JP2020056847A - Photosensitive resin composition, dry film, cured product, and electronic component - Google Patents

Abstract

To provide a photosensitive resin composition from which a cured film, which allows formation of a self-supporting film, and has excellent chemical resistance, excellent heat, and dielectric characteristics even when cured at a low-temperature around 220°C, can be obtained, the photosensitive resin composition being suitably used for an insulating film for rewiring, a dry film having a resin layer obtained from the composition, a cured product of the composition or the resin layer of the dry film, and an electronic component having the cured product.SOLUTION: The photosensitive resin composition or the like is characterized by including a polybenzoxazole precursor (A), a photosensitizer (B), a bifunctional or higher functional epoxy compound (C), and a heat acid generator (D).SELECTED DRAWING: None

Description

  The present invention relates to a photosensitive resin composition, a dry film, a cured product, and an electronic component.

  Conventionally, as an insulating material for rewiring in a semiconductor element, a resin composition containing a polybenzoxazole precursor (hereinafter, also referred to as a “PBO precursor”) as a main component has been used. The PBO precursor is heated at a high temperature (> 350 ° C.) to undergo a cyclization reaction to form a benzoxazole ring, which results in a rigid structure and an increase in packing density between molecules. According to the contained resin composition, a cured film having excellent mechanical properties such as chemical resistance, thermal properties and flexibility can be obtained.

  On the other hand, in recent years, a so-called molding-first type fan-out wafer-level package method has been developed in which a chip is sealed with a sealant and then rewiring is formed. Therefore, as an insulating material for rewiring used in such a method, a material that can be cured at a low temperature of about 220 ° C. is required from the viewpoint of heat resistance of a sealing material containing an epoxy resin as a main component.

  However, at such a low temperature, the resin composition containing the PBO precursor tends to crack in the cured film because the cyclization of the PBO precursor does not proceed sufficiently, and the resin composition has chemical resistance, thermal properties, and flexibility. There is a problem that various characteristics such as mechanical characteristics such as the above are also deteriorated.

  On the other hand, conventionally, in order to solve these problems, various approaches for adding a crosslinking agent such as an epoxy compound to a resin composition containing a PBO precursor have been proposed (for example, Patent Document 1).

JP 2014-111718 A

  However, when an epoxy compound is blended as a cross-linking agent, a cross-linking reaction enables the formation of a free-standing cured film (free-standing film) free of cracks even at the time of low-temperature curing, but the phenolic hydroxyl group of the PBO precursor and the epoxy compound of the epoxy group compound are used. In the formation of a crosslinked structure by the reaction of a group, a hydroxyl group is generated in the crosslinked structure, and there is a trade-off problem that the dielectric properties are deteriorated. There is also room for improvement in chemical resistance and thermal properties.

Therefore, a main object of the present invention is to form a self-supporting film even when curing is performed at a low temperature of about 220 ° C., and to obtain an insulating film having excellent chemical resistance, thermal properties, and dielectric properties. Another object of the present invention is to provide a photosensitive resin composition suitable for use as an insulating film for rewiring.
Another object of the present invention is to provide a dry film having a resin layer obtained from the composition, a cured product of the composition or the resin layer of the dry film, and an electronic component having the cured product. .

  The present inventors have intensively studied to achieve the above object. As a result, the present inventors have found that a photosensitive resin composition containing a PBO precursor can solve the above-mentioned problems by using a bifunctional or more epoxy compound as a cross-linking agent and combining it with a thermal acid generator in combination. The invention has been completed.

  That is, the photosensitive resin composition of the present invention contains (A) a polybenzoxazole precursor, (B) a photosensitizer, (C) a bifunctional or higher functional epoxy compound, and (D) a thermal acid generator. It is a feature.

  In the photosensitive resin composition of the present invention, the thermal acid generator (D) is preferably a sulfonic acid ester compound.

  In the photosensitive resin composition of the present invention, it is preferable that the (C) bifunctional or higher epoxy compound has a naphthalene structure.

  The dry film of the present invention is characterized by having a resin layer obtained by applying and drying the photosensitive resin composition on a film.

  The cured product of the present invention is obtained by curing the photosensitive resin composition or the resin layer of the dry film.

  An electronic component according to the present invention includes the cured product.

  According to the present invention, even when curing is performed at a low temperature of about 220 ° C., a self-supporting film can be formed, and a cured film having excellent chemical resistance, thermal properties, and dielectric properties can be obtained. A photosensitive resin composition suitable for use as an insulating film for wiring can be provided. Further, according to the present invention, a dry film having a resin layer obtained from the composition, a cured product of the composition or the resin layer of the dry film, and an electronic component having the cured product can be provided.

  Hereinafter, the components contained in the photosensitive resin composition of the present invention will be described in detail.

[(A) Polybenzoxazole precursor]
The photosensitive resin composition of the present invention contains (A) a polybenzoxazole precursor. (A) The method for synthesizing the polybenzoxazole precursor is not particularly limited, and may be a known method. For example, it can be obtained by reacting a dihydroxydiamine as an amine component with a dicarboxylic acid component such as dicarboxylic acid dichloride, dicarboxylic acid, or dicarboxylic acid ester as an acid component.

（式中、Ｘは４価の有機基を示し、Ｙは２価の有機基を示す。ｎは２以上の整数であり、好ましくは１０〜２００、より好ましくは２０〜７０である。） (A) The polybenzoxazole precursor is preferably a polyhydroxyamide, and more preferably a polyhydroxyamide having a repeating structure represented by the following general formula (1).

