CN112210333B - Photosensitive adhesive composition, dry film, and method for producing multilayer substrate - Google Patents

Abstract

The invention provides a photosensitive adhesive composition capable of realizing high bonding strength when a first component and a second component are bonded. The photosensitive adhesive composition contains: a carboxyl group-containing resin (A), a photopolymerization initiator (B) and a photopolymerizable compound (C). The photosensitive adhesive composition is used for manufacturing a first adhesive layer (11) and a second adhesive layer (12) on a first component (1) and a second component (2), respectively, and bonding the first adhesive layer (11) and the second adhesive layer (12) by overlapping and bonding, thereby bonding the first component (1) and the second component (2) through the first adhesive layer (11) and the second adhesive layer (12).

Description

Photosensitive adhesive composition, dry film, and method for producing multilayer substrate

Technical Field

The present invention relates to a photosensitive adhesive composition, a dry film containing the photosensitive adhesive composition, and a method for producing a multilayer substrate having a layer containing a cured product of the photosensitive adhesive composition.

Background

With the demand for higher performance of electronic devices, printed wiring boards have been multilayered. One of the methods for forming a printed wiring board into a multilayer is a method in which two members are bonded via an adhesive.

For example, patent document 1 discloses a photosensitive composition having adhesion even after a photo-curing reaction and after patterning, and discloses a technique for adhering substrates to each other using the photosensitive adhesive composition.

Prior art literature

Patent literature

Patent document 1: international publication No. 2011/071107

Disclosure of Invention

However, although the photosensitive adhesive composition of patent document 1 can bond members such as glass substrates to each other, it is difficult to say that sufficient bonding strength is necessarily obtained.

The purpose of the present invention is to provide a photosensitive adhesive composition, a dry film, and a method for producing a multilayer substrate, wherein high bonding strength can be achieved when two members are bonded.

The photosensitive adhesive composition according to one embodiment of the present invention comprises: a carboxyl group-containing resin (A), a photopolymerization initiator (B) and a photopolymerizable compound (C). The photosensitive adhesive composition is used for producing a first adhesive layer and a second adhesive layer on a first member and a second member, respectively, and bonding the first member and the second member via the first adhesive layer and the second adhesive layer by superposing and bonding the first adhesive layer and the second adhesive layer.

The dry film according to one embodiment of the present invention contains a dried product of the photosensitive adhesive composition.

In the method for manufacturing a multilayer substrate according to one aspect of the present invention, a first adhesive layer and a second adhesive layer are formed on a first member and a second member, respectively, from the photosensitive adhesive composition or the dry film, and the first member and the second member are bonded together through the first adhesive layer and the second adhesive layer by overlapping and bonding the first adhesive layer and the second adhesive layer.

According to the photosensitive adhesive composition and the dry film of one embodiment of the present invention, a high bonding strength can be achieved when the first member and the second member are bonded.

According to the method for manufacturing a multilayer substrate of one embodiment of the present invention, a multilayer substrate having high bonding strength between members can be obtained.

Drawings

Fig. 1 is a cross-sectional view schematically showing a multilayer substrate according to an embodiment of the present invention.

Fig. 2A to 2E are cross-sectional views showing an example (first example) of a process for manufacturing a multilayer substrate according to an embodiment of the present invention.

Fig. 3A to 3F are cross-sectional views showing another example (second example) of the process of manufacturing a multilayer substrate.

Symbol description

1. First part

2. Second part

10. Multilayer substrate

11. First adhesive layer

12. A second adhesive layer

Detailed Description

The mode for carrying out the present invention will be described below. In the following description, "(meth) acrylic acid" means at least one of "acrylic acid" and "methacrylic acid". For example, (meth) acrylate refers to at least one of acrylate and methacrylate.

The photosensitive adhesive composition of the present embodiment contains: a carboxyl group-containing resin (A), a photopolymerization initiator (B) and a photopolymerizable compound (C). The photosensitive adhesive composition is used to produce the first adhesive layer 11 and the second adhesive layer 12 on the first member 1 and the second member 2, respectively, and the first adhesive layer 11 and the second adhesive layer 12 are overlapped and bonded to join the first member 1 and the second member 2 via the first adhesive layer 11 and the second adhesive layer 12.

According to the present embodiment, as described above, by producing the first adhesive layer 11 and the second adhesive layer 12 from the photosensitive adhesive composition, the first member 1 and the second member 2 are bonded via the first adhesive layer 11 and the second adhesive layer 12, and thus high bonding strength between the first member 1 and the second member 2 is easily achieved. In the following, when the first adhesive layer 11 and the second adhesive layer 12 are overlapped to join the first member 1 and the second member 2, a layer formed of the first adhesive layer 11 and the second adhesive layer 12 interposed between the first member 1 and the second member 2 is also referred to as a joining layer 13. At least one of the first member 1 and the second member 2 may be a printed wiring board including an insulating layer and a conductor wiring superimposed on the insulating layer, or may be a metal-clad laminate including a support base made of a resin material or the like and a metal foil such as a copper foil superimposed on the support base. More specific examples of the first member 1 and the second member 2 are described below.

In particular, the photosensitive adhesive composition of the present embodiment can achieve high bonding strength between the first member 1 and the second member 2 even when the first adhesive layer 11 and the second adhesive layer 12 formed on the first member 1 and the second member 2, respectively, are exposed to light such as ultraviolet rays and cured by exposure to light, and then the first member 1 and the second member 2 are bonded via the first adhesive layer 11 and the second adhesive layer 12.

In the present embodiment, the photosensitive resin composition may be exposed to light and then developed with an alkaline solution or the like. Therefore, with the photosensitive adhesive composition of the present embodiment, an appropriate pattern can be provided to the first adhesive layer 11 and the second adhesive layer 12 by photolithography. At this time, the first member 1 and the second member 2 can be bonded via the first adhesive layer 11 and the second adhesive layer 12 having appropriate patterns, and high bonding strength can be achieved. Therefore, the bonding layer 13 having a high-definition pattern can be produced using the photosensitive adhesive composition.

The reason why the first adhesive layer 11 and the second adhesive layer 12 formed of the photosensitive adhesive composition of the present embodiment have high adhesion and can impart high bonding strength when the first member 1 and the second member 2 are bonded is not clear, but the following reason is presumed.

This is considered to be because if the photosensitive adhesive composition contains the carboxyl group-containing resin (a), the photopolymerization initiator (B) and the photopolymerizable compound (C), the adhesive layers can be bonded to each other in a state where the adhesive layers are cured by irradiation of light such as ultraviolet rays and the first member 1 and the first adhesive layer 11 and the second member 2 and the second adhesive layer 12 are firmly adhered to each other. Further, it is considered that the first adhesive layer 11 and the second adhesive layer 12 formed of the photosensitive adhesive composition can be bonded to each other with a strong adhesion strength even in a state where they are photo-cured.

Even if the photosensitive adhesive composition of the present embodiment has several tens of layers of the first member 1 and the second member 2, for example, a substrate in which the first member 1 and the second member 2 are alternately laminated with 10 layers, the first adhesive layer 11 and the second adhesive layer 12 may be formed on the first member 1 and the second member 2, respectively, and the first adhesive layer 11 and the second adhesive layer 12 may be bonded to each other to form the bonding layer 13. Thus, for example, a multilayer substrate having 20 or more layers can be produced. Therefore, the photosensitive adhesive composition of the present embodiment can be suitably used for bonding a plurality of layers of substrates to each other to produce a substrate having a larger number of layers.

The components that can be contained in the photosensitive adhesive composition according to the present embodiment will be described in detail.

The carboxyl group-containing resin (A) has carboxyl groups. The carboxyl group-containing resin (A) preferably has an ethylenically unsaturated group. The carboxyl group-containing resin (a) has an ethylenically unsaturated group, and thus the photosensitive adhesive composition containing the carboxyl group-containing resin (a) has photoreactivity. Therefore, the carboxyl group-containing resin (a) can impart photosensitivity, specifically, ultraviolet curability, to the photosensitive adhesive composition.

The carboxyl group-containing resin (a) preferably contains a carboxyl group-containing resin having an aromatic ring. The carboxyl group-containing resin (a) can impart high heat resistance and insulation reliability to a cured product of the photosensitive adhesive composition containing the carboxyl group-containing resin (a) by containing an aromatic ring. The carboxyl group-containing resin (a) more preferably contains a carboxyl group-containing resin having any one polycyclic aromatic ring of a biphenyl skeleton, a naphthalene skeleton, a fluorene skeleton, and an anthracene skeleton. The carboxyl group-containing resin (a) can impart higher heat resistance and insulation reliability to a cured product of the photosensitive adhesive composition containing the carboxyl group-containing resin (a) by containing any one of polycyclic aromatic rings of a biphenyl skeleton, a naphthalene skeleton, a fluorene skeleton, and an anthracene skeleton. The carboxyl group-containing resin (a) further preferably contains a carboxyl group-containing resin having a bisphenol fluorene skeleton. The carboxyl group-containing resin (a) can impart higher heat resistance and insulation reliability to a cured product of the photosensitive adhesive composition containing the carboxyl group-containing resin (a) by containing a bisphenol fluorene skeleton.

The carboxyl group-containing resin (a) preferably contains a carboxyl group-containing resin (A1) having a bisphenol fluorene skeleton, which will be described below. The carboxyl group-containing resin (A1) is, for example, a reactant of an intermediate compound (A1) having a bisphenol fluorene skeleton represented by the following formula (1) and a carboxylic acid (a 2), and an acid anhydride (a 3), and the carboxylic acid (a 2) includes a carboxylic acid (a 2-1) having an unsaturated group. In formula (1), R ₁ ～R ₈ Each independently represents hydrogen, an alkyl group having 1 to 5 carbon atoms, or halogen. The carboxyl group-containing resin (A1) is synthesized by: an epoxy compound (a 1) having a bisphenol fluorene skeleton (S1) represented by the following formula (1) is reacted with a carboxylic acid (a 2) comprising a carboxylic acid (a 2-1) having an unsaturated group, and the intermediate thus obtained is reacted with an acid anhydride (a 3).

In the formula (1), R ₁ ～R ₈ Each independently represents hydrogen, an alkyl group having 1 to 5 carbon atoms, or halogen. Namely, R in formula (1) ₁ ～R ₈ Each may be hydrogen, or an alkyl group having 1 to 5 carbon atoms or halogen. This is because, even if the 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 the heat resistance or flame retardancy of the cured product of the photosensitive adhesive composition containing the carboxyl group-containing resin (A1) may be improved.

When the carboxyl group-containing resin (A1) has a bisphenol fluorene skeleton represented by formula (1), the carboxyl group-containing resin (A1) preferably has at least one alkyl group. In this case, the dielectric loss tangent of the cured product layer containing the cured product of the photosensitive adhesive composition can be further reduced. For example, R in formula (1) ₁ ～R ₈ At least one of (2) is preferably an alkyl group having 1 to 5 carbon atoms.

The carboxyl group-containing resin (A1) has a bisphenol fluorene skeleton represented by formula (1) derived from the epoxy compound (A1), and can impart high heat resistance and insulation reliability to a cured product of the photosensitive adhesive composition. Further, the carboxyl group-containing resin (A1) has a carboxyl group derived from the acid anhydride (a 3), and thus can impart excellent developability to the photosensitive adhesive composition. Further, the photosensitive adhesive composition can be provided with thermosetting properties by containing an epoxy resin.

The carboxyl group-containing resin (A1) can be synthesized, for example, as described below. In order to synthesize the carboxyl group-containing resin (A1), at least a part of the epoxy group (see formula (2)) of the epoxy compound (A1) is first reacted with the carboxylic acid (a 2) containing the unsaturated group-containing carboxylic acid (a 2-1), to synthesize an intermediate. The synthesis of the intermediate is defined as the first reaction. The intermediate has a structure (S3) represented by the following formula (3) which is produced by a ring-opening addition reaction of an epoxy group with a carboxylic acid (a 2). That is, the intermediate has a secondary hydroxyl group in the structure (S3) generated by the ring-opening addition reaction of the epoxy group and the carboxylic acid (a 2). In formula (3), A is a carboxylic acid residue. The a comprises a carboxylic acid residue comprising an unsaturated group.

