Resin composition, photosensitive resin film, and application thereof

Abstract

This invention provides a resin composition, a photosensitive resin film, and their applications. The resin composition comprises, by weight, 30-60 parts of a photosensitive polymer, 10-30 parts of an epoxy resin, 5-20 parts of an acrylate monomer, 0.5-5 parts of a photoinitiator, 0.05-1 parts of a thermosetting accelerator, and 10-40 parts of a filler. The photoinitiator comprises a combination of 2-dimethylamino-2-(4-methyl)benzyl-1-(4-(4-morpholino)phenyl)-1-butanone, a phosphorus oxide photoinitiator, and an oxime ester photoinitiator, wherein the oxime ester photoinitiator comprises 5-30% by weight. Through the design of a specific photoinitiator and its compounding with other components, the formed photosensitive resin film exhibits high peel strength, high photosensitivity resolution, and, most importantly, high adhesion between the photosensitive resin film and the substrate, resulting in excellent fine-line reliability.

Description

Technical Field

[0001] This invention belongs to the field of printed circuit board technology, specifically relating to a resin composition, a photosensitive resin film, and their applications. Background Technology

[0002] The main design trends for electronic information products are thinness, lightness, miniaturization, and multifunctionality. With the iterative development of electronic information products, printed circuit boards (PCBs), as the main support for electronic components, also need to continuously improve their technology to provide high-density wiring, thinness, micro-aperture, and multi-dimensional performance. Since the substrate material largely determines the performance of the PCB, there is an urgent need to develop a new generation of substrate materials.

[0003] Compared to prepregs, resin films or resin-coated copper foils without reinforcement can achieve thinner profiles, higher-density wiring, micro-pore sizes, and multi-dimensional molding, making them a promising next-generation matrix material. Traditional insulating films primarily use laser drilling to create interconnecting holes, while photosensitive films can achieve photo-induced hole formation, which is not only more efficient than laser drilling but also allows for smaller pore sizes, enabling applications in higher-end fine-line wiring. For example, CN110895381A discloses a photosensitive solder resist ink composition comprising: (A) a photosensitive resin containing a carboxyl group and at least two olefinic unsaturated bonds in its molecule, and the following components based on 100 parts by weight of the photosensitive resin: (B) 1-40 parts by weight of a photoinitiator, (C) 0.1-20 parts by weight of an organic surface additive, (D) 2-200 parts by weight of a diluent, (E) 3-100 parts by weight of a thermosetting component, (F) 1-50 parts by weight of a photopolymerizable monomer, and (G) 20-150 parts by weight of an inorganic filler; when the cured film formed by the above photosensitive solder resist ink composition is used on a printed circuit board, it has good reliability without reducing other properties of the ink. CN111978785A discloses a photosensitive solder resist ink, comprising the following components: 35-60 parts of photosensitive resin, 5-15 parts of flexible resin, 5-10 parts of reactive diluent, 5-10 parts of photoinitiator, 0.1-10 parts of filler, 0.1-10 parts of pigment, 0.1-5 parts of additives, and 10-40 parts of organic solvent; wherein the flexible resin is a bisphenol A type epoxy resin modified with glycol or diacid; the ink has a fast curing speed, good film-forming properties, and good mechanical and anti-corrosion properties, and can be used in flexible printed circuit boards.

[0004] To meet heat resistance requirements, inorganic fillers are typically added to photosensitive insulating films to improve their heat resistance, dimensional stability, and chemical resistance. However, the introduction of inorganic fillers negatively impacts the film's toughness and peel strength, particularly affecting the adhesion between the photosensitive film and the substrate. Therefore, improving the adhesion between the photosensitive film and the substrate while maintaining high photosensitive resolution is a pressing problem in this field. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a resin composition, a photosensitive resin film and its application. By designing a specific photoinitiator and combining it with other components, the photosensitive resin film formed by the resin composition has high peel strength and high photosensitive resolution. In particular, it makes the photosensitive resin film have high adhesion to the substrate, which greatly improves the reliability of fine lines.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a resin composition comprising, by weight, the following components:

[0008]

[0009] The photoinitiator includes a combination of 2-dimethylamino-2-(4-methyl)benzyl-1-(4-(4-morpholino)phenyl)-1-butanone (photoinitiator 379), phosphorus oxide photoinitiators, and oxime ester photoinitiators, wherein the mass percentage of oxime ester photoinitiators in the photoinitiator is 5-30%.