(In the formula, X represents a tetravalent organic group, and Y represents a divalent organic group. N is an integer of 2 or more, preferably 10 to 200, and more preferably 20 to 70.)

  (A) When synthesizing the polybenzoxazole precursor by the above synthesis method, in the above general formula (1), X is a residue of the above dihydroxydiamine, and Y is a residue of the above dicarboxylic acid component. is there.

  Examples of the dihydroxydiamine having the above-mentioned repeating structure include 3,3′-diamino-4,4′-dihydroxybiphenyl, 4,4′-diamino-3,3′-dihydroxybiphenyl, and bis (3-amino-4-hydroxy Phenyl) propane, bis (4-amino-3-hydroxyphenyl) propane, bis (3-amino-4-hydroxyphenyl) sulfone, bis (4-amino-3-hydroxyphenyl) sulfone, 2,2-bis (3 -Amino-4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis (4-amino-3-hydroxyphenyl) -1,1,1,3,3 , 3-hexafluoropropane and the like. Among them, 2,2-bis (3-amino-4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane is preferred.

  Examples of the dicarboxylic acid component having the above repeating structure include isophthalic acid, terephthalic acid, 5-tert-butylisophthalic acid, 5-bromoisophthalic acid, 5-fluoroisophthalic acid, 5-chloroisophthalic acid, and 2,6-naphthalenedicarboxylic acid. 4,4'-dicarboxybiphenyl, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxytetraphenylsilane, bis (4-carboxyphenyl) sulfone, 2,2-bis (p-carboxyphenyl) Dicarboxylic acid having an aromatic ring such as propane, 2,2-bis (4-carboxyphenyl) -1,1,1,3,3,3-hexafluoropropane, oxalic acid, malonic acid, succinic acid, 1,2 -Cyclobutanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclopentanedica It includes aliphatic dicarboxylic acids such as carbon acid. Among them, 4,4'-dicarboxydiphenyl ether is preferred.

  In the general formula (1), the tetravalent organic group represented by X may be either an aliphatic group or an aromatic group, but is preferably an aromatic group, and two hydroxy groups and two amino groups are located at ortho positions. More preferably, it is located on an aromatic ring. The tetravalent aromatic group preferably has 6 to 30 carbon atoms, more preferably 6 to 24 carbon atoms. Specific examples of the tetravalent aromatic group include, but are not limited to, the following groups.A known aromatic group that can be included in the polybenzoxazole precursor is selected according to the application. do it.

The tetravalent aromatic group is preferably a group shown below among the above aromatic groups.

  In the general formula (1), the divalent organic group represented by Y may be either an aliphatic group or an aromatic group, but is preferably an aromatic group. More preferably, it is bonded to The divalent aromatic group preferably has 6 to 30 carbon atoms, more preferably 6 to 24 carbon atoms. Specific examples of the divalent aromatic group include the following groups, but are not limited thereto, and any known aromatic group contained in the polybenzoxazole precursor may be selected according to the application. I just need.

（式中、Ａは単結合、−ＣＨ_２−、−Ｏ−、−ＣＯ−、−Ｓ−、−ＳＯ_２−、−ＮＨＣＯ−、−Ｃ（ＣＦ_３）_２−、−Ｃ（ＣＨ_３）_２−からなる群から選択される２価の基を表す。）

(In the formula, A is a single _{bond, -CH 2 -, - O -} , - CO -, - S -, - SO 2 -, - NHCO -, - C (CF 3) 2 -, - C (CH 3) ₂ - represents a divalent radical selected from the group consisting of).

The divalent organic group is preferably a group shown below among the aromatic groups.

  (A) The polybenzoxazole precursor may contain two or more kinds of the above-mentioned polyhydroxyamide repeating structures. Further, (A) the polybenzoxazole precursor may include a structure other than the above-described polyhydroxyamide repeating structure, and may include, for example, a polyamic acid repeating structure or a benzoxazole structure.

  (A) The number average molecular weight (Mn) of the polybenzoxazole precursor is preferably from 1,000 to 100,000, and more preferably from 5,000 to 50,000. Here, the number average molecular weight is a value measured by gel permeation chromatography (GPC) and converted into standard polystyrene. The weight average molecular weight (Mw) of (A) the polybenzoxazole precursor is preferably from 5,000 to 200,000, and more preferably from 10,000 to 100,000. Here, the weight average molecular weight is a value measured by GPC and converted into standard polystyrene. Mw / Mn is preferably from 1 to 5, more preferably from 1 to 3.

  As the polybenzoxazole precursor (A), one type may be used alone, or two or more types may be used in combination.

[(B) Photosensitizer]
The photosensitive resin composition of the present invention contains (B) a photosensitive agent. (B) The photosensitive agent is not particularly limited, and a photoacid generator or a photobase generator can be used. The photoacid generator is a compound that generates an acid by irradiation with light such as ultraviolet light or visible light, and the photobase generator changes the molecular structure or cleaves the molecule by the same light irradiation. A compound that produces more than one basic substance. In the present invention, a photoacid generator can be suitably used as the photosensitive agent (B).

