Photosensitive dry film, photosensitive resin composition, cured film, and printed circuit board

Abstract

This application discloses a photosensitive dry film, a photosensitive resin composition, a cured film, and a printed circuit board, belonging to the field of materials technology. The ratio of the thickness of the photosensitive dry film to the median particle size D50 of the inorganic filler in this application is (4-8):1, and the ratio of the thickness of the photosensitive dry film to the maximum particle size D100 of the inorganic filler is greater than 2.8. Through the above design, this application achieves the creation of barriers and / or extension of the penetration and diffusion path in the small molecule diffusion pathway, thereby extending the time for small molecules to reach the dry film and copper interface, thus reducing or suppressing the influence of small molecule substances on the interface copper oxide, and improving interlayer adhesion, chemical resistance, and reliability.

Description

Technical Field

[0001] This application relates to the field of materials technology, and more specifically, to a photosensitive dry film, a photosensitive resin composition, a cured film, and a printed circuit board. Background Technology

[0002] With the trend towards thinner and more modular PCBs, the corresponding circuit design spacing is becoming smaller and the patterns are becoming more intricate. This places increasingly higher demands on the performance of solder mask materials. The solder mask layer must maintain its insulating protective function while being thinner. Thinner solder mask layers are less able to resist the penetration of small molecules. Moisture, acids, alkalis, and other small molecules can easily diffuse within the solder mask layer and reach the interface between the solder mask and copper in a short time, exacerbating the erosion and damage to the interface. This weakens the insulating protective effect of the solder mask layer on the copper, making it very easy for problems such as reduced insulation and short circuits to occur, affecting the normal use and lifespan of the final device. Currently, high-end PCBs require solder mask materials with low film thickness, good acid resistance, resistance to various surface treatments (including nickel-gold plating, nickel-palladium-gold plating, etc.), and high reliability (including PCT, HAST aging, ion migration, etc.).

[0003] Therefore, there is an urgent need to research a solder resist material with good chemical resistance that can solve the above problems. Summary of the Invention

[0004] The main objective of this application is to provide a photosensitive dry film, a photosensitive resin composition, a cured film, and a printed circuit board to solve the problem that the existing PCB solder mask layer has poor chemical resistance and cannot provide good insulation protection for the copper substrate.

[0005] To achieve the above objectives, according to one aspect of this application, a photosensitive dry film is provided, comprising a base film and an inorganic filler distributed in the base film; wherein the ratio of the thickness of the photosensitive dry film to the median particle size D50 of the inorganic filler is (4-8):1, and the ratio of the thickness of the photosensitive dry film to the maximum particle size D100 of the inorganic filler is greater than 2.8.

[0006] Furthermore, the ratio of the thickness of the photosensitive dry film to the median particle size D50 of the inorganic filler is (5-8):1.

[0007] Furthermore, the ratio of the thickness of the photosensitive dry film to the maximum particle size D100 of the inorganic filler is greater than or equal to 4, and further to 4 to 7.

[0008] Furthermore, the thickness of the photosensitive dry film is less than or equal to 100 μm; further still, it is 10–50 μm; even further, it is 15–40 μm; and still further, it is 20–40 μm.

[0009] Furthermore, the median particle size D50 of the inorganic filler is 2.5–8.0 μm, and the maximum particle size D100 is less than or equal to 10 μm.

[0010] Furthermore, the inorganic filler includes inorganic filler I; wherein inorganic filler I is selected from at least one of titanium dioxide, barium sulfate, silicon dioxide and aluminum hydroxide.

[0011] Furthermore, the median particle size D50 of inorganic filler I is 2.5–8.0 μm, and the maximum particle size D100 is less than or equal to 10 μm.

[0012] Furthermore, the inorganic filler also includes inorganic filler II; wherein inorganic filler II is flaky mica powder and / or flaky talc powder.

[0013] Furthermore, the median particle size D50 of inorganic filler II is 1–10 μm, and the maximum particle size D100 is less than or equal to 15 μm.

[0014] Furthermore, the median particle size D50 of inorganic filler II is 3–7 μm; and the maximum particle size D100 is less than or equal to 10 μm.

[0015] Furthermore, the median particle size D50 of inorganic filler II is 3–7 μm, and the maximum particle size D100 is 5–10 μm.

[0016] Furthermore, the thickness of inorganic filler II is less than or equal to 1.5 μm.

[0017] Furthermore, the thickness of inorganic filler II is 0.5–1.0 μm.

[0018] Furthermore, inorganic filler II is distributed in the base membrane in a manner substantially parallel to the surface of the base membrane.

[0019] Furthermore, the raw materials for the base film include alkali-soluble vinyl resin.

[0020] Furthermore, the alkali-soluble vinyl resin is selected from at least one of carboxylic acid-modified bisphenol A type epoxy vinyl resin, carboxylic acid-modified bisphenol F type epoxy vinyl resin, carboxylic acid-modified bisphenol S type epoxy vinyl resin, and carboxylic acid-modified phenolic epoxy vinyl resin.

[0021] According to a second aspect of this application, a resin composition for preparing the above-mentioned photosensitive dry film is provided, the raw materials of which include the following components in parts by weight: 100 parts of alkali-soluble vinyl resin, 10-30 parts of reactive diluent, 20-40 parts of thermosetting agent, 0.1-5 parts of photoinitiator, 15-45 parts of inorganic filler, and 0.1-3 parts of antioxidant.

[0022] Furthermore, the inorganic filler includes inorganic filler I; wherein inorganic filler I is selected from at least one of titanium dioxide, barium sulfate, silicon dioxide and aluminum hydroxide.

[0023] Furthermore, the morphology of inorganic filler I includes at least one of amorphous, angular, and spherical shapes.

[0024] Furthermore, inorganic packing I is solid packing and / or hollow packing; even further, it is solid packing.

[0025] Furthermore, the median particle size D50 of inorganic filler I is 2.5–8.0 μm, and the maximum particle size D100 is less than or equal to 10 μm.

[0026] Furthermore, the inorganic filler also includes inorganic filler II; wherein inorganic filler II is flaky mica powder and / or flaky talc powder.

[0027] Furthermore, the median particle size D50 of inorganic filler II is 1–10 μm, and the maximum particle size D100 is less than or equal to 15 μm.

[0028] Furthermore, the median particle size D50 of inorganic filler II is 3–7 μm, and the maximum particle size D100 is less than or equal to 10 μm.

[0029] Furthermore, the thickness of inorganic filler II is less than or equal to 1.5 μm.

[0030] Furthermore, the thickness of inorganic filler II is 0.5–1.0 μm.

[0031] Furthermore, the weight ratio of inorganic packing I to inorganic packing II is (11-17):(3-9).

[0032] Furthermore, inorganic filler I and / or inorganic filler II are surface modified with a modifying compound; wherein the modifying compound is an epoxy compound or an acrylic compound.

[0033] Furthermore, the alkali-soluble vinyl resin is selected from at least one of carboxylic acid-modified bisphenol A type epoxy vinyl resin, carboxylic acid-modified bisphenol F type epoxy vinyl resin, carboxylic acid-modified bisphenol S type epoxy vinyl resin, and carboxylic acid-modified phenolic epoxy vinyl resin.

[0034] Furthermore, the acid value of the alkali-soluble vinyl resin is 50–100 mg KOH / g, and even further, it is 80–100 mg KOH / g.

[0035] Furthermore, the reactive diluent is selected from at least one of monofunctional reactive diluents, difunctional reactive diluents, trifunctional reactive diluents, and highly functional reactive diluents.

[0036] Furthermore, the monofunctional reactive diluent is selected from aromatic (meth)acrylates, alkoxy-dodecyl (meth)acrylates, alicyclic (meth)acrylates, 2-(2-ethoxyethoxy)ethyl acrylates, octadecyl (meth)acrylates, tetrahydrofuran (meth)acrylates, dodecyl (meth)acrylates, 2-phenoxyethyl (meth)acrylates, isodecanyl (meth)acrylates, alicyclic (meth)acrylates, octyl (meth)acrylates, isooctyl (meth)acrylates, tridecyl (meth)acrylates, caprolactone (meth)acrylates, and (4) ethoxylated nonylphenol (meth). At least one of the following: acrylate, isobornyl acrylate, trimethylolpropane formaldehyde (meth)acrylate, methoxy polyethylene glycol mono(meth)acrylate, methoxy polyethylene glycol (500) mono(meth)acrylate, alkoxylated tetrahydrofuran (meth)acrylate, alkoxylated nonylphenol (meth)acrylate, dimethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 4-hydroxybutyl vinyl ether, glyceryl carbonate propylene ether, and dodecyl vinyl ether.

[0037] Furthermore, the bifunctional reactive diluent is selected from cyclohexanediol di(meth)acrylate, alkylhexanediol di(meth)acrylate, alkylneopentyl glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol (200) di(meth)acrylate, triethylene glycol di(meth)vinyl ether, tetraethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and 1,4-cyclohexyldiethanol. At least one of the following: di(meth)alkenyl ether, ethylene glycol di(meth)acrylate, pentylene glycol di(meth)acrylate, polyethylene glycol (400) di(meth)acrylate, polyethylene glycol (600) di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A di(meth)acrylate, dipropylene glycol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, and propoxylated neopentyl glycol di(meth)acrylate.

[0038] Furthermore, the trifunctional active diluent is selected from at least one of tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, and propoxylated trimethylolpropane tri(meth)acrylate.

[0039] Furthermore, the highly functionalized reactive diluent is selected from at least one of di-trimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0040] Furthermore, the thermosetting agent includes at least one of the following: end-capped isocyanate compounds, amino resins, benzoxazine resins, carbodiimide resins, maleimide compounds, cyclic carbonate compounds, epoxy compounds, polyfunctional oxetane compounds, and cyclic sulfur resins.

