Cured products, photosensitive resin compositions, dry films, and printed circuit boards

Abstract

The present invention provides a cured product that allows for easy application of marking ink to the surface, exhibits excellent adhesion to the marking ink after curing, and enables the formation of markers with excellent visibility of letters and symbols on the surface. [Solution] A cured product comprising a curable resin composition containing a curable resin and an inorganic filler, wherein the inorganic filler contains amorphous silica, and the average coefficient of linear expansion of a cured product with a thickness of 20 μm is 70 to 100 ppm / °C when the temperature is changed from 0°C to 180°C.

Description

Cross-reference of related applications

[0001] This application claims priority based on Japanese Patent Application No. 2022-060840 and Japanese Patent Application No. 2022-060828, both filed in Japan on March 31, 2022, and the contents thereof are incorporated herein by reference. [Technical Field]

[0002] The present invention relates to cured products and photosensitive resin compositions, and more particularly to cured products of curable resin compositions, photosensitive resin compositions and dry films, and printed circuit boards equipped with a coating made of the cured product. [Background technology]

[0003] Generally, in printed circuit boards used in electronic devices and the like, a solder resist layer is formed in the area of ​​the substrate excluding the connection holes where the circuit pattern is formed, in order to prevent solder from adhering to unwanted parts of the printed circuit board during processes such as solder reflow when mounting electronic components to the printed circuit board. The solder resist layer is formed by applying a liquid curable resin composition to the substrate and then curing it, or by using a curable dry film without using a liquid curable resin composition. As a composition suitable for forming a solder resist layer, for example, Patent Document 1 discloses a curable resin composition containing a carboxyl group-containing resin having a specific acid value, an acrylic copolymer, an epoxy resin, etc. Patent Document 2 also discloses a photosensitive film laminate having a layer containing inorganic particles as a dry film for forming a solder resist layer.

[0004] Incidentally, on the surface of printed circuit boards, identification characters or symbols (markers) are sometimes printed using marking ink to indicate the mounting positions of electronic components, taking into consideration the subsequent mounting process of electronic components. Marking inks mainly include thermosetting and UV-curing types formed by pattern printing, or alkaline-developable types formed by exposure through a negative film and removal of unexposed areas with an alkaline aqueous solution. More recently, a technique called laser marking has also been used, which changes the color tone of the irradiated area by irradiating it with laser light to display characters or symbols.

[0005] As described above, when markers are formed on a printed circuit board equipped with a solder resist layer using marking ink, depending on the application and curing conditions of the marking ink, the marking ink may be difficult to print or may peel off easily, resulting in reduced visibility of the marker. This tendency was particularly pronounced when the curing conditions of the marking ink were strict (for example, when the marking ink consists of a photocurable and thermocurable resin composition, and both photocuring and thermocuring are required to cure the ink).

[0006] On the other hand, solder resist layers have various requirements such as solder heat resistance, crack resistance, and insulation reliability, and photosensitive resin compositions that satisfy these required characteristics are being investigated. For example, Patent Document 3 proposes a photosensitive resin composition that can suppress the occurrence of cracks without reducing heat resistance, by using a combination of a bisphenol-type carboxyl group-containing resin and a novolac-type carboxyl group-containing resin.

[0007] Furthermore, in the manufacturing process of printed circuit boards, after forming a solder resist layer, gold plating or tin plating is usually applied for surface treatment of conductor patterns, formation of terminals for printed contacts, and formation of bonding pads. Since these plating processes do not require current or plating leads, electroless gold plating and electroless tin plating are now commonly used, and therefore, there is a need for improved resistance to plating solutions in photosensitive resin compositions. For example, Patent Document 4 proposes using a combination of a bisphenol-type carboxyl group-containing resin and a carboxyl group-containing resin which is a reaction product of an unsaturated basic acid copolymer resin and an alicyclic epoxy group-containing unsaturated compound, as a photosensitive resin composition with excellent chemical resistance to plating solutions.

[0008] When using a photosensitive resin composition such as that described in Patent Document 3, the plating solution tends to become contaminated during electroless plating, which can sometimes lead to plating defects or an increased frequency of plating solution replacement. Furthermore, when using a photosensitive resin composition such as that described in Patent Document 4, development residue can re-adhere to the substrate during the development process after exposure, and in some cases, the adhering development residue can cause plating defects. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 10-142793 [Patent Document 2] Japanese Patent Publication No. 2018-169537 [Patent Document 3] Japanese Patent Publication No. 2017-529551 [Patent Document 4] Brochure for International Patent Application Publication WO2003 / 032089 [Overview of the Initiative]

[0010] Therefore, the present invention has been made in view of the above problems, and its object is to provide a cured product that allows marking ink to be easily applied to the surface, has excellent adhesion to the marking ink after curing, and can form a marker on the surface with excellent visibility of characters and symbols. Another object of the present invention is to provide a photosensitive resin composition that can suppress contamination of the plating solution and suppress plating defects while satisfying the properties required of solder resist, such as insulation reliability.

[0011] In response to the above problems, the inventors conducted various studies and found that the printability and adhesion of marking ink to the surface of the cured product are influenced by the state of the curable resin composition during the formation of the cured coating. Specifically, they found that if warping or cracks occur on the surface during the formation of the cured coating, the marking ink may not print properly afterward, or even if it does print, it may peel off in the post-curing process. Furthermore, the inventors found that in order to prevent warping and cracking, the above problems can be solved if the curable resin composition contains a specific silica and the average coefficient of linear expansion of the cured product formed by that curable resin composition is within a specific range. Furthermore, we have found that by using three specific carboxyl group-containing resins in combination as photosensitive resin components, it is possible to obtain a photosensitive resin composition that can suppress contamination of the plating solution and also suppress plating defects while satisfying the properties required for solder resist, such as insulation reliability. The present invention is based on this finding. In other words, the gist of this invention is as follows:

[0012] [1] A cured product comprising a curable resin composition containing a curable resin and an inorganic filler, The inorganic filler contains amorphous silica, A cured product characterized in that its average coefficient of linear expansion when the temperature is changed from 0°C to 180°C is 70 to 100 ppm / °C. [2] The cured product according to [1], wherein the glass transition temperature (Tg) is in the range of 100 to 120°C. [3] The cured product according to [1], wherein the average coefficient of linear expansion of the cured product when the temperature is changed from 0°C to 180°C is 70 to 85 ppm / °C. [4] The cured product according to [1], wherein the curable resin comprises a thermosetting resin and a photocurable resin. [5] The cured product according to [1], wherein the amorphous silica is contained in an amount of 2 to 30% by mass relative to the entire curable resin composition on a solid content basis. [6] A photosensitive resin composition comprising (A) a carboxyl group-containing resin, (B) a photopolymerizable monomer, and (C) a thermosetting component, (A) A carboxyl group-containing resin, (A1) A carboxyl group-containing resin having a novolac skeleton, (A2) A carboxyl group-containing resin having a bisphenol skeleton, (A3) An unsaturated basic acid copolymer type carboxyl group-containing resin, Includes, The total amount of the carboxyl group-containing resin (A1) and the carboxyl group-containing resin (A2) is 60 to 80% by mass relative to the total amount of the carboxyl group-containing resin (A). A photosensitive resin composition characterized in that the amount of the carboxyl group-containing resin (A3) is 40 to 20% by mass relative to the total amount of the carboxyl group-containing resin (A). [7] The photosensitive resin composition according to [6], wherein the carboxyl group-containing resin of (A3) is a reaction product of an unsaturated basic acid copolymer resin and an alicyclic epoxy group-containing unsaturated compound. [8] The photosensitive resin composition according to [6], wherein the amount of the carboxyl group-containing resin (A1) is 10 to 60% by mass relative to the total amount of the carboxyl group-containing resin (A). [9] The photosensitive resin composition according to [6], wherein the amount of the carboxyl group-containing resin (A2) is 20 to 50% by mass relative to the total amount of the carboxyl group-containing resin (A).

[10] The photosensitive resin composition according to [6], wherein the (C) thermosetting component comprises an epoxy resin having an isocyanuric ring.

[11] The photosensitive resin composition according to [6], further comprising an inorganic filler.

[12] The photosensitive resin composition according to

[11] , wherein the inorganic filler (D) contains fused silica.

[13] A dry film having a resin layer obtained by applying the photosensitive resin composition according to [6] to a first film and drying.

[14] A cured product obtained by curing the resin layer of the photosensitive resin composition according to [6] or the dry film according to

[13] .

[15] The cured product according to [1] or

[14] , which is used for a solder resist.

[16] A printed wiring board provided with the cured product according to [1] or

[14] on a substrate.

[0013] According to the cured product of the present invention, it is easy to apply marking ink on the surface, has excellent adhesion to the marking ink after curing, and further, it is possible to form a marker with excellent visibility of characters and symbols on the surface. According to the photosensitive resin composition of the present invention, as the photosensitive resin component, by using three specific carboxyl group-containing resins in a specific ratio in combination, while satisfying the properties required for a solder resist such as insulation reliability, it is possible to suppress contamination of the plating solution and also suppress plating defects.

Embodiments for Carrying Out the Invention

[0014] [Definition] In the present invention, the "average linear expansion coefficient" refers to the ratio at which the length of the cured product as a test piece expands per 1 °C due to an increase in temperature. Further, the cured product in the present invention is obtained by curing a curable resin composition, a photosensitive resin composition, and a resin layer in a dry film (hereinafter sometimes referred to as a curable resin composition, etc.), and a cloth containing isopropyl alcohol is placed on the surface of the curable resin composition, etc. after the curing treatment, and further, a 500 g weight is placed thereon and left standing for 1 minute, and then it means that the curable resin composition, etc. is not adhered to the surface of the cloth.

[0015] [Cured product] The cured product according to the present invention is obtained by curing a curable resin composition containing a curable resin and an inorganic filler, and is characterized in that the average linear expansion coefficient in the length direction (perpendicular to the thickness direction) of the cured product in the form of a 20 μm thick film is 70 to 100 ppm / °C when the temperature is changed from 0°C to 180°C. According to the present invention, if the average linear expansion coefficient of the cured product is within the above range, it is possible to form a marker that is easy to apply marking ink to the surface, has excellent adhesion to the marking ink after curing, and also has excellent visibility of letters and symbols on the surface. The reason for this is not clear, but it can be inferred as follows: That is, if the cured product has an average linear expansion coefficient of 70 to 100 ppm / °C when the temperature is raised from 0°C to 180°C, warping and cracks on the surface are less likely to occur when curing the curable resin composition to form the cured product, and as a result, it is possible to form a marker that is easy to apply marking ink to the surface of the cured product and has high visibility. Furthermore, since the curable resin composition contains amorphous silica as an inorganic filler, and this amorphous silica has lower surface smoothness compared to other silicas, its anchoring effect improves the adhesion between the cured product and the marking ink, thus suppressing the peeling of the marker from the surface of the cured product. A more preferable average coefficient of linear expansion is 70-85 ppm / °C.

[0016] The average linear expansion coefficient of a cured product can be measured by a standard method using a thermomechanical analyzer, but in this invention, it refers to the value measured as described below. First, a curable resin composition is applied to copper foil, dried, and then cured by heating or light irradiation to obtain a flat film-like cured product with a thickness of 20 μm after curing. Next, the hardened material is cut into 3mm wide and 30mm long specimens to form test pieces, and the coefficient of thermal expansion in tensile mode is measured using a thermomechanical analyzer (TMA / SS6000, manufactured by Seiko Instruments Inc.). The maximum tensile load is 50 N / m, the span (distance between chucks) is 10 mm, and the heating rate is 10 °C / min. The test pieces are mounted in the thermomechanical analyzer and heated from 30 °C to 200 °C, then left for 10 minutes. After that, they are cooled to -30 °C at a cooling rate of -10 °C / min, and measurements are taken from -30 °C to 250 °C at a heating rate of 10 °C / min. The measured values ​​at 0 °C and 180 °C are read, and the average linear expansion coefficient (α) is calculated using the following formula. α=(1 / LS)×[{L(180)-L(0)} / (T(180)-T(0)] (Note that in the formula, LS: Length of the test specimen (cured material) before measurement (measured value) L(0): Change in length of the test specimen (cured material) at 0°C (measured value) L(180): Change in length of the test specimen (cured material) at 180°C (measured value) T(0):0(℃) T(180): 180(℃) (That is the case.)

