A water-based photosensitive dry film and a method for preparing the same

Abstract

The application relates to the technical field of photosensitive materials, and discloses a water-based photosensitive dry film and a preparation method thereof. The water-based photosensitive dry film prepared by the application comprises, from top to bottom, a base layer, a photosensitive layer and a protective layer, the base layer is a PET film, the photosensitive layer is a photoresist, and the protective layer is a polyethylene film; the photosensitive layer is formed by coating a photoresist on the surface of the base layer and drying; the photoresist is prepared by taking water-based polyurethane acrylate as main raw material and adding a photoinitiator, a corrosion-resistant modifier and a crosslinking agent and other additives; and the photoresist has excellent adhesion, corrosion resistance and photosensitivity.

Description

Technical Field

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

[0002] Photoresist dry film is a core material in printed circuit board (PCB) manufacturing, primarily used in the pattern transfer process to form a mask pattern that resists etching or plating through exposure and development. Traditional solvent-based photoresist dry film, due to its use of organic solvents (such as acetone and ethyl acetate), poses issues such as volatile organic compound emissions, flammability and explosiveness, and environmental pollution. With increasingly stringent global environmental regulations, water-based photoresist dry film, due to its water-based dispersion medium and low toxicity and environmental friendliness, has become a key development direction in the industry.

[0003] Compared with solvent-based products, water-based photosensitive dry films need to overcome the following technical bottlenecks: (1) Insufficient corrosion resistance: The hydrophilic groups of the water-soluble resin are easily penetrated by the etching solution (acidic / alkaline), resulting in damage to the mask; (2) Weak adhesion: The interfacial bonding strength between the water-based system and the copper substrate is low, and it is easy to peel off during the development or etching process. Based on the above-mentioned defects of water-based photosensitive dry films, researchers need to develop a water-based photosensitive dry film with good corrosion resistance, strong adhesion and environmental protection to meet practical application needs. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a water-sensitive photosensitive dry film and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A water-sensitive photosensitive dry film, comprising, from top to bottom, a base layer, a photosensitive layer, and a protective layer; the base layer is a PET film, the photosensitive layer is a photoresist, and the protective layer is a polyethylene film;

[0007] Furthermore, the photoresist comprises the following raw materials in parts by weight: 40-60 parts of waterborne polyurethane acrylate, 8-15 parts of ethoxy trihydroxy (methyl) propane triacrylate, 4-8 parts of photoinitiator, 1.5-3.5 parts of corrosion resistance modifier, 1-2 parts of defoaming agent, and 15-25 parts of water;

[0008] Furthermore, the solid content of the waterborne polyurethane acrylate is 50%-60%;

[0009] Further, the photoinitiator is one of photoinitiator 369 or initiator 379;

[0010] Furthermore, the defoaming agent is KS66 defoaming agent;

[0011] The corrosion-resistant modifier is prepared by the following steps:

[0012] Step A1: N-allylaniline and isophorone diisocyanate were uniformly dispersed in dichloromethane, respectively designated as solution 1 and solution 2. Solution 2 was slowly added dropwise to solution 1 under nitrogen, and the mixture was stirred at room temperature for 8-12 hours. The mixture was then distilled under reduced pressure and extracted to obtain intermediate product 1.

[0013] Furthermore, in step A1, the molar ratio of N-allylaniline to isophorone diisocyanate is 1:1.05-1.1;

[0014] Furthermore, step A1 is to react the -NH group in N-allylaniline with an -NCO group in isophorone diisocyanate to prepare an intermediate product 1 containing a hindered urea bond;

[0015] Step A2: Allylaminoacetic acid hydrochloride was mixed and stirred in tetrahydrofuran, and 1-hydroxybenzotriazole and N,N-dimethylpyridine were added, and the mixture was stirred in an ice-water bath for 30 minutes. Dicyclohexylcarbodiimide was then added at room temperature, and the mixture was vigorously stirred for 12-16 hours. The tetrahydrofuran was removed by concentration under reduced pressure, and ethyl acetate was added and stirred for 10 minutes. The ethyl acetate was then removed under reduced pressure and purified to obtain intermediate 2.

