Photosensitive dry film, method for preparing the same, and use thereof

Abstract

The application provides a photosensitive dry film and a preparation method and application thereof, and belongs to the technical field of photosensitive materials. The preparation method comprises the following steps: adding an alkali-soluble resin, a modified resin, a photosensitive monomer, a photoinitiator, methanol, acetone and a defoaming agent into a stirring kettle to stir, so as to obtain a photosensitive resin slurry; coating the photosensitive resin slurry on a substrate layer, baking, and forming a photosensitive layer; and attaching a protective layer to the photosensitive layer, so that the photosensitive dry film is obtained. The alkali-soluble resin is obtained by monomer reaction of ethyl methacrylate, methacrylic acid, benzyl acrylate, styrene and dodecafluoroheptyl methacrylate. The photosensitive dry film prepared by the application has excellent adhesion and resolution, good acid resistance, plating resistance, hole covering performance and etching resistance, and is helpful to improve the yield and increase the production capacity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of photosensitive materials, and particularly relates to a photosensitive dry film and a preparation method and application thereof. BACKGROUND

[0002] In the field of electronic manufacturing, especially in the production process of printed circuit boards, photosensitive dry films play a crucial role. The development of this material is closely related to the demand for high-density and fine lines in the electronics industry. With the advancement of technology, various electronic devices are gradually moving towards miniaturization, portability, and high performance, which puts higher requirements on the manufacturing process of printed circuit boards. Photosensitive dry films emerged as the times require, not only meeting the requirements of these fine production, but also promoting the technological progress of the entire industry. Photosensitive dry films are mainly composed of three layers: a substrate layer, a photosensitive layer containing special chemical components, and a protective layer. The photosensitive layer contains substances that can react under light conditions, and through this characteristic, photosensitive dry films can be accurately exposed according to the designed circuit pattern during the manufacturing process of printed circuit boards. With the development of emerging technologies such as 5G, the Internet of Things, and artificial intelligence, the market demand for high-performance printed circuit boards is increasing, which also promotes the continuous innovation of photosensitive dry films, towards more environmentally friendly, more efficient, and support for more complex and fine circuit designs.

[0003] Currently, there are also some challenges in the preparation process of photosensitive dry films. For example, most photosensitive dry films are solvent-based, using organic solvents for coating and developing during preparation, which not only increases the risk of environmental pollution, but also has high cost, inconvenient operation, and limits its application range; the adhesion problem of photosensitive dry films is also a key point, especially when facing complex shapes or different materials (metal, glass, ceramic, etc.) substrates, how to ensure that the dry film can be firmly adhered to the substrate surface without peeling or blistering phenomenon is a difficult problem to be solved; the resolution of photosensitive dry films also has room for improvement, as electronic devices continue to develop towards miniaturization, the demand for finer and more precise lines is increasing, and the existing photosensitive dry films may not have sufficient resolution when making extremely fine lines and spaces. In addition, some photosensitive dry films perform poorly in terms of chemical resistance, especially in acidic or alkaline environments, which can easily affect the performance stability and service life.

[0004] To overcome the shortcomings of the photosensitive dry film, some solutions have been proposed in the prior art. By developing new water-soluble dry films to replace traditional solvent-based dry films, the use of organic solvents is reduced, thereby reducing environmental pollution and costs. To address the adhesion problem, new primers are developed to enhance the adhesion between the dry film and different substrates, which to some extent solves the peeling and blistering problems. By introducing chemical-resistant polymer materials, the stability of the photosensitive dry film in harsh environments is improved, the service life is extended, and the reliability of the performance is ensured. Although the above methods can solve some problems, there is still much room for improvement in photosensitive dry films. Therefore, there is an urgent need for a photosensitive dry film with excellent adhesion, resolution, acid resistance, and chemical resistance to improve product yield and resolution. SUMMARY

[0005] The purpose of the present application is to provide a photosensitive dry film, which further improves the adhesion, resolution, and acid resistance of the photosensitive dry film by using specific alkali-soluble resins, modified resins, and photosensitive monomers, thereby improving the yield and increasing the production capacity.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] The present application provides a preparation method of a photosensitive dry film, comprising the following steps:

