JPH05121863A - Manufacture of printed wiring board - Google Patents

Abstract

PURPOSE:To form a solder resist pattern of high accuracy by forming a solder resist film and thereafter by forming a solder resist pattern thereon. CONSTITUTION:A first solder resist ink composition is applied by screen print all over a printed wiring board wherein a conductor circuit is formed, it is dried, an alkali soluble first solder resist coat is formed and it is dried at 80 deg.C for 20 minutes. Then, ultraviolet-curing solder resist is screen-printed to a thickness of 15 to 20mum as second solder resist ink on a solder resist film. Thereafter, a coat is cured at a light amount of 1000mj/cm<2> using an radiation device which is used for screen print. After cured, it is developed for 30 seconds by 1% sodium carbonate water solution and thermally cured for 30 minutes at 150 deg.C to acquire a solder resist pattern. Thereby, a solder resist pattern of high precision can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board, which comprises forming a solder resist film on a printed wiring board and a solder resist pattern on the solder resist film.

[0002]

2. Description of the Related Art Electronic components mounted on a printed wiring board are usually fixed by soldering. At that time, in order to prevent a conductor circuit or the like from being short-circuited by soldering, a portion other than a portion required for soldering is covered with a solder resist. As a method for forming this solder resist, methods such as a silk screen printing method, a dry film photo solder resist method, and a liquid photo solder resist method are well known and widely used. Among them, the silk screen printing method is widely used because of its high processing capacity and its simple and easy operation.

However, recently, with the surface mounting of printed wiring boards, a highly accurate solder resist pattern has been required. Therefore, the silk screen printing method conventionally used cannot meet this requirement. Not only that, but new problems arose. That is, when printing the solder resist ink on the printed wiring board,
The thickness of the copper circuit is 35 μm to 100 μm and is not smooth surface printing, the printed surface is made of two kinds of materials having different properties of the laminated plate base material and copper, and further,
Factors such as narrow pattern intervals are a bottleneck,
When printing, change the screen mesh,
Not only is it necessary to perform complicated operations such as adjusting the ink application amount, but even if such operations are performed, solder resist bleeds on the soldered parts and connection parts, and non-soldered copper circuit parts Problems such as skipping were unavoidable.

Therefore, in order to solve these problems, the double-printing method and the scooping method are partially adopted, but the essential solution has not been reached. In the case of photographic methods such as liquid photo solder resist and dry film photo solder resist, 1/3 of screen printing method
It is not always a satisfactory method because it can only obtain a processing capacity of about 1/4. Therefore, it is possible to make use of the screen printing technology and the production process, which are easy to handle and easy to handle, and have excellent processing ability, and to prevent bleeding, skipping, etc., like the photographic methods such as liquid photo solder resist and dry film photo solder resist. It has been strongly desired to develop a manufacturing method of a printed wiring board for forming a solder resist pattern with high accuracy that does not occur.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation. That is, an object of the present invention is to provide a method for producing a printed wiring board for forming a solder resist pattern which shows higher accuracy than the conventional screen printing method without causing bleeding, skipping, etc. and has excellent processing ability. The purpose is to do.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that in forming a solder resist pattern, first, a solder resist film is formed and then a solder resist pattern is formed thereon. The inventors have found that the above object can be achieved and completed the present invention. That is, the method for manufacturing a printed wiring board according to the present invention includes (1) applying the first solder resist ink on the entire surface of the printed circuit board on which the conductor circuit is formed, temporarily drying the ink with heat, and then using an alkaline aqueous solution or an organic solvent. A step of forming a soluble solder resist film, (2) a step of pattern printing with a second solder resist ink on the formed solder resist film, and a step of curing with ultraviolet rays, (3) development with an alkaline aqueous solution or an organic solvent A printed wiring board having a solder resist pattern formed on a conductor circuit, which is characterized by comprising: a step of performing a treatment; and (4) a step of heating and post-curing the formed solder resist pattern. ..

The present invention will be described in detail below. FIG. 1 is an explanatory view showing a pattern forming step of forming a solder resist pattern of the present invention. In FIG.
(A) shows the board | substrate with which the conductor circuit was formed, (b)
Shows the state where the solder resist film was formed in the first step, (c) shows the state where the solder resist pattern was formed in the second step, and (d) was developed in the third step. Indicates the state.

