阅读说明：本技术 一种高附着耐电镀感光干膜抗蚀剂 (High-adhesion electroplating-resistant photosensitive dry film resist ) 是由 袁丽 朱高华 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种高附着耐电镀感光干膜抗蚀剂,组分包括45~65重量份的碱可溶性共聚物树脂、30~50重量份的光聚合单体、0.1~4.0重量份光引发剂、0.1~5.0重量份的其它添加剂；所述碱可溶性共聚物树脂是由结构通式为(Ⅰ)的第一单体,与结构通式为(Ⅱ)的第二单体、结构通式为(Ⅲ)的第三单体、结构通式为(IV)的第四单体共聚反应制得的。本发明所述的感光干膜抗蚀剂与现有技术相比,具有显影快、显影后分辨率高、在铜基板上具有较高的附着能力、显影液分散稳定性好且不出现凝聚物、干膜柔韧性优异、盖孔能力和耐电镀液和蚀刻液的能力优异,去膜时间较短的高敏感度的特点。(The invention discloses a high-adhesion plating-resistant photosensitive dry film resist, which comprises 45-65 parts by weight of alkali-soluble copolymer resin, 30-50 parts by weight of photopolymerization monomer, 0.1-4.0 parts by weight of photoinitiator and 0.1-5.0 parts by weight of other additives; the alkali-soluble copolymer resin is prepared by copolymerization reaction of a first monomer with a structural general formula (I), a second monomer with a structural general formula (II), a third monomer with a structural general formula (III) and a fourth monomer with a structural general formula (IV). Compared with the prior art, the photosensitive dry film resist has the characteristics of fast development, high resolution after development, higher adhesion capacity on a copper substrate, good dispersion stability of a developing solution, no generation of condensation, excellent flexibility of a dry film, excellent hole covering capacity, excellent plating solution and etching solution resistance and short film removing time and high sensitivity.)

1.A high-adhesion plating-resistant photosensitive dry film resist is characterized in that: the components comprise 45-65 parts by weight of alkali-soluble copolymer resin, 30-50 parts by weight of photopolymerization monomer, 0.1-4.0 parts by weight of photoinitiator and 0.1-5.0 parts by weight of other additives; the alkali-soluble copolymer resin is prepared by the copolymerization reaction of a first monomer with a structural general formula (I), a second monomer with a structural general formula (II), a third monomer with a structural general formula (III) and a fourth monomer with a structural general formula (IV);

the structural general formula (I) is shown as the following formula,

(Ⅰ)，

wherein R, R is a hydrogen atom or an alkyl group having 1 to C5; n is an integer of 0-6, and the cyclic structure is an alicyclic hydrocarbon group or heterocyclic group; the nitrogen atom of amide bond, urea amine bond or sulfonamide bond connected with the aliphatic ring in the structural formula A, B, C is on the ring or adjacent to the aliphatic ring;

(Ⅱ)，R₄is a hydrogen atom or a methyl group;

(III) wherein R₅Is a hydrogen atom or a methyl group, R₆Selected from alkyl or benzyl of C1-C18;

(IV) wherein R₇Is a hydrogen atom or a methyl group, R₈Is C1-C3 alkyl, C1-C3 alkoxy, amino or halogen atom, and the number of substituents on the benzene ring is 0-5.

2. The high adhesion plating resistant photosensitive dry film resist according to claim 1, wherein: the alkali-soluble copolymer resin has a general formula (I) w (II) x (III) y (IV) z, wherein w, x, y and z respectively represent specific gravities of a first monomer, a second monomer, a third monomer and a fourth monomer, w is 2-50 wt%, x is 15-35 wt%, y is 0-50 wt%, and z is 0-50 wt%.

3. The high adhesion plating resistant photosensitive dry film resist according to claim 1, wherein: the photopolymerization monomer comprises an alicyclic ring modified acrylamide monomer corresponding to the structural formula A of the first monomer, wherein n = 0; the specific gravity of the acrylamide monomer modified by the aliphatic ring in the photopolymerization monomer is 1-10%.

4. The high adhesion plating resistant photosensitive dry film resist according to claim 3, wherein: the aliphatic ring modified acrylamide monomer comprises a compound corresponding to a structural formula shown in the following formula (1);

（1），

wherein R is a hydrogen atom or a methyl group.