[0008] H1, 40-60 parts by weight of alkali-soluble resin, 15-25 parts by weight of modified resin, 15-25 parts by weight of photosensitive monomer, 2-4 parts by weight of photoinitiator, 5-8 parts by weight of methanol, 2-5 parts by weight of acetone, and 0.1-0.3 parts by weight of defoaming agent are added to a stirred tank, stirred at room temperature and 300-500 r / min for 40-60 min to obtain a photosensitive resin slurry;

[0009] H2, the photosensitive resin slurry is coated on the substrate layer and baked at 80-90°C for 7-12 min to form a photosensitive layer; a protective layer is attached to the photosensitive layer for protection to obtain the photosensitive dry film.

[0010] Preferably, the preparation method of the alkali-soluble resin comprises the following steps:

[0011] 20-40 parts by weight of ethyl methacrylate, 10-30 parts by weight of methacrylic acid, 5-15 parts by weight of benzyl acrylate, 20-40 parts by weight of styrene, and 5-15 parts by weight of dodecafluoroheptyl methacrylate are added to 300-500 parts by weight of xylene and mixed uniformly, heated, then 2-4 parts by weight of azobisisobutyronitrile is added for reaction, and then 2-4 parts by weight of azobisisobutyronitrile is added for further reaction, reduced pressure distillation, and cooling to obtain the alkali-soluble resin.

[0012] The alkali-soluble resin prepared by the method can be used as a main raw material of a photosensitive layer, and can effectively improve the adhesion, resolution and acid resistance of the photosensitive dry film and special substrates (metal, glass, ceramic, etc.). The alkali-soluble resin is prepared by copolymerization of ethyl methacrylate, methacrylic acid, benzyl acrylate, styrene and dodecafluoroheptyl methacrylate in a specific ratio. The addition of these monomers endows the resin with excellent properties. The methacrylic acid provides carboxyl groups, so that the resin has good water solubility and alkali solubility, which is helpful to form a fine pattern in the development process and improve the resolution. Meanwhile, the carboxyl groups can also enhance the interaction force between the resin and the surface of the substrate, and improve the adhesion performance. The benzyl acrylate increases the crosslinking density between the molecular chains of the resin, which is beneficial to improve the hardness and adhesion after film formation. The styrene as a hard segment component increases the rigidity and thermal stability of the polymer, and ensures the dimensional stability and chemical corrosion resistance in the processing process. The dodecafluoroheptyl methacrylate contains long-chain fluoroalkyl groups, and the low surface energy characteristics not only improve the pollution resistance and acid resistance of the material, but also improve the resolution and adhesion of the photosensitive dry film by adjusting the internal structure of the polymer.

[0013] Further, the preparation method of the alkali-soluble resin comprises the following steps:

[0014] 20-40 parts by weight of ethyl methacrylate, 10-30 parts by weight of methacrylic acid, 5-15 parts by weight of benzyl acrylate, 20-40 parts by weight of styrene and 5-15 parts by weight of dodecafluoroheptyl methacrylate are added to 300-500 parts by weight of xylene and mixed uniformly, then heated to 95-110℃, 2-4 parts by weight of azobisisobutyronitrile is added and reacted for 6-8h, then 2-4 parts by weight of azobisisobutyronitrile is added and reacted for 4-6h, distilled under reduced pressure until the solid content is 40-50%, and then cooled to room temperature to obtain the alkali-soluble resin.

[0015] The application also adds modified resin and alkali-soluble resin for use, further improving the adhesion and resolution of the photosensitive dry film. In the preparation process of the modified resin, glycidyl cetyl ether and 2,3-dimethyl succinic acid are reacted under the catalysis of triphenyl phosphine to generate a carboxyl-terminated long-chain structure, which not only provides an active site for subsequent reactions, but also helps to improve the toughness of the dry film. Subsequently, epoxy resin is added to react with part of the epoxy groups and the carboxyl-terminated long-chain structure, introducing a flexible long chain into the epoxy resin, thereby enhancing the toughness of the entire system and the adhesion to the substrate. The addition of methacrylic acid and ethyl methacrylate introduces double bonds and side hydroxyl groups on the resin molecular chain through ring-opening reaction, which not only increases the crosslinking density of the material, but also provides a reaction basis for further functionalization. The addition of tetrahydrophthalic anhydride introduces carboxyl groups into the resin structure by reacting with the side hydroxyl groups, giving the resin alkali solubility. The epoxy groups in 3-glycidyl ether oxypropyl methyl diethoxysilane react with part of the carboxyl groups, successfully introducing silane groups. The introduction of silane groups significantly improves the adhesion and wear resistance of the photosensitive dry film to various substrates such as metal, glass, and ceramic. The modified resin obtained by using the modified resin in combination with the alkali-soluble resin can greatly improve the adhesion and resolution of the photosensitive dry film while ensuring excellent physical and mechanical properties of the material, meeting the demand for high-performance photosensitive dry film in modern industry.

