JP7679107B2 - Photosensitive composition, transparent cured film, laminate, and method for producing laminate - Google Patents

Description

The present invention relates to a photosensitive composition, a transparent cured film containing a cured product of this photosensitive composition, a laminate containing this transparent cured film, and a method for producing this laminate.

Patent Document 1 discloses a photosensitive resin composition that contains a binder polymer having a specific acid value, a photopolymerizable compound, and a photopolymerization initiator with a specific structure as a photosensitive resin composition that forms a protective film on a touch panel electrode. This photosensitive resin composition is capable of forming a resin cured film pattern with sufficient resolution even in a thin film, and further improves the resolution by using an ultraviolet absorber in combination.

International Publication No. 2013/084886

However, although the photosensitive resin composition of Patent Document 1 improves resolution by using an ultraviolet absorber in combination, there are concerns that the transparency and curability may decrease, and it is not easy to achieve high resolution while still providing satisfactory transparency and curability. In addition, there are concerns about precipitation of the ultraviolet absorber and bleeding out over long-term use.

The object of the present invention is to provide a photosensitive composition having high transparency and resolution, a transparent cured film containing a cured product of this photosensitive composition, a laminate containing this transparent cured film, and a method for producing the laminate.

A photosensitive composition according to one embodiment of the present invention contains a photosensitive resin (A) containing a resin having an ethylenically unsaturated group and a carboxyl group, a photopolymerization initiator (B), and a photopolymerizable compound (C). The photosensitive resin (A) contains a photosensitive resin (A1) produced by reacting an epoxy compound (a1) having at least two epoxy groups with a carboxylic acid (a2) having an ethylenically unsaturated group, and an acid anhydride (a3) containing an acid dianhydride (a4). The number average molecular weight Mn of the photosensitive resin (A1) is 500 or more and 2500 or less, the polydispersity Mw/Mn is 1.2 or more and 2.8 or less, and the acid value is 55 mgKOH/g or more and 130 mgKOH/g or less. When a dry film having a thickness of 10 μm is produced from the photosensitive composition, the light transmittance at wavelengths of 450 to 800 nm is 85% or more, the maximum absorbance of the dry film in the wavelength range of 250 to 800 nm is in the wavelength range of 300 to 330 nm, and the maximum absorbance is 1 or more.

The transparent cured film according to one embodiment of the present invention contains a cured product of the photosensitive composition.

The laminate according to one aspect of the present invention comprises a substrate and the transparent cured film overlying the substrate.

In one embodiment of the present invention, the method for producing a laminate involves applying the photosensitive composition onto a substrate to produce a dry film having a thickness dimension of 10 μm or less, partially exposing the dry film to light, and then developing the dry film with an alkaline developer to form a pattern, thereby producing a transparent cured film that overlaps the substrate.

The photosensitive composition, transparent cured film, and laminate of one embodiment of the present invention can achieve high resolution and excellent curability while maintaining high transparency.

The method for producing a laminate according to one aspect of the present invention produces a highly transparent laminate suitable for optical applications.

1A and 1B are cross-sectional views showing an outline of a laminate according to one embodiment of the present invention. 2A to 2E are schematic diagrams showing an example of a manufacturing process for the laminate of this embodiment.

The following describes the embodiments of the present invention. In the following description, "(meth)acrylic" means at least one of "acrylic" and "methacrylic". For example, (meth)acrylate means at least one of acrylate and methacrylate.

The photosensitive composition of this embodiment contains a photosensitive resin (A) containing a resin having an ethylenically unsaturated group and a carboxyl group, a photopolymerization initiator (B), and a photopolymerizable compound (C). The photosensitive resin (A) contains a photosensitive resin (A1) produced by reacting an epoxy compound (a1) having at least two epoxy groups with a carboxylic acid (a2) having an ethylenically unsaturated group, and an acid anhydride (a3) containing an acid dianhydride (a4). The number average molecular weight Mn of the photosensitive resin (A1) is 500 or more and 2500 or less, the polydispersity Mw/Mn is 1.2 or more and 2.8 or less, and the acid value is 55 mgKOH/g or more and 130 mgKOH/g or less. When a dry film having a thickness dimension of 10 μm is produced from the photosensitive composition, the light transmittance at wavelengths of 450 to 800 nm is 85% or more. The maximum absorbance value of the dried film in the wavelength range of 250 to 800 nm is in the wavelength range of 300 to 330 nm, and the maximum absorbance value is 1 or more.

The photosensitive resin (A) has an ethylenically unsaturated group and a carboxyl group, so that the photosensitive composition has photosensitivity and can be developed using an alkaline solution or the like. In addition, the number average molecular weight Mn of the photosensitive resin (A) is 500 to 2500, and the polydispersity Mw/Mn is 1.2 to 2.8, so that the dried film made from the photosensitive composition is less likely to have tack, and the insulation reliability and plating resistance of the cured product of the photosensitive composition are less likely to be impaired, and the photosensitive composition can have excellent developability. That is, the polydispersity Mw/Mn of the photosensitive composition is 1.2 or more, and the number average molecular weight Mn is 500 or more, so that the dried film is less likely to have tack, and the insulation reliability and plating resistance are less likely to be impaired, and the polydispersity Mw/Mn is 2.8 or less, and the number average molecular weight Mn is 2500 or less, so that the developability with an alkaline aqueous solution is easily improved.

Furthermore, when the acid value of the photosensitive resin (A) is 55 mgKOH/g or more and 130 mgKOH/g or less, the resolution of the cured product produced from the photosensitive composition is particularly likely to be improved.

When a dry film having a thickness of 10 μm is produced from the photosensitive composition, the light transmittance at wavelengths of 450 to 800 nm is 85% or more, so that a highly transparent cured film can be produced from the photosensitive composition. In addition, the maximum absorbance in the wavelength range of 250 to 800 nm in the dry film is in the wavelength range of 300 to 330 nm, and the maximum absorbance is 1 or more, so that the resolution is more likely to be improved. The reason for this is presumed to be as follows. Light in the wavelength range of 300 to 330 nm in ultraviolet light does not easily reach the bottom (deep part) of a dry film containing organic matter, and when the energy of light in the wavelength range (300 to 330 nm) is used for photocuring the dry film, the resolution is likely to decrease. However, if the maximum absorbance of the dried film of the photosensitive composition of this embodiment is in the wavelength range of 300 to 330 nm, the photosensitive resin (A) absorbs light in this wavelength range (300 to 330 nm) and it is difficult to use it for photocuring, which is thought to make it difficult for the resolution of the cured product to decrease. Moreover, in this embodiment, the dry film absorbs little visible light, so there is no loss of transparency, and light with a longer wavelength than the wavelength of the maximum absorbance of the dry film can be used for the curing reaction, so the curing of the photosensitive composition is less likely to be inhibited.

As a result, the cured product produced from the photosensitive composition according to this embodiment can improve resolution while maintaining transparency and curability.

The components that may be contained in the photosensitive composition according to this embodiment are described in detail below.

As described above, photosensitive resin (A) contains photosensitive resin (A1). The synthesis of photosensitive resin (A1) will be described.

The product (hereinafter also referred to as "product (X)") produced by the reaction of epoxy compound (a1) with carboxylic acid (a2) contains product (X1) produced by the reaction of each of the two epoxy groups in epoxy compound (a1) with the carboxyl group in carboxylic acid (a2). This product (X1) has a secondary hydroxyl group produced by the reaction of the epoxy group with the carboxyl group and an ethylenically unsaturated group derived from carboxylic acid (a2). Product (X) may also contain product (X2) produced by the reaction of only one of the two epoxy groups in epoxy compound (a1) with the carboxyl group in carboxylic acid (a2). Product (X2) has a secondary hydroxyl group, an ethylenically unsaturated group, and an epoxy group. Product (X) may also contain unreacted epoxy compound (a1). That is, product (X) may contain a component having an epoxy group, and this component may include at least one of product (X2) and epoxy compound (a1).

The photosensitive resin (A1) produced by the reaction of the product (X) with the acid anhydride (a3) contains the component (X3) produced by the reaction of the product (X1) with the acid dianhydride (a4). The component (X3) has a carboxyl group derived from the acid dianhydride (a4). In addition, since a crosslinking reaction may occur due to the acid dianhydride (a4), the component (X3) is likely to have a molecular weight distribution. In addition, the photosensitive resin (A1) may also contain unreacted product (X1).

Furthermore, the acid anhydride (a3) may contain an acid monoanhydride (a5). Thus, the photosensitive resin (A1) produced by the reaction of the product (X) with the acid anhydride (a3) contains the component (X4) produced by the reaction of the product (X1) with the acid monoanhydride (a5). The component (X4) has a carboxyl group derived from the acid monoanhydride (a5).

This allows the photosensitive resin (A1) to have an appropriate molecular weight distribution. Therefore, a photosensitive resin (A1) having the desired molecular weight and polydispersity can be easily obtained. That is, a photosensitive resin (A1) having a number average molecular weight Mn of 500 or more and 2500 or less and a polydispersity Mw/Mn in the range of 1.2 or more and 2.8 or less can be obtained.

It is preferable that the photosensitive resin (A) contains a resin having an epoxy group. When the photosensitive resin (A) contains a resin having an epoxy group, it can have reactivity with the remaining carboxyl groups in the photosensitive composition. Therefore, the photosensitive composition can exhibit thermosetting properties.

