) methane, 2,3,4-trihydroxyphenyl-4'-hydroxyphenylmethane, 2- (2,3,4- Trihydroxyphenyl) -2- (2 ', 3', 4'-trihydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2- (2 ', 4'-dihydroxyphenyl) propane, 2- (4-hydroxyphenyl) -2- (4'-hydroxyphenyl) propane, 2- (3-fluoro-4-hydroxyphenyl) -2- (3'-fluoro-4'-hydroxyphenyl) propane, 2- ( 2,4-dihydroxyphenyl) -2- (4'-hydroxyphenyl) propane, 2- (2,3,4-trihydroxyphenyl) -2- (4'- Bisphenol type compounds such as loxyphenyl) propane, 2- (2,3,4-trihydroxyphenyl) -2- (4'-hydroxy-3 ', 5'-dimethylphenyl) propane; 1- [1- (4 -Hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, 1- [1- (3-methyl-4-hydroxyphenyl) isopropyl] -4- [1,1- Examples thereof include polynuclear branched compounds such as bis (3-methyl-4-hydroxyphenyl) ethyl] benzene; and condensed phenol compounds such as 1,1-bis (4-hydroxyphenyl) cyclohexane. These can be used alone or in combination of two or more.

  Examples of the naphthoquinone diazide sulfonic acid compound include naphthoquinone-1,2-diazide-5-sulfonic acid and naphthoquinone-1,2-diazide-4-sulfonic acid.

  In addition, other quinonediazide group-containing compounds such as orthobenzoquinonediazide, orthonaphthoquinonediazide, orthoanthraquinonediazide, or orthonaphthoquinonediazidesulfonic acid esters can be used. Further, orthoquinonediazidesulfonyl chloride and a compound having a hydroxyl group or an amino group (for example, phenol, p-methoxyphenol, dimethylphenol, hydroquinone, bisphenol A, naphthol, pyrocatechol, pyrogallol, pyrogallol monomethyl ether, pyrogallol-1,3 -Dimethyl ether, gallic acid, gallic acid esterified or etherified with some hydroxyl groups remaining, aniline, p-aminodiphenylamine, etc.) and the like can also be used. You may use these individually or in combination of 2 or more types.

  These quinonediazide group-containing compounds include, for example, a trisphenol type compound and naphthoquinone-1,2-diazide-5-sulfonyl chloride or naphthoquinone-1,2-diazide-4-sulfonyl chloride in a suitable solvent such as dioxane. It can be produced by condensation in the presence of an alkali such as triethanolamine, alkali carbonate, alkali hydrogencarbonate, etc., and complete esterification or partial esterification.

  Moreover, as said (B) component, it is preferable to use a non-benzophenone series quinonediazide group containing compound, and it is preferable to use a polynuclear branched type compound. The phenolic hydroxyl group-containing compound preferably has a gram extinction coefficient of 1 or less at a wavelength of 350 nm. Thereby, in the photosensitive resin composition, higher sensitivity can be obtained, and the transmittance (transparency) when an interlayer insulating film is formed can be improved. Furthermore, the phenolic hydroxyl group-containing compound preferably has a decomposition temperature of 300 ° C. or higher. Thereby, the transparency of the interlayer insulating film can be ensured.

  As such component (B), a quinonediazide group-containing compound is preferable, and a naphthoquinonediazidesulfonic acid ester is particularly preferable. Among them, 4,4 ′-[(3,4-dihydroxyphenyl) methylene] bis (2-cyclohexyl-5-methylphenol), 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1, A naphthoquinonediazide sulfonate esterified product such as 1-bis (4-hydroxyphenyl) ethyl] benzene can be suitably used.

  (B) As for content of a component, 10-40 mass% is preferable with respect to all the solid components, More preferably, it is 20-30 mass%. By setting the content of the component (B) to 10% by mass or more, the resolution can be improved. Further, it is possible to reduce the amount of pattern loss after the pattern is formed. Further, by setting the content of the component (B) to 40% by mass or less, it is possible to impart appropriate sensitivity and transmittance.

[Organic solvent (C)]
The photosensitive resin composition according to the present invention contains an organic solvent (C) in order to improve applicability and adjust viscosity.

  As component (C), benzene, toluene, xylene, methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, diethylene glycol, glycerin, ethylene glycol monomethyl ether, ethylene glycol Monoethyl ether, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 3-methoxybutyl acetate (MA), 3-methoxybutanol (BM) , 3-methyl- -Methoxybutyl acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, methyl carbonate, ethyl carbonate, propyl carbonate, butyl carbonate or a mixture thereof . Among these, it is preferable to use PGMEA, PGMEA, MA, a mixed solvent of PGME and PGMEA, a mixed solvent of MA and BM, and the like.

