CN110869848A

CN110869848A - Laminated structure, dry film, and flexible printed circuit board

Info

Publication number: CN110869848A
Application number: CN201880045598.2A
Authority: CN
Inventors: 宫部英和; 内山强; 小田桐悠斗; 角谷武德
Original assignee: Taiyo Ink Mfg Co Ltd
Current assignee: Taiyo Holdings Co Ltd
Priority date: 2017-07-10
Filing date: 2018-06-26
Publication date: 2020-03-06
Also published as: KR102580790B1; JP2019015913A; KR20200027969A; JP6387444B1; WO2019012986A1; TW201908429A; TWI771439B

Abstract

Provided are a laminated structure having a bending property as high as that of the conventional one and having excellent crack resistance particularly against excessive seam folding, a dry film, and a flexible printed wiring board having a cured product thereof as a protective film. A laminated structure body, comprising: the resin layer (A) and the resin layer (B) laminated on the flexible printed circuit board with the resin layer (A) therebetween. The resin layer (B) is formed from a photosensitive thermosetting resin composition containing an alkali-soluble resin, a photopolymerization initiator, a thermally reactive compound and a block copolymer, and the resin layer (A) is formed from an alkali-developable resin composition containing an alkali-soluble resin and a thermally reactive compound.

Description

Laminated structure, dry film, and flexible printed circuit board

Technical Field

The present invention relates to a laminated structure useful as an insulating film of a flexible printed wiring board, a dry film, and a flexible printed wiring board (hereinafter, also simply referred to as "wiring board").

Background

In recent years, with the miniaturization and thinning of electronic devices due to the spread of smart phones and tablet terminals, there is a growing need for a smaller space for a circuit board. Therefore, the flexible printed circuit board which can be stored by bending has been used in a wide range of applications, and the flexible printed circuit board is required to have a reliability as high as that of the conventional flexible printed circuit board.

In contrast, a hybrid process has been widely used in which a cover layer made of polyimide having excellent mechanical properties such as heat resistance and flexibility is used for a bent portion (bent portion) (see, for example, patent documents 1 and 2), and a photosensitive resin composition having excellent electrical insulation properties, solder heat resistance, and the like is used for an attachment portion (non-bent portion) and can be finely processed, as an insulating film for ensuring insulation reliability of a flexible printed circuit board.

That is, since a cover layer made of polyimide as a base needs to be processed by die cutting, it is not suitable for fine wiring. Therefore, for a chip mounting portion requiring fine wiring, it is necessary to partially combine and use an alkali development type photosensitive resin composition (solder resist) that can be processed by photolithography.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 62-263692

Patent document 2: japanese laid-open patent publication No. 63-110224

Disclosure of Invention

Problems to be solved by the invention

As described above, in the conventional process for manufacturing a flexible printed circuit board, a mixed mounting process of a step of attaching a cover layer and a step of forming a solder resist layer has to be employed, and there is a problem that the cost and the workability are poor.

In contrast, although studies have been made so far for applying an insulating film as a solder resist layer or an insulating film as a coverlay layer to a solder resist layer and a coverlay layer of a flexible printed circuit board, a material that can sufficiently satisfy both performance requirements of the solder resist layer and the coverlay layer against the demand for a small space of a circuit board has not been put into practical use.

Specifically, in response to a demand for a smaller space for a circuit board, when the flexible printed circuit board is stored in the device, the flexible printed circuit board with components mounted thereon is folded into a seam folded state and stored. Therefore, a load is applied to the flexible printed circuit board and the insulating film thereof in a state where the joints are folded, but in this regard, a material that can sufficiently satisfy the required performance of both the solder resist layer and the cover layer has not yet been developed in practice. Here, the seam folding means that the upper surface side of the flexible printed circuit board is bent 180 °. Thus, for flexible printed wiring boards, there is a demand for insulating films suitable for solder resists and cover lay layers, which have a bending property as high as or higher than that of the past, and which have excellent crack resistance particularly even when the joints are folded excessively.

Accordingly, a main object of the present invention is to provide a laminated structure which satisfies both of the required performances of a solder resist layer and a cover layer, has a bendability as high as that of the conventional one, and particularly has excellent crack resistance even if seam folding is excessively performed. Another object of the present invention is to provide an insulating film of a flexible printed wiring board, a laminated structure particularly suitable for a process of collectively forming a bent portion (bent portion) and a mounting portion (non-bent portion), a dry film, and a flexible printed wiring board having a cured product thereof as a protective film, for example, as a cover layer or a solder resist layer.

For solvingSolution to the problem

The present inventors have conducted extensive studies to solve the above problems, and as a result, the present invention has been completed.

That is, the laminated structure of the present invention is a laminated structure including: a resin layer (A) and a resin layer (B) laminated on a flexible printed circuit board with the resin layer (A) therebetween,

the resin layer (B) is formed from a photosensitive thermosetting resin composition containing an alkali-soluble resin, a photopolymerization initiator, a thermally reactive compound, and a block copolymer, and the resin layer (a) is formed from an alkali-developable resin composition containing an alkali-soluble resin and a thermally reactive compound.

In the layered structure of the present invention, it is preferable that the block copolymer has a structure represented by the following formula (I), and the mass average molecular weight (Mw) of the block copolymer is suitably 20,000 to 400,000.

X-Y-X(I)

(in the formula (I), X is a polymer unit having a glass transition point Tg of 0 ℃ or higher, each of which may be the same or different, and Y is a polymer unit having a glass transition point Tg of less than 0 ℃)

Further, in the laminated structure of the present invention, a photobase generator is preferably contained as a photopolymerization initiator for the resin layer (B). In the laminated structure of the present invention, it is further preferable that the resin layer (a) is formed of an alkali-developable resin composition containing no photopolymerization initiator.

The laminated structure of the present invention can be used for at least any one of a bent portion and a non-bent portion of a flexible printed wiring board, and can be used for at least any one of a cover layer, a solder resist layer, and an interlayer insulating material of a flexible printed wiring board.

In the dry film of the present invention, at least one surface of the laminate structure of the present invention is supported or protected by a film.

Further, the flexible printed wiring board of the present invention is characterized by having an insulating film using the above-described laminated structure of the present invention.

Here, for the flexible printed circuit board of the present invention, it is possible to have an insulating film formed as follows: the layer of the laminated structure of the present invention is formed on a flexible printed wiring board, patterned by light irradiation, and collectively patterned by a developing solution. In addition, it is possible to have an insulating film formed as follows: the laminate structure of the present invention is not used, and is obtained by forming a resin layer (a) and a resin layer (B) in this order on a flexible printed wiring board, patterning the resin layers by light irradiation, and collectively forming a pattern by a developer. In the present invention, the term "pattern" refers to a pattern-like cured product, i.e., an insulating film.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a laminated structure can be provided which satisfies the performance required for both a solder resist layer and a cover layer, has a bendability as high as that of the conventional one, and particularly has excellent crack resistance even if seam folding is excessively performed. Further, a laminated structure and a dry film suitable for a process of collectively forming an insulating film, particularly a bent portion (bent portion) and a mounting portion (non-bent portion), of a flexible printed wiring board, and a flexible printed wiring board having a cured product thereof as a protective film, for example, a cover lay layer or a solder resist layer, can be realized.

Drawings

Fig. 1 is a process diagram schematically showing an example of a method for manufacturing a flexible printed wiring board according to the present invention.

Fig. 2 is a process diagram schematically showing another example of the method for manufacturing a flexible printed circuit board according to the present invention.

FIG. 3 is a schematic explanatory view showing an MIT test in examples.

FIG. 4 is a schematic explanatory view showing a seam folding test in examples.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

(laminated Structure)

The laminated structure of the present invention comprises: the resin layer (A) and the resin layer (B) laminated on the flexible printed circuit board with the resin layer (A) therebetween. In the laminated structure of the present invention, the resin layer (a) and the resin layer (B) each substantially function as an adhesive layer and a protective layer. The laminated structure of the present invention has the following features: the resin layer (B) is formed from a photosensitive and thermosetting resin composition containing an alkali-soluble resin, a photopolymerization initiator, a thermally reactive compound, and a block copolymer (also referred to as "BCP"), and the resin layer (a) is formed from an alkali-developable resin composition containing an alkali-soluble resin and a thermally reactive compound.

In the present invention, the resin layer (B) on the upper layer side in the laminated structure in which 2 resin layers are laminated contains the block copolymer, whereby the flexibility as high as that of the conventional one or more, particularly, excellent crack resistance to excessive seam folding, and excellent heat resistance can be realized in a well-balanced manner.