  Examples of the photoacid generator include naphthoquinonediazide compounds, diarylsulfonium salts, triarylsulfonium salts, dialkylphenacylsulfonium salts, diaryliodonium salts, aryldiazonium salts, aromatic tetracarboxylic acid esters, aromatic sulfonic acid esters, and nitrobenzyl esters , Aromatic N-oxyimide sulfonate, aromatic sulfamide, benzoquinonediazosulfonic acid ester and the like. The photoacid generator is preferably a dissolution inhibitor. Among them, a naphthoquinonediazide compound is preferred.

  As the naphthoquinonediazide compound, specifically, for example, a naphthoquinonediazide adduct of tris (4-hydroxyphenyl) -1-ethyl-4-isopropylbenzene (for example, TS533, TS567, TS583, and TS593 manufactured by Sanbo Chemical Laboratory Co., Ltd.) ), A naphthoquinonediazide adduct of tetrahydroxybenzophenone (for example, BS550, BS570, BS599 manufactured by Sanpo Chemical Laboratory), or 4- {4- [1,1-bis (4-hydroxyphenyl) ethyl] -α , Α-dimethylbenzyl} phenol naphthoquinonediazide adduct (for example, TKF-428 and TKF-528 manufactured by Sanbo Chemical Laboratory Co., Ltd.) and the like can be used.

  The photobase generator may be an ionic photobase generator or a non-ionic photobase generator, but the ionic photobase generator has higher sensitivity of the composition and is suitable for forming a pattern film. It is preferable because it becomes advantageous. Examples of the basic substance include a secondary amine and a tertiary amine.

  Examples of the ionic photobase generator include salts of aromatic component-containing carboxylic acids and tertiary amines, and ionic PBGs WPBG-082, WPBG-167, WPBG-168, and WPBG- manufactured by Wako Pure Chemical Industries, Ltd. 266, WPBG-300 or the like can be used.

  Non-ionic photobase generators include, for example, α-aminoacetophenone compounds, oxime ester compounds, N-formylated aromatic amino groups, N-acylated aromatic amino groups, nitrobenzyl carbamate groups, and alkoxyoxybenzyl groups. Compounds having a substituent such as a carbamate group are exemplified. As other photobase generators, WPBG-018 (trade name: 9-anthrylmethyl N, N'-diethylcarbamate) and WPBG-027 (trade name: (E) -1- [3- (2) manufactured by Wako Pure Chemical Industries, Ltd.] -Hydroxyphenyl) -2-propenoyl] piperidine), WPBG-140 (trade name: 1- (anthraquinon-2-yl) ethyl imidazolecarboxylate), WPBG-165 and the like can also be used.

  As the photosensitive agent (B), one type may be used alone, or two or more types may be used in combination. The amount of the photosensitive agent (B) is preferably 3 to 30 parts by mass with respect to 100 parts by mass of the nonvolatile component of the polybenzoxazole precursor (A).

[(C) Bifunctional or higher functional epoxy compound]
The photosensitive resin composition of the present invention contains (C) a bifunctional or higher functional epoxy compound as a crosslinking agent. (C) The bifunctional or higher epoxy compound thermally reacts with the hydroxyl group of the polybenzoxazole precursor to form a crosslinked structure. (C) The number of functional groups of the epoxy compound having two or more functional groups is preferably 2 to 4.

  (C) Bifunctional or higher functional epoxy compounds include epoxidized vegetable oil; bisphenol A type epoxy compound; hydroquinone type epoxy compound; bisphenol type epoxy compound; thioether type epoxy compound; brominated epoxy compound; novolak type epoxy compound; Epoxy compound; bisphenol F type epoxy compound; hydrogenated bisphenol A type epoxy compound; glycidylamine type epoxy compound; hydantoin type epoxy compound; alicyclic epoxy compound; trihydroxyphenylmethane type epoxy compound; bixylenol type or biphenol type epoxy compound Or a mixture thereof; bisphenol S type epoxy compound; bisphenol A novolak type epoxy compound; tetraphenylolethane type epoxy compound Heterocyclic epoxy compound; Diglycidyl phthalate compound; Tetraglycidyl xylenoyl ethane compound; Epoxy compound having a naphthalene skeleton; Epoxy compound having a dicyclopentadiene skeleton; Glycidyl methacrylate copolymer-based epoxy compound; Glycidyl methacrylate copolymerized epoxy compounds; epoxy-modified polybutadiene rubber derivatives; CTBN-modified epoxy compounds, and the like, but are not limited thereto. (C) Bifunctional or higher functional epoxy compounds can be used alone or in combination of two or more.

  (C) Among the bifunctional or higher functional epoxy compounds, a bifunctional or higher functional epoxy compound having a naphthalene skeleton is preferable. Not only can an insulating film excellent in flexibility and chemical resistance be obtained, but also CTE can be reduced in a trade-off relationship with flexibility, and warpage and cracking of the insulating film can be suppressed. Further, bisphenol A type epoxy compounds can also be suitably used from the viewpoint of flexibility.

  The bifunctional or higher epoxy compound having a naphthalene skeleton is not particularly limited as long as it has a naphthalene skeleton and has two or more epoxy groups. For example, 1,2-diglycidylnaphthalene, 1,5-diglycidyl Naphthalene, 1,6-diglycidylnaphthalene, 1,7-diglycidylnaphthalene, 2,7-diglycidylnaphthalene, triglycidylnaphthalene, and 1,2,5,6-tetraglycidylnaphthalene, naphthol aralkyl epoxy resin, naphthalene Modified naphthalene type epoxy resins such as skeleton modified cresol novolak type epoxy resin, methoxy naphthalene modified cresol novolak type epoxy resin, naphthylene ether type epoxy resin, and methoxy naphthalene dimethylene type epoxy resin.

