JP2018106198A - Photosensitive thermosetting resin composition and flexible printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alkali development type thermosetting resin composition which is excellent in reliability such as impact resistance and flexibility, working accuracy and workability, and is suitable for a collective formation process of an insulating film of a flexible printed wiring board, in particular, a folded portion (bent portion) and a mounted portion (non-bent portion).SOLUTION: A photosensitive thermosetting resin composition contains (A) a polyimide resin having an imide ring and a carboxyl group, (B) a resin having a phenolic hydroxyl group, (C) a photo-base generator, and (D) a thermosetting component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photosensitive thermosetting resin composition and a flexible printed wiring board, and in particular, development with an alkali is possible, heat resistance and flexibility are excellent, and temperature and time during heat curing after light irradiation. The present invention relates to a photosensitive thermosetting resin composition that can be easily managed and a flexible printed wiring board including a cured product of the photosensitive thermosetting resin composition.

  In recent years, the spread of smartphones and tablet terminals and the improvement of performance are progressing rapidly. Information equipment terminals represented by these are highly demanded by consumers for downsizing and thinning, and in order to meet these demands, it is necessary to increase the density of circuit boards inside the products and save space. Therefore, the use of flexible printed wiring boards that can be folded and stored and that can increase the degree of freedom of circuit arrangement is expanding, and the reliability for flexible printed wiring boards is required to be higher than ever. Yes.

  Currently, a cover lay based on polyimide is used for the bent part (bent part) as an insulating film for ensuring the insulation reliability of the flexible printed wiring board, and the mounting part (non-bent part) is photosensitive. A mixed loading process using a conductive resin composition is widely employed (see Patent Documents 1 and 2). Polyimide is excellent in mechanical properties such as heat resistance and flexibility, while the photosensitive resin composition used in the mounting part has characteristics such as excellent electrical insulation and solder heat resistance and can be finely processed. .

  Conventional polyimide-based coverlays are not suitable for fine wiring because they require processing by die punching. For this reason, an alkali-developable photosensitive resin composition (solder resist) that can be processed by photolithography is partially used together in a chip mounting portion that requires fine wiring. When partially using such a resin composition in the production of a flexible printed wiring board, two processes, a process of bonding a cover lay and a process of forming a solder resist, are performed, resulting in cost and workability. There was a problem of being inferior.

Japanese Patent Application Laid-Open No. Sho 62-263692 Japanese Unexamined Patent Publication No. 63-110224

  Therefore, conventionally, an insulating film of a flexible printed wiring board that does not depend on a mixed mounting process has been studied. For example, application of a photosensitive resin composition for a solder resist as a coverlay for a flexible printed wiring board has been studied. However, in a resin composition for a solder resist, impact resistance, flexibility, etc. as a coverlay The reliability is insufficient. Since the resin composition for solder resist is accompanied by curing shrinkage due to acrylic photopolymerization, there is a problem in dimensional stability such as warping of a flexible wiring board.

  In addition, as a photosensitive polyimide that can achieve both alkali solubility and mechanical properties, a method of using a polyimide precursor and performing thermal ring closure after patterning has been proposed. However, there is a problem in workability such as requiring high-temperature treatment. It was.

  Therefore, the object of the present invention is excellent in reliability such as impact resistance and flexibility, processing accuracy, and workability. Insulating films of flexible printed wiring boards, particularly bent portions (bending portions) and mounting portions (non-bending portions). It is providing the photosensitive thermosetting resin composition suitable for a batch formation process.

As a result of intensive studies to solve the above problems, the present inventors have found that a resin composition containing a polyimide resin having a carboxyl group, a photobase generator and a thermosetting component can solve the above problems.
That is, a photobase generator is activated by light irradiation, and a polyimide resin having a carboxyl group and a thermosetting component are subjected to an addition reaction by heating using the generated base as a catalyst, whereby only an unexposed portion is removed with an alkaline solution. It has been found that this is possible. As a result, fine processing by alkali development becomes possible, and it can be expected to obtain a cured product having excellent reliability.

  On the other hand, in the heat curing reaction after light irradiation, if the range of the heating temperature and the heating time can be widened, the resin composition is more excellent in workability. The present inventors have found the following and completed the present invention. That is, a photosensitive thermosetting resin composition containing a polyimide resin having an imide ring, a carboxyl group and a phenolic hydroxyl group, or a polyimide resin having an imide ring and a carboxyl group, and a resin having a phenolic hydroxyl group. By setting it as the photosensitive thermosetting resin composition to be included, in addition to the above characteristics, a photosensitive thermosetting resin composition having more excellent workability can be obtained.

The present invention includes the following [1] to [8].
[1] A photosensitive resin comprising (A) a polyimide resin having an imide ring and a carboxyl group, (B) a resin having a phenolic hydroxyl group, (C) a photobase generator, and (D) a thermosetting component. Thermosetting resin composition.
[2] The photosensitive thermosetting resin composition according to [1], wherein the resin (B) further has an imide ring.
[3] The photosensitive thermosetting resin composition according to [2], wherein the resin (B) further has a carboxyl group.
[4] A photosensitive thermosetting resin comprising (E) a polyimide resin having an imide ring, a phenolic hydroxyl group and a carboxyl group, (C) a photobase generator, and (D) a thermosetting component. Composition.
[5] The photosensitive thermosetting resin composition according to any one of [1] to [4], wherein the thermosetting component (D) is a cyclic ether compound.
[6] The photosensitive thermosetting resin composition according to any one of [1] to [5], wherein the resin composition is for a flexible wiring board.
[7] A dry film comprising a resin layer made of the photosensitive thermosetting resin composition according to any one of [1] to [6].
[8] A printed wiring board comprising the photosensitive thermosetting resin composition according to any one of [1] to [6] or a cured product formed using the dry film according to [7].

  According to the present invention, a photosensitive thermosetting resin composition capable of developing with an alkali, excellent in heat resistance and flexibility, and easy in temperature and time management at the time of heat curing after light irradiation, and the photosensitivity It is possible to provide a dry film having a resin layer made of a thermosetting resin composition and a flexible printed wiring board provided with a cured product of the photosensitive thermosetting resin composition. The photosensitive thermosetting resin composition of the present invention is suitable for a process for forming an insulating film of a flexible printed wiring board, particularly a bent part (bent part) and a mounting part (non-bent part).

It is process drawing which shows typically an example of the manufacturing method of the flexible printed wiring board of this invention.