[0017] Furthermore, it is preferable that the cured product of the present invention has a glass transition temperature (Tg) in the range of 100 to 120°C. By making the cured product such that the Tg is in this range, the coefficient of linear expansion is also more likely to fall within the desired range, resulting in a stable cured product and improved marking adhesion. The Tg of the cured product of the present invention can be determined using the TMA curve obtained by measuring with a thermomechanical analyzer (TMA) as follows: Specifically, from the TMA curve measured under the same conditions as the average coefficient of linear expansion, a straight line A passing through the two points 0°C and 30°C and a straight line B passing through the two points 150°C and 180°C are drawn, and the temperature at the point where straight line A and straight line B intersect (extrapolation point) is taken as the Tg of the cured product of the present invention.

[0018] The average coefficient of linear expansion (α) of the cured product of the present invention can be appropriately adjusted not only by the glass transition point described above, but also by the blending ratio of the curable resin and inorganic filler, and the degree of curing by heating or light irradiation. Furthermore, the glass transition point of the cured product of the present invention can be appropriately adjusted by the combination (compatibility) of the curable resin and other resins contained in the curable resin composition.

[0019] [Curable resin composition] The cured product according to the present invention is obtained by curing a curable resin composition. The curable resin composition includes a curable resin and an inorganic filler. Needless to say, in addition to the curable resin and inorganic filler, optional additives such as curing agents, curing accelerators, and colorants may be included as needed to cure the curable components. The components constituting the curable resin composition will be described below.

[0020] <Curable resin> Examples of curable resins include acrylic resins, epoxy resins, epoxy acrylate resins, silicone resins, phenolic resins, polyimide resins, polyurethane resins, melamine resins, urea resins, and other photocurable or thermosetting resins having photocurable or thermosetting functional groups. These resins may be used individually or in combination of two or more, but using both photocurable and thermosetting resins in combination is preferable because it allows for excellent adhesion even under harsh curing conditions such as dual curing.

[0021] Examples of photocurable resins include polymerizable monomers and oligomers. As polymerizable monomers, photopolymerizable monomers having an ethylenically unsaturated double bond are preferably used. Examples of photopolymerizable monomers include well-known and conventional polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, and epoxy (meth)acrylates. Specifically, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; acrylamides such as N,N-dimethylacrylamide, N-methylolacrylamide, and N,N-dimethylaminopropylacrylamide; aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate; polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tris-hydroxyethyl isocyanurate, or their ethyloxide adducts, propylene oxide adducts, or ε-caprolactone adducts. Polyvalent acrylates such as additives; polyvalent acrylates such as phenoxyacrylate, bisphenol A diacrylate, and ethylene oxide adducts or propylene oxide adducts of these phenols; polyvalent acrylates of glycidyl ethers such as glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate; and, not limited to the above, acrylates obtained by directly acrylateting polyols such as polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadienes, and polyester polyols, or by urethane acrylates obtained via diisocyanate, as well as melamine acrylate and at least one of the methacrylates corresponding to the acrylates can be appropriately selected and used. Such photopolymerizable monomers can also be used as reactive diluents.

[0022] Furthermore, polymerizable oligomers include unsaturated polyester oligomers and (meth)acrylate oligomers. Examples of (meth)acrylate oligomers include epoxy (meth)acrylates such as phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol-type epoxy (meth)acrylate, as well as urethane (meth)acrylate, epoxy urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and polybutadiene-modified (meth)acrylate.

[0023] The amount of photocurable resin in a curable resin composition is preferably 1 to 40 parts by mass, and more preferably 5 to 35 parts by mass, per 100 parts by mass of the carboxyl group-containing resin, when the curable resin composition contains a carboxyl group-containing resin as described later, on a solid content basis.

[0024] Furthermore, the curable resin composition may include a photosensitive resin that can be patterned by exposure and development. Such a photosensitive resin is preferable because it can be patterned by exposure and development to form a resin-cured film with a desired pattern on a substrate.

[0025] Any known thermosetting resin can be used as the curable resin. For example, amino resins such as melamine resin, benzoguanamine resin, melamine derivatives, and benzoguanamine derivatives, isocyanate compounds, blocked isocyanate compounds, cyclocarbonate compounds, epoxy compounds, oxetane compounds, episulfide resins, bismaleimide, and carbodiimide resins can be used. Particularly preferred are compounds having multiple cyclic ether groups or cyclic thioether groups (hereinafter abbreviated as cyclic (thio) ether groups) in the molecule. These thermosetting resins can be used individually or in combination of two or more. By including a thermosetting resin, the strength of the cured film in subsequent processes can be improved.

[0026] The compounds having multiple cyclic (thio) ether groups in their molecules are compounds having multiple 3, 4, or 5-membered cyclic (thio) ether groups in their molecules. Examples include compounds having multiple epoxy groups in their molecules, i.e., polyfunctional epoxy compounds; compounds having multiple oxetanyl groups in their molecules, i.e., polyfunctional oxetane compounds; and compounds having multiple thio ether groups in their molecules, i.e., episulfide resins.

[0027] Examples of such polyfunctional epoxy compounds include bisphenol A type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, brominated bisphenol A type epoxy resins, bisphenol S type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, biphenyl type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins, and triphenylmethane type epoxy resins.

[0028] Examples of commercially available polyfunctional epoxy compounds include jER 828, 806, 807, YX8000, YX8034, 834 from Mitsubishi Chemical Corporation, YD-128, YDF-170, ZX-1059, ST-3000 from Nippon Steel Chemical & Material Corporation, EPICLON 830, 835, 840, 850, N-730A, N-695 from DIC Corporation, and RE-306 from Nippon Kayaku Co., Ltd.

[0029] Examples of polyfunctional oxetane compounds include bis[(3-methyl-3-oxetanylmethoxy)methyl] ether, bis[(3-ethyl-3-oxetanylmethoxy)methyl] ether, 1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, (3-methyl-3-oxetanyl)methyl acrylate, and (3-ethyl-3-oxetanyl)methyl acrylate. Examples include polyfunctional oxetanes such as relates, (3-methyl-3-oxetanyl)methyl methacrylate, (3-ethyl-3-oxetanyl)methyl methacrylate, and their oligomers or copolymers, as well as ethers of oxetane alcohols with resins having hydroxyl groups such as novolac resins, poly(p-hydroxystyrene), cardo-type bisphenols, calixarenes, calixresorcinarenes, or silsesquioxane. Other examples include copolymers of unsaturated monomers having an oxetane ring with alkyl (meth)acrylates.

[0030] Examples of compounds having multiple cyclic thioether groups in their molecules include bisphenol A-type episulfide resins. Furthermore, episulfide resins obtained by replacing the oxygen atoms in the epoxy groups of novolac-type epoxy resins with sulfur atoms using a similar synthesis method can also be used.

[0031] The amount of compound having multiple cyclic (thio) ether groups in its molecule is preferably 0.8 to 2.5 mol, more preferably 1.0 to 2.0 mol, of functional groups of the compound having multiple cyclic (thio) ether groups in its molecule per 1.0 mol of carboxyl group in the resin, when a carboxyl group-containing resin is included. By setting the amount to 0.8 mol or more, the residual carboxyl groups in the cured film can be prevented, thereby obtaining good heat resistance, alkali resistance, electrical insulation, etc. Furthermore, by setting the amount to 2.5 mol or less, the residual low molecular weight cyclic (thio) ether groups in the dried coating can be prevented, thereby ensuring good strength of the cured film, etc.

[0032] Furthermore, if the compound having multiple cyclic (thio) ether groups in its molecule is a polyfunctional epoxy compound and contains a carboxyl group-containing resin, the amount of the polyfunctional epoxy compound blended is preferably 20 to 50 parts by mass per 100 parts by mass of the carboxyl group-containing resin, based on solid content.

[0033] Examples of amino resins such as melamine derivatives and benzoguanamine derivatives include methylolmelamine compounds, methylolbenzoguanamine compounds, methylol glycol uryl compounds, and methylol urea compounds.

[0034] Polyisocyanate compounds can be incorporated as isocyanate compounds. Examples of polyisocyanate compounds include aromatic polyisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, and 2,4-tolylene dimer; aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-methylenebis(cyclohexyl isocyanate), and isophorone diisocyanate; alicyclic polyisocyanates such as bicycloheptane triisocyanate; and adducts, biuret compounds, and isocyanurates of the isocyanate compounds mentioned above.

[0035] As the blocking isocyanate compound, the addition reaction product of an isocyanate compound and an isocyanate blocking agent can be used. Examples of isocyanate compounds that can react with an isocyanate blocking agent include the polyisocyanate compounds mentioned above. Examples of isocyanate blocking agents include phenol-based blocking agents, lactam-based blocking agents, active methylene-based blocking agents, alcohol-based blocking agents, oxime-based blocking agents, mercaptan-based blocking agents, acid amide-based blocking agents, imide-based blocking agents, amine-based blocking agents, imidazole-based blocking agents, and imine-based blocking agents.

[0036] In the present invention, the curable resin is preferably an alkali-soluble resin in that it can be developed when patterning. When the curable resin composition contains an alkali-soluble resin, it is preferable that other components include a photopolymerizable monomer and a photopolymerization initiator.

[0037] The alkali-soluble resin can be any resin that dissolves in an alkaline aqueous solution, and known and commonly used resins are used. Alkali-soluble resins can be used individually or in combination of two or more. Examples include water-soluble resins such as carboxyl group-containing resins and phenolic hydroxyl group-containing resins. Among these, carboxyl group-containing resins and phenolic hydroxyl group-containing resins are preferred due to their excellent developability, and carboxyl group-containing resins are more preferred. The presence of carboxyl groups in the carboxyl group-containing resin makes it alkali-developable. Furthermore, from the viewpoint of photosensitivity, it is preferable to have an ethylenically unsaturated double bond in the molecule in addition to the carboxyl group, but only carboxyl group-containing resins without ethylenically unsaturated double bonds may be used. The ethylenically unsaturated double bond is preferably derived from acrylic acid, methacrylic acid, or their derivatives. When using only carboxyl group-containing resins without ethylenically unsaturated double bonds, it is necessary to use a compound having multiple ethylenically unsaturated groups in the molecule, i.e., a photopolymerizable monomer, in order to make the composition photocurable. Specific examples of carboxyl group-containing resins include the following compounds (which may be either oligomers or polymers). In this specification, (meth)acrylate is a general term referring to acrylates, methacrylates, and mixtures thereof, and the same applies to other similar expressions.

[0038] (1) A carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth)acrylic acid with an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, or isobutylene.

[0039] (2) A carboxyl group-containing urethane resin obtained by polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, and diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups.

[0040] (3) A partially acid anhydride modified product of a reaction between diisocyanate and a bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, or biphenol type epoxy resin, and a monocarboxylic acid compound having an ethylenically unsaturated double bond such as (meth)acrylic acid, as well as a carboxyl group-containing photosensitive urethane resin obtained by polyaddition reactions of carboxyl group-containing dialcohol compounds and diol compounds.

[0041] (4) A carboxyl group-containing photosensitive urethane resin obtained by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as hydroxyalkyl (meth)acrylate, during the synthesis of the resin of (2) or (3) above, and then (meth)acrylicating the terminal (meth)acrylic.

[0042] (5) A carboxyl group-containing photosensitive urethane resin in which a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule is added to the resin of (2) or (3) above during synthesis and then (meth)acrylicated at the terminal.

[0043] (6) A carboxyl group-containing photosensitive resin obtained by reacting a bifunctional or polyfunctional (solid) epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride to the hydroxyl groups present in the side chain.

[0044] (7) A carboxyl group-containing photosensitive resin obtained by reacting a polyfunctional epoxy resin, in which the hydroxyl groups of a bifunctional (solid) epoxy resin are further epoxidized with epichlorohydrin, with (meth)acrylic acid, and then adding a dibasic acid anhydride to the resulting hydroxyl groups.

[0045] (8) A carboxyl group-containing polyester resin obtained by reacting a bifunctional oxetane resin with dicarboxylic acids such as adipic acid, phthalic acid, and hexahydrophthalic acid, and adding dibasic acid anhydrides such as phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride to the resulting primary hydroxyl groups.

[0046] (9) A carboxyl group-containing photosensitive resin obtained by reacting an epoxy compound having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol, and an unsaturated group-containing monocarboxylic acid such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl group of the resulting reaction product with a polybasic acid anhydride such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic acid.

[0047] (10) A carboxyl group-containing photosensitive resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide, reacting the reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0048] (11) A carboxyl group-containing photosensitive resin obtained by reacting a reaction product obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0049] (12) A carboxyl group-containing photosensitive resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to the resins of (1) to (11) above. In this specification, (meth)acrylate is a general term referring to acrylates, methacrylates, and mixtures thereof, and the same applies to other similar expressions.

