TWI614571B - Laminated structure, flexible printed wiring board and method of manufacturing same - Google Patents

Abstract

The present invention provides a photosensitive resin structure capable of forming a fine pattern on a flexible printed wiring board, and having excellent insulation and bendability, and a hardened material as a protective film such as a coverlay or a solder resist. Flexible printed wiring board.

The photosensitive resin structure of the present invention is characterized by having a developable adhesive layer (a) and a developable protective layer (b) laminated on the flexible printed wiring board via the developable adhesive layer (a). ), At least the above-mentioned developing protective layer (b) can be patterned by light irradiation, and the above-mentioned developing adhesive layer (a) and the above-mentioned developing protective layer (b) are patterned. The pattern can be formed at one time by developing.

Description

Laminated structure, flexible printed wiring board, and manufacturing method thereof

The present invention relates to a laminated structure, particularly a photosensitive resin structure, a dry film using the same, and a flexible printed wiring board. Specifically, the present invention relates to a structure capable of forming a fine pattern on a flexible printed wiring board. A photosensitive resin structure, and a flexible printed wiring board having the cured product as a protective film such as a cover film or a solder resist, and a method for producing the same.

Conventionally, as a protective film for a flexible printed wiring board, a non-photosensitive resin structure obtained by applying a thermosetting adhesive to a film such as polyimide has been used. The method of patterning the non-photosensitive resin structure and forming it on a flexible printed wiring board has conventionally been a method of hot pressing the flexible printed wiring board after performing hole processing by punching. Alternatively, a solvent-soluble thermosetting resin composition is directly pattern-printed on a flexible printed wiring board, and a pattern is formed by heat curing. In particular, a polyimide film has flexibility on the one hand, and excellent heat resistance, mechanical properties, and electrical properties on the other hand, so it can be used as a preferred material for a flexible printed wiring board (see, for example, Patent Document 1).

However, the past method described above is due to the pattern end being coated Resin oozing out at the time of heat or pressure bonding causes the shape to collapse, so it is difficult to form fine patterns required for miniaturization of wiring or miniaturization of chip components mounted on flexible printed wiring boards.

On the other hand, in recent years, electronic devices have become small and thin due to the spread of smart phones or tablet terminals. Therefore, the downsizing of circuit boards has become necessary. Therefore, the use of the flexible printed wiring board which can be flexibly accommodated is expanded, and the reliability of the flexible printed wiring board is also required to be higher than that so far.

In contrast, currently used as an insulating film for ensuring the reliability of insulation of flexible printed matching boards, it is widely used in bending parts (curved parts). Polyurethane, which has excellent mechanical properties such as heat resistance and bendability, is used. An amine is used as a base cover film (refer to, for example, Patent Documents 2 and 3), and a mounting process (a non-bent portion) is used in a mounting process (non-curved portion) using a micro-processable photosensitive resin composition that is excellent in electrical insulation and soldering heat resistance.

However, a cover film based on polyimide, which is excellent in mechanical properties such as heat resistance and bendability, needs to be stamped with a die, and is not suitable for fine wiring. Therefore, the wafer mounting portion requiring fine wiring must be partially combined with an alkali developing type photosensitive resin composition (solder resist) that can be processed by lithography.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: WO2012 / 133665

Patent Document 2: Japanese Patent Application Laid-Open No. 62-263692

Patent Document 3: Japanese Patent Application Laid-Open No. 63-110224

According to this, the manufacturing steps of the flexible printed wiring board cannot adopt the mixed loading process of the step of laminating the cover film and the step of forming the solder resist, and there are problems of cost and poor workability.

For this mixed process, it has been proposed in the past to use an insulating film as a solder resist as a cover film for a flexible printed wiring board. However, in a photosensitive solder resist for a flexible printed wiring board, in order to impart flexibility, it is necessary to reduce the cross-linking density or to add an elastic component. Therefore, electrical reliability, impact resistance, and bendability are reduced. The performance is worse than the thermosetting protective film. Therefore, the one-time forming process of the bent portion (curved portion) and the mounting portion (non-curved portion) has not yet been put into practical use. In addition, since the resin composition for a solder resist is hardened and contracted along with acrylic photopolymerization, there is also a problem of dimensional stability such as warpage of a flexible wiring board.

On the other hand, as a photosensitive polyimide that can have both alkali solubility and mechanical properties, a method of using a polyimide precursor to thermally close the ring after patterning has been proposed in the past. However, there are still problems in the workability of manufacturing wiring boards that require high-temperature processing, etc., and they have not been put to practical use.

In addition, it is also considered to use an insulating film as a cover film as a solder resist for a flexible printed wiring board. However, the film for the cover film requires complicated steps in pattern formation, and the holes caused by patterning etc. machining There is a problem that the resin oozes out when the accuracy is reduced or is hot-pressed, and it is difficult to cope with the formation of fine patterns.

It is therefore an object of the present invention to provide a photosensitive resin structure capable of forming a fine pattern on a flexible printed wiring board, and having excellent insulation and bendability, and a hardened material as a protective film such as a cover film or a solder resist. Flexible printed wiring board.

In addition, another object of the present invention is to provide an insulating film for a flexible printed wiring board, which is excellent in reliability, processing accuracy, and excellent workability, such as impact resistance, bendability, and low warpage, and is particularly suitable for bending. Laminated structure (folded part) and mounting part (non-bent part) are laminated structures with a one-time manufacturing process, and have excellent reliability such as impact resistance or bendability that has a hardened material as a protective film such as a cover film or solder resist Flexible printed wiring board.

In addition, another object of the present invention is to provide an insulating film for a flexible printed wiring board having excellent workability, excellent reliability such as impact resistance, bendability, and low warpage at one time, and excellent processing accuracy. It is a method of manufacturing a flexible printed wiring board with an insulating film such as a cover film or a solder resist in the bent portion (curved portion) and the mounting portion (non-curved portion), and the flexible printed wiring board.

As a result of an active review by the present inventors in order to achieve the above-mentioned object, it was found that the protective film of a flexible printed wiring board is a structure obtained by laminating a plurality of layers of a photosensitive resin structure with a photosensitive resin structure The foregoing objects are achieved so that the present invention is completed.

That is, the photosensitive resin structure of the present invention is characterized by having a developable adhesive layer (a) and a developable protection layer laminated on the flexible printed wiring board via the developable adhesive layer (a). The photosensitive resin structure of the layer (b); at least the above-mentioned developable protective layer (b) is capable of being patterned by light irradiation, and the aforementioned developability is followed by the layer (a) and the aforementioned developability The protective layer (b) is capable of forming a pattern at one time by developing.

In particular, it is preferred that the imageable adhesive layer (a) and the imageable protective layer (b) can be patterned together 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).

In addition, 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, and can be used to form a cover film and a solder resist of the flexible printed wiring board. At least one of them.

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

In addition, the flexible printed wiring board of the present invention is characterized by having a protective film, and the protective film is patterned by light irradiation on the photosensitive resin structure formed on the flexible printed wiring board, and It is formed by developing a pattern at one time.

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

In addition, as a result of intensive studies by the present inventors to achieve other purposes, the present invention has been completed with the following main points as the main points.

That is, the laminated structure of the present invention is characterized by having a resin layer (A) composed of an alkali-developing resin composition, and a layer laminated on a flexible printed wiring board via the resin layer (A). Laminated structure of a resin layer (B); the resin layer (B) is a photosensitive thermosetting resin composition containing an alkali-soluble resin having a fluorene imine ring, a photo-alkali generator, and a heat-reactive compound. Constructor.

The laminated structure of the present invention is preferably one in which the resin layer (A) and the resin layer (B) can be patterned together by light irradiation.

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

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

The flexible printed wiring board of the present invention is characterized by having an insulating film. The insulating film forms a layer of the aforementioned laminated structure on the flexible printed wiring board, and is patterned by light irradiation. A pattern is formed in the image liquid at one time.

The flexible printed wiring board of the present invention can also sequentially form the resin layer (A) and the resin layer (B) without using the laminated structure of the present invention, and then patterning by light irradiation to develop a developing solution. Create a pattern at once.

The "pattern" in the present invention refers to a hardened product in a pattern, and That is, an insulating film.

In addition, the present inventors have actively researched to achieve the other objects described above, and have completed the present invention with the following main points.

