JP2022075514A - Printed wiring board and method for manufacturing printed wiring board - Google Patents

Abstract

To provide a printed wiring board including a via having high conduction reliability.SOLUTION: A printed wiring board 11 includes a first conductor layer 8, a second conductor layer 3, an interlayer insulating layer 7, a via hole 6 penetrating through the interlayer insulating layer 7, and a via conductor 9 arranged in the via hole 6. The interlayer insulating layer 7 is a cured product of a negative type photosensitive resin composition containing a carboxyl group-containing resin (A), an unsaturated compound (B) having at least one ethylenically unsaturated bond in one molecule, and a photopolymerization initiator (C). The via hole 6 has a first end 61 on the side of the first conductor layer 8, a second end 62 on the side of the second conductor layer 3, and a small diameter part 63 that is between the first end 61 and the second end 62 and has a diameter smaller than the second end 62.SELECTED DRAWING: Figure 1

Description

The present disclosure generally relates to a printed wiring board and a method for manufacturing a printed wiring board, and more particularly to a printed wiring board provided with an interlayer insulating layer having via holes and via conductors, and a method for manufacturing the printed wiring board.

In the printed wiring board, vias may be formed on the interlayer insulating layer.

For example, in Patent Document 1, a step of irradiating a carbon dioxide laser from a plastic film adhered to the surface of an insulating layer containing 35% by mass or more of an inorganic filler to form a blind via having a top diameter of 100 μm or less. A method for manufacturing a multilayer printed wiring board including the above is disclosed.

Japanese Unexamined Patent Publication No. 2016-181731

However, according to the findings of the inventors, the invention described in Patent Document 1 has room for improvement in the conduction reliability of vias. Tapered vias tend to reduce conduction reliability.

Through research and development on the material of the interlayer insulating layer, the inventors have found that cracks may occur in the conductor of the via of the interlayer insulating layer, which deteriorates the conduction reliability.

An object of the present disclosure is to provide a printed wiring board having vias having high conduction reliability and a method for manufacturing the printed wiring board.

The printed wiring board according to one aspect of the present disclosure includes a first conductor layer, a second conductor layer, an interlayer insulating layer interposed between the first conductor layer and the second conductor layer, and the interlayer insulating layer. It is provided with a via hole penetrating the via hole and a via conductor arranged in the via hole and conducting the first conductor layer and the second conductor layer. The interlayer insulating layer is a negative type containing a carboxyl group-containing resin (A), an unsaturated compound (B) having at least one ethylenically unsaturated bond in one molecule, and a photopolymerization initiator (C). It is a cured product of the photosensitive resin composition of. The via hole is located between the first end, which is the end on the first conductor layer side, the second end, which is the end on the second conductor layer side, and the first end and the second end. It has a small diameter portion having a diameter smaller than the diameter of the second end.

The method for manufacturing a printed wiring board according to one aspect of the present disclosure is a method for manufacturing the printed wiring board, which has at least one of the carboxyl group-containing resin (A) and the ethylenically unsaturated bond in one molecule. A negative-type photosensitive resin composition containing the unsaturated compound (B) and the photopolymerization initiator (C), and a substrate having an insulating layer and the second conductor layer overlapping the insulating layer are prepared. Then, a film made from the photosensitive resin composition is layered on the substrate so as to cover the second conductor layer, and a negative pattern-like region of the film including the via hole pattern is exposed. Then, by performing a development treatment using an alkaline aqueous solution, the interlayer insulating layer and the via pores penetrating the interlayer insulating layer are produced.

According to one aspect of the present disclosure, it is possible to provide a printed wiring board having vias having high conduction reliability and a method for manufacturing the printed wiring board.

1A, 1B, 1C, 1D, and 1E are cross-sectional views showing a process of manufacturing a printed wiring board.

(1) Outline An embodiment according to the present disclosure will be described.

The printed wiring board 11 according to the present embodiment has an interlayer insulating layer 7 interposed between the first conductor layer 8, the second conductor layer 3, the first conductor layer 8 and the second conductor layer 3, and interlayer insulation. A via hole 6 penetrating the layer 7 and a via conductor 9 arranged in the via hole 6 and conducting the first conductor layer 8 and the second conductor layer 3 are provided (see FIG. 1E). The interlayer insulating layer 7 is a negative type containing a carboxyl group-containing resin (A), an unsaturated compound (B) having at least one ethylenically unsaturated bond in one molecule, and a photopolymerization initiator (C). It is a cured product of the photosensitive resin composition of. The via hole 6 is formed between the first end 61, which is the end on the first conductor layer 8 side, the second end 62, which is the end on the second conductor layer 3, and the first end 61 and the second end 62. It has a small diameter portion 63 having a diameter smaller than the diameter of the second end 62.

In the present embodiment, a negative type containing a carboxyl group-containing resin (A), an unsaturated compound (B) having at least one ethylenically unsaturated bond in one molecule, and a photopolymerization initiator (C). The interlayer insulating layer 7 is prepared from the photosensitive resin composition of the above. Therefore, the film 4 prepared from the photosensitive resin composition is exposed in a pattern and then developed with an alkaline aqueous solution to prepare an interlayer insulating layer 7 and a via hole 6 having a small diameter portion 63. Cheap.

It is presumed that the reason why the small diameter portion 63 is likely to be formed is as follows. When the film 4 formed from the negative photosensitive resin composition is exposed to light by irradiating the surface on which the first end 61 of the via hole 6 is formed, the inside of the film 4 is exposed. Due to the scattering of light, the deeper the film 4, the easier it is for the wider portion to cure. As a result, the uncured portion 5 that becomes the via hole 6 gradually becomes smaller, and a small diameter portion 63 having a diameter smaller than that of the first end 61 is easily formed. Further, on the deeper side of the film 4, the light is absorbed by the film 4, which makes it difficult for the light to reach, and the influence of light scattering is reduced, so that the curing of the film 4 is difficult to proceed. Therefore, the diameter of the second end 62 is larger than the diameter of the small diameter portion 63, and the via hole 6 tends to have a shape that expands from the small diameter portion 63 to the second end 62.

In particular, a film 4 having a film thickness of 5 μm or more and 100 μm or less is prepared from the photosensitive resin composition, and at least one wavelength in the wavelength range of 365 nm ± 65 nm is formed in the region of the film 4 excluding the circular portion having a diameter of 5 μm or more and 100 μm or less. When the film 4 is subsequently developed with an alkaline aqueous solution by irradiating it with ultraviolet rays having a spectral intensity, the via holes 6 are formed in a circular portion, and the via holes 6 have a small diameter portion 63. It is preferable that the photosensitive resin composition is provided. In this case, the diameter of the small diameter portion 63 of the via hole 6 is 65% or more and less than 100% with respect to the diameter of the second end 62, and the diameter of the first end 61 is 65% with respect to the diameter of the second end 62. As described above, the diameter of the first end 61 is preferably 100 μm or less. Such properties are feasible within the composition of the photosensitive resin composition, which will be described in detail later. The method of irradiating the film 4 with ultraviolet rays may be an exposure method using a negative mask or a direct drawing method. Examples of specific test methods and conditions are given in the Examples column.

Further, in the present embodiment, since the via hole 6 has such a shape, even if stress is generated in the via conductor 9 due to a load due to heat being applied to the via conductor 9, the via conductor 9 and the second via conductor 9 and the second via conductor 9 are stressed. Cracks are unlikely to occur at the interface with the conductor layer 3. Therefore, it is easy to obtain good conduction reliability between the first conductor layer 8 and the second conductor layer 3 by the via. This is because, as described above, in the present embodiment, the inner surface of the via hole 6 of the interlayer insulating layer 7 has a shape in which the diameter increases even from the small diameter portion 63 to the second end 62, so that stress is generated in the via conductor 9. It is presumed that this is because the stress is more likely to be concentrated on the small diameter portion 63 as compared with the second end 62 of the via.

The minimum diameter of the small diameter portion 63 is preferably 65% or more and less than 100% of the diameter of the second end 62. In this case, conduction reliability due to vias is particularly easy to obtain. The minimum diameter of the small diameter portion 63 is more preferably 95% or less of the diameter of the second end 62, and further preferably 90% or less. Further, the minimum diameter of the small diameter portion 63 is more preferably 67% or more of the diameter of the second end 62, and further preferably 79% or more.

The diameter of the first end 61 is preferably 65% or more with respect to the diameter of the second end 62. In this case, the via conductor 9 can be easily manufactured by infiltrating the plating solution into the via hole 6. That is, it is easy to manufacture the via conductor 9 by the plating method. Therefore, it is easy to obtain better conduction reliability. From the viewpoint of obtaining good resolution at the time of producing the via hole 6, the diameter of the first end 61 is more preferably 70% or more, more preferably 75% or more with respect to the diameter of the second end 62. Is more preferable, and 80% or more is particularly preferable. Further, the diameter of the first end 61 is preferably less than 130%, more preferably less than 120%, still more preferably less than 110%, and 100% with respect to the diameter of the second end 62. Less than is particularly preferred.

Further, the diameter of the first end 61 is preferably 100 μm or less. In this case, it becomes easy to fabricate the via conductor 9 in the via hole 6 by a plating method or the like. Therefore, it is easy to obtain better conduction reliability. The diameter of the first end 61 is, for example, 5 μm or more.

(2) Photosensitive Resin Composition The details of the photosensitive resin composition of the present embodiment will be specifically described below. In the following description, "(meth) acrylic" means at least one of "acrylic" and "methacrylic". For example, (meth) acrylate means at least one of acrylate and methacrylate.

The photosensitive resin composition according to the present embodiment includes a carboxyl group-containing resin (A), an unsaturated compound (B) having at least one ethylenically unsaturated bond in one molecule, and a photopolymerization initiator (C). And contains.

The carboxyl group-containing resin (A) preferably contains a carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton represented by the following formula (1). When the carboxyl group-containing resin (A) has a bulky bisphenol fluorene skeleton, light scattering is less likely to occur in a deep part when the film 4 formed from the photosensitive resin composition is irradiated with ultraviolet rays. Further, since the carboxyl group-containing resin (A1) has a bisphenol fluorene skeleton, high heat resistance and insulation reliability can be imparted to the cured product of the photosensitive resin composition.

In formula (1), R ₁ to R ₈ are independently hydrogen, an alkyl group having 1 to 5 carbon atoms, or a halogen. That is, each of R ₁ to R ₈ in the formula (1) may be hydrogen, but may be an alkyl group having 1 to 5 carbon atoms or a halogen. Even if hydrogen in the aromatic ring is substituted with a low molecular weight alkyl group or halogen, the physical properties of the carboxyl group-containing resin (A1) are not adversely affected, but rather the substitution causes the carboxyl group-containing resin (A1) to be contained. This is because the heat resistance or flame retardancy of the cured product of the photosensitive resin composition may be improved.

The carboxyl group-containing resin (A1) is obtained by reacting, for example, an epoxy compound (a1) having a bisphenolfluorene skeleton represented by the formula (1) with an unsaturated group-containing carboxylic acid (a2), and an intermediate obtained thereby. It is synthesized by reacting the body with an acid anhydride (a3).

The epoxy compound (a1) has, for example, a structure represented by the following formula (2). N in the equation (2) is, for example, an integer in the range of 0 to 20. In order to appropriately control the molecular weight of the carboxyl group-containing resin (A1), the average of n is more preferably in the range of 0 to 1. When the average of n is in the range of 0 to 1, the excessive increase in the molecular weight of the carboxyl group-containing resin (A1) is likely to be suppressed. Further, in the formula (2), R ₁ to R ₈ are independently hydrogen, an alkyl group having 1 to 5 carbon atoms, or a halogen.