  Commercially available products include DIC Corporation's HP-4032D, HP-4700, HP-4770, HP-5000, HP-6000, HP-4710, Nippon Kayaku's NC-7000L, NC-7300L, and the like.

  The bifunctional or higher functional epoxy compound having a naphthalene skeleton may or may not have a soft chain in the structure, but may have a soft chain without having a soft chain. For example, it is not necessary to have a linear structure having 5 to 10 atoms, and more preferably 3 to 5 atoms between epoxy groups, since the property can be improved.

  (C) The epoxy equivalent of the bifunctional or higher functional epoxy compound is preferably from 100 to 500 g / eq, more preferably from 100 to 300 g / eq.

  (C) The compounding amount of the bifunctional or higher epoxy compound is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 30 parts by mass, based on 100 parts by mass of the nonvolatile component of (A) the polybenzoxazole precursor. Department. By setting the content in such a range, it is possible to maintain an appropriate crosslinking density for the (A) polybenzoxazole precursor.

(Other crosslinking agents)
The photosensitive resin composition of the present invention may contain a crosslinking agent other than (C) a bifunctional or higher functional epoxy compound. In the present specification, the other crosslinking agent is preferably a compound that reacts with the phenolic hydroxyl group of the polybenzoxazole precursor to form a crosslinked structure, in addition to the above epoxy compound. Here, the functional group that reacts with the phenolic hydroxyl group of the polybenzoxazole precursor includes a cyclic ether group such as an epoxy group, a cyclic thioether group such as an episulfide group, an alkylene group having 1 to 12 carbon atoms such as a methylol group, and a hydroxyl group. An alcoholic hydroxyl group to which a group is bonded is exemplified.

（式中、Ｒ^２１Ａ、Ｒ^２２Ａ、Ｒ^２３Ａ、Ｒ^２４Ａ、Ｒ^２５ＡおよびＲ^２６Ａはそれぞれ独立に炭素数１〜３のアルキレン基であることが好ましい。Ｒ^２１Ｂ、Ｒ^２２Ｂ、Ｒ^２３Ｂ、Ｒ^２４Ｂ、Ｒ^２５ＢおよびＲ^２６Ｂはそれぞれ独立に水素原子、または、炭素数１〜３のアルキル基であることが好ましい。） As other crosslinking agents, among others, a crosslinking agent having a triazine ring structure is preferable, and in the present invention, the elongation of the cured product can be further improved. The crosslinking agent having a triazine ring structure is not particularly limited, but is preferably a crosslinking agent represented by the following general formula (2).

(In the formula, R ^21A , R ^22A , R ^23A , R ^24A , R ^25A and R ^26A are each independently preferably an alkylene group having 1 to 3 carbon atoms. R ^21B , R ^22B , R ^23B , R ^24B , R ^25B and R ^26B are each independently preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

In the general formula (2), each of R ^21A , R ^22A , R ^23A , R ^24A , R ^25A and R ^26A is more preferably a methylene group. More preferably, R ^21B , R ^22B , R ^23B , R ^24B , R ^25B and R ^26B are each independently a methyl group or a hydrogen atom.

  As the other crosslinking agents, one type may be used alone, or two or more types may be used in combination. The amount of the other crosslinking agent is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the non-volatile component of the polybenzoxazole precursor so that the developability is not impaired by the crosslinking. Moreover, 0.1-20 mass parts is more preferable.

((D) thermal acid generator))
The photosensitive resin composition of the present invention contains (D) a thermal acid generator. In the present invention, (A) the phenolic hydroxyl group of the polybenzoxazole precursor and (C) the epoxy group of the difunctional or higher functional epoxy compound are considered to react to form a crosslinked structure. In addition, since a dielectric property is deteriorated due to the generation of a hydroxyl group in the crosslinked structure, there is room for improvement as an insulating material. Although the detailed mechanism is not clear, the addition of (D) a thermal acid generator in the present invention promotes the cyclization reaction at a low temperature by acting as a catalyst for the cyclization reaction of (A) the polybenzoxazole precursor. The dielectric properties are improved by reducing the number of hydroxyl groups in the crosslinked structure, and a cured product having more excellent chemical resistance and heat resistance can be obtained by promoting the cyclization reaction. (D) As the thermal acid generator, one type may be used alone, or two or more types may be used in combination.

  (D) The thermal acid generator is not particularly limited as long as the acid is generated by heat. Examples of the generated acid include, for example, sulfonic acid, carboxylic acid, acetic acid, hydrochloric acid, nitric acid, bromic acid, and iodic acid.From the viewpoint of cyclization efficiency, strong acids are preferable, and benzenesulfonic acid and p-toluene are preferable. Sulfonic acids such as arylsulfonic acids such as sulfonic acid, perfluoroalkylsulfonic acids such as trifluoromethanesulfonic acid, nonafluorobutanesulfonic acid and camphorsulfonic acid, and alkylsulfonic acids such as methanesulfonic acid, ethanesulfonic acid and butanesulfonic acid. Is preferred. These acids are added to the photosensitive resin composition as a thermal acid generator, for example, a salt as an onium salt or a compound latentified by a covalent bond such as imidosulfonate.

