JP4331178B2 - Resin composition for negative cationic electrodeposition photoresist and electrodeposition coating film formed by coating the same - Google Patents

Description

  The present invention relates to a resin composition for negative cationic electrodeposition photoresist, an electrodeposition liquid formed using the same, and an electrodeposition coating film formed thereby.

Conventionally, anionic and cationic negative-type and positive-type photoresist electrodeposition liquids have been used for etching applications, plating mask applications, and fine processing applications such as printed wiring boards (Patent Documents 1 to 4). reference).
The negative photoresist cures and insolubilizes the deposited coating film by ultraviolet irradiation. Therefore, since the coating film has adhesiveness before ultraviolet irradiation, there is a problem that the resist coating film and the photomask are in close contact with each other when the photomask is bonded. As a method for solving this problem, a method of increasing the glass transition temperature of the resin constituting the photoresist electrodeposition liquid is employed (see Patent Documents 5 and 6). However, in this case, the electrical resistance of the coating film increases during electrodeposition, and the coating film cannot be thickened. Moreover, there existed a problem that the sclerosis | hardenability of a coating film fell at the time of ultraviolet irradiation.
On the other hand, a method of recoating the electrodeposition coating film with non-adhesive polyvinyl alcohol, polyacrylic acid or the like has also been taken (Patent Document 7). However, even in these methods, when a copper-clad laminate with a through hole is used, the inside of the through hole is accumulated, the ultraviolet ray transmission is lowered, and the coating film in the through hole is insufficiently cured. . In addition, there is a problem that a reservoir derived from re-coating can be formed at the edge portion of the substrate, and the resolution does not increase due to poor drying or poor adhesion of the photomask.
Furthermore, when the electrodeposition liquid is circulated for a long period of time, the emulsion breaks down, and the aggregates adhere to the object to be coated or accumulate on the bottom of the tank. There was also a problem with stability.

JP-A-61-080240 Japanese Patent Laid-Open No. 62-262855 Japanese Patent Laid-Open No. 01-191799 JP 04-228598 A JP 2000-256428 A Japanese Patent Application Laid-Open No. 08-339085 JP-A-01-279251

  The present invention has been made for the purpose of solving various problems in the background art as described above. That is, an object of the present invention is to provide an electrodeposition liquid excellent in storage stability and mechanical liquid stability, and a negative-type cationic electrode in which an electrodeposition coating film formed using the electrodeposition film exhibits non-adhesion before exposure. The object is to provide a resin composition for a photoresist.

As a result of intensive studies to solve the above problems, the present inventors have found that a copolymerizable vinyl monomer and a copolymerizable vinyl monomer having a fluoroalkyl group having 1 to 7 carbon atoms in the side chain. A cationic electrodeposition photoresist solution is prepared using a resin composition in which a polyfunctional copolymerizable vinyl monomer and a photopolymerization initiator are blended into a copolymer of As a result, it has been found that the above problems can be overcome, and the present invention has been completed.
As a result of copolymerizing a copolymerizable vinyl monomer having a fluoroalkyl group having 1 to 7 carbon atoms in the side chain, a large number of fluorine atoms are oriented on the surface of the resin particles. In addition, the non-tackiness of the coating is presumed to have been improved.
The resin composition for a negative cationic electrodeposition photoresist of the present invention comprises (A) 18.0 to 93.9 parts by weight of a copolymerizable vinyl monomer and (B) 1 to C carbon atoms in the side chain. A copolymer obtained by copolymerizing 0.1 to 20.0 parts by weight of a copolymerizable vinyl monomer having 7 fluoroalkyl groups, and (C) a polyfunctional copolymerizable vinyl monomer. A negative-type cationic electrodeposition photoresist comprising a total of 100 parts by weight of 5.0 to 50.0 parts by weight of a monomer and 1.0 to 12.0 parts by weight of a photopolymerization initiator (D). Resin composition.

  The electrodeposition liquid using the negative cationic electrodeposition photoresist resin composition of the present invention is excellent in storage stability and mechanical liquid stability, and the electrodeposition coating film formed thereby is also suitable before exposure. In the uncured state, non-adhesiveness is high, and further, there is an effect of showing good plating solution resistance even in the cured state after exposure.