[0016] Furthermore, in step A2, the molar ratio of allylaminoacetic acid hydrochloride, 1-hydroxybenzotriazole, N,N-dimethylpyridine and dicyclohexylcarbodiimide is 1:1.3-1.5:0.2-0.3:1.2-1.4;

[0017] Furthermore, step A2 is to react the carboxyl group in allylaminoacetic acid hydrochloride with the hydroxyl group in 1-hydroxybenzotriazole to prepare an intermediate product 2 containing a benzotriazole structure and a secondary amine structure;

[0018] Step A3, intermediate product 1 and intermediate product 2 were respectively stirred in dichloromethane, and recorded as solution 3 and solution 4, respectively. Under nitrogen conditions, solution 3 was slowly added dropwise to solution 4, and stirred at 35°C for 10-14 hours. The mixture was distilled under reduced pressure and extracted to obtain a corrosion-resistant modifier;

[0019] Further, in step A3, the molar ratio of intermediate product 1 to intermediate product 2 is 1.03-1.06:1;

[0020] Furthermore, step A3 is to utilize the remaining -NCO group in the intermediate product 1 to react with the secondary amine structure in the intermediate product 2 to prepare a corrosion-resistant modifier.

[0021] A method for preparing a water-sensitive photosensitive dry film comprises the following steps:

[0022] Step S1, weighing raw materials in parts by weight, mixing and evenly stirring waterborne polyurethane acrylate, ethoxy trihydroxy (methyl) propane triacrylate, photoinitiator, corrosion resistance modifier, defoamer and water to obtain a photoresist;

[0023] Step S2: evenly coating the surface of the PET film of the base layer with a photoresist and drying the same to obtain a photosensitive layer;

[0024] Furthermore, the thickness of the photosensitive layer in step S2 is 30 μm;

[0025] Step S3: Lay the protective polyethylene film on the photosensitive layer, and then cut, heat-seal, and roll it up to obtain a water-sensitive photosensitive dry film.

[0026] Beneficial effects of the present invention:

[0027] The water-based photosensitive dry film prepared by the present invention mainly includes a base layer, a photosensitive layer and a protective layer. The photosensitive layer is formed by coating a photoresist on the surface of the base layer and drying it. The photoresist is prepared by using water-based polyurethane acrylate as a main raw material, and adding auxiliary agents such as a photoinitiator, a corrosion-resistant modifier and a cross-linking agent (ethoxytrihydroxy(methyl)propane triacrylate). The photoresist has excellent adhesion, corrosion resistance and photosensitivity. Among them, the corrosion-resistant modifier improves the corrosion resistance of the photosensitive layer, enabling it to stably adhere to the surface of the copper plate, playing a role in blocking electroplating and etching, and is also environmentally friendly.

[0028] The corrosion-resistant modifier introduced into the photoresist prepared by the present invention improves the adhesion of the photoresist to the copper plate and the corrosion resistance of the photoresist itself. The benzotriazole structure introduced into the corrosion-resistant modifier can form coordination bonds with the copper plate surface using its nitrogen atoms, generating a stable complex protective film that prevents direct contact between the copper and the etching solution and inhibits corrosion reactions. The complex formation also improves the adhesion of the photosensitive dry film to the copper plate. The hindered urea bond is a urea bond with a sterically hindered benzene ring structure on one side. The steric hindrance effect of the hindered urea bond restricts the free movement of the polymer molecular chains in the photosensitive dry film, promotes the formation of a dense cross-linked network, effectively blocks the penetration of etching solutions (such as acidic or alkaline solutions), and improves the chemical corrosion resistance. At the same time, the -NH group in the urea bond can also form hydrogen bonds with the surface oxide of the copper substrate, enhancing the adhesion of the photoresist to the substrate and preventing film peeling during pattern transfer. In addition, the double bond structure introduced into the corrosion-resistant modifier enables it to participate in the reaction during the subsequent exposure process, so that it is firmly fixed to the copper plate through chemical bonding, effectively avoiding the reduction in corrosion resistance caused by the easy migration of traditional small molecule corrosion-resistant agents in the photosensitive dry film after exposure. At the same time, the presence of hydrophilic groups enables it to be evenly dispersed in water. DETAILED DESCRIPTION

[0029] 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.

[0030] Example 1: The corrosion-resistant modifier is prepared by the following steps:

[0031] Step A1: 1 mol of N-allylaniline and 1.05 mol of isophorone diisocyanate were uniformly dispersed in 100 mL of dichloromethane, respectively, and recorded as solution 1 and solution 2. Under nitrogen, solution 2 was slowly added dropwise to solution 1, and the mixture was stirred at room temperature for 8 hours. The mixture was then distilled under reduced pressure and extracted to obtain intermediate product 1.

