JPH1184652A - Photosensitive resin composition and photosensitive element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photosensitive resin compsn. having particularly superior adhesion, resolution, flexibility, film strength and film elongation as an etching or plating resist by incorporating a specified film property imparting polymer, an ethylenically unsatd. compd. and a photopolymn. initiator. SOLUTION: The photosensitive resin compsn. contains 50-70 pts.wt. film property imparting polymer having a wt. average mol.wt. to number average mol.wt. ratio (dispersity) of 2.0-3.0 obtd. by copolymerizing 10-15 wt.% (meth) acrylic acid and 85-90 wt.% compd. represented by the formula as copolymerizable components, 3050 pts.wt. ethylenically unsatd. compd. and 0.5-10 pts.wt. photopolymn. initiator based on 100 pts.wt., in total, of the polymer and the unsatd. compd. and further contains a plasticizer and a pigment or dye. In the formula, R<1> is H or methyl and R<2> is 1-12C alkyl.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photosensitive resin composition,
More specifically, a photosensitive resin composition having particularly excellent adhesion, resolution, flexibility, film strength, and film elongation as an etching resist or a plating resist used for production of printed wiring boards, precision processing of metals, and the like. And a photosensitive element using the same.

[0002]

2. Description of the Related Art Conventionally, in the fields of production of printed wiring boards, precision processing of metals, etc., as a resist material used for etching, plating, etc., a photosensitive resin composition and a film formed on a support, A photosensitive element provided with a protective film thereon is widely used. Printed wiring board, after laminating a photosensitive film obtained using the photosensitive resin composition or the photosensitive element on a copper substrate, pattern exposure, unexposed portions are removed with a developer,
It is manufactured by a method in which a pattern is formed by etching or plating, and then a cured portion is peeled off from the substrate.

As a developer for removing the unexposed portions, an alkali developing type using an aqueous solution of sodium carbonate or the like is mainly used.

In recent years, with the increase in density of printed wiring boards,
There are many defects due to scattering of resist chips generated when laminating the photosensitive film, defects due to insufficient adhesion of the photosensitive film to the substrate and insufficient resolution, and defects due to insufficient resist film strength and film elongation. In order to prevent the occurrence of these defects, it is necessary to improve the adhesion, resolution, flexibility, film strength and film elongation of the photosensitive resin composition to the substrate.

[0005] This kind of photosensitive resin composition or photosensitive element is disclosed in Japanese Patent Publication No. 1-5691 and Japanese Patent Publication No. 52-94.
388, JP-B-54-25957 and JP-B-54-34372. However, although the above-mentioned photosensitive resin composition is very useful for the intended purpose, adhesion, resolution, flexibility, film strength and film elongation that can respond to the recent increase in the density of printed wiring boards are considered. Do not have.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and is particularly excellent as an etching resist or a plating resist used for manufacturing printed wiring boards, precision processing of metals, and the like. An object of the present invention is to provide a photosensitive resin composition having excellent adhesion, resolution, flexibility, film strength, and film elongation, and a photosensitive element using the same.

[0007]

That is, the present invention provides:
(A) (meth) acrylic acid 10 to 15% by weight and 85 to 90% by weight of a compound represented by the general formula [I] are copolymerized as a copolymer component to have a weight average molecular weight of 30,0.
50 to 70 parts by weight of a film-imparting polymer having a weight average molecular weight / number average molecular weight (dispersion degree) of 2.0 to 3.0;

[0008]

Embedded image (In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 1 to 12 carbon atoms.) (B) 30 to 50 parts by weight of an ethylenically unsaturated compound (provided that the component (A) And the total amount of component (B) is 100 parts by weight.), (C) 0.5 to 10 parts by weight of photopolymerization initiator based on 100 parts by weight of total amount of components (A) and (B).
Parts by weight, 1.0 to 10 parts by weight of the plasticizer (D) based on 100 parts by weight of the total of the components (A) and (B), and (E) the pigment or dye as the components (A) and (B). The present invention provides a photosensitive resin composition containing 0.01 to 3.0 parts by weight based on 100 parts by weight of the total amount.

The present invention also provides a photosensitive element obtained by applying the above-mentioned photosensitive resin composition on a support and drying it.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The (meth) acrylic acid which is a copolymer component of the film-imparting polymer (A) used in the present invention means methacrylic acid and / or acrylic acid.

The compound represented by the general formula [I] includes
For example, (meth) acrylic acid methyl ester, (meth)
Ethyl acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylate
Examples thereof include amyl acrylate, hexyl (meth) acrylate, and octyl (meth) acrylate.