[0016] Preferably, the preparation method of the modified resin comprises the following steps:

[0017] 8-12 parts by weight of glycidyl cetyl ether, 6-10 parts by weight of 2,3-dimethyl succinic acid, and 0.3-0.5 parts by weight of triphenyl phosphine are mixed uniformly, heated and reacted, then 100-150 parts by weight of epoxy resin, 0.5-0.8 parts by weight of 5-methyl resorcinol, and 50-60 parts by weight of 1,5-pentanediol diacrylate are added for further reaction, followed by the addition of 10-30 parts by weight of methacrylic acid, 10-20 parts by weight of ethyl methacrylate, heating, and then the addition of 15-18 parts by weight of tetrahydrophthalic anhydride and 12-15 parts by weight of 3-glycidyl ether oxypropyl methyl diethoxysilane for further reaction, and cooling to obtain the modified resin.

[0018] Further, the preparation method of the modified resin comprises the following steps:

[0019] Mix 8-12 parts by weight of glycidyl hexadecyl ether, 6-10 parts by weight of 2,3-dimethyl butanedioic acid and 0.3-0.5 parts by weight of triphenyl phosphorus uniformly, react for 1-2 h at 85-95℃ under nitrogen atmosphere, then add 100-150 parts by weight of epoxy resin, 0.5-0.8 parts by weight of 5-methyl resorcinol and 50-60 parts by weight of 1,5-pentanediol diacrylate to continue to react for 1-2 h, then add 10-30 parts by weight of methacrylic acid, 10-20 parts by weight of ethyl methacrylate, heat to 95-110℃ to react for 2-4 h, then add 15-18 parts by weight of tetrahydrophthalic anhydride, 12-15 parts by weight of 3-glycidyl ether oxypropyl methyl diethoxysilane to continue to react for 1-3 h, cool to room temperature to obtain the modified resin.

[0020] Preferably, the epoxy resin is epoxy resin E44, the epoxy equivalent weight is 210-240 g / eq, and the viscosity (25℃) is 15000-25000 mPa·s.

[0021] Preferably, the photosensitive monomer is one or a mixture of two or more of ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctyl propyl acrylate.

[0022] The present application optimizes the resolution and adhesion of the photosensitive dry film by selecting the combination of ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctyl propyl acrylate, and utilizing their respective characteristics. First, ethoxylated trimethylolpropane triacrylate contains multiple ethoxy units in its molecule, which not only increases the flexibility of the molecular chain, but also improves the compatibility with other components, helping to form a more uniform coating, thereby improving the resolution, and the multi-functional characteristics enable it to form a cross-linked network during polymerization, enhancing the strength, adhesion and chemical resistance of the dry film; dipentaerythritol hexaacrylate, as a high-functionality acrylate, has extremely high reactivity and can quickly participate in polymerization to form a highly cross-linked structure, which is crucial for improving the hardness, wear resistance and thermal stability of the dry film, and also plays a positive role in enhancing adhesion; the introduction of perfluorooctyl propyl acrylate mainly utilizes the low surface energy characteristics of the fluorine-containing segment to effectively improve the hydrophobicity and anti-pollution ability of the material, reducing the interaction between the dry film and the external environment, further enhancing the weather resistance and chemical resistance of the dry film, and due to the presence of fluorine atoms, the surface of the dry film is smoother, which is conducive to the formation of fine patterns and improves the overall resolution; the synergistic cooperation of the three monomers can significantly improve the resolution and adhesion of the photosensitive dry film while maintaining good physical and mechanical properties by adjusting their proportions.

