JP6488069B2 - Photosensitive thermosetting resin composition and flexible printed wiring board - Google Patents

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 an alkali-soluble resin having an imide ring, a photobase generator, and a thermosetting component can solve the above problems.
That is, the photobase generator is activated by light irradiation, and an alkali-soluble resin having an imide ring and a thermosetting component are subjected to an addition reaction by heating using the generated base as a catalyst, so that only an unexposed portion is removed with an alkali 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, in addition to the above-mentioned characteristics, workability is improved by using a photosensitive thermosetting resin composition containing an alkali-soluble resin in addition to an alkali-soluble resin having an imide ring, a photobase generator and a thermosetting component. An excellent photosensitive thermosetting resin composition can be obtained.

The present invention includes the following [1] to [7].
[1] A photosensitive thermosetting resin composition comprising an alkali-soluble resin having an imide ring, an alkali-soluble resin, a photobase generator, and a thermosetting component.
[2] The photosensitive thermosetting of [1], wherein the alkali-soluble resin has at least one of a urethane bond, a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, and a biphenyl skeleton in the structure. Resin composition.
[3] The photosensitive thermosetting of [1] or [2], wherein the content of the alkali-soluble resin is 10 to 70 parts by mass with respect to 100 parts by mass of the alkali-soluble resin having an imide ring. Resin composition.
[4] The photosensitive thermosetting resin composition according to any one of [1] to [3], wherein the thermosetting component is a compound having any one or more of a cyclic ether group and a cyclic thioether group. object.
[5] Any one of dry films [6] [1] to [4], which is formed by applying and drying the photosensitive thermosetting resin composition according to any one of [1] to [4] A cured coating film obtained by curing a photosensitive thermosetting resin composition or a dry film obtained by applying and drying the composition.
[7] It has a cured coating film obtained by curing a photosensitive thermosetting resin composition according to any one of [1] to [4] or a dry film formed by applying and drying the composition. Printed wiring board.

  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. 6 is a DSC chart showing the results of Reference Examples 3 and 6.

The photosensitive thermosetting resin composition of the present invention includes an alkali-soluble resin having an imide ring, an alkali-soluble resin, a photobase generator, and a thermosetting component.
The photosensitive thermosetting resin composition of the present invention causes an alkali-soluble resin having an imide ring and a thermosetting component to undergo an addition reaction by heating after exposure using a base generated from a photobase generator as a catalyst, and thereby unexposed portions. It is a resin composition that can be developed by removing the solution with an alkaline solution.
As described later, there are alkali-soluble resins other than alkali-soluble resins having an imide ring, in particular, alkali-soluble resins having any one or more of urethane bond, bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, and biphenyl skeleton. Then, compared with the case where it does not exist, it is possible to lengthen the time until it becomes alkali resistant by the addition reaction under the same heating temperature during the heat curing reaction after exposure (during the following PEB process). 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). .
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。 [Alkali-soluble resin having imide ring]
In the present invention, the alkali-soluble resin having an imide ring is a resin having an alkali-soluble group such as a carboxyl group or an acid anhydride group and an imide ring and being soluble in an alkaline solution in an uncured state.
The alkali-soluble resin having an imide ring 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 alkali-soluble resin which has an imide ring. 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 alkali-soluble resin having an imide ring 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 an alkali-soluble resin having an imide ring, a known and commonly used alkali-soluble polymer, oligomer or monomer having a carboxyl group and / or an acid anhydride group may be used. For example, these known and commonly used alkali-soluble resins may be used. Resins obtained by reacting with amines / isocyanates described above alone or in combination with the above carboxylic anhydride component may be used.

  The alkali-soluble resin having an imide ring 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.

In addition, the molecular weight of the alkali-soluble resin having an imide ring is preferably a mass average molecular weight of 1,000 to 100,000, more preferably 2,000 to 50,000 in consideration of 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.

