JP2008270495A - Flexible printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin-film flexible printed wiring board, where microfabrication can be performed by photosensitive coverlay, the photosensitive coverlay is laminated as an insulation layer of a wiring pattern, warpage and shrinkage are small in curing, and electric insulating properties are excellent. <P>SOLUTION: In the flexible printed wiring board, a wiring pattern formed at least on one side is protected by a photosensitive coverlay layer. The flexible printed wiring board has an amount of warpage of not more than 2 mm. The photosensitive coverlay layer is composed of a curing film. After curing as a film, the curing film is obtained from a photosensitive resin composition having an elasticity of 10-1000 MPa at 25°C and a glass-transition temperature of 60-120°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, a photosensitive coverlay that protects a flexible printed wiring board on which a fine wiring pattern is formed is curable at low temperature, has a low elastic modulus, and is preferably used as an insulating material for electrical and electronic applications. Further, the present invention relates to a flexible printed wiring board that is obtained from a photosensitive resin composition that can be developed with an aqueous alkali solution and that is less warped and is thin and excellent in electrical insulation.

  In recent years, electronic devices such as mobile phones and digital video cameras have been improved in functionality, performance, size, and weight, and there has been a demand for downsizing and weight reduction of electronic components. For example, the demand for flexible printed wiring boards that are lightweight and flexible is increasing year by year for wiring boards on which electronic components are mounted, compared to rigid wiring boards.

  The flexible printed wiring board has a coverlay film laminated on the surface for the purpose of protecting the wiring pattern formed on the polyimide film.

  Conventionally, a coverlay film is obtained by applying an adhesive to a polyimide film, and has excellent various electrical characteristics and chemical resistance. However, in order to make it suitable for fine substrate wiring, the method of thermocompression bonding after punching the coverlay film by microfabrication is taken, but there is a limit to fine patterning and positional accuracy, and the wiring width is fine. Then, since it is difficult to completely fill the gaps between the circuits with an adhesive, a photosensitive cover lay is required for finer processing.

  On the other hand, as the liquid cover coat ink, a photosensitive cover coat ink (generally also referred to as a solder resist) mainly composed of an epoxy resin or the like is used, and since it has photosensitivity, it is excellent in fine workability. However, this ink has excellent electrical insulation reliability as an insulating material, but has poor mechanical properties such as flexibility and is difficult to use for a flexible circuit board. In particular, there is a problem that the film is warped when applied to one side of a flexible and flexible film base material such as a polyimide film used for flexible printed wiring boards.

In recent years, a liquid cover coat ink using a polyimide resin has been proposed. For example, a photosensitive resin composition containing a polyimide resin using siloxane diamine has been proposed (see, for example, Patent Documents 1 and 2). Moreover, the photosensitive resin composition which consists of a polyamic-acid solution which is a precursor of a polyimide is proposed (for example, refer patent documents 3-4). Furthermore, a photosensitive resin composition or a plasma etching resist using a terminal half-esterified imidosiloxane oligomer has been proposed (see, for example, Patent Documents 5 to 8).
JP 9-100350 A JP 2002-162740 A JP-A-2-50161 JP-A-2005-148611 JP 2000-212446 A JP 2001-89656 A JP 2001-125273 A JP 2001-215702 A

  However, in Patent Documents 1 to 3 above, the polyimide type and the polyamic acid type cover coat ink which is a precursor thereof have a high curing temperature, and the cured film has a high elastic modulus. When coated, there was a problem that the flexible printed wiring board was warped. Further, in Patent Document 4, in addition to the above problems, an acrylic resin is reacted with the side chain of the polyamic acid, and a high temperature (300 ° C. or higher) is required to remove the functional group. There was also a problem that it could not be used as an insulating protective film on the surface of the flexible printed wiring board.

  Moreover, when the terminal half-esterified imide siloxane oligomer described in Patent Documents 5 to 8 is used, the elastic modulus of the cured product of the terminal half-esterified imide siloxane oligomer is high, and warping occurs when applied to the surface of a flexible printed wiring board. It was a big problem.

  In view of the above situation, the problem of the present invention is that the photosensitive cover lay can be finely processed, and the photosensitive cover lay is laminated as an insulating layer of the wiring pattern. An object of the present invention is to provide a flexible printed wiring board having excellent insulation properties.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a flexible printed wiring board protected by the following photosensitive coverlay layer.

  That is, the present invention is a flexible printed wiring board in which a wiring pattern formed on at least one surface is protected by a photosensitive coverlay layer, wherein the flexible printed wiring board has a warpage amount of 2 mm or less, and the photosensitive coverlay. In a flexible printed wiring board, the layer is a cured film obtained from a photosensitive resin composition having an elastic modulus at 25 ° C. of 10 to 1000 MPa and a glass transition temperature of 60 to 120 ° C. after curing as a film. is there.

  The photosensitive coverlay layer contains at least (A) a terminal tetracarboxylic acid siloxane imide oligomer, (B) a diamino compound, (C) a photopolymerization initiator, and (D) a photosensitive resin. It is a flexible printed wiring board characterized by being a cured film obtained from the conductive resin composition.

  The flexible printed wiring board is characterized in that the photosensitive coverlay layer is a cured film obtained from a photosensitive coverlay ink obtained by dissolving a photosensitive resin composition in an organic solvent.

  The flexible printed wiring board of the present invention is a photosensitive coverlay that protects a flexible printed wiring board on which a fine wiring pattern is formed, is curable at a low temperature, has a low elastic modulus, and is an insulating material for electrical and electronic applications. It is a flexible printed wiring board which is a cured film obtained from a photosensitive resin composition developable with an alkaline aqueous solution, which can be suitably used as a thin film, and has a small warp and excellent electrical insulation. It is to provide a flexible printed wiring board.

  The configuration of the present invention is a flexible printed wiring board in which a wiring pattern formed on at least one surface is protected by a photosensitive coverlay layer, wherein the flexible printed wiring board has a warpage amount of 2 mm or less, and the photosensitive cover A flexible printed wiring board, wherein the lay layer is a cured film obtained from a photosensitive resin composition having an elastic modulus at 25 ° C. of 10 to 1000 MPa and a glass transition temperature of 60 to 120 ° C. after curing as a film. It is. When the elastic modulus of the film is low, the glass transition temperature tends to be low, and the electrical insulation is deteriorated accordingly, but surprisingly, when using a photosensitive coverlay made of the photosensitive resin composition, Although the elastic modulus at 25 ° C. is low after curing as a film and the warp of the flexible printed wiring board is small, the glass transition temperature is high, so that a flexible printed wiring board that is thin and excellent in electrical insulation can be provided. . Details will be described below.

<Flexible printed wiring board>
The flexible printed wiring board in the present invention is a wiring board in which a wiring pattern made of a conductive material such as copper is formed on the surface of a base film such as polyimide having excellent flexibility and insulation. In the present invention, those in which the wiring pattern is protected by a photosensitive coverlay layer are also referred to as a flexible printed wiring board as appropriate. In general, roll-to-roll a long base film with adhesive, coating, drying, copper foil laminating, adhesive curing, wiring pattern formation (resist coating, copper etching, resist stripping). Manufactured.

  Although the thickness of a base film is not specifically limited, Preferably it is 5-125 micrometers, More preferably, it is 10-75 micrometers, Most preferably, it is 12-50 micrometers. Setting the thickness within the above range is preferable because the film can be easily handled.

  The flexible printed wiring board has a wiring width of 100 μm or less and a spacing between wirings of 100 μm or less, more preferably a wiring width of 50 μm or less, a spacing between wirings of 50 μm or less, and particularly preferably a wiring width of 30 μm or less. The interval is preferably 30 μm or less because the mounting density can be improved and the flexible printed wiring board can be reduced in weight and size.