[0050] Among the carboxyl group-containing photosensitive resins described above, the photosensitive resin of (6) in which a novolac-type epoxy resin is used as the epoxy resin, the photosensitive resin of (7) in which a bisphenol-type epoxy resin is used as the epoxy resin, and the photosensitive resin of (12) can be preferably used. In particular, a combination of at least two of the aforementioned (6), (7), and (12) can be more preferably used, and a combination of three can be even more preferably used.

[0051] The aforementioned (6) is preferably present in a proportion of 10 to 80% by mass, more preferably 10 to 60% by mass, and even more preferably 10 to 40% by mass, relative to the total carboxyl group-containing resin. The aforementioned (7) is preferably contained in a proportion of 20 to 70% by mass, more preferably 30 to 60% by mass, and even more preferably 40 to 55% by mass, relative to the total carboxyl group-containing resin. The aforementioned (12) is preferably included in a proportion of 20 to 40% by mass, and more preferably in a proportion of 25 to 40% by mass, relative to the total carboxyl group-containing resin.

[0052] These carboxyl group-containing resins are not limited to those listed above and may be used individually or in combination of multiple types.

[0053] The acid value of the carboxyl group-containing resin is preferably 40 to 150 mg KOH / g. An acid value of 40 mg KOH / g or higher improves alkaline development. Furthermore, an acid value of 150 mg KOH / g or lower facilitates the creation of good resist patterns. More preferably, the acid value is 50 to 130 mg KOH / g.

[0054] The weight-average molecular weight of carboxyl group-containing resins varies depending on the resin skeleton, but is generally preferably between 2,000 and 150,000. A weight-average molecular weight of 2,000 or higher can improve tack-free performance and resolution. Furthermore, a weight-average molecular weight of 150,000 or lower can improve developability and storage stability. More preferably, it is between 5,000 and 30,000. The weight-average molecular weight can be measured by gel permeation chromatography (GPC).

[0055] The amount of carboxyl group-containing resin blended in the curable resin composition is preferably 20 to 60% by mass in terms of solid content. A concentration of 20% by mass or more improves the strength of the coating film. A concentration of 60% by mass or less results in appropriate viscosity and improved printability. More preferably, the concentration is 25 to 50% by mass.

[0056] From the viewpoint of printability and adhesion of the marking ink, the total amount of curable resin in the curable resin composition is preferably 20 to 80% by mass, and more preferably 30 to 70% by mass, based on solid content.

[0057] If the curable resin composition for forming the cured product of the present invention contains a carboxyl group-containing resin, a photopolymerizable monomer, or an oligomer, it may also contain a photopolymerization initiator for reaction by exposure. Any known photopolymerization initiator can be used.

[0058] Examples of photopolymerization initiators include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphate. Sphin oxides, bisacyl phosphine oxides such as bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinate methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenyl Monoacyl phosphine oxides such as isopropyl phosphinate and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; ethyl phenyl(2,4,6-trimethylbenzoyl)phosphineate, 1-hydroxycyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methyl-propan-1-one Hydroxyacetophenones such as 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzoins such as benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; benzoin alkyl ethers; benzophenones such as benzophenone, p-methylbenzophenone, Michla's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone;Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-bu Acetophenones such as tanone and N,N-dimethylaminoacetophenone; thioxanthones such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, and 2-amylanthraquinone Anthraquinones such as 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethylbenzoate ethyl ester; 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)], etanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetylo Examples of photopolymerization initiators include oxime esters such as xime; titanosenes such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium; phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. These photopolymerization initiators may be used individually or in combination of two or more.

[0059] Commercially available α-aminoacetophenone-based photopolymerization initiators include Omnirad 907, 369, 369E, and 379 from IGM Resins. Commercially available acylphosphine oxide-based photopolymerization initiators include Omnirad 819 from IGM Resins. Commercially available oxime ester-based photopolymerization initiators include Irgacure OXE01 and OXE02 from BASF Japan Ltd., N-1919 from ADEKA Corporation, ADEKA Arclus NCI-831 and NCI-831E, and TR-PBG-304 from Changzhou Strong Electronic New Materials Co., Ltd.

[0060] Other examples include carbazole oxime ester compounds described in Japanese Patent Publication No. 2004-359639, Japanese Patent Publication No. 2005-097141, Japanese Patent Publication No. 2005-220097, Japanese Patent Publication No. 2006-160634, Japanese Patent Publication No. 2008-094770, Japanese Patent Publication No. 2008-509967, Japanese Patent Publication No. 2009-040762, and Japanese Patent Publication No. 2011-80036.

[0061] When the curable resin composition contains a carboxyl group-containing resin, the amount of photopolymerization initiator is preferably 1 to 30 parts by mass per 100 parts by mass of the carboxyl group-containing resin, based on solid content. When the amount is 1 part by mass or more, the photocurability of the curable resin composition is good, and the film properties such as chemical resistance are also good. When the amount is 30 parts by mass or less, an outgassing effect is obtained, and furthermore, light absorption on the surface of the cured film is good, and the deep curing ability is less likely to decrease. More preferably, the amount is 2 to 25 parts by mass.

[0062] Furthermore, in the present invention, a photoinitiator or sensitizer may be used in combination with the photopolymerization initiator. Examples of photoinitiators or sensitizers include benzoin compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, tertiary amine compounds, and xanthone compounds. In particular, it is preferable to use thioxanthone compounds such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, and 4-isopropylthioxanthone. The inclusion of thioxanthone compounds can improve deep curing properties. These compounds can sometimes be used as photoinitiators, but it is preferable to use them in combination with a photoinitiator. In addition, one type of photoinitiator or sensitizer may be used alone, or two or more types may be used in combination.

[0063] These photopolymerization initiators, photoinitiators, and sensitizers absorb specific wavelengths, which can sometimes lead to reduced sensitivity and function as UV absorbers. However, they are not used solely for the purpose of improving the sensitivity of curable resin compositions. By absorbing light of specific wavelengths as needed, they can enhance the photoreactivity of the surface, change the line shape and apertures of the resist pattern to vertical, tapered, or reverse tapered shapes, and improve the accuracy of line width and aperture diameter.

[0064] Furthermore, if the curable resin composition for forming the cured product of the present invention contains a thermosetting resin, it may also contain a thermosetting catalyst to promote curing. Examples of thermosetting catalysts include 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 dihydrazide and sebacate dihydrazide; and phosphorus compounds such as triphenylphosphine. Examples of commercially available products include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names for imidazole compounds) manufactured by Shikoku Chemicals, Inc., and U-CAT 3513N (trade name for a dimethylamine compound), DBU, DBN, and U-CAT SA 102 (all bicyclic amidine compounds and their salts) manufactured by Sunapro Co., Ltd.

[0065] The compounds are not limited to those described above, but may be any compounds that act as a thermosetting catalyst for epoxy resins or oxetane compounds, or that promote the reaction between at least one of an epoxy group and an oxetanyl group and a carboxyl group, and may be used alone or in combination of two or more. In addition, S-triazine derivatives such as guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine isocyanuric acid adduct may be used, and preferably these compounds that also function as adhesion promoters are used in combination with the thermosetting catalyst.

[0066] The thermosetting catalysts described above can be used individually or in combination of two or more. From the viewpoint of storage stability of the photosensitive resin composition and heat resistance of the cured film, the amount of thermosetting catalyst to be added is preferably 0.01 to 8 parts by mass, and more preferably 0.05 to 5 parts by mass, per 100 parts by mass of carboxyl group-containing resin, in terms of solid content, when the curable resin composition contains a carboxyl group-containing resin.

[0067] <Inorganic filler> The cured product of the present invention is obtained by curing a curable resin composition containing amorphous silica as an inorganic filler. The inclusion of amorphous silica significantly improves the printability when printing marking ink onto the surface of the cured product, as well as the adhesion and visibility of the marker after printing. While the reason for this is not entirely clear, it is thought to be as follows: Amorphous silica has lower surface smoothness compared to crystalline silica, and it is believed that this improves printability and adhesion due to its anchoring effect. In this invention, amorphous silica refers to silica other than crystalline silica (including fine crystalline silica), which does not have the long-range order of crystalline silica, but does have short-range order. Thermodynamically, this is a non-equilibrium metastable state. Commonly known and conventional amorphous silica can be used, such as silica gel and diatomaceous earth. Furthermore, any amorphous silica may be synthetic silica.

[0068] From the viewpoint of the applicability of marking ink and adhesion to the marking ink during curing, amorphous silica is preferably such that it has an oil absorption capacity of 180 to 350 ml / 100g. Such amorphous silica is porous, and it is presumed that the absorption of oil from organic solvents, etc., during curing and drying results in a denser state of amorphous silica and other extender pigments, thereby improving the applicability and adhesion of the marking ink. An oil absorption capacity of 200 to 300 ml / 100g is more preferable. In this invention, the oil absorption capacity refers to the amount measured in accordance with "JIS K5101-13-1:2004 Pigment Test Methods - Part 13: Oil Absorption - Section 1: Refined Linseed Oil Method".

[0069] Amorphous silica can be of known and conventional types, and may be synthetic or natural. Surface treatment may or may not be applied. The type of surface treatment is the same as that for the extender pigments mentioned above. Examples of products include ACEMATT 82, ACEMATT 790, ACEMATT OK 412, and ACEMATT OK 500 (all manufactured by EVONIK DEGUSSA).

[0070] The amorphous silica described above may be surface-treated to improve its dispersibility in the curable resin composition. Using surface-treated amorphous silica can suppress aggregation. The surface treatment method is not particularly limited, and any known and conventional method may be used, but it is preferable to treat the surface of the amorphous silica with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group.

[0071] As coupling agents, silane-based, titanate-based, aluminate-based, and zircoaluminate-based coupling agents can be used. Among these, silane-based coupling agents are preferred. Examples of such silane-based coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N-(2-aminomethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane, which can be used alone or in combination. It is preferable that these silane-based coupling agents are pre-immobilized on the surface of the filler by adsorption or reaction.

[0072] The average particle size (D50) of amorphous silica can preferably be 0.1 to 10 μm, and more preferably 1 to 5 μm. The average particle size refers to the particle size at 50% volume accumulation, obtained using the laser diffraction scattering particle size distribution method. Furthermore, the average particle size of amorphous silica refers to the value measured in the manner described above for silica before preparing the curable resin composition (pre-mixing, kneading).

[0073] From the viewpoint of printability and adhesion of the marking ink, the amount of amorphous silica blended in the curable resin composition is preferably 2 to 30% by mass, and more preferably 5 to 20% by mass, based on the solid content of the entire curable resin composition.

[0074] In addition to the amorphous silica mentioned above, other inorganic fillers may be added to the curable resin composition as needed to increase the physical strength of the cured product. Known inorganic fillers can be used, and examples include talc, mica, aluminum oxide, calcium oxide, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, fly ash, dewatered sludge, kaolin, clay, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, hydrotalcite, aluminum silicate, magnesium silicate, calcium silicate, wollastonite, potassium titanate, magnesium sulfate, calcium sulfate, magnesium phosphate, sepiolite, zonolite, boron nitride, aluminum borate, silica balloons, glass flakes, glass balloons, steelmaking slag, copper, iron, iron oxide, Sendust, Alnico magnets, magnetic powders such as various ferrites, cement, glass powder, Neuburg silica, antimony trioxide, magnesium oxysulfate, hydrated aluminum, hydrated gypsum, alum, and barium sulfate. Other inorganic fillers may be used individually or in combination of two or more types.

[0075] The inorganic fillers described above preferably have an average particle size (D50) of 0.1 to 200 μm, and more preferably 1 to 10 μm, from the viewpoint of dispersibility. Furthermore, similar to amorphous silica, they may be surface-treated from the viewpoint of dispersibility.

[0076] The total amount of inorganic filler combined with amorphous silica is preferably 20 to 70% by mass, and more preferably 40 to 60% by mass, based on solid content relative to the entire curable resin composition. This improves the ability of the curable resin composition to prevent deterioration of adhesion and its resistance to thermal cycling, resulting in improved adhesion to the marking ink.

[0077] <Other ingredients> In addition to the components described above, the curable resin composition according to the present invention may optionally contain other components such as colorants, elastomers, mercapto compounds, urethane catalysts, thixonating agents, adhesion promoters, block copolymers, chain transfer agents, polymerization inhibitors, copper damage inhibitors, antioxidants, rust inhibitors, thickeners such as organic bentonite and montmorillonite, defoaming agents and leveling agents such as silicone-based, fluorine-based, and polymer-based defoamers, and flame retardants such as phosphinates, phosphate ester derivatives, and phosphazene compounds. These can be those known in the field of electronic materials.

