Photosensitive dry film and preparation method and application thereof

Abstract

The invention 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 that alkali-soluble resin, modified resin, a photosensitive monomer, a photoinitiator, methyl alcohol, acetone and a defoaming agent are added into a stirring kettle to be stirred, and photosensitive resin slurry is obtained; coating the substrate layer with the photosensitive resin slurry, and baking to form a photosensitive layer; and attaching the protective layer to the photosensitive layer to obtain the photosensitive film. Wherein the alkali-soluble resin is obtained by taking ethyl methacrylate, methacrylic acid, benzyl acrylate, styrene and dodecafluoroheptyl methacrylate as monomers to react. The photosensitive dry film prepared by the invention has excellent adhesive force and resolution, good acid resistance, electroplating resistance, hole covering performance and etching resistance, and is helpful for improving the yield and increasing the productivity.

Description

Technical Field

[0001] The invention belongs to the technical field of photosensitive materials, and in particular relates to a photosensitive dry film and a preparation method and application thereof. Background Art

[0002] In the field of electronic manufacturing, especially in the production process of printed circuit boards, photosensitive dry film plays a vital role. The development background of this material is closely related to the demand of the electronic industry for high-density and fine circuits. With the advancement of science and technology, various electronic devices are gradually becoming smaller, lighter and more efficient, which puts higher requirements on the manufacturing process of printed circuit boards. Photosensitive dry film came into being, which not only meets the requirements of these refined production, but also promotes the technological progress of the entire industry. Photosensitive dry film mainly consists of three layers: substrate layer, photosensitive layer containing special chemical components and protective layer. The photosensitive layer contains substances that can react under light conditions. Through this characteristic, during the manufacturing process of printed circuit boards, the photosensitive dry film can be accurately exposed according to the designed circuit pattern. With the development of emerging technologies such as 5G, Internet of Things and artificial intelligence, the market demand for high-performance printed circuit boards is increasing, which also prompts the continuous innovation of photosensitive dry film, which is more environmentally friendly and efficient, and can support more complex and sophisticated circuit designs.

[0003] At present, there are also some challenges in the preparation process of photosensitive dry film. For example, most photosensitive dry films are solvent-based, and organic solvents are used for coating and development during preparation, which not only increases the risk of environmental pollution, but also has high costs and inconvenient operation, limiting its scope of application; the adhesion problem of photosensitive dry film is also a key point, especially when facing substrates with complex shapes or different materials (metal, glass, ceramic, etc.), how to ensure that the dry film can firmly adhere to the surface of the substrate without peeling or blistering is a difficulty that needs to be solved urgently; the resolution of photosensitive dry film also has room for improvement. As electronic devices continue to develop towards miniaturization, the demand for finer and more precise circuits is increasing. Existing photosensitive dry films may have insufficient resolution when making extremely fine line widths and spacings. In addition, some photosensitive dry films perform poorly in terms of chemical resistance, especially in acidic or alkaline environments, and are easily corroded, affecting performance stability and service life.

[0004] In order to overcome the shortcomings of the above-mentioned photosensitive dry film, some solutions have been proposed in the prior art. By developing a new water-soluble dry film to replace the traditional solvent-based dry film, the use of organic solvents can be reduced, so as to reduce environmental pollution and costs. In view of the adhesion problem, a new primer is developed to enhance the adhesion between the dry film and different substrates, which solves the peeling and blistering phenomenon to a certain extent. 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 performance is ensured. Although the above methods can solve some problems, there is still a lot of 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, so as to improve product yield and resolution. Summary of the invention

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

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a photosensitive dry film, comprising the following steps:

[0008] H1, add 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 defoamer into a stirring kettle, stir at room temperature and 300-500 r / min for 40-60 minutes to obtain a photosensitive resin slurry;

[0009] H2. Coating the photosensitive resin slurry on the substrate layer, and baking at 80-90° C. for 7-12 minutes to form a photosensitive layer; attaching a protective layer to the photosensitive layer for protection to obtain the photosensitive dry film.

[0010] Preferably, the method for preparing 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 evenly, heated, then 2-4 parts by weight of azobisisobutyronitrile are added to react, and then 2-4 parts by weight of azobisisobutyronitrile are added to continue the reaction, and vacuum distillation is performed and cooling is performed to obtain an alkali-soluble resin.