<Photosensitive coverlay>
In the present invention, the photosensitive cover lay can be directly laminated on a flexible printed wiring board on which a wiring pattern is formed without the need for an adhesive layer, exposed with a photomask, and an alkaline aqueous solution. It is a photosensitive resin composition that can be finely processed by being developed and used as an insulating film for protecting a wiring pattern formed on a flexible printed wiring board after heat curing. The photosensitive cover lay is not particularly limited, but preferably, the photosensitive cover lay has a glass transition temperature of 60 to 120 ° C. and an elastic modulus at 25 ° C. of 10 to 1000 MPa after curing as a film. It is a cured film obtained from the resin composition. The range of the elastic modulus is more preferably 50 to 800 MPa, and particularly preferably 100 to 500 MPa. When the photosensitive cover lay has an elastic modulus after being cured within the above range as a film, it is preferable because warpage of the obtained flexible printed wiring board can be reduced. Moreover, the range of glass transition temperature becomes like this. More preferably, it is 70-110 degreeC, Most preferably, it is 80-100 degreeC. Since the photosensitive coverlay has a glass transition temperature after being cured as a film within the above range, even a thin film can exhibit excellent electrical insulation, which is preferable. The photosensitive coverlay layer contains at least (A) a terminal tetracarboxylic acid siloxane imide oligomer, (B) a diamino compound, (C) a photopolymerization initiator, and (D) a photosensitive resin. The cured film obtained from the composition is preferable because the elastic modulus of the cured film is lowered due to the flexibility of the siloxane structure, and the warp of the flexible printed wiring board can be reduced. When the imide ring having excellent properties is contained, the glass transition temperature of the cured film can be increased, and the heat resistance and electrical insulation of the flexible printed wiring board can be improved. The method for laminating the photosensitive coverlay is not particularly limited, but when a photosensitive coverlay ink obtained by dissolving the photosensitive resin composition in an organic solvent is used, the gap filling property between the fine wirings is improved. Is preferable.

<(A) Terminal tetracarboxylic acid siloxane imide oligomer>
The terminal tetracarboxylic acid siloxane imide oligomer of the present invention is an oligomer having a tetracarboxylic acid at the terminal, a siloxane structure inside, and an imide ring closed. Although it will not specifically limit if it is these structures, Preferably, the siloxane diamine shown by following General formula (1),

（式中、Ｒ_１,Ｒ_２はそれぞれ同一でも異なっていてもよく、炭素数１〜１２のアルキル基もしくは芳香族基を示す。ｍは１〜４０の整数、ｎは１〜２０の整数を示す。）
下記一般式（２）で示されるテトラカルボン酸二無水物及び水を、

(Wherein, _{R 1, R 2} may be different from each other in the same, integer .m 1 to 40 represents an alkyl group or an aromatic group having 1 to 12 carbon atoms, n represents an integer of from 1 to 20 Show.)
Tetracarboxylic dianhydride and water represented by the following general formula (2)

（式中、Ｒ_３は４価の有機基を示す。）
モル比でシロキサンジアミンのモル数／テトラカルボン酸二無水物のモル数≦０.８０となるように反応して得られる内部はイミド環を有しており、末端がカルボン酸のシロキサンイミドオリゴマーである。より具体的には、本願発明に好適に用いられるシロキサンジアミンとテトラカルボン酸二無水物のモル比は、１未満、より好ましくは、０.２０以上０.８０以下であり、特に好ましくは０.２５以上０.７０以下である。尚、上記範囲に添加量を制御して反応させることで、末端テトラカルボン酸シロキサンイミドオリゴマーの分子量を最適な範囲に制御することができるので好ましい。０．８０より大きい場合には、オリゴマーの分子量が大きくなり感光性樹脂組成物に用いた場合に、現像することが困難になる場合がある。また、本願発明の末端テトラカルボン酸シロキサンイミドオリゴマーの合成の際には、水を反応させることが必須である。

(In the formula, R ₃ represents a tetravalent organic group.)
The inside obtained by reacting so that the molar ratio of the number of moles of siloxane diamine / the number of moles of tetracarboxylic dianhydride ≦ 0.80 has an imide ring, and the terminal is a siloxane imide oligomer having a carboxylic acid. is there. More specifically, the molar ratio of siloxane diamine and tetracarboxylic dianhydride suitably used in the present invention is less than 1, more preferably 0.20 or more and 0.80 or less, and particularly preferably 0.8. It is 25 or more and 0.70 or less. In addition, since the molecular weight of the terminal tetracarboxylic acid siloxane imide oligomer can be controlled to an optimum range by controlling the addition amount within the above range, it is preferable. If the molecular weight is larger than 0.80, the molecular weight of the oligomer becomes large, and it may be difficult to develop when used in the photosensitive resin composition. In addition, when synthesizing the terminal tetracarboxylic acid siloxane imide oligomer of the present invention, it is essential to react water.

  Preferred are terminal tetracarboxylic acid siloxane imide oligomers having an average molecular weight (weight average molecular weight in terms of polyethylene glycol) of 20,000 or less, particularly an average molecular weight of about 800 to 20,000.

Furthermore, in the present invention, the terminal tetracarboxylic acid siloxane imide oligomer (with an imide ring inside and a terminal carboxyl group) is formed by reacting water during the imidation to open the terminal acid anhydride group. It is preferably used to obtain an acid structure. However, after the imidation reaction, a method may be used in which water is reacted to open a terminal acid anhydride group to obtain a terminal tetracarboxylic acid siloxane imide oligomer.
In addition, when the molar ratio of the tetracarboxylic dianhydride and the siloxane diamine in the present invention is less than 0.50, the tetracarboxylic acid in which the terminal anhydride group of the excess tetracarboxylic dianhydride is ring-opened coexists. However, in the present invention, there is no problem even if such tetracarboxylic acids coexist.

  Examples of the tetracarboxylic dianhydride used as a raw material for the above-mentioned (A) terminal tetracarboxylic acid siloxane imide oligomer include, for example, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, pyromellitic dianhydride 3,3 ′, 4,4′-oxydiphthalic dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 2,2-bis (4-hydroxy Phenyl) propanedibenzoate-3,3 ′, 4,4′-tetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 3,3 ′, 4,4 '-Biphenyltetracarboxylic dianhydride, 2,3,3', 4-biphenyltetracarboxylic dianhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3- It can be used tetracarboxylic acid dianhydride such as cyclohexene-1,2-dicarboxylic anhydride.

  Particularly preferably, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 3,3 In addition to improving the solubility of terminal tetracarboxylic acid siloxane imide oligomers obtained by using ', 4,4'-oxydiphthalic dianhydride in organic solvents, and improving the chemical resistance of polyimide resins Is preferable.

  It is particularly preferable to use 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride from the viewpoint of compatibility with a photosensitive resin or the like.

  The siloxane diamine used in the present invention is preferably a siloxane diamine represented by the following general formula (1),

（式中、Ｒ_１,Ｒ_２はそれぞれ同一でも異なっていてもよく、炭素数１〜１２のアルキル基もしくは芳香族基を示す。ｍは１〜４０の整数、ｎは１〜２０の整数を示す。）
特に本願発明に用いられるシロキサンジアミンの構造は、Ｒ_１,Ｒ_２がメチル基、エチル基、フェニル基であって、ｍは１〜４０、ｎが２以上であるものが好ましく用いられる。

(Wherein, _{R 1, R 2} may be different from each other in the same, integer .m 1 to 40 represents an alkyl group or an aromatic group having 1 to 12 carbon atoms, n represents an integer of from 1 to 20 Show.)
In particular, the structure of the siloxane diamine used in the present invention is preferably such that R ₁ and R ₂ are a methyl group, an ethyl group, and a phenyl group, m is 1 to 40, and n is 2 or more.

Particularly preferably, R ₁ and R ₂ are methyl groups, m is 1 to 20, n is 3 siloxane diamine, or R ₁ and R ₂ are methyl groups or phenyl groups, and n = 3, m A siloxane diamine of 9 to 12 is preferably used. By using this diamine, the imidization temperature can be lowered, the electrical insulation reliability of the polyimide resin can be improved, and good alkaline solution developability can be imparted.

  Various methods are mentioned as a manufacturing method of a terminal tetracarboxylic-acid siloxane imide oligomer. The typical method is illustrated below.