[0010] The phosphorus oxide photoinitiator is selected from any one or a combination of at least two of the following: ethyl 2,4,6-trimethylbenzoylphenylphosphonate (photoinitiator TPO-L), (2,4,6-trimethylbenzoyl)bis(p-tolyl)phosphine oxide (photoinitiator TMO), and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (photoinitiator 819).

[0011] In the resin composition provided by the present invention, the photoinitiator adopts a ternary compound system of a specific ketone photoinitiator (photoinitiator 379), a specific oxidized phosphorus photoinitiator, and an oxime ester photoinitiator. Through the design of the ternary system and the synergistic effect between the components, and compounded with photosensitive polymers, epoxy resins, acrylate monomers, thermosetting accelerators, and fillers, the photosensitive resin film made from the resin composition has high peel strength and high photosensitivity resolution. In particular, it greatly improves the adhesion between the photosensitive resin film and the substrate, thus greatly enhancing the reliability of the printed circuit board.

[0012] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0013] The photosensitive polymer is in the range of 30-60 parts by weight, for example, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts or 58 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0014] The epoxy resin is in the range of 10-30 parts by weight, for example, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts or 28 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0015] The acrylate monomers are in the range of 5-20 parts by weight, for example, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 15 parts, 16 parts or 18 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0016] The photoinitiator is 0.5-5 parts by mass, for example, it can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts or 4.5 parts, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0017] The thermosetting accelerator is 0.05-1 parts by weight, for example, it can be 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts or 0.9 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0018] The filler is in the range of 10-40 parts by weight, for example, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts or 38 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0019] The terms "parts" and "parts by weight" used in this invention are calculated based on solid content and do not include solvents, dispersants, etc.

[0020] The oxime ester photoinitiator in the photoinitiator has a mass percentage of 5-30%, for example, it can be 6%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25% or 28%, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0021] In this invention, the oxime ester photoinitiator comprises 5-30% by mass. It forms a complex photoinitiation system with 2-dimethylamino-2-(4-methyl)benzyl-1-(4-(4-morpholino)phenyl)-1-butanone and a specific phosphorus oxide photoinitiator. This system works synergistically with other components to give the photosensitive resin film formed by the resin composition high photosensitivity and high peel strength, particularly high adhesion between the photosensitive resin film and the substrate. If the oxime ester photoinitiator is absent or used in insufficient quantities, the peel strength of the photosensitive resin film will decrease, and the adhesion to the substrate will weaken. Conversely, if the amount of the oxime ester photoinitiator is too high, the photosensitivity of the photosensitive resin film will decrease, and the amount of residual resin after development will increase.

[0022] Preferably, the mass ratio of 2-dimethylamino-2-(4-methyl)benzyl-1-(4-(4-morpholinyl)phenyl)-1-butanone to the phosphorus oxide photoinitiator is 1:(1-5), for example, it can be 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5, 1:3.8, 1:4, 1:4.2, 1:4.5 or 1:4.8, etc.

[0023] As a preferred embodiment of the present invention, the mass ratio of 2-dimethylamino-2-(4-methyl)benzyl-1-(4-(4-morpholino)phenyl)-1-butanone to phosphorus oxide photoinitiator is 1:(1-5), more preferably 1:(1-3). This forms a ternary composite photoinitiator system with the oxime ester photoinitiator, enabling the photosensitive resin film made from the resin composition to possess excellent exposure performance, high photosensitivity resolution, high peel strength, and excellent adhesion. If the amount of phosphorus oxide photoinitiator is too low, the exposure performance will be poor, and circuit detachment may easily occur; if the amount of phosphorus oxide photoinitiator is too high, the photosensitivity resolution will decrease.

[0024] Preferably, the oxime ester photoinitiator includes 1-(9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl)-ethyl ketone 1-(O-acetyl oxime) (photoinitiator OXE02) and / or 1-(4-(phenylthio)phenyl)-1,2-octanedione 2-(O-benzoyl oxime) (photoinitiator OXE01).

[0025] Preferably, the photosensitive polymer comprises a carboxyl polymer containing unsaturated bonds.

