Alkaline developing curable resin composition, dry film, cured product and electronic component

Abstract

Provided are an alkaline developing curable resin composition, a dry film having a resin layer formed from the resin composition, a cured product formed from the resin composition, and an electronic component having the cured product. The alkaline developing curable resin composition and the cured product thereof exhibit excellent acid resistance, electroless gold plating resistance, electrolytic gold plating resistance and chemical tin plating resistance, and are less prone to coarsening. The alkaline developing curable resin composition comprises (A) a carboxyl-containing resin, (B) a photopolymerization initiator, (C) an antioxidant, (D) barium sulfate, and (E) talc, wherein the antioxidant (C) has a relative molecular weight of 600 g / mol or more and 1200 g / mol or less and a melting point of 100°C or higher and 130°C or lower, and the barium sulfate (D) is barium sulfate which is subjected to surface treatment with an amine-based substance and has an average particle size of 0.5 um or less.

Description

Alkaline developer-curable resin compositions, dry films, cured products, and electronic components Technical Field

[0001] The present invention relates to an alkaline developing type curable resin composition, a dry film having a resin layer formed from the resin composition, a cured product formed from the resin composition, and an electronic component having the cured product. Background Technology

[0002] Currently, for most printed circuit board solder resists, liquid-developable solder resist inks are used from the perspective of high precision and high density. These inks form an image through development after ultraviolet irradiation and are then cured by heat and light irradiation (primary curing). Additionally, due to environmental concerns, alkaline-developable liquid solder resist inks that use a dilute alkaline aqueous solution as the developer have become the mainstream.

[0003] As for such alkaline developable curable resin compositions (solder resist inks), the prior art has explored many avenues: for example, Patent Document 1 discloses a dilute alkaline developable photosensitive imaging solder resist ink, which uses photosensitive resin modified acrylate photosensitive oligomer as the main resin, and the printed circuit board made from it has high temperature resistance, good gloss, and excellent circuit appearance; Patent Document 2 discloses a two-component photosensitive resin composition containing carboxyl resin and epoxy resin respectively, which has high heat resistance, adhesion reduction prevention, and thermal cycling resistance; Patent Document 3 provides an alkaline developable thermosetting resin composition that can form a patterned layer even with high filler inorganic filler, and has excellent thermal cycling characteristics.

[0004] However, during the fabrication of printed circuit boards, the solder resist composition used to form the film undergoes high-temperature processes such as reflow soldering at around 250°C, tin spraying at around 288°C, or electroless nickel immersion gold (ENIG) plating, which can lead to thermal oxidation of organic compounds in the cured coating. After these high-temperature processes, the thermal oxidation of organic compounds may damage the coating structure, resulting in a decrease or loss of solder resist functionality.

[0005] To address this issue, conventional alkaline developable solder resist inks typically employ acrylic resins and epoxy resins (e.g., Patent Documents 1 and 2), filler powders (e.g., Patent Document 3), etc., under photothermal reaction to ensure the chemical gold plating resistance of the cured coating. This generally meets the requirements for chemical gold plating resistance of 0.03μm (Au) and 0.1μm (Ni), but cannot meet the requirements for electrolytic gold plating, let alone the requirements for chemical tin plating resistance.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: CN1390898A

[0009] Patent Document 2: CN110320752A

[0010] Patent Document 3: CN104334604A Summary of the Invention

[0011] The problem the invention aims to solve

[0012] Under the thermal oxidation of organic compounds caused by the aforementioned high-temperature process, the chemical bonds of the organic compounds break, generating reactive free radicals and hydroperoxides. Hydroperoxides further form hydrocarbon radicals and hydroxyl radicals, which can initiate a series of free radical chain reactions, leading to changes in the structure and properties of the organic compounds. A common method to solve this problem is to add antioxidants to the coating.

[0013] However, the inventors of this invention have discovered through research that if the relative molecular mass, melting point, or other properties of the antioxidant used are too low or too high, it will affect the acid resistance, electroplating gold properties, and tin resistance of the cured resin composition.

[0014] On the other hand, the inventors of the present invention have also discovered that when inorganic fillers are added to the above-mentioned resin composition, barium sulfate and talc can affect the above-mentioned properties of the cured resin composition.

[0015] To address the aforementioned problems, the present invention aims to provide an alkaline developable curable resin composition and its cured product that exhibit excellent resistance to acid, chemical gold plating, electrolytic gold plating, and tin plating. It also provides a dry film having a resin layer formed from the resin composition and an electronic component having the cured product.

[0016] Solution for solving the problem

[0017] The inventors conducted in-depth research and found that by combining at least a carboxyl-containing resin, a photopolymerization initiator, a specific antioxidant, and specific barium sulfate and talc in an alkaline developing and curing resin composition, the acid resistance, chemical gold plating resistance, electrolytic gold plating resistance, and tin plating resistance of the cured product can be improved, and the product is less prone to roughening, thereby solving all the above problems, thus completing the present invention.

[0018] That is, the present invention is as follows.

[0019] [1]. This invention provides an alkaline developing and curing resin composition, comprising (A) a carboxyl-containing resin, (B) a photopolymerization initiator, (C) an antioxidant, (D) barium sulfate, and (E) talc.

[0020] The antioxidant (C) has a relative molecular weight of 600 g / mol or higher and 1200 g / mol or lower, and a melting point of 100°C or higher and 130°C or lower.

[0021] The (D) barium sulfate is barium sulfate with an average particle size of less than 0.5 μm that has been surface-treated with amine substances.

[0022] [2]. The alkaline developing type curable resin composition according to [1], wherein the content of barium sulfate (D) is 100 parts by mass or more and 250 parts by mass or less relative to 100 parts by mass of the carboxyl-containing resin (A) based on solid content.

[0023] [3]. The alkaline developing type curable resin composition according to [1] or [2], wherein the mass ratio of the (D) barium sulfate to the (C) antioxidant is 100 parts: 0.5 to 3.5 parts.

[0024] [4]. The alkaline developing type curable resin composition according to [1] or [2], wherein the mass ratio of (D) barium sulfate to (E) talc is 100 parts: 2 to 7 parts.

[0025] [5]. The alkaline developing type curable resin composition according to [1] or [2], wherein the antioxidant (C) is a hindered phenolic antioxidant.

[0026] [6]. The alkaline developing type curable resin composition according to [1] or [2], wherein the (D) barium sulfate is barium sulfate that has been surface-treated with triethanolamine.

[0027] [7]. The present invention provides a dry film having a resin layer on a carrier film, said resin layer being formed from any one of the alkaline developing type curable resin compositions described in [1] to [6].

[0028] [8]. The present invention also provides a cured product obtained by curing the alkaline developing type curable resin composition described in any one of [1] to [6].

[0029] [9]. The present invention also provides a cured product obtained by curing the resin layer of the dry film described in [7].

[0030]

[0010] . The present invention also provides an electronic component having the cured material described in [8] or [9].

[0031] The effects of the invention

[0032] According to the present invention, an alkaline developer-curable resin composition, a dry film having a resin layer formed from the resin composition, a cured product formed from the resin composition, and an electronic component having the cured product can be provided. The alkaline developer-curable resin composition and its cured product exhibit excellent acid resistance, chemical gold plating resistance, electrolytic gold plating resistance, and tin plating resistance, and are less prone to coarsening. Attached Figure Description

[0033] Figure 1 shows a photograph of the cured coating after tape removal, which was rated "×" for chemical gold plating resistance in the comparative example.