5. The high adhesion plating resistant photosensitive dry film resist according to claim 1, wherein: the acid value of the alkali-soluble copolymer resin is 120-250 mg KOH/g resin, the weight average molecular weight is 35000-150000, the molecular weight distribution is 1.3-2.5, and the polymerization conversion rate is more than or equal to 97%.

6. The high adhesion plating resistant photosensitive dry film resist according to claim 1, wherein: the photopolymerisable monomer comprises one or more EO/PO modified bisphenol A structure (methyl) acrylate, the structural formula (2) is shown as the following formula,

（2）；

wherein R represents a hydrogen atom or a methyl group, m1 and m2 are integers of 1 to 30, n1 and n2 are integers of 0 to 20, m1+ m2 are integers of 4 to 30, and n1+ n2 is an integer of 0 to 20; the arrangement mode of the EO and PO repeating units is random or block, EO is ethylene oxide unit, and PO is propylene oxide unit.

7. The high adhesion plating resistant photosensitive dry film resist according to claim 1, wherein: the photopolymerization monomer comprises lauryl methacrylate, octadecyl methacrylate, nonylphenol acrylate, ethoxylated nonylphenol acrylate, propoxylated nonylphenol acrylate, isobornyl ester, tetrahydrofuran methyl acrylate, bisphenol A dimethacrylate, ethoxylated bisphenol A dimethacrylate, propoxylated bisphenol A dimethacrylate and polyethylene glycol propylene glycol dimethacrylate, ethoxylated neopentyl glycol diacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris 2-hydroxyethyl isocyanurate triacrylate, or 4-acryloylmorpholine.

8. The high adhesion plating resistant photosensitive dry film resist according to claim 1, wherein: the photopolymerization monomer is ethoxylated polypropylene glycol (1000) dimethacrylate, and the structural formula (3) is shown as follows:

（3）；

wherein a + c = an integer of 3 to 15, and b = an integer of 12 to 17.

9. The high adhesion plating resistant photosensitive dry film resist according to claim 1, wherein: the photoinitiator is a mixture of acridine derivatives and a hydrogen donor or a mixture of hexaarylbisimidazole derivatives and a sensitizer; the structural formula (4) of the acridine derivative is shown as follows:

（4）；

in the formula, R₉Is alkyl, aryl, substituted aryl, halogenated aryl or pyridyl with 1-6 hydrogen atoms or carbon atoms.

10. The high adhesion plating resistant photosensitive dry film resist according to claim 1, wherein: the other additives comprise one or a plurality of compositions of light color former, coloring agent, plasticizer, antioxidant, deodorant, color-forming heat stabilizer, adhesion promoter, flatting agent, defoaming agent or polymerization inhibitor.

Technical Field

The invention relates to the technical field of printed circuit boards, in particular to a high-adhesion plating-resistant photosensitive dry film resist.

Background

Dry film resists are widely used as key materials for pattern transfer in printed circuit boards, lead frames, solar cells, conductor packages, bga (ball Grid array), cps (chip Size package) packages. In recent years, in order to fabricate a high-precision package substrate, a Laser Direct Imaging (LDI) dry film resist is widely used instead of a conventional dry film resist using an LED or UV light source. Since the position fitting accuracy of the direct laser writing exposure method (LDI) is better, a finer pattern can be obtained.

When a high-resolution dry film resist is produced by the LDI exposure method, the film thickness is required to be reduced to improve the resolution, and the film thickness is generally within 30 μm, and the mechanical strength of the film and the adhesion to the copper substrate are reduced by the reduced film thickness. In order to ensure high resolution and high adhesion, a method of adding benzyl (meth) acrylate, styrene, and styrene derivatives having better adhesion and rigidity as a copolymerization component to an alkali-soluble resin of a photosensitive resin composition, or adding a polyfunctional monomer to a photopolymerizable monomer to increase the crosslinking density is widely used. However, these two methods have disadvantages that the obtained dry film resist becomes hard and brittle, the hole-covering ability becomes poor, the development time and stripping time are greatly increased, the filling property and tracking property of the circuit board having a difference in level are poor, the dispersibility during development is poor, and a large amount of development aggregates (scum) are generated, and if the dry film resist is too brittle, the etching resistance and plating resistance are also degraded, and an etching solution or a plating solution penetrates from the bottom of the dry film resist during the etching or plating step (plating). All these disadvantages cause the bad problems of copper circuit damage, hole breaking, short circuit, etc., and the yield of dry film resist is reduced when it is used by downstream PCB manufacturers, and the production efficiency is also reduced.