The first photosensitive thermosetting resin composition of the present invention comprises (A) a polyimide resin having an imide ring and a carboxyl group, (B) a resin having a phenolic hydroxyl group, (C) a photobase generator, and ( D) A thermosetting component is included. The second photosensitive thermosetting resin composition of the present invention comprises (E) a polyimide resin having an imide ring, a phenolic hydroxyl group and a carboxyl group, (C) a photobase generator, and (D) a thermosetting component. It is characterized by including.
Both can be developed by using a base generated from the photobase generator as a catalyst, causing the polyimide resin having a carboxyl group and the thermosetting component to undergo an addition reaction by heating after exposure, and removing the unexposed portion with an alkaline solution. This is common in that it is a resin composition. Any photosensitive thermosetting resin composition has a phenolic hydroxyl group in the system.
As will be described later, when a phenolic hydroxyl group is present, compared to the case where it does not exist, it becomes alkali resistance by addition reaction at the same heating temperature in the heat curing reaction after exposure (at the time of the following PEB process). The time can be lengthened. Moreover, the selection range of the heating temperature at the time of thermosetting reaction (at the time of the following PEB process) can be expanded. From these things, the workability | operativity and handleability of a resin composition improve. It is also possible to suppress the occurrence of so-called fogging in which the unexposed portion becomes resistant to alkali.

The photosensitive thermosetting resin composition of the present invention is suitable for resin insulating layers of flexible printed wiring boards, such as coverlays and solder resists.
When forming the resin insulation layer of a flexible printed wiring board using the photosensitive thermosetting resin composition of this invention, a suitable manufacturing method is as follows. That is, a step of forming a resin layer comprising the photosensitive thermosetting resin composition of the present invention on a flexible printed wiring board, a step of irradiating the resin layer with light in a pattern, and a step of heating the resin layer (Post Exposure Bake) And also referred to as PEB), and a process of alkali-developing the resin layer to form a resin insulating layer having a pattern. If necessary, after alkali development, further light irradiation or heat curing (post-cure) is performed to completely cure the resin composition to obtain a highly reliable resin insulating layer.
As described above, the photosensitive thermosetting resin composition of the present invention is preferably a negative by alkaline development by an addition reaction between a carboxyl group and a thermosetting component by selective heat treatment after light irradiation. Mold pattern formation is possible.
Since the resulting cured product is excellent in heat resistance and flexibility and can be finely processed by alkali development, it is not necessary to partially use an alkali development type photosensitive resin composition for polyimide, It can be used for both the bent part (bent part) and the mounting part (non-bent part) of the flexible printed wiring board, and is suitable for the batch formation process of the bent part (bent part) and the mounting part (non-bent part). .

  The first photosensitive thermosetting resin composition of the present invention comprises (A) a polyimide resin having an imide ring and a carboxyl group, (B) a resin having a phenolic hydroxyl group, (C) a photobase generator, and ( D) A thermosetting component is included. In addition to the polyimide resin having an imide ring and a carboxyl group, a resin having a phenolic hydroxyl group is included. As will be described later, the resin having a phenolic hydroxyl group also preferably has an imide ring, and may have a carboxyl group. Hereinafter, each component will be described in detail.

上記式（１）で表される部分構造は、下記式（２）または（３）で表されるものであることがより好ましい。

カルボキシル基の位置は特に限定されない。上記イミド環もしくはそれと結合する基の置換基としてカルボキシル基が存在してもよく、アミン成分やイソシアネート成分として、カルボキシル基を有するものを用いて合成することによってカルボキシル基をポリイミド樹脂に導入してもよい。 [(A) Polyimide resin having imide ring and carboxyl group]
In the present invention, (A) a polyimide resin having an imide ring and a carboxyl group is a resin having a carboxyl group and an imide ring.
The polyimide resin as component (A) preferably has a partial structure represented by the following formula (1) as an imide ring. In formula (1), it is preferable that R contains an aromatic ring.

The partial structure represented by the above formula (1) is more preferably one represented by the following formula (2) or (3).

The position of the carboxyl group is not particularly limited. A carboxyl group may be present as a substituent of the imide ring or a group bonded thereto, and the carboxyl group may be introduced into a polyimide resin by synthesis using an amine component or an isocyanate component having a carboxyl group. Good.

  A well-known and usual method can be used for the synthesis | combination of the polyimide resin which is (A) component. For example, the resin obtained by making a carboxylic anhydride component react with an amine component and / or an isocyanate component is mentioned. Imidization may be performed by thermal imidization, chemical imidization, or a combination thereof.

  Examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydrides and tricarboxylic acid anhydrides, but are not limited to these acid anhydrides, and acid anhydride groups that react with amino groups and isocyanate groups, and Any compound having a carboxyl group can be used, including derivatives thereof. Moreover, these carboxylic anhydride components may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the tetracarboxylic acid anhydride include pyromellitic dianhydride, 3-fluoropyromellitic dianhydride, 3,6-difluoropyromellitic dianhydride, 3,6-bis (trifluoromethyl) pyro Merit acid dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 4,4′-oxydiphthalic acid Anhydride, 2,2′-difluoro-3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 5,5′-difluoro-3,3 ′, 4,4′-biphenyltetracarboxylic acid Anhydride, 6,6′-difluoro-3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 5,5 ′, 6,6′-hexafluoro-3,3 ′ , 4,4'-biphenyltet Carboxylic dianhydride, 2,2′-bis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 5,5′-bis (trifluoromethyl) -3, 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 6,6′-bis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′ , 5,5′-tetrakis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 6,6′-tetrakis (trifluoromethyl) -3, 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 5,5 ′, 6,6′-tetrakis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride , And 2,2 ', 5,5', 6,6 -Hexakis (trifluoromethyl) -3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3 ", 4,4 "-Terphenyltetracarboxylic dianhydride, 3,3 '", 4,4' "-quaterphenyltetracarboxylic dianhydride, 3,3" ", 4,4" "-kinkphenyltetracarboxylic acid Dianhydride, methylene-4,4′-diphthalic dianhydride, 1,1-ethynylidene-4,4′-diphthalic dianhydride, 2,2-propylidene-4,4′-diphthalic dianhydride 1,2-ethylene-4,4′-diphthalic dianhydride, 1,3-trimethylene-4,4′-diphthalic dianhydride, 1,4-tetramethylene-4,4′-diphthalic acid Anhydride, 1,5-pentamethylene-4,4'-diph Talic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, difluoromethylene-4,4′-diphthal Acid dianhydride, 1,1,2,2-tetrafluoro-1,2-ethylene-4,4′-diphthalic dianhydride, 1,1,2,2,3,3-hexafluoro-1, 3-trimethylene-4,4′-diphthalic dianhydride, 1,1,2,2,3,3,4,4-octafluoro-1,4-tetramethylene-4,4′-diphthalic dianhydride 1,1,2,2,3,3,4,4,5,5-decafluoro-1,5-pentamethylene-4,4′-diphthalic dianhydride, thio-4,4′- Diphthalic dianhydride, sulfonyl-4,4′-diphthalic dianhydride, 1,3-bis (3,4-dicarboxyphene) ) -1,1,3,3-tetramethylsiloxane dianhydride, 1,3-bis (3,4-dicarboxyphenyl) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenyl) ) Benzene dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,3-bis [ 2- (3,4-Dicarboxyphenyl) -2-propyl] benzene dianhydride, 1,4-bis [2- (3,4-dicarboxyphenyl) -2-propyl] benzene dianhydride, bis [ 3- (3,4-dicarboxyphenoxy) phenyl] methane dianhydride, bis [4- (3,4-dicarboxyphenoxy) phenyl] methane dianhydride, 2,2-bis [3- (3,4- Dicarboxyphenoxy Phenyl] propane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 2,2-bis [3- (3,4-dicarboxyphenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, bis (3,4- Dicarboxyphenoxy) dimethylsilane dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) -1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalene Tetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic Acid dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid Anhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3 ′ , 4,4′-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4′-bis (cyclohexane-1, 2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethynylidene-4,4′-bis (cyclohexane) San-1,2-dicarboxylic acid) dianhydride, 2,2-propylidene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1,1,3,3,3 -Hexafluoro-2,2-propylidene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride Thio-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 3,3 ′ -Difluorooxy-4,4'-diphthalic dianhydride, 5,5'-difluorooxy-4,4'-diphthalic dianhydride, 6,6'-difluorooxy-4,4'-diphthalic acid Anhydride, 3, 3 ', 5, 5', 6 6′-hexafluorooxy-4,4′-diphthalic dianhydride, 3,3′-bis (trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 5,5′-bis (tri Fluoromethyl) oxy-4,4′-diphthalic dianhydride, 6,6′-bis (trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 3,3 ′, 5,5′- Tetrakis (trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 3,3 ′, 6,6′-tetrakis (trifluoromethyl) oxy-4,4′-diphthalic dianhydride, 5, 5 ', 6,6'-tetrakis (trifluoromethyl) oxy-4,4'-diphthalic dianhydride, 3,3', 5,5 ', 6,6'-hexakis (trifluoromethyl) oxy- 4,4'-diphthalic dianhydride, 3,3'-diflu Orosulfonyl-4,4′-diphthalic dianhydride, 5,5′-difluorosulfonyl-4,4′-diphthalic dianhydride, 6,6′-difluorosulfonyl-4,4′-diphthalic dianhydride 3,3 ′, 5,5 ′, 6,6′-hexafluorosulfonyl-4,4′-diphthalic dianhydride, 3,3′-bis (trifluoromethyl) sulfonyl-4,4′- Diphthalic dianhydride, 5,5′-bis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 6,6′-bis (trifluoromethyl) sulfonyl-4,4′-diphthalic acid Dianhydride, 3,3 ′, 5,5′-tetrakis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3 ′, 6,6′-tetrakis (trifluoromethyl) sulfonyl -4,4'-diphthalate Dianhydride, 5,5 ′, 6,6′-tetrakis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3 ′, 5,5 ′, 6,6′-hexakis ( Trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3′-difluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 5,5′-difluoro -2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 6,6'-difluoro-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 3, 3 ′, 5,5 ′, 6,6′-hexafluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 3,3′-bis (trifluoromethyl) -2, 2-perfluoropropylidene-4,4'-diphthalate Acid dianhydride, 5,5′-bis (trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 6,6′-difluoro-2,2-perfluoro Propylidene-4,4′-diphthalic dianhydride, 3,3 ′, 5,5′-tetrakis (trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride 3,3 ′, 6,6′-tetrakis (trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 5,5 ′, 6,6′-tetrakis ( Trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 3,3 ′, 5,5 ′, 6,6′-hexakis (trifluoromethyl) -2,2 -Perfluoropropylidene-4,4'-diph Talic dianhydride, 9-phenyl-9- (trifluoromethyl) xanthene-2,3,6,7-tetracarboxylic dianhydride, 9,9-bis (trifluoromethyl) xanthene-2,3 6,7-tetracarboxylic dianhydride, bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 9,9-bis [4- (3 , 4-Dicarboxy) phenyl] fluorene dianhydride, 9,9-bis [4- (2,3-dicarboxy) phenyl] fluorene dianhydride, ethylene glycol bistrimellitic dianhydride, 1,2- ( Ethylene) bis (trimellitic anhydride), 1,3- (trimethylene) bis (trimellitic anhydride), 1,4- (tetramethylene) bis (trimellitic anhydride), 1,5- (pentamethylene) bis (trimetic anhydride) Retate anhydride), 1,6- (hexamethylene) bis (trimellitic anhydride), 1,7- (heptamethylene) bis (trimellitate anhydride), 1,8- (octamethylene) bis (trimellitic anhydride), 1,9- (nonamethylene) bis (trimellitic anhydride), 1,10- (decamethylene) bis (trimellitic anhydride), 1,12- (dodecamethylene) bis (trimellitic anhydride), 1,16- (hexadeca) Methylene) bis (trimellitate anhydride), 1,18- (octadecamethylene) bis (trimellitate anhydride), and the like.

  Examples of the tricarboxylic acid anhydride include trimellitic acid anhydride and nuclear hydrogenated trimellitic acid anhydride.

  Examples of the amine component include diamines such as aliphatic diamines and aromatic diamines, and polyvalent amines such as aliphatic polyether amines, but are not limited to these amines. These amine components may be used alone or in combination.