[0012] The present invention adopts the alkali-soluble resin prepared by the above method as the main raw material of the photosensitive layer, which can effectively improve the adhesion, resolution and acid resistance of the photosensitive dry film to the special substrate (metal, glass, ceramic, etc.). The alkali-soluble resin prepared by the present invention is copolymerized by a specific ratio of ethyl methacrylate, methacrylic acid, benzyl acrylate, styrene and dodecafluoroheptyl methacrylate. The addition of these monomers jointly endows the resin with excellent properties. Methacrylic acid provides a carboxyl group, so that the resin has good water solubility and alkali solubility, which helps to form fine patterns during the development process and improve the resolution. At the same time, the carboxyl group can also enhance the interaction between the resin and the substrate surface and improve the adhesion performance; benzyl acrylate increases the cross-linking density between the resin molecular chains, which is conducive to improving the hardness and adhesion after film formation. Styrene, as a hard segment component, increases the rigidity and thermal stability of the polymer, ensuring the dimensional stability and chemical corrosion resistance during the processing process; and dodecafluoroheptyl methacrylate contains a long-chain fluoroalkyl group, and its low surface energy characteristics not only improve the anti-pollution ability and acid resistance of the material, but also can improve the resolution and adhesion of the photosensitive dry film by adjusting the internal structure of the polymer.

[0013] Furthermore, 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 evenly, then heated to 95-110° C., 2-4 parts by weight of azobisisobutyronitrile are added to react for 6-8 hours, and then 2-4 parts by weight of azobisisobutyronitrile are added to continue the reaction for 4-6 hours, and the mixture is distilled under reduced pressure to a solid content of 40-50%, and cooled to room temperature to obtain an alkali-soluble resin.

[0015] The present invention also adds a modified resin and an alkali-soluble resin for use in combination, which further improves the adhesion and resolution of the photosensitive dry film. In the preparation process of the modified resin, glycidyl hexadecyl ether reacts with 2,3-dimethylsuccinic acid under the catalysis of triphenylphosphine to generate a terminal carboxyl long-chain structure. This structure 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 group with the terminal carboxyl long-chain structure to introduce the flexible long chain into the epoxy resin, thereby enhancing the toughness of the entire system and 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 a ring-opening reaction, which not only increases the crosslinking density of the material, but also provides further functional The addition of tetrahydrophthalic anhydride provides a reaction basis. By reacting with the side hydroxyl group, carboxyl groups are introduced into the resin structure to give the resin alkali solubility. The epoxy group in 3-glycidyloxypropylmethyldiethoxysilane reacts with part of the carboxyl groups to successfully introduce silane groups. The introduction of silane groups significantly improves the adhesion and wear resistance of the photosensitive dry film to a variety of substrates (such as metal, glass, ceramics, etc.). The obtained modified resin is used in combination with an alkali-soluble resin, which can greatly improve the adhesion and resolution of the photosensitive dry film while ensuring the excellent physical and mechanical properties of the material, meeting the needs of modern industry for high-performance photosensitive dry films.

[0016] Preferably, the method for preparing the modified resin comprises the following steps:

[0017] 8-12 parts by weight of glycidyl hexadecyl ether, 6-10 parts by weight of 2,3-dimethylsuccinic acid and 0.3-0.5 parts by weight of triphenylphosphine are uniformly mixed and heated for reaction, and then 100-150 parts by weight of epoxy resin, 0.5-0.8 parts by weight of 5-methylresorcinol and 50-60 parts by weight of 1,5-pentanediol diacrylate are added to continue the reaction, followed by adding 10-30 parts by weight of methacrylic acid and 10-20 parts by weight of ethyl methacrylate, raising the temperature, and then adding 15-18 parts by weight of tetrahydrophthalic anhydride and 12-15 parts by weight of 3-glycidyloxypropylmethyldiethoxysilane to continue the reaction, and cooling to obtain a modified resin.

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

[0019] 8-12 parts by weight of glycidyl hexadecyl ether, 6-10 parts by weight of 2,3-dimethylsuccinic acid and 0.3-0.5 parts by weight of triphenylphosphine are uniformly mixed, reacted at 85-95° C. in a nitrogen atmosphere for 1-2 hours, then 100-150 parts by weight of epoxy resin, 0.5-0.8 parts by weight of 5-methylresorcinol and 50-60 parts by weight of 1,5-pentanediol diacrylate are added and the reaction is continued for 1-2 hours, then 10-30 parts by weight of methacrylic acid and 10-20 parts by weight of ethyl methacrylate are added, the temperature is raised to 95-110° C. and the reaction is carried out for 2-4 hours, then 15-18 parts by weight of tetrahydrophthalic anhydride and 12-15 parts by weight of 3-glycidyloxypropylmethyldiethoxysilane are added and the reaction is continued for 1-3 hours, and the mixture is cooled to room temperature to obtain a modified resin.