In the laminated structure of the present invention, the resin layer (a) and the resin layer (B) are provided in this order on the flexible printed circuit board having the copper circuit formed on the flexible substrate, the resin layer (B) on the upper layer side is formed of a photosensitive and thermosetting resin composition that can be patterned by light irradiation, and the resin layer (B) and the resin layer (a) on the lower layer side can be patterned together by development even if the resin layer (a) does not contain a photopolymerization initiator.

The reason for this is because: when the resin layer (a) on the printed circuit board side does not contain a photopolymerization initiator, the resin layer (a) is usually not patterned in a single layer, but in the laminated structure of the present invention, active species such as radicals generated by the photopolymerization initiator contained in the resin layer (B) on the upper layer are diffused into the resin layer (a) directly below during exposure, and thus both layers can be simultaneously patterned.

[ resin layer (A) ]

(alkali development type resin composition)

The alkali-developable resin composition constituting the resin layer (a) may be a composition containing 1 or more functional groups of a phenolic hydroxyl group and a carboxyl group, and containing an alkali-soluble resin developable with an alkali solution and a thermally reactive compound. Preferred examples of the resin composition include a compound having a phenolic hydroxyl group, a compound having a carboxyl group, and a compound having a phenolic hydroxyl group and a carboxyl group, and known and conventional resin compositions can be used.

For example, a resin composition containing a carboxyl group-containing resin or a carboxyl group-containing photosensitive resin, a compound having an ethylenically unsaturated bond, and a thermally reactive compound, which has been conventionally used as a solder resist composition, can be cited.

Here, as the carboxyl group-containing resin or the carboxyl group-containing photosensitive resin, and the compound having an ethylenically unsaturated bond, a known and conventional compound can be used.

As the thermally reactive compound, a known and conventional compound having a functional group which can be cured by heat, such as a cyclic (thio) ether group, similar to the thermally reactive compound used in the resin layer (B) can be used.

The resin layer (a) may or may not contain a photopolymerization initiator, and examples of the photopolymerization initiator used when the resin layer (a) contains a photopolymerization initiator include the same photopolymerization initiator as used for the resin layer (B).

In the present invention, the resin layer (B) is required to contain a block copolymer, and the resin layer (a) may contain a block copolymer to such an extent that the effects of the present invention, i.e., the required performances of both the solder resist layer and the cover layer, are not impaired. In this case, the same block copolymer as that used for the resin layer (B) can be used. The amount of the block copolymer to be blended in the resin layer (a) is preferably 15 parts by mass or less, more preferably 3 parts by mass or less, per 100 parts by mass of the alkali-soluble resin, and particularly preferably the resin layer (a) does not contain the block copolymer and is contained only in the resin layer (B). When the amount of the block copolymer is 15 parts by mass or less, the developability, flexibility, crack resistance and heat resistance are not affected.

[ resin layer (B) ]

(photosensitive thermosetting resin composition)

The photosensitive thermosetting resin composition constituting the resin layer (B) contains an alkali-soluble resin, a photopolymerization initiator, a thermally reactive compound, and a block copolymer.

(alkali-soluble resin)

As the alkali-soluble resin, any of the known and conventional resins can be used as long as the resin layer (a) is used, and a carboxyl group-containing resin having at least either an imide structure or an amide structure, which is excellent in properties such as bending resistance and heat resistance, can be suitably used.

Examples of the carboxyl group-containing resin having at least one of the imide structure and the amide structure include: (1) the carboxyl group-containing resin having an imide structure and an amide structure, (2) the carboxyl group-containing resin having an imide structure and no amide structure, and (3) the carboxyl group-containing resin having an amide structure and no imide structure may be used alone or as a mixture of 2 or more kinds thereof. In the present invention, among the carboxyl group-containing resins having at least either an imide structure or an amide structure, a carboxyl group-containing resin having an imide structure or an amide structure is preferably used.

The carboxyl group-containing resin having at least either an imide structure or an amide structure may further have a phenolic hydroxyl group.

(1) Carboxyl group-containing resin having imide structure and amide structure

The carboxyl group-containing resin having an imide structure and an amide structure is preferably a polyamideimide resin, and can be obtained, for example, as follows: the imide compound is obtained by reacting a diamine containing at least a carboxyl group-containing diamine with an acid anhydride (a1) containing an acid anhydride having at least 3 carboxyl groups and 2 of which are anhydrous, and then reacting a reaction raw material containing the imide compound and a diisocyanate compound. As described later, the reaction raw material preferably contains, in addition to the imide compound and the diisocyanate compound, an anhydride (a2) having at least 3 carboxyl groups and 2 of them being anhydrous.

Here, the diamine used for the synthesis of the polyamideimide resin at least contains a diamine containing a carboxyl group, and preferably a diamine having an ether bond is used in combination.

Examples of the carboxyl group-containing diamine include diaminobenzoic acids such as 3, 5-diaminobenzoic acid, 2, 5-diaminobenzoic acid and 3, 4-diaminobenzoic acid, aminophenoxybenzoic acids such as 3, 5-bis (3-aminophenoxy) benzoic acid and 3, 5-bis (4-aminophenoxy) benzoic acid, carboxybiphenyl compounds such as 3,3 ' -methylenebis (6-aminobenzoic acid) and 3,3 ' -diamino-4, 4 ' -dicarboxybiphenyl, carboxydiphenylalkanes such as 3,3 ' -diamino-4, 4 ' -dicarboxydiphenylmethane and 3,3 ' -dicarboxydiphenyl-4, 4 ' -diaminodiphenylmethane, carboxydiphenyl ether compounds such as 3,3 ' -diamino-4, 4 ' -dicarboxydiphenyl ether, and the like, these may be used alone or in appropriate combination.

Examples of the diamine having an ether bond include polyoxyethylene diamine, polyoxypropylene diamine, and polyoxyalkylene diamine containing oxyalkylene groups having different carbon chain numbers.

The diamine having an ether bond preferably has a molecular weight of 200 to 3,000, more preferably 400 to 2,000.

Examples of the polyoxyalkylene diamines include polyoxyethylenediamines such as JEFFAMINE ED-600, ED-900, ED-2003, EDR-148 and HK-511 manufactured by HUNTSMAN, JEFFAMINE D-230, D-400, D-2000 and D-4000, polyoxypropylenediamines such as JEFFAMINE XTJ-542, XTJ533 and XTJ536, which have polytetramethyleneethylene groups. Further, as the diamine having an ether bond, 2' -bis [4- (4-aminophenoxy) phenyl ] propane may also be used.

Such a diamine may be used in combination with other diamines. As the other diamines that can be used in combination, general-purpose aliphatic diamines, aromatic diamines, and the like can be used alone or in appropriate combinations. Specific examples of the other diamines include p-phenylenediamine (PPD), 1, 3-diaminobenzene, 2, 4-toluenediamine, diamines having 1 benzene nucleus, diaminodiphenyl ethers such as 4,4 '-diaminodiphenyl ether, 3' -diaminodiphenyl ether and 3,4 '-diaminodiphenyl ether, 4' -diaminodiphenylmethane, 3 '-dimethyl-4, 4' -diaminobiphenyl, 2 '-dimethyl-4, 4' -diaminobiphenyl, 1, 3-bis (3-aminophenyl) benzene, 1, 3-bis (4-aminophenyl) benzene, 1, 3-bis [ 2- (4-aminophenyl) isopropyl ] benzene, 1, 4-bis [ 2- (3-aminophenyl) isopropyl ] benzene, 1, 4-diaminodiphenyl and the like, 3,3 '-bis (3-aminophenoxy) biphenyl, 3' -bis (4-aminophenoxy) biphenyl, 4 '-bis (3-aminophenoxy) biphenyl, 4' -bis (4-aminophenoxy) biphenyl, bis [3- (3-aminophenoxy) phenyl ] ether, bis [3- (4-aminophenoxy) phenyl ] ether, bis [4- (3-aminophenoxy) phenyl ] ether, 3 '-diamino-4, 4' -dihydroxydiphenylsulfone and other aromatic diamines, 1, 2-diaminoethane, 1, 3-diaminopropane, 1, 4-diaminobutane, 1, 5-diaminopentane, 1, 6-diaminohexane, 1, 7-diaminoheptane, 1, 5-diaminopentane, and the like, Aliphatic diamines such as 1, 8-diaminooctane.