  Examples of the diamine include one diamine nucleus diamine such as p-phenylenediamine (PPD), 1,3-diaminobenzene, 2,4-toluenediamine, 2,5-toluenediamine, and 2,6-toluenediamine. , 4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, diaminodiphenyl ethers such as 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-dimethyl-4,4′-diaminobiphenyl 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminodiphenylmethane 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylme , Bis (4-aminophenyl) sulfide, 4,4′-diaminobenzanilide, 3,3′-dichlorobenzidine, 3,3′-dimethylbenzidine (o-tolidine), 2,2′-dimethylbenzidine (m -Toridine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diamino Diphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3, 3'-diaminobenzophenone, 3,3'-diamino- , 4′-dichlorobenzophenone, 3,3′-diamino-4,4′-dimethoxybenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 2,2- Bis (3-aminophenyl) propane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 3,3′-diaminodiphenyl sulfoxide, 3,4′-diaminodiphenyl sulfoxide, 4,4 ′ -Two diamine diamines such as diaminodiphenyl sulfoxide, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane 1,3-bis (3-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (3-aminophenyl) benzene, 1,4-bis (4-aminophenyl) ) Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (3- Aminophenoxy) -4-trifluoromethylbenzene, 3,3′-diamino-4- (4-phenyl) phenoxybenzophenone, 3,3′-diamino-4,4′-di (4-phenylphenoxy) benzophenone, 1 , 3-bis (3-aminophenyl sulfide) benzene, 1,3-bis (4-aminophenyl sulfide) benzene, 1,4-bis (4-aminophenyl) Rufido) benzene, 1,3-bis (3-aminophenylsulfone) benzene, 1,3-bis (4-aminophenylsulfone) benzene, 1,4-bis (4-aminophenylsulfone) benzene, 1,3- Bis [2- (4-aminophenyl) isopropyl] benzene, 1,4-bis [2- (3-aminophenyl) isopropyl] benzene, 1,4-bis [2- (4-aminophenyl) isopropyl] benzene, etc. Benzene nucleus of three diamines, 3,3′-bis (3-aminophenoxy) biphenyl, 3,3′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 4 , 4′-bis (4-aminophenoxy) biphenyl, bis [3- (3-aminophenoxy) phenyl] ether, bis [3- ( -Aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, bis [3- (3-aminophenoxy) phenyl] ketone, Bis [3- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [3- (3-amino Phenoxy) phenyl] sulfide, bis [3- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [ 3- (3-aminophenoxy) phenyl] sulfone, bis [3- (4-aminophenoxy) ) Phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [3- (3-aminophenoxy) phenyl] methane, bis [3 -(4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 2,2-bis [3- (3- Aminophenoxy) phenyl] propane, 2,2-bis [3- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4 -(4-aminophenoxy) phenyl] propane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-he Safluoropropane, 2,2-bis [3- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (3-aminophenoxy) ) Phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexa Aromatic diamines such as four diamines of benzene nucleus such as fluoropropane, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1 It includes aliphatic diamines of 2-diaminocyclohexane, etc., the aliphatic polyether amines, polyvalent amines ethylene glycol and / or propylene glycol and the like. Moreover, the amine which has a carboxyl group can also be used as follows. Examples of the amine having a carboxyl group include 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, diaminobenzoic acids such as 3,4-diaminobenzoic acid, and 3,5-bis (3-aminophenoxy) benzoic acid. Aminophenoxybenzoic acids such as 3,5-bis (4-aminophenoxy) benzoic acid, 3,3′-diamino-4,4′-dicarboxybiphenyl, 4,4′-diamino-3,3′-di Carboxybiphenyl compounds such as carboxybiphenyl, 4,4′-diamino-2,2′-dicarboxybiphenyl, 4,4′-diamino-2,2 ′, 5,5′-tetracarboxybiphenyl, 3,3 ′ -Diamino-4,4'-dicarboxydiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 2,2-bis [3-amino-4-carbo Cyphenyl] propane, 2,2-bis [4-amino-3-carboxyphenyl] propane, 2,2-bis [3-amino-4-carboxyphenyl] hexafluoropropane, 4,4′-diamino-2,2 Carboxydiphenylalkanes such as carboxydiphenylmethane such as', 5,5'-tetracarboxydiphenylmethane, 3,3'-diamino-4,4'-dicarboxydiphenyl ether, 4,4'-diamino-3,3'-di Carboxydiphenyl ether compounds such as carboxydiphenyl ether, 4,4′-diamino-2,2′-dicarboxydiphenyl ether, 4,4′-diamino-2,2 ′, 5,5′-tetracarboxydiphenyl ether, 3,3′- Diamino-4,4′-dicarboxydiphenylsulfone, 4,4′-dia Mino-3,3′-dicarboxydiphenyl sulfone, 4,4′-diamino-2,2′-dicarboxydiphenyl sulfone, 4,4′-diamino-2,2 ′, 5,5′-tetracarboxydiphenyl sulfone Bis [(carboxyphenyl) phenyl] alkane compounds such as 2,2-bis [4- (4-amino-3-carboxyphenoxy) phenyl] propane, 2,2-bis [4- ( And bis [(carboxyphenoxy) phenyl] sulfone compounds such as 4-amino-3-carboxyphenoxy) phenyl] sulfone.

Diisocyanates such as aromatic diisocyanates and isomers and multimers, aliphatic diisocyanates, alicyclic diisocyanates and isomers thereof, and other general-purpose diisocyanates can be used as the isocyanate component. It is not limited. These isocyanate components may be used alone or in combination.
Examples of diisocyanates include aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, biphenyl diisocyanate, diphenyl sulfone diisocyanate, diphenyl ether diisocyanate, and isomers, multimers, hexamethylene diisocyanate, isophorone. Examples thereof include aliphatic diisocyanates such as diisocyanate, dicyclohexylmethane diisocyanate, and xylylene diisocyanate, alicyclic diisocyanates and isomers obtained by hydrogenation of the aromatic diisocyanate, and other general-purpose diisocyanates.

  The polyimide resin as component (A) may have an amide bond. This may be an amide bond obtained by reacting an isocyanate and a carboxylic acid, or may be caused by other reaction. Furthermore, you may have the coupling | bonding which consists of another addition and condensation.

  For the synthesis of the polyimide resin as the component (A), a publicly known and commonly used alkali-soluble polymer, oligomer or monomer having a carboxyl group and / or an acid anhydride group may be used. Resins obtained by reacting with the above amines / isocyanates alone or in combination with the above carboxylic anhydride component may also be used.

  The polyimide resin as component (A) preferably has an acid value of 20 to 200 mgKOH / g, more preferably 60 to 150 mgKOH / g in order to correspond to the alkali development step. When the acid value is 20 mgKOH / g or more, the solubility in alkali increases, the developability becomes good, and further, the degree of crosslinking with the thermosetting component after light irradiation becomes high, so that sufficient development contrast is obtained. be able to. When the acid value is 200 mgKOH / g or less, so-called heat fogging in a PEB (POST EXPOSURE BAKE) step after light irradiation described later can be suppressed, and the process margin is increased.

The molecular weight of the polyimide resin as component (A) is preferably 1,000 to 100,000, more preferably 2,000 to 50,000, considering developability and cured coating film characteristics.
When the molecular weight is 1,000 or more, sufficient development resistance and cured properties can be obtained after exposure and PEB. On the other hand, when the molecular weight is 100,000 or less, alkali solubility increases and developability improves.