The method of the present invention will be described with reference to FIG. 1. In the first step, the first solder resist ink is applied to the entire surface of the printed circuit board 1 on which a predetermined conductor circuit 2 is formed, and is temporarily dried by heat. To do. As a result, the solder resist film 3 soluble in the alkaline aqueous solution or the solvent is formed on the entire surface. (See FIGS. 1A and 1B.) The coating operation in this first step may be performed once, or may be repeated a plurality of times by repeating coating and drying. The application may be performed by any method, for example,
A screen printing method, an offset printing method, a spray coating method, a curtain coating method and the like can be used. In addition, temporary drying is
It can be performed by heating, but it is necessary that the formed solder resist film is kept dry to the touch. The thickness of the solder resist film is usually 5 to 40
It is preferable to set in the range of 5 μm, particularly 5 to 20 μm.

In the second step, a predetermined pattern is printed on the solder resist film 3 using the second solder resist ink to cure the formed solder resist pattern 4 (see FIG. 1 (c). )reference).
The pattern printing is performed by a screen printing method. Further, this curing can be performed by irradiating with ultraviolet rays, but it is necessary to perform the curing to such an extent that the solubility of the solder resist film 3 in the alkaline aqueous solution or the solvent is maintained. A low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, or the like can be used as the irradiation light source of ultraviolet rays. The film thickness of the resist pattern formed by pattern printing is usually 10 to 30 μm, and preferably 15 to 25 μm.

Next, in the third step, the film formed using the first and second solder resist inks as described above is developed. The development process is performed with an alkaline aqueous solution or an organic solvent, whereby the portion where the solder resist pattern 4 is not formed is removed (see FIG. 1D).

Finally, in the fourth step, the first and second steps are performed.
The pattern-shaped solder resist film formed with the solder resist ink of (1) is post-cured by heating. The heating means is not particularly limited, and known one can be used.

Next, the materials used in the above steps will be described. The first solder resist ink used in the first step has an alkali or solvent-soluble resin as a main component, and the film formed is cured by heat. Any resin component can be used as long as it exhibits at least one of the properties of dissolution, swelling, and peeling and is cured by heat. For example, novolac resin, rosin resin, rosin-modified resin, and carboxyl-containing resin can be used. Examples include coalescing. These resins may simultaneously be solvent soluble.

The rosin-modified resin is a resin represented by a rosin-modified maleic acid resin, and a rosin modified by reacting an acid or an alcohol can be usually used. Specifically, Harimack R-80, Harimack 145P
(These are manufactured by Harima Kasei Chemical Co., Ltd.).

The carboxyl group-containing polymer is a polymer containing a carboxyl group in the polymer chain. Homopolymers of monomers such as acrylic acid, methacrylic acid, maleic acid or the like, or acrylic acid esters thereof, Examples thereof include copolymers copolymerized with monomers such as methacrylic acid esters. Specifically, SMA-1000, S
MA-2000, SMA-3000 (above, manufactured by Arco Chemical Co., Ltd.), John Cryl-67 (manufactured by Johnson Polymer Co., Ltd.), CB-MHP, CB-1 (manufactured by Shin-Nakamura Chemical Co., Ltd.), HOA-MPL ( Kyoeisha Yushi Co., Ltd.,
Viscoat # 2 100 (Osaka Organic Chemical Industry Co., Ltd.)
Can be given.

Further, examples of the novolak resin include phenol resin, cresol resin and alkylphenol resin which are soluble in an alkaline aqueous solution. Specifically, phenol novolac resin includes BRG-556, BRG
-557 (manufactured by Showa High Polymer Co., Ltd.) and Resin X (manufactured by Mitsubishi Petrochemical Co., Ltd.). Cresol novolac resin has P
SM-2246, PSM-4402 (above, Gunei Chemical Co., Ltd. make) etc. are mentioned. Further, examples of the alkylphenol resin include MCM-709 and MCM-726 (all manufactured by Showa High Polymer Co., Ltd.).

As the solvent-soluble resin, phenol-based resin,
Examples thereof include xylene type, urea type, melamine type, epoxy type, alkyd type, vinyl type, acrylic type, chlorinated rubber type, polyamide type, terpene type, butyral type, cyclized rubber type, ketone type and cellulose derivatives. Among these, heat-plasticizing resins such as rubber-based and cellulose derivatives are particularly preferable.

Phenolic resins include resol-type phenolic resins and novolac-type phenolic resins. Specifically, the resole-type phenolic resins include Super Beckasite 1001,
As the novolac type, Super Beckasite 3011 (manufactured by Dainippon Ink and Chemicals, Inc.) can be mentioned.

The urea type includes butylated urea resin, and specific examples thereof include Uban 10S-60 (above, manufactured by Mitsui Toatsu Chemicals, Inc.). The melamine system includes hexamethoxymethylol melamine, methylated melamine, etc.,
Specifically, as hexamethoxymethylol melamine, Cymel 300 (manufactured by Mitsui Toatsu Chemicals, Inc.), Nikarac MW-30 (manufactured by Sanwa Chemical Co., Ltd.), and as methylated melamine, Cymel 301 (Mitsui East). Pressure Chemical Co., Ltd.
Made).