[Alkali-soluble resin]
In the present invention, the alkali-soluble resin is an alkali-soluble resin other than the alkali-soluble resin having the imide ring. The alkali-soluble resin is a resin that has an alkali-soluble group such as a carboxyl group or an acid anhydride group and is soluble in an alkali solution in an uncured state. Preferably, the structure has one or more of a urethane bond, a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, and a biphenyl skeleton. The alkali-soluble resin having these bonds or skeletons has an imide ring because the reactivity of the carboxyl group is lower than that of the alkali-soluble resin having an imide ring and the addition reaction with the thermosetting component proceeds relatively slowly. When an alkali-soluble resin other than those is present, the heating time can be increased during the PEB process, and the range of selection of the heating temperature can be expanded during the PEB process, compared with the case where no alkali-soluble resin is present.
Moreover, it is preferable that alkali-soluble resin has an ethylenically unsaturated double bond in a molecule | numerator from the point of the improvement effect of droop generation | occurrence | production at the time of a heating. As the ethylenically unsaturated double bond, those derived from (meth) acrylic acid or (meth) acrylic acid derivatives are preferable. By having an ethylenically unsaturated double bond, when the photosensitive thermosetting resin composition of the present invention was heat-cured following development after light irradiation, the resin was dissolved by heating and formed by development. It is possible to suppress the so-called sagging that the pattern is broken.
The alkali-soluble resin of the present invention is an unexposed reaction start when it is a composition formed by mixing an alkali-soluble resin, a bisphenol A type epoxy resin having an epoxy equivalent of 190 g / eq, and an oxime ester photobase generator. The thing whose temperature is 75 degreeC or more is preferable. Specifically, an alkali-soluble resin and a bisphenol A type epoxy resin having an epoxy equivalent of about 190 g / eq (184 to 194 g / eq) are contained so that the equivalent ratio of the carboxyl group and the epoxy group is 1: 1. A composition containing 10 parts by mass of the oxime ester photobase generator with respect to 100 parts by mass of the soluble resin preferably has a reaction start temperature of 75 ° C. or higher when not exposed.
The reaction start temperature is measured in a DSC (Differential Scanning Calorimeter) measurement container so that the composition containing the alkali-soluble resin, epoxy resin and photobase generator as described above is not exposed to light. This is carried out by measuring the heat of reaction at 200 ° C. (temperature raising condition: 5 ° C./min). The temperature at the point where the suggested scanning heat becomes the minimum value in the DSC chart obtained by measuring in this way is defined as the reaction start temperature.
In the unexposed state, the reaction start temperature of the carboxyl group and the functional group that reacts with the carboxyl group in the thermosetting component is 75 ° C. or higher, so that the alkali solubility in the unexposed area in the PEB process described below is sufficient. In addition, the selection range of the heating temperature in the PEB process can be increased.

  Specific examples of the alkali-soluble resin include compounds (any of oligomers and polymers) listed below as (1) to (11).

(1) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates; carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate polyols, and polyethers A carboxyl group-containing urethane resin by a polyaddition reaction of a diol compound such as a polyol, a polyester-based polyol, a polyolefin-based polyol, an acrylic polyol, a bisphenol A-based alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.
(2) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( Photosensitive carboxyl group-containing urethane resin by polyaddition reaction of (meth) acrylate or its modified partial anhydride, carboxyl group-containing dialcohol compound and diol compound.
(3) During the synthesis of the resin of the above (1) or (2), a compound having one hydroxyl group and one or more (meth) acryl groups in a molecule such as hydroxyalkyl (meth) acrylate is added, and the terminal ( Photosensitive carboxyl group-containing urethane resin that has been meta-acrylated.
(4) During the synthesis of the resin of the above (1) or (2), one isocyanate group and one or more (meth) acryl groups are introduced into the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate. The photosensitive carboxyl group-containing urethane resin which added the compound which has and was terminally (meth) acrylated.
(5) A carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth) acrylic acid and an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth) acrylate, and isobutylene.
(6) A photosensitive carboxyl group-containing resin obtained by reacting a bifunctional or higher polyfunctional (solid) epoxy resin with (meth) acrylic acid and adding a dibasic acid anhydride to a hydroxyl group present in the side chain.
(7) Photosensitivity in which (meth) acrylic acid is reacted with a polyfunctional epoxy resin obtained by epoxidizing the hydroxyl group of a bifunctional (solid) epoxy resin with epichlorohydrin, and a dibasic acid anhydride is added to the resulting hydroxyl group. Functional carboxyl group-containing resin.
(8) A carboxyl group-containing polyester resin obtained by reacting a difunctional oxetane resin with a dicarboxylic acid and adding a dibasic acid anhydride to the resulting primary hydroxyl group.
(9) Unsaturated reaction products obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide and / or a cyclic carbonate compound such as ethylene carbonate or propylene carbonate. A carboxyl group-containing photosensitive resin obtained by partial esterification with a group-containing monocarboxylic acid and reacting the resulting reaction product with a polybasic acid anhydride.
(10) A polybasic reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide and / or a cyclic carbonate compound such as ethylene carbonate or propylene carbonate. A carboxyl group-containing resin obtained by reacting an acid anhydride.
(11) A photosensitive carboxyl group-containing resin obtained by adding a compound having one epoxy group and one or more (meth) acryl groups in one molecule to the resins (5) to (10).