In CN 101971097 of Hitachi chemical industry Co., Ltd, an adhesive polymer obtained by copolymerizing conventionally used (meth) acrylic acid, (meth) acrylic acid ester, styrene and derivatives thereof is improved by using an aliphatic ring-modified (meth) acrylic acid ester as a copolymerization component to increase the flexibility of the resulting dry film resist. From the results of examples, the obtained dry film resist had excellent resolution, but had poor adhesion to a copper substrate, a long stripping time, and low photosensitivity.

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide a high-sensitivity photosensitive dry film resist which is fast in development, high in resolution after development, high in adhesion to a copper substrate, good in dispersion stability of a developing solution, free from occurrence of aggregates, excellent in dry film flexibility, excellent in hole-covering ability and resistance to plating solutions and etching solutions, and short in stripping time.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a high-adhesion electroplating-resistant photosensitive dry film comprises 45-65 parts by weight of alkali-soluble copolymer resin, 30-50 parts by weight of photopolymerization monomer, 0.1-4.0 parts by weight of photoinitiator and 0.1-5.0 parts by weight of other additives; the alkali-soluble copolymer resin is prepared by the polymerization reaction of a first monomer with a structural general formula (I), a second monomer with a structural general formula (II), a third monomer with a structural general formula (III) and a fourth monomer with a structural general formula (IV);

the structural general formula (I) is shown as the following formula,

(Ⅰ)，

wherein R, R is a hydrogen atom or an alkyl group having 1 to C5; n is an integer of 0-6, and the cyclic structure is an alicyclic hydrocarbon group or heterocyclic group; the nitrogen atom of amide bond, urea amine bond or sulfonamide bond connected with the aliphatic ring in the structural formula A, B, C is on the ring or adjacent to the aliphatic ring;

(Ⅱ)，R₄is a hydrogen atom or a methyl group;

(III) wherein R₅Is a hydrogen atom or a methyl group, R₆Selected from alkyl or benzyl of C1-C18;

(IV) wherein R₇Is a hydrogen atom or a methyl group, R₈Is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, an amino group or a halogen atom, and the number of substituents on the benzene ring is 0 to 5.

The invention provides a photosensitive dry film resist which has excellent adhesion to metal plates used for PCBs, good flexibility, and good comprehensive properties such as resolution, adhesion, developing rate, stripping speed, plating resistance, development residue, electroplating pollution and the like by introducing a functional monomer into a main chain of an alkali-soluble copolymer resin or using a functional monomer matched with the conventional alkali-soluble copolymer resin as a photopolymerization monomer and applying the photopolymerization monomer to the photosensitive dry film resist.

The weight part of the alkali-soluble copolymer resin is 45-65, and if the weight part is less than 45, the photosensitive layer is easy to overflow; if the weight part is more than 65 parts, the photosensitive resin composition is liable to suffer from problems of low sensitivity and low resolution.

Preferably, the alkali-soluble copolymer resin has the following general formula (I) w (II) x (III) y (IV) z, wherein w, x, y and z respectively represent specific gravities of the first monomer, the second monomer, the third monomer and the fourth monomer, w is 2-50 wt%, x is 15-35 wt%, y is 0-50 wt% and z is 0-50 wt%.

More preferably, the alkali-soluble copolymer resin may be a copolymer resin represented by the general formula (i) w (ii) x (iii) y (iv) z, or a mixed alkali-soluble copolymer resin obtained by compounding 2 or more kinds of copolymer resins having different molecular weights, different acid values, different styrene contents, or the like. Preferably, the acid value of the alkali-soluble copolymer resin is 120-250 mg KOH/g resin, the weight average molecular weight is 35,000-100,000, the molecular weight distribution is 1.3-2.5, and the polymerization conversion rate is more than or equal to 97%. The acid value of the resin is less than 120mg KOH/g, the alkali solubility is poor, the developing and film removing time is prolonged, and poor analysis is caused due to insufficient development; when it exceeds 250mg KOH/g, the development is excessive, resulting in poor resolution. The narrow molecular weight distribution is advantageous for improving the resolution of the photoresist, and when the resolution is more than 2.5, the resolution may be deteriorated.

Preferably, the photopolymerizable monomer comprises an alicyclic modified acrylamide monomer corresponding to the structural formula a of the first monomer and n = 0; the specific gravity of the acrylamide monomer modified by the aliphatic ring in the photopolymerization monomer is 1-10%.