[0041] Furthermore, the epoxy compound is selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy resin, brominated epoxy resin, hydroquinone type epoxy resin, biphenyl type crystalline epoxy resin, naphthalene type epoxy resin, thioether type epoxy resin, o-cresol varnish type epoxy resin, biphenyl phenolic varnish type epoxy resin, and tris(hydroxyphenylmethane) type epoxy resin. The resin is selected from at least one of the following: biphenol-type epoxy resin, bisphenol A phenolic varnish-type epoxy resin, tetramethylolethane-type epoxy resin, heterocyclic epoxy resin, diglycidyl phthalate resin, tetraglycidyl dimethylformyl ethane resin, dicyclopentadiene skeleton glycidyl methacrylate copolymer epoxy resin, cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resin, epoxy-modified polybutadiene rubber derivatives, and CTBN-modified epoxy resin.

[0042] Furthermore, the epoxy equivalent of the epoxy compound is 100–400 g / eq.

[0043] Furthermore, the polyfunctional oxetane compound is selected from at least one of bis[(3-methyl-3-oxetane-butylmethoxy)methyl] ether, bis[(3-ethyl-3-oxetane-butylmethoxy)methyl] ether, 1,4-bis[(3-methyl-3-oxetane-butylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetane-butylmethoxy)methyl]benzene, (3-methyl-3-oxetane-butyl)methyl acrylate, (3-ethyl-3-oxetane-butyl) methacrylate, (3-methyl-3-oxetane-butyl) methyl methacrylate, (3-ethyl-3-oxetane-butyl) methyl methacrylate and their oligomers or copolymers, oxetane alcohol, phenolic varnish resin, poly(p-hydroxystyrene), Cardo type bisphenol, calixarene, and calix-isophenylene diarylene.

[0044] Furthermore, the amino resin is selected from at least one of hydroxymethyl melamine compound, hydroxymethyl benzoguanamine compound, hydroxymethyl glycourea compound, and hydroxymethyl urea compound.

[0045] Furthermore, photoinitiators include pyrolysis-type free radical polymerization photoinitiators, hydrogen abstraction-type free radical polymerization photoinitiators, and cationic polymerization photoinitiators.

[0046] Furthermore, the cleavage-type free radical polymerization photoinitiator is selected from at least one of α-hydroxy ketone derivatives, α-amino ketone derivatives, acylphosphine oxides, and oxime esters.

[0047] Furthermore, the α-hydroxy ketone derivatives are selected from at least one of 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 1-[4-(2-hydroxy)-phenyl]-3-hydroxy-2-methyl-1-propanone-1-one.

[0048] Furthermore, the α-amino ketone derivative is selected from at least one of 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinylbenzylphenyl)butanone, and 2-p-methylbenzyl-2-dimethylamino-1-(4-morpholinylphenyl)-1-butanone.

[0049] Further, the acylphosphine oxide is selected from at least one of 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0050] Furthermore, the oxime esters are 1,8-bis[9-ethyl-6-nitro-9H-carbazole-3-yl]-,1,8-bis(O-acetyloxime) and / or 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime).

[0051] Furthermore, the hydrogen-abstracting free radical initiator is selected from at least one of benzophenone and its derivatives, thioxanthone and its derivatives, anthraquinone and its derivatives, or diacetic titanocene.

[0052] Furthermore, the thioxanthone is selected from at least one of 2,4-diethylthioxanthone, isopropylthioxanthone, and 1-chloro-4-propoxythioxanthone.

[0053] Furthermore, the diacene titanium compounds are selected from at least one of 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.

[0054] Furthermore, the cationic polymerization photoinitiator is selected from at least one of aryl diazonium salts, diaryliodonium salts, triaryl thiodonium salts, aryl ferrocene salts, and cumene ferrocene hexafluorophosphate.

[0055] Furthermore, the cationic polymerization photoinitiator is selected from at least one of dodecylbenzeneiodonium salt, long-chain alkoxydiphenyliodonium salt, phenylthiophenyldiphenylthiodonium salt, diphenylthiodonium hexafluoroantimonate, UV16976, UV16992, and UV261.

[0056] Furthermore, the antioxidant includes antioxidant I; wherein antioxidant I includes aromatic amine compounds and / or hindered phenolic compounds.

[0057] Furthermore, antioxidant I is selected from at least one of 2-tert-butylhydroquinone, hydroquinone monomethyl ether, pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylate, 2,6-di-tert-butyl-p-cresol, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, p-methoxyphenol, and phenothiazines.

[0058] Furthermore, antioxidants also include antioxidant II; wherein antioxidant II is a phosphorus-containing organic compound and / or a sulfur-containing organic compound.

[0059] Furthermore, antioxidant II is selected from at least one of triphenyl phosphite, pentaerythritol tetra(lauryl thioacrylate), and dilauryl thiodipropionate.

[0060] According to a third aspect, a curing film is provided, which is obtained by sequentially photocuring and thermal curing a photosensitive dry film; wherein the photosensitive dry film is the aforementioned photosensitive dry film or the aforementioned resin composition formed by drying.

[0061] According to a fourth aspect, a printed circuit board is provided, the printed circuit board including a copper plate and a curing film attached to the surface of the copper plate; wherein the curing film is the aforementioned curing film.

[0062] The present application provides a photosensitive dry film and its resin composition. Considering the thickness of the photosensitive dry film and the particle size of the filler particles, the ratio of the dry film thickness to the median particle size D50 of the inorganic filler is limited to (4-8):1, and the ratio of the dry film thickness to D100 is above 2.8. This achieves the creation of barriers and / or extension of the penetration and diffusion path in the small molecule diffusion pathway, thereby extending the time for small molecules to reach the dry film and copper interface, thus reducing or suppressing the influence of small molecule substances on the interface copper oxide, and further improving interlayer adhesion. Detailed Implementation

[0063] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments.

[0064] In its research on PCB solder mask materials, this application discovered that acidic solutions, electroless nickel-gold plating (ENEPIG), and nickel-palladium-gold plating (ENIG) solutions are all aqueous systems composed of small molecules. Small molecules such as sulfuric acid, hydrochloric acid, and phosphoric acid can slowly penetrate the dry film surface into the bulk material and reach the interface between the dry film and bare copper. These penetrating and diffused acidic molecules erode the copper oxide at the interface, reducing the contact points and resulting in decreased adhesion. To address this issue, this application found that by placing obstacles and / or extending the penetration and diffusion path of the acidic small molecules, the time it takes for them to reach the interface between the dry film and copper is prolonged. Within the same timeframe, the amount of etching of copper oxide by the acidic small molecules is lower or almost nonexistent, thereby improving the chemical resistance of the dry film. The aforementioned chemical resistance specifically refers to acid resistance, electroless nickel-gold plating (ENEPIG), and electroless nickel-gold plating (ENIG).

[0065] Therefore, this application provides a photosensitive dry film, which includes a base film and inorganic fillers distributed in the base film; wherein the ratio of the thickness of the photosensitive dry film to the median particle size D50 of the inorganic filler is (4-8):1, and the ratio of the thickness of the photosensitive dry film to the maximum particle size D100 of the inorganic filler is greater than 2.8.

[0066] The photosensitive dry film of this application has the characteristic of curing into a film under conditions such as light or heat. The photosensitive dry film refers to a dry film that has not yet undergone light curing and heat curing. The ratio of the thickness of the dry film to the particle size of the inorganic filler is any value of 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, or 8, or any value between any two. The ratio of the dry film thickness to the maximum particle size D100 of the inorganic filler in this application is greater than 2.8, and the ratio of the dry film thickness to D100 is less than the ratio of the dry film thickness to D50.

[0067] This application achieves the rational setting of barriers and / or extension of the penetration and diffusion path in small molecules by controlling the optimal ratio of dry film thickness to inorganic filler D50 and D100, respectively. This significantly prolongs the time for small molecules to reach the coating film and copper interface, thereby reducing or inhibiting the etching effect of acidic small molecules on the interface copper oxide, and significantly improving the chemical resistance of the dry film, such as acid resistance, electroless nickel-gold plating (ENEPIG), and electroless nickel-gold plating (ENIG); thus improving interlayer adhesion.

[0068] In some embodiments, the ratio of the thickness of the photosensitive dry film to the median particle size D50 of the inorganic filler is (5-8):1. By further optimizing the ratio of dry film thickness to D50, i.e., adjusting the median particle size D50 of the inorganic filler to a more suitable value, barriers are more rationally set and / or the permeation and diffusion path is extended in the acidic small molecule permeation and diffusion path, further extending the time for small molecules to reach the dry film and copper interface, thereby improving the chemical resistance and interlayer adhesion of the dry film.

[0069] In some embodiments, the ratio of the thickness of the photosensitive dry film to the maximum particle size D100 of the inorganic filler is greater than or equal to 4; for example, any value among 4, 5, 6, 7, 8, 9, and 10, or any value between the two; and for example, 4 to 7. By controlling the ratio of the dry film to the inorganic filler D100 within the above-mentioned preferred range, i.e., appropriately controlling the maximum particle size D100, the inorganic filler particles are made substantially uniform, improving the dispersibility of the filler in the base film, which is beneficial to improving the chemical resistance and interlayer adhesion of the dry film.

[0070] In some embodiments, the thickness of the photosensitive dry film is less than or equal to 100 μm; further, it is 10 to 50 μm; even further, it is 15 to 40 μm; and still further, it is 20 to 40 μm; for example, any value or range between 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 μm; the median particle size D50 of the inorganic filler is 2.5 to 8.0 μm, and the maximum particle size D100 is less than or equal to 10 μm. For example, D50 can be any value among 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, and 8, or any value between any two; and D100 can be any value among 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 μm, or any value between any two. This application, while further reducing the thickness of the dry film to meet the requirements of use, controls the particle size of inorganic fillers D50 and D100 to form suitable barriers and molecular penetration paths in the dry film, which can prolong the time for small molecules to reach the dry film and copper interface, thereby improving the chemical resistance and interlayer adhesion of the dry film.

