KR102580790B1 - Laminated structures, dry films and flexible printed wiring boards - Google Patents

Abstract

Provided is a flexible printed wiring board having a laminated structure having higher flexibility than ever before, especially excellent crack resistance against excessive seam folding, a dry film, and a cured product thereof as a protective film. It is a laminated structure having a resin layer (A) and a resin layer (B) laminated on a flexible printed wiring board through the resin layer (A). The resin layer (B) is made of a photosensitive thermosetting resin composition containing an alkali-soluble resin, a photopolymerization initiator, a heat-reactive compound, and a block copolymer, and the resin layer (A) is made of a photosensitive thermosetting resin composition containing an alkali-soluble resin and a heat-reactive compound. It consists of an alkali-developable resin composition.

Description

Laminated structures, dry films and flexible printed wiring boards

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

In recent years, as electronic devices have become smaller and thinner due to the spread of smartphones and tablet terminals, it has become necessary to reduce the space of circuit boards. Therefore, the use of flexible printed wiring boards that can be bent and stored is expanding, and flexible printed wiring boards are also required to have higher reliability than before.

In contrast, currently, as an insulating film to ensure the insulation reliability of flexible printed wiring boards, a polyimide-based coverlay with excellent mechanical properties such as heat resistance and flexibility is used in the bent portion (for example, patented (see Documents 1 and 2), a mixed process using a photosensitive resin composition that has excellent electrical insulation and solder heat resistance and is capable of fine processing is widely adopted for the mounting portion (non-bent portion).

That is, polyimide-based coverlays are unsuitable for fine wiring because they require processing by mold punching. Therefore, it was necessary to partially use an alkaline-developable photosensitive resin composition (solder resist) that can be processed by photolithography in the chip mounting portion that requires fine wiring.

Japanese Patent Publication No. 62-263692 Japanese Patent Publication No. 63-110224

In this way, in the manufacturing process of the conventional flexible printed wiring board, a mixed process of the process of bonding the coverlay and the process of forming the solder resist must be adopted, which has the problem of poor cost and workability.

In contrast, so far, the application of an insulating film as a solder resist or an insulating film as a coverlay has been considered as a solder resist and coverlay for a flexible printed wiring board. However, in response to the demand for reducing the space of the circuit board, solder resist and coverlay have been used. Materials that can sufficiently satisfy both required performances have not yet been put into practical use.

Specifically, when storing a flexible printed wiring board in a device in response to the demand for reducing the space of the circuit board, the flexible printed wiring board on which the components are mounted is bent in a seam folded state and stored. Therefore, a load is applied to the flexible printed wiring board and its insulating film in a seam-folded state, but in this regard, the reality is that a material that can sufficiently satisfy the required performance of both solder resist and coverlay has not been developed. It was. Here, seam folding means bending the upper surface side of the flexible printed wiring board by 180°. Therefore, flexible printed wiring boards are required to have higher flexibility than ever before, especially solder resists with excellent crack resistance even when seam folded excessively, and insulating films suitable for coverlay.

Therefore, the main purpose of the present invention is to provide a laminated structure that satisfies the required performance of both solder resist and cover lay, has higher flexibility than before, and especially has excellent crack resistance even when excessively seam folded. In addition, another object of the present invention is to provide an insulating film of a flexible printed wiring board, particularly a laminated structure suitable for the batch formation process of the bent portion (bent portion) and the mounting portion (non-bent portion), a dry film, and a cured product thereof as a protective film, such as The object is to provide a flexible printed wiring board with a coverlay or solder resist.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.

That is, the laminated structure of the present invention is a laminated structure having a resin layer (A) and a resin layer (B) laminated on a flexible printed wiring board through the resin layer (A),

The resin layer (B) is made of a photosensitive thermosetting resin composition containing an alkali-soluble resin, a photopolymerization initiator, a heat-reactive compound, and a block copolymer, and the resin layer (A) is made of an alkali-soluble resin and a heat-reactive compound. It is characterized by being made of an alkali-developable resin composition containing.

In the laminated structure of the present invention, the block copolymer preferably 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 Formula (I),

Furthermore, in the laminated structure of the present invention, it is preferable to include a photobase generator as a photopolymerization initiator of the resin layer (B). Additionally, in the laminated structure of the present invention, it is preferable that the resin layer (A) consists of an alkali-developable resin composition that does not contain a photopolymerization initiator.

The laminated structure of the present invention can be used in at least one of the bent portion and the non-bent portion of a flexible printed wiring board, and can be used in at least one of the coverlay, solder resist, and interlayer insulating materials of the flexible printed wiring board.

Additionally, the dry film of the present invention is characterized in that at least one side of the laminated structure of the present invention is supported or protected by a film.

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

Here, the flexible printed wiring board of the present invention may have an insulating film formed by forming a layer of the above-mentioned laminated structure of the present invention on a flexible printed wiring board, patterning it by light irradiation, and forming the pattern all at once with a developer. In addition, without using the laminated structure according to the present invention, the resin layer (A) and the resin layer (B) are sequentially formed on a flexible printed wiring board, then patterned by light irradiation, and the patterns are formed all at once with a developer. It may have an insulating film formed by: In addition, in the present invention, “pattern” means a cured product in a pattern, that is, an insulating film.

According to the present invention, it is possible to provide a laminated structure that satisfies the required performance of both solder resist and cover lay, has higher flexibility than before, and especially has excellent crack resistance even when excessively seam folded. In addition, it has a laminated structure suitable for the batch formation process of the insulating film of a flexible printed wiring board, especially the bent part (bent part) and the mounting part (non-bent part), a dry film, and its cured product as a protective film, for example, a coverlay or solder resist. It has become possible to realize a flexible printed wiring board.

1 is a process diagram schematically showing an example of a method for manufacturing a flexible printed wiring board of the present invention.
Figure 2 is a process diagram schematically showing another example of the manufacturing method of the flexible printed wiring board of the present invention.
Figure 3 is a schematic explanatory diagram showing the MIT test in the example.
Figure 4 is a schematic diagram showing a seam folding test in an example.

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

(laminated structure)

The laminated structure of the present invention has a resin layer (A) and a resin layer (B) laminated on a flexible printed wiring board through the resin layer (A). Here, in the laminated structure of the present invention, the resin layer (A) and the resin layer (B) substantially function as an adhesive layer and a protective layer, respectively. In the laminate structure of the present invention, the resin layer (B) is made of a photosensitive thermosetting resin composition containing an alkali-soluble resin, a photopolymerization initiator, a heat-reactive compound, and a block copolymer (also referred to as "BCP"), and water The stratum (A) is characterized in that it consists of an alkali-developable resin composition containing an alkali-soluble resin and a heat-reactive compound.