The unsaturated group-containing carboxylic acid (a2) contains, for example, a compound having only one ethylenically unsaturated group in one molecule. More specifically, the unsaturated group-containing carboxylic acid (a2) may be, for example, acrylic acid, methacrylic acid, ω-carboxy-polycaprolactone (n≈2) monoacrylate, crotonic acid, cinnamic acid, 2-acryloyloxyethyl succinate. Acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl phthalic acid, 2-acryloyloxypropylphthalic acid, 2-methacryloyloxypropylphthalic acid, 2-acryloyloxyethyl maleic acid, 2-methacryloyloxyethyl maleic acid, β-carboxyethyl acrylate, 2-acryloyloxyethyl tetrahydrophthalic acid, 2-methacryloyloxyethyl tetrahydrophthalic acid, 2-acryloyloxyethyl hexahydrophthalic acid, and 2-methacryloyloxyethyl hexahydro It contains at least one compound selected from the group consisting of phthalic acid. Preferably, the unsaturated group-containing carboxylic acid (a2) contains acrylic acid. When the unsaturated group-containing carboxylic acid (a2) contains acrylic acid, the acrylic acid is preferably contained in an amount of 50 mol% or more, preferably 80 mol% or more, of the unsaturated group-containing carboxylic acid (a2). Is more preferable, and it is more preferably contained in an amount of 85 mol% or more, and particularly preferably contained in an amount of 90 mol% or more.

An appropriate method can be adopted for reacting the epoxy compound (a1) with the unsaturated group-containing carboxylic acid (a2). For example, an unsaturated group-containing carboxylic acid (a2) is added to a solvent solution of the epoxy compound (a1), and if necessary, a thermal polymerization inhibitor and a catalyst are added and mixed by stirring to obtain a reactive solution. An intermediate can be obtained by reacting this reactive solution by a conventional method at a temperature of preferably 60 ° C. or higher and 150 ° C. or lower, more preferably 80 ° C. or higher and 120 ° C. or lower. The solvent in this case is, for example, ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, and ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate and propylene. It can contain at least one component selected from the group consisting of acetic acid esters such as glycol monomethyl ether acetate and dialkyl glycol ethers. The thermal polymerization inhibitor can contain at least one component selected from the group consisting of, for example, hydroquinone, methylhydroquinone, and hydroquinone monomethyl ether. The catalyst is selected from the group consisting of tertiary amines such as benzyldimethylamine and triethylamine, quaternary ammonium salts such as trimethylbenzylammonium chloride and methyltriethylammonium chloride, triphenylfosphin and triphenylstibine. It can contain at least one component.

It is particularly preferred that the catalyst contains triphenylphosphine. That is, it is preferable to react the epoxy compound (a1) with the unsaturated group-containing carboxylic acid (a2) in the presence of triphenylphosphine. In this case, the ring-opening addition reaction between the epoxy group and the unsaturated group-containing carboxylic acid (a2) in the epoxy compound (a1) is particularly promoted, and the reaction rate (conversion) is 95% or more, 97% or more, or almost 100%. Rate) can be achieved.

It is also preferable to react the epoxy compound (a1) with the unsaturated group-containing carboxylic acid (a2) under air bubbling. In this case, the addition polymerization reaction of the unsaturated group can be suppressed, and the increase in the molecular weight of the intermediate and the gelation of the solution of the intermediate can be suppressed. In addition, excessive coloring of the carboxyl group-containing resin (A1), which is the final product, can be suppressed.

When the epoxy compound (a1) is reacted with the unsaturated group-containing carboxylic acid (a2), the amount of the unsaturated group-containing carboxylic acid (a2) with respect to 1 mol of the epoxy group of the epoxy compound (a1) is 0.8 mol. It is preferably 1.2 mol or less. In this case, a photosensitive resin composition having excellent photosensitivity and stability can be obtained.

The intermediate thus obtained comprises a hydroxyl group generated by the reaction of the epoxy group of the epoxy compound (a1) with the carboxyl group of the unsaturated group-containing carboxylic acid (a2).

Next, the intermediate is reacted with the acid anhydride (a3). The acid anhydride (a3) contains, for example, acid dianhydride (a4).

The acid anhydride (a4) is a compound having two acid anhydride groups. The acid dianhydride (a4) can contain an anhydride of tetracarboxylic acid. The acid dianhydride (a4) is, for example, 1,2,4,5-benzenetetracarboxylic acid dianhydride, benzophenone tetracarboxylic acid dianhydride, methylcyclohexenetetracarboxylic acid dianhydride, tetracarboxylic acid dianhydride, etc. Naphthalene-1,4,5,8-tetracarboxylic acid dianhydride, ethylenetetracarboxylic acid dianhydride, 9,9'-bis (3,4-dicarboxyphenyl) fluorene dianhydride, glycerinbis anhydrotri Meritate Monoacetate, Ethylene Glycolbisanhydrotrimeritate, 3,3', 4,4'-Diphenylsulfone Tetracarboxylic Acid Dianhydride, 1,3,3a, 4,5,9b-Hexahydro-5 (Tetrahydro) -2,5-dioxo-3-franyl) naphtho [1,2-c] furan-1,3-dione, 1,2,3,4-butanetetracarboxylic acid dianhydride, and 3,3', 4 , 4'-Can contain at least one compound selected from the group consisting of biphenyltetracarboxylic acid dianhydride. In particular, it is preferable that the acid dianhydride (a4) contains 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride. In this case, while ensuring good developability of the photosensitive resin composition, it is possible to suppress the tackiness of the film 4 produced from the photosensitive resin composition and improve the insulation reliability and plating resistance of the cured product.

The acid anhydride (a3) may contain an acid anhydride (a5). The acid anhydride (a5) is a compound having one acid anhydride group. The acid monoanhydride (a5) can contain an anhydride of a dicarboxylic acid. The acid monoanhydride (a5) is, for example, phthalic anhydride, 1,2,3,6-tetrahydroanhydride, methyltetrahydrophthalic anhydride, methylnadic acid anhydride, hexahydrophthalic anhydride, methylhexa. Hydrophthalic anhydride, succinic anhydride, methylsuccinic anhydride, maleic acid anhydride, citraconic acid anhydride, glutaric acid anhydride, cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, and It can contain one or more compounds selected from the group consisting of itaconic acid anhydride. In particular, it is preferable that the acid monoanhydride (a5) contains 1,2,3,6-tetrahydrophthalic anhydride. That is, it is preferable that the acid anhydride (a3) contains 1,2,3,6-tetrahydrophthalic anhydride. In this case, while ensuring good developability of the photosensitive resin composition, the tackiness of the film 4 formed from the photosensitive resin composition is further suppressed, and the insulation reliability and plating resistance of the cured product are further improved. can. The amount of 1,2,3,6-tetrahydrophthalic anhydride is preferably in the range of 20 mol% or more and 100 mol% or less, and 40 mol% or more and 100 mol% or less, based on the whole acid monoanhydride (a5). It is more preferable that it is within the range of, but it is not limited to this.

An appropriate method can be adopted for reacting the intermediate with the acid anhydride (a3). For example, the acid anhydride (a3) is added to the solvent solution of the intermediate, and if necessary, a thermal polymerization inhibitor and a catalyst are added and mixed by stirring to obtain a reactive solution. By reacting this reactive solution at a temperature of preferably 60 ° C. or higher and 150 ° C. or lower, particularly preferably 80 ° C. or higher and 120 ° C. or lower by a conventional method, a carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton can be obtained. As the solvent, catalyst and polymerization inhibitor, appropriate ones can be used, and the solvent, catalyst and polymerization inhibitor used at the time of synthesizing the intermediate can also be used as they are.

It is particularly preferred that the catalyst contains triphenylphosphine. That is, it is preferable to react the intermediate with the acid anhydride (a3) in the presence of triphenylphosphine. In this case, the reaction between the intermediate and the acid anhydride (a3) is particularly promoted, and a reaction rate (conversion rate) of 90% or more, 95% or more, 97% or more, or almost 100% can be achieved.

When the acid anhydride (a3) contains the acid dianhydride (a4), the amount of the acid dianhydride (a4) is 0.05 mol or more and 0 with respect to 1 mol of the epoxy group of the epoxy compound (a1). It is preferably .24 mol or less. In this case, a carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton in which the acid value and the molecular weight are appropriately adjusted can be easily obtained.

When the acid anhydride (a3) further contains the acid anhydride (a5), the amount of the acid anhydride (a5) is 0.3 mol with respect to 1 mol of the epoxy group of the epoxy compound (a1). It is preferably 0.7 or more and 0.7 or less. In this case, a carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton in which the acid value and the molecular weight are appropriately adjusted can be easily obtained.

It is also preferable to react the intermediate with the acid anhydride (a3) under air bubbling. In this case, by suppressing an excessive increase in molecular weight of the carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton to be produced, the developability of the photosensitive resin composition with an alkaline aqueous solution is particularly improved.

The components other than the carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton in the photosensitive resin composition will be described.

As described above, the photosensitive resin composition comprises a carboxyl group-containing resin (A), an unsaturated compound (B) having at least one ethylenically unsaturated bond in one molecule, and a photopolymerization initiator (C). And contains.

The carboxyl group-containing resin (A) may contain only a carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton, or may contain only a carboxyl group-containing resin other than the carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton. You may. Alternatively, both the carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton and the carboxyl group-containing resin other than the carboxyl group-containing resin (A1) may be contained. The carboxyl group-containing resin other than the carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton includes a carboxyl group-containing resin having no bisphenol fluorene skeleton (hereinafter, also referred to as a carboxyl group-containing resin (A2)).

The carboxyl group-containing resin (A2) can contain, for example, a compound having a carboxyl group and no photopolymerizability (hereinafter referred to as (A2-1) component). The component (A2-1) contains, for example, a polymer of an ethylenically unsaturated monomer containing an ethylenically unsaturated compound having a carboxyl group. The ethylenically unsaturated compound having a carboxyl group can contain a compound such as acrylic acid, methacrylic acid, and ω-carboxy-polycaprolactone (n≈2) monoacrylate. The ethylenically unsaturated compound having a carboxyl group can also contain a reaction product of pentaerythritol triacrylate, pentaerythritol trimethacrylate and the like with dibasic acid anhydride. The ethylenically unsaturated monomer is 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl phthalate, a linear or branched aliphatic or alicyclic group (however, It may further contain an ethylenically unsaturated compound having no carboxyl group, such as a (meth) acrylic acid ester (which may have a partially unsaturated bond in the ring).