[0071] In some embodiments, the inorganic filler includes inorganic filler I; wherein inorganic filler I is selected from at least one of titanium dioxide, barium sulfate, silicon dioxide, and aluminum hydroxide; the median particle size D50 of inorganic filler I is 2.5–8.0 μm, and the maximum particle size D100 is less than or equal to 10 μm; inorganic filler I is uniformly distributed in the base film. By selecting the above-mentioned inorganic filler I, adjusting more suitable D50, D100, and uniform distribution, the uniformity of filler distribution in the dry film can be improved, and a better pathway that can hinder the penetration of acidic small molecules to the copper interface can be designed, thereby improving the chemical resistance and adhesion of the dry film.

[0072] In some embodiments, the dry film thickness is 20 μm, the median particle size D50 of the inorganic filler is 2.5–4.0 μm, and the maximum particle size D100 is less than or equal to 5 μm; or, the dry film thickness is 40 μm, the median particle size D50 of the inorganic filler is 5–8 μm, and the maximum particle size D100 is less than or equal to 10 μm.

[0073] In some embodiments, in addition to inorganic filler I, inorganic filler II can also be added to the inorganic filler of this application; wherein inorganic filler II is flake mica powder and / or flake talc powder. Besides adding granular inorganic filler I to the base film, to further improve the effect of preventing acidic small molecules and other substances from penetrating to the copper interface, thin flake inorganic filler II can also be added to the base film, such as two-dimensional flake filler, which can be flake mica powder or flake talc powder; wherein, mica powder is a layered silicate, the structure of which is a complex silica layer composed of two layers of silicon-oxygen tetrahedra sandwiching a layer of aluminum-oxygen octahedra, completely dissociated, and can be split into extremely thin flakes, with a thickness of up to 1.5 μm or less, and a large aspect ratio. Its general chemical composition is SiO2: 43.13–49.04%, Al2O3: 27.93–37.44%, K... 2O+NaO: 9~11%, H2O: 4.13~6.12%, it is a flake-shaped fine powder product with a silvery-white to gray appearance. This flake-shaped filler II can form a basically parallel orientation arrangement in the solder resist film layer. Such layer-by-layer arrangement, its orientation is exactly perpendicular to the direction of corrosive substances penetrating the paint film, which can give full play to the barrier effect of its flake material, and strongly block the penetration of water and other corrosive substances in the dry film. When using high-quality mica powder, the time for water and other corrosive substances to penetrate the dry film can generally be extended by 3 times. It has good chemical stability and can improve the heat resistance, weather resistance, anti-chalking and durability of the solder resist film layer.

[0074] The median particle size D50 of mica powder is 1–10 μm, further 3–7 μm, for example, any value among 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or any range between two. The maximum particle size D100 is less than 15 μm, further less than 10 μm, and further further 5–10 μm, for example, any value among 2, 3, 4, 5, 6, 7, 8, 9, 10 μm or any range between two. The flake thickness is less than or equal to 1.5 μm, further less than or equal to 1.0 μm, and further further 0.5–10 μm; for example, any value among 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5 μm or any range between two. For example, filler II can be made of BT-30 material from Chuzhou Wanjuan New Material Co., Ltd. Excessive D50 and D100 values ​​of the aforementioned sheet-like fillers mainly affect PCT (Potential Corrosion Tolerance). Excessive D50 and D100 values ​​make dispersion difficult, negatively impacting the packing density of various fillers, leading to a decrease in PCT and a deterioration in nickel-gold resistance. Conversely, insufficient D50 and D100 values ​​result in insignificant barrier effects and lower PCT. Excessive thickness also hinders dispersion, negatively impacting nickel-gold resistance and PCT. This application, by adding the aforementioned specific proportions of inorganic filler I and inorganic filler II to the base film, utilizes the granular inorganic filler I to create a pathway that impedes the penetration of water or acidic small molecules from the outside to the copper interface. Furthermore, the sheet-like inorganic filler II provides a direct barrier effect. The synergistic effect of these two filler forms in the base film effectively prevents corrosive substances from penetrating to the copper interface.

[0075] In some embodiments, the raw material of the base film includes an alkali-soluble vinyl resin; the inorganic filler in the resin contains 15% to 45% by mass; the specific type of alkali-soluble vinyl resin is not limited, and commonly used alkali-soluble vinyl resins in the art are acceptable; for example, at least one of carboxylic acid-modified bisphenol A type epoxy vinyl resin, carboxylic acid-modified bisphenol F type epoxy vinyl resin, carboxylic acid-modified bisphenol S type epoxy vinyl resin, and carboxylic acid-modified phenolic epoxy vinyl resin. The selected alkali-soluble vinyl resin carries a certain number of double bonds, which can undergo photocuring reaction during exposure and be used as a macromolecular photopolymerization monomer; the selection of the above-mentioned alkali-soluble vinyl resin as the main material of the base film, this type of resin has good corrosion resistance and good adhesion to metallic copper; it further improves the overall chemical resistance of the dry film, such as acid resistance, electroless nickel-gold plating (ENEPIG), and electroless nickel-gold plating (ENIG).

[0076] In some embodiments, the acid value of the alkali-soluble vinyl resin is 50–100 mg KOH / g, more specifically 80–100 mg KOH / g. By limiting the alkali-soluble vinyl resin to the above-mentioned acid value, the developing effect can be significantly improved, problems such as poor developing and incomplete developing with residual resin can be avoided, and problems such as over-development leading to deviations in linewidth and line spacing from the standard values ​​can also be avoided, resulting in dry film with superior chemical resistance and reliability.

[0077] According to a second aspect of this application, a resin composition for preparing the above-mentioned photosensitive dry film is provided, the raw materials of which include the following components in parts by weight: 100 parts of alkali-soluble vinyl resin, 10-30 parts of reactive diluent, 20-40 parts of thermosetting agent, 0.1-5 parts of photoinitiator, 15-45 parts of inorganic filler, and 0.1-3 parts of antioxidant.

[0078] The resin composition described in this application, after drying, forms the aforementioned photosensitive dry film. The main resin material in this composition is an alkali-soluble vinyl resin. Due to its chemical structure, it can be used as a polymer monomer during subsequent photocuring. This material exhibits good corrosion resistance, strong adhesion to copper, and chemical stability. In addition, the added reactive diluent, besides reducing the viscosity of the resin composition, can also be used as another polymer monomer due to its specific chemical structure, further improving the subsequent photocuring reaction speed. The added filler is used to create complex pathways in the base film that can block small molecule corrosives from penetrating to the copper interface, significantly improving the film's chemical resistance and interlayer adhesion. The added antioxidant is used to avoid or eliminate the problem of increased small molecule penetration caused by defects resulting from resin composition aging. Even a small amount of antioxidant in the polymer system can delay or inhibit the polymer oxidation process, thereby preventing polymer aging and extending its service life. It can also eliminate generated free radicals or promote the decomposition of hydrogen peroxide, preventing chain reactions. The added thermosetting agent is used to improve the curing efficiency of the dry film curing into a solder resist film during subsequent use. The photoinitiator is used to enable the photosensitive dry film to undergo a polymerization reaction with the resin material after UV irradiation, thereby forming a cured film. This application does not limit the types of raw materials mentioned above. By adjusting the proportions of each component, a solder resist film layer with better chemical resistance, interlayer adhesion, and insulation can be obtained during the later curing process. In particular, by setting the content of inorganic fillers in the alkali-soluble vinyl resin, the overall chemical resistance of the dry film can be further improved. For example, based on 100 parts of alkali-soluble vinyl resin, the weight parts of the above-mentioned reactive diluent can be selected from any value among 10, 15, 20, 25, and 30 parts. The weight of the above-mentioned thermosetting agent can be selected from any value of 20, 25, 30, 35, or 40 parts or any value between any two; the weight of the above-mentioned photoinitiator can be selected from any value of 0.1, 0.5, 1, 2, 3, 4, or 5 parts or any value between any two; the weight of the above-mentioned filler can be selected from any value of 15, 20, 25, 30, 25, 40, or 45 parts or any value between any two; the above-mentioned antioxidant can be selected from any value of 0.1, 0.5, 1, 1.5, 2, 2.5, or 3 parts or any value between any two.

[0079] In some embodiments, the inorganic filler includes inorganic filler I; wherein inorganic filler I is selected from at least one of titanium dioxide, barium sulfate, silicon dioxide, and aluminum hydroxide; further, the morphology of inorganic filler I includes at least one of amorphous, angular, and spherical shapes; further still, inorganic filler I is a solid filler and / or a hollow filler; even further still, it is a solid filler; further still, the median particle size D50 of inorganic filler I is 2.5–8.0 μm, and the maximum particle size D100 is less than or equal to 10 μm. By selecting inorganic filler I with the above morphology and type, adjusting more suitable D50, D100, and uniform distribution, the uniformity of filler distribution in the dry film can be improved, and better pathways that can hinder the penetration of acidic small molecules to the copper interface can be designed, thereby improving the chemical resistance and adhesion of the dry film.

[0080] In some embodiments, the inorganic filler further includes inorganic filler II; wherein, inorganic filler II is flake mica powder and / or flake talc powder, mainly mica powder; further, the median particle size D50 of the mica powder is 1-10 μm, and even more specifically 3-7 μm, with a thickness of less than or equal to 1.5 μm and a large aspect ratio. By adding inorganic filler I and inorganic filler II to the base film, the particulate inorganic filler I forms a pathway that hinders the penetration of water or acidic small molecules from the outside to the copper interface. On this basis, the flake inorganic filler II plays another blocking role. The two forms of filler work together in the base film to effectively prevent corrosive substances from penetrating to the copper interface. By adding flake inorganic filler II, the chemical resistance time of the dry film can be improved. For example, the PCT resistance time of the dry film can be increased from 48h to 96h, but the flake filler... Adding too much may hinder the formation of the permeation path of particulate filler I, which in turn will lead to a decrease in the chemical resistance of the dry film; therefore, the weight ratio of inorganic filler I to inorganic filler II is (11~17):(3~9); for example, any value or any range between 1, 1.2, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5, 5.5, 6, 6.5; at this ratio, the two fillers with different morphologies can better achieve the obstruction path and improve the chemical resistance of the dry film through synergistic effect.