[0034] Figure 2 shows a photograph of the cured coating after tape peeling, which was rated as "×" for chemical gold plating resistance in the comparative example.

[0035] Figure 3 shows a photograph of the cured coating after tape peeling, which was rated "×" for chemical gold plating resistance in the comparative example.

[0036] Figure 4 shows a photograph of the cured coating after tape removal, which was rated "△" (significant whitening was confirmed) in the comparative example.

[0037] Figure 5 shows a photograph of the cured coating after tape removal for the comparative example where the electroplating performance was rated as "×" (significant copper leakage was confirmed).

[0038] Figure 6 shows a photograph of the cured coating after tape removal for the comparative example whose electroplating performance was rated as "×" (significant copper leakage was confirmed).

[0039] Figure 7 shows a photograph of the cured coating after tape removal for the comparative example where the electroplating performance was rated as "×" (significant copper leakage was confirmed).

[0040] Figure 8 shows a photograph of the cured coating after tape peeling, which was rated as “○” for electroplating performance in the embodiment.

[0041] Figure 9 shows a photograph of the cured coating after tape peeling, which was rated as “○” for electroplating performance in the embodiment. Detailed Implementation

[0042] This invention provides an alkaline, developer-curable resin composition comprising (A) a carboxyl-containing resin, (B) a photopolymerization initiator, (C) an antioxidant, (D) barium sulfate, and (E) talc.

[0043] The antioxidant (C) has a relative molecular weight of 600 g / mol or higher and 1200 g / mol or lower, and a melting point of 100°C or higher and 130°C or lower.

[0044] The (D) barium sulfate is barium sulfate with an average particle size of less than 0.5 μm that has been surface-treated with amine substances.

[0045] (A) Carboxyl-containing resin

[0046] The carboxyl-containing resin (A) in the alkaline developable curable resin composition of the present invention can be any known resin containing carboxyl groups in its molecule that imparts alkaline developability. From the perspective of excellent tin resistance, the carboxyl-containing resin (A) is preferably a carboxyl-containing resin having olefinic unsaturated double bonds in its molecule, and more preferably a carboxyl-containing resin having a phenolic varnish backbone.

[0047] The following shows a specific example of (A) carboxyl-containing resin.

[0048] (1) A carboxyl-containing resin obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with compounds containing unsaturated groups such as styrene, α-methylstyrene, lower alkyl esters of (meth)acrylic acid, and isobutylene.

[0049] (2) A carboxyl-containing polyurethane resin obtained by the addition polymerization reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with carboxyl-containing diol compounds such as dimethylolpropionic acid and dimethylolbutyric acid, as well as diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A epoxy alkyl adduct diols, and compounds with phenolic hydroxyl and alcoholic hydroxyl groups.

[0050] (3) Polyurethane resin is obtained by addition polymerization of diisocyanate compounds such as aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate with diol compounds such as polycarbonate polyol, polyether polyol, polyester polyol, polyolefin polyol, acrylic polyol, bisphenol A epoxy alkyl adduct diol, and compounds with phenolic hydroxyl and alcoholic hydroxyl groups. The polyurethane resin is then reacted with acid anhydride to obtain a polyurethane resin with carboxyl groups at the end.

[0051] (4) A photosensitive carboxyl-containing polyurethane resin obtained by addition polymerization of diisocyanate with 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, biphenol type epoxy resin, etc., meth)acrylate or its partial anhydride modified form, carboxyl-containing diol compound, and diol compound.

[0052] (5) A carboxyl-containing polyurethane resin obtained by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups, such as (meth)acrylic acid hydroxyalkyl ester, to the resin synthesis of (2) or (4) above for terminal (meth)acrylation.

[0053] (6) A carboxyl-containing polyurethane resin is obtained by adding equimolar reactants of isophorone diisocyanate and pentaerythritol triacrylate to the resin synthesis of (2) or (4) above and performing terminal (meth)acrylation of compounds having one isocyanate group and one or more (meth)acryloyl groups.

[0054] (7) A carboxyl-containing resin is obtained by reacting a difunctional epoxy resin or a polyfunctional epoxy resin with (meth)acrylic acid to add phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, or other dicarboxylic anhydride to the hydroxyl groups present in the side chain.

[0055] (8) The multifunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of the difunctional epoxy resin with epichlorohydrin is reacted with (meth)acrylic acid, and the generated hydroxyl groups are added to the dicarboxylic acid anhydride to obtain a carboxyl-containing resin.

[0056] (9) A polyfunctional oxobutane resin is reacted with a dicarboxylic acid, and the resulting primary hydroxyl group is added to a dicarboxylic acid anhydride to obtain a carboxyl-containing polyester resin.

[0057] (10) A carboxyl-containing resin is obtained by reacting a compound with multiple phenolic hydroxyl groups in one molecule with ethylene oxide, propylene oxide and other epoxides, reacting the reaction product with a monocarboxylic acid containing unsaturated groups, and reacting the reaction product with a polyacid anhydride.

[0058] (11) A carboxyl-containing resin is obtained by reacting a compound with multiple phenolic hydroxyl groups in one molecule with cyclic carbonates such as ethylene carbonate and propylene carbonate, reacting the reaction product with a monocarboxylic acid containing unsaturated groups, and reacting the resulting reaction product with a polyacid anhydride.

[0059] (12) A carboxyl-containing resin is 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-hydroxyphenylethanol, with a monocarboxylic acid containing unsaturated groups, such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl group of the resulting reaction product with polyacid anhydrides such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and adipic anhydride.

[0060] (13) A carboxyl-containing resin having at least one of an amide structure and an imide structure.

[0061] (14) A carboxyl-containing resin obtained by further adding (meth)acrylate, α-methylglycidyl (meth)acrylate, methyl 3,4-epoxycyclohexyl methacrylate, etc., to any of the carboxyl-containing resins mentioned in (1) to (13) above.

[0062] As particularly preferred substances in these examples, cresol or phenolic varnishes are preferred, for example, the carboxyl-containing resins of (7), (10), and (14).

[0063] It should be noted that in this specification, (meth)acrylate refers to the general term acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions.

[0064] As described above, (A) a carboxyl-containing resin has multiple carboxyl groups on the side chains of the main polymer chain (polymer backbone), thus enabling development using a dilute alkaline aqueous solution. Furthermore, the acid value of this carboxyl-containing resin is suitable in the range of 40–200 mg KOH / g. When the acid value of the carboxyl-containing resin is within this range, the resulting cured coating exhibits excellent adhesion, alkaline development becomes easier, dissolution of exposed areas caused by the developer is suppressed, lines are not excessively fine, and the depiction of normal resist patterns becomes easier. The acid value of the carboxyl-containing resin is more preferably in the range of 45–120 mg KOH / g.

[0065] Furthermore, the weight-average molecular weight of this carboxyl-containing resin varies depending on the resin skeleton, and is typically preferably in the range of 2,000 to 150,000, more preferably in the range of 5,000 to 100,000. Within this range, the non-stick properties are good, the cured film after exposure exhibits good moisture resistance, and film reduction is less likely to occur during development. Simultaneously, resolution is improved, developability is good, and storage stability becomes better.

[0066] (A) The amount of carboxyl-containing resin in the formulation, based on the solid content of the alkaline developer-curable resin composition, should be 20 to 80% by mass. When it is 20% or more and 80% or less by mass, the film strength is good while maintaining the ink characteristics, and the viscosity of the composition can be reduced, and the coatability is also excellent. More preferably, the formulation amount is in the range of 20 to 40% by mass.

