Water-based photosensitive dry film and preparation method thereof

Abstract

The invention relates to the technical field of photosensitive materials, and discloses a water-based photosensitive dry film and a preparation method thereof. The prepared water-based photosensitive dry film sequentially comprises a base layer, a photosensitive layer and a protective layer from top to bottom, 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, and the photoresist is prepared by taking waterborne polyurethane acrylate as a main raw material and adding auxiliaries such as a photoinitiator, a corrosion-resistant modifier and a cross-linking agent; the photoresist has excellent adhesive force, corrosion resistance and photosensitive property.

Description

Technical Field

[0001] The present invention relates to the technical field of photosensitive materials, and particularly relates to an aqueous photosensitive dry film and a preparation method thereof. Background Art

[0002] Photoresist Dry Film is a core material in the manufacturing of printed circuit boards (PCBs), mainly used for the graphic transfer process, and forms an anti-etching or anti-electroplating mask pattern through exposure and development. Traditional solvent-based photoresist dry films have problems such as volatile organic compound emissions, flammability and explosiveness, and environmental pollution due to the use of organic solvents (such as acetone and ethyl acetate). With the increasingly strict global environmental protection regulations, aqueous photosensitive dry films have become the key development direction in the industry due to their characteristics of using water as the dispersion medium and being low-toxic and environmentally friendly.

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

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

[0005] The object of the present invention can be achieved by the following technical solutions: An aqueous photosensitive dry film, which sequentially includes a base layer, a photosensitive layer and a protective layer from top to bottom; the base layer is a PET film, the photosensitive layer is a photoresist, and the protective layer is a polyethylene film; Further, the photoresist includes the following raw materials in parts by weight: 40-60 parts of aqueous polyurethane acrylate, 8-15 parts of ethoxylated trimethylolpropane triacrylate, 4-8 parts of photoinitiator, 1.5-3.5 parts of corrosion-resistant modifier, 1-2 parts of defoamer, and 15-25 parts of water; Further, the solid content of the aqueous polyurethane acrylate is 50%-60%; Further, the photoinitiator is one of photoinitiator 369 or initiator 379; Further, the defoamer is KS66 defoamer; The corrosion-resistant modifier is prepared by the following steps: Step A1: Disperse N-allylaniline and isophorone diisocyanate evenly in dichloromethane respectively, and record them as Solution 1 and Solution 2. Under the condition of nitrogen, slowly drop Solution 2 into Solution 1, and stir and react at room temperature for 8 - 12 h. Then perform vacuum distillation and extraction to obtain Intermediate Product 1. Further, in Step A1, the molar ratio of N-allylaniline to isophorone diisocyanate is 1:1.05 - 1.1. Further, Step A1 is to react the -NH group in N-allylaniline with one -NCO group in isophorone diisocyanate to obtain Intermediate Product 1 containing a blocked urea bond. Step A2: Mix and stir allyl glycine hydrochloride evenly in tetrahydrofuran, then add 1-hydroxybenzotriazole and N,N-dimethylpyridine, and stir for 30 min in an ice-water bath. Then add dicyclohexylcarbodiimide at room temperature and stir vigorously for 12 - 16 h. Concentrate under reduced pressure to remove tetrahydrofuran, add ethyl acetate and stir for 10 min, then remove ethyl acetate under reduced pressure and purify to obtain Intermediate Product 2. Further, in Step A2, the molar ratio of allyl glycine hydrochloride, 1-hydroxybenzotriazole, N,N-dimethylpyridine to dicyclohexylcarbodiimide is 1:1.3 - 1.5:0.2 - 0.3:1.2 - 1.4. Further, Step A2 is to react the carboxyl group in allyl glycine hydrochloride with the hydroxyl group in 1-hydroxybenzotriazole to obtain Intermediate Product 2 containing a benzotriazole structure and a secondary amine structure. Step A3: Stir Intermediate Product 1 and Intermediate Product 2 evenly in dichloromethane respectively, and record them as Solution 3 and Solution 4. Under the condition of nitrogen, slowly drop Solution 3 into Solution 4, and stir at 35 °C for 10 - 14 h. Then perform vacuum distillation and extraction to obtain the corrosion-resistant modifier. Further, in Step A3, the molar ratio of Intermediate Product 1 to Intermediate Product 2 is 1.03 - 1.06:1. Further, Step A3 is to react the remaining -NCO group in Intermediate Product 1 with the secondary amine structure in Intermediate Product 2 to obtain the corrosion-resistant modifier.