That is, when the corresponding alicyclic modified acrylamide compound with n =0 in the structural formula a, the compound can be polymerized with the second monomer with the general structural formula (ii), the third monomer with the general structural formula (iii), and the fourth monomer with the general structural formula (IV) to obtain the alkali-soluble copolymer resin, so as to further obtain the high-adhesion plating-resistant photosensitive dry film resist. The acrylamide compound modified by the aliphatic ring corresponding to n =0 can be added into the dry film resist as one of the photopolymerization monomers, and the aims of enhancing the flexibility of the high-adhesion plating-resistant photosensitive dry film resist, improving the adhesion between the dry film resist and a copper substrate, improving the plating resistance and the controllability of the dry film resist and adjusting the developing and stripping time can be achieved.

When n =0 in the structure A in the formula (I), the corresponding monomer is a modified acrylamide compound, can be polymerized in a free radical manner in a thermal polymerization manner, and can also be used for photoinitiating a polymer, because the polymer contains an amido bond with larger polarity, the polymer has certain adhesive force to various base materials, and has the characteristics of high reaction speed, strong toughness, better compatibility of toughness and hardness, ultralow odor, good dissolution resistance, good acid and alkali resistance, good stability and the like, thereby being a photocuring dilution monomer with better comprehensive performance. Therefore, when n =0 in the structure a in the formula (i), the corresponding aliphatic ring modified acrylamide monomer can be added to the dry film resist as one of the photopolymerization monomers, and the alkali-soluble resin copolymerized by conventional (meth) acrylic acid, (meth) acrylate or styrene and derivatives thereof is used in combination, so that the aims of enhancing the flexibility of the dry film resist, improving the adhesion with the copper substrate, improving the electroplating and etching resistance, harmonizing the development and reducing the film removal time can be achieved.

Preferably, the aliphatic ring modified acrylamide monomer comprises a compound corresponding to a structural formula shown in the following formula (1);

（1），

wherein R is a hydrogen atom or a methyl group.

Preferably, the photopolymerizable monomer comprises one or more EO/PO modified bisphenol A structure (methyl) acrylate, the structural formula (2) is shown as the following formula,

（2）；

wherein R represents a hydrogen atom or a methyl group, m1 and m2 are integers of 1 to 30, n1 and n2 are integers of 0 to 20, m1+ m2 are integers of 4 to 30, and n1+ n2 is an integer of 0 to 20; the arrangement of the EO and PO repeating units is random or block. EO is an ethylene oxide unit and PO is a propylene oxide unit.

Preferably, the photopolymerizable monomer includes one or more of lauryl (meth) acrylate, stearyl (meth) acrylate, nonylphenol acrylate, ethoxylated nonylphenol acrylate, propoxylated nonylphenol acrylate, isobornyl ester, tetrahydrofuryl acrylate, bisphenol a di (meth) acrylate, ethoxylated bisphenol a di (meth) acrylate, propoxylated bisphenol a di (meth) acrylate, polyethylene glycol (propylene glycol) di (meth) acrylate, ethoxylated (propoxylated) neopentyl glycol diacrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (2-hydroxyethyl) isocyanuric acid triacrylate, or 4-acryloylmorpholine Various compositions are provided.

Preferably, the photopolymerizable monomer is ethoxylated polypropylene glycol (1000) dimethacrylate, and the structural formula (3) is shown as the following formula:

（3）；

wherein a + c = an integer of 3 to 15, and b = an integer of 12 to 17.

Preferably, in order to improve the photosensitivity of the dry film resist to a 405nm wavelength LDI laser light source, the photoinitiator is a mixture of acridine derivatives and a hydrogen donor or a mixture of hexaarylbisimidazole derivatives and a sensitizer; the structural formula of the acridine derivative is shown as a formula (4):

（4）；

wherein R9 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, an aryl group, a substituted aryl group, a halogenated aryl group, or a pyridyl group.

The acridine derivatives comprise 9-phenylacridine, 9-p-phenylacridine, 9-m-tolylacridine, 9-o-tolylacridine, 9-p-chlorophenyl acridine, 1, 7-di (9-acridinyl) heptane and the like.

More preferably, the sensitizer is a pyrazoline sensitizer with tertiary amino as shown in a formula (5);

（5）；

wherein R10, R11 and R12 are alkyl groups of C1-C10 respectively.