[0067] The carboxyl-containing resin in (A) above may optionally include known resins, not limited to those listed above.

[0068] (B) Photopolymerization initiator

[0069] As for the photopolymerization initiator used in the alkaline developer-curable resin composition of the present invention, there are no particular limitations as long as it is a photopolymerization initiator commonly used in alkaline developer-curable resin compositions.

[0070] As photopolymerization initiators, known substances can be used, including: benzoin, benzoin methyl ether, benzoin ethyl ether, and other benzoin and its alkyl ethers; acetophenones, such as 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, and 4-(1-tert-butyldioxy-1-methylethyl)acetophenone; anthraquinones, such as 2-methylanthraquinone, 2-pentylanthraquinone, 2-tert-butylanthraquinone, and 1-chloroanthraquinone; and isopropylthioxanthone. Thioxanones such as 2,4-dimethylthioxanone, 2,4-diisopropylthioxanone, and 2-chlorothioxanone; ketals such as acetophenone dimethyl ketal and benzoyl dimethyl ketal; benzophenones such as 4,4'-bis(diethylamino)benzophenone, 4-(1-tert-butyldioxy-1-methylethyl)benzophenone, and 3,3',4,4'-tetra(tert-butyldioxycarbonyl)benzophenone; and xanthones, etc.

[0071] Alternatively, as a photopolymerization initiator, one or more photopolymerization initiators selected from the group consisting of oxime ester-based photopolymerization initiators having an oxime ester group, alkyl phenyl ketone-based photopolymerization initiators, α-aminoacetophenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and diacene-based photopolymerization initiators may be used.

[0072] Examples of α-aminoacetophenone-based photopolymerization initiators include 2-methyl-1-(4-methylthiophenyl)-2-morpholinylpropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butane-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, and N,N-dimethylaminoacetophenone. Commercially available products include Omnirad 907, Omnirad 369, and Omnirad 379 manufactured by IGMresins B.V.

[0073] Examples of acylphosphine oxide photopolymerization initiators include 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide. Commercially available products include Omnirad TPO manufactured by IGMresins and Omnirad 819 manufactured by IGMresins B.V.

[0074] Specifically, examples of the aforementioned titanium-based photopolymerization initiators include bis(cyclopentadienyl)-diphenyltitanium, bis(cyclopentadienyl)-titanium dichloride, bis(cyclopentadienyl)-bis(2,3,4,5,6-pentafluorophenyl)titanium, and bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyrrolo-1-yl)phenyl)titanium. Commercially available examples include Omnirad 784 manufactured by IGMresins B.V.

[0075] As photopolymerization initiators, thioxanthone-based and benzophenone-based photopolymerization initiators are preferred. Isopropyl thioxanthone-based and 4,4'-bis(diethylamino)benzophenone are more preferred. Using thioxanthone-based and acylphosphine oxide-based photopolymerization initiators can yield cured patterns with excellent deep curing properties and suppressed undercutting. Commercially available products include ITX manufactured by DKSH JAPAN and EAB manufactured by Daido Chemical Industries, Ltd.

[0076] (B) The amount of photopolymerization initiator mixed with (A) is preferably 3 parts by mass or more and 25 parts by mass or less, more preferably 5 parts by mass or more and 23 parts by mass or less, and even more preferably 10 parts by mass or more and 20 parts by mass or less, based on 100 parts by mass of the carboxyl-containing resin in (A) as solids. By mixing the photopolymerization initiator within the above range, an alkaline developable curable resin composition (ink) with excellent photocurability and developability, as well as improved adhesion, can be obtained, thereby obtaining a cured product and a cured coating with excellent resistance to chemical gold plating.

[0077] (C) Antioxidants

[0078] In the alkaline developer-curable resin composition used in this invention, the antioxidant improves the adhesion between the substrate and the cured coating of the alkaline developer-curable resin composition by inhibiting the oxidation of the conductor (copper) on the substrate. Furthermore, through active research, the inventors have discovered that adding an antioxidant with a relatively large molecular weight and a relatively high melting point to the alkaline developer-curable resin composition—specifically, adding an antioxidant with a relative molecular weight of 600 g / mol or higher and 1200 g / mol or lower, and a melting point of 100°C or higher and 130°C or lower—can inhibit the thermal oxidation of organic compounds caused by high-temperature processes, further improving the adhesion between the ink and the copper surface, thereby enhancing the acid resistance, chemical gold plating resistance, electrolytic gold plating resistance, and tin resistance of the cured coating. Conversely, if the relative molecular weight of the antioxidant used is lower than 600 g / mol and the melting point is lower than 100°C, the tin resistance will not be improved. If the melting point of the antioxidant used is too high, above 130°C, crystalline particles may precipitate, leading to poor ink dispersion and coarsening.

[0079] From the perspective of effectively utilizing the effects of the present invention, the antioxidant (C) used in the present invention is preferably a hindered phenolic antioxidant. From the viewpoint of improving acid resistance and electrolytic gold plating performance, a hindered phenolic antioxidant with a molecular weight of 600 g / mol or more and 1200 g / mol or less is more preferred, and a hindered phenolic antioxidant with a molecular weight of 700 g / mol or more and 1200 g / mol or less is even more preferred. Furthermore, from the perspective of further exhibiting excellent heat resistance and tin resistance, and avoiding coarsening, a hindered phenolic antioxidant with a melting point of 100°C or more and 130°C or less is preferred, and a hindered phenolic antioxidant with a melting point of 110°C or more and 125°C or less is even more preferred.

[0080] Examples of hindered phenolic antioxidants include 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxellaspiro[5.5]undecane and pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate). Commercially available products meeting the above criteria include, for example, MIANOX AO-80 (manufactured by Nanjing Milan Chemical Co., Ltd.) and IRGANOX 1010 (manufactured by BASF).

[0081] From the perspective of effectively achieving the above-mentioned effects, the content of the antioxidant (C) is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 8 parts by mass or less, and even more preferably 2 parts by mass or more and 7 parts by mass or less, relative to 100 parts by mass of the carboxyl-containing resin (A) based on solid components.

[0082] (D) Barium sulfate

[0083] In this invention, the inventors discovered through active research that adding small-particle-size (D) barium sulfate that has undergone special pre-coating treatment to an alkaline developing type curable resin composition can improve the density of the coating film, thereby enhancing the resistance of the cured product to chemical gold plating and electrolytic gold plating, and also improving its resistance to tin plating.

[0084] (D) The average particle size of barium sulfate is expressed as D50 (the particle size value corresponding to 50% of the cumulative particle size distribution). The average particle size (D50) of barium sulfate is 0.5 μm or less, preferably 0.4 μm or less, and more preferably 0.3 μm or less. When the average particle size exceeds 0.5 μm, there is a concern about whitening of the pattern layer, and the acid resistance and electroless gold plating resistance are poor, especially the acid resistance and electroless gold plating resistance, so it is not preferred. There is no particular limitation on the lower limit of the average particle size of barium sulfate, for example, it is 0.01 μm or more. When the average particle size of barium sulfate is within the above range, the acid resistance, electroless gold plating resistance and electrolytic gold plating resistance of the cured product can be improved, and the resistance to tin plating can also be improved.