The photosensitive resin (A1) has an ethylenically unsaturated group derived from the carboxylic acid (a2) having an ethylenically unsaturated group, and therefore has photoreactivity. Therefore, the photosensitive resin (A1) can impart photosensitivity (specifically, ultraviolet curing) to the photosensitive composition. In addition, the photosensitive resin (A1) has a carboxyl group derived from the acid anhydride (a3), and therefore can impart developability to the photosensitive composition using an alkaline aqueous solution containing at least one of an alkali metal salt and an alkali metal hydroxide. Furthermore, when the acid anhydride (a3) contains the acid dianhydride (a4), the molecular weight of the photosensitive resin (A1) depends on the number of crosslinks by the acid dianhydride (a4). Therefore, a photosensitive resin (A1) with an appropriately adjusted acid value and molecular weight can be obtained. In addition, when the acid anhydride (a3) contains the acid dianhydride (a4), the amount of the acid dianhydride (a4) can be controlled to easily obtain a photosensitive resin (A1) with a desired molecular weight and acid value.

The number average molecular weight of the photosensitive resin (A1) is preferably 500 or more and 2500 or less. In this case, the developability of the photosensitive composition with an alkaline aqueous solution is likely to be improved. The number average molecular weight is more preferably 800 or more and 2300 or less, even more preferably 900 or more and 2200 or less, and particularly preferably 1000 or more and 2000 or less.

The polydispersity Mw/Mn of the photosensitive resin (A1) is preferably 1.2 or more and 2.8 or less. The polydispersity Mw/Mn of the photosensitive resin (A1) is more preferably 1.3 or more and 2.7 or less, even more preferably 1.4 or more and 2.6 or less, and particularly preferably 1.5 or more and 2.5 or less. Note that the polydispersity is the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the photosensitive resin (A1).

The number average molecular weight (Mn) and weight average molecular weight (Mw) of the photosensitive resin (A1) are calculated from the molecular weight measurement results by gel permeation chromatography. The molecular weight measurement by gel permeation chromatography can be performed, for example, under the following conditions.

GPC device: Showa Denko SHODEX SYSTEM 11,
Column: SHODEX KF-800P, KF-005, KF-003, KF-001, four columns in series;
Mobile phase: THF,
Flow rate: 1ml/min,
Column temperature: 45°C,
Detector: RI,
Conversion: Polystyrene.

The acid value of the photosensitive resin (A1) is preferably 55 mgKOH/g or more and 130 mgKOH/g or less. In this case, the resolution of the cured product produced from the photosensitive composition is particularly improved. The acid value of the photosensitive resin (A1) is more preferably 60 mgKOH/g or more and 120 mgKOH/g or less, even more preferably 60 mgKOH/g or more and 110 mgKOH/g or less, and particularly preferably 60 mgKOH/g or more and less than 75 mgKOH/g.

The raw materials for photosensitive resin (A1) and the reaction conditions for synthesizing photosensitive resin (A1) are explained in detail below.

The epoxy compound (a1) having at least two epoxy groups can contain, for example, a compound having a bisphenolfluorene skeleton. The photosensitive resin (A1) is, for example, a reaction product of an epoxy compound having a bisphenolfluorene skeleton represented by the following formula (1) and a carboxylic acid (a2) having an ethylenically unsaturated group, and an acid anhydride (a3). That is, the photosensitive resin (A1) is synthesized by reacting an epoxy compound having a bisphenolfluorene skeleton represented by the following formula (1) with a carboxylic acid (a2) having an ethylenically unsaturated group, and reacting the product obtained thereby with an acid anhydride (a3). When the photosensitive composition contains the photosensitive resin (A1), the cured product of the photosensitive composition can have high heat resistance and insulation reliability. In addition, when the photosensitive resin (A1) has a bisphenolfluorene skeleton, it is easy to absorb light in the wavelength range of 300 to 330 nm, so the resolution of the cured product produced from the photosensitive composition can be improved. In addition, when the photosensitive resin (A1) has a bisphenolfluorene skeleton, it has a bulky structure, so it is possible to prevent the diffusion of the generated radical species, and the resolution of the cured product produced from the photosensitive composition can be improved even when exposed to light that does not have a wavelength range of 300 to 330 nm.

Each of R ₁ to R ₈ in formula (1) may be hydrogen, an alkyl group having 1 to 5 carbon atoms, or a halogen. This is because even if hydrogen in the aromatic ring is replaced with a low-molecular-weight alkyl group or a halogen, there is no adverse effect on the physical properties of the carboxyl group-containing resin (A1), and rather, the heat resistance or flame retardancy of the cured product of the photosensitive composition containing the carboxyl group-containing resin (A1) may be improved.

The epoxy compound (a1) may have a structure shown in the following formula (2), for example. In formula (2), n is, for example, an integer in the range of 0 to 20. In order to appropriately control the molecular weight of the carboxyl group-containing resin (A1), it is particularly preferable that the average of n is in the range of 0 to 1. If the average of n is in the range of 0 to 1, even when the acid anhydride (a3) contains an acid dianhydride, an excessive increase in molecular weight is easily suppressed. In addition, in formula (2), R ₁ to R ₈ are each independently hydrogen, an alkyl group having 1 to 5 carbon atoms, or a halogen.

The carboxylic acid (a2) having an ethylenically unsaturated group can contain, for example, a compound having only one ethylenically unsaturated group in one molecule. More specifically, the carboxylic acid (a2) having an ethylenically unsaturated group can contain at least one compound selected from the group consisting of, for example, 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 carboxylic acid (a2) having an ethylenically unsaturated group contains acrylic acid.

When reacting the epoxy compound (a1) with the carboxylic acid (a2), an appropriate method can be adopted. For example, a reactive solution is obtained by adding the carboxylic acid (a2) to a solvent solution of the epoxy compound (a1), and further adding a thermal polymerization inhibitor and a catalyst as necessary, and stirring and mixing. The reactive solution is reacted by a conventional method, preferably at a temperature of 60°C to 150°C, particularly preferably at a temperature of 80°C to 120°C, to obtain the product (X). The solvent in this case can contain at least one component selected from the group consisting of ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, and acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, and propylene glycol monomethyl ether acetate, and dialkyl glycol ethers. The thermal polymerization inhibitor contains at least one of hydroquinone and hydroquinone monomethyl ether, for example. The catalyst may contain at least one component selected from the group consisting of tertiary amines such as benzyldimethylamine and triethylamine, quaternary ammonium salts such as trimethylbenzylammonium chloride and methyltriethylammonium chloride, triphenylphosphine, and triphenylstibine.

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

When the epoxy compound (a1) and the carboxylic acid (a2) are reacted, the amount of the carboxylic acid (a2) per mole of the epoxy group of the epoxy compound (a1) is preferably 0.7 moles or more and 1.0 moles or less. In this case, a photosensitive composition having excellent photosensitivity and stability is obtained.

The product (X) thus obtained has a hydroxyl group produced by the reaction between the epoxy group of the epoxy compound (a1) and the carboxyl group of the carboxylic acid (a2).

The acid dianhydride (a4) is a compound having two acid anhydride groups. The acid dianhydride (a4) can contain an anhydride of a tetracarboxylic acid. Examples of the acid dianhydride (a4) include 1,2,4,5-benzenetetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, methylcyclohexene tetracarboxylic dianhydride, tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, ethylene tetracarboxylic dianhydride, 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, glycerin bis(anhydrotrimellitate) monoacetate, ethylene It may contain at least one compound selected from the group consisting of glycol bisanhydrotrimellitate, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione, 1,2,3,4-butanetetracarboxylic dianhydride, and 3,3',4,4'-biphenyltetracarboxylic dianhydride. In particular, it is preferable that the acid dianhydride (a4) contains 3,3',4,4'-biphenyltetracarboxylic dianhydride. In this case, while ensuring good developability of the photosensitive composition, the tackiness of the film produced from the photosensitive composition can be further suppressed and the insulation reliability and plating resistance of the cured product can be further improved.

The acid anhydride (a3) may contain an acid monoanhydride (a5). The acid monoanhydride (a5) is a compound having one acid anhydride group. The acid monoanhydride (a5) may contain an anhydride of a dicarboxylic acid. The acid monoanhydride (a5) may contain at least one compound selected from the group consisting of, for example, 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. In this case, while ensuring good developability of the photosensitive composition, the tackiness of the film made from the photosensitive composition can be further suppressed, and the insulating reliability and plating resistance of the cured product can be further improved.

When reacting the product (X) with the acid anhydride (a3), an appropriate method can be adopted. For example, the acid anhydride (a3) is added to a solvent solution of the product (X), and if necessary, a thermal polymerization inhibitor and a catalyst are added and mixed by stirring to obtain a reactive solution. The reactive solution is reacted by a conventional method at a temperature preferably from 60°C to 150°C, particularly preferably from 80°C to 120°C, to obtain the photosensitive resin (A1). As the solvent, catalyst, and polymerization inhibitor, appropriate ones can be used, and the solvent, catalyst, and polymerization inhibitor used in the synthesis of the product (X) can also be used as they are.

The catalyst preferably contains triphenylphosphine. That is, it is preferable to react the product (X) with the acid anhydride (a3) in the presence of triphenylphosphine. In this case, the reaction between the secondary hydroxyl group in the product (X) and the acid anhydride (a3) is particularly promoted, and a reaction rate (conversion rate) of 90% or more, 95% or more, 97% or more, or nearly 100% can be achieved.

When the acid anhydride (a3) contains the acid dianhydride (a4), the amount of the acid dianhydride (a4) is preferably 0.01 mol or more and 0.24 mol or less per 1 mol of the epoxy group of the epoxy compound (a1). In this case, a photosensitive resin (A1) with an appropriately adjusted acid value and molecular weight can be easily obtained. The amount of the acid dianhydride (a4) is more preferably 0.04 mol or more and 0.22 mol or less.

When the acid anhydride (a3) further contains an acid monoanhydride (a5), the amount of the acid monoanhydride (a5) is preferably 0.05 mol or more and 0.7 mol or less per 1 mol of the epoxy group of the epoxy compound (a1). In this case, a photosensitive resin (A1) with an appropriately adjusted acid value and molecular weight can be easily obtained.