Preferably, the other additives include one or more of light color former, coloring agent, plasticizer, antioxidant, deodorant, color-forming heat stabilizer, adhesion promoter, leveling agent, defoaming agent or polymerization inhibitor.

The invention has the following beneficial effects:

1. according to the high-adhesion electroplating-resistant photosensitive dry film resist, amide bonds, urea or sulfonamide bonds with high polarity are introduced into the alkali-soluble copolymer resin, so that the glass transition temperature (Tg) of the resin is increased, the hardness of a film is improved, and the resolution and the mechanical strength of the dry film resist are improved; the introduction of the polar bond also increases the adhesive force between the dry film resist and the copper substrate, increases the compatibility with water, and shortens the developing and film removing time and improves the developing residue and electroplating pollution according to the similar compatibility principle; and a fat ring structure is further introduced, and chemical bonds of the fat ring structure can freely rotate, so that certain flexibility is endowed to the dry film resist. Through the technical scheme adopted by the invention, the dry film resist has sufficient mechanical strength and flexibility.

2. The photopolymerization monomer comprises an acrylic ester monomer modified by ethoxy and propoxy, so that the flexibility of the dry film resist can be enhanced, and the hole covering capability of the dry film resist is improved.

3. The photopolymerisable monomer comprises one or more EO/PO modified bisphenol A structure (methyl) acrylic esters, so that the resolution of the dry film resist is improved.

4. The photoinitiator comprises acridine derivatives and hexaarylbisimidazole derivatives, so that the photosensitivity of the dry film resist to an LDI laser light source with the wavelength of 405nm is improved, the energy required by exposure is reduced, the energy consumption is reduced, and the production efficiency is improved; in addition, the use amount of the photoinitiator is greatly reduced, so that development residues caused by the use of the photoinitiator are reduced.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.

1. The preparation method of the vinyl polymerizable compound

A preparation method of a first monomer corresponding to a structural formula A in a structural general formula (I), namely the vinyl polymerizable compound with amido bond

Adding dichloromethane (500 ml) and cyclohexylamine (1 mol) into a three-neck flask provided with a thermometer, a stirring device, a dropping funnel, a nitrogen protection device and an ice bath cooling device, then adding 1.05-3.0 equivalent of triethylamine, carrying out nitrogen replacement, carrying out ice bath cooling, slowly dropwise adding 1.05-1.5 equivalent of methacryloyl chloride when the temperature of a reaction system is reduced to be lower than 5 ℃, keeping the dropwise adding process for 1 hour, keeping the temperature at 2-5 ℃, continuing to carry out ice bath reaction for 1 hour after the dropwise adding is finished, removing the ice bath, continuing to carry out room temperature reaction for 1 hour, and finishing the reaction. After the reaction is finished, removing hydrochloride of triethylamine generated in the reaction process through vacuum filtration, adding 1M dilute hydrochloric acid (200 ml) into filtrate, stirring for 15 minutes, extracting for 2 times by using dichloromethane (200 ml), washing obtained combined organic phases by using saturated saline solution, drying by using anhydrous sodium sulfate, filtering, concentrating under reduced pressure to obtain a crude product, and dispersing the crude product in petroleum ether: stirring the mixture (300 ml) of ethyl acetate (10: 1) for 1 hour, filtering the mixture under reduced pressure to obtain a solid, and drying the solid to obtain the purified N-cyclohexyl methacrylamide.

B a first monomer corresponding to the general structural formula B in the general structural formula (I), namely the preparation method of the vinyl polymerizable compound with carbamido

Adding 1-amantadine (151 g, 1 mol) and tetrahydrofuran (500 ml) into a three-neck flask provided with a thermometer, a stirring device, a dropping funnel, a nitrogen protection device and an ice bath cooling device, then adding 1.2-1.5 equivalents of triethylamine, replacing with nitrogen, cooling in an ice bath, slowly dropwise adding 0.95-1.0 equivalent of allyl isocyanate when the temperature of a reaction system is reduced to be lower than 5 ℃, keeping the dropwise adding process for 1 hour, keeping the temperature at 2-5 ℃, continuing to perform ice bath reaction for 1 hour after the dropwise adding is finished, removing the ice bath, continuing to perform room temperature reaction for 1 hour, and finishing the reaction. Concentrating under reduced pressure to remove tetrahydrofuran, adding water (500 ml), extracting the water phase with ethyl acetate for 2 times, combining the organic phases, washing with 1M dilute hydrochloric acid and saturated saline solution in sequence, drying with anhydrous sodium sulfate, filtering, concentrating under reduced pressure to obtain a crude product, and dispersing the crude product in petroleum ether: stirring the mixture (300 ml) of ethyl acetate (20: 1) for 1 hour, filtering the mixture under reduced pressure to obtain a solid, and drying the solid to obtain the purified 1-propenyl-3-adamantyl urea.