The carboxyl group-containing resin (A2) may contain a compound having a carboxyl group and an ethylenically unsaturated group (hereinafter referred to as (A2-2) component). Further, the carboxyl group-containing resin (A2) may contain only the component (A2-2). The component (A2-2) is, for example, an intermediate which is a reaction product of an epoxy compound (x1) having two or more epoxy groups in one molecule and an ethylenically unsaturated compound (x2), a polyvalent carboxylic acid and the like. It contains a resin (referred to as the first resin (x)) which is a reaction product with at least one compound (x3) selected from the group of anhydrides. In the first resin (x), for example, the compound (x3) is added to an intermediate obtained by reacting an epoxy group in an epoxy compound (x1) with a carboxyl group in an ethylenically unsaturated compound (x2). Obtained by letting. The epoxy compound (x1) can contain an appropriate epoxy compound such as a cresol novolac type epoxy compound, a phenol novolac type epoxy compound, and a biphenyl novolac type epoxy compound. In particular, the epoxy compound (x1) preferably contains at least one compound selected from the group of biphenyl novolac type epoxy compounds and cresol novolac type epoxy compounds. The epoxy compound (x1) may contain only a biphenyl novolac type epoxy compound, or may contain only a cresol novolac type epoxy compound. In this case, since the main chain of the epoxy compound (x1) contains an aromatic ring, the degree to which the cured product of the photosensitive resin composition is significantly corroded by an oxidizing agent containing, for example, potassium permanganate is reduced. can do. The epoxy compound (x1) may contain a polymer of the ethylenically unsaturated compound (z). The ethylenically unsaturated compound (z) contains a compound (z1) having an epoxy group such as glycidyl (meth) acrylate, or further has no epoxy group such as 2- (meth) acryloyloxyethyl phthalate. Contains compound (z2). The ethylenically unsaturated compound (x2) preferably contains at least one of acrylic acid and methacrylic acid. The compound (x3) contains one or more compounds selected from the group consisting of polyvalent carboxylic acids such as phthalic acid, tetrahydrophthalic acid, and methyltetrahydrophthalic acid, and anhydrides of these polyvalent carboxylic acids. .. In particular, the compound (x3) preferably contains at least one polyvalent carboxylic acid selected from the group of phthalic acid, tetrahydrophthalic acid and methyltetrahydrophthalic acid.

The component (A2-2) is a resin (second) which is a reaction product of a polymer of an ethylenically unsaturated monomer containing an ethylenically unsaturated compound having a carboxyl group and an ethylenically unsaturated compound having an epoxy group. The resin (y) of the above may be contained. The ethylenically unsaturated monomer may further contain an ethylenically unsaturated compound having no carboxyl group. The second resin (y) is obtained by reacting an ethylenically unsaturated compound having an epoxy group with a part of the carboxyl group in the polymer. The ethylenically unsaturated monomer may further contain an ethylenically unsaturated compound having no carboxyl group. The ethylenically unsaturated compound having a carboxyl group contains, for example, a compound such as acrylic acid, methacrylic acid, ω-carboxy-polycaprolactone (n≈2) monoacrylate, pentaerythritol triacrylate, and pentaerythritol trimethacrylate. Ethyl unsaturated compounds having no carboxyl group include, for example, 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl phthalate, linear or branched aliphatic or fat. It contains a compound such as a (meth) acrylic acid ester of a cyclic group (provided that the ring may have a partially unsaturated bond). The ethylenically unsaturated compound having an epoxy group preferably contains glycidyl (meth) acrylate.

The carboxyl group-containing resin (A) contains only the carboxyl group-containing resin (A1), only the carboxyl group-containing resin (A2), or the carboxyl group-containing resin (A1) and the carboxyl group-containing resin (A2). The carboxyl group-containing resin (A) preferably contains the carboxyl group-containing resin (A1) in an amount of 25% by mass or more, more preferably 40% by mass or more, still more preferably 60% by mass or more, and 100%. It is particularly preferable to contain it in an amount of% by mass. In this case, excellent photosensitivity of the photosensitive resin composition and developability with an alkaline aqueous solution can be ensured. Further, the heat resistance and insulation reliability of the cured product of the photosensitive resin composition can be particularly improved. Further, the tackiness of the film 4 formed from the photosensitive resin composition can be sufficiently reduced.

The weight average molecular weight of the carboxyl group-containing resin (A) is preferably 700 or more and 100,000 or less. When the weight average molecular weight of the carboxyl group-containing resin (A) is 700 or more, the tackiness of the film 4 formed from the photosensitive resin composition is easily suppressed, and the insulation reliability of the cured product of the photosensitive resin composition is easily suppressed. And the plating resistance can be improved. When the weight average molecular weight of the carboxyl group-containing resin (A) is 100,000 or less, the developability of the photosensitive resin composition with an alkaline aqueous solution tends to be good. The weight average molecular weight of the carboxyl group-containing resin (A) is more preferably 900 or more and 60,000 or less, further preferably 1200 or more and 10000 or less, and particularly preferably 1400 or more and 5000 or less. The weight average molecular weight of the carboxyl group-containing resin (A) is calculated, for example, from the measurement results under the following conditions by gel permeation chromatography.

GPC device: SHOWEX SYSTEM 11, manufactured by Showa Denko KK
Column: 4 series of SHODEX KF-800P, KF-005, KF-003, KF-001,
Mobile phase: THF,
Flow rate: 1 ml / min,
Column temperature: 45 ° C,
Detector: RI,
Conversion: Polystyrene.

The carboxyl group-containing resin (A) preferably contains a component having an acid value of 65 mgKOH / g or more and 150 mgKOH / g or less. In this case, the developability of the photosensitive resin composition with the alkaline aqueous solution is particularly improved, and by developing the exposed film 4 with the alkaline aqueous solution, the via hole 6 having the small diameter portion 63 is particularly easy to be produced. The acid value is more preferably 70 mgKOH / g or more and 145 mgKOH / g or less, further preferably 75 mgKOH / g or more and 140 mgKOH / g or less, and particularly preferably 85 mgKOH / g or more and 135 mgKOH / g or less.

The unsaturated compound (B) can impart photocurability to the photosensitive resin composition. The unsaturated compound (B) is a monofunctional (meth) acrylate such as 2-hydroxyethyl (meth) acrylate; as well as a diethylene glycol di (meth) acrylate, a trimethylol propandi (meth) acrylate, and a trimethylol propanetri (meth). Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ε-caprolactone-modified pentaeristol hexaacrylate, tricyclodecandy It can contain at least one compound selected from the group consisting of polyfunctional (meth) acrylates such as methanol di (meth) acrylates.

In particular, the unsaturated compound (B) preferably contains a trifunctional compound, that is, a compound having three unsaturated bonds in one molecule. In this case, the resolvability when the film 4 formed from the photosensitive resin composition is exposed and developed is improved, and the developability of the photosensitive resin composition with an alkaline aqueous solution is particularly improved. Trifunctional compounds include, for example, trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, pentaeristoltri (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate and ε-caprolactone-modified. It can contain at least one compound selected from the group consisting of tris- (2-acryloxyethyl) isocyanurate and ethoxylated glycerin tri (meth) acrylate.

The unsaturated compound (B) also preferably contains a phosphorus-containing compound (phosphorus-containing unsaturated compound). In this case, the flame retardancy of the cured product of the photosensitive resin composition is improved. Examples of the phosphorus-containing unsaturated compound include 2-methacryloyloxyethyl acid phosphate (specific examples, part numbers light ester P-1M and light ester P-2M manufactured by Kyoeisha Chemical Co., Ltd.) and 2-acryloyloxyethyl acid phosphate. (Specific example, product number light acrylate P-1A manufactured by Kyoeisha Chemical Co., Ltd.), diphenyl-2-methacryloyloxyethyl phosphate (specific example, product number MR-260 manufactured by Daihachi Kogyo Co., Ltd.), and Showa Polymer Co., Ltd. HFA series (for example, product number HFA-6003 which is an addition reaction product of dipentaerystoluhexaacrylate and HCA (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), and HFA-6007, part number HFA-3003, which is an addition reaction product of caprolactone-modified dipentaerystoluhexaacrylate and HCA (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), and HFA- It can contain at least one compound selected from the group consisting of 6127 etc.).

The unsaturated compound (B) may contain a prepolymer. The prepolymer is at least one selected from the group consisting of, for example, a prepolymer obtained by polymerizing a monomer having an ethylenically unsaturated bond and then adding an ethylenically unsaturated group, and oligo (meth) acrylate prepolymers. Can contain the compound of. Oligo (meth) acrylate prepolymers include, for example, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) acrylate, alkyd resin (meth) acrylate, silicone resin (meth) acrylate, and spirane resin (meth) acrylate. It can contain at least one component selected from the group consisting of.

The photopolymerization initiator (C) is a light containing at least one selected from the group consisting of an acylphosphine oxide-based photopolymerization initiator, an α-aminoalkylphenone-based photopolymerization initiator, and an oxime ester-based photopolymerization initiator. It preferably contains a polymerization initiator (C1). In this case, when the photosensitive resin composition is exposed to ultraviolet rays, high light absorption can be imparted to the photosensitive resin composition. When the photosensitive resin composition has good light absorption, light is easily absorbed when the film 4 formed from the photosensitive resin composition is exposed, so that light curing is likely to proceed. Further, by absorbing light in the film 4, the amount of light reaching the deep part is reduced. For this reason, the influence of light scattering is particularly unlikely to occur in the deep part, and the photocuring of the film 4 is particularly difficult to proceed in the deep part as compared with the surface. Therefore, when the via hole 6 is produced by the photolithography method, the small diameter portion 63 is particularly likely to be formed.

It is more preferable that the photopolymerization initiator (C1) contains an acylphosphine oxide-based photopolymerization initiator. In this case, the photosensitive resin composition can impart high light absorption.

The acylphosphine oxide-based photopolymerization initiator is a monoacylphosphine oxide-based agent such as 2,4,6-trimethylbenzoyl-diphenyl-phosphinoxide, 2,4,6-trimethylbenzoyl-ethyl-phenyl-phosphinate. Photopolymerization initiator, bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphinoxide, bis- (2,6-dichloro) Benzoyl) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphinoxide, bis- (2,6-dimethoxybenzoyl) phenylphosphinoxide, bis- (2,6) -Dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,5-dimethylphenylphosphinoxide, bis- (2,4,6-trimethylbenzoyl) At least one component selected from the group consisting of bisacylphosphine oxide-based photopolymerization initiators such as phenylphosphine oxide, (2,5,6-trimethylbenzoyl) -2,4,4-trimethylpentylphosphinoxide. Can be contained. The acylphosphine oxide-based photopolymerization initiator contains at least one of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis- (2,4,6-trimethylbenzoyl) phenylphosphine oxide. , And more preferably 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

The α-aminoalkylphenone-based photopolymerization initiator is, for example, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpho). Selected from the group consisting of phosphophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone. It can contain at least one component.

Oxime ester-based photopolymerization initiators include, for example, 1,2-octanedione, 1- [4- (phenylthio)-, 2- (О-benzoyloxime)], etanone, 1- [9-ethyl-6- (2). -Methylbenzoyl) -9H-carbazole-3-yl]-, 1- (O-acetyloxime) can contain at least one component selected from the group.

The photopolymerization initiator (C) may contain a photopolymerization initiator (C2) containing a component other than the above, in addition to the photopolymerization initiator (C1) containing the above components. The photopolymerization initiator (C2) preferably contains at least one of an α-hydroxyacetophenone-based photopolymerization initiator and a thioxanthone-based photopolymerization initiator. In this case, particularly high light absorption can be imparted to the photosensitive resin composition. The photopolymerization initiator (C2) more preferably contains an α-hydroxyacetophenone-based photopolymerization initiator.

The α-hydroxyacetophenone-based photopolymerization initiator preferably contains, for example, 1-hydroxycyclohexyl-phenylketone 1-hydroxycyclohexyl-phenylketone.

The thioxanthone-based photopolymerization initiator preferably contains, for example, 2,4-diethylthioxanthene-9-one.

It is also preferable that the photopolymerization initiator (C) contains 4,4-bis (diethylamino) benzophenone (C3). That is, the photosensitive resin composition contains a photopolymerization initiator (C1) and a 4,4-bis (diethylamino) benzophenone (C3), or a photopolymerization initiator (C1), a photopolymerization initiator (C2) and 4 , 4-Bis (diethylamino) benzophenone (C3) is also preferred. In this case, when the film 4 formed from the photosensitive resin composition is partially exposed and then developed, the curing of the unexposed portion is particularly likely to be suppressed. Therefore, it becomes particularly easy to form the via hole 6 having the small diameter portion 63.