[0078] Organic solvents may be added to the curable resin composition from the viewpoint of ease of preparation and applicability. As organic solvents, known and commonly used organic solvents can be used, such as ketones like methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons like toluene, xylene, and tetramethylbenzene; glycol ethers like cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, and tripropylene glycol monomethyl ether; esters like ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons like octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. These organic solvents can be used individually or in combination of two or more.

[0079] The amount of organic solvent in a curable resin composition can be appropriately changed depending on the materials constituting the curable resin composition. For example, if the curable resin composition contains a carboxyl group-containing resin, the amount of organic solvent can be 20 to 300 parts by mass per 100 parts by mass of the carboxyl group-containing resin (solid content).

[0080] The curable resin composition may be used as a dry film or as a liquid. When used as a liquid, it may be a one-component or two-component or more-component composition.

[0081] [Photosensitive resin composition] The photosensitive resin composition according to the present invention contains (A) a carboxyl group-containing resin, (B) a photopolymerizable monomer, and (C) a thermosetting component as essential components. The following describes each component constituting the photosensitive resin composition according to the present invention.

[0082] <(A) Carboxyl group-containing resin> The photosensitive resin composition according to the present invention contains, as (A) carboxyl group-containing resins, three types of carboxyl group-containing resins in specific proportions: (A1) a carboxyl group-containing resin having a novolac skeleton, (A2) a carboxyl group-containing resin having a bisphenol skeleton, and (A3) an unsaturated basic acid copolymer type carboxyl group-containing resin. In the present invention, by containing the above-mentioned three specific photosensitive resins as carboxyl group-containing resins in specific proportions, it is possible to obtain a photosensitive resin composition that can suppress contamination of the plating solution and also suppress plating defects while satisfying the properties required for solder resist, such as heat resistance and insulation reliability. The reason for this is not clear, but it can be inferred as follows.

[0083] As described in Patent Document 4 above, when a carboxyl group-containing resin having a bisphenol skeleton and an unsaturated basic acid copolymer type carboxyl group-containing resin are used in combination as the photosensitive resin, the resin has high hydrophobicity and a large molecular weight, resulting in excellent insulation reliability and heat resistance for PCBT and other materials. However, the copolymer resin component among the uncured resin components dissolved in the developer solution precipitates in the water bath during the washing process after development and re-adheres to the conductive portion (copper) of the substrate. This deposit is thought to be the cause of plating defects in the subsequent plating process. On the other hand, when a photosensitive resin with excellent heat resistance and crack resistance (carboxyl group-containing resin having a bisphenol skeleton or novolac skeleton), as described in Patent Document 3, is used as the photosensitive resin, although there is almost no precipitation of development residue into the water bath as described above, uncured resin components and unreacted photopolymerizable monomers contained in the cured film of the photosensitive resin composition dissolve into the electroless plating bath, contaminating the plating bath. Therefore, by using the three carboxyl group-containing resins described above in specific proportions, it is possible to achieve a high level of balance between the overall hydrophobicity of the photosensitive resin (suppression of deposition in the water bath) and suppression of elution into the plating bath. As a result, it is believed that both the occurrence of plating defects and contamination of the plating solution can be suppressed while satisfying the properties required of solder resist, such as heat resistance and insulation reliability.

[0084] (A1) As a carboxyl group-containing resin having a novolac skeleton, a carboxyl group-containing photosensitive resin (A1a) is obtained by reacting a polyfunctional epoxy resin such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A cresol novolac type epoxy resin, or dicyclopentadiene cresol novolac type epoxy resin with (meth)acrylic acid and adding dibasic acid anhydrides such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chains. A polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of the above polyfunctional epoxy resin with epichlorohydrin and reacting the resulting hydroxyl groups with (meth)acrylic acid. Examples of carboxyl group-containing photosensitive resins include (A1b) a carboxyl group-containing photosensitive resin with the addition of a basic acid anhydride, (A1c) a carboxyl group-containing photosensitive resin obtained by adding a cyclic ether such as ethylene oxide or a cyclic carbonate such as propylene carbonate to a polyfunctional phenol compound such as a novolac resin, partially esterifying the resulting hydroxyl groups with (meth)acrylic acid, and reacting the remaining hydroxyl groups with a polybasic acid anhydride, and a carboxyl group-containing photosensitive resin obtained by further adding a compound having one epoxy group and one or more (meth)acryloyl groups in its molecule, such as glycidyl (meth)acrylate or α-methylglycidyl (meth)acrylate, to any of the resins A1a to A1c above. In the present invention, cresol novolac type carboxyl group-containing resins are preferred because they have superior solder heat resistance compared to phenol novolac type carboxyl group-containing resins. In this specification, "(meth)acrylate" is used as a general term for acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions. Furthermore, the term "(meth)acryloyl group" is used as a general term encompassing acryloyl group, methacryloyl group, and both, and the same applies to other similar expressions.

[0085] (A2) Examples of carboxyl group-containing resins having a bisphenol skeleton include a carboxyl group-containing photosensitive resin (A2a) obtained by reacting a bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, or bisphenol S type epoxy resin with (meth)acrylic acid and adding a polybasic acid anhydride to the resulting hydroxyl groups; a carboxyl group-containing photosensitive resin (A2b) obtained by reacting a polyfunctional epoxy resin, in which the hydroxyl groups of the above bifunctional epoxy resin are further epoxidized with epichlorohydrin, with (meth)acrylic acid and adding a polybasic acid anhydride to the resulting hydroxyl groups; and a carboxyl group-containing photosensitive resin obtained by further adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule, such as glycidyl (meth)acrylate or α-methylglycidyl (meth)acrylate, to the resin of A2a or A2b.

[0086] The carboxyl group-containing resins (A1) and (A2) described above have numerous free carboxyl groups in the side chains of the backbone polymer, making them developable with an alkaline aqueous solution. The acid value of these carboxyl group-containing resins (A1) and (A2) is preferably 40 to 200 mg KOH / g. When the acid value of the carboxyl group-containing resins A1 and A2 is 40 to 200 mg KOH / g, alkaline development is facilitated, dissolution of the exposed areas by the developer is suppressed, and the drawing of fine resist patterns is made easier. More preferably, it is 45 to 120 mg KOH / g.

[0087] The weight-average molecular weight of the carboxyl group-containing resins (A1) and (A2) described above varies depending on the resin skeleton, but from the viewpoint of moisture resistance (solubility in water), resolution, and developability of the coating film after exposure, it is generally preferably 2,000 to 150,000, and more preferably 5,000 to 100,000. Note that the weight-average molecular weight refers to the value on a standard polystyrene basis measured by gel permeation chromatography (GPC).

[0088] Next, (A3) the unsaturated basic acid copolymer type carboxyl group-containing resin will be described. The carboxyl group-containing resin of (A3) is obtained by copolymerizing a (meth)acrylic acid ester with a compound having one unsaturated group and at least one carboxyl group in one molecule. Examples of (meth)acrylic acid esters include alkyl (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, and hexyl (meth)acrylate; hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and caprolactone-modified 2-hydroxyethyl (meth)acrylate; and glycol-modified (meth)acrylates such as methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, isooctyloxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate. These may be used individually or in combination of two or more.

[0089] Furthermore, examples of compounds having one unsaturated group and at least one carboxyl group in one molecule include acrylic acid, methacrylic acid, modified unsaturated monocarboxylic acids in which the chain between the unsaturated group and the carboxylic acid is extended, such as β-carboxyethyl (meth)acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, unsaturated monocarboxylic acids having an ester bond due to lactone modification, modified unsaturated monocarboxylic acids having an ether bond, and compounds such as maleic acid that contain two or more carboxyl groups in the molecule. These may be used individually or in combination of two or more.

[0090] In the present invention, as the (A3) unsaturated basic acid copolymer type carboxyl group-containing resin, a resin obtained by introducing unsaturated groups into the resin by reacting some of the acid groups of the above-mentioned unsaturated basic acid copolymer resin (i.e., a copolymer resin obtained by copolymerizing an (meth)acrylic acid ester with a compound having one unsaturated group and at least one carboxyl group in one molecule) with the epoxy groups of an alicyclic epoxy group-containing unsaturated compound can be preferably used. By using the unsaturated basic acid copolymer type carboxyl group-containing resin in combination with the above-mentioned carboxyl group-containing resins (A1) and (A2) in a specific ratio, the PCBT properties are further improved.

[0091] As unsaturated compounds containing alicyclic epoxy groups that react with some of the acid groups of the unsaturated basic acid copolymer resin described above, compounds having one radically polymerizable unsaturated group and one alicyclic epoxy group in one molecule, for example, compounds having both an alicyclic epoxy group and an acrylic group, such as 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylethyl acrylate, and 3,4-epoxycyclohexylbutyl acrylate. These may be used individually or in combination of two or more.

[0092] In addition to the compounds having both alicyclic epoxy groups and acrylic groups as described above, other aliphatic epoxy group-containing unsaturated compounds such as glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, and allyl glycidyl ether may also be used in combination.

[0093] The weight-average molecular weight of the carboxyl group-containing resin described in (A3) above varies depending on the resin skeleton, but from the viewpoint of moisture resistance (solubility in water), resolution, and developability of the coating film after exposure, it is generally preferably 3,000 to 100,000, and more preferably 5,000 to 50,000.

[0094] The photosensitive resin composition of the present invention contains a total blending amount of carboxyl group-containing resin (A1) and carboxyl group-containing resin (A2) of 60 to 80% by mass relative to the total amount of carboxyl group-containing resin (A). Furthermore, the blending amount of carboxyl group-containing resin (A3) is 40 to 20% by mass relative to the total amount of carboxyl group-containing resin (A). By including these three types of carboxyl group-containing resins in specific proportions, it is possible to suppress both plating solution contamination and plating defects while satisfying the properties required for solder resists, such as insulation reliability. Note that the blending amounts of each carboxyl group-containing resin are calculated on a solid content basis (the same applies hereinafter).

[0095] From the viewpoint of gold plating resistance, the total amount of carboxyl group-containing resin (A1) and carboxyl group-containing resin (A2) is preferably 65 to 75% by mass relative to the total amount of carboxyl group-containing resin (A).

[0096] Regarding the blending ratio of each carboxyl group-containing resin (A1) to (A3) above, from the viewpoint of suppressing non-adhesion of gold plating, the amount of carboxyl group-containing resin (A1) is preferably 10 to 60% by mass, and more preferably 10 to 40% by mass, relative to the total amount of carboxyl group-containing resin (A).

[0097] Furthermore, from the viewpoint of suppressing the re-adhesion of developing residue to the substrate, the amount of carboxyl group-containing resin (A) blended is preferably 20 to 60% by mass, and more preferably 40 to 60% by mass, relative to the total amount of carboxyl group-containing resin (A).

[0098] Furthermore, the amount of carboxyl group-containing resin (A3) blended is preferably 40 to 20% by mass relative to the total amount of carboxyl group-containing resin (A), from the viewpoint of suppressing PCT resistance and gold plating abnormalities.

[0099] (A) The amount of carboxyl group-containing resin blended is preferably 20 to 60% by mass of the total photosensitive resin composition. A concentration of 20% by mass or more can improve the strength of the coating film. A concentration of 60% by mass or less results in appropriate viscosity and improved processability. More preferably, the concentration is 25 to 50% by mass.

[0100] <(B) Photopolymerizable monomers> The (B) photopolymerizable monomer contained in the photosensitive resin composition is a monomer having an ethylenically unsaturated double bond. As the (B) photopolymerizable monomer, those shown in the curable resin composition described above can be used.

[0101] The amount of (B) photopolymerizable monomer in the photosensitive resin composition is preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass, per 100 parts by mass of the carboxyl group-containing resin, on a solid content basis.

[0102] <Photopolymerization initiator> The photosensitive resin composition according to the present invention may contain a photopolymerization initiator in order to react the above-mentioned (A) carboxyl group-containing resin and (B) photopolymerizable monomer by exposure. As the photopolymerization initiator, those indicated in the above-mentioned curable resin composition can be used.

[0103] The amount of photopolymerization initiator added is preferably 1 to 20 parts by mass per 100 parts by mass of (A) carboxyl group-containing resin, based on solid content. When the amount is 1 part by mass or more, the photocurability of the photosensitive resin composition is good, and the film properties such as chemical resistance are also good. When the amount is 20 parts by mass or less, an outgassing effect is obtained, and furthermore, light absorption on the surface of the cured film is good, and the deep curing ability is less likely to decrease. More preferably, the amount is 2 to 15 parts by mass.