The film-imparting polymer of the component (A) is preferably soluble or swellable in an aqueous alkali solution (for example, 0.5 to 2.0% by weight aqueous solution of sodium carbonate or potassium carbonate). The copolymerization amount of (meth) acrylic acid in the copolymerization component of the polymer is 10 to 15
%, Preferably 11 to 14% by weight. If the copolymerization amount of (meth) acrylic acid in the film-imparting polymer exceeds 15% by weight, the adhesiveness is reduced, and 10% by weight
If it is less than 1, the developing time becomes longer and the resolution decreases.

The weight average molecular weight of the film-imparting polymer is from 30,000 to 70,000, preferably from 40,000 to 60,000. When the weight average molecular weight of the film-imparting polymer exceeds 70,000, the development time is prolonged and the resolution is lowered, and
If it is less than 0, the adhesiveness decreases and the film strength decreases. Further, the degree of dispersion of the film-imparting polymer is 2.0 to
3.0, and preferably 2.2 to 2.8. When the degree of dispersion of the film-imparting polymer exceeds 3.0, the resolution decreases, and when it is less than 2.0, the adhesion decreases.

In the present invention, the compounding amount of the component (A) is 5 per 100 parts by weight of the total amount of the components (A) and (B).
0 to 70 parts by weight, preferably 55 to 67 parts by weight.
When the amount of the component (A) exceeds 70 parts by weight, the curability of the photosensitive resin composition becomes insufficient, and the adhesion decreases.
If the amount is less than 50 parts by weight, the photocured product tends to be brittle, and the storage stability of the photosensitive element is reduced.

As the ethylenically unsaturated compound (B) used in the present invention, for example, α, β-
Compounds obtained by reacting unsaturated carboxylic acids (polyethylene glycol di (meth) acrylate (having 2 to 14 ethylene groups), trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Trimethylolpropaneethoxytri (meth) acrylate, trimethylolpropanepropoxytri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, polypropylene glycol di (meth) acrylate (number of propylene groups Are 2 to 14), dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc.), and α,
Compounds obtained by adding a β-unsaturated carboxylic acid (bisphenol A such as bisphenol A dioxyethylene di (meth) acrylate, bisphenol A trioxyethylene di (meth) acrylate, bisphenol A decaoxyethylene di (meth) acrylate) Polyoxyethylene di (meth) acrylate, trimethylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate, etc.),
Esterified product of polycarboxylic acid (such as phthalic anhydride) and a compound having a hydroxyl group and an ethylenically unsaturated group (such as β-hydroxyethyl (meth) acrylate), (meth)
Alkyl esters of acrylic acid (methyl (meth) acrylate, ethyl (meth) acrylate,
Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc.), urethane (meth)
Acrylates (a reaction product of tolylene diisocyanate and 2-hydroxyethyl (meth) acrylate, a reaction product of trimethylhexamethylene diisocyanate, cyclohexane dimethanol and 2-hydroxyethyl (meth) acrylate), and the like. . These may be used alone or in combination of two or more, and the combination is not particularly limited.

In the present invention, the compounding amount of the component (B) is 3 per 100 parts by weight of the total amount of the components (A) and (B).
0 to 50 parts by weight, preferably 33 to 45 parts by weight.
If the amount of the component (B) exceeds 50 parts by weight, the photocured product tends to become brittle, and the storage stability of the photosensitive element decreases. If the amount is less than 30 parts by weight, the curability of the photosensitive resin composition will be insufficient and the adhesion will be reduced, and the development time will be long.

As the photopolymerization initiator (C) used in the present invention, for example, aromatic ketones (benzophenone, N,
N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), N, N'-tetraethyl-4,
4'-diaminobenzophenone, 4-methoxy-4'-
Dimethylaminobenzophenone, 2-ethylanthraquinone, phenanthrenequinone, etc.), benzoin (benzoin ether such as benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether, methyl benzoin, ethyl benzoin, etc.), benzyl derivative (benzyl benzyl ketal, etc.), 2 , 4,5-triarylimidazole dimer (2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2-
(O-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2-
(O-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5
-Diphenylimidazole dimer, 2,4-bis (p-
Methoxyphenyl) -5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer Acridine derivative (9-phenylacridine,
1,7-bis (9,9'-acridinyl) heptane and the like), thioxanthone, diethylthioxanthone and the like. These may be used alone or in combination of two or more, and the combination is not particularly limited.

In the present invention, the compounding amount of the component (C) is 0.5 to 10 parts by weight, preferably 1.0 to 5.0 parts by weight based on 100 parts by weight of the total of the components (A) and (B). Department. When the amount of the component (C) exceeds 10 parts by weight,
The curability at the bottom of the photosensitive resin composition becomes insufficient and the adhesiveness is reduced. When the amount is less than 0.5 part by weight, the curing time is prolonged.

