JPH07175216A - Photosolder resist composition - Google Patents

Abstract

PURPOSE:To provide an alkali developing photosolder resist composition having excellent property in exposure sensitivity, resolution, chemical resistance, solvent resistance and the like and excellent in workability and preservable stability. CONSTITUTION:The photosolder resist composition contains a whole half esterified compound (A) of a high polymer of an unsaturated polybasic acid or its anhydride or the copolymer of another ethylene unsaturated compound with a monohydric alcohol having >=70 hydroxyl group equivalent and an ethylene unsaturated compound (B). The usable time after mixing two liquids, namely the pot life, is extremely improved, the change of the viscosity after preparing is eliminated and the preservable stability is excellent. And the composition shows excellent property in exposure sensitivity and resolution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photo solder resist which is preferably used in a printed wiring board manufacturing process and the like. Specifically, a photo solder that forms a pattern by irradiation with radiation such as ultraviolet rays and exhibits excellent heat resistance, chemical resistance, water resistance, moisture resistance, solvent resistance and electrical insulation after development with a weak alkaline aqueous solution. The present invention relates to a resist composition.

[0002]

2. Description of the Related Art Solder resists are indispensable materials in printed wiring board manufacturing as a protective film for preventing solder from adhering to unnecessary portions in a soldering process and as a permanent mask. Conventionally, a thermosetting type resist is often used as a solder resist, and a method of printing this by a screen printing method has been generally used. However, with the recent increase in the density of wiring on a printed wiring board, the screen printing method is used. However, there is a limit in resolution, and photo solder resists, which are pattern-formed by a photographic method, are widely used.

However, since the conventional photo solder resist uses a harmful organic solvent such as 1,1,1-trichloroethane at the time of development, problems such as influence on the human body and environmental pollution cannot be avoided. Further, in recent years, an alkali developing type capable of developing with a weak alkaline solution such as a sodium carbonate solution is appearing, but it is still insufficient in terms of characteristics such as exposure sensitivity, resolution, chemical resistance, and solvent resistance. It can't be said to be naive.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an alkali development having excellent characteristics such as exposure sensitivity, resolution, chemical resistance and solvent resistance, and having good workability and storage stability. To provide a photo-solder resist composition of the present invention.

[0005]

That is, the present invention is
(A) Half-esterified product of a polymer of unsaturated polybasic acid or anhydride thereof or a copolymer with another ethylenically unsaturated compound by a monohydric alcohol having a hydroxyl equivalent of 70 or more, and (B) an ethylenically unsaturated compound A photosolder resist composition comprising:

(A) A half-esterified product of a polymer of an unsaturated polybasic acid or an anhydride thereof or a copolymer with another ethylenically unsaturated compound by a monohydric alcohol having a hydroxyl equivalent of 70 or more is negative during exposure. It has a film-forming action to form a tack-free film that can adhere the film, and is necessary to make it soluble in a weak alkaline solution such as an aqueous solution of sodium carbonate used for development. (A) is used in the range of 10 to 95% by weight in the photo solder resist composition. Examples of the unsaturated polybasic acid or its anhydride used as a component of the polymer or copolymer which is the precursor of (A) include maleic acid, itaconic acid, maleic anhydride, itaconic anhydride and the like.

The unsaturated polybasic acid or its anhydride is
You may copolymerize with other ethylenically unsaturated compounds, such as an acrylic monomer and a vinyl monomer. As the acrylic monomer, (meth) acrylic acid alkyl ester,
Examples thereof include, but are not limited to, (meth) acrylic acid hydroxyalkyl ester, acrylamide, alkylated acrylamide, alkylolated acrylamide, and acrylonitrile. Examples of vinyl monomers include ethylene, propylene, n-butene, isobutene,
Butadiene, α-olefin, vinyl chloride, isoprene, chloroprene, styrene, α-alkylstyrene,
Examples thereof include ring-substituted styrene, alkyl vinyl ether, vinyl acetate, allyl alcohol and the like, but are not limited thereto. These may be used alone or in combination of two or more.

