Alkali-soluble resin as well as preparation method and application thereof

Abstract

The invention provides alkali-soluble resin as well as a preparation method and application thereof, the alkali-soluble resin is obtained by polymerizing polymeric monomers, and the polymeric monomers comprise a monomer as shown in a general formula (I), a monomer as shown in a general formula (II), a monomer as shown in a general formula (III) and a monomer as shown in a general formula (IV), the weight ratios of the monomers shown in the general formula (I) to the general formula (IV) in the polymerized monomers are respectively 15 to 35 weight percent, 40 to 75 weight percent, 5 to 35 weight percent and 0.1 to 15 weight percent. According to the alkali-soluble resin provided by the invention, a monomer containing a bridge ring structure is introduced into the structure, so that the adhesive force and the elasticity of a cured LDI photosensitive dry film are improved, the resolution ratio of the LDI photosensitive dry film is improved, and higher production efficiency of a printed circuit board is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of photosensitive materials and relates to an alkali-soluble resin and a preparation method and application thereof. Background Art

[0002] Photoresist is one of the core materials used in the electronic circuit industry for fine circuit processing. As electronic equipment develops towards miniaturization, thinness and high performance, higher and higher requirements are placed on photoresist materials. As the key to the formation of fine circuits in the manufacturing process of printed circuit boards, the comprehensive performance of photosensitive dry film is also constantly improving, such as high sensitivity, high resolution and high adhesion while maintaining an efficient film stripping rate.

[0003] The photosensitive dry film used in the manufacture of printed circuit boards generally includes pre-treatment, lamination, exposure, development, etching and film stripping. In the traditional exposure process of photosensitive dry film, a mercury lamp is used as the light source, which not only has high energy consumption, but also requires the pre-production of a mask. Compared with mercury lamp exposure, laser direct imaging (LDI) exposure is simpler and more efficient. It can avoid the difference in line width and line spacing caused by the instability of the mask, which is beneficial to improving product yield and production efficiency. Laser direct imaging exposure has high energy and has higher requirements on the comprehensive performance of photosensitive dry film. Existing LDI photosensitive dry film still has problems such as insufficient resolution, insufficient adhesion and poor anti-plating performance that need to be solved urgently.

[0004] Generally speaking, using a high molecular weight alkali-soluble resin in the photosensitive layer resin composition of the photosensitive dry film can improve its resolution, while using a low molecular weight resin is conducive to improving its adhesion. At the same time, functional groups that have a bonding effect with the copper surface can also be introduced to improve the adhesion between the dry film and the substrate. In order to improve the adhesion of the dry film resist, patent CN200480012068 introduces a phosphate group into the alkali-soluble resin, and CN201711228751 introduces a polymerizable monomer containing a cyclodextrin functional group into the resin composition. Both can improve the adhesion of the photosensitive dry film, but the effect is relatively limited.

[0005] Therefore, developing a photosensitive dry film resin with high resolution and strong adhesion has potential market value and application prospects. Summary of the invention

[0006] In view of the deficiencies of the prior art, the object of the present invention is to provide an alkali-soluble resin and a preparation method and application thereof.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In one aspect, the present invention provides an alkali-soluble resin, which is obtained by polymerizing monomers, wherein the polymerized monomers include a monomer represented by general formula (I), a monomer represented by general formula (II), a monomer represented by general formula (III) and a monomer represented by general formula (IV), and the weight proportions of the monomers represented by general formula (I) to general formula (IV) in the polymerized monomers are 15-35wt%, 40-75wt%, 5-35wt% and 0.1-15wt% respectively;

[0009]

[0010] Wherein, R1 is a hydrogen atom or a methyl group, R2 is a hydrogen atom or a methyl group, and R3 is a C1-C 18 R4 is a hydrogen atom or a methyl group, and R5 is a hydrogen atom, a C1-C5 alkyl group, a C1-C5 alkoxy group or R8 is a C1-C5 alkyl group; R6 is a hydrogen atom or a methyl group; R7 is a hydrogen atom or a methyl group; and n is any integer between 0 and 5 (eg, 0, 1, 2, 3, 4 or 5).

[0011] The alkali-soluble resin provided by the present invention introduces a monomer containing a bridge ring structure into the structure, which is beneficial to improving the adhesion and elasticity of the LDI photosensitive dry film after curing and improving its resolution, thereby achieving higher production efficiency of printed circuit boards.

[0012] In the present invention, the C1-C 18 The alkoxy group can be C1, C2, C3, C4, C6, C8, C 10 , C 12 , C 15 or C 18 The C1-C5 alkyl group may be a C1, C2, C3, C4 or C5 alkyl group, and the C1-C5 alkoxy group may be a C1, C2, C3, C4 or C5 alkoxy group.