The acid value of the alkali-soluble resin is preferably 20 to 200 mgKOH / g, and more preferably 40 to 150 mgKOH / g. When the acid value is within the above range, the alkali solubility is good and patterning by alkali development becomes easy.
The mass average molecular weight of the alkali-soluble resin is preferably 1,000 to 100,000, and more preferably 3,000 to 50,000. When the molecular weight is within the above range, the alkali solubility is good and patterning by alkali development becomes easy.
It is preferable that content of alkali-soluble resin is 10-70 mass parts with respect to 100 mass parts of alkali-soluble resin which has an imide ring. When the content is in the above range, the heating time can be sufficiently long during the PEB process, and the selection range of the heating temperature can be sufficiently widened during the PEB process.

[Photobase generator]
The photobase generator used in the present invention is used as a catalyst for the addition reaction of a carboxyl group and a thermosetting component described later when the molecular structure is changed by irradiation with light such as ultraviolet rays or visible light, or when the molecule is cleaved. It is a compound that produces one or more basic substances that can function. Examples of basic substances include secondary amines and tertiary amines.
When the resin composition of the present invention has an ethylenically unsaturated group in the system, it is possible to initiate a polymerization reaction of the ethylenically unsaturated group by light irradiation. Those that also function as a photo-radical polymerization initiator that generates radicals in the above process are preferred.
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-anthrylmethylN, 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 resin composition of the present invention 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. is there. 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.

[Thermosetting component]
The thermosetting component has a functional group capable of addition reaction with a carboxyl 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 a thermosetting component.

  As a compounding quantity of a thermosetting component, the equivalent ratio (a carboxyl group: thermoreactive groups, such as an epoxy group) with the alkali-soluble resin which has the said imide ring, and the said alkali-soluble resin is 1: 0.1-1: 10. Preferably there is. 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.

(Photo radical polymerization initiator)
The photosensitive thermosetting resin composition of the present invention may contain a photoradical polymerization initiator in addition to the photobase generator. As the photoradical polymerization initiator, a known photoradical polymerization initiator that generates radicals by light irradiation can be used. For example, alkylphenone photopolymerization initiators other than α-aminoacetophenone photopolymerization initiators that can function as the above-mentioned photobase generator, acylphosphine oxide photopolymerization initiators, titanocene photopolymerization initiators, etc. Can do.

(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. The inorganic filler is used for suppressing the curing shrinkage of the cured product of the resin composition and improving 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)
If necessary, the photosensitive thermosetting resin composition of the present invention may further contain components such as a photosensitive monomer, a mercapto compound, an adhesion promoter, an antioxidant, and an ultraviolet absorber. As these, those known in the field of electronic materials can be used. In addition, the above resin composition includes known and commonly used thickeners such as finely divided silica, hydrotalcite, organic bentonite, montmorillonite, silicone-based, fluorine-based, polymer-based antifoaming agents and / or leveling agents, Known and commonly used additives such as silane coupling agents and rust preventives can be blended.

[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. It may be a multi-layer dry film having a layer made of a resin composition other than 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 a photosensitive 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 photosensitive 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 photosensitive thermosetting resin composition is diluted with an organic solvent to adjust to an appropriate viscosity, and coated on 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 laminated | stacked on a resin layer. 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. After pattern exposure treatment of the resin layer, the carboxyl group in the exposed part is added and reacted with the thermoreactive functional group of the thermosetting component to develop alkali resistance, and most of the carboxyl group in the unexposed part is heated. The heating temperature is set under the condition that the alkali-solubility can be maintained by remaining without reacting with the heat-reactive functional group of the curing component. From such a viewpoint, the heating temperature is preferably 80 to 140 ° C. The heating time is preferably 10 to 100 minutes, more preferably 10 to 60 minutes, from the viewpoint of industrial mass productivity and process control.
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. Further, as the developing solution, sodium carbonate, potassium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, alkaline aqueous solution such as tetramethylammonium hydroxide aqueous solution (TMAH) or a mixed solution thereof should be used. Can do.
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 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 photocurable thermosetting resin composition containing a urethane resin having a carboxyl group, a resin having a carboxyl group, and a photobase generator.
The resin layer 4 is formed on the resin layer 3 and has an alkali-soluble resin, alkali-soluble resin, photobase generator, and thermosetting component having one or more imide rings and one or more carboxyl groups in one molecule. It consists of the photosensitive thermosetting resin composition of this invention containing this.