  (D) Specific examples of the thermal acid generator include a sulfonic acid ester compound, a sulfonimide compound, a sulfonium salt, 2-sulfobenzoic anhydride, p-toluenesulfonic anhydride, a benzothiazolium salt, an ammonium salt, Examples include phosphonium salts and sulfonates. Among these, a sulfonic acid ester compound and a sulfonic acid salt are preferable. The thermal acid generator is preferably a compound that generates a strong acid (having an acid dissociation constant pKa in water of 0 or less) by heat.

  Examples of the sulfonic acid ester compound include ethyl methanesulfonate, methyl methanesulfonate, 2-methoxyethyl methanesulfonate, 2-isopropoxyethyl methanesulfonate, cyclohexyl 4-methylbenzenesulfonate, (1R, 2S, 5R)- 5-methyl-2- (propan-2-yl) cyclohexyl 4-methylbenzenesulfonic acid, phenyl p-toluenesulfonate, ethyl p-toluenesulfonate, methyl p-toluenesulfonate, 2-phenyl p-toluenesulfonate Ethyl, n-propyl p-toluenesulfonate, n-butyl p-toluenesulfonate, t-butyl p-toluenesulfonate, n-hexyl p-toluenesulfonate, n-heptyl p-toluenesulfonate, p-toluene N-octyl sulfonate, p-tolue 2-methoxyethyl sulfonate, propargyl p-toluenesulfonate, 3-butynyl p-toluenesulfonate, ethyl trifluoromethanesulfonate, n-butyl trifluoromethanesulfonate, ethyl perfluorobutanesulfonate, methyl perfluorobutanesulfonate Benzyl (4-hydroxyphenyl) methylsulfonium hexafluoroantimonate, benzyl (4-hydroxyphenyl) methylsulfonium hexafluorophosphate, trimethylsulfonium methylsulfate, tri-p-sulfonium trifluoromethanesulfonate, trimethylsulfonium trifluoromethanesulfonate, Pyridinium-p-toluenesulfonate, ethyl perfluorooctanesulfonate, 1,4-butanesultone, 2 , 4-butane sultone, 1,3-propane sultone, phenol red, bromocresol green, bromocresol purple and the like.

  As the sulfonic acid ester compound, a compound represented by the following general formula (3) is preferable.

（一般式（３）中、Ｒ^３１は、水素原子またはアルキル基を表し、Ｒ^３２は、水素原子または有機基を表す。）

(In the general formula (3), R ³¹ represents a hydrogen atom or an alkyl group, and R ³² represents a hydrogen atom or an organic group.)

The alkyl group which R ³¹ can have may be straight-chain or branched. Further, the number of carbon atoms is preferably 1 to 10, more preferably 1 to 6.

The organic group R ³² can be taken, which may be branched may be linear or may have a cyclic structure. The number of carbon atoms is preferably from 1 to 16, more preferably from 1 to 11.

  As the sulfonate, a compound represented by the following general formula (4) is preferable.

（一般式（４）中、Ｒ^４１は水素原子またはアルキル基を表し、Ｒ^４２、Ｒ^４３はそれぞれ独立に水素原子または有機基を表す。Ｒ^４２とＲ^４３は結合して環を形成してもよい。）

(In the general formula (4), R ⁴¹ represents a hydrogen atom or an alkyl group, and R ⁴² and R ⁴³ each independently represent a hydrogen atom or an organic group. R ⁴² and R ⁴³ are bonded to form a ring. May be.)

The alkyl group which R ⁴¹ can take may be straight-chain or branched. Further, the number of carbon atoms is preferably 1 to 10, more preferably 1 to 6.

The organic group which R ⁴² and R ⁴³ can take may be straight-chain or branched.

  In the general formulas (3) and (4) and the general formulas (5) and (6) described later, the organic group is a group containing a carbon atom. Examples of the organic group include an alkyl group having 1 to 12 carbon atoms, which may be linear or branched.

  (D) Among the thermal acid generators, a thermal acid generator that generates an acid at 120 to 220 ° C is preferable. In the case of a thermal acid generator that generates an acid at a temperature of 120 ° C. or higher, the reaction hardly proceeds during prebaking, and a development residue hardly occurs. Further, a thermal acid generator that generates an acid at 150 to 220 ° C. is preferable. The generation of acid can be confirmed at the temperature at which the weight is reduced by TG-DTA.

  (D) The mixing amount of the thermal acid generator is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the nonvolatile component of the polybenzoxazole precursor. More preferably, it is 1 to 3 parts by mass.

(Sensitizers, adhesives, and other components)
The photosensitive resin composition of the present invention includes, within a range not impairing the effects of the present invention, a known sensitizer for further improving the photosensitivity, and a silane coupling agent for improving the adhesion to the substrate. Can also be blended. Further, in order to impart processing characteristics and various functions to the photosensitive resin composition of the present invention, various other organic or inorganic low-molecular or high-molecular compounds may be blended. For example, a surfactant, a leveling agent, a plasticizer, fine particles, and the like can be used. The fine particles include organic fine particles such as polystyrene and polytetrafluoroethylene, and inorganic fine particles such as silica, carbon, and layered silicate. Further, various colorants, fibers and the like may be blended in the photosensitive resin composition of the present invention.