[0013] Preferably, R3 is methoxy, ethoxy, propoxy, butoxy or tert-butoxy;

[0014] Preferably, R5 is a hydrogen atom, a methyl group, an ethyl group, a tert-butyl group, a methoxy group, an ethoxy group, a tert-butoxy group, a formyl group or an acetyl group.

[0015] In the present invention, the weight proportion of the monomer represented by general formula (I) in the polymerized monomer is 15-35wt%, for example, 15wt%, 18wt%, 20wt%, 22wt%, 25wt%, 28wt%, 30wt%, 33wt% or 35wt%.

[0016] In the present invention, the weight proportion of the monomer represented by the general formula (II) in the polymerized monomer is 40-75wt%, for example, 40wt%, 43wt%, 45wt%, 48wt%, 50wt%, 53wt%, 55wt%, 58wt%, 60wt%, 65wt%, 68wt%, 70wt%, 73wt% or 75wt%.

[0017] In the present invention, the weight proportion of the monomer represented by the general formula (III) in the polymerized monomer is 5-35wt%, for example, 5wt%, 8wt%, 10wt%, 13wt%, 15wt%, 18wt%, 20wt%, 22wt%, 25wt%, 28wt%, 30wt%, 33wt% or 35wt%.

[0018] In the present invention, the weight percentage of the monomer represented by general formula (IV) in the polymerized monomer is 1-15wt%, for example, 1wt%, 3wt%, 5wt%, 8wt%, 10wt%, 13wt% or 15wt%.

[0019] Preferably, the weight average molecular weight of the alkali soluble resin is in the range of 10,000-100,000, such as 10,000, 30,000, 50,000, 80,000 or 100,000. More preferably, the weight average molecular weight of the alkali soluble resin is in the range of 30,000-80,000.

[0020] Preferably, the molar ratio of the carboxyl functional group to the alicyclic functional group in the alkali-soluble resin is in the range of 1-30:1.

[0021] Further preferably, the molar ratio of the carboxyl functional group to the cyclic functional group in the alkali-soluble resin is in the range of 4-20:1.

[0022] On the other hand, the present invention provides a method for preparing the alkali-soluble resin as described above, the preparation method comprising the following steps:

[0023] The monomer represented by the general formula (I), the monomer represented by the general formula (II), the monomer represented by the general formula (III) and the monomer represented by the general formula (IV) are polymerized in the presence of a catalyst to obtain the alkali-soluble resin.

[0024] Preferably, the catalyst is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile and dimethyl azobisisobutyrate.

[0025] Preferably, the polymerization reaction is carried out in an organic solvent, and the organic solvent is selected from one or more of butanone, ethanol, isopropanol, methanol, propylene glycol methyl ether, butyl acetate, and acetone.

[0026] Preferably, the polymerization reaction temperature is 60-100°C, for example 60°C, 65°C, 68°C, 70°C, 75°C, 78°C, 80°C, 85°C, 90°C, 95°C or 100°C.

[0027] Preferably, the polymerization reaction time is 6 to 10 hours.

[0028] In another aspect, the present invention provides a photosensitive resin composition, comprising the alkali-soluble resin as described above.

[0029] Preferably, the photosensitive resin composition further comprises a polymerizable monomer, an initiator, an additive and an organic solvent.

[0030] Preferably, the photosensitive resin composition comprises the following components in parts by weight:

[0031]

[0032] In the present invention, the content of the alkali-soluble resin in the photosensitive resin composition is 30 parts, 35 parts, 38 parts, 40 parts, 45 parts, 48 ​​parts, 50 parts, 55 parts, 58 parts or 60 parts.

[0033] In the present invention, the content of the polymerizable monomer in the photosensitive resin composition is 25 parts, 30 parts, 35 parts, 38 parts, 40 parts, 45 parts, 48 ​​parts or 50 parts.

[0034] In the present invention, the content of the initiator in the photosensitive resin composition is 0.1 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts.

[0035] In the present invention, the content of the additive in the photosensitive resin composition is 0.1 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts.

[0036] In the present invention, the content of the organic solvent in the photosensitive resin composition is 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 70 parts, 80 parts, 90 parts or 100 parts.

[0037] Preferably, the polymerizable monomer is at least one of polyurethane acrylate, bisphenol A diacrylate, ethoxylated bisphenol A diacrylate, propoxylated bisphenol A diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, nonylphenol acrylate, trimethylolpropane triacrylate or isooctyl acrylate.