It is also preferable to react the product (X) with the acid anhydride (a3) under air bubbling. In this case, excessive increase in the molecular weight of the photosensitive resin (A1) produced is suppressed, and the developability of the photosensitive composition with an alkaline aqueous solution is particularly improved.

The components other than the photosensitive resin (A1) in the photosensitive composition are described below.

As already mentioned, the photosensitive composition contains, for example, a photosensitive resin (A) containing a resin having an ethylenically unsaturated group and a carboxyl group, a photopolymerization initiator (B), and a photopolymerizable compound (C).

The photosensitive resin (A) may contain only the photosensitive resin (A1), or may contain a photosensitive resin (A2) other than the photosensitive resin (A1). The photosensitive resin (A2) contains, for example, a resin that is a reaction product between 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 without a carboxyl group. The photosensitive resin (A2) is obtained by reacting an ethylenically unsaturated compound having an epoxy group with a part of the carboxyl group in the polymer. The ethylenically unsaturated monomer may further contain an ethylenically unsaturated compound without a carboxyl group. The ethylenically unsaturated compound having a carboxyl group contains, for example, compounds such as acrylic acid, methacrylic acid, ω-carboxy-polycaprolactone (n≒2) monoacrylate, pentaerythritol triacrylate, and pentaerythritol trimethacrylate. Ethylenically unsaturated compounds without a carboxyl group include, for example, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, linear or branched aliphatic or alicyclic (which may have some unsaturated bonds in the ring) (meth)acrylic acid esters, etc. Ethylenically unsaturated compounds with an epoxy group preferably include glycidyl (meth)acrylate.

The photopolymerization initiator (B) is a component that can improve the photosensitivity of the photosensitive composition. The photopolymerization initiator (B) preferably contains at least one selected from the group consisting of, for example, an α-aminoalkylphenone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and an oxime ester-based photopolymerization initiator. In this case, when the photosensitive composition is exposed to light such as ultraviolet light, high photosensitivity can be imparted to the photosensitive composition. It is further preferable that the photopolymerization initiator (B) contains an acylphosphine oxide-based photopolymerization initiator. In this case, high photosensitivity can be imparted to the photosensitive composition, and high transparency can be maintained with little coloring.

The α-aminoalkylphenone photopolymerization initiator can contain at least one component selected from the group consisting of, for example, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone.

Examples of acylphosphine oxide photopolymerization initiators include monoacylphosphine oxide photopolymerization initiators such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and 2,4,6-trimethylbenzoyl-ethyl-phenyl-phosphinate, as well as bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, and bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide. It can contain at least one component selected from the group consisting of bisacylphosphine oxide-based photopolymerization initiators such as bisacylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide.

The oxime ester photopolymerization initiator may contain at least one component selected from the group consisting of, for example, 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, and 1-(O-acetyloxime).

The photosensitive composition may further contain an appropriate photopolymerization accelerator, a sensitizer, and the like. For example, the photosensitive composition may contain hydroxyketones such as 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; benzoin and its alkyl ethers; acetophenones such as acetophenone and benzyl dimethyl ketal; anthraquinones such as 2-methylanthraquinone; 2,4-dimethyl The photosensitive composition may contain at least one component selected from the group consisting of thioxanthones such as thioxanthone, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, and 2,4-diisopropylthioxanthone; benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and bis(diethylamino)benzophenone; xanthones such as 2,4-diisopropylxanthone; and α-hydroxyketones such as 2-hydroxy-2-methyl-1-phenyl-propan-1-one; and compounds containing a nitrogen atom such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone. The photosensitive composition may contain, together with the photopolymerization initiator (B), an appropriate photopolymerization accelerator and sensitizer, such as a tertiary amine such as p-dimethylbenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ester, and 2-dimethylaminoethyl benzoate. The photosensitive composition may contain at least one of a photopolymerization initiator for visible light exposure and a photopolymerization initiator for near-infrared light exposure, as necessary. The photosensitive adhesive composition may contain, together with the photopolymerization initiator (B), a coumarin derivative such as 7-diethylamino-4-methylcoumarin, which is a sensitizer for laser exposure, a carbocyanine dye, a xanthene dye, or the like.

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

The photopolymerizable prepolymer may contain at least one compound selected from the group consisting of 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 prepolymers may contain at least one component selected from the group consisting of epoxy(meth)acrylate, polyester(meth)acrylate, urethane(meth)acrylate, alkyd resin(meth)acrylate, silicone resin(meth)acrylate, and spiran resin(meth)acrylate.

In particular, the photopolymerizable compound (C) preferably contains at least one of a bifunctional unsaturated compound and a trifunctional unsaturated compound, i.e., at least one of a compound having two unsaturated bonds in one molecule or a compound having three unsaturated bonds in one molecule. In this case, the resolution is improved when a dried film made from the photosensitive composition is exposed and developed, and the developability of the photosensitive composition with an alkaline aqueous solution is particularly improved.

It is preferable that the photosensitive composition further contains an epoxy compound (D). In this case, the photosensitive composition can be given thermosetting properties. In addition, in this case, the plating resistance and insulating properties of the cured product produced from the photosensitive composition can be improved.

The epoxy compound (D) may contain, for example, a crystalline epoxy resin (D1). The epoxy compound (D) may further contain an amorphous epoxy resin (D2). Here, a "crystalline epoxy resin" is an epoxy resin that has a melting point, and an "amorphous epoxy resin" is an epoxy resin that does not have a melting point.

The crystalline epoxy resin (D1) preferably contains one or more components selected from the group consisting of, for example, 1,3,5-tris(2,3-epoxypropyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, hydroquinone-type crystalline epoxy resin (specifically, Nippon Steel & Sumikin Chemical Co., Ltd., product name YDC-1312), biphenyl-type crystalline epoxy resin (specifically, Mitsubishi Chemical Co., Ltd., product name YX-4000), diphenyl ether-type crystalline epoxy resin (specifically, Nippon Steel Chemical & Material Co., Ltd., product name YSLV-80DE), bisphenol-type crystalline epoxy resin (specifically, Nippon Steel & Sumikin Chemical Co., Ltd., product name YSLV-80XY), tetrakisphenolethane-type crystalline epoxy resin (specifically, Nippon Kayaku Co., Ltd., product name GTR-1800), and bisphenolfluorene-type crystalline epoxy resin (specifically, epoxy resin having structure (S7)).

It is preferable that the crystalline epoxy resin (D1) has two epoxy groups per molecule. In this case, it is possible to make it even more difficult for cracks to occur in the cured product when temperature changes are repeated.

The crystalline epoxy resin (D1) preferably has an epoxy equivalent of 150 g/eq or more and 300 g/eq or less. This epoxy equivalent is the gram weight of the crystalline epoxy resin (D1) containing 1 gram equivalent of epoxy groups. The crystalline epoxy resin (D1) has a melting point. The melting point of the crystalline epoxy resin (D1) is, for example, 70°C or more and 180°C or less.

In particular, the epoxy compound (D) preferably contains a crystalline epoxy resin (D1-1) having a melting point of 110°C or less. In this case, the developability of the photosensitive agent composition with an alkaline aqueous solution is particularly improved. In this case, the resolution (opening ability) of the cured layer produced from the photosensitive composition can also be improved. The crystalline epoxy resin (D1-1) having a melting point of 110°C or less can contain at least one component selected from the group consisting of, for example, biphenyl type epoxy resin (specific example: product number YX-4000 manufactured by Mitsubishi Chemical Corporation), biphenyl ether type epoxy resin (specific example: product number YSLV-80DE manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), bisphenol type epoxy resin (specific example: product number YSLV-80XY manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), and bisphenol fluorene type crystalline epoxy resin (specific example: epoxy resin having structure (S7)).

Examples of the amorphous epoxy resin (D2) include phenol novolac type epoxy resins (specifically, EPICLON N-775 manufactured by DIC Corporation), cresol novolac type epoxy resins (specifically, EPICLON N-695 manufactured by DIC Corporation), bisphenol A novolac type epoxy resins (specifically, EPICLON N-865 manufactured by DIC Corporation), bisphenol A type epoxy resins (specifically, jER1001 manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resins (specifically, jER4004P manufactured by Mitsubishi Chemical Corporation), bisphenol S type epoxy resins (specifically, EPICLON N-865 manufactured by DIC Corporation), and the like. EXA-1514), bisphenol AD type epoxy resin, biphenyl novolac type epoxy resin (specific example is product number NC-3000 manufactured by Nippon Kayaku Co., Ltd.), hydrogenated bisphenol A type epoxy resin (specific example is product number ST-4000D manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), naphthalene type epoxy resin (specific examples are product numbers EPICLON HP-4032, EPICLON HP-4700, EPICLON HP-4770 manufactured by DIC Corporation), tertiary butyl catechol type epoxy resin (specific example is product number EPICLON HP-820 manufactured by DIC Corporation), dicyclopentadiene type epoxy resin (specific example is product number EPICLON HP-820 manufactured by DIC Corporation), HP-7200), adamantane type epoxy resins (specific examples include ADAMANTATEX-E-201, manufactured by Idemitsu Kosan Co., Ltd.), special bifunctional epoxy resins (specific examples include YL7175-500 and YL7175-1000, manufactured by Mitsubishi Chemical Corporation; EPICLON TSR-960, EPICLON TER-601, EPILON TSR-250-80BX, EPICLON 1650-75MPX, EPICLON EXA-4850, EPICLON EXA-4816, EPICLON EXA-4822, and EPICLON EXA-4832, manufactured by DIC Corporation), EXA-9726; product number YSLV-120TE manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), rubber-like core-shell polymer modified bisphenol A type epoxy resin (specific example is product number MX-156 manufactured by Kaneka Corporation), rubber-like core-shell polymer modified bisphenol F type epoxy resin (specific example is product number MX-136 manufactured by Kaneka Corporation), and rubber particle-containing bisphenol F type epoxy resin (specific example is product number Kane Ace MX-130 manufactured by Kaneka Corporation).