[0026] In this invention, the molecular structure of the photosensitive polymer contains C=C unsaturated bonds and carboxyl groups. The C=C unsaturated bonds endow it with the activity of photocuring reaction, and the carboxyl groups make it alkali-soluble, enabling it to be developed in alkaline developer and form circuit patterns.

[0027] Preferably, the acid value of the photosensitive polymer is 20-200 mg KOH / g, for example, it can be 30 mg KOH / g, 40 mg KOH / g, 50 mg KOH / g, 60 mg KOH / g, 80 mg KOH / g, 100 mg KOH / g, 120 mg KOH / g, 150 mg KOH / g or 180 mg KOH / g, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0028] For example, the acid value of the photosensitive polymer can be obtained by titration.

[0029] Preferably, the photosensitive polymer is prepared by reacting epoxy resin with (meth)acrylic acid monomer and then with acid anhydride.

[0030] For example, the photosensitive polymer is prepared by a method comprising: reacting an epoxy resin with a (meth)acrylic acid monomer in a first reaction, and reacting the resulting product with an acid anhydride in a second reaction to obtain the photosensitive polymer.

[0031] Preferably, the epoxy resin used to prepare the photosensitive polymer includes any one or a combination of at least two of the following: bisphenol A type epoxy resin, bisphenol S type epoxy resin, phenolic epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene-containing epoxy resin, and alicyclic epoxy resin.

[0032] In this invention, the (meth)acrylic acid monomer includes acrylic acid and / or methacrylic acid.

[0033] Preferably, the anhydride comprises any one or a combination of at least two of tetrahydrophthalic anhydride, phthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, maleic anhydride, and nadic anhydride.

[0034] Preferably, in the preparation of the photosensitive polymer, based on 100 parts by weight of the epoxy resin, the mass of the (meth)acrylic acid monomer is 10-50 parts, for example, 15 parts, 20 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, or 45 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0035] Preferably, in the preparation of the photosensitive polymer, based on 100 parts by weight of the epoxy resin, the mass of the acid anhydride is 20-80 parts, for example, 25 parts, 30 parts, 35 parts, 38 parts, 40 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts, 58 parts, 60 parts, 65 parts, 70 parts, or 75 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0036] Preferably, the first reaction is carried out in the presence of a catalyst.

[0037] Preferably, the catalyst comprises any one or a combination of at least two of dimethylbenzylamine, tetraethylammonium bromide, tetrabutylammonium bromide, and triphenylphosphine.

[0038] Preferably, in the preparation of the photosensitive polymer, based on 100 parts by weight of the epoxy resin, the mass of the catalyst is 0.1-1 parts, for example, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, or 0.9 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0039] Preferably, the temperatures of the first reaction and the second reaction are each independently 80-120°C, for example, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C or 115°C, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0040] Preferably, the time for the first reaction and the second reaction is independently 2-10 hours, for example, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours or 9.5 hours, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0041] Preferably, the epoxy resin in the resin composition includes any one or a combination of at least two of the following: bisphenol A type epoxy resin, phosphorus-containing epoxy resin, isocyanate-modified epoxy resin, phenolic epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene-containing epoxy resin, and alicyclic epoxy resin.

[0042] Preferably, the isocyanate-modified epoxy resin includes MDI-modified epoxy resin.

[0043] Preferably, the acrylate monomers include difunctional acrylate monomers and / or polyfunctional acrylate monomers.

[0044] In this invention, the bifunctional acrylate monomer means that 1 mol of monomer contains 2 mol of C=C unsaturated bonds; the polyfunctional acrylate monomer means that 1 mol of monomer contains ≥3 mol of C=C unsaturated bonds.

[0045] Preferably, the acrylate monomers include any one or a combination of at least two of the following: 1,6-hexanediol diacrylate, pentaerythritol pent- / hex-acrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol pentaacrylate, and pentaerythritol hexaacrylate.

[0046] Preferably, the thermosetting accelerator comprises imidazole compounds, and more preferably any one or a combination of at least two of 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, and 1-cyanoethyl-2-methylimidazole.

[0047] Preferably, the packing material is an inorganic packing material and / or an organic packing material, and more preferably an inorganic packing material.

[0048] Preferably, the inorganic filler comprises any one or a combination of at least two of the following: non-metallic oxides, metal oxides, metal hydroxides, metal nitrides, non-metallic nitrides, inorganic hydrates, inorganic salts, metal hydrates, and inorganic phosphorus.