  Although the usage-amount of an organic solvent (C) is not specifically limited, It is a density | concentration which can be apply | coated to a board | substrate etc., and is suitably set according to a coating film thickness. Specifically, it is preferable to use the photosensitive resin composition so that the solid content concentration is in the range of 10 to 50% by mass, particularly 15 to 35% by mass.

[Other (D)]
Moreover, the photosensitive resin composition which concerns on this invention may contain various additives, such as surfactant, a sensitizer, an antifoamer, a crosslinking agent, and a coupling agent.

  The surfactant may be a conventionally known surfactant, and examples thereof include anionic, cationic, and nonionic compounds. Specific examples include X-70-090 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.). By adding the surfactant, the coating property and flatness can be improved.

  As the sensitizer, those used in conventionally known positive resists can be used. For example, a compound having a phenolic hydroxyl group having a molecular weight of 1000 or less can be used.

  As said antifoamer, a conventionally well-known thing may be used and a silicone type compound and a fluorine-type compound are mentioned.

  Moreover, as a crosslinking agent, the polymeric compound which has an ethylenically unsaturated bond is mentioned. Among such compounds, monofunctional, bifunctional, or trifunctional or higher (meth) acrylates are preferably used in terms of good polymerizability and improved strength of the resulting patterned thin film.

  As said coupling agent, a conventionally well-known thing may be used and an alkoxysilane type compound and a titanate compound are mentioned.

  In the photosensitive resin composition according to the present invention, for example, the component (A), the component (B), the component (C) and the component (D) are mixed (dispersed and kneaded) with a stirrer such as a roll mill, a ball mill, or a sand mill. And it can prepare by filtering with filters, such as a 5 micrometer membrane filter, as needed.

  The photosensitive resin composition according to the present invention is suitably used for forming an interlayer insulating film provided for insulating between wirings arranged in layers in electronic components such as liquid crystal display elements, integrated circuit elements, and solid-state imaging elements. be able to.

Hereinafter, a method for forming an interlayer insulating film using the photosensitive resin composition according to the present invention will be described.

[Method for forming interlayer insulating film]
First, the photosensitive resin composition according to the present invention is applied on a support such as a substrate using a spinner, a roll coater, a spray coater, a slit coater, or the like, and dried to form a photosensitive resin composition layer. Examples of the substrate include a glass plate that includes wiring such as a transparent conductive circuit, and includes a black matrix, a color filter, a polarizing plate, and the like as necessary.

  Examples of the drying method include (1) a method of drying on a hot plate at a temperature of 80 to 120 ° C. for 60 to 120 seconds, (2) a method of leaving at room temperature for several hours to several days, and (3) a temperature. Any of a method of removing the solvent by putting it in a wind heater or an infrared heater for several tens of minutes to several hours may be used. Moreover, the film thickness of the said photosensitive resin composition layer is although it does not specifically limit, It is preferable that it is about 1.0-5.0 micrometers.

Next, exposure is performed through a predetermined mask. This exposure is performed by irradiating active energy rays such as ultraviolet rays and excimer laser light. Examples of the active energy ray light source include a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp, and an excimer laser generator. Although the energy dose to be irradiated varies depending on the composition of the photosensitive resin composition, it may be, for example, about 30 to 2000 mJ / cm ² .

  Next, the exposed photosensitive resin composition layer is developed with a developer to form a pattern. Examples of the developer include an organic alkaline aqueous solution such as a tetramethylammonium hydroxide (TMAH) aqueous solution or an inorganic alkaline aqueous solution such as sodium hydroxide, potassium hydroxide, sodium metasilicate, and sodium phosphate. Thereby, an interlayer insulating film can be provided in a desired range. Finally, the pattern is cured by heating. As this heat-curing temperature, it is preferable to perform the heat treatment under conditions of 150 to 250 ° C. Further, it is preferable to expose the entire surface of the formed pattern.

[Preparation of alkali-soluble resin (A)]
A polymerizable monomer was mixed so that each component was comprised by the molar ratio shown by following Table 1, and acrylic 1-8 which is alkali-soluble resin (A) was prepared according to the usual method.