[(B) Resin having phenolic hydroxyl group]
(B) The resin having a phenolic hydroxyl group is not particularly limited as long as it has a phenolic hydroxyl group in the main chain or side chain, that is, a hydroxyl group bonded to a benzene ring. Similarly to the carboxyl group, the phenolic hydroxyl group can undergo an addition reaction with the thermosetting component.
Preferably, it is a compound having two or more phenolic hydroxyl groups in one molecule.
Examples of compounds having two or more phenolic hydroxyl groups in one molecule include catechol, resorcinol, hydroquinone, dihydroxytoluene, naphthalenediol, t-butylhydroquinone, t-butylhydroquinone, pyrogallol, phloroglucinol, bisphenol A, bisphenol F. Bisphenol S, biphenol, bixylenol, novolac type phenol resin, novolac type alkylphenol resin, bisphenol A novolak resin, dicyclopentadiene type phenol resin, xylok type phenol resin, terpene modified phenol resin, polyvinylphenols, phenol Condensates of aromatics with phenolic hydroxyl groups, condensation of 1-naphthol or 2-naphthol with aromatic aldehydes Examples include, but are not limited to, compounds. These phenolic hydroxyl group-containing compounds can be used alone or in admixture of two or more.

As resin which is (B) component, what has an imide ring is preferable. Examples of the imide ring are the same as those described above. As the resin having an imide ring and a phenolic hydroxyl group, for example, a polyimide resin synthesized using a diamine having a phenolic hydroxyl group with respect to the carboxylic acid anhydride as described above is preferable. Examples of the diamine having a phenolic hydroxyl group include diaminophenols such as 2,4-diaminophenol, 3,3′-diamino-4,4′-dihydroxybiphenyl, 4,4′-diamino-3,3′-. Hydroxybiphenyl compounds such as dihydroxybiphenyl, 4,4′-diamino-2,2′-dihydroxybiphenyl, 4,4′-diamino-2,2 ′, 5,5′-tetrahydroxybiphenyl, 3,3′- Diamino-4,4′-dihydroxydiphenylmethane, 4,4′-diamino-3,3′-dihydroxydiphenylmethane, 4,4′-diamino-2,2′-dihydroxydiphenylmethane, 2,2-bis [3- Amino-4-hydroxyphenyl] propane, 2,2-bis [4-amino-3-hydroxyphenyl] propane, 2,2-bis [3-amino -4-hydroxyphenyl] hexafluoropropane, hydroxydiphenylalkanes such as hydroxydiphenylmethane such as 4,4′-diamino-2,2 ′, 5,5′-tetrahydroxydiphenylmethane, 3,3′-diamino-4, 4'-dihydroxydiphenyl ether, 4,4'-diamino-3,3'-dihydroxydiphenyl ether, 4,4'-diamino-2,2'-dihydroxydiphenyl ether, 4,4'-diamino-2,2 ', 5 Hydroxy diphenyl ether compounds such as 5′-tetrahydroxydiphenyl ether, 3,3′-diamino-4,4′-dihydroxydiphenyl sulfone, 4,4′-diamino-3,3′-dihydroxydiphenyl sulfone, 4,4′-diamino -2,2'-dihydroxydiphenylsulfone, 4,4'-di Diphenylsulfone compounds such as mino-2,2 ′, 5,5′-tetrahydroxydiphenylsulfone, and bis [(hydroxyphenyl) such as 2,2-bis [4- (4-amino-3-hydroxyphenoxy) phenyl] propane ) Phenyl] alkane compounds, bis (hydroxyphenoxy) biphenyl compounds such as 4,4′-bis (4-amino-3-hydroxyphenoxy) biphenyl, 2,2-bis [4- (4-amino- Bis [(hydroxyphenoxy) phenyl] sulfone compounds such as 3-hydroxyphenoxy) phenyl] sulfone, 4,4′-diamino-3,3′-dihydroxydiphenylmethane, 4,4′-diamino-2,2′-di Carboxydiphenylalkanes such as hydroxydiphenylmethane, 4,4′-diamino-2,2′-dihydroxy Bis (hydroxyphenoxy) biphenyl compounds such as diphenylmethane, 4,4′-bis (4-amino-3-hydroxyphenoxy) biphenyl, 1,3-bis (3-amino-4-hydroxyphenoxy) benzene, 1,3 And bis (hydroxyphenoxy) benzene compounds such as bis (4-amino-3-hydroxyphenoxy) benzene.
The molecular weight of the resin having a phenolic hydroxyl group and an imide ring is preferably a mass average molecular weight of 1,000 to 100,000, more preferably 2,000, in consideration of developability after exposure / PEB, development resistance and cured coating film characteristics. ~ 50,000 is more preferred.

[(C) Photobase generator]
(C) The photobase generator is a catalyst for an addition reaction between a polyimide resin having a carboxyl group and a thermosetting component by changing the molecular structure upon irradiation with light such as ultraviolet light or visible light, or by cleaving the molecule. Is a compound that produces one or more basic substances that can function as Examples of basic substances include secondary amines and tertiary amines.
Examples of photobase generators include α-aminoacetophenone compounds, oxime ester compounds, acyloxyimino groups, N-formylated aromatic amino groups, N-acylated aromatic amino groups, nitrobenzyl carbamate groups, and alkoxyoxybenzyl carbamates. And compounds having a substituent such as a group. Of these, oxime ester compounds and α-aminoacetophenone compounds are preferred. As the α-aminoacetophenone compound, those having two or more nitrogen atoms are particularly preferable.

  Other photobase generators include WPBG-018 (trade name: 9-anthrylmethyl N, N'-diethylcarbamate), WPBG-027 (trade name: (E) -1- [3- (2-hydroxyphenyl) -2- propenoyl] piperidine), WPBG-082 (trade name: guanidinium2- (3-benzoylphenyl) propionate), WPBG-140 (trade name: 1- (anthraquinon-2-yl) ethyl imidazolecarboxylate) and the like can also be used.

  The α-aminoacetophenone compound has a benzoin ether bond in the molecule, and when irradiated with light, cleavage occurs in the molecule to produce a basic substance (amine) that exhibits a curing catalytic action. Specific examples of the α-aminoacetophenone compound include (4-morpholinobenzoyl) -1-benzyl-1-dimethylaminopropane (Irgacure 369, trade name, manufactured by BASF Japan Ltd.) and 4- (methylthiobenzoyl) -1-methyl. -1-morpholinoethane (Irgacure 907, trade name, manufactured by BASF Japan Ltd.), 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl]- A commercially available compound such as 1-butanone (Irgacure 379, trade name, manufactured by BASF Japan Ltd.) or a solution thereof can be used.