When the photosensitive composition contains an epoxy compound (D), it is preferable that the photosensitive composition contains both a crystalline epoxy resin (D1) and an amorphous epoxy resin (D2). In this case, the plating resistance and insulating properties of the cured product produced from the photosensitive composition can be further improved.

The epoxy compound (D) may contain a phosphorus-containing epoxy resin. In this case, the flame retardancy of the cured product of the photosensitive composition is improved. The phosphorus-containing epoxy resin may be contained in the crystalline epoxy resin (D1) or in the amorphous epoxy resin (D2). Examples of the phosphorus-containing epoxy resin include phosphoric acid-modified bisphenol F type epoxy resin (specific examples are EPICLON EXA-9726 and EPICLON EXA-9710 manufactured by DIC Corporation), Epotohto FX-305 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., etc.

The epoxy compound (D) may contain an epoxy compound (D3) having a bisphenolfluorene skeleton. This epoxy compound (D3) includes, for example, an epoxy compound (a1) having a bisphenolfluorene skeleton (S1) represented by the formula (1) described above.

The photosensitive composition preferably contains a solvent (E). The solvent (E) may contain at least one compound selected from the group consisting of water, ethanol, isobutanol, 1-butanol, isopropanol, hexanol, ethylene glycol, 3-methyl-3-methoxybutanol, and other linear, branched, secondary, or polyhydric alcohols; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; petroleum-based aromatic mixed solvents such as the Swasol series (manufactured by Maruzen Petrochemical Co., Ltd.) and the Solvesso series (manufactured by Exxon Chemical Co., Ltd.); cellosolves such as cellosolve and butyl cellosolve; carbitols such as carbitol and butyl carbitol; alkylene glycol alkyl ethers such as ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, and propylene glycol methyl ether; polypropylene glycol alkyl ethers such as dipropylene glycol methyl ether; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, and carbitol acetate; and dialkyl glycol ethers. The solvent (E) preferably contains at least one alcohol-based solvent (E1) selected from the group consisting of polypropylene glycol alkyl ethers such as propylene glycol monomethyl ether, ethanol, isobutanol, 1-butanol, isopropanol, hexanol, ethylene glycol, 3-methyl-3-methoxybutanol, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol methyl ether, and dipropylene glycol methyl ether. That is, the photosensitive composition preferably contains an alcohol-based solvent (E1). In this case, the coatability and uniformity of the photosensitive composition can be further improved when preparing the photosensitive composition. In addition, even when a thermoplastic film is used as the substrate, the substrate is less likely to be dissolved, and the substrate is less likely to be damaged. The solvent (E) more preferably contains propylene glycol monomethyl ether. In this case, the coatability and uniformity of the photosensitive composition can be further improved, and good drying properties can also be obtained. It is more preferable that the propylene glycol monomethyl ether is contained in a ratio of 50% by mass or more relative to the solvent (E).

The amounts of the components in the photosensitive composition are appropriately adjusted so that the photosensitive composition is photocurable and developable in an alkaline solution.

The amount of photosensitive resin (A) relative to the solid content of the photosensitive composition is preferably 50% by mass or more and 90% by mass or less, more preferably 55% by mass or more and 85% by mass or less, and even more preferably 60% by mass or more and 80% by mass or less. The amount of photosensitive resin (A1) relative to the solid content of the photosensitive composition is preferably 50% by mass or more and 90% by mass or less, more preferably 55% by mass or more and 85% by mass or less, and even more preferably 60% by mass or more and 80% by mass or less.

The amount of photopolymerization initiator (B) relative to the photosensitive resin (A) is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less.

The amount of the photopolymerizable compound (C) relative to the photosensitive resin (A) is preferably 5% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and even more preferably 25% by mass or more and 45% by mass or less.

When the photosensitive composition contains an epoxy compound (D), the amount of the epoxy compound (D) is preferably such that the total equivalent of the epoxy groups contained in the epoxy compound (D) is more than 0 equivalents and not more than 2 equivalents relative to 1 equivalent of the carboxyl groups contained in the photosensitive resin (A), more preferably more than 0 equivalents and not more than 1 equivalent, and even more preferably more than 0 equivalents and not more than 0.5 equivalents.

When the photosensitive composition contains a solvent (E), the amount of the solvent (E) is preferably 50% by mass or more and 95% by mass or less based on the total amount of the photosensitive composition. In this case, the coatability of the photosensitive composition can be improved when the photosensitive composition is applied.

The photosensitive composition may further contain components other than those described above, as long as they do not impair the effects of this embodiment.

The photosensitive composition may contain at least one resin selected from the group consisting of blocked isocyanates of the tolylene diisocyanate type, morpholine diisocyanate type, isophorone diisocyanate type, and hexamethylene diisocyanate type blocked with caprolactam, oxime, malonic acid ester, etc.; butylated urea resin; various thermosetting resins other than those mentioned 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, and alicyclic type; and polymer compounds such as diallyl phthalate resin, phenoxy resin, urethane resin, and fluororesin.

The photosensitive composition may contain a curing agent for curing the epoxy compound (D). The curing agent may contain at least one component selected from the group consisting of imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; 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 adipic acid hydrazide and sebacic acid hydrazide; phosphorus compounds such as triphenylphosphine; acid anhydrides; phenols; mercaptans; Lewis acid amine complexes; and onium salts. Commercially available products of these components include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names of imidazole-based compounds) manufactured by Shikoku Kasei Co., Ltd., and U-CAT3503N and UCAT3502T (all trade names of dimethylamine blocked isocyanate compounds), DBU, DBN, U-CATSA102, and U-CAT5002 (all bicyclic amidine compounds and their salts) manufactured by San-Apro Co., Ltd.

The photosensitive composition may contain an adhesion imparting agent. Examples of adhesion imparting agents 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), as well as S-triazine derivatives such as 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-4,6-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine-isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine-isocyanuric acid adduct, and silane coupling agents.

The photosensitive composition may contain a rheology control agent. The rheology control agent makes it easier to optimize the viscosity of the photosensitive composition. Examples of rheology control agents include urea-modified medium polarity polyamide (product numbers BYK-430 and BYK-431 manufactured by BIGBANG), polyhydroxycarboxylic acid amide (product number BYK-405 manufactured by BIGBANG), modified urea (product numbers BYK-410, BYK-411, and BYK-420 manufactured by BIGBANG), polymeric urea derivative (product number BYK-415 manufactured by BIGBANG), urea-modified urethane (product number BYK-425 manufactured by BIGBANG), polyurethane (product number BYK-428 manufactured by BIGBANG), castor oil wax, polyethylene wax, polyamide wax, bentonite, kaolin, and clay.

The photosensitive composition may contain at least one component selected from the group consisting of a curing accelerator; a colorant; a copolymer of silicone, acrylate, or the like; a leveling agent; a thixotropic agent; a polymerization inhibitor; an antihalation agent; a flame retardant; an antifoaming agent; an antioxidant; a surfactant; and a polymer dispersant.

The photosensitive composition of this embodiment may be prepared by any suitable method. For example, the photosensitive composition may be prepared by mixing and stirring the raw materials of the photosensitive composition. The photosensitive composition may also be prepared by kneading the raw materials by a suitable kneading method using, for example, a three-roll mill, a ball mill, a sand mill, or the like. When the raw materials contain liquid components, low-viscosity components, etc., the raw materials may be kneaded first to prepare a mixture, except for the liquid components, low-viscosity components, etc., and then the liquid components, low-viscosity components, etc. may be added to the obtained mixture and mixed to prepare the photosensitive composition. When the photosensitive composition contains a solvent (E), first, part or all of the solvent may be mixed among the raw materials, and then mixed with the remaining raw materials.

The photosensitive composition of this embodiment has a light transmittance of 85% or more at wavelengths of 450 to 800 nm when a dry film having a thickness of 10 μm is produced from this photosensitive composition. This allows a highly transparent cured film to be obtained, which is particularly suitable for optical applications. The absorption spectrum of the dry film produced from the photosensitive composition is measured by a spectrophotometer or other spectrophotometer. The specific measurement method can be similar to the evaluation tests (4-1) and (4-2) in the examples described below. By measuring the absorption spectrum of the dry film produced from the photosensitive composition, the light transmittance and absorbance can be obtained. When a dry film having a thickness of 10 μm is produced from the photosensitive composition, it is more preferable that the light transmittance at wavelengths of 450 to 800 nm is 90% or more. In addition, the maximum absorbance in the wavelength range of 250 to 800 nm is in the wavelength range of 300 to 330 nm, and the maximum absorbance in the wavelength range of 300 to 330 nm is 1 or more. This can further improve the resolution of the cured product produced from the photosensitive composition. The maximum absorbance is more preferably 1.2 or more, and even more preferably 1.5 or more. Note that the above "dry film having a thickness dimension of 10 μm" does not mean that the thickness of the dry film produced from the photosensitive composition of this embodiment is limited to 10 μm.

The photosensitive composition according to this embodiment is suitable as a material for electrically insulating layers such as solder resist layers, interlayer insulating layers, and plating resist layers. In particular, as described above, the photosensitive composition has high transparency while also having high developability, making it suitable as an electrically insulating material for optical applications.

The photosensitive composition according to this embodiment preferably has properties such that even a film having a thickness of 25 μm can be developed with an aqueous sodium carbonate solution. In this case, since a sufficiently thick electrically insulating layer can be produced from the photosensitive composition by photolithography, the photosensitive composition can be widely applied to produce interlayer insulating layers, solder resist layers, and the like in printed wiring boards. Of course, it is also possible to produce electrically insulating layers having a thickness less than 25 μm from the photosensitive composition.