[0032] Step A2: 1 mol of allylaminoacetic acid hydrochloride was mixed and stirred in 100 mL of tetrahydrofuran, and then 1.3 mol of 1-hydroxybenzotriazole and 0.2 mol of N,N-dimethylpyridine were added and stirred in an ice-water bath for 30 min. Then, 1.2 mol of dicyclohexylcarbodiimide was added at room temperature and stirred vigorously for 12 h. The tetrahydrofuran was removed and concentrated under reduced pressure. 100 mL of ethyl acetate was added and stirred for 10 min. The ethyl acetate was removed under reduced pressure and purified to obtain intermediate 2.

[0033] Step A3: 1.03 mol of intermediate product 1 and 1 mol of intermediate product 2 were respectively stirred in 100 mL of dichloromethane, and recorded as solution 3 and solution 4, respectively. Under nitrogen conditions, solution 3 was slowly added dropwise to solution 4, and stirred at 35°C for 10 hours. The mixture was distilled and extracted under reduced pressure to obtain a corrosion-resistant modifier.

[0034] Example 2: The corrosion-resistant modifier is prepared by the following steps:

[0035] Step A1: 1 mol of N-allylaniline and 1.08 mol of isophorone diisocyanate were uniformly dispersed in 100 mL of dichloromethane, respectively designated as solution 1 and solution 2. Solution 2 was slowly added dropwise to solution 1 under nitrogen, and the mixture was stirred at room temperature for 10 h. The mixture was then distilled under reduced pressure and extracted to obtain intermediate product 1.

[0036] Step A2: 1 mol of allylaminoacetic acid hydrochloride was mixed and stirred in 100 mL of tetrahydrofuran, and then 1.4 mol of 1-hydroxybenzotriazole and 0.25 mol of N,N-dimethylpyridine were added and stirred in an ice-water bath for 30 min. Then, 1.3 mol of dicyclohexylcarbodiimide was added at room temperature and vigorously stirred for 14 h. The tetrahydrofuran was removed by concentration under reduced pressure, and 100 mL of ethyl acetate was added and stirred for 10 min. The ethyl acetate was then removed under reduced pressure and purified to obtain intermediate 2.

[0037] Step A3: 1.045 mol of intermediate product 1 and 1 mol of intermediate product 2 were respectively stirred in 100 mL of dichloromethane, and recorded as solution 3 and solution 4, respectively. Under nitrogen conditions, solution 3 was slowly added dropwise to solution 4, and stirred at 35 ° C for 12 h. The mixture was distilled and extracted under reduced pressure to obtain a corrosion-resistant modifier.

[0038] Example 3: The corrosion-resistant modifier is prepared by the following steps:

[0039] Step A1: 1 mol of N-allylaniline and 1.1 mol of isophorone diisocyanate were uniformly dispersed in 100 mL of dichloromethane, respectively, and recorded as solution 1 and solution 2. Under nitrogen, solution 2 was slowly added dropwise to solution 1, and the mixture was stirred at room temperature for 12 hours. The mixture was then distilled under reduced pressure and extracted to obtain intermediate product 1.

[0040] Step A2: 1 mol of allylaminoacetic acid hydrochloride was mixed and stirred in 100 mL of tetrahydrofuran, and then 1.5 mol of 1-hydroxybenzotriazole and 0.3 mol of N,N-dimethylpyridine were added and stirred in an ice-water bath for 30 min. Then, 1.4 mol of dicyclohexylcarbodiimide was added at room temperature and stirred vigorously for 16 h. The tetrahydrofuran was removed and concentrated under reduced pressure. 100 mL of ethyl acetate was added and stirred for 10 min. The ethyl acetate was removed under reduced pressure and purified to obtain intermediate 2.

[0041] Step A3: 1.06 mol of intermediate product 1 and 1 mol of intermediate product 2 were respectively stirred in 100 mL of dichloromethane, and recorded as solution 3 and solution 4, respectively. Under nitrogen conditions, solution 3 was slowly added dropwise to solution 4, and stirred at 35 ° C for 14 h. The mixture was distilled and extracted under reduced pressure to obtain a corrosion-resistant modifier.