(solvent)
The solvent used in the photosensitive resin composition of the present invention includes (A) a polybenzoxazole precursor, (B) a photosensitizer, (C) a difunctional or higher functional epoxy compound, (D) a thermal acid generator, and others. Is not particularly limited as long as the additive dissolves the additive. Examples include N, N′-dimethylformamide, N-methylpyrrolidone, N-ethyl-2-pyrrolidone, N, N′-dimethylacetamide, diethylene glycol dimethyl ether, cyclopentanone, γ-butyrolactone, α-acetyl-γ- Examples include butyrolactone, tetramethylurea, 1,3-dimethyl-2-imidazolinone, N-cyclohexyl-2-pyrrolidone, dimethylsulfoxide, hexamethylphosphoramide, pyridine, γ-butyrolactone, and diethylene glycol monomethyl ether. These may be used alone or in combination of two or more. The amount of the solvent to be used can be appropriately determined according to the coating film thickness and the viscosity. For example, it can be used in the range of 50 to 9000 parts by mass based on 100 parts by mass of the polybenzoxazole precursor (A).

  The photosensitive resin composition of the present invention is preferably of a positive type.

[Dry film]
The dry film of the present invention has a resin layer obtained by applying the photosensitive resin composition of the present invention to a film (for example, a support (carrier) film) and then drying. This resin layer is used after being laminated so as to be in contact with the base material.

  The dry film of the present invention is formed by uniformly applying the photosensitive resin composition of the present invention to the film by an appropriate method such as a blade coater, a lip coater, a comma coater, a film coater, and the like, and drying to form the above-described resin layer. Preferably, it can be manufactured by laminating a film (a so-called protective (cover) film) thereon. The same film material may be used for the protective film and the support film, or different films may be used.

In the dry film of the present invention, as the film material of the support film and the protective film, any of those known as materials used for dry films can be used.
As the support film, for example, a thermoplastic film such as a polyester film such as polyethylene terephthalate having a thickness of 2 to 150 μm is used.
As the protective film, a polyethylene film, a polypropylene film, or the like can be used, but a film having lower adhesive strength to the resin layer than the supporting film is preferable.

  The thickness of the resin layer on the dry film of the present invention is preferably 100 μm or less, more preferably 5 to 50 μm.

[Cured product]
The cured product of the present invention is obtained by curing the photosensitive resin composition of the present invention in a predetermined step. The pattern film as the cured product may be manufactured by a known and commonly used manufacturing method. For example, in the case of (B) a positive photosensitive resin composition containing a photoacid generator as a photosensitive agent, the following steps are performed. To manufacture.

First, as step 1, a coating film is obtained by applying and drying a photosensitive resin composition on a substrate, or by transferring a resin layer from a dry film onto a substrate. As a method of applying the photosensitive resin composition on the substrate, a method conventionally used for applying the photosensitive resin composition, for example, a spin coater, a bar coater, a blade coater, a curtain coater, a screen printing machine, and the like , A spray coating method using a spray coater, and an ink jet method. As a method for drying the coating film, methods such as air drying, heating drying using an oven or a hot plate, and vacuum drying are used. It is desirable that the drying of the coating film is performed under such conditions that the cyclization of the polybenzoxazole precursor in the photosensitive resin composition does not occur. Specifically, natural drying, blast drying, or heat drying can be performed at 70 to 140 ° C. for 1 to 30 minutes. Preferably, drying is performed on a hot plate for 1 to 20 minutes. Vacuum drying is also possible. In this case, the drying can be performed at room temperature for 20 minutes to 1 hour.
The substrate on which the coating film of the photosensitive resin composition is formed is not particularly limited, and can be widely applied to semiconductor substrates such as silicon wafers, wiring substrates, various resins, metals, and the like.

  Next, as step 2, the coating film is exposed through a photomask having a pattern or directly. An exposure light having a wavelength capable of activating a photoacid generator (B) as a photosensitive agent is used. Specifically, the exposure light preferably has a maximum wavelength in the range of 350 to 440 nm. As described above, the photosensitivity can be adjusted by appropriately adding a sensitizer. As the exposure device, a contact aligner, a mirror projection, a stepper, a laser direct exposure device, or the like can be used.

  Next, as step 3, the coating film is treated with a developer. This makes it possible to form a pattern film of the photosensitive resin composition of the present invention by removing the exposed portions in the coating film.

  As a method used for development, any method can be selected from conventionally known methods for developing a photoresist, for example, a rotary spray method, a paddle method, an immersion method involving ultrasonic treatment, and the like. Examples of the developer include inorganic alkalis such as sodium hydroxide, sodium carbonate, sodium silicate, and aqueous ammonia; organic amines such as ethylamine, diethylamine, triethylamine, and triethanolamine; tetramethylammonium hydroxide; and tetrabutylammonium hydroxide. And aqueous solutions of quaternary ammonium salts. If necessary, an appropriate amount of a water-soluble organic solvent such as methanol, ethanol, or isopropyl alcohol or a surfactant may be added to these. Thereafter, if necessary, the coating film is washed with a rinsing liquid to obtain a pattern film. As the rinsing liquid, distilled water, methanol, ethanol, isopropyl alcohol and the like can be used alone or in combination. Further, the above-mentioned solvent may be used as a developer.