[0023] Further, the photosensitive monomer is a mixture of ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctyl propyl acrylate in a weight ratio of 3:1-3:1-3.

[0024] The CAS number of the ethoxylated trimethylolpropane triacrylate is 28961-43-5, the CAS number of the dipentaerythritol hexaacrylate is 29570-58-9, and the CAS number of the perfluorooctyl propyl acrylate is 1652-60-4.

[0025] Preferably, the photoinitiator is one of photoinitiator TCDM, photoinitiator EMK, photoinitiator BDK, photoinitiator BCIM, photoinitiator 907, photoinitiator 379 or a mixture of two or more thereof.

[0026] Further, the photoinitiator is a mixture of photoinitiator TCDM and photoinitiator EMK in a weight ratio of 1-3:1.

[0027] The CAS number of the photoinitiator TCDM is 100486-97-3, and the CAS number of the photoinitiator EMK is 90-93-7.

[0028] Preferably, the defoaming agent is one of defoaming agent BYK-024, defoaming agent BYK-011, defoaming agent BYK-012 or a mixture of two or more thereof; brand: BYK, Germany.

[0029] Preferably, the substrate layer is a PET film with a thickness of 13-17 μm, the photosensitive layer has a thickness of 38-42 μm, and the protective layer is a PE film with a thickness of 17-21 μm.

[0030] The application also provides a photosensitive dry film prepared by the above method.

[0031] The application also provides the use of the above photosensitive dry film in the preparation of a printed circuit board, a lead frame or a semiconductor packaging substrate.

[0032] Compared with the prior art, the application has the following advantages and beneficial effects:

[0033] 1. The application provides a photosensitive dry film and a preparation method thereof, wherein the alkali-soluble resin obtained by reacting ethyl methacrylate, methacrylic acid, benzyl acrylate, styrene and dodecafluoroheptyl methacrylate as monomers, and the specific photosensitive monomer and modified resin as key components of the photosensitive resin slurry, make the photosensitive dry film have excellent adhesion and resolution, good acid resistance, anti-electroplating ability, hole covering performance and etching resistance, thereby helping to improve the yield and increase the production capacity.

[0034] 2. The present invention uses a specific alkali-soluble resin as the main raw material for the photosensitive layer, which can effectively improve the adhesion, resolution and acid resistance of the photosensitive dry film to special substrates (metal, glass, ceramics, etc.). The resin is copolymerized by a specific ratio of ethyl methacrylate, methacrylic acid, benzyl acrylate, styrene and dodecafluoroheptyl methacrylate. The addition of these monomers together gives the resin excellent properties. Benzyl acrylate increases the cross-linking density between the resin molecular chains, which is beneficial to improving the hardness and adhesion of the film after formation. Dodecafluoroheptyl methacrylate contains a long-chain fluoroalkyl group, and its low surface energy characteristics not only improve the material's anti-pollution ability and acid resistance, but also improve the resolution and adhesion of the photosensitive dry film by adjusting the internal structure of the polymer.

[0035] 3. The present invention utilizes the combined properties of three photosensitive monomers: ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and perfluorooctylpropyl acrylate, to optimize the resolution and adhesion of the photosensitive dry film. The multifunctional nature of ethoxylated trimethylolpropane triacrylate enables it to form a cross-linked network during polymerization, enhancing the dry film's strength, adhesion, and chemical resistance. Dipentaerythritol hexaacrylate exhibits high reactivity and rapidly participates in the polymerization reaction, forming a highly cross-linked structure that contributes positively to adhesion. Furthermore, the introduction of perfluorooctylpropyl acrylate improves overall resolution. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides a method for preparing a photosensitive dry film, comprising the following steps:

[0039] H1, adding 50 parts by weight of alkali-soluble resin, 20 parts by weight of modified resin, 20 parts by weight of photosensitive monomer, 3 parts by weight of photoinitiator, 6 parts by weight of methanol, 4 parts by weight of acetone and 0.2 parts by weight of defoamer BYK-024 into a stirring kettle, and stirring at room temperature and 400 r / min for 50 minutes to obtain a photosensitive resin slurry;

[0040] H2, the photosensitive resin slurry is coated on the substrate layer, baked at 85℃ for 10 min to form a photosensitive layer; a protective layer is attached to the photosensitive layer for protection to obtain the photosensitive dry film. Wherein, the substrate layer is a PET film with a thickness of 15.5μm; the photosensitive layer has a thickness of 40μm; the protective layer is a PE film with a thickness of 19μm.