Next, the secondary hydroxyl group in the intermediate is reacted with an acid anhydride (a 3). Thus, the carboxyl group-containing resin (A1) can be synthesized. The reaction of the intermediate with the acid anhydride (a 3) is defined as the second reaction. The acid anhydride (a 3) may comprise an acid monoanhydride and an acid dianhydride. The acid monoanhydride is a compound having one acid anhydride group, which is obtained by dehydration-condensation of two carboxyl groups in one molecule. The acid dianhydride is a compound having two acid anhydride groups, which is obtained by dehydration-condensation of four carboxyl groups in one molecule.

The acid anhydride (a 3) may contain at least 1 of an acid dianhydride (a 3-2) and an acid monoanhydride (a 3-1). When the acid anhydride (a 3) contains the acid monoanhydride (a 3-1), the carboxyl group-containing resin (A1) has a bisphenol fluorene skeleton (S1) represented by the formula (1) and a structure (S4) represented by the following formula (4).

Structure (S4) is produced by reacting the secondary hydroxyl group in structure (S3) of the intermediate with the anhydride group in the acid monoanhydride (a 3-1). In formula (4), A is a carboxylic acid residue and B is an acid monoanhydride residue. The a comprises a carboxylic acid residue comprising an unsaturated group.

When the acid anhydride (a 3) contains the acid dianhydride (a 3-2), the carboxyl group-containing resin (A1) has a bisphenol fluorene skeleton (S1) represented by the formula (1) and a structure (S5) represented by the following formula (5).

Structure (S5) is produced by the reaction of two anhydride groups in the acid dianhydride (a 3-2) with two secondary hydroxyl groups in the intermediate, respectively. That is, the structure (S5) is produced by crosslinking two secondary hydroxyl groups with each other by the acid dianhydride (a 3-2). It should be noted that there may be a case where two secondary hydroxyl groups present in one molecule of the intermediate are crosslinked with each other and a case where two secondary hydroxyl groups respectively present in two molecules of the intermediate are crosslinked with each other. If two secondary hydroxyl groups respectively present in two molecules of the intermediate are crosslinked with each other, the molecular weight increases. In formula (5), A is a carboxylic acid residue and D is an acid dianhydride residue. The a comprises a carboxylic acid residue comprising an unsaturated group.

The carboxyl group-containing resin (A1) can be obtained by reacting the secondary hydroxyl group in the intermediate with the acid anhydride (a 3). When the acid anhydride (a 3) contains the acid dianhydride (a 3-2) and the acid monoanhydride (a 3-1), a part of the secondary hydroxyl groups in the intermediate is reacted with the acid dianhydride (a 3-2), and the other part of the secondary hydroxyl groups in the intermediate is reacted with the acid monoanhydride (a 3-1). Thus, the carboxyl group-containing resin (A1) can be synthesized. At this time, the carboxyl group-containing resin (A1) has a bisphenol fluorene skeleton (S1), a structure (S4), and a structure (S5).

The carboxyl group-containing resin (A1) may further have a structure (S6) represented by the following formula (6). Structure (S6) is produced by reacting only one of the two anhydride groups in the acid dianhydride (a 3-2) with the secondary hydroxyl group in the intermediate. In formula (6), A is a carboxylic acid residue and D is an acid dianhydride residue. The a comprises a carboxylic acid residue comprising an unsaturated group.

When a part of the epoxy groups in the epoxy compound (A1) remain unreacted during the synthesis of the intermediate, the carboxyl group-containing resin (A1) may have a structure (S2) represented by formula (2), that is, epoxy groups. In addition, when a part of the structure (S3) in the intermediate is left unreacted, the carboxyl group-containing resin (A1) may have the structure (S3).

When the acid anhydride (a 3) contains the acid dianhydride (a 3-2), the number of the structures (S2) and the structures (S6) in the carboxyl group-containing resin (A1) can be reduced or the structures (S2) and the structures (S6) can be substantially removed from the carboxyl group-containing resin (A1) by optimizing the reaction conditions at the time of synthesis of the carboxyl group-containing resin (A1).

As described above, the carboxyl group-containing resin (A1) has a bisphenol fluorene skeleton (S1), and the acid anhydride (a 3) may have a structure (S4) when it contains an acid monoanhydride (a 3-1), and may have a structure (S5) when it contains an acid dianhydride (a 3-2). When the acid anhydride (a 3) contains the acid monoanhydride (a 3-1), the carboxyl group-containing resin (A1) may have at least one of the structures (S2) and (S3). When the acid anhydride (a 3) contains the acid dianhydride (a 3-2), the carboxyl group-containing resin (A1) may have at least one of the structures (S2) and (S6). When the acid anhydride (a 3) contains the acid monoanhydride (a 3-1) and the acid dianhydride (a 3-2), the carboxyl group-containing resin (A1) may have at least one of the structures (S2), (S3) and (S6).

In the case where the epoxy compound (A1) itself has a secondary hydroxyl group, that is, in the case where n=1 or more in the formula (7) described below, for example, the carboxyl group-containing resin (A1) may have a structure in which the secondary hydroxyl group in the epoxy compound (A1) reacts with the acid anhydride (a 3).

The structure of the carboxyl group-containing resin (A1) is reasonably estimated based on the technical common knowledge, and the structure of the carboxyl group-containing resin (A1) cannot be determined by analysis in practice. The reason for this is as follows. When the epoxy compound (A1) itself has a secondary hydroxyl group (for example, when n in the formula (7) is 1 or more), the structure of the carboxyl group-containing resin (A1) greatly varies depending on the number of secondary hydroxyl groups in the epoxy compound (A1). In addition, when the intermediate is reacted with the acid dianhydride (a 3-2), as described above, there may be a case where two secondary hydroxyl groups present in one molecule of the intermediate are crosslinked with the acid dianhydride (a 3-2) and a case where two secondary hydroxyl groups respectively present in two molecules of the intermediate are crosslinked with the acid dianhydride (a 3-2). Therefore, the carboxyl group-containing resin (A1) finally obtained contains a plurality of molecules having different structures from each other, and the structure cannot be determined even if the carboxyl group-containing resin (A1) is analyzed.

The carboxyl group-containing resin (A1) has an ethylenically unsaturated group derived from the unsaturated group-containing carboxylic acid (a 2-1) and is therefore photoreactive. Therefore, the carboxyl group-containing resin (A1) can impart photosensitivity (specifically, ultraviolet curability) to the photosensitive adhesive composition. Further, since the carboxyl group-containing resin (A1) has a carboxyl group derived from the acid anhydride (a 3), developability due to an alkaline aqueous solution containing at least one of an alkali metal salt and an alkali metal hydroxide can be imparted to the photosensitive adhesive composition. In addition, when the acid anhydride (a 3) contains the acid dianhydride (a 3-2), the molecular weight of the carboxyl group-containing resin (A1) depends on the amount of crosslinking by the acid dianhydride (a 3-2). Thus, a carboxyl group-containing resin (A1) having an appropriately adjusted acid value and molecular weight can be obtained. When the acid anhydride (a 3) contains the acid dianhydride (a 3-2) and the acid monoanhydride (a 3-1), the carboxyl group-containing resin (A1) having a desired molecular weight and acid value can be easily obtained by controlling the amounts of the acid dianhydride (a 3-2) and the acid monoanhydride (a 3-1) and the amount of the acid monoanhydride (a 3-1) relative to the acid dianhydride (a 3-2).

The weight average molecular weight of the carboxyl group-containing resin (A1) is preferably 700 to 10000. If the weight average molecular weight is 700 or more, the tackiness of the film formed from the photosensitive adhesive composition is further suppressed, and the insulation reliability and plating resistance of the cured product are further improved. In addition, if the weight average molecular weight is 10000 or less, the developability of the photosensitive adhesive composition due to the alkaline aqueous solution is remarkably improved. The weight average molecular weight is more preferably 900 to 8000, particularly preferably 1000 to 5000.

The solid content acid value of the carboxyl group-containing resin (A1) is preferably 60mgKOH/g to 140mgKOH/g. In this case, the developability of the photosensitive adhesive composition is remarkably improved. The acid value of the solid component is more preferably 80 to 135mgKOH/g, still more preferably 90 to 130mgKOH/g.

The polydispersity of the carboxyl group-containing resin (A1) is preferably 1.0 to 4.8. In this case, the cured product formed from the photosensitive adhesive composition can be provided with excellent developability while ensuring good insulation reliability and plating resistance (for example, whitening resistance in electroless nickel/gold treatment). The polydispersity of the carboxyl group-containing resin (A1) is more preferably 1.1 to 4.0, and still more preferably 1.2 to 2.8. The polydispersity is a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the carboxyl group-containing resin (A1).

The weight average molecular weight (Mw) of the carboxyl group-containing resin (A1) was calculated from the molecular weight measurement result obtained by gel permeation chromatography. The molecular weight measurement in gel permeation chromatography can be performed under the following conditions, for example.

GPC apparatus: SHODEX SYSTEM 11, manufactured by SHODEX SYSTEM Co., ltd

Column: the 4 SHODEX KF-800P, KF-005, KF-003 and KF-001 are connected in series

Mobile phase: THF (tetrahydrofuran)

Flow rate: 1 ml/min

Column temperature: 45 DEG C

A detector: RI (RI)

Conversion: and (3) polystyrene.

The reaction conditions of the carboxyl group-containing resin (A1) in the synthesis of the carboxyl group-containing resin (A1) will be described in detail.

The epoxy compound (a 1) has a structure (S7) represented by the following formula (7), for example. N in the formula (7) is, for example, a number of 0 to 20. In order to properly set the molecular weight of the carboxyl group-containing resin (A1), the average value of n is particularly preferably 0 to 1. If the average value of n is in the range of 0 to 1, particularly when the acid anhydride (a 3) contains the acid dianhydride (a 3-2), excessive increase in molecular weight due to addition of the acid dianhydride (a 3-2) is easily suppressed.

The carboxylic acid (a 2) contains a carboxylic acid (a 2-1) containing an unsaturated group. The carboxylic acid (a 2) may contain only the unsaturated group-containing carboxylic acid (a 2-1). Alternatively, the carboxylic acid (a 2) may contain a carboxylic acid (a 2-1) containing an unsaturated group and a carboxylic acid other than the carboxylic acid (a 2-1) containing an unsaturated group.

The unsaturated group-containing carboxylic acid (a 2-1) may contain, for example, a compound having only 1 ethylenically unsaturated group in one molecule. More specifically, the unsaturated group-containing carboxylic acid (a 2-1) may contain, for example, at least one compound selected from the group consisting of acrylic acid, methacrylic acid, ω -carboxy-polycaprolactone (n≡2) monoacrylate, crotonic acid, cinnamic acid, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl phthalic acid, 2-acryloyloxypropyl phthalic acid, 2-methacryloyloxypropyl phthalic 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 hexahydrophthalic acid. Preferably, the unsaturated group-containing carboxylic acid (a 2-1) contains acrylic acid.

The carboxylic acid (a 2) may comprise a polybasic acid (a 2-2). The polybasic acid (a 2-2) is an acid in which 2 or more hydrogen atoms in 1 molecule can be replaced with metal atoms. The polybasic acid (a 2-2) preferably has 2 or more carboxyl groups. At this time, the epoxy compound (a 1) reacts with both the unsaturated group-containing carboxylic acid (a 2-1) and the polybasic acid (a 2-2). The increase in molecular weight can be obtained by crosslinking the epoxy groups present in 2 molecules of the epoxy compound (a 1) with the polybasic acid (a 2-1). This can further control the tackiness of the film formed from the photosensitive adhesive composition, and can further improve the insulation reliability and plating resistance of the cured product.

The polybasic acid (a 2-2) preferably contains a dicarboxylic acid. The polybasic acid (a 2-2) may contain, for example, one or more compounds selected from the group consisting of 4-cyclohexene-1, 2-dicarboxylic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, and terephthalic acid. Preferably, the polyacid (a 2-2) contains 4-cyclohexene-1, 2-dicarboxylic acid.

When the epoxy compound (a 1) is reacted with the carboxylic acid (a 2), an appropriate method can be employed. For example, the carboxylic acid (a 2) is added to the solvent solution of the epoxy compound (a 1), and if necessary, the thermal polymerization inhibitor and the catalyst are further added and stirred and mixed, thereby obtaining a reactive solution. The reaction of the reactive solution is carried out by a conventional method at a temperature of preferably 60℃to 150℃and particularly preferably 80℃to 120℃to thereby obtain an intermediate. The solvent in this case may contain at least one component selected from ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, and dialkyl glycol ethers. The thermal polymerization inhibitor may contain, for example, at least one of hydroquinone and hydroquinone monomethyl ether. The catalyst may contain at least one component selected from tertiary amines such as benzyl dimethylamine and triethylamine, quaternary ammonium salts such as trimethyl benzyl ammonium chloride and methyl triethyl ammonium chloride, triphenylphosphine and triphenylantimony.