[0049] Preferably, the inorganic filler includes any one or a combination of at least two of the following: silicon dioxide, aluminum hydroxide, aluminum oxide, talc, aluminum nitride, boron nitride, silicon carbide, barium sulfate, barium titanate, strontium titanate, calcium carbonate, calcium silicate, and mica.

[0050] Preferably, the silicon dioxide includes any one or a combination of at least two of molten silicon dioxide, crystalline silicon dioxide, spherical silicon dioxide, and hollow silicon dioxide, with spherical silicon dioxide being more preferred.

[0051] Preferably, the organic filler includes any one or a combination of at least two of the following: polyphenylene ether filler, polytetrafluoroethylene filler, polyether ether ketone filler, polyphenylene sulfide filler, and polyether sulfone filler.

[0052] Preferably, the median particle size (D) of the filler is... 50 The particle size is 0.01-1μm, for example, it can be 0.05μm, 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm or 0.9μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0053] Preferably, the filler comprises a surface-treated filler.

[0054] Preferably, the surface treatment agent for the surface treatment includes any one or a combination of at least two of silane coupling agents, organosilicon oligomers, and titanate coupling agents.

[0055] Preferably, based on 100 parts of the filler to be treated, the mass of the surface treatment agent is 0.1-5 parts, for example, 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, or 5 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range. More preferably, it is 0.5-3 parts, and even more preferably, it is 0.75-2 parts.

[0056] For example, the particle size of the filler was obtained using an MS3000 Malvern laser particle size analyzer.

[0057] As a preferred embodiment of the present invention, the resin composition further includes pigments. The components of the pigments can be selected according to the color required when masking wiring, etc., that is, pigments that display the desired color can be appropriately selected and used. For example, the pigments include any one or a combination of at least two of phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium dioxide, carbon black, and naphthalene black.

[0058] Preferably, the resin composition further comprises 0.05-2 parts of pigment by weight, for example, 0.08 parts, 0.1 parts, 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts or 1.8 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but 0.05-1 parts is further preferred.

[0059] As a preferred embodiment of the present invention, the resin composition further includes a sensitizer, which includes any one or a combination of at least two of the following: ethyl p-dimethylaminobenzoate (EDB), bisimidazole (BCIM), 4-(4-methylphenylthio)benzophenone (BMS), isooctyl p-dimethylaminobenzoate (EHA), and 4-bis(diethylamino)benzophenone (MEK).

[0060] Preferably, the sensitizer in the resin composition is 0-1 parts by weight, for example, 0.01 parts, 0.05 parts, 0.08 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, or 0.9 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0061] Preferably, the resin composition further comprises 0.05-1 parts by weight of a sensitizer.

[0062] Solvents may also be added to the above-mentioned resin composition. The amount of solvent added is selected by those skilled in the art based on experience and process requirements, so that the resin composition reaches a suitable viscosity for use, facilitating coating and other processes. During subsequent drying, semi-curing, or full curing stages, the solvent in the resin composition will partially or completely evaporate.

[0063] Furthermore, the present invention provides a resin solution obtained by dissolving or dispersing the resin composition described above in a solvent.

[0064] The solvent used in this invention is not particularly limited. Specific examples include alcohols such as methanol, ethanol, and butanol; ethers such as ethyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, carbitol, and butyl carbitol; ketones such as acetone, butanone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and mesitylene; esters such as ethyl acetate, butyl acetate, and ethoxyethyl acetate; and nitrogen-containing solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. The solvent can be used alone or in combination of two or more solvents. Preferably, it is any one or a combination of at least two of toluene, xylene, mesitylene, acetone, butanone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

[0065] The resin composition provided by the present invention is prepared by the following method, the preparation method comprising: mixing and dispersing the components in the resin composition evenly to obtain the resin composition.

[0066] In a second aspect, the present invention provides a photosensitive resin film, the material of which comprises the resin composition as described in the first aspect.

[0067] Preferably, the photosensitive resin film is prepared by coating the resin composition onto a release material and then drying and / or semi-curing it.

[0068] Preferably, the drying and semi-curing temperatures are each independently between 100-180℃, for example, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, or 175℃, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range.

[0069] Preferably, the drying and semi-curing times are each independently 1-30 min, for example, 2 min, 5 min, 8 min, 10 min, 15 min, 20 min or 25 min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 2-10 min is further preferred.