[0081] In some embodiments, inorganic filler I and / or inorganic filler II are surface-modified with a modifying compound; wherein the modifying compound is an epoxy compound or an acrylic compound. By modifying the inorganic filler as described above, the epoxy and acrylic compounds exhibit high compatibility with the membrane system, which can better improve the dispersibility of the filler in the resin, thereby improving the chemical resistance of the dry film.

[0082] In some embodiments, the alkali-soluble vinyl resin is selected from at least one of carboxylic acid-modified bisphenol A type epoxy vinyl resin, carboxylic acid-modified bisphenol F type epoxy vinyl resin, carboxylic acid-modified bisphenol S type epoxy vinyl resin, and carboxylic acid-modified phenolic epoxy vinyl resin. Selecting the above-mentioned alkali-soluble vinyl resin, which carries a certain number of double bonds, allows it to undergo photocuring during exposure and can be used as a macromolecular photopolymerization monomer. Choosing the above-mentioned alkali-soluble vinyl resin as the base film material provides good corrosion resistance and good adhesion to metallic copper, further improving the overall chemical resistance of the dry film, such as acid resistance, electroless nickel plating (ENEPIG), and electroless nickel plating (ENIG).

[0083] In some embodiments, to further improve the acid and alkali resistance of the dry film, the acid value of the alkali-soluble vinyl resin is 45–120 mg KOH / g, and further 80–100 mg KOH / g. For example, the acid value can be any value or a range between any two of 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, and 120 mg KOH / g. By limiting the alkali-soluble vinyl resin to the above-mentioned acid value, the developing effect can be significantly improved, problems such as poor developing and incomplete developing with residual resin can be avoided, and problems such as overdevelopment leading to deviations in linewidth and line spacing from standard values ​​can also be avoided, resulting in the dry film having superior chemical resistance and reliability.

[0084] In some embodiments, the reactive diluent is a vinyl-functionalized reactive diluent, and may be one or more of monofunctional, difunctional, trifunctional, and high-functionalized reactive diluents. The selected acrylate-based reactive diluent with the above-mentioned characteristics can better reduce the viscosity of the resin composition and has a certain degree of polymerizability, making it suitable as a photopolymerizable monomer and further improving the subsequent photocuring rate. Furthermore, the above-mentioned reactive diluent does not contain ethoxy or propoxy groups; even further, the glass transition temperature of the reactive diluent is -10°C to 80°C.

[0085] For example, the above-mentioned monofunctional reactive diluents can be selected from aromatic (meth)acrylates, alkoxy-dodecyl (meth)acrylates, alicyclic (meth)acrylates, 2(2-ethoxyethoxy)ethyl acrylates, octadecyl (meth)acrylates, tetrahydrofuran (meth)acrylates, dodecyl (meth)acrylates, 2-phenoxyethyl (meth)acrylates, isodecanyl (meth)acrylates, alicyclic (meth)acrylates, octyl (meth)acrylates, isooctyl (meth)acrylates, tridecyl (meth)acrylates, caprolactone (meth)acrylates, (4) ethoxylated nonylphenol (meth)acrylates. The following are at least one of the following: acrylate, isobornyl acrylate, trimethylolpropane formaldehyde (meth)acrylate, methoxy polyethylene glycol mono(meth)acrylate, methoxy polyethylene glycol (500) mono(meth)acrylate, alkoxylated tetrahydrofuran (meth)acrylate, alkoxylated nonylphenol (meth)acrylate, dimethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 4-hydroxybutyl vinyl ether, glyceryl carbonate propylene ether, and dodecyl vinyl ether.

[0086] For example, the aforementioned bifunctional reactive diluents can be selected from cyclohexanediol di(meth)acrylate, alkylhexanediol di(meth)acrylate, alkylneopentyl glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol (200) di(meth)acrylate, triethylene glycol di(meth)vinyl ether, tetraethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and 1,4-cyclohexyldiethanol di(meth)alkenyl ether. , at least one of the following: ethylene glycol di(meth)acrylate, pentylene glycol di(meth)acrylate, polyethylene glycol (400) di(meth)acrylate, polyethylene glycol (600) di(meth)acrylate, (3) ethoxylated bisphenol A di(meth)acrylate, ethoxylated (30) bisphenol A di(meth)acrylate, dipropylene glycol di(meth)acrylate, (4) ethoxylated bisphenol A di(meth)acrylate, (10) ethoxylated bisphenol A di(meth)acrylate, ethoxylated (20) bisphenol A di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, (2) propoxylated neopentyl glycol di(meth)acrylate, etc.

[0087] The trifunctional reactive diluent may be selected from at least one of the following: tri(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, (3) ethoxylated trimethylolpropane tri(meth)acrylate, (3) propoxylated trimethylolpropane tri(meth)acrylate, (6) ethoxylated trimethylolpropane tri(meth)acrylate, and (6) propoxylated trimethylolpropane tri(meth)acrylate.

[0088] The highly functional group active diluent can be selected from at least one of di-trimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, or dipentaerythritol hexa(meth)acrylate.

[0089] Furthermore, it should be noted that in the above-mentioned reactive diluents, "(meth)acrylate" refers to both "acrylate" and "methacrylate", "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid", and "(meth)acryloyloxy" refers to both "acryloyloxy" and "methacryloyloxy". Other components involving "(meth)" are similar. In the Chinese names of the above-mentioned bifunctional and trifunctional reactive diluents, the number in "(3)" indicates the number of ethoxy groups. For example, (3) ethoxylated bisphenol A di(meth)acrylate indicates bisphenol A di(meth)acrylate modified with 3 ethoxy groups. For another example, (200) in "polyethylene glycol (200)" refers to the average molecular weight of polyethylene glycol. Polyethylene glycol (400) and polyethylene glycol (600) are similar.

[0090] In some embodiments, the thermosetting agent includes at least one of a terminated isocyanate compound, an amino resin, a benzoxazine resin, a carbodiimide resin, a maleimide compound, a cyclic carbonate compound, an epoxy compound, a polyfunctional oxobutane compound, or a cyclic sulfur resin. The thermosetting agent can enable or promote the thermal crosslinking reaction of other components in the photosensitive resin composition, thereby improving the heat resistance of the cured product and its adhesion and bonding to the substrate.

[0091] The epoxy compounds mentioned above can be selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy resin, brominated epoxy resin, hydroquinone type epoxy resin, biphenyl type crystalline epoxy resin, naphthalene type epoxy resin, thioether type epoxy resin, o-cresol varnish type epoxy resin, biphenyl phenolic varnish type epoxy resin, trihydroxyphenylmethane type epoxy resin, etc. The epoxy resin is selected from at least one of the following: epoxy resin, biphenol-type epoxy resin, bisphenol A phenolic varnish-type epoxy resin, tetramethylolpropane-type epoxy resin, heterocyclic epoxy resin, diglycidyl phthalate resin, tetraglycidyl dimethylformyl ethane resin, dicyclopentadiene skeleton glycidyl methacrylate copolymer epoxy resin, cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resin, epoxy-modified polybutadiene rubber derivative, or CTBN-modified epoxy resin. The epoxy equivalent of the thermosetting agent is 100–400 g / eq; for example, any value from 100, 150, 200, 250, 300, 350, 400, or any range between two values. The selected thermosetting agent can achieve or promote the thermal crosslinking reaction of other components in the photosensitive resin composition, improving the heat resistance and adhesion and bonding strength of the cured product to the substrate.

[0092] The aforementioned polyfunctional oxetane compounds may be selected from at least one of the following: bis[(3-methyl-3-oxetane-butylmethoxy)methyl] ether, bis[(3-ethyl-3-oxetane-butylmethoxy)methyl] ether, 1,4-bis[(3-methyl-3-oxetane-butylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetane-butylmethoxy)methyl]benzene, (3-methyl-3-oxetane-butyl) methyl acrylate, (3-ethyl-3-oxetane-butyl) methacrylate, (3-methyl-3-oxetane-butyl) methyl methacrylate, (3-ethyl-3-oxetane-butyl) methyl methacrylate and their oligomers or copolymers, oxetane alcohol, phenolic varnish resin, poly(p-hydroxystyrene), Cardo type bisphenol, calixarene, and calix-isophenylene diaryl.

[0093] The aforementioned amino resin is a general term for resins formed by the condensation polymerization of amino-containing compounds such as urea, melamine, or benzene-containing melamine with formaldehyde or alcohols; amino resins may be selected from at least one of hydroxymethyl melamine compounds, hydroxymethyl benzoguanamine compounds, hydroxymethyl glycourea compounds, and hydroxymethyl urea compounds. Further, the aforementioned thermosetting agent includes at least one of epoxy compounds, polyfunctional oxobutane compounds, or amino resins.

[0094] Furthermore, this application may select a nitrogen-containing six-membered heterocyclic compound (CN117706870A) as an active diluent and / or as a thermosetting agent. This nitrogen-containing six-membered heterocyclic compound can improve the heat resistance and adhesion of the photosensitive dry film, reduce edge biting, reduce side etching, and has excellent nickel-gold properties.

[0095] In some embodiments, the photoinitiator includes a free radical polymerization photoinitiator (pyrolysis type or hydrogen abstraction type) and / or a cationic polymerization photoinitiator; wherein, the pyrolysis type free radical polymerization photoinitiator includes α-hydroxy ketone derivatives, α-amino ketone derivatives, acylphosphine oxides, oxime esters, etc.; the hydrogen abstraction type free radical initiator includes benzophenone and its derivatives, thioxanthone and its derivatives, anthraquinone and its derivatives, and may also be a diocene type.

[0096] For example, α-hydroxy ketone derivatives can include 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 1-[4-(2-hydroxy)-phenyl]-3-hydroxy-2-methyl-1-propanone-1-one; commercially available products include Omnirad 184 and Omnirad 1173 manufactured by IGM Resins.

[0097] As α-aminoketone derivatives, they can be 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinylbenzylphenyl)butanone, 2-p-methylbenzyl-2-dimethylamino-1-(4-morpholinylphenyl)-1-butanone, etc.; commercially available products include Omnirad 907, Omnirad 369, Omnirad 379 manufactured by IGM Resins.

[0098] Acylphosphine oxides can be 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, etc., and commercially available products include Omnirad TPO, Omnirad 819, Omnirad TPO-L, etc.

