Photosensitive resin composition, photosensitive dry film and printed wiring board

Abstract

The invention discloses a photosensitive resin composition, a photosensitive dry film and a printed circuit board, and relates to the technical field of macromolecules. The photosensitive resin composition comprises the following components in parts by weight: alkali-soluble resin, a photopolymerization monomer and a photoinitiator, the absorbance of the photosensitive resin composition under ultraviolet light with the wavelength of 365 nm is A, the absorbance of the photosensitive resin composition under blue light with the wavelength of 405 nm is B, and the A / B is 1.0-3.0, so that the problems that the photosensitive resin composition in the prior art is low in exposure speed and is only suitable for single-wavelength application are solved.

Description

Technical Field

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

[0002] In the manufacturing processes of electronic devices such as printed circuit boards (PCBs), lead frames (LFs), solar cells, and semiconductor packaged (IC) substrates, photosensitive resin compositions are widely used as key materials for pattern transfer. With continuous technological advancements, the exposure process has gradually shifted from traditional methods using patterned masks and high-pressure mercury lamps or LEDs as light sources to more advanced laser direct imaging (LDI). This method eliminates the need for masks and directly uses a laser source of a specific wavelength, such as 355nm (Nd:YV). Precise exposure is achieved using lasers at frequencies of 305nm (3rd harmonics), 375nm (semiconductor lasers), and 405nm (GaN semiconductor lasers). LDI technology has become a mainstream trend in the PCB industry due to its superior ability to achieve high-precision patterns and its cost advantages (especially the low cost and ease of integration of 405nm semiconductor lasers). However, this technological advancement has brought new challenges. In PCB manufacturing, exposure speed is one of the key factors determining production efficiency. Ordinary dry film resists use hexaaryldiimidazole compounds as initiators, resulting in relatively slow exposure speeds and low exposure efficiency on LDI exposure machines, which limits the production speed and cost of PCB manufacturing. Simultaneously, existing photosensitive resin compositions only have high resolution under a single wavelength of light, limiting the accuracy and fineness of pattern transfer. Summary of the Invention

[0003] The main objective of this invention is to provide a photosensitive resin composition, a photosensitive dry film, and a printed circuit board to solve the problems of slow exposure speed and applicability to a single wavelength in the prior art.

[0004] To achieve the above objectives, according to one aspect of the present invention, a photosensitive resin composition is provided, comprising an alkali-soluble resin, a photopolymerizable monomer, and a photoinitiator; the absorbance of the photosensitive resin composition under ultraviolet light at a wavelength of 365 nm is A, and the absorbance of the photosensitive resin composition under blue light at a wavelength of 405 nm is B, satisfying that A / B is 1.0 to 3.0.

[0005] Furthermore, A / B is 1.5 to 2.5.

[0006] Further, based on parts by weight, the photosensitive resin composition comprises: 40-70 parts by weight of alkali-soluble resin, 20-50 parts by weight of photopolymerizable monomer, and 3-10 parts by weight of photoinitiator.

[0007] The photoinitiator includes a first photoinitiator and a second photoinitiator, with a weight ratio of 3.5:(0.1~0.5) between the first photoinitiator and the second photoinitiator.

[0008] The first photoinitiator includes at least one of 2,4,5-triarylimidazolium dimer compounds, ketone photoinitiators, N-phenylglycine, acridine compounds, and coumarin compounds; the second photoinitiator is a pyrazoline compound.

[0009] Preferably, the second photoinitiator is a pyrazoline compound represented by formula A.

[0010]

[0011] Formula A;

[0012] In the formula, R1 is selected from phenyl, R2 is selected from any one of biphenyl, biphenyl vinyl, methoxyphenyl vinyl, and fused ring groups, and R3 is selected from any one of methoxyphenyl, biphenyl, and benzothiophene.

[0013] Furthermore, the second photoinitiator includes at least one of the compounds shown in Formula I, Formula II, and Formula III:

[0014]

[0015] Formula I;

[0016]

[0017] Formula II;

[0018]

[0019] Formula III.

[0020] Further, the 2,4,5-triarylimidazolium dimer compounds include at least one of 2,2'-di(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole and (2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-diimidazole); the ketone photoinitiators include at least one of 4,4'-bis(diethylamino)benzophenone and 4,4'-bis(dimethylamino)benzophenone; the acridine compounds include at least one of 9-phenylacridine, 9-(p-methylphenyl)acridine, and 9-(m-methylphenyl)acridine; and the coumarin compounds include 7-diethylamino-4-methylcoumarin.

[0021] Preferably, the first photoinitiator comprises at least one of 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole, 4,4'-bis(diethylamino)benzophenone, and N-phenylglycine;

[0022] More preferably, the first photoinitiator is composed of 2,4,5-triarylimidazolium dimer compounds, ketone photoinitiators, and N-phenylglycine.