  Then, as a step 4, the pattern film is heated to obtain a cured coating film (cured product). By this heating, the polybenzoxazole precursor is cyclized to obtain polybenzoxazole. The heating temperature is appropriately set so that the pattern film of the photosensitive resin composition can be cured. For example, heating is performed at 150 ° C. or more and less than 350 ° C. for about 5 to 120 minutes in an inert gas. A more preferable range of the heating temperature is 180 to 250 ° C. Since the photosensitive resin composition of the present invention contains (C) a bifunctional or higher functional epoxy compound and (D) a thermal acid generator, cyclization is promoted, and a heating temperature of less than 250 ° C. and further 220 ° C. or less is obtained. can do. The heating is performed by using, for example, a hot plate, an oven, and a temperature rising oven in which a temperature program can be set. As the atmosphere (gas) at this time, air may be used, or an inert gas such as nitrogen or argon may be used.

  The use of the photosensitive resin composition of the present invention is not particularly limited. For example, it is suitable as a coating material, a printing ink, or an adhesive, or a display device, a semiconductor device, an electronic component, an optical component, or a building material. Used. Specifically, as a material for forming a display device, a color filter, a film for a flexible display, a resist material, an alignment film, or the like can be used as a layer forming material or an image forming material. In addition, as a material for forming a semiconductor device, a resist material, a layer forming material such as a buffer coat film, or the like can be used. Furthermore, as a material for forming an electronic component, a sealing material or a layer forming material can be used for a printed wiring board, an interlayer insulating film, a wiring coating film, or the like. Furthermore, as a material for forming an optical component, a hologram, an optical waveguide, an optical circuit, an optical circuit component, an antireflection film, or the like can be used as an optical material or a layer forming material. Furthermore, as a building material, it can be used for a paint, a coating agent and the like.

  The photosensitive resin composition of the present invention is mainly used as a pattern forming material, and the pattern film formed thereby functions as a component that imparts heat resistance and insulation as a permanent film made of, for example, polybenzoxazole. In particular, surface protection films for semiconductor devices, display devices and light emitting devices, interlayer insulation films, insulation films for rewiring, protection films for flip-chip devices, protection films for devices having a bump structure, interlayer insulation for multilayer circuits It can be suitably used as a film, an insulating material for passive components, a protective film for a printed wiring board such as a solder resist or a coverlay film, and a liquid crystal alignment film. In particular, the photosensitive resin composition of the present invention is suitable as a material for forming a layer to be laminated, for example, an interlayer insulating film or an insulating film for rewiring, since the cured product has excellent chemical resistance.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples. In the following, “parts” and “%” are all based on mass unless otherwise specified.

(Synthesis of polybenzoxazole precursor (A1))
2,2-bis (3-amino-4-hydroxyphenyl) -1,1,1,3,3,3 was placed in a four-neck separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a nitrogen gas inlet. After dissolving 40.3 g (0.11 mol) of hexafluoropropane in 1500 g of N-methyl-2-pyrrolidone, 35.4 g (0.12 mol) of diphenyl ether-4,4′-dicarboxylic acid dichloride was added to the reaction system. The solution was added dropwise while cooling the temperature to 0 to 5 ° C.
After completion of the dropwise addition, the temperature of the reaction system was returned to room temperature, and the mixture was stirred for 6 hours. Thereafter, 1.8 g (0.1 mol) of pure water was added, and the mixture was further reacted at 40 ° C. for 1 hour. After the completion of the reaction, the reaction solution was dropped into 2000 g of pure water. The precipitate was collected by filtration, washed, and dried under vacuum to obtain an alkali-soluble polyhydroxyamide (A1) which is a polybenzoxazole precursor having a repeating structure shown below. The weight average molecular weight was 32,000, the number average molecular weight was 12,500, and the PDI was 2.56.

(Preparation of positive photosensitive resin composition)
The photoacid generator (B1), the epoxy compound (C1 to C3), and each component were blended at the ratio shown in Table 1 below with respect to 100 parts by mass of the polybenzoxazole precursor (A1) synthesized above. After that, γ-butyrolactone was added so that the content of the polymer was 30% by mass to obtain a varnish. In addition, each epoxy compound was blended so that the ratio of the epoxy group to the phenolic OH of the polybenzoxazole precursor (A1) was 5: 1.

(Evaluation of self-supporting membrane)
The varnish prepared above was spin-coated on a silicon wafer and heated at 110 ° C. for 3 minutes to form a coating film having a thickness of 40 μm. Thereafter, the coating film was heated in an inert gas oven under a nitrogen atmosphere at 120 ° C. for 10 minutes, and then heated at 4 ° C./min. And heated at 220 ° C. for 60 minutes to obtain a cured film. Next, using a PCT apparatus (HAST SYSTEM TPC-412MD manufactured by Espec Corp.), the cured film was peeled off at 121 ° C. and 100% RH for 60 minutes. Were not obtained, and were broken.

(Measurement of dielectric constant and dielectric loss tangent)
The dielectric loss tangent Df, which is a dielectric property, was measured according to the following method.
The varnish prepared above was spin-coated on a silicon wafer and heated at 110 ° C. for 3 minutes to form a coating film having a thickness of 40 μm. Thereafter, the coating film was heated in an inert gas oven under a nitrogen atmosphere at 120 ° C. for 10 minutes, and then heated at 4 ° C./min. And heated at 220 ° C. for 60 minutes to obtain a cured film. Next, using a PCT apparatus (HAST SYSTEM TPC-412MD manufactured by Espec Corporation), the cured film was peeled off under the conditions of 121 ° C., 100% RH and 60 minutes to obtain a free-standing film. The obtained cured film was used as a test piece and measured by a SPDR (Split Post Dielectric Resonator) resonator method. As a measuring instrument, a vector type network analyzer E5071C and SPDR resonator manufactured by Keysight Technology GK, and a calculation program used by QWED were used. The conditions were a frequency of 10 GHz and a measurement temperature of 25 ° C.
Evaluation of dielectric constant:
A: less than 3.0 B: 3.0 or more Evaluation of dielectric loss tangent:
A: less than 0.01 B: 0.01 or more and less than 0.015 C: 0.015 or more