Method 1: A polyamic acid solution is prepared by adding and reacting a siloxane diamine represented by the general formula (1) in a solution in which tetracarboxylic dianhydride is dispersed or dissolved in an organic solvent. After the reaction of tetracarboxylic dianhydride and siloxane diamine is completed, the resulting polyamic acid solution is heated to 100 ° C. or higher and 300 ° C. or lower, more preferably 150 ° C. or higher and 250 ° C. or lower to perform dehydration and imidization. Subsequently, the reaction solution is cooled to 150 ° C. or lower and water is added. More preferably, it is 20 degreeC or more and 150 degrees C or less, Most preferably, they are 40 degreeC or more and 100 degrees C or less. In the imidation, it can be removed from the reaction system while azeotropically boiling with a solvent such as toluene or hexane. The input amount of water is preferably larger than the molar amount of tetracarboxylic dianhydride used.
In addition, it is preferable to use the solvent whose boiling point is 100 degreeC or more as a solvent used by this method. In addition, since the reaction time of each process changes with the raw material to be used, it is preferable to select suitably.

  Method 2: A polyamic acid solution is prepared by adding and reacting a siloxane diamine represented by the general formula (1) in a solution in which tetracarboxylic dianhydride is dispersed or dissolved in an organic solvent. Add an imidization catalyst (preferably tertiary amines such as pyridine, picoline, isoquinoline, trimethylamine, triethylamine, tributylamine, etc.) and a dehydrating agent (acetic anhydride, etc.) to this polyamic acid solution at 60 ° C. or higher. Heat to 180 ° C. or less to imidize. Water is added to the solution that has undergone imidization, or the solution that has undergone imidization is poured into water to cause precipitation. The terminal tetracarboxylic acid siloxane imide oligomer can be obtained by precipitating, filtering and drying the precipitated particles. In addition, when it does not precipitate, it can manufacture by removing a solvent with a vacuum dryer etc.

  Method 3: A polyamic acid solution is prepared by adding and reacting a siloxane diamine represented by the general formula (1) in a solution in which tetracarboxylic dianhydride is dispersed or dissolved in an organic solvent. The polyamic acid solution is placed in a vacuum reduced pressure dryer heated to 100 ° C. or more and 250 ° C. or less, and imidation is performed by drawing a vacuum while heating and drying. A terminal tetracarboxylic acid siloxane imide oligomer can be obtained by reacting this resin with water.

  The above method is preferably used. Regardless of the above method, any method can be used as long as it is a method capable of obtaining a terminal tetracarboxylic acid siloxane imide oligomer having an imide ring inside and a terminal carboxylic acid. There is no problem using it.

  The amount of water to be reacted is 2.0 to 300 times, more preferably 2.0 to 200 times the molar amount of tetracarboxylic dianhydride used, It is preferable to open the ring. It is preferable to include a large amount of water. However, there is no problem outside the above range depending on the reaction method. It is preferable to select an optimal amount as appropriate.

  Examples of the solvent used for the synthesis of the terminal tetracarboxylic acid siloxane imide oligomer include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, and formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide. Acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m- or p -Phenol solvents such as cresol, xylenol, halogenated phenol, catechol, or hexamethylphosphoramide, γ-butyrolactone, methylmonoglyme (1,2-dimethoxyethane), methyldiglyme (bis (2-methoxyether) Ether), methyltriglyme (1,2-bis (2-methoxyethoxy) ethane), methyltetraglyme (bis [2- (2-methoxyethoxyethyl)] ether), ethyl monoglyme (1,2-diethoxy) Ethane), ethyl diglyme (bis (2-ethoxyethyl) ether), symmetric glycol diethers such as butyl diglyme (bis (2-butoxyethyl) ether), γ-butyrolactone and N-methyl-2-pyrrolidone, Methyl acetate, ethyl acetate, isopropyl acetate, n-propyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate (also known as carbitol acetate, 2- (2-butyl acetate) Xyloxy) ethyl)), diethylene glycol monobutyl ether acetate, 3-methoxybutyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol diacetate, 1,3-butylene glycol diacetate Acetates such as dipropylene glycol methyl ether, tripropylene glycol methyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripylene glycol n -Propyl ether, propylene glycol phenyl ether , Dipropylene glycol dimethyl ether, 1,3-dioxolane, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, a solvent may be used ethers such as ethyl ether also ethylene glycol. If necessary, low-boiling hexane, acetone, toluene, xylene and the like can be used in combination.

  Among them, symmetric glycol diethers are particularly preferable because of high solubility of oligomers.

<(B) Diamino Compound>
In the present invention, the (B) diamino compound is a compound having two or more amino groups. Preferably, it is an aromatic diamine represented by the following general formula (3).