[0020] Preferably, the epoxy resin is epoxy resin E44, with an epoxy equivalent of 210-240 g / eq and a viscosity (25° C.) of 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 perfluorooctylpropyl acrylate.

[0022] The present invention optimizes the resolution and adhesion of the photosensitive dry film by selecting a compound of three photosensitive monomers, namely, ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctylpropyl acrylate, and utilizing their respective characteristics. First, since ethoxylated trimethylolpropane triacrylate contains multiple ethoxy units in its molecule, this not only increases the flexibility of the molecular chain, but also improves the compatibility with other components, and helps to form a more uniform coating film, thereby improving the resolution. At the same time, the multi-functional characteristics enable it to form a cross-linked network during the polymerization process, thereby enhancing the strength, adhesion and chemical resistance of the dry film. As a high-functionality acrylate, dipentaerythritol hexaacrylate has extremely high reactivity and can quickly participate in the polymerization reaction to form a highly cross-linked structure, which is crucial for improving the hardness, wear resistance and thermal stability of the dry film. The introduction of perfluorooctylpropyl acrylate mainly utilizes the low surface energy characteristics brought by its fluorinated chain segment to effectively improve the hydrophobicity and anti-pollution ability of the material, reduce the interaction between the dry film and the external environment, and further enhance the weather resistance and chemical resistance of the dry film. 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, by adjusting their proportions, can significantly improve the resolution and adhesion of the photosensitive dry film while maintaining good physical and mechanical properties.

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

[0024] Among them, the CAS number of ethoxylated trimethylolpropane triacrylate is 28961-43-5, the CAS number of dipentaerythritol hexaacrylate is 29570-58-9, and the CAS number of perfluorooctylpropyl 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] Furthermore, the photoinitiator is a mixture of photoinitiator TCDM and photoinitiator EMK in a weight ratio of 1-3:1.

[0027] Among them, 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 defoamer is one of defoamer BYK-024, defoamer BYK-011, defoamer 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 invention also provides a photosensitive dry film prepared by the method.

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

[0032] Compared with the prior art, the advantages and beneficial effects of the present invention are:

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

[0034] 2. The present invention adopts a specific alkali-soluble resin as the main raw material of 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 film 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 can improve the resolution and adhesion of the photosensitive dry film by adjusting the internal structure of the polymer.

[0035] 3. The present invention optimizes the resolution and adhesion of the photosensitive dry film by selecting the compound of three photosensitive monomers, namely, ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctylpropyl acrylate, and utilizing their respective characteristics. Among them, the multifunctional characteristics of ethoxylated trimethylolpropane triacrylate enable it to form a cross-linked network during the polymerization process, thereby enhancing the strength, adhesion and chemical resistance of the dry film; dipentaerythritol hexaacrylate has high reactivity and can quickly participate in the polymerization reaction to form a highly cross-linked structure, which plays a positive role in enhancing adhesion; and the introduction of perfluorooctylpropyl acrylate improves the overall resolution. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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, add 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 stir at room temperature and 400 r / min for 50 min to obtain a photosensitive resin slurry;

[0040] H2, coating the photosensitive resin slurry on the substrate layer, baking at 85°C for 10 minutes to form a photosensitive layer; attaching the protective layer to the photosensitive layer for protection to obtain the photosensitive dry film. The substrate layer is a PET film with a thickness of 15.5 μm; the photosensitive layer is 40 μm thick; and the protective layer is a PE film with a thickness of 19 μm.