That is, the method for manufacturing a flexible printed wiring board of the present invention is characterized by including the steps of forming at least one layer of a resin composed of an alkali-developing photosensitive resin composition (A1) on the flexible printed wiring board. In the step of layer (A), at least one layer of a photosensitive thermosetting resin composition comprising an alkali-soluble resin having a fluorene imine ring, a photo-alkali generator, and a heat-reactive compound is formed on the resin layer (A). (B1) A step of forming the resin layer (B), a step of irradiating light into a pattern on the resin layers (A) and (B) formed in the foregoing step, and heating the light-irradiated portion in the foregoing step. The steps of the resin layers (A) and (B), and the step of alkali developing the resin layers (A) and (B) irradiated with light to form at least one of a cover film and a solder resist.

The flexible printed wiring board of this invention is characterized by being manufactured by the said manufacturing method.

According to the present invention, it is possible to provide a photosensitive resin structure capable of forming a fine pattern on a flexible printed wiring board, and having excellent insulation and bendability, and a hardened material as a protective film, such as a cover film or a solder resist. Flexible printed wiring board

In addition, according to the present invention, it is possible to provide an excellent reliability and processing accuracy such as impact resistance, bendability, and low warpage, and excellent workability. An insulating film for a flexible printed wiring board, particularly a laminated structure suitable for a one-time forming process of a bent portion (bent portion) and a mounting portion (non-bent portion), and having a cured material as an insulating film, for example Flexible printed wiring boards with excellent reliability such as cover films, solder resists, and interlayer insulation films, such as impact resistance and bendability.

Furthermore, according to the present invention, it is possible to provide an insulating film for a flexible printed wiring board having good workability, excellent reliability such as impact resistance, bendability, and low warpage at one time, and excellent processing accuracy. It is a method for manufacturing a flexible printed wiring board, such as a cover film or a solder resist, for an insulating film in a bent part (bent part) and a mounting part (non-bent part), and a flexible printed wiring board.

1‧‧‧ photosensitive resin structure

2‧‧‧ flexible substrate

3‧‧‧copper circuit

a‧‧‧Imaging layer

b‧‧‧ Imaging protective layer

11‧‧‧ Flexible printed wiring substrate

12‧‧‧copper circuit

13‧‧‧resin layer

14‧‧‧ resin layer

15‧‧‧Mask

FIG. 1 is a schematic cross-sectional view of a flexible printed wiring board in which a laminated structure is laminated according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a flexible printed wiring board obtained by subjecting the laminated structure shown in FIG. 1 to patterning and development processing.

FIG. 3 is a step diagram schematically showing an example of a method for manufacturing a flexible printed wiring board according to the present invention.

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

(Photosensitive resin structure)

The photosensitive resin structure of the present invention means that it can be laminated on a flexible printed wiring board, and can be patterned by irradiating light onto the flexible printed wiring board, and can be formed into a pattern at one time by imaging. By. Here, the pattern refers to a patterned hardened material, that is, a protective film.

In the past, an adhesive was applied to a patterned cover film, and then the cover film was pressed against a printed wiring board. However, the present invention can form a developing adhesive layer (a) and a developing protective layer. (b) After being laminated on a flexible printed wiring board, a pattern is formed at one time 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 is a flexible printed wiring board on which a copper circuit 3 is formed on a flexible substrate 2 and has a developable adhesive layer (a) and a developable protective layer (b) in this order, and The pattern of the developable protective layer (b) is irradiated with light at least, and the developable adhesive layer (a) and the developable protective layer (b) can be formed at once by developing. Here, the term "patternization" means that the light-irradiated part is converted from a non-imaging state to a developable state (positive type), or a self-imaging state is converted to a non-degradable state (negative type). And, the formation of a pattern means that the light-irradiated part is developed and the unirradiated part remains as a pattern (positive type), or the unirradiated part is developed and the light-irradiated part remains as a pattern (negative type) .

In particular, when 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, it is preferable to form a fine pattern.

The developable adhesive layer (a) is made of a photosensitive or non-photosensitive resin composition (a1), and the developable protective layer (b) is made of a photosensitive resin composition (a) different from the resin composition (a1) ( b1) formation.

The photosensitive or non-photosensitive resin composition (a1) is mainly appropriately selected from a material capable of imparting flexibility to a 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 mainly appropriately selected from materials that can provide insulation.

In the present invention, from the viewpoint of followability and bendability of the copper circuit of the protective film, the developable adhesive layer (a) is preferably thicker than the developable protective layer (b). In addition, 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, and specifically, can be used to form a cover film for a flexible printed wiring board. And at least one of the solder resist. The non-bent portion is exemplified as a mounting portion of a wafer.

The development method can be developed using an alkaline aqueous solution (hereinafter, also referred to as alkali development) or organic solvents, but it is preferable to use an alkali development.

The photosensitive resin compositions (a1) and (b1) that can be used in the developable adhesive layer (a) and the developable protective layer (b) may be positive or negative.

If the positive-type photosensitive composition changes the polarity before and after light irradiation, and the light-irradiating part (also referred to as the exposure part) can be dissolved by the developing solution, a conventional person can be used. Examples of the composition include a diazonaphthoquinone compound and an alkali-soluble resin.

As the negative photosensitive composition, if the light-irradiating portion is hardly soluble in the developing solution, a conventional user can be used. Examples 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.

The resistance of the photosensitive resin composition (a1) and (b1) may also be a positive photosensitive resin composition (a1), a positive photosensitive resin composition (b1), or a negative photosensitive resin composition (a1). Any one of a combination with the negative photosensitive resin composition (b1).

For example, a combination of 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 containing a photopolymerization initiator ( a combination of b1), a composition (a1) containing a photopolymerization initiator and a composition (b1) containing a photobase generator, a composition (a1) containing a photopolymerization initiator, and a photopolymerization initiation The combination of the composition (b1) of the agent and the like can be selected according to the embodiment.

Since the photosensitive resin structure of the present invention is used for a flexible printed wiring board, it is preferably one that can reduce deformation and warpage during curing. Accordingly, a composition containing the above-mentioned photo-alkali generator is preferable. As such a composition, for example, a composition containing a photo-alkali generator and a thermosetting resin and hardened by an addition reaction is also included.

Moreover, it may be only the photosensitive resin composition (a1) and Either the photoresist composition (b1) has a photoacid generator, a photobase generator, or a photopolymerization initiator, and the other does not contain a photoacid generator, a photobase generator, and a photopolymerization initiator. The composition of any one of the agents. In this case, the photoacid generator, photobase generator, or photopolymerization initiator contained in one photosensitive resin composition may be used to harden the other photosensitive resin composition.

In addition, the present invention may be a combination of a non-photosensitive resin composition (a1) and a positive-type photosensitive resin composition (b1), or a non-photosensitive resin composition (a1) and a negative-type photosensitive resin composition ( b1). In addition, it may be a combination of the positive photosensitive resin composition (a1) and the non-photosensitive resin composition (b1), or it may be the negative photosensitive resin composition (a1) and the non-photosensitive resin composition (b1). Of combination. The non-photosensitive resin composition (a1) is 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 layered structure has two layers, the developability adhesive layer (a) is, for example, 3 to 60 μm, but is not limited thereto. With this thickness, the developable adhesive layer (a) can be closely adhered to the circuit without gaps. On the other hand, the developable protective film (b) only needs to have a thickness of, for example, 1 to 20 μm.

FIG. 2 is a cross-sectional view showing a state in which the photosensitive resin structure 1 shown in FIG. 1 is irradiated with light and subjected to a development treatment with an alkali developer to form a pattern.

(Dry film)

The dry film of the present invention is one in which at least one side of the photosensitive resin structure is supported or protected by the film.

The dry film is produced, for example, by diluting the photosensitive resin composition (b1) with an organic solvent, adjusting the viscosity to an appropriate viscosity, and coating the carrier film with a uniform thickness using a notch wheel coater or the like. This coating layer is dried to form a developable protective layer (b) on the carrier film. Similarly, a developable adhesive layer (a) is formed on the developable protective layer (b) with a photosensitive or non-photosensitive resin composition (a1) to obtain a dry film of the present invention.

The carrier film is a plastic film. The thickness of the carrier film is not particularly limited, but is generally appropriately selected within a range of 10 to 150 μm. After forming the photosensitive resin structure on the carrier film, a peelable protective film may be 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 by irradiating light on the flexible printed wiring board, and forming a pattern with a developing solution at a time. The protective film is preferably at least one of a cover film and a solder resist.