The plasticizer (D) used in the present invention includes polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and a block copolymer of polyethylene glycol and polypropylene glycol.
Known plasticizers such as polyalkylene glycol diacetate such as polyethylene glycol diacetate and polypropylene glycol diacetate can be used, and are selected in consideration of the compatibility with the film-imparting polymer and the ethylenically unsaturated compound.

In the present invention, the amount of component (D) is 1.0 to 10 parts by weight, preferably 1.5 to 8.0 parts by weight, per 100 parts by weight of the total of components (A) and (B). Department. When the amount of the component (D) exceeds 10 parts by weight,
The adhesiveness of the photosensitive resin composition decreases, and the film strength decreases. If the amount is less than 1.0 part by weight, the flexibility of the film decreases.

As the pigment or dye (E) used in the present invention, known pigments or dyes can be used, and particularly, the compatibility with the film-imparting polymer and the ethylenically unsaturated compound, the target hue, and the desired light transmittance are obtained. It is selected in consideration of.

In the present invention, the component (E) is incorporated in an amount of 0.01 to 3.0 parts by weight, preferably 0.05 to 2.0 parts by weight, per 100 parts by weight of the total of the components (A) and (B). 5
Parts by weight. When the amount of the component (E) exceeds 3.0 parts by weight, the light transmittance is reduced, the adhesion is reduced, and 0.01%.
If the amount is less than parts by weight, coloring becomes insufficient.

The photosensitive resin composition of the present invention contains a color former such as tribromomethylphenyl sulfone, leuco crystal violet, a stabilizer, an adhesion promoter, a perfume,
An additive such as an antifoaming agent may be added as needed.

In the photosensitive resin composition of the present invention, each of the above components is dissolved in a solvent for dissolving the components, for example, toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, chloroform, methylene chloride, By dissolving in dimethylformamide, methanol, ethanol or the like, a uniform solution can be obtained.

The photosensitive resin composition of the present invention can be used as a photosensitive element by coating it on a support and drying it.

As the support, a polymer film, for example, a film made of polyethylene terephthalate, polypropylene, polyethylene or the like is used. Among them, a polyethylene terephthalate film is preferable.

Since these polymer films must be removable from the photosensitive layer later, they must not have been subjected to a surface treatment or made of a material that cannot be removed. . Further, the thickness of these polymer films is preferably 5 to 20 μm, and 7 to 1 μm.
More preferably, it is 6 μm.

Two of these polymer films may be used, one of which may be laminated on both sides of the photosensitive layer as a support for the photosensitive layer and the other as a protective film for the photosensitive layer.

In producing a photoresist image using the photosensitive element of the present invention, if the above protective film is present, after removing the protective film, the photosensitive layer is pressed against a substrate while heating. It is laminated by doing. The surface to be laminated is usually a metal surface, but is not particularly limited.

The temperature of the thermocompression bonding of the photosensitive layer is not particularly limited, but is usually 90 to 130 ° C. The pressure of the thermocompression bonding of the photosensitive layer is not particularly limited, but is usually 3 to 5 kg.
/ Cm ² .

If the photosensitive layer is heated as described above, it is not necessary to pre-heat the substrate in advance, but it is also possible to pre-heat the substrate in order to further improve the lamination property.

The photosensitive layer thus completed is then imagewise exposed to active light using a negative or positive film. At this time, if the polymer film present on the photosensitive layer is transparent, it may be exposed as it is, and if it is opaque, it must be removed. In terms of protecting the photosensitive layer, the polymer film is transparent,
It is preferable to expose through the polymer film while the polymer film remains.

As the active light, a light generated from a known active light source, for example, a carbon arc, a mercury vapor arc, a xenon arc or the like is used. Since the sensitivity of the photopolymerization initiator contained in the photosensitive layer is usually maximum in the ultraviolet region, the active light source should be one that effectively emits ultraviolet light.

The photopolymerization initiator is sensitive to visible light,
For example, in the case of 9,10-phenanthrene quinone or the like, visible light is used as the active light, and as the light source, a photographic flood bulb, a sun lamp, or the like is used in addition to the above.

Next, after the exposure, if a polymer film or the like is present on the photosensitive layer, the polymer film is removed, and then, using an aqueous alkali solution, for example, spraying, rocking immersion, brushing, scrubbing, etc. The unexposed portion is removed by a known method and development is performed.