[0042] Example 4: A method for preparing a water-sensitive photosensitive dry film comprises the following steps:

[0043] Step S1, weighing raw materials by weight, mixing 40 parts of waterborne polyurethane acrylate (solid content 70%), 8 parts of ethoxytris(hydroxymethyl)propane triacrylate, 4 parts of photoinitiator 369, 1.5 parts of the corrosion-resistant modifier prepared in Example 1, 1 part of KS66 defoamer, and 15 parts of water, and stirring them uniformly to obtain a photoresist;

[0044] Step S2: evenly coating a photoresist (with a thickness of 30 μm) on the surface of the PET film of the base layer and drying the same to obtain a photosensitive layer;

[0045] Step S3: Lay the protective polyethylene film on the surface of the photosensitive layer, and then cut, heat-seal, and roll it up to obtain a water-sensitive photosensitive dry film.

[0046] Example 5: A method for preparing a water-based photosensitive dry film comprises the following steps:

[0047] Step S1, weighing raw materials by weight, 50 parts of waterborne polyurethane acrylate (solid content 75%), 12 parts of ethoxytris(hydroxymethyl)propane triacrylate, 6 parts of photoinitiator 379, 2.5 parts of the corrosion-resistant modifier prepared in Example 2, 1.5 parts of KS66 defoamer, and 20 parts of water, and stirring them uniformly to obtain a photoresist;

[0048] Step S2: evenly coating a photoresist (with a thickness of 30 μm) on the surface of the PET film of the base layer and drying the same to obtain a photosensitive layer;

[0049] Step S3: Lay the protective polyethylene film on the surface of the photosensitive layer, and then cut, heat-seal, and roll it up to obtain a water-sensitive photosensitive dry film.

[0050] Example 6: A method for preparing a water-based photosensitive dry film comprises the following steps:

[0051] Step S1, weighing raw materials by weight, mixing 60 parts of waterborne polyurethane acrylate (solid content 80%), 15 parts of ethoxytris(hydroxymethyl)propane triacrylate, 8 parts of photoinitiator 379, 3.5 parts of the corrosion-resistant modifier prepared in Example 3, 2 parts of KS66 defoamer, and 25 parts of water, and stirring uniformly to obtain a photoresist;

[0052] Step S2: evenly coating a photoresist (with a thickness of 30 μm) on the surface of the PET film of the base layer and drying the same to obtain a photosensitive layer;

[0053] Step S3: Lay the protective polyethylene film on the surface of the photosensitive layer, and then cut, heat-seal, and roll it up to obtain a water-sensitive photosensitive dry film.

[0054] Comparative Example 1: This comparative example is a photosensitive dry film. The difference from Example 6 is that the commercially available corrosion inhibitor 1-hydroxybenzotriazole is used instead of the corrosion-resistant modifier prepared in Example 3. The rest are the same.

[0055] Comparative Example 2: This comparative example is a photosensitive dry film, which differs from Example 6 in that the corrosion-resistant modifier prepared in Example 3 is not added, and the rest are the same.

[0056] The photosensitive dry films prepared in Examples 4-6 and Comparative Examples 1-2 were laminated onto a copper plate using a laminator at 110° C. and a speed of 1.5 m / min, and allowed to stand for 30 minutes after lamination.

[0057] Adhesion test: After lamination, expose the film using a pattern with a line width and line spacing of n / 400 (unit: μm). Let it stand for 30 minutes. Develop it in a 1% wt sodium carbonate aqueous solution at 30°C for 1.5-2.0 times the minimum development time. Rinse and dry the film to remove the unexposed area. Observe the film under a microscope after development. The smaller the value, the better the adhesion.

[0058] Corrosion resistance test: After lamination, use a special electroplating pattern (dense line, independent line, circular pad) and expose with 20 grid energy. After development, rinse the copper plate with pure water, then let it stand in a degreaser for 10 minutes, and then use 3wt% dilute sulfuric acid for pickling. After pickling, put the copper plate into the electroplating solution (copper sulfate 65g / L, sulfuric acid 220g / L, chloride ion 60ppm, acid copper opener A is 12mL / L, acid copper brightener B is 3mL / L, opener 2mL / L), at room temperature, 20A / dm 2 Copper plating was carried out for 60 min under 400 nm, followed by water washing and drying. The electroplated copper plate was stripped and then observed by scanning electron microscopy for permeation plating.