In the present invention, by containing a block copolymer in the resin layer (B) on the upper layer of a laminated structure formed by laminating two resin layers, it has higher flexibility than before, especially excellent crack resistance against excessive seam folding, and It has become possible to achieve excellent heat resistance with a good balance.

In addition, the laminated structure of this invention has a resin layer (A) and a resin layer (B) in that order on a flexible printed wiring board on which a copper circuit is formed on a flexible substrate, and the resin layer (B) on the upper layer side is irradiated with light. It is made of a photosensitive thermosetting resin composition that can be patterned, and even if the resin layer (A) on the lower layer side does not contain a photopolymerization initiator, the resin layer (B) and the resin layer (A) can form a pattern all at once by development. It will be dissolved.

The reason is that, when the resin layer (A) on the printed wiring board side does not contain a photopolymerization initiator, this resin layer (A) generally cannot be patterned as a single layer, but in the laminated structure of the present invention, when exposed to light, This is because active species such as radicals generated from the photopolymerization initiator contained in the upper resin layer (B) diffuse into the resin layer (A) immediately below, thereby making it possible to pattern both layers simultaneously.

[Resin layer (A)]

(Alkali-developable resin composition)

The alkali-developable resin composition constituting the resin layer (A) may be a composition containing an alkali-soluble resin that contains at least one functional group selected from the group consisting of a phenolic hydroxyl group and a carboxyl group and can be developed with an alkaline solution, and a heat-reactive compound. Preferred examples include a compound having a phenolic hydroxyl group, a compound having a carboxyl group, and a resin composition containing a compound having a phenolic hydroxyl group and a carboxyl group, and known and commonly used ones are used.

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

Here, as the carboxyl group-containing resin or carboxyl group-containing photosensitive resin, and the compound having an ethylenically unsaturated bond, known and commonly used compounds are used,

In addition, as the heat-reactive compound, a known and commonly used compound having a functional group capable of curing reaction by heat, such as a cyclic (thio)ether group similar to the heat-reactive compound used in the resin layer (B), is used.

This resin layer (A) may or may not contain a photopolymerization initiator, but examples of the photopolymerization initiator used in the case where it contains a photopolymerization initiator include the same photopolymerization initiator as the photopolymerization initiator used in the resin layer (B).

In addition, in the present invention, it is necessary to contain a block copolymer in the resin layer (B), but the effect of the present invention, that is, the required performance of both the solder resist and the cover layer, is not affected even in the resin layer (A). The block copolymer may be contained to this extent. As the block copolymer in this case, the same block copolymer as the block copolymer used in the resin layer (B) can be used. The compounding amount of the block copolymer in the resin layer (A) is preferably 15 parts by mass or less, more preferably 3 parts by mass or less, with respect to 100 parts by mass of the alkali-soluble resin, and especially preferably, the resin layer ( The block copolymer is not contained in A), but contained only in the resin layer (B). If the compounding amount of the block copolymer is 15 parts by mass or less, 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 heat-reactive compound, and a block copolymer.

(Alkali-soluble resin)

As the alkali-soluble resin, the same known and commonly used resin as that of the resin layer (A) can be used, but a carboxyl group-containing resin having at least one of an imide structure and an amide structure, which has better characteristics such as bending resistance and heat resistance, is suitably used. You can use it.

The carboxyl group-containing resin having at least one of the imide structure and the amide structure includes (1) a carboxyl group-containing resin having an imide structure and an amide structure, and (2) a carboxyl group-containing resin having an imide structure and no amide structure. and (3) carboxyl group-containing resins that have an amide structure and do not have an imide structure. These resins can be used individually or in a mixture of two or more types. In the present invention, among carboxyl group-containing resins having at least one of an imide structure and an amide structure, it is preferable to use a carboxyl group-containing resin having an imide structure and an amide structure.

In addition, the carboxyl group-containing resin having at least one of an imide structure and an amide structure may further have a phenolic hydroxyl group.

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

The carboxyl group-containing resin having an imide structure and an amide structure is preferably a polyamidoimide resin, for example, a diamine containing at least a carboxyl group-containing diamine, and an acid having at least three carboxyl groups, two of which are anhydrized. It can be obtained by reacting an acid anhydride (a1) containing an anhydride to obtain an imidide, and then reacting the obtained imidate with a reaction raw material containing a diisocyanate compound. As will be described later, the reaction raw material preferably contains, in addition to the imidide and diisocyanate compounds, an acid anhydride (a2) having at least three carboxyl groups, two of which are anhydrized.

Here, the diamine used in the synthesis of the polyamidoimide resin includes at least a carboxyl group-containing diamine, but it is preferable to use a diamine having an ether bond 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, and 3,5-bis(3-aminophenoxy). Aminophenoxybenzoic acids such as benzoic acid, 3,5-bis(4-aminophenoxy)benzoic acid, 3,3'-methylenebis(6-aminobenzoic acid), 3,3'-diamino-4,4'- Carboxybiphenyl compounds such as dicarboxybiphenyl, 3,3'-diamino-4,4'-dicarboxydiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, etc. carboxydiphenyl alkanes and carboxydiphenyl ether compounds such as 3,3'-diamino-4,4'-dicarboxydiphenyl ether, and these can be used alone or in appropriate combination.

Moreover, examples of diamines having an ether bond include polyoxyethylene diamine, polyoxypropylene diamine, and polyoxyalkylene diamines containing oxyalkylene groups with different carbon chain numbers.

The molecular weight of the diamine having an ether bond is preferably 200 to 3,000, and more preferably 400 to 2,000.

Examples of polyoxyalkylenediamines include polyoxyethylenediamines such as Jeffamine ED-600, ED-900, ED-2003, EDR-148, and HK-511 manufactured by Huntsman, USA, and Jeffamine D-230 and D- Examples include polyoxypropylene diamine such as 400, D-2000, and D-4000, and those having a polytetramethylene ethylene group such as Jeffamine XTJ-542, XTJ533, and XTJ536. Additionally, as the diamine having an ether bond, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane may be used.