C A first monomer corresponding to formula C in formula (I), namely said vinyl polymerizable compound having a sulfonamide group

Adding 1-amantadine (151 g, 1 mol) and dichloromethane (500 ml) into a three-neck flask provided with a thermometer, a stirring device, a dropping funnel, a nitrogen protection device and an ice bath cooling device, adding 1.1-2.0 equivalent of triethylamine, replacing with nitrogen, cooling in an ice bath, slowly dropwise adding 0.90-0.95 equivalent of 2-chloroethanesulfonyl chloride when the temperature of a reaction system is reduced to be lower than 5 ℃, removing the ice bath after dropwise adding, and continuously reacting for 5 hours at room temperature. After the reaction, the reaction solution was poured into water (100 ml) to quench, the resulting solution was extracted 3 times with dichloromethane, the combined organic phases were washed with saturated brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to obtain a crude product, which was dispersed in petroleum ether: stirring the mixture (300 ml) of ethyl acetate (10: 1) for 1 hour, filtering the mixture under reduced pressure to obtain a solid, and drying the solid to obtain the purified N-adamantyl vinyl sulfonamide.

2. Synthesis method of alkali-soluble copolymer resin

Uniformly mixing a first monomer, a second monomer, a third monomer and a fourth monomer of an alkali-soluble copolymer monomer according to a certain mass ratio (total 100g), adding 0.3-0.8 g of Azodiisobutyronitrile (AIBN) serving as an initiator, adding 95g of butanone and 15g of ethanol, and stirring for dissolving to obtain a mixed solution. Adding about 35% of the mixed solution in mass fraction into a three-neck flask with a nitrogen protection and condensation reflux device through a peristaltic pump, heating to 78 ℃ through oil bath, stirring for reaction for 1h, slowly dropwise adding the rest mixed solution, and finishing the addition within 3 h. And after continuing the heat preservation reaction for 4 hours, heating to 90 ℃, supplementing 20g of butanone solution dissolved with 0.15-0.3 g of initiator twice at an interval of 1 hour, preserving heat and stirring for 2 hours after finishing the dropwise addition, and finishing the reaction. The alkali-soluble copolymer resin was obtained, and the weight average molecular weight, molecular weight distribution and solid content thereof were measured by Gel Permeation Chromatography (GPC).

The following will describe examples 1 to 10 of the present invention and comparative examples 1 to 4 in detail

According to the proportion of the first monomer, the second monomer, the third monomer and the fourth monomer in the formula of the formula shown in the table 1, alkali-soluble copolymer resin is synthesized, and the mark is A-1-A-11.

TABLE 1 alkali-soluble copolymer resin Components Table

The components are mixed according to the formula shown in the following table 2 in proportion, 60 parts by weight of acetone is added, and then the mixture is fully stirred until the acetone is completely dissolved to prepare a resin composition solution with the solid content of 40%, namely the photosensitive dry film resist.

In Table 2, the photopolymerizable monomer markers B-1 to B-6 represent:

b-1 is (4) ethoxylated bisphenol A di (meth) acrylate having a molecular weight of 512;

b-2 is (10) ethoxylated bisphenol A di (meth) acrylate having a molecular weight of 804;

b-3 is (8) ethoxylated nonylphenol acrylate, molecular weight 626;

b-4 is (3) ethoxylated polypropylene glycol (1000) dimethacrylate, molecular weight 1330;

b-5 is (3) ethoxylated trimethylolpropane triacrylate, molecular weight 428;

b-6 is 4-acryloyl morpholine with the molecular weight of 141.

The photoinitiator marks C-1 to C-3 respectively represent:

c-1 is 2,2 '-bis (2-chlorphenyl) -4, 4' -5,5 '-tetraphenyl-1, 1' -diimidazole in the benzil derivatives;

c-2 is 9-phenylacridine in the acridine derivative;

c-3 is N-phenylglycine.

