Photosensitive resin composition and dry film resist
阅读说明：本技术 感光性树脂组合物、干膜抗蚀剂 (Photosensitive resin composition and dry film resist ) 是由 朱高华 于 2019-09-14 设计创作，主要内容包括：本发明公开了一种感光性树脂组合物、干膜抗蚀剂。该树脂组合物包括40～70重量份的碱可溶性树脂、20～50重量份的光聚合单体、0.5～10.0重量份光引发剂和0.1～10.0重量份添加剂,所述碱可溶性树脂含有15～35质量％的来自(甲基)丙烯酸的结构单元、通式15～55质量％的来自(甲基)丙烯酸苄基酯的结构单元、和15～55质量％的苯乙烯的结构单元。本发明的感光性树脂组合物用作干膜抗蚀剂时避免了侧蚀和渗镀的现象,得到的干膜抗蚀剂具有优异的附着力、分辨率和柔韧性。(The invention discloses a photosensitive resin composition and a dry film resist. The resin composition comprises 40-70 parts by weight of an alkali-soluble resin, 20-50 parts by weight of a photopolymerizable monomer, 0.5-10.0 parts by weight of a photoinitiator, and 0.1-10.0 parts by weight of an additive, wherein the alkali-soluble resin contains 15-35% by mass of a structural unit derived from (meth) acrylic acid, 15-55% by mass of a structural unit derived from benzyl (meth) acrylate of a general formula, and 15-55% by mass of a structural unit derived from styrene. When the photosensitive resin composition is used as a dry film resist, the phenomena of side etching and diffusion plating are avoided, and the obtained dry film resist has excellent adhesion, resolution and flexibility.)
1. A photosensitive resin composition comprising 40 to 70 parts by weight of an alkali-soluble resin, 20 to 50 parts by weight of a photopolymerizable monomer, 0.5 to 10.0 parts by weight of a photoinitiator, and 0.1 to 10.0 parts by weight of an additive, wherein the alkali-soluble resin contains 15 to 35% by mass of a structural unit derived from (meth) acrylic acid of the general formula (1), 15 to 55% by mass of a structural unit derived from benzyl (meth) acrylate of the general formula (2), and 15 to 55% by mass of a structural unit derived from styrene of the general formula (3);
general formula (1)
General formula (3)
Wherein, in the general formulas (1), (2) and (3), R1 and R2 are respectively and independently selected from hydrogen atoms or methyl.
2. The photosensitive resin composition according to claim 1, wherein the alkali-soluble resin has a weight average molecular weight of 10000 to 150000 and a resin acid value of 100 to 230mg KOH/g.
3. The photosensitive resin composition according to claim 2, wherein the weight average molecular weight of the alkali-soluble resin is 20000 to 120000, and the acid value of the resin is 120 to 180mg KOH/g.
4. The photosensitive resin composition according to claim 1, wherein the alkali-soluble resin has a molecular weight distribution index (Mw/Mn) of 1.0 to 3.0.
5. The photosensitive resin composition according to claim 4, wherein the alkali-soluble resin has a molecular weight distribution index (Mw/Mn) of 1.0 to 2.0.
6. The photosensitive resin composition according to claim 1, the photopolymerizable monomer is selected from one or more of lauryl (meth) acrylate, stearyl (meth) acrylate, nonylphenol acrylate, ethoxylated (propoxylated) nonylphenol acrylate, isobornyl acrylate, tetrahydrofuryl acrylate, bisphenol a di (meth) acrylate, ethoxylated (propoxylated) bisphenol a di (meth) acrylate, polyethylene glycol (propylene glycol) di (meth) acrylate, ethoxylated (propoxylated) neopentyl glycol diacrylate, trimethylolpropane tri (meth) acrylate, ethoxylated (propoxylated) trimethylolpropane tri (meth) acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.
7. The photosensitive resin composition according to claim 6, wherein the photopolymerizable monomer is ethoxylated bisphenol A di (meth) acrylate or ethoxylated trimethylolpropane tri (meth) acrylate.