Whether or not a 25 μm thick film can be developed with an aqueous sodium carbonate solution can be confirmed by the following method. A wet coating film is prepared by applying a photosensitive composition onto a suitable substrate, and the wet coating film is heated at 80° C. for 40 minutes to form a 25 μm thick film. In a state where a negative mask having an exposed portion that transmits ultraviolet light and a non-exposed portion that blocks ultraviolet light is directly applied to the film, the film is exposed to ultraviolet light under the condition of 500 mJ/cm ^2. After exposure, a process is performed in which a 1% Na ₂ CO ₃ aqueous solution at 30° C. is sprayed onto the film at a spray pressure of 0.2 MPa for 90 seconds, and then pure water is sprayed at a spray pressure of 0.2 MPa for 90 seconds. When the film is observed after this process, if the portion corresponding to the non-exposed portion of the film is removed and no residue is found, it can be determined that the 25 μm thick film can be developed with an aqueous sodium carbonate solution. It is also possible to confirm whether or not a film of another thickness (e.g., 30 μm) can be developed with an aqueous sodium carbonate solution in the same manner.

Next, the laminate 10 according to this embodiment will be described with reference to Figures 1A and 1B.

The laminate 10 comprises a substrate 1 and a transparent cured film 40 overlying the substrate 1. The transparent cured film 40 contains the cured product of the photosensitive composition described above. Since the laminate 10 comprises the transparent cured film 40, it is suitable for optical applications.

The substrate 1 may be any suitable substrate such as glass, plastic, or ceramic. More specifically, the substrate 1 may include a film made of a thermoplastic resin such as polyethylene terephthalate, cycloolefin polymer, liquid crystal polymer, or polycarbonate. The substrate 1 may also be a substrate having an insulating layer 2 and conductor wiring 3 on the insulating layer 2 (see FIG. 2A).

As already mentioned, the transparent cured film 40 includes a cured product of the photosensitive composition. Therefore, the transparent cured film 40 can also be used as a plating resist. Therefore, the laminate 10 may have a plating layer such as hole plating 8. Specifically, the laminate 10 may have hole plating 8 by performing a plating process on the gaps in the cured product (transparent cured film 40) that is produced by, for example, applying a photosensitive composition to the substrate 1 to produce a coating film, and exposing and developing the coating film of the photosensitive composition by photolithography or the like (see FIG. 1B).

The laminate 10 is not limited to the configuration shown in Figures 1A and 1B, and may have, for example, a layer between the substrate 1 and the transparent cured film 40 that is different from the substrate 1 and the transparent cured film 40.

The laminate 10 according to this embodiment can be produced, for example, as follows.

The laminate 10 is produced by applying a photosensitive composition onto the substrate 1 to produce a dry film having a thickness of 10 μm or less, partially exposing the dry film to light, and then developing it with an alkaline developer to form a pattern, thereby producing a transparent cured film 40 that overlays the substrate 1. This produces a laminate 10 that includes the substrate 1 and the transparent cured film 40 that overlays the substrate 1.

The manufacturing method of the laminate 10 will be explained in more detail with an example, referring to Figures 2A to 2E.

First, a substrate 1 is prepared as shown in FIG. 2A. In FIG. 2A, the substrate 1 includes at least one insulating layer 2 and at least one conductor wiring 3, but is not limited thereto, and the substrate 1 may be, for example, a film material made of a thermoplastic resin. In the following, as an example, a case where the substrate 1 includes an insulating layer 2 and a conductor wiring 3 will be described. In addition, the conductor wiring 3 provided on the substrate 1 will be referred to as a first conductor wiring 31.

Next, as shown in FIG. 2B, a coating 4 is formed from a photosensitive composition on one surface of the substrate 1. The coating 4 can be formed, for example, by a coating method or a dry film method.

In the coating method, for example, a photosensitive composition is applied onto a substrate 1 to form a wet coating film. The method for applying the photosensitive composition is selected from the group consisting of known methods, for example, immersion, spraying, spin coating, roll coating, curtain coating, and screen printing. Next, the wet coating film is dried at a temperature in the range of, for example, 60 to 130°C to volatilize the organic solvent in the photosensitive composition, thereby obtaining a coating film 4.

In the dry film method, a photosensitive composition is first applied to a suitable support made of polyester or the like, and then dried to form a dry film, which is a dried product of the photosensitive composition, on the support. This results in a dry film with a support, which comprises a dry film and a support that supports the dry film. The dry film in this dry film with a support is overlaid on a substrate 1, pressure is applied to the dry film and substrate 1, and the support is then peeled off from the dry film, transferring the dry film from the support to the substrate 1. This results in a coating 4 made of a dry film being provided on the substrate 1.

By exposing the film 4, the film 4 is partially cured as shown in FIG. 2C. For this purpose, for example, a negative mask is placed on the film 4, and then the film 4 is irradiated with ultraviolet light. The negative mask has an exposed portion that transmits ultraviolet light and a non-exposed portion that blocks ultraviolet light, and the non-exposed portion is provided at a position that matches the position of the through hole 9. The negative mask is, for example, a photo tool such as a mask film or a dry plate. The ultraviolet light source is, for example, selected from the group consisting of 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, an LED, a YAG, a g-line (436 nm), an h-line (405 nm), an i-line (365 nm), and a combination of two or more of the g-line, the h-line, and the i-line. The ultraviolet light source is not limited to these, and may be any light source that can irradiate ultraviolet light that can cure the photosensitive composition.

The exposure method may be a method other than the method using a negative mask. For example, the film 4 may be exposed by a direct writing method in which ultraviolet light emitted from a light source is irradiated only to the portion of the film 4 to be exposed. The light source applied to the direct writing method is selected from the group consisting of, for example, a chemical lamp, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an extra-high pressure mercury lamp, a xenon lamp, a metal halide lamp, an LED, a YAG, g-line (436 nm), h-line (405 nm), i-line (365 nm), and a combination of two or more of g-line, h-line, and i-line. The light source of the ultraviolet light is not limited to these, and may be any light source that can irradiate ultraviolet light capable of curing the photosensitive composition.

In addition, in the dry film method, the dry film in the dry film with support is superimposed on the substrate 1, and then the coating 4 made of the dry film is exposed to ultraviolet light through the support without peeling off the support, and then the support may be peeled off from the coating 4 before the development process.

Then, the film 4 is subjected to a development process to remove the unexposed portion 5 of the film 4 shown in FIG. 2C, thereby forming a hole 6 at the position where the through hole 9 is to be formed as shown in FIG. 2D. In the development process, an appropriate developer can be used according to the composition of the photosensitive composition. The developer is, for example, an alkaline aqueous solution containing at least one of an alkali metal salt and an alkali metal hydroxide, or an organic amine. More specifically, the alkaline aqueous solution contains at least one component selected from the group consisting of 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 at least one component selected from the group consisting of, for example, 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 is particularly preferably an aqueous sodium carbonate solution. In this case, it is possible to improve the working environment and reduce the burden of waste disposal.

This results in a laminate 10 having a transparent cured film 40 containing a cured product of the photosensitive composition on the substrate 1.

The transparent cured film 40 prepared as above may be further subjected to the following treatments.

For example, the transparent cured film 40 may be thermally cured by heating. The heating conditions are, for example, a heating temperature in the range of 80 to 200°C and a heating time in the range of 2 to 120 minutes. In this case, for example, the performance of the interlayer insulating layer formed from the transparent cured film 40, such as strength, hardness, and chemical resistance, is improved. If necessary, the transparent cured film 40 may be further irradiated with ultraviolet light either before or after heating, or both. Alternatively, the transparent cured film 40 may be further irradiated with ultraviolet light without heating. In this case, the photocuring of the transparent cured film 40 can be further promoted.

Furthermore, the transparent cured film 40 may be subjected to a plating process. Any suitable method may be used for the plating process. For example, the second conductor wiring 32 and hole plating 8 may be provided on the transparent cured film 40 in the laminate 10 by a method such as an additive method. In this case, as shown in FIG. 2E, a printed wiring board 11 is obtained that includes the first conductor wiring 31, the second conductor wiring 32, the transparent cured film 40 interposed between the first conductor wiring 31 and the second conductor wiring 32, and a through hole 9 that electrically connects the first conductor wiring 31 and the second conductor wiring 32.

In FIG. 2E, the hole plating 8 has a cylindrical shape that covers the inner surface of the hole 6, but the entire inside of the hole 6 may be filled with the hole plating 8. In providing the hole plating 8, an initial wiring can be formed by subjecting a part of the roughened outer surface described below and the inner surface of the hole 6 to an electroless metal plating process. After that, the hole plating 8 can be formed by depositing metal in an electrolytic plating solution on the initial wiring by an electrolytic metal plating process.

In addition, before the plating process, the transparent cured film 40 may be subjected to a roughening process to roughen the surface of the transparent cured film 40. For example, roughening a part of the outer surface of the transparent cured film 40 and the entire inner surface of the hole 6 can be performed in the same procedure as a general desmear process using an oxidizing agent. For example, an oxidizing agent is brought into contact with the outer surface of the transparent cured film 40 to impart a rough surface to the transparent cured film 40. However, this is not limited to this, and a method that does not impart a rough surface to the cured product, such as a plasma treatment, a corona treatment, a UV treatment, an ozone treatment, or a primer treatment, can also be appropriately adopted. The oxidizing agent may be an oxidizing agent available as a desmear solution. For example, the oxidizing agent may be composed of a commercially available swelling solution for desmear and a desmear solution. Such an oxidizing agent may contain at least one permanganate selected from the group consisting of sodium permanganate and potassium permanganate.