<Manufacturing method of photosensitive resin structure>

The method for forming the developable adhesive layer (a) and the developable protective layer (b) on the flexible printed wiring board may be a method using the dry film of the present invention, or a resin composition (a1) may be directly used. (B1) Coating method. The lamination method is a method in which a developable adhesive layer (a) is brought into contact with at least one of a bent portion and a non-bent portion of a flexible printed wiring board by a laminator or the like, and a dry film is bonded to the flexible portion. Printed wiring board.

The coating method is to apply a photosensitive or non-photosensitive resin composition (a1) and a photosensitive resin composition (b1) to a flexible printed wiring board in order by screen printing, etc., and dry to form The developability is followed by a layer (a) and a developability protective layer (b).

Alternatively, the resin composition (a1) may be coated on a flexible printed wiring board and dried to form a developable adhesive layer (a), and a thin film layer formed of the photosensitive resin composition (b1) may be used. A method for forming a developable protective layer (b) by combining the developable adhesive layer (a).

Alternatively, a thin film formed of the resin composition (a1) may be laminated on a flexible printed wiring board to form a developable adhesive layer (a), and the developable adhesive layer (a) may be formed on the flexible print wiring board. The photosensitive resin composition (b1) is applied and dried to form a developable protective layer (b).

〈Method for manufacturing flexible printed wiring board using negative photosensitive resin structure containing photopolymerization initiator〉

In the case of a negative-type laminated resin structure containing a photopolymerization initiator, at least one of the resin composition (a1) and the resin composition (b1) may contain 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 above-mentioned layer method. Then, in a contact or non-contact manner, The light-sensitive resin structure is irradiated with light in a pattern, and the unirradiated portion is developed to obtain a protective film with a negative pattern. Furthermore, when a composition containing a thermosetting component is used, it can be heat cured by heating to a temperature of about 140 to 180 ° C to form heat resistance, chemical resistance, moisture absorption resistance, adhesion, electrical characteristics, and the like. Protective film with excellent properties.

Since the negative photosensitive resin structure contains a photopolymerization initiator, the light-irradiated part is hardened by radical polymerization.

〈Production method of flexible printed wiring board using negative photosensitive resin structure containing photo-alkali generator〉

In the case of a negative laminated resin structure containing a photobase generator, it is only necessary that at least one of the resin composition (a1) and the resin composition (b1) contains a photobase generator. In this case, 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 above-mentioned lamination method. Subsequently, the negative-type photosensitive resin structure is irradiated with light in a pattern, and an alkali is generated from the photo-alkali generator to harden the light-irradiated portion. Subsequently, a non-irradiated portion was removed by development to obtain a protective film having a negative pattern. It is also preferable to heat the developable adhesive layer (a) and the developable protective layer (b) after light irradiation.

It is considered that a base is generated in the light-irradiated part by the light irradiation, and the base causes the photo-alkali generator to be unstable, thereby generating an alkali. By chemically accelerating the alkali in this manner, the light-irradiated portion is sufficiently hardened to a deep portion.

After development, in order to further improve the insulation reliability of the protective film, ultraviolet rays may be irradiated. In addition, after development, heat may be further included. In the curing (post-curing) step, ultraviolet irradiation and thermal curing may be performed simultaneously after development. The heating temperature in the heat curing step is, for example, 160 ° C or higher.

<Manufacturing method of flexible printed wiring board using negative photosensitive resin structure containing photoacid generator>

In the case of a negative laminated resin structure containing a photoacid generator, at least any one of the resin composition (a1) and the resin composition (b1) may include a photoacid generator. In this case, it is also the same as the case containing a photo-alkali generator. By using the above-mentioned layer method, a negative layer having a developable adhesive layer (a) and a developable protective layer (b) is formed on a flexible printed wiring board. Type photosensitive resin structure. Subsequently, the negative-type photosensitive resin structure is irradiated with light in a pattern, and an acid is generated from the photoacid generator to harden the light-irradiated portion. Subsequently, a protective film having a negative pattern was obtained by the same developing method as described above.

<Manufacturing method of flexible printed wiring board using positive photosensitive resin structure>

In the case of the positive-type laminated resin structure, at least one of the resin composition (a1) and the resin composition (b1) only needs to contain the positive-type composition. In this case, a positive photosensitive resin structure having a developable adhesive layer (a) and a developable protective layer (b) is also formed on the flexible printed wiring board using the above-mentioned layer method.

Next, the positive photosensitive resin structure is irradiated with light in a patterned shape to change the polarity. Subsequently, the light-irradiated portion was developed to obtain a positive type. Graphic protective film.

The exposure machine used for the above light irradiation may be a device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a short-arc mercury lamp, and the like, and irradiates ultraviolet rays in the range of 350 to 450 nm, and then Alternatively, a direct drawing device (such as a laser direct imaging device that draws an image with a direct laser through CAD data of a computer) may also be used.

If the laser light source of the direct drawing device uses laser light with a maximum wavelength in the range of 350 ~ 450nm, gas lasers and solid lasers can also be used. Although the amount of exposure used for image formation varies with film thickness, etc., it can generally be in the range of 20 to 1500 mJ / cm ² .

The aforementioned development method may be a dipping method, a rinsing method, a spray method, a brushing method, or the like, and the development solution may be potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, or amine. Class and other alkaline aqueous solutions.

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 is characterized by having a resin layer (A) composed of an alkali-developing resin composition, and a resin layer (a) laminated on a flexible printed wiring board via the resin layer (A) ( The laminated structure of B), wherein the resin layer (B) is a photosensitive thermosetting resin composition containing an alkali-soluble resin having a fluorene imine ring, a photo-alkali generator, and a heat-reactive compound.

Such a laminated structure according to 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 can be formed into a pattern at one time by development. .

According to the laminated structure of the present invention, by using (1) a resin having a fluorene imine ring in the molecule, and (2) a composition using an addition reaction of an alkali-soluble resin and a thermally reactive compound as a resin The layer (B) uses this layer as a reinforcing layer. Even if a conventional resin layer (A) made of a solder resist composition or an interlayer insulating material is used, it can still provide impact resistance, bendability, and low warpage. An insulating film for a flexible printed wiring board having excellent reliability and processing accuracy and excellent workability.

The laminated structure of the present invention has a resin layer (A) and a resin layer (B) in this order on a flexible printed wiring board on which a copper circuit is formed on a flexible substrate, and at least the resin layer can be irradiated by light. (B) Patterning, and the resin layer (A) and the resin layer (B) can be patterned at one time by imaging.

(Resin layer (A) constituting the laminated structure) (Alkali-developing resin composition constituting the resin layer (A))

The alkali-developing resin composition constituting the resin layer (A) may be a composition containing a resin containing one or more functional groups of a phenolic hydroxyl group, a thiol group, and a carboxyl group and capable of being developed by an alkali solution. A photocurable resin composition may be used, and a thermosetting resin composition may be used. Examples are compounds containing preferably a compound having two or more phenolic hydroxyl groups, a resin containing a carboxyl group, a compound having a phenolic hydroxyl group and a carboxyl group, and a compound having two or more thiol groups. The resin composition can be used by a conventional user.

Examples include photoresist containing carboxyl group-containing resins or carboxyl group-containing photosensitive resins, compounds having ethylenically unsaturated bonds, photopolymerization initiators, and thermoreactive compounds that have been used as solder resist compositions since the past. Thermosetting resin composition.

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, conventionally used ones can be used.

(Resin layer (B) constituting laminated structure) (Photosensitive thermosetting resin composition constituting the resin layer (B))

The photosensitive thermosetting resin composition constituting the resin layer (B) contains an alkali-soluble resin having a fluorene imine ring, a photo-alkali generator, and a heat-reactive compound.

(Alkali-soluble resin with fluorene imine ring)

In the present invention, the alkali-soluble resin having a fluorene imine ring is one having an alkali-soluble group such as a carboxyl group or an acid anhydride group and a fluorene imine ring. The alkali-soluble resin can be introduced into the fluorene imine ring by a conventional method. Examples thereof include resins obtained by reacting a carboxylic acid anhydride component with an amine component and / or an isocyanate component. The fluorene imidization can be carried out by hot fluoridation or by chemical fluoridation, and can be produced by using these in combination.

Here, the carboxylic acid anhydride component is exemplified by tetracarboxylic acid anhydride or tricarboxylic acid anhydride, but is not limited to those acid anhydrides. Compounds including acid anhydride groups and carboxyl groups that react with an acid ester group can be used including derivatives. These carboxylic anhydride components may be used alone or in combination.