[0023] Furthermore, the alkali-soluble resin is copolymerized from comonomers, wherein the comonomers include at least two of the following: acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, benzyl methacrylate, styrene, and cyclohexyl methacrylate.

[0024] Preferably, the comonomer includes at least three of the following: methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and benzyl methacrylate.

[0025] Furthermore, the weight-average molecular weight of the alkali-soluble resin is 50,000 g / mol to 150,000 g / mol;

[0026] And / or, the acid value of the alkali-soluble resin is 100mgKOH / g~200mgKOH / g;

[0027] Preferably, the weight-average molecular weight of the alkali-soluble resin is 80,000 g / mol to 120,000 g / mol;

[0028] Preferably, the acid value of the alkali-soluble resin is 120 mg KOH / g to 200 mg KOH / g.

[0029] Furthermore, the photopolymerizable monomers include at least one of the following: nonylphenol acrylate, ethoxylated nonylphenol acrylate, ethoxylated propionylphenol acrylate, ethoxylated propionyl dimethacrylate, bisphenol A dimethacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propionyl trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate;

[0030] Preferably, the photosensitive resin composition further includes: 0.2 to 5.0 parts by weight of additives and 100 to 200 parts by weight of solvent, wherein the additives include at least one of adhesion promoters, plasticizers, dyes, fillers, flame retardants, stabilizers, leveling agents, peel promoters, antioxidants, fragrances, imaging agents, and thermal crosslinking agents.

[0031] According to another aspect of the present invention, a photosensitive dry film is provided, which is obtained by mixing and drying the aforementioned photosensitive resin composition.

[0032] According to another aspect of the present invention, a printed circuit board is provided, wherein the fabrication process of the printed circuit board uses the aforementioned photosensitive dry film.

[0033] By applying the technical solution of this invention, the absorbance ratio of the photosensitive resin composition under two different wavelengths of light, 365nm and 405nm, is controlled, enabling the photosensitive resin composition to have excellent exposure speed and resolution at both wavelengths of 365nm and 405nm. At the same time, it also helps to significantly improve the adhesion between the photosensitive dry film formed by the photosensitive resin composition and the substrate, as well as the electroplating resistance of the photosensitive dry film, thereby effectively improving production yield and product quality. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0035] As described in the background section of this invention, existing photosensitive resin compositions suffer from slow exposure speeds and are only applicable to single wavelengths. To address these issues, in a typical embodiment of this invention, a photosensitive resin composition is provided, wherein the absorbance of the photosensitive resin composition under ultraviolet light at a wavelength of 365 nm is A, and the absorbance of the photosensitive resin composition under blue light at a wavelength of 405 nm is B, satisfying that A / B is 1.0 to 3.0.

[0036] By controlling the absorbance ratio of the photosensitive resin composition to 1.0~3.0 under two different wavelength light sources, it means that the photosensitive resin composition can absorb sufficient 365nm ultraviolet light and 405nm blue light to generate enough free radicals or cations to initiate the polymerization reaction and form a clear cured pattern. Secondly, when the A / B ratio is 1.0~3.0, it indicates that the photosensitive resin composition can have an appropriate exposure speed at both wavelengths, avoiding exposure that is too fast or too slow at a certain wavelength. This helps to maintain the stability and predictability of the process in different processes, improving production efficiency and yield. In addition, at wavelengths of 365nm and 405nm, the photosensitive resin composition can form a clear pattern while maintaining good adhesion to the substrate, which helps to optimize the resolution and adhesion of the film layer.

[0037] Specifically, A / B can be a range consisting of 1.0, 1.1, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, or any two of them.

[0038] In some preferred embodiments, A / B is 1.5 to 2.5. Further control of the A / B value range helps achieve better exposure balance, resulting in finer patterns while maintaining good film adhesion. It also helps enhance the electroplating resistance of the photosensitive dry film formed from the photosensitive resin composition, reduces plating defects, and improves circuit reliability and consistency.

[0039] In some embodiments, the photosensitive resin composition comprises, by weight parts: 40-70 parts by weight of alkali-soluble resin, 20-50 parts by weight of photopolymerizable monomer, and 3-10 parts by weight of photoinitiator; wherein the photoinitiator comprises a first photoinitiator and a second photoinitiator, and the weight ratio of the first photoinitiator to the second photoinitiator is 3.5:(0.1-0.5).

[0040] Specifically, the weight ratio of the first photoinitiator to the second photoinitiator can be a range of 3.5:0.1, 3.5:0.15, 3.5:0.2, 3.5:0.25, 3.5:0.3, 3.5:0.35, 3.5:0.4, 3.5:0.45, 3.5:0.5, or any two of these.