The amount of 4,4-bis (diethylamino) benzophenone (C3) is preferably in the range of 0.5% by mass or more and 20% by mass or less with respect to the photopolymerization initiator (C1). When 4,4-bis (diethylamino) benzophenone (C3) is 0.5% by mass or more, curing of the unexposed portion is particularly likely to be suppressed. Further, when the content of 4,4-bis (diethylamino) benzophenone (C3) is 20% by mass or less, 4,4-bis (diethylamino) benzophenone (C3) inhibits the electrical insulation of the cured product of the photosensitive resin composition. It's hard to do. The bis (diethylamino) benzophenone (C3) is particularly preferably in the range of 1% by mass or more and 18% by mass or less with respect to the photopolymerization initiator (C1). When the photosensitive resin composition contains the organic filler (E), the organic filler (E) may cause light scattering in the photosensitive resin composition at the time of exposure. In this case, there may be a problem that good resolution cannot be obtained with the photosensitive resin composition. Therefore, it may be difficult to form the small diameter portion 63 in the via hole 6. However, when 4,4-bis (diethylamino) benzophenone (C3) is within the above range, the photosensitive resin composition tends to have good resolution, and therefore the small diameter portion 63 is particularly formed in the via hole 6. It becomes easy to be done.

The photosensitive resin composition preferably contains the epoxy resin (D). The epoxy resin (D) can impart thermosetting property to the photosensitive resin composition. The epoxy resin (D) preferably contains a crystalline epoxy resin. In this case, the developability of the photosensitive resin composition can be improved. Further, the epoxy resin (D) may further contain an amorphous epoxy resin. Here, the "crystalline epoxy resin" is an epoxy resin having a melting point, and the "amorphous epoxy resin" is an epoxy resin having no melting point.

The crystalline epoxy resin is, for example, 1,3,5-tris (2,3-epoxypropyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, hydroquinone type crystal. Sex epoxy resin (specific example, product name YDC-1312 manufactured by Nittetsu Chemical & Materials Co., Ltd.), biphenyl type crystalline epoxy resin (specific example, product name YX-4000 manufactured by Mitsubishi Chemical Corporation), diphenyl ether type crystalline epoxy resin (Specific example, product number YSLV-80DE manufactured by Nittetsu Chemical & Materials Co., Ltd.), bisphenol type crystalline epoxy resin (specific example, product names YSLV-70XY and YSLV-80XY manufactured by Nittetsu Chemical & Materials Co., Ltd.), Tetrakiss It is preferable to contain one or more components selected from the group consisting of a phenol ethane type crystalline epoxy resin (specific example, product number GTR-1800 manufactured by Nippon Kayaku Co., Ltd.) and a bisphenol fluorene type crystalline epoxy resin.

The crystalline epoxy resin preferably has two or more epoxy groups in one molecule. In this case, it is possible to make it difficult for cracks to occur in the cured product of the photosensitive resin composition as the temperature changes repeatedly.

The crystalline epoxy resin preferably has an epoxy equivalent of 150 g / eq or more and 300 g / eq or less. This epoxy equivalent is the gram weight of a crystalline epoxy resin containing 1 gram equivalent of an epoxy group. The crystalline epoxy resin has a melting point. The melting point of the crystalline epoxy resin is, for example, 70 ° C. or higher and 180 ° C. or lower.

In particular, it is preferable that the epoxy compound (D) contains a crystalline epoxy resin having a melting point of 110 ° C. or lower. In this case, the developability of the photosensitive resin composition with an alkaline aqueous solution is particularly improved. The crystalline epoxy resin having a melting point of 110 ° C. or lower is, for example, a biphenyl type epoxy resin (specific example, product number YX-4000 manufactured by Mitsubishi Chemical Corporation) or a diphenyl ether type epoxy resin (specific example, manufactured by Nittetsu Chemical & Material Chemical Co., Ltd.). At least selected from the group consisting of product numbers YSLV-80DE), bisphenol type epoxy resins (specific examples, product numbers YSLV-70XY and YSLV-80XY manufactured by Nittetsu Chemical & Materials Co., Ltd.), and bisphenol fluorene type crystalline epoxy resins. Can contain a kind of ingredient.

Examples of the amorphous epoxy resin include a phenol novolac type epoxy resin (specific example, product number EPICLON N-775 manufactured by DIC Co., Ltd.) and a cresol novolac type epoxy resin (specific example, product number EPICLON N-695 manufactured by DIC Co., Ltd.). , Bisphenol A novolak type epoxy resin (specific example, product number EPICLON N-865 manufactured by DIC Co., Ltd.), Bisphenol A type epoxy resin (specific example, product number jER1001 manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resin (specific example). Mitsubishi Chemical Co., Ltd. part number jER4004P), bisphenol S type epoxy resin (specific example, DIC Co., Ltd. part number EPICLON EXA-1514), bisphenol AD type epoxy resin, biphenyl novolak type epoxy resin (specific example, Nippon Kayaku) Part number NC-3000 manufactured by Co., Ltd.), hydrogenated bisphenol A type epoxy resin (part number ST-4000D manufactured by Nittetsu Chemical & Materials Co., Ltd. as a specific example), naphthalene type epoxy resin (part number manufactured by DIC Co., Ltd. as a specific example). EPICLON HP-4032, EPICLON HP-4700, EPICLON HP-4770), tertiary butyl catechol type epoxy resin (specific example, product number EPICLON HP-820 manufactured by DIC Co., Ltd.), dicyclopentadiene type epoxy resin (specific example, DIC) EPICLON HP-7200), Adamantane type epoxy resin (specific example, product number ADAMANTATEX-E-201 manufactured by Idemitsu Kosan Co., Ltd.), special bifunctional epoxy resin (specific example, product number YL7175 manufactured by Mitsubishi Chemical Corporation). -500, and YL7175-1000; Part numbers EPICLON TSR-960, EPICLON TER-601, EPILON TSR-250-80BX, EPICLON 1650-75MPX, EPICLON EXA-4850, EPICLON EXA-4816, EPICLON, manufactured by DIC Co., Ltd. , And EPICLON EXA-9726; Nittetsu Chemical & Materials Co., Ltd. part number YSLV-120TE), rubber-like core shell polymer-modified bisphenol A type epoxy resin (specific example, Kaneka Co., Ltd. part number MX-156), rubber-like core shell Polymer-modified bisphenol F-type epoxy resin (specifically As an example, it contains at least one component selected from the group consisting of Kaneka Corporation's product number MX-136) and rubber particle-containing bisphenol F-type epoxy resin (specifically, Kaneka Corporation's product number Kaneace MX-130). It is preferable to do so.

When the photosensitive resin composition contains the epoxy resin (D), the photosensitive resin composition preferably contains both a crystalline epoxy resin and an amorphous epoxy resin. In this case, the plating resistance and the insulating property of the cured product produced from the photosensitive resin composition can be further improved.

The epoxy resin (D) may contain a phosphorus-containing epoxy resin. In this case, the flame retardancy of the cured product of the photosensitive resin composition is improved. The phosphorus-containing epoxy resin may be contained in the crystalline epoxy resin or may be contained in the amorphous epoxy resin. Phosphorus-containing epoxy resins include, for example, phosphoric acid-modified bisphenol F-type epoxy resin (specific examples, product numbers EPICLON EXA-9726 and EPICLON EXA-9710 manufactured by DIC Corporation) and Epototo FX manufactured by Nittetsu Chemical & Materials Co., Ltd. -305 mag.

The photosensitive resin composition preferably does not contain a filler. In this case, since the scattering of light in the deep part of the film 4 is suppressed, the via hole 6 having the small diameter portion 63 becomes particularly easy to be formed. When the photosensitive resin composition contains a filler, it is preferable that the material, particle size, and blending amount of the filler are appropriately set so that light scattering is appropriately less likely to occur in the film 4.

The photosensitive resin composition may contain an organic filler (E). The organic filler (E) does not contain melamine. In this case, it is preferable that the material, particle size and blending amount of the organic filler (E) are appropriately set as described above. The organic filler (E) imparts thixophilicity to the photosensitive resin composition, thereby improving the storage stability of the photosensitive resin composition. In addition, the cured product has improved adhesion to the plating layer. The organic filler (E) preferably has a reactive group. By having a reactive group, the organic filler (E) has high compatibility in the photosensitive resin composition, and by imparting stronger thixo property to the photosensitive resin composition, the photosensitive resin composition Storage stability is further improved. In addition, the adhesion between the cured product and the plating layer is further improved. The reactive group of the organic filler (E) more preferably contains, for example, at least one group selected from the group consisting of a carboxyl group, an amino group, an epoxy group, a vinyl group, and a hydroxyl group, preferably a carboxyl group and an amino group. It is more preferable to contain at least one of the groups. In this case, the storage stability of the photosensitive resin composition is further improved. Further, the cured product has further improved adhesion to the plating layer. It is particularly preferable that the reactive group contained in the organic filler (E) contains a carboxyl group. In this case, the developability of the photosensitive resin composition is improved. At the same time, the carboxyl group of the organic filler (E) can react with the epoxy resin (D) in the photosensitive resin composition during thermosetting. As a result, the cured product after thermosetting can contain the organic filler (E) uniformly dispersed inside the cured product. Further, the unreacted carboxyl group of the organic filler (E) can be modified at the stage of roughening the surface of the cured product. That is, among the organic fillers (E) contained in the cured product, the organic filler (E) located near the surface of the cured product is likely to be deteriorated at the stage of roughening the surface of the cured product. The organic filler (E) thus denatured is easily removed from the cured product when a rough surface is applied to the cured product. This makes it possible to impart a rough surface to the surface of the cured product and improve the adhesion between the cured product and the plating layer. Furthermore, since the organic filler (E) contains a carboxyl group, it is possible to reduce the non-uniformity of the coating film due to the fluidity of the photosensitive resin composition. Thereby, it is possible to easily make the film thickness of the layer formed of the photosensitive resin composition uniform. Further, it becomes easy to form a via hole 6 having a small diameter portion 63 in the interlayer insulating layer 7 made of the photosensitive resin composition.

When the organic filler (E) contains a carboxyl group, the carboxyl group is produced by polymerizing or cross-linking a carboxylic acid monomer such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. Formed as a side chain in an object. The carboxylic acid monomer has a carboxyl group and a polymerizable unsaturated double bond. Since the organic filler (E) enhances the thixophilicity of the photosensitive resin composition, the stability (particularly storage stability) of the photosensitive resin composition is improved. Further, when the organic filler (E) contains a carboxyl group, it is possible to improve the developability of the cured product and improve the compatibility of the crystalline epoxy resin to prevent crystallization in the photosensitive resin composition. can. The carboxyl group content of the organic filler (E) is not particularly limited, but the acid value of the organic filler (E) is preferably 1 mgKOH / g or more and 60 mgKOH / g or less in terms of the acid value by acid-base titration. If the acid value is less than 1 mgKOH / g, the stability of the photosensitive resin composition and the developability of the cured product may deteriorate. If the acid value is larger than 60 mgKOH / g, the moisture resistance reliability of the cured product may decrease. The acid value of the organic filler (E) is more preferably 3 mgKOH / g or more and 40 mgKOH / g or less.

The organic filler (E) preferably has an average primary particle size of 1 μm or less. When the average primary particle size of the organic filler (E) is 1 μm or less, the developability of the photosensitive resin composition is improved. In addition, the roughness of the rough surface formed on the cured product can be made finer, and as the surface area of the cured product increases, the anchor effect increases and the adhesion between the rough surface and the plating layer can be improved. can.