Examples of tetracarboxylic anhydrides include pyromellitic dianhydride, 3-fluoro pyromellitic dianhydride, 3,6-difluoromellitic dianhydride, and 3,6-bis (trifluoromethyl) pyromellitic acid. Acid dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydihydride Phthalic 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 acid bis Anhydride, 5,5'-bis (trifluoromethyl) -3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 6,6'-bis (trifluoromethyl) -3,3' , 4,4'-biphenyltetracarboxylic dianhydride, 2,2 ', 5,5'-(trifluoromethyl) -3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2 ', 6,6'-Di (trifluoromethyl) -3,3', 4,4'-biphenyltetracarboxylic dianhydride, 5,5 ', 6,6'-di (trifluoro (Methyl) -3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, and 2,2', 5,5 ', 6,6'-Lu (trifluoromethyl) -3,3' , 4,4'-biphenyltetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3 , 3 ”, 4,4” -terephthalic dianhydride, 3,3 '”, 4,4'”-terephthalate dianhydride, 3,3 ””, 4,4 ””- Quinquephenyl tetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylene-4,4'-diphthalic dianhydride, 2,2-propylene-4,4'-diphthalic dianhydride, 1,2-ethylidene-4,4'-diphthalic dianhydride, 1,3-trimethylene- 4,4'-Diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic 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 '-Diphthalic dianhydride, 1,1,2,2- Tetrafluoro-1,2-ethenyl-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, sulfo-4,4'-diphthalic dianhydride, 1,3-bis (3,4-dicarboxyphenyl) -1,1,3 , 3-tetramethylsilyl dianhydride, 1,3-bis (3,4-dicarboxyphenyl) phthalic anhydride, 1,4-bis (3,4-dicarboxyphenyl) phthalic anhydride, 1,3-bis (3,4-dicarboxyphenoxy) phthalic anhydride, 1,4-bis (3,4-dicarboxyphenoxy) phthalic anhydride, 1,3-bis [2- (3 , 4-dicarboxyphenyl) -2-propyl] phthalic anhydride, 1,4-bis [2- (3,4-dicarboxyphenyl) -2-propyl] phthalic anhydride, 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-carboxyphenoxy) 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-tetramethyldisilazane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10- Perylene tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 1,2,7,8-phenanthrene tetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic acid Dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane -1,2,4,5-tetracarboxylic dianhydride, 3,3 ', 4,4'-bicyclohexanetetracarboxylic dianhydride, carbonyl-4,4'-bis (cyclohexane-1, 2-dicarboxylic acid) dianhydride, methylene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylidene- 4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) diamine Anhydride, 2,2-propylene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1,1,3,3,3-hexafluoro-2,2 -Propylene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) diamine Anhydride, thio-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfofluorenyl-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) Dianhydride, 3,3'-difluoroxy-4,4'-diphthalic acid dianhydride, 5,5'-difluorooxy-4,4'-diphthalic acid di Anhydride, 6,6'-difluorooxy-4,4'-diphthalic dianhydride, 3,3 ', 5,5', 6,6'-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 '-Di (trifluoromethyl) oxy-4,4'-diphthalic dianhydride, 3,3', 6,6'-Di (trifluoromethyl) oxy-4,4'- Diphthalic dianhydride, 5,5 ', 6,6'-three (trifluoro (Oxy) oxy-4,4'-diphthalic dianhydride, 3,3 ', 5,5', 6,6'-Hydroxy (trifluoromethyl) oxy-4,4'-di-ortho Phthalic acid dianhydride, 3,3'-difluorosulfonyl-4,4'-diphthalic acid dianhydride, 5,5'-difluorosulfonyl-4,4'-diphthalic acid Formic acid dianhydride, 6,6'-difluorosulfonyl-4,4'-diphthalic dianhydride, 3,3 ', 5,5', 6,6'-hexafluorosulfonyl-4 , 4'-Diphthalic dianhydride, 3,3'-bis (trifluoromethyl) sulfofluorenyl-4,4'-diphthalic dianhydride, 5,5'-bis (trifluoro (Methyl) sulfofluorenyl-4,4'-diphthalic dianhydride, 6,6'-bis (trifluoromethyl) sulfofluorenyl-4,4'-diphthalic dianhydride, 3 , 3 ', 5,5'-Di (trifluoromethyl) sulfofluorenyl-4,4'-diphthalic dianhydride, 3,3', 6,6'-di (trifluoromethyl) Sulfo-4,4'-diphthalate Formic acid dianhydride, 5,5 ', 6,6'-(trifluoromethyl) sulfofluorenyl-4,4'-diphthalic dianhydride, 3,3 ', 5,5', 6, 6'-Lu (trifluoromethyl) sulfofluorenyl-4,4'-diphthalic dianhydride, 3,3'-difluoro-2,2-perfluoropropylene-4,4'- Diphthalic acid dianhydride, 5,5'-difluoro-2,2-perfluoropropylene-4,4'-diphthalic acid dianhydride, 6,6'-difluoro-2,2 -Perfluoropropylene-4,4'-diphthalic dianhydride, 3,3 ', 5,5', 6,6'-hexafluoro-2,2-perfluoropropylene-4, 4'-diphthalic acid dianhydride, 3,3'-bis (trifluoromethyl) -2,2-perfluoropropylene group-4,4'-diphthalic acid dianhydride, 5,5 '-Bis (trifluoromethyl) -2,2-perfluoropropylene-4,4'-diphthalic dianhydride, 6,6'-difluoro-2,2-perfluoropropylene -4,4'-Diphthalic dianhydride, 3,3 ', 5,5'-Di (trifluoromethyl) -2,2-perfluoropropylene-4,4'-diphthalic acid Dicarboxylic dianhydride, 3,3 ', 6,6'-Di (trifluoromethyl) -2,2-perfluoropropylene-4,4'-diphthalic dianhydride, 5,5' , 6,6'-Di (trifluoromethyl) -2,2-perfluoropropylene-4,4'-diphthalic dianhydride, 3,3 ', 5,5', 6,6 '-Lu (trifluoromethyl) -2,2-perfluoropropylene -4,4'-diphthalic dianhydride, 9-phenyl-9- (trifluoromethyl) xanthene-2,3,6,7-tetracarboxylic dianhydride, 9,9-bis ( Trifluoromethyl) xanthene-2,3,6,7-tetracarboxylic dianhydride, bicyclic [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 9,9-bis [4- (3,4-dicarboxy) phenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxy) phenyl] fluorenic dianhydride, ethylene glycol bis Trimellitic dianhydride, 1,2- (triethyl) bis (trimellitic anhydride), 1,3- (trimethylene) bis (trimellitic anhydride), 1,4- (tetramethylene) bis (trimellitic anhydride), 1,5- (pentamethylene) bis (trimellitic anhydride), 1,6- (hexamethylene) bis (trimellitic anhydride), 1,7- (heptamethylene) bis (trimellitic anhydride), 1,8- ( Octamethylene) bis (trimellitic anhydride), 1,9- (ninemethylene) bis (trimellitic acid) (Anhydride), 1,10- (decylmethylene) bis (trimellitic anhydride), 1,12- (dodecylmethylene) bis (trimellitic anhydride), 1,16- (hexamethylene) bis (trimellitic anhydride) 1,18- (octadecylene) bis (trimellitic anhydride) and the like.

Examples of the tricarboxylic anhydride include trimellitic anhydride, nuclear hydrogenated trimellitic anhydride, and the like.

The amine component may be a diamine such as an aliphatic diamine or an aromatic diamine, or a polyamine such as an aliphatic polyetheramine, but is not limited to these amines. Moreover, these amine components can be used individually or in combination.