[0041] The photosensitive monomer is a mixture of ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctylpropyl 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 evenly, then heated to 100° C., 3 parts by weight of azobisisobutyronitrile are added and reacted for 7 hours, and then 3 parts by weight of azobisisobutyronitrile are added and the reaction is continued for 5 hours, and the mixture is distilled under reduced pressure to a solid content of 45%, and cooled to room temperature to obtain an 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-dimethylsuccinic acid and 0.4 parts by weight of triphenylphosphine were mixed uniformly, reacted at 90°C in a nitrogen atmosphere for 1.5 hours, then 120 parts by weight of epoxy resin E44, 0.6 parts by weight of 5-methylresorcinol and 55 parts by weight of 1,5-pentanediol diacrylate were added to continue the reaction for 1.5 hours, then 20 parts by weight of methacrylic acid and 15 parts by weight of ethyl methacrylate were added, the temperature was raised to 100°C for reaction for 3 hours, then 16 parts by weight of tetrahydrophthalic anhydride and 14 parts by weight of 3-glycidyloxypropylmethyldiethoxysilane were added to continue the reaction for 2 hours, and the modified resin was obtained by cooling to room temperature. Among them, the epoxy equivalent of epoxy resin E44 is 210-240 g / eq, and the viscosity (25°C) is 15000-25000 mPa·s.

[0047] Example 2

[0048] This embodiment provides a method for preparing a photosensitive dry film, comprising the following steps:

[0049] H1, adding 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 defoamer BYK-024 into a stirring kettle, stirring at room temperature and 300 r / min for 40 minutes to obtain a photosensitive resin slurry;

[0050] H2, coating the photosensitive resin slurry on the substrate layer, baking at 80°C for 7 minutes to form a photosensitive layer; attaching the protective layer to the photosensitive layer for protection to obtain the photosensitive dry film. The substrate layer is a PET film with a thickness of 13 μm; the photosensitive layer has a thickness of 38 μm, and the protective layer is a PE film with a thickness of 17 μm.

[0051] The photosensitive monomer is a mixture of ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctylpropyl 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] This embodiment provides a method for preparing a photosensitive dry film, comprising the following steps:

[0057] H1, add 60 parts by weight of alkali-soluble resin, 25 parts by weight of modified resin, 25 parts by weight of photosensitive monomer, 4 parts by weight of photoinitiator, 8 parts by weight of methanol, 5 parts by weight of acetone and 0.3 parts by weight of defoamer BYK-024 into a stirring kettle, and stir at room temperature and 500 r / min for 60 minutes to obtain a photosensitive resin slurry;

[0058] H2, coating the photosensitive resin slurry on the substrate layer, baking at 90°C for 12 minutes to form a photosensitive layer; attaching the protective layer to the photosensitive layer for protection to obtain the photosensitive dry film. The substrate layer is a PET film with a thickness of 17 μm; the photosensitive layer is 42 μm thick, and the protective layer is a PE film with a thickness of 21 μm.

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

[0060] The photoinitiator is a mixture of photoinitiator TCDM and photoinitiator EMK in a weight ratio of 3:1.

[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, which is 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 evenly, then heated to 100° C., 3 parts by weight of azobisisobutyronitrile are added and reacted for 7 hours, and then 3 parts by weight of azobisisobutyronitrile are added and the reaction is continued for 5 hours, and the mixture is distilled under reduced pressure to a solid content of 45%, and cooled to room temperature to obtain an 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, which is 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 and 30 parts by weight of styrene are added to 400 parts by weight of xylene and mixed evenly, then heated to 100°C, 3 parts by weight of azobisisobutyronitrile are added and reacted for 7 hours, and then 3 parts by weight of azobisisobutyronitrile are added and the reaction is continued for 5 hours, and the mixture is distilled under reduced pressure to a solid content of 45%, and cooled to room temperature to obtain an 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, which is as follows: The preparation method of the modified resin comprises the following steps:

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

[0072] Comparative Example 4

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

[0074] 10 parts by weight of glycidyl hexadecyl ether, 8 parts by weight of 2,3-dimethylsuccinic acid and 0.4 parts by weight of triphenylphosphine were mixed uniformly, reacted at 90°C in a nitrogen atmosphere for 1.5 hours, then 120 parts by weight of epoxy resin E44, 0.6 parts by weight of 5-methylresorcinol and 55 parts by weight of 1,5-pentanediol diacrylate were added to continue the reaction for 1.5 hours, then 20 parts by weight of methacrylic acid and 15 parts by weight of ethyl methacrylate were added, the temperature was raised to 100°C for reaction for 3 hours, 16 parts by weight of tetrahydrophthalic anhydride were added to continue the reaction for 2 hours, and the modified resin was obtained by cooling to room temperature. Among them, the epoxy equivalent of 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 this comparative example and Example 1 is that the modified resin is replaced by an alkali-soluble resin, specifically as follows: In the method for preparing the photosensitive dry film, step H1 is to add 70 parts by weight of an alkali-soluble resin, 20 parts by weight of a photosensitive monomer, 3 parts by weight of a photoinitiator, 6 parts by weight of methanol, 4 parts by weight of acetone and 0.2 parts by weight of a defoaming agent BYK-024 into a stirring kettle, and stir at room temperature and 400 r / min for 50 minutes to obtain a photosensitive resin slurry.