[0104] Furthermore, in the present invention, a photoinitiator or sensitizer may be used in combination with the photopolymerization initiator. As the photoinitiator or sensitizer, those indicated in the curable resin composition described above can be used.

[0105] <(C) Thermosetting component> The photosensitive resin composition according to the present invention comprises (A) a carboxyl group-containing resin and (B) a photopolymerizable monomer, as well as (C) a thermosetting component. The inclusion of the thermosetting component improves the barrier properties of the cured film in subsequent processes (e.g., etching resistance), and enables a high level of balance between resolution and peelability. As the (C) thermosetting component, the "curable resin" indicated in the above-described curable resin composition can be used.

[0106] Furthermore, in the photosensitive resin composition according to the present invention, epoxy resins having an isocyanuryl ring can be preferably used from the viewpoint of achieving both resolution and release properties. Examples of epoxy resins having an isocyanuryl ring include difunctional epoxy isocyanurate ester compounds such as 1,3-bis(2,3-epoxypropyl)-5-(2-propenyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione; 1,3,5-tris(2,3-epoxypropyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-trione Trifunctional epoxy isopropyls such as ris(2,3-epoxy-2-methylpropyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris(3,4-epoxybutyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and 1,3,5-tris(4,5-epoxypentyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione. An anurat ester compounds include polyfunctional epoxy isocyanurate ester compounds with four or more functions, such as 1,3,5-tris{2-[2,2-bis(2,3-epoxypropyloxymethyl)butyloxycarbonyl]ethyl}-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and those containing trifunctional epoxy isocyanurate ester compounds are preferred, and those containing 1,3,5-tris(2,3-epoxypropyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris(3,4-epoxybutyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, or 1,3,5-tris(4,5-epoxypentyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione are particularly preferred.

[0107] Examples of commercially available epoxy resins having an isocyanuric ring include TEPIC-PAS B26L, TEPIC-PAS B22, TEPIC-VL, TEPIC-UC, TEPIC-G, TEPIC-S, TEPIC-SP, and TEPIC-SS, all manufactured by Nissan Chemical Corporation.

[0108] (C) The amount of thermosetting component to be blended is preferably 0.8 to 2.5 mol, and more preferably 1.0 to 2.0 mol, of the number of functional groups of the (C) thermosetting component that react with (A) the carboxyl group-containing resin per 1.0 mol of carboxyl groups contained therein.

[0109] In particular, when (C) epoxy resin is used as the thermosetting component, it is preferable that the epoxy groups of the epoxy resin be 1.0 to 2.0 mol per 1.0 mol of carboxyl groups of (A) carboxyl group-containing resin. By setting the amount to 1 mol or more, it is possible to prevent the residue of carboxyl groups in the cured film and obtain good heat resistance, alkali resistance, electrical insulation, etc. Furthermore, by setting the above blending amount to 2 mol or less, it is possible to prevent low molecular weight cyclic (thio) ether groups from remaining in the dried coating film and ensure good strength of the cured film, etc.

[0110] <Thermosetting catalyst> The photosensitive resin composition may also contain a thermosetting catalyst to promote the curing of the (C) thermosetting component described above. As the thermosetting catalyst, one of those indicated in the curable resin composition described above can be used.

[0111] The above-mentioned thermosetting catalysts can be used individually or in combination of two or more. From the viewpoint of storage stability of the photosensitive resin composition and heat resistance of the cured film, the amount of thermosetting catalyst added is preferably 0.01 to 8 parts by mass, and more preferably 0.05 to 5 parts by mass, per 100 parts by mass of (A) carboxyl group-containing resin, on a solid content basis.

[0112] <(D) Inorganic filler> The photosensitive resin composition according to the present invention may contain (D) inorganic fillers as needed to increase the physical strength of the cured film. Known fillers can be used as inorganic fillers, and examples include silica, talc, mica, aluminum oxide, calcium oxide, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, fly ash, dewatered sludge, kaolin, clay, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, hydrotalcite, aluminum silicate, magnesium silicate, calcium silicate, wollastonite, potassium titanate, magnesium sulfate, calcium sulfate, magnesium phosphate, sepiolite, zonolite, boron nitride, aluminum borate, silica balloons, glass flakes, glass balloons, steelmaking slag, copper, iron, iron oxide, Sendust, Alnico magnets, magnetic powders such as various ferrites, cement, glass powder, Neuburg siliceous earth, diatomaceous earth, antimony trioxide, magnesium oxysulfate, hydrated aluminum, hydrated gypsum, alum, and barium sulfate. Other inorganic fillers may be used individually or in combination of two or more types.

[0113] Among the above, silica, talc, and barium sulfate are preferred. The silica may be amorphous, crystalline, or a mixture thereof. Amorphous (fused) silica is particularly preferred.

[0114] The inorganic filler used is preferably of average particle size (D50) of 0.1 to 100 μm, and more preferably of 0.1 to 50 μm, from the viewpoint of dispersibility and other factors. The average particle size refers to the particle size at 50% volume cumulative, obtained using the laser diffraction scattering particle size distribution method. Furthermore, the average particle size of the filler refers to the value measured as described above for the filler before preparing the photosensitive resin composition (pre-stirring, kneading).

[0115] The amount of inorganic filler in the photosensitive resin composition is preferably 1 to 500 parts by mass, and more preferably 10 to 300 parts by mass, based on solid content, per 100 parts by mass of carboxyl group-containing resin. This further improves the adhesion reduction prevention and thermal cycle resistance of the photosensitive resin composition.

[0116] The inorganic filler described above may be surface-treated to improve its dispersibility in the photosensitive resin composition. Using a surface-treated inorganic filler can suppress aggregation. The surface treatment method is not particularly limited, and any known and conventional method may be used, but it is preferable to treat the surface of the inorganic filler with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group.

[0117] As the coupling agent, those indicated in the curable resin composition described above can be used. It is preferable that these silane-based coupling agents are pre-immobilized on the surface of the inorganic filler by adsorption or reaction. Here, the amount of coupling agent to be treated per 100 parts by mass of inorganic filler is preferably 0.5 to 10 parts by mass.

[0118] <Other ingredients> In addition to the components described above, the photosensitive resin composition according to the present invention may also use other components as indicated by "other components" in the curable resin composition described above, as needed.

[0119] The photosensitive resin composition of the present invention may contain an organic solvent from the viewpoint of ease of preparation and applicability. As the organic solvent, those indicated in the curable resin composition described above can be used.

[0120] The amount of organic solvent blended in the photosensitive resin composition can be appropriately changed depending on the materials constituting the photosensitive resin composition. For example, it can be 30 to 300 parts by mass per 100 parts by mass of (A) carboxyl group-containing resin (solids). Note that the amount of organic solvent blended here includes the organic solvent contained in the varnish when resins such as (A) carboxyl group-containing resin are used as varnish.

[0121] The photosensitive resin composition of the present invention may be used as a dry film or as a liquid. Furthermore, when used as a liquid, it may be a one-component or two-component or more-component composition.

[0122] <Dry film> The curable resin composition described above and the photosensitive resin composition of the present invention can also be in the form of a dry film comprising a first film and a resin layer formed on the first film consisting of the curable resin composition or the photosensitive resin composition. In the dry film of the present invention, the first film refers to a film that is at least adhered to the resin layer when it is laminated onto a substrate such as a substrate by heating or the like so that the side with the resin layer formed on the dry film consisting of the curable resin composition or the photosensitive resin composition is in contact with the substrate. The first film may be peeled off from the resin layer in a process after lamination. In particular, in the present invention, it is preferable to peel it off from the resin layer in a process after exposure.

[0123] To produce a dry film, the above-mentioned curable resin composition or photosensitive resin composition is diluted with an organic solvent to adjust to an appropriate viscosity, and then applied to a first film to a uniform thickness using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, etc., and dried at a temperature of 50 to 130°C for 1 to 30 minutes to obtain the film. There are no particular restrictions on the coated film thickness, but generally, the film thickness after drying is appropriately selected within the range of 1 to 150 μm, preferably 10 to 60 μm.

[0124] The first film can be any known film without particular limitations, and for example, films made of thermoplastic resins such as polyester films (polyethylene terephthalate, polyethylene naphthalate, etc.), polyimide films, polyamide-imide films, polypropylene films, and polystyrene films can be suitably used. Among these, polyester films are preferred from the viewpoint of heat resistance, mechanical strength, and ease of handling. Laminates of these films can also be used as the first film.

[0125] Furthermore, from the viewpoint of improving mechanical strength, the thermoplastic resin film described above is preferably a film stretched in one or two axes.

[0126] The thickness of the first film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0127] It is preferable to form a resin layer of the curable resin composition or the photosensitive resin composition on the first film, and then laminate a peelable second film onto the surface of the resin layer for purposes such as preventing dust from adhering to the surface of the resin layer. In the dry film according to the present invention, the second film refers to a film that is peeled off from the resin layer before lamination when integrally forming the dry film by lamination by heating or the like so that the resin layer side of the dry film is in contact with a substrate such as a substrate.

[0128] As the second film that can be peeled off from the resin layer, for example, polyethylene film, polytetrafluoroethylene film, polypropylene film, surface-treated paper, etc., it is sufficient that the adhesive force between the resin layer and the second film is less than the adhesive force between the resin layer and the first film when the second film is peeled off.

[0129] The thickness of the second film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0130] <Method for manufacturing hardened products> The cured product of the present invention can be obtained by curing the resin layer of the curable resin composition or dry film described above. For example, the curable resin composition is adjusted to a viscosity suitable for the coating method using the above-mentioned organic solvent, and then applied to the surface of a substrate such as a substrate by methods such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating. After that, the organic solvent contained in the composition is evaporated and dried (pre-dried) at a temperature of 60 to 100°C to form a tack-free resin layer. In the case of a dry film, the resin layer is bonded to the substrate using a laminator or the like so that the resin layer is in contact with the substrate, and then the carrier film is peeled off to form a resin layer on the substrate.

[0131] The above-mentioned substrates include printed circuit boards and flexible printed circuit boards with circuits pre-formed using copper, etc., as well as materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / nonwoven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, copper-clad laminates for high-frequency circuits using fluororesin / polyethylene / polyphenylene ether, polyphenylene oxide / cyanate, etc., and can be described as copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafers, etc.

[0132] When the film is in the form of a dry film, it is preferable to laminate it onto the substrate under pressure and heat using a vacuum laminator or the like. By using such a vacuum laminator, even if the surface of the circuit board is uneven when a circuit-formed substrate is used, the dry film adheres closely to the circuit board, preventing the inclusion of air bubbles and improving the ability to fill in depressions on the substrate surface. The pressurizing conditions are preferably around 0.1 to 2.0 MPa, and the heating conditions are preferably 40 to 120°C.

[0133] When the cured resin composition contains an organic solvent, it is preferable to apply the cured resin composition to the substrate surface and then perform volatilization drying. Volatilization drying can be performed using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. (a method in which hot air inside the dryer is brought into countercurrent contact with a heat source that uses steam to heat the air, or a method in which hot air is blown onto the substrate from a nozzle).

[0134] After forming a resin layer on a substrate, it is selectively exposed to active energy rays through a photomask with a predetermined pattern, and the unexposed areas are developed with a dilute alkaline aqueous solution (for example, a 0.3-3% by mass sodium carbonate aqueous solution) to form the pattern of the cured product. In the case of a dry film, after exposure, the first film is peeled off the dry film and developed to form a patterned cured product on the substrate. In the case of a dry film, if the properties are not impaired, the first film may be peeled off the dry film before exposure, and the exposed resin layer may be exposed and developed.

[0135] The exposure machine used for the above-mentioned active energy ray irradiation can be any device equipped with a high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, mercury short-arc lamp, etc., that irradiates ultraviolet light in the range of 350 to 450 nm. Furthermore, a direct writing device (for example, a laser direct imaging device that directly draws images with a laser using CAD data from a computer) can also be used. The lamp light source or laser light source of the direct writing device can have a maximum wavelength in the range of 350 to 450 nm. The exposure amount for image formation varies depending on the film thickness, etc., but is generally 10 to 1000 mJ / cm². 2 Preferably 20-800 mJ / cm² 2 It can be within the range of

[0136] The above-mentioned development method can be the dipping method, shower method, spray method, brush method, etc., and alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines can be used as the developing solution.

[0137] The cured product of the present invention can be obtained by heat curing (for example, 100 to 220°C) after the exposure and development described above (main curing). In this case, it is preferable to irradiate the cured product with active energy rays after heat curing in order to set the average linear expansion coefficient within the range of 70 to 100 ppm / °C. By irradiating with active energy rays again after heat curing, depending on the composition of the curable resin composition, photopolymerizable monomers, etc., can be further cured to adjust the average linear expansion coefficient to a desired level, and as a result, excellent adhesion after curing of the marking ink is also achieved.