The catalyst particularly preferably contains triphenylphosphine. That is, the epoxy compound (a 1) is preferably reacted with the carboxylic acid (a 2) in the presence of triphenylphosphine. In this case, the ring-opening addition reaction of the epoxy group in the epoxy compound (a 1) and the carboxylic acid (a 2) can be promoted, and a reaction rate (conversion rate) of 95% or more, 97% or more, or almost 100% can be achieved. Therefore, the intermediate having the structure (S3) can be obtained in high yield. In addition, the occurrence of ion migration in the layer containing the cured product of the photosensitive adhesive composition can be suppressed, and the insulation reliability of the layer can be further improved.

The amount of carboxylic acid (a 2) is preferably 0.5 to 1.2 moles based on 1 mole of epoxy group of the epoxy compound (a 1) when the epoxy compound (a 1) is reacted with the carboxylic acid (a 2). In this case, a photosensitive adhesive composition having excellent photosensitivity and stability can be obtained. From the same viewpoint, the amount of the unsaturated group-containing carboxylic acid (a 2-1) is preferably 0.5 to 1.2 mol, more preferably 0.8 to 1.2 mol, relative to 1 mol of the epoxy group of the epoxy compound (a 1). Or, when the carboxylic acid (a 2) contains a carboxylic acid other than the unsaturated group-containing carboxylic acid (a 2-1), the amount of the unsaturated group-containing carboxylic acid (a 2-1) may be 0.5 to 0.95 mol based on 1 mol of the epoxy group of the epoxy compound (a 1). When the carboxylic acid (a 2) contains the polybasic acid (a 2-2), the amount of the polybasic acid (a 2-2) is preferably 0.025 mol to 0.25 mol based on 1 mol of the epoxy group of the epoxy compound (a 1). In this case, a photosensitive adhesive composition having excellent photosensitivity and stability can be obtained.

The intermediate thus obtained has a hydroxyl group formed by the reaction of the epoxy group of the epoxy compound (a 1) and the carboxyl group of the carboxylic acid (a 2).

The acid monoanhydride (s 3-1) is a compound having one acid anhydride group. The acid monoanhydride (a 3-1) may contain an anhydride of a dicarboxylic acid. The acid monoanhydride (a 3-1) may contain, for example, at least one compound selected from the group consisting of phthalic anhydride, 1,2,3, 6-tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, methylsuccinic anhydride, maleic anhydride, citraconic anhydride, glutaric anhydride, cyclohexane-1, 2, 4-tricarboxylic acid-1, 2-anhydride, and itaconic anhydride. It is particularly preferred that the acid monoanhydride (a 3-1) contains 1,2,3, 6-tetrahydrophthalic anhydride. That is, the acid anhydride (a 3) preferably contains 1,2,3, 6-tetrahydrophthalic anhydride. That is, it is preferable that the carboxyl group-containing resin (A1) has the structure (S4) and that B in the formula (4) contains 1,2,3, 6-tetrahydrophthalic anhydride residues. In this case, the film formed from the photosensitive adhesive composition can be further suppressed in tackiness while ensuring good developability of the photosensitive adhesive composition, and the insulation reliability and plating resistance of the cured product can be further improved. The amount of 1,2,3, 6-tetrahydrophthalic anhydride relative to the whole acid monoanhydride (a 3-1) is preferably 20 to 100 mol%, more preferably 40 to 100 mol%, but is not limited to these ranges.

The acid dianhydride (a 3-2) is a compound having two acid anhydride groups. The acid dianhydride (a 3-2) may contain an anhydride of a tetracarboxylic acid. The acid dianhydride (a 3-2) may contain, for example, a compound selected from the group consisting of 1,2,4, 5-benzene tetracarboxylic acid dianhydride, benzophenone tetracarboxylic acid dianhydride, methylcyclohexene tetracarboxylic acid dianhydride, naphthalene-1, 4,5, 8-tetracarboxylic acid dianhydride, ethylene tetracarboxylic acid dianhydride, 9' -bis (3, 4-dicarboxyphenyl) fluorene dianhydride, glycerol bis (dehydrated trimellitate) monoacetate, ethylene glycol bis (dehydrated trimellitate), 3', at least one compound selected from 4,4' -diphenyl sulfone tetracarboxylic dianhydride, 1, 3a,4,5,9 b-hexahydro-5 (tetrahydro-2, 5-dioxo-3-furyl) naphtho [ 1,2-c ] furan-1, 3-dione, 1,2,3, 4-butane tetracarboxylic dianhydride and 3,3', 4' -biphenyl tetracarboxylic dianhydride. It is particularly preferred that the acid dianhydride (a 3-2) contains 3,3', 4' -biphenyl tetracarboxylic dianhydride. That is, it is preferable that D in the formulas (5) and (6) contains 3,3', 4' -biphenyltetracarboxylic dianhydride residues. In this case, the film formed from the photosensitive adhesive composition can be further suppressed in tackiness while ensuring good developability of the photosensitive adhesive composition, and the insulation reliability and plating resistance of the cured product can be further improved. The amount of 3,3', 4' -biphenyltetracarboxylic dianhydride relative to the entire acid dianhydride (a 3-2) is preferably 20 to 100% by mole, more preferably 40 to 100% by mole, but is not limited to these ranges.

When reacting the intermediate with the acid anhydride (a 3), an appropriate method can be employed. For example, the acid anhydride (a 3) is added to the solvent solution of the intermediate, and the thermal polymerization inhibitor and the catalyst are further added as needed, followed by stirring and mixing, thereby obtaining a reactive solution. The carboxyl group-containing resin (A1) can be obtained by reacting the reactive solution at a temperature of preferably 60℃to 150℃and particularly preferably 80℃to 120℃by a conventional method. As the solvent, the catalyst and the polymerization inhibitor, suitable ones may be used, or the solvent, the catalyst and the polymerization inhibitor used in the synthesis of the intermediate may be directly used.

The catalyst particularly preferably contains triphenylphosphine. That is, the intermediate is preferably reacted with the acid anhydride (a 3) in the presence of triphenylphosphine. In this case, the reaction between the secondary hydroxyl group in the intermediate and the acid anhydride (a 3) can be promoted, and a reaction rate (conversion rate) of 90% or more, 95% or more, 97% or more, or almost 100% can be achieved. Therefore, the carboxyl group-containing resin (A1) having at least one of the structures (S4) and (S5) can be obtained in high yield. In addition, the occurrence of ion migration in the layer containing the cured product of the photosensitive adhesive composition can be suppressed, and the insulation reliability of the layer can be further improved.

When the acid anhydride (a 3) contains the acid dianhydride (a 3-2) and the acid monoanhydride (a 3-1), the amount of the acid dianhydride (a 3-2) is preferably 0.05 to 0.24 mole based on 1 mole of the epoxy group of the epoxy compound (a 1). The amount of the acid monoanhydride (a 3-1) is preferably 0.3 to 0.7 mole based on 1 mole of the epoxy group of the epoxy compound (a 1). In this case, the carboxyl group-containing resin (A1) having an appropriately adjusted acid value and molecular weight can be easily obtained.

It is also preferable to carry out the reaction of the intermediate with the acid anhydride (a 3) under bubbling of air. In this case, the development property of the photosensitive adhesive composition due to the alkaline aqueous solution is remarkably improved by suppressing an excessive increase in the molecular weight of the carboxyl group-containing resin (A1) to be produced.

The carboxyl group-containing resin (a) may contain only the carboxyl group-containing resin (A1) or only the carboxyl group-containing resin other than the carboxyl group-containing resin (A1), or may contain the carboxyl group-containing resin (A1) and the carboxyl group-containing resin other than the carboxyl group-containing resin (A1). The carboxyl group-containing resins other than the carboxyl group-containing resin (A1) include carboxyl group-containing resins having no bisphenol fluorene skeleton (hereinafter, also referred to as carboxyl group-containing resins (A2)).

The carboxyl group-containing resin (A2) may contain, for example, a compound having a carboxyl group and not having photopolymerization (hereinafter referred to as a (A2-1) component). The (A2-1) component 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 may contain a compound such as acrylic acid, methacrylic acid, and ω -carboxyl-polycaprolactone (n.apprxeq.2) monoacrylate. The ethylenically unsaturated compound having a carboxyl group may contain a reactant with a dibasic acid anhydride such as pentaerythritol triacrylate or pentaerythritol trimethacrylate. The ethylenically unsaturated monomer may further contain an ethylenically unsaturated compound having no carboxyl group such as 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl phthalate, and linear or branched aliphatic or alicyclic (meth) acrylate in which an unsaturated bond may be locally present 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 component (A2-2)). The carboxyl group-containing resin (A2) may contain only the component (A2-2). The component (A2-2) contains a resin (referred to as a first resin (x)) which is a reactant of an intermediate compound (x 1) having two or more epoxy groups in one molecule and an ethylenically unsaturated compound (x 2) with at least one compound (x 3) selected from polycarboxylic acids and anhydrides thereof. The first resin (x) is obtained, for example, by reacting an epoxy group in the epoxy compound (x 1) with a carboxyl group in the ethylenically unsaturated compound (x 2) to obtain an intermediate, and adding the compound (x 3) to the intermediate. The epoxy compound (x 1) may contain an appropriate epoxy compound such as a cresol novolac type epoxy compound, a phenol novolac type epoxy compound, or a biphenyl novolac type epoxy compound. It is particularly preferable that the epoxy compound (x 1) contains at least 1 compound selected from the group consisting of biphenyl novolak type epoxy compounds and cresol novolak type epoxy compounds. The epoxy compound (x 1) may contain only a biphenyl novolak type epoxy compound or only a cresol novolak type epoxy compound. The epoxy compound (x 1) may contain a polymer of an ethylenically unsaturated compound (z). The ethylenically unsaturated compound (z) contains, for example, a compound (z 1) having an epoxy group such as glycidyl (meth) acrylate or a compound (z 2) having no epoxy group such as 2- (meth) acryloyloxyethyl phthalate. The ethylenically unsaturated compound (x 2) preferably contains at least one of acrylic acid and methacrylic acid. The compound (x 3) contains, for example, one or more compounds selected from the group consisting of polycarboxylic acids such as phthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, and anhydrides of these polycarboxylic acids. It is particularly preferred that compound (x 3) contains at least 1 polycarboxylic acid selected from phthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid.

The (A2-2) component may contain a resin (referred to as a second resin (y)) which is a reactant 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 ethylenically unsaturated monomer may further contain an ethylenically unsaturated compound having no carboxyl group. The second resin (y) is obtained by reacting a part of carboxyl groups in the polymer with an ethylenically unsaturated compound having an epoxy group. 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, acrylic acid, methacrylic acid, ω -carboxyl-polycaprolactone (n.apprxeq.2) monoacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, and the like. The ethylenically unsaturated compound having no carboxyl group contains, for example, 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl phthalate, linear or branched aliphatic or alicyclic (wherein the ring may have an unsaturated bond locally) or the like. 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 both the carboxyl group-containing resin (A1) and the carboxyl group-containing resin (A2). The carboxyl group-containing resin (a) preferably contains 30 mass% or more of the carboxyl group-containing resin (A1), more preferably 50 mass% or more, still more preferably 60 mass% or more, still more preferably 100 mass% or more. In this case, the heat resistance and insulation reliability of the cured product of the photosensitive adhesive composition can be remarkably improved. In addition, the tackiness of the film formed of the photosensitive adhesive composition can be sufficiently reduced. Further, the developability of the photosensitive adhesive composition due to the alkaline aqueous solution can be ensured. Therefore, the photosensitive adhesive composition can be suitably used for forming an insulating layer.

The photopolymerization initiator (B) is a component capable of improving photosensitivity of the photosensitive adhesive composition. The photopolymerization initiator (B) preferably contains, for example, an acylphosphine oxide-based photopolymerization initiator (B1). In this case, when the photosensitive adhesive composition is exposed to light such as ultraviolet rays, high photosensitivity can be imparted to the photosensitive adhesive composition. In addition, the occurrence of ion migration in the layer containing the cured product of the photosensitive adhesive composition can be suppressed, and the insulation reliability of the layer can be further improved. In addition, the acylphosphine oxide-based photopolymerization initiator (B1) is less likely to inhibit electrical insulation of the cured product. Therefore, even when the photosensitive adhesive composition is cured by exposure to light, a cured product excellent in electrical insulation can be obtained, and this cured product is suitable as, for example, an interlayer insulating layer.