The monohydric alcohol used in (A) must have a hydroxyl group equivalent of 70 or more. Hydroxyl equivalent is 70
When a monohydric alcohol of less than 1 is used, overdevelopment is likely to occur during development, and phenomena such as surface roughening, undercutting, fine line portions or overall peeling occur, and the desired resist film cannot be obtained. The monohydric alcohol is not particularly limited as long as the hydroxyl equivalent is 70 or more, and may have a functional group other than the alcoholic hydroxyl group. Moreover, you may have an ethylenically unsaturated group. The amount of monohydric alcohol used must be equal to or more than the equivalent amount of the acid anhydride group of the precursor. If it is less than the equivalent, acid anhydride groups remain, which adversely affects various properties. That is, the usable time (pot life) after mixing the two liquids and the time allowed to stand from prebaking to development are shortened. In addition, the residual acid anhydride group easily reacts with moisture in the air, which causes a change in viscosity during storage.

As the monohydric alcohol having a hydroxyl equivalent of 70 or more, an alkanol having 4 or more carbon atoms (having a hydroxyl equivalent of 74.12 or more, which may be linear or branched), benzyl alcohol (108.14), ethylene glycol Monoacetate (104.11), glycolic acid (76.05), hydroxyphenethyl alcohol (138.17), furfuryl alcohol (98.10), hydroxyalkyl (meth)
Acrylate (116.12 or above), polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polycaprolactone mono (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane di (meth) acrylate, neopentyl Glycol mono (meth) acrylate, 1,6-hexanediol mono (meth) acrylate
Examples thereof include, but are not limited to, acrylate, tetramethylolmethane tri (meth) acrylate, di (2- (meth) acryloyloxyethyl) acid phosphate, glycerol di (meth) acrylate and the like. Also,
These may be used alone or in combination of two or more.

The ethylenically unsaturated compound (B) is necessary for imparting curability by active energy rays, and is used in the range of 5 to 90% by weight in the photo solder resist composition. By using (B), a portion selectively irradiated with active energy rays such as ultraviolet rays, electron beams, and X-rays becomes an insoluble three-dimensional crosslinked product due to the addition reaction of the unsaturated double bond. On the other hand, the part that was not irradiated with active light is in a state of retaining alkali solubility,
An image is formed by developing with an alkaline solution.

The ethylenically unsaturated compound (B) is not particularly limited, but ethyl (meth) acrylate, butyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, styrene. , Α-alkylstyrene, oligoester (meth) monoacrylate, (meth) acrylates such as (meth) acrylic acid, ethylene glycol di (meth) acrylate, polyethylene glycol diacrylate, neopentyl glycol (meth) acrylate,
Tetramethylolmethane di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 2-hydroxy
-1- (meth) acryloxy-3- (meth) acrylate, urethane (meth) acrylate, diallyl phthalates, etc.
Alternatively, a mixture of these can be used.

In the photo solder resist composition of the present invention, in addition to the above components (A) and (B), the physical properties are improved,
For the purpose of improving workability and storage stability, the following components (C) to (G) can be used, if necessary. (C) Photopolymerization initiator and / or photopolymerization accelerator (D) Compound having one or more epoxy groups (E) Latent thermosetting agent, thermosetting agent solid at room temperature, thermosetting accelerator One or more kinds (F) One or more kinds selected from organic solvent and water (G) Other additives

The (C) photopolymerization initiator and / or the photopolymerization accelerator is necessary when the active energy ray used for photopolymerization is ultraviolet light, and is 0 to 20 in the photosolder resist composition. It can be used in the range of% by weight. As the photopolymerization initiator, benzophenone, methylbenzophenone, o-benzoylbenzoic acid, benzoylethyl ether, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,2 -Diethoxyacetophenone, 2,4-diethylthioxanthone and the like, and examples of the photopolymerization accelerator include isoamyl p-dimethylbenzoate, 4,4-bis (diethylamino) benzophenone and dimethylethanolamine.