The acid anhydride (a1) used for the synthesis of the polyamideimide resin includes an acid anhydride having at least 3 carboxyl groups, 2 of which are anhydrous. The acid anhydride includes an acid anhydride having at least one of an aromatic ring and an aliphatic ring, and examples thereof include trimellitic anhydride (benzene-1, 2, 4-tricarboxylic acid 1, 2-anhydride, TMA) and 4, 4' -oxybisphthalic anhydride which are acid anhydrides having an aromatic ring, and hydrogenated trimellitic anhydride (cyclohexane-1, 2, 4-tricarboxylic acid-1, 2-anhydride, H-TMA) which is an acid anhydride having an aliphatic ring. These acid anhydrides may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

Further, a carboxylic dianhydride may be used in combination. Examples of the carboxylic acid dianhydride include tetracarboxylic acid dianhydrides such as pyromellitic acid dianhydride and 3,3 ', 4, 4' -benzophenonetetracarboxylic acid dianhydride.

As the diisocyanate compound used for the synthesis of the polyamideimide resin, diisocyanates such as aromatic diisocyanate and isomers thereof, polymers, aliphatic diisocyanates, alicyclic diisocyanates and isomers thereof, and other general-purpose diisocyanates can be used, but are not limited thereto. In addition, these diisocyanate compounds may be used alone or in combination.

As described above, the polyamideimide resin can be obtained by reacting the reaction raw materials including the imide compound and the diisocyanate compound, and further, can contain the same acid anhydride (a2) as the acid anhydride used in obtaining the imide compound. The acid anhydride (a2) may be the same acid anhydride as the acid anhydride (a1) or a different acid anhydride. The content of the acid anhydride (a2) in the reaction raw material in this case is not particularly limited.

The polyamideimide resin described above is more preferably used in particular when a diamine containing a carboxyl group and an ether bond, and H-TMA which is alicyclic trimellitic acid are used, from the viewpoint of improvement in alkali solubility and improvement in developability. For the same reason, it is also preferable to use an aliphatic diisocyanate compound in the reaction in the 2 nd stage of the polyamideimide resin. Thus, the aliphatic chain and the alicyclic structure are effectively incorporated into the structure, and the alkali solubility can be improved without significantly degrading the properties.

As the carboxyl group-containing resin having an imide structure and an amide structure, a polyamideimide resin having a structure represented by the following general formula (1) and a structure represented by the following general formula (2) can be used.

Here, X₁Is a residue of an aliphatic diamine (a) derived from a dimer acid having 24 to 48 carbon atoms. X₂Is a residue of an aromatic diamine (b) having a carboxyl group. Each Y is independently a cyclohexane ring or an aromatic ring.

Specifically, the polyamideimide resin having such a structure may be represented by the following general formula (3).

In the general formula (3), X is a diamine residue, Y is an aromatic ring or a cyclohexane ring, and Z is a residue of a diisocyanate compound. n is a natural number.

(2) Carboxyl group-containing resin having imide structure and not having amide structure

The carboxyl group-containing resin having an imide structure and not having an amide structure is not particularly limited as long as it is a resin having a carboxyl group and an imide ring. For the synthesis of the carboxyl group-containing resin having an imide structure and not having an amide structure, a known and conventional method for introducing an imide ring into a carboxyl group-containing resin can be used. For example, a resin obtained by reacting a carboxylic anhydride component with an amine component and/or an isocyanate component is exemplified. The imidization may be performed by thermal imidization or chemical imidization, or they may be used in combination.

Examples of the carboxylic anhydride component include tetracarboxylic anhydride and tricarboxylic anhydride, but the carboxylic anhydride component is not limited to these anhydrides, and any compound having an acid anhydride group and a carboxyl group which react with an amino group and an isocyanate group may be used including derivatives thereof. These carboxylic anhydride components may be used alone or in combination.