[0099] Oxime ester photoinitiators can include 1,8-bis[9-ethyl-6-nitro-9H-carbazole-3-yl]-, 1,8-bis(O-acetyl oxime), 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime), etc., and commercially available products include OXE-01 and OXE-02 manufactured by BASF, and NCI-831 and N-1919 manufactured by ADEKA CORPORATION.

[0100] Thioxanthone photoinitiators can include 2,4-diethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxythioxanthone, etc., with commercially available products such as ITX and DETX.

[0101] For use as a titanium terephthalate photopolymerization initiator, bis(cyclopentadienyl)-diphenyltitanium, bis(cyclopentadienyl)-titanium dichloride, bis(cyclopentadienyl)-bis(2,3,4,5,6-pentafluorophenyl)titanium, bis(cyclopentadienyl)-bis(2,6,-difluoro-3-(pyrrolo-1-yl)phenyl)titanium, etc. can be selected; commercially available products include Omnirad 784 manufactured by IGM Resins BV.

[0102] Cationic polymerization photoinitiators include, but are not limited to, any one or a mixture of two or more of aryl diazonium salts, diaryl iodomonium salts, triaryl thiomonium salts, aryl ferrocene salts, and isopropylbenzene ferrocene hexafluorophosphate. Commercially available products include didodecylbenzeneiodomonium salts, long-chain alkoxydiphenyliodomonium salts, phenylthiophenyl diphenylthiomonium salts, diphenylthiomonium hexafluoroantimonate, UV16976, UV16992, and UV261.

[0103] In this application, antioxidants are added during reliability testing to avoid or eliminate the problem of increased small molecule penetration caused by defects resulting from resin composition aging. Even a small amount of antioxidant in the polymer system can delay or inhibit the polymer oxidation process, thereby preventing polymer aging and extending its service life. The role of antioxidants is to eliminate newly generated free radicals or promote the decomposition of hydroperoxides, preventing chain reactions.

[0104] In some embodiments, the antioxidant includes antioxidant I; wherein antioxidant I includes aromatic amine compounds and / or hindered phenolic compounds, such as aromatic amines and hindered phenols and their derivatives. Antioxidant I, as the primary antioxidant, can capture and eliminate free radicals, preventing oxidative degradation of resins, etc.; furthermore, antioxidant I is selected from at least one of 2-tert-butylhydroquinone, hydroquinone monomethyl ether, pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylate, 2,6-di-tert-butyl-p-cresol, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, p-methoxyphenol, and phenothiazines; commercially available products include: Irganox 1010, Irganox 1076, Irganox 1135, Tinuvin 292, Tinuvin 152, Tinuvin... 5100, etc. Antioxidants may also include antioxidant II as a co-antioxidant, which can decompose hydroperoxides, mainly phosphorus-containing organic compounds and / or sulfur-containing organic compounds; for example: at least one of triphenyl phosphite, pentaerythritol tetra(lauryl thioacrylate), and dilauryl thiodipropionate; as commercially available products such as: Mark Ao-412S, AdekastabTPP, etc.

[0105] In the presence of inorganic filler I and inorganic filler II, an excessive amount of inorganic filler II may decrease chemical resistance. However, by adding a suitable antioxidant, the high-temperature and damp-heat aging performance of the dry film can be further improved without changing the amount of sheet filler. The PCT tolerance time can be increased from 96h to 120h, significantly extending the dry film's resistance to high temperatures and boiling water. This application combines spherical inorganic filler I, sheet-like inorganic filler II, and antioxidants. The synergistic effect of these three components simultaneously improves the chemical resistance and reliability of the photosensitive dry film.

[0106] The aforementioned reliability test PCT refers to the pressure cooker steaming test, with a temperature of 121℃, humidity of 100%, pressure of 0.2MPa, and a time of 96h. In the PCT test, the solder resist layer will inevitably undergo aging and degradation of some or all of the polymer chains due to prolonged exposure to high temperature and water vapor. Small molecules such as water vapor and acid will attack the solder resist layer from the weak points where aging and degradation have occurred, which is directly manifested as blistering or cracking of the solder resist layer. In the destructive tensile test, the solder resist layer will fall off and the adhesion will be reduced.

[0107] According to a third aspect of this application, a method for preparing the aforementioned dry film is provided: first, raw materials are prepared according to the proportions of each component; then, alkali-soluble vinyl resin, reactive diluent, thermosetting agent, photoinitiator, filler, and antioxidant are mixed to form a slurry; then, the slurry is coated onto a substrate and dried to form a film.

[0108] To facilitate the transportation and storage of the dry film, the aforementioned substrate is used to support the dry film, and a protective film is then covered on the surface of the dry film; the materials of the aforementioned substrate and / or the aforementioned protective film can be PET / PBT / PEN / PP / PE / release paper, etc.

[0109] In the above methods, the uniformity of filler dispersion has a significant impact on the appearance and performance of the coating film. Filler agglomeration can lead to an uneven surface, orange peel effect, or reduced gloss. Furthermore, filler agglomeration increases the microporosity of the coating film, weakening its barrier effect against water and other corrosive substances, thus reducing chemical resistance. Therefore, this application designs a two-step method for dispersing fillers, including a slurry preparation process and a coating process. The slurry preparation process includes the following steps:

[0110] Step S1: Add the filler to the solvent under ultrasonic conditions, and obtain the filler pre-dispersion after ultrasonic dispersion;

[0111] Step S2: Add filler pre-dispersion liquid to alkali-soluble vinyl resin under stirring, and obtain slurry after stirring.

[0112] Specifically, the solvent and dispersant are mixed and placed in a high-power ultrasonic device. The required fillers (such as filler I and filler II) are slowly added under ultrasonic conditions. After all fillers are added, ultrasonication continues for 2 hours. More specifically, the resin is first added to a high-speed mechanical dispersion device and stirred for 2 hours, maintaining a constant temperature of 40°C. At this temperature, the resin viscosity is lower. Then, the filler pre-dispersion obtained from the first ultrasonic dispersion is slowly added under medium-speed stirring. After continuing medium-speed stirring for 2 hours, high-speed sand milling is performed to finally obtain a fine slurry.

[0113] Specifically, in step S1, the ultrasonic dispersion time is 1.5 to 2.5 hours; in step S2, the alkali-soluble vinyl resin is controlled at a constant temperature of 35 to 45°C, and then the filler pre-dispersant is added, and the mixture is stirred at medium speed for another 1.5 to 2.5 hours (2 hours) to obtain the above slurry.

[0114] According to the fourth aspect, a curing film is provided, which is obtained by sequentially photocuring and thermal curing a photosensitive dry film; wherein the photosensitive dry film is the aforementioned photosensitive dry film or the aforementioned resin composition formed by drying.

[0115] Specifically, the above photocuring requires a Stoutffer exposure scale of 9 to 11 / 21; the above thermal curing conditions include a temperature of 150 to 180°C and a time of 60 to 90 minutes.

[0116] According to a fifth aspect, a printed circuit board is provided, the printed circuit board including a copper plate and a curing film attached to the surface of the copper plate; wherein the curing film is the aforementioned curing film.

[0117] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0118] The raw materials used in the embodiments and comparative examples of this application are existing technologies and are all commercially available.

[0119] Example 1

[0120] This embodiment 1 provides a photosensitive dry film with excellent chemical resistance; the dry film thickness is 20μm; filler I is spherical silica with a median particle size D50 of 2.5μm and a maximum particle size D100 of 4.8μm; filler II is flake mica powder with a median particle size D50 of 3.3μm, a maximum particle size D100 of 8.0μm, and a thickness of 0.5μm;

[0121] The resin composition of the above-mentioned photosensitive dry film includes: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solid content 65.3%, Nippon Kayaku), 10.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 20.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 0.1g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), 10.5g of silica (D50 2.5μm, D100 4.8μm, solid, commercially available), 4.5g of mica powder (BT-30, D50 3.3μm, D100 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Materials Co., Ltd.), and 0.1g of antioxidant 1010 (BASF).

[0122] Example 2

[0123] This embodiment 2 provides a photosensitive dry film with excellent chemical resistance; the dry film thickness is 20μm, filler I is spherical silica with a median particle size D50 of 2.5μm and a maximum particle size D100 of 4.8μm; filler II is flake mica powder with a median particle size D50 of 3.3μm, a maximum particle size D100 of 8.0μm, and a thickness of 0.5μm;

[0124] The resin composition of the above-mentioned photosensitive dry film includes: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 30.0g of tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 40.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 5.0g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide (TPO, Tianjin Jiuri New Materials), 24.75g of silica (D50 2.5μm, D100 4.8μm, solid, commercially available), and 20.25g of mica powder (BT-30, D50 3.3μm, D100... 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Material Co., Ltd.), 3.0g antioxidant 1010 (BASF).

[0125] Example 3

[0126] This embodiment 3 provides a photosensitive dry film with excellent chemical resistance; the dry film thickness is 20 μm, filler I is spherical silica with a median particle size D50 of 4.0 μm and a maximum particle size D100 of 5.0 μm; filler II is flake mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 0.5 μm;

[0127] The resin composition of the above-mentioned photosensitive dry film includes: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 20.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 20.0g of triglycidyl isocyanate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), 25.5g of silica (D50 4.0μm, D100 5.0μm, solid, commercially available), 4.5g of mica powder (BT-30, D50 3.3μm, D100 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Materials Co., Ltd.), and 1.5g of antioxidant 1010 (BASF).

[0128] Example 4

[0129] This embodiment 4 provides a photosensitive dry film with excellent chemical resistance; the dry film thickness is 20 μm, filler I is spherical silica with a median particle size D50 of 4.0 μm and a maximum particle size D100 of 5.0 μm; filler II is flake mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 0.5 μm;

[0130] The resin composition of the above-mentioned photosensitive dry film includes: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids 65.3%, Nippon Kayaku), 20.0g of tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 40.0g of triglycidyl isocyanurate triglycidyl ester (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), 16.5g of silica (D50 4.0μm, D100 5.0μm, solid, commercially available), and 13.5g of mica powder (BT-30, D50 3.3μm, D100... 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Material Co., Ltd.), 1.5g antioxidant 1010 (BASF).