  In the light irradiation step of FIG. 1, a mask 5 is arranged on the resin layer 4 and light irradiation is performed in a negative pattern, thereby activating the photobase generator contained in each resin layer and curing the light irradiation portion. It is a process to do. 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.

<Synthesis example of alkali-soluble resin having imide ring>
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. Subsequently, 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 imide ring-containing alkali-soluble resin solution.

<Measurement of reaction start temperature of alkali-soluble resin>
Each alkali-soluble resin, thermosetting component (bisphenol A type epoxy resin having an epoxy equivalent of about 190 g / eq, product name: E828, manufactured by Mitsubishi Chemical Corporation), carboxyl group and epoxy group having an equivalent ratio of 1: 1 Then, 10 parts by mass of an oxime ester photobase generator (Irgacure OXE-02, manufactured by BASF) was mixed with 100 parts by mass of the alkali-soluble resin to prepare a sample. Collect 5 mg of each sample in a DSC measurement container (DSC6200 manufactured by Seiko Instruments Inc.) so as not to be exposed to light, measure the reaction heat from 25 ° C. to 200 ° C. (temperature increase 5 ° C./min), and react the carboxyl group with the epoxy group The starting temperature of the exothermic reaction was analyzed, and the minimum value of the differential scanning heat was taken as the starting temperature. The results are shown in Table 1 below. Moreover, about the measurement result of the alkali-soluble resin 3 and the alkali-soluble resin 6, a DSC chart is shown in FIG.

[Examples 1-7, Comparative Examples 1-3]
<Preparation of resin composition>
In accordance with the formulation shown in Table 2 below, the materials described in Examples and Comparative Examples were respectively blended, premixed with a stirrer, kneaded with a three-roll mill, and an alkali development type photocurable thermosetting resin composition was obtained. Prepared. The values in the table are solids (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. Then, the flexible printed wiring board which performed the said pre-processing was coated so that it might become 20 micrometers after drying the resin composition of Examples 1-7 and Comparative Examples 1-5 with the liquid application method. 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 exposed resin layer obtained by the above resin layer forming step was subjected to 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 at 90 ° C., respectively. Heat treatment was performed for minutes, 110 minutes, and 120 minutes. Thereafter, the substrate after the heat treatment is immersed in a 1% by mass sodium carbonate aqueous solution at 30 ° C., developed for 5 minutes, evaluated for developability, and the exposed portion has development resistance, that is, film thickness reduction. The time width (BA) from the heat treatment time A that was not observed to the heat treatment time B at which the unexposed area could not be completely removed by development was calculated. The greater the number, the greater the time management range of the PEB process and the better the handling.

<Developability evaluation by temperature of PEB process>
The board | substrate which has the resin layer after the exposure obtained by the formation process of said resin layer was heat-processed for 80 degreeC 60 minutes, 90 degreeC 30 minutes, and 100 degreeC 15 minutes. Thereafter, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30 ° C. and developed for 5 minutes to evaluate the possibility of pattern formation. The evaluation criteria are as follows.
OK: The exposed area shows development resistance, the unexposed area shows developability, and the pattern formation is good.
NG * 1: Pattern cannot be formed because the exposed area is dissolved in the developer.
NG * 2: The pattern cannot be formed because the unexposed area does not dissolve in the developer.