Examples of the tetracarboxylic acid anhydride include pyromellitic dianhydride, 3-fluoropyromellitic dianhydride, 3, 6-difluoropyromellitic dianhydride, 3, 6-bis (trifluoromethyl) pyromellitic dianhydride, 3 ', 4,4 ' -benzophenonetetracarboxylic dianhydride, 3 ', 4,4 ' -biphenyltetracarboxylic dianhydride, 4,4 ' -oxydiphthalic dianhydride, 2 ' -difluoro-3, 3 ', 4,4 ' -biphenyltetracarboxylic dianhydride, 5,5 ' -difluoro-3, 3 ', 4,4 ' -biphenyltetracarboxylic dianhydride, 6,6 ' -difluoro-3, 3 ', 4,4 ' -biphenyltetracarboxylic dianhydride, 2 ', 5,5 ', 6,6 ' -hexafluoro-3, 3 ', 4,4 ' -biphenyltetracarboxylic 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', 5,5 '-tetrakis (trifluoromethyl) -3, 3', 4,4 '-biphenyltetracarboxylic dianhydride, 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' -hexa (trifluoromethyl) -3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride, 1,2,3, 4-benzenetetracarboxylic dianhydride, 3 ", 4, 4" -terphenyltetracarboxylic dianhydride, 3 '", 4, 4'" -tetrabiphenyltetracarboxylic dianhydride, 3 "", 4,4 "" -pentabiphenyltetracarboxylic dianhydride, methylene-4, 4 '-diphenyldicarboxylic dianhydride, 1-ethylidene-4, 4' -diphenyldicarboxylic dianhydride, 2-propylene-4, 4 '-diphenyldicarboxylic dianhydride, 1, 2-ethylene-4, 4' -diphenyldicarboxylic dianhydride, 1, 3-trimethylene-4, 4 '-diphenyldicarboxylic dianhydride, 1, 4-tetramethylene-4, 4' -diphenyldicarboxylic dianhydride, 1, 5-pentamethylene-4, 4 ' -diphenyldicarboxylic acid dianhydride, 2, 2-bis (3, 4-dicarboxyphenyl) -1,1,1,3,3, 3-hexafluoropropane dianhydride, difluoromethylene-4, 4 ' -diphenyldicarboxylic acid dianhydride, 1,1,2, 2-tetrafluoro-1, 2-ethylene-4, 4 ' -diphenyldicarboxylic acid dianhydride, 1,1,2,2,3, 3-hexafluoro-1, 3-trimethylene-4, 4 ' -diphenyldicarboxylic acid dianhydride, 1,1,2,2,3,3,4, 4-octafluoro-1, 4-tetramethylene-4, 4 ' -diphenyldicarboxylic acid dianhydride, 1,1,2,2,3,3,4,4,5, 5-decafluoro-1, 5-pentamethylene-4, 4 ' -diphenyldicarboxylic dianhydride, thio-4, 4 ' -diphenyldicarboxylic dianhydride, sulfonyl-4, 4 ' -diphenyldicarboxylic dianhydride, 1, 3-bis (3, 4-dicarboxyphenyl) -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-bis [3- (3, 4-dicarboxyphenoxy) phenyl ] propane dianhydride, 2-bis [4- (3, 4-dicarboxyphenoxy) phenyl ] propane dianhydride, 2-bis [3- (3, 4-dicarboxyphenoxy) phenyl ] -1,1,1,3,3, 3-hexafluoropropane dianhydride, 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-naphthalenetetracarboxylic dianhydride, 1,2,5, 6-naphthalenetetracarboxylic dianhydride, 3,4,9, 10-perylenetetracarboxylic dianhydride, 2,3,6, 7-anthracenetetracarboxylic dianhydride, 1,2,7, 8-phenanthrenetetracarboxylic dianhydride, 1,2,3, 4-butanetetracarboxylic dianhydride, 1,2,3, 4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1, 2,3, 4-tetracarboxylic dianhydride, cyclohexane-1, 2,4, 5-tetracarboxylic dianhydride, 3,3 ', 4,4 ' -dicyclohexyltetracarboxylic 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-ethylidene (ethylidene) -4,4 '-bis (cyclohexane-1, 2-dicarboxylic acid) dianhydride, 2-propylene-4, 4' -bis (cyclohexane-1, 2-dicarboxylic acid) dianhydride, 1,1,1,3,3, 3-hexafluoro-2, 2-propylene-4, 4 '-bis (cyclohexane-1, 2-dicarboxylic acid) dianhydride, oxo-4, 4' -bis (cyclohexane-1, 2-dicarboxylic acid) dianhydride, hydrogen sulfide dianhydride, and the like, Thio-4, 4 '-bis (cyclohexane-1, 2-dicarboxylic acid) dianhydride, sulfonyl-4, 4' -bis (cyclohexane-1, 2-dicarboxylic acid) dianhydride, 3 '-difluorooxy-4, 4' -diphenyldicarboxylic acid dianhydride, 5,5 '-difluorooxy-4, 4' -diphenyldicarboxylic acid dianhydride, 6,6 '-difluorooxy-4, 4' -diphenyldicarboxylic acid dianhydride, 3 ', 5, 5', 6,6 '-hexafluorooxy-4, 4' -diphenyldicarboxylic acid dianhydride, 3 '-bis (trifluoromethyl) oxy-4, 4' -diphenyldicarboxylic acid dianhydride, 5,5 '-bis (trifluoromethyl) oxy-4, 4' -diphenyldicarboxylic acid dianhydride, sulfonyl-4, 4 '-bis (cyclohexane-1, 2-dicarboxylic acid) dianhydride, 3' -difluorooxy-4, 4 '-diphenyldicarboxylic acid dianhydride, and sulfonyl-4, 4' -bis (cyclohexane, 6,6 ' -bis (trifluoromethyl) oxy-4, 4 ' -diphenyldicarboxylic dianhydride, 3 ', 5,5 ' -tetrakis (trifluoromethyl) oxy-4, 4 ' -diphenyldicarboxylic dianhydride, 3 ', 6,6 ' -tetrakis (trifluoromethyl) oxy-4, 4 ' -diphenyldicarboxylic dianhydride, 5,5 ', 6,6 ' -tetrakis (trifluoromethyl) oxy-4, 4 ' -diphenyldicarboxylic dianhydride, 3 ', 5,5 ', 6,6 ' -hexa (trifluoromethyl) oxy-4, 4 ' -diphenyldicarboxylic dianhydride, 3 ' -difluorosulfonyl-4, 4 ' -diphenyldicarboxylic dianhydride, 5,5 ' -difluorosulfonyl-4, 4 ' -diphenyldicarboxylic dianhydride, 6,6 ' -difluorosulfonyl-4, 4 ' -diphenyldicarboxylic dianhydride, 3 ', 5,5 ', 6,6 ' -hexafluorosulfonyl-4, 4 ' -diphenyldicarboxylic dianhydride, 3 ' -bis (trifluoromethyl) sulfonyl-4, 4 ' -diphenyldicarboxylic dianhydride, 5,5 ' -bis (trifluoromethyl) sulfonyl-4, 4 ' -diphenyldicarboxylic dianhydride, 6,6 ' -bis (trifluoromethyl) sulfonyl-4, 4 ' -diphenyldicarboxylic dianhydride, 3 ', 5,5 ' -tetrakis (trifluoromethyl) sulfonyl-4, 4 ' -diphenyldicarboxylic dianhydride, 3 ', 6,6 ' -tetrakis (trifluoromethyl) sulfonyl-4, 4 ' -diphenyldicarboxylic dianhydride, 5,5 ', 6,6 ' -tetrakis (trifluoromethyl) sulfonyl-4, 4 ' -diphenyldicarboxylic acid dianhydride, 3 ', 5,5 ', 6,6 ' -hexa (trifluoromethyl) sulfonyl-4, 4 ' -diphenyldicarboxylic acid dianhydride, 3 ' -difluoro-2, 2-perfluoropropylene-4, 4 ' -diphenyldicarboxylic acid dianhydride, 5,5 ' -difluoro-2, 2-perfluoropropylene-4, 4 ' -diphenyldicarboxylic acid dianhydride, 6,6 ' -difluoro-2, 2-perfluoropropylene-4, 4 ' -diphenyldicarboxylic acid dianhydride, 3 ', 5,5 ', 6,6 ' -hexafluoro-2, 2-perfluoropropylene-4, 4 ' -diphenyldicarboxylic acid dianhydride, 3 ' -bis (trifluoromethyl) -2, 2-perfluoropropylene-4, 4 '-diphenyldicarboxylic acid dianhydride, 5, 5' -bis (trifluoromethyl) -2, 2-perfluoropropylene-4, 4 '-diphenyldicarboxylic acid dianhydride, 6, 6' -difluoro-2, 2-perfluoropropylene-4, 4 '-diphenyldicarboxylic acid dianhydride, 3', 5,5 '-tetrakis (trifluoromethyl) -2, 2-perfluoropropylene-4, 4' -diphenyldicarboxylic acid dianhydride, 3 ', 6, 6' -tetrakis (trifluoromethyl) -2, 2-perfluoropropylene-4, 4 '-diphenyldicarboxylic acid dianhydride, 5, 5', 6,6 '-tetrakis (trifluoromethyl) -2, 2-perfluoropropylene-4, 4' -diphenyldicarboxylic acid dianhydride, and, 3,3 ', 5, 5', 6,6 '-hexa (trifluoromethyl) -2, 2-perfluoropropylene-4, 4' -diphenyldicarboxylic acid dianhydride, 9-phenyl-9- (trifluoromethyl) xanthene-2, 3,6, 7-tetracarboxylic acid dianhydride, 9-bis (trifluoromethyl) xanthene-2, 3,6, 7-tetracarboxylic acid dianhydride, bicyclo [ 2,2, 2] oct-7-ene-2, 3,5, 6-tetracarboxylic acid dianhydride, 9-bis [4- (3, 4-dicarboxy) phenyl ] fluorene dianhydride, 9-bis [4- (2, 3-dicarboxy) phenyl ] fluorene dianhydride, ethylene glycol bistrimellitate dianhydride, 1,2- (ethylene) bis (trimellitate anhydride), 1,3- (trimethylene) bis (trimellitic acid anhydride), 1,4- (tetramethylene) bis (trimellitic acid anhydride), 1,5- (pentamethylene) bis (trimellitic acid anhydride), 1,6- (hexamethylene) bis (trimellitic acid anhydride), 1,7- (heptamethylene) bis (trimellitic acid anhydride), 1,8- (octamethylene) bis (trimellitic acid anhydride), 1,9- (nonamethylene) bis (trimellitic acid anhydride), 1,10- (decamethylene) bis (trimellitic acid anhydride), 1,12- (dodecamethylene) bis (trimellitic acid anhydride), 1,16- (hexadecamethylene) bis (trimellitic acid anhydride), 1,18- (octadecamethylene) bis (trimellitic acid anhydride), and the like. Examples of the tricarboxylic acid anhydride include trimellitic anhydride and nuclear hydrogenated trimellitic anhydride.

As the amine component, diamines such as aliphatic diamines and aromatic diamines, polyamines such as aliphatic polyether amines, diamines having carboxylic acids, diamines having phenolic hydroxyl groups, and the like can be used, but the amine component is not limited to these amines. In addition, these amine components may be used alone or in combination.