[Preparation of photosensitive resin composition]
Each alkali-soluble resin (A) shown in Table 1, the photosensitive agent (B), and the organic solvent (C) were mixed at the following blending ratio, and the photosensitive resin compositions of Examples 1 to 6 and Comparative Examples 1 and 2 were used. A product was prepared.
(A) Component: Polymer described in Table 1 75 parts by mass (B) Component: 4,4 ′-[(3,4-dihydroxyphenyl) methylene] bis (2-cyclohexyl-5-methylphenol) and naphtho Reacted with quinonediazide-5-sulfonic acid ester (esterification rate 80%): 25 parts by mass (C) Component: Mixed solvent of PGMEA / PGME = 60/40: 400 parts by mass

<Abbreviations and chemical structures of constituents of alkali-soluble resins>
In Table 1, the abbreviations of the polymerizable monomers used and their chemical structures are as follows.

A1-1: 4-hydroxyphenyl methacrylate A1-2: methacrylic acid A2-1: methyl methacrylate A2-2: butyl methacrylate A2-3: benzyl methacrylate A4-1: glycidyl methacrylate

A2-4:

A3-1:

[Pattern formation method]
The photosensitive resin composition is applied onto a glass substrate (manufactured by Dow Corning: 0.7 mm × 150 mm (thickness × diameter)) with a spinner so as to have a film thickness of 2 μm, and then 110 ° C. on a hot plate. And dried for 2 minutes to obtain a coating film. This coating film was exposed using a mirror projection aligner (trade name: MPA-600FA, manufactured by Canon Inc.) through a positive mask pattern of 2 μm line pattern / 2 μm space pattern. Next, development was performed by immersion for 1 minute in a 2.38 mass% aqueous solution (developer) of tetramethylammonium hydroxide, and unnecessary portions were removed through rinsing with pure water to obtain a pattern.

[Resolution evaluation method]
The evaluation of the resolution was carried out with ○ indicating that the 2 μm line pattern was resolved and × not being resolved.

[Dielectric constant evaluation method]
Dielectric constants of the interlayer insulating films formed from the photosensitive resin compositions of the above Examples and Comparative Examples were evaluated by the following procedure. First, a part of the formed interlayer insulating film is cut out from the substrate, aluminum is vapor-deposited on the cut out interlayer insulating film, and the obtained insulation is obtained using a measuring instrument (product name “SSM495”, manufactured by Solid State Measurement). The dielectric constant (0.9216 MHz) of the film was measured.

Table 2 shows the results of resolution and dielectric constant evaluation.

  The acrylic 7 used in Comparative Example 1 is obtained by replacing the structural unit A2 used in the acrylic 8 of Comparative Example 2 with an alicyclic epoxy group-containing unit A3. In the acrylic 7, the dielectric constant of the interlayer insulating film of the comparative example 1 that was unexpectedly formed was smaller than that of the comparative example 2, although the total amount of the epoxy groups increased compared to the acrylic 8. . Examples 1 to 6, which are examples according to the present invention that optimize the amount of the unit A3 in the acrylic 7 and further reduce the amount of epoxy groups in the entire copolymer, are all of the comparative examples. It has a lower electrical property and has preferable electrical characteristics as an interlayer insulating film of a package substrate.

Claims (5)

A photosensitive resin composition for an interlayer insulating film containing an alkali-soluble resin (A), a photosensitive agent (B), and an organic solvent (C),
The alkali-soluble resin (A) includes a structural unit (A1) represented by the following general formula (a-1), a structural unit (A2) represented by the following general formula (a-2), and an alicyclic group. A photosensitive resin composition for an interlayer insulating film, comprising a copolymer having an epoxy group-containing unit (A3) in its structure.

[In the general formula, R ⁰ represents a hydrogen atom or a methyl group, and Ra represents a hydrogen atom or an organic group having a hydroxyl group. ]

[In the above general formula, R ¹ represents a hydrogen atom or a methyl group, and Rb represents a hydrocarbon group. ] The photosensitive resin composition for interlayer insulation films of Claim 1 with which the said structural unit (A1) is represented by the following general formula (a-1-1).

[In the general formula, R ⁰ represents a hydrogen atom or a methyl group, R ² represents a single bond or an alkylene group having 1 to 5 carbon atoms, R ³ represents an alkyl group having 1 to 5 carbon atoms, and a represents The integer of 1-5 is represented, b represents the integer of 0 or 1-4, and a + b is 5 or less. In the case where R ³ is present 2 or more, these R ³ may be the same or may be different from each other. ]   The photosensitive resin composition for interlayer insulation films according to claim 1 or 2, wherein the content ratio of the structural unit (A1) in the copolymer is 20 to 60 mol%.   The photosensitive resin composition for interlayer insulation films according to claim 1 or 2, wherein the content ratio of the alicyclic epoxy group-containing unit (A3) in the copolymer is 10 to 40 mol%.   The photosensitive resin composition for an interlayer insulating film according to claim 1, wherein the photosensitive agent (B) is a quinonediazide group-containing compound.