[0070] Preferably, the thickness of the photosensitive resin film is 5-300 μm, for example, it can be 10 μm, 20 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 220 μm, 250 μm or 280 μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range. More preferably, it is 10-200 μm, and more preferably, it is 20-100 μm.

[0071] Preferably, a protective film is further disposed on the photosensitive resin film, and the photosensitive resin film is located between the release material and the protective film.

[0072] As a preferred embodiment of the present invention, the photosensitive resin film is suitable for preparing circuits by a semi-addition method or an addition method.

[0073] Thirdly, the present invention provides a resin-coated copper foil, the resin-coated copper foil comprising a copper foil layer and a resin layer, wherein the material of the resin layer comprises the resin composition as described in the first aspect.

[0074] Preferably, the resin-coated copper foil is obtained by coating the resin composition onto a copper foil and then drying and / or semi-curing it.

[0075] Preferably, the thickness of the resin layer is 5-300 μm, for example, it can be 10 μm, 20 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 220 μm, 250 μm or 280 μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range. More preferably, it is 10-200 μm, and more preferably, it is 20-100 μm.

[0076] Preferably, the thickness of the copper foil is 1-105μm, for example, it can be 5μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm or 102μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range. More preferably, it is 3-35μm, and more preferably, it is 5-18μm.

[0077] Fourthly, the present invention provides a metal foil laminate, the metal foil laminate comprising a photosensitive resin film as described in the second aspect and / or a resin-coated copper foil as described in the third aspect.

[0078] Preferably, the metal foil is copper foil, and the metal foil laminate is copper clad laminate.

[0079] Fifthly, the present invention provides a printed circuit board, the printed circuit board comprising at least one of the following: a photosensitive resin film as described in the second aspect, a resin-coated copper foil as described in the third aspect, and a metal foil laminate as described in the fourth aspect.

[0080] Preferably, the printed circuit board is a multilayer printed circuit board, which includes a photosensitive resin film and a circuit substrate stacked together.

[0081] Preferably, the method for preparing the multilayer printed circuit board includes: stacking and curing a photosensitive resin film and a circuit board (PCB), and then electroplating a metal layer on the side of the photosensitive resin film away from the circuit board to obtain the multilayer printed circuit board.

[0082] Compared with the prior art, the present invention has the following beneficial effects:

[0083] (1) In the resin composition provided by the present invention, through the design and synergistic effect of the photoinitiator and the mutual compounding with other components, the photosensitive resin film formed by the resin composition has high peel strength and high photosensitive resolution, especially the high bonding force between the photosensitive resin film and the substrate, which greatly improves the reliability of the printed circuit board.

[0084] (2) Through the design and optimization of the resin composition, the present invention achieves a bonding force of ≥8N / cm between the photosensitive resin film and the substrate, a photosensitive resolution of 15μm, no developing residue, and a line retention rate of >95% after reflow soldering at 260℃ for 10min. It achieves excellent comprehensive effect in high substrate bonding force and high photosensitive resolution, and has excellent fine line reliability. Detailed Implementation

[0085] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0086] In one specific embodiment, the photosensitive polymer is a carboxyl polymer containing unsaturated bonds, which is prepared by reacting epoxy resin with (meth)acrylic acid monomer and then with acid anhydride.

[0087] The preparation method of the photosensitive polymer is described below with reference to specific preparation examples, but the preparation method of the photosensitive polymer is not limited to these preparation examples.

[0088] Preparation Example 1

[0089] Photosensitive polymer A1 is prepared as follows:

[0090] By weight, 100 parts of phenolic epoxy resin (HEXION, EPR627), 30 parts of acrylic monomer, and 0.5 parts of dimethyl benzylamine were heated at 100°C for 6 hours, then cooled to 80°C, and 50 parts of tetrahydrophthalic anhydride were added. The mixture was then reacted at 85°C for 8 hours and cooled to room temperature to obtain a carboxyl polymer containing unsaturated bonds, i.e., photosensitive polymer A1, with an acid value of 120 mg KOH / g.