The compound (D) having one or more epoxy groups is contained in the photo solder resist composition in an amount of 0 to 50 in order to improve performances such as film strength, heat resistance, durability, chemical resistance and environmental resistance. It can be used in the range of% by weight. As such, one or more selected from triglycidyl isocyanurate, hydroquinone diglycidyl ether, bisphenol diglycidyl ether, cresol novolac type epoxy resin and phenol novolac type epoxy resin are reactive,
Most preferred in terms of physical properties and storage stability. As the cresol novolac type epoxy resin, "Epiclon N-695" manufactured by Dainippon Ink and Chemicals, Inc., as the phenol novolac type epoxy resin, "Epiclon N-775" manufactured by Dainippon Ink and Chemicals, Inc. Epoxy Co., Ltd. "Epicoat 152" and "Epicoat 154", Dow
"DEN431" and "DEN438" manufactured by Chemical Co., "EPN1138" manufactured by Ciba Co., Ltd., and the like, and triglycidyl isocyanurate include "TEPIC-G" manufactured by Nissan Chemical Industries, Ltd.,
"TEPIC-S" and "TEPIC-P" and the like are bisphenol diglycidyl ether as "Epicoat 828", "Epicoat 1001" manufactured by Yuka Shell Epoxy Co., Ltd.,
Examples include, but are not limited to, "Epicoat 1004", "Epicoat 1007", "Epicoat 1009", and the like.

(E) When one or more selected from latent heat curing agents, heat curing agents solid at room temperature, and heat curing accelerators are used, conventionally known compounds such as "new epoxy resin" are used. (Published by Shokodo, May 1985), pages 164 to 263 and 356 to 405, "Crosslinker Handbook" (published by Taisei Co., October 1981), pages 606 to 655 Among these, those having good storage stability are selected.
(E) can be used in the range of 0 to 10% by weight in the photo solder resist composition. As the latent thermosetting agent, boron trifluoride-amine complex, dicyandiamide (DICY) and its derivatives, organic acid hydrazide,
Diaminomaleonitrile (DAMN) and its derivatives, melamine and its derivatives, guanamine and its derivatives, amine imide
(AI), polyamine salts, etc.

As the thermosetting agent which is solid at room temperature, metaphenylenediamine (MP-DA), diaminodiphenylmethane (D
DM), diaminodiphenyl sulfone (DDS), aromatic amines such as "Hardener HT972" manufactured by Ciba-Geigy, phthalic anhydride, trimellitic anhydride, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydrotrimerate) Melitate), aromatic acid anhydrides such as 3,3 ′, 4,4′-benzophenone tetracarboxylic acid anhydride, maleic anhydride, succinic anhydride, and cyclic aliphatic acid anhydrides such as tetrahydrophthalic anhydride. is there. Examples of thermosetting accelerators are metal salts of acetylacetone such as acetylacetonate Zn and acetylacetonate Cr, enamine, tin octylate, quaternary phosphonium salts, triphenylphosphine, 1,8-diazabicyclo (5,4,0) Undecene-7 and its 2-ethylhexanoate and phenol salts, imidazole, imidazolium salts, triethanolamine borate and the like can be mentioned.

(F) One or more selected from organic solvents and water dissolves or disperses each component of the photo solder resist composition of the present invention, and for the purpose of adjusting the viscosity, the photo solder resist composition. It is used in the range of 0 to 70% by weight. (F) is appropriately selected in consideration of solubility, dispersibility, boiling point, influence on human body, etc. of each component.