Examples of the diamine include diamines having 1 benzene nucleus such as p-phenylenediamine (PPD), 1, 3-diaminobenzene, 2, 4-tolylenediamine, 2, 5-tolylenediamine and 2, 6-tolylenediamine, diaminodiphenyl ethers such as 4,4 '-diaminodiphenyl ether, 3' -diaminodiphenyl ether and 3,4 '-diaminodiphenyl ether, 4' -diaminodiphenylmethane, 3 '-dimethyl-4, 4' -diaminobiphenyl, 2 '-bis (trifluoromethyl) -4, 4' -diaminobiphenyl, 3 '-dimethyl-4, 4' -diaminodiphenylmethane and 3,3 ', 5, 5' -tetramethyl-4, 4 '-diaminodiphenylmethane, bis (4-aminophenyl) sulfide, 4' -diaminobenzanilide, 3 '-dichlorobenzidine, 3' -dimethylbenzidine (o-tolidine), 2 '-dimethylbenzidine (m-tolidine), 3' -dimethoxybenzidine, 2 '-dimethoxybenzidine, 3' -diaminodiphenyl ether, 3,4 '-diaminodiphenyl ether, 4' -diaminodiphenyl ether, 3 '-diaminodiphenyl sulfide, 3, 4' -diaminodiphenyl sulfide, 4 '-diaminodiphenyl sulfide, 3' -diaminodiphenyl sulfone, 3,4 ' -diaminodiphenyl sulfone, 4 ' -diaminodiphenyl sulfone, 3,3 ' -diaminobenzophenone, 3,3 ' -diamino-4, 4 ' -dichlorobenzophenone, 3,3 ' -diamino-4, 4 ' -dimethoxybenzophenone, 3,3 ' -diaminodiphenylmethane, 3,4 ' -diaminodiphenylmethane, 4 ' -diaminodiphenylmethane, 2-bis (3-aminophenyl) propane, 2-bis (4-aminophenyl) propane, 2-bis (3-aminophenyl) -1,1,1,3,3, 3-hexafluoropropane, 2-bis (4-aminophenyl) -1,1,3,3, 3-hexafluoropropane, 3-dichlorobenzophenone, 3,3 ' -diaminobenzophenone, 3,3 ' -diamino-4, 4 ' -dichlorobenzophenone, 3-bis, Diamines having 2 benzene nuclei such as 3,3 '-diaminodiphenyl sulfoxide, 3, 4' -diaminodiphenyl sulfoxide, 4 '-diaminodiphenyl sulfoxide and 3, 3' -dicarboxy-4, 4 '-diaminodiphenyl methane, 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' -diamino-4- (4-phenyl) phenoxybenzophenone, 3,3 ' -diamino-4, 4 ' -bis (4-phenylphenoxy) benzophenone, 1, 3-bis (3-aminophenylsulfide) benzene, 1, 3-bis (4-aminophenylsulfide) benzene, 1, 4-bis (4-aminophenylsulfide) 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 and the like having 3 benzene nuclei, 3 ' -bis (3-aminophenoxy) biphenyl, 3,3 ' -bis (4-aminophenoxy) biphenyl, 4 ' -bis (3-aminophenoxy) biphenyl, 4 ' -bis (4-aminophenoxy) biphenyl, bis [3- (3-aminophenoxy) phenyl ] ether, bis [3- (4-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-aminophenoxy) 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-bis [3- (3-aminophenoxy) phenyl ] propane, p-toluenesulfonate, di-N-butyl ether, di-tert-butyl ether, di-3- (4-, 2, 2-bis [3- (4-aminophenoxy) phenyl ] propane, 2-bis [4- (3-aminophenoxy) phenyl ] propane, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2-bis [3- (3-aminophenoxy) phenyl ] -1,1,1,3,3, 3-hexafluoropropane, 2-bis [3- (4-aminophenoxy) phenyl ] -1,1,1,3,3, 3-hexafluoropropane, 2-bis [4- (3-aminophenoxy) phenyl ] -1,1,1,3,3, 3-hexafluoropropane, 2-bis [4- (4-aminophenoxy) phenyl ] -1, examples of the aliphatic polyether amine include aromatic diamines such as diamines having 4 benzene nuclei, e.g., 1,3,3, 3-hexafluoropropane, 1, 4-diaminoethane, 1, 5-diaminopentane, 1, 6-diaminohexane, 1, 7-diaminoheptane, 1, 8-diaminooctane, 1, 9-diaminononane, 1, 10-diaminodecane, 1, 11-diaminoundecane, 1, 12-diaminododecane, and 1, 2-diaminocyclohexane, and aliphatic polyether amines such as ethylene glycol and/or propylene glycol-based polyamines.

Examples of the amine having a carboxyl group include diaminobenzoic acids such as 3, 5-diaminobenzoic acid, 2, 5-diaminobenzoic acid and 3, 4-diaminobenzoic acid, aminophenoxybenzoic acids such as 3, 5-bis (3-aminophenoxy) benzoic acid and 3, 5-bis (4-aminophenoxy) benzoic acid, carboxybiphenyl compounds such as 3,3 ' -diamino-4, 4 ' -dicarboxybiphenyl, 4 ' -diamino-3, 3 ' -dicarboxybiphenyl, 4 ' -diamino-2, 2 ', 5,5 ' -tetracarboxybiphenyl, 3 ' -diamino-4, 4 ' -dicarboxydiphenylmethane, and mixtures thereof, Carboxydiphenylalkanes such as carboxydiphenylmethane including 3,3 '-dicarboxy-4, 4' -diaminodiphenylmethane, 2-bis [ 3-amino-4-carboxyphenyl ] propane, 2-bis [ 4-amino-3-carboxyphenyl ] propane, 2-bis [ 3-amino-4-carboxyphenyl ] hexafluoropropane and 4,4 '-diamino-2, 2', 5,5 '-tetracarboxydiphenylmethane, 3' -diamino-4, 4 '-dicarboxydiphenyl ether, 4' -diamino-3, 3 '-dicarboxydiphenyl ether, 4' -diamino-2, 2 '-dicarboxydiphenyl ether and 4, 4' -diamino-2, carboxydiphenyl ether compounds such as 2 ', 5, 5' -tetracarboxylic diphenyl ether, 3 '-diamino-4, 4' -dicarboxydiphenyl sulfone, 4 '-diamino-3, 3' -dicarboxydiphenyl sulfone, 4 '-diamino-2, 2', and diphenyl sulfone compounds such as 5, 5' -tetracarboxyldiphenyl sulfone, bis [ (carboxyphenyl) phenyl ] alkane compounds such as 2, 2-bis [4- (4-amino-3-carboxyphenoxy) phenyl ] propane, and bis [ (carboxyphenoxy) phenyl ] sulfone compounds such as 2, 2-bis [4- (4-amino-3-carboxyphenoxy) phenyl ] sulfone.

As the isocyanate component, diisocyanates such as aromatic diisocyanates and isomers thereof, polymers, aliphatic diisocyanates, alicyclic diisocyanates and isomers thereof, and other general-purpose diisocyanates can be used, but not limited to these isocyanates. In addition, these isocyanate components may be used alone or in combination.

Examples of the diisocyanate include aromatic diisocyanates such as 4, 4' -diphenylmethane diisocyanate, toluene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, biphenyl diisocyanate, diphenyl sulfone diisocyanate, and diphenyl ether diisocyanate, isomers thereof, polymers thereof, aliphatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate, alicyclic diisocyanates and isomers obtained by hydrogenating the aromatic diisocyanates, and other general-purpose diisocyanates.

(3) Carboxyl group-containing resin having amide structure and not having imide structure

The carboxyl group-containing resin having an amide structure and not having an imide structure is not particularly limited as long as it is a resin having a carboxyl group and an amide bond.

The carboxyl group-containing resin suitable for use as the alkali-soluble resin of the present invention described above preferably has an acid value of 20 to 200mgKOH/g, more preferably 60 to 150mgKOH/g, in order to cope with the photolithography step. When the acid value is 20mgKOH/g or more, solubility to alkali increases, and developability becomes good, and further, the degree of crosslinking with a thermosetting component after light irradiation becomes high, and therefore, sufficient development contrast can be obtained. On the other hand, when the acid value is 200mgKOH/g or less, accurate pattern drawing becomes easy, and particularly, so-called thermal fogging in a post exposure curing process of peb (post exposure curing) described later can be suppressed, and a process margin (process margin) becomes large.

In addition, the molecular weight of such a carboxyl group-containing resin is preferably 100,000 or less, more preferably 1,000 to 100,000, and even more preferably 2,000 to 50,000 in view of developability and cured coating film characteristics. When the molecular weight is 100,000 or less, the alkali solubility of the unexposed portion increases, and the developability improves. On the other hand, when the molecular weight is 1,000 or more, sufficient development resistance and curing properties can be obtained in the exposed portion after exposure to PEB.

(photopolymerization initiator)

As the photopolymerization initiator used in the resin layer (B), a known and conventional photopolymerization initiator can be used, and particularly, in the case of being used in the PEB step after light irradiation described later, a photopolymerization initiator having a function as a photobase generator is suitable. In the PEB step, a photopolymerization initiator and a photobase generator may be used in combination.

The photopolymerization initiator having a function as a photobase generator is a compound that generates 1 or more basic substances that can function as a catalyst for a polymerization reaction of a thermally reactive compound described later by changing a molecular structure or cleaving molecules by irradiation with light such as ultraviolet light or visible light. Examples of the basic substance include secondary amines and tertiary amines.

Examples of the photopolymerization initiator having such a function as a photobase generator include α -aminoacetophenone compound, oxime ester compound, compounds having a substituent such as an acyloxyimino group, a N-formylated aromatic amino group, an N-acylated aromatic amino group, a nitrobenzyl carbamate group, or an alkoxybenzyl carbamate group, among which oxime ester compounds and α -aminoacetophenone compounds are preferable, oxime ester compounds are more preferable, and α -aminoacetophenone compounds having 2 or more nitrogen atoms are particularly preferable.

The α -aminoacetophenone compound may be any compound having a benzoin ether bond in the molecule and being cleaved in the molecule upon exposure to light to generate an alkaline substance (amine) which functions as a curing catalyst.

The oxime ester compound may be any compound that generates a basic substance by light irradiation.

Such photopolymerization initiators may be used alone in 1 kind, or may be used in combination in 2 or more kinds. The amount of the photopolymerization initiator to be added to the resin composition is preferably 0.1 to 40 parts by mass, more preferably 0.3 to 15 parts by mass, per 100 parts by mass of the alkali-soluble resin. When the amount is 0.1 parts by mass or more, the contrast of the development resistance between the irradiated portion and the non-irradiated portion can be obtained satisfactorily. In addition, in 40 parts by mass or less, the cured product properties will be improved.