[0091] Preparation Example 2

[0092] Photosensitive polymer A2 is prepared as follows:

[0093] By weight, 100 parts of biphenyl epoxy resin (Nippon Kayaku Co., Ltd., NC3000H), 25 parts of acrylic monomer, and 0.4 parts of dimethylbenzylamine were heated at 100°C for 6 hours, then cooled to 80°C, and 45 parts of tetrahydrophthalic anhydride were added. The mixture was then reacted at 85°C for 8 hours and cooled to room temperature to obtain a carboxyl polymer containing unsaturated bonds, i.e., photosensitive polymer A2, with an acid value of 100 mg KOH / g.

[0094] The resin composition, photosensitive resin film and its application described in this invention will be described in detail below with several examples, but the resin composition, photosensitive resin film and its application are not limited to these examples.

[0095] In the following examples, materials for which no preparation method is provided are commercially available chemicals, as detailed in the table below:

[0096]

[0097]

[0098] Examples 1-6, Comparative Examples 1-7

[0099] A resin composition, the types and amounts of each component are shown in Tables 1 and 2, and the unit of amount of each component is "parts" (parts by mass).

[0100] A photosensitive resin film comprising the resin composition and a multilayer printed circuit board are prepared by the following method:

[0101] (1) Mix each component of the resin composition with methyl ethyl ketone according to the above formula amount, stir for 2 hours to prepare a resin solution with a solid content of 65%; coat the resin solution onto the release film, dry it, and bake it in a 120°C oven for 5 minutes to obtain a semi-cured photosensitive resin film with a thickness of 40μm.

[0102] (2) Press and cure the photosensitive resin film obtained in step (1) and the browned PCB board (curing conditions: 180℃, 30min), peel off the release film and perform surface treatment, copper electroplating, to form a multilayer printed circuit board with lines.

[0103] The performance of the resin composition, photosensitive resin film, and multilayer printed circuit board is tested using the following methods:

[0104] (1) Adhesion to the substrate: The adhesion between the resin film and the substrate was tested using the IPC-TM-650 2.4.9 method.

[0105] (2) Photosensitive Resolution: The resin composition was screen-printed onto a 1.6 mm thick full-copper FR-4 substrate with a dry film thickness of 20 μm. It was dried at 80°C for 30 min and then allowed to cool naturally to room temperature. A non-contact exposure device equipped with an ultra-high pressure mercury lamp (5 kW short arc lamp) was used on this substrate. A pattern with a linewidth of 100 μm in the shaded area was exposed at the optimal exposure level. Development was performed in a 1 wt% Na₂CO₃ aqueous solution at 30°C under a spray pressure of 0.2 MPa for 120 s, followed by thermal curing at 150°C for 60 min. This was used as the evaluation sample. The linewidth of the blank in the evaluation sample was measured using an optical microscope.

[0106] (3) Residual resin after development: Observe the residual resin after exposure and development under an optical microscope. If the amount of residual resin is 1%-10%, it is evaluated as "small amount"; if the amount of residual resin is >10%, it is evaluated as "large amount".

[0107] (4) Fine line reliability: After reflow soldering at 260℃ for 10 minutes, the percentage of the area of ​​the multilayer printed circuit board without short circuits is tested. If the percentage is >95%, it is rated as "excellent", 90-95% is rated as "good", and <90% is rated as "poor".

[0108] The performance test data are shown in Tables 1 and 2.

[0109] Table 1

[0110]

[0111]

[0112] Table 2

[0113]

[0114]

[0115] As shown in Table 1, this invention, through the design and synergistic effect of three types of photoinitiators and the compounding with other components, enables the photosensitive resin film formed by the resin composition to have high photosensitive resolution and excellent substrate adhesion. The adhesion between the photosensitive resin film and the substrate is ≥8N / cm, the photosensitive resolution is 15μm, there is no developing residue, and after reflow soldering at 260℃ for 10min, it can maintain a line retention rate of >95%, exhibiting excellent fine line reliability.