Alkyd resins include alkyd resins and modified alkyd resins. Among the alkyd resins, Becksol Z-557 (manufactured by Dainippon Ink and Chemicals, Inc.),
Examples of the modified alkyd resin include Beckosol J-611 and Styresol 4440 (all manufactured by Dainippon Ink and Chemicals, Inc.).

For butyral resin, S-REC BL-
1 (manufactured by Sekisui Chemical Co., Ltd.), Denka Butyral # 60
00-C (manufactured by Denki Kagaku Kogyo Co., Ltd.). Epoxy acrylate and urethane acrylate are particularly preferable for a solder resist which is hardened in a short time and is required to have electric insulation, heat resistance, hardness, adhesion and chemical resistance. The content of the alkali- or solvent-soluble resin is preferably 10 to 50 wt% with respect to the solid content of the ink.

A curing agent is used for the first solder resist ink. The curing agent is appropriately selected according to the thermosetting resin to be used. For example, in the case of epoxy resin, 1 is selected from amine compounds, acid anhydride compounds, phenol resins, polyamide resins and imidazoles. One kind or two or more kinds are used. After the use of these curing agents, they may be used in a usual amount depending on the type and required gelling time. In the epoxy resin, a curing accelerator may be used together with the above curing agent, and examples thereof include dicyandiamide, imidazoles, amines, and tertiary amines.

Furthermore, the first solder resist ink may be added with a filler, a coloring pigment, a defoaming agent, a peroxide, a thixotropic agent, a leveling agent, an adhesion-imparting agent or the like.

The above first solder resist ink is used as a general resin filler such as silicon dioxide, aluminum silicate, magnesium silicate, aluminum hydroxide and barium sulfate as a filler for imparting screen printing characteristics. What is used can be included. The amount used is 3 to 90 wt% with respect to the total amount of the alkali or solvent-soluble resin, preferably 10 to
It is preferably 30 wt% and the average particle size thereof is 15 μm or less.

In the present invention, the second solder resist ink used in the second step contains a curable resin curable by ultraviolet rays and heat, and a known photocurable resin is used. More specifically, examples thereof include acrylic acrylate oligomers such as polyol acrylate, polyester acrylate, urethane acrylate, epoxy acrylate, polyether acrylate, and melamine acrylate, and resins such as photocurable unsaturated polyester.

The second solder resist ink contains a photosensitive diluent and a photopolymerization initiator.

The photo-sensitive diluent is one that dissolves the resin and photo-polymerizes, and a known photo-sensitive diluent corresponding to the resin used is used. Typically, a vinyl monomer having an ethylenically unsaturated double bond, methoxyethyl acrylate (or methacrylate), ethoxyethyl acrylate (or methacrylate), butoxyethyl acrylate (or methacrylate), methoxyethoxyethyl acrylate (or methacrylate). ), Stearyl acrylate (or methacrylate), lauryl acrylate (or methacrylate),
Tetrahydrofurfuryl acrylate (or methacrylate), benzyl acrylate (or methacrylate), phenoxyethyl acrylate (or methacrylate), 2-hydroxyethyl acryloyl (or methacryloyl) phosphate, 2-hydroxyethyl acrylate (or methacrylate), 2-hydroxypropyl acrylate (Or methacrylate), ethylene glycol diacrylate (or dimethacrylate), diethylene glycol diacrylate (or dimethacrylate), triethylene glycol diacrylate (or methacrylate), polyethylene glycol diacrylate (or dimethacrylate), propylene glycol diacrylate (or Dimethacrylate), polypropylene glycol diac Rate (or dimethacrylate), 1,6-hexanediol diacrylate (or dimethacrylate), trimethylolpropane triacrylate (or trimethacrylate), 2-ethylhexyl acrylate (or methacrylate), 1,3-butylene glycol diacrylate ( Or dimethacrylate), 1,4-butylene glycol diacrylate (or dimethacrylate), neobetyl glycol diacrylate (or dimethacrylate), dipropylene glycol diacrylate (or dimethacrylate), tetramethylol methane triacrylate (or trimethacrylate). Methacrylate), tetramethylolmethane tetraacrylate (or tetramethacrylate), neopentyl glycol diacrylate hydroxypivalate ( The dimethacrylate), dipentaerythritol hexaacrylate (or hexa methacrylate), hydroxyalkyl acrylates (or methacrylates) semi esterified products of polybasic acids (or their anhydrides) and the like. The content of these is not particularly limited, but is preferably in the range of 10 to 40% by weight based on the total solid content of the ink.