(thermally reactive Compound)

As the thermally reactive compound, a known and conventional compound having a functional group which can be cured by heat, such as a cyclic (thio) ether group, for example, an epoxy compound, can be used.

Examples of the epoxy compound include bisphenol a type epoxy resins, brominated epoxy resins, novolac type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol a type epoxy resins, glycidyl amine type epoxy resins, hydantoin type epoxy resins, alicyclic epoxy resins, trishydroxyphenylmethane type epoxy resins, bixylenol (bixylenol) type or biphenol type epoxy resins, or mixtures thereof; bisphenol S type epoxy resins, bisphenol a novolac type epoxy resins, tetrahydroxyphenyl ethane type epoxy resins, heterocyclic epoxy resins, diglycidyl phthalate resins, tetraglycidyl ditoluoyl ethane resins, naphthyl-containing epoxy resins, epoxy resins having a dicyclopentadiene skeleton, glycidyl methacrylate copolymer epoxy resins, copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate, CTBN-modified epoxy resins, and the like.

The amount of the thermally reactive compound to be blended is preferably such that the equivalent ratio to the alkali-soluble resin (alkali-soluble group such as carboxyl group: thermally reactive group such as epoxy group) is 1: 0.1-1: 10. by setting the compounding ratio in such a range, development becomes favorable, and a fine pattern can be easily formed. The equivalent ratio is more preferably 1: 0.2-1: 5.

(Block copolymer)

The block copolymer is the most characteristic component in the resin layer (B) constituting the laminated structure of the present invention in order to achieve a good balance between flexibility up to the above that of the conventional one, particularly excellent crack resistance to excessive seam folding, and excellent heat resistance.

The block copolymer generally refers to a copolymer in which two or more polymer units having different properties are linked by covalent bonds to form a long-chain molecular structure. In the present invention, as the block copolymer, a known and conventional block copolymer can be used, and an X-Y type or an X-Y-X type block copolymer is preferable, and an X-Y-X type block copolymer is more preferable. Each X in the X-Y-X type block copolymer may be the same or different.

In the X-Y type or X-Y-X type block copolymer, X is preferably a polymer unit having a glass transition point Tg of 0 ℃ or higher. More preferably, X is a polymer unit having a glass transition point Tg of 50 ℃ or higher. Y is preferably a polymer unit having a glass transition point Tg of less than 0 ℃ and more preferably a polymer unit having a glass transition point Tg of-20 ℃ or less. The glass transition point Tg is determined by Differential Scanning Calorimetry (DSC).

The block copolymer is preferably solid at 20 to 30 ℃. In this case, the temperature outside this range may be a solid as long as it is a solid within this range. When the coating composition is solid in the above temperature range, the coating composition has excellent viscosity when it is formed into a dry film or when it is applied to a substrate and temporarily dried.

In the X-Y-X type block copolymer, X is preferably highly compatible with the thermally reactive compound, and Y is preferably less compatible with the thermally reactive compound. In this way, a block copolymer is produced in which the blocks at both ends are compatible with the matrix and the block at the center is incompatible with the matrix, thereby easily exhibiting a specific structure in the matrix.

The polymer unit X is preferably polymethyl methacrylate (PMMA), Polystyrene (PS), or the like, and the polymer unit Y is preferably poly (n-butyl (meth) acrylate (PBA), Polybutadiene (PB), or the like. Further, when a hydrophilic unit having excellent compatibility with the alkali-soluble resin, such as a styrene unit, a hydroxyl group-containing unit, a carboxyl group-containing unit, an epoxy group-containing unit, or an N-substituted acrylamide unit, is introduced into a part of the polymer unit X, the compatibility can be further improved. It is particularly preferable to introduce an epoxy group-containing unit into a part of the polymer unit X. Among the above, the polymer unit X is preferably polystyrene, polyglycidyl methacrylate, N-substituted polyacrylamide, poly (meth) acrylic acid methyl ester, or a carboxylic acid-modified or hydrophilic group-modified product thereof. Y is preferably poly-n-butyl (meth) acrylate, polybutadiene or the like. X and Y may each be composed of 1 polymer unit, or may be composed of a polymer unit based on 2 or more components.

Examples of the method for producing the block copolymer include the methods described in Japanese patent publication No. 2005-515281 and Japanese patent publication No. 2007-516326.

As a commercially available product of the X-Y-X type block copolymer, an acrylic triblock copolymer produced by living polymerization, manufactured by ARKEMA K.K., can be cited. Specific examples thereof include X-Y-X type block copolymers represented by polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate (e.g., M51, M52, M53, M22, etc.), X-Y-X type block copolymers obtained by further modifying with a carboxylic acid (e.g., SM4032XM10, etc.), and X-Y-X type block copolymers obtained by modifying with a hydrophilic group (e.g., M52N, M22N, M65N, etc.).

The mass average molecular weight (Mw) of the block copolymer is usually 20,000 to 400,000, preferably 30,000 to 300,000. The molecular weight distribution (Mw/Mn) is preferably 3 or less.

When the mass average molecular weight is 20,000 or more, the composition has mechanical properties such as flexibility and elasticity, and the adhesiveness is not excessively high, and the effect of improving the bendability and the crack resistance is good and the tackiness is also good. On the other hand, when the mass average molecular weight is 400,000 or less, the viscosity of the composition does not become too high, and the printability and the developability are not easily lowered.

The block copolymer may be used alone in 1 kind, or may be used in combination of 2 or more kinds. The amount of the block copolymer is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass, and particularly preferably 3 to 40 parts by mass, per 100 parts by mass of the alkali-soluble resin. When the amount of the block copolymer is 1 part by mass or more, the flexibility and heat resistance are improved, and when it is 60 parts by mass or less, the balance between the flexibility and heat resistance is improved.

The resin composition used for the resin layer (a) and the resin layer (B) described above may contain the following components as necessary.

(Polymer resin)

The polymer resin may be blended with a known and conventional polymer resin in addition to the block copolymer for the purpose of improving the flexibility and the touch dryness of the cured product obtained. Examples of such a polymer resin include cellulose-based, polyester-based, phenoxy resin-based polymers, polyvinyl acetal-based, polyvinyl butyral-based, polyamide-based, polyamideimide-based binder polymers, and elastomers. The polymer resin may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

(inorganic Filler)

Inorganic fillers may be added to suppress curing shrinkage of the cured product and improve properties such as adhesion and hardness. Examples of such inorganic fillers include barium sulfate, amorphous silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, alumina, aluminum hydroxide, silicon nitride, aluminum nitride, boron nitride, and noniobar silica.

(coloring agent)

The colorant may be any of known and conventional colorants such as red, blue, green, yellow, white, and black, and may be any of pigments, dyes, and pigments.

(organic solvent)

In order to prepare a resin composition and adjust the viscosity for application to a substrate or a carrier film, an organic solvent may be blended. Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. Such organic solvents may be used alone in 1 kind, or may be used in the form of a mixture of 2 or more kinds.

(other Components)

If necessary, a mercapto compound, an adhesion promoter, an antioxidant, an ultraviolet absorber, and the like may be further added. The components may be those conventionally used. Further, known and conventional additives such as a thickener, a silicone-based, fluorine-based, or polymer-based defoaming agent, a leveling agent, a silane coupling agent, and a rust preventive agent, which are known and conventional, such as fine powder silica, hydrotalcite, organic bentonite, and montmorillonite, may be blended.

The laminated structure of the present invention has excellent flexibility, and therefore can be used for at least any one of a bent portion and a non-bent portion of a flexible printed wiring board, and further can be used for at least any one of a cover layer, a solder resist layer, and an interlayer insulating material of a flexible printed wiring board.

The laminated structure of the present invention having the above-described configuration is preferably used as a dry film at least one side of which is supported or protected by a film.

(Dry film)

The dry film of the present invention can be produced, for example, as follows. That is, first, the composition constituting the resin layer (B) and the composition constituting the resin layer (a) are diluted with an organic solvent to have an appropriate viscosity, and are sequentially applied to a carrier film (support film) by a known method such as a comma coater according to a conventional method. Thereafter, the dry film including the resin layer (B) and the resin layer (a) can be formed on the carrier film by drying the film at a temperature of 50 to 130 ℃ for 1 to 30 minutes. On the dry film, a peelable cover film (protective film) may be further laminated for the purpose of preventing dust from adhering to the surface of the film. As the carrier film and the cover film, conventionally known plastic films can be suitably used, and as the cover film, a cover film having a smaller adhesive force between the resin layer and the carrier film when the cover film is peeled is preferable. The thickness of the carrier film and the cover film is not particularly limited, and is preferably selected within a range of 10 to 150 μm.