[0085] The average particle size (D50) can be determined using a laser diffraction-based particle size distribution measuring device and a device based on dynamic light scattering. Examples of laser diffraction-based measuring devices include the Microtrac MT3300EXII manufactured by MicrotracBEL Corp., and examples of dynamic light scattering-based measuring devices include the Nanotrac Wave II UT151 manufactured by MicrotracBEL Corp.

[0086] Regarding the amount of barium sulfate (D), relative to 100 parts by weight of the carboxyl-containing resin (A) based on solids, the content of barium sulfate (D) is preferably 100 parts by weight or more and 250 parts by weight or less, more preferably 110 parts by weight or more and 220 parts by weight or less, further preferably 120 parts by weight or more and 220 parts by weight or less, and most preferably 125 parts by weight or more and 220 parts by weight or less. Further, the mass ratio of barium sulfate (D) to antioxidant (C) is preferably 100 parts: 0.5 to 3.5 parts, more preferably 100 parts: 0.8 to 3.3 parts, further preferably 100 parts: 1.2 to 3.2 parts, and most preferably 100 parts: 1.5 to 3.1 parts.

[0087] If the amount of barium sulfate is too small, the effect of improving the acid resistance, chemical gold plating resistance, and electrolytic gold plating resistance of the cured product will be reduced, and the effect of improving the tin resistance will not be fully realized. If the amount is too large, it may lead to poor adhesion, which will further reduce the acid resistance, chemical gold plating resistance, electrolytic gold plating resistance, and tin resistance.

[0088] From the perspective of further improving the resistance of cured products to chemical gold plating and electrolytic gold plating, and enhancing resistance to tin plating, barium sulfate that has been surface-treated with amines is preferred, especially barium sulfate with amines substituted with hydroxyalkyl groups having 1 to 6 carbon atoms, such as barium sulfate surface-treated with triethanolamine. Including surface-treated barium sulfate suppresses interfacial disruption between the filler and the resin, further improving adhesion, acid resistance, and resistance to chemical gold plating. If the amount of surface-treated barium sulfate is within the above-mentioned range, an alkaline developing type curable resin composition with superior resistance to chemical gold plating, acid resistance, electrolytic gold plating, and resistance to tin plating can be obtained, while also saving on solvent usage. Commercially available barium sulfate surface-treated with triethanolamine, such as B-33 (manufactured by Sakai Chemical Industry Co., Ltd.), is an example.

[0089] (E) Talc

[0090] In order to improve the acid resistance of the alkaline developer-curable resin composition and maintain its excellent electroplating gold properties and tin resistance, the alkaline developer-curable resin composition of the present invention contains talc as an essential component.

[0091] Regarding the amount of talc used, the mass ratio of (D) barium sulfate to (E) talc is preferably 100 parts: 2 to 7 parts, more preferably 100 parts: 3 to 6 parts, and even more preferably 100 parts: 4 to 5 parts. If the amount of talc is insufficient, the acid resistance will be inadequate. On the other hand, if the amount of talc is too large, the acid resistance, excellent electrolytic gold plating properties, and tin resistance cannot be maintained.

[0092] Commercially available talcs include SG-2000, SG-200, SG-200N15 (manufactured by Japan Talc Co., Ltd.), and HD25 (manufactured by Fushi (Shanghai) Trading Co., Ltd.).

[0093] filler

[0094] In addition to (D) barium sulfate and (E) talc mentioned above, the present invention may optionally include other fillers. These fillers may be used individually or in combination of two or more, provided that the effects of the present invention are not impaired. The amount of filler mixed relative to 100 parts by weight of (A) carboxyl-containing resin (based on solids) is preferably in the range of 1 part by weight or more and 20 parts by weight or less, more preferably in the range of 3 parts by weight or more and 15 parts by weight or less, and most preferably in the range of 5 parts by weight or more and 10 parts by weight or less. When the amount of filler mixed is in the range of 1 part by weight or more and 20 parts by weight or less, it can suppress the curing shrinkage of the cured product, improve its adhesion, hardness, and other properties, and tends to produce a cured coating with superior resistance to tin oxide, insulation reliability, and heat discoloration resistance.

[0095] Examples of fillers include inorganic fillers such as titanium dioxide, amorphous silica, fused silica, spherical silica, barium titanate, Neuburg silica, clay, magnesium carbonate, calcium carbonate, alumina, aluminum hydroxide, silicon nitride, aluminum nitride, boron nitride, and Neuburg diatomaceous earth, as well as organic modified fillers such as bentonite. Commercially available bentonite includes BENATHIX GEL (BENATHIX's base product, manufactured by Elementis Specialties, Inc.).

[0096] Epoxy resin

[0097] Without impairing the effects of the invention, the invention may also include an epoxy resin. The epoxy resin functions as a thermosetting component in the alkaline developer-type resin composition to form a cured product. Commonly known multifunctional epoxy resins having at least two epoxy groups per molecule can be used as such epoxy resins. The epoxy resin can be liquid, solid, or even semi-solid.

[0098] Preferred multifunctional epoxy resins include bisphenol A type epoxy resins; brominated epoxy resins; phenolic varnish type epoxy resins; bisphenol F type epoxy resins; hydrogenated bisphenol A type epoxy resins; glycidylamine type epoxy resins; hydantoin type epoxy resins; alicyclic epoxy resins; trihydroxyphenylmethane type epoxy resins; bixylenol type or biphenol type epoxy resins or mixtures thereof; bisphenol S type epoxy resins; bisphenol A phenolic varnish type epoxy resins; and tetrahydroxyphenylethane type epoxy resins. Resins; heterocyclic epoxy resins; diglycidyl phthalate resins; tetraglycidyl dimethyl ethane resins; naphthyl-containing epoxy resins; epoxy resins with a dicyclopentadiene backbone; glycidyl methacrylate copolymer epoxy resins; copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate; epoxy-modified polybutadiene rubber derivatives; CTBN-modified epoxy resins; epoxy resins with isocyanurate rings, etc., but are not limited to these.

[0099] These epoxy resins can be used in one or in combination of two or more.

[0100] The phrase "epoxy resin that is solid or semi-solid at room temperature" can also use commonly known and commonly used types. Examples of epoxy resins that are solid at room temperature include: TGIC epoxy resin (manufactured by Shanghai Xindi Chemical Co., Ltd.), bisphenol A type epoxy resin (Y134 CA90, Guangming Chemical (Huzhou) Co., Ltd.), bisphenol F type epoxy resin (manufactured by Mitsubishi Chemical Corporation jER4004P), naphthalene type epoxy resin (manufactured by DIC Corporation HP-4700), multifunctional solid epoxy resin containing a naphthalene skeleton (manufactured by Nippon Kayaku Co., Ltd. NC-7000), triphenol epoxy resin (manufactured by Nippon Kayaku Co., Ltd. EPPN-502H), and multifunctional solid epoxy resin containing a dicyclopentadiene skeleton (manufactured by DIC Corporation Epiclon). Examples of epoxy resins that are semi-solid at room temperature include HP-7200, phosphorus-containing epoxy resin (TX0712 manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd.), and tris(2,3-epoxypropyl)isocyanurate (TEPIC manufactured by Nissan Chemical Industries, Ltd.). Examples of epoxy resins that are semi-solid at room temperature include bisphenol A type epoxy resin (jER834 manufactured by Mitsubishi Chemical Corporation) and naphthalene type epoxy resin (HP-4032 manufactured by DIC Corporation).