[0138] The irradiation of active energy rays after heat curing is preferably 500 to 2000 mJ / cm², depending on the composition of the curable resin composition. 2 It is preferable to perform the procedure with the following exposure level. The apparatus should include a high-pressure mercury lamp (80W / cm²). 3 Examples include three lights.

[0139] The cured product of the present invention is used, for example, to form solder resist, coverlay, or interlayer insulating layer on electronic components such as printed circuit boards. It may also be used to form solder dams on printed circuit boards. Among these uses, it is preferable to use it to form solder resist. With the cured product of the present invention, when the cured product is formed on a printed circuit board as described later, it is easy to apply marking ink to its surface, it exhibits excellent adhesion to the marking ink after curing, and it is possible to form a marker on the surface with excellent visibility of characters and symbols.

[0140] Furthermore, the same method as described above for the method of producing a cured product of the present invention can be used to form a cured product from the resin layer of the photosensitive resin composition or its dry film.

[0141] Furthermore, with the cured product obtained from the photosensitive resin composition of the present invention or the resin layer of its dry film, after exposure and development to form a pattern of the cured product on a substrate, the cured product can be further irradiated with active energy rays and then heat-cured (for example, at 100-220°C), or irradiated with active energy rays after heat curing, or heat-cured alone to perform final finishing curing (main curing), thereby forming a coating (cured film) made of a cured product with excellent properties such as adhesion and hardness.

[0142] [Printed wiring board] The printed circuit board of the present invention has a cured product of the present invention, or a cured product obtained from the photosensitive resin composition of the present invention or its dry film. The method for manufacturing the cured product is as described above. Substrates for forming printed circuit boards include printed circuit boards with circuits pre-formed using copper, flexible printed circuit boards, and materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / nonwoven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, and copper-clad laminates for high-frequency circuits using fluororesin / polyethylene / polyphenylene ether, polyphenylene oxide / cyanate, etc., as well as copper-clad laminates of all grades (FR-4, etc.), metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafers, etc.

[0143] In the printed circuit board of the present invention, after forming a cured film on the substrate as described above, components such as electronic elements are mounted on the substrate by solder reflow. Solder reflow can be performed by conventionally known methods. Solder reflow is generally performed under processing conditions such as 245 to 260°C for 5 to 10 seconds.

[0144] The photosensitive resin composition or its dry film of the present invention is suitably used for manufacturing electronic components such as printed circuit boards, and more preferably for forming permanent coatings. In this case, a cured product is formed using the photosensitive resin composition or its dry film of the present invention by the method described above. When the resin layer of the photosensitive resin composition or its dry film of the present invention is insulating, it is suitably used to form a solder resist, coverlay, or interlayer insulating layer. The photosensitive resin composition of the present invention may also be used to form a solder dam. [Examples]

[0145] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following, "parts" and "%" all refer to mass unless otherwise specified.

[0146] <Synthesis Example 1 (Synthesis of Carboxyl Group-Containing Resin Varnish A1-1)> 220 parts of orthocresol novolac epoxy resin (DIC Corporation, EPICLON N-695, epoxy equivalent: 214, average number of functional groups: 7.6) were placed in a four-necked flask equipped with a stirrer and reflux condenser. 214 parts of carbitol acetate were added and heated until dissolved. Next, 0.1 parts of hydroquinone were added as a polymerization inhibitor, and 2.0 parts of dimethylbenzylamine were added as a reaction catalyst. This mixture was heated to 95-105°C, and 72 parts of acrylic acid were gradually added dropwise, reacting for 16 hours. The reaction product was cooled to 80-90°C, 106 parts of tetrahydrophthalic anhydride were added, reacted for 8 hours, cooled, and then removed. The resulting carboxyl group-containing resin solution had a solid content of 65%, an acid value of 85 mgKOH / g of solids, and a weight-average molecular weight of 10,000. Hereinafter, this resin solution will be referred to as varnish A1-1.

[0147] <Synthesis Example 2 (Synthesis of Carboxyl Group-Containing Resin A1-2)> In a flask equipped with a thermometer, stirrer, dropping funnel, and reflux condenser, 200 parts of phenol novolac type epoxy resin (P-201, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent = 200) and 96.4 parts of carbitol acetate as a solvent were added and heated until dissolved. Subsequently, 0.1 parts of hydroquinone as a polymerization inhibitor and 2.0 parts of triphenylphosphine as a reaction catalyst were added. This mixture was heated to 95-105°C, and 72 parts of acrylic acid were gradually added dropwise, reacting for approximately 16 hours until the acid value was 3.0 mg KOH / g or less. After cooling the reaction product to 80-90°C, 76.1 parts of tetrahydrophthalic anhydride were added, and infrared absorption spectrometry was performed to determine the absorption peak of the acid anhydride (1780 cm⁻¹). -1 The reaction was allowed to proceed for approximately 6 hours until the ) was completely gone. 96.4 parts of Ibsol #150, an aromatic solvent manufactured by Idemitsu Petrochemical Co., Ltd., were added to this reaction solution, diluted, and then removed. The resulting carboxyl group-containing resin solution had a solid content of 65%, an acid value of 78 mgKOH / g, and a weight-average molecular weight of 8,000. Hereinafter, this resin solution will be referred to as varnish A1-2.

[0148] <Synthesis Example 3 (Synthesis of Carboxyl Group-Containing Resin Varnish A2-1)> 371 parts of bisphenol A type epoxy resin (epoxy equivalent 650 g / eq, softening point 81.1°C) with an average degree of polymerization n of 3.3 and 925 parts of epichlorohydrin were dissolved in 462.5 parts of dimethyl sulfoxide. Then, under stirring at 70°C, 52.8 parts of 98.5% sodium hydroxide were added over 100 minutes. After the addition, the reaction was carried out at 70°C for a further 3 hours. After the reaction was complete, 250 parts of water were added and the mixture was washed. After oil-water separation, most of the dimethyl sulfoxide and excess unreacted epichlorohydrin were recovered from the oil layer by distillation under reduced pressure. The remaining by-product salt and reaction product containing dimethyl sulfoxide were dissolved in 750 parts of methyl isobutyl ketone, and 10 parts of 30% sodium hydroxide were added. The mixture was reacted at 70°C for 1 hour. After the reaction was complete, the mixture was washed twice with 200 parts of water. After oil-water separation, methyl isobutyl ketone was recovered from the oil layer by distillation to obtain an epoxy resin with an epoxy equivalent of 287 g / eq and a softening point of 64.2°C. Based on the epoxy equivalent, the obtained epoxy resin had approximately 3.1 of the 3.3 alcoholic hydroxyl groups in the starting material, a bisphenol A type epoxy resin, epoxidized. 310 parts of the obtained epoxy resin and 282 parts of carbitol acetate were placed in a flask, heated to 90°C, stirred, and dissolved. The resulting solution was cooled to 60°C, and 72 parts (1 mole) of acrylic acid, 0.5 parts of methylhydroquinone, and 2 parts of triphenylphosphine were added. The mixture was heated to 100°C and reacted for approximately 60 hours to obtain a reaction product with an acid value of 0.2 mg KOH / g. To this, 140 parts (0.92 moles) of tetrahydrophthalic anhydride were added and heated to 90°C to obtain a carboxyl group-containing resin solution. The carboxyl group-containing resin solution thus obtained had a solid content of 64.0%, an acid value of 100 mg KOH / g of the solid content, and a weight-average molecular weight of 15,000. Hereinafter, this resin solution will be referred to as varnish A2-1.

[0149] <Synthesis Example 4 (Synthesis of Carboxyl Group-Containing Resin Varnish A2-2)> 380 parts of bisphenol F type epoxy resin (epoxy equivalent 950 g / eq, softening point 85°C) with an average degree of polymerization n of 6.2 and 925 parts of epichlorohydrin were dissolved in 462.5 parts of dimethyl sulfoxide. Then, 60.9 parts (1.5 mol) of 98.5% sodium hydroxide were added over 100 minutes at 70°C under stirring. The reaction was continued at 70°C for 3 hours after the addition. After the reaction was complete, 250 parts of water were added and the mixture was washed. After oil-water separation, most of the dimethyl sulfoxide and excess unreacted epichlorohydrin were recovered from the oil layer by distillation under reduced pressure. The remaining by-product salt and reaction product containing dimethyl sulfoxide were dissolved in 750 parts of methyl isobutyl ketone, and 10 parts of 30% sodium hydroxide were added. The mixture was reacted at 70°C for 1 hour. After the reaction was complete, the mixture was washed twice with 200 parts of water. After oil-water separation, methyl isobutyl ketone was recovered from the oil layer by distillation to obtain an epoxy resin with an epoxy equivalent of 310 g / eq and a softening point of 69°C. Based on the epoxy equivalent, the obtained epoxy resin had approximately 5 of the 6.2 alcoholic hydroxyl groups in the aforementioned starting material, bisphenol F-type epoxy resin, epoxidized. 310 parts of the obtained epoxy resin and 282 parts of carbitol acetate were placed in a flask, heated and stirred at 90°C, and dissolved. The resulting solution was cooled to 60°C, and 72 parts (1 mole) of acrylic acid, 0.5 parts of methylhydroquinone, and 2 parts of triphenylphosphine were added. The mixture was heated to 100°C and reacted for approximately 60 hours to obtain a reaction product with an acid value of 0.2 mg KOH / g. To this, 140 parts (0.92 moles) of tetrahydrophthalic anhydride were added and heated to 90°C to obtain a carboxyl group-containing resin solution. The carboxyl group-containing resin solution thus obtained had a solid content of 65.0%, an acid value of 100 mg KOH / g of the solid content, and a weight-average molecular weight of 15,000. Hereafter, this resin solution will be referred to as varnish A2-2.

[0150] <Synthesis Example 5 (Synthesis of Carboxyl Group-Containing Resin Varnish A3-1)> In a 2-liter separable flask equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen inlet tube, 900 parts of diethylene glycol dimethyl ether were added as the solvent and heated to 90°C. After heating, 309.9 parts of methacrylic acid, 116.4 parts of methyl methacrylate, and 109.8 parts of lactone-modified 2-hydroxyethyl methacrylate (Daicel Corporation, Praxel FM1) were added dropwise over 3 hours along with 21.4 parts of the polymerization initiator bis(4-t-butylcyclohexyl) peroxydicarbonate (Nippon Oil & Fats Co., Ltd., Perloyl TCP), and the mixture was aged for a further 6 hours to obtain the product. The reaction was carried out under a nitrogen atmosphere. Next, 363.9 parts of 3,4-epoxycyclohexylmethyl acrylate (Daicel Corporation, Cyclomer A200), 3.6 parts of dimethylbenzylamine as a ring-opening catalyst, and 1.80 parts of hydroquinone monomethyl ether as a polymerization inhibitor were added to the obtained product, and the mixture was heated to 100°C and stirred to carry out the ring-opening addition reaction of epoxy. After 16 hours, a carboxyl group-containing resin was obtained with a solid content of 53.8%, an acid value of 108.9 mgKOH / g of the solid content, and a weight-average molecular weight of 25,000. Hereinafter, this resin solution will be referred to as varnish A3-1.

[0151] <Synthesis Example 6 (Synthesis of Carboxyl Group-Containing Resin A3-2)> In a four-necked flask equipped with a reflux condenser, thermometer, nitrogen-purging glass tube, and stirrer, 42 parts methacrylic acid, 43 parts methyl methacrylate, 35 parts styrene, 100 parts carbitol acetate, 0.5 parts lauryl mercaptan, and 4 parts azobisisobutyronitrile were added. The mixture was heated under a nitrogen stream at 75°C for 5 hours to allow the polymerization reaction to proceed, yielding a carboxyl group-containing resin solution with a solid content of 50%, an acid value of 120 mgKOH / g, and a weight-average molecular weight of 25,000. Hereinafter, this resin solution will be referred to as varnish A3-2.