  Any oxime ester compound can be used as long as it is a compound that generates a basic substance by light irradiation. Examples of such oxime ester compounds include CGI-325, Irgacure OXE01, Irgacure OXE02 manufactured by BASF Japan, N-1919, and NCI-831 manufactured by Adeka. Moreover, the compound which has two oxime ester groups in the molecule | numerator described in the patent 4344400 gazette can also be used suitably.

  In addition, JP-A-2004-359639, JP-A-2005-097141, JP-A-2005-220097, JP-A-2006-160634, JP-A-2008-094770, JP-A-2008-509967, Specific examples include carbazole oxime ester compounds described in JP2009-040762A and JP2011-80036A.

  Such a photobase generator may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the photobase generator in the alkali development type thermosetting resin composition is preferably 0.1 to 40 parts by mass, more preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the thermosetting component. Part by mass. In the case of 0.1 part by mass or more, the development resistance contrast of the light irradiated part / unirradiated part can be favorably obtained. Moreover, in 40 mass parts or less, hardened | cured material characteristic improves.

[(D) Thermosetting component]
(D) The thermosetting component has a functional group capable of addition reaction with a carboxyl group or a phenolic hydroxyl group by heat. As the thermosetting component, for example, a compound having a cyclic (thio) ether group is preferable, and examples thereof include an epoxy resin and a polyfunctional oxetane compound.

  The epoxy resin is a resin having an epoxy group, and any known one can be used. Examples thereof include a bifunctional epoxy resin having two epoxy groups in the molecule, and a polyfunctional epoxy resin having many epoxy groups in the molecule. In addition, a hydrogenated bifunctional epoxy compound may be used.

  Polyfunctional epoxy compounds include bisphenol A type epoxy resin, brominated epoxy resin, novolac type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, alicyclic ring Epoxy resin, trihydroxyphenylmethane type epoxy resin, bixylenol type or biphenol type epoxy resin or a mixture thereof; bisphenol S type epoxy resin, bisphenol A novolak type epoxy resin, tetraphenylolethane type epoxy resin, heterocyclic epoxy Resin, diglycidyl phthalate resin, tetraglycidyl xylenoyl ethane resin, naphthalene group-containing epoxy resin, epoxy resin having dicyclopentadiene skeleton, glycidyl meta Acrylate copolymer epoxy resins, copolymerized epoxy resins of cyclohexylmaleimide and glycidyl methacrylate, and a CTBN modified epoxy resin.

  Other liquid bifunctional epoxy resins include vinylcyclohexene diepoxide, (3 ′, 4′-epoxycyclohexylmethyl) -3,4-epoxycyclohexanecarboxylate, and (3 ′, 4′-epoxy-6′-methyl). And alicyclic epoxy resins such as (cyclohexylmethyl) -3,4-epoxy-6-methylcyclohexanecarboxylate. These epoxy resins may be used individually by 1 type, and may use 2 or more types together.

  In addition, you may mix | blend well-known and usual compounds, such as a maleimide compound, a block isocyanate compound, an amino resin, a benzoxazine resin, a carbodiimide resin, a cyclocarbonate compound, an episulfide resin, as (D) thermosetting component.

  (D) As a compounding quantity of a thermosetting component, equivalence ratio (a carboxyl group: thermoreactive groups, such as an epoxy group) with the polyimide resin which is (A) component is 1: 0.1-1: 10. Is preferred. By setting the blending ratio in such a range, development becomes favorable and a fine pattern can be easily formed. The equivalent ratio is more preferably 1: 0.2 to 1: 5.

  The second photosensitive thermosetting resin composition of the present invention comprises (E) a polyimide resin having an imide ring, a phenolic hydroxyl group and a carboxyl group, (C) a photobase generator, and (D) a thermosetting component. It is characterized by including. That is, the carboxyl group and the phenolic hydroxyl group may exist on the same resin.

[(E) Polyimide resin having imide ring, phenolic hydroxyl group and carboxyl group]
The component (E) is a polyimide resin having an imide ring, a phenolic hydroxyl group and a carboxyl group. Specific examples include those obtained by introducing a phenolic hydroxyl group into the polyimide resin as the component (A). For example, when synthesizing a polyimide resin, the component (E) can be obtained by using an amine component or an isocyanate component having a phenolic hydroxyl group in addition to a carboxyl group as a raw material.
The molecular weight of the polyimide resin as the component (E) is preferably a mass average molecular weight of 1,000 to 100,000, more preferably 2,000 to 10,000, considering developability after exposure / PEB, development resistance and cured coating film characteristics. 50,000 is more preferable.

(Polymer resin)
The photosensitive thermosetting resin composition of the present invention can be blended with conventionally known polymer resins for the purpose of improving the flexibility and dryness of the touch of the resulting cured product. Examples of the polymer resin include cellulose, polyester, phenoxy resin, polyvinyl acetal, polyvinyl butyral, polyamide, polyamideimide binder polymer, block copolymer, elastomer and the like. The above polymer resins may be used alone or in combination of two or more.

(Inorganic filler)
An inorganic filler can be blended in the photosensitive thermosetting resin composition of the present invention. An inorganic filler is used in order to suppress the curing shrinkage of the cured product of the photosensitive thermosetting resin composition and to improve properties such as adhesion and hardness. Examples of the inorganic filler include barium sulfate, amorphous silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, boron nitride, and Neuburg Examples include rich earth. The said inorganic filler may be used individually by 1 type, and may use 2 or more types together.

(Coloring agent)
Furthermore, a coloring agent can be mix | blended with the photosensitive thermosetting resin composition of this invention. As the colorant, conventionally known colorants such as red, blue, green, yellow, white, and black can be used, and any of pigments, dyes, and pigments may be used.

(Organic solvent)
In the photosensitive thermosetting resin composition of the present invention, an organic solvent can be used for preparing the resin composition and adjusting the viscosity for application to a substrate or a carrier film.
Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. Such an organic solvent may be used individually by 1 type, and may be used as a 2 or more types of mixture.

(Other optional ingredients)
The photosensitive thermosetting resin composition of the present invention may further contain components such as a photopolymerizable monomer, a mercapto compound, an adhesion promoter, an antioxidant, and an ultraviolet absorber as necessary. As these, those known in the field of electronic materials can be used. The photosensitive thermosetting resin composition includes a known and commonly used thickener such as finely divided silica, hydrotalcite, organic bentonite, and montmorillonite, an antifoaming agent such as silicone, fluorine, and polymer. // Known additives such as a leveling agent, a silane coupling agent, and a rust preventive agent can be blended.
In addition, it is preferable that the compounding quantity of a photopolymerizable monomer is 15 mass parts or less with respect to 100 mass parts of polyimide resin which is (A) component, It is more preferable that it is 10 mass parts or less, 0 mass part Most preferably (not included).