The configuration and operation of the present invention will be specifically described below, but the present invention is not limited thereto. In the present invention, (A) a copolymerizable vinyl monomer, (B) a copolymer obtained by copolymerizing a copolymerizable vinyl monomer having a fluoroalkyl group having 1 to 7 carbon atoms in the side chain. Each component of the coalescence, (C) polyfunctional acrylic monomer, and (D) photopolymerization initiator is an essential component for obtaining a negative electrodeposition photoresist solution.
(A) 18.0 to 93.9 parts by weight of copolymerizable vinyl monomer (a) 3.0 to 16.6 parts by weight of copolymerizable vinyl monomer having an amino group in the side chain (B) The copolymerizable vinyl monomer having no amino group in the side chain is composed of 1.4 to 90.9 parts by weight.

  (A) As a copolymerizable vinyl monomer having an amino group in the side chain constituting a water-soluble or water-dispersible resin in a copolymerizable vinyl monomer, dimethyl (meth) acrylate Examples include aminoethyl, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and acrylamide. (B) As a copolymerizable vinyl monomer having no amino group in the side chain, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, n-hexyl acrylate, n-hexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, heptyl acrylate, heptyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, 2- Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate DOO, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, diethylene glycol acrylate, one or more of diethylene glycol monomethacrylate.

  (B) As a copolymerizable vinyl monomer having a fluoroalkyl group having 1 to 7 carbon atoms in the side chain, 2,2,2-trifluoroethyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2- (perfluoroethyl) ethyl acrylate, 2- (perfluoroethyl) ethyl methacrylate, 1H, 1H, 5H-octafluoropentyl acrylate, 1H, 1H, 5H-octafluoropentyl methacrylate, 2- (perfluorooctyl) ethyl methacrylate, 2- (perfluorooctyl) ethyl acrylate, and the like are listed. F-Tech: product name), biscort F, BISCOAT 3FM (Osaka Organic Chemical Industry Co., Ltd.: trade name), Light Ester M-3F (Kyoeisha Chemical Co., Ltd.: trade name) one or two or more of the like can be used. However, the use of a copolymerizable vinyl monomer having 8 or more fluoroalkyl groups is problematic in terms of industrial use because it is very expensive.

  (C) Polyfunctional acrylic monomers as polyfunctional copolymerizable vinyl monomers include bisphenol F epoxy-modified diacrylate, bisphenol A epoxy-modified diacrylate, isocyanuric acid epoxy-modified diacrylate, polypropylene glycol diacrylate Acrylate, pentaerythritol diacrylate monostearate, polyethylene glycol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolpropane propylene oxide triacrylate, isocyanuric acid epoxy modified triacrylate, trimethylolpropane epoxy modified triacrylate, di Pentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ditrimethylo Propane tetraacrylate, one or more of such pentaerythritol tetraacrylate and the like.

(D) As a photopolymerization initiator, dimethylaminobenzoic acid derived monomer, acetophenone derived monomer, benzophenone derived monomer, benzoin derived monomer, alkylphenone derived monomer, thioxanthone derived monomer, One type or two or more types of sulfonyl azidobenzoic acid, diazodiphenylamine-derived monomer, naphthoquinonediazosulfone-derived monomer, etc. may be mentioned.
(E) As a polymerization initiator for the copolymerizable vinyl monomer, azo compounds such as 2,2′-azobisisobutylnitrile and 2,2′-azobiscyanovaleronitrile, benzoyl peroxide, cumene hydro Examples thereof include peroxide compounds such as peroxide.
(F) Examples of the acid required for neutralization include organic acids such as formic acid, acetic acid, propionic acid, lactic acid, 2-ethylbutanoic acid, and octylic acid, or mineral acids such as sulfuric acid and phosphoric acid.

  (G) As the organic solvent, alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, pentanol, ethylene glycol methyl ether, ethylene glycol ethyl ether, Cellosolves such as ethylene glycol ethyl ether acetate, ethylene glycol-n-butyl ether, ethylene glycol-tert-butyl ether, ethylene glycol-n-hexyl ether, ethylene glycol-2-ethylhexyl ether, ethylene glycol-n-butyl ether acetate, diethylene glycol- n-butyl ether, diethylene glycol-n-hexyl ether, propylene glycol methyl ether, propylene Glycol ether, propylene glycol-n-propyl ether, propylene glycol-n-butyl ether, propylene glycol phenyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol diacetate, dipropylene glycol methyl ether, dipropylene Examples thereof include one or more of glycol ethyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether and the like. In addition, nonionic surfactants that further improve the stability of dyes, pigments and electrodeposition liquids for coloring can also be used.