The acylphosphine oxide-based photopolymerization initiator (B1) may contain at least one component selected from the group consisting of a monoacylphosphine oxide-based photopolymerization initiator such as 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4, 6-trimethylbenzoyl-ethyl-phenyl-phosphinate, and a bis (2, 6-dichlorobenzoyl) phenylphosphine oxide, bis (2, 6-dichlorobenzoyl) -2, 5-dimethylphenylphosphine oxide, bis (2, 6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis (2, 6-dichlorobenzoyl) -1-naphtylphosphine oxide, bis (2, 6-dimethoxybenzoyl) phenylphosphine oxide, bis (2, 6-dimethoxybenzoyl) -2, 4-trimethylpentylphosphine oxide, bis (2, 6-dimethoxybenzoyl) -2, 5-dimethylphenylphosphine oxide, bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide, and bis (2, 5, 6-trimethylbenzoyl) -2, 4-trimethylpentylphosphine oxide. It is particularly preferable that the acylphosphine oxide-based photopolymerization initiator (B1) contains 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide, and it is also preferable that the acylphosphine oxide-based photopolymerization initiator (B1) contains only 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide.

The photopolymerization initiator (B) preferably contains a hydroxyketone photopolymerization initiator (B2) in addition to the acylphosphine oxide photopolymerization initiator (B1). That is, the photosensitive adhesive composition preferably contains a hydroxyketone photopolymerization initiator (B2). In this case, compared with the case where the hydroxy ketone photopolymerization initiator (B2) is not contained, higher photosensitivity can be imparted to the photosensitive adhesive composition. Thus, when a coating film formed from the photosensitive adhesive composition is cured by irradiation with light such as ultraviolet light, the coating film can be sufficiently cured from the surface to the deep portion. Examples of the hydroxyketone photopolymerization initiator (B2) include 1-hydroxy-cyclohexyl-phenyl-ketone, phenylglyoxylic acid methyl ester, 1- [4- (2-hydroxyethoxy) -phenyl ] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl ] phenyl } -2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-phenyl-propan-1-one.

The mass ratio of the acylphosphine oxide-based photopolymerization initiator (B1) to the hydroxyketone-based photopolymerization initiator (B2) is preferably 1:0.01 to 1: 10. In this case, the curability in the vicinity of the surface of the coating film formed from the photosensitive adhesive composition and the curability in the deep portion can be improved in a balanced manner.

The photopolymerization initiator (B) preferably also contains a photopolymerization initiator (B3) having a benzophenone skeleton. That is, the photosensitive adhesive composition preferably contains the acylphosphine oxide-based photopolymerization initiator (B1) and the photopolymerization initiator (B3) having a benzophenone skeleton, or contains the acylphosphine oxide-based photopolymerization initiator (B1), the hydroxyketone-based photopolymerization initiator (B2) and the photopolymerization initiator (B3) having a benzophenone skeleton. In this case, when the coating film formed of the photosensitive adhesive composition is developed after being partially exposed, curing of the unexposed portion can be suppressed, and therefore, the resolution becomes particularly high. Therefore, a cured product of the photosensitive adhesive composition having a very fine pattern can be formed. In particular, when an interlayer insulating layer of a multilayer printed wiring board is formed from a photosensitive adhesive composition and a small-diameter hole for a through hole is formed in the interlayer insulating layer by photolithography (see fig. 3), the small-diameter hole can be precisely and easily formed. Examples of the photopolymerization initiator (B3) having a benzophenone skeleton include bis (diethylamino) benzophenone.

The amount of the photopolymerization initiator (B3) having a benzophenone skeleton relative to the acylphosphine oxide-based photopolymerization initiator (B1) is preferably 0.5 to 20 mass%. If the amount of the photopolymerization initiator (B3) having a benzophenone skeleton relative to the acylphosphine oxide-based photopolymerization initiator (B1) is 0.5 mass% or more, the resolution becomes particularly high. If the amount of the photopolymerization initiator (B3) having a benzophenone skeleton relative to the acylphosphine oxide-based photopolymerization initiator (B1) is 20 mass% or less, the photopolymerization initiator (B3) having a benzophenone skeleton is less likely to inhibit electrical insulation of a cured product of the photosensitive adhesive composition. From the same viewpoint, the amount of bis (diethylamino) benzophenone relative to the acylphosphine oxide-based photopolymerization initiator (B1) is preferably 0.5 to 20 mass%.

The photosensitive adhesive composition may further contain a photopolymerization accelerator, a sensitizer, and the like as appropriate. For example, the photosensitive adhesive composition may contain oxime esters selected from 1, 2-octanedione-1- [4- (phenylthio) -2- (O-benzoyl oxime) ], ethanone-1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -1- (O-acetyl oxime), and the like; benzoin and alkyl ethers thereof; acetophenones such as acetophenone and benzil dimethyl ketal; anthraquinones such as 2-methylanthraquinone; thioxanthones such as 2, 4-dimethylthioxanthone, 2, 4-diethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, and 2, 4-diisopropylthioxanthone; benzophenone such as benzophenone and 4-benzoyl-4' -methyl diphenyl sulfide; xanthones such as 2, 4-diisopropylxanthone; alpha-hydroxyketones such as 2-hydroxy-2-methyl-1-phenyl-propan-1-one; at least one component selected from nitrogen atom-containing compounds such as 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholino-1-propanone. The photosensitive adhesive composition may contain a photopolymerization initiator (B), a photopolymerization accelerator and a sensitizer, which are suitable for tertiary amine systems such as ethyl p-dimethylbenzoate, isoamyl p-dimethylaminobenzoate and 2-dimethylaminoethyl benzoate. The photosensitive adhesive composition may contain at least one of a photopolymerization initiator for visible light exposure and a photopolymerization initiator for near infrared light exposure, as required. The photosensitive adhesive composition may contain a photopolymerization initiator (B), a coumarin derivative such as 7-diethylamino-4-methylcoumarin as a sensitizer for a laser exposure method, a carbocyanine dye, a xanthene dye, or the like.

The photopolymerizable compound (C) can impart photocurability to the photosensitive adhesive composition. The photopolymerizable compound (C) preferably contains at least one selected from the group consisting of photopolymerizable monomers and photopolymerizable prepolymers. The photopolymerizable monomer may contain, for example, a monofunctional (meth) acrylate selected from 2-hydroxyethyl (meth) acrylate and the like; and at least one compound of polyfunctional (meth) acrylates such as diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epsilon-caprolactone-modified pentaerythritol hexa acrylate, and tricyclodecane dimethanol di (meth) acrylate.

Particularly, the photopolymerizable compound (C) contains a trifunctional compound, i.e., a compound having three unsaturated bonds in one molecule. In this case, the resolution of the film formed of the photosensitive adhesive composition is improved when the film is exposed and developed, and the developability of the photosensitive adhesive composition due to the alkaline aqueous solution is also improved. The trifunctional compound may contain, for example, at least one compound selected from the group consisting of trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate, and epsilon-caprolactone-modified tris (2-acryloyloxyethyl) isocyanurate, and ethoxylated glycerol tri (meth) acrylate.

The photopolymerizable compound (C) preferably also contains a phosphorus-containing compound (phosphorus-containing unsaturated compound). In this case, the flame retardancy of the cured product of the photosensitive adhesive composition is improved. The phosphorus-containing unsaturated compound may contain at least one compound selected from the group consisting of 2-methacryloyloxyethyl acid phosphate (specifically, product numbers LIGHT ESTER P-1M and LIGHT ESTER P-2M manufactured by Kagaku chemical Co., ltd.), 2-acryloyloxyethyl acid phosphate (specifically, product number LIGHT ACRYLATE P-1A manufactured by Kagaku chemical Co., ltd.), diphenyl-2-methacryloyloxyethyl phosphate (specifically, product number MR-260 manufactured by Daiki Kagaku Kogyo Co., ltd.), and HFA series (specifically, product numbers HFA-3003 and HFA-6127) which are addition reactants of dipentaerythritol hexaacrylate and HCA (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), and caprolactone-modified dipentaerythritol hexaacrylate and HCA (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide).

The photopolymerizable prepolymer may contain, for example, at least one compound selected from prepolymers obtained by polymerizing a monomer having an ethylenically unsaturated bond and then adding an ethylenically unsaturated group, and oligo (meth) acrylate prepolymers. The oligo (meth) acrylate prepolymer may contain, for example, at least one member selected from the group consisting of epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) acrylate, alkyd (meth) acrylate, silicone (meth) acrylate and spiro resin (meth) acrylate.

The photosensitive adhesive composition preferably contains an organic filler (D). If the photosensitive adhesive composition contains the organic filler (D), the effect of improving the bonding strength when the first and second members 1 and 2 are bonded by bonding the first and second adhesive layers 11 and 12 formed of the photosensitive adhesive composition to each other on the first and second members 1 and 2 is remarkable. The organic filler (D) has high compatibility with the photosensitive adhesive composition, and can impart more strong thixotropic properties to the photosensitive adhesive composition. Therefore, the moldability in forming the adhesive layer from the photosensitive adhesive composition can be improved.

The organic filler (D) preferably has at least one functional group selected from the group consisting of a carboxyl group, an epoxy group and an amino group. In this case, the bonding strength when bonding the first member 1 and the second member 2 by bonding the first adhesive layer 11 and the second adhesive layer 12 formed of the photosensitive adhesive composition to each other on the first member 1 and the second member 2 can be remarkably improved.

In particular, when the photosensitive adhesive composition contains an organic filler having a carboxyl group (hereinafter also referred to as an organic filler (D1)), the developability of the photosensitive adhesive composition can be improved. In addition, the photosensitive adhesive composition can reduce the unevenness of the cured product layer caused by the fluidity of the photosensitive adhesive composition by containing the organic filler (D1). This makes it easy to make the thickness of the cured product layer uniform. In this case, the photosensitive adhesive composition may not contain a rheology control agent. The carboxyl group of the organic filler (D1) may be formed as a side chain of a product thereof by polymerizing or crosslinking a carboxylic acid monomer such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, or the like, for example. The carboxylic acid monomer has a carboxyl group and a polymerizable unsaturated double bond. The organic filler (D1) improves the thixotropic properties of the photosensitive adhesive composition, and thus improves the stability (particularly, storage stability) of the photosensitive adhesive composition. Further, since the organic filler (D1) has a carboxyl group, it is possible to improve the developability of the cured product containing the photosensitive adhesive composition, and to improve the compatibility of the crystalline epoxy resin (E1) described later, thereby preventing crystallization in the photosensitive adhesive composition. For the carboxyl group content of the organic filler (D1), the acid value of the organic filler (D1) is preferably 1mgKOH/g to 60mgKOH/g in terms of acid value measured by acid-base titration. If the acid value is less than 1mgKOH/g, the stability of the photosensitive adhesive composition and the developability of the cured product may be lowered. If the acid value is more than 60mgKOH/g, the moisture resistance reliability of the cured product may be lowered. The acid value of the organic filler (D1) is more preferably 3mgKOH/g to 40mgKOH/g.

When the organic filler (D) has an amino group, the organic filler (D) contains, for example, melamine. When the organic filler (D) having an amino group contains melamine, the content of melamine is preferably 0.1 to 6 mass% based on 100 parts by mass of the carboxyl group-containing resin (a).

The organic filler (D) also preferably has hydroxyl groups. In this case, the bonding strength can be further improved when the first adhesive layer 11 and the second adhesive layer 12 formed of the photosensitive adhesive composition are bonded to each other to bond the first member 1 and the second member 2.

The average primary particle diameter of the organic filler (D) is preferably 1 μm or less. By setting the average primary particle diameter of the organic filler (D) to 1 μm or less, the thixotropic property of the photosensitive adhesive composition can be efficiently improved. Therefore, the stability of the photosensitive adhesive composition is further improved. Further, by setting the average primary particle diameter of the organic filler (D) to 1 μm or less, the organic filler can be uniformly dispersed, and the first adhesive layer 11 and the second adhesive layer 12 can be adhered to each other, so that the bonding strength when the first member 1 and the second member 2 are bonded to each other can be improved. The lower limit of the average primary particle diameter of the organic filler (D) is not particularly limited, and is preferably 0.001 μm or more, for example. The average primary particle diameter of the organic filler (D) was measured as D50 by a laser diffraction type particle size distribution measuring apparatus. The average primary particle diameter of the organic filler (D) is more preferably 0.4 μm or less, and still more preferably 0.1 μm or less. In this case, the roughness of the roughened surface formed on the cured product can be made particularly fine. In addition, scattering at the time of exposure can be suppressed in the photosensitive adhesive composition, whereby the resolution of the photosensitive adhesive composition can be further improved.