（式中、Ｒ_４は、２価の有機基である。）
上記ジアミノ化合物の中で、より具体的には、ｍ−フェニレンジアミン、ｏ−フェニレンジアミン、ｐ−フェニレンジアミン、ｍ−アミノベンジルアミン、ｐ−アミノベンジルアミン、ビス（３−アミノフェニル）スルフィド、（３−アミノフェニル）（４−アミノフェニル）スルフィド、ビス（４−アミノフェニル）スルフィド、ビス（３−アミノフェニル）スルホキシド、（３−アミノフェニル）（４−アミノフェニル）スルホキシド、ビス（４−アミノフェニル）スルホキシド、ビス（３−アミノフェニル）スルホン、（３−アミノフェニル）（４−アミノフェニル）スルホン、ビス（４−アミノフェニル）スルホン、３，４’−ジアミノベンゾフェノン、４，４’−ジアミノベンゾフェノン、３，３’−ジアミノベンゾフェノン、３，３’−ジアミノジフェニルメタン、３，４’−ジアミノジフェニルメタン、４，４’−ジアミノジフェニルメタン、４，４’−ジアミノジフェニルエーテル、３，３’−ジアミノジフェニルエーテル、３，４’−ジアミノジフェニルエーテル、ビス［４−（３−アミノフェノキシ）フェニル］スルホキシド、ビス［４−（アミノフェノキシ）フェニル］スルホキシド、（４−アミノフェノキシフェニル）（３−アミノフェノキシフェニル）フェニル］スルホキシド、ビス［４−（３−アミノフェノキシ）フェニル］スルホン、ビス［４−（４−アミノフェノキシ）フェニル］スルホン、（４−アミノフェノキシフェニル）（３−アミノフェノキシフェニル）フェニル］スルホン、ビス［４−（３−アミノフェノキシ）フェニル］スルフィド、ビス［４−（アミノフェノキシ）フェニル］スルフィド、（４−アミノフェノキシフェニル）（３−アミノフェノキシフェニル）フェニル］スルフィド、３，３’−ジアミノベンズアニリド、３，４’−ジアミノベンズアニリド、４，４’−ジアミノベンズアニリド、ビス［４−（３−アミノフェノキシ）フェニル］メタン、ビス［４−（４−アミノフェノキシ）フェニル］メタン、[４−（４−アミノフェノキシフェニル）][４−（３−アミノフェノキシフェニル）]メタン、１，１−ビス［４−（３−アミノフェノキシ）フェニル］エタン、１，１−ビス［４−（４−アミノフェノキシ）フェニル］エタン、１，１−[４−（４−アミノフェノキシフェニル）][４−（３−アミノフェノキシフェニル）]エタン、１，２−ビス［４−（３−アミノフェノキシ）フェニル］エタン、１，２−ビス［４−（４−アミノフェノキシ）フェニル］エタン、１，２−[４−（４−アミノフェノキシフェニル）][４−（３−アミノフェノキシフェニル）]エタン、２，２−ビス［４−（３−アミノフェノキシ）フェニル］プロパン、２，２−ビス［４−（４−アミノフェノキシ）フェニル］プロパン、２，２−[４−（４−アミノフェノキシフェニル）][４−（３−アミノフェノキシフェニル）] プロパン、２，２−ビス［３−（３−アミノフェノキシ）フェニル］−１，１，１，３，３，３−ヘキサフルオロプロパン、２，２−ビス［４−（４−アミノフェノキシ）フェニル］−１，１，１，３，３，３−ヘキサフルオロプロパン、２，２−[４−（４−アミノフェノキシフェニル）][４−（３−アミノフェノキシフェニル）] −１，１，１，３，３，３−ヘキサフルオロプロパン、１，３−ビス（３−アミノフェノキシ）ベンゼン、１，４−ビス（３−アミノフェノキシ）ベンゼン、１，４−ビス（４−アミノフェノキシ）ベンゼン、１，３−ビス（４−アミノフェノキシ）ベンゼン、４，４’−ビス（４−アミノフェノキシ）ビフェニル、４，４’−ビス（３−アミノフェノキシ）ビフェニル、ビス［４−（３−アミノフェノキシ）フェニル］ケトン、ビス［４−（４−アミノフェノキシ）フェニル］ケトン、ビス［４−（３−アミノフェノキシ）フェニル］エーテル、ビス［４−（４−アミノフェノキシ）フェニル］エーテル、ポリテトラメチレンオキシド−ジ−Ｐ−アミノベンゾエート、ポリ（テトラメチレン／３−メチルテトラメチレンエーテル）グリコールビス（４−アミノベンゾエート）、トリメチレン―ビス（４−アミノベンゾエート）、ｐ-フェニレン−ビス（４−アミノベンゾエート）、ｍ−フェニレン−ビス（４−アミノベンゾエート）、ビスフェノールＡ−ビス（４−アミノベンゾエート）、２，４−ジアミノ安息香酸、２，５−ジアミノ安息香酸、３，５−ジアミノ安息香酸、３，３’−ジアミノ−４，４’−ジカルボキシビフェニル、４，４’−ジアミノ−３，３’−ジカルボキシビフェニル、４，４’−ジアミノ−２，２’−ジカルボキシビフェニル、[ビス(４-アミノ-２-カルボキシ)フェニル]メタン、 [ビス(４-アミノ-３-カルボキシ)フェニル]メタン、[ビス(３-アミノ-４-カルボキシ)フェニル]メタン、 [ビス(３-アミノ-５-カルボキシ)フェニル]メタン、２，２−ビス[３−アミノ−４−カルボキシフェニル]プロパン、２，２−ビス[４−アミノ−３−カルボキシフェニル]プロパン、２，２−ビス[３−アミノ−４−カルボキシフェニル]ヘキサフルオロプロパン、２，２−ビス[４−アミノ−３−カルボキシフェニル]ヘキサフルオロプロパン、３，３’−ジアミノ−４，４’−ジカルボキシジフェニルエーテル、４，４‘−ジアミノ−３，３’−ジカルボキシジフェニルエーテル、４，４’−ジアミノ−２，２’−ジカルボキシジフェニルエーテル、３，３’−ジアミノ−４，４‘−ジカルボキシジフェニルスルフォン、４，４’−ジアミノ−３，３’−ジカルボキシジフェニルスルフォン、４，４’−ジアミノ−２，２’−ジカルボキシジフェニルスルフォン、２，３−ジアミノフェノール、２，４−ジアミノフェノール、２，５−ジアミノフェノール、３，５−ジアミノフェノール等のジアミノフェノール類、３，３’−ジアミノ−４，４’−ジヒドロキシビフェニル、４，４’−ジアミノ−３，３’−ジヒドロキシビフェニル、４，４’−ジアミノ−２，２’−ジヒドロキシビフェニル、４，４’−ジアミノ−２，２’，５，５’−テトラヒドロキシビフェニル等のヒドロキシビフェニル化合物類、３，３’−ジアミノ−４，４’−ジヒドロキシジフェニルメタン、４，４’−ジアミノ−３，３’−ジヒドロキシジフェニルメタン、４，４’−ジアミノ−２，２’−ジヒドロキシジフェニルメタン等のジヒドロキシジフェニルメタン類、２，２−ビス[３−アミノ−４−ヒドロキシフェニル]プロパン、２，２−ビス[４−アミノ−３−ヒドロキシフェニル]プロパン等のビス[ヒドロキシフェニル]プロパン類、２，２−ビス[３−アミノ−４−ヒドロキシフェニル]ヘキサフルオロプロパン、２，２−ビス[３−アミノ−４−ヒドロキシフェニル]ヘキサフルオロプロパン等のビス[ヒヒドロキシフェニル]ヘキサフルオロプロパン類、３，３’−ジアミノ−４，４’−ジヒドロキシジフェニルエーテル、４，４’−ジアミノ−３，３’−ジヒドロキシジフェニルエーテル、４，４’−ジアミノ−２，２’−ジヒドロキシジフェニルエーテル等のヒドロキシジフェニルエーテル類、３，３’−ジアミノ−４，４’−ジヒドロキシジフェニルスルフォン、４，４’−ジアミノ−３，３’−ジヒドロキシジフェニルスルフォン、４，４’−ジアミノ−２，２’−ジヒドロキシジフェニルスルフォン等のジヒドロキシジフェニルスルフォン類、３，３’−ジアミノ−４，４’−ジヒドロキシジフェニルスルフィド、４，４’−ジアミノ−３，３’−ジヒドロキシジフェニルスルフィド、４，４’−ジアミノ−２，２’−ジヒドロキシジフェニルスルフィド等のジヒドロキシジフェニルスルフィド類、３，３’−ジアミノ−４，４’−ジヒドロキシジフェニルスルホキシド、４，４’−ジアミノ−３，３’−ジヒドロキシジフェニルスルホキシド、４，４’−ジアミノ−２，２’−ジヒドロキシジフェニルスルホキシド等のジヒドロキシジフェニルスルホキシド類、２，２−ビス[４−（４−アミノ−３−ヒドロキシフェノキシ）フェニル]プロパン等のビス［（ヒドロキシフェニル）フェニル］アルカン化合物類、４，４’−ビス（４−アミノ−３−ヒドキシフェノキシ）ビフェニル等のビス（ヒドキシフェノキシ）ビフェニル化合物類、２，２−ビス[４−（４−アミノ−３−ヒドロキシフェノキシ）フェニル]スルフォン等のビス[（ヒドロキシフェノキシ）フェニル]スルフォン化合物、４，４’−ジアミノ−３，３’−ジハイドロキシジフェニルメタン、４，４’−ジアミノ−２，２’−ジハイドロキシジフェニルメタン、２，２−ビス[３−アミノ−４−カルボキシフェニル]プロパン、４，４’−ビス（４−アミノ−３−ヒドキシフェノキシ）ビフェニル等のビス（ヒドキシフェノキシ）ビフェニル化合物類をあげることができる。