[0006] A preparation method of a water-based photosensitive dry film includes the following steps: Step S1: Weigh raw materials by weight parts, mix and stir evenly aqueous polyurethane acrylate, ethoxylated trimethylolpropane triacrylate, photoinitiator, corrosion-resistant modifier, defoamer and water to obtain a photoresist. Step S2: Uniformly coat the photoresist on the surface of a base PET film and dry it to obtain a photosensitive layer. Further, in Step S2, the thickness of the photosensitive layer is 30 μm. Step S3: Stick the polyethylene film of the protective layer onto the photosensitive layer, and then through slitting, heat sealing and winding, the water-based photosensitive dry film is obtained.

[0007] Beneficial effects of the present invention: 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. The photoresist is prepared by using water-based polyurethane acrylate as the main raw material and adding auxiliaries such as a photoinitiator, a corrosion-resistant modifier and a cross-linking agent (ethoxylated trimethylolpropane triacrylate), etc. The photoresist has excellent adhesion, corrosion resistance and photosensitive properties. Among them, the corrosion-resistant modifier improves the corrosion resistance of the photosensitive layer, enables it to stably adhere to the surface of the copper plate, plays a role in blocking electroplating and etching, and also has environmental friendliness.

[0008] The corrosion-resistant modifier introduced in the preparation of the photoresist of the present invention improves the adhesion of the photoresist to the copper plate and its own corrosion resistance. The benzotriazole structure introduced in the corrosion-resistant modifier can form a coordination bond with the surface of the copper plate by using the N atom contained therein to generate a stable complex protective film, preventing the direct contact between copper and the etching solution and inhibiting the corrosion reaction. At the same time, the generation of the complex also improves the adhesion between the photosensitive dry film and the copper plate. The hindered urea bond is a benzene ring structure with steric hindrance on one side of the urea bond. The steric hindrance effect of the hindered urea bond restricts the free movement of the polymer molecular chain in the photosensitive dry film, promotes the polymer to form a dense cross-linked network, can effectively block the penetration of the etching solution (such as acidic or alkaline solution), improves the chemical corrosion resistance, and at the same time, the -NH group in the urea bond can also form a hydrogen bond with the surface oxide of the copper substrate to enhance the adhesion between the photoresist and the substrate and prevent the film layer from peeling off during the pattern transfer process. In addition, the double bond structure introduced in the corrosion-resistant modifier can participate in the reaction during the subsequent exposure process, so that it is firmly fixed on the copper plate by chemical bonding, effectively avoiding the reduction of corrosion resistance caused by the easy migration of traditional small molecule corrosion inhibitors in the exposed photosensitive dry film. At the same time, the presence of hydrophilic groups enables it to be evenly dispersed in water. Specific embodiments