The organic filler (D) is preferably dispersed in the photosensitive adhesive composition at a maximum particle diameter of less than 1.0. Mu.m, more preferably at a maximum particle diameter of less than 0.5. Mu.m. The maximum particle diameter is measured by, for example, a laser diffraction type particle size distribution measuring apparatus. Or the maximum particle diameter is measured by observing the cured product with a Transmission Electron Microscope (TEM). The organic filler (D) may be aggregated in the photosensitive adhesive composition (for example, secondary particles may be formed), and in this case, the maximum particle diameter means the size of the aggregated particles. If the maximum particle diameter of the organic filler (D) in a dispersed state is in the above range, the roughness of the roughened surface formed on the cured product can be made finer. In addition, scattering at the time of exposure can be suppressed in the photosensitive adhesive composition, whereby the resolution of the photosensitive adhesive composition can be further improved. In addition, the stability of the photosensitive adhesive composition can be improved. The average primary particle diameter of the organic filler (D) is 0.1 μm or less, and the organic filler (D) is particularly preferably dispersed in a particle diameter of 0.5 μm or less. When aggregation of particles occurs, the maximum particle diameter is generally larger than the average primary particle diameter.

The organic filler (D) preferably contains a rubber component. The rubber component can impart flexibility to the cured product of the photosensitive adhesive composition. The rubber component may be composed of a resin. The rubber component preferably contains at least 1 polymer selected from the group consisting of 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 adhesive composition. In this case, a more moderate rough surface can be provided on the surface of the cured product layer. The rubber component contains a crosslinked structure formed when the monomers constituting the above 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 3 components, methyl methacrylate, butadiene, and styrene, and is classified as butadiene rubber. SBR is generally a copolymer of styrene and butadiene, and is classified as styrene rubber. Specific examples of the organic filler (D) include product number XER-91-MEK manufactured by JSR corporation, product number XER-32-MEK manufactured by JSR corporation, and product number XSK-500 manufactured by JSR corporation. Among these organic fillers (D), XER-91-MEK is a crosslinked rubber (NBR) having carboxyl groups and an average primary particle diameter of 0.07. Mu.m, and is provided in the form of a dispersion of methyl ethyl ketone in which the content of the crosslinked rubber is 15% by weight, and the acid value thereof is 10.0mgKOH/g. XER-32-MEK is a dispersion in which a polymer (linear particles) of a carboxyl group-modified hydrogenated nitrile rubber is dispersed in methyl ethyl ketone so that the content of the polymer relative to the total amount of the dispersion is 17% by weight. XSK-500 is a crosslinked rubber (SBR) having carboxyl groups and hydroxyl groups and having an average primary particle diameter of 0.07. Mu.m, and is provided as a dispersion of methyl ethyl ketone in which the content of the crosslinked rubber is 15% by weight. In this way, the organic filler (D) can be blended in the photosensitive adhesive composition in the form of a dispersion. That is, the rubber component may be blended in the photosensitive adhesive composition in the form of a dispersion. Further, specific examples of the organic filler (D) include, in addition to the above, the product number XER-92 manufactured by JSR corporation.

The organic filler (D) may contain a particle component other than the rubber component. At this time, the organic filler (D) may contain, for example, at least 1 particle component selected from the group consisting of acrylic resin fine particles having carboxyl groups and cellulose fine particles having carboxyl groups. The acrylic resin fine particles having a carboxyl group may contain at least 1 particle component selected from the group consisting of non-crosslinked styrene acrylic resin fine particles and crosslinked styrene acrylic resin fine particles. Specific examples of the non-crosslinked styrene/acrylic resin fine particles include product No. FS-201 (average primary particle diameter 0.5 μm) manufactured by LTD. Co. Nipponpaint Industrial Coatings. Specific examples of the crosslinked styrene-acrylic resin fine particles include product No. MG-351 (average primary particle diameter 1.0 μm) and product No. BGK-001 (average primary particle diameter 1.0 μm) manufactured by LTD. Co.No. Nipponpaint Industrial Coatings. The organic filler (D) may contain a particle component other than the particle component selected from the rubber component, the acrylic resin fine particles, and the cellulose fine particles. In this case, the organic filler (D) may contain a particle component having a carboxyl group. That is, the particle component having a carboxyl group may be different from the particle component selected from the group consisting of a rubber component, acrylic fine particles and cellulose fine particles.

When the photosensitive adhesive composition contains the organic filler (D), the organic filler (D) may scatter light in the photosensitive adhesive composition upon exposure. In this case, the photosensitive adhesive composition preferably contains the aforementioned acylphosphine oxide-based photopolymerization initiator (B1) and hydroxyketone-based photopolymerization initiator (B2). Thus, even when the photosensitive adhesive composition is exposed to light and cured, good developability can be obtained. The mass ratio of the acylphosphine oxide-based photopolymerization initiator (B1) to the hydroxyketone-based photopolymerization initiator (B2) is particularly preferably 1:0.01 to 1: 1. From the same viewpoint, the photosensitive adhesive composition preferably contains a photopolymerization initiator (B3) having a benzophenone skeleton, and in this case, the amount of the photopolymerization initiator (B3) having a benzophenone skeleton is particularly preferably 1 to 18% by mass relative to the acylphosphine oxide-based photopolymerization initiator (B1). From the same viewpoint, the amount of bis (diethylamino) benzophenone is particularly preferably 1 to 18% by mass relative to the acylphosphine oxide photopolymerization initiator (B1).

The photosensitive adhesive composition preferably further contains an epoxy compound (E). In this case, the bonding strength can be further improved when the first adhesive layer 11 and the second adhesive layer 12 formed of the photosensitive adhesive composition are bonded to each other to bond the first member 1 and the second member 2 to each other. Further, the insulation properties of the multilayer substrate 10 formed by joining the first member 1 and the second member 2 can be improved.

The epoxy compound (E) can impart thermosetting properties to the photosensitive adhesive composition. The epoxy compound (E) preferably contains a crystalline epoxy resin (E1). In this case, the developability of the layer formed by the photosensitive adhesive composition can be improved. In this case, if the photosensitive adhesive composition further contains the organic filler (D1), the carboxyl group in the organic filler (D1) can improve the compatibility of the crystalline epoxy resin (E1). This prevents the crystalline epoxy resin (E1) in the photosensitive adhesive composition from being recrystallized. The epoxy compound (E) may further contain an amorphous epoxy resin (E2). 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 (E1) preferably contains one or more components selected from 1,3, 5-tris (2, 3-epoxypropyl) -1,3, 5-triazine-2, 4,6 (1 h,3h,5 h) -trione, hydroquinone-type crystalline epoxy resin (specific example, trade name YDC-1312 manufactured by mitsubishi chemical corporation), biphenyl-type crystalline epoxy resin (specific example, trade name YX-4000 manufactured by mitsubishi chemical corporation), diphenyl ether-type crystalline epoxy resin (specific example, NIPPON STEEL Chemical & Material co., ltd. Product No. YSLV-80 DE), bisphenol-type crystalline epoxy resin (specific example, trade name YSLV-80XY manufactured by new japanese chemical corporation), tetraphenol-ethane-type crystalline epoxy resin (specific example, product No. GTR-1800 manufactured by japan chemical corporation), bisphenol fluorene-type crystalline epoxy resin (specific example, epoxy resin having structure (S7)).

The crystalline epoxy resin (E1) preferably has 2 epoxy groups in 1 molecule. In this case, cracking of the cured product can be made less likely during repeated temperature changes.

The crystalline epoxy resin (E1) preferably has an epoxy equivalent of 150g/eq to 300 g/eq. The epoxy equivalent is the gram weight of the crystalline epoxy resin (E1) containing 1 gram equivalent of epoxy groups. The crystalline epoxy resin (E1) has a melting point. The crystalline epoxy resin (E1) has a melting point of, for example, 70℃to 180 ℃.

The epoxy compound (E) preferably contains a crystalline epoxy resin (E1-1) having a melting point of 110℃or lower. In this case, the developability of the photosensitive adhesive composition due to the alkaline aqueous solution is remarkably improved. In this case, the resolution (opening) of the adhesive layer formed of the photosensitive adhesive composition can be improved. The crystalline epoxy resin (E1-1) having a melting point of 110 ℃ or lower may contain at least one component selected from, for example, a biphenyl type epoxy resin (specifically, product number YX-4000 manufactured by Mitsubishi chemical corporation), a biphenyl ether type epoxy resin (specifically, product number YSLV-80DE manufactured by Nippon iron and gold chemical corporation), a bisphenol type epoxy resin (specifically, product number YSLV-80XY manufactured by Nippon iron and gold chemical corporation), and a bisphenol fluorene type crystalline epoxy resin (specifically, an epoxy resin having the structure (S7)).

The amorphous epoxy resin (E2) preferably contains, for example, a phenol novolac type epoxy resin (specifically, product number EPICLON-775 manufactured by DIC Co., ltd.), a cresol novolac type epoxy resin (specifically, product number EPICLON-695 manufactured by DIC Co., ltd.), a bisphenol A novolac type epoxy resin (specifically, product number EPICLON-865 manufactured by DIC Co., ltd.), a bisphenol A type epoxy resin (specifically, product number jER1001 manufactured by Mitsubishi chemical Co., ltd.), a bisphenol F type epoxy resin (specifically, product number jER4004P manufactured by Mitsubishi chemical Co., ltd.), a bisphenol S type epoxy resin (specifically, product number EPICLON EXA-1514 manufactured by DIC Co., ltd.), bisphenol AD type epoxy resin, biphenyl novolak type epoxy resin (product number NC-3000 manufactured by Japanese chemical Co., ltd.), hydrogenated bisphenol A type epoxy resin (product number ST-4000D manufactured by Nippon Kagaku Co., ltd.), naphthalene type epoxy resin (product number EPICLON HP-4032 manufactured by DIC Co., ltd.), EPICLON HP-4700, EPICLON HP-4770 manufactured by DIC Co., ltd.), tert-butyl catechol type epoxy resin (product number EPICLON HP-820 manufactured by DIC Co., ltd.), dicyclopentadiene type epoxy resin (product number EPICLON HP-7200 manufactured by DIC Co., ltd.), adamantane type epoxy resin (product number EPICLON HP-7200 manufactured by DIC Co., ltd.), ADAMANTATEX-E-201, product number of Mitsubishi chemical corporation), special difunctional epoxy resins (as specific examples, product numbers YL7175-500 and YL7175-1000, product number of Mitsubishi chemical corporation; EPICLON TSR-960, EPICLON TER-601, EPICLON TSR-250-80BX, EPICLON 1650-75MPX, EPICLON EXA-4850, EPICLON EXA-4816, EPICLON EXA-4812 and EPICLON EXA-9726 manufactured by DIC Co., ltd; at least one component selected from YSLV-120TE, a rubber-like core-shell polymer modified bisphenol A type epoxy resin (product No. MX-156, zhong Hua, zhong Hua) and a rubber-like core-shell polymer modified bisphenol F type epoxy resin (product No. MX-136, zhong Hua, kane Ace MX-130).

When the photosensitive adhesive composition contains the epoxy compound (E), it is preferable that the photosensitive adhesive composition contains both the crystalline epoxy resin (E1) and the amorphous epoxy resin (E2). In this case, the bonding strength of the adhesive layers made of the photosensitive adhesive composition can be further improved when the adhesive layers are bonded to each other, and the resolution (opening property) of the adhesive layers can be further improved.

The epoxy compound (E) may contain a phosphorus-containing epoxy resin. In this case, the flame retardancy of the cured product of the photosensitive adhesive composition is improved. The phosphorus-containing epoxy resin may be contained in the crystalline epoxy resin (E1) or in the amorphous epoxy resin (E2). Examples of the phosphorus-containing epoxy resin include phosphoric acid-modified bisphenol F-type epoxy resin (specifically, EPICLON EXA-9726 and EPICLON EXA-9710, manufactured by DIC Co., ltd.), and EPOTOHOTO FX-305, manufactured by Nippon Kagaku Co., ltd.).

The amounts of the components in the photosensitive adhesive composition are appropriately adjusted so that the photosensitive adhesive composition has photocurability and can be developed with an alkaline solution.