As these diamines, diamines other than those may be used in combination. As other diamines that can be used in combination, general-purpose aliphatic diamines, aromatic diamines, etc. can be used individually or in appropriate combination. Specifically, other diamines include, for example, p-phenylenediamine (PPD), 1,3-diaminobenzene, 2,4-toluenediamine, diamine with one benzene nucleus, and 4,4'-diaminodiphenyl ether. , diaminodiphenyl ethers such as 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4 ,4'-diaminobiphenyl, 2,2'-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, 3,3'-bis(3-amino Phenoxy)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-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, 3 Aromatic diamines such as ,3'-diamino-4,4'-dihydroxydiphenylsulfone, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5 -Aliphatic diamines such as diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, and 1,8-diaminoctane can be mentioned.

The acid anhydride (a1) used in the synthesis of the polyamideimide resin includes an acid anhydride having at least three carboxyl groups, two of which are anhydrized. Examples of such acid anhydrides include those having at least one of an aromatic ring and an aliphatic ring, and those having an aromatic ring include trimellitic anhydride (trimellitic anhydride) (benzene-1,2,4-tricarboxylic acid 1). , 2-anhydride, TMA), 4,4'-oxydiphthalic anhydride, hydrogenated trimellitic anhydride (cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride) having an aliphatic ring, etc. , H-TMA), etc. may be suitably mentioned. These acid anhydrides may be used individually by 1 type, or may be used in combination of 2 or more types.

Additionally, carboxylic dianhydride may be used together. Examples of the carboxylic dianhydride include tetracarboxylic acid anhydrides such as pyromellitic dianhydride and 3,3',4,4'-benzophenone tetracarboxylic dianhydride.

Diisocyanate compounds used in the synthesis of the polyamide-imide resin include diisocyanates such as aromatic diisocyanates and their isomers and multimers, aliphatic diisocyanates, alicyclic diisocyanates and isomers thereof, and other general-purpose diisocyanates. can be used, but is not limited to these. In addition, these diisocyanate compounds may be used individually or in combination.

As described above, polyamidoimide resin can be obtained by reacting an imidate with a reaction raw material containing a diisocyanate compound, but the same acid anhydride (a2) as that used to obtain the imidate may be added. do. As this acid anhydride (a2), the same thing as the acid anhydride (a1) mentioned above may be used, or a different thing may be used. The content of acid anhydride (a2) in the reaction raw material in this case is not particularly limited.

As for the polyamideimide resin described above, in particular, the use of diamine containing a carboxyl group, diamine having an ether bond, and H-TMA, an alicyclic trimellitic acid, improves alkali solubility and improves developability. desirable. For the same reason, it is also preferable to use an aliphatic diisocyanate compound for the polyamidoimide resin in the second step reaction. Thereby, by effectively introducing a fatty chain or alicyclic structure into the structure, it becomes possible to increase alkali solubility without significantly reducing the properties.

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

Here, X ₁ is the residue of aliphatic diamine (a) derived from dimer acid having 24 to 48 carbon atoms. X ₂ is the residue of aromatic diamine (b) having a carboxyl group. Y is each independently a cyclohexane ring or an aromatic ring.

Specifically, polyamidoimide resins having this structure include those represented by the following general formula (3).

In the general formula (3), n is a natural number.

(2) Carboxyl group-containing resin with an imide structure and no amide structure

The carboxyl group-containing resin that has an imide structure and does not have an amide structure is not particularly limited as long as it is a resin that has a carboxyl group and an imide ring. For the synthesis of a carboxyl group-containing resin that has an imide structure and no amide structure, a known and common method of introducing an imide ring into the carboxyl group-containing resin can be used. For example, a resin obtained by reacting a carboxylic acid anhydride component with an amine component and/or an isocyanate component can be mentioned. Imidization may be performed by thermal imidation or chemical imidation, and it can be produced by using these in combination.

Here, examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydride and tricarboxylic acid anhydride, but are not limited to these acid anhydrides. Any compound having an acid anhydride group and a carboxyl group that reacts with an amino group or an isocyanate group may be used. , including its derivatives, can be used. Additionally, these carboxylic acid anhydride components may be used individually or in combination.

Examples of tetracarboxylic acid anhydride include pyromellitic dianhydride, 3-fluoropyromellitic dianhydride, 3,6-difluoropyromellitic dianhydride, and 3,6-bis(trifluoromethyl). Pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxalate Cydiphthalic dianhydride, 2,2'-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, 2,2',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) Romethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',5,5'-tetrakis(trifluoromethyl)-3,3',4,4 '-Biphenyltetracarboxylic acid dianhydride, 2,2',6,6'-Tetrakis(trifluoromethyl)-3,3',4,4'-Biphenyltetracarboxylic acid 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'"-quarterphenyltetracarboxylic dianhydride, 3,3"",4,4""-quincphenyl Tetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethynylidene-4,4'-diphthalic dianhydride, 2,2-propylidene-4,4'-di Phthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-di Phthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoro Propropane dianhydride, difluoromethylene-4,4'-diphthalic 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-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-dicarboxy) Phenoxy)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 C) Dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxyl Acid 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 acid dianhydride, 1,2,3,4-butanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3, 3',4,4'-bicyclohexyltetracarboxylic acid 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-ethy Nylidene-4,4'-bis(cyclohexane-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'-difluoroxy-4,4'-diphthalic dianhydride, 5,5'-difluoro Oxy-4,4'-diphthalic dianhydride, 6,6'-difluorooxy-4,4'-diphthalic dianhydride, 3,3',5,5',6,6'-hexafluoro Oxy-4,4'-diphthalic dianhydride, 3,3'-bis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 5,5'-bis(trifluoromethyl)oxy- 4,4'-diphthalic dianhydride, 6,6'-bis(trifluoromethyl)oxy-4,4'-diphthalic dianhydride, 3,3',5,5'-tetrakis(trifluoromethyl) Methyl)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'-difluorosulfonyl-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 acid Dianhydride, 3,3'-bis(trifluoromethyl)sulfonyl-4,4'-diphthalic acid Dianhydride, 5,5'-bis(trifluoromethyl)sulfonyl-4,4'-diphthalic acid Dianhydride, 6,6'-bis(trifluoromethyl)sulfonyl-4,4'-diphthalic dianhydride, 3,3',5,5'-tetrakis(trifluoromethyl)sulfonyl-4 ,4'-diphthalic dianhydride, 3,3',6,6'-tetrakis(trifluoromethyl)sulfonyl-4,4'-diphthalic 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-purple Fluoropropylidene-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'-diphthalic dianhydride, 5,5'-bis(trifluoromethyl)-2,2-perfluoropropylidene-4,4'-diphthalic dianhydride, 6 ,6'-difluoro-2,2-perfluoropropylidene-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'-diphthalic dianhydride, 9-phenyl-9-(trifluoromethyl ) xanthene-2,3,6,7-tetracarboxylic dianhydride, 9,9-bis (trifluoromethyl) [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 bistrimellitate dianhydride, 1,2-(ethylene)bis(trimellitate anhydride), 1, 3-(trimethylene)bis(trimellitate anhydride), 1,4-(tetramethylene)bis(trimellitate anhydride), 1,5-(pentamethylene)bis(trimellitate anhydride), 1,6- (Hexamethylene)bis(trimellitate anhydride), 1,7-(heptamethylene)bis(trimellitate anhydride), 1,8-(octamethylene)bis(trimellitate anhydride), 1,9-(nona Methylene)bis(trimellitate anhydride), 1,10-(decamethylene)bis(trimellitate anhydride), 1,12-(dodecamethylene)bis(trimellitate anhydride), 1,16-(hexadeca Methylene)bis(trimellitate anhydride), 1,18-(octadecamethylene)bis(trimellitate anhydride), etc. can be mentioned. Examples of tricarboxylic acid anhydride include trimellitic acid anhydride and nuclear hydrogenated trimellitic acid anhydride.