  In the negative electrodeposition photoresist resin composition of the present invention, the blending ratio of each component is 18.0 to 93.9 parts by weight of the above component (A), (B) 0.1 to 20.0 parts by weight, (C) 5.0 to 50.0 parts by weight and (D) 1.0 to 12.0 parts by weight are required. Further, component (A) is (a) 3.0 to 16.6 parts by weight of a copolymerizable vinyl monomer having an amino group in the side chain, and (b) a copolymerizability having no amino group in the side chain. It contains 1.4 to 90.9 parts by weight of a vinyl monomer. Preferred blending ratios are 47.0-81.0 parts by weight of component (A), 1.0-10.0 parts by weight of (B), 15.0-35.0 parts by weight of (C), (D) 3. It is in the range of 0 to 8.0 parts by weight. At this time, component (A) is (a) 5.0-15.0 parts by weight of a copolymerizable vinyl monomer having an amino group in the side chain, and (b) a copolymer having no amino group in the side chain. 32.0-76.0 parts by weight of the functional vinyl monomer.

On the other hand, when the component (A) is less than 18.0 parts by weight, the water stability of the electrodeposition liquid is lowered, and the liquid stability is also lowered. Moreover, when it exceeds 93.9 weight part, the exposure sensitivity of a coating film will fall. When (a) which constitutes the component (A) is less than 3.0 parts by weight, the water-solubility of the electrodeposition coating film is lowered and the developability is lowered. When it exceeds 16.6 parts by weight, the water resistance of the electrodeposition coating film is lowered and the plating solution resistance is deteriorated. When (b) is less than 1.4 parts by weight, the water resistance of the electrodeposition coating film is lowered and the plating solution resistance is deteriorated. When it exceeds 90.9 parts by weight, the water-solubility of the electrodeposition coating film is lowered and the developability is lowered.
When the component (B) is less than 0.1 parts by weight, the stability of the liquid is lowered and the coating film becomes sticky. Moreover, when it exceeds 20.0 weight part, the plating-solution resistance of a coating film will fall. When the component (C) is less than 5.0 parts by weight, the crosslinking density becomes low and the coating film dissolves during development. Moreover, when it exceeds 50 weight part, the problem that adhesiveness comes out to a coating film arises. When (D) is less than 1.0 part by weight, the exposure sensitivity of the coating film decreases. However, the exposure sensitivity does not improve even if the amount exceeds 12.0 parts by weight.

Moreover, in order to produce the electrodeposition liquid of the present invention, 0.5 to 2.0 parts by weight of component (E) with respect to a total of 100 parts by weight of component (A) and component (B), and organic with respect to amino groups It is necessary to use the acid (F) at a molar ratio of 0.3 to 0.8 and (G) 15.0 to 30.0 parts by weight.
As the electrodeposition conditions of the present invention, in the energization step, the object to be coated is a cathode, the applied voltage is 15 to 250 V, preferably 60 to 160 V, the energization time is 10 to 180 seconds, preferably 10 to 60 seconds, The bath temperature is 25 to 45 ° C, preferably 30 to 40 ° C. The applied voltage may be either a hard start in which a set voltage is applied simultaneously with energization or a soft start in which the voltage is gradually raised to the set voltage.

The electrodeposition-coated object is washed with water, then dried, and after removing moisture and solvent components in the coating film, it is exposed to ultraviolet rays for exposure. As the ultraviolet light source, either a high pressure mercury lamp or a metal halide lamp may be used. Amount for exposure is ^{50mJ / cm 2 ~1000mJ / cm 2} , desirably 200~300mJ / cm ^2.
Exposure is performed through a mask pattern, and a predetermined pattern is baked onto the coating film. In order to increase the resolution of the pattern, the mask pattern is preferably brought into direct contact with the coating film.
The exposed coating film is developed with an organic acid developer, and unexposed portions are dissolved and removed. As this developer, an aqueous solution of an organic acid such as formic acid, acetic acid and lactic acid in an aqueous solution of about 1 to 5% is used in the range of room temperature to 50 ° C., preferably in the range of 35 to 45 ° C. If necessary, the development time can be shortened by adding a nonionic surfactant.

After development, the object to be coated is plated or etched. Then, if an electrodeposition coating film is unnecessary, the coating film is peeled and removed with a stripping solution.
The coating object that can be applied in the present invention is not particularly limited as long as it is not limited to electronic parts for fine processing such as printed circuit boards, lead frames, connector terminals, etc. It can be used as an etching resist. For example, a glass plate on which ITO (Indium Tin Oxide) capable of imparting transparency and conductivity can be deposited may be used.
Further, regarding the use of the electrodeposition liquid of the present invention, other electrodeposition liquids and blends may be used depending on the application.
From the FT-IR measurement, it can be seen that the fluorine atoms preferentially exist on the surface of the electrodeposition coating film prepared in this step. This is shown in FIGS.
In addition, each depth from the coating-film surface of FIGS.