The amount of the carboxyl group-containing resin (A) is preferably from 5 to 85% by mass, more preferably from 10 to 75% by mass, still more preferably from 20 to 50% by mass, based on the solid content of the photosensitive adhesive composition. Further, the amount of the carboxyl group-containing resin (A1) is preferably from 5 to 85% by mass, more preferably from 10 to 75% by mass, still more preferably from 20 to 50% by mass, based on the solid content of the photosensitive adhesive composition. The amount of the photopolymerization initiator (B) relative to the carboxyl group-containing resin (a) is preferably 0.1 to 30 mass%, and more preferably 1 to 25 mass%.

The amount of the photopolymerizable compound (C) relative to the carboxyl group-containing resin (a) is preferably in the range of 1 to 50% by mass, more preferably in the range of 10 to 45% by mass, still more preferably in the range of 21 to 40% by mass.

When the photosensitive adhesive composition contains the organic filler (D), the content of the organic filler (D) relative to the carboxyl group-containing resin (a) is preferably 0.1 to 60 mass%. The content of the organic filler (D) relative to the carboxyl group-containing resin (a) is more preferably 0.5 to 30% by mass, still more preferably 1 to 17% by mass, and particularly preferably 3 to 15% by mass.

When the organic filler (D) contains a rubber component, the content of the rubber component relative to the carboxyl group-containing resin (a) is preferably 1 to 60% by mass, more preferably 2 to 20% by mass, and still more preferably 3 to 17% by mass.

When the photosensitive adhesive composition contains the epoxy compound (E), the total of the equivalents of the epoxy groups contained in the epoxy compound (E) is preferably 0.7 to 2.5, more preferably 0.7 to 2.3, and even more preferably 0.7 to 2.0, relative to 1 equivalent of the carboxyl groups contained in the carboxyl group-containing resin (a), with respect to the amount of the epoxy compound (E). The total of the equivalents of the epoxy groups contained in the crystalline epoxy resin (E1) is preferably 0.1 to 2.0, more preferably 0.2 to 1.9, and even more preferably 0.3 to 1.5 relative to 1 equivalent of the carboxyl groups contained in the carboxyl group-containing resin (a). Or the total of the equivalents of the epoxy groups contained in the crystalline epoxy resin (E1) may be 0.7 to 2.5 relative to 1 equivalent of the carboxyl groups contained in the carboxyl group-containing resin (A).

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

The photosensitive adhesive composition may contain a blocked isocyanate selected from toluene diisocyanate, morpholine diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate blocked with caprolactam, oxime, malonate or the like; butyl urea resin; various thermosetting resins other than the above; ultraviolet curable epoxy (meth) acrylate; resins obtained by adding (meth) acrylic acid to epoxy resins such as bisphenol a type, phenol novolac type, cresol novolac type, alicyclic type and the like; and at least one resin selected from the group consisting of diallyl phthalate resin, phenoxy resin, urethane resin, and a polymer compound such as a fluororesin.

The photosensitive adhesive composition may contain a curing agent for curing the epoxy compound (E). The curing agent may contain, for example, imidazole derivatives selected from imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole and the like; amine compounds such as dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzylamine, and 4-methyl-N, N-dimethylbenzylamine; hydrazine compounds such as adipoyl hydrazine and sebacoyl hydrazine; phosphorus compounds such as triphenylphosphine; an acid anhydride; a phenol; a mercaptan; lewis acid amine complexes; and At least one component of the salt. Examples of commercial products of these components include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ and 2P4MHZ (both trade names of imidazole-based compounds) manufactured by Sikukuku Kagaku Kogyo Co., ltd., U-CAT3503N, UCAT3502T (both trade names of blocked isocyanate compounds of dimethylamine) manufactured by San-Apro Co., ltd., DBU, DBN, U-CATSA102 and U-CAT5002 (both of bicyclic amidine compounds and salts thereof).

The photosensitive adhesive composition may further contain an inorganic filler. Examples of the inorganic filler include silica filler, barium sulfate, carbon nanotube, talc, bentonite, aluminum hydroxide, magnesium hydroxide and titanium oxide. For example, when the photosensitive adhesive composition contains a white material such as titanium oxide or zinc oxide, the photosensitive adhesive composition and its cured product can be made white.

The photosensitive adhesive composition may contain an adhesion imparting agent. If the photosensitive adhesive composition contains an adhesion-imparting agent, the adhesion of the layer in contact with the photosensitive adhesive composition can be improved. Examples of the adhesion imparting agent include guanamine derivatives such as acetoguanamine (2, 4-diamino-6-methyl-1, 3, 5-triazine) and benzoguanamine (2, 4-diamino-6-phenyl-1, 3, 5-triazine), and s-triazine derivatives such as 2, 4-diamino-6-methacryloyloxyethyl-s-triazine, 2-vinyl-4, 6-diamino-s-triazine-isocyanuric acid adduct and 2, 4-diamino-6-methacryloyloxyethyl-s-triazine-isocyanuric acid adduct.

The photosensitive adhesive composition may contain a rheology control agent. The tackiness of the photosensitive adhesive composition is easily optimized by the rheology control agent. Examples of the rheology control agent include urea-modified medium-polarity polyamides (BYK-430, BYK-431, product numbers BYK-405, product numbers BYK-411, BYK-420, product numbers BYK-40, product numbers BYK-415, product numbers BYK-425, product numbers BYK-428, product numbers, and product numbers), polyurethane (BYK-Chemie Japan, product numbers BYK-428, product numbers, castor oil wax, polyethylene wax, polyamide wax, bentonite, kaolin, clay, and clay.

The photosensitive adhesive composition may contain a curing accelerator; a colorant; copolymers of silicones, acrylates, and the like; a leveling agent; a thixotropic agent; polymerization inhibitor; antihalation agents; a flame retardant; a defoaming agent; an antioxidant; a surfactant; a pigment; and at least one component of a polymeric dispersant.

In the preparation of the photosensitive adhesive composition of the present embodiment, for example, the raw materials of the photosensitive adhesive composition are mixed and kneaded by an appropriate kneading method such as a three-roll mill, a ball mill, or a sand mill, for example, to prepare the photosensitive adhesive composition. The photosensitive adhesive composition can be prepared by first kneading the raw materials including liquid components, low-viscosity components, and the like, and then adding the liquid components, low-viscosity components, and the like to the obtained mixture to prepare a mixture. When the photosensitive adhesive composition contains a solvent, a part or all of the solvent in the raw materials is mixed first and then mixed with the remaining raw materials. When the photosensitive adhesive composition contains the organic filler (D), a dispersion of the organic filler (D) is used, and the photosensitive adhesive composition can be prepared by mixing the above-described raw material components other than the organic filler (D) in the dispersion.

In view of storage stability and the like, the first agent can be prepared by mixing a part of the components of the photosensitive adhesive composition, and the second agent can be prepared by mixing the remaining part of the components. That is, the photosensitive adhesive composition may include a first agent and a second agent. In this case, for example, the first agent can be prepared by mixing and dispersing the photopolymerizable compound (C), a part of the solvent, and the thermosetting component in advance in the components of the photosensitive adhesive composition, and the second agent can be prepared by mixing and dispersing the remaining part of the components of the photosensitive adhesive composition. In this case, the first agent and the second agent may be mixed in a desired amount to prepare a mixed solution, and the first adhesive layer 11 and the second adhesive layer 12 may be prepared from the mixed solution.

The photosensitive adhesive composition preferably has a property that a film having a thickness of 25 μm produced from the photosensitive adhesive composition can be developed with an aqueous sodium carbonate solution. In this case, the first adhesive layer 11 and the second adhesive layer 12 can be made sufficiently thick from the photosensitive adhesive composition by photolithography. Of course, the first adhesive layer 11 and the second adhesive layer 12 thinner than 25 μm in thickness may be produced from the photosensitive adhesive composition.

Whether or not a film having a thickness of 25 μm can be developed with an aqueous sodium carbonate solution can be confirmed by the following method. By applying a coating to a suitable substrateThe photosensitive adhesive composition was applied thereon to form a wet coating film, and the wet coating film was heated at 80℃for 40 minutes, thereby forming a film having a thickness of 25. Mu.m. In a state in which a negative mask having an ultraviolet-transmitting exposure portion and an ultraviolet-blocking non-exposure portion was directly brought into contact with the film, the film was exposed to a light of 500mJ/cm ² The film is exposed to ultraviolet rays under the condition of (2). After exposure, 1% Na was sprayed on the film at 30℃for 90 seconds under a spray pressure of 0.2MPa ₂ CO ₃ After the aqueous solution, pure water was sprayed at a spray pressure of 0.2MPa for 90 seconds. When the film was observed after the treatment, and as a result, the portion of the film corresponding to the non-exposed portion was removed and no residue was observed, it was judged that the film having a thickness of 25 μm could be developed with an aqueous sodium carbonate solution. It should be noted that, in the case of a film having another thickness (for example, 30 μm), it is also possible to confirm whether or not development can be performed with an aqueous sodium carbonate solution.

A method of joining the first member 1 and the second member 2 using the photosensitive adhesive composition according to the present embodiment and a method of manufacturing the multilayer substrate 10 will be described with reference to fig. 2A to 2E.

As described above, the photosensitive adhesive composition is used for producing the first adhesive layer 11 and the second adhesive layer 12 when the first member 1 and the second member 2 are bonded via the first adhesive layer 11 and the second adhesive layer 12 by bonding the first adhesive layer 11 and the second adhesive layer 12, which are respectively overlapped on the first member 1 and the second member 2. Therefore, the photosensitive adhesive composition can be used to produce the multilayer substrate 10 from the first member 1 and the second member 2.

The method of forming the first adhesive layer 11 and the second adhesive layer 12 on the first member 1 and the second member 2, respectively, may employ an appropriate method, specifically, for example, as described below.

First, the first member 1 and the second member 2 are prepared (see fig. 2A). The first member 1 and the second member 2 are not particularly limited as long as they are members formed of an appropriate material. The first part 1 and the second part 2 may be formed of the same material. More specifically, examples of the first member 1 and the second member 2 include a polyethylene terephthalate (PET) film, glass, polycarbonate, cyclic olefin polymer, liquid crystal polymer, glass epoxy resin substrate, metal-clad laminate, silicon wafer, and circuit board having conductor wiring such as a printed wiring board. As shown in fig. 1, the first member 1 and the second member 2 may be, for example, printed wiring boards each including an insulating layer 5, conductor wirings 3 and 3 provided on one surface of the insulating layer 5 and the other surface opposite to the insulating layer, and a through hole 40 for conducting between the conductor wirings 3 and 3.

Hereinafter, a first example of a process for manufacturing the multilayer substrate 10 when the first member 1 and the second member 2 are printed wiring boards including the conductor wiring 3 will be described in detail with reference to fig. 2A to 2E.

The photosensitive adhesive composition is applied to the first member 1, and the photosensitive adhesive composition is further heated to be dried or semi-cured as necessary, whereby the first adhesive layer 11 can be produced on the first member 1. The photosensitive adhesive composition is applied to the second member 2, and the photosensitive adhesive composition is further heated to be dried or semi-cured as necessary, whereby the second adhesive layer 12 can be formed on the second member 2 (see fig. 2B). As a method of applying the photosensitive adhesive composition, a suitable method may be employed, and examples thereof include dipping, spraying, spin coating, roll coating, curtain coating, screen printing, and the like. When the photosensitive adhesive composition is heated, for example, when the photosensitive adhesive composition contains a solvent, the photosensitive adhesive composition is heated at a temperature in the range of 60 to 120 ℃ in order to volatilize the solvent.

The first adhesive layer 11 and the second adhesive layer 12 may be made of dry films containing a dried or semi-cured photosensitive adhesive composition, respectively. In this case, for example, a photosensitive adhesive composition is first applied to a suitable support made of polyester or the like, and then heated, whereby a dry film which is a dried product or semi-cured product of the photosensitive adhesive composition is formed on the support. Thus, a laminate (dry film with support) comprising a dry film and a support for supporting the dry film was obtained. After the dry films in the laminate are overlapped on the first member 1, pressure is applied to the dry films and the first member 1, and then the support is peeled off from the dry films, whereby the dry films are transferred from the support to the first member 1. Thus, the first adhesive layer 11 made of a dry film is provided on the first member 1. In the same way, a second adhesive layer 12 made of a dry film is provided on the second component 2.