(Flexible printed Circuit Board)

The flexible printed circuit board of the present invention has an insulating film formed as follows: the layer of the laminated structure of the present invention is formed on a flexible printed circuit substrate, patterned by light irradiation, and collectively patterned by a developing solution.

(method of manufacturing Wiring Board)

The flexible printed circuit board using the laminated structure of the present invention can be manufactured according to the steps shown in the process diagram of fig. 1. Namely, the manufacturing method comprises the following steps: a step (laminating step) of forming a layer of the laminated structure of the present invention on a flexible circuit substrate on which a conductor circuit is formed; a step (exposure step) of irradiating the layer of the laminated structure with an active energy ray in a pattern; and a step (developing step) of collectively forming patterned layers of the laminated structure by alkali development of the layers of the laminated structure. Further, after the alkali development, if necessary, a further photo-curing and thermal curing (post-curing step) is performed to completely cure the layer of the laminated structure, thereby obtaining a highly reliable flexible printed circuit board.

The flexible printed circuit board using the laminated structure of the present invention may be manufactured according to the steps shown in the process diagram of fig. 2. Namely, the manufacturing method comprises the following steps: a step (laminating step) of forming a layer of the laminated structure of the present invention on a flexible circuit substrate on which a conductor circuit is formed; a step (exposure step) of irradiating the layer of the laminated structure with an active energy ray in a pattern; a step of heating the layers of the laminated structure (heating (PEB) step); and a step (developing step) of forming the patterned layer of the laminated structure by alkali development of the layer of the laminated structure. Further, after the alkali development, if necessary, a further photo-curing and thermal curing (post-curing step) is performed to completely cure the layer of the laminated structure, thereby obtaining a highly reliable flexible printed circuit board. In particular, when a carboxyl group-containing resin having at least either an imide structure or an amide structure is used for the resin layer (B), it is preferable to use the steps shown in the flowchart of fig. 2.

The respective steps shown in fig. 1 or 2 will be described in detail below.

[ laminating Process ]

In this step, a laminated structure is formed on a flexible printed circuit substrate 1 on which a conductor circuit 2 is formed, the laminated structure including: the resin layer (a) is formed of an alkali-developable resin composition containing an alkali-soluble resin or the like, and the resin layer (4) is formed of a photosensitive thermosetting resin composition containing an alkali-soluble resin or the like on the resin layer (3). Here, each resin layer constituting the laminated structure can be formed, for example, by the following method: a method in which the resin compositions constituting the resin layers 3 and 4 are sequentially applied to the wiring substrate 1 and dried to form the resin layers 3 and 4, or the resin compositions constituting the resin layers 3 and 4 are laminated on the wiring substrate 1 in the form of a dry film having a 2-layer structure.

The method for coating the wiring substrate with the resin composition may be a known method such as a blade coater, a lip coater, a comma coater, or a film coater. The drying method may be a method of bringing hot air in a dryer into convective contact with each other by using a device having a heat source using a heating system of steam, such as a hot air circulation drying furnace, an IR furnace, a hot plate, or a convection oven; and a method of blowing the gas to the support body through the nozzle.

As a method for laminating the resin composition to the wiring substrate, it is preferable to use a vacuum laminator or the like for bonding under pressure and heat. By using such a vacuum laminator, even if there are irregularities on the surface of the wiring substrate, the dry film adheres to the wiring substrate, so that there is no mixing of air bubbles, and the filling property of the concave portion on the surface of the wiring substrate is improved. The pressurizing condition is preferably about 0.1 to 2.0MPa, and the heating condition is preferably 40 to 120 ℃.

[ Exposure Process ]

In this step, the photopolymerization initiator contained in the resin layer 4 is activated into a negative pattern by irradiation with active energy rays, and the exposed portion is cured. When a composition of the PEB step described later is used, a photopolymerization initiator or a photobase generator having a function as a photobase generator is activated into a negative pattern to generate a base.

As the exposure machine used in this step, a direct drawing device, an exposure machine equipped with a metal halide lamp, or the like can be used. The patterned mask for exposure is a negative mask.

As the active energy ray for exposure, a laser beam or a scattered light having a maximum wavelength in the range of 350 to 450nm is preferably used. By setting the maximum wavelength to this range, the photopolymerization initiator can be efficiently activated. Further, the exposure amount varies depending on the film thickness,usually, the concentration of the water is set to 100 to 1500mJ/cm²。

[ PEB Process ]

In this step, the resin layer is heated after exposure, thereby curing the exposed portion. In this step, the resin layer (B) can be cured to the deep part by using a photopolymerization initiator having a function as a photobase generator or by using a base generated in the exposure step of the resin layer (B) formed from a composition using a combination of a photopolymerization initiator and a photobase generator. The heating temperature is, for example, 80 to 140 ℃. The heating time is, for example, 10 to 100 minutes. Since the curing of the resin composition of the present invention is, for example, a ring-opening reaction of an epoxy resin by a thermal reaction, strain and curing shrinkage can be suppressed as compared with the case of curing by a photo radical reaction.

[ developing Process ]

In this step, unexposed portions are removed by alkali development, thereby forming a negative-type patterned insulating film, particularly a cover layer and a solder resist layer. As the developing method, a known method such as dipping can be used. As the developer, an alkaline aqueous solution such as sodium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, or a tetramethylammonium hydroxide aqueous solution (TMAH), or a mixture thereof can be used.

[ post-curing step ]

This step is a step of obtaining a highly reliable coating film by completely thermally curing the insulating film after the developing step. The heating temperature is, for example, 120 ℃ to 180 ℃. The heating time is, for example, 5 minutes to 120 minutes. Before or after the post-curing, the insulating film may be further irradiated with light.

Examples

The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples and comparative examples.

< synthetic example 1: example for Synthesis of polyimide resin solution

22.4g of 3,3 '-diamino-4, 4' -dihydroxydiphenyl sulfone, 8.2g of 2,2 '-bis [4- (4-aminophenoxy) phenyl ] propane, 30g of NMP, 30g of gamma-butyrolactone, 27.9g of 4, 4' -oxydiphthalic anhydride, and 3.8g of trimellitic anhydride were put in a separable three-neck flask equipped with a stirrer, a nitrogen inlet, a fractionating tube, and a cooling tube, and stirred at 100rpm for 4 hours under a nitrogen atmosphere at room temperature. Subsequently, 20g of toluene was added thereto, and the mixture was stirred for 4 hours while distilling off toluene and water at a silicon bath temperature of 180 ℃ and 150rpm to obtain a polyimide resin solution (PI-1) having a phenolic hydroxyl group and a carboxyl group.

The acid value of the obtained resin (solid content) was 18mgKOH, Mw was 10,000, and the hydroxyl group equivalent was 390.

(examples 1 to 6 and comparative examples 1 to 4)

The materials described in examples 1 to 6 and comparative examples 1 to 4 were compounded with the component compositions described in tables 1 and 2, respectively, premixed with a mixer, and kneaded with a three-roll kneader to prepare resin compositions for forming respective resin layers. The values in the table are parts by mass of the solid content unless otherwise specified.

< formation of resin layer (A) >

A flexible printed circuit board substrate having a copper thickness of 18 μm and formed with a circuit was prepared and subjected to pretreatment using CZ-8100 from MEC Corporation. Then, the resin compositions constituting the resin layers (a) obtained in examples 1 to 6 and comparative examples 1 to 4 were applied to the pretreated flexible printed circuit substrate so that the respective thicknesses after drying became 25 μm. Thereafter, the resin layer (A) was dried at 90 ℃ for 30 minutes in a hot air circulation drying furnace to form a resin layer (A).

< formation of resin layer (B) >

The resin compositions constituting the resin layers (B) obtained in examples 1 to 6 and comparative examples 1 to 4 were applied to the resin layer (A) formed as described above so that the respective dried films had a thickness of 10 μm. Thereafter, the resin layer (B) was dried at 90 ℃ for 30 minutes in a hot air circulation drying furnace to form a resin layer (B).

In this way, an uncured laminated structure including the resin layers (a) and (B) described in examples 1 to 6 and comparative examples 1 to 4 was formed on the flexible printed circuit substrate.