[0131] Example 5

[0132] This embodiment 5 provides a photosensitive dry film with excellent chemical resistance; the dry film thickness is 40 μm, filler I is spherical silica with a median particle size D50 of 5.0 μm and a maximum particle size D100 of 7.5 μm; filler II is flake mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 0.5 μm;

[0133] The resin composition of the above-mentioned photosensitive dry film includes: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 5.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 5.0g of tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 20.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide (TPO, Tianjin Jiuri New Materials), 8.25g of silica (D50 5.0μm, D100 7.5μm, solid, commercially available), and 6.75g of mica powder (BT-30, D50 3.3μm, D100... 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Material Co., Ltd.), 1.5g antioxidant 1010 (BASF).

[0134] Example 6

[0135] This embodiment 6 provides a photosensitive dry film with excellent chemical resistance. The dry film thickness is 40 μm. Filler I is spherical silica with a median particle size D50 of 8.0 μm and a maximum particle size D100 of 9.8 μm; filler II is flake mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 0.5 μm.

[0136] The resin composition of the above-mentioned photosensitive dry film includes: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 10.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 10.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 10.0g of triglycidyl isocyanate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide (TPO, Tianjin Jiuri New Materials), 31.5g of silica (D50 8.0μm, D100 9.8μm, solid, commercially available), and 13.5g of mica powder (BT-30, D50 3.3μm, D100... 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Material Co., Ltd.), 0.15g antioxidant 1010 (BASF).

[0137] Example 7

[0138] This embodiment 7 provides a photosensitive dry film with excellent chemical resistance. The dry film thickness is 40 μm. Filler I is spherical silica with a median particle size D50 of 8.0 μm and a maximum particle size D100 of 9.8 μm; filler II is flake mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 0.5 μm.

[0139] The resin composition of the above-mentioned photosensitive dry film includes: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 12.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 12.0g of tris(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 15.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 15.0g of triglycidyl isocyanate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide (TPO, Tianjin Jiuri New Materials), 21.0g of silica (D50 8.0μm, D100 9.8μm, solid, commercially available), and 9.0g of mica powder (BT-30, D50...). 3.3μm, D100 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Material Co., Ltd.), 3.0g antioxidant 1010 (BASF).

[0140] Example 8

[0141] The difference between Example 8 and Example 1 is that the thickness of the photosensitive dry film is 10 μm, and the filler I is selected as spherical silica with a median particle size D50 of 2.5 μm and a maximum particle size D100 of 3.5 μm.

[0142] Example 9

[0143] The difference between Example 9 and Example 8 is that the filler I is selected as spherical barium sulfate with a median particle size of D50 1.5 μm and a maximum particle size of D100 2 μm.

[0144] Example 10

[0145] The difference between Example 10 and Example 9 is that the filler I is selected as amorphous barium sulfate with a median particle size D50 of 1.5 μm and a maximum particle size D100 of 2 μm.

[0146] Example 11

[0147] The difference between Example 11 and Example 9 is that the filler I is selected as angular barium sulfate with a median particle size D50 of 1.5 μm and a maximum particle size D100 of 2 μm.

[0148] Example 12

[0149] The difference between Example 12 and Example 7 is that the film thickness is 50 μm.

[0150] Example 13

[0151] The difference between Example 13 and Example 7 is that the film thickness is 100 μm, and the filler I is selected as spherical silica with a median particle size D50 of 12.5 μm and a maximum particle size D100 of 14.5 μm.

[0152] Example 14

[0153] The difference between Example 14 and Example 1 is that the filler I is hollow silica.

[0154] Example 15

[0155] The difference between Example 15 and Example 1 is that filler I is selected as spherical titanium dioxide.

[0156] Example 16

[0157] The difference between Example 16 and Example 1 is that spherical alumina is selected as filler I.

[0158] Example 17

[0159] This embodiment 17 provides a photosensitive dry film with excellent chemical resistance; the film thickness is 20μm, and the filler I is selected as spherical silica with a median particle size D50 of 2.5μm and a maximum particle size D100 of 4.8μm.

[0160] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 12.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 12.0g of tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 15.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 15.0g of triglycidyl isocyanate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), 30.0g of silica (D50 2.5μm, D100 4.8μm, solid, commercially available), and 1.5g of antioxidant 1010 (BASF).

[0161] Example 18

[0162] The difference between Example 18 and Example 1 is that filler II is selected as flaky mica powder with a median particle size of 50 7 μm, a maximum particle size of 100 10 μm, and a thickness of 0.5 μm.

[0163] Example 19

[0164] The difference between Example 19 and Example 1 is that filler II is selected as flaky mica powder with a median particle size of D50 1μm, a maximum particle size of D100 5μm, and a thickness of 0.5μm.

[0165] Example 20

[0166] The difference between Example 20 and Example 1 is that filler II is selected as flaky mica powder with a median particle size of D50 10μm, a maximum particle size of D100 15μm, and a thickness of 0.5μm.

[0167] Example 21

[0168] The difference between Example 21 and Example 1 is that filler II is selected as flaky mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 1 μm.

[0169] Example 22

[0170] The difference between Example 22 and Example 1 is that filler II is selected as flaky mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 1.5 μm.

[0171] Example 23

[0172] The difference between Example 23 and Example 1 is that filler II is selected as flaky talc powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 0.5 μm.

[0173] Example 24

[0174] This embodiment 24 provides a photosensitive dry film with excellent chemical resistance; the film thickness is 20μm, and the filler I is selected as spherical silica with a median particle size D50 of 2.5μm and a maximum particle size D100 of 4.8μm.

[0175] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 12.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 12.0g of tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 15.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemicals, Japan), 15.0g of triglycidyl isocyanate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), and 30.0g of silica (D50 2.5μm, D100 4.8μm, solid, commercially available).

[0176] Example 25

[0177] This embodiment 25 provides a photosensitive dry film with excellent chemical resistance; the dry film thickness is 20 μm, filler I is selected as spherical silica with a median particle size D50 of 2.5 μm and a maximum particle size D100 of 4.8 μm; filler II is selected as flake mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 0.5 μm;

[0178] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 12.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 12.0g of tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 15.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 15.0g of triglycidyl isocyanurate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide (TPO, Tianjin Jiuri New Materials), 21.0g of silica (D50 2.5μm, D100 4.8μm, solid, commercially available), and 9.0g of mica powder (BT-30, D50...). 3.3μm, D100 8.0μm, thickness 0.5μm (Chuzhou Wanjuan New Material Co., Ltd.)

[0179] Example 26

[0180] This embodiment 26 provides a photosensitive dry film with excellent chemical resistance; the dry film thickness is 40μm, filler I is selected as spherical silica with a median particle size D50 of 5.0μm and a maximum particle size D100 of 7.5μm; filler II is selected as flake mica powder with a median particle size D50 of 3.3μm, a maximum particle size D100 of 8.0μm, and a thickness of 0.5μm;

[0181] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 12.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 12.0g of tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 15.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 15.0g of triglycidyl isocyanate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide (TPO, Tianjin Jiuri New Materials), 6.0g of silica (D50 5.0μm, D100 7.5μm, solid, commercially available), and 6.0g of mica powder (BT-30, D50...). 3.3μm, D100 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Material Co., Ltd.), 1.5g antioxidant 1010 (BASF).

[0182] Example 27

[0183] This embodiment 27 provides a photosensitive dry film with excellent chemical resistance; the dry film thickness is 40 μm, filler I is selected as spherical silica with a median particle size D50 of 5.0 μm and a maximum particle size D100 of 7.5 μm; filler II is selected as flake mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 0.5 μm;

[0184] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 12.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 12.0g of tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 15.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 15.0g of triglycidyl isocyanate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide (TPO, Tianjin Jiuri New Materials), 43.0g of silica (D50 5.0μm, D100 7.5μm, solid, commercially available), and 5.0g of mica powder (BT-30, D50...). 3.3μm, D100 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Material Co., Ltd.), 1.5g antioxidant 1010 (BASF).

[0185] Comparative Example 1

[0186] Comparative Example 1 provides a photosensitive dry film with a thickness of 20 μm. The filler I is selected as spherical silica with a median particle size D50 of 5.0 μm and a maximum particle size D100 of 7.5 μm.

[0187] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solid content 65.3%, Nippon Kayaku), 12.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 12.0g of tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 15.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemicals, Japan), 15.0g of triglycidyl isocyanate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), and 30.0g of silica (D50 5.0μm, D100 7.5μm, solid, commercially available).

[0188] Comparative Example 2

[0189] Comparative Example 2 provides a photosensitive dry film with a thickness of 20 μm.

[0190] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 12.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 12.0g of tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 15.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 15.0g of triglycidyl isocyanate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), and 13.5g of mica powder (BT-30, D50 3.3μm, D100 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Materials Co., Ltd.).

[0191] Comparative Example 3

[0192] Comparative Example 3 provides a photosensitive dry film with a thickness of 20 μm.

[0193] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 12.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 12.0g of tris(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 15.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemicals, Japan), 15.0g of triglycidyl isocyanurate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), and 1.5g of antioxidant 1010 (BASF).

[0194] Comparative Example 4

[0195] Comparative Example 4 provides a photosensitive dry film with a thickness of 20 μm.

[0196] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 12.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 12.0g of tris(2-hydroxyethyl) isocyanurate triacrylate (THEICTA, Sartoma), 15.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 15.0g of triglycidyl isocyanurate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), and 13.5g of mica powder (BT-30, D50 3.3μm, D100). 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Material Co., Ltd.), 1.5g antioxidant 1010 (BASF).