[0059] Sensitivity test: After lamination, the sample was exposed using an LDI exposure machine (405nm wavelength). After exposure, it was left to stand for more than 30 minutes. The sample was sprayed with a 1%wt sodium carbonate aqueous solution at 30°C to remove the unexposed part. Under the same energy, the higher the number of grids remaining on the copper plate, the higher the sensitivity.

[0060] The test results are shown in Table 1:

[0061] Table 1: Performance test results

[0062]

[0063] As can be seen from Table 1, after the adhesion test, corrosion resistance test and sensitivity test, the photosensitive dry film prepared by the present invention has excellent adhesion, corrosion resistance and sensitivity.

[0064] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the scope of protection of the present invention.

Claims

1. A water-sensitive photosensitive dry film, characterized in that: From top to bottom, it includes a base layer, a photosensitive layer and a protective layer; the base layer is a PET film, the photosensitive layer is a photoresist, and the protective layer is a polyethylene film; The photoresist comprises the following raw materials in parts by weight: 40-60 parts of waterborne polyurethane acrylate, 8-15 parts of ethoxytrimethylolpropane triacrylate, 4-8 parts of photoinitiator, 1.5-3.5 parts of corrosion resistance modifier, 1-2 parts of defoaming agent, and 15-25 parts of water; The corrosion-resistant modifier is prepared by the following steps: Step A1: N-allylaniline and isophorone diisocyanate were uniformly dispersed in dichloromethane, respectively designated as solution 1 and solution 2. Solution 2 was slowly added dropwise to solution 1 under nitrogen, and the mixture was stirred at room temperature for 8-12 hours. The mixture was then distilled under reduced pressure and extracted to obtain intermediate product 1. Step A2: Allylaminoacetic acid hydrochloride was mixed and stirred in tetrahydrofuran, and 1-hydroxybenzotriazole and N,N-dimethylpyridine were added, and the mixture was stirred in an ice-water bath for 30 minutes. Dicyclohexylcarbodiimide was then added at room temperature, and the mixture was vigorously stirred for 12-16 hours. The tetrahydrofuran was removed by concentration under reduced pressure, and ethyl acetate was added and stirred for 10 minutes. The ethyl acetate was then removed under reduced pressure and purified to obtain intermediate 2. Step A3: The intermediate product 1 and the intermediate product 2 were respectively stirred in dichloromethane and recorded as solution 3 and solution 4, respectively. Under nitrogen conditions, solution 3 was slowly added dropwise to solution 4, and stirred at 35° C. for 10-14 hours. The mixture was distilled and extracted under reduced pressure to obtain a corrosion-resistant modifier.

2. The water-based photosensitive dry film according to claim 1, characterized in that: In step A1, the molar ratio of N-allylaniline to isophorone diisocyanate is 1:1.05-1.

1.

3. The water-based photosensitive dry film according to claim 1, characterized in that: In step A2, the molar ratio of allylaminoacetic acid hydrochloride, 1-hydroxybenzotriazole, N,N-dimethylpyridine and dicyclohexylcarbodiimide is 1:1.3-1.5:0.2-0.3:1.2-1.

4.

4. The water-based photosensitive dry film according to claim 1, characterized in that: In step A3, the molar ratio of intermediate product 1 to intermediate product 2 is 1.03-1.06:

1.

5. The water-based photosensitive dry film according to claim 1, characterized in that: The solid content of the waterborne polyurethane acrylate is 70%-80%.

6. The water-based photosensitive dry film according to claim 1, characterized in that: The photoinitiator is one of photoinitiator 369 or initiator 379.

7. The water-based photosensitive dry film according to claim 1, characterized in that: The defoamer is KS66 defoamer.

8. A method for preparing the water-based photosensitive dry film according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step S1, weighing raw materials in parts by weight, mixing waterborne polyurethane acrylate, ethoxytrimethylolpropane triacrylate, photoinitiator, corrosion resistance modifier, defoamer and water and stirring them uniformly to obtain a photoresist; Step S2: evenly coating the surface of the PET film of the base layer with a photoresist and drying the same to obtain a photosensitive layer; Step S3: Lay the protective polyethylene film on the photosensitive layer, and then cut, heat-seal, and roll it up to obtain a water-sensitive photosensitive dry film.

9. The method for preparing a water-based photosensitive dry film according to claim 8, wherein: The thickness of the photosensitive layer in step S2 is 30 μm.

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