8. The photosensitive resin composition according to claim 1, wherein the photoinitiator is selected from the group consisting of 2,4, 5-triarylimidazole dimer and derivatives thereof, acridine derivatives such as N, N ' -tetramethyl-4, 4' -diaminobenzophenone, N ' -tetraethyl-4, 4' -diaminobenzophenone, 9-phenylacridine, 1, 7-bis (9,9' -acridinyl) heptane and the like, N-phenylglycine, coumarin-based compounds, oxazole-based compounds; the 2,4, 5-triaryl imidazole dimer and derivatives thereof comprise one or more of 2- (o-chlorophenyl) -4, 5-diphenyl imidazole dimer, 2- (o-chlorophenyl) -4, 5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4, 5-diphenyl imidazole dimer, 2- (o-methoxyphenyl) -4, 5-diphenyl imidazole dimer and 2- (p-methoxyphenyl) -4, 5-diphenyl imidazole dimer.
9. The photosensitive resin composition according to claim 1, wherein the additive is one or more selected from the group consisting of a plasticizer, a defoaming agent, and a polymerization inhibitor.
10. A dry film resist comprising the photosensitive resin composition according to any one of claims 1 to 9.
Technical Field
The invention belongs to the technical field of printed circuit boards, and particularly relates to a photosensitive resin composition and a dry film resist.
Background
In the field of printed wiring board production, photosensitive resin compositions are widely used as resist materials for etching or plating. A conventional printed wiring board is manufactured by using a photosensitive resin composition and by the method shown below: first, a photosensitive resin composition is coated on a substrate (a stamper); then, ultraviolet irradiation is performed on a portion of the photosensitive resin composition layer to cure (expose) the exposed portion. After the support film PET was peeled off after a certain period of time, the unexposed portion was removed from the substrate with a medicinal solution (developed), thereby forming a photosensitive resist pattern on the substrate. After a circuit is formed on a substrate on which a resist pattern is formed by performing etching or plating, the resist is finally removed (film removal).
Miniaturization and multi-functionalization of electronic products require finer line spacing and higher density of printed wiring boards. This places more stringent requirements on the properties of the photosensitive resist material used to form fine lines. The adhesion between the photosensitive resist layer and the copper substrate is poor, and the resist pattern can float from the substrate and be corroded by etching liquid medicine or electroplating liquid medicine to cause fine line open circuit; when the resist layer is developed, the water remaining between the resist patterns causes the resist components to be eluted between the patterns to cause short circuits, and it is necessary to increase the hydrophobicity of the photosensitive resist layer in order to reduce the water remaining between the resist lines; the photoresist layer with poor flexibility can also cause copper surface corrosion and gap open circuit due to the insufficient filling of copper wire grooves to be protected.
The hydrophobicity of the photosensitive resist layer can be improved by adding a hydrophobic compound to the resist resin. Patent document CN 101971097a has improved the hydrophobicity of the resist layer by using an alkali-soluble resin of (meth) acrylate and derivatives thereof and styrene and derivatives thereof having a specific structure, thereby producing a dry film resist having good resolution and adhesion. The alkali-soluble resin is obtained by using (meth) acrylate having a specific structure and a derivative thereof, for example, (meth) acrylate having an alicyclic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or a heterocyclic group which may have a substituent. However, the (meth) acrylate having a specific structure as described above has a large steric hindrance during polymerization due to the direct linkage of the acyloxy group to the ring structure, and the conversion is not complete, and the resulting alkali-soluble resin has a high glass transition temperature, which may cause a decrease in flexibility of the resist, causing undercut and plating.
Disclosure of Invention
The invention aims to make up the defects of the prior art and provides a photosensitive resin composition, wherein a carbon atom is connected between an acyloxy group and a benzene ring in benzyl (meth) acrylate, so that the photosensitive resin composition has better flexibility and smaller steric hindrance than a structural unit directly connected with the benzene ring or a heterocyclic ring, can fully react during polymerization, and can obtain an alkali-soluble resin with better flexibility and low monomer residue rate.
In order to achieve the purpose, the invention adopts the following technical scheme:
a photosensitive resin composition comprising 40 to 70 parts by weight of an alkali-soluble resin, 20 to 50 parts by weight of a photopolymerizable monomer, 0.5 to 10.0 parts by weight of a photoinitiator, and 0.1 to 10.0 parts by weight of an additive, wherein the alkali-soluble resin contains 15 to 35% by mass of a structural unit derived from (meth) acrylic acid of the general formula (1), 15 to 55% by mass of a structural unit derived from benzyl (meth) acrylate of the general formula (2), and 15 to 55% by mass of a structural unit derived from styrene of the general formula (3);
general formula (1)
General formula (3)
Wherein, in the general formulas (1), (2) and (3), R1 and R2 are respectively and independently selected from hydrogen atoms or methyl.