The first adhesive layer 11 and the second adhesive layer 12 may be cured by exposure to light, respectively. The photosensitive adhesive composition has photosensitivity, and thus can be cured by exposure to light. For example, the first adhesive layer 11 and the second adhesive layer 12 may be irradiated with light such as ultraviolet rays to expose the entire surfaces thereof. The light source for exposure is selected from, for example, a chemical lamp, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, LED, YAG, g rays (436 nm), h rays (405 nm), i rays (365 nm), and a combination of two or more of g rays, h rays, and i rays. The light source is not limited to these, and may be a light source capable of irradiating light capable of curing the photosensitive adhesive composition. When the first adhesive layer 11 and the second adhesive layer 12 are produced by the dry film method described above, the dry film in the laminate is superimposed on the first member 1 and the second member 2, and then the support is peeled off from the dry film by exposing the dry film to light such as ultraviolet rays through the support without peeling off the support.

The thickness of each of the first adhesive layer 11 and the second adhesive layer 12 is not particularly limited, and may be, for example, 1 μm to 100 μm.

Next, the first adhesive layer 11 and the second adhesive layer 12 are overlapped (see fig. 2C). Thus, a laminate in which the first member 1, the first adhesive layer 11, the second adhesive layer 12, and the second member 2 were laminated in this order was obtained. The laminate is hot-pressed using a vacuum lamination apparatus (vacuum laminator) or the like (see fig. 2D). Thereby, the first adhesive layer 11 is adhered to the second adhesive layer 12, and the first member 1 and the second member 2 are bonded via the first adhesive layer 11 and the second adhesive layer 12. Thus, a multilayer substrate 10 is obtained (see fig. 2E). The conditions of the hot pressing may be appropriately adjusted so as to bond the first adhesive layer 11 and the second adhesive layer 12, for example, the pressing pressure is 0.01MPa to 30MPa, the heating temperature is 50 ℃ to 300 ℃, and the hot pressing time is 1 second to 60 minutes. In the present embodiment, it is also preferable that the laminate is heated after hot pressing as described above, thereby obtaining the multilayer substrate 10. Thus, the multilayer substrate 10 having more excellent bonding strength between the first member 1 and the second member 2 is obtained. The heating conditions may be appropriately set, and the heating temperature is preferably, for example, 50 to 300℃and the heating time is preferably, for example, 5 to 300 minutes. The heating temperature is more preferably 80 to 280 ℃, still more preferably 100 to 250 ℃, particularly preferably 130 to 200 ℃. The heating time is more preferably 10 minutes to 250 minutes, still more preferably 20 minutes to 200 minutes, and particularly preferably 30 minutes to 180 minutes. When the photosensitive adhesive composition contains a crystalline epoxy resin, it is more preferable to heat the composition at a temperature equal to or higher than the melting point of the crystalline epoxy resin. At this time, the bonding strength is further improved.

As described above, according to the present embodiment, the first adhesive layer 11 on the first member 1 and the second adhesive layer 12 on the second member 2 are overlapped and bonded, so that the first member 1 and the second member 2 are bonded via the first adhesive layer 11 and the second adhesive layer 12, thereby manufacturing the multilayer substrate 10.

In the above description, the method of manufacturing the multilayer substrate 10 in which 2 members (the first member 1 and the second member 2) are joined together, such as the multilayer substrate 10 in which the first member 1 and the second member 2 are joined together via the first adhesive layer 11 and the second adhesive layer 12, is described with reference to fig. 2A to 2E. The multilayer substrate 10 may be produced by joining 3 or more members, as long as the members are joined by bonding the adhesive layers formed of the photosensitive adhesive composition described above.

When the first member 1 and the second member 2 are each a printed wiring board, the printed wiring board may have only one insulating layer or may be a multilayer printed wiring board having a plurality of insulating layers as described above. That is, each of the first member 1 and the second member 2 may be a printed wiring board or the like in which several tens of layers, for example, 10 or more layers each, are laminated.

The electrically insulating layer such as the solder resist layer and the interlayer insulating layer may be formed from a coating film or a dry film of the photosensitive adhesive composition according to the present embodiment.

A second example of the method of manufacturing the multilayer substrate 10 will be described with reference to fig. 3A to 3F. In the second example, the photosensitive adhesive composition according to the present embodiment is used to form the first adhesive layer 11 and the second adhesive layer 12 having appropriate patterns by photolithography or the like, and then the first member 1 and the second member 2 are bonded. Note that, the duplicate description of the method described in the first example is appropriately omitted. In the case where the first adhesive layer 11 and the second adhesive layer 12 have appropriate patterns, a high bonding strength between the first member 1 and the second member 2 can be achieved by bonding the first adhesive layer 11 and the second adhesive layer 12 to each other.

First, the first member 1 and the second member 2 are prepared. The first member 1 and the second member 2 each include an insulating layer 5 and a conductor wiring 3 (see fig. 3A) overlapped with the insulating layer 5. The first member 1 and the second member 2 are each, for example, a printed wiring board. The thickness of the first member 1 and the second member 2 is not particularly limited, and is, for example, 1 μm to 10mm.

The photosensitive adhesive composition is applied to the first member 1 so as to cover the conductor wiring 3, thereby forming a film. The film may be dried by heating the film.

A dry film made of the photosensitive adhesive composition may be superimposed on the first member 1 so as to cover the conductor wiring 3, thereby forming a film made of the dry film. At this time, as in the case of the first example described above, for example, after the dry film in the laminate including the dry film and the support is superimposed on the first member 1, pressure is applied to the dry film and the first member 1, and then the support is peeled off from the dry film, whereby the dry film is transferred from the support to the first member 1. Thereby, a film made of a dry film is provided on the first member 1. A film made of a dry film was formed on the second member 2 by the same method.

The first adhesive layer 11 is formed of a film by photolithography (see fig. 3B). Specifically, the film is irradiated with ultraviolet rays in a state where the negative mask is in contact with the film, whereby the film portion is exposed, and the exposed portion is cured.

The negative mask includes, for example, an exposure portion that transmits ultraviolet light and a non-exposure portion that blocks ultraviolet light. The non-exposure portion is provided at a position corresponding to the position of an opening 4 described later, for example. The negative mask is an optical device such as a mask film or a dry plate. The light source of the ultraviolet rays may be the same as the light source described above. The exposure method may be a method other than a method using a negative mask. For example, the adhesive layer may be exposed by a direct drawing method in which only a portion of the adhesive layer to be exposed is irradiated with ultraviolet light emitted from a light source.

The second adhesive layer 12 is formed on the first member 2 by the same method as in the case of the first adhesive layer 11 (see fig. 3B).

When the first adhesive layer 11 is formed from a dry film, the dry film in the laminate is superimposed on the first member 1, and then the film formed from the dry film is exposed to light such as ultraviolet rays through the support without peeling the support, and then the support is peeled from the film.

Next, the film is developed using a developer such as an alkaline solution, whereby unexposed portions of the film are removed. Thereby, the first adhesive layer 11 having a pattern can be manufactured. In the example shown in fig. 3C, the first adhesive layer 11 has an opening 4, and a part of the conductor wiring 3 is exposed at the bottom of the opening 4.

In the development treatment, an appropriate developer may be used depending on the composition of the photosensitive adhesive composition. The developer is, for example, an alkaline aqueous solution or an organic amine containing at least one of an alkali metal salt and an alkali metal hydroxide. The alkaline aqueous solution more specifically contains at least one component selected from, for example, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium hydroxide, potassium hydroxide, ammonium hydroxide, tetramethylammonium hydroxide, and lithium hydroxide. The solvent in the alkaline aqueous solution may be water alone or a mixture of water and a hydrophilic organic solvent such as a lower alcohol. The organic amine contains, for example, at least one component selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine and triisopropanolamine.

The developer is preferably an alkaline aqueous solution containing at least one of an alkali metal salt and an alkali metal hydroxide, and particularly preferably an aqueous sodium carbonate solution. In this case, improvement of the working environment and reduction of the burden of waste disposal can be achieved.

In addition, the second adhesive layer 12 having a pattern is formed on the second member 2 by the same method as in the case of forming the first adhesive layer 11 (see fig. 3C).

Next, as in the case described above with reference to fig. 2C to D, the first adhesive layer 11 and the second adhesive layer 12 are overlapped. Thus, a laminate in which the first member 1, the first adhesive layer 11, the second adhesive layer 12, and the second member 2 were laminated in this order was obtained. The laminate is hot-pressed using a vacuum lamination apparatus (vacuum laminator) or the like (see fig. 3D and 3E). Thereby, the first adhesive layer 11 is adhered to the second adhesive layer 12, and the first member 1 and the second member 2 are bonded via the first adhesive layer 11 and the second adhesive layer 12. Thus, the multilayer substrate 10 is obtained (see fig. 3F).

When the first adhesive layer 11 and the second adhesive layer 12 are overlapped, for example, as shown in fig. 3D, the opening 4 of the first adhesive layer 11 and the opening 4 of the second adhesive layer 12 are overlapped. Thus, a hole 41 penetrating the bonding layer 13 is formed in the bonding layer 13 (see fig. 3E, for example). By disposing the conductive material 30 in the hole 41, the conductor wiring 3 of the first member 1 and the conductor wiring 3 of the second member 2 can be electrically connected via the conductive material 30. Specifically, for example, the conductive material 30 is disposed on the conductor wiring 3 of the first member 1 at a portion exposed at the bottom of the opening 4. In this state, the first adhesive layer 11 and the second adhesive layer 12 are overlapped and bonded by hot pressing. At this time, the conductive material 30 is melted, for example, and electrically connected to the first member 1 and the second member 2, respectively. Thereby, the conductive material 30 electrically connects the conductor wirings 3 to each other. The conductive material 30 is not particularly limited as long as it is a material having conductivity, and examples of the conductive material 30 include solder balls, conductive pastes, and the like.

The conductive material 30 is placed on the conductor wiring 3 and the portions of the first adhesive layer 11 and the second adhesive layer 12 removed by exposure (for example, the openings 4 shown in fig. 3C). At this time, the conductor wirings 3 in the first member 1 and the second member 2 may be electrically connected to each other via the conductive material 30.

In the opening 4 or the hole 41, electronic components such as a semiconductor chip, a register, and an inductor may be disposed. At this time, the multilayer substrate 10 with the electronic component built therein can be obtained.

In the present embodiment, it is also preferable that the laminate is heated after hot pressing as described above to obtain the multilayer substrate 10. Thus, the multilayer substrate 10 having more excellent bonding strength between the first member 1 and the second member 2 can be obtained.

As described above, in the present embodiment, even if the first adhesive layer 11 and the second adhesive layer 12 having patterns are formed from the photosensitive adhesive composition by photolithography, the first member 1 and the second member 2 can be bonded by the first adhesive layer 11 and the second adhesive layer 12. That is, the photosensitive adhesive composition of the present embodiment can provide the first adhesive layer 11 and the second adhesive layer 12 with a high-definition pattern, and can achieve high bonding strength between the first member 1 and the second member 2.

Examples

Hereinafter, specific embodiments of the present invention are shown. However, the present invention is not limited to the examples.

(1) Synthesis of carboxyl group-containing resin

(1-1) Synthesis example 1 (carboxyl group-containing resin A)

A bisphenol fluorene type epoxy compound (represented by formula (7), R in formula (7)) was charged into a four-necked flask equipped with a reflux condenser, thermometer, air blowing tube and stirrer ₁ ～R ₈ Epoxy compounds having an epoxy equivalent of 250g/eq for all hydrogen), 250 parts by mass, 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 part by mass of methylhydroquinone, 60 parts by mass of propylene glycol monoethyl ether acetate, and 140 parts by mass of diethylene glycol monoethyl ether acetate. They were stirred under air bubbling to prepare a mixture. The mixture was heated in a flask under stirring at a heating temperature of 115℃for a heating time of 12 hours while bubbling air. Thus, a solution of the intermediate was prepared.

Subsequently, 60.8 parts by mass of 1,2,3, 6-tetrahydrophthalic anhydride, 58.8 parts by mass of 3,3', 4' -biphenyltetracarboxylic dianhydride, and 38.7 parts by mass of propylene glycol monomethyl ether acetate were charged into the solution of the intermediate in the flask. They were heated under stirring with air bubbling and heating at a heating temperature of 115℃for a heating time of 6 hours. Then, the mixture was heated under stirring with air bubbling at a heating temperature of 80℃for a heating time of 1 hour. Thus, a 65 mass% solution of the carboxyl group-containing resin A was obtained. The carboxyl group-containing resin A had a polydispersity of 2.15, a weight average molecular weight of 3096, and an acid value of 105mgKOH.