As the amine component, diamines such as aliphatic diamine and aromatic diamine, polyhydric amines such as aliphatic polyetheramine, diamines having a carboxylic acid, diamines having a phenolic hydroxyl group, etc. can be used, but are not limited to these amines. Additionally, these amine components may be used individually or in combination.

Examples of the diamine include diamines with one benzene nucleus, such as p-phenylenediamine (PPD), 1,3-diaminobenzene, 2,4-toluenediamine, 2,5-toluenediamine, and 2,6-toluenediamine. , diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, etc. Phenylmethane, 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'-diaminodiphenyl Methane, bis(4-aminophenyl)sulfide, 4,4'-diaminobenzanilide, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (o-tolidine), 2,2'-dimethyl Benzidine (m-tolidine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4, 4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'- Diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 3,3'-diamino-4,4' -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 Seed, two benzene nuclei such as 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, etc. Diamine, 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(3-aminophenyl)benzene, 1,4-bis(4-amino) Phenyl)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-amino) Phenyl sulfide) benzene, 1,3-bis (3-aminophenyl sulfone) benzene, 1,3-bis (4-aminophenyl sulfone) benzene, 1,4-bis (4-aminophenyl sulfone) 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, 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-(4-aminophenoxy) Si) 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, 2,2-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) Si) phenyl] propane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [3-( 4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1, Benzene nucleus 4, such as 3,3,3-hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, etc. Aromatic diamines such as diamine, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7 -diaminoheptane, 1,8-diaminoctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1, Aliphatic diamines such as 2-diaminocyclohexane can be used, and examples of aliphatic polyetheramines include ethylene glycol and/or propylene glycol-based polyhydric amines.

As amines having a carboxyl group, diaminobenzoic acids such as 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, and 3,4-diaminobenzoic acid, 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 Carboxylic acids such as '-dicarboxybiphenyl, 4,4'-diamino-2,2'-dicarboxybiphenyl, 4,4'-diamino-2,2',5,5'-tetracarboxybiphenyl, etc. Biphenyl compounds, 3,3'-diamino-4,4'-dicarboxydiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 2,2-bis[3 -Amino-4-carboxyphenyl]propane, 2,2-bis[4-amino-3-carboxyphenyl]propane, 2,2-bis[3-amino-4-carboxyphenyl]hexafluoropropane, 4,4 Carboxydiphenylalkanes such as carboxydiphenylmethane such as '-diamino-2,2',5,5'-tetracarboxydiphenylmethane, 3,3'-diamino-4,4'-dicarboxydi Phenyl ether, 4,4'-diamino-3,3'-dicarboxydiphenyl ether, 4,4'-diamino-2,2'-dicarboxydiphenyl ether, 4,4'-diamino-2 Carboxydiphenyl ether compounds such as ,2',5,5'-tetracarboxydiphenyl ether, 3,3'-diamino-4,4'-dicarboxydiphenyl sulfone, 4,4'-diamino-3 ,3'-dicarboxydiphenylsulfone, 4,4'-diamino-2,2'-dicarboxydiphenylsulfone, 4,4'-diamino-2,2',5,5'-tetracarboxydi Diphenylsulfone compounds such as phenylsulfone, bis[(carboxyphenyl)phenyl]alkane compounds such as 2,2-bis[4-(4-amino-3-carboxyphenoxy)phenyl]propane, 2,2-bis and bis[(carboxyphenoxy)phenyl]sulfone compounds such as [4-(4-amino-3-carboxyphenoxy)phenyl]sulfone.

As the isocyanate component, diisocyanates such as aromatic diisocyanates and their isomers and multimers, aliphatic diisocyanates, alicyclic diisocyanates and their isomers, and other general-purpose diisocyanates can be used, but are not limited to these isocyanates. . In addition, these isocyanate components may be used individually 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, and diphenyl ether diisocyanate. Diisocyanate and its isomers, polymers, aliphatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate, or alicyclic diisocyanates and isomers obtained by hydrogenating the above aromatic diisocyanates, or Other general-purpose diisocyanates can be mentioned.

(3) Carboxyl group-containing resin with an amide structure and no imide structure

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

In order to cope with the photolithography process, the carboxyl group-containing resin suitably used as the alkali-soluble resin of the present invention as described above preferably has an acid value of 20 to 200 mgKOH/g, and more preferably 60 to 150 mgKOH/g. do. If this acid value is 20 mgKOH/g or more, solubility in alkali increases, developability becomes good, and furthermore, the degree of crosslinking with the heat-curing component after light irradiation increases, so that sufficient development contrast can be obtained. On the other hand, if the acid value is 200 mgKOH/g or less, accurate pattern drawing becomes easy, so-called thermal blurring can be suppressed, especially in the PEB (POST EXPOSURE BAKE) process after light irradiation, which will be described later, and the process margin increases.

In addition, considering developability and cured film properties, the molecular weight of this carboxyl group-containing resin is preferably 100,000 or less, more preferably 1,000 to 100,000, and still more preferably 2,000 to 50,000. If this molecular weight is 100,000 or less, the alkali solubility of the unexposed area increases and developability improves. On the other hand, if the molecular weight is 1,000 or more, sufficient development resistance and cured material properties can be obtained in the exposed area after exposure and PEB.