[0077] Comparative Example 6

[0078] The difference between this 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 perfluorooctylpropyl acrylate in a weight ratio of 2:2.

[0079] Comparative Example 7

[0080] The difference between this 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 perfluorooctylpropyl acrylate in a weight ratio of 3:2.

[0081] Comparative Example 8

[0082] The difference between this 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 in a weight ratio of 3:2.

[0083] Performance Testing

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

[0085] Film lamination: The glass substrate is sequentially subjected to alkaline washing (NaOH solution, 30°C, 0.15MPa, time 50s), water washing (30°C, 0.15MPa, time 50s), and air drying (30°C, time 25s) to obtain the substrate surface. The substrate inlet temperature before lamination is 40°C, and the outlet temperature is 55°C; the lamination roller temperature is set to 110°C, and the lamination pressure is 4.0±1.0kg / cm 2 , the film pasting speed is 1.0m / min.

[0086] Exposure: Exposure equipment: Haisheng manual exposure machine, exposure scale: Stouffer / 21ST exposure scale sensitivity test piece; exposure grid number ST is 6±1 (21 grid exposure scale), exposure energy is 200mJ / cm 2 . The resist pattern was observed using an optical microscope, and the adhesion (μm) was evaluated by the value of the minimum line width remaining without peeling and curling. The smaller the value, the better the adhesion. The resist pattern was observed using an optical microscope, and the resolution (μm) was taken as the minimum mask line width for normally forming a cured resist line. The smaller the value, the better the resolution.

[0087] Development: Build a small developer to test the height of developing foam, the removal of developing scum and developing mud; ① 0.60 (m 2 *mil) / L of dry film was added to 1.0wt% Na2CO3 solution without adding defoamer. At 30℃, the water pump was turned on for 90 minutes. The foam height at 30 minutes and 90 minutes was recorded respectively. ② Add 1m 2 The dry film was added to 1L of 1.0wt% Na2CO3 solution without defoamer, and stirred at 300RPM for 1 hour under yellow light at 30°C using a stirrer, and then stirred at 3000RPM for 4 hours using a high-speed disperser. After the stirred liquid was left for 1 day, it was filtered with filter paper to confirm whether there was any sludge left. The weight of the residue remaining on the filter paper was weighed (excellent: <0.5g; good: 0.5-1g; fair: 1-1.5g; poor: >1.5g).

[0088] Etching: Anti-hydrofluoric acid etching, after exposure and development according to 7SST / 21SST, put the substrate into 10% hydrofluoric acid solution at room temperature and soak it for 10 minutes. Take out the substrate, wipe the surface solution clean, pull the line with 3M tape, observe whether there is dry film falling off, and measure the thickness of glass thinning in the etched area.

[0089] Stripping: The stripping liquid is NaOH solution with a concentration of 3.0wt%, a temperature of 50°C, a pressure of 0.12MPa, a speed of 50±10% of the stripping point, and water washing after stripping (room temperature, time 50s).

[0090] Table 1: Performance test results of photosensitive dry films (Examples 1-3)

[0091]

[0092]

[0093] Table 2: Performance test results of photosensitive dry films (Comparative Examples 1-8)

[0094]

[0095] It can be seen from the above performance test results that the photosensitive dry films prepared in Examples 1-3 have excellent adhesion, resolution and chemical resistance (acid resistance), especially the comprehensive performance of the photosensitive dry film of Example 1 is the most outstanding. This is because the present invention significantly improves the adhesion, resolution and chemical resistance of the photosensitive dry film by adopting specific alkali-soluble resins, modified resins and photosensitive monomers as key components of the photosensitive resin slurry.

[0096] In comparison, since Comparative Examples 1-8 do not adopt the necessary technical solutions, their corresponding performance tests are significantly worse than those of Examples 1-3. In Comparative Examples 1-2, no specific alkali-soluble resin is used, in Comparative Examples 3-5, no modified resin prepared by a specific method is used, and in Comparative Examples 6-8, no specific combination of photosensitive monomers is used. It can be seen from the results that this leads to a decrease in the adhesion and resolution of the photosensitive dry film. The above experimental results further prove the importance of the technical solutions defined in the present invention for its technical effects.