[0101] Here, in this invention, "solid or semi-solid at room temperature" means "solid or semi-solid at 15°C". The determination of whether something is solid or semi-solid can be made according to Annex 2, "Method for Confirmation of Liquid State", of the Ministry Ordinance concerning the testing and properties of hazardous materials (Ministry of Home Affairs Ordinance No. 1 of 1962).

[0102] As a biphenyl-type epoxy resin, commonly known multifunctional epoxy resins with a biphenyl backbone can be used. Examples include multifunctional solid epoxy resins containing a biphenyl backbone (NC-3000H and NC-3000 manufactured by Nippon Kayaku Co., Ltd.) and biphenyl-type epoxy resins (YX-4000 and YL-6121HA manufactured by Mitsubishi Chemical Co., Ltd.).

[0103] Examples of phenolic varnish-type epoxy resins include cresol phenolic varnish-type epoxy resin (Epiclon N-690 manufactured by DIC Corporation), phenolic varnish-type epoxy resin (Epiclon N-770 manufactured by DIC Corporation, and jER152 manufactured by Mitsubishi Chemical Corporation), and bisphenol A phenolic varnish-type epoxy resin (BNE200D75 manufactured by Shanghai Hongze Chemical Co., Ltd.).

[0104] Examples of epoxy resins containing isocyanurate rings include triglycidyl isocyanurate epoxy resin (TGIC-G manufactured by Shanghai Xindi Chemical Co., Ltd.).

[0105] The epoxy resin content described above is preferably approximately 20 parts by mass and 70 parts by mass and less, more preferably 40 parts by mass and 60 parts by mass and less, relative to 100 parts by mass of carboxyl-containing resin (A) based on solids.

[0106] Photosensitive monomers

[0107] Without impairing the effects of the invention, the invention may further include a photosensitive monomer. The photosensitive monomer may be a commonly known photosensitive monomer. It may be a compound having one or more olefinic unsaturated groups in its molecule. Such a photosensitive monomer facilitates (in the case of containing olefinic unsaturated groups) the photocuring of (A) carboxyl-containing resin based on active energy ray irradiation, thereby curing the alkaline developer-curable resin composition.

[0108] Preferred photosensitive monomers used in this invention include, for example, methyl α-(allyloxymethyl)acrylate, or diacrylates of diols such as 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and 1,10-decanediol diacrylate, as well as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, and tripropylene glycol diacrylate. Diacrylates of glycols, polypropylene glycol diacrylates, neopentyl glycol diacrylates, diacrylates of glycols obtained by adding at least one of ethylene oxide and propylene oxide to neopentyl glycol, diacrylates of caprolactone-modified hydroxypentanoic acid neopentyl glycol diacrylates, diacrylates of bisphenol A EO adducts, diacrylates of bisphenol A PO adducts, tricyclodecanediethanol diacrylates, hydrogenated dicyclopentadienyl diacrylates, cyclohexyl diacrylates, etc. Diacrylates having a cyclic structure, or difunctional (meth)acrylates such as their corresponding methacrylate monomers, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolmethane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, epichlorohydrin-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, tetramethylolmethane tetraacrylate, ethylene oxide-modified phosphate triacrylate, epichlorohydrin-modified glycerol triacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxy pentaacrylate, or polyfunctional acrylates represented by their sesquioxane-modified derivatives, or their corresponding methacrylate monomers, trifunctional methacrylates, ε-caprolactone-modified tris(acryloyloxyethyl)isocyanurate, or combinations of two or more thereof. Specifically, it can be a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate. As a commercially available product, MT3501A (manufactured by Zhangjiagang Dongya Di'ai Chemical Co., Ltd.) can be cited as an example.

[0109] The content of this photosensitive monomer relative to 100 parts by weight of the carboxyl-containing resin (A) based on solids is preferably 1 part by weight or more and 30 parts by weight or less, more preferably 15 parts by weight or more and 25 parts by weight or less.

[0110] solvent

[0111] In this invention, solvents may be used for general purposes, such as to adjust the viscosity of alkaline developing and curing resin compositions.

[0112] The solvent can be a conventional organic solvent, 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 (DPM), dipropylene glycol diethyl ether, and tripropylene glycol monomethyl ether; polyol ethers; alkyl esters of organic acids like ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate (CA), butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; polyol esters; aliphatic hydrocarbons like octane and decane; and petroleum-based solvents like petroleum ether, petroleum naphtha, solvent naphtha, and heavy aromatic solvent naphtha. These conventional organic solvents can be used alone or in combination of two or more.

[0113] Relative to 100 parts by weight (A) of carboxyl-containing resin based on solid content, the solvent content in the alkaline developing type curable resin composition of the present invention is preferably 50 parts by weight or more and 100 parts by weight or less, more preferably 55 parts by weight or more and 90 parts by weight or less, and even more preferably 60 parts by weight or more and 80 parts by weight or less.

[0114] Any other ingredients

[0115] In the alkaline developing and curing resin composition of the present invention, without departing from the purpose of the present invention, further additives may be added as other components as needed.

[0116] Examples of such components include colorants such as pigments and dyes, heat-resistant polymerization inhibitors, thermosetting catalysts, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, volatility agents, antioxidants, antibacterial / mildew inhibitors, defoamers, leveling agents, rheology modifiers, anti-sagging agents, thickeners, adhesion promoters, thixotropic promoters, photoinitiators, sensitizers, photoalkalizing agents, thermoplastic resins, elastomers, organic fillers, mold release agents, surface treatment agents, dispersants, dispersing aids, surface modifiers, stabilizers, phosphors, and cellulose resins.

[0117] Melamine is preferably added. As an antioxidant, it improves the adhesion between the substrate and the cured film of the thermosetting composition by inhibiting the oxidation of the conductor (copper) on the substrate. As a thermosetting catalyst, it can improve the acid and alkali resistance, metal plating resistance, adhesion, and hardness of the dry film and cured film formed by the alkaline developer-curing resin composition. Commercially available melamine products include MELAMINE FUNSAN manufactured by Kunshan Qiangwei Powder Equipment Co., Ltd.

[0118] Commercially available products that can be used as other ingredients include, for example, the base of green color paste 6Y-501 manufactured by TOYOCOLORCO.,LTD. as a colorant, KS-66 manufactured by Shin-Etsu Chemical Industry Co., Ltd. as a defoamer, and BYK-057 manufactured by BYK Additives (Shanghai) Co., Ltd. as a defoamer.

[0119] The amounts of other components can be optionally added within the conventional range in the art. For example, the amount of melamine can be 5 to 20 parts by weight, preferably 8 to 15 parts by weight, relative to 100 parts by weight of the carboxyl-containing resin (A) based on solids; the amount of colorant can be 2 to 15 parts by weight, preferably 4 to 10 parts by weight; and the amount of defoamer can be 1 to 10 parts by weight, preferably 2 to 6 parts by weight.

[0120] The alkaline developer-curable resin composition of the present invention is suitable for forming printed circuit boards, more suitable for forming permanent coatings, and most suitable for forming cover layers or solder resist layers, etc.

[0121] dry film

[0122] Dry films can be prepared from the alkaline developable curable resin composition of the present invention. The dry film of the present invention has a resin layer, which is obtained by coating a carrier film with the alkaline developable curable resin composition of the present invention and then drying it. When forming the dry film, the alkaline developable curable resin composition of the present invention can be directly or diluted with a solvent to an appropriate viscosity as needed, and then coated onto the carrier film to a uniform thickness using a comma coater, doctor blade coater, lip coater, bar coater, extrusion coater, reverse coater, transfer roller coater, gravure coater, spray coater, etc. The coated composition is then dried, typically at a temperature of 50–130°C, for 1–30 minutes to form the resin layer. There are no particular limitations on the coating film thickness; a range of 10–150 μm, preferably 20–60 μm, based on the dried film thickness, is generally suitable.