[0009] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0010] Example 1: The corrosion-resistant modifier is prepared by the following steps: Step A1: Disperse 1 mol of N-allylaniline and 1.05 mol of isophorone diisocyanate evenly in 100 mL of dichloromethane respectively, and mark them as Solution 1 and Solution 2. Under nitrogen conditions, slowly add Solution 2 to Solution 1, and stir and react at room temperature for 8 h. Then perform vacuum distillation and extraction to obtain Intermediate 1; Step A2: Mix and stir 1 mol of allylglycine hydrochloride evenly in 100 mL of tetrahydrofuran, then add 1.3 mol of 1-hydroxybenzotriazole and 0.2 mol of N,N-dimethylpyridine, and stir in an ice-water bath for 30 min. Then add 1.2 mol of dicyclohexylcarbodiimide at room temperature and stir vigorously for 12 h. Concentrate under reduced pressure to remove tetrahydrofuran, add 100 mL of ethyl acetate and stir for 10 min, then remove ethyl acetate under reduced pressure and purify to obtain Intermediate 2; Step A3: Stir 1.03 mol of Intermediate 1 and 1 mol of Intermediate 2 evenly in 100 mL of dichloromethane respectively, and mark them as Solution 3 and Solution 4. Under nitrogen conditions, slowly add Solution 3 to Solution 4, and stir at 35 °C for 10 h. Then perform vacuum distillation and extraction to obtain the corrosion-resistant modifier.

[0011] Example 2: The corrosion-resistant modifier is prepared by the following steps: Step A1: Disperse 1 mol of N-allylaniline and 1.08 mol of isophorone diisocyanate evenly in 100 mL of dichloromethane respectively, and mark them as Solution 1 and Solution 2. Under nitrogen conditions, slowly add Solution 2 to Solution 1, and stir and react at room temperature for 10 h. Then perform vacuum distillation and extraction to obtain Intermediate 1; Step A2: Mix and stir 1 mol of allylglycine hydrochloride evenly in 100 mL of tetrahydrofuran, then add 1.4 mol of 1-hydroxybenzotriazole and 0.25 mol of N,N-dimethylpyridine, and stir in an ice-water bath for 30 min. Then add 1.3 mol of dicyclohexylcarbodiimide at room temperature and stir vigorously for 14 h. Concentrate under reduced pressure to remove tetrahydrofuran, add 100 mL of ethyl acetate and stir for 10 min, then remove ethyl acetate under reduced pressure and purify to obtain Intermediate 2; Step A3: Stir 1.045 mol of Intermediate 1 and 1 mol of Intermediate 2 evenly in 100 mL of dichloromethane respectively, and mark them as Solution 3 and Solution 4. Under nitrogen conditions, slowly add Solution 3 to Solution 4, and stir at 35 °C for 12 h. Then perform vacuum distillation and extraction to obtain the corrosion-resistant modifier.

[0012] Example 3: The corrosion-resistant modifier is prepared by the following steps: Step A1: Disperse 1 mol of N-allylaniline and 1.1 mol of isophorone diisocyanate evenly in 100 mL of dichloromethane respectively, and mark them as Solution 1 and Solution 2. Under the condition of nitrogen, slowly drop Solution 2 into Solution 1, and stir and react at room temperature for 12 h. Then, perform reduced-pressure distillation and extraction to obtain Intermediate Product 1. Step A2: Mix and stir 1 mol of allylglycine hydrochloride evenly in 100 mL of tetrahydrofuran, then add 1.5 mol of 1-hydroxybenzotriazole and 0.3 mol of N,N-dimethylpyridine, and stir for 30 min in an ice-water bath. Then, add 1.4 mol of dicyclohexylcarbodiimide at room temperature and stir vigorously for 16 h. Concentrate under reduced pressure to remove tetrahydrofuran, add 100 mL of ethyl acetate and stir for 10 min, then remove ethyl acetate under reduced pressure and purify to obtain Intermediate Product 2. Step A3: Stir 1.06 mol of Intermediate Product 1 and 1 mol of Intermediate Product 2 evenly in 100 mL of dichloromethane respectively, and mark them as Solution 3 and Solution 4. Under the condition of nitrogen, slowly drop Solution 3 into Solution 4, and stir at 35 °C for 14 h. Then, perform reduced-pressure distillation and extraction to obtain the corrosion-resistant modifier.