Further, the weight average molecular weight of the alkali soluble resin is 10000-150000, and the acid value of the resin is 100-230 mg KOH/g; more preferably, the weight average molecular weight of the alkali-soluble resin is 20000-120000, and the acid value of the resin is 120-180 mg KOH/g.
Further, the alkali-soluble resin has a molecular weight distribution index (Mw/Mn) of 1.0 to 3.0, preferably 1.0 to 2.0.
The alkali soluble resin, preferably 40-70 weight portions, when the weight portion is less than 40, the photosensitive resin composition is easy to overflow glue and is not easy to store; when the weight part is more than 70 parts, there is a risk of low sensitivity and poor resolution. When the weight average molecular weight of the resin is less than 10000, the developing solution resistance tends to decrease; when it exceeds 150000, the developing and film-removing time tends to be long. When the molecular weight distribution index of the resin exceeds 3.0, there is a risk of deterioration in adhesion and resolution.
Further, the photopolymerizable monomer is selected from one or more of lauryl (meth) acrylate, stearyl (meth) acrylate, nonylphenol acrylate, ethoxylated (propoxylated) nonylphenol acrylate, isobornyl ester, tetrahydrofuryl acrylate, bisphenol a di (meth) acrylate, ethoxylated (propoxylated) bisphenol a di (meth) acrylate, polyethylene glycol (propylene glycol) di (meth) acrylate, ethoxylated (propoxylated) neopentyl glycol diacrylate, trimethylolpropane tri (meth) acrylate, ethoxylated (propoxylated) trimethylolpropane tri (meth) acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate. The photopolymerizable monomer is preferably ethoxylated bisphenol a di (meth) acrylate or ethoxylated trimethylolpropane tri (meth) acrylate.
The above-mentioned photopolymerizable monomer is preferably 20 to 50 parts by weight, and if the amount is less than 20 parts by weight, the photosensitive resin composition tends to have problems of low sensitivity and low resolution; if the amount is more than 50 parts by weight, the photosensitive layer may bleed, resulting in a short shelf life.
Further, the photoinitiator is selected from 2,4, 5-triarylimidazole dimer and derivatives thereof, acridine derivatives such as N, N ' -tetramethyl-4, 4' -diaminobenzophenone, N ' -tetraethyl-4, 4' -diaminobenzophenone, 9-phenylacridine, 1, 7-bis (9,9' -acridinyl) heptane, N-phenylglycine, coumarin compounds, and oxazole compounds; the 2,4, 5-triaryl imidazole dimer and derivatives thereof comprise one or more of 2- (o-chlorophenyl) -4, 5-diphenyl imidazole dimer, 2- (o-chlorophenyl) -4, 5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4, 5-diphenyl imidazole dimer, 2- (o-methoxyphenyl) -4, 5-diphenyl imidazole dimer and 2- (p-methoxyphenyl) -4, 5-diphenyl imidazole dimer.
Further, the additive is selected from one or more of a plasticizer, a defoaming agent and a polymerization inhibitor.
The invention also provides a dry film resist, which comprises the photosensitive resin composition.
The invention has the following technical characteristics:
(1) the alkali soluble resin in the photosensitive resin composition has higher flexibility and low monomer residue rate;
(2) when the photosensitive resin composition is used as a dry film resist, the phenomena of side etching and diffusion plating are avoided, and the obtained dry film resist has excellent adhesion, resolution and flexibility.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.
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.
In the present invention, (meth) acrylic acid means acrylic acid and methacrylic acid, and benzyl (meth) acrylate means benzyl acrylate and benzyl methacrylate.
First, examples 1-6 and comparative examples 1-2 specific components and weight ratios thereof (see Table 2)
(1) Alkali-soluble resin a: prepared by solution polymerization, the solvent is butanone, and the comonomer is shown in Table 1.