(Photopolymerization initiator)

As the photopolymerization initiator used in the resin layer (B), a known and commonly used photopolymerization initiator can be used, and especially when used in the PEB process after light irradiation described later, a photopolymerization initiator that also functions as a photobase generator is suitable. Additionally, in this PEB process, a photopolymerization initiator and a photobase generator may be used together.

A photopolymerization initiator that also functions as a photobase generator is a type that can function as a catalyst for the polymerization reaction of a heat-reactive compound, which will be described later, by changing the molecular structure or cleavage of the molecule by irradiation of light such as ultraviolet rays or visible light. It is a compound that produces the above basic substances. Examples of basic substances include secondary amines and tertiary amines.

Photopolymerization initiators that also function as such photobase generators include, for example, α-aminoacetophenone compounds, oxime ester compounds, acyloxyimino groups, N-formylated aromatic amino groups, N-acylated aromatic amino groups, and nitrobenzylcarboxyl groups. Compounds having substituents such as a bamate group and an alkoxybenzyl carbamate group can be mentioned. Among these, oxime ester compounds and α-aminoacetophenone compounds are preferable, and oxime ester compounds are more preferable. As the α-aminoacetophenone compound, those having two or more nitrogen atoms are particularly preferable.

The α-aminoacetophenone compound may have a benzoin ether bond in the molecule, and when irradiated with light, cleavage occurs within the molecule to generate a basic substance (amine) that acts as a curing catalyst.

As the oxime ester compound, any compound can be used as long as it produces a basic substance when irradiated with light.

These photopolymerization initiators may be used individually by one type, or may be used in combination of two or more types. The amount of the photopolymerization initiator in 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. In the case of 0.1 mass part or more, good development resistance contrast of the light irradiated part/unirradiated part can be obtained. Additionally, in the case of 40 parts by mass or less, the properties of the cured product improve.

(thermal reactive compound)

As the heat-reactive compound, a known and commonly used compound having a functional group capable of curing reaction by heat such as a cyclic (thio)ether group, such as an epoxy compound, is used.

Examples of the epoxy compounds include bisphenol A-type epoxy resin, brominated epoxy resin, novolak-type epoxy resin, bisphenol F-type epoxy resin, hydrogenated bisphenol A-type epoxy resin, glycidylamine-type epoxy resin, hydantoin-type epoxy resin, and alicyclic epoxy resin. formula epoxy resin, trihydroxyphenylmethane type epoxy resin, bixylenol type or biphenol type epoxy resin, or mixtures thereof; Bisphenol S-type epoxy resin, bisphenol A novolac-type epoxy resin, tetraphenylolethane-type epoxy resin, heterocyclic epoxy resin, diglycidyl phthalate resin, tetraglycidylxylenoylethane resin, naphthalene group-containing epoxy resin, DC Examples include epoxy resins having a chlorpentadiene skeleton, glycidyl methacrylate copolymer epoxy resins, cyclohexyl maleimide and glycidyl methacrylate copolymer epoxy resins, and CTBN-modified epoxy resins.

As the compounding amount of the heat-reactive compound, the equivalent ratio (alkali-soluble group such as carboxyl group: heat-reactive group such as epoxy group) with the alkali-soluble resin is preferably 1:0.1 to 1:10. By setting the mixing ratio within this range, development becomes good and fine patterns can be easily formed. It is more preferable that the equivalence ratio is 1:0.2 to 1:5.

(block copolymer)

The block copolymer is the most characteristic feature of the resin layer (B) constituting the laminated structure of the present invention in order to achieve higher flexibility than ever before, especially excellent crack resistance against excessive seam folding, and excellent heat resistance in a good balance. It is an enemy ingredient.

This block copolymer generally refers to a copolymer with a molecular structure in which two or more types of polymer units with different properties are linked by covalent bonds to form a long chain. In the present invention, known and commonly used block copolymers can be used, and X-Y type or X-Y-X type block copolymers are preferable, and X-Y-X type block copolymers are more preferable. X in the X-Y-X type block copolymer may be the same or different.

Furthermore, among the X-Y type or X-Y-X type block copolymers, it is preferable that X is a polymer unit having a glass transition point Tg of 0°C or higher. More preferably, X is a polymer unit having a glass transition point Tg of 50°C or higher. Moreover, Y is preferably a polymer unit with a glass transition point Tg of less than 0°C, and more preferably a polymer unit with a glass transition point Tg of -20°C or less. The glass transition point Tg is measured by differential scanning calorimetry (DSC).

It is more preferable that the block copolymer is solid at 20 to 30°C. In this case, it may be solid within this range, and may also be solid at temperatures outside this range. By being solid in the above temperature range, it has excellent tackiness when formed into a dry film or applied to a substrate and temporarily dried.

Moreover, among the X-Y-X type block copolymers, it is preferable that X has high compatibility with heat-reactive compounds, and that Y has low compatibility with heat-reactive compounds. In this way, by making a block copolymer in which the blocks at both ends are compatible with the matrix and the block in the center is incompatible with the matrix, it is thought that it becomes easier to exhibit a specific structure in the matrix.

Polymethyl methacrylate (PMMA), polystyrene (PS), etc. are preferred as the polymer unit . In addition, if a hydrophilic unit with excellent compatibility with alkali-soluble resins, such as styrene units, hydroxyl group-containing units, carboxyl group-containing units, epoxy group-containing units, and N-substituted acrylamide units, is introduced into part of the polymer unit Further improvements are possible. It is particularly preferred to introduce epoxy group-containing units into some of the polymer units X. Among the above, it is preferable that the polymer unit Additionally, Y is preferably poly n-butyl (meth)acrylate or polybutadiene. X and Y may each be composed of one type of polymer unit, or may be composed of polymer units made of two or more types of components.

Examples of the method for producing block copolymers include methods described in Japanese Patent Publication No. 2005-515281 and Japanese Patent Publication No. 2007-516326.

Commercially available X-Y-X type block copolymers include acrylic triblock copolymers manufactured using living polymerization manufactured by Arcmas. Specific examples thereof include X-Y- Examples include X-Y-X type block copolymers (e.g., SM4032XM10, etc.) and hydrophilic group-modified X-Y-

Additionally, the mass average molecular weight (Mw) of the block copolymer is usually 20,000 to 400,000, and is preferably in the range of 30,000 to 300,000. It is preferable that the molecular weight distribution (Mw/Mn) is 3 or less.

When the mass average molecular weight is 20,000 or more, the composition has mechanical properties such as flexibility and elasticity, while the adhesion does not become excessively high, the effect of improving flexibility and crack resistance becomes good, and the adhesion also becomes good. On the other hand, if the mass average molecular weight is 400,000 or less, the viscosity of the composition does not become too high and printability and developability are unlikely to decrease.

Block copolymers may be used individually or in combination of two or more types. The compounding 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, based on 100 parts by mass of the alkali-soluble resin. When the compounding amount of the block copolymer is 1 part by mass or more, flexibility and heat resistance improve, and when it is 60 parts by mass or less, the balance of flexibility and heat resistance becomes good.

The following components can be blended as needed in the resin composition used in the resin layer (A) and resin layer (B) as described above.

(polymer resin)

For the purpose of improving the flexibility and touch drying properties of the resulting cured product, known and commonly used polymer resins can be blended, excluding the block copolymers mentioned above. Examples of such polymer resins include cellulose-based, polyester-based, phenoxy resin-based polymers, polyvinyl acetal-based, polyvinyl butyral-based, polyamide-based, and polyamidoimide-based binder polymers and elastomers. One type of this polymer resin may be used individually, or two or more types may be used together.

(Inorganic filler)

Inorganic fillers can be mixed 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, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, boron nitride, Neuburg diatomaceous earth, etc. You can.

(coloring agent)

As the colorant, known and commonly used colorants such as red, blue, green, yellow, white, and black can be blended, and any of pigments, dyes, and pigments may be used.

(organic solvent)

Organic solvents can be blended to prepare a resin composition or to adjust viscosity for application to a substrate or carrier film. Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum solvents. These organic solvents may be used individually or as a mixture of two or more types.

(Other Ingredients)

If necessary, additional components such as mercapto compounds, adhesion promoters, antioxidants, and ultraviolet absorbers can be added. These can be used as known and common ones. In addition, well-known thickeners such as fine powdered silica, hydrotalcite, organic bentonite, and montmorillonite, and well-known additives such as silicone-based, fluorine-based, polymer-based antifoaming agents and/or leveling agents, silane coupling agents, and rust inhibitors can be mixed. You can.

Since the laminated structure of the present invention has excellent flexibility, it can be used in at least one of the bent portion and the non-bent portion of a flexible printed wiring board, and is also used for at least one of the coverlay, solder resist, and interlayer insulating material of the flexible printed wiring board. It can be used as.

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

(dry film)

The dry film of the present invention can be manufactured, for example, as follows. That is, first, on a carrier film (support film), the composition constituting the resin layer (B) and the composition constituting the resin layer (A) are respectively diluted with an organic solvent to adjust the viscosity to an appropriate viscosity, and the composition constituting the resin layer (B) is adjusted to an appropriate viscosity according to a conventional method. Apply sequentially using a known method such as a coater. Thereafter, a dry film consisting of the resin layer (B) and the resin layer (A) can be formed on the carrier film by drying at a temperature of usually 50 to 130°C for 1 to 30 minutes. On this dry film, a peelable cover film (protective film) can 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 appropriately used, and the cover film is preferably smaller than the adhesive force between the resin layer and the carrier film when peeling off the cover film. There is no particular limitation on the thickness of the carrier film and cover film, but is generally appropriately selected in the range of 10 to 150 μm.

(Flexible printed wiring board)

The flexible printed wiring board of the present invention has an insulating film formed by forming a layer of the laminated structure of the present invention on a flexible printed wiring substrate, patterning it by light irradiation, and forming the pattern all at once with a developer.

(Manufacturing method of wiring board)

Manufacturing of a flexible printed wiring board using the laminated structure of the present invention can be performed according to the procedure shown in the process diagram in FIG. 1. That is, a step of forming a layer of the laminated structure of the present invention on a flexible wiring substrate on which a conductor circuit is formed (lamination step), a step of irradiating active energy rays in a pattern to the layer of this laminated structure (exposure step), and This is a manufacturing method that includes a step of alkali developing the layers of the laminated structure to collectively form the layers of the patterned laminated structure (development step). In addition, if necessary, after alkali development, further photocuring or thermal curing (post-curing process) is performed to completely cure the layers of the laminated structure, and a highly reliable flexible printed wiring board can be obtained.

Additionally, manufacturing of a flexible printed wiring board using the laminated structure of the present invention can also be performed according to the procedure shown in the process diagram of FIG. 2. That is, a process of forming a layer of the laminated structure of the present invention on a flexible wiring substrate on which a conductor circuit is formed (lamination process), a process of irradiating active energy rays in a pattern to the layer of this laminated structure (exposure process), It is a manufacturing method that includes a process of heating a layer of a laminated structure (heating (PEB) process) and a process of alkali developing a layer of a laminated structure to form a patterned layer of a laminated structure (development process). In addition, if necessary, after alkali development, further photocuring or thermal curing (post-curing process) is performed to completely cure the layers of the laminated structure, and a highly reliable flexible printed wiring board can be obtained. In particular, in the resin layer (B), when a carboxyl group-containing resin having at least one of an imide structure and an amide structure is used, it is preferable to use the procedure shown in the process diagram of FIG. 2.

Hereinafter, each process shown in FIG. 1 or FIG. 2 will be described in detail.

[Laminate process]

In this process, a resin layer 3 (resin layer (A)) made of an alkali-developable resin composition containing an alkali-soluble resin, etc. is applied to the flexible printed wiring substrate 1 on which the conductor circuit 2 is formed, and a resin layer. (3) A laminated structure consisting of the upper resin layer 4 (resin layer (B)) made of a photosensitive thermosetting resin composition containing an alkali-soluble resin, etc. is formed. Here, each resin layer constituting the laminated structure is formed, for example, by sequentially applying and drying the resin composition constituting the resin layers 3 and 4 to the wiring substrate 1 and drying it. Alternatively, the resin composition constituting the resin layers 3 and 4 may be formed in the form of a dry film with a two-layer structure by laminating it to the wiring substrate 1.

The method for applying the resin composition to the wiring substrate may be any known method such as a blade coater, lip coater, comma coater, or film coater. In addition, the drying method uses a heat source of a steam heating type such as a hot air circulation drying furnace, an IR furnace, a hot plate, or a convection oven, a method of countercurrent contact with hot air in the dryer, and a method of spraying the support from a nozzle. Any known method, such as a method of doing so, will suffice.

As a method of laminating the resin composition to the wiring substrate, it is preferable to join under pressure and heating using a vacuum laminator or the like. By using such a vacuum laminator, even if the surface of the wiring substrate has irregularities, the dry film is in close contact with the wiring substrate, so air bubbles are not mixed, and the hole filling property of the concave portion of the wiring substrate surface is also improved. Pressurizing conditions are preferably about 0.1 to 2.0 MPa, and heating conditions are preferably 40 to 120°C.

[Exposure process]

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

As an exposure machine used in this process, a direct drawing device, an exposure machine equipped with a metal halide lamp, etc. can be used. The mask for exposure on the pattern is a negative type mask.

As the active energy ray used for exposure, it is preferable to use laser light or scattered light with a maximum wavelength in the range of 350 to 450 nm. By setting the maximum wavelength within this range, the photopolymerization initiator can be activated efficiently. In addition, the exposure amount varies depending on the film thickness, etc., but can usually be 100 to 1500 mJ/cm ² .

[PEB process]

In this process, the exposed portion is cured by heating the resin layer after exposure. By this process, a photopolymerization initiator having a function as a photobase generator is used, or the base generated in the exposure step of the resin layer (B) consisting of a composition using a photopolymerization initiator and a photobase generator in combination is used to form the resin layer (B). ) can be hardened to the core. The heating temperature is, for example, 80 to 140°C. The heating time is, for example, 10 to 100 minutes. Since curing of the resin composition in the present invention is, for example, a ring-opening reaction of an epoxy resin by a thermal reaction, deformation and curing shrinkage can be suppressed compared to the case where curing proceeds through a photo radical reaction.

[Development process]

In this process, the unexposed portion is removed by alkaline development to form a negative patterned insulating film, particularly a coverlay and solder resist. The development method may be a known method such as dipping. Additionally, as a developing solution, sodium carbonate, potassium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, alkaline aqueous solutions such as tetramethylammonium hydroxide aqueous solution (TMAH), or a mixture thereof can be used.

[Post-cure process]

In this process, after the development process, the insulating film is completely heat-cured to obtain a highly reliable coating film. The heating temperature is, for example, 120°C to 180°C. The heating time is, for example, 5 minutes to 120 minutes. In addition, the insulating film may be additionally irradiated with light before or after post-curing.

Example

Hereinafter, the present invention will be described in more detail through Examples and Comparative Examples, but the present invention is not limited by these Examples and Comparative Examples.

<Synthesis Example 1: Synthesis example of polyimide resin solution>

In a separable three-necked flask equipped with a stirrer, nitrogen introduction tube, dividing ring, and cooling ring, 22.4 g of 3,3'-diamino-4,4'-dihydroxydiphenylsulfone, 2,2'-bis[ Add 8.2g of 4-(4-aminophenoxy)phenyl]propane, 30g of NMP, 30g of γ-butyrolactone, 27.9g of 4,4'-oxydiphthalic anhydride, and 3.8g of trimellitic anhydride. , and stirred for 4 hours at 100 rpm at room temperature under a nitrogen atmosphere. Next, 20 g of toluene was added, and the mixture was stirred for 4 hours at a silicone bath temperature of 180°C and 150 rpm while distilling off toluene and water 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 18 mgKOH, Mw was 10,000, and the hydroxyl equivalent was 390.

(Examples 1 to 6 and Comparative Examples 1 to 4)

According to the component compositions shown in Table 1 and Table 2, the materials shown in Examples 1 to 6 and Comparative Examples 1 to 4 were mixed, premixed in a stirrer, and then kneaded in a three-roll mill to form each resin layer. A resin composition for the following was prepared. The values in the table are parts by mass of solid content, unless otherwise specified.

<Formation of resin layer (A)>

A flexible printed wiring substrate on which a circuit with a copper thickness of 18 µm was formed was prepared, and pretreatment was performed using Mack CZ-8100. Thereafter, the resin composition constituting each resin layer (A) obtained in Examples 1 to 6 and Comparative Examples 1 to 4 was applied to the pretreated flexible printed wiring substrate so that the film thickness after drying was 25 μm. After that, it was dried in a hot air circulation type drying furnace at 90°C/30 minutes to form a resin layer (A).

<Formation of resin layer (B)>

On the resin layer (A) formed above, the resin compositions constituting each resin layer (B) obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were applied so that the film thickness after drying was 10 μm. After that, it was dried in a hot air circulation type drying furnace at 90°C/30 minutes to form a resin layer (B).

In this way, an uncured laminated structure consisting of the resin layer (A) and the resin layer (B) described in Examples 1 to 6 and Comparative Examples 1 to 4 was formed on the flexible printed wiring substrate.

<Flexibility>

(Production of test pieces)

The uncured laminated structure on each flexible printed wiring substrate formed as described above was first exposed to 500 mJ/cm through a negative mask using an exposure device equipped with a metal halide lamp (HMW-680-GW20). The entire surface was exposed as ² . Afterwards, a PEB process was performed at 90°C for 30 minutes, development (30°C, 0.2 MPa, 1 mass% Na ₂ CO ₃ aqueous solution) was performed for 60 seconds, and heat curing was performed at 150°C for 60 minutes to form a cured laminated structure. A flexible printed wiring board was manufactured.

Then, this flexible printed wiring board was cut to about 15 mm x about 110 mm to produce a test piece.

(MIT exam)

For each obtained test piece, an MIT test was performed using an MIT fold fatigue tester type D (manufactured by Toyo Seiki Seisakusho) in accordance with JIS P8115, and the flexibility was evaluated. Specifically, as shown in FIG. 3, the test piece 10 is mounted on the device, and with a load F (0.5 kgf) applied, the test piece 10 is installed vertically in the clamp 11 and bent. Bending was performed at an angle α of 135 degrees and a speed of 175 cpm, and the number of reciprocating bends until fracture was measured. Additionally, the test environment was 25°C.

The evaluation criteria are as follows.

◎: It was bent more than 200 times, and no cracks occurred in the cured coating film at the bending point.

○: It was bent 170 to 199 times, and no cracks were formed equally.

△: It was bent 150 to 169 times, and no cracks occurred equally.

×: Cracks occurred when the number of bending was 149 or less.

(Seam folding test)

Additionally, for each obtained test piece, the flexibility was evaluated when a seam folding test was performed under the excessive conditions shown below. Specifically, as shown in FIG. 4, the test piece 10 is bent at 180° so that the conductor circuit and the formed surface After seam folding by applying a clamping load G (standard weight of 1 kg) for 10 seconds, use an optical microscope to check whether cracks have occurred in the cured coating portion 20 at the bent point for one cycle, and check whether cracks have occurred. The number of occurrences was recorded. The test environment was 25°C.

The evaluation criteria are as follows.

◎: It was bent more than 10 times, and no cracks occurred in the cured coating film at the bending point.

○: It was bent 6 to 9 times and no cracks occurred equally.

△: It was bent 3 to 5 times, and no cracks occurred equally.

×: Cracks occurred when the number of bending was 2 or less.

These evaluation results are shown together in Table 1 and Table 2.

<Heat resistance>

With respect to the uncured laminated structure on each flexible printed wiring substrate, in which the laminated structure was formed as described above, first, using an exposure apparatus equipped with a metal halide lamp (HMW-680-GW20), a layer with a diameter of about 2 mm to about 2 mm was formed on copper. It was exposed to light at 500 mJ/cm ² through a negative mask with an opening of 5 mm. Afterwards, a PEB process was performed at 90°C for 30 minutes, development (30°C, 0.2 MPa, 1 mass% Na ₂ CO ₃ aqueous solution) was performed for 60 seconds, and heat curing was performed at 150°C for 60 minutes to form a cured laminated structure. A flexible printed wiring board (test board) was produced.

Rosin-based flux was applied to this test board and immersed in a soldering tank previously set at 260°C and 280°C for 10 seconds to evaluate the occurrence of lifting, swelling, and peeling of the cured coating film.

The evaluation criteria are as follows.

◎: No lifting, swelling, or peeling occurred during immersion at either 260°C or 280°C.

○: When immersed at 260°C, no lifting, swelling, or peeling occurred, but when immersed at 280°C, lifting, swelling, or peeling occurred.

×: Floating and peeling occurred in both immersion at 260°C and 280°C.

The evaluation results are shown together in Table 1 and Table 2.

<Resolution>

With respect to the uncured laminated structure on each flexible printed wiring substrate, where the laminated structure was formed as described above, an exposure apparatus equipped with a metal halide lamp (HMW-680-GW20) was first used, and 500 mJ/cm was applied through a negative mask. ² , the pattern was exposed to form an opening with a diameter of 200㎛. Afterwards, a PEB process is performed at 90°C for 30 minutes, development (30°C, 0.2 MPa, 1% by mass Na ₂ CO ₃ aqueous solution) is performed for 60 seconds to draw a pattern, and heat curing is performed at 150°C for 60 minutes to form an opening. A flexible printed wiring board formed with a cured laminated structure having was manufactured. The opening formed in the laminated structure of the obtained flexible printed wiring board was observed using an optical microscope adjusted to 100 times, and the resolution was evaluated.

The evaluation criteria are as follows.

○: The opening is fully formed.

×: No opening was formed.

The evaluation results are shown together in Tables 1 and 2.

*1) Alkali-soluble resin 1: ZAR-1035: acid-modified bisphenol A type epoxy acrylate, acid value 98 mgKOH/g (manufactured by Nippon Kayaku Co., Ltd.)

*2) Polyimide resin: PI-1: Synthesis Example 1

*3) Photocurable monomer: BPE-500: Ethoxylated bisphenol A dimethacrylate (manufactured by Shinnakamura Chemical Co., Ltd.)

*4) Epoxy resin: E828: Bisphenol A type epoxy resin, epoxy equivalent weight 190, mass average molecular weight 380 (manufactured by Mitsubishi Chemical Corporation)

*5) Photopolymerization initiator: IRGACURE OXE02: Oxime-based photopolymerization initiator (manufactured by BASF)

*6) Block copolymer 1: M52N: X-Y-X type block copolymer mass average molecular weight (Mw) about 100,000, Arkmas company, NANOSTRENGTH (registered trademark)

*7) Block copolymer 2: M65N: X-Y-X type block copolymer mass average molecular weight (Mw) about 100,000 to 300,000, manufactured by Arcmas, NANOSTRENGTH (registered trademark)

*8) Alkali-soluble resin 2: P7-532: polyurethane acrylate, acid value 47 mgKOH/g (manufactured by Kyoesha Chemical Co., Ltd.)

As is clear from the evaluation results shown in the above table, in the laminated structures of each Example, by containing the block copolymer in the resin layer (B) on the upper layer side, excellent performance was obtained in terms of flexibility, heat resistance, and resolution. You can see that you are losing. On the other hand, in Comparative Examples 1 and 2, which have a single-layer structure, the flexibility, especially excellent crack resistance against excessive seam folding, is insufficient, and in Comparative Example 3, which does not contain a block copolymer even if it is a laminated structure, good results are obtained with respect to heat resistance. was obtained, but the flexibility, especially the good crack resistance to excessive seam folding, became insufficient. In addition, in Comparative Example 4, in which the block copolymer was contained only in the resin layer (A) on the lower layer side of the laminated structure, good results were obtained with respect to heat resistance, but flexibility, especially excellent crack resistance to excessive seam folding, and resolution were insufficient. It's done.

From the above, by containing the block copolymer in the resin layer (B) on the upper layer side among the laminated structures formed by laminating two resin layers, while maintaining the original properties of the photosensitive resin composition such as resolution, flexibility, especially excessive It has become possible to improve excellent crack resistance and heat resistance against seam folding with a good balance.

1 Flexible printed wiring substrate
two conductor circuit
3 resin layer
4 Resin layer
5 mask
10 test piece
11 clamp
12 reputation
20 Hardened coating part
X Conductor circuit and formation surface of cured coating film

Claims (9)

A laminated structure having a resin layer (A) and a resin layer (B) laminated on a flexible printed wiring board through the resin layer (A),
The resin layer (B) is made of a photosensitive thermosetting resin composition containing an alkali-soluble resin, a photopolymerization initiator, a heat-reactive compound, and a block copolymer, and the resin layer (A) is made of an alkali-soluble resin and a heat-reactive compound. It is made of an alkali-developable resin composition containing,
The block copolymer is of type XY or XYX, where The layered structure according to claim 1, wherein the block copolymer is of the X-Y-X type. The layered structure according to claim 1, wherein the block copolymer has a mass average molecular weight (Mw) of 20,000 to 400,000. The laminated structure according to claim 1, which contains a photobase generator as a photopolymerization initiator of the resin layer (B). The laminated structure according to claim 1, wherein the resin layer (A) is made of an alkali-developable resin composition containing no photopolymerization initiator. The laminated structure according to claim 1, used for at least one of a bent portion and a non-bent portion of a flexible printed wiring board. The laminated structure according to claim 1, which is used for at least one of a coverlay, a solder resist, and an interlayer insulating material for a flexible printed wiring board. A dry film, wherein at least one side of the laminated structure according to claim 1 is supported or protected by a film. A flexible printed wiring board comprising an insulating film using the laminated structure according to claim 1.

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