[0123] Plastic films are commonly used as carrier films, such as polyester films (PET), polyimide films, polyamide-imide films, polypropylene films, and polystyrene films. There are no particular restrictions on the thickness of the carrier film; a range of 10–150 μm is generally suitable.

[0124] After forming a resin layer of the alkaline developer-type curable resin composition of the present invention on the carrier film, in order to prevent dust or the like from adhering to the surface of the resin layer, it is preferable to further laminate a peelable cover film on the surface of the resin layer. Examples of peelable cover films include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper. The cover film need to be less than the adhesion between the resin layer and the carrier film when peeling it off.

[0125] It should be noted that, in this invention, the alkaline developer-type curable resin composition of this invention can also be coated onto the aforementioned cover film and dried to form a resin layer, upon which a carrier film is then laminated. That is, in this invention, when manufacturing the dry film, both a carrier film and a cover film can be used as the thin film for coating the curable composition of this invention.

[0126] Here, the alkaline developer-type curable resin composition of the present invention is adjusted to a viscosity suitable for the coating method using a solvent, and then coated onto a substrate by methods such as dip coating, flow coating, roller coating, bar coating, screen printing, or curtain coating. After drying (temporary drying) by evaporating the solvent contained in the composition at a temperature of approximately 30 to 100°C, a non-sticky resin layer can also be formed. Alternatively, when the above composition is coated onto a carrier film or cover film and dried to form a dry film, it can be laminated onto the substrate using a laminator or similar means, with the layer of the composition of the present invention in contact with the substrate, and then the carrier film can be peeled off to form a resin layer.

[0127] As the aforementioned substrate, in addition to printed circuit boards and flexible printed circuit boards with circuits pre-formed from copper or the like, examples include: copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer boards, etc. The copper-clad laminates use materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, and copper-clad laminates for high-frequency circuits using materials such as fluorinated polyethylene, polyphenylene ether (polyphenylene oxide), and cyanate.

[0128] Cured material

[0129] When forming a cured product using the alkaline developable curable resin composition of the present invention, the composition is coated onto a substrate, and after the solvent evaporates and dries, a resin layer is obtained. The obtained resin layer is then exposed (illuminated), thereby curing the exposed portion (the portion exposed to light). Specifically, using a contact or non-contact method, a patterned photomask is selectively exposed using active energy rays, or the pattern is directly exposed using a laser direct exposure machine. The unexposed portion is developed using an alkaline aqueous solution (e.g., a 0.3–3% by mass sodium carbonate aqueous solution), thereby forming a resist pattern. Further heating to a temperature of approximately 100–180°C is performed for thermal curing (post-curing), thereby forming a cured product (cured coating) with excellent properties such as heat resistance and pencil hardness.

[0130] The volatile drying or thermal curing of the solidified material can be carried out using, for example, a hot air circulating drying oven, an IR oven, a hot plate, a convection oven, etc. (using a device equipped with a heat source that uses steam to heat the air, and using a method of convection contact of hot air in the dryer and blowing it onto the support using nozzles).

[0131] Exposure machines used for irradiation with active energy rays can be direct drawing devices (e.g., laser direct imaging devices that directly draw images using lasers based on CAD data from a computer), exposure machines equipped with metal halide lamps, exposure machines equipped with (ultra) high-pressure mercury lamps, exposure machines equipped with mercury short-arc lamps, or direct drawing devices using ultraviolet lamps such as (ultra) high-pressure mercury lamps. For example, devices manufactured by companies such as Orbotech Ltd. and PENTAX CORPORATION can be used; any device capable of oscillating and generating lasers with a maximum wavelength of 350–410 nm can be used.

[0132] As an active energy beam, a laser with a maximum wavelength in the range of 350–410 nm is preferred. By using a wavelength within this range, free radicals can be efficiently produced by a photopolymerization initiator. Any type of laser, such as a gas laser or a solid-state laser, can be used, as long as it falls within this range. Furthermore, the exposure dose varies depending on factors such as film thickness, typically ranging from 5 to 500 mJ / cm². 2 The preferred range is 10–300 mJ / cm³. 2 The range.

[0133] As a developing method, methods such as immersion, showering, spraying, and brushing can be used. Additionally, as the developing solution, a sodium carbonate aqueous solution with a mass concentration of 0.5–5% can typically be used, or other alkaline aqueous solutions can be used, such as alkaline aqueous solutions of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc. In this developing process, the developing solution temperature is 20–40°C, and the developing time is within 180 seconds.

[0134] It should be noted that during this developing process, the resulting patterned film is cleaned with a rinsing solution as needed. The rinsing solution can be distilled water, methanol, ethanol, isopropanol, etc., used alone or in combination.

[0135] Electronic components

[0136] In addition, the present invention can also provide electronic components having the above-mentioned cured material.

[0137] The alkaline developing and curing resin composition or dry film of the present invention can be used as a protective film, electrical insulating layer, sealant, sealing material for embedded electronic components, component embedding layer, adhesive layer for fixing electronic components, etc., for printed circuit boards, semiconductor components, etc. It is particularly suitable for high-density wiring requiring low dielectric constant and low dielectric loss tangent, electronic components for processing high frequency signals, and electronic components for automotive and robotic applications requiring high temperature and long-term reliability.

[0138] It should be noted that, in this invention, electronic components refer to components used in electronic circuits, including not only active components such as printed circuit boards, transistors, light-emitting diodes, and laser diodes, but also passive components such as resistors, capacitors, inductors, and connectors.

[0139] Example

[0140] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products. Furthermore, unless otherwise specified, "parts" and "%" below refer to mass measurements.

[0141] [Examples 1-4 and Comparative Examples 1-12]

[0142] The components shown in Table 1 were premixed in a mixer at their respective mixing amounts, and then kneaded using a three-roll mill to prepare alkaline developing type curable resin compositions for Examples 1-4 and Comparative Examples 1-12, respectively.

[0143] [Evaluation Methods and Benchmarks]

[0144] The alkaline developable curable resin compositions obtained in Examples 1-4 and Comparative Examples 1-12 were evaluated as follows.

[0145] Evaluation substrate

[0146] The following characteristics were determined using the evaluation substrate described below.

[0147] The alkaline developable and curable resin compositions of the various embodiments and comparative examples were screen-printed onto a patterned copper foil laminate to achieve a dry film thickness of 20 μm. The laminate was dried at 80°C for 30 minutes and then cooled to room temperature. For this substrate, an exposure apparatus equipped with a high-pressure mercury lamp was used at 300 mJ / cm². 2 The pattern is exposed by the exposure amount, and then a 1 wt% sodium carbonate aqueous solution at 30°C is developed for 60 seconds under a spray pressure of 0.2 MPa. Then it is heated at 150°C for 60 minutes to cure it, thus obtaining an evaluation substrate with a cured coating.

[0148] Using the obtained evaluation substrate, the following evaluations were conducted on acid resistance, chemical gold plating resistance, electrolytic gold plating resistance, chemical tin resistance, and recrystallization (coarsening).