TABLE 1 comonomer, acid value, molecular weight of alkali-soluble resins A-1 to A-7
(2) Photopolymerizable monomer B:
b-1: (8) ethoxylated nonylphenol acrylate, molecular weight 626 (sartomer);
b-2: (9) ethoxylated dimethacrylate, molecular weight 598 (meiyuan);
b-3: (3) ethoxylated trimethylolpropane triacrylate, molecular weight 428 (sartomer);
(3) a photoinitiator C:
c-1: 2,2 ', 4-tris (2-chlorophenyl) -5- (3, 4-dimethoxyphenyl) -4', 5 '-diphenyl-1, 1' -diimidazole (a new powerful electron material in Changzhou);
c-2: n-phenylglycine (Western Asia chemical).
(4) And (3) an additive D:
d-1: brilliant green pigment (Shanghai Bailingwei chemical technology Co., Ltd.);
d-2: leuco crystal violet (Shanghai Bailingwei chemical technologies, Inc.);
d-3: tribromomethyl phenyl sulfone (Shanghai ladder love chemical industry);
d-4: n, N-diethylhydroxylamine (Shanghai Bailingwei chemical technology Co., Ltd.).
TABLE 2 weight ratios of the components of examples 1-6 and comparative examples 1-2
Second, preparation of photosensitive Dry films of examples and comparative examples
The preparation method comprises the following specific steps:
(1) mixing the components according to the proportion of the photosensitive resin composition in the table 2, adding acetone, and fully stirring until the acetone is completely dissolved to obtain a resin composition solution with the solid content of 40%;
(2) uniformly coating the resin composition solution on the surface of a PET (polyethylene terephthalate) support film with the thickness of 15 mu m by using a coating machine, and drying in a drying oven at 90 ℃ for 10min to form a dry film resist layer with the thickness of 25 mu m, wherein the dry film resist layer presents blue-green under a yellow light;
(3) and (3) attaching a polyethylene film protective layer with the thickness of 20 mu m to the surface of the dry film resist layer to obtain the photosensitive dry film with the 3-layer structure.
Third, sample preparation methods (including film pasting, exposure, development, etching, film removal), sample evaluation methods, and evaluation results of examples and comparative examples.
(1) Sample preparation method
[ 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 16-22 grids, and controlling the exposure energy to be 16mJ/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% 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.
[ 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 film removing time is 1.5-2.0 times of the minimum film removing time, and the film is washed and dried after being removed.
(2) Evaluation method
[ evaluation of plating resistance ]
After exposure using a mask having a wiring pattern with a width of 1:1 of the exposed portion and the unexposed portion, development was performed for 1.5 times of the minimum development time, the evaluation sample was subjected to acid degreasing, water washing, sulfuric acid immersion, and copper plating treatment using a copper sulfate plating solution under a condition of 1A/dm2 for 10 min. Then washing and stripping the film, and measuring the diffusion plating width of the plating layer by using an optical microscope. The smaller the value of the plating width, the better the plating resistance.
The judgment grade is good: 0 um; in general: 1-2 um; difference: more than 3 um.
[ evaluation of resolution ]
After exposure using a mask having a wiring pattern with a width of 1:1 of the exposed portion and the unexposed portion and development with 1.5 times of the minimum development time, the minimum mask width where the cured resist line was normally formed was observed with a magnifying glass as a value of resolution.
[ evaluation of adhesion ]
A photosensitive dry film resist was laminated on a copper plate by hot-pressing a film, exposed to light using a mask having a wiring pattern with a width of n:400 of an exposed portion and an unexposed portion, developed for 1.5 times of the minimum development time, and then observed with a magnifying glass using the minimum mask width where a cured resist line was normally formed as a value of adhesion.
[ evaluation of flexibility ]
After film pasting, exposure and development, folding the flexible base material for 20 times from different angles, observing whether the dry film cracks, counting the cracking times, and expressing the result by using a number, wherein the smaller the numerical value, the better the flexibility of the dry film is.
Well: the dry film is cracked for 0-1 time after being folded; in general: the dry film is cracked for 2-5 times after being folded; difference: the dry film is cracked for more than 5 times after being folded in half.
The evaluation results of the plating resistance, resolution, adhesion and flexibility are shown in Table 3
TABLE 3 evaluation results of examples 1 to 6 and comparative examples 1 to 2
By comparing examples 1-6 with comparative examples 1-2, it can be found that: examples 1 to 6 all obtained resin compositions having stable resolution, adhesion property, and excellent flexibility and plating resistance. In comparative example 1, although the adhesion and the resolution were good, the flexibility and the plating resistance were poor; in comparative example 2, the plating resistance was general, but the resolution and flexibility were poor.
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core ideas. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.