[0041] The photosensitive monomer is a mixture of ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctyl propyl acrylate in a weight ratio of 3:2:2.

[0042] The photoinitiator is a mixture of photoinitiator TCDM and photoinitiator EMK in a weight ratio of 2:1.

[0043] The preparation method of the alkali-soluble resin comprises the following steps:

[0044] 30 parts by weight of ethyl methacrylate, 20 parts by weight of methacrylic acid, 10 parts by weight of benzyl acrylate, 30 parts by weight of styrene and 10 parts by weight of dodecafluoroheptyl methacrylate are added to 400 parts by weight of xylene and mixed uniformly, then heated to 100℃, 3 parts by weight of azobisisobutyronitrile is added and reacted for 7h, then 3 parts by weight of azobisisobutyronitrile is added and reacted for 5h, and then distilled under reduced pressure to a solid content of 45%, and cooled to room temperature to obtain the alkali-soluble resin.

[0045] The preparation method of the modified resin comprises the following steps:

[0046] 10 parts by weight of glycidyl hexadecyl ether, 8 parts by weight of 2,3-dimethyl succinic acid and 0.4 parts by weight of triphenyl phosphorus are mixed uniformly, reacted at 90℃ under nitrogen atmosphere for 1.5h, then 120 parts by weight of epoxy resin E44, 0.6 parts by weight of 5-methyl resorcinol and 55 parts by weight of 1,5-pentanediol diacrylate are added and reacted for 1.5h, then 20 parts by weight of methacrylic acid, 15 parts by weight of ethyl methacrylate are added and reacted at 100℃ for 3h, then 16 parts by weight of tetrahydrophthalic anhydride, 14 parts by weight of 3-glycidyl ether oxypropyl methyl diethoxysilane are added and reacted for 2h, and then cooled to room temperature to obtain the modified resin. Wherein, the epoxy equivalent weight of the epoxy resin E44 is 210-240g / eq, and the viscosity (25℃) is 15000-25000mPa·s.

[0047] Example 2

[0048] The embodiment provides a preparation method of a photosensitive dry film, comprising the following steps:

[0049] H1, 40 parts by weight of alkali-soluble resin, 15 parts by weight of modified resin, 15 parts by weight of photosensitive monomer, 2 parts by weight of photoinitiator, 5 parts by weight of methanol, 2 parts by weight of acetone and 0.1 parts by weight of defoaming agent BYK-024 are added into a stirring kettle, stirred at room temperature for 40 min at 300 r / min, to obtain a photosensitive resin slurry;

[0050] H2, the photosensitive resin slurry is coated on the substrate layer, baked at 80℃ for 7 min to form a photosensitive layer; a protective layer is attached to the photosensitive layer for protection to obtain the photosensitive dry film. Wherein, the substrate layer is a PET film with a thickness of 13μm; the photosensitive layer has a thickness of 38μm, and the protective layer is a PE film with a thickness of 17μm.

[0051] The photosensitive monomer is a mixture of ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctyl propyl acrylate in a weight ratio of 3:1:1.

[0052] The photoinitiator is a mixture of photoinitiator TCDM and photoinitiator EMK in a weight ratio of 1:1.

[0053] The preparation method of the alkali-soluble resin is the same as that of Example 1.

[0054] The preparation method of the modified resin is the same as that of Example 1.