(In the formula, R ₄ is a divalent organic group.)
Among the diamino compounds, more specifically, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, bis (3-aminophenyl) sulfide, ( 3-aminophenyl) (4-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfoxide, (3-aminophenyl) (4-aminophenyl) sulfoxide, bis (4-amino) Phenyl) sulfoxide, bis (3-aminophenyl) sulfone, (3-aminophenyl) (4-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, 3,4'-diaminobenzophenone, 4,4'-diamino Benzophenone, 3,3′-diaminobenzophenone, 3,3 ′ -Diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, bis [4- (3 -Aminophenoxy) phenyl] sulfoxide, bis [4- (aminophenoxy) phenyl] sulfoxide, (4-aminophenoxyphenyl) (3-aminophenoxyphenyl) phenyl] sulfoxide, bis [4- (3-aminophenoxy) phenyl] Sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, (4-aminophenoxyphenyl) (3-aminophenoxyphenyl) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [ 4- Aminophenoxy) phenyl] sulfide, (4-aminophenoxyphenyl) (3-aminophenoxyphenyl) phenyl] sulfide, 3,3′-diaminobenzanilide, 3,4′-diaminobenzanilide, 4,4′-diaminobenz Anilide, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, [4- (4-aminophenoxyphenyl)] [4- (3-aminophenoxyphenyl) )] Methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,1- [4- (4- Aminophenoxyphenyl)] [4- (3-aminophenoxyphenyl)] ethane, 1,2-bis [4- (3-aminophenoxy) fur Nyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2- [4- (4-aminophenoxyphenyl)] [4- (3-aminophenoxyphenyl)] ethane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2- [4- (4-aminophenoxyphenyl) ] [4- (3-aminophenoxyphenyl)] propane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2 -Bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2- [4- (4-aminophenoxyphenyl)] [4- (3 -Aminophenoxypheny )]-1,1,1,3,3,3-hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) ) Phenyl] ether, polytetramethylene oxide-di-P-aminobenzoate, poly (tetramethylene / 3-methyltetramethylene ether) glyco Rubis (4-aminobenzoate), trimethylene-bis (4-aminobenzoate), p-phenylene-bis (4-aminobenzoate), m-phenylene-bis (4-aminobenzoate), bisphenol A-bis (4-amino) Benzoate), 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 3,3′-diamino-4,4′-dicarboxybiphenyl, 4,4′-diamino- 3,3′-dicarboxybiphenyl, 4,4′-diamino-2,2′-dicarboxybiphenyl, [bis (4-amino-2-carboxy) phenyl] methane, [bis (4-amino-3-carboxy ) Phenyl] methane, [bis (3-amino-4-carboxy) phenyl] methane, [bis (3-amino-5-carboxy) phenyl] methane, 2,2-bis [3-amino-4- Ruboxyphenyl] propane, 2,2-bis [4-amino-3-carboxyphenyl] propane, 2,2-bis [3-amino-4-carboxyphenyl] hexafluoropropane, 2,2-bis [4- Amino-3-carboxyphenyl] hexafluoropropane, 3,3′-diamino-4,4′-dicarboxydiphenyl ether, 4,4′-diamino-3,3′-dicarboxydiphenyl ether, 4,4′-diamino- 2,2′-dicarboxydiphenyl ether, 3,3′-diamino-4,4′-dicarboxydiphenyl sulfone, 4,4′-diamino-3,3′-dicarboxydiphenyl sulfone, 4,4′-diamino- 2,2′-dicarboxydiphenylsulfone, 2,3-diaminophenol, 2,4-diaminophenol, 2,5-diaminophenol , Diaminophenols such as 3,5-diaminophenol, 3,3′-diamino-4,4′-dihydroxybiphenyl, 4,4′-diamino-3,3′-dihydroxybiphenyl, 4,4′- Hydroxybiphenyl compounds such as diamino-2,2′-dihydroxybiphenyl, 4,4′-diamino-2,2 ′, 5,5′-tetrahydroxybiphenyl, 3,3′-diamino-4,4′-dihydroxy Dihydroxydiphenylmethanes such as diphenylmethane, 4,4′-diamino-3,3′-dihydroxydiphenylmethane, 4,4′-diamino-2,2′-dihydroxydiphenylmethane, 2,2-bis [3-amino-4-hydroxy Bis [hydroxyphenyl] propanes such as phenyl] propane and 2,2-bis [4-amino-3-hydroxyphenyl] propane Bis [hyhydroxyphenyl] hexafluoropropanes such as 2,2-bis [3-amino-4-hydroxyphenyl] hexafluoropropane, 2,2-bis [3-amino-4-hydroxyphenyl] hexafluoropropane, Hydroxydiphenyl ethers such as 3,3′-diamino-4,4′-dihydroxydiphenyl ether, 4,4′-diamino-3,3′-dihydroxydiphenyl ether, 4,4′-diamino-2,2′-dihydroxydiphenyl ether, Dihydroxy such as 3,3′-diamino-4,4′-dihydroxydiphenyl sulfone, 4,4′-diamino-3,3′-dihydroxydiphenyl sulfone, 4,4′-diamino-2,2′-dihydroxydiphenyl sulfone Diphenyl sulfones, 3,3′-diamino-4,4′-dihydro Dihydroxydiphenyl sulfides such as sidiphenyl sulfide, 4,4′-diamino-3,3′-dihydroxydiphenyl sulfide, 4,4′-diamino-2,2′-dihydroxydiphenyl sulfide, 3,3′-diamino-4 , 4'-dihydroxydiphenyl sulfoxide, 4,4'-diamino-3,3'-dihydroxydiphenyl sulfoxide, dihydroxydiphenyl sulfoxides such as 4,4'-diamino-2,2'-dihydroxydiphenyl sulfoxide, 2,2- Bis [(hydroxyphenyl) phenyl] alkane compounds such as bis [4- (4-amino-3-hydroxyphenoxy) phenyl] propane, 4,4′-bis (4-amino-3-hydroxyphenoxy) biphenyl, etc. Bis (hydroxyphenoxy) biphenyl compounds, 2,2 Bis [(hydroxyphenoxy) phenyl] sulfone compounds such as bis [4- (4-amino-3-hydroxyphenoxy) phenyl] sulfone, 4,4′-diamino-3,3′-dihydroxydiphenylmethane, 4,4 ′ -Bis such as diamino-2,2'-dihydroxydiphenylmethane, 2,2-bis [3-amino-4-carboxyphenyl] propane, 4,4'-bis (4-amino-3-hydroxyphenoxy) biphenyl (Hydroxyphenoxy) biphenyl compounds can be mentioned.

  In particular, diamines that can be suitably used for a photosensitive resin composition laminated as a photosensitive coverlay on the flexible printed wiring board of the present invention include m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, and bis ( 3-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3, 4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, bis [4- (3-aminophenoxy) phenyl] Sulfone, bis [4- (4 Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 2,2-bis [4- (3-aminophenoxy) phenyl ] Propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2- [4- (4-aminophenoxyphenyl)] [4- (3-aminophenoxyphenyl)] propane, 2 , 2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1 , 1,1,3,3,3-hexafluoropropane, 2,2- [4- (4-aminophenoxyphenyl)] [4- (3-aminophenoxyphenyl)]-1,1,1,3 , 3-hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3- Bis (4-aminophenoxy) benzene, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, polytetramethylene oxide-di-P-aminobenzoate, poly (Tetramethylene / 3-methyltetramethylene ether) glycol bis (4-aminobenzoate), trimethylene-bis (4-aminobenzoate), p-phenylene-bis (4-aminobenzoate), m-phenylene-bis (4- Aminobenzoate), bisphenol A-bis (4-aminobenzoate) It is preferably used. It is preferable to use the aromatic diamine because the heat resistance of the photosensitive resin composition is improved.

The compounding amount of the diamino compound in the present invention is such that (A) component and (B) component in the photosensitive resin composition are:
(A) the molar amount of the acid dianhydride of component (A),
(B) the molar amount of the siloxane diamine of component (A),
(C) It is preferable that (a) / ((b) + (c)) is blended so as to be 0.80 or more and 1.20 or less when the molar amount of the component (B) diamine is used. .

  By making it within the above range, the chain extension reaction of the terminal tetracarboxylic acid siloxane imide oligomer easily proceeds by the diamine compound, and it becomes easy to produce a high molecular weight polyimide resin in the photosensitive resin composition, and the photosensitive resin composition. This is preferable because the heat resistance, chemical resistance and flex resistance after curing of the resin are improved.

<(C) Photopolymerization initiator>
The photopolymerization initiator (C) in the present invention is activated by absorbing light when irradiated with light, causing a reaction such as a cleavage reaction, a hydrogen abstraction reaction, or an electron transfer. It is a compound that generates a substance that initiates a photopolymerization reaction, such as ions.

  For example, Michler's ketone, 4,4′-bis (diethylamino) benzophenone, 4,4 ′, 4 ″ -tris (dimethylamino) triphenylmethane, 2,2′-bis (2-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-diimidazole, acetophenone, benzoin, 2-methylbenzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether 2-t-butylanthraquinone, 1,2-benzo-9,10-anthraquinone, methylanthraquinone, thioxanthone, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, diacetylbenzyl, benzyldimethylketa -Ru, benzyldie Tilketal, 2 (2′-furylethylidene) -4,6-bis (trichloromethyl) -S-triazine, 2 [2 ′ (5 ″ -methylfuryl) ethylidene] -4,6-bis (trichloromethyl) ) -S-triazine, 2 (p-methoxyphenyl) -4,6-bis (trichloromethyl) -S-triazine, 2,6-di (p-azidobenzal) -4-methylcyclohexanone, 4,4'-di Azidochalcone, di (tetraalkylammonium) -4,4′-diazidostilbene-2,2′-disulfonate, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl -Phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2- Hydroxy-2-methyl-1-propan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane-1, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine Oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2-hydroxy-2-methyl-1-phenyl-propane-1-ketone, bis (n5-2,4-cyclopentadien-1-yl) -Bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium, 1,2-octanonedio , 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], iododium, (4-methylphenyl) [4- (2-methylpropyl) phenyl] -hexafluorophosphate (1- ), Ethyl-4-dimethylaminobenzoate, 2-ethylhexyl-4-dimethylaminobenzoate, ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- These may be used alone or in combination of two or more, such as (O-acetyloxyome).