Examples of diamines include p-phenylenediamine (PPD), 1,3-diaminobenzene, 2,4-toluenediamine, 2,5-toluenediamine, 2,6-toluenediamine, 3,5 -Diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,4-diaminobenzoic acid, etc., one benzene core diamine, 4,4'-diaminodiphenyl ether, 3 , 3'-diaminodiphenyl ethers, 3,4'-diaminodiphenyl ethers and other diamine diphenyl ethers, 4,4'-diaminodiphenylmethane, 3, 3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diamine Diphenylmethane, 3,3 ', 5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis (4-aminophenyl) sulfide, 4,4'-di Aminobenzidine, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (o-toluidine), 2,2'-dimethylbenzidine (m-toluidine) , 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'-diaminodiphenylphosphonium, 3,4'-diaminodiphenylphosphonium, 4,4'-diaminodiphenylphosphonium, 3,3'-diamino Benzophenone, 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'-diaminodiphenylsulfene, 3,4'-diamine Diphenylphosphonium, 4,4'-diaminodiphenylphosphonium, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 2,2-bis (3-amine 2-hydroxyphenyl) hexafluoropropane, 3,3'-diamino-4,4'-dihydroxydiphenylsulfonium, etc. 2 benzene diamines, 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-amino (Oxy) -4-trifluoromethylbenzene, 3,3'-diamino-4- (4-phenyl) phenoxybenzophenone, 3,3'-diamino-4,4 ' -Bis (4-phenylphenoxy) benzophenone, 1,3-bis (3-aminophenylsulfide) benzene, 1,3-bis (4-aminophenylsulfide) benzene, 1,4-bis (4-aminophenylsulfide) benzene, 1,3-bis (3-aminophenylphosphonium) benzene, 1,3-bis (4-aminophenylphosphonium) benzene, 1 1,4-bis (4-aminophenylphosphonium) benzene, 1,3-bis [2- (4-aminophenyl) isopropyl] benzene, 1,4-bis [2- (3-amino Phenyl) isopropyl] benzene, 1,4-bis [2- (4-aminophenyl) isopropyl] benzene, 1,3-bis (4-amino-3-hydroxyphenoxy) benzene 3 benzene diamines, 3,3'-bis (3-aminophenoxy) biphenyl, 3,3'-bis (4-aminophenoxy) biphenyl, 4,4 ' -double (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] one, bis [3- (4-aminophenoxy) phenyl] one, bis [4- (3-aminophenoxy) ) Phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] one, 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] fluorene, bis [3- (4-aminophenoxy) phenyl] fluorene, bis [4- (3-aminophenoxy) benzene Yl] fluorene, bis [4- (4-aminophenoxy) phenyl] fluorene, bis [3- (3-aminophenoxy) phenyl] methane, bis [3- (4-aminophenylbenzene Oxy) 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-amine Phenylphenoxy) phenyl] propane, 2,2-bis [4- (4- Phenylphenoxy) 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, Aromatic diamines such as 4 benzene diamines such as 3,3-hexafluoropropane, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane , 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane , 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,2- Examples of the aliphatic diamines such as diaminocyclohexane, and the aliphatic polyetheramines include ethylene glycol and / or propylene glycol-based polyamines.

As the isocyanate component, diisocyanates such as aromatic diisocyanate and its isomers or polymers, aliphatic diisocyanates, alicyclic diisocyanates and its isomers, or other widely used diisocyanates may be used. Limited to these diisocyanates. These isocyanate components can be used alone or in combination.

Examples of the diisocyanate include 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, naphthalene diisocyanate, xylene diisocyanate, biphenyl diisocyanate, diphenylphosphonium diisocyanate, diphenyl ether diisocyanate, and the like Aromatic diisocyanates and their isomers, polymers, hexamethylene diisocyanates, isophorone diisocyanates, dicyclohexylmethane diisocyanates, xylene diisocyanates, and the like, or the aforementioned aromatic diisocyanates Group diisocyanates are hydrogenated alicyclic diisocyanates and isomers, or other widely used diisocyanates.

The alkali-soluble resin having a fluorene imine ring as described above may have a fluorene bond. These may be amide bonds obtained by the reaction of isocyanate and carboxylic acid, or may be obtained by other reactions. Furthermore, it may have bonds formed by other additions and condensations.

In addition, the alkali-soluble resin having a fluorene imine ring introduced into the alkali-soluble resin may be a conventionally-used alkali-soluble polymer, oligomer, or monomer having a carboxyl group and / or an acid anhydride, or may be, for example, a conventionally-used alkali A resin obtained by dissolving a soluble resin alone or in combination with the carboxylic anhydride component and reacting with the amine / isocyanate.

For the synthesis of the alkali-soluble resin having an alkali-soluble group and an imine ring, a conventional organic solvent can be used. As long as the organic solvent does not react with carboxylic acid anhydrides, amines, and isocyanates of the raw materials, and the solvent can dissolve these raw materials, there is no problem, especially its structure is not limited. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, and other amine solvents such as γ-butyrolactone and γ-valerolide. Cyclic ester solvents such as esters, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, carbonate solvents such as ethyl carbonate and propylene carbonate, Lactamine solvents such as caprolactam, ether solvents such as dioxane, glycol solvents such as triethylene glycol, m-cresol, p-cresol, 3-chlorophenol, 4-chlorophenol, 4- Phenolic solvents such as methoxyphenol and 2,6-dimethylphenol, acetophenone, 1,3-dimethyl-2-imidazolidone, cyclobutane, dimethylsulfenyl, and tetramethylurea Wait. In addition, other general organic solvents can also be added, that is, phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl fusin, butyl cellosolve, 2-methyl lysin acetate, ethyl lysin acetate, butyl lysin acetate, tetrahydrofuran, dimethoxyethane, diethoxyethane, dibutyl ether, diethyl Glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpenes, mineral oil It is used as a solvent for petroleum spirit and petroleum brain. Among them, aprotic solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfine, and γ-butyrolactone It is preferable because the solubility of the raw material is high.

The alkali-soluble resin having a base-soluble group such as a carboxyl group or an acid anhydride group, or an alkali-imide ring as described above corresponds to the photolithography step, The acid value is preferably 20 to 200 mgKOH / g, and more preferably 60 to 150 mgKOH / g. When the acid value is 20 mgKOH / g or more, the solubility to alkali is increased, and the developability is improved. Furthermore, since the degree of cross-linking with the thermosetting component after light irradiation is high, sufficient contrast for development can be obtained. In addition, when the acid value is 200 mgKOH / g or less, the so-called heat load in the PEB (POST EXPOSURE BAKE) step after light irradiation described later can be suppressed, and the process margin can be increased.

In addition, when the molecular weight of the alkali-soluble resin is in consideration of the developability and the characteristics of the cured coating film, the mass average molecular weight is preferably 1,000 to 100,000, and more preferably 2,000 to 50,000.

When the molecular weight is 1,000 or more, sufficient development resistance can be obtained after ‧PEB exposure. In addition, when the molecular weight is 100,000 or less, alkali solubility increases and developability improves.

(Photo-alkali generator)

The photo-alkali generator used in the resin layer (B) changes the molecular structure by irradiation with light such as ultraviolet rays or visible light, or polymerizes one or more types of thermally reactive compounds to be described later by molecular chain breaking. A compound of a basic substance that functions as a reaction catalyst. Examples of the basic substance include a secondary amine and a tertiary amine.

Examples of the photobase generator include an α-aminoacetophenone compound, an oxime ester compound, or an alkoxyimine group, an N-formamated aromatic amine group, an N-fluorinated aromatic amine group, Compounds having substituents such as a nitrobenzylcarbamate group and an alkoxybenzylcarbamate group. Oxime ester And α-aminoacetophenone compounds are preferred. As for the α-aminoacetophenone compound, those having two or more nitrogen atoms are preferred.

Other photobase generators can also use WPBG-018 (trade name: N, N'-diethylaminoformic acid 9-anthryl methyl ester), WPBG-027 (trade name: (E) -1- [3- (2-hydroxyphenyl) -2-propenyl) piperidine), WPBG-082 (trade name: 2- (3-benzylidenephenyl) propionate guanidinium salt), WPBG-140 (commercial product Name: 1- (1- (anthraquinone-2-yl) ethyl) imidazolecarboxylic acid) and the like.

The α-aminoacetophenone compound has a benzoin ether bond in the molecule and causes chain breakage in the molecule when exposed to light, thereby generating an alkaline substance (amine) that functions as a hardening catalyst. As a specific example of the α-aminoacetophenone compound, (4-morpholinylbenzyl) -1-benzyl-1-dimethylaminopropane (IRGACURE 369, trade name, manufactured by BASF, Japan) or 4- (methylthiobenzyl) -1-methyl-1-morpholinoethane (IRGACURE 907, trade name, manufactured by BASF Japan), 2- (dimethylamino) -2- [(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (IRGACURE 379, trade name, made by Japan BASF Corporation), etc. A commercially available compound or a solution thereof.

Any oxime ester compound can be used as long as it is a compound that generates a basic substance by light irradiation. The commercially available oxime ester compounds are CGI-325, IRGACURE-OXE01, IRGACURE-OXE02, and N-1919, NCI-831, manufactured by ADEKA (stock). In addition, a compound having two oxime ester groups in a molecule described in Japanese Patent No. 4344400 can also be used.