[0038] Preferably, the initiator is at least one of benzophenone derivatives, thioxanthone compounds, thioxanthone series compounds or hexaarylbiimidazole series compounds.

[0039] Preferably, the additive includes at least one of an inhibitor, a plasticizer, a leveling agent, a defoaming agent or a dye;

[0040] Preferably, the organic solvent comprises at least one of butanone, acetone, isopropanol, toluene, butyl acetate, propylene glycol monomethyl ether or propylene glycol methyl ether acetate.

[0041] In another aspect, the present invention provides a photosensitive dry film, which is prepared from the photosensitive resin composition described above.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The alkali-soluble resin provided by the present invention introduces a monomer containing a bridge ring structure into the structure, which is beneficial to improving the adhesion and elasticity of the LDI photosensitive dry film after curing and improving its resolution, thereby achieving higher production efficiency of printed circuit boards. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0045] Alkali soluble resin synthesis

[0046] Synthesis Example 1: Synthesis of Alkali-Soluble Resin Polymer A1

[0047] To a four-necked flask equipped with an electric stirrer, a thermometer, a constant pressure dropping funnel and a condenser, methacrylic acid, methyl methacrylate, styrene and acrylate ester in a mass ratio of 27g:40g:26g:7g were added, 110g of butanone was added, mixed thoroughly, nitrogen was passed through for 5 minutes under stirring, and then placed in an oil bath and heated to 80°C, 0.8g of azobisisobutyronitrile was dissolved in 40g of butanone, and the mixture was slowly dripped into the above mixed solution through a constant pressure dropping funnel, and the dripping was completed within 2 hours, and then the reaction was continued at 80°C for 4 hours. The reaction was terminated by natural cooling to obtain an alkali-soluble resin solution A1, and its weight average molecular weight Mw=49000 and PDI=1.7 were obtained by GPC test.

[0048] Synthesis Example 2: Synthesis of Alkali-Soluble Resin Polymer A2

[0049] To a four-necked flask equipped with an electric stirrer, a thermometer, a constant pressure dropping funnel and a condenser, add methacrylic acid, methyl methacrylate, styrene and acrylate in a mass ratio of 27g:40g:26g:7g, add 110g of butanone, mix thoroughly, pass nitrogen under stirring for 5 minutes, then place it in an oil bath and heat it to 80°C, dissolve 1.5g of azobisisobutyronitrile in 40g of butanone, and slowly drip it into the above mixed solution through a constant pressure dropping funnel, and complete the dripping within 2 hours, and then continue to keep warm at 80°C for 4 hours, and naturally cool to terminate the reaction, so as to obtain an alkali-soluble resin solution A2, and its weight average molecular weight Mw=31000 and PDI=1.8 are obtained by GPC test.

[0050] Synthesis Example 3: Synthesis of Alkali-Soluble Resin Polymer A3

[0051] To a four-necked flask equipped with an electric stirrer, a thermometer, a constant pressure dropping funnel and a condenser, add methacrylic acid, methyl methacrylate, styrene and acrylate in a mass ratio of 27g:40g:26g:7g, add 110g of butanone, mix thoroughly, pass nitrogen under stirring for 5 minutes, then place it in an oil bath and heat it to 80°C, dissolve 0.4g of azobisisobutyronitrile in 40g of butanone, and slowly drip it into the above mixed solution through a constant pressure dropping funnel, and complete the dripping within 4 hours, and then continue to keep warm at 80°C for 4 hours, and naturally cool to terminate the reaction, so as to obtain an alkali-soluble resin solution A3, and its weight average molecular weight Mw=62000 and PDI=2.0 are obtained by GPC test.

[0052] Synthesis Example 4: Synthesis of Alkali-Soluble Resin Polymer A4

[0053] To a four-necked flask equipped with an electric stirrer, a thermometer, a constant pressure dropping funnel and a condenser, methacrylic acid, methyl methacrylate, styrene and acrylate ester in a mass ratio of 27g:48g:22g:3g were added, 110g of butanone was added, mixed thoroughly, nitrogen was passed through for 5 minutes under stirring, and then placed in an oil bath and heated to 80°C, 0.8g of azobisisobutyronitrile was dissolved in 40g of butanone, and the mixture was slowly dripped into the mixed solution through a constant pressure dropping funnel, and the mixture was dripped within 2 hours, and then the reaction was continued at 80°C for 4 hours. The reaction was terminated by natural cooling to obtain an alkali-soluble resin solution A4, and its weight average molecular weight Mw=64000 and PDI=1.8 were obtained by GPC test.