  The amount of the photopolymerization initiator used in the present invention is such that the component (C) is 0.1 to 50 parts by weight with respect to 100 parts by weight of the solid content of the components (A) and (B). It is preferable to do. Particularly preferred is 0.1 to 10 parts by weight. When the amount is less than the above range, the curing reaction of the acrylic resin at the time of light irradiation may hardly occur and may not occur easily, and the curing may be insufficient. In addition, when the amount is large, it may be difficult to adjust the light irradiation amount, and an overexposure state may occur and good resolution may not be obtained. Therefore, in order to advance the photocuring reaction efficiently, it is preferable to adjust within the above range.

<(D) Photosensitive resin>
The photosensitive resin (D) in the present invention is a resin in which a chemical bond is formed by a photopolymerization initiator. Among these, a resin having at least one unsaturated double bond in the molecule is preferable. Furthermore, the unsaturated double bond is an acryl group (CH2 = CH-group), a methacryloyl group (CH = C (CH3) -group) or a vinyl group (-CH = CH-group). preferable.

  For example, bisphenol F EO modified (n = 2-50) diacrylate, bisphenol A EO modified (n = 2-50) diacrylate, bisphenol S EO modified (n = 2-50) diacrylate, bisphenol F EO modified (n = 2-50) dimethacrylate, bisphenol A EO modified (n = 2-50) dimethacrylate, bisphenol S EO modified (n = 2-50) dimethacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, Ethylene glycol diacrylate, pentaerythritol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, tetramethylolpropane tetraacrylate Tetraethylene glycol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, ethylene glycol dimethacrylate, pentaerythritol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, dipentaerythritol hexamethacrylate, tetramethylol Propane tetramethacrylate, tetraethylene glycol dimethacrylate, methoxydiethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, β-methacryloyloxyethyl hydrogen phthalate, β-methacryloyloxyethyl hydrogen succinate, 3-chloro-2-hydroxypropyl methacrylate, Allyl methacrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxy polyethylene glycol acrylate, β-acryloyloxyethyl hydrogen succinate, lauryl acrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1 , 3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2-hydroxy-1,3-dimethacryloxypropane, 2,2-bis [4- ( Methacryloxyethoxy) phenyl] propane, 2,2-bi [4- (methacryloxy / diethoxy) phenyl] propane, 2,2-bis [4- (methacryloxy / polyethoxy) phenyl] propane, polyethylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 2,2- Bis [4- (acryloxy-diethoxy) phenyl] propane, 2,2-bis [4- (acryloxy-polyethoxy) phenyl] propane, 2-hydroxy-1-acryloxy-3-methacryloxypropane, trimethylolpropane trimethacrylate, Tetramethylol methane triacrylate, tetramethylol methane tetraacrylate, methoxydipropylene glycol methacrylate, methoxytriethylene glycol acrylate, nonylphenol Xylethylene glycol acrylate, nonylphenoxy polypropylene glycol acrylate, 1-acryloyloxypropyl-2-phthalate, isostearyl acrylate, polyoxyethylene alkyl ether acrylate, nonylphenoxyethylene glycol acrylate, polypropylene glycol dimethacrylate, 1,4-butanediol di Methacrylate, 3-methyl-1,5-pentanediol dimethacrylate, 1,6-mexanediol dimethacrylate, 1,9-nonanediol methacrylate, 2,4-diethyl-1,5-pentanediol dimethacrylate, 1, 4-cyclohexanedimethanol dimethacrylate, dipropylene glycol diacrylate, tricyclodecane dimethanol dia Chryrate, 2,2-hydrogenated bis [4- (acryloxy polyethoxy) phenyl] propane, 2,2-bis [4- (acryloxy polypropoxy) phenyl] propane, 2,4-diethyl-1,5-pentane Diol diacrylate, ethoxylated totimethylolpropane triacrylate, propoxylated tomethylolpropane triacrylate, isocyanuric acid tri (ethane acrylate), pentathritol tetraacrylate, ethoxylated pentathritol tetraacrylate, propoxylated pentathritol tetraacrylate, Ditrimethylolpropane tetraacrylate, dipentaerythritol polyacrylate, triallyl isocyanurate, glycidyl methacrylate, glycidyl allyl ether, 1,3,5-triac Liloylhexahydro-s-triazine, triallyl 1,3,5-benzenecarboxylate, triallylamine, triallyl citrate, triallyl phosphate, allobarbital, diallylamine, diallyldimethylsilane, diallyl disulfide, diallyl ether, zalyl sialate Diallyl isophthalate, diallyl terephthalate, 1,3-dialyloxy-2-propanol, diallyl sulfide diallyl maleate, 4,4′-isopropylidene diphenol dimethacrylate, 4,4′-isopropylidene diphenol diacrylate, etc. Although preferable, it is not limited to these. In particular, the repeating unit of EO (ethylene oxide) contained in one molecule of diacrylate or methacrylate is preferably in the range of 2-50, more preferably 2-40. By using a product having an EO repeating unit in the range of 2 to 50, the solubility in an aqueous developer typified by an alkaline aqueous solution is improved, and the development time is shortened. Furthermore, there is a feature that stress hardly remains in the cured film obtained by curing the photosensitive resin composition, and the printed wiring board can be prevented from warping when laminated on the flexible printed wiring board of the present invention.

  In particular, it is particularly preferable to use the EO-modified diacrylate or dimethacrylate together with an acrylic resin having 3 or more acryl groups or methacryl groups in order to improve developability. Ethoxylated isocyanuric acid EO modified trimethacrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol Triacrylate, ethoxylated pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, ditrimethylol B bread tetraacrylate, ditrimethylolpropane tetraacrylate, propoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, acrylic resins such as dipentaerythritol hexaacrylate is preferably used.

In addition, hydroxyl groups in the molecular structure skeleton such as 2-hydroxy-3-phenoxypropyl acrylate, monohydroxyethyl acrylate phthalate, ω-carboxy-polycaprolactone monoacrylate, acrylic acid dimer, pentaerythritol tri and tetraacrylate, Those having a carbonyl group are also preferably used.
In addition, any photosensitive resin such as an epoxy-modified acrylic (methacrylic) resin, a urethane-modified acrylic (methacrylic) resin, or a polyester-modified acrylic (methacrylic) resin may be used.

<The mixing method of (A)-(D)>
The photosensitive resin composition is obtained by uniformly mixing the components (A) to (D). As a method of uniformly mixing, for example, a general kneading apparatus such as a three roll or bead mill apparatus may be used for mixing. Moreover, when the viscosity of a solution is low, you may mix using a general stirring apparatus.

<Other ingredients>
The photosensitive resin composition further includes a thermosetting resin such as an epoxy resin, a filler, an adhesion aid, a leveling agent, a polymerization inhibitor, an antioxidant, a silane coupling agent, and an antifoaming agent, as necessary. Various additives such as can be added. As the filler, a fine inorganic filler such as silica, mica, talc, barium sulfate, wollastonite, calcium carbonate, or a fine organic polymer filler may be contained. It is preferable to select the content appropriately.

<Photosensitive resin composition solution>
The photosensitive resin composition is highly soluble in various organic solvents, such as sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, and formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide. Acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m- or p -Phenol solvents such as cresol, xylenol, halogenated phenol, catechol, or hexamethylphosphoramide, γ-butyrolactone, methylmonoglyme (1,2-dimethoxyethane), methyldiglyme (bis (2-methoxyether) Ether), methyltriglyme 1,2-bis (2-methoxyethoxy) ethane), methyltetraglyme (bis [2- (2-methoxyethoxyethyl)] ether), ethyl monoglyme (1,2-diethoxyethane), ethyldiglyme ( Symmetric glycol diethers such as bis (2-ethoxyethyl) ether) and butyldiglyme (bis (2-butoxyethyl) ether), γ-butyrolactone, N-methyl-2-pyrrolidone, methyl acetate, ethyl acetate, isopropyl Acetate, n-propyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate (also known as carbitol acetate, 2- (2-butoxyethoxy) ethyl acetate)), di Acetates such as tylene glycol monobutyl ether acetate, 3-methoxybutyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol diacetate, 1,3-butylene glycol diacetate, , Dipropylene glycol methyl ether, tripropylene glycol methyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripylene glycol n-propyl ether, propylene Glycol phenyl ether, dipropylene glycol dimethyl Ether, 1,3-dioxolane, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, a solvent may be used ethers such as ethyl ether also ethylene glycol. If necessary, low-boiling hexane, acetone, toluene, xylene and the like can be used in combination.