[0149] Acid resistance evaluation

[0150] The evaluation substrates were immersed in a 10 vol% H2SO4 aqueous solution at room temperature for 20 minutes, 30 minutes, and 40 minutes, respectively. The penetration and dissolution of the cured coating were visually confirmed to further confirm peeling caused by tape removal. The judgment criteria are as follows.

[0151] ○: No changes were observed.

[0152] △: Only slight changes

[0153] ×: The coating is bulging, swollen, or peeling.

[0154] Evaluation of resistance to chemical gold plating

[0155] Commercially available electroless nickel plating baths and electroless gold plating baths were used to perform plating at nickel thicknesses of 0.1 μm and gold thicknesses of 0.03 μm, respectively. The presence of peeling of the cured coating and penetration of the plating solution were evaluated by tape peeling. The criteria for evaluation are as follows.

[0156] ○: No infiltration or peeling was found.

[0157] △: Slight penetration was confirmed after plating, and peeling was also observed after the tape was removed.

[0158] ×: Peeling occurred after plating.

[0159] Evaluation of electrolytic gold plating

[0160] Apply direct current to plate until the appropriate gold plating thickness is achieved (Au: 0.03μm, Ni: 0.1μm). Observe the appearance of the cured film to see if copper leakage and whitening occur. Evaluate whether the cured film has peeled off by peeling off the tape. The evaluation is carried out according to the following standards.

[0161] ○: No copper leakage or whitening was found, and no peeling was performed.

[0162] △: After confirming obvious whitening or peeling, peeling was found.

[0163] ×: Significant copper leakage has been confirmed.

[0164] Evaluation of tin resistance

[0165] Using an evaluation substrate, after applying a 1.5 μm thick layer of chemically bonded tin (Sn) (reaction process described below), the appearance of the cured film was observed for copper leakage and whitening. The presence of peeling was evaluated by tape removal, and the evaluation was conducted according to the following standards. Cu(s) + Sn 2+ (aq)→Cu 2+ (aq)+Sn(s)

[0166] In this reaction, Cu represents copper, Sn represents tin, s indicates a solid state, and aq indicates an aqueous solution. During the reaction, copper ions are replaced by tin ions, forming a solid tin layer.

[0167] ○: No copper leakage or whitening was found, and no peeling was performed.

[0168] △: After confirming obvious whitening or peeling, peeling was found.

[0169] ×: Significant copper leakage has been confirmed.

[0170] Recrystallization evaluation (re-coarsening)

[0171] After storing the alkaline developer-curable resin composition obtained above at -5°C for 5 days, remove it and allow it to warm to room temperature (around 25°C). Then, use a squeegee fineness gauge (0–50 μm) to confirm the size of the ink particles. If the fineness gauge reading is 35 μm or higher, it indicates that when the film thickness of the cured coating of the composition is 20–25 μm, particles and poor appearance will occur. Therefore, a result of 35 μm or higher confirmed by the fineness gauge is marked as ×. Conversely, no coarseness or coarseness particles smaller than 35 μm are marked as 0.

[0172] [Table 1]

[0173] The components listed in Table 1 are as follows.

[0174] *1: Cresol phenolic resin varnish containing carboxyl groups, the specific preparation method is as follows:

[0175] 214 parts of EPICLON N-695 (manufactured by DIC, epoxy equivalent = 214) of cresol varnish-type epoxy resin was added to a four-necked flask equipped with a stirrer and a reflux condenser. 103 parts of carbitol acetate and 103 parts of petroleum-based hydrocarbon solvent (manufactured by Japan Energy Corporation, trade name: Cactus Fines SF-01) were added and heated to dissolve. Next, 0.1 parts of hydroquinone as a polymerization inhibitor and 2.0 parts of triphenylphosphine as a reaction catalyst were added. The mixture was heated to 95–105°C, and 72 parts of acrylic acid were slowly added dropwise, allowing the reaction to proceed for 16 hours. The resulting reaction product was cooled to 80–90°C, and 91.2 parts of tetrahydrophthalic anhydride were added, allowing the reaction to proceed for 8 hours. After cooling, the product was removed to obtain a cresol varnish-type carboxyl-containing resin as (A) carboxyl-containing resin. The non-volatile component of the cresol phenolic resin varnish obtained by this operation is 65%, and the acid value of the solid component is 87.5 mgKOH / g.

[0176] *2: Bentonite, BENATHIX GEL, BENATHIX Base Products, manufactured by Elementis Specialties, Inc.

[0177] *3: Green pigment paste, base product of 6Y-501, manufactured by TOYOCOLOR CO.,LTD.

[0178] *4: Hindered phenolic antioxidant, MIANOX BHT, 2,6-di-tert-butyl-4-methylphenol, relative molecular mass 220.35 g / mol, melting point 69–73℃, manufactured by Nanjing Milan Chemical Co., Ltd.

[0179] *5: Thioester antioxidant, MIANOX 412S, pentaerythritol tetra(3-lauryl thiopropionate), relative molecular mass 1161.9 g / mol, melting point 48~54℃, manufactured by Nanjing Milan Chemical Co., Ltd.

[0180] *6: Hindered phenolic antioxidant, RIANOX 1098, N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide), relative molecular mass 637 g / mol, melting point 156~162℃, manufactured by Tianjin Lianlong New Material Co., Ltd.

[0181] *7: Hindered phenolic antioxidant, MIANOX AO-80, 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, relative molecular mass 740.98 g / mol, melting point 110~125℃, manufactured by Nanjing Milan Chemical Co., Ltd.

[0182] *8: Hindered phenolic antioxidant, IRGANOX 1010, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), relative molecular mass 1177.65 g / mol, melting point 110–125 °C, manufactured by BASF.

[0183] *9: Defoamer, KS-66, manufactured by Shin-Etsu Chemical Industry Co., Ltd.

[0184] *10: Defoamer, BYK-057, manufactured by BYK Additives (Shanghai) Co., Ltd.

[0185] *11: Photopolymerization initiator, EAB, 4,4'-bis(diethylamino)benzophenone, manufactured by Daido Chemical Industry Co., Ltd.

[0186] *12: Photopolymerization initiator, ITX, isopropylthioxanthone, manufactured by DKSH JAPAN.

[0187] *13: Photopolymerization initiator, #907 (Omnirad 907), α-aminoacetophenone-based photopolymerization initiator, 2-methyl-1-(4-methylthiophenyl)-2-morpholinylpropane-1-one, manufactured by IGMresins B.V.

[0188] *14: Talc, HD25, manufactured by Fushi (Shanghai) Trading Co., Ltd.

[0189] *15: Melamine, manufactured by Kunshan Qiangwei Powder Equipment Co., Ltd.

[0190] *16: Solvent, DPM, dipropylene glycol monoether, manufactured by Taiwan LyondellTech Co., Ltd.

[0191] *17: Barite, 5AA, barium sulfate content >95%, whiteness ≥94%, moisture ≤0.2%, particle size D50: 1.65±0.2μm, manufactured by Guizhou Jingcheng Nanopowder Development Co., Ltd.

[0192] *18: Barium sulfate, AY-A2, barium sulfate content >98%, whiteness ≥98%, moisture ≤0.3%, particle size D50: 0.75±0.15μm, manufactured by Foshan Anyi Nanomaterials Co., Ltd.

[0193] *19: Barium sulfate, B-30, barium sulfate content >93%, silicon dioxide <10%, aluminum hydroxide <10% (surface treated with SiO2-Al2O3, no amines used), particle size D50: <0.4μm, manufactured by Sakai Chemical Industry Co., Ltd.