[0041] In some embodiments, the first photoinitiator includes at least one of 2,4,5-triarylimidazolium dimer compounds, ketone photoinitiators, N-phenylglycine, acridine compounds, and coumarin compounds. The 2,4,5-triarylimidazolium dimer compounds include at least one of 2,2'-di(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole and (2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-diimidazole); the ketone photoinitiators include at least one of 4,4'-bis(diethylamino)benzophenone and 4,4'-bis(dimethylamino)benzophenone; the acridine compounds include at least one of 9-phenylacridine, 9-(p-methylphenyl)acridine, and 9-(m-methylphenyl)acridine; and the coumarin compounds include 7-diethylamino-4-methylcoumarin. The second photoinitiator is a pyrazoline compound.

[0042] In some embodiments, the second photoinitiator is a pyrazoline compound represented by formula A:

[0043]

[0044] Formula A;

[0045] In formula A, R1 is selected from phenyl, R2 is selected from any one of biphenyl, biphenyl vinyl, methoxyphenyl vinyl, or fused ring group, and R3 is selected from any one of methoxyphenyl, biphenyl, or benzothiophene group.

[0046] The first photoinitiator described above exhibits high sensitivity to 365nm ultraviolet light, while the second initiator, satisfying the aforementioned structural formula, is sensitive to 405nm blue light. By controlling the ratio of the two initiators to 3.5:(0.1~0.5), the photocuring performance of the photosensitive resin composition on both conventional exposure machines (365nm ultraviolet light) and LDI exposure machines (405nm blue light) can be optimized. This allows the photosensitive resin composition to maintain good exposure speeds on both types of machines, avoiding excessive bias towards one light source that could lead to performance degradation under the other. Controlling the weight ratio of the first photoinitiator to the second photoinitiator to 3.5:(0.1~0.5) helps balance the photopolymerization reaction of the photosensitive resin composition during exposure, preventing pattern blurring or loss of detail due to overexposure or underexposure, thereby improving the resolution of the final image. Furthermore, controlling the photosensitive resin composition to satisfy the aforementioned component and ratio relationships helps improve the formation of a uniform and robust dry film photosensitive layer, thereby enhancing the adhesion of the dry film photosensitive layer to the substrate. During electroplating, the dry film photosensitive layer needs to resist the erosion of the micro-etching solution and the electroplating solution to protect the exposed patterned areas. The proportion of photoinitiator affects the structural and chemical stability of the dry film photosensitive layer. By controlling the photosensitive resin composition to meet the above-mentioned component and ratio relationships, the electroplating resistance of the dry film photosensitive layer can be enhanced, the occurrence of plating penetration can be reduced, and the circuit yield can be improved.

[0047] In some embodiments, the second photoinitiator includes at least one of Formula I, Formula II, and Formula III:

[0048]

[0049] Formula I;

[0050]

[0051] Formula II;

[0052]

[0053] Formula III.

[0054] Specifically, alkali-soluble resins are used to provide basic adhesion and etching resistance. Photopolymerizable monomers are the foundation for the formation of polymer networks during photocuring. Under the influence of light, photoinitiators generate free radicals or cations, thereby initiating the polymerization reaction of the photopolymerizable monomers.

[0055] In some embodiments, the first photoinitiator includes at least one selected from 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole, 4,4'-bis(diethylamino)benzophenone, and N-phenylglycine. The aforementioned first photoinitiator exhibits high photosensitivity at a wavelength of 365 nm and can rapidly decompose to generate free radicals or cations, thereby accelerating the photopolymerization reaction. The presence of the first photoinitiator helps improve the exposure speed and resolution of the photosensitive resin composition on a conventional exposure machine. Simultaneously, it helps improve the photocuring efficiency and film uniformity of the photosensitive resin composition, enabling the photosensitive resin composition to cure rapidly even at lower exposure energies, forming clear, high-precision patterns, thereby improving exposure speed and film quality.

[0056] In some preferred embodiments, the first photoinitiator is composed of a 2,4,5-triarylimidazolium dimer, a ketone photoinitiator, and N-phenylglycine.

[0057] In some embodiments, the alkali-soluble resin is copolymerized from comonomers, wherein the comonomers include at least two selected from acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, benzyl methacrylate, styrene, and cyclohexyl methacrylate. By controlling the specific types of comonomers to meet the above requirements, it is helpful to prepare an alkali-soluble resin with suitable molecular weight and acid value, which helps to promote excellent properties of the photosensitive resin composition, including good development speed, substrate adhesion, and electroplating resistance.

[0058] In some preferred embodiments, the comonomer includes at least three of methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and benzyl methacrylate. By controlling the comonomer to include at least three of the above comonomers, a balance of multifunctionality can be achieved, which helps to improve the developing properties, electroplating resistance, and film hardness of the photosensitive resin composition, as well as the transparency, mechanical strength, and leveling properties of the photosensitive resin composition.