[Dry film]
The dry film of the present invention is characterized by having a resin layer comprising the photosensitive thermosetting resin composition of the present invention.
In forming a dry film, for example, the photosensitive thermosetting resin composition of the present invention is diluted with an organic solvent to adjust to an appropriate viscosity, and a uniform thickness is formed on the carrier film by a known method such as a comma coater. Apply. Thereafter, drying is usually performed at a temperature of 50 to 130 ° C. for 1 to 30 minutes to form a resin layer on the carrier film.

  A plastic film is used as the carrier film. Although there is no restriction | limiting in particular about the thickness of a carrier film, Generally, it selects suitably in the range of 10-150 micrometers. After forming the resin layer on the carrier film, a peelable cover film may be further laminated on the surface of the resin layer.

[Flexible printed wiring board and manufacturing method thereof]
The flexible printed wiring board of the present invention is characterized by having a cured product composed of a photosensitive thermosetting resin composition or a resin layer of a dry film.
The method for producing a flexible printed wiring board of the present invention includes a step of forming a resin layer made of a photosensitive thermosetting resin composition on a flexible printed wiring board, a step of irradiating the resin layer with light in a pattern, and a resin layer. A step of heating, and a step of alkali-developing the resin layer to form at least one of a coverlay and a solder resist.

[Resin layer forming step]
In this step, at least one resin layer made of an alkali development type thermosetting resin composition is formed on the flexible printed wiring board.
Examples of the method for forming the resin layer include a coating method and a laminating method.
In the case of the application method, the alkali development type thermosetting resin composition is applied onto the flexible printed wiring board by a method such as screen printing and dried to form a resin layer.
In the case of the laminating method, first, the alkali development type thermosetting resin composition is diluted with an organic solvent to adjust to an appropriate viscosity, applied onto a carrier film, and dried to prepare a dry film having a resin layer. Next, after bonding together so that a resin layer may contact a flexible printed wiring board with a laminator etc., a carrier film is peeled.

  Moreover, another layer can be interposed between the resin layer and the flexible printed wiring board. The other layer is preferably made of an alkali development type photosensitive resin composition. As an alkali development type photosensitive resin composition, a well-known composition can be used, For example, the well-known composition for coverlays or a soldering resist can be used. Thus, by setting it as the laminated structure including another layer, the hardened | cured material which was further excellent in impact resistance and flexibility can be obtained.

[Light irradiation process]
This step activates the photobase generator contained in the resin layer by light irradiation in a negative pattern to cure the light irradiation part. In this step, the photobase generator is destabilized by the base generated in the light irradiation part, and the base is chemically proliferated, whereby the resin layer can be sufficiently cured to the deep part.

As the light irradiator, a direct writer, a light irradiator equipped with a metal halide lamp, or the like can be used. The patterned light irradiation mask is a negative mask.
As the active energy ray used for light irradiation, it is preferable to use laser light or scattered light having a maximum wavelength in the range of 350 to 450 nm. By setting the maximum wavelength within this range, the photobase generator can be activated efficiently. If a laser beam in this range is used, either a gas laser or a solid laser may be used. Moreover, although the light irradiation amount changes with film thicknesses etc., it can generally be set as 100-1500 mJ / cm < ² >.

[Heating process]
In this step, after the light irradiation, the light irradiation part is cured by heating the resin layer. By this process, it is possible to cure to a deep part by the base generated in the light irradiation process. The heating temperature is, for example, 80 to 140 ° C. The heating time is, for example, 10 to 100 minutes.
Since the curing of the photosensitive thermosetting resin composition in the present invention is, for example, a ring-opening reaction of an epoxy resin by a thermal reaction, it can suppress distortion and curing shrinkage compared to the case where curing proceeds by a photoradical reaction. it can.

[Development process]
In the development step, the unirradiated portion is removed by alkali development to form a negative patterned insulating film, particularly a coverlay and a solder resist.
The developing method can be a known method such as dipping. Moreover, as a developing solution, alkaline water solution, such as potassium hydroxide, amines, tetramethylammonium hydroxide aqueous solution (TMAH), or these liquid mixture can be used.
Note that the insulating film may be further irradiated with light after the development step. For example, you may heat at 150 degreeC or more.

  Next, an example of a method for producing the flexible printed wiring board of the present invention from the photosensitive thermosetting resin composition of the present invention will be described based on the process diagram of FIG. FIG. 1 shows a case where the resin layer has a laminated structure, but it may be composed of only one layer.

In the laminating process of FIG. 1, a laminated structure composed of the resin layer 3 and the resin layer 4 is formed on the flexible printed wiring substrate 1 on which the copper circuit 2 is formed.
The resin layer 3 is made of an alkali development type photosensitive resin composition containing a carboxyl group-containing resin or the like.
The resin layer 4 is formed on the resin layer 3 and is a photosensitive heat containing a polyimide resin having one or more imide rings and one or more carboxyl groups in one molecule, a photobase generator, and a thermosetting component. It consists of a curable resin composition.

  The light irradiation process of FIG. 1 activates the photobase generator contained in the photosensitive thermosetting resin composition by disposing a mask 5 on the resin layer 4 and irradiating light in a negative pattern. This is a step of curing the light irradiation part. The heating process of FIG. 1 is a process (PEB process) of curing the light irradiation part by heating the resin layer after the light irradiation process. The development process in FIG. 1 is a process in which an unirradiated portion is removed by developing with an alkaline aqueous solution, and a negative pattern layer is formed.

  In addition, the 2nd light irradiation process of FIG. 1 is a process for activating the remaining photobase generator as needed, and generating a base, and a thermosetting process is a pattern layer as needed. This is a process for sufficient heat curing.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not restrict | limited by these Examples and a comparative example.

(Examples 1 to 3, Comparative Examples 1 and 2, Reference Examples 1 to 4)
<Synthesis example of polyimide resin solution having imide ring and carboxyl group>
In a separable three-necked flask equipped with a stirrer, nitrogen inlet tube, fractional ring, and cooling ring, 12.5 g of 3,5-diaminobenzoic acid, 2,2′-bis [4- (4-aminophenoxy) Phenyl] propane (8.2 g), NMP (30 g), γ-butyrolactone (30 g), 4,4′-oxydiphthalic anhydride (27.9 g) and trimellitic anhydride (3.8 g) were added at room temperature under a nitrogen atmosphere at 100 rpm. Stir for 4 hours. Next, 20 g of toluene was added and stirred for 4 hours while distilling off toluene and water at a silicon bath temperature of 180 ° C. and 150 rpm to obtain a polyimide resin solution (PI-1) having an imide ring and a carboxyl group.
The acid value of the obtained resin (solid content) was 85 mgKOH, and the weight average molecular weight (Mw) was 10,000.