(Chemical resistance test)
The varnish prepared above was spin-coated on a silicon wafer and heated at 110 ° C. for 3 minutes to form a coating film having a thickness of 40 μm. Thereafter, the coating film was heated in an inert gas oven under a nitrogen atmosphere at 120 ° C. for 10 minutes, and then heated at 4 ° C./min. And heated at 220 ° C. for 60 minutes to obtain a cured film. Each of the obtained samples was immersed in γ-butyrolactone (GBL) at 25 ° C. for 10 minutes, and the change before and after immersion was evaluated.
A: Crackless B: Film loss less than 1% C: Film loss 1% or more

(Measurement of 5% weight loss temperature)
TG-DTA measurement was performed on a free standing film obtained by heating at 220 ° C. for 60 minutes obtained in the above (measurement of dielectric constant and dielectric loss tangent), which was cut into 1 to 2 mm squares and 5 to 10 mg in a nitrogen atmosphere. 580 ° C.), and the temperature at which the weight change was 5% was measured.
A: 300 ° C or higher B: Less than 300 ° C

(Measurement of Tg)
DMA Dynamic Viscoelasticity Measurement The varnish prepared above was spin-coated on a silicon wafer and heated at 110 ° C. for 3 minutes to form a coating film having a thickness of 40 μm. Thereafter, the coating film was heated in an inert gas oven under a nitrogen atmosphere at 120 ° C. for 10 minutes, and then heated at 4 ° C./min. And heated at 220 ° C. for 60 minutes to obtain a cured film. Next, using a PCT apparatus (HAST SYSTEM TPC-412MD manufactured by Espec Corporation), the cured film was peeled off under the conditions of 121 ° C., 100% RH and 60 minutes to obtain a free-standing film. The cured film was cut into 20 mm × 5 mm with a stainless steel blade (blade thickness 0.25 mm) and measured with a dynamic viscoelasticity measuring device (G2 RSA, manufactured by TA Instruments). The measurement was performed in the temperature rising process from room temperature to 350 ° C., and was performed at a temperature rising rate of 5 ° C./min, a load of 0.5 N, a frequency of 1 Hz, and a distance between grips of 10 mm. The peak top of tan δ was defined as Tg.
A: Tg is 260 ° C. or more B: Tg is less than 260 ° C.

(Measurement of residual film ratio of unexposed area and dissolution rate of exposed area)
The varnish prepared above was applied on a silicon substrate subjected to copper sputtering using a spin coater. It was dried on a hot plate at 100 ° C. for 3 minutes to obtain a dried film of the photosensitive resin composition having a thickness of 10 μm. Using a high-pressure mercury lamp, the obtained dried film was irradiated with i-line of 800 mJ / cm ² through a mask in which a pattern was cut. After exposure, the resist film was developed with a 2.38% aqueous solution of tetramethylammonium hydroxide (TMAH) and rinsed with water to obtain a positive pattern.
The remaining film ratio (%) was calculated from the remaining film thickness of the unexposed portion when the remaining film of the exposed portion became 0, and evaluated according to the following criteria.
A: 90% or more and B: less than 90% Further, the dry film thickness (nm) / the time (sec) when the residual film of the exposed portion became 0 was calculated as the dissolution rate of the exposed portion.

<(B) Photosensitizer>
(B1) Naphthoquinonediazide compound (TKF-428 manufactured by Sanbo Chemical Laboratory)

（Ｃ２）ＨＰ４０３２Ｄ（ＤＩＣ社製）

（Ｃ３）ＨＰ４７００（ＤＩＣ社製）

<(C) Bifunctional or higher epoxy compound>
(C1) EPICLON860 (manufactured by DIC)

(C2) HP4032D (manufactured by DIC)

(C3) HP4700 (manufactured by DIC)

（Ｄ２）ＷＰＡＧ６９９（富士フィルム和光純薬工業社製）

<(D) Thermal acid generator>
(D1) WPAG618 (Fuji Film Wako Pure Chemical Industries, Ltd.)

(D2) WPAG699 (Fuji Film Wako Pure Chemical Industries, Ltd.)

<Organic solvent>
* 1: GBL (γ-butyrolactone)

From the results shown in the above table, the photosensitive resin composition of the present invention can form a self-supporting film, even when cured at a low temperature of about 220 ° C., and has chemical resistance, thermal properties, and It can be seen that a cured film having excellent dielectric properties can be obtained.

Claims (5)

  A photosensitive resin composition comprising (A) a polybenzoxazole precursor, (B) a photosensitive agent, (C) a difunctional or higher functional epoxy compound, and (D) a thermal acid generator.   The photosensitive resin composition according to claim 1, wherein the (D) thermal acid generator is a sulfonic acid ester compound.   A dry film comprising a resin layer obtained by applying and drying the photosensitive resin composition according to claim 1 or 2 on a film.   A cured product obtained by curing the photosensitive resin composition according to claim 1 or 2 or the resin layer of the dry film according to claim 3. An electronic component comprising the cured product according to claim 4.