[0054] Synthesis Example 5: Synthesis of Alkali-Soluble Resin Polymer A5

[0055] To a four-necked flask equipped with an electric stirrer, a thermometer, a constant pressure dropping funnel and a condenser, methacrylic acid, methyl methacrylate, styrene and acrylate in a mass ratio of 27g:48g:22g:3g were added, 100g of propylene glycol methyl ether was added, the mixture was fully mixed, nitrogen was passed through for 5 minutes under stirring, and then the mixture was placed in an oil bath and heated to 90°C, 0.6g of azobisisobutyronitrile was dissolved in 30g of butanone, and the mixture was slowly dripped into the mixed solution through a constant pressure dropping funnel, and the mixture was dripped within 30 minutes, and then the mixture was kept warm for 3 hours at 90°C, and then 0.2g of azobisisobutyronitrile was dissolved in 20g of butanone, and the mixture was dripped into the reaction system within 30 minutes, and the mixture was kept warm for 2 hours, and then the reaction was terminated by natural cooling, thereby obtaining an alkali-soluble resin solution A5, and its weight average molecular weight Mw=55000 and PDI=2.1 were obtained by GPC test.

[0056] Synthesis Example 6: Synthesis of Alkali-Soluble Resin Polymer A6

[0057] To a four-necked flask equipped with an electric stirrer, a thermometer, a constant pressure dropping funnel and a condenser, methacrylic acid, methyl methacrylate, styrene and butyl methacrylate in a mass ratio of 27g:40g:26g:7g were added, 110g of butanone was added, mixed thoroughly, nitrogen was passed through for 5 minutes under stirring, and then placed in an oil bath and heated to 80°C, 0.8g of azobisisobutyronitrile was dissolved in 40g of butanone, and the mixture was slowly dripped into the mixed solution through a constant pressure dropping funnel, and the mixture was dripped within 2 hours, and then the reaction was continued at 80°C for 4 hours. The reaction was terminated by natural cooling to obtain an alkali-soluble resin solution A5, and its weight average molecular weight Mw=51000 and PDI=1.8 were obtained by GPC test.

[0058] Preparation of resin composition:

[0059] According to the mass ratio shown in Table 1 below, the resin compositions of the examples and comparative examples were prepared.

[0060] Table 1

[0061]

[0062]

[0063] In Table 1, B1 is ethoxylated bisphenol A diacrylate, B2 is hexanediol diacrylate, B3 is trimethylolpropane triacrylate, C1 is 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbisimidazole, C2 is 9-phenylacridine, and C3 is N-phenylglycine.

[0064] Preparation of photosensitive dry film:

[0065] The resin compositions of the above embodiments and comparative examples were respectively coated on 18 μm high-transmittance polyester (PET) films, the coated films were dried at 40°C for 3 min, then dried at 90°C for 2 min, and after cooling, a layer of polyethylene film was applied as a protective film to obtain a photosensitive dry film, and the thickness of the photosensitive resin composition layer was 38 μm.

[0066] The photosensitive dry film prepared from the resin composition was tested to evaluate its sensitivity, resolution and fine line adhesion. The evaluation results are shown in Table 2.

[0067] Sensitivity evaluation:

[0068] The polyethylene protective film was removed from the photosensitive dry film in the embodiment and the comparative example, and the photosensitive dry film was attached to the copper-clad board by a laminator at 110°C at a speed of 1.5 m / min to obtain a test board. A Stouffer 21-step exposure scale was placed on the dry film layer of the test board for sensitivity testing. Then, the photosensitive dry film was exposed to light using a laser exposure machine with a wavelength of 405 nm. The PET film was then peeled off and spray-developed at 30°C using a 1% by mass sodium carbonate aqueous solution. After removing the unexposed part, the number of steps of the exposure scale under a specific exposure energy was set as the sensitivity. The results are listed in Table 2.

[0069] Resolution evaluation:

[0070] In the same manner as the above sensitivity, a photosensitive dry film was attached to a copper-clad laminate to prepare a test board, and an LDI exposure machine was used to expose the test board at a specific exposure energy, wherein the wiring ratio of the exposed part to the non-exposed part was 1:1. Then, the PET film was peeled off, and a 1% by mass sodium carbonate aqueous solution was sprayed for development at 30°C for 40 seconds. The minimum spacing between the line widths of the completely removed non-exposed part was observed under a digital microscope and evaluated as the resolution value. The smaller the value, the better the result. These values ​​are recorded in Table 2.