Examples of the base of the alkaline aqueous solution include alkali hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, lithium carbonate or bicarbonate, sodium carbonate or heavy carbonate. Carbonates, alkali carbonates such as potassium carbonate or bicarbonate, potassium phosphate, alkali metal phosphates such as sodium phosphate,
Alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate are used, and sodium carbonate is particularly preferable.

The pH of the aqueous alkali solution used for development is 9
To 11, and the temperature is adjusted according to the developability of the photosensitive layer.

A surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating the development, and the like may be mixed in the aqueous alkali solution.

Further, when manufacturing a printed wiring board,
The surface of the substrate exposed using the developed photoresist image as a mask is processed by a known method such as etching or plating. The photoresist image is then typically stripped with an aqueous solution that is more alkaline than the aqueous alkaline solution used for development. As this strongly alkaline aqueous solution,
For example, a 1 to 5% by weight aqueous sodium hydroxide solution is used.

[0040]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1, Comparative Examples 1 to 14 Synthesis of Film-Promoting Polymer (a) 104.4 g of a 3/2 solution (hereinafter referred to as solution II) by weight of methylcellosolve / toluene was placed in a 300 ml flask at 85 ° C. Warm up. After keeping the temperature at 85 ° C. for 30 minutes, a solution B obtained by dissolving 13.0 g of methacrylic acid, 57.3 g of methyl methacrylate, 29.7 g of ethyl acrylate, and 1.3 g of azobisisobutyronitrile in 11.4 g of the solution was dissolved for 4 hours. To cause a drop reaction in the flask. Thereafter, the temperature was kept for 2 hours, and 0.15 g of azobisisobutyronitrile was added to the solution # 3.
To the solution C dissolved in 4.2 g, the mixture was further kept for 5 hours, and then cooled to obtain a film-imparting polymer (a). The methacrylic acid copolymerization amount of the obtained film property imparting polymer (a) was 13% by weight, the weight average molecular weight was 50,000, and the dispersity was 2.4.

Synthesis of Film-Promoting Polymer (b) A solution B to which a dropping reaction was carried out for 4 hours was added with 8.0 g of methacrylic acid,
62.3 g of methyl methacrylate, ethyl acrylate 2
9.7 g and 1.3 g of azobisisobutyronitrile were dissolved in 11.4 g of the solution to obtain a film-imparting polymer (b) under the same method and under the same conditions. The methacrylic acid copolymerization amount of the obtained film property imparting polymer (b) was 8% by weight, the weight average molecular weight was 51,000, and the degree of dispersion was 2.3.

Synthesis of Film-Promoting Polymer (c) 18 g of methacrylic acid, 52.3 g of methyl methacrylate, 29.times.
7 g and 1.3 g of azobisisobutyronitrile in solution # 1
A film-imparting polymer (c) was obtained in the same manner and under the same conditions except that the polymer was dissolved in 1.4 g. The methacrylic acid copolymerization amount of the obtained film property imparting polymer (c) is
18% by weight, the weight average molecular weight was 49,000, and the degree of dispersion was 2.4.

Synthesis of Film-Promoting Polymer (d) The content of azobisisobutyronitrile in Solution B was 0.5
g, the content of azobisisobutyronitrile in Solution C was set at 0.
A film-imparting polymer (d) was obtained in the same manner and under the same conditions except that the amount was changed to 05 g. Methacrylic acid copolymerization amount of the obtained film property imparting polymer (d) was 13% by weight,
The weight average molecular weight was 82,000, and the degree of dispersion was 2.5.

Synthesis of Film-Promoting Polymer (e) The content of azobisisobutyronitrile in the solution B was 5.3.
g, the content of azobisisobutyronitrile in Solution C was set at 0.
A film-imparting polymer (e) was obtained in the same manner and under the same conditions except that the amount was changed to 5 g. The methacrylic acid copolymerization amount of the obtained film property imparting polymer (e) was 13% by weight, the weight average molecular weight was 25,000, and the degree of dispersion was 2.3.

Synthesis of Polymer (f) Having Film Property The azobisisobutyronitrile content in Solution B was set to 1.0 g and the azobisisobutyronitrile content in Solution C was set to 0.1 g at a synthesis temperature of 70 ° C. The same way, except that
Under the conditions, a film-imparting polymer (f) was obtained. The methacrylic acid copolymerization amount of the obtained film property imparting polymer (f) was 13% by weight, the weight average molecular weight was 51,000, and the dispersity was 1.7.

Synthesis of Film-Promoting Polymer (g) The synthesis temperature was 95 ° C., the azobisisobutyronitrile content in solution B was 1.6 g, and the azobisisobutyronitrile content in solution C was 0.20 g. A film imparting polymer (g) was obtained in the same manner and under the same conditions as described above. The methacrylic acid copolymerization amount of the obtained film property imparting polymer (g) was 13% by weight, and the weight average molecular weight was 50,000.
0 and the degree of dispersion was 3.3.