[0152] <Synthesis Example 7 (Synthesis of Carboxyl Group-Containing Resin Varnish B1)> In an autoclave equipped with a thermometer, a nitrogen introduction device / alkylene oxide introduction device, and a stirring device, 119.4 parts of novolac-type cresol resin (Schoenol CRG951, manufactured by Aica Kogyo Co., Ltd., OH equivalent: 119.4), 1.19 parts of potassium hydroxide, and 119.4 parts of toluene were charged. The system was then heated and the temperature increased while stirring and purging with nitrogen. Next, 63.8 parts of propylene oxide were gradually added dropwise to 125-132°C and 0-4.8 kg / cm³. 2 The reaction was carried out for 16 hours. After cooling to room temperature, 1.56 parts of 89% phosphoric acid were added to the reaction solution and mixed to neutralize the potassium hydroxide, yielding a propylene oxide reaction solution of novolac-type cresol resin with a solid content of 62.1% and a hydroxyl value of 182.2 g / eq. This solution contained an average of 1.08 moles of alkylene oxide added per equivalent of phenolic hydroxyl groups. Next, 293.0 parts of the obtained novolac-type cresol resin alkylene oxide reaction solution, 43.2 parts of acrylic acid, 11.53 g of methanesulfonic acid, 0.18 parts of methylhydroquinone, and 252.9 parts of toluene were charged into a reactor equipped with a stirrer, thermometer, and air blowing tube. Air was blown in at a rate of 10 ml / min, and the mixture was reacted at 110°C for 12 hours while stirring. Of the water produced by the reaction, 12.6 parts of water were distilled off as an azeotropic mixture with toluene. After cooling to room temperature, the resulting reaction solution was neutralized with 35.35 parts of 15% sodium hydroxide aqueous solution, and then washed with water. Subsequently, toluene was removed by distillation in an evaporator while substituting with 118.1 parts of carbitol acetate to obtain a novolac-type acrylate resin solution. Next, 332.5 parts of the obtained novolac-type acrylate resin solution and 1.22 parts of triphenylphosphine were charged into a reactor equipped with a stirrer, thermometer, and air blowing tube. Air was blown in at a rate of 10 ml / min, and while stirring, 60.8 parts of tetrahydrophthalic anhydride were gradually added, and the mixture was reacted at 95-101°C for 6 hours. In this way, a resin solution of a carboxyl group-containing photosensitive resin with a solid content of 71%, an acid value of 88 mgKOH / g of solids, and a weight-average molecular weight of 2,500 was obtained. Hereinafter, this resin solution will be referred to as varnish B1.

[0153] <Synthesis Example 8 (Synthesis of Carboxyl Group-Containing Resin Varnish B2)> 220 parts of cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EOCN-104S, softening point 92°C, epoxy equivalent 220) and 40.2 parts of dimethylolpropionic acid were placed in a flask equipped with a stirrer, condenser, and thermometer. 260 parts of carbitol acetate were added, and the mixture was heated to 90°C until dissolved. The resin solution was then cooled to 60°C, 0.7 parts of triphenylphosphine were added, and the mixture was heated to 100°C and reacted for approximately 32 hours to obtain a resin solution with a solid content of 50% and an epoxy equivalent of 371 g / equivalent. Next, 203 parts of 1,5-dihydroxynaphthalene (hydroxyl equivalent 80 g / equivalent) and 1097 parts of bisphenol A type epoxy resin Epiclon-840 (manufactured by DIC Corporation, epoxy equivalent 180) were charged into a reaction vessel equipped with a gas inlet tube, a stirrer, a condenser, a thermometer, and a dropping funnel for continuous dropwise addition of alkali metal hydroxide aqueous solution. The mixture was dissolved at 120°C under a nitrogen atmosphere with stirring. Subsequently, 0.65 parts of triphenylphosphine were added, the temperature in the flask was raised to 150°C, and the reaction was carried out for approximately 90 minutes while maintaining the temperature at 150°C to obtain an epoxy compound with epoxy equivalent 365 g / equivalent. After that, the temperature in the flask was cooled to below 70°C, 2058 parts of epichlorohydrin and 1690 parts of dimethyl sulfoxide were added, and the temperature was raised to 70°C and maintained therewith with stirring. Subsequently, 244 parts of 48% sodium hydroxide were added dropwise over 90 minutes, followed by a further reaction for 3 hours. After the reaction was complete, most of the excess epichlorohydrin and dimethyl sulfoxide were recovered by vacuum distillation, and the reaction product, including the by-product salt and dimethyl sulfoxide, was dissolved in methyl isobutyl ketone and washed with water. After separating the organic solvent layer from the aqueous layer, methyl isobutyl ketone was removed from the organic solvent layer by vacuum distillation to obtain a polynuclear epoxy compound with an epoxy equivalent of 275 g / equivalent (epoxidation rate of alcoholic hydroxyl groups was approximately 48%). Next, 371 parts of the resin solution prepared as described above and 137.5 parts of the polynuclear epoxy compound were placed in a flask equipped with a stirrer, condenser, and thermometer. 137 parts of carbitol acetate were added and heated until dissolved. 0.46 parts of methyl hydroquinone and 1.38 parts of triphenylphosphine were added, and the mixture was heated to 95-105°C. 72 parts of acrylic acid were gradually added dropwise, and the mixture was reacted for 16 hours. The reaction product was cooled to 80-90°C, 146 parts of tetrahydrophthalic anhydride were added, and the mixture was reacted for 8 hours. The reaction was tracked by measuring the oxidation and total oxidation of the reaction solution by potentiometric titration, and the reaction rate was considered to have terminated when the reaction rate was 95% or higher. In this way, a resin solution containing carboxyl groups was obtained, with a solid content of 62%, an acid value of 102 mgKOH / g of the solid content, and a weight-average molecular weight of 10,000. Hereinafter, this resin solution will be referred to as varnish B2.

[0154] <Synthesis Example 9 (Synthesis of Carboxyl Group-Containing Resin Varnish B3)> 650 parts of carbitol acetate were mixed with 1070 parts of orthocresol novolac epoxy resin (DIC Corporation, EPICLON N-695, softening point 95°C, epoxy equivalent 214, average number of functional groups 7.6), 360 parts of acrylic acid, and 1.5 parts of hydroquinone. The mixture was heated to 100°C and stirred until uniformly dissolved. Next, 4.3 parts of triphenylphosphine were added and the mixture was heated to 110°C for 2 hours. After that, an additional 1.6 parts of triphenylphosphine were added, and the temperature was raised to 120°C for a further 12 hours of reaction. To the obtained reaction solution, 525 parts of aromatic hydrocarbon (T-Sol 150, manufactured by Standard Petroleum Co., Ltd. Osaka Sales Office) and 608 parts (4.0 mol) of tetrahydrophthalic anhydride were charged, and the reaction was carried out at 110°C for 4 hours. Furthermore, 142.0 g of glycidyl methacrylate was charged to the obtained reaction solution, and the reaction was carried out at 115°C for 4 hours. In this way, a resin solution containing carboxyl groups was obtained with a solid content of 65%, an acid value of 77 mgKOH / g of the solid content, and a weight-average molecular weight of 11,000 to 12,000. Hereafter, this resin solution will be referred to as varnish B3.

[0155] <Preparation of curable resin composition> Each curable resin composition listed in Table 1 below was obtained by blending the components listed in the table and mixing them at room temperature using a three-roll mill. The values ​​in the table represent parts by mass. Furthermore, the amounts (values) for each component indicate the amount of solids blended (the amount of organic solvent (carbitol acetate) listed in the table is the actual amount blended).

[0156] The components *1 to *18 in Table 1 below are as follows: *1: Dipentaerythritol penta and hexaacrylate, photopolymerizable monomer (DPHA, manufactured by Kyoeisha Chemical Co., Ltd.) *2: Urethane acrylate oligomer (CN9178, manufactured by Arkema (Sartomer)) *3: Cresol novolac type epoxy resin (RN-695, manufactured by DIC Corporation) *4: Triepoxy resin having an isocyanuric ring (TEPIC-S, manufactured by Nissan Chemical Corporation) *5: Bisphenol A type epoxy resin (jER 828, manufactured by Mitsubishi Chemical Corporation) *6: Dicyclopentadiene skeleton-containing polyfunctional solid epoxy resin (HP-7200, manufactured by DIC Corporation) *7: Biphenyl aralkyl epoxy resin (YX-4000, manufactured by Nippon Kayaku Co., Ltd.) *8: Biphenyl aralkyl epoxy resin (NC3000H, manufactured by Mitsubishi Chemical Corporation) *9: α-aminoacetophenone-based photopolymerization initiator (Omnirad 907, manufactured by IGM Resins) *10: Acyl phosphine oxide photopolymerization initiator (Omnirad 819, manufactured by IGM Resins) *11: α-aminoacetophenone-based photopolymerization initiator (Omnirad 369, manufactured by IGM Resins) *12: Titanocene-based photopolymerization initiator (JMT-784, manufactured by Yueyang Kimoutain Sci-tech Co.Ltd.) *13: Amorphous silica (FS-3DC, manufactured by Denka Co., Ltd., D50 = 2.9 μm) *14: Amorphous silica (HS-311, manufactured by Nippon Steel Chemical & Material Co., Ltd., D50 = 2.2 μm) *15: Talc (LMP-100, manufactured by Fuji Talc Industry Co., Ltd.) *16: Barium sulfate (B-100, manufactured by Sakai Chemical Industry Co., Ltd.) *17: 2,4-Diethylthioxanthone (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) *18:2-Isopropylthioxanthone (KAYACURE ITX, manufactured by Nippon Kayaku Co., Ltd.) *19: Melamine (manufactured by Nissan Chemical Corporation, D50 = 0.5 μm)

[0157] <Preparation of hardened material> The curable resin compositions of the examples and comparative examples were screen printed onto copper-clad laminates for printed circuit boards (FR-4, 1.6 mm thick, 150 x 95 mm in size) to form a solid coating with a dry film thickness of 20 μm, and then dried at 80°C for 30 minutes to form the coating. Next, the coating film was exposed to light in a pattern that left the coating film covering the entire surface, and then developed in a 1 wt% Na2CO3 solution at 30°C for 60 seconds. The optimal exposure amount was determined when, after drying, exposure was performed using a metal halide lamp-equipped exposure apparatus via a step tablet (Kodak No. 2), and development (30°C, 0.2 MPa, 30°C, 1 wt% Na2CO3 solution) for 60 seconds, resulting in a pattern of 7 steps remaining on the step tablet. Furthermore, after exposure and development, the film was cured at 150°C for 30 minutes. After curing, Examples 1 and 2 and Comparative Example 2 were further treated with a high-pressure mercury lamp (80 W / cm²). 3 3 lamps 1000 mJ / cm 2 The surface of the coating film was irradiated using () to obtain a test substrate 1 with a cured product (cured film) formed on it.

[0158] <Evaluation of physical properties of cured materials> The average linear thermal expansion coefficient and glass transition temperature (Tg) of the obtained cured material at 0 to 180°C were measured as follows. The cured material obtained as described above was cut into 3 mm wide and 30 mm long specimens to form test pieces, and the coefficient of thermal expansion in tensile mode was measured using a thermomechanical analyzer (TMA / SS6000, manufactured by Seiko Instruments Inc.). The maximum tensile load was 50 N / m, the span (distance between chucks) was 10 mm, and the heating rate was 10 °C / min. The test pieces were mounted in the thermomechanical analyzer, heated from 30 °C to 200 °C, left for 10 minutes, then cooled to -30 °C at a cooling rate of -10 °C / min, and measurements were taken from -30 °C to 250 °C at a heating rate of 10 °C / min. The measured values ​​at 0 °C and 180 °C were read, and the average linear expansion coefficient (α) was calculated using the following formula. α=(1 / LS)×[{L(180)-L(0)} / (T(180)-T(0)] (Note that in the formula, LS: Length of the test specimen (cured material) before measurement (measured value) L(0): Change in length of the test specimen (cured material) at 0°C (measured value) L(180): Change in length of the test specimen (cured material) at 180°C (measured value) T(0):0(℃) T(180): 180(℃) (That is the case.) Furthermore, from the obtained TMA curve, a straight line A passing through the points 0°C and 30°C, and a straight line B passing through the points 150°C and 180°C were drawn, and the temperature at the point where straight line A and straight line B intersect (extrapolation point) was defined as the Tg of the cured product of the present invention. The measurement results are shown in Table 1 below.

[0159] [Table 1]

[0160] <Marking Evaluation> (1) Printability On the cured coating surface of the test substrate obtained as described above, a 10 x 20 mm rectangle was printed using marking ink (PMR-6000 W30, manufactured by Taiyo Ink Mfg. Co., Ltd.) so that the cured film thickness would be 20 μm. This was dried at 80°C for 30 minutes to form a marker. The printing condition of the marker area was visually inspected, and the marking printability was evaluated according to the evaluation criteria below. ○: No smudging or blurring is observed. ×: Blurring or smudging is visible. The evaluation results are shown in Table 2 below.