In addition, Japanese Patent Application Laid-Open No. 2004-359639, Japanese Patent Application Laid-Open No. 2005-097141, Japanese Patent Application Laid-Open No. 2005-220097, Japanese Patent Application Laid-Open No. 2006-160634, Japanese Patent Application Laid-Open No. 2008-094770, The carbazoxime ester compounds described in Japanese Patent Application Publication No. 2008-509967, Japanese Patent Application Publication No. 2009-040762, and Japanese Patent Application Publication No. 2011-80036.

This photobase generator may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the photobase generator in the thermosetting resin composition is preferably 0.1 to 40 parts by mass, more preferably 0.1 to 30 parts by mass, relative to 100 parts by mass of the thermally reactive compound. When it is 0.1 parts by mass or more, good contrast of development resistance of the light-irradiated portion / non-irradiated portion can be obtained. Moreover, when it is 40 mass parts or less, hardening characteristics will improve.

(Thermally reactive compound)

The thermally reactive compound used in the resin layer (B) is a resin having a functional group capable of undergoing a hardening reaction by heat, preferably a resin having a cyclic (thio) ether group, and more preferably an epoxy resin or a polyfunctional resin. Oxetane compounds and the like. 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 one of the conventional ones can be used. Examples thereof include a bifunctional epoxy resin having two epoxy groups in a molecule, a polyfunctional epoxy resin having a plurality of epoxy groups in a molecule, and the like. It may also be a hydrogenated bifunctional epoxy compound.

Polyfunctional epoxy compounds are listed as bisphenol A epoxy trees Grease, brominated epoxy resin, novolac epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, glycidylamine epoxy resin, hydantoin epoxy resin Resin, alicyclic epoxy resin, trihydroxyphenylmethane type epoxy resin, bisxylenol type or biphenol type epoxy resin or a mixture of these lipids; bisphenol S type epoxy resin, bisphenol A novolac Type epoxy resin, tetrahydroxyphenylethane type epoxy resin, heterocyclic epoxy resin, diglycidyl phthalate resin, tetraglycidyl xylyl fluorenyl ethane resin, naphthyl group-containing Epoxy resin, epoxy resin with dicyclopentadiene skeleton, glycidyl methacrylate copolymer epoxy resin, cyclohexyl maleimide and glycidyl methacrylate copolymer epoxy resin , CTBN modified epoxy resin, etc.

Other liquid bifunctional epoxy resins include vinyl cyclohexene diepoxide, (3 ', 4'-epoxycyclohexylmethyl) -3,4-epoxycyclohexanecarboxylic acid. Aliphatic epoxy resins such as esters, (3 ', 4'-epoxy-6'-methylcyclohexylmethyl) -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 and bis [(3-ethyl-3-oxetanylmethoxy) Methyl] ether, 1,4-bis [(3-methyl-3-oxetanylmethoxy) methyl] benzene, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) (Meth) methyl] benzene, (3-methyl-3-oxetanyl) methyl acrylate, (3-ethyl-3-oxetanyl) methyl acrylate, (3-methyl methacrylate) Multifunctional oxetanyl, such as methyl-3-oxetanyl) methyl ester, (3-ethyl-3-oxetanyl) methacrylate, or oligomers or copolymers thereof alkyl With oxetanol and novolac resins, poly (p-hydroxystyrene), cardo type bisphenols, calixarenes, resorcinol calixarene Type, or ethers of resins having a hydroxyl group, such as sesquioxane. In addition, a copolymer of an unsaturated monomer having an oxetane ring and an alkyl (meth) acrylate is also cited.

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

(Polymer resin)

In the resin composition used in the resin layer (A) and the resin layer (B) described above, a conventional polymer resin may be blended in order to improve the flexibility and touch-dryness of the obtained cured product. The polymer resin is exemplified by cellulose-based, polyester-based, phenoxy resin-based polymers, polyethylene acetal-based, polyvinyl butyral-based, polyamido-based, polyamido-imide-based binder polymerization Materials, block copolymers, elastomers, etc.

This polymer resin may be used singly or in combination of two or more kinds.

(Inorganic filler)

In addition, in the resin composition used in the resin layer (A) and the resin layer (B), in order to suppress the hardening shrinkage of the cured material, and to improve the adhesion and hardness, etc. Characteristics, and can be adjusted with inorganic fillers. Examples of the inorganic filler include barium sulfate, amorphous silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, and nitride. Aluminum, boron nitride, Neuburg siliceous earth, etc.

(Colorant)

Furthermore, a conventionally-used coloring agent may be blended in the resin composition used in the resin layer (A) and the resin layer (B).

In the past, the edge of the copper circuit in the printed wiring board may have insufficient coloring power of the pattern layer. In the thermal history after the pattern layer is formed, the copper will discolor, and only the thin part of the appearance will be discolored. Typical thermal experiences are thermal curing of tags, warping and straightening, pre-heating before installation, installation, and the like.

Therefore, in the past, more coloring agents were deployed in the pattern layer to improve the tinting power, thereby eliminating the problem of discoloration seen only at the edge portion of the copper circuit.

However, since the colorant is light-absorbing, it prevents light from being transmitted to the deep part. As a result, a composition containing a colorant is liable to undercut, and it is difficult to obtain sufficient adhesion.

In contrast, the resin composition used in the present invention can be sufficiently hardened to the deep portion of the resin layer by chemically accelerating alkali to the deep portion.

Therefore, according to the resin composition used in the present invention, when a colorant is contained, a pattern layer having excellent concealability and excellent adhesion of a copper circuit can be formed.

(Organic solvents)

Among the resin compositions used in the resin layer (A) and the resin layer (B), an organic solvent may be used in order to adjust the resin composition or to adjust the viscosity for coating on a substrate or a carrier film.

Examples of the organic solvent include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum-based solvents. This organic solvent may be used individually by 1 type, and may be used in mixture of 2 or more type.

(Other optional ingredients)

In the resin composition used in the resin layer (A) and the resin layer (B), components such as a thiol compound, an adhesion promoter, an antioxidant, and an ultraviolet absorber may be further blended as necessary. These are known to those skilled in the art of electronic materials. In addition, conventionally used thickeners such as micronized silicon dioxide, hydrotalcite, organic bentonite, and montmorillonite can be blended, such as defoamers and / or leveling agents such as silicone, fluorine, and polymer, and silane Coupling agents, rust inhibitors, and the like are commonly used additives.

Next, the embodiment of the manufacturing method of the flexible printed wiring board of this invention is demonstrated in detail. The method for manufacturing a flexible printed wiring board of the present invention is characterized by including the following steps: forming at least one resin layer (A) composed of an alkali-developing photosensitive resin composition (A1) on the flexible printed wiring board. Step), forming at least one layer of a photosensitive thermosetting resin composition comprising an alkali-soluble resin having a fluorene imine ring, a photo-alkali generator, and a heat-reactive compound on the resin layer (A). (B1) A step of forming the resin layer (B), a step of irradiating light into a pattern on the resin layers (A) and (B) formed in the foregoing step, and heating the light-irradiated portion in the foregoing step. The steps of the resin layers (A) and (B), and the step of alkali developing the aforementioned light-irradiated resin layers (A) and (B) to form at least one of a cover film and a solder resist.

In the present invention, in the resin layer (B), by using (1) a resin having a fluorene imine ring in the molecule, and (2) using a composition that causes an addition reaction between an alkali-soluble resin and a heat-reactive compound, The resin layer (B) can function as a reinforcing layer.

That is, by forming a resin layer (A) composed of a conventional solder resist composition, and laminating the resin layer (B) on the resin layer (A), it can be formed at one time on a flexible printed wiring board. Cover film and solder resist with excellent reliability and processing accuracy, such as impact resistance, bendability, and low warpage. Alternatively, an interlayer insulating film may be formed as the insulating film.

Hereinafter, an example of a method for manufacturing a flexible printed wiring board of the present invention will be described based on FIG. 3.

[Formation step of resin layer (A)]

This step is to form at least one resin layer (A) composed of an alkali-developing photosensitive resin composition (A1) on a flexible printed wiring board. The resin layer (A) can be patterned due to alkali development. And by laminating the resin layer (A), it is possible to improve circuit followability and adhesion to the substrate.

The flexible printed wiring board is formed by forming a copper circuit 2 on a flexible substrate 1. The position where the resin layer (A) is formed is any of a curved portion and a non-curved portion. Either one can be used, but both curved and non-curved portions are preferred. The so-called bent portion is a portion that can be repeatedly bent and requires bendability, and the non-bent portion is an unbent portion such as a wafer mounting portion.

The method for forming the resin layer (A) includes a coating method and a layer method.