[0059] In some embodiments, the weight-average molecular weight of the alkali-soluble resin is 50,000 g / mol to 150,000 g / mol. Controlling the weight-average molecular weight affects the flexibility of the alkali-soluble resin and the resolution of the resist layer. By controlling the weight-average molecular weight of the alkali-soluble resin to meet the above requirements, it helps to achieve an optimal balance in the photosensitive resin composition, maintaining good solubility to ensure rapid development while providing sufficient mechanical strength and film stability, thereby maintaining the integrity of the pattern during post-exposure development and etching. Specifically, the weight-average molecular weight of the alkali-soluble resin can be within the range of 50,000 g / mol, 60,000 g / mol, 70,000 g / mol, 80,000 g / mol, 90,000 g / mol, 100,000 g / mol, 110,000 g / mol, 120,000 g / mol, 130,000 g / mol, 140,000 g / mol, 150,000 g / mol, or any combination thereof. In some preferred embodiments, the weight-average molecular weight of the alkali-soluble resin is 80,000 g / mol to 120,000 g / mol.

[0060] In some embodiments, the acid value of the alkali-soluble resin is 100 mg KOH / g to 200 mg KOH / g. The acid value measures the content of acidic functional groups in the resin, and its control affects the development speed of the alkali-soluble resin and the stability of the resist layer. By controlling the acid value of the alkali-soluble resin to meet the above requirements, it ensures that the alkali-soluble resin has a suitable development speed while rapidly removing unexposed areas without damaging the cured pattern, thus facilitating high-precision pattern transfer. Simultaneously, it also helps improve the etching resistance of the cured film layer because the carboxylic acid groups can be converted into more stable groups after photocuring, reducing dissolution during subsequent etching processes and protecting the circuit from damage. Specifically, the acid value of the alkali-soluble resin can be within the range of 100 mg KOH / g, 110 mg KOH / g, 120 mg KOH / g, 130 mg KOH / g, 140 mg KOH / g, 150 mg KOH / g, 160 mg KOH / g, 170 mg KOH / g, 180 mg KOH / g, 190 mg KOH / g, 200 mg KOH / g, or any combination thereof. In some preferred embodiments, the acid value of the alkali-soluble resin is 120 mg KOH / g to 200 mg KOH / g.

[0061] In some embodiments, the photopolymerizable monomers include at least one selected from nonylphenol acrylate, ethoxylated nonylphenol acrylate, ethoxylated propionic nonylphenol acrylate, ethoxylated propionic dimethacrylate, bisphenol A dimethacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propionic trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate. By controlling the specific type of photopolymerizable monomer, it is helpful to optimize the crosslinking density of the photosensitive dry film formed by the photosensitive resin composition after exposure, thereby further enhancing the stability of the photosensitive resin composition.

[0062] In some preferred embodiments, the photosensitive resin composition further includes 0.2 to 5.0 parts by weight of additives and 100 to 200 parts by weight of solvent. The present invention does not limit the specific type of additives, which can be selected according to actual needs. For example, the additives include at least one of adhesion promoters, plasticizers, dyes, fillers, flame retardants, stabilizers, leveling agents, peel accelerators, antioxidants, fragrances, imaging agents, and thermal crosslinking agents. Specifically, the addition of solvent helps to promote thorough mixing between the components of the photosensitive resin composition; the solvent can be of a type conventionally used in the art, preferably acetone. The dye can be malachite green, brilliant green, leuco crystal violet, etc.

[0063] In a second aspect, the present invention provides a photosensitive dry film, which is obtained by mixing and drying the above-mentioned photosensitive resin composition. The above-mentioned photosensitive resin composition can be used in both UV exposure machines and LDI exposure machines, and the photosensitive dry film formed from the above-mentioned photosensitive resin composition has excellent exposure speed, resolution, adhesion performance and electroplating resistance, thereby improving production efficiency and yield, and is suitable for large-scale circuit board production lines.

[0064] In a specific implementation of this invention, the above-mentioned photosensitive resin composition can be mixed and directly coated onto a support layer. After drying, a photosensitive layer is formed. Then, a protective layer is laminated onto the photosensitive layer to finally obtain a photosensitive dry film. The protective layer serves to protect the photosensitive layer and prevent its performance from deteriorating. In practical use, the protective layer can be removed to allow the photosensitive layer to adhere to the element to be processed, and the support layer can be removed to cover the surface of the element to be processed. The element to be processed can be a conventional electronic device in the art, the support layer can be a PET film, and the protective layer can be a polyethylene (PE) film.

[0065] In a third aspect, the present invention provides a printed circuit board, the preparation process of which uses the aforementioned photosensitive dry film.