Examples of the photopolymerization initiator include α-carbonyl alcohols such as benzoin, bunaroin, trioin and acetoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, pivaloin ethyl ether and anisoinethyl. Acyloin ethers such as ethers, α-methylbenzoin, α-side chain acylosins such as α-phenylbenzoin, 9,10-anthraquinone, 2-chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 1,4 -Polycyclic quinones such as naphthoquinone and 2,3-benzanthraquinone,
Substituted polyketone compounds such as diacetyl, dibenzoyl, diphenylketone, phenylglyoxal, pentadione-2,3,1-phenylbutanedione-1,2, octadione-2,3, diphenyltriketone, benzophenone, α-promoacetophenone, 2 -Hydroxyne-2-methylpropiophenone, 4'-isopropyl-2-hydroxy-2-methylpropiophenone, 2,
2-dimethoxy-2-phenylacetophenone, p-ter
t-butyltrichloroacetophenone, p-tert-
Aromatic ketones such as butyl monochloroacetophenone, 2,2-diethoxyacetophenone, and 4,4'-bis-dialkylaminobenzophenones are listed.

The second solder resist ink is
As with the first solder resist ink, additives such as a filler, a coloring pigment, a defoaming agent, a peroxide, a thixotropic agent, a leveling agent or an adhesion-imparting agent may be added. Examples of the solvent used for the developing treatment in the third step include petroleum carbitol acetate and trichloroethane. As the alkaline aqueous solution, a caustic soda aqueous solution, a sodium carbonate aqueous solution, a sodium metasilicate aqueous solution or the like can be used.

[0029]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition, "parts" means "parts by weight" unless otherwise specified. Example 1 The first solder resist ink composition was applied by screen printing on the entire surface of a printed wiring board on which a conductor circuit was formed and dried to form an alkali-soluble first solder resist film, and the temperature was kept at 80 ° C., 20 ° C. Dry for minutes. The first solder resist ink composition used here has the following composition. Styrene-maleic acid resin 30 parts (SMA-1440, Alco Chemical Co., Ltd.) Trisepoxypropyl isocyanurate 10 parts (TEPIC Nissan Chemical Co., Ltd.) Carbitol acetate 20 parts (Jukizol CA, Osaka Organic Chemical Industry Co., Ltd.) Barium sulfate 28 parts Petroleum naphtha 12 parts (Solvesso # 150, Asahi Kasei Corporation)

Next, on the above-mentioned solder resist film,
As the second solder resist ink, an ultraviolet curable solder resist (UVR-150G, manufactured by Taiyo Ink Mfg. Co., Ltd.) was screen printed to a thickness of 15 μm to 20 μm. Then, the irradiation device used in screen printing was used to cure the coating film with a light amount of 1000 mJ / cm ² . After curing, it was developed with a 1% aqueous solution of sodium carbonate for 30 seconds and thermally cured at 150 ° C. for 30 minutes to obtain a solder resist pattern. The printed solder pattern had no bleeding and no edge breakage because there was no copper foil step. The same effect was obtained even when a thermosetting solder resist (SGR-100, manufactured by Taiyo Ink Mfg. Co., Ltd.) was used as the second solder resist ink. As described above, the characteristics of the embodiment of the present invention are shown in Table 1 below in comparison with the conventional example.

[0031]

[Table 1]

[0032]

As shown in Table 1 above, the present invention exhibits higher accuracy than the screen printing method, and the productivity is the same as that of the screen printing method. Suitable for manufacturing solder masks for wiring boards. The printed wiring board obtained according to the present invention has a solder resist layer having two layers, that is, a solder resist film and a solder resist pattern. Since the characteristics are obtained, it is also useful as an intermediate layer of a power supply board and an EMI shield board. Furthermore, according to the present invention, by selecting the solder resist film and the solder resist pattern,
A wide range of applications from industrial double-sided through-hole boards to consumer single-sided boards are possible.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a pattern forming process for forming a solder resist pattern of the present invention.

[Explanation of symbols]

 1 substrate 2 conductor circuit 3 solder resist film

Claims (1)

[Claims] (1) A first solder resist ink is applied to the entire surface of a printed circuit board on which a conductor circuit is formed and is temporarily dried by heat to form a solder resist film soluble in an alkaline aqueous solution or an organic solvent. Step (2) pattern printing with a second solder resist ink on the formed solder resist film and curing with ultraviolet rays, (3) developing with an aqueous alkali solution or organic solvent, and (4) ) A method of manufacturing a printed wiring board having a solder resist pattern formed on a conductor circuit, comprising the step of heating the formed solder resist pattern and post-curing the same.