[0194] *20: Surface-treated barium sulfate, B-33, barium sulfate content >93%, silica <10%, aluminum hydroxide <10%, amine additive (triethanolamine) <5%, particle size D50: <0.3μm, manufactured by Sakai Chemical Industry Co., Ltd.

[0195] *21: Silica, CS-1002, whiteness ≥90%, moisture ≤0.2%, oil absorption 40~50g / 100g, particle size D50: 3.0±0.5μm, manufactured by Jiangsu Lianrui New Material Co., Ltd.

[0196] *22: Bisphenol A type epoxy resin (90% solids), Y134 CA90, manufactured by Guangming Chemical (Huzhou) Co., Ltd.

[0197] *23: Epoxy resin, TGIC, manufactured by Shanghai Xindi Chemical Co., Ltd.

[0198] *24: Multifunctional acrylic monomer, a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (100% solids), MT3501A, manufactured by Zhangjiagang Dongya Di'ai Chemical Co., Ltd.

[0199] As shown in Table 1, the cured product of the alkaline developing type curable resin composition of the present invention has excellent acid resistance, good resistance to chemical gold plating and electrolytic gold plating, and excellent resistance to tin plating without any coarsening.

[0200] On the other hand, the alkaline developing and curing resin compositions obtained in Comparative Examples 1-5 did not use antioxidant (C), resulting in poor acid resistance (40 min). Except for Comparative Example 4, their electrolytic gold plating performance was also poor (as shown in Figures 5, 6, and 7). Although barium sulfate (D) was used, the average particle size of the barium sulfate used in Comparative Example 1 was too large, as shown in Figure 1. Its resistance to chemical gold plating at 0.1 μm (nickel) was poor, and its acid resistance (30, 40 min), electrolytic gold plating performance, and resistance to tin plating were all poor. Although the barium sulfate used in Comparative Example 2 underwent surface treatment, the substance used for surface treatment was SiO2-Al2O3 rather than an amine. While its resistance to chemical gold plating at 0.1 μm (nickel) was somewhat improved, its acid resistance (30, 40 min) and electrolytic gold plating performance were still poor. The electroplating gold resistance and tin resistance were still poor. The barium sulfate used in Comparative Example 3 was not surface treated. Although the electroplating gold resistance (0.1 μm) was significantly improved, its acid resistance (30, 40 min), electroplating gold resistance, and tin resistance were still poor. The barium sulfate used in Comparative Example 4 was surface treated with triethanolamine. The electroplating gold resistance (0.1 μm) was significantly improved, and the acid resistance (30 min) was also excellent. However, since no antioxidant was used, there was still room for improvement in electroplating gold resistance (as shown in Figure 4) and tin resistance. In Comparative Example 5, silicon dioxide was used as an inorganic filler. Its electroplating gold resistance (0.1 μm) (as shown in Figure 2), acid resistance (30, 40 min), electroplating gold resistance, and tin resistance were all poor.

[0201] Although Comparative Examples 6-9 used barium sulfate with surface treatment and a specific average particle size, the resistance to chemical gold plating was significantly improved. However, as an antioxidant, the antioxidant used in Comparative Example 6 had a small molecular weight and a low melting point. Although it improved the acid resistance and electrolytic gold plating to some extent, there was still room for improvement, and the tin resistance evaluation results were still poor. The antioxidant used in Comparative Example 7 was a thioester antioxidant with a low melting point. Although it improved the acid resistance and electrolytic gold plating to some extent, there was still room for improvement, and the tin resistance evaluation results were still poor. The antioxidants used in Comparative Examples 8 and 9 had higher melting points. Comparative Example 8, which used a larger amount, showed significant improvement in acid resistance (40 min), chemical gold plating resistance, electrolytic gold plating resistance, and tin resistance. However, due to the high melting point of the antioxidant used, after a period of time, crystalline particles would precipitate when it came into contact with ink monomers, resulting in poor ink dispersion and a poor roughness evaluation. Comparative Example 9 had poor results in both acid resistance (40 min) and roughness evaluation.

[0202] Comparative Examples 10-12 did not use talc. Compared with Comparative Example 1, Comparative Example 10 also had poorer acid resistance (20 min). Furthermore, Comparative Example 10 did not use an antioxidant, and the average particle size of the barium sulfate used was too large, resulting in poor resistance to electroless gold plating (0.1 μm) (as shown in Figure 3), electrolytic gold plating, and tin plating. Although Comparative Examples 11 and 12 used specific antioxidants and surface-treated barium sulfate with a specific average particle size, the acid resistance (40 min), electrolytic gold plating, and tin plating resistance of Comparative Example 11 were poor due to the lack of talc. Similarly, the acid resistance (40 min), electrolytic gold plating, and tin plating resistance of Comparative Example 12 were also poor.

[0203] In contrast, Examples 1-4 combine an antioxidant with a specific relative molecular weight and a specific melting point, barium sulfate with a specific surface treatment and a specific average particle size, with a carboxyl-containing resin, a photopolymerization initiator, and talc. This results in a cured product that exhibits excellent acid resistance, good resistance to chemical gold plating, and good resistance to electrolytic gold plating (as shown in Figures 8 and 9). At the same time, it also exhibits excellent resistance to chemical tin plating without any coarsening.

[0204] Industrial availability

[0205] The alkaline developer-curable resin composition of the present invention is particularly suitable for cured products of printed circuit boards using photolithography, dry films having a resin layer formed by the alkaline developer-curable resin composition on a carrier film, and electronic components having the cured product.

Claims

1. An alkaline, developer-curable resin composition, characterized in that, It contains (A) carboxyl-containing resin, (B) photopolymerization initiator, (C) antioxidant, (D) barium sulfate, and (E) talc. The antioxidant (C) has a relative molecular weight of 600 g / mol or higher and 1200 g / mol or lower, and a melting point of 100°C or higher and 130°C or lower. The (D) barium sulfate is barium sulfate with an average particle size of less than 0.5 μm that has been surface-treated with amine substances.

2. The alkaline developing and curing resin composition according to claim 1, characterized in that, The content of barium sulfate in (D) is 100 parts by mass or more and 250 parts by mass or less, relative to 100 parts by mass of the carboxyl-containing resin (A) based on solid content.

3. The alkaline developing and curing resin composition according to claim 1 or 2, characterized in that, The mass ratio of barium sulfate (D) to antioxidant (C) is 100 parts: 0.5 to 3.5 parts.

4. The alkaline developing and curing resin composition according to claim 1 or 2, characterized in that, The mass ratio of (D) barium sulfate to (E) talc is 100 parts: 2 to 7 parts.

5. The alkaline developing and curing resin composition according to claim 1 or 2, characterized in that, The antioxidant (C) mentioned above is a hindered phenolic antioxidant.

6. The alkaline developing and curing resin composition according to claim 1 or 2, characterized in that, The (D) barium sulfate is barium sulfate that has been surface-treated with triethanolamine.

7. A dry film, characterized in that, It has a resin layer on a carrier film, said resin layer being formed from any one of the alkaline developable curable resin compositions according to claims 1 to 6.

8. A cured product, characterized in that, It is obtained by curing the alkaline developing type curable resin composition according to any one of claims 1 to 6.

9. A cured product, characterized in that, It is obtained by curing the resin layer of the dry film as described in claim 7.

10. An electronic component, characterized in that, The cured product having the characteristics of claim 8 or 9.

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