[0055] Example 3

[0056] The present embodiment provides a preparation method of a photosensitive dry film, comprising the following steps:

[0057] H1, 40 parts by weight of alkali-soluble resin, 15 parts by weight of modified resin, 15 parts by weight of photosensitive monomer, 2 parts by weight of photoinitiator, 5 parts by weight of methanol, 2 parts by weight of acetone and 0.1 parts by weight of defoaming agent BYK-024 are added into a stirring kettle, stirred at room temperature for 40 min at 300 r / min, to obtain a photosensitive resin slurry;

[0058] H2, the photosensitive resin slurry is coated on the substrate layer, baked at 80℃ for 7 min to form a photosensitive layer; a protective layer is attached to the photosensitive layer for protection to obtain the photosensitive dry film. Wherein, the substrate layer is a PET film with a thickness of 13μm; the photosensitive layer has a thickness of 38μm, and the protective layer is a PE film with a thickness of 17μm.

[0059] The photosensitive monomer is a mixture of ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctyl propyl acrylate in a weight ratio of 3:1:1.

[0060] The photoinitiator is a mixture of photoinitiator TCDM and photoinitiator EMK in a weight ratio of 1:1.

[0061] The preparation method of the alkali-soluble resin is the same as that of Example 1.

[0062] The preparation method of the modified resin is the same as that of Example 1.

[0063] Comparative Example 1

[0064] The difference between this comparative example and Example 1 is that the preparation method of the alkali-soluble resin is different, specifically as follows: the preparation method of the alkali-soluble resin comprises the following steps:

[0065] 30 parts by weight of ethyl methacrylate, 20 parts by weight of methacrylic acid, 30 parts by weight of styrene and 10 parts by weight of dodecafluoroheptyl methacrylate are added to 400 parts by weight of xylene and mixed uniformly, then heated to 100°C, 3 parts by weight of azobisisobutyronitrile is added and reacted for 7h, then 3 parts by weight of azobisisobutyronitrile is added and reacted for 5h, distilled under reduced pressure until the solid content is 45%, and cooled to room temperature to obtain the alkali-soluble resin.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 1 is that the preparation method of the alkali-soluble resin is different, specifically as follows: the preparation method of the alkali-soluble resin comprises the following steps:

[0068] 30 parts by weight of ethyl methacrylate, 20 parts by weight of methacrylic acid, 10 parts by weight of benzyl acrylate, 30 parts by weight of styrene are added to 400 parts by weight of xylene and mixed uniformly, then heated to 100°C, 3 parts by weight of azobisisobutyronitrile is added and reacted for 7h, then 3 parts by weight of azobisisobutyronitrile is added and reacted for 5h, distilled under reduced pressure until the solid content is 45%, and cooled to room temperature to obtain the alkali-soluble resin.

[0069] Comparative Example 3

[0070] The difference between this comparative example and Example 1 is that the preparation method of the modified resin is different, specifically as follows: the preparation method of the modified resin comprises the following steps:

[0071] 20 parts by weight of methacrylic acid, 15 parts by weight of ethyl methacrylate are added to 120 parts by weight of epoxy resin E44, heated to 100°C under nitrogen atmosphere and reacted for 3h, then 16 parts by weight of tetrahydrophthalic anhydride, 14 parts by weight of 3-glycidyloxypropylmethyldiethoxysilane are added and reacted for 2h, and cooled to room temperature to obtain the modified resin. The epoxy equivalent weight of the epoxy resin E44 is 210-240g / eq, and the viscosity (25°C) is 15000-25000mPa·s.

[0072] Comparative Example 4

[0073] The difference between the present comparative example and Example 1 is that the preparation method of the modified resin is different, specifically as follows: the preparation method of the modified resin comprises the following steps:

[0074] 10 parts by weight of glycidyl cetyl ether, 8 parts by weight of 2,3-dimethyl succinic acid and 0.4 parts by weight of triphenyl phosphine are uniformly mixed and reacted at 90°C under a nitrogen atmosphere for 1.5 h, then 120 parts by weight of epoxy resin E44, 0.6 parts by weight of 5-methyl resorcinol and 55 parts by weight of 1,5-pentanediol diacrylate are added and reacted for 1.5 h, then 20 parts by weight of methacrylic acid and 15 parts by weight of ethyl methacrylate are added and reacted at 100°C for 3 h, and then 16 parts by weight of tetrahydrophthalic anhydride is added and reacted for 2 h, and then cooled to room temperature to obtain the modified resin. The epoxy equivalent weight of the epoxy resin E44 is 210-240 g / eq, and the viscosity (25°C) is 15000-25000 mPa·s.