The lower limit of the average primary particle size of the organic filler (E) is not particularly limited, but is preferably 0.001 μm or more, for example. The average primary particle size is measured as _D50 by a laser diffraction type particle size distribution measuring device. The average primary particle size of the organic filler (E1) is more preferably 0.4 μm or less, and further preferably 0.1 μm or less. In this case, it is possible to suppress light scattering in the photosensitive resin composition during exposure, thereby further improving the resolution of the photosensitive resin composition and having the interlayer insulating layer 7 having a small diameter portion 63. It becomes easy to form the via hole 6. In addition, the roughness of the rough surface formed on the cured product can be made particularly fine.

The organic filler (E) is preferably dispersed in the photosensitive resin composition with a maximum particle size of less than 1.0 μm, and more preferably less than 0.5 μm. The maximum particle size is measured as D ₅₀ by a laser diffraction type particle size distribution measuring device. Alternatively, the maximum particle size is measured by observing the cured product with a transmission electron microscope (TEM). The organic filler (E) may aggregate in the photosensitive resin composition (for example, it may form secondary particles), in which case the maximum particle size means the size of the particles after aggregation. When the maximum particle size of the organic filler (E) in the dispersed state is in the above range, scattering during exposure is suppressed in the photosensitive resin composition, whereby the resolution of the photosensitive resin composition is further improved. This is improved, and it becomes easier to form the via hole 6 having the small diameter portion 63 in the interlayer insulating layer 7. In addition, the roughness of the rough surface formed on the cured product can be further reduced. When particle aggregation occurs, the maximum particle size is usually larger than the average primary particle size.

The organic filler (E) preferably contains a rubber component. Further, the organic filler (E) preferably contains only a rubber component. The rubber component can impart flexibility to the cured product of the photosensitive resin composition. The rubber component may be composed of a resin. The rubber component preferably contains at least one polymer selected from crosslinked acrylic rubber, crosslinked NBR, crosslinked MBS and crosslinked SBR. In this case, the rubber component can impart excellent flexibility to the cured product of the photosensitive resin composition. Further, a more appropriate rough surface can be imparted to the surface of the cured product. Here, the rubber component includes a crosslinked structure formed when the monomers constituting the polymer are copolymerized. NBR is generally a copolymer of butadiene and acrylonitrile and is classified as nitrile rubber. MBS is generally a copolymer composed of three components of methyl methacrylate, butadiene, and styrene, and is classified as a butadiene rubber. SBR is generally a copolymer of styrene and butadiene and is classified as styrene rubber. Specific examples of the organic filler (E) include product number XER-91-MEK manufactured by JSR Corporation, product number XER-32-MEK manufactured by JSR Corporation, product number XSK-500 manufactured by JSR Corporation, and the like. XER-91-MEK is a crosslinked rubber (NBR) having a carboxyl group having an average primary particle diameter of 0.07 μm, and is provided with a methyl ethyl ketone dispersion having a content of 15% by weight of the crosslinked rubber, and has an acid value of 10. It is 0 mgKOH / g. XER-32-MEK is a dispersion liquid in which a polymer (linear particles) of a carboxyl group-modified hydrogenated nitrile rubber is dispersed in methyl ethyl ketone at a content of 17% by weight based on the total amount of the dispersion liquid. Further, XSK-500 is a crosslinked rubber (SBR) having a carboxyl group and a hydroxyl group having an average primary particle diameter of 0.07 μm, and is provided as a methyl ethyl ketone dispersion having a content of 15% by weight of the crosslinked rubber. As described above, the organic filler (E) is a dispersion liquid and may be blended in the photosensitive resin composition. That is, the rubber component is a dispersion liquid and can be blended in the photosensitive resin composition. In addition to the above, specific examples of the organic filler (E) include product number XER-92 manufactured by JSR Corporation.

The photosensitive resin composition can contain a silane coupling agent. In this case, the dispersibility of the organic filler (E) can be improved. Further, the resolution of the photosensitive resin composition can be improved.

The silane coupling agent is, for example, a compound containing a silicon atom and containing ₂ to 4 hydrolyzable groups selected from the group of ₃ groups of -OCH, ₅ groups of -OC 2H, and ₃ groups of -OCOCH. Is. In addition to the hydrolyzable group, the silane coupling agent may contain a reactive group such as an amino group, an epoxy group, a vinyl (allyl) group, a methacrylic group, a mercapto group, an isocyanate group or a sulfide group, or a methyl group. good.

Examples of the silane coupling agent include 3- (2-aminoethylamino) propyldimethoxymethylsilane, 3- (2-aminoethylamino) propyltriethoxysilane, and 3- (2-aminoethylamino) propyltrimethoxysilane. , 3-Aminopropyldiethoxymethylsilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane and other amino compounds, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, Epoxys such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidyloxypropyl (dimethoxy) methylsilane, diethoxy (3-glycidyloxypropyl) methylsilane, 3-acryloxypropyltrimethoxysilane, (Meta) acrylates such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyl Vinyl compounds such as triethoxysilane, p-styryltrimethoxysilane, diethoxymethylvinylsilane, vinyltris (2-methoxyethoxy) silane, allyl compounds such as allyltriethoxysilane and allyltrimethoxysilane, p-styryltrimethoxysilane, etc. Styryl compounds, isocyanates such as 3-isosyanatopropyltrimethoxysilane and 3-isosyanatopropyltriethoxysilane, ureidos such as 3-ureidopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane, (3-mercapto). Examples thereof include mercapto compounds such as propyl) triethoxysilane and (3-mercaptopropyl) trimethoxysilane, sulfides such as bis (triethoxysilylpropyl) tetrasulfide, tetraethyl orthosilicate, and methyltrimethoxysilane.

The photosensitive resin composition can contain melamine. In this case, the degree to which the cured product of the photosensitive resin composition is significantly corroded by, for example, an oxidizing agent containing potassium permanganate can be reduced. That is, since the photosensitive resin composition contains melamine, it is possible to make it difficult to reduce the thickness of the layer containing the cured product when the surface of the cured product of the photosensitive resin composition is roughened in the pre-plating step. .. By imparting a rough surface to the cured product in this way, it is possible to improve the adhesion between the cured product of the photosensitive resin composition and the plating layer made of copper, gold or the like. Melamine is 2,4,6-triamino-1,3,5-triazine and is available from commonly available compounds. The average particle size of melamine is 20 μm or less, preferably 15 μm or less, and it is preferable that the melamine is dispersed in the photosensitive resin composition. Since the melamine is uniformly dispersed in the photosensitive resin composition, the melamine is more easily coordinated and bonded to the metal element. This makes it possible to further improve the adhesion of the photosensitive resin composition. The lower limit of the average particle size of melamine is not particularly limited, but can be 0.01 μm or more. The average particle size of melamine is measured as D ₅₀ by a laser diffraction type particle size distribution measuring device in a state where melamine is dispersed in an uncured photosensitive resin composition.

The photosensitive resin composition may contain an inorganic filler. In this case, the curing shrinkage of the film formed from the photosensitive resin composition is reduced. In addition, the dielectric loss tangent can be reduced. The inorganic filler can contain one or more materials selected from the group consisting of, for example, barium sulfate, silica, carbon nanotubes, talc, bentonite, aluminum hydroxide, magnesium hydroxide, and titanium oxide.

The photosensitive resin composition according to this embodiment may contain an organic solvent. The organic solvent is used for the purpose of liquefaction or varnishing of the photosensitive resin composition, adjusting the viscosity, adjusting the coatability, adjusting the film-forming property, and the like.

Organic solvents include linear, branched, secondary or polyhydric alcohols such as ethanol, propyl alcohol, isopropyl alcohol, hexanol and ethylene glycol; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene. Kind; Petroleum-based aromatic mixed solvents such as Swazole series (manufactured by Maruzen Petrochemical Co., Ltd.) and Solbesso series (manufactured by Exxon Chemical Co., Ltd.); Thor; propylene glycol alkyl ethers such as propylene glycol methyl ether; polypropylene glycol alkyl ethers such as dipropylene glycol methyl ether; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, carbitol acetate; and dialkyl glycol ethers. It can contain one or more compounds selected from the group consisting of classes.

The carboxyl group-containing resin (A) is preferably in the range of 5% by mass or more and 85% by mass or less with respect to the solid content of the photosensitive resin composition, and is preferably in the range of 10% by mass or more and 75% by mass or less. It is more preferable, and more preferably in the range of 30% by mass or more and 60% by mass or less. The solid content is the total amount of all the components excluding the volatile components such as the solvent from the photosensitive resin composition.

The unsaturated compound (B) having at least one ethylenically unsaturated bond in one molecule is preferably in the range of 5% by mass or more and 45% by mass or less with respect to the carboxyl group-containing resin (A). When the unsaturated compound (B) is within this range, the via hole 6 having the small diameter portion 63 is particularly easy to be produced. The unsaturated compound (B) is more preferably in the range of 10% by mass or more and 42% by mass or less with respect to the carboxyl group-containing resin (A), and further preferably in the range of 21% by mass or more and 40% by mass or less. preferable.

The photopolymerization initiator (C) is preferably in the range of 1% by mass or more and 30% by mass or less with respect to the carboxyl group-containing resin (A). When the ratio of the photopolymerization initiator (C) is 1% by mass or more with respect to the carboxyl group-containing resin (A), the photosensitive resin composition tends to have good light absorption. When the photosensitive resin composition has good light absorption, the degree of curing of the surface of the interlayer insulating layer 7 can be easily increased, and the water absorption of the interlayer insulating layer 7 can be reduced. Further, it is easier to form the via hole 6 having the small diameter portion 63 in the interlayer insulating layer 7. When the photopolymerization initiator (C) is 30% by mass or less with respect to the carboxyl group-containing resin (A), the cured film of the photosensitive resin composition tends to have good electrical insulation.

The photopolymerization initiator (C) is more preferably in the range of 1.5% by mass or more and 25% by mass or less with respect to the carboxyl group-containing resin (A), and in the range of 2% by mass or more and 20% by mass or less. If it is, it is more preferable, and it is particularly preferable if it is in the range of 3% by mass or more and 10% by mass or less.

When the photosensitive resin composition contains the epoxy resin (D), the total equivalent of the epoxy groups contained in the epoxy resin (D) is 0 with respect to one equivalent of the carboxyl groups of the carboxyl group-containing resin (A). It is preferably 1 or more and 5 or less. When the epoxy group equivalent of the epoxy resin (D) is 0.1 or more with respect to the carboxyl group 1 equivalent of the carboxyl group-containing resin (A), the photosensitive resin composition is imparted with thermosetting property. Can be done. When the epoxy group equivalent of the epoxy resin (D) is 5 or less with respect to 1 equivalent of the carboxyl group of the carboxyl group-containing resin (A), the photosensitive resin composition has good developability. The epoxy group equivalent of the epoxy resin (D) is more preferably 0.3 or more and 4 or less, and 0.5 or more and 3 or less, with respect to 1 equivalent of the carboxyl group of the carboxyl group-containing resin (A). Is more preferable, and 0.7 or more and 2 or less is particularly preferable.