  Among these, symmetric glycol diethers are particularly preferable because the solubility of the photosensitive resin composition is high.

  In the photosensitive resin composition solution, the organic solvent is 10 parts by weight or more and 100 parts by weight with respect to 100 parts by weight of the total solid content of the components (A), (B), (C), and (D). It is preferable that it is blended in less than or equal to parts.

  A photosensitive resin composition solution within this range is preferable because the film reduction rate after coating and drying is reduced.

<Usage method of photosensitive resin composition>
The photosensitive resin composition can be laminated directly on the flexible printed wiring board as follows, or after preparing the photosensitive resin composition solution. First, the photosensitive resin composition is applied to a substrate and dried to remove the organic solvent. The substrate can be applied by screen printing, curtain roll, river roll, spray coating, spin coating using a spinner, or the like. Drying of the coating film (preferably thickness: 5 to 100 μm, particularly 10 to 100 μm) is performed at 120 ° C. or less, preferably 40 to 100 ° C. After drying, a negative photomask is placed on the dried coating film and irradiated with actinic rays such as ultraviolet rays, visible rays, and electron beams. Next, the relief pattern can be obtained by washing out the unexposed portion with a developer using various methods such as shower, paddle, immersion, or ultrasonic wave. Since the time until the pattern is exposed varies depending on the spraying pressure and flow velocity of the developing device and the temperature of the etching solution, it is preferable to find optimal apparatus conditions as appropriate.

  As the developer, an alkaline aqueous solution is preferably used. This developer may contain a water-soluble organic solvent such as methanol, ethanol, n-propanol, isopropanol, or N-methyl-2-pyrrolidone. Examples of the alkaline compound that gives the alkaline aqueous solution include hydroxides, carbonates, hydrogen carbonates, amine compounds, and the like of alkali metals, alkaline earth metals, or ammonium ions, specifically sodium hydroxide. , Potassium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetraisopropylammonium Hydroxide, N-methyldiethanolamine, N-ethyldiethanolamine, N, N-dimethylethanolamine, triethanolamine, triisopropanolamine, trii Such as propylamine can be mentioned, the aqueous solution is a compound other than this as long as it exhibits basicity can also be naturally used. The concentration of the alkaline compound that can be suitably used in the development step of the photosensitive resin composition of the present invention is preferably 0.01 to 20% by weight, particularly preferably 0.02 to 10% by weight. Further, the temperature of the developer depends on the composition of the photosensitive resin composition and the composition of the alkali developer, and is generally 0 ° C. or higher and 80 ° C. or lower, more generally 10 ° C. or higher and 60 ° C. or lower. Is preferably used.

  The relief pattern formed by the developing process is rinsed to remove unnecessary residues. Examples of the rinsing liquid include water and acidic aqueous solutions.

Next, a cured film rich in heat resistance can be obtained by subjecting the terminal carboxylic acid siloxane imide oligomer to chain extension with a diamino compound by performing heat curing treatment. Although a cured film is determined in consideration of wiring thickness etc., it is preferable that thickness is about 2-50 micrometers. It is desired that the final curing temperature at this time can be imidized by heating at a low temperature for the purpose of preventing oxidation of the wiring and the like and not reducing the adhesion between the wiring and the substrate.
The heat curing temperature applied at this time is preferably 100 ° C. or higher and 250 ° C. or lower, more preferably 120 ° C. or higher and 200 ° C. or lower, and particularly preferably 130 ° C. or higher and 190 ° C. or lower. If the final heating temperature is high, the wiring is oxidatively deteriorated, which is not desirable.

  When the warp of the flexible printed wiring board in which the wiring pattern is protected by the photosensitive cover lay obtained by laminating and curing the photosensitive resin composition on the flexible printed wiring board exceeds 2 mm, the flexibility is poor. Therefore, when used for component mounting, the handling becomes poor, and the defect occurrence rate may increase.

  The flexible printed wiring board in which the wiring pattern is protected by the photosensitive cover lay thus obtained can be finely processed, has a small warp, is highly flexible, and has a high electrical insulation property with a thin film. Are better.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

(Synthesis Example 1)
200 g (0.384 mol) of 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride (hereinafter abbreviated as BPADA) was converted into 154 g of 1,2-bis (2-methoxyethoxy) ethane. Dispersed and kept at 80 ° C. To this, 159 g (0 from Shin-Etsu Chemical Co., Ltd .: product name KF8010, molecular weight 830, R ₃ and R ₄ in the general formula (2) are methyl groups, n = 3, m = 6 to 11). 192 mol) and stirred uniformly for 30 minutes. Next, the mixture was heated to 140 ° C. and stirred uniformly for 1 hour, heated to 180 ° C. and heated to reflux for 3 hours to carry out an imidization reaction. After cooling to 80 ° C., 27.7 g (1.54 mol) of water was added, and the mixture was heated to reflux for 5 hours. In this way, a terminal tetracarboxylic acid resin containing a terminal tetracarboxylic acid siloxane imide oligomer was obtained. The solid content concentration of this solution was 66% by weight, and the viscosity of the solution was 100 poise at 23 ° C. This terminal tetracarboxylic acid resin solution was a stable solution with little change in viscosity even when it was allowed to stand at room temperature for 1 month. This synthetic resin is abbreviated as resin A.

(Synthesis Example 2)
The water charged after the reaction in Synthesis Example 1 was changed to methanol and half-esterified. This synthetic resin is abbreviated as resin B.

(Examples 1-4)
A diamino compound, a photopolymerization initiator, a photosensitive resin, an epoxy resin, a filler, and an organic solvent were added to the terminal tetracarboxylic acid resin obtained in Synthesis Example 1 to prepare a photosensitive resin composition. Table 1 shows the blending amount of each constituent raw material in the resin solid content and the kind of the raw material. In addition, 1,2-bis (2-methoxyethoxy) ethane which is a solvent in the table is the total amount of solvent including the solvent and the like contained in the above synthetic resin solution and the like.

  The photosensitive resin composition was first mixed with a general stirring device equipped with a stirring blade, and the solution was passed twice with a three-roll mill to obtain a uniform solution. When the particle diameter was measured with a grindometer, all were 10 μm or less. The following evaluation was carried out by completely defoaming the foam in the solution with a defoaming device. The evaluation results are shown in Table 2.

※１ 日本化薬株式会社製 製品名ＺＡＲ−１３９５Ｈ 酸変性エポキシアクリレート樹脂
※２ チバスペシャルティケミカルズ社製 製品名ＩＲＧＡＣＵＲＥ ８１９ ビス（２，４，６−トリメチルベンゾイル）−フェニルフォスフィンオキサイド
※３ 新中村化学社製 製品名ＮＫエステルＢＰＥ−５００ ＥＯ変性ビスフェノールＡジアクリレート 分子量が５００
※４ 大日本インキ株式会社製 クレゾールノボラック型の多官能エポキシ樹脂
※５ 日本アエロジル株式会社製 シリカ粒子。

* 1 Product name ZAR-1395H manufactured by Nippon Kayaku Co., Ltd. Acid-modified epoxy acrylate resin
* 2 Product name IRGACURE 819 Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide manufactured by Ciba Specialty Chemicals * 3 Product name NK ester BPE-500 EO-modified bisphenol A diacrylate with a molecular weight of 500
* 4 A cresol novolac type polyfunctional epoxy resin manufactured by Dainippon Ink Co., Ltd. * 5 Silica particles manufactured by Nippon Aerosil Co., Ltd.