Preparation of photosensitive element and evaluation of properties A solution of the photosensitive resin composition having the composition (unit: parts by weight) shown in Table 1 was applied to a polyethylene terephthalate film (Lumirror (registered trademark) manufactured by Toray Industries, Inc.) having a thickness of 16 μm. After drying, coating and drying is performed so that the film thickness becomes 30 μm.
A photosensitive element was obtained by coating with a polyethylene film of μm. While peeling off the polyethylene film from the obtained photosensitive element, the photosensitive layer was polished with Scotch Bright (registered trademark) Bafrol (manufactured by Sumitomo 3M).
A test piece was obtained by continuously laminating the copper surface of the dried and washed copper-clad laminate using a Hitachi high-temperature laminator. Table 2 shows the lamination conditions.

[0049] An ultra-high pressure mercury lamp was applied to the test piece through a 21-step tablet and a close contact and resolution test pattern.
Exposure was performed at 40 mJ / cm ² . After standing for 10 minutes, the polyethylene terephthalate film is peeled off, 30 ° C., 1% by weight
The film was developed with a sodium carbonate aqueous solution for a minimum developing time of 2.0 × developing time, and the number of curing steps of the step tablet, the adhesiveness of the resist, and the resolution were read.

Further, a photosensitive element is laminated on a copper-clad laminate having a through-hole of 3.2 mmφ in the same manner as described above, and a colorless and transparent 175 μm PET film is interposed therebetween.
Exposure and development were performed in the same manner as described above. Then 2.0mm
A φ steel rod was pressed onto the film on the through hole (displacement speed 2 cm / min), and the film strength (rupture strength) and film elongation of the resist were measured.

Further, a photosensitive element is laminated on the copper-clad laminate in the same manner as described above, and a colorless and transparent 175 μm PET is formed.
Exposure development was performed through the film in the same manner as described above. Thereafter, a test was conducted in accordance with the method of JIS K5400 to evaluate the adhesiveness (cross cut property) of the resist.

The storage stability is as follows: the photosensitive element is wound around a φ84 mm paper tube at a length of 200 m,
It was left in an environment of 60% RH, and evaluated by the amount of resist exuding from the end of the roll after 120 days (resist fusion: ×, no resist fusion: ○).

The coloring property was determined by visually observing the contrast between the resist and copper after development, and was evaluated as good when the contrast was good and poor when the boundary between the copper and the resist was not clear due to insufficient contrast.

Table 3 shows the evaluation results.

[0055]

[Table 1] * 1 Polypropylene glycol diacrylate manufactured by Shin-Nakamura Chemical Co., Ltd.

[0056]

[Table 2]

[0057]

[Table 3] As is clear from Table 3, the photosensitive resin composition of the present invention and the photosensitive element using the same have particularly excellent adhesion, resolution, flexibility and film strength, and film elongation. .

[0058]

According to the present invention, as an etching resist or a plating resist used for manufacturing a printed wiring board, precision processing of metal, etc., a photosensitive material having particularly excellent adhesion, resolution, flexibility, film strength and film elongation. The photosensitive resin composition and the photosensitive element using the same were obtained.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05K 3/06 H05K 3/06 H 3/18 3/18 D // C08F 2/48 C08F 2/48 265/06 265/06 (72) Inventor Yoshitaka Minami 4-13-1, Higashicho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Chemical Co., Ltd. Yamazaki Plant

Claims (2)

[Claims] (A) (meth) acrylic acid 10 to 15
Weight-average molecular weight obtained by copolymerization of 85-90% by weight of a compound represented by the general formula [I] with a weight-average molecular weight of 30,000-70,000,
50 to 70 parts by weight of a film-imparting polymer having a number average molecular weight (dispersion degree) of 2.0 to 3.0; (In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 1 to 12 carbon atoms.) (B) 30 to 50 parts by weight of an ethylenically unsaturated compound (provided that the component (A) And the total amount of component (B) is 100 parts by weight.), (C) 0.5 to 10 parts by weight of photopolymerization initiator based on 100 parts by weight of total amount of components (A) and (B).
Parts by weight, 1.0 to 10 parts by weight of the plasticizer (D) based on 100 parts by weight of the total of the components (A) and (B), and (E) the pigment or dye as the components (A) and (B). A photosensitive resin composition comprising 0.01 to 3.0 parts by weight based on 100 parts by weight of the total amount of 2. A photosensitive element obtained by applying and drying the photosensitive resin composition according to claim 1 on a support.