In the case of the coating method, an alkali-developing photosensitive resin composition (A1) is applied to a flexible printed wiring board by methods such as screen printing, curtain coating, spray coating, and roll coating. Then, the resin layer (A) is formed by heating at a temperature of about 50 to 130 ° C for about 15 to 60 minutes.

In the case of lamination, first, the alkali-developing photosensitive resin composition (A1) is diluted with an organic solvent to adjust the viscosity to the appropriate viscosity, and then coated on a carrier film, and dried to form a dry film having a resin layer (A). Next, after laminating | bonding by a laminator etc. so that a resin layer (A) may contact a flexible printed wiring board, a carrier is peeled.

[Formation step of resin layer (B)]

This step is to form at least one layer of a photosensitive thermosetting resin composition (B1) containing an alkali-soluble resin having a fluorene imine ring, a photobase generator, and a thermoreactive compound on the resin layer (A). Resin layer (B). Since the resin layer (B) can be developed by alkali, fine patterns can be formed and the processing accuracy is excellent. In addition, by laminating the resin layer (B), impact resistance, bendability, and low warpage can be improved.

The position where the resin layer (B) is formed is preferably both the curved portion and the non-curved portion on the resin layer (A). However, it is also possible to bend the resin layer (A) only The resin layer (B) is formed in a curved portion or only in a non-curved portion.

In addition, another 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 of forming the resin layer (A).

Further, the resin layers (A) and (B) may be formed into a laminated dry film, and then the laminated dry film is laminated on a flexible printed wiring board.

In the present invention, the resin layer (A) is preferably formed to be thicker than the resin layer (B) from the viewpoint of followability to a copper circuit.

[Light irradiation step]

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, and the light-irradiated part can be hardened. By generating alkali in this way, it chemically accumulates to the deep part of the resin layer, and it is considered that it can be sufficiently hardened to the deep part of the resin layer. During subsequent thermal hardening, the base functions as a catalyst for the addition reaction between the alkali-developing resin and the heat-reactive compound on the one hand, and performs the addition reaction on the other hand, so the resin layer in the light-irradiated part can be sufficiently hardened to Deep. In this way, the hardening of the curable resin composition of the present invention is, for example, a ring-opening reaction using an epoxy group that is thermally reacted, so that deformation or hardening shrinkage can be suppressed compared to when the light reaction proceeds.

As for the light irradiation machine, a direct drawing device can be used (e.g., a laser direct drawing device that directly draws an image by laser using CAD data of a computer), A direct drawing device equipped with a light irradiating machine equipped with a metal halide lamp, a light irradiating machine equipped with an (ultra-high pressure) mercury lamp, a light irradiating machine equipped with a short arc mercury lamp, or an ultraviolet lamp using a (ultra-high pressure) mercury lamp.

The active energy ray used for light irradiation preferably uses laser light or scattered light having a maximum wavelength in the range of 350 to 450 nm. In addition, although the amount of light irradiation varies depending on the film thickness and the like, it may be generally within a range of 50 to 1500 mJ / cm ² , and preferably within a range of 100 to 1000 mJ / cm ² .

[Heating step]

In this step, the resin layers (A) and (B) are heated. Thereby, the alkali generated by light irradiation can be sufficiently hardened to a deep part. This step is a step called a so-called PEB (post-exposure baking) step.

The heating temperature is preferably a temperature at which the light-irradiated portion in the thermosetting resin composition is thermally cured, but the non-irradiated portion is not thermally cured.

For example, the heating step is preferably lower than the heat generation onset temperature or peak heating temperature of the non-irradiated thermosetting resin composition and higher than the heat generation onset temperature or peak heating temperature of the light-cured thermosetting resin composition. Heating at temperature. By heating in this way, only the light irradiation part can be selectively hardened.

The heating temperature is, for example, 80 to 140 ° C. By setting the heating temperature to 80 ° C or higher, the light-irradiated portion can be sufficiently hardened. On the other hand, by setting the heating temperature to 140 ° C. or lower, it is possible to selectively harden only the light irradiation portion. The heating time is, for example, 10 to 100 minutes. Moreover, since the non-irradiated part does not generate an alkali from a photobase generator, thermal hardening is suppressed.

[Development steps]

In this step, the resin layers (A) and (B) irradiated with light are developed to form at least one of a cover film and a solder resist. With this development, a pattern-like cover film and solder resist can be obtained at one time.

The imaging method is alkaline imaging, and a known method such as a dipping method, a rinsing method, a spray method, or a brushing method can be used.

As the alkali developing solution, amines such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, ethanolamine, imidazole, and tetramethylammonium hydroxide aqueous solution (TMAH) can be used. Or a mixture of these.

[Other steps]

The present invention can also add the following steps as needed.

(Second light irradiation step)

After the developing step, the resin layers (A) and (B) may also be irradiated with light. By this light irradiation, the photo-alkali generator remaining in the resin layer (B) which has not been activated in the previous light irradiation step is activated to sufficiently generate alkali.

The wavelength and light irradiation amount (exposure amount) of the ultraviolet rays in the light irradiation may be the same as or different from the aforementioned light irradiation step. The light irradiation amount is, for example, 150 to 2000 mJ / cm ² .

(Thermal hardening step)

Further, after the developing step, the resin layers (A) and (B) may be further thermally cured (post-cured) by heating. This thermal curing step is to sufficiently thermally harden the pattern layer by using an alkali generated from the photo-alkali generator in the light irradiation step, the light irradiation step, and the second light irradiation step. At the time of the thermal curing step, since the unirradiated portion has been removed, the thermal curing step can be performed at a temperature higher than the curing reaction start temperature of the unirradiated thermosetting resin composition. By thermal curing, the resin layers (A) and (B) can be sufficiently thermally cured. The heating temperature is, for example, 150 ° C or higher.

Examples

Examples and comparative examples are given below to specifically describe the present invention, but the present invention is not limited to the following examples.

(Examples 1, 2, Comparative Examples 1, 2)

Various components shown in Table 1 were prepared in the proportions (parts by mass) shown in Table 1 below, pre-mixed with a blender, and kneaded with a 3-axis roller kneader to prepare a photosensitive resin composition.

(Example 1)

Regarding the first embodiment, the use layer is legal. In Example 1, the photosensitive resin composition for layer (b) was coated on a carrier film and dried to form After the developable protective layer, the photosensitive resin composition for the layer (a) is coated on the surface and dried to obtain a dry film. This dry film was pressed onto a flexible printed wiring board at 120 ° C to form a photosensitive resin structure. The film thickness is shown in Table 1.

(Example 2)

About Example 2, the photosensitive resin composition for the layer (a) was coated on a flexible printed wiring board using a full-printing method, and dried, and then the photosensitive resin composition for (b) was coated on the surface. And dried to form a photosensitive resin structure. The film thickness is shown in Table 1.

(Comparative example 1)

In Comparative Example 1, a full-print method was used, and the photosensitive resin composition for layer (b) was applied to a flexible printed wiring board and dried to obtain a flexible printed wiring board having only (b) layers. The film thickness is shown in Table 1.

(Comparative example 2)

In Comparative Example 2, a full-print method was used, and the photosensitive resin composition for the (a) layer was applied to a flexible printed wiring board and dried to obtain a flexible printed wiring board having only the (a) layer. The film thickness is shown in Table 1.

(Comparative example 3)

The comparative example 3 is a layer-based method. Comparative Example 3 was applied on a polyimide film having an opening pattern of 5 mm × 5 mm by press processing. (a) The resin for the layer is dried and then pressed onto a flexible printed wiring board at 120 ° C. Thereby, a flexible printed wiring board having a pattern is obtained. The film thickness is shown in Table 1.

(Comparative Example 4)

Comparative Example 4 used a pattern printing method to print a pattern of 5 mm × 5 mm on a polyimide film and apply a resin for layer (b) and dried to obtain a pattern having only (b) layer. Flexible printed wiring board. The film thickness is shown in Table 1.

<Alkali imaging test>

For the photosensitive resin structures of Examples 1 and 2 and Comparative Examples 1 and 2, an exposure device (HMW-680-GW20) equipped with a metal halide lamp was used to irradiate light through a negative mask at an exposure of 500 mJ / cm ² And imaging was performed (30 ° C, 0.2 MPa, 1% by mass sodium carbonate aqueous solution), and it was investigated whether alkali imaging was possible.

<Flexibility test>

With respect to the photosensitive structures of Examples 1 and 2 and the resin layers of Comparative Examples 1 and 2, the pattern of openings (5 x 5 mm) was formed by light irradiation and development in the same manner as the alkali developability test described above. .