The additive marks D-1, D-1 to D-3 respectively represent:

d-1 is 1-phenyl-3- (4-dimethylaminostyryl) -5- (4-dimethylamino-phenyl) -pyrazoline (custom synthesis);

d-1 is a brilliant green pigment coloring agent;

d-2 is a leuco crystal violet coupler;

d-3 is a p-methyl benzene sulfonamide plasticizer.

TABLE 2 composition of photosensitive Dry film resist

The photosensitive dry film resists prepared in examples 1 to 10 and comparative examples 1 to 4 were uniformly coated on the surface of a PET support film having a thickness of 15 μm by a coater, and then dried in an oven at 90 ℃ for 10 minutes to form a dry film resist layer having a thickness of 25 μm, which was blue-green under a yellow light. Then, a polyethylene film protective layer having a thickness of 20 μm was laminated on the surface thereof, thereby obtaining a 3-layer photosensitive dry film. The samples were then fabricated into printed circuit samples, which were then evaluated.

The preparation method of the sample comprises film pasting, exposure, development and copper electroplating, and the specific preparation method comprises the following steps:

[ FILM-APPLICATION ]

And polishing the copper surface of the copper-clad plate by a grinder, washing with water, and wiping to obtain a bright and fresh copper surface. The press roll temperature of the laminator is set to be 110 ℃, the conveying speed is 1.5m/min, and the hot lamination is carried out under the standard pressure.

[ Exposure ] to light

Standing the sample for more than 15min after film pasting, exposing by using a Laser Direct Imaging (LDI) exposure machine with the wavelength of 405nm of Shenzhen Kaishun light research, performing photosensitivity test by using a stouffer 41-order exposure ruler, controlling the number of exposure grids to be 14-20 grids, and controlling the exposure energy to be 10-40 mJ/cm²。

[ DEVELOPING ]

The exposed sample is kept stand for more than 15min at the developing temperature of 30 ℃ and the pressure of 1.2Kg/cm²The developing solution is 1 wt% of sodium carbonate aqueous solution, the developing time is 1.5-2.0 times of the minimum developing time, and the developing solution is washed and dried.

[ contamination by electroplating ]

And (3) testing conditions are as follows: 2 Ax 10min at 25 ℃ with stirring.

Copper sulfate: 75 g/L; sulfuric acid: 100 mL/L; chloride ion: 65 ppm; copper additive (copper Gleam PCM Plus): 5 mL/L.

[ DEFILLING ] OF FILM

The film stripping liquid is NaOH with the concentration of 3.0 weight percent, the temperature of 50 ℃ and the pressure of 1.2Kg/cm²The developing solution is 1 wt% sodium carbonate aqueous solution, the developing time is 1.5-2.0 times of the minimum developing time, and the developing solution is washed and dried.

(II) the evaluation method adopted is as follows:

[ evaluation of photosensitivity ]

After the film was applied, the sample was left to stand for 15min or more, exposed using a Kaishikayu 405nm LDI exposure machine, subjected to a sensitivity test using a stouffer 41-stage exposure scale, and after the exposure, sprayed with a 1% wt aqueous solution of sodium carbonate at 30 ℃ for a development time 2.0 times the minimum development time, thereby removing the unexposed portion. After this operation, a cured film formed from a cured product of the photosensitive resin composition was formed on the copper surface of the substrate. The exposure amount (mJ/cm) when the number of remaining stages in the stepwise exposure table obtained as a cured film became 18 stages²) The sensitivity of the photosensitive resin composition was evaluated. The smaller the value, the better the sensitivity.

[ evaluation of resolution ]

The resist pattern was exposed to light using a mask having a wiring pattern with a width of 1:1 of the exposed portion and the unexposed portion, developed at 2 times the minimum development time, and then observed by a two-dimensional imager or a Scanning Electron Microscope (SEM) using the minimum mask width at which the cured resist line was normally formed as a value of resolution.

[ evaluation of adhesion ]

Laminating a photosensitive dry film resist on a copper plate by hot-pressing a pad pasting using a mask having a width n of an exposed portion and an unexposed portion: 400, and then developed with 2 times the minimum development time, the minimum mask width in which the cured resist lines were normally formed was used as the value of adhesion, and the pattern was observed by a two-dimensional imager or a Scanning Electron Microscope (SEM).