(G) Other additives may be used, if necessary, within a range that does not impair the performance of the photo solder resist composition of the present invention, that is, within a range of 0 to 60% by weight in the photo solder resist composition. it can. Other additives include dyes and pigments for making it easier to confirm the coating state,
Thixotropic agent for adjusting fluidity, extender pigment for adjusting viscosity and facilitating development, polymerization inhibitor for preventing dark reaction and improving storage stability, adhesion improver, silane coupling Agents, antioxidants, defoamers, thermal polymerization initiators, etc., but are not limited to these.
Examples of dyes and pigments include phthalocyanine green and titanium white, and examples of thixotropic agents include finely divided silica. Examples of extender pigments include silica, talc, magnesium carbonate, calcium carbonate, natural mica, synthetic mica, aluminum hydroxide, precipitated barium carbonate, barium titanate and the like. Examples of the polymerization inhibitor include hydroquinone and phenothiazine, and examples of the defoaming agent include silicone type, hydrocarbon type, acrylic type and the like.

The above (A), (B) and, if necessary, (C) to (G) are mixed, and if necessary, three rolls,
The photo solder resist composition of the present invention is obtained by kneading or mixing with a kneading means such as a ball mill or a sand mill, or a stirring means such as a super mixer or a planetary mixer. The obtained photo solder resist composition is applied on a printed wiring board on which a copper circuit is formed with a coating film thickness of about 5 to 100 μm. As the coating means, the entire surface printing by the screen printing method is generally used at present, but any coating means including this can be used as long as it can be coated uniformly. For example, spray coater, hot melt coater, bar coater, applicator, blade coater, knife coater,
An air knife coater, a curtain flow coater, a roll coater, a gravure coater, offset printing, dip coating, brush coating, and any other ordinary method can be used.

After coating, if necessary, prebaking, that is, temporary drying is performed in a hot air oven or a far infrared oven to make the surface tack-free. The prebaking temperature is preferably about 50 to 100 ° C. Next, exposure with active energy rays is performed using a negative mask in which only the portions to be plated with solder do not pass the active energy rays. As the negative mask, a negative film is used when the active energy rays are ultraviolet rays, a metallic mask is used when the active energy rays are ultraviolet rays, and a lead mask is used when the active energy rays are X-rays, but a simple negative film can be used. Therefore, ultraviolet rays are often used as active energy rays in the production of printed wiring boards. The irradiation dose of ultraviolet rays is about 10 to 1000 mJ / cm ² .

After the exposure, a weak alkaline solution such as dilute aqueous solution of sodium carbonate is used as a developing solution and development is performed by means such as spraying and dipping, and the unexposed portion is removed by the action of dissolution, swelling, peeling and the like. Next, heat in a hot air oven or a far infrared oven,
Alternatively, post-curing is performed by UV irradiation. The photo solder resist is applied through the above steps.

[0022]

EXAMPLES Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the scope of rights of the present invention. In the examples, "part" means "part by weight" and "%" means "% by weight".

[Synthesis Example 1] Styrene / maleic anhydride copolymer ("Admast 1000" manufactured by Idemitsu Petrochemical Co., Ltd., average molecular weight 6,500, maleic anhydride content 50 mol%) 369.
9g, cellosolve acetate 226.6g, triethylamine 4.
2 g and hydroquinone (0.7 g) were charged in a flask, the temperature was raised to 90 ° C., 1.2 equivalents of benzyl alcohol (220.4 g) was added dropwise to the maleic anhydride residue over 30 minutes, and then the reaction was carried out for 6 hours. Bubbling was continued during the reaction. Solid content 5
A resin product (a1) having 3.2% and an acid value of 181 mgKOH / g was obtained.

Synthesis Example 2 Styrene / maleic anhydride copolymer "Admast 1000" 369.9 g, cellosolve acetate 226.6 g, triethylamine 4.2 g, hydroquinone 0.7 g
Was charged into a flask, the temperature was raised to 90 ° C., 1.0 equivalent of ethylene glycol monoacetate (176.8 g) was added dropwise to the maleic anhydride residue over 30 minutes, and then the reaction was carried out for 6 hours. Bubbling was continued during the reaction. A resin product (a2) having a solid content of 57.4% and an acid value of 176 mgKOH / g was obtained.