[0116] Comparing Tables 1 and 2, it can be seen that Comparative Example 1, lacking an oxime ester photoinitiator, resulted in poor adhesion between the photosensitive resin film and the substrate, mediocre photosensitivity, and reduced circuit reliability. In Comparative Example 2, the proportion of oxime ester photoinitiator in the photoinitiator was too low, and the adhesion between the photosensitive resin film and the substrate still did not meet the requirements, further reducing circuit reliability. In Comparative Example 3, the proportion of oxime ester photoinitiator in the photoinitiator was too high, leading to a decrease in the photosensitivity of the photosensitive resin film, increased residual adhesive after development, and reduced reliability. Comparative Example 4, without photoinitiator 379, exhibited poor photosensitivity and a small amount of residual adhesive after development, resulting in decreased reliability. In Comparative Example 5, replacing photoinitiator 379 with another type of ketone photoinitiator 369 resulted in decreased photosensitivity, adhesion to the substrate, development, residual adhesive, and circuit reliability. Comparative Example 6, without the addition of phosphorus oxide photoinitiators, showed decreased photosensitive resolution, more residual adhesive after development, and poorer adhesion to the substrate, resulting in degraded reliability. Comparative Example 7, with the addition of other types of phosphorus oxide photoinitiators, showed a small amount of residual adhesive after development, and also showed decreased adhesion to the substrate and reduced circuit reliability.

[0117] The applicant declares that the above embodiments illustrate the resin composition, photosensitive resin film, and their applications, but the present invention is not limited to the above embodiments, i.e., it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A resin composition, characterized in that, The resin composition comprises the following components in parts by weight: The photoinitiator comprises a combination of 2-dimethylamino-2-(4-methyl)benzyl-1-(4-(4-morpholino)phenyl)-1-butanone, phosphorus oxide photoinitiators, and oxime ester photoinitiators, wherein the oxime ester photoinitiator comprises 5-30% by mass. The phosphorus oxide photoinitiator is selected from any one or a combination of at least two of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, (2,4,6-trimethylbenzoyl)bis(p-tolyl)phosphine oxide, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

2. The resin composition according to claim 1, characterized in that, The mass ratio of 2-dimethylamino-2-(4-methyl)benzyl-1-(4-(4-morpholinyl)phenyl)-1-butanone to the phosphorus oxidase photoinitiator is 1:(1-5); Preferably, the oxime ester photoinitiator includes 1-(9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl)-ethyl ketone 1-(O-acetyl oxime) and / or 1-(4-(phenylthio)phenyl)-1,2-octanedione 2-(O-benzoyl oxime).

3. The resin composition according to claim 1 or 2, characterized in that, The photosensitive polymer includes a carboxyl polymer containing unsaturated bonds; Preferably, the photosensitive polymer is prepared by reacting epoxy resin with (meth)acrylic acid monomer and then with acid anhydride.

4. The resin composition according to any one of claims 1-3, characterized in that, The epoxy resin includes any one or a combination of at least two of the following: bisphenol A type epoxy resin, phosphorus-containing epoxy resin, isocyanate modified epoxy resin, phenolic epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene-containing epoxy resin, and alicyclic epoxy resin. Preferably, the acrylate monomers include difunctional acrylate monomers and / or polyfunctional acrylate monomers; Preferably, the thermosetting accelerator includes imidazole compounds.

5. The resin composition according to any one of claims 1-4, characterized in that, The packing material is an inorganic packing material and / or an organic packing material, preferably an inorganic packing material; Preferably, the inorganic filler includes any one or a combination of at least two of the following: silicon dioxide, aluminum hydroxide, aluminum oxide, talc, aluminum nitride, boron nitride, silicon carbide, barium sulfate, barium titanate, strontium titanate, calcium carbonate, calcium silicate, and mica. Preferably, the organic filler includes any one or a combination of at least two of the following: polyphenylene ether filler, polytetrafluoroethylene filler, polyetheretherketone filler, polyphenylene sulfide filler, and polyethersulfone filler; Preferably, the median particle size of the filler is 0.01-1 μm.

6. The resin composition according to any one of claims 1-5, characterized in that, The resin composition further includes 0.05-2 parts of pigment by weight; Preferably, the resin composition further comprises 0.05-1 parts by weight of a sensitizer.

7. A photosensitive resin film, characterized in that, The material of the photosensitive resin film includes the resin composition as described in any one of claims 1-6.

8. A resin-coated copper foil, characterized in that, The resin-coated copper foil comprises a copper foil layer and a resin layer, wherein the material of the resin layer comprises the resin composition as described in any one of claims 1-6.

9. A metal foil-coated laminate, characterized in that, The metal foil laminate includes the photosensitive resin film as described in claim 7 and / or the resin-coated copper foil as described in claim 8.

10. A printed circuit board, characterized in that, The printed circuit board includes at least one of the photosensitive resin film as described in claim 7, the resin-coated copper foil as described in claim 8, and the metal foil laminate as described in claim 9.

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