(Preparation of coating on flexible printed wiring board)
A comb-shaped pattern of line width / space width = 100 μm / 100 μm on a flexible copper-laminated laminate (copper foil thickness 12 μm, polyimide film is Apical 25 NPI manufactured by Kaneka Corporation, and copper foil is bonded with a polyimide adhesive) A flexible printed wiring board was prepared for evaluation. This flexible printed wiring board was immersed in a 10% by volume sulfuric acid aqueous solution for 1 minute, and then washed with pure water to treat the surface of the copper foil.

  The photosensitive resin composition was applied onto the prepared flexible printed wiring board using a Baker type applicator so that the final dry thickness was 25 μm, dried at 80 ° C. for 20 minutes, and then irradiated with 300 mJ / cm 2 of ultraviolet light. And exposed. After completion of exposure, spray development was performed at a discharge pressure of 1.0 kgf / mm 2 using a solution obtained by heating a 1.0 wt% aqueous sodium carbonate solution to 30 ° C. After the development, it was washed purely and sufficiently, and then heated and dried in an oven at 170 ° C. for 60 minutes to produce a flexible printed wiring board protected by a photosensitive coverlay layer.

(Photosensitivity evaluation)
Evaluation of the photosensitivity of the photosensitive resin composition is carried out by using the above-mentioned photosensitive resin composition on a 75 μm polyimide film (manufactured by Kaneka Co., Ltd .: trade name 75NPI) using a Baker type applicator so that the final dry thickness becomes 25 μm. The film was cast and applied to an area of 100 mm × 100 mm, dried at 80 ° C. for 20 minutes, and then a negative photomask of 50 mm × 50 mm area / line width = 100 μm / 100 μm was placed and 300 mJ / cm 2 of ultraviolet light And exposed. After completion of exposure, spray development was performed at a discharge pressure of 1.0 kgf / mm 2 using a solution obtained by heating a 1.0 wt% aqueous sodium carbonate solution to 30 ° C. After the development, it was washed purely and sufficiently, and then dried by heating in an oven at 170 ° C. for 60 minutes to prepare a cured film of the photosensitive resin composition. The surface of the obtained cured film was observed and judged.
◯: Clear line width / space width = 100/100 μm photosensitive pattern is drawn on the polyimide film surface, no line shaking occurs due to peeling of the line part, and there is no residual residue in the space part thing.
Δ: A clear photosensitive line width / space width = 100/100 μm was drawn, and the line portion was shaken due to peeling, but there was no undissolved residue in the space portion.
X: A clear line width / space width = 100/100 μm photosensitive pattern was not drawn, the line portion was peeled off, and a dissolution residue was generated in the space portion.

(Flexibility)
A flexible printed wiring board protected by a photosensitive coverlay layer was prepared in the same manner as in the above item (Preparation of coating film on flexible printed wiring board). This flexible printed wiring board was cut into a 30 mm × 10 mm strip, bent at 180 ° at 10 ° and bent 10 times, and the coating film was visually confirmed to check for cracks.
○: The cured film has no cracks Δ: The cured film has some cracks x: The cured film has cracks

(Solder heat resistance)
A flexible printed wiring board protected by a photosensitive coverlay layer was prepared in the same manner as in the above item (Preparation of coating film on flexible printed wiring board). The flexible printed wiring board was floated so that the surface coated with the cured film of the photosensitive resin composition was in contact with a solder bath completely dissolved at 260 ° C., and then pulled up 10 seconds later. The operation was performed three times, and the adhesive strength of the cured film was evaluated by a cross-cut tape method according to JIS K5400.
○ The one that does not peel off by the cross-cut tape method
△, if 95% or more of the cells remain
The case where the residual amount of the mesh was less than 80% was evaluated as x.

(Moisture resistance)
A flexible printed wiring board protected by a photosensitive coverlay layer was prepared in the same manner as in the above item (Preparation of coating film on flexible printed wiring board). A 100 V direct current was applied to both terminals of the test piece in an environmental test machine at 85 ° C. and 85% RH, and changes in the insulation resistance value and occurrence of migration were observed.
◯: A resistance value of 10 6 or more after 500 hours or more after the start of the test, and no occurrence of migration, dendrite, etc. ×: The occurrence of migration, dendrite, etc. after 500 hours or more after the start of the test.

(Warpage amount)
A flexible printed wiring board protected by a photosensitive coverlay layer was prepared in the same manner as in the above item (Preparation of coating film on flexible printed wiring board). The cured film was cut into a film having an area of 50 mm × 50 mm and placed on a smooth table so that the coating film was on the upper surface, and the warp height of the film edge was measured.

(Elastic modulus)
Evaluation of the elastic modulus of the photosensitive resin composition was carried out by applying the photosensitive resin composition to a final dry thickness of 25 μm on a polytetrafluoroethylene plate using a Baker type applicator, and at 20 ° C. at 20 ° C. After partial drying, a polyethylene terephthalate film was placed on the dry surface and exposed to 300 mJ / cm 2 of ultraviolet light. After completion of exposure, spray development was performed at a discharge pressure of 1.0 kgf / mm 2 using a solution obtained by heating a 1.0 wt% aqueous sodium carbonate solution to 30 ° C. After the development, it was washed purely and sufficiently, and then dried by heating in an oven at 170 ° C. for 60 minutes to prepare a cured film of the photosensitive resin composition. The obtained cured film was peeled off from the polytetrafluoroethylene plate and cut into 15 mm × 200 mm strips to obtain test pieces. The elastic modulus was measured according to ASTM D882.

(Glass-transition temperature)
A cured film of a photosensitive resin composition was produced on a polytetrafluoroethylene plate by the same method as in the above item (elastic modulus). The dynamic viscoelasticity of the obtained cured film was measured as follows.
Measuring instrument: DMS200 manufactured by Seiko Electronics Co., Ltd.
Sample shape: 9mm x 20mm
Profile: 20 ° C x 200 ° C 3 ° C / min
Frequency: 5Hz
The measurement was carried out with the above settings, and the temperature at which E ′ (storage modulus) and ΔE ′ / ΔT had minimum values (the temperature at which E ′ was most drastically reduced during temperature rise) was defined as the glass transition temperature.

(Comparative Example 1)
A photosensitive resin composition was prepared in the same manner as in Example 1 except that the half-esterified resin obtained in Synthesis Example 2 was used instead of the terminal tetracarboxylic acid resin obtained in Synthesis Example 1. Evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 2. Since the photopolymerization reaction was insufficient, the cured part was dissolved in a 1.0% by weight sodium carbonate aqueous solution during development. Moreover, imidation did not fully advance and the obtained photosensitive resin composition became a thing with very bad moisture-proof insulation.

(Comparative Example 2)
The same method as in Example 1 except that an acid-modified epoxy acrylate resin (manufactured by Nippon Kayaku Co., Ltd., product name ZAR-1395H) was used instead of the terminal tetracarboxylic acid resin and diamino compound obtained in Synthesis Example 1. A photosensitive resin composition was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2. A flexible printed wiring board with a high elastic modulus after curing as a film and a wiring pattern protected by a cured film obtained from a photosensitive resin composition has poor flexibility, has a very large warp, and is rounded into a cylindrical shape. It was.

Claims (3)

  A flexible printed wiring board in which a wiring pattern formed on at least one surface is protected by a photosensitive coverlay layer, wherein the flexible printed wiring board has a warpage amount of 2 mm or less, and the photosensitive coverlay layer is formed as a film. A flexible printed wiring board, which is a cured film obtained from a photosensitive resin composition having an elastic modulus at 25 ° C. of 10 to 1000 MPa and a glass transition temperature of 60 to 120 ° C. after curing.   A photosensitive resin composition in which the photosensitive coverlay layer contains at least (A) a terminal tetracarboxylic acid siloxane imide oligomer, (B) a diamino compound, (C) a photopolymerization initiator, and (D) a photosensitive resin. The flexible printed wiring board according to claim 1, which is a cured film obtained from the above.   3. The flexible print according to claim 1, wherein the photosensitive coverlay layer is a cured film obtained from a photosensitive coverlay ink obtained by dissolving a photosensitive resin composition in an organic solvent. Wiring board.