[0097] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a photosensitive dry film, characterized in that: The following steps are involved: H1, adding 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 defoamer into a stirring kettle, stirring at room temperature and 300-500 r / min for 40-60 minutes to obtain a photosensitive resin slurry; the alkali-soluble resin is obtained by reacting ethyl methacrylate, methacrylic acid, benzyl acrylate, styrene and dodecafluoroheptyl methacrylate as monomers; H2. Coating the photosensitive resin slurry on the substrate layer, and baking at 80-90° C. for 7-12 minutes to form a photosensitive layer; and laminating the protective layer on the photosensitive layer to obtain the photosensitive dry film.

2. The method for preparing a photosensitive dry film according to claim 1, characterized in that: The preparation method of the alkali-soluble resin comprises the following steps: 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 evenly, heated, then 2-4 parts by weight of azobisisobutyronitrile are added to react, and then 2-4 parts by weight of azobisisobutyronitrile are added to continue the reaction, and vacuum distillation is performed and cooling is performed to obtain an alkali-soluble resin.

3. The method for preparing a photosensitive dry film according to claim 2, characterized in that: The preparation method of the alkali-soluble resin comprises the following steps: 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 evenly, then heated to 95-110° C., 2-4 parts by weight of azobisisobutyronitrile are added to react for 6-8 hours, and then 2-4 parts by weight of azobisisobutyronitrile are added to continue the reaction for 4-6 hours, and the mixture is distilled under reduced pressure to a solid content of 40-50%, and cooled to room temperature to obtain an alkali-soluble resin.

4. The method for preparing a photosensitive dry film according to claim 1, characterized in that: The preparation method of the modified resin comprises the following steps: 8-12 parts by weight of glycidyl hexadecyl ether, 6-10 parts by weight of 2,3-dimethylsuccinic acid and 0.3-0.5 parts by weight of triphenylphosphine are uniformly mixed and heated for reaction, and then 100-150 parts by weight of epoxy resin, 0.5-0.8 parts by weight of 5-methylresorcinol and 50-60 parts by weight of 1,5-pentanediol diacrylate are added to continue the reaction, followed by adding 10-30 parts by weight of methacrylic acid and 10-20 parts by weight of ethyl methacrylate, raising the temperature, and then adding 15-18 parts by weight of tetrahydrophthalic anhydride and 12-15 parts by weight of 3-glycidyloxypropylmethyldiethoxysilane to continue the reaction, and cooling to obtain a modified resin.

5. The method for preparing a photosensitive dry film according to claim 4, characterized in that: The preparation method of the modified resin comprises the following steps: 8-12 parts by weight of glycidyl hexadecyl ether, 6-10 parts by weight of 2,3-dimethylsuccinic acid and 0.3-0.5 parts by weight of triphenylphosphine are uniformly mixed, reacted at 85-95° C. in a nitrogen atmosphere for 1-2 hours, then 100-150 parts by weight of epoxy resin, 0.5-0.8 parts by weight of 5-methylresorcinol and 50-60 parts by weight of 1,5-pentanediol diacrylate are added and the reaction is continued for 1-2 hours, then 10-30 parts by weight of methacrylic acid and 10-20 parts by weight of ethyl methacrylate are added, the temperature is raised to 95-110° C. and the reaction is carried out for 2-4 hours, then 15-18 parts by weight of tetrahydrophthalic anhydride and 12-15 parts by weight of 3-glycidyloxypropylmethyldiethoxysilane are added and the reaction is continued for 1-3 hours, and the mixture is cooled to room temperature to obtain a modified resin.

6. The method for preparing a photosensitive dry film according to claim 1, characterized in that: The photosensitive monomer is a mixture of ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and perfluorooctylpropyl acrylate in a weight ratio of 3:1-3:1-3.

7. The method for preparing a 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.

8. The method for preparing a photosensitive dry film according to claim 1, characterized in that: The defoamer is one of defoamer BYK-024, defoamer BYK-011, and defoamer BYK-012, or a mixture of two or more thereof.

9. A photosensitive dry film, characterized in that: Prepared according to the method according to any one of claims 1 to 8.

10. Use of the photosensitive dry film according to claim 9 in preparing a printed circuit board, a lead frame or a semiconductor packaging substrate.

Images