The thickness of the transparent cured film 40 is not particularly limited, but is preferably 0.1 μm or more and 100 μm or less. The thickness of the transparent cured film 40 is more preferably 0.2 μm or more and 50 μm or less, even more preferably 0.3 μm or more and 20 μm or less, and particularly preferably 1 μm or more and 15 μm or less. As already mentioned, the transparent cured film 40 can be suitably used, for example, as an interlayer insulating layer. When the transparent cured film 40 is used as an interlayer insulating layer, in order to ensure high resolution of the interlayer insulating layer, the thickness is preferably 1 μm or more and 25 μm or less, and more preferably in the range of 1 μm or more and 10 μm or less.

As a result, a transparent cured film 40 made of the cured product of the photosensitive composition is formed on the substrate 1.

The photosensitive composition of this embodiment can be used to form particularly effective electrical insulating layers such as plating resist layers, solder resist layers, and interlayer insulating layers from the dried product, that is, a dry film, or from a coating of the photosensitive composition.

Specific examples of the present invention are presented below. However, the present invention is not limited to these examples.

(1) Synthesis of photosensitive resin (1-1) Synthesis example 1 (photosensitive resin A-1)
Into a four-neck flask equipped with a reflux condenser, a thermometer, an air inlet tube, and a stirrer, 252 parts by mass of a bisphenol fluorene type epoxy compound (an epoxy compound represented by formula (2) in which R ₁ to R ₈ in formula (2) are all hydrogen and have an epoxy equivalent of 252 g/eq), 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 parts by mass of methylhydroquinone, and 200 parts by mass of propylene glycol monomethyl ether acetate were added. These were stirred under air bubbling to prepare a mixture. This mixture was heated in the flask under stirring under air bubbling at a heating temperature of 115° C. for a heating time of 12 hours. In this way, an intermediate solution was prepared.

Next, 58.8 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride and 7 parts by mass of propylene glycol monomethyl ether acetate were added to the intermediate solution in the flask. These were heated at a heating temperature of 115°C for 6 hours while being stirred under air bubbling. This resulted in a 65% by mass solution of photosensitive resin A1. The polydispersity (Mw/Mn) of photosensitive resin A1 was 2.11, the number average molecular weight (Mn) was 1486, and the acid value was 59 mgKOH.

(1-2) Synthesis example 2 (photosensitive resin A-2)
Into a four-neck flask equipped with a reflux condenser, a thermometer, an air inlet tube, and a stirrer, 252 parts by mass of a bisphenol fluorene type epoxy compound (an epoxy compound represented by formula (2) in which R ₁ to R ₈ in formula (2) are all hydrogen and have an epoxy equivalent of 252 g/eq), 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 parts by mass of 4-methoxyphenol, and 200 parts by mass of propylene glycol monomethyl ether acetate were added. These were stirred under air bubbling to prepare a mixture. This mixture was heated in the flask under stirring under air bubbling at a heating temperature of 115° C. for a heating time of 12 hours. In this way, an intermediate solution was prepared.

Next, 73.55 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride and 15 parts by mass of propylene glycol monomethyl ether acetate were added to the intermediate solution in the flask. These were heated at a heating temperature of 115°C for 6 hours while being stirred under air bubbling. This resulted in a 65% by mass solution of photosensitive resin A2. The polydispersity (Mw/Mn) of photosensitive resin A2 was 2.04, the number average molecular weight (Mn) was 1682, and the acid value was 69 mgKOH.

(1-3) Synthesis example 3 (photosensitive resin A-3)
Into a four-neck flask equipped with a reflux condenser, a thermometer, an air inlet tube, and a stirrer, 252 parts by mass of a bisphenol fluorene type epoxy compound (an epoxy compound represented by formula (2) in which R ₁ to R ₈ in formula (2) are all hydrogen and have an epoxy equivalent of 252 g/eq), 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 parts by mass of 4-methoxyphenol, and 200 parts by mass of propylene glycol monomethyl ether acetate were added. These were stirred under air bubbling to prepare a mixture. This mixture was heated in the flask under stirring under air bubbling at a heating temperature of 115° C. for a heating time of 12 hours. In this way, an intermediate solution was prepared.

Next, 15.4 parts by mass of 1,2,3,6-tetrahydrophthalic anhydride, 58.8 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 15 parts by mass of propylene glycol monomethyl ether acetate were added to the intermediate solution in the flask. These were heated at 115°C for 6 hours while stirring under air bubbling, and further heated at 60°C for 6 hours while stirring under air bubbling. This resulted in a 65% by mass solution of photosensitive resin A3. The polydispersity (Mw/Mn) of photosensitive resin A3 was 1.99, the number average molecular weight (Mn) was 1460, and the acid value was 71 mgKOH.

(1-4) Synthesis example 4 (photosensitive resin A-4)
Into a four-neck flask equipped with a reflux condenser, a thermometer, an air inlet tube, and a stirrer, 252 parts by mass of a bisphenol fluorene type epoxy compound (an epoxy compound represented by formula (2) in which R ₁ to R ₈ in formula (2) are all hydrogen and have an epoxy equivalent of 252 g/eq), 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 parts by mass of 4-methoxyphenol, and 200 parts by mass of propylene glycol monomethyl ether acetate were added. These were stirred under air bubbling to prepare a mixture. This mixture was heated in the flask under stirring under air bubbling at a heating temperature of 115° C. for a heating time of 12 hours. In this way, an intermediate solution was prepared.

Next, 60.8 parts by mass of 1,2,3,6-tetrahydrophthalic anhydride, 58.8 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 40 parts by mass of propylene glycol monomethyl ether acetate were added to the intermediate solution in the flask. These were heated at 115°C for 6 hours while stirring under air bubbling, and further heated at 60°C for 6 hours while stirring under air bubbling. This resulted in a 65% by mass solution of photosensitive resin A4. The polydispersity (Mw/Mn) of photosensitive resin A4 was 1.89, the number average molecular weight (Mn) was 1552, and the acid value was 104 mgKOH.

(1-5) Synthesis example 5 (photosensitive resin A-5)
Into a four-neck flask equipped with a reflux condenser, a thermometer, an air inlet tube, and a stirrer, 252 parts by mass of a bisphenol fluorene type epoxy compound (an epoxy compound represented by formula (2) in which R ₁ to R ₈ in formula (2) are all hydrogen and have an epoxy equivalent of 252 g/eq), 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 parts by mass of 4-methoxyphenol, and 200 parts by mass of propylene glycol monomethyl ether acetate were added. These were stirred under air bubbling to prepare a mixture. This mixture was heated in the flask under stirring under air bubbling at a heating temperature of 115° C. for a heating time of 12 hours. In this way, an intermediate solution was prepared.

Next, 115.5 parts by mass of 1,2,3,6-tetrahydrophthalic anhydride, 7.355 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 42 parts by mass of propylene glycol monomethyl ether acetate were added to the intermediate solution in the flask. These were heated at 115°C for 6 hours while stirring under air bubbling, and further heated at 60°C for 6 hours while stirring under air bubbling. This resulted in a 65% by mass solution of photosensitive resin A5. Photosensitive resin A5 had a polydispersity (Mw/Mn) of 1.28, a number average molecular weight (Mn) of 1054, and an acid value of 102 mgKOH.

(1-6) Synthesis example 6 (photosensitive resin A-6)
Into a four-neck flask equipped with a reflux condenser, a thermometer, an air inlet tube, and a stirrer, 252 parts by mass of a bisphenol fluorene type epoxy compound (an epoxy compound represented by formula (2) in which R ₁ to R ₈ in formula (2) are all hydrogen and have an epoxy equivalent of 252 g/eq), 64.8 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 parts by mass of 4-methoxyphenol, and 200 parts by mass of propylene glycol monomethyl ether acetate were added. These were stirred under air bubbling to prepare a mixture. This mixture was heated in the flask under stirring under air bubbling at a heating temperature of 115° C. for a heating time of 12 hours. In this way, an intermediate solution was prepared.

Next, 60.8 parts by mass of 1,2,3,6-tetrahydrophthalic anhydride, 58.8 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 36 parts by mass of propylene glycol monomethyl ether acetate were added to the intermediate solution in the flask. These were heated at 115°C for 6 hours while stirring under air bubbling, and further heated at 60°C for 6 hours while stirring under air bubbling. This resulted in a 65% by mass solution of photosensitive resin A6. The polydispersity (Mw/Mn) of photosensitive resin A6 was 2.21, the number average molecular weight (Mn) was 1753, and the acid value was 98 mgKOH.

(1-7) Synthesis example 7 (photosensitive resin B-1)
Into a four-neck flask equipped with a reflux condenser, a thermometer, an air inlet tube, and a stirrer, 252 parts by mass of a bisphenol fluorene type epoxy compound (an epoxy compound represented by formula (2) in which R ₁ to R ₈ in formula (2) are all hydrogen and have an epoxy equivalent of 252 g/eq), 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 parts by mass of 4-methoxyphenol, and 200 parts by mass of propylene glycol monomethyl ether acetate were added. These were stirred under air bubbling to prepare a mixture. This mixture was heated in the flask under stirring under air bubbling at a heating temperature of 115° C. for a heating time of 12 hours. In this way, an intermediate solution was prepared.

Next, 44.13 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added to the intermediate solution in the flask. The mixture was heated at 115°C for 6 hours while stirring under air bubbling, and further heated at 60°C for 6 hours while stirring under air bubbling. This resulted in a 65% by mass solution of photosensitive resin B1. The polydispersity (Mw/Mn) of photosensitive resin B1 was 1.56, the number average molecular weight (Mn) was 1364, and the acid value was 46 mgKOH.

(1-8) Synthesis example 8 (photosensitive resin B-2)
Into a four-neck flask equipped with a reflux condenser, a thermometer, an air inlet tube, and a stirrer, 650 parts by mass of a bisphenol fluorene type epoxy compound (an epoxy compound represented by formula (2) in which R ₁ to R ₈ in formula (2) are all hydrogen and have an epoxy equivalent of 650 g/eq), 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 parts by mass of 4-methoxyphenol, and 500 parts by mass of propylene glycol monomethyl ether acetate were added. These were stirred under air bubbling to prepare a mixture. This mixture was heated in the flask under stirring under air bubbling at a heating temperature of 115° C. for a heating time of 12 hours. In this way, an intermediate solution was prepared.