[0013] Example 4: A preparation method of a water-based photosensitive dry film includes the following steps: Step S1: Weigh the raw materials by weight. Mix 40 parts of water-based polyurethane acrylate (solid content 70%), 8 parts of ethoxylated trimethylolpropane 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 evenly by stirring to obtain the photoresist. Step S2: Uniformly coat the photoresist (with a thickness of 30 μm) on the surface of the base PET film and dry it to obtain the photosensitive layer. Step S3: Stick the polyethylene film of the protective layer on the surface of the photosensitive layer, and then perform slitting, heat sealing and winding to obtain the water-based photosensitive dry film.

[0014] Example 5: A preparation method of a water-based photosensitive dry film includes the following steps: Step S1: Weigh the raw materials by weight. Mix 50 parts of water-based polyurethane acrylate (solid content 75%), 12 parts of ethoxylated trimethylolpropane 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 evenly by stirring to obtain the photoresist. Step S2: Uniformly coat the photoresist (with a thickness of 30 μm) on the surface of the base PET film and dry it to obtain the photosensitive layer. Step S3: Stick the polyethylene film of the protective layer on the surface of the photosensitive layer, and then perform slitting, heat sealing and winding to obtain the water-based photosensitive dry film.

[0015] Example 6: A preparation method of an aqueous photosensitive dry film includes the following steps: Step S1: Weigh raw materials by weight. Mix 60 parts of aqueous polyurethane acrylate (solid content 80%), 15 parts of ethoxylated trimethylolpropane 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 stir evenly to obtain a photoresist; Step S2: Uniformly coat the photoresist (with a thickness of 30 μm) on the surface of the base PET film and dry it to obtain a photosensitive layer; Step S3: Stick a polyethylene film of the protective layer on the surface of the photosensitive layer, and then perform slitting, heat sealing, and winding to obtain an aqueous photosensitive dry film.

[0016] Comparative Example 1: This comparative example is a photosensitive dry film. The difference from Example 6 is that a commercially available corrosion inhibitor 1-hydroxybenzotriazole is used instead of the corrosion-resistant modifier prepared in Example 3, and the rest are the same.

[0017] Comparative Example 2: This comparative example is a photosensitive dry film. The difference from Example 6 is that the corrosion-resistant modifier prepared in Example 3 is not added, and the rest are the same.

[0018] Press the photosensitive dry films prepared in Examples 4-6 and Comparative Examples 1-2 onto a copper plate using a laminator at a temperature of 110 °C and a speed of 1.5 m / min, and let it stand for 3 min after pressing; Adhesion test: After pressing, use a pattern with a line width and line spacing of n / 400 (unit: um) for exposure, let it stand for 30 min, develop in a 1%wt sodium carbonate aqueous solution at 30 °C, with the development time being 1.5 - 2.0 times the minimum development time, then wash with water, dry, remove the unexposed area, and observe with a microscope after development. The smaller the value read, the better the adhesion; Corrosion resistance test: After pressing, use a special pattern for electroplating (dense lines, independent lines, circular pads), expose with 20 grids of energy, after development, wash the copper plate with pure water, then let it stand in a degreaser for 10 min, then pickle it with 3wt% dilute sulfuric acid, and after pickling, put the copper plate into an electroplating solution (copper sulfate 65 g / L, sulfuric acid 220 g / L, chloride ions 60 ppm, acid copper starter A 12 mL / L, acid copper brightener B 3 mL / L, starter 2 mL / L), at room temperature, 20 A / dm 2 for copper plating for 60 min, then wash and dry, after removing the film from the electroplated copper plate, use a scanning electron microscope to observe for infiltration plating; Sensitivity test: After laminating, the sample is exposed using an LDI exposure machine (wavelength 405 nm). After exposure, it is left standing for more than 30 minutes. Then, the sample is sprayed with a 1% wt sodium carbonate aqueous solution at 30 °C to remove the unexposed part. At the same energy, the higher the number of grids remaining on the copper plate, the higher the sensitivity.