[Synthesis Example 3] Styrene / maleic anhydride copolymer "Admast 1000" 369.9 g, cellosolve acetate 226.6 g, triethylamine 4.2 g, hydroquinone 0.7 g
Was charged into a flask, the temperature was raised to 90 ° C., and 0.25 equivalent of 2-hydroxyethyl methacrylate (55.2 g) was added dropwise to the maleic anhydride residue over 30 minutes. Next, 0.75 equivalents of ethylene glycol monoacetate (132.6 g) was added dropwise to the maleic anhydride residue over 30 minutes, and then the reaction was carried out for 6 hours. Bubbling was continued during the reaction. Solid content 52.2
%, An acid value of 173 mg KOH / g of a resin product (a3) was obtained.

[Synthesis Example 4] Styrene / maleic anhydride copolymer "Admast 1000" 369.9 g, cellosolve acetate 226.6 g, triethylamine 4.2 g, hydroquinone 0.7 g
Was charged into a flask, the temperature was raised to 90 ° C., 0.7 equivalent of 2-hydroxyethyl methacrylate (154.7 g) was added dropwise to the maleic anhydride residue over 30 minutes, and then the reaction was carried out for 6 hours. Bubbling was continued during the reaction. A resin product (R1) having a solid content of 55.2% and an acid value of 134 mgKOH / g was obtained.

[Synthesis Example 5] Styrene / maleic anhydride copolymer "Admast 1000" 369.9 g, cellosolve acetate 226.6 g, triethylamine 4.2 g, hydroquinone 0.7 g
Was charged into a flask, the temperature was raised to 90 ° C., and 0.5 equivalent of 2-hydroxyethyl methacrylate (110.5 g) was added dropwise to the maleic anhydride residue over 30 minutes. Next, 0.6 equivalent of ethanol (46.9 g, hydroxyl equivalent of 46.07) was added dropwise to the maleic anhydride residue over 30 minutes, and then the mixture was reacted for 6 hours. Bubbling was continued during the reaction. A resin product (R1) having a solid content of 52.2% and an acid value of 193 mgKOH / g was obtained.

Example 1 A photo solder resist composition having the following formulation was prepared. (A), (C), (E), (G1), (G
2) and (G3) were premixed and then thoroughly kneaded with a three-roll mill. (D) is dissolved in (F) in advance, and (B), (G
The kneaded product was mixed with 4) in a small planetary mixer. (A) Resin product (a1) 500 parts (B) Ethylenically unsaturated compound trimethylolpropane triacrylate (“NK Ester A-TMPT” manufactured by Shin Nakamura Chemical Co., Ltd.) 155 parts (C) Photopolymerization initiator 2, 4-Diethylthioxanthone 52 parts (D) Epoxy compound Cresol novolac type epoxy 120 parts ("Epiclone N-695" manufactured by Dainippon Ink and Chemicals, Inc.) (E) Latent heat curing agent dicyandiamide 5 parts (F) Solvent Cellosolve Acetate 100 parts (G1) Coloring material Copper phthalocyanine green 5 parts (Toyo Ink Mfg. Co., Ltd. “Rionol Green 2YS”) (G2) Thixotropic agent Fine silica 40 parts (Nippushiru N-300A manufactured by Nippon Silica Industry Co., Ltd.) )) (G3) Body pigment Talc (manufactured by Fuji Talc Co., Ltd.) 120 parts (G4) Defoamer Silicone 16 parts (Toray Dow) Ningu Silicone Co., Ltd.)

The photosolder resist composition thus obtained was evaluated by the following test methods using the following two types of test bodies. The results are shown in Table 1. The conditions of each step were as follows, unless otherwise specified. Specimen 1: Copper-clad laminate (FR-4) Specimen 2: Printed wiring board for testing (FR-4, minimum circuit width
0.1mm (4 between pins))

Coating: Screen printing method, whole surface coating using 150 mesh Tetron plate Prebaking: Circulating hot air oven used, 75 ° C / 30 minutes Exposure: "HMW680GW" manufactured by Oak Co., Ltd. (using 2 7kw metal halide lamps) Exposure intensity 35mW / cm ² (wavelength 365
Exposure (in nm) 300 mJ / cm ² Development: 1% sodium carbonate aqueous solution, liquid temperature 30 ° C., spray pressure 3 kg / cm ² , time 60 seconds, shower water washing 30 seconds Post cure: circulating hot air stove, 140 ° C./40 Minute