[0066] Printed circuit boards are manufactured using the aforementioned photosensitive dry film, for example, according to the following steps: First, the photosensitive layer of the photosensitive dry film is laminated onto a circuit forming substrate such as a copper-clad laminate. Next, the photosensitive layer is exposed through a support layer to form a photocurable portion. At this time, the support layer is peeled off before or after exposure. Then, the area of ​​the photosensitive layer other than the photocurable portion is removed with a developer to form a resist pattern. Next, the resist pattern is used as a resist for etching or plating to form a conductor pattern, and finally, the photocurable portion (resist pattern) of the photosensitive layer is peeled off (removed).

[0067] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0068] I. Raw Material Preparation

[0069] In the following examples and comparative examples, the comonomers of the alkali-soluble resin used were methacrylic acid, methyl methacrylate, and butyl methacrylate in a mass ratio of 25:45:30. The weight-average molecular weight (Mw) of the alkali-soluble resin was 97,000, and the acid value was 163 mg KOH / g. Specifically, the comonomers corresponding to the alkali-soluble resin were mixed evenly according to the mass ratio (total 100 g), and then mixed with 0.4 g of initiator AIBN, 100 g of butanone, and 5 g of ethanol to obtain a mixed solution, which was stirred and dissolved. Part of the mixed solution was added to a three-necked flask equipped with nitrogen protection and a reflux condenser using a peristaltic pump. The mixture was heated to 80°C in an oil bath, and after stirring for 1 hour, the remaining mixed solution was added dropwise, with all the mixed solution added within 3 hours. The reaction was continued at this temperature for 4 hours, then the temperature was raised to 85°C, and 5 g of butanone solution containing 0.2 g of initiator was added. The reaction was then maintained at this temperature for 3 hours to terminate the reaction and obtain the alkali-soluble resin.

[0070] The specific parameters of the photopolymerizable monomers used in the following examples and comparative examples are as follows:

[0071] Photopolymerizable monomer B-1: (4) nonylphenol acrylate ethoxylate (from Changzhou Qiangli Electronic Materials);

[0072] Photopolymerizable monomer B-2: (6) ethoxylated (12) propoxylated dimethacrylate, (from Changzhou Qiangli Electronic Materials);

[0073] Photopolymerizable monomer B-3: (10) Bisphenol A dimethacrylate ester ethoxylate (derived from Sartoma);

[0074] Photopolymerizable monomer B-4: (9) Ethoxytrimethylolpropane triacrylate (derived from Sartoma).

[0075] The specific parameters of the photoinitiators used in the following examples and comparative examples are as follows:

[0076] Photoinitiator C-1: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole (derived from Changzhou Qiangli Electronic Materials);

[0077] Photoinitiator C-2: 4,4'-bis(diethylamino)benzophenone (derived from Aldrich);

[0078] Photoinitiator C-3: N-phenylglycine (derived from Aldrich);

[0079] Photoinitiator C-4: 1-Phenyl-3-biphenyl-5-(4-methoxyphenyl)pyrazoline, as shown in Formula I, and prepared as shown in Synthesis Example 1;

[0080] Photoinitiator C-5: 1-Phenyl-3-(biphenylvinyl)-5-biphenylpyrazoline, as shown in Formula II, and prepared as shown in Synthesis Example 2;

[0081] Photoinitiator C-6: 1-phenyl-3-(biphenyl)-5-(2-benzothiophene)pyrazoline, as shown in Formula III, and prepared as in Synthesis Example 3.

[0082]

[0083] Formula I;

[0084]

[0085] Formula II;

[0086]

[0087] Formula III.

[0088] Synthesis example 1:

[0089] In a 500 mL three-necked flask, add 117 g of biphenyl ethyl ketone, 68 g of p-methoxybenzaldehyde, and 200 mL of ethanol. Place the flask in a water bath at room temperature and stir for 15 min until the raw materials dissolve. Then, add 40 g of 40% NaOH aqueous solution dropwise over 1 h. After the addition is complete, continue stirring at room temperature for 8 h. Monitor the reaction by spot TLC. Stop the reaction when the p-methoxybenzaldehyde is completely consumed. Filter the resulting suspension under reduced pressure. Disperse the crude solid product in a small amount of ethanol (150 mL). Stir at room temperature for 30 min, filter, collect the solid, and dry it using a rotary evaporator. After removing the small amount of solvent trapped in the solid, the intermediate product compound 1 (145 g, 92% purity) shown in the following reaction structure is obtained.

[0090] In a 500 mL three-necked flask, intermediate compound 1 (145 g) and glacial acetic acid (300 g) were added. The mixture was placed in an oil bath and heated to 50 °C with stirring. At 50 °C, phenylhydrazine (95 g) was slowly added dropwise over a period of 1 h. After the addition was complete, the temperature was raised to 80 °C and the reaction was carried out for 8 h. The reaction was monitored by spot TLC plate. After the raw materials were completely consumed, the reaction was stopped. After cooling to room temperature, ethanol (300 mL) was added for dilution. The resulting suspension was stirred at room temperature for 30 min and then filtered under reduced pressure. The crude solid product required further purification. It was dispersed in a small amount of methanol (150 mL), stirred at room temperature for 30 min, filtered, and the solid was collected. It was dried using a rotary evaporator. After removing the small amount of solvent encapsulated in the solid, the following reaction structure (1) was obtained (122 g, purity 95.5%) of pyrazoline compound was obtained.