Next, 60.8 parts by mass of 1,2,3,6-tetrahydrophthalic anhydride, 58.8 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 4 parts by mass of propylene glycol monomethyl ether acetate were added to the intermediate solution in the flask. These were heated at 115°C for 6 hours while stirring under air bubbling, and further heated at 60°C for 6 hours while stirring under air bubbling. This resulted in a 65% by mass solution of photosensitive resin B2. The polydispersity (Mw/Mn) of photosensitive resin B2 was 4.12, the number average molecular weight (Mn) was 1324, and the acid value was 55 mgKOH.

(1-9) Synthesis example 9 (photosensitive resin C-1)
Into a four-neck flask equipped with a reflux condenser, a thermometer, an air inlet tube, and a stirrer, 252 parts by mass of a bisphenol fluorene type epoxy compound (an epoxy compound represented by the above formula (2) in which R ₁ to R ₈ in formula (2) are all hydrogen and have an epoxy equivalent of 252 g/eq), 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 parts by mass of 4-methoxyphenol, and 200 parts by mass of propylene glycol monomethyl ether acetate were added. These were stirred under air bubbling to prepare a mixture. This mixture was heated in the flask under stirring under air bubbling at a heating temperature of 115° C. for a heating time of 12 hours. In this way, an intermediate solution was prepared.

Next, 123.2 parts by mass of 1,2,3,6-tetrahydrophthalic anhydride and 42 parts by mass of propylene glycol monomethyl ether acetate were added to the intermediate solution in the flask. These were heated at 115°C for 6 hours while stirring under air bubbling, and further heated at 60°C for 6 hours while stirring under air bubbling. This resulted in a 65% by mass solution of photosensitive resin C1. Photosensitive resin C1 had a polydispersity (Mw/Mn) of 1.18, a number average molecular weight (Mn) of 783, and an acid value of 102 mgKOH.

(1-10) Synthesis example 10 (photosensitive resin C-2)
In a four-neck flask equipped with a reflux condenser, a thermometer, an air inlet tube, and a stirrer, 80 parts by mass of methacrylic acid, 95 parts by mass of methyl methacrylate, 25 parts by mass of styrene, 80 parts by mass of dipropylene glycol monomethyl ether acid, 430 parts by mass of dipropylene glycol monomethyl ether, and 3.5 parts by mass of azobisisobutyronitrile were added. The mixture in the four-neck flask was heated at a heating temperature of 75° C. for 5 hours while stirring under a nitrogen stream to allow the polymerization reaction to proceed. As a result, a copolymer solution with a concentration of 32% was obtained.

Next, 0.1 parts by mass of hydroquinone, 64 parts by mass of glycidyl methacrylate, and 0.8 parts by mass of dimethylbenzylamine were added to this copolymer solution. The mixture was heated with stirring at a heating temperature of 80°C for a heating time of 24 hours to allow the addition reaction to proceed. This resulted in a 38% by mass solution of photosensitive resin C2. The polydispersity (Mw/Mn) of photosensitive resin C2 was 2.13, the number average molecular weight (Mn) was 10,530, and the acid value was 104 mg KOH.

(2) Preparation of Photosensitive Composition [Examples and Comparative Examples]
The components shown in the table below were added to a flask and mixed with stirring at a temperature of 35° C. to obtain a photosensitive composition. Details of the components shown in the table are as follows.
Photopolymerization initiator A: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (manufactured by IGM Resins B.V., product number Omnirad TPO H).
Photopolymerization initiator B: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (manufactured by IGM Resins B.V., product number Omnirad 819).
Photopolymerization initiator C: 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (manufactured by IGM Resins B.V., product number Omnirad 907).
Photopolymerization initiator D: 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone (manufactured by IGM Resins B.V., product number Omnirad 369).
Photopolymerization initiator E: ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime) (manufactured by BASF Japan Ltd., product number Irgacure OXE02).
Photopolymerization initiator F: 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by IGM Resins B.V., product number Omnirad 184).
Photopolymerizable compound A: trimethylolpropane triacrylate.
Photopolymerizable compound B: tricyclodecane dimethanol diacrylate.
Photopolymerizable compound C: dipentaerythritol penta- and hexaacrylate (manufactured by Nippon Kayaku Co., Ltd., product number KAYARAD DPHA).
Antioxidant: Pentaerythritol tetrakis (3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) (manufactured by BASF Japan Ltd., product number Irganox 1010).
Surface modifier: surfactant (manufactured by DIC Corporation, product number Megafac F-557)
Epoxy compound A: biphenyl-type crystalline epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name YX-4000, melting point 105° C., epoxy equivalent 187 g/eq.).
Epoxy compound B: bisphenol A type epoxy resin, manufactured by Nippon Steel Chemical & Material Co., Ltd., product number YD-128, epoxy equivalent 187 g/eq.
Solvent A: propylene glycol monomethyl ether.
Solvent B: methyl ethyl ketone.
Solvent C: propylene glycol monomethyl ether acetate.

(3) Preparation of Test Pieces Test pieces were prepared from the photosensitive compositions prepared in (2) above as follows.

First, a glass epoxy copper-clad laminate (FR-4 type) with a copper foil of 17.5 μm thickness was prepared. The surface portion of the copper foil of this printed wiring board, which was about 1 μm thick, was dissolved and removed with an etching agent (product number CZ-8101, manufactured by MEC Co., Ltd.), to roughen the copper foil. The compositions of each example and comparative example were applied to this substrate with an applicator to form a wet coating film. This coating film was thermally dried at 120°C for 5 minutes, forming a film of 10 μm thickness on the copper foil.

A negative mask having a pattern including lines with line widths of 6 μm, 8 μm, and 10 μm and having non-exposed areas was directly applied to this film, and the film was irradiated with ultraviolet rays from an ultra-high pressure mercury lamp at 400 mJ/ ^cm2 . The exposed film was subjected to a development process.

In the development process, a 1% _Na2CO3 aqueous solution _at 30°C was sprayed onto the film at a spray pressure of 0.05 MPa for 60 seconds. If the film could not be developed after 60 seconds of spraying, it was sprayed for 90 seconds. If the film could not be developed after 90 seconds of spraying, it was sprayed for 120 seconds. Next, pure water was sprayed onto the film at a spray pressure of 0.05 MPa for 60 seconds. This removed the unexposed parts of the film, forming a line-free pattern on the film.

Next, examples 14 and 15 were thermally cured at 150°C for 30 minutes.

Next, for each of the Examples and Comparative Examples, the coating was irradiated with ultraviolet light from a metal halide lamp at 1000 mJ/ ^cm2 to produce a cured product of the photosensitive composition. Thus, test pieces were obtained.

(4) Evaluation (4-1) Transmittance The photosensitive composition prepared in (2) above was applied to a polyethylene terephthalate (PET) film with an applicator to form a wet coating film. This coating film was dried by heating at 120°C for 5 minutes to form a 10 μm thick film (dried film) on the PET film. Next, the entire surface of the film formed on the PET film was irradiated with ultraviolet light at 400 mJ/ ^cm2 from an ultra-high pressure mercury lamp. The exposed film was subjected to a development treatment. In the development treatment, a 1% Na ₂ CO ₃ aqueous solution at 30°C was sprayed onto the film at a spray pressure of 0.05 MPa for 60 seconds. Next, pure water was sprayed onto the film at a spray pressure of 0.05 MPa for 60 seconds.

The coating was then irradiated with ultraviolet light from a metal halide lamp at 1000 mJ/ ^cm2 to cure the photosensitive composition. The cured product prepared on the PET film was set in a UV-Vis-Near-Infrared Spectrophotometer (Shimadzu Corporation, product number UV-3100PC) to measure the transmittance of the cured product from 450 to 800 nm. The PET film, which was the substrate, was used as a reference. The obtained transmittance curves were evaluated according to the following criteria, and the results are shown in Tables 1 to 3.
◯: In the wavelength range of 450 nm to 800 nm, the transmittance was 90% or more in all cases.
Δ: In the wavelength range of 450 nm to 800 nm, there was a wavelength range in which the transmittance was 85% or more and less than 90%.
×: In the wavelength range of 450 nm to 800 nm, there was a wavelength range in which the transmittance was less than 85%.

In addition, the transmittance of each of the measurement samples of the cured product prepared by the above method, after storage at -40°C for 1000 hours and after storage at 105°C for 1000 hours, was measured in the same manner as above to obtain a transmittance curve, and the transmittance curve was evaluated according to the same criteria as above.

(4-2) Absorption spectrum The photosensitive composition prepared in (2) above was applied to a PET film with an applicator to prepare a wet coating film. This coating film was dried by heating at 120° C. for 5 minutes to prepare a film (dried film) having a thickness of 10 μm on the PET film. The film prepared on the PET film was set in an ultraviolet-visible-near infrared spectrophotometer (Shimadzu Corporation, product number UV-3100PC) to measure the absorption spectrum of the film from 250 to 800 nm. The PET film, which is the substrate, was used as a reference. The obtained absorption spectrum was evaluated according to the following criteria, and the results are shown in Tables 1 to 3. In Tables 1 to 3, the maximum absorbance is shown in parentheses in the column of [Maximum absorbance at 300 nm to 330 nm].

[Wavelength range including maximum absorbance]
◯: In the wavelength range of 250 nm to 800 nm, the maximum absorbance is in the wavelength range of 300 nm to 330 nm.
×: In the wavelength range of 250 nm to 800 nm, the maximum absorbance value is not in the wavelength range of 300 nm to 330 nm.