[0161] (2) Adhesion On the cured coating surface of the test substrate obtained as described above, a 10 x 20 mm rectangle was printed using marking ink (PMR-6000 W30, manufactured by Taiyo Ink Mfg. Co., Ltd.) so that the cured film thickness would be 20 μm. After drying at 80°C for 30 minutes, the printed area was exposed to light in a pattern that left approximately 10-20 μm characters and symbols, and this was developed at 30°C with 1 wt% Na2CO3 for 60 seconds. The optimal exposure amount was determined when, after drying, exposure was performed using a metal halide lamp-equipped exposure device via a step tablet (Kodak No. 2), and development (30°C, 0.2 MPa, 30°C, 1 wt% Na2CO3 solution) for 60 seconds, resulting in a pattern of 8 steps remaining on the step tablet. Furthermore, the developed coating was washed with 10°C water for 60 seconds, and then cured at 180°C for 45 minutes to form a marker. Next, adhesive tape was applied to the marker area, and a peeling test was conducted. The evaluation criteria were as follows: ◎: No peeling ○: Some slight peeling is observed in some areas. ×: Complete peeling is observed. The evaluation results are shown in Table 2 below.

[0162] (3) Visibility of the marker For the evaluation samples that underwent the adhesion evaluation described in (2) above, the legibility of the letters and symbols on the marker portion was visually confirmed. The evaluation criteria for the visibility of the marker were as follows. ◎: All characters and symbols are legible. ○: Some characters and symbols are difficult to read. ×: The text and symbols are illegible throughout. The evaluation results are shown in Table 2 below.

[0163] [Table 2]

[0164] As is clear from Table 1, in cured products (Examples 1-3) where the average coefficient of linear expansion when the temperature changes from 0°C to 180°C is in the range of 70-100 ppm / °C, it is possible to form markers that have good printability of marking ink, excellent adhesion to marking ink, and excellent visibility of letters and symbols. In contrast, when the average coefficient of linear expansion is less than 70 ppm / °C or exceeds 100 ppm / °C (Comparative Examples 2 and 3), it can be seen that the printability of the marking ink is not good, and the adhesion to the marking ink is also insufficient. Furthermore, even when the average coefficient of linear expansion when the temperature changes from 0°C to 180°C is within the range of 70 to 100 ppm / °C, cured products formed using curable resin compositions that do not contain amorphous silica exhibit poor printability with marking inks, and also have insufficient adhesion to marking inks, similar to the other comparative examples.

[0165] <Preparation of photosensitive resin composition> Each of the components listed in Table 3 below was blended and mixed at room temperature using a three-roll mill to obtain each of the photosensitive resin compositions listed in the table. The values ​​in the table represent parts by mass. The amounts of each carboxyl group-containing resin listed in the table represent the amounts used in the varnish obtained as described above. Components *1 to *19 in Table 3 below are as described above.

[0166] <Evaluation of Photosensitive Resin Composition> (1) Evaluation of Reattachment of Development Residue This evaluation was conducted as an item for evaluating suppression of plating defects. Specifically, each photosensitive resin composition obtained as described above was applied to a substrate with a comb-shaped L / S = 100 μm / 100 μm pattern having a 0.5 m × 0.5 m × 1.6 mm Pad portion polished with a buff, and a coating film was formed by double-sided screen printing so that the film thickness after development was 20 μm. Next, after holding the substrate on which the coating film was formed for 10 minutes, it was dried in a hot air circulation drying oven at 80°C for 40 minutes. After leaving the substrate with the dried coating film at room temperature for 30 minutes, 100 sheets were developed using a developing machine (manufactured by Tokyo Chemical Industry Co., Ltd., solder resist developing apparatus (150L tank)) containing 1% Na2CO3 aqueous solution (liquid temperature 30°C), and the number of reattachments of development residues was visually confirmed. The evaluation criteria were as follows. ○: There were 0 reattachments. △: There were 1 to 9 reattachments. ×: There were 10 or more reattachments. The evaluation results were as shown in Table 3 below.

[0167] (2) PCBT (Pressure Cooker Bias Test) This evaluation was conducted as an item for evaluating the characteristics (insulation reliability) required for solder resist. Specifically, each photosensitive resin composition was applied to a substrate with a comb-shaped L / S = 100 μm / 100 μm pattern having a Pad portion, and a coating film was formed by double-sided screen printing so that the film thickness after development was 20 μm. Next, the substrate on which the coating film was formed was dried in a hot air circulation drying oven at 80°C for 40 minutes. After leaving the substrate with the dried coating film at room temperature for 30 minutes, it was exposed at an exposure amount of 400 mJ / cm 2 and developed for 60 seconds using a developing machine (manufactured by Tokyo Chemical Industry Co., Ltd., solder resist developing apparatus (150L tank)) containing 1% Na2CO3 aqueous solution (liquid temperature 30°C). Subsequently, a post-cure treatment was performed at 150°C for 60 minutes to cure the coating film, and a substrate with a cured film (hereinafter referred to as "test substrate") was produced. The insulation reliability of the obtained test board was continuously measured in the chamber using an insulation degradation evaluation tester (MIG-8600B manufactured by IMV Corporation) at 121°C, 97% humidity, and an applied voltage of 30V, and the resistance value was 10 6 The time it took for the resistance to fall below Ω and for insulation to be lost was measured. The evaluation criteria were as follows: ◎: 150 hours or more ○:100~149 hours △:50~99 hours ×: 49 hours or less The evaluation results are shown in Table 3 below.

[0168] (3) Plating evaluation The following evaluations were conducted to assess the suppression of plating defects. Specifically, the above test substrates were degreased by immersing them in an acidic degreasing solution at 30°C (a 20 vol% aqueous solution of Metex L-5B, manufactured by MacDermid Japan Co., Ltd.) for 3 minutes, and then rinsed with running water for 3 minutes. Next, the test substrate was immersed in a 14.3 wt% ammonium persulfate aqueous solution at room temperature for 3 minutes to perform soft etching, and then rinsed with running water for 3 minutes. After immersing the test substrate in a 10 vol% sulfuric acid aqueous solution at room temperature for 1 minute, it was rinsed with running water for 30 seconds to 1 minute. Next, the test substrate was immersed in a catalyst solution at 30°C (a 10 vol% aqueous solution of Metal Plate Activator 350, manufactured by Meltex Co., Ltd.) for 7 minutes to apply the catalyst, and then rinsed with running water for 3 minutes. The catalyst-treated test substrates were immersed in a nickel plating solution (20 vol% aqueous solution of Melplate Ni-865M, manufactured by Meltex Co., Ltd., pH 4.6) at 85°C for 30 minutes to perform electroless nickel plating. After immersing the test substrates in a 10 vol% sulfuric acid aqueous solution at room temperature for 1 minute, they were rinsed with running water for 30 seconds to 1 minute. Next, the test substrate was immersed in a 95°C gold plating solution (aqueous solution of 15 vol% Aurolectroles UP and 3 vol% potassium gold cyanide, pH 6, manufactured by Meltex Co., Ltd.) for 30 minutes to perform electroless gold plating to a thickness of 5 μm for Ni and 0.05 μm for Au. After that, it was rinsed with running water for 3 minutes and then rinsed again with hot water at 60°C for 3 minutes. After thorough rinsing with water, the water was drained well and the substrate was dried to obtain the electroless gold plated test substrate.

[0169] The pad portions of the test substrates that underwent electroless gold plating as described above were visually inspected to confirm whether plating had been applied, and the presence or absence of plating was evaluated according to the following criteria. ○: No instances of unplated areas were observed. △: One area where plating was not applied was observed. ×: Numerous areas where plating was not applied were observed. The evaluation results are shown in Table 3 below.

[0170] Furthermore, the following evaluations were conducted to assess the suppression of contamination in the plating solution. Specifically, the pad portion of the test substrate was visually inspected for any abnormalities on the plated surface, and the presence or absence of abnormalities on the plated surface was evaluated according to the following criteria. ○: 0 abnormal locations △: One abnormal area ×: Numerous abnormalities The evaluation results are shown in Table 3 below.

[0171] [Table 3]

[0172] As is clear from Table 3, the photosensitive resin compositions (Examples 4-8) obtained by combining three specific types of carboxyl group-containing resins in specific proportions can be seen to suppress contamination of the plating solution and the occurrence of plating defects while satisfying the properties required for solder resists, such as insulation reliability. On the other hand, in a photosensitive resin composition (Comparative Example 4) that uses only a carboxyl group-containing resin having a novolac skeleton as the carboxyl group-containing resin, contamination of the plating solution and the occurrence of plating defects can be suppressed, but the properties required for solder resist, such as insulation reliability, are insufficient. Furthermore, in the photosensitive resin composition using two types of carboxyl group-containing resins, namely a carboxyl group-containing resin having a novolac skeleton and a carboxyl group-containing resin having a bisphenol skeleton (Comparative Example 5), and in the photosensitive resin composition using two types of carboxyl group-containing resins, namely a carboxyl group-containing resin having a bisphenol skeleton and an unsaturated basic acid copolymer type carboxyl group-containing resin (Comparative Example 6), abnormalities appear to occur on the plated surface and contamination of the plating solution. Furthermore, in a photosensitive resin composition (Comparative Example 7) that uses two types of carboxyl group-containing resins in combination—a carboxyl group-containing resin having a novolac skeleton and an unsaturated basic acid copolymer type carboxyl group-containing resin—defects such as incomplete plating occurred due to the influence of residue in the developing solution. Furthermore, even when three specific types of carboxyl group-containing resins are combined, the photosensitive resin composition (Comparative Example 8) in which each component is outside the predetermined ratio range satisfies the properties required for solder resist, such as insulation reliability, but defects such as non-adhesion of plating occur due to the influence of residue in the developing solution, and abnormalities occur on the plated surface, resulting in contamination of the plating solution.

Claims

1. A cured product comprising a curable resin composition containing a curable resin and an inorganic filler, The inorganic filler contains amorphous silica, A cured product characterized in that the average coefficient of linear expansion of the cured product when the temperature is changed from 0°C to 180°C is 70 to 100 ppm / °C.

2. The cured product according to claim 1, wherein the glass transition temperature (Tg) is in the range of 100 to 120°C.

3. The cured product according to claim 1, wherein the average coefficient of linear expansion of the cured product when the temperature is changed from 0°C to 180°C is 70 to 85 ppm / °C.

4. The cured product according to claim 1, wherein the curable resin includes a thermosetting resin and a photocurable resin.

5. The cured product according to claim 1, wherein the amorphous silica is contained in an amount of 2 to 30% by mass relative to the entire curable resin composition on a solid content basis.

6. A photosensitive resin composition comprising (A) a carboxyl group-containing resin, (B) a photopolymerizable monomer, and (C) a thermosetting component, (A) Carboxyl group-containing resin, (A1) A carboxyl group-containing resin having a novolac skeleton, (A2) A carboxyl group-containing resin having a bisphenol skeleton, (A3) Unsaturated basic acid copolymer type carboxyl group-containing resin, Includes, The total amount of the carboxyl group-containing resin (A1) and the carboxyl group-containing resin (A2) is 60 to 80% by mass relative to the total amount of the carboxyl group-containing resin (A). A photosensitive resin composition characterized in that the amount of the carboxyl group-containing resin (A3) is 40 to 20% by mass relative to the total amount of the carboxyl group-containing resin (A).

7. The photosensitive resin composition according to claim 6, wherein the carboxyl group-containing resin (A3) is a reaction product of an unsaturated basic acid copolymer resin and an alicyclic epoxy group-containing unsaturated compound.

8. The photosensitive resin composition according to claim 6, wherein the amount of the carboxyl group-containing resin (A1) is 10 to 60% by mass relative to the total amount of the carboxyl group-containing resin (A).

9. The photosensitive resin composition according to claim 6, wherein the amount of the carboxyl group-containing resin (A2) is 20 to 50% by mass relative to the total amount of the carboxyl group-containing resin (A).

10. The photosensitive resin composition according to claim 6, wherein the (C) thermosetting component comprises an epoxy resin having an isocyanuric ring.

11. (D) The photosensitive resin composition according to claim 6, further comprising an inorganic filler.

12. The photosensitive resin composition according to claim 11, wherein the (D) inorganic filler contains fused silica.

13. A dry film having a resin layer obtained by applying and drying the photosensitive resin composition according to claim 6 onto a first film.

14. A cured product obtained by curing the resin layer of the photosensitive resin composition described in claim 6 or the dry film described in claim 13.

15. A cured product according to claim 1 or 14, used in solder resist.

16. A printed circuit board comprising a cured material according to claim 1 or claim 14 on a substrate.

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