< flexibility >

(preparation of test piece)

The uncured multilayer structure on each flexible printed circuit substrate on which the multilayer structure was formed as described above was first exposed to 500mJ/cm through a negative mask using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp²A blanket exposure is performed. Thereafter, the PEB process was carried out at 90 ℃ for 30 minutes, followed by development for 60 seconds (30 ℃, 0.2MPa, 1 mass% Na)₂CO₃Aqueous solution) at 150 ℃ for 60 minutes, thereby producing a flexible printed circuit board having a cured laminated structure formed thereon.

Then, the flexible printed circuit board was cut into pieces of about 15mm × about 110mm to prepare test pieces.

(MIT test)

Specifically, as shown in fig. 3, the test piece 10 was mounted on the apparatus, the test piece 10 was vertically mounted on the jig 11 under a load F (0.5kgf), and the test piece 10 was bent at a bending angle α of 135 degrees and a speed of 175cpm, and the number of reciprocal bending times until breakage was measured (times), and it was necessary to say that the test environment was 25 ℃.

The evaluation criteria are as follows.

◎ bending the film more than 200 times without cracks in the cured film at the bent portions.

Good: bending 170-199 times, and no crack is generated.

△, bending 150-169 times, and no crack is generated.

X: cracks were generated with the number of bending times of 149 or less.

(seam folding test)

Further, the obtained test pieces were evaluated for bendability in the case of performing a seam folding test under the following excessive conditions. Specifically, as shown in fig. 4, the test piece 10 was folded by being held between 2 flat plates 12 while being bent 180 ° so that the surface X on which the conductor circuit and the cured coating film were formed was outside, and was subjected to seam folding with a load G (standard weight of 1 kg) applied for 10 seconds, and whether or not cracks were generated in the cured coating film portion 20 at the bent portion was checked using an optical microscope, and the number of times before the cracks were generated was recorded by setting the above operation to 1 cycle. The test environment was 25 ℃.

The evaluation criteria are as follows.

◎ bending the film more than 10 times without cracks in the cured film at the bent portions.

Good: the sheet was bent 6 to 9 times, and no crack was generated in the same manner.

△, no crack was generated even when the film was bent 3 to 5 times.

X: cracks were generated with the number of bending times of 2 or less.

These evaluation results are shown in tables 1 and 2.

< Heat resistance >

For the uncured laminated structure on each flexible printed circuit board substrate on which the laminated structure was formed as described above, first, using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp, an opening having a diameter of about 2mm to 5mm was formed on copper at 500mJ/cm through a negative mask having an opening having a diameter of about 2mm to 5mm²And (6) carrying out exposure. Thereafter, the PEB process was carried out at 90 ℃ for 30 minutes, followed by development for 60 seconds (30 ℃, 0.2MPa, 1 mass% Na)₂CO₃Aqueous solution) at 150 ℃ for 60 minutes, thereby producing a flexible printed circuit board (test substrate) on which a cured laminated structure is formed.

The test substrate was coated with rosin-based flux, immersed in a solder bath set at 260 ℃ and 280 ℃ for 10 seconds in advance, and the occurrence of floating, swelling, and peeling of the cured coating was evaluated.

The evaluation criteria are as follows.

◎ No floating, swelling, or peeling occurred in any of the immersion at 260 ℃ and 280 ℃.

Good: the film did not float, swell and peel when immersed at 260 ℃ but did float, swell and peel when immersed at 280 ℃.

X: the floating and peeling occurred in both of the immersion at 260 ℃ and the immersion at 280 ℃.

The evaluation results are shown in tables 1 and 2.

< resolution >

The uncured multilayer structure on each flexible printed circuit substrate on which the multilayer structure was formed as described above was first exposed to 500mJ/cm through a negative mask using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp²Pattern exposure was performed so as to form an opening having a diameter of 200 μm. Thereafter, the PEB process was performed at 90 ℃ for 30 minutes, and then development was performed at 60 seconds (30 ℃, 0.2MPa, 1 mass% Na)₂CO₃Aqueous solution), and was subjected to heat curing at 150 ℃x60 minutes to fabricate a flexible printed circuit board on which a cured laminated structure having an opening was formed. The openings formed in the laminated structure of the obtained flexible printed circuit board were observed with an optical microscope adjusted to 100 times, and the resolution was evaluated.

The evaluation criteria are as follows.

Good: the opening can be completely formed.

X: the opening cannot be formed.

The evaluation results are shown in tables 1 and 2.

[ Table 1]

1) alkali-soluble resin 1: ZAR-1035: acid-modified bisphenol A type epoxy acrylate having an acid value of 98mgKOH/g (manufactured by Nippon Kabushiki Kaisha)

2) polyimide resin: PI-1: synthesis example 1

3) photocurable monomer: BPE-500: ethoxylated bisphenol A dimethacrylate (manufactured by Xinzhongcun chemical Co., Ltd.)

4) epoxy resin: e828: bisphenol A epoxy resin, epoxy equivalent 190, mass average molecular weight 380 (Mitsubishi chemical Co., Ltd.)

5) photopolymerization initiator: IRGACURE OXE 02: oxime photopolymerization initiator (manufactured by BASF Co., Ltd.)

6) block copolymer 1: M52N: X-Y-X type block copolymer having a molecular weight (Mw) of about 100,000, manufactured by ARKEMAK K. K., NANOSTRENGTH (registered trademark)

7) block copolymer 2: M65N: X-Y-X type block copolymer having an average molecular weight (Mw) of about 100,000 to 300,000, manufactured by ARKEMA K.K., NANOSTRENGTH (registered trademark)

8) alkali-soluble resin 2: p7-532: urethane acrylate having an acid value of 47mgKOH/g (Kyoeisha chemical Co., Ltd.)

[ Table 2]

As is clear from the evaluation results shown in the tables, in the laminated structures of the examples, excellent performance was obtained with respect to all of flexibility, heat resistance and resolution by including the block copolymer in the resin layer (B) on the upper layer side. On the other hand, in comparative examples 1 and 2, which are single-layer structures, the bendability, particularly the excellent crack resistance against excessive seam folding, was insufficient, and in comparative example 3, which does not contain a block copolymer even in a laminated structure, good results were obtained with respect to the heat resistance, but the bendability, particularly the excellent crack resistance against excessive seam folding, was insufficient. In comparative example 4 in which only the resin layer (a) on the lower layer side of the laminated structure contains a block copolymer, good results were obtained with respect to heat resistance, but bendability, particularly excellent crack resistance to excessive seam folding, and resolution were not sufficient.

As described above, when the resin layer (B) on the upper layer side in the laminated structure in which 2 resin layers are laminated contains the block copolymer, the flexibility, particularly the excellent crack resistance and heat resistance against excessive seam folding can be improved in a well-balanced manner while maintaining the original characteristics of the photosensitive resin composition such as resolution.

Description of the reference numerals

1 Flexible printed Circuit substrate

2-conductor circuit

3 resin layer

4 resin layer

5 mask

10 test piece

11 clamping apparatus

12 flat plate

20 curing the coating film part

X-conductor circuit and surface of cured coating film

Claims

1. A laminated structure body is characterized by comprising: a resin layer (A) and a resin layer (B) laminated on a flexible printed circuit board with the resin layer (A) therebetween,

the resin layer (B) is formed from a photosensitive thermosetting resin composition containing an alkali-soluble resin, a photopolymerization initiator, a thermally reactive compound and a block copolymer, and the resin layer (A) is formed from an alkali-developable resin composition containing an alkali-soluble resin and a thermally reactive compound.

2. The laminated structure body according to claim 1, wherein the block copolymer has a structure represented by the following formula (I),

X-Y-X(I)

in the formula (I), X is a polymer unit having a glass transition point Tg of 0 ℃ or higher, each of which is optionally the same or different, and Y is a polymer unit having a glass transition point Tg of less than 0 ℃.

3. The laminated structure body according to claim 1, wherein the mass average molecular weight (Mw) of the block copolymer is 20000 to 400000.

4. The laminate structure according to claim 1, wherein a photobase generator is contained as a photopolymerization initiator of the resin layer (B).

5. The laminated structure according to claim 1, wherein the resin layer (a) is formed of an alkali-developable resin composition containing no photopolymerization initiator.

6. The laminate structure according to claim 1, which is used for at least one of a bent portion and a non-bent portion of a flexible printed circuit board.

7. The laminated structure body according to claim 1, which is used for at least any one of a cover layer, a solder resist layer, and an interlayer insulating material of a flexible printed circuit board.

8. A dry film characterized in that at least one side of the laminate structure of claim 1 is supported or protected by a film.

9. A flexible printed wiring board characterized by having an insulating film using the laminated structure body according to claim 1.