[0091] Its specific reaction structure is shown in the following reaction structure (1):

[0092]

[0093] Reaction structure (1).

[0094] Synthesis example 2:

[0095] In a 1000 mL three-necked flask, p-phenylbenzaldehyde (182 g), acetone (29 g), and ethanol (300 mL) were added. The flask was placed in a water bath at room temperature and stirred for 15 min until the raw materials dissolved. Then, 10% NaOH aqueous solution (480 g) was added dropwise over 2 h. After the addition was complete, the reaction was continued to be stirred at room temperature for 8 h. The reaction was monitored by spot TLC plate. The reaction was stopped when the reaction no longer changed. The resulting suspension was filtered under reduced pressure. The crude solid product was dispersed in a small amount of ethanol (150 mL). After stirring at room temperature for 30 min, the mixture was filtered, and the solid was collected. It was dried using a rotary evaporator to remove the small amount of solvent trapped in the solid, yielding intermediate product compound 2 (180 g, 90% purity) as shown in the following reaction structural formula.

[0096] In a 500 mL three-necked flask, intermediate compound 2 (120 g) and glacial acetic acid (300 g) were added. The mixture was placed in an oil bath and heated to 50 °C with stirring. At 50 °C, phenylhydrazine (55 g) was slowly added dropwise over a period of 1 h. After the addition was complete, the temperature was raised to 80 °C and the reaction was carried out for 8 h. The reaction was monitored by spot TLC plate. After the raw materials were completely consumed, the reaction was stopped. After cooling to room temperature, ethanol (300 mL) was added for dilution. The resulting suspension was stirred at room temperature for 30 min and then filtered under reduced pressure. The crude solid product required further purification. It was dispersed in a small amount of methanol (150 mL), stirred at room temperature for 30 min, filtered, and the solid was collected. It was dried using a rotary evaporator. After removing the small amount of solvent encapsulated in the solid, the following reaction structure (2) showed a pyrazoline compound (101 g, purity 96%).

[0097] Its specific reaction structure is shown in reaction structure (2):

[0098]

[0099] Reaction structure (2).

[0100] Synthesis example 3:

[0101] In a 500 mL three-necked flask, 58 g of biphenyl ethyl ketone, 40 g of benzothiophene-2-carboxaldehyde, and 150 mL of ethanol were added. The flask was placed in a water bath at room temperature and stirred for 15 min until the raw materials dissolved. Then, 20 g of 40% NaOH aqueous solution was added dropwise over 1 h. After the addition was complete, the reaction was continued at room temperature with stirring for 8 h. The reaction was monitored by spot TLC. The reaction was stopped when the raw material benzothiophene-2-carboxaldehyde was completely consumed. The resulting suspension was filtered under reduced pressure. The crude solid product was dispersed in a small amount of ethanol (150 mL), stirred at room temperature for 30 min, filtered, and the solid was collected. It was dried using a rotary evaporator to remove the small amount of solvent trapped in the solid, yielding the intermediate product compound 5 (83 g, 93% purity) as shown in the following reaction structural formula.

[0102] In a 500 mL three-necked flask, intermediate compound 5 (83 g) and glacial acetic acid (200 g) were added. The mixture was placed in an oil bath and heated to 50 °C with stirring. At 50 °C, phenylhydrazine (42 g) was slowly added dropwise over a period of 1 h. After the addition was complete, the temperature was raised to 80 °C and the reaction was carried out for 8 h. The reaction was monitored by spot TLC plate. After the raw materials were completely consumed, the reaction was stopped. After cooling to room temperature, ethanol (200 mL) was added for dilution. The resulting suspension was stirred at room temperature for 30 min and then filtered under reduced pressure. The crude solid product required further purification. It was dispersed in a small amount of methanol (150 mL), stirred at room temperature for 30 min, filtered, and the solid was collected. It was dried using a rotary evaporator. After removing the small amount of solvent encapsulated in the solid, the following reaction structure (3) showed a pyrazoline compound (67 g, purity 95%).

[0103] Its specific reaction structure is shown in the following reaction structure (3):

[0104]

[0105] Reaction structure (3).

[0106] The specific parameters of the additives used in the following examples and comparative examples are as follows:

[0107] Dye D-1: Brilliant Green (from Aldrich);

[0108] Dye D-2: Leuco Crystal Violet (derived from Aldrich).