○ Pot life test The photo solder resist composition which had been left for 24, 48, 72, 96, and 120 hours after preparation was applied to the test body 1 and prebaked. After 10 minutes from the pre-baking, development was performed and the developability was evaluated. The evaluation criteria are shown below. ○ ---- Fully developed □ ---- Slight development residue (to the extent that no green color remains) △ ---- Clear development residue (green color remains) ×- --Almost not developed

○ Storage stability test The kneaded meat composition before adding (D) and (F) after kneading with three rolls was stored in a thermostatic chamber at 25 ° C for 0, 7, 14, 21, 28 days. Each time, a solution of (D) in (F) was added to prepare a photo solder resist composition, and the viscosity was measured by a rotary viscometer. A graph of viscosity change is shown in FIG.

○ Active energy ray curability test A photo solder resist composition immediately after preparation was applied to a test body 2 and exposure was performed. The exposure was carried out at an exposure dose of 50 mJ / cm ² using a negative film for exclusive use, and development was carried out 10 minutes after the exposure. The development time was 120 seconds, and the surface condition after development was observed. The evaluation criteria are shown below. 5 ---- No change 4 ---- Decrease in surface gloss 3 ---- Rough surface roughness 2 ---- Peeling of film 1 ---- Almost no film remains Peeling

Resolution Test A test body 1 was coated with the photosolder resist composition immediately after preparation and exposure was performed. For exposure, a line and space negative film with a minimum width of 50 μm is used, and the exposure amount is 15
It was performed at 0 mJ / cm ² . After 10 minutes of exposure, development was carried out for a development time of 120 seconds, and it was observed how many μm the width remained.

Acid resistance test The photo solder resist composition immediately after preparation was applied to the test body 2 and post cure was performed. A dedicated negative film was used during exposure. The prepared test body was dipped in a 10% sulfuric acid aqueous solution for 1 hour, washed thoroughly with water, sufficiently wiped of water, and then subjected to cellophane peeling at a portion having a minimum circuit width.
The evaluation criteria are shown below. 5 ---- No peeling at all 4 ---- Slight peeling (approximately 5% or less) 3 ---- Partial peeling (approximately 20% or less) 2 ---- Wide range of peeling (generally) 20% or more) 1 ---- Complete peeling

[Examples 2 to 3] Resin products (a1) to (a2)
Photosolder resist compositions changed to (a3) were prepared in the same manner as in Example 1 and evaluated in the same manner. The results are shown in Table 1. [Comparative Examples 1 and 2] Photosolder resist compositions in which the resin products (a1) were changed to (R1) to (R2) were prepared in the same manner as in Example 1 and evaluated in the same manner. The results are shown in Table 1.

[0037]

[Table 1]

[0038]

EFFECTS OF THE INVENTION According to the present invention, it is possible to develop with a weak alkaline aqueous solution without using a harmful organic solvent and the like, the workability is high, and the excellent characteristics such as resolution, chemical resistance and solvent resistance are provided. A photo solder resist composition having the above was obtained. INDUSTRIAL APPLICABILITY The photo solder resist composition of the present invention has a greatly improved pot life after mixing two liquids, that is, a pot life, has almost no change in viscosity after preparation, and is excellent in storage stability. It also exhibits excellent properties in exposure sensitivity and resolution.

[0039]

[Brief description of drawings]

FIG. 1 is a graph showing the storage stability test results.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display H05K 3/28 D

Claims (1)

[Claims] 1. A half-esterified product of (A) a polymer of an unsaturated polybasic acid or an anhydride thereof or a copolymer thereof with another ethylenically unsaturated compound by a monohydric alcohol having a hydroxyl equivalent of 70 or more, and ( B) A photo solder resist composition comprising an ethylenically unsaturated compound.