[0019] The test results are shown in Table 1: Table 1: Performance test results

[0020] As can be seen from Table 1, after the adhesion test, corrosion resistance test, and sensitivity test of the photosensitive dry film prepared by the present invention, the photosensitive dry film has excellent adhesion, corrosion resistance, and sensitivity.

[0021] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the specific embodiments described or use similar methods for substitution, as long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. An aqueous photosensitive dry film, characterized in that, It includes a base layer, a photosensitive layer, and a protective layer in sequence from top to bottom; the base layer is a PET film, the photosensitive layer is a photoresist, and the protective layer is a polyethylene film; The photoresist includes the following raw materials in parts by weight: 40 - 60 parts of waterborne polyurethane acrylate, 8 - 15 parts of ethoxylated trimethylolpropane triacrylate, 4 - 8 parts of photoinitiator, 1.5 - 3.5 parts of corrosion-resistant modifier, 1 - 2 parts of defoamer, and 15 - 25 parts of water; The corrosion-resistant modifier is prepared by reacting intermediate product 1 and intermediate product 2. Intermediate product 1 is prepared by reacting N-allylaniline and isophorone diisocyanate, and intermediate product 2 is prepared by reacting allylaminoacetic acid hydrochloride and 1-hydroxybenzotriazole.

2. The water-based photosensitive dry film according to claim 1, characterized in that, The corrosion-resistant modifier is prepared by the following steps: Step A1: Disperse N-allylaniline and isophorone diisocyanate evenly in dichloromethane respectively, and record them as solution 1 and solution 2. Under nitrogen condition, slowly drip solution 2 into solution 1, and stir and react at room temperature for 8 - 12 h, then carry out vacuum distillation and extraction to obtain intermediate product 1; Step A2: Mix and stir allylaminoacetic acid hydrochloride evenly in tetrahydrofuran, then add 1-hydroxybenzotriazole and N,N-dimethylpyridine, and stir in an ice-water bath for 30 min. Then add dicyclohexylcarbodiimide at room temperature and stir vigorously for 12 - 16 h. Concentrate under reduced pressure to remove tetrahydrofuran, add ethyl acetate and stir for 10 min, then remove ethyl acetate under reduced pressure and purify to obtain intermediate product 2; Step A3: Stir intermediate product 1 and intermediate product 2 evenly in dichloromethane respectively, and record them as solution 3 and solution 4. Under nitrogen condition, slowly drip solution 3 into solution 4, and stir at 35 °C for 10 - 14 h, then carry out vacuum distillation and extraction to obtain the corrosion-resistant modifier.

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

1.

4. The aqueous photosensitive dry film according to claim 2, wherein In step A2, the molar ratio of allylaminoacetic acid hydrochloride, 1-hydroxybenzotriazole, N,N-dimethylpyridine to dicyclohexylcarbodiimide is 1:1.3 - 1.5:0.2 - 0.3:1.2 - 1.

4.

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

1.

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

7. A water-based photosensitive dry film according to claim 1, wherein The photoinitiator is one of photoinitiator 369 or initiator 379.

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

9. The preparation method of the aqueous photosensitive dry film according to any one of claims 1-8, characterized in that, It includes the following steps: Step S1: Weigh the raw materials by parts by weight, mix and stir evenly waterborne polyurethane acrylate, ethoxylated trimethylolpropane triacrylate, photoinitiator, corrosion-resistant modifier, defoamer and water to obtain the photoresist; Step S2: Uniformly coat the photoresist on the surface of the PET film of the base layer and dry it to obtain the photosensitive layer; Step S3: Stick the polyethylene film of the protective layer on the photosensitive layer, and then carry out slitting, heat sealing and winding to obtain the water-based photosensitive dry film.

10. The preparation method of the aqueous photosensitive dry film according to claim 9, characterized in that, In step S2, the thickness of the photosensitive layer is 30 μm.

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