The present invention will be described more specifically with reference to production examples, examples, and comparative examples, but the present invention is not limited to these examples. In addition, the part in a manufacture example, an Example, and a comparative example means a weight part unless there is particular notice.
(Production Example 1)
Production of a water-soluble or water-dispersible vinyl copolymer 30 parts by weight of isopropyl alcohol is charged in a 3 liter four-necked flask equipped with a stirrer, a reflux device and a nitrogen introduction tube, and the temperature is raised to 80 ° C. did. Separately, 10 parts of isopropyl alcohol, 10 parts of dimethylaminoethyl methacrylate, 5 parts of 2-ethylhexyl acrylate, 5 parts of 2-ethylhexyl methacrylate, 5 parts of ethyl acrylate, 18 parts of butyl acrylate, 52 parts of methyl methacrylate, 2,2,2-trifluoro A mixed solution of 5 parts of ethyl acrylate and 1 part of azobisisobutyronitrile was charged into a dropping funnel and dropped into the flask over 120 minutes.
After completion of the dropwise addition, 3 parts of isopropyl alcohol and 0.5 part of azobisisobutyronitrile were added three times every 30 minutes, and the reaction was continued at 90 ° C. for 180 minutes. After completion of the reaction, 25 parts of dipentaerythritol penta and hexaacrylate (manufactured by Toagosei Co., Ltd., multifunctional copolymerizable vinyl monomer, Aronix M-400: trade name), 2-methyl-1 [4- (Methylthio) phenyl] -2-monoforinopropan-1-one (manufactured by Ciba-Geigy Co., Ltd., photopolymerization initiator, Irgacure 907: trade name), 5 parts, 2,4-diethylthioxanthone (Nippon Kayaku ( Co., Ltd. product, photopolymerization initiator, Kayacure DETX-S (trade name) 2 parts was added to obtain an acrylic polymer.

(Production Examples 2 to 11)
Regarding Production Examples 2 to 11, the blending ratio of Production Example 1 to methyl methacrylate, a monomer having an amino group in the side chain, a fluorine monomer, a polyfunctional copolymerized vinyl monomer, and a photopolymerization initiator is different. Except for this, each electrodeposition resin was prepared by the same method. The formulation is shown in Table 1.
[Example 1]
After adding 16 parts of propylene glycol monomethyl ether and 3.0 parts of 80% lactic acid to 183.5 parts of the acrylic copolymer of Production Example 1 and sufficiently stirring, 1117.5 parts of deionized water is added and the heating residue 10 % Electrodeposition solution was prepared.
[Examples 2 to 7]
For each of Production Examples 2, 4, 5, 7, 9, and 11, the copolymer used in Example 1 is Production Example 2 in Example 2, Production Example 5 in Example 3, Production Example 6 in Example 4, and Production Example 6 Each electrodeposition solution was prepared in the same manner as in Example 1 except that Example 5 was Manufacturing Example 7, Example 6 was Manufacturing Example 9 and Example 7 was Manufacturing Example 11.

[Comparative Examples 1-4]
As for Comparative Examples 1 to 4, the acrylic copolymer used in Example 1 is Comparative Example 1, Production Example 3, Comparative Example 2 is Production Example 4, Comparative Example 3 is Production Example 8, and Comparative Example 4 is Production Example 10. Except for this point, each electrodeposition solution was prepared by the same method. Table 2 shows the electrodeposition liquid mixture ratios and evaluations of Examples 1 to 4 and Comparative Examples 1 and 2, and the evaluation of the coating film.
[Method for evaluating resin composition]
Using the electrodeposition solutions prepared in Examples 1 to 7 and Comparative Examples 1 to 4, using a copper plate having a thickness of 0.2 mm for the cathode and an 18-8 stainless steel plate for the anode according to a conventional method, a bath temperature of 35 ° C. A DC voltage was applied between both electrodes for 60 seconds. Next, the electrodeposited copper plate was taken out and washed thoroughly with water, and then dried at a temperature of 60 ° C. for 120 seconds. The applied voltage can be arbitrarily changed between 80 V and 180 V in order to obtain a coating thickness of 10 μm. The curing condition of the coating film deposited under the above conditions was 300 mJ / cm ² .