(1-2) Synthesis example 2 (carboxyl group-containing resin B)

Into a four-necked flask equipped with a reflux condenser, a thermometer, an air blowing tube and a stirrer, 203 parts by mass of cresol novolak type epoxy resin (NIPPON STEEL Chemical & Material Co., manufactured by Ltd., product No. YDCN-700-5, epoxy equivalent 203), 106 parts by mass of diethylene glycol monoethyl ether acetate, 0.2 part by mass of methyl hydroquinone, 72 parts by mass of acrylic acid, and 1.5 parts by mass of triphenylphosphine were charged to prepare a mixture. The mixture was heated at a heating temperature of 100℃for 4 hours.

Then, 68 parts by mass of tetrahydrophthalic acid, 0.3 part by mass of methylhydroquinone, 0.5 part by mass of triphenylphosphine, and 29 parts by mass of diethylene glycol monoethyl ether acetate were added to the mixture, and the mixture was heated at a heating temperature of 90℃for 18 hours. Then, 34 parts by mass of naphtha (Swasol 1500) was further added thereto, and the mixture was heated at a heating temperature of 90℃for 5 hours. Thus, a 65 mass% solution of the carboxyl group-containing resin B was obtained. The epoxy equivalent of the carboxyl group-containing resin B was 9871g/eq.

(2) Preparation of photosensitive adhesive composition

Examples 1 to 18 and comparative examples 1 to 3

The powdery components among the components shown in tables 1 and 2 described below were dispersed in the carboxyl group-containing resin solution prepared in the above (1) by a three-roll mill, and then all the components shown in tables 1 and 2 described below were added to a flask as a diluent and mixed with stirring at a temperature of 35 ℃ as necessary, to prepare a photosensitive adhesive composition. The details of the components shown in tables 1 and 2 are as follows. The values of the amounts of the components shown in tables 1 and 2 are solid component amounts, and the values shown in brackets are solid component amounts for the organic fillers a to C, F.

Photopolymerization initiator a:2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide (product number Irgacure TPO, manufactured by BASF corporation).

Photopolymerization initiator B: 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF corporation, product number Irgacure 184).

Photopolymerization initiator C:4,4' -bis (diethylamino) benzophenone.

Photopolymerizable compound a: trimethylolpropane triacrylate.

Photopolymerizable compound B: a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (product number KAYARAD DPHA, manufactured by japan chemical Co., ltd.).

Dispersion of organic filler a: a dispersion (product No. XER-91-MEK, manufactured by JSR Co., ltd., acid value: 10.0 mgKOH/g) was obtained by dispersing crosslinked rubber (NBR) having an average primary particle diameter of 0.07 μm in methyl ethyl ketone so that the content thereof was 15% by weight based on the total amount of the dispersion.

Dispersion of organic filler B: a dispersion (product No. XSK-500, manufactured by JSR Co., ltd.) was obtained by dispersing crosslinked rubber (SBR) having an average primary particle diameter of 0.07 μm in methyl ethyl ketone so that the content thereof was 15% by weight based on the total amount of the dispersion.

Dispersion of organic filler C: polymers of carboxy-modified hydrogenated nitrile rubbers. (Dispersion obtained by dispersing a rubber as linear particles in methyl ethyl ketone so that the content of the rubber relative to the total amount of the dispersion was 17% by weight (product number XER-32-MEK manufactured by JSR Co., ltd.)

Organic filler D: epoxy group-containing organic filler powder (glycidyl group-modified acrylonitrile butadiene rubber having an average primary particle diameter of 0.3 μm).

Organic filler E: micro powder melamine (manufactured by Nissan chemical Co., ltd.).

Organic filler F: zhong Hua Kane Ace MX-125, which is manufactured by Kabushiki Kaisha, contains 33 mass% of core-shell SBR particles in bisphenol A type epoxy resin. Epoxy equivalent 270 g/eq.).

Epoxy resin a: biphenyl type crystalline epoxy resin (trade name YX-4000, melting point 105 ℃ C., epoxy equivalent 187g/eq., manufactured by Mitsubishi chemical Co., ltd.).

Epoxy resin B: bisphenol type crystalline epoxy resin (NIPPON STEELChemical & Material Co., ltd., trade name YSLV-80XY, melting point 75-85 ℃ C., epoxy equivalent 192 g/eq.).

Solution of epoxy resin C: bisphenol A type epoxy resin (trade name: EPICLON EXA-4816, liquid resin; epoxy equivalent 410 g/eq) containing a long chain carbon chain was dissolved in diethylene glycol monoethyl ether acetate in a solid content of 90% (solid content of 90%) to give an epoxy equivalent of 455.56g/eq.

Epoxy resin D: bisphenol a type epoxy resin, NIPPON STEEL Chemical & Material co., ltd. Product number YD-128, epoxy equivalent 187g/eq.

Solvent: methyl ethyl ketone.

(3) Test piece production

Test pieces were prepared from the photosensitive adhesive compositions of examples and comparative examples as follows.

After the photosensitive adhesive composition was applied to a polyethylene terephthalate (PET) film by an applicator, the film was heated at 80 ℃ for 20 minutes, and then further heated to 110 ℃ for 5 minutes, and dried, thereby forming a dry film having a thickness of 20 μm on the film.

Next, the biaxially stretched polypropylene film was hot-pressed at a heating temperature of 70 ℃ on the dry film thus formed, and a cover film was formed on the dry film. The formed film was peeled off from the dry film, and then the dry film was laminated so as to cover the entire surface of a glass epoxy substrate (product number CS-3357, manufactured by Lichang industries Co., ltd.) having a thickness of 0.2mm, and heat lamination was performed by a vacuum laminator. The conditions for heat lamination were a pressure of 0.5MPa, a heating temperature of 70℃and a heating and pressurizing time of 45 seconds. Thus, a film having a thickness of 20 μm was formed on the glass epoxy substrate, and the film was used as a test piece.

(4) Evaluation test

The test pieces of examples 1 to 18 and comparative examples 1 to 3 produced in the above (3) were evaluated in accordance with the following procedure. The results are shown in tables 1 to 2 below.

(4-1) Low tackiness

In each of examples and comparative examples, when the cover film was peeled from the dry film, the low tackiness was evaluated according to the following evaluation criteria.

A: when the cover film is peeled off, the cover film can be peeled off smoothly without a large peeling sound.

B: when the cover film is peeled off, a peeling sound is generated.

C: when the cover film is peeled off, peeling noise is generated, and the photosensitive adhesive composition is transferred to the cover film.

(4-2) adhesiveness

In each of examples and comparative example 3, the film of the test piece was subjected to full-face exposure and cured, whereby 2 substrates having cured layers (adhesive layers) of the photosensitive adhesive composition on the members were prepared. The adhesive layers of the 2 substrates were bonded to each other, and heat laminated using a vacuum laminator. The conditions for heat lamination were a pressure of 0.5MPa, a heating temperature of 100℃and a heating time of 45 seconds. After the heat lamination, the 2 substrates were heated at a heating temperature of 180 ℃ for 120 minutes. After heating for 120 minutes, the adhesion strength of the copper foil of the copper-clad laminate was measured in accordance with the method of measuring JIS-C6481 in a multilayer substrate in which the adhesive layers of 2 members were bonded to each other, and the adhesion was evaluated according to the following criteria. In comparative example 3, a multilayer substrate was produced without reheating after heat lamination, and evaluation was performed.

In each of comparative examples 1 to 2, the film of the test piece was subjected to full-face exposure and cured, whereby 1 substrate having a cured product layer (adhesive layer) of the photosensitive adhesive composition and 1 substrate not having an adhesive layer on the member were prepared. A multilayer substrate was produced under the same conditions as described above by bonding an adhesive layer of a substrate having an adhesive layer on a member to a substrate having no adhesive layer, and evaluation was performed in the same manner as described above.

A: the adhesion strength was higher than 1.5 kN/m.

B: the adhesion strength is higher than 1.3kN/m and is less than 1.5 kN/m.

C: the adhesion strength is higher than 1.1kN/m and is less than 1.3 kN/m.

D: the adhesion strength is higher than 0.9kN/m and is less than 1.1 kN/m.

E: the adhesion strength is higher than 0.7kN/m and is less than 0.9 kN/m.

F: the adhesion strength is 0.7kN/m or less.

(4-3) openness

A negative mask having a non-exposure portion with a predetermined mask pattern (a negative mask having a non-exposure portion with a pattern having a circular shape with diameters of 80 μm, 60 μm, 40 μm and 20 μm) was directly contacted with the film of the test piece produced in (3), and in this state, the film was placed at 250mJ/cm via the negative mask ² The film was irradiated with light having wavelengths of 365nm and 405 nm. Thereby, a through hole is formed in the cured product of the coating film in the test piece. During the development treatment, 1% Na at 30℃was sprayed onto the film for 90 seconds at a spray pressure of 0.2MPa ₂ CO ₃ An aqueous solution. Then, pure water was sprayed on the film at a spray pressure of 0.2MPa for 90 seconds. Thereby, the unexposed portion of the coating film is removed. After exposure and before development, the polyethylene terephthalate film was peeled off from the dry film (film). The obtained exposed and developed test pieces were evaluated for the openness according to the following criteria.

A: circular pattern portions with a diameter of 20 μm are opened.

B: the circular pattern portion having a diameter of 40 μm was open, but the circular pattern portion having a diameter of 20 μm was not open.

C: the circular pattern portion having a diameter of 60 μm was open, but the circular pattern portion having a diameter of 40 μm was not open.

D: the circular pattern portion having a diameter of 80 μm was open, but the circular pattern portion having a diameter of 60 μm was not open.

E: the circular shape pattern portion having a diameter of 80 μm was free from openings.

(4-4) moisture resistance

In each of examples and comparative examples, a bonded sample (multilayer substrate) was prepared by the same method as the evaluation substrate of "(4-2) adhesiveness", and after being placed in a PCT tester at 121 ℃ and a humidity of 100% for 50 hours, the bonded state of 2 test pieces was observed, and the moisture resistance was evaluated according to the following criteria.

A: no peeling occurred.

B: peeling occurs.

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The same evaluation as described above was performed on samples prepared by changing the conditions for heat lamination or the heating conditions after heat lamination described in "(4-2) adhesiveness" of test pieces prepared with the same composition as in example 2, and the results (examples 19 to 23) are shown in table 3.

Example 19

The conditions for heat lamination were set to a pressure of 0.4MPa, a heating temperature of 100℃and a heating time of 45 seconds.

Example 20

The conditions for heat lamination were set to a pressure of 1.0MPa, a heating temperature of 70℃and a heating time of 45 seconds.

Example 21

The heating conditions after the heat lamination were set to a heating temperature of 150℃and a heating time of 30 minutes.

Example 22

The heating conditions after the heated lamination were set to a heating temperature of 95℃and a heating time of 60 minutes.

Example 23

The heating conditions after the heat lamination were set to 115℃for 60 minutes.

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Claims (5)

1. A method for manufacturing a multilayer substrate, wherein a first adhesive layer and a second adhesive layer are formed on a first member and a second member respectively from a photosensitive adhesive composition or a dry film containing a dried product of the photosensitive adhesive composition,

the first adhesive layer and the second adhesive layer are overlapped and bonded, so that the first member and the second member are bonded by hot pressing through the first adhesive layer and the second adhesive layer, and then further heated;

The photosensitive adhesive composition contains:

a carboxyl group-containing resin A,

a photopolymerization initiator B, wherein the composition of the composition,

photopolymerizable compound C, and

an epoxy compound E, which is a compound having a hydroxyl group,

the carboxyl group-containing resin A contains an ethylenically unsaturated group,

the epoxy compound E contains crystalline epoxy resin E1 and amorphous epoxy resin E2;

the heating temperature at the time of heating is a temperature equal to or higher than the melting point of the crystalline epoxy resin E1.

2. The method for producing a multilayer substrate according to claim 1, wherein the photosensitive resin composition further contains an organic filler D.

3. The method for producing a multilayer substrate according to claim 2, wherein the organic filler D has at least one functional group selected from a carboxyl group, an epoxy group, and an amino group.

4. The method for producing a multilayer substrate according to any one of claims 1 to 3, wherein the carboxyl group-containing resin a has a bisphenol fluorene skeleton.

5. The method for producing a multilayer substrate according to any one of claims 1 to 3, wherein the method comprises curing the first adhesive layer and the second adhesive layer by exposure to light and heating.