JPH08157744A - Photosensitive resin composition and photosensitive element produced therefrom - Google Patents

Abstract

PURPOSE: To obtain a photosensitive resin compsn. which has high photosensitivity, does not widen resist lines, and hardly stains a plating soln. because the soln. hardly dissolves a photoinitiator, and to provide a photosensitive element produced from the compsn. CONSTITUTION: This resin compsn. contains 40-80 pts.wt. carboxylated polymer, 20-60 pts.wt. polymerizable compd. having at least one unsatd. bond (the sum of the polymer and the compd. being 100 pts.wt.), 0.05-1 pt.wt. photoinitiator represented by the formula (wherein R<1> is a 6-12C alkylene), and 0.1-3.0 pts.wt. hexaarylbiimidazole. A photosensitive element is produced by forming a layer of the compsn. on a substrate film.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photosensitive resin composition and a photosensitive element using the same.

[0002]

2. Description of the Related Art Conventionally, photosensitive resin compositions and photosensitive films have been widely used as resist materials used for etching, plating and the like in the fields of manufacturing printed wiring boards and precision processing of metals. In addition, as a method of manufacturing a printed wiring board, the plating method is becoming the mainstream because the density of the printed wiring board has been increasing and the pattern has been thinned in recent years.

In this plating method, the resist is covered except for the through holes and the electric circuits for mounting the chips, the through holes and the electric circuits are formed by electroplating, and then the electric circuits are prepared by removing the resist and etching. Is the way to do it. As the plating solution in the plating method, copper pyrophosphate, copper sulfate, solder, nickel, palladium, gold, etc. are used, but it is common to use copper sulfate for the production of electric circuits and use solder for its protection. is there.

During these platings, depending on the type of photoinitiator that dissolves from the photosensitive resin composition and the photosensitive element into the plating solution, the copper sulfate plating may not be sufficiently deposited, or the solder plating of the protective layer may be difficult. It is known that the tin / lead ratio deviates greatly from the target ratio. Due to this deviation of the alloy ratio, problems such as solder melting at the time of resist stripping and line thinning of the underlying copper during etching occur.

The photosensitive resin composition and the photosensitive element used in the conventional plating method are contained in the photosensitive resin composition in order to reduce the amount of the photoinitiator eluted into the plating solution. The light sensitivity was low.

To improve these problems, Japanese Patent Publication No.
-29285 discloses hexaarylimidazole and the following general formula (II)

Embedded image (Wherein R ² and R ³ represent an alkyl group, n is 1, 2 or 3, and ring A represents a nitrogen-containing aromatic ring), it is proposed to use a compound represented by There arises a problem that the pattern width of the subsequent resist becomes thick and the circuit width formed by plating becomes thin. Also, if the exposure amount is reduced,
Although the line width becomes narrower, the problem of plating chipping occurs due to insufficient curing.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, the resist line width is not thick, the photosensitivity is high, and the photoinitiator is hardly eluted into the plating solution. Therefore, the present invention provides a photosensitive resin composition and a photosensitive element in which the plating solution is less contaminated.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a polymerizable compound (A) 40 to 80 parts by weight of a polymer having a carboxyl group, and (B) a polymerizable compound 2 having at least one unsaturated bond.
0 to 60 parts by weight (so that the total amount of (A) and (B) is 100 parts by weight), (C) general formula (I)

Embedded image (Wherein R ¹ represents an alkylene group having 6 to 12 carbon atoms) in an amount of 0.05 to 1 part by weight (as described above).
(Based on 100 parts by weight of (A) and (B)) and (D)
A photosensitive resin composition containing 0.1 to 3.0 parts by weight of hexaarylbiimidazole (based on the total amount of 100 parts by weight of (A) and (B)) and the above-mentioned photosensitive material on a support film. The present invention relates to a photosensitive element formed by laminating layers of a resin composition.

Next, the components contained in the photosensitive resin composition of the present invention will be described in detail. Examples of the polymer having a carboxyl group used as the component (A) in the present invention include (meth) acrylic acid alkyl ester [(meth) acrylic acid means methacrylic acid and acrylic acid.
The same shall apply hereinafter] and a copolymer of (meth) acrylic acid and a vinyl monomer copolymerizable therewith, and the like. These copolymers are used alone or in combination of two or more.

Examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester,
(Meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) acrylic acid 2-ethylhexyl ester and the like can be mentioned. Examples of vinyl monomers copolymerizable with (meth) acrylic acid alkyl ester and (meth) acrylic acid include (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) Acrylic acid diethylaminoethyl ester, methacrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth)
Acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate acrylamide, diacetone acrylamide, styrene, vinyltoluene and the like can be mentioned.

The polymerizable compound having at least one unsaturated bond used as the component (B) in the present invention is, for example, a polyhydric alcohol (polyethylene glycol di (meth) acrylate (having a number of ethylene groups). 2-14
), Trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethoxytri (meth) acrylate, trimethylolpropane propoxytri (meth) acrylate, tetramethylolmethane tri (meth) acrylate , Tetramethylolmethane tetra (meth) acrylate, polypropylene glycol di (meth) acrylate (having 2 to 14 propylene groups), dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Compounds obtained by reacting α, β-unsaturated carboxylic acids, glycidyl group-containing compounds (bisphenol A dioxyethylene di (meth) acrylate, bisphenol A trioxyethylene (Meth) acrylate,
Bisphenol A decaoxyethylene di (meth) acrylate and other bisphenol A dioxyethylene di (meth) acrylate, trimethylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether acrylate, etc.) and α, β-unsaturated carboxylic acid , A compound obtained by adding a polycarboxylic acid (phthalic anhydride, etc.) and an esterified product of a substance having a hydroxyl group and an ethylenically unsaturated group (β-hydroxyethyl (meth) acrylate, etc.), (meth) acrylic acid Alkyl ester ((meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) acrylic acid 2-ethylhexyl ester, etc.), urethane (meth) acrylate (tolylene diisocyanate and - hydroxyethyl (meth) reaction product of an acrylic acid ester, trimethylhexamethylene diisocyanate and cyclohexanedimethanol and 2
-Hydroxyethyl (meth) acrylic acid ester and the like) and the like.

The compounding amount of the component (A) in the present invention is 4
0 to 80 parts by weight (total amount of component (A) and component (B) is 100)
It should be set to be 5 parts by weight). If the blending amount is less than 40 parts by weight, the photocured product becomes brittle and the coating property is poor when used as a photosensitive film. Further, if the blending amount exceeds 80 parts by weight, sufficient sensitivity cannot be obtained.

The blending amount of the component (B) in the present invention is 20 to 60 parts by weight (so that the total amount of the components (A) and (B) is 100 parts by weight). It is preferably 45 parts by weight. If this amount is less than 20 parts by weight, sufficient sensitivity cannot be obtained, and if it exceeds 60 parts by weight, the photocured product becomes brittle.

Further, as the component (B), it is preferable to use a compound having two or more unsaturated bonds from the viewpoint of improving the sensitivity.

The general formula (I) used as the component (C) in the present invention

[Chemical 4] Examples of the photoinitiator represented by (wherein R ¹ represents an alkylene group having 6 to 12 carbon atoms) include 1,6-bis (9-acridinyl) hexane and 1,7-bis (9 −
Acridinyl) heptane, 1,8-bis (9-acridinyl) octane, 1,9-bis (9-acridinyl) nonane, 1,10-bis (9-acridinyl) decane,
1,11-bis (9-acridinyl) undecane, 1,
12-bis (9-acridinyl) dodecane and the like can be mentioned.

The photoinitiator (acridine compound) represented by the general formula (I) which is the component (C) can be easily prepared by reacting diphenylamine and a divalent carboxylic acid in the presence of a metal oxide. It can be manufactured.

The blending amount of the component (C) in the present invention is
The amount is 0.05 to 1 part by weight (relative to 100 parts by weight of the total amount of the components (A) and (B)), and preferably 0.1 to 0.5 parts by weight. If the content is less than 0.05 parts by weight, sufficient photosensitivity cannot be obtained, and if it exceeds 1 part by weight, the sensitivity is not further improved and the amount of dissolution in the plating bath increases, resulting in contamination of the plating bath. Becomes noticeable.

Examples of the hexaarylbiimidazole used as the component (D) in the present invention include:
2,2'-bis (o-chlorophenyl) -4,4 ',
5,5'-tetraphenylbiimidazole, 2,2'-
Bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p
-Dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole , 2,2'-bis (o, o '
-Dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2 ′ -Bis (o-methylphenyl)-
4,4 ', 5,5'-tetraphenylbiimidazole and the like can be mentioned. These hexaarylbