WO2014171525A1 - Laminate structure, flexible printed wiring board and method for manufacturing same - Google Patents

Abstract

Provided are a photosensitive resin structure enabling the forming of a fine pattern on a flexible printed wiring board and having excellent insulation properties and bendability, and a flexible printed wiring board having a cured photosensitive resin structure as a protective film such as a cover lay or a solder resist. In the photosensitive resin structure having a development adhesive layer (a) and a development protective layer (b) laminated on a flexible printed wiring board over the development adhesive layer (a), light irradiation may be used for patterning at least the development protective layer (b) and developing the development adhesive layer (a) and the development protective layer (b) enables the collective formation of a pattern.

Description

Laminated structure, flexible printed wiring board and manufacturing method thereof

The present invention relates to a laminated structure, in particular, a photosensitive resin structure, a dry film using the same, and a flexible printed wiring board, and more particularly, a photosensitive resin structure capable of forming a fine pattern on the flexible printed wiring board. And a flexible printed wiring board having the cured product thereof as a protective film, for example, a coverlay or a solder resist, and a method for manufacturing the same.

Conventionally, a non-photosensitive resin structure obtained by applying a thermosetting adhesive to a film such as polyimide has been used as a protective film for a flexible printed wiring board. As a method for forming such a non-photosensitive resin structure on a flexible printed wiring board by patterning, conventionally, a method of thermocompression bonding on the flexible printed wiring board after punching by punching has been used. Alternatively, a method has been used in which a solvent-soluble thermosetting resin composition is directly pattern-printed on a flexible printed wiring board and thermally cured to form a pattern. In particular, a polyimide film has been used as a suitable material for a flexible printed wiring board because it has flexibility and is excellent in heat resistance, mechanical properties, and electrical properties (see, for example, Patent Document 1).

However, in the conventional method described above, the shape of the pattern edge part collapses due to resin oozing at the time of application or thermocompression bonding, so it is required for miniaturization of wiring and miniaturization of chip parts mounted on flexible printed wiring boards. It was difficult to form a fine pattern.

On the other hand, in recent years, it has become necessary to reduce the circuit board space due to the small size and thinness of electronic devices due to the spread of smartphones and tablet terminals. Therefore, the use of the flexible printed wiring board which can be folded and accommodated is expanded, and the reliability with respect to such a flexible printed wiring board is required to be higher than ever.

On the other hand, as an insulating film to ensure the insulation reliability of flexible printed wiring boards, a cover based on polyimide with excellent mechanical properties such as heat resistance and flexibility is used for the bent part (bent part). Lay is used (see, for example, Patent Documents 2 and 3), and the mounting part (non-bent part) uses a photosensitive resin composition that is excellent in electrical insulation and solder heat resistance and can be finely processed. Is widely adopted.

However, a polyimide-based coverlay with excellent mechanical properties such as heat resistance and flexibility is not suitable for fine wiring because it requires processing by die punching. Therefore, it is necessary to partially use an alkali developing type photosensitive resin composition (solder resist) that can be processed by photolithography in a chip mounting portion that requires fine wiring.

WO2012 / 133665 gazette JP-A-62-263692 Japanese Patent Laid-Open No. 63-110224

As described above, in the manufacturing process of the flexible printed wiring board, there is a problem that it is inferior in cost and workability because it is necessary to adopt a mixed mounting process of a process of attaching a cover lay and a process of forming a solder resist.

For such a mixed loading process, proposals have conventionally been made to apply an insulating film as a solder resist as a coverlay of a flexible printed wiring board. However, the photosensitive solder resist in flexible printed wiring boards requires low crosslink density and addition of an elastomer component in order to impart flexibility, which reduces electrical reliability, impact resistance, flexibility, etc. This is inferior in reliability to the thermosetting protective film. Therefore, the batch forming process of the bent part (bent part) and the mounting part (non-bent part) has not been put to practical use. In addition, since the resin composition for solder resist is accompanied by curing shrinkage due to acrylic photopolymerization, there is a problem in dimensional stability such as warping of a flexible wiring board.

On the other hand, as a photosensitive polyimide capable of achieving both alkali solubility and mechanical properties, a method of using a polyimide precursor and performing thermal ring closure after patterning has been proposed. However, problems remain in the workability of wiring board manufacture, such as requiring high-temperature treatment, and it has not yet been put into practical use.

In addition, it is conceivable to apply an insulating film as a coverlay as a solder resist for a flexible printed wiring board. However, such a coverlay film requires a complicated process for pattern formation, and is not suitable for punching holes by punching. There is a problem that it is difficult to cope with the formation of a fine pattern due to low processing accuracy and oozing of the resin during thermocompression bonding.

Therefore, an object of the present invention is to form a photosensitive resin structure that is capable of forming a fine pattern on a flexible printed wiring board and is excellent in insulation and flexibility, and a cured product thereof as a protective film, for example, a coverlay or a solder resist. It is in providing the flexible printed wiring board which has.

Another object of the present invention is to provide an insulating film for a flexible printed wiring board having excellent reliability and processing accuracy such as impact resistance, bendability, and low warpage, and excellent workability. Part) and a laminated structure suitable for the batch formation process of the mounting part (non-bending part) and its cured product as a protective film, for example, coverlay or solder resist, for reliability such as impact resistance and flexibility The object is to provide an excellent flexible printed wiring board.

Still another object of the present invention is to provide an insulating film for a flexible printed wiring board excellent in reliability and processing accuracy such as impact resistance, bendability, and low warpage, particularly a bent portion (bend portion) and mounting. An object of the present invention is to provide a flexible printed wiring board manufacturing method and a flexible printed wiring board capable of forming an insulating film, such as a cover lay and a solder resist, at a portion (non-bent portion) with good workability.

As a result of diligent investigations to achieve the above object, the present inventors have made the above object by forming a protective film for a flexible printed wiring board from a photosensitive resin structure in which a plurality of developable resin layers are laminated. The present invention has been completed.

That is, the photosensitive resin structure of the present invention comprises a developable adhesive layer (a) and a developable protective layer (b) laminated on the flexible printed wiring board via the developable adhesive layer (a). A photosensitive resin structure having at least the developable protective layer (b) can be patterned by light irradiation, and the developable adhesive layer (a) and the developable protective layer (b) The pattern can be collectively formed by development.

In particular, it is preferable that both the developable adhesive layer (a) and the developable protective layer (b) can be patterned by light irradiation.

In the photosensitive resin structure of the present invention, it is preferable that the developable adhesive layer (a) is thicker than the developable protective layer (b).

Furthermore, the photosensitive resin structure of the present invention can be used for at least one of a bent portion and a non-bent portion of the flexible printed wiring board, and among the cover lay and the solder resist of the flexible printed wiring board. Can be used to form at least one of the following.

The dry film of the present invention is characterized in that at least one surface of the photosensitive resin structure is supported or protected by a film.

In addition, the flexible printed wiring board of the present invention has a protective film formed by patterning the photosensitive resin structure formed on the flexible printed wiring board by light irradiation and forming the pattern collectively by development. It is a feature.

Preferably, the developable adhesive layer (a) is formed by applying a photosensitive or non-photosensitive resin composition (a1) on a flexible printed wiring board.

In addition, as a result of intensive studies aimed at realizing the above-mentioned other objects, the present inventors have completed the present invention having the following contents.
That is, the laminated structure of the present invention comprises a resin layer (A) made of an alkali developing resin composition, and a resin layer (B) laminated on a flexible printed wiring board via the resin layer (A). The resin layer (B) is composed of a photosensitive thermosetting resin composition containing an alkali-soluble resin having an imide ring, a photobase generator, and a heat-reactive compound. To do.

In the laminated structure of the present invention, it is preferable that both the resin layer (A) and the resin layer (B) can be patterned by light irradiation.

Furthermore, the laminated structure of the present invention can be used for at least one of a bent portion and a non-bent portion of the flexible printed wiring board. Also, the cover lay of the flexible printed wiring board, the solder resist, and the interlayer insulating material Can be used as at least one of the applications.

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

The flexible printed wiring board of the present invention has an insulating film formed by forming a layer of the laminated structure on the flexible printed wiring board, patterning by light irradiation, and forming the pattern in a batch with a developer. It is a feature.
The flexible printed wiring board of the present invention is formed by sequentially forming the resin layer (A) and the resin layer (B) without using the laminated structure according to the present invention, and then patterning by light irradiation. The pattern may be formed in a lump.
In the present invention, the “pattern” means a patterned cured product, that is, an insulating film.

In addition, as a result of intensive studies aimed at realizing the above-described other objects, the present inventors have completed the present invention having the following contents.
That is, in the method for producing a flexible printed wiring board of the present invention, the step of forming at least one resin layer (A) made of an alkali-developable photosensitive resin composition (A1) on the flexible printed wiring board, the resin layer ( A) A step of forming at least one resin layer (B) composed of a photosensitive thermosetting resin composition (B1) containing an alkali-soluble resin having an imide ring, a photobase generator, and a heat-reactive compound. , A step of irradiating the resin layers (A) and (B) formed in the step with light in a pattern, a step of heating the resin layers (A) and (B) irradiated with the light in the step, and A step of alkali-developing the light-irradiated resin layers (A) and (B) to form at least one of a coverlay and a solder resist.

The flexible printed wiring board of the present invention is manufactured by the above manufacturing method.

According to the present invention, it is possible to form a fine pattern on a flexible printed wiring board, and have a photosensitive resin structure excellent in insulation and flexibility, and a cured product thereof as a protective film, for example, a coverlay and a solder resist. A printed wiring board can be provided.

In addition, according to the present invention, the insulating film for flexible printed wiring boards, which has excellent reliability and processing accuracy such as impact resistance, bendability, and low warpage, and excellent workability, particularly a bent portion (bent portion). And a laminated structure suitable for the batch formation process of the mounting part (non-bent part) and its cured product as an insulating film, for example, coverlay, solder resist, interlayer insulating layer, and reliability such as impact resistance and flexibility A flexible printed wiring board having excellent properties can be provided.

Furthermore, according to the present invention, an insulating film for a flexible printed wiring board excellent in reliability and processing accuracy such as impact resistance, bendability, and low warpage, particularly a bent portion (bend portion) and a mounting portion (non- The manufacturing method of the flexible printed wiring board which can form the insulating film in a bending part), for example, a coverlay and a soldering resist, collectively with sufficient workability | operativity, and a flexible printed wiring board can be provided.

It is a schematic sectional drawing of the flexible printed wiring board which laminated | stacked the laminated structure which concerns on one embodiment of this invention. It is a schematic sectional drawing of the flexible printed wiring board after performing patterning and development processing to the laminated structure shown in FIG. It is process drawing which shows typically an example of the manufacturing method of the flexible printed wiring board of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
(Photosensitive resin structure)
The photosensitive resin structure of the present invention can be laminated on a flexible printed wiring board, and can be patterned by light irradiation on the flexible printed wiring board, and a pattern can be collectively formed by development. Is. Here, the pattern means a patterned cured product, that is, a protective film.
Conventionally, after applying an adhesive to a punched coverlay, the coverlay is pressure-bonded on the flexible printed wiring board. In the present invention, the developable adhesive layer (a) and the development are applied on the flexible printed wiring board. After laminating the protective layer (b), it is possible to form a pattern all at once by light irradiation and development.

FIG. 1 shows a photosensitive resin structure according to an embodiment of the present invention.
The structure 1 shown in the figure has a developable adhesive layer (a) and a developable protective layer (b) in this order on a flexible printed wiring board in which a copper circuit 3 is formed on a flexible substrate 2, and at least developable protection. The layer (b) can be patterned by light irradiation, and the developable adhesive layer (a) and the developable protective layer (b) can collectively form a pattern by development. Here, patterning means that a portion irradiated with light changes from a non-developable state to a developable state (positive type) or changes from a developable state to a non-developable state (negative type). To tell. In addition, pattern formation means that a light irradiated part is developed and an unirradiated part remains in a pattern (positive type), or an unirradiated part is developed and a light irradiated part remains in a pattern (negative type). )

In particular, it is preferable that both the developable adhesive layer (a) and the developable protective layer (b) of the photosensitive resin structure of the present invention can be patterned by light irradiation because a fine pattern can be formed.

The developable adhesive layer (a) is formed of a photosensitive or non-photosensitive resin composition (a1), and the developable protective layer (b) is a photosensitive resin composition (b1) different from the resin composition (a1). ).
The photosensitive or non-photosensitive resin composition (a1) is appropriately selected from materials that can impart flexibility to the protective film. In order to form a fine pattern, the resin composition (a1) is preferably photosensitive.
On the other hand, the photosensitive resin composition (b1) is appropriately selected mainly from materials that can impart insulating properties.

In the present invention, the developing adhesive layer (a) is preferably thicker than the developing protective layer (b) from the viewpoint of followability of the protective film to the copper circuit and flexibility. The photosensitive resin structure of the present invention can be used for at least one of a bent portion and a non-bent portion of a flexible printed wiring board. Specifically, the cover lay and the solder of the flexible printed wiring board are used. It can be used to form at least one of the resists. Examples of the non-bent part include a chip mounting part.

The development method may be development using an aqueous alkali solution (hereinafter also referred to as alkali development) or development using an organic solvent, but alkali development is preferred.
The photosensitive resin compositions (a1) and (b1) that can be used for the developable adhesive layer (a) and the developable protective layer (b) may be positive or negative.
As the positive photosensitive composition, a publicly known and conventional one can be used as long as the light irradiation part (also referred to as an exposure part) is dissolved by the developer due to the change in polarity before and after the light irradiation. For example, a composition containing a diazonaphthoquinone compound and an alkali-soluble resin can be mentioned.

As the negative photosensitive composition, a known and commonly used one can be used as long as the light irradiation part is hardly soluble in the developer. Examples thereof include a composition containing a photoacid generator and an alkali-soluble resin, a composition containing a photobase generator and an alkali-soluble resin, and a composition containing a photopolymerization initiator and an alkali-soluble resin.

As a combination of the photosensitive resin compositions (a1) and (b1), the positive photosensitive resin composition (a1), the positive photosensitive resin composition (b1), and the negative photosensitive resin composition (a1) Any combination of negative photosensitive resin composition (b1) may be used.
For example, a composition (a1) containing a photobase generator and a composition (b1) containing a photobase generator,
A composition (a1) containing a photobase generator and a composition (b1) containing a photopolymerization initiator,
A composition (a1) containing a photopolymerization initiator and a composition (b1) containing a photobase generator,
A composition (a1) containing a photopolymerization initiator and a composition (b1) containing a photopolymerization initiator,
The combination can be selected according to the embodiment.

Since the photosensitive resin structure of the present invention is an application of a flexible printed wiring board, it is preferable to be able to reduce distortion and warpage during curing. Accordingly, a composition containing the photobase generator is preferred, and examples of such a composition include a composition containing a photobase generator and a thermosetting resin and cured by an addition reaction.

Further, only one of the photosensitive resin composition (a1) and the photosensitive resin composition (b1) has a photoacid generator, a photobase generator, or a photopolymerization initiator, and the other has a photoacid generator. The structure which does not contain any of a generator, a photobase generator, and a photoinitiator may be sufficient. In this case, the photoacid generator, photobase generator, or photopolymerization initiator contained in one photosensitive resin composition may cure the other photosensitive resin composition.

Moreover, in this invention, the combination of a non-photosensitive resin composition (a1) and a positive photosensitive resin composition (b1) may be sufficient, and a non-photosensitive resin composition (a1) and a negative photosensitive resin composition ( It may be a combination with b1). Moreover, the combination of positive photosensitive resin composition (a1) and non-photosensitive resin composition (b1) may be sufficient, and negative photosensitive resin composition (a1) and non-photosensitive resin composition (b1) A combination may be used. Examples of the non-photosensitive resin composition (a1) include a composition containing a thermosetting resin.

The total film thickness of the laminated structure of the present invention is preferably 100 μm or less, and more preferably in the range of 4 to 80 μm. For example, when the laminated structure has two layers, the developable adhesive layer (a) is, for example, 3 to 60 μm, but is not limited thereto. By setting it as such thickness, a developable contact bonding layer (a) can closely_contact | adhere to a circuit without a gap. On the other hand, the developable protective layer (b) may have a thickness of 1 to 20 μm, for example.

FIG. 2 is a cross-sectional view showing a state where a pattern is formed by irradiating the photosensitive resin structure 1 on the flexible printed wiring board shown in FIG. 1 with light and then developing with an alkaline developer.

(Dry film)
In the dry film of the present invention, at least one surface of the photosensitive resin structure is supported or protected by the film.

For production of the dry film, for example, the photosensitive resin composition (b1) is diluted with an organic solvent to have an appropriate viscosity, and is applied to the carrier film with a uniform thickness using a comma coater or the like. The coating layer is dried to form a developable protective layer (b) on the carrier film. Similarly, a developable adhesive layer (a) can be formed on the developable protective layer (b) with a photosensitive or non-photosensitive resin composition (a1) to obtain the dry film of the present invention. .
A plastic film is used as the carrier film. The thickness of the carrier film is not particularly limited, but is generally appropriately selected within the range of 10 to 150 μm. After forming the photosensitive resin structure on the carrier film, a peelable cover film may be further laminated on the surface of the photosensitive resin structure.

(Flexible printed wiring board)
The flexible printed wiring board of the present invention has a protective film formed by patterning the photosensitive resin structure of the present invention on the flexible printed wiring board by light irradiation and forming the pattern in a lump with a developer. The protective film is preferably at least one of a coverlay and a solder resist.
<Method for producing photosensitive resin structure>
As a method for forming the developable adhesive layer (a) and the developable protective layer (b) on the flexible printed wiring board, the resin compositions (a1) and (b1) can be formed by the laminating method using the dry film of the present invention. The coating method may be used as it is. In the laminating method, a dry film is bonded on the flexible printed wiring board by a laminator or the like so that the developable adhesive layer (a) is in contact with at least one of the bent portion and the non-bent portion of the flexible printed wiring board. .

As a coating method, a photosensitive adhesive composition or a non-photosensitive resin composition (a1) and a photosensitive resin composition (b1) are sequentially applied and dried on a flexible printed wiring board by screen printing or the like, and then a developing adhesive layer. (A) and a developable protective layer (b) are formed.

The resin composition (a1) is applied to a flexible printed wiring board and dried to form a developable adhesive layer (a). From the photosensitive resin composition (b1) on the developable adhesive layer (a). The film which laminates may be formed and the method of forming a developable protective layer (b) may be used.
Conversely, a developable adhesive layer (a) is formed by laminating a film made of the resin composition (a1) on a flexible printed wiring board, and a photosensitive resin composition (a) is formed on the developable adhesive layer (a). The developable protective layer (b) may be formed by applying and drying b1).

<The manufacturing method of the flexible printed wiring board using the negative photosensitive resin structure containing a photoinitiator>
In the case of a negative laminated resin structure containing a photopolymerization initiator, it is sufficient that at least one of the resin composition (a1) and the resin composition (b1) contains a photopolymerization initiator.
In this case, a photosensitive resin structure having a developable adhesive layer (a) and a developable protective layer (b) is formed on the flexible printed wiring board by the laminating method or the like. Thereafter, the negative photosensitive resin structure is irradiated with light in a pattern by a contact method or a non-contact method, and an unirradiated portion is developed to obtain a protective film having a negative pattern. Furthermore, in the case of a composition containing a thermosetting component, for example, by heating to a temperature of about 140 to 180 ° C. and thermosetting, heat resistance, chemical resistance, moisture absorption, adhesion, electrical characteristics, etc. A protective film having excellent characteristics can be formed.
Since the negative photosensitive resin structure contains a photopolymerization initiator, the light irradiation part is cured by radical polymerization.

<The manufacturing method of the flexible printed wiring board using the negative photosensitive resin structure containing a photobase generator>
Also in the case of a negative laminated resin structure containing a photobase generator, at least one of the resin composition (a1) and the resin composition (b1) only needs to contain a photobase generator. Also in this case, first, a negative photosensitive resin structure having a developable adhesive layer (a) and a developable protective layer (b) is formed on the flexible printed wiring board by the laminating method or the like. Thereafter, the negative photosensitive resin structure is irradiated with light in a pattern, thereby generating a base from the photobase generator and curing the light irradiation portion. Thereafter, the unirradiated portion is removed by development to obtain a protective film having a negative pattern. In addition, it is preferable to heat a developable adhesive layer (a) and a developable protective layer (b) after light irradiation.
It is considered that a base is generated in the light irradiation part by light irradiation, the photobase generator is destabilized by the base, and further a base is generated. In this way, the base is chemically propagated, so that the light irradiation part is sufficiently cured to the deep part.

It should be noted that ultraviolet rays may be irradiated after the development in order to further improve the insulation reliability of the protective film. Further, after development, a heat curing (post-cure) step may be further included, and both ultraviolet irradiation and heat curing may be performed after development. The heating temperature in the thermosetting process is, for example, 160 ° C. or higher.

<The manufacturing method of the flexible printed wiring board using the negative photosensitive resin structure containing a photo-acid generator>
Also in the case of a negative laminated resin structure containing a photoacid generator, it suffices that at least one of the resin composition (a1) and the resin composition (b1) contains a photoacid generator. In this case, as in the case of containing a photobase generator, a negative photosensitive resin having a developable adhesive layer (a) and a developable protective layer (b) on the flexible printed wiring board by the laminating method or the like. Form a structure. Thereafter, the negative photosensitive resin structure is irradiated with light in a pattern, thereby generating an acid from the photoacid generator and curing the light irradiation portion. Thereafter, a protective film having a negative pattern is obtained by the same developing method as described above.

<Method for producing flexible printed wiring board using positive photosensitive resin structure>
Also in the case of a positive type laminated resin structure, at least one of the resin composition (a1) and the resin composition (b1) may be a positive type composition. Also in this case, the positive photosensitive resin structure having the developable adhesive layer (a) and the developable protective layer (b) is formed on the flexible printed wiring board by the laminating method or the like.
Then, the polarity is changed by irradiating the positive photosensitive resin structure with light in a pattern. Thereafter, the light irradiation part is developed to obtain a protective film having a positive pattern.

The exposure apparatus used for the light irradiation may be any apparatus that is equipped with a high-pressure mercury lamp lamp, an ultra-high pressure mercury lamp lamp, a metal halide lamp, a mercury short arc lamp, etc., and irradiates ultraviolet rays in the range of 350 to 450 nm. A direct drawing apparatus (for example, a laser direct imaging apparatus that directly draws an image with a laser using CAD data from a computer) can also be used.
As a laser light source of the direct drawing apparatus, either a gas laser or a solid laser may be used as long as laser light having a maximum wavelength in the range of 350 to 450 nm is used. The exposure amount for image formation varies depending on the film thickness and the like, but can generally be in the range of 20 to 1500 mJ / cm ² .

The developing method can be a dipping method, a shower method, a spray method, a brush method or the like, and as a developer, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, Alkaline aqueous solutions such as ammonia and amines can be used.

Next, an embodiment of the laminated structure of the present invention will be described in detail.
(Laminated structure)
The laminated structure of the present invention has a laminated structure having a resin layer (A) made of an alkali developing resin composition and a resin layer (B) laminated on a flexible printed wiring board via the resin layer (A). The resin layer (B) is composed of a photosensitive thermosetting resin composition containing an alkali-soluble resin having an imide ring, a photobase generator, and a heat-reactive compound. is there.

Such a laminated structure of the present invention can be laminated on a flexible printed wiring board, and can be patterned by light irradiation on the flexible printed wiring board, and patterns can be collectively formed by development. It becomes.

According to such a laminated structure of the present invention, (1) a resin having an imide ring in the molecule is used as the resin layer (B), and (2) an alkali-soluble resin and a thermally reactive compound are used. This layer functions as a reinforcing layer by using a composition utilizing the addition reaction, and even if a resin layer (A) made of a conventional solder resist composition or an interlayer insulating material is used, impact resistance and bending It is possible to provide an insulating film for a flexible printed wiring board that is excellent in reliability such as reliability and low warpage and processing accuracy and excellent in workability.

The laminated structure of the present invention has a resin layer (A) and a resin layer (B) in order on a flexible printed wiring board in which a copper circuit is formed on a flexible substrate, and at least the resin layer (B) is irradiated with light. Can be patterned, and the resin layer (A) and the resin layer (B) can collectively form a pattern by development.

(Resin layer (A) constituting the laminated structure)
(Alkali developable resin composition constituting the resin layer (A))
The alkali-developable resin composition constituting the resin layer (A) is a composition containing a resin that contains one or more functional groups among phenolic hydroxyl groups, thiol groups, and carboxyl groups and that can be developed with an alkaline solution. Any photocurable resin composition or thermosetting resin composition may be used. Preferred examples include a resin composition containing a compound having two or more phenolic hydroxyl groups, a carboxyl group-containing resin, a compound having a phenolic hydroxyl group and a carboxyl group, and a compound having two or more thiol groups. It is done.

For example, a light containing a carboxyl group-containing resin or a carboxyl group-containing photosensitive resin, a compound having an ethylenically unsaturated bond, a photopolymerization initiator, and a heat-reactive compound conventionally used as a solder resist composition A curable thermosetting resin composition is mentioned.

Here, as a carboxyl group-containing resin or a carboxyl group-containing photosensitive resin, a compound having an ethylenically unsaturated bond, a photopolymerization initiator, and a heat-reactive compound, known and commonly used ones are used.

(Resin layer (B) constituting the laminated structure)
(Photosensitive thermosetting resin composition constituting the resin layer (B))
The photosensitive thermosetting resin composition constituting the resin layer (B) includes an alkali-soluble resin having an imide ring, a photobase generator, and a heat-reactive compound.

(Alkali-soluble resin having an imide ring)
In the present invention, the alkali-soluble resin having an imide ring is one having an alkali-soluble group such as a carboxyl group or an acid anhydride group and an imide ring. For introducing the imide ring into the alkali-soluble resin, a known and usual method can be used. For example, the resin obtained by making a carboxylic anhydride component react with an amine component and / or an isocyanate component is mentioned. The imidization may be performed by thermal imidization or chemical imidization, and these can be used in combination.

Here, examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydrides and tricarboxylic acid anhydrides, but are not limited to these acid anhydrides, and acid anhydrides that react with amino groups or isocyanate groups. Any compound having a physical group and a carboxyl group can 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) pyro Merit acid dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 4,4′-oxydiphthalic acid Anhydride, 2,2'-difluoro-3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 5,5'-difluoro-3,3', 4,4'-biphenyltetracarboxylic dianhydride Anhydride, 6,6′-difluoro-3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 5,5 ′, 6,6′-hexafluoro-3,3 ′ , 4,4'-biphenylte Lacarboxylic acid dianhydride, 2,2′-bis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 5,5′-bis (trifluoromethyl) -3, 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 6,6′-bis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′ , 5,5′-tetrakis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 6,6′-tetrakis (trifluoromethyl) -3, 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 5,5 ′, 6,6′-tetrakis (trifluoromethyl) -3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride , And 2, 2 ', 5, 5', 6, '-Hexakis (trifluoromethyl) -3,3', 4,4'-biphenyltetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3 ", 4 4 "-terphenyltetracarboxylic dianhydride, 3,3 '", 4,4' "-quaterphenyltetracarboxylic dianhydride, 3,3" ", 4,4" "-kinkphenyltetracarboxylic Acid dianhydride, methylene-4,4′-diphthalic dianhydride, 1,1-ethynylidene-4,4′-diphthalic dianhydride, 2,2-propylidene-4,4′-diphthalic dianhydride 1,2-ethylene-4,4′-diphthalic dianhydride, 1,3-trimethylene-4,4′-diphthalic dianhydride, 1,4-tetramethylene-4,4′-diphthalic acid Dianhydride, 1,5-pentamethylene-4,4'-di Phthalic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, difluoromethylene-4,4′-diphthal Acid dianhydride, 1,1,2,2-tetrafluoro-1,2-ethylene-4,4′-diphthalic dianhydride, 1,1,2,2,3,3-hexafluoro-1, 3-trimethylene-4,4'-diphthalic dianhydride, 1,1,2,2,3,3,4,4-octafluoro-1,4-tetramethylene-4,4'-diphthalic dianhydride 1,1,2,2,3,3,4,4,5,5-decafluoro-1,5-pentamethylene-4,4′-diphthalic dianhydride, thio-4,4′- Diphthalic dianhydride, sulfonyl-4,4′-diphthalic dianhydride, 1,3-bis (3,4-dicarboxyl Nyl) -1,1,3,3-tetramethylsiloxane dianhydride, 1,3-bis (3,4-dicarboxyphenyl) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenyl) ) Benzene dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,3-bis [ 2- (3,4-dicarboxyphenyl) -2-propyl] benzene dianhydride, 1,4-bis [2- (3,4-dicarboxyphenyl) -2-propyl] benzene dianhydride, bis [ 3- (3,4-dicarboxyphenoxy) phenyl] methane dianhydride, bis [4- (3,4-dicarboxyphenoxy) phenyl] methane dianhydride, 2,2-bis [3- (3,4- Dicarboxyphenoxy ) Phenyl] propane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 2,2-bis [3- (3,4-dicarboxyphenoxy) phenyl ] -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, bis (3,4 -Dicarboxyphenoxy) dimethylsilane dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) -1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7- Naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetra Carbo Acid dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic 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 dianhydride, carbonyl-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis (cyclohexane-1) , 2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethynylidene-4,4′-bis (cyclo Xanthane-1,2-dicarboxylic acid) dianhydride, 2,2-propylidene-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1,1,3,3,3 -Hexafluoro-2,2-propylidene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride Thio-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4′-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 3,3 ′ -Difluorooxy-4,4'-diphthalic dianhydride, 5,5'-difluorooxy-4,4'-diphthalic dianhydride, 6,6'-difluorooxy-4,4'-diphthalic acid Anhydride, 3,3 ', 5,5', , 6′-hexafluorooxy-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) 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'-diph Fluorosulfonyl-4,4′-diphthalic dianhydride, 5,5′-difluorosulfonyl-4,4′-diphthalic dianhydride, 6,6′-difluorosulfonyl-4,4′-diphthalic acid Anhydride, 3,3 ′, 5,5 ′, 6,6′-hexafluorosulfonyl-4,4′-diphthalic dianhydride, 3,3′-bis (trifluoromethyl) sulfonyl-4,4 ′ Diphthalic dianhydride, 5,5′-bis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 6,6′-bis (trifluoromethyl) sulfonyl-4,4′-diphthal Acid dianhydride, 3,3 ′, 5,5′-tetrakis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3 ′, 6,6′-tetrakis (trifluoromethyl) Sulfonyl-4,4'-diphthal Acid dianhydride, 5,5 ′, 6,6′-tetrakis (trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3 ′, 5,5 ′, 6,6′-hexakis (Trifluoromethyl) sulfonyl-4,4′-diphthalic dianhydride, 3,3′-difluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 5,5′- Difluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 6,6′-difluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 3 , 3 ′, 5,5 ′, 6,6′-hexafluoro-2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 3,3′-bis (trifluoromethyl) -2 , 2-Perfluoropropylidene-4,4'-diph Luric dianhydride, 5,5′-bis (trifluoromethyl) -2,2-perfluoropropylidene-4,4′-diphthalic dianhydride, 6,6′-difluoro-2,2-par Fluoropropylidene-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'-di Phthalic dianhydride, 9-phenyl-9- (trifluoromethyl) xanthene-2,3,6,7-tetracarboxylic dianhydride, 9,9-bis (trifluoromethyl) xanthene-2,3, 6,7-tetracarboxylic dianhydride, bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 9,9-bis [4- (3 , 4-dicarboxy) phenyl] fluorene dianhydride, 9,9-bis [4- (2,3-dicarboxy) phenyl] fluorene dianhydride, ethylene glycol bistrimellitic dianhydride, 1,2- ( Ethylene) bis (trimellitic anhydride), 1,3- (trimethylene) bis (trimellitic anhydride), 1,4- (tetramethylene) bis (trimellitic anhydride), 1,5- (pentamethylene) bis (to Meritate anhydride), 1,6- (hexamethylene) bis (trimellitic anhydride), 1,7- (heptamethylene) bis (trimellitic anhydride), 1,8- (octamethylene) bis (trimellitic anhydride), 1,9- (nonamethylene) bis (trimellitic anhydride), 1,10- (decamethylene) bis (trimellitic anhydride), 1,12- (dodecamethylene) bis (trimellitic anhydride), 1,16- (hexadeca) Methylene) bis (trimellitate anhydride), 1,18- (octadecamethylene) bis (trimellitate anhydride), and the like.

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

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

Examples of the diamine include p-phenylenediamine (PPD), 1,3-diaminobenzene, 2,4-toluenediamine, 2,5-toluenediamine, 2,6-toluenediamine, 3,5-diaminobenzoic acid, One diamine nucleus diamine such as 2,5-diaminobenzoic acid and 3,4-diaminobenzoic acid, diaminodiphenyl ether such as 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, and 3,4′-diaminodiphenyl ether 4,4′-diaminodiphenylmethane, 3,3′-dimethyl-4,4′-diaminobiphenyl, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-bis (trifluoromethyl ) -4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodi Phenylmethane, 3,3′-dicarboxy-4,4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylmethane, bis (4-aminophenyl) sulfide, 4, 4'-diaminobenzanilide, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (o-tolidine), 2,2'-dimethylbenzidine (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'-diaminodiphenyl Lufone, 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, 3,4′-diaminodiphenyl sulfoxide Hydroxide, 4,4′-diaminodiphenyl sulfoxide, 3,3′-dicarboxy-4,4′-diaminodiphenylmethane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 3,3 ′ -Two diamine diamines such as diamino-4,4'-dihydroxydiphenylsulfone, 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'-di (4-phenylphenoxy) benzophenone, 1,3-bis (3-aminophenyl sulfide) benzene, 1 , 3-bis (4-aminophenylsulfide) benzene, 1,4-bis (4-aminophenylsulfide) benzene, 1,3-bis (3-aminophenylsulfone) benzene, 1,3-bis (4-amino) Phenylsulfone) 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, 1,3-bis (4-a) -3-nucleophenoxy) benzene and other benzene nuclei, 3 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) phenyl] ether, Bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, bis [3- (3-aminophenoxy) phenyl] ketone, bis [3- (4-amino Phenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenyl) Enoxy) 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-amino Phenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) 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] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3 3-hexafluoropropane Aromatic diamines such as four diamines of benzene, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7 Aliphatic diamines such as -diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,2-diaminocyclohexane, etc. Examples of the aliphatic polyether amine include ethylene glycol and / or propylene glycol polyvalent amine.

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

The alkali-soluble resin having an imide ring as described above may have an amide bond. This may be an amide bond obtained by reacting an isocyanate and a carboxylic acid, or may be caused by other reaction. Furthermore, you may have the coupling | bonding which consists of another addition and condensation.

In addition, for the introduction of the imide ring into the alkali-soluble resin, a known and commonly used alkali-soluble polymer, oligomer or monomer having a carboxyl group and / or an acid anhydride group may be used. It may be a resin obtained by reacting an alkali-soluble resin alone or in combination with the above carboxylic anhydride component and reacting with the above amine / isocyanate.

In the synthesis of such an alkali-soluble resin having an alkali-soluble group and an imide ring, a known and commonly used organic solvent can be used. Such an organic solvent is not particularly limited as long as it is a solvent that does not react with the carboxylic acid anhydrides, amines, and isocyanates that are raw materials and that dissolves these raw materials, and the structure is not particularly limited. Specific examples include amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone. Cyclic ester solvents such as α-methyl-γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, lactam solvents such as caprolactam, ether solvents such as dioxane, glycol solvents such as triethylene glycol, m-cresol, phenolic solvents such as p-cresol, 3-chlorophenol, 4-chlorophenol, 4-methoxyphenol, 2,6-dimethylphenol, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl Sulfo Sid, such as tetramethylurea. In addition, other common organic solvents such as phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran , Dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpene, mineral spirit, petroleum naphtha solvents, etc. Can also be used. Of these, aprotic solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, and γ-butyrolactone are preferred because of the high solubility of the raw materials.

The alkali-soluble resin having an alkali-soluble group such as a carboxyl group or an acid anhydride group and an imide ring as described above has an acid value of 20 to 200 mgKOH / g in order to cope with the photolithography process. And more preferably 60 to 150 mgKOH / g. When the acid value is 20 mgKOH / g or more, the solubility in alkali increases, the developability becomes good, and further, the degree of crosslinking with the thermosetting component after light irradiation becomes high, so that sufficient development contrast is obtained. be able to. Moreover, when this acid value is 200 mgKOH / g or less, what is called a heat | fever fog in the PEB (POST EXPOSURE BAKE) process after light irradiation mentioned later can be suppressed, and a process margin becomes large.

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

(Photobase generator)
The photobase generator used in the resin layer (B) is used as a catalyst for the polymerization reaction of a thermoreactive compound, which will be described later, when the molecular structure is changed by light irradiation such as ultraviolet light or visible light, or when the molecule is cleaved. It is a compound that produces one or more basic substances that can function. Examples of basic substances include secondary amines and tertiary amines.
Examples of photobase generators include α-aminoacetophenone compounds, oxime ester compounds, acyloxyimino groups, N-formylated aromatic amino groups, N-acylated aromatic amino groups, nitrobenzyl carbamate groups, alkoxybenzyl carbamates. And compounds having a substituent such as a group. Of these, oxime ester compounds and α-aminoacetophenone compounds are preferred. As the α-aminoacetophenone compound, those having two or more nitrogen atoms are particularly preferable.

As other photobase generators, WPBG-018 (trade name: 9-anthrylmethylN, N′-diethylcarbamate), WPBG-027 (trade name: (E) -1- [3- (2-hydroxyphenyl) -2-propenoyl Piperidine), WPBG-082 (trade name: guanidinium2- (3-benzoylphenyl) propionate), WPBG-140 (trade name: 1- (anthraquinon-2-yl) ethyl imidazole carbonate).

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

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

In addition, JP-A-2004-359639, JP-A-2005-097141, JP-A-2005-220097, JP-A-2006-160634, JP-A-2008-094770, JP-A-2008-509967, Specific examples include carbazole oxime ester compounds described in JP-T-2009-040762 and JP-A-2011-80036.

Such photobase generators may be used alone or in combination of two or more. The blending amount of the photobase generator in the thermosetting resin composition is preferably 0.1 to 40 parts by mass, more preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the thermoreactive compound. It is. In the case of 0.1 parts by mass or more, the development resistance contrast of the light irradiated part / non-irradiated part can be favorably obtained. Moreover, in 40 mass parts or less, hardened | cured material characteristic improves.

(Thermo-reactive compound)
The heat-reactive compound used in the resin layer (B) is a resin having a functional group capable of undergoing a curing reaction by heat, preferably a resin having a cyclic (thio) ether group, more preferably an epoxy resin, Examples include polyfunctional oxetane compounds. The cyclic (thio) ether group means at least one of a cyclic ether group and a cyclic thioether group.

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

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

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

Examples of the polyfunctional oxetane compound include bis [(3-methyl-3-oxetanylmethoxy) methyl] ether, bis [(3-ethyl-3-oxetanylmethoxy) methyl] ether, 1,4-bis [(3-methyl -3-Oxetanylmethoxy) methyl] benzene, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, (3-methyl-3-oxetanyl) methyl acrylate, (3-ethyl-3-oxetanyl) In addition to polyfunctional oxetanes such as methyl acrylate, (3-methyl-3-oxetanyl) methyl methacrylate, (3-ethyl-3-oxetanyl) methyl methacrylate and oligomers or copolymers thereof, oxetane alcohol and novolak resin, Poly (p-hydroxystyrene), cardo-type bisphe Lumpur acids, calixarenes, calix resorcin arenes, or the like ethers of a resin having a hydroxyl group such as silsesquioxane and the like. In addition, a copolymer of an unsaturated monomer having an oxetane ring and an alkyl (meth) acrylate is also included.

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

(Polymer resin)
The resin composition used in the resin layer (A) and the resin layer (B) as described above is blended with a known and commonly used polymer resin for the purpose of improving the flexibility and dryness of the cured product obtained. can do. Examples of such polymer resins include cellulose-based, polyester-based, phenoxy-resin-based polymers, polyvinyl acetal-based, polyvinyl butyral-based, polyamide-based, polyamide-imide-based binder polymers, block copolymers, and elastomers.
This polymer resin may be used individually by 1 type, and may use 2 or more types together.

(Inorganic filler)
In addition, the resin composition used in the resin layer (A) and the resin layer (B) is blended with an inorganic filler in order to suppress curing shrinkage of the cured product and improve properties such as adhesion and hardness. Can do. 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 Sicilius Earth etc. are mentioned.

(Coloring agent)
Furthermore, a well-known and usual colorant can be mix | blended with the resin composition used in the resin layer (A) and the resin layer (B).
Conventionally, at the edge portion of a copper circuit in a printed wiring board, when the coloring power of the pattern layer is insufficient, copper is discolored in the heat history after the formation of the pattern layer, and only a thin portion appears discolored in appearance. Typical thermal history includes marking thermosetting, warping, preheating before mounting, mounting, and the like.
For this reason, conventionally, a problem has been solved that only the edge portion of the copper circuit looks discolored by adding a large amount of colorant to the pattern layer to enhance the coloring power.
However, since the colorant has light absorptivity, it prevents light from penetrating to the deep part. As a result, in a composition containing a colorant, undercut is likely to occur, and it is difficult to obtain sufficient adhesion.

On the other hand, in the resin composition used in the present invention, the base can be sufficiently cured to the deep part of the resin layer by the chemical growth of the base to the deep part.
Therefore, according to the resin composition used in the present invention, even when a colorant is contained, a pattern layer having excellent copper circuit concealing property and excellent adhesion can be formed.

(Organic solvent)
For the resin composition used in the resin layer (A) and the resin layer (B), an organic solvent should be used for preparing the resin composition and adjusting the viscosity for application to a substrate or carrier film. Can do.
Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. Such an organic solvent may be used individually by 1 type, and may be used as a 2 or more types of mixture.

(Other optional ingredients)
The resin composition used in the resin layer (A) and the resin layer (B) can further contain components such as a mercapto compound, an adhesion promoter, an antioxidant, and an ultraviolet absorber as necessary. As these, those commonly used in the field of electronic materials can be used. In addition, known and commonly used thickeners such as finely divided silica, hydrotalcite, organic bentonite, montmorillonite, defoamers and / or leveling agents such as silicones, fluorines and polymers, silane coupling agents, rust inhibitors Known and conventional additives such as can be blended.

Next, an embodiment of the method for producing a flexible printed wiring board of the present invention will be described in detail. The method for producing a flexible printed wiring board of the present invention includes a step of forming at least one resin layer (A) made of an alkali-developable photosensitive resin composition (A1) on the flexible printed wiring board, the resin layer (A) A step of forming at least one resin layer (B) comprising a photosensitive thermosetting resin composition (B1) containing an alkali-soluble resin having an imide ring, a photobase generator, and a thermoreactive compound; A step of irradiating the resin layers (A) and (B) formed in the step with light in a pattern, a step of heating the resin layers (A) and (B) irradiated with the light in the step, and the light A step of alkali-developing the irradiated resin layers (A) and (B) to form at least one of a coverlay and a solder resist.

In the present invention, in the resin layer (B), (1) a resin having an imide ring in the molecule is used, and (2) a composition that causes an addition reaction between an alkali-soluble resin and a thermally reactive compound is used. Thus, the resin layer (B) can function as a reinforcing layer.
That is, by forming a resin layer (A) made of a conventional solder resist composition and laminating the resin layer (B) on the resin layer (A), impact resistance, flexibility, low warpage, etc. A cover lay and a solder resist having excellent reliability and processing accuracy can be collectively formed on a flexible printed wiring board. Note that an interlayer insulating film may be formed as the insulating film.

Hereinafter, an example of the manufacturing method of the flexible printed wiring board of this invention is demonstrated based on FIG.
[Formation step of resin layer (A)]
In this step, at least one resin layer (A) made of the alkali development type photosensitive resin composition (A1) is formed on the flexible printed wiring board. Since the resin layer (A) can be alkali-developed, a pattern can be formed. Further, by laminating the resin layer (A), the circuit followability and the adhesion to the substrate can be improved.
The flexible printed wiring board is obtained by forming a copper circuit 2 on a flexible substrate 1. The position where the resin layer (A) is formed may be one of a bent portion and a non-bent portion, but is preferably both a bent portion and a non-bent portion. The bent portion is a portion that is repeatedly bent and requires flexibility, and the non-bent portion is a portion that is not bent, such as a chip mounting portion.

Examples of the method for forming the resin layer (A) include a coating method and a laminating method.
In the case of the coating method, the alkali-developable photosensitive resin composition (A1) is coated on the flexible printed wiring board by a screen printing method, a curtain coating method, a spray coating method, a roll coating method or the like, and 50 to 130 ° C. The resin layer (A) is formed by heating at about a temperature for about 15 to 60 minutes.
In the case of the laminating method, first, the alkali developing type photosensitive resin composition (A1) is diluted with an organic solvent to adjust to an appropriate viscosity, applied onto a carrier film and dried to have a resin layer (A). Create Next, after bonding together so that a resin layer (A) may contact a flexible printed wiring board with a laminator etc., a carrier film is peeled.

[Formation step of resin layer (B)]
In this step, a resin layer (B) comprising a photosensitive thermosetting resin composition (B1) containing an alkali-soluble resin having an imide ring, a photobase generator, and a heat-reactive compound on the resin layer (A). ) At least one layer. Since the resin layer (B) can be alkali-developed, a fine pattern can be formed and the processing accuracy is excellent. Further, by laminating the resin layer (B), it is possible to improve impact resistance, flexibility and low warpage.
The position where the resin layer (B) is formed is preferably both a bent portion and a non-bent portion on the resin layer (A). However, the resin layer (B) may be formed only on the bent portion or only on the non-bent portion of the resin layer (A).
Further, a further layer may be interposed between the resin layer (B) and the resin layer (A).
The resin layer (B) can be formed by the same method as the method for forming the resin layer (A).
The resin layers (A) and (B) may be formed by laminating the laminated dry film on a flexible printed wiring board after making them into one laminated dry film.
In the present invention, the resin layer (A) is preferably formed thicker than the resin layer (B) from the viewpoint of followability to the copper circuit.

[Light irradiation process]
In this step, the resin layers (A) and (B) are irradiated with light in a negative pattern. By this step, the photobase generator contained in the photosensitive thermosetting resin composition can be activated to cure the light irradiation part. Thus, it is thought that it can fully harden to the deep part of a resin layer by chemically growing to the deep part of a resin layer by generating a base. In subsequent thermosetting, this base acts as a catalyst for the addition reaction between the alkali-developable resin and the heat-reactive compound, and the addition reaction proceeds. Therefore, in the light irradiation part, the resin layer is sufficiently deep. To harden. Thus, since hardening of the curable resin composition in this invention is a ring-opening reaction of the epoxy by thermal reaction, distortion and hardening shrinkage | contraction can be suppressed compared with the case where it progresses by photoreaction.
As a light irradiation device, a direct drawing device (for example, a laser direct imaging device that directly draws an image with a laser using CAD data from a computer), a light irradiation device equipped with a metal halide lamp, or a light irradiation device equipped with a (ultra) high pressure mercury lamp In addition, a light irradiator equipped with a mercury short arc lamp or a direct drawing apparatus using an ultraviolet lamp such as a (super) high pressure mercury lamp can be used.

As the active energy ray used for light irradiation, it is preferable to use laser light or scattered light having a maximum wavelength in the range of 350 to 450 nm. The amount of light irradiation varies depending on the film thickness and the like, but can generally be in the range of 50 to 1500 mJ / cm ² , preferably 100 to 1000 mJ / cm ² .

[Heating process]
In this step, the resin layers (A) and (B) are heated. Thereby, it can fully harden | cure to a deep part with the base generate | occur | produced by light irradiation. This process is a so-called PEB (POST EXPOSURE BAKE) process.
The heating temperature is preferably a temperature at which the light-irradiated portion of the thermosetting resin composition is thermally cured, but the non-irradiated portion is not thermally cured.
For example, the heating step is a temperature lower than the heat generation start temperature or the heat generation peak temperature of the unirradiated thermosetting resin composition and higher than the heat generation start temperature or the heat generation peak temperature of the light irradiated thermosetting resin composition. It is preferable to heat with. By heating in this way, only the light irradiation part can be selectively cured.
The heating temperature is, for example, 80 to 140 ° C. By setting the heating temperature to 80 ° C. or higher, the light irradiation part can be sufficiently cured. On the other hand, by setting the heating temperature to 140 ° C. or lower, only the light irradiation part can be selectively cured. The heating time is, for example, 10 to 100 minutes. In the unirradiated portion, no base is generated from the photobase generator, so that thermosetting is suppressed.

[Development process]
In this step, the resin layers (A) and (B) irradiated with light are developed to form at least one of a coverlay and a solder resist. By this development, a patterned coverlay and solder resist can be obtained in a lump.
The development method is alkali development, and can be performed by a known method such as a dipping method, a shower method, a spray method, or a brush method.
Examples of the alkaline developer include potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, ethanolamine, amines such as imidazole, tetramethylammonium hydroxide aqueous solution (TMAH), etc. An alkaline aqueous solution or a mixed solution thereof can be used.

[Other processes]
In the present invention, the following steps may be added as necessary.
(Second light irradiation process)
After the development step, the resin layers (A) and (B) may be irradiated with light. By this light irradiation, the photobase generator remaining without being activated in the resin layer (B) in the previous light irradiation step is activated to sufficiently generate a base.
The wavelength of ultraviolet rays and the light irradiation amount (exposure amount) in this light irradiation may be the same as or different from those in the light irradiation step. The light irradiation amount is, for example, 150 to 2000 mJ / cm ² .

(Thermosetting process)
Further, after the development step, the resin layers (A) and (B) may be further thermally cured (post-cured) by heating. In this thermosetting step, the pattern layer is sufficiently thermoset by the light irradiation step or the base generated from the photobase generator in the light irradiation step and the second light irradiation step. Since the unirradiated part has already been removed at the time of the thermosetting process, the thermosetting process can be performed at a temperature equal to or higher than the curing reaction start temperature of the unirradiated thermosetting resin composition. By thermosetting, the resin layers (A) and (B) can be sufficiently thermoset. The heating temperature is, for example, 150 ° C. or higher.

Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to the following examples.

(Examples 1 and 2, Comparative Examples 1 and 2)
Various components shown in Table 1 below were blended in the proportions (parts by mass) shown in Table 1, premixed with a stirrer, and then kneaded with a three-roll mill to prepare a photosensitive resin composition.

* 1: Carboxyl group-containing cresol novolac epoxy acrylate (manufactured by DIC Corporation)
* 2: Dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.)
* 3: Bisphenol A type novolak epoxy resin (manufactured by DIC Corporation)
* 4: Tetramethylbiphenyl type epoxy resin (Mitsubishi Chemical Corporation)
* 5: Aminoalkylphenone photopolymerization initiator (BASF Japan Ltd.)
* 6: Diethylthioxanthone sensitizer (manufactured by Nippon Kayaku Co., Ltd.)
* 7: Barium sulfate (manufactured by Sakai Chemical Industry Co., Ltd.)
* 8: Polyimide film (manufactured by Toray DuPont Co., Ltd.)
* 9: Carboxyl group-containing bisphenol F type epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd.)
* 10: Trimethylolpropane EO-modified triacrylate (manufactured by Toagosei Co., Ltd.)
* 11: Bisphenol A type epoxy resin (molecular weight: 1600) (Mitsubishi Chemical Corporation)
* 12: Bisphenol A type epoxy resin (Molecular weight: 900) (Mitsubishi Chemical Corporation)
* 13: Bisphenol A type epoxy resin (Molecular weight: 500) (Mitsubishi Chemical Corporation)
* 14: Ethylmethylimidazole (manufactured by Shikoku Chemicals Co., Ltd.)

(Example 1)
For Example 1, the laminating method was used. In Example 1, after the photosensitive resin composition for (b) layer was applied to a carrier film and dried to form a developable protective layer, the photosensitive resin composition for (a) layer was formed on the surface. Was applied and dried to obtain a dry film. The dry film was pressure-bonded to a flexible printed wiring board at 120 ° C. to form a photosensitive resin structure. Table 1 shows the film thickness.
(Example 2)
For Example 2, the whole surface printing method was used, and after the photosensitive resin composition for layer (a) was applied on a flexible printed wiring board and dried, the photosensitive resin composition for layer (b) was applied to the surface. Application and drying were performed to form a photosensitive resin structure. Each film thickness is shown in Table 1.
(Comparative Example 1)
About the comparative example 1, the whole surface printing method was used, the photosensitive resin composition for (b) layer was apply | coated and dried on the flexible printed wiring board, and the flexible printed wiring board only of (b) layer was obtained. Table 1 shows the film thickness.
(Comparative Example 2)
For Comparative Example 2, the whole surface printing method was used, and the photosensitive resin composition for (a) layer was applied onto the flexible printed wiring board and dried to obtain a flexible printed wiring board having only the (a) layer. Table 1 shows the film thickness.
(Comparative Example 3)
For Comparative Example 3, the laminating method was used. In Comparative Example 3, the resin for (a) layer was applied to a polyimide film having an opening pattern of 5 mm × 5 mm formed by punching, dried, and then pressed onto a flexible printed wiring board at 120 ° C. Thereby, the flexible printed wiring board which has a pattern was obtained. The film thickness is shown in Table 1.
(Comparative Example 4)
In Comparative Example 4, a pattern printing method is used, and a resin for layer (b) is applied and dried on a flexible printed wiring board by pattern printing with an opening of 5 mm × 5 mm, and (b) a flexible printed wiring board having a pattern of only the layer Got. Table 1 shows the film thickness.

<Alkali developability test>
The photosensitive resin structures of Examples 1 and 2 and Comparative Examples 1 and ² were irradiated with light at an exposure amount of 500 mJ / cm ² through a negative mask using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp. Then, development (30 ° C., 0.2 MPa, 1 mass% sodium carbonate aqueous solution) was carried out to examine whether alkali development was possible.

<Flexibility test>
For the photosensitive resin structures of Examples 1 and 2 and the resin layers of Comparative Examples 1 and 2, a pattern having an opening (5 × 5 mm) was formed by light irradiation and development as in the alkali developability test. did.
The flexible printed wiring boards having the patterns of Examples 1 and 2 and Comparative Examples 1 to 4 were bent 180 °. The case where no crack occurred was considered good, and the case where no crack occurred was regarded as defective.

<Electrical characteristics test>
Patterns of Examples 1 and 2 and Comparative Examples 1 to 4 were applied to a flexible printed wiring board on which comb-shaped electrodes (line / space = 100 μm / 100 μm) were formed by light irradiation and development in the same manner as in the alkali developability test. To form an evaluation substrate. This evaluation board | substrate was put into the high-temperature, high-humidity tank of the atmosphere of 130 degreeC and humidity 85%, the voltage 50V was charged, and the in-chamber HAST test was done for 1000 hours. A case where no short circuit occurred was considered good, and a case where a short circuit occurred was regarded as defective.

<Opening bleeding test>
For the photosensitive resin structures of Examples 1 and 2 and the resin layers of Comparative Examples 1 and 2, a pattern having an opening (5 × 5 mm) was formed by light irradiation and development as in the alkali developability test. did.
The patterns of Examples 1 and 2 and Comparative Examples 1 to 4 were evaluated for the presence or absence of oozing into the opening (5 × 5 mm). Table 2 shows the results of the evaluation tests.