[Maximum absorbance at 300 nm to 330 nm]
◯: The maximum absorbance value is 1 or more in the wavelength range of 300 nm to 330 nm.
×: The maximum absorbance value is less than 1 in the wavelength range of 300 nm to 330 nm.

(4-3) Low Tackiness In the same manner as in (4-1) above, a film (dried film) was prepared on a PET film, and the stickiness was evaluated by pressing a finger against the dried film.

Furthermore, similar to (4-1) above, a cured photosensitive resin was produced by exposing the coating on the PET film to light and curing it. When curing the photosensitive resin, the negative mask was peeled off after exposure, and the cured photosensitive resin was observed.

From the above results, the low tackiness was evaluated according to the following criteria, and the results are shown in Tables 1 to 3.
A: When the film after thermal drying is pressed with a finger, it does not feel sticky, and no traces of the negative mask are visible on the cured product after exposure.
B: When the film after thermal drying is pressed with a finger, it feels sticky, but no traces of the negative mask are visible on the cured product after exposure.
C: When the film after heat drying is pressed with a finger, it feels sticky, and traces of the negative mask are visible on the cured product after exposure.
D: When the film after heat drying was pressed with a finger, it felt very sticky, and further, when the negative mask was peeled off after exposure, transfer of the cured material to the negative mask was observed.

(4-4) Developability In the preparation of the test pieces in (3) above, the test pieces after development were observed and evaluated according to the following criteria. The results are shown in Tables 1 to 3.
A: No development residue was observed after development in _a 1% _Na2CO3 aqueous solution at 30°C and 0.05 MPa for 60 seconds.
B: Development residue is observed after development in _a 1% _Na2CO3 aqueous solution at 30°C, 0.05 MPa for 60 seconds, but no development residue is observed after development in _a 1% _Na2CO3 aqueous solution at 30°C, 0.05 MPa for 90 seconds.
C: Development residues were observed after development in _a 1% _Na2CO3 aqueous solution at 30°C and 0.05 MPa for 90 seconds, but no development residues were observed after development in _a 1% _Na2CO3 aqueous solution at 30°C and 0.05 MPa for 120 seconds.
D: Development residue was observed after development with 1% _Na2CO3 aqueous solution at 30°C and 0.05 MPa for 120 _seconds .

(4-5) Resolution The test pieces prepared in (3) above were observed and evaluated according to the following criteria. The results are shown in Tables 1 to 3.
A: A space with a line width of 6 μm is resolved.
B: A space with a line width of 6 μm cannot be resolved, but a space with a line width of 8 μm can be resolved.
C: A space with a line width of 8 μm cannot be resolved, but a space with a line width of 10 μm can be resolved.
D: A space with a line width of 10 μm cannot be resolved.

(4-6) Electroless plating resistance (plating resistance)
A nickel plating layer was formed on the exposed portion of the copper foil of the test piece prepared in (3) above using a commercially available electroless nickel plating bath, and then a gold plating layer was formed using a commercially available electroless gold plating bath, and the appearance of the layer made of the cured product and the metal layer was visually observed. In addition, a cellophane adhesive tape peeling test was performed on the layer made of the cured product of the photosensitive resin. The results of the above test were evaluated according to the following criteria, and the results are shown in Tables 1 to 3. A: No abnormality was observed in the appearance of the layer made of the cured product and the metal layer, and the layer made of the cured product did not peel off during the cellophane adhesive tape peeling test.
B: Slight discoloration was observed in the layer made of the cured product, but the layer made of the cured product did not peel off in a cellophane adhesive tape peeling test.
C: Discoloration was observed in the layer made of the cured product, but the layer made of the cured product did not peel off in a cellophane adhesive tape peeling test.
D: Lifting of the layer made of the cured product was observed, and peeling of the layer made of the cured product occurred when a cellophane adhesive tape peel test was performed.

(4-7) Electrical Insulation Property Using a B pattern of a printed circuit board (thickness 1.6 mm) specified by IPC, the photosensitive composition was applied and cured by the method described above, and the electrical insulation property of the obtained cured film was evaluated according to the following criteria.
Measurement conditions: measurement time 60 seconds, applied voltage 500V.
A: Insulation resistance value is 10 ¹¹ Ω or more.
B: Insulation resistance value is 10 ¹⁰ Ω or more and less than 10 ¹¹ Ω.
C: Insulation resistance value is 10 ⁹ Ω or more and less than 10 ¹⁰ Ω.
D: Insulation resistance value is less than 10 ⁹ Ω.

(4-8) Coating property on each substrate and resistance of substrate The photosensitive composition prepared in (2) above was applied onto a substrate (PET substrate, COP substrate, or PC substrate), followed by heating and drying, exposure, and development to produce a cured product of the photosensitive resin on the substrate, and the resistance of the substrate to the photosensitive resin was evaluated. The specific test method is as follows.

(4-8-1) PET substrate The photosensitive composition prepared in (2) was applied to a PET film, and the composition was heated and dried, exposed to light, and developed in the same manner as described in the preparation of the test pieces in (3) above, to prepare samples for evaluation. Note that, for Examples 14 and 15, the "thermal curing at 150°C for 30 minutes" described in (3) above was not performed. The obtained evaluation samples were visually observed and evaluated according to the following criteria.
◯: A uniform cured film is obtained. In addition, abnormalities such as whitening, cracks, and breakage do not occur on the substrate.
×: A uniform cured film was not obtained, or the substrate had defects such as whitening, cracks, and breakage.

(4-8-2) COP substrate A cured photosensitive resin was prepared on the substrate in the same manner as in (4-8-1) above, except that the substrate in (4-8-1) above was changed to a film made of cycloolefin polymer (COP: Cyclo Olefin polymer), and a sample for evaluation was obtained. The obtained evaluation sample was visually observed and evaluated according to the following criteria.
◯: A uniform cured film is obtained. In addition, abnormalities such as whitening, cracks, and breakage do not occur on the substrate.
×: A uniform cured film was not obtained, or abnormalities such as whitening, cracks, and breakage occurred in the substrate.

(4-8-3) PC substrate A cured photosensitive resin was prepared on the substrate in the same manner as in (4-8-1) above, except that the substrate in (4-8-1) above was changed to a polycarbonate (PC) film, and a sample for evaluation was obtained. The obtained evaluation sample was visually observed and evaluated according to the following criteria.
◯: A uniform cured film is obtained. In addition, abnormalities such as whitening, cracks, and breakage do not occur on the substrate.
×: A uniform cured film was not obtained, or abnormalities such as whitening, cracks, and breakage occurred in the substrate.

1 Base material 40 Transparent cured film 10 Laminated body

Claims (13)

A photosensitive resin (A) containing a resin having an ethylenically unsaturated group and a carboxyl group;
A photopolymerization initiator (B);
A photosensitive composition comprising a photopolymerizable compound (C),
The photosensitive resin (A) contains a photosensitive resin (A1) produced by reacting a product produced by reacting an epoxy compound (a1) having at least two epoxy groups with a carboxylic acid (a2) having an ethylenically unsaturated group, and an acid anhydride (a3) containing an acid dianhydride (a4),
the photosensitive resin (A1) has a number average molecular weight Mn of 500 or more and 2000 or less, a polydispersity Mw/Mn of 1.2 or more and 2.8 or less, and an acid value of 55 mgKOH/g or more and 130 mgKOH/g or less;
The epoxy compound (a1) contains a compound having a bisphenol fluorene skeleton,
the photosensitive composition does not contain an epoxy compound (D), or contains the epoxy compound (D) such that the total equivalent of the epoxy groups contained in the epoxy compound (D) is more than 0 equivalent and 0.6 equivalents or less relative to 1 equivalent of the carboxyl groups contained in the photosensitive resin (A);
When a dry film having a thickness of 10 μm is produced from the photosensitive composition, the light transmittance at a wavelength of 450 to 800 nm is 85% or more, the maximum absorbance of the dry film in the wavelength range of 250 to 800 nm is in the wavelength range of 300 to 330 nm, and the maximum absorbance is 1 or more.
Photosensitive composition. The photosensitive resin (A) contains a resin having an epoxy group.
The photosensitive composition of claim 1. The acid anhydride (a3) further contains an acid monoanhydride (a5).
The photosensitive composition according to claim 1 or 2. The acid dianhydride (a4) contains 3,3',4,4'-biphenyltetracarboxylic dianhydride.
The photosensitive composition according to any one of claims 1 to 3. the amount of the acid dianhydride (a4) is 0.01 mol or more and 0.24 mol or less relative to 1 mol of the epoxy compound (a1);
The photosensitive composition according to any one of claims 1 to 4. The photopolymerization initiator (B) contains at least one selected from the group consisting of an α-aminoalkylphenone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and an oxime ester-based photopolymerization initiator.
The photosensitive composition according to any one of claims 1 to 5. The photopolymerizable compound (C) contains at least one of a difunctional unsaturated compound and a trifunctional unsaturated compound.
The photosensitive composition according to any one of claims 1 to 6. Further containing a solvent (E),
The ratio of the solvent (E) is 50% by mass or more based on the photosensitive composition.
The photosensitive composition according to any one of claims 1 to 7. The solvent (E) contains an alcohol-based solvent (E1).
The photosensitive composition according to claim 8. The solvent (E) contains propylene glycol monomethyl ether.
The photosensitive composition according to claim 8 or 9. A cured product of the photosensitive composition according to any one of claims 1 to 10.
Transparent cured film. A substrate and the transparent cured film according to claim 11 overlapping the substrate.
Laminate. A photosensitive composition according to any one of claims 1 to 10 is applied onto a substrate to form a dry film having a thickness of 10 µm or less;
The dried film is partially exposed to light and then developed with an alkaline developer to form a pattern, thereby producing a transparent cured film overlying the substrate.
A method for manufacturing a laminate.

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