The content of the organic filler (E) is preferably 1% by mass or more and 100% by mass or less with respect to the carboxyl group-containing resin (A). When the content of the organic filler (E) is 1% by mass or more, the surface of the cured product of the photosensitive resin composition can be appropriately roughened, whereby the rough surface of the cured product and the plating layer can be obtained. Adhesion can be improved. When the content of the organic filler (E) is 100% by mass or less, the photosensitive resin composition tends to have good developability. The content of the organic filler (E) is more preferably 1.5% by mass or more and 50% by mass or less with respect to the carboxyl group-containing resin (A), and it is preferably 2% by mass or more and 30% by mass or less. It is more preferably 3% by mass or more and 20% by mass or less. In this case, the via hole 6 having the small diameter portion 63 is particularly easy to be formed.

When the photosensitive resin composition contains a silane coupling agent, the content of the silane coupling agent is preferably 0.01% by mass or more and 7% by mass or less with respect to the organic filler (E). When the ratio of the silane coupling agent is in this range, the organic filler (E) in the photosensitive resin composition is prevented from agglomerating and the dispersibility is improved. The ratio of the silane coupling agent is more preferably 0.05% by mass or more and 5% by mass or less with respect to the organic filler (E). When the ratio of the silane coupling agent is in this range, the aggregation of the organic filler (E1) in the photosensitive resin composition is prevented more efficiently, and the dispersibility is improved more effectively.

When the photosensitive resin composition contains melamine, the content of melamine is preferably 0.1% by mass or more and 10% by mass or less with respect to the carboxyl group-containing resin (A). In this case, it exhibits good developability with respect to an alkaline aqueous solution, and via holes 6 having a small diameter portion 63 are more likely to be formed in the interlayer insulating layer 7. The content of melamine is more preferably 0.3% by mass or more and 9% by mass or less, and further preferably 0.5% by mass or more and 8% by mass or less with respect to the carboxyl group-containing resin (A). It is particularly preferable that the content is 1% by mass or more and 6% by mass or less.

The ratio of the inorganic filler in the photosensitive resin composition is appropriately set, but the content of the inorganic filler is preferably 0% by mass or more and 200% by mass or less with respect to the carboxyl group-containing resin (A). In this case, good resolution is obtained, and the via hole 6 having the small diameter portion 63 is more likely to be formed in the interlayer insulating layer 7. The content of the inorganic filler is more preferably 0% by mass or more and 150% by mass or less, further preferably 0% by mass or more and 100% by mass or less, and 0% by mass with respect to the carboxyl group-containing resin (A). It is more preferably% or more and 50% by mass or less, and particularly preferably 0% by mass or more and 20% by mass or less.

When the photosensitive resin composition contains an organic solvent, the amount of the organic solvent is such that the organic solvent volatilizes rapidly when the coating film formed from the photosensitive resin composition is dried, that is, the organic solvent is dried. It is preferable to adjust so that it does not remain on the membrane. In particular, the proportion of the organic solvent with respect to the entire photosensitive resin composition is preferably 0% by mass or more and 99.5% by mass or less, and more preferably 15% by mass or more and 60% by mass or less. Since the suitable ratio of the organic solvent differs depending on the coating method and the like, it is preferable that the ratio is appropriately adjusted according to the coating method.

The photosensitive composition may further contain components other than the above components as long as the effects of the present embodiment are not impaired.

The photosensitive resin composition includes tolylene diisocyanate-based, morpholini diisocyanate-based, isophorone diisocyanate-based and hexamethylene diisocyanate-based blocked isocyanates blocked with caprolactam, oxime, malonic acid ester and the like; butylated urea resins; various other than the above. Thermo-curable resin; UV-curable epoxy (meth) acrylate; Resin obtained by adding (meth) acrylic acid to epoxy resins such as bisphenol A type, phenol novolac type, cresol novolak type, and alicyclic type; and diallyl phthalate. It may contain at least one resin selected from the group consisting of polymer compounds such as resins, phenoxy resins, urethane resins, melamine resins, and fluororesins.

The photosensitive resin composition may contain a curing agent for curing the epoxy compound (D). The curing agent is, for example, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- (2). -Imidazole derivatives such as -2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzylamine, Amine compounds such as 4-methyl-N, N-dimethylbenzylamine; hydrazine compounds such as adipic acid hydrazide and sevacinic acid hydrazide; phosphorus compounds such as triphenylphosphine; acid anhydrides; phenols; mercaptan; Lewis acid amine complex; And at least one component selected from the group consisting of onium salts. Commercially available products of these components include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (both are trade names of imidazole compounds) manufactured by Shikoku Kasei Co., Ltd., U-CAT3503N and UCAT3502T manufactured by San Apro Co., Ltd. (All are trade names of blocked isocyanate compounds of dimethylamine), DBU, DBN, U-CATSA102, U-CAT5002 (all are bicyclic amidine compounds and salts thereof).

The photosensitive resin composition may contain an adhesion-imparting agent. Examples of the adhesion-imparting agent include acetguanamine (2,4-diamino-6-methyl-1,3,5-triazine) and benzoguanamine (2,4-diamino-6-phenyl-1,3,5-triazine). ) And other guanamine derivatives, as well as 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-4,6-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine. Examples thereof include isocyanuric acid adducts, S-triazine derivatives such as 2,4-diamino-6-methacryloyloxyethyl-S-triazine and isocyanuric acid adducts, silane coupling agents, melamine derivatives and the like.

The photosensitive resin composition may contain a rheology control agent. The rheology control agent facilitates the viscosity of the photosensitive resin composition. Examples of the rheology control agent include urea-modified medium-polar polyamide (product number BYK-430 and BYK-431 manufactured by Big Chemie Japan Co., Ltd.), polyhydroxycarboxylic acid amide (product number BYK-405 manufactured by Big Chemie Japan Co., Ltd.), and the like. Modified urea (Part No. BYK-410, BYK-411, BYK-420 manufactured by Big Chemie Japan Co., Ltd.), Polymer urea derivative (Part number BYK-415 manufactured by Big Chemie Japan Co., Ltd.), Urea modified urethane (Part number BYK-415 manufactured by Big Chemie Japan Co., Ltd.) Company-manufactured product number BYK-425), polyurethane (part number BYK-428 manufactured by Big Chemie Japan Co., Ltd.), castor oil wax, polyethylene wax, polyamide wax, bentonite, kaolin, and clay.

The photosensitive resin composition is a curing accelerator; a colorant; a copolymer such as silicone or acrylate; a leveling agent; a thixotropic agent; a polymerization inhibitor; an antihalation agent; a flame retardant; an antifoaming agent; an antioxidant; a surfactant; Agents; as well as at least one component selected from the group consisting of polymer dispersants.

In preparing the photosensitive resin composition of the present embodiment, it may be adjusted by an appropriate method. For example, the photosensitive resin composition can be adjusted by mixing and stirring the raw materials of the photosensitive resin composition. Further, the photosensitive resin composition may be prepared by kneading by an appropriate kneading method using, for example, a three-roll, a ball mill, a sand mill or the like. When the raw material contains a liquid component, a low-viscosity component, etc., the portion of the raw material excluding the liquid component, the low-viscosity component, etc. is first kneaded to prepare a mixture, and then the obtained mixture is added. A photosensitive resin composition may be prepared by adding a liquid component, a component having a low viscosity, or the like and mixing them. When the photosensitive resin composition contains the solvent (E), a part or all of the solvent among the raw materials may be mixed first, and then mixed with the rest of the raw materials.

The photosensitive resin composition preferably has a property that even a film 4 having a thickness of 25 μm can be developed with an aqueous sodium carbonate solution. In this case, since a sufficiently thick electrically insulating layer can be produced from the photosensitive resin composition by a photolithography method, the photosensitive resin composition is produced and the interlayer insulating layer 7 in the printed wiring board 11 is produced. It is widely applicable to. Of course, it is also possible to prepare an electrically insulating layer having a thickness of less than 25 μm from the photosensitive resin composition.

Whether or not the film 4 having a thickness of 25 μm can be developed with an aqueous sodium carbonate solution can be confirmed by the following method. A wet coating film is prepared by applying a photosensitive resin composition on a suitable substrate 1, and the wet coating film is heated at 80 ° C. for 40 minutes to form a film 4 having a thickness of 25 μm. A negative mask having an exposed portion that transmits ultraviolet rays and a non-exposed portion that shields ultraviolet rays is directly applied to the film 4, and the film 4 is exposed to ultraviolet rays under the condition of 500 mJ / cm ² . After the exposure, a 1% Na ₂ CO ₃ aqueous solution at 30 ° C. is sprayed onto the film 4 at a jet pressure of 0.2 MPa for 90 seconds, and then pure water is sprayed at a jet pressure of 0.2 MPa for 90 seconds. As a result of observing the film 4 after this treatment, it can be determined that the film 4 having a thickness of 25 μm can be developed with an aqueous sodium carbonate solution when the portion corresponding to the unexposed portion of the film 4 is removed and no residue is observed. Similarly, it can be confirmed whether or not the film 4 having another thickness (for example, 30 μm) can be developed with an aqueous sodium carbonate solution.

(2.2) Manufacture of Printed Wiring Board 11 The manufacturing method of the printed wiring board 11 according to the present embodiment will be described in detail with reference to FIGS. 1A to 1E.

In manufacturing the printed wiring board 11, for example, a photosensitive resin composition and a substrate are prepared. The substrate has an insulating layer 2 and a second conductor layer 3 that overlaps the insulating layer 2. A film 4 made of a photosensitive resin composition is layered on a substrate so as to cover the second conductor layer 3, and a negative pattern-like region of the film 4 including the pattern of via holes 6 is exposed, and then alkaline. Development processing is performed using an aqueous solution. As a result, the interlayer insulating layer 7 and the via hole 6 penetrating the interlayer insulating layer 7 are produced.

Specifically, for example, first, as shown in FIG. 1A, the base material 1 is prepared. The base material 1 includes an insulating layer 2 and a second conductor layer 3. The second conductor layer 3 is a conductor wiring.

By applying the photosensitive resin composition on the substrate and further drying it if necessary, a film 4 covering the second conductor layer 3 is produced as shown in FIG. 1B. The method for applying the photosensitive resin composition is selected from the group consisting of known methods, for example, a dipping method, a spray method, a spin coating method, a roll coating method, a curtain coating method, and a screen printing method. When the photosensitive resin composition is dried, the photosensitive resin composition is heated at a temperature of, for example, 60 ° C. or higher and 130 ° C. or lower.

The film 4 may be formed by superimposing a dry film prepared from a photosensitive resin composition on a substrate. The dry film is formed on the support by applying the photosensitive resin composition on an appropriate support such as made of polyester and then drying the dry film. As a result, a dry film with a support including a dry film and a support for supporting the dry film can be obtained. The dry film in the dry film with a support is laminated on the base material 1 so as to cover the second conductor layer 3, and then pressure is applied to the dry film and the base material 1. As a result, the film 4 made of a dry film is superposed on the base material 1.

Next, the film 4 is exposed. For example, the negative pattern-like region of the film 4 including the pattern of the via holes 6 is exposed. In this case, for example, the film 4 is irradiated with ultraviolet rays via a negative mask. The negative mask includes an exposed portion that transmits ultraviolet rays and a non-exposed portion that shields ultraviolet rays, and the pattern of the non-exposed portion includes the pattern of the via hole 6. The negative mask is, for example, a photo tool such as a mask film or a dry plate. The ultraviolet light source is selected from the group consisting of, for example, a chemical lamp, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp and a metal halide lamp.

When the film 4 is made from a dry film, when the film 4 is exposed, for example, the support is peeled off from the film 4 in advance, and then the film 4 is exposed. The film 4 may be exposed by irradiating the film 4 with ultraviolet rays while the support is overlapped with the film 4, and then the support may be peeled off from the exposed film 4.