[ evaluation of flexibility ]

A dry film resist was laminated on an FPC substrate to obtain a test piece for evaluating flexibility. The sample was left to stand for 15 minutes or more after the film was attached, exposed by a Kaishiki 405nm LDI exposure machine, exposed with a corresponding energy of sensitivity 17/41, and developed with a development time 2 times the minimum development time, to obtain a substrate for evaluation of flexibility in which a dry film resist was laminated on an FPC substrate. Flexibility was evaluated by a mandrel tester, and a substrate for flexibility evaluation was cut into a strip having a width of 2 cm and a length of 10 cm, rubbed with a cylindrical bar at 180 ° for 10 round trips, and then the condition of the dry film resist on the substrate was confirmed, and the diameter of the corresponding round bar where the dry film had no glass or cracks was recorded.

The judgment basis is as follows: the value "O" indicates that 2 mm is not cracked, the value "Delta" indicates that 3 to 4 mm is not cracked, and the value "X" indicates that 5 mm or more is not cracked.

[ evaluation of development residue ]: through the test of a bubble height tester self-made in a laboratory, 18 g of photosensitive dry film resist is weighed and dissolved in 1 wt% of sodium carbonate solution to prepare dry film solution with the mass fraction of 1.8 wt%. During testing, the dry film solution is poured into a spray tank and is circularly sprayed for 1 hour by using a vacuum water pump under the spraying pressure of 0.5 MPa. Then, the developer was left for 7 days, and the resulting developer mixture was filtered through a filter paper under reduced pressure, and then the filter paper was dried. The weight of the filter paper after drying minus the weight of the filter paper before use was recorded as the mass specific gravity of the photosensitive dry film.

The judgment basis is as follows: o (good) -less than 0.5%; delta (general) — 0.5% to 1.0%; 1.0% of x (bad).

[ evaluation of film-Release Rate ]

The film stripping speed is evaluated by testing the film stripping time, and the shorter the film stripping time is, the faster the film stripping speed is.

[ evaluation of plating resistance ]

And (3) at the temperature of 40 ℃, placing the developed substrate in 10% acid degreasing liquid, soaking for 10min, washing for 5min, carrying out sodium persulfate microetching, and soaking for 2 min at room temperature by using 10% sulfuric acid aqueous solution. Then immersing the substrate into a pre-prepared copper plating solution, and electroplating for 70 min at a current density of 2 ASD; soaking in 10% sulfuric acid water solution at room temperature for 2 min, soaking the substrate in tin plating solution with current density of 1ASD, and electroplating for 10 min. And (4) removing the cured dry film after washing, and observing the appearance of the sample by using a 500-time high-resolution scanning electron microscope to determine whether the diffusion coating occurs.

[ evaluation of plating contamination ]

The resist layer sample after exposure (exposure grid number 20) was set at 30dm²The mixture ratio of/L is dissolved in the copper sulfate electroplating solution and is soaked for 7 days at the temperature of 23 ℃. And removing the photosensitive layer by using the soaking solution to obtain the electroplating solution for testing. And comparing the electroplated substrate with the blank sample, and evaluating the difference value of the copper coating thickness of the blank sample and the test sample, wherein the larger the difference value is, the larger the pollution of the electroplating solution is.

The judgment basis is as follows: o (good) -less than 10%; delta (general) — 10% -20%; x (bad) -greater than 20%.

[ evaluation of hole-masking Property ]

The obtained dry film resist was peeled off the protective film, laminated on a porous plate (100 circular holes having a diameter of 6 mm), exposed with exposure energy at a photosite number of 18, developed for 4 times the shortest development time, and counted for the hole breakage rate.

(III) evaluation results

The results of the evaluation of the properties such as sensitivity, resolution, adhesion, flexibility, development residue, film removal rate, plating and plating contamination resistance, and hole-masking ability are shown in Table 3.

Table 3 evaluation results

The comparison of examples 1 to 10 with comparative examples 1 to 4 revealed that: in examples 1 to 10, resin compositions having high sensitivity to LDI exposure light source, good resolution and adhesion properties, good flexibility, good plating resistance, low contamination of plating solution, less development residue, good hole-masking ability, and high film-stripping speed were obtained. In comparative examples 1 to 3, the adhesion was reduced, the film removal time was prolonged, and the plating resistance, the development residue resistance, and the hole masking ability were reduced; in comparative example 4, the alkali-soluble resin modified with a functional monomer was used, and hexaarylbisimidazole was used as an initiator, but no aminopyrazoline was added as a sensitizer, and the obtained dry film resist had low sensitivity and relatively low resolution.

The above-described preferred embodiments of the present invention are not intended to limit the present invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the claims of the present invention.