<Synthesis example of polyimide resin solution having imide ring and phenolic hydroxyl group>
To a separable three-necked flask equipped with a stirrer, a nitrogen introduction tube, a fractionation ring, and a cooling ring, 22.4 g of 3,3′-diamino-4,4′-dihydroxydiphenylsulfone, 2,2′-bis [4 Add 8.2 g of (4-aminophenoxy) phenyl] propane, 30 g of NMP, 30 g of γ-butyrolactone, 27.9 g of 4,4′-oxydiphthalic anhydride, and 3.0 g of phthalic anhydride, and add nitrogen. It stirred at room temperature and 100 rpm for 4 hours under atmosphere. Next, 20 g of toluene was added and stirred for 4 hours while distilling off toluene and water at a silicon bath temperature of 180 ° C. and 150 rpm to obtain an alkali-soluble resin solution (PI-2) having an imide ring having an imide ring and a phenolic hydroxyl group. It was.
The obtained resin (solid content) had a hydroxyl group equivalent of 384 and Mw of 10,000.

<Synthesis example of polyimide resin solution having imide ring, phenolic hydroxyl group, carboxyl group>
To a separable three-necked flask equipped with a stirrer, a nitrogen introduction tube, a fractionation ring, and a cooling ring, 22.4 g of 3,3′-diamino-4,4′-dihydroxydiphenylsulfone, 2,2′-bis [4 -(4-aminophenoxy) phenyl] propane 8.2g, NMP 30g, γ-butyrolactone 30g, 4,4'-oxydiphthalic anhydride 27.9g, trimellitic anhydride 3.8g, The mixture was stirred at room temperature and 100 rpm for 4 hours under a nitrogen atmosphere. Next, 20 g of toluene was added and stirred for 4 hours while distilling off toluene and water at a silicon bath temperature of 180 ° C. and 150 rpm to obtain an alkali-soluble resin solution (PI-3) having an imide ring.
The acid value of the obtained resin (solid content) was 18 mgKOH, Mw was 10,000, and the hydroxyl group equivalent was 390.

<Preparation of photosensitive thermosetting resin composition>
In accordance with the formulation shown in Table 1 below, the materials described in the examples were respectively mixed, preliminarily mixed with a stirrer, and then kneaded with a three-roll mill to prepare a photosensitive thermosetting resin composition. The values in the table are parts by mass unless otherwise specified.

<Resin layer formation process>
A flexible printed wiring substrate in which a circuit was formed with a copper thickness of 18 μm was prepared, and pre-treatment was performed using MEC CZ-8100. Thereafter, the photosensitive thermosetting resin compositions of Examples 1 to 3, Comparative Examples 1 and 2, and Reference Examples 1 to 4 were dried by a liquid coating method on the pre-treated flexible printed wiring board. Coating was performed to a thickness of 10 μm. Then, it dried at 80 degreeC and 30 minutes with the hot-air circulation type drying furnace, and formed the resin layer. Thereafter, the film was irradiated with a negative pattern with an exposure amount of 500 mJ / cm ² using ORC HMW680GW (metal halide lamp, scattered light).

<Evaluation of time management width of PEB process>
The substrate having the resin layer after the exposure was subjected to heat treatment at 90 ° C. for 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, or 60 minutes, respectively. . Thereafter, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30 ° C., developed for 3 minutes, evaluated for developability, and evaluated for the width (minutes) of the developable heating time.

<Developability evaluation by temperature of PEB process>
The substrate having the exposed resin layer was heat-treated at 80 ° C. for 60 minutes, 90 ° C. for 30 minutes, and 100 ° C. for 15 minutes. Thereafter, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30 ° C. and developed for 3 minutes to evaluate the developability.
In the table: ○: Development is possible and the state of the coating film is good * 1: The pattern cannot be formed because the exposed area is dissolved in the developer.
* 2: The pattern cannot be formed because the unexposed area does not dissolve in the developer.

  The evaluation results are shown in Table 1 below.

※ 表中配合量は固形分（質量部）での数値を示す。
＊１：フェノールノボラック樹脂 水酸基当量１０６ 明和化成（株）製
＊２：ビスフェノールＡ型エポキシ樹脂 三菱化学（株）製
＊３：オキシム系光重合開始剤 ＢＡＳＦ社製

* The compounding amount in the table indicates the numerical value in terms of solid content (part by mass).
* 1: Phenol novolac resin Hydroxyl equivalent 106 Made by Meiwa Kasei Co., Ltd. * 2: Bisphenol A type epoxy resin Mitsubishi Chemical Co., Ltd. * 3: Oxime photopolymerization initiator BASF

As is clear from the evaluation results shown in Table 1, the photosensitive thermosetting resin compositions of Examples 1 to 3 can be subjected to post-exposure heat treatment at any of 80 ° C., 90 ° C., and 100 ° C. The developability was good. Moreover, from the evaluation of the PEB time management width at 90 ° C., it was confirmed that the heating time after exposure could be made longer than in the comparative example. From the above, it can be seen that the photosensitive thermosetting resin composition according to the present invention is significantly superior in the temperature controllability and time management width of the PEB process as compared with the resin compositions of Comparative Examples 1 and 2.

Claims (5)

(E) a polyimide resin having an imide ring, a phenolic hydroxyl group and a carboxyl group,
(C) a photobase generator, and
(D) thermosetting component,
A photosensitive thermosetting resin composition comprising:
The (C) photobase generator is activated by light irradiation, and the (E) polyimide resin having an imide ring, a phenolic hydroxyl group and a carboxyl group using the generated base as a catalyst, and the (D) thermosetting component, A photosensitive thermosetting resin composition characterized by being used for applications in which fine processing by alkali development is possible by addition reaction by heating.   The photosensitive thermosetting resin composition according to claim 1, wherein the thermosetting component (D) is a cyclic ether compound.   The photosensitive thermosetting resin composition according to claim 1, wherein the resin composition is for a flexible printed wiring board.   It has a resin layer which consists of a photosensitive thermosetting resin composition as described in any one of Claims 1-3, The dry film characterized by the above-mentioned. A printed wiring board comprising: the photosensitive thermosetting resin composition according to claim 1; or a cured product formed using the dry film according to claim 4.

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