[0075] Comparative Example 5

[0076] The difference between the present comparative example and Example 1 is that the modified resin is replaced by an alkali-soluble resin, specifically as follows: in the preparation method of the photosensitive dry film, step H1 is that 70 parts by weight of alkali-soluble resin, 20 parts by weight of photosensitive monomer, 3 parts by weight of photoinitiator, 6 parts by weight of methanol, 4 parts by weight of acetone and 0.2 parts by weight of defoaming agent BYK-024 are added into a stirred tank and stirred at room temperature at 400 r / min for 50 min to obtain a photosensitive resin slurry.

[0077] Comparative Example 6

[0078] The difference between the present comparative example and Example 1 is that the photosensitive monomer is different, specifically as follows: the photosensitive monomer is a mixture of dipentaerythritol hexaacrylate and perfluorooctyl propyl acrylate at a weight ratio of 2:2.

[0079] Comparative Example 7

[0080] The difference between the present comparative example and Example 1 is that the photosensitive monomer is different, specifically as follows: the photosensitive monomer is a mixture of ethoxylated trimethylolpropane triacrylate and perfluorooctyl propyl acrylate at a weight ratio of 3:2.

[0081] Comparative Example 8

[0082] The difference between the present comparative example and Example 1 is that the photosensitive monomer is different, specifically as follows: the photosensitive monomer is a mixture of ethoxylated trimethylolpropane triacrylate and dipentaerythritol hexaacrylate at a weight ratio of 3:2.

[0083] Performance test

[0084] The photosensitive dry films prepared in Examples 1-3 and Comparative Examples 1-8 above were subjected to the following performance tests, and the results are shown in Tables 1 and 2.

[0085] Film sticking: The glass substrate was subjected to alkaline washing (NaOH solution, 30°C, 0.15 MPa, 50 s), water washing (30°C, 0.15 MPa, 50 s), and air drying (30°C, 25 s) in sequence to obtain a substrate surface. The substrate was at an inlet temperature of 40°C and an outlet temperature of 55°C before film sticking. The temperature of the pressure roller for film sticking was set at 110°C, the pressure for film sticking was 4.0±1.0 kg / cm 2 , and the film sticking speed was 1.0 m / min.

[0086] Exposure: Exposure equipment: Haisheng manual exposure machine, exposure scale: Stouffer / 21ST exposure scale sensitivity test sheet; exposure scale number ST was 6±1 (21-scale exposure scale), and the exposure energy was 200 mJ / cm 2 . The adhesion was evaluated by the value of the minimum line width (μm) remaining without peeling and curling, and the smaller the value, the better the adhesion. The resolution was evaluated by the minimum mask line width (μm) of the normal formation of the cured resist line, and the smaller the value, the better the resolution.

[0087] Development: A small development machine was built to test the development foam height, development scum, and development slurry removal. ① 0.60 (m 2 *mil) / L of dry film was added to 1.0 wt% Na2CO3 solution without defoaming agent, and the foam height was recorded at 30 min and 90 min after the pump was opened and circulated at 30°C for 90 min. ② 1 m 2 of dry film was added to 1 L of 1.0 wt% Na2CO3 solution without defoaming agent, and the solution was stirred at 300 RPM for 1 hour under yellow light using a stirrer and then stirred at 3000 RPM for 4 hours using a high-speed disperser. After the solution was stirred uniformly, it was left to stand for 1 day, filtered using filter paper, and whether there was sludge residue was confirmed. The weight of the residue remaining on the filter paper was measured (wherein, excellent: <0.5 g; good: 0.5-1 g; medium: 1-1.5 g; poor: >1.5 g).

[0088] Etching: Hydrofluoric acid etching. The substrate exposed and developed according to 7sst / 21sst was immersed in 10% hydrofluoric acid solution at room temperature for 10 min. After the substrate was taken out and the surface solution was wiped clean, the line was pulled using 3M tape, and whether the dry film fell off was observed, and the etching area glass thinning thickness was measured.

[0089] Peeling: the peeling solution is NaOH solution, the concentration is 3.0wt%, the temperature is 50℃, the pressure is 0.12MPa, the speed is 50±10% of the peeling point, and water washing (room temperature, time 50s) is performed after peeling.