As the exposure method, a method other than the method using a negative mask may be adopted. For example, the film 4 may be exposed by a direct drawing method in which ultraviolet rays emitted from a light source are applied only to a portion of the film 4 to be exposed. The light sources applied to the direct drawing method are, for example, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, g-line (436 nm), h-line (405 nm), i-line (365 nm), and g-line, h-line, and i-line. It is selected from a group consisting of two or more combinations of.

The ultraviolet rays irradiating the film 4 preferably have spectral intensities at at least one wavelength in the wavelength range of 365 nm ± 65 nm. Further, it is preferable that the film 4 has no spectral intensity at a wavelength of 435 nm or more from the ultraviolet rays irradiating the film 4. Since the ultraviolet rays irradiating the film 4 have spectral intensities at at least one wavelength in the wavelength range of 365 nm ± 65 nm, the film 4 is easily cured. Further, when the ultraviolet rays include light having a wavelength of 435 nm or more, the diameter of the second end 62 of the via hole 6 formed in the interlayer insulating layer 7 tends to be small after development. It is presumed that the reason for this is that light having a long wavelength of 435 nm or more is not easily absorbed by the photosensitive resin composition, so that it easily reaches the deep part of the film 4, and light is likely to be scattered in the deep part of the film 4. The ultraviolet rays irradiating the film 4 have spectral intensity at at least one wavelength in the wavelength range of 365 nm ± 45 nm, and more preferably have no spectral intensity at 415 nm or higher, at least in the wavelength range of 365 nm ± 30 nm. It is even more preferable to have spectral intensity at one wavelength and no spectral intensity above 400 nm, with spectral intensity at at least one wavelength in the wavelength range of 365 nm ± 15 nm and spectral intensity above 385 nm. It is particularly preferable not to have it.

Next, the film 4 is developed with an alkaline aqueous solution to prepare an interlayer insulating layer 7 having via holes 6. At this time, as already described, the via hole 6 having the small diameter portion 63 is likely to be formed. By applying a developing treatment to the film 4, the uncured portion 5 of the film 4 shown in FIG. 1C is removed, thereby providing a via hole 6 as shown in FIG. 1D. In the developing process, an appropriate developer depending on the composition of the photosensitive resin composition can be used. The developer is, for example, an alkaline aqueous solution containing at least one of an alkali metal salt and an alkali metal hydroxide, or an organic amine. More specifically, the alkaline aqueous solution includes, for example, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, ammonium hydrogencarbonate, sodium hydroxide, potassium hydroxide, ammonium hydroxide, tetramethylammonium hydroxide and water. It contains at least one component selected from the group consisting of lithium oxide. The solvent in the alkaline aqueous solution may be water alone or a mixture of water and a hydrophilic organic solvent such as lower alcohols. The organic amine contains, for example, at least one component selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine and triisopropanolamine.

The alkaline aqueous solution preferably contains at least one of an alkali metal salt and an alkali metal hydroxide, and particularly preferably contains sodium carbonate. In this case, it is possible to improve the working environment and reduce the burden of waste disposal.

Since the photosensitive resin composition according to the present embodiment has good developability, the residue of the uncured photosensitive resin composition after development is unlikely to remain at the bottom of the via hole 6. Therefore, it is easy to form the via hole 6 having the small diameter portion 63.

Subsequently, the developed film 4 may be thermally cured by heating. The heating conditions are, for example, a heating temperature in the range of 120 ° C. or higher and 200 ° C. or lower, and a heating time in the range of 20 minutes or longer and 180 minutes or lower. When the film 4 is thermally cured in this way, the performance such as strength, hardness, and chemical resistance of the interlayer insulating layer 7 is improved.

If necessary, the film 4 may be further irradiated with ultraviolet rays before or after heating. In this case, the photocuring of the film 4 can be further promoted.

As described above, the interlayer insulating layer 7 made of a cured product of the photosensitive resin composition is provided on the base material 1. Subsequently, a first conductor layer 8 which is a conductor wiring can be made on the interlayer insulating layer 7 and a via conductor 9 can be made in the via hole 6 by a known method such as an additive method. As a result, as shown in FIG. 1E, a printed wiring board 11 having a first conductor layer 8, a second conductor layer 3, an interlayer insulating layer 7, a via hole 6 and a via conductor 9 is obtained. Although the via conductor 9 is filled in the entire via hole 6 in FIG. 1E, the via conductor 9 may be a film covering the inner surface of the via hole 6.

Further, before producing the via conductor 9, the entire inner surface of the via hole 6 and a part of the outer surface of the interlayer insulating layer 7 may be roughened. In this case, the adhesion between the base material 1 and the via conductor 9 can be improved.

Roughening of a part of the outer surface of the interlayer insulating layer 7 and the entire inner surface of the via hole 6 can be performed by the same procedure as the general desmear treatment using an oxidizing agent. For example, an oxidizing agent is brought into contact with the outer surface of the interlayer insulating layer 7 to roughen the outer surface of the interlayer insulating layer 7. However, the present invention is not limited to this, and an appropriate roughening method such as plasma treatment, UV treatment, ozone treatment, or the like may be adopted.

The oxidant may be an oxidant available as a desmear solution. Such an oxidizing agent can contain, for example, at least one permanganate selected from the group of sodium permanganate and potassium permanganate.

In providing the via conductor 9, the initial conductor can be formed by subjecting a part of the roughened outer surface and the inner surface of the via hole 6 to electroless metal plating. After that, the via conductor 9 can be formed by precipitating the metal in the electrolytic plating solution on the initial conductor by the electrolytic metal plating treatment.

Hereinafter, the present disclosure will be specifically described with reference to Examples. However, the present disclosure is not limited to the following examples, and various changes can be made according to the design as long as the object of the present disclosure can be achieved.

1. 1. Synthesis of Carboxyl Group-Containing Resin [Synthesis Examples 1 to 6: Bisphenol Fluorene Skeleton-Containing Resin]
In a four-necked flask equipped with a reflux condenser, a thermometer, an air blow tube and a stirrer, the components shown in the "First reaction" column in Table 1 are added, and these are stirred under air bubbling to form a mixture. Was prepared. The mixture was heated in a flask at the reaction temperature and reaction time shown in the "Reaction Conditions" column with stirring under air bubbling. This prepared a solution of the intermediate.

Subsequently, the components shown in the "second reaction" column of Table 1 are added to the solution of the intermediate in the flask, and the reaction temperature and reaction time shown in the "reaction condition (1)" column are stirred while stirring under air bubbling. Heated in. Subsequently, the mixture was heated at the reaction temperature and reaction time shown in the “Reaction condition (2)” column while stirring under air bubbling. As a result, a 65% by mass solution of the carboxyl group-containing resin was obtained. The weight average molecular weight and acid value of the carboxyl group-containing resin are as shown in Table 1.

The details of the components shown in the column (a1) in Table 1 are as follows.
Epoxy compound 1: A bisphenol fluorene-type epoxy compound having an epoxy equivalent of 250 g / eq, which is represented by the formula (2) and in which R ₁ to R ₈ in the formula (2) are all hydrogen.
Epoxy compound 2: Epoxy equivalent 279 g represented by the formula (2), in which R ₁ and R ₅ in the formula (2) are all methyl groups, and R ₂ to R ₄ and R ₆ to R ₈ are all hydrogen. / Eq bisphenol fluorene type epoxy compound.

[Synthesis Example 7: Biphenyl Novolac Skeleton-Containing Resin]
Biphenyl novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., product number NC-3000-H, epoxy equivalent 288 g / eq) 288 mass in a four-necked flask equipped with a reflux cooler, a thermometer, an air blow tube and a stirrer. , 155 parts by mass of diethylene glycol monoethyl ether acetate, 0.2 parts by mass of methylhydroquinone, 72 parts by mass of acrylic acid, and 3 parts by mass of triphenylphosphine were added to prepare a mixture. The mixture was heated in a flask at a temperature of 115 ° C. for 12 hours with stirring under air bubbling. This prepared a solution of the intermediate.

Subsequently, 85 parts by mass of tetrahydrophthalic anhydride and 86.3 parts by mass of diethylene glycol monoethyl ether acetate were added to the solution of the intermediate in the flask, and the mixture was heated at 90 ° C. for 4 hours while stirring under air bubbling. .. As a result, a 65% by mass solution of the carboxyl group-containing resin B-1 was obtained. The weight average molecular weight of the carboxyl group-containing resin B-1 was 8026, and the acid value was 69 mgKOH / g.

2. 2. Preparation of Composition The components shown in Tables 2 to 3 below were kneaded with three rolls and then stirred and mixed in a flask to obtain a composition. The details of the components shown in Tables 2 to 3 are as follows.
-Unsaturated compound A: Trimethylolpropane triacrylate.
-Photopolymerization initiator A: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, manufactured by BASF, product number Irgacure TPO.
-Photopolymerization initiator B: 1-hydroxy-cyclohexyl-phenyl-ketone, manufactured by BASF, product number Irgacure 184.
-Photopolymerization initiator C: 4,4'-bis (diethylamino) benzophenone.
-Photopolymerization initiator D: 2,4-diethylthioxanthene-9-one.
Crystalline epoxy resin A: Bisphenol type crystalline epoxy resin, product number YSLV-80XY manufactured by Nittetsu Chemical & Materials Co., Ltd., melting point 75-85 ° C., epoxy equivalent 192 g / eq.
Acrystalline epoxy resin solution A: Long-chain carbon chain-containing bisphenol A type epoxy resin, manufactured by DIC Corporation, product number EPICLON EXA-4816, liquid resin, epoxy equivalent 410 g / eq to diethylene glycol monoethyl acetate with 90% solid content Dissolved solution.
-Organic filler A dispersion: A dispersion in which crosslinked rubber (NBR) having an average primary particle diameter of 0.07 μm is dispersed in methyl ethyl ketone at a content of 15% by weight based on the total amount of the dispersion (manufactured by JSR Corporation, product number). XER-91-MEK; acid value 10.0 mgKOH / g).
-Organic filler B: A glycidyl-modified acrylonitrile butadiene rubber having an average primary particle diameter of 0.3 μm.
-Additive A: 3-glycidoxypropyltrimethoxysilane.
-Additive B: Melamine.
-Solvent A: Methyl ethyl ketone.

3. 3. Evaluation of composition (1) Preparation of test piece A test piece was prepared as follows using the composition of each composition example.

The composition of each composition example is applied on a film made of polyethylene terephthalate with an applicator, heated at 80 ° C. for 5 minutes, and then heated at 95 ° C. for 20 minutes to be dried to obtain a thickness on the film. A 35 μm dry film was formed.

A glass epoxy copper-clad laminate (FR-4 type) provided with a copper foil having a thickness of 17.5 μm was prepared. The surface portion of this glass epoxy copper-clad laminate having a thickness of about 1 μm was roughened by treating with an etching agent (product number CZ-8101 manufactured by MEC COMPANY Ltd.). The above dry film was heat-laminated with a vacuum laminator on the entire surface of the glass epoxy copper-clad laminate. The conditions for heat laminating were set at 0.5 MPa, 80 ° C., and 1 minute. As a result, a film made of the above-mentioned dry film was formed on the glass epoxy copper-clad laminate. This film was irradiated with ultraviolet rays having a wavelength of 365 nm under the condition of an integrated light amount of 250 mJ / cm ² via a negative mask having a non-exposed portion having a pattern including a circular shape having a diameter of 80 μm and a film made of polyethylene terephthalate. Subsequently, the polyethylene terephthalate film was peeled off from the film.