[0071] Fine line adhesion evaluation:

[0072] In the same manner as the above sensitivity, a photosensitive dry film was attached to a copper-clad laminate to prepare a test board, and an LDI exposure machine was used to expose the test board at a specific exposure energy, wherein the wiring ratio of the exposed part to the non-exposed part was 5:1. Then, the PET film was peeled off, and a 1% by mass sodium carbonate aqueous solution was used for spray development at 30°C for 40 seconds. The minimum line width when the non-exposed part was completely removed was observed using a digital microscope and evaluated as the value of fine line adhesion. The smaller the value, the better the result. These values ​​are recorded in Table 2.

[0073] Table 2

[0074]

[0075] As shown in Table 2, compared with the comparative example, the embodiment has better sensitivity, resolution and fine line adhesion.

[0076] The applicant declares that the present invention illustrates the alkali-soluble resin and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An alkali-soluble resin, It is characterized in that The alkali-soluble resin is obtained by polymerizing monomers, wherein the polymerized monomers include a monomer represented by general formula (I), a monomer represented by general formula (II), a monomer represented by general formula (III) and a monomer represented by general formula (IV), and the weight proportions of the monomers represented by general formula (I) to general formula (IV) in the polymerized monomers are 15-35wt%, 40-75wt%, 5-35wt% and 0.1-15wt% respectively; Among them, R 1 is a hydrogen atom or a methyl group, R 2 is a hydrogen atom or a methyl group, R 3 C 1 -C 18 The alkoxy group, R 4 is a hydrogen atom or a methyl group, R 5 is a hydrogen atom, a C1-C5 alkyl group, a C1-C5 alkoxy group or R 8 is a C1-C5 alkyl group; R 6 is a hydrogen atom or a methyl group, R 7 is a hydrogen atom or a methyl group, and n is any integer between 0 and 5.

2. The alkali-soluble resin according to claim 1, It is characterized in that R 3 is methoxy, ethoxy, propoxy, butoxy or tert-butoxy; Preferably, R 5 It is a hydrogen atom, a methyl group, an ethyl group, a tert-butyl group, a methoxy group, an ethoxy group, a tert-butoxy group, a formyl group or an acetyl group.

3. The alkali-soluble resin according to claim 1 or 2, It is characterized in that The weight average molecular weight of the alkali soluble resin is in the range of 10,000-100,000, preferably 30,000-80,000.

4. The alkali-soluble resin according to any one of claims 1 to 3, It is characterized in that The molar ratio of the carboxyl functional group to the alicyclic functional group in the alkali-soluble resin is in the range of 1-30:1, preferably 4-20:

1.

5. The alkali-soluble resin according to any one of claims 1 to 4, It is characterized in that The preparation method comprises the following steps: The monomer represented by the general formula (I), the monomer represented by the general formula (II), the monomer represented by the general formula (III) and the monomer represented by the general formula (IV) are polymerized in the presence of a catalyst to obtain the alkali-soluble resin.

6. The preparation method according to claim 5, It is characterized in that The catalyst is selected from one or a combination of at least two of azobisisobutyronitrile, azobisisoheptanenitrile and dimethyl azobisisobutyrate; Preferably, the polymerization reaction is carried out in an organic solvent, and the organic solvent is selected from one or more of butanone, ethanol, isopropanol, methanol, propylene glycol methyl ether, butyl acetate, and acetone; Preferably, the polymerization reaction temperature is 60-100°C; Preferably, the polymerization reaction time is 6 to 10 hours.

7. A photosensitive resin composition, It is characterized in that The photosensitive resin composition comprises the alkali-soluble resin according to any one of claims 1 to 4.

8. The photosensitive resin composition according to claim 7, It is characterized in that The photosensitive resin composition further comprises a polymerizable monomer, an initiator, an additive and an organic solvent; Preferably, the photosensitive resin composition comprises the following components in parts by weight:

9. The photosensitive resin composition according to claim 7 or 8, It is characterized in that The polymerizable monomer is at least one of polyurethane acrylate, bisphenol A diacrylate, ethoxylated bisphenol A diacrylate, propoxylated bisphenol A diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, nonylphenol acrylate, trimethylolpropane triacrylate, hexanediol diacrylate, pentanediol diacrylate or butanediol diacrylate; Preferably, the initiator is at least one of benzophenone derivatives, acridine compounds, thioxanthone compounds, thioxanthone series compounds or hexaarylbiimidazole series compounds; Preferably, the additive includes at least one of an inhibitor, a plasticizer, a leveling agent, a defoaming agent or a dye; Preferably, the organic solvent comprises at least one of butanone, acetone, toluene, butyl acetate or propylene glycol monomethyl ether.

10. A photosensitive dry film, wherein the photosensitive dry film is prepared from the photosensitive resin composition according to any one of claims 7 to 9.

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