[0197] Comparative Example 5

[0198] Comparative Example 5 provides a photosensitive dry film; the dry film thickness is 20 μm, filler 1 is spherical silica with a median particle size D50 of 3.6 μm and a maximum particle size D100 of 9.8 μm; filler II is flake mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 0.5 μm;

[0199] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 20.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 20.0g of biphenyl crystalline epoxy resin (YX-4000, Mitsubishi Chemical, Japan), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), 21.0g of silica (D50 3.6μm, D100 9.8μm, Lianrui New Materials), 9.0g of mica powder (BT-30, D50 3.3μm, D100 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Materials Co., Ltd.), and 1.5g of antioxidant 1010 (BASF).

[0200] Comparative Example 6

[0201] Comparative Example 6 provides a photosensitive dry film; the dry film thickness is 40 μm, filler I is spherical silica with a median particle size D50 of 2.5 μm and a maximum particle size D100 of 4.8 μm; filler II is flake-shaped mica powder with a median particle size D50 of 3.3 μm, a maximum particle size D100 of 8.0 μm, and a thickness of 0.5 μm;

[0202] The resin composition comprises: 100.0g of alkali-soluble vinyl resin CCR-4959 (acid value: 75.7mgKOH / g, solids content 65.3%, Nippon Kayaku), 20.0g of dipentaerythritol hexaacrylate (DPHA, Sartoma), 20.0g of triglycidyl isocyanate (TGIC, Nissan Chemical), 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO, Tianjin Jiuri New Materials), 21.0g of silica (D50 2.5μm, D100 4.8μm, solid, commercially available), 9.0g of mica powder (BT-30, D50 3.3μm, D100 8.0μm, thickness 0.5μm, Chuzhou Wanjuan New Materials Co., Ltd.), and 1.5g of antioxidant 1010 (BASF).

[0203] The resin composition formulations of Examples 1-27 and Comparative Examples 1-6 are shown in Table 1; slurries were prepared according to the following method:

[0204] Step S1: Mix the solvent and dispersant and place them in a high-power ultrasonic device. Slowly add the required filler 1 and filler 2 under ultrasonic conditions. After all the filler is added, continue ultrasonication for 2 hours.

[0205] Step S2: First, add the resin to a mechanical high-speed dispersion device and stir for 2 hours, keeping the device temperature constant at 40℃. At this temperature, the resin viscosity is low. Then, slowly add the filler pre-dispersion liquid obtained from the first step of ultrasonic dispersion under medium-speed stirring. Continue stirring at medium speed for 2 hours, and then stir with a high-speed sand mill to finally obtain a fine slurry.

[0206] The slurry is coated onto a copper plate and then subjected to photocuring and thermal curing to obtain a solder resist insulating cured film. The Stouffer exposure scale reaches 9 to 11 / 21 levels, the thermal curing temperature is 150 to 180℃, and the time is 60 to 90 minutes.

[0207] The chemical resistance of the photosensitive dry films or cured films prepared in Examples 1-27 and Comparative Examples 1-6 was tested by the following methods, wherein methods (1), (2), (3), and (5) were used to test the performance of the cured film, and method (4) was used to test the performance of the uncured photosensitive dry film. The test results are shown in Table 2.

[0208] (1) Acid resistance: First, immerse the cured film in 25℃ 10wt% H2SO4 or 25℃ 10vol% HCl aqueous solution for 30 minutes. After immersion, wipe the water stains on the surface of the film with a lint-free cloth, score the film surface with a cross-cutting tool, and then pull up 3M 600 tape vertically at 90° to see if it falls off. The adhesion should not be less than 5B.

[0209] (2) Nickel-gold adhesion: The cured film is subjected to nickel-gold surface treatment [degreasing → water washing → micro etching → water washing → acid washing → pre-immersion → activated nickel → water washing → post-immersion → water washing → nickel immersion → water washing → gold immersion → drying]. Then, use a cross-cutting tool to make a grid on the surface of the dried film after nickel-gold surface treatment. Then, use 3M 600 tape to pull it vertically at 90° to see if it falls off. The adhesion should not be less than 5B.

[0210] (3) Nickel-palladium-gold properties: The cured film is subjected to nickel-gold surface treatment [degreasing → water washing → micro-etching → water washing → acid washing → pre-immersion → activated nickel → water washing → post-immersion → water washing → nickel immersion → water washing → target immersion → water washing → gold immersion → water washing → drying].

[0211] (4) Lateral etching: The photosensitive dry film was made into a circuit pattern using film with line width / line spacing of 50μm / 50μm respectively; the circuit pattern was sliced, and the cross section was observed with a metallographic microscope to obtain the size of the lateral etching and record the data.

[0212] (5) PCT: Pressure cooker cooking, temperature 121℃, humidity 100%, pressure 0.2MPa, cooking time 48h, 96h and 120h respectively. After the test, observe and record the appearance. If there is any cracking or blistering, if there is no such problem, perform the 100-grain adhesion test. The evaluation criteria for passing the PCT test is: the appearance of the solder resist film layer is free of cracking or blistering and the adhesion is not less than 5B at the corresponding test time.

[0213] ◎: No cracks or bubbles on the surface; ○: Bubbles on the surface but no cracks; ×: Cracks on the surface or cracks and bubbles on the surface.

[0214] Table 1 Formulations of photosensitive dry film and photosensitive resin compositions in Examples 1-27 and Comparative Examples 1-6

[0215]

[0216]

[0217] Table 2. Results of chemical resistance tests for Examples 1-27 and Comparative Examples 1-6

[0218]

[0219]

[0220] As shown in Table 1, the photosensitive dry films of Examples 1-27 of this application can mostly achieve a level of 4B-5B in terms of acid resistance, nickel-gold resistance, and nickel-palladium-gold resistance, with a maximum PCT (Probability Time) of 120 hours. The photosensitive dry films of Comparative Examples 1-6 have a chemical resistance of 1-3B, with most having a PCT of 48 hours or less. Clearly, the overall chemical resistance of the photosensitive dry films of Examples 1-27 is better than that of the photosensitive dry films of Comparative Examples 1-6.

[0221] By comparing the acid resistance, chemical resistance, nickel-gold adhesion, nickel-palladium-gold adhesion, and side-etching performance of the photosensitive dry films of Examples 1-27 and Comparative Examples 1-6, it can be seen that the ratio of the dry film thickness of 20μm / 40μm to the median particle size D50 of the filler in Examples 1-27 is in the range of (4-8):1, and the ratio of the dry film thickness of 20μm / 40μm to the maximum particle size D100 of the inorganic filler is above 2.8, which can significantly improve the chemical resistance of the photosensitive dry film of the solder resist layer.

[0222] This application extends the time it takes for acidic small molecules to reach the dry film and copper interface by obstructing and / or prolonging the permeation and diffusion path. Within the same timeframe, the acidic small molecules exhibit lower or almost no etching of copper oxide at the dry film and copper interface, thus improving the chemical resistance of the dry film. Furthermore, increasing the amount of antioxidant in the dry film resin composition enhances its chemical resistance. The further addition of filler II, combined with the synergistic effect of filler I, filler II, and the antioxidant, significantly improves the overall chemical resistance and reliability of the photosensitive dry film.

[0223] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A photosensitive dry film, characterized in that, The photosensitive dry film includes a base film and inorganic fillers distributed in the base film; wherein, the ratio of the thickness of the photosensitive dry film to the median particle size D50 of the inorganic filler is (4~8):1, and the ratio of the thickness of the photosensitive dry film to the maximum particle size D100 of the inorganic filler is greater than 2.8; the thickness of the photosensitive dry film is less than or equal to 100μm.

2. The photosensitive dry film according to claim 1, characterized in that, The ratio of the thickness of the photosensitive dry film to the median particle size D50 of the inorganic filler is (5~8):1; And / or, the ratio of the thickness of the photosensitive dry film to the maximum particle size D100 of the inorganic filler is greater than or equal to 4.

3. The photosensitive dry film according to claim 1, characterized in that, The ratio of the thickness of the photosensitive dry film to the maximum particle size D100 of the inorganic filler is 4 to 7.

4. The photosensitive dry film according to claim 1, characterized in that, The thickness of the photosensitive dry film is 10~50μm; And / or, the median particle size D50 of the inorganic filler is 2.5~8.0μm, and the maximum particle size D100 is less than or equal to 10μm.

5. The photosensitive dry film according to claim 1, characterized in that, The thickness of the photosensitive dry film is 15~40μm.

6. The photosensitive dry film according to claim 1, characterized in that, The thickness of the photosensitive dry film is 20~40μm.

7. The photosensitive dry film according to any one of claims 1 to 4, characterized in that, The inorganic filler includes inorganic filler I; wherein, inorganic filler I is selected from at least one of titanium dioxide, barium sulfate, silicon dioxide and aluminum hydroxide; And / or, the raw material of the base film includes an alkali-soluble vinyl resin.

8. The photosensitive dry film according to claim 7, characterized in that, The median particle size D50 of the inorganic filler I is 2.5~8.0μm, and the maximum particle size D100 is less than or equal to 10μm.

9. The photosensitive dry film according to claim 7, characterized in that, The inorganic filler also includes inorganic filler II; wherein, inorganic filler II is flaky mica powder and / or flaky talc powder.

10. The photosensitive dry film according to claim 9, characterized in that, The median particle size D50 of the inorganic filler II is 1~10μm, and the maximum particle size D100 is less than or equal to 15μm.

11. The photosensitive dry film according to claim 9, characterized in that, The median particle size D50 of the inorganic filler II is 3~7μm, and the maximum particle size D100 is less than or equal to 10μm.

12. The photosensitive dry film according to claim 9, characterized in that, The median particle size D50 of the inorganic filler II is 3~7μm, and the maximum particle size D100 is 5~10μm.

13. The photosensitive dry film according to claim 9, characterized in that, The thickness of the inorganic filler II is less than or equal to 1.5 μm.

14. The photosensitive dry film according to claim 9, characterized in that, The thickness of the inorganic filler II is 0.5~1.0μm.

15. The photosensitive dry film according to claim 9, characterized in that, The inorganic filler II is distributed in the base membrane substantially parallel to the surface of the base membrane.

16. The photosensitive dry film according to claim 7, characterized in that, The alkali-soluble vinyl resin is selected from at least one of carboxylic acid-modified bisphenol A type epoxy vinyl resin, carboxylic acid-modified bisphenol F type epoxy vinyl resin, carboxylic acid-modified bisphenol S type epoxy vinyl resin, and carboxylic acid-modified phenolic epoxy vinyl resin.