[0109] II. Preparation of Photosensitive Resin Compositions

[0110] The components and formulations of the photosensitive resin compositions in Examples 1-8 and Comparative Examples 1-2 are shown in Table 1, and the specific preparation methods are as follows:

[0111] According to the formula shown in Table 1, the components were mixed in proportion. The alkali-soluble resin was added according to its solid content, with an appropriate amount of butanone added. The mixture was then stirred thoroughly until completely dissolved, preparing a resin composition solution with a solid content of 50%. The solution was kept at 30°C in a water bath, and then uniformly coated onto the surface of a 15μm thick PET support film using a coating machine. It was then dried in a 95°C oven for 10 minutes to form a 40μm thick photosensitive layer, which appeared green under yellow light. A 20μm thick polyethylene protective film was then laminated onto the surface of the photosensitive layer to form a PE protective layer, resulting in a three-layer photosensitive laminate.

[0112] Table 1

[0113]

[0114] Test methods

[0115] The sample preparation methods (including film application, exposure, development, pattern electroplating, and film removal) of the examples and comparative examples, the sample evaluation methods, and the evaluation results.

[0116] [Screen protector]

[0117] The film was applied using a Changzhou Changyao Electronics CYL-M25 film applicator with a pressure of 4 kg / cm². 2 The speed is 1 m / min and the temperature is 110℃.

[0118]

exposure

[0119] After the film was applied, the sample was left to stand for more than 15 minutes before exposure using a UV exposure machine and an LDI exposure machine. The UV exposure machine was a Zhisheng UVE-M552, and the LDI exposure machine was a Yingsu RS-RD-25. The number of exposure grids was measured using a Stouffer 41-step exposure ruler, and the number of exposure grids was controlled within the range of 17 to 23.

[0120]

development

[0121] After exposure, the sample should be allowed to stand for at least 15 minutes. The development temperature is 30℃, and the pressure is 1.5 kg / cm². 2 The developer is a 1.0% wt sodium carbonate aqueous solution, and the development time is 1.5 to 2.0 times the minimum development time. After development, the product is washed with water and dried.

[0122] [Graphic plating]

[0123] The electroplating solution used is Zhengtianwei copper sulfate and stannous sulfate system. Copper is plated first, followed by tin plating, as follows: acid degreasing (10% concentration, 10 min, 40℃), water rinsing for 2 min, micro-etching for 1 min (sodium persulfate 60 g / L + concentrated sulfuric acid 20 ml / L), water rinsing for 1 min, acid immersion for 1 min (10% sulfuric acid solution), copper electroplating (current density 2 ASD, temperature 22-27℃, time 60 min), water rinsing for 1 min, acid immersion for 1 min (10% sulfuric acid solution), tin electroplating (current density 1 ASD, temperature 20-25℃, time 10 min).

[0124] [Removal of film]

[0125] Alkaline stripping solution, NaOH, stripping temperature 50℃, pressure 1.5 kg / cm². 2 The stripping solution concentration is 3~5wt%, the stripping time is 1.5~2.0 times the minimum stripping time, and the film is washed with water and dried after stripping.

[0126] [Evaluation of the Analysis]

[0127] Using a wiring pattern with equal line spacing and width (incrementing by 2.5 μm each time) of Line / Space = 10 / 10-70 / 70 μm, exposure and development were performed. After washing and drying, the pattern was observed with a magnifying glass, and the minimum width of the normally formed cured resist line was recorded as the analytical value.

[0128] [Evaluation of Attachment]

[0129] Using a line spacing of equal spacing and different line widths of equidistant line widths (Line / Space = n / 400μm, n ranging from 10 to 70, increasing by 2.5 each time), the wire patterns were exposed and developed. After washing and drying, they were observed with a magnifying glass. The minimum width of the line that formed the complete cured resist was recorded as the adhesion value.

[0130] Evaluation of electroplating resistance

[0131] After film application, exposure, development, pattern electroplating, and film removal, scanning electron microscopy (SEM) is used to test and observe whether there is any plating leakage.

[0132] ○: No plating penetration;

[0133] △: Slight plating penetration;

[0134] ×: Severe plating penetration;

[0135] Evaluation of UV absorption

[0136] The Agilent Cary 4000 UV-Vis spectrophotometer was used for the test, with a wavelength range of 200~800nm. Air was used as the background sample. The protective film was removed before testing the sample. The absorbance at 365nm and 405nm was recorded as A and B, respectively. The absorbance ratio of 365nm / 405nm was A / B.

[0137] The test results are shown in Table 2.

[0138] Table 2

[0139]

[0140] As shown in Table 2, compared with the comparative example, by controlling the A / B ratio to be 1.0~3.0, the photosensitive resin composition of the example can be used in both UV exposure machines and LDI exposure machines. It has good compatibility with different types of exposure machines and has good exposure speed, resolution, adhesion and electroplating resistance.