From the results shown in Table 2 above, it was found that the photosensitive resin structures of Examples 1 and 2 can form a fine pattern by development on a flexible printed wiring board. Moreover, it turned out that the protective film of Example 1, 2 is excellent also in flexibility and electrical insulation.
On the other hand, the protective film of Comparative Example 1 did not provide flexibility, and the protective film of Comparative Example 2 had insufficient insulation. On the other hand, it was found that the protective films of Comparative Examples 3 and 4 were not suitable for forming a fine pattern because bleeding to the opening occurred on the flexible printed wiring board.

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

(Examples 3 and 4 and Comparative Example 5)
Synthesis example: <Synthesis of imide ring / carboxyl group-containing resin>
12.2 g of 3,5-diaminobenzoic acid, 2,2′-bis [4- (4-aminophenoxy) in a separable three-necked flask equipped with a stirrer, nitrogen inlet tube, fractional ring, and cooling ring Phenyl] propane 8.2 g, NMP 30 g, γ-butyrolactone 30 g, 4,4′-oxydiphthalic anhydride 27.9 g and trimellitic anhydride 3.8 g were added at room temperature under a nitrogen atmosphere at 100 rpm. Stir for 4 hours. Next, 20 g of toluene was added and stirred for 4 hours while distilling off toluene and water at a silicon bath temperature of 180 ° C. and 150 rpm to obtain a polyimide solution.
<Preparation of resin composition constituting each resin layer>
In accordance with the formulation shown in Table 3 below, the materials described in Examples and Comparative Examples were respectively blended, premixed with a stirrer, and then kneaded with a three-roll mill to prepare resin compositions constituting each resin layer. . The values in the table are parts by mass unless otherwise specified.

<Formation of resin layer (A)>
A flexible printed wiring substrate on which a circuit having a copper thickness of 18 μm was formed was prepared, and pre-treatment was performed using MEC CZ-8100. Thereafter, the pre-treated flexible printed wiring board was coated with the resin compositions of Examples 3 and 4 and Comparative Example 5 by a coating method shown in Table 3 so that the film thickness was 25 μm after drying. Went. Then, it dried at 90 degreeC / 30 minutes with the hot-air circulation type drying furnace, and formed the resin layer (A) which consists of a resin composition.

<Formation of resin layer (B)>
On the resin layer (A) formed as described above, the resin compositions of Examples 3 and 4 were coated by the coating method shown in Table 3 so as to be 10 μm after drying. Then, it dried at 90 degreeC / 30 minutes with the hot-air circulation type drying furnace, and formed the resin layer (B) which consists of a resin composition. In Comparative Example 1, the resin layer (B) was not formed.

<Developability (patterning) and evaluation of curing characteristics>
In Examples 3 and 4, with respect to the flexible printed wiring board provided with the resin layers (A) and (B) obtained above, the exposure amount shown in Table 3 with ORC HMW680GW (metal halide lamp, scattered light) Light was irradiated in a negative pattern. Next, heat treatment was performed at 90 ° C. for 60 minutes. Thereafter, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30 ° C. and developed for 3 minutes to evaluate the developability. In Comparative Example 5, the possibility of developability was evaluated in the same manner as in Example 3 for the flexible printed wiring board provided with the resin layer (A) obtained above. The obtained results are shown in Table 3.

Next, heat treatment was performed at 150 ° C./60 minutes using a hot air circulation drying oven to obtain a patterned cured coating film. An MIT test (R = 0.38 mm / Upilex 12.5 μm base material used) and a surface hardness test (pencil hardness test) were conducted on the obtained cured coating film, and the flexibility and surface Hardness was evaluated. The results obtained are shown in Table 3 below.

* 11: Acid value 86 mgKOH / g MW: 10,000
* 12: Bisphenol A type epoxy resin (Molecular weight: 380) (Mitsubishi Chemical Corporation)
* 13: Oxime type photopolymerization initiator (manufactured by BASF Japan Ltd.)
* 14: Bisphenol F type epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd.)
* 15: Trimethylolpropane EO-modified triacrylate (manufactured by Toagosei Co., Ltd.)
* 16: Bisphenol A epoxy resin (molecular weight: 900) (Mitsubishi Chemical Corporation)
* 17: Bisphenol A epoxy resin (molecular weight: 500) (Mitsubishi Chemical Corporation)
* 18: Acylphosphine oxide photopolymerization initiator (BASF Japan Ltd.)

As is apparent from the evaluation results shown in Table 3, the flexible printed wiring boards of Examples 3 and 4 can be developed in the same manner as the flexible printed wiring board of Comparative Example 5, and the flexibility and surface hardness are greatly increased. It turns out that it is excellent.

DESCRIPTION OF SYMBOLS 1 Photosensitive resin structure 2 Flexible base material 3 Copper circuit a Developable adhesive layer b Developable protective layer 11 Flexible printed wiring base material 12 Copper circuit 13 Resin layer 14 Resin layer 15 Mask

Claims (16)

1. A developable adhesive layer (a);
   A developable protective layer (b) laminated on the flexible printed wiring board via the developable adhesive layer (a), and a photosensitive resin structure comprising:
   At least the developable protective layer (b) can be patterned by light irradiation, and the developable adhesive layer (a) and the developable protective layer (b) collectively form a pattern by development. A photosensitive resin structure characterized in that
2. The photosensitive resin structure according to claim 1, wherein both the developable adhesive layer (a) and the developable protective layer (b) can be patterned by light irradiation.
3. The photosensitive resin structure according to claim 1, wherein the developable adhesive layer (a) is thicker than the developable protective layer (b).
4. The photosensitive resin structure according to claim 1, wherein the photosensitive resin structure is used for at least one of a bent portion and a non-bent portion of the flexible printed wiring board.
5. The photosensitive resin structure according to claim 1, which is used for forming at least one of a cover lay and a solder resist of a flexible printed wiring board.
6. A dry film, wherein at least one surface of the photosensitive resin structure according to claim 1 is supported or protected by a film.
7. A flexible printed wiring comprising a protective film formed by patterning the photosensitive resin structure according to claim 1 formed on a flexible printed wiring board by light irradiation and forming the pattern collectively by development. Board.
8. The flexible printed wiring board according to claim 7, wherein the developable adhesive layer (a) is formed by applying a photosensitive or non-photosensitive resin composition (a1) on the flexible printed wiring board.
9. A resin layer (A) comprising an alkali developing resin composition;
   A resin layer (B) laminated on the flexible printed wiring board via the resin layer (A);
   A laminated structure comprising:
   The said resin layer (B) consists of a photosensitive thermosetting resin composition containing the alkali-soluble resin which has an imide ring, a photobase generator, and a thermoreactive compound, The laminated structure characterized by the above-mentioned.
10. The laminated structure according to claim 9, wherein both the resin layer (A) and the resin layer (B) can be patterned by light irradiation.
11. The laminated structure according to claim 9, which is used for at least one of a bent portion and a non-bent portion of the flexible printed wiring board.
12. The laminated structure according to claim 9, which is used as at least one of a cover lay, a solder resist, and an interlayer insulating material of a flexible printed wiring board.
13. A dry film characterized in that at least one surface of the laminated structure according to claim 9 is supported or protected by a film.
14. A flexible printed circuit board comprising: an insulating film formed on the flexible printed wiring board by forming a layer of the laminated structure according to claim 9, patterning by light irradiation, and forming a pattern in a batch with a developer; Printed wiring board.
15. A step of forming at least one resin layer (A) made of the alkali-developable photosensitive resin composition (A1) on the flexible printed wiring board;
    On the resin layer (A), at least a resin layer (B) comprising a photosensitive thermosetting resin composition (B1) containing an alkali-soluble resin having an imide ring, a photobase generator, and a heat-reactive compound. A step of forming one layer,
    Irradiating the resin layers (A) and (B) formed in the step with light in a pattern;
    Heating the resin layers (A) and (B) irradiated with light in the step; and
    A step of alkali-developing the light-irradiated resin layers (A) and (B) to form at least one of a coverlay and a solder resist;
    The manufacturing method of the flexible printed wiring board characterized by including.
16. A flexible printed wiring board manufactured by the method for manufacturing a flexible printed wiring board according to claim 15.

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