Subsequently, an alkaline aqueous solution (1% Na ₂ CO ₃ aqueous solution) at 30 ° C. was injected onto the film at an injection pressure of 0.2 MPa for 90 seconds, and then pure water was injected at an injection pressure of 0.2 MPa for 90 seconds. , The film was developed. Subsequently, the film was heated at 180 ° C. for 120 minutes. As a result, an interlayer insulating layer and via holes penetrating the interlayer insulating layer were formed on the printed wiring board. This gave a test piece.

The following evaluation was performed on this test piece. In Composition Example 11, development was not possible and evaluation was not performed. Further, in Composition Example 14, the film was not evaluated because there was a part where peeling of the film was observed due to insufficient curing during development.

(2) Measurement of the diameter of the first end and the diameter of the second end The test piece is cut so as to cut the via hole on a plane parallel to the axis of the via hole, and the cross section is photographed using an electron microscope (SEM). bottom. From the image obtained thereby, the diameter of the first end and the diameter of the second end of the via hole were measured. Further, the value of (diameter of the first end ÷ diameter of the second end) × 100 (%) was obtained.

(3) Presence or absence of small diameter portion From the image obtained in the above "(2) Measurement of the diameter of the first end and the diameter of the second end", the small diameter portion is located between the first end and the second end of the via hole. Was confirmed to exist and evaluated as follows.
A: There is a small diameter portion between the first end and the second end, and the minimum diameter of the small diameter portion is 65% or more and less than 100% with respect to the diameter of the second end.
B: There is a small diameter portion between the first end and the second end, and the minimum diameter of the small diameter portion is less than 65% of the diameter of the second end.
C: There is no small diameter portion between the first end and the second end.

(4) Via shape evaluation The shape of the via hole was evaluated as follows from the image obtained in the above "(2) Measurement of the diameter of the first end and the diameter of the second end".
A: The value of (diameter of the first end ÷ diameter of the second end) × 100 (%) is 80% or more, and between the first end and the second end with respect to the diameter of the second end. There is a small diameter portion of 65% or more and less than 100%.
B: The value of (diameter of the first end ÷ diameter of the second end) × 100 (%) is 75% or more and less than 80%, and between the first end and the second end, the second end There is a small diameter portion of 65% or more and less than 100% with respect to the diameter.
C: The value of (diameter of the first end ÷ diameter of the second end) × 100 (%) is 65% or more and less than 75%, and between the first end and the second end, the second end There is a small diameter portion of 65% or more and less than 100% with respect to the diameter.
D: The value of (diameter of the first end ÷ diameter of the second end) × 100 (%) is less than 65%, and a small diameter portion exists between the first end and the second end.
E: There is no small diameter part.

The results of the above evaluation tests are shown in Tables 2 and 3 below.

4. Evaluation of printed wiring board (1) Preparation of test piece The film formation method and film thickness during film formation, the diameter of the circular pattern during exposure, the wavelength and integrated light intensity of ultraviolet rays, and the injection of an alkaline aqueous solution during development. A test piece was prepared by the method described in "(1) Preparation of test piece" in "1. Evaluation of composition" above, except that the time was set as shown in Tables 4 to 6. When a plurality of numerical values are described in the wavelength column, ultraviolet rays having a wavelength of each numerical value were simultaneously irradiated.

The following evaluation was performed on this test piece. In Comparative Example 1, development was not possible and evaluation was not performed. Further, in Comparative Example 3, the film was not evaluated because there was a part where peeling of the film was observed due to insufficient curing during development.

(2) Measurement of the diameter of the first end and the diameter of the second end The test piece was cut so as to cut the via hole at a plane parallel to the axis of the via hole, and the cross section was observed with an electron microscope (SEM). From the image obtained thereby, the diameter of the first end and the diameter of the second end of the via hole were measured. Further, the value of (diameter of the first end ÷ diameter of the second end) × 100 (%) was obtained.

(3) Presence or absence of small diameter portion From the image obtained in the above "(2) Measurement of the diameter of the first end and the diameter of the second end", the small diameter portion is located between the first end and the second end of the via hole. Was confirmed to exist and evaluated as follows.
A: There is a small diameter portion between the first end and the second end, and the minimum diameter of the small diameter portion is 65% or more and less than 100% with respect to the diameter of the second end.
B: There is a small diameter portion between the first end and the second end, and the minimum diameter of the small diameter portion is less than 65% of the diameter of the second end.
C: There is no small diameter portion between the first end and the second end.

(4) Via shape evaluation The shape of the via hole was evaluated as follows from the image obtained in the above "(2) Measurement of the diameter of the first end and the diameter of the second end".
A: The value of (diameter of the first end ÷ diameter of the second end) × 100 (%) is 80% or more, and between the first end and the second end with respect to the diameter of the second end. There is a small diameter portion of 65% or more and less than 100%.
B: The value of (diameter of the first end ÷ diameter of the second end) × 100 (%) is 75% or more and less than 80%, and between the first end and the second end, the second end There is a small diameter portion of 65% or more and less than 100% with respect to the diameter.
C: The value of (diameter of the first end ÷ diameter of the second end) × 100 (%) is 65% or more and less than 75%, and between the first end and the second end, the second end There is a small diameter portion of 65% or more and less than 100% with respect to the diameter.
D: The value of (diameter of the first end ÷ diameter of the second end) × 100 (%) is less than 65%, and a small diameter portion exists between the first end and the second end.
E: There is no small diameter part.

(5) Via connection reliability The test piece was roughened on the outer surface of the interlayer insulating layer by the following desmear treatment, which is common as a pre-plating step.

The interlayer insulating layer is swelled with a swelling solution for Desmia (Swelling Dip Security Guns P manufactured by Atotech Japan Co., Ltd.) at 70 ° C. for 10 minutes to swell the surface of the interlayer insulating layer. The interlayer insulating layer was washed with hot water. Subsequently, the surface of the interlayer insulating layer was roughened by treating it with a desmear solution (an oxidizing agent containing potassium permanganate. Concentrate Compact CP manufactured by Atotech Japan Co., Ltd.) at 70 ° C. for 10 minutes. Then, the interlayer insulating layer was washed with hot water. Next, the surface of the interlayer insulating layer is treated with a neutralizing solution (Reduction Solution Securigant P manufactured by Atotech Japan Co., Ltd.) at 40 ° C. for 5 minutes to remove the residue, and then the interlayer insulating layer is washed with water. bottom.

Next, an electroless copper plating treatment was applied to the interlayer insulating layer to prepare an initial conductor, and then the conductor was heated at 150 ° C. for 1 hour. Next, the initial conductor was subjected to electrolytic copper plating under the condition of a current density of 2 A / dm ² , and then heated at 180 ° C. for 30 minutes. As a result, a first conductor layer having a thickness of 33 μm was formed on the interlayer insulating layer, and a via conductor was formed in the via hole.

Next, a temperature cycle test was carried out in which the test piece was exposed to the condition of −55 ° C. for 15 minutes and then exposed to the condition of 125 ° C. for 15 minutes for 500 cycles. The electric resistance value between the first conductor layer and the second conductor layer through the via conductor before and after the test was measured, and the rate of change was evaluated as follows.
A: The rate of change in resistance before and after the temperature cycle test is less than 8%.
B: The rate of change in resistance before and after the temperature cycle test is 8% or more and less than 10%.
C: The rate of change in resistance before and after the temperature cycle test is 10% or more.

The results of the above evaluation tests are shown in Tables 4 to 6 below.

3 Second conductor layer 4 Film 6 Via hole 61 First end 62 Second end 63 Small diameter part 7 Interlayer insulation layer 8 First conductor layer 9 Via conductor

Claims (19)

An interlayer insulating layer interposed between the first conductor layer, the second conductor layer, the first conductor layer and the second conductor layer, a via hole penetrating the interlayer insulating layer, and a via hole in the via hole. It is provided with a via conductor that is arranged and conducts the first conductor layer and the second conductor layer.
The interlayer insulating layer is a negative type containing a carboxyl group-containing resin (A), an unsaturated compound (B) having at least one ethylenically unsaturated bond in one molecule, and a photopolymerization initiator (C). Is a cured product of the photosensitive resin composition of
The via hole is located between the first end, which is the end on the first conductor layer side, the second end, which is the end on the second conductor layer side, and the first end and the second end. With a small diameter portion having a diameter smaller than the diameter of the second end,
Printed wiring board. The minimum diameter of the small diameter portion is 65% or more and less than 100% of the diameter of the second end.
The printed wiring board according to claim 1. The diameter of the first end is 65% or more with respect to the diameter of the second end.
The printed wiring board according to claim 1 or 2. The diameter of the first end is 100 μm or less.
The printed wiring board according to any one of claims 1 to 3. The carboxyl group-containing resin (A) contains a carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton.
The printed wiring board according to any one of claims 1 to 4. The weight average molecular weight of the carboxyl group-containing resin (A) is 700 or more and 100,000 or less.
The printed wiring board according to any one of claims 1 to 5. The carboxyl group-containing resin (A) contains a component having an acid value of 65 mgKOH / g or more and 150 mgKOH / g or less.
The printed wiring board according to any one of claims 1 to 6. The percentage of the unsaturated compound (B) is 5% by mass or more and 45% by mass or less with respect to the carboxyl group-containing resin (A).
The printed wiring board according to any one of claims 1 to 7. The percentage of the photopolymerization initiator (C) is 1% by mass or more and 30% by mass or less with respect to the carboxyl group-containing resin (A).
The printed wiring board according to any one of claims 1 to 8. The photopolymerization initiator (C) contains at least one selected from the group consisting of an acylphosphine oxide-based photopolymerization initiator, an α-aminoalkylphenone-based photopolymerization initiator, and an oxime ester-based photopolymerization initiator. ,
The printed wiring board according to any one of claims 1 to 9. The above further contains a photosensitive resin composition and an epoxy resin (D).
The printed wiring board according to any one of claims 1 to 10. The equivalent of the epoxy group of the epoxy resin (D) is 0.1 or more and 5 or less with respect to one equivalent of the carboxyl group of the carboxyl group-containing resin (A).
The printed wiring board according to claim 11. The photosensitive resin composition further contains the organic filler (E).
The printed wiring board according to any one of claims 1 to 12. The organic filler (E) has a reactive group.
The printed wiring board according to claim 13. The reactive group comprises at least one group selected from the group consisting of a carboxyl group, an amino group, an epoxy group, a vinyl group, and a hydroxyl group.
The printed wiring board according to claim 14. The ratio of the organic filler (E) to the carboxyl group-containing resin (A) is 1% by mass or more and 100% by mass or less.
The printed wiring board according to any one of claims 13 to 15. The method for manufacturing the printed wiring board according to any one of claims 1 to 16.
The negative type photosensitive resin containing the carboxyl group-containing resin (A), the unsaturated compound (B) having at least one ethylenically unsaturated bond in one molecule, and the photopolymerization initiator (C). A substrate having the composition and the insulating layer and the second conductor layer overlapping the insulating layer is prepared.
A film made from the photosensitive resin composition was layered on the substrate so as to cover the second conductor layer.
By exposing the negative pattern-like region of the film including the pattern of the via holes and then developing the film with an alkaline aqueous solution, the interlayer insulating layer and the via holes penetrating the interlayer insulating layer are applied. Including making and
Manufacturing method of printed wiring board. The present invention comprises superimposing a dry film made from the photosensitive resin composition on the substrate to form the film.
The method for manufacturing a printed wiring board according to claim 17. Upon exposing the film, the film is irradiated with light having a spectral intensity at at least one wavelength in the wavelength range of 365 nm ± 65 nm and having no spectral intensity at a wavelength of 435 nm or more.
The method for manufacturing a printed wiring board according to claim 17 or 18.

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