[0141] Furthermore, compared to Examples 4 and 7, Examples 1-3, 5-6, and 8 further controlled the A / B ratio to 1.5-2.5. Compared to Examples 4 and 7, the exposure speed, resolution, adhesion, and electroplating resistance of the photosensitive resin compositions in Examples 1-3, 5-6, and 8 were further improved.

[0142] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A photosensitive resin composition, characterized in that, The photosensitive resin composition comprises an alkali-soluble resin, a photopolymerizable monomer, and a photoinitiator; the absorbance of the photosensitive resin composition under ultraviolet light at a wavelength of 365 nm is A, and the absorbance of the photosensitive resin composition under blue light at a wavelength of 405 nm is B, satisfying that A / B is 1.0~3.

0.

2. The photosensitive resin composition according to claim 1, characterized in that, The A / B ratio is 1.5 to 2.

5.

3. The photosensitive resin composition according to claim 1 or 2, characterized in that, The photosensitive resin composition comprises, by weight parts: 40-70 parts by weight of alkali-soluble resin, 20-50 parts by weight of photopolymerizable monomer, and 3-10 parts by weight of photoinitiator. The photoinitiator includes a first photoinitiator and a second photoinitiator, wherein the weight ratio of the first photoinitiator to the second photoinitiator is 3.5:(0.1~0.5). The first photoinitiator includes at least one of 2,4,5-triarylimidazolium dimer compounds, ketone photoinitiators, N-phenylglycine, acridine compounds, and coumarin compounds; the second photoinitiator is a pyrazoline compound. Preferably, the second photoinitiator is a pyrazoline compound represented by formula A; Formula A; In the formula, R1 is selected from phenyl, R2 is selected from any one of biphenyl, biphenyl vinyl, methoxyphenyl vinyl, and fused ring groups, and R3 is selected from any one of methoxyphenyl, biphenyl, and benzothiophene.

4. The photosensitive resin composition according to claim 3, characterized in that, The second photoinitiator includes at least one of the compounds shown in Formula I, Formula II, and Formula III: Formula I; Formula II; Formula III.

5. The photosensitive resin composition according to claim 3, characterized in that, The 2,4,5-triarylimidazolium dimer compounds include at least one of 2,2'-di(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole and (2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-diimidazole); the ketone photoinitiator includes at least one of 4,4'-bis(diethylamino)benzophenone and 4,4'-bis(dimethylamino)benzophenone; the acridine compounds include at least one of 9-phenylacridine, 9-(p-methylphenyl)acridine, and 9-(m-methylphenyl)acridine; the coumarin compounds include 7-diethylamino-4-methylcoumarin; Preferably, the first photoinitiator comprises at least one of 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole, 4,4'-bis(diethylamino)benzophenone, and N-phenylglycine; More preferably, the first photoinitiator is composed of 2,4,5-triarylimidazolium dimer compounds, ketone photoinitiators, and N-phenylglycine.

6. The photosensitive resin composition according to any one of claims 1 to 5, characterized in that, The alkali-soluble resin is copolymerized from comonomers, wherein the comonomers include at least two of the following: acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, benzyl methacrylate, styrene, and cyclohexyl methacrylate. Preferably, the comonomer includes at least three of the following: methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and benzyl methacrylate.

7. The photosensitive resin composition according to any one of claims 1 to 5, characterized in that, The weight-average molecular weight of the alkali-soluble resin is 50,000 g / mol to 150,000 g / mol; And / or, the acid value of the alkali-soluble resin is 100 mg KOH / g to 200 mg KOH / g; Preferably, the weight-average molecular weight of the alkali-soluble resin is 80,000 g / mol to 120,000 g / mol; Preferably, the acid value of the alkali-soluble resin is 120 mg KOH / g to 200 mg KOH / g.

8. The photosensitive resin composition according to any one of claims 1 to 5, characterized in that, The photopolymerizable monomers include at least one of the following: nonylphenol acrylate, ethoxylated nonylphenol acrylate, ethoxylated propionylphenol acrylate, ethoxylated propionyl dimethacrylate, bisphenol A dimethacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propionyl trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate. Preferably, the photosensitive resin composition further includes: 0.2 to 5.0 parts by weight of additives and 100 to 200 parts by weight of solvent, wherein the additives include at least one of adhesion promoters, plasticizers, dyes, fillers, flame retardants, stabilizers, leveling agents, peeling promoters, antioxidants, fragrances, imaging agents, and thermal crosslinking agents.

9. A photosensitive dry film, characterized in that, The photosensitive dry film is obtained by mixing and drying the photosensitive resin composition according to any one of claims 1 to 8.

10. A printed circuit board, characterized in that, The printed circuit board is prepared using the photosensitive dry film described in claim 9.

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