[0090] Table 1: performance test results of the photosensitive dry film (Examples 1-3)

[0091]

[0092]

[0093] Table 2: performance test results of the photosensitive dry film (Comparative Examples 1-8)

[0094]

[0095] From the above performance test results, it can be seen that the photosensitive dry films prepared in Examples 1-3 have excellent adhesion, resolution and chemical resistance (acid resistance), and in particular, the photosensitive dry film of Example 1 has the most outstanding comprehensive performance, because the present application uses a specific alkali-soluble resin, a modified resin and a specific combination of photosensitive monomers as key components of the photosensitive resin slurry, which significantly improves the adhesion, resolution and chemical resistance of the photosensitive dry film.

[0096] In contrast, Comparative Examples 1-8 do not use the necessary technical solutions, resulting in a significant difference in the corresponding performance tests compared to Examples 1-3. In Comparative Examples 1-2, a specific alkali-soluble resin is not used, in Comparative Examples 3-5, a modified resin prepared by a specific method is not used, and in Comparative Examples 6-8, a specific combination of photosensitive monomers is not used. The results show that this leads to a decrease in the adhesion and resolution of the photosensitive dry film. The above experimental results further demonstrate the importance of the technical solutions defined in the present application to its technical effects.

[0097] The above is a preferred embodiment of the present application. It should be noted that for those skilled in the art, without departing from the principles of the present application, several improvements and refinements can be made, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A method for preparing a photosensitive dry film, characterized in that: It comprises the following steps: H1, 40-60 parts by weight of alkali-soluble resin, 15-25 parts by weight of modified resin, 15-25 parts by weight of photosensitive monomer, 2-4 parts by weight of photoinitiator, 5-8 parts by weight of methanol, 2-5 parts by weight of acetone and 0.1-0.3 parts by weight of defoaming agent are added into a stirred tank, stirred at room temperature, 300-500 r / min for 40-60 min to obtain a photosensitive resin slurry; the alkali-soluble resin is obtained by monomer reaction of 20-40 parts by weight of ethyl methacrylate, 10-30 parts by weight of methacrylic acid, 5-15 parts by weight of benzyl acrylate, 20-40 parts by weight of styrene and 5-15 parts by weight of dodecafluoroheptyl methacrylate; H2, the photosensitive resin slurry is coated on the substrate layer and baked at 80-90℃ for 7-12min to form a photosensitive layer; the protective layer is attached to the photosensitive layer to obtain the photosensitive dry film; The modified resin is obtained by reaction of 8-12 parts by weight of glycidyl hexadecyl ether, 6-10 parts by weight of 2,3-dimethyl succinic acid, 0.3-0.5 parts by weight of triphenyl phosphorus, 100-150 parts by weight of epoxy resin, 0.5-0.8 parts by weight of 5-methyl resorcinol, 50-60 parts by weight of 1,5-pentanediol diacrylate, 10-30 parts by weight of methacrylic acid, 10-20 parts by weight of ethyl methacrylate, 15-18 parts by weight of tetrahydrophthalic anhydride and 12-15 parts by weight of 3-glycidyl ether oxypropyl methyl diethoxysilane; The photosensitive monomer is a mixture of ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctyl propyl acrylate in a weight ratio of 3:1-3:1-3; The substrate layer is a PET film with a thickness of 13-17μm; the photosensitive layer has a thickness of 38-42μm, and the protective layer is a PE film with a thickness of 17-21μm.

2. The preparation method of the photosensitive dry film according to claim 1, characterized in that, The photoinitiator is a mixture of photoinitiator TCDM and photoinitiator EMK in a weight ratio of 1-3:

1.

3. The method for preparing a photosensitive dry film according to claim 1, wherein: The defoaming agent is one or a mixture of two or more of defoaming agent BYK-024, defoaming agent BYK-011 and defoaming agent BYK-012.

4. A photosensitive dry film characterized by comprising: Prepared according to any one of claims 1-3.

5. The photosensitive dry film according to claim 4 for use in the preparation of printed circuit boards, lead frames or semiconductor packaging substrates.

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