The compositions, physical property tests and evaluation methods in Table 2 are as follows.
(1) *: 10% solid content
(2) Storage stability: The electrodeposition solution was allowed to stand at room temperature for 5 months, and the presence or absence of sediment was determined. If sediment was generated, it was judged as bad.
(3) Mechanical liquid stability: The stability of the electrodeposition liquid under a shearing force with a spiral pump was measured. With a centrifugal pump (MD-30, manufactured by Iwaki Co., Ltd.), 3 liters of electrodeposition solution is continuously circulated at 45 ° C. for 8 hours at a circulation rate of 10 liters / minute. After the test, the solution was used for electrodeposition on a copper plate of 50 × 100 (mm), and if there was an aggregate having a diameter of 50 to 200 μm in the electrodeposition coating film as observed with a stereomicroscope, it was judged as good if it was not.
(4) Non-adhesiveness of the coating film before exposure: Evaluated by the adhesion between the electrodeposition coating film after drying and the polyethylene film. A film thickness of 10 ± 1 μm was applied to a copper plate of 50 × 100 (mm) by the above electrodeposition method, and a polyethylene film was bonded to the electrodeposition coating film and adhered at 40 ° C. under a load of 20 g / cm ² for 3 minutes. The peel load was measured at an angle of 180 °. When the average value of the peel strength was 20 mN / cm or more, it was poor and less than good.
(5) Resistance to plating solution: After electrodeposition on a copper plate and drying at a temperature of 60 ° C. for 120 seconds, the intensity of light at a wavelength of 365 nm is 200 mW / mm with a metal halide lamp through a photomask having a predetermined pattern. The electrodeposition coating film was exposed for 2 seconds with ultraviolet rays of cm ² and immersed in an aqueous solution having a temperature of 40 ° C. and a lactic acid concentration of 1% by weight for 2 minutes to develop the electrodeposition coating film in the unexposed portion. Then, plating on the object to be coated with a silver cyanide plating solution (Serenabright N-50 manufactured by Nippon Kogyo Kagaku Co., Ltd.) is performed by applying a rectangular wave of 60 Hz for 1 minute at a voltage of −3 V to perform plating. The penetration was measured. If the silver plating soaked and deposited at the interface between the copper plate of the substrate and the developed electrodeposition coating film, it was judged as bad.

  The electrodeposition liquid using the negative cationic electrodeposition photoresist resin composition of the present invention is excellent in storage stability and mechanical liquid stability, and the electrodeposition coating film formed thereby is also suitable before exposure. In the uncured state, non-adhesiveness is high, and even in the cured state after exposure, it exhibits good plating solution resistance, and is extremely useful industrially in the technical field of negative-type cationic electrodeposition photoresists.

It is a FT-IR chart figure of the coating-film surface (depth 0 micrometer). It is a FT-IR chart figure of depth 4micrometer. It is a FT-IR chart figure of depth 12 micrometers. It is a FT-IR chart figure of a depth of 16 micrometers. Relationship between depth from coating film surface (D, μm) and absorbance ratio (C).

Explanation of symbols

A: The peak at 1280 cm ⁻¹ mainly shows absorption of C—F bonds. That is, the fluorine content in all (meth) acrylic resins is shown.
B: The peak at 1730 cm ⁻¹ mainly indicates carbonyl absorption. That is, the total (meth) acrylic resin content is shown.
C: Absorbance ratio of A to B. That is, the ratio of the fluorine content to the total (meth) acrylic resin content is shown.
D: Depth (μm) from the coating film surface.

Claims (3)

  The resin component constituting the negative cationic photoresist electrodeposition liquid is (A) 18.0 to 93.9 parts by weight of a copolymerizable vinyl monomer, and (B) A copolymer obtained by copolymerizing 0.1 to 20.0 parts by weight of a copolymerizable vinyl monomer having 7 fluoroalkyl groups, and (C) a polyfunctional copolymerizable vinyl monomer. A negative cation characterized in that it is a resin composition comprising a total of 100 parts by weight of 5.0 to 50.0 parts by weight of a monomer and (D) 1.0 to 12.0 parts by weight of a photopolymerization initiator. Resin composition for conductive electrodeposition photoresist.   (A) 18.0 to 93.9 parts by weight of the copolymerizable vinyl monomer (a) 3.0 to 16.6% by weight of (a) a copolymerizable vinyl monomer having an amino group in the side chain The negative-type cationic electrodeposition according to claim 1, characterized in that 1.4 to 90.9 parts by weight of (b) a copolymerizable vinyl monomer having no amino group in the side chain. Resin composition for photoresist.   An electrodeposition coating film formed by an electrodeposition liquid using the resin composition for negative cationic electrodeposition photoresists according to claim 1 or 2.

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