※イミド環含有アルカリ可溶性樹脂：上記イミド環を有するアルカリ可溶性樹脂の合成例にて合成したもの。酸価８６ｍｇＫＯＨ／ｇ、Ｍｗ１００００
※アルカリ可溶性樹脂１：カルボキシル基含有ポリウレタン（根上工業社製）、酸価５０ｍｇＫＯＨ／ｇ
※アルカリ可溶性樹脂２：ポリウレタンアクリレート（共栄社化学社製）、酸価４７ｍｇＫＯＨ／ｇ
※アルカリ可溶性樹脂３：ビスフェノールＦ型アクリレート樹脂（日本化薬社製）、酸価９８ｍｇＫＯＨ／ｇ
※アルカリ可溶性樹脂４：ビスフェノールＡ型アクリレート樹脂（日本化薬社製）、酸価９８ｍｇＫＯＨ／ｇ
※アルカリ可溶性樹脂５：ビフェニル型アクリレート樹脂（日本化薬社製）、酸価９８ｍｇＫＯＨ／ｇ
※アルカリ可溶性樹脂６：フェノールノボラック型アクリレート樹脂（日本化薬社製）、酸価９８ｍｇＫＯＨ／ｇ
※Ｅ８２８：ビスフェノールＡ型エポキシ樹脂（三菱化学社製）、エポキシ当量１９０ｇ／ｅｑ
※イルガキュアＯＸＥ−２：オキシムエステル系光塩基発生剤（ＢＡＳＦジャパン社製）

* Imido ring-containing alkali-soluble resin: synthesized in the above synthesis example of an alkali-soluble resin having an imide ring. Acid value 86 mgKOH / g, Mw10000
* Alkali-soluble resin 1: carboxyl group-containing polyurethane (manufactured by Negami Kogyo Co., Ltd.), acid value 50 mgKOH / g
* Alkali-soluble resin 2: Polyurethane acrylate (manufactured by Kyoeisha Chemical Co., Ltd.), acid value 47 mgKOH / g
* Alkali-soluble resin 3: bisphenol F-type acrylate resin (manufactured by Nippon Kayaku Co., Ltd.), acid value 98 mgKOH / g
* Alkali-soluble resin 4: bisphenol A acrylate resin (manufactured by Nippon Kayaku Co., Ltd.), acid value 98 mgKOH / g
* Alkali-soluble resin 5: biphenyl type acrylate resin (manufactured by Nippon Kayaku Co., Ltd.), acid value 98 mgKOH / g
* Alkali-soluble resin 6: phenol novolac acrylate resin (manufactured by Nippon Kayaku Co., Ltd.), acid value 98 mgKOH / g
* E828: bisphenol A type epoxy resin (Mitsubishi Chemical Corporation), epoxy equivalent 190 g / eq
* Irgacure OXE-2: Oxime ester photobase generator (manufactured by BASF Japan)

  As is clear from the evaluation results shown in Table 1, the photosensitive thermosetting resin compositions of Examples 1 to 7 have a large time management width in the PEB process, and are any of 80 ° C., 90 ° C., and 100 ° C. The developability was good even in the post-exposure heat treatment.

DESCRIPTION OF SYMBOLS 1 Flexible printed wiring base material 2 Copper circuit 3 Resin layer 4 Resin layer 5 Mask 6 Alkali-soluble resin 3 + Bis-A epoxy resin 7 Alkali-soluble resin 6 + Bis-A epoxy resin

Claims (3)

An alkali-soluble resin having an imide ring, an alkali-soluble resin other than the alkali-soluble resin having an imide ring, an oxime ester photobase generator, and a thermosetting component;
The alkali-soluble resin having an imide ring is a resin having an alkali-soluble group composed of a reaction product of a carboxylic anhydride component and an amine component and / or an isocyanate component,
The alkali-soluble resin other than the alkali-soluble resin having an imide ring has a carboxyl group, and further includes at least one of a urethane bond, a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, and a biphenyl skeleton in the structure. The content thereof is 10 to 70 parts by weight with respect to 100 parts by weight of the alkali-soluble resin having the imide ring,
The thermosetting component has a functional group capable of undergoing a heat addition reaction with a carboxyl group of an alkali-soluble resin other than the alkali-soluble resin having the imide ring and the alkali-soluble resin having the imide ring. to sexual resin composition,
The oxime ester-based photobase generator activated by light irradiation, a base and an alkali-soluble resins other than alkali-soluble resin having an alkali-soluble resin and the imide ring having the imide ring as a catalyst generated, the thermosetting component Is subjected to an addition reaction by heating , followed by fine processing by alkali development , and then a pattern forming method using a photosensitive thermosetting resin composition. The pattern forming method according to claim 1, wherein the thermosetting component is a compound having at least one of a cyclic ether group and a cyclic thioether group. The photosensitive thermosetting resin composition, a pattern formation method according to claim 1 or 2, wherein the resin layer constituting the dry film formed by coating and drying on the film.

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