The flexible printed wiring boards having the patterns of Examples 1, 2 and Comparative Examples 1 to 4 were bent by 180 °. When no rupture occurred, it was recorded as good, and when rupture occurred, it was recorded as bad.

<Electrical Characteristics Test>

On a flexible printed wiring board with comb electrodes (line / space = 100 μm / 100 μm), as in the alkali developability test described above, Examples 1, 2 and Comparative Examples were formed by light irradiation and development. Patterns 1 to 4 were used to produce evaluation boards. The evaluation substrate was placed in a high-temperature and high-humidity tank under an environment of 130 ° C. and 85% humidity, and was charged at a voltage of 50 V to perform a HAST test in the tank for 1,000 hours. Those who were not short-circuited were regarded as good, and those who were short-circuited were regarded as bad.

<Opening Exudation Test>

As for the photosensitive resin structures of Examples 1 and 2 and the resin layers of Comparative Examples 1 and 2, similar to the alkali developability test described above, a figure with openings (5 x 5 mm) was formed by light irradiation and development. type.

For the patterns of Examples 1, 2 and Comparative Examples 1 to 4, the presence or absence of bleeding to the inside of the opening (5 × 5 mm) was evaluated. The results of the aforementioned evaluation tests are shown in Table 2.

As can be seen from the results shown in Table 2 above, Examples 1 and 2 The photosensitive resin structure can be developed on a flexible printed wiring board to form a fine pattern. In addition, it can be seen that the protective films of Examples 1 and 2 are excellent in flexibility and electrical insulation.

On the other hand, the protective film of Comparative Example 1 cannot obtain flexibility, and the protective film of Comparative Example 2 has insufficient insulation properties. On the other hand, the protective films of Comparative Examples 3 and 4 both bleed to the openings on the flexible printed wiring board, and it was found that it was not suitable for forming a fine pattern.

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

(Examples 3, 4 and Comparative Example 5) Synthesis Example: <Synthesis of Resin Containing Amines and Carboxyl Groups>

Add 12.2 g of 3,5-diaminobenzoic acid and 8.2 g of 2,2'-bis [4- (4-amine) to a separable 3-necked flask equipped with a stirrer, nitrogen introduction tube, fractionation ring, and cooling ring. Phenylphenoxy) phenyl] propane, 30g NMP, 30g γ-butyrolactone, 27.9g of 4,4'-oxydiphthalic anhydride, 3.8g of trimellitic anhydride, at room temperature in a nitrogen atmosphere Stir at 100 rpm for 4 hours. Next, 20 g of toluene was added, and the toluene and water were stirred at a silicone oil bath temperature of 180 ° C and 150 rpm for 4 hours to obtain a polyimide solution.

<Preparation of resin composition constituting each resin layer>

According to the formulations described in Table 3 below, the materials described in the Examples and Comparative Examples were prepared, pre-mixed with a blender, and kneaded with a 3-axis kneader to prepare the resin composition constituting each resin. The values in the table Ming is the mass part.

<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 using Merck CZ-8100 for pretreatment. Subsequently, according to the coating methods shown in Table 3, the flexible printed wiring substrates subjected to the pretreatment were subjected to the methods of Examples 3, 4 and Comparative Example 5 so that the film thickness after drying was 25 μm. Coating of resin composition. Subsequently, drying was performed at 90 ° C./30 minutes in a hot-air circulation drying furnace to form a resin layer (A) composed of a resin composition.

<Formation of Resin Layer (B)>

On the resin layer (A) formed as described above, the resin composition of Examples 3 and 4 was coated by the coating method shown in Table 3 so that it became 10 μm after drying. Subsequently, drying was performed in a hot-air circulation type drying furnace at 90 ° C. for 30 minutes to form a resin layer (B) composed of a resin composition. In addition, in Comparative Example 1, formation of the resin layer (B) was not performed.

`` Evaluation of image development (patterning) and hardening characteristics ''

In Examples 3 and 4, the flexible printed wiring boards having the resin layers (A) and (B) obtained as described above were exposed as shown in Table 3 by using HMW680GW (metal halide lamp, scattered light) from ORC. The amount is irradiated with light in a negative pattern. Then, it heat-processed at 90 degreeC for 60 minutes. Subsequently, the substrate was immersed in 1% by mass of carbon at 30 ° C. The development was performed in an aqueous sodium solution for 3 minutes to evaluate whether or not there was developability. In Comparative Example 5, the flexible printed wiring board provided with the resin layer (A) obtained as described above was evaluated in the same manner as in Example 3 to determine whether or not there was developability. The results obtained are shown in Table 3.

Next, a hot air circulation type drying furnace was used to perform a heat treatment at 150 ° C / 60 minutes to obtain a patterned hardened coating film. The obtained cured coating film was subjected to a MIT test (using a base material of UPILEX 12.5 μm manufactured by Ube Kosan Co., Ltd.) and a surface hardness test (pencil hardness test) to evaluate bendability and surface hardness. The results obtained are shown in Table 3 below.

As can be understood 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 have excellent flexibility and surface hardness. .

1‧‧‧ photosensitive resin structure

2‧‧‧ flexible substrate

3‧‧‧copper circuit

a‧‧‧Imaging layer

b‧‧‧ Imaging protective layer

Claims (15)

A photosensitive resin structure comprising a developable adhesive layer (a) and a developable protective layer (b) laminated on a flexible printed wiring board via the developable adhesive layer (a). ; 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) can be developed by imaging Those who form the pattern at one time; wherein the aforementioned developable adhesive layer (a) is thicker than the aforementioned developable protective layer (b) and does not contain polyamic acid. The photosensitive resin structure according to claim 1, wherein the imageable adhesive layer (a) and the imageable protective layer (b) can be patterned together by light irradiation. The photosensitive resin structure according to claim 1, which is used in at least one of a curved portion and a non-curved portion of a flexible printed wiring board. The photosensitive resin structure according to claim 1, which is used to form at least one of a coverlay and a solder resist for a flexible printed wiring board. A dry film, characterized in that at least one side of the photosensitive resin structure according to any one of claims 1 to 4 is supported or protected by the film. A flexible printed wiring board having a protective film, the protective film being a photosensitive resin structure according to any one of claims 1 to 4 formed on a flexible printed wiring board by light irradiation. Graphing, And by developing a pattern at one time by imaging. The flexible printed wiring board according to claim 6, wherein the developable adhesive layer (a) is formed by coating a photosensitive or non-photosensitive resin composition (a1) on the flexible printed wiring board. A laminated structure comprising a resin layer (A) composed of an alkali-developing resin composition containing no alkali-soluble polyimide, and a flexible layer laminated with the resin layer (A). Resin layer (B) of the flexible printed wiring board; the resin layer (B) is a photosensitive thermosetting resin composition containing an alkali-soluble resin having a fluorene imine ring, a photo-alkali generator, and a heat-reactive compound. Make up. The laminated structure according to claim 8, wherein the resin layer (A) and the resin layer (B) can be patterned together by light irradiation. For example, the laminated structure of claim 8 is used in at least one of a curved portion and a non-curved portion of a flexible printed wiring board. The laminated structure of claim 8 is used for at least any one of a cover film, a solder resist, and an interlayer insulating material of a flexible printed wiring board. A dry film, characterized in that at least one side of the laminated structure according to any one of claims 8 to 11 is supported or protected by the film. A flexible printed wiring board characterized by having an insulating film formed on the flexible printed wiring board as a layer of the laminated structure according to any one of claims 8 to 11 and irradiated with light. And the graphics, Yu Xian A pattern is formed in the image liquid at one time. A method for manufacturing a flexible printed wiring board, comprising the steps of forming at least one layer of an alkali-developing photosensitive resin composition (A1) containing no alkali-soluble polyimide on the flexible printed wiring board. Step of forming a resin layer (A) composed of) to form at least one layer of photosensitive heat containing an alkali-soluble resin having a fluorene imine ring, a photobase generator, and a thermally reactive compound on the resin layer (A). A step of the resin layer (B) composed of the curable resin composition (B1), a step of irradiating light into a pattern on the resin layers (A) and (B) formed in the foregoing step, and heating in the foregoing step Steps of the light-irradiated resin layers (A) and (B), and an alkali imaging of the light-irradiated resin layers (A) and (B) to form a cover film and at least one of a solder resist Steps. A flexible printed wiring board characterized by being manufactured by the method for manufacturing a flexible printed wiring board as claimed in claim 14.