17. The photosensitive dry film according to claim 1, characterized in that, The photosensitive dry film is prepared from a resin composition, the raw materials of which include the following components in parts by weight: 100 parts of alkali-soluble vinyl resin, 10-30 parts of reactive diluent, 20-40 parts of thermosetting agent, 0.1-5 parts of photoinitiator, 15-45 parts of the inorganic filler, and 0.1-3 parts of antioxidant.

18. The photosensitive dry film according to claim 17, characterized in that, The morphology of the inorganic filler I includes at least one of amorphous, angular, and spherical shapes.

19. The photosensitive dry film according to claim 17, characterized in that, The inorganic packing I is a solid packing and / or a hollow packing.

20. The photosensitive dry film according to claim 19, characterized in that, The inorganic packing I is a solid packing.

21. The photosensitive dry film according to claim 9, characterized in that, The weight ratio of inorganic filler I to inorganic filler II is (11~17):(3~9).

22. The photosensitive dry film according to claim 21, characterized in that, The inorganic filler I and / or the inorganic filler II are surface modified with a modifying compound; wherein the modifying compound is an epoxy compound or an acrylic compound.

23. The photosensitive dry film according to claim 17, characterized in that, The reactive diluent is selected from at least one of monofunctional reactive diluents, difunctional reactive diluents, trifunctional reactive diluents, and highly functional reactive diluents. And / or, the thermosetting agent comprises at least one of the following: a terminated isocyanate compound, an amino resin, a benzoxazine resin, a carbodiimide resin, a maleimide compound, a cyclic carbonate compound, an epoxy compound, a polyfunctional oxobutane compound, and an cyclic sulfur resin.

24. The photosensitive dry film according to claim 17, characterized in that, The acid value of the alkali-soluble vinyl resin is 45~120 mg KOH / g.

25. The photosensitive dry film according to claim 24, characterized in that, The acid value of the alkali-soluble vinyl resin is 80~100 mg KOH / g.

26. The photosensitive dry film according to claim 23, characterized in that, The monofunctional reactive diluent is selected from aromatic (meth)acrylates, alkoxy-dodecyl (meth)acrylates, alicyclic (meth)acrylates, 2(2-ethoxyethoxy)ethyl acrylates, octadecyl (meth)acrylates, tetrahydrofuran (meth)acrylates, dodecyl (meth)acrylates, 2-phenoxyethyl (meth)acrylates, isodecanyl (meth)acrylates, alicyclic (meth)acrylates, octyl (meth)acrylates, isooctyl (meth)acrylates, tridecyl (meth)acrylates, caprolactone (meth)acrylates, (4) ethoxylated nonylphenol (meth)acrylates. At least one of the following: acrylate, isobornyl acrylate, trimethylolpropane formal (meth)acrylate, methoxy polyethylene glycol mono(meth)acrylate, methoxy polyethylene glycol (500) mono(meth)acrylate, alkoxylated tetrahydrofuran (meth)acrylate, alkoxylated nonylphenol (meth)acrylate, dimethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 4-hydroxybutyl vinyl ether, glyceryl carbonate propylene ether, and dodecyl vinyl ether.

27. The photosensitive dry film according to claim 23, characterized in that, The bifunctional reactive diluent is selected from cyclohexanediol di(meth)acrylate, hexanediol di(meth)acrylate alkyl oxidase, neopentyl glycol di(meth)acrylate alkyl oxidase, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol (200) di(meth)acrylate, triethylene glycol di(meth)vinyl ether, tetraethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and 1,4-cyclohexyldiethanol di(meth)acrylate. At least one of the following: (meth)alkenyl ether, ethylene glycol di(meth)acrylate, pentylene glycol di(meth)acrylate, polyethylene glycol (400) di(meth)acrylate, polyethylene glycol (600) di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A di(meth)acrylate, dipropylene glycol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, and propoxylated neopentyl glycol di(meth)acrylate.

28. The photosensitive dry film according to claim 23, characterized in that, The trifunctional reactive diluent is selected from at least one of the following: tri(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, etc.

29. The photosensitive dry film according to claim 23, characterized in that, The highly functionalized reactive diluent is selected from at least one of di-trimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

30. The photosensitive dry film according to claim 23, characterized in that, The epoxy compound is selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy resin, brominated epoxy resin, hydroquinone type epoxy resin, biphenyl type crystalline epoxy resin, naphthalene type epoxy resin, thioether type epoxy resin, o-cresol varnish type epoxy resin, biphenyl phenolic varnish type epoxy resin, trihydroxyphenyl The epoxy resin is selected from at least one of the following: methane-type epoxy resin, biphenol-type epoxy resin, bisphenol A phenolic varnish-type epoxy resin, tetramethylolpropane-type epoxy resin, heterocyclic epoxy resin, diglycidyl phthalate resin, tetraglycidyl dimethylformyl ethane resin, dicyclopentadiene skeleton glycidyl methacrylate copolymer epoxy resin, cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resin, epoxy-modified polybutadiene rubber derivatives, and CTBN-modified epoxy resin.

31. The photosensitive dry film according to claim 23, characterized in that, The epoxy equivalent of the epoxy compound is 100~400 g / eq.

32. The photosensitive dry film according to claim 23, characterized in that, The polyfunctional oxetane compound is selected from at least one of bis[(3-methyl-3-oxetane-butylmethoxy)methyl] ether, bis[(3-ethyl-3-oxetane-butylmethoxy)methyl] ether, 1,4-bis[(3-methyl-3-oxetane-butylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetane-butylmethoxy)methyl]benzene, (3-methyl-3-oxetane-butyl)methyl acrylate, (3-ethyl-3-oxetane-butyl) methacrylate, (3-methyl-3-oxetane-butyl) methyl methacrylate, (3-ethyl-3-oxetane-butyl) methyl methacrylate and their oligomers or copolymers, oxetane alcohol, phenolic varnish resin, poly(p-hydroxystyrene), Cardo type bisphenol, calixarene, and calix-isophenylene diarylene.

33. The photosensitive dry film according to claim 23, characterized in that, The amino resin is selected from at least one of hydroxymethyl melamine compound, hydroxymethyl benzoguanamine compound, hydroxymethyl glycourea compound, and hydroxymethyl urea compound.

34. The photosensitive dry film according to claim 17, characterized in that, The photoinitiators include pyrolytic radical polymerization photoinitiators, hydrogen-abstracting radical polymerization photoinitiators, and cationic polymerization photoinitiators; And / or, the antioxidant includes antioxidant I; wherein, antioxidant I includes aromatic amine compounds and / or hindered phenolic compounds.

35. The photosensitive dry film according to claim 34, characterized in that, The cleavage-type free radical polymerization photoinitiator is selected from at least one of α-hydroxy ketone derivatives, α-amino ketone derivatives, acylphosphine oxides, and oxime esters.

36. The photosensitive dry film according to claim 35, characterized in that, The α-hydroxy ketone derivatives are selected from at least one of 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 1-[4-(2-hydroxy)-phenyl]-3-hydroxy-2-methyl-1-propanone-1-one.

37. The photosensitive dry film according to claim 35, characterized in that, The α-amino ketone derivatives are selected from at least one of 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinylbenzylphenyl)butanone, and 2-p-methylbenzyl-2-dimethylamino-1-(4-morpholinylphenyl)-1-butanone.

38. The photosensitive dry film according to claim 35, characterized in that, The acylphosphine oxide is selected from at least one of 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

39. The photosensitive dry film according to claim 35, characterized in that, The oxime esters are 1,8-bis[9-ethyl-6-nitro-9H-carbazole-3-yl]-,1,8-bis(O-acetyl oxime) and / or 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime).

40. The photosensitive dry film according to claim 34, characterized in that, The hydrogen-abstracting free radical initiator is selected from at least one of benzophenone and its derivatives, thioxanthone and its derivatives, anthraquinone and its derivatives, and diacetic titanium compounds.

41. The photosensitive dry film according to claim 40, characterized in that, The thioxanthonone is selected from at least one of 2,4-diethylthioxanthonone, isopropylthioxanthonone, and 1-chloro-4-propoxythioxanthonone.

42. The photosensitive dry film according to claim 40, characterized in that, The titanium diacene group is selected from at least one of 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.

43. The photosensitive dry film according to claim 34, characterized in that, The cationic polymerization photoinitiator is selected from at least one of aryl diazonium salts, diaryl iodonium salts, triaryl thiodonium salts, aryl ferrocene salts, and isopropylbenzene ferrocene hexafluorophosphate.

44. The photosensitive dry film according to claim 43, characterized in that, The cationic polymerization photoinitiator is selected from at least one of dodecylbenzeneiodonium salt, long-chain alkoxydiphenyliodonium salt, phenylthiophenyldiphenylthionium salt, diphenylthionium hexafluoroantimonate, UV16976, UV16992 and UV261.

45. The photosensitive dry film according to claim 34, characterized in that, The antioxidant I is selected from at least one of 2-tert-butylhydroquinone, hydroquinone monomethyl ether, pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylate, 2,6-di-tert-butyl-p-cresol, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, p-methoxyphenol, and phenothiazines.

46. ​​The photosensitive dry film according to claim 34, characterized in that, The antioxidant also includes antioxidant II; wherein antioxidant II is a phosphorus-containing organic compound and / or a sulfur-containing organic compound.

47. The photosensitive dry film according to claim 46, characterized in that, The antioxidant II is selected from at least one of triphenyl phosphite, pentaerythritol tetra(lauryl thioacrylate), and dilauryl thiodipropionate.

48. A cured film, characterized in that, The cured film is obtained by sequentially photocuring and thermal curing a photosensitive dry film; wherein the photosensitive dry film is the photosensitive dry film according to any one of claims 1 to 47.

49. A printed circuit board, characterized in that, The printed circuit board includes a copper plate and a cured film attached to the surface of the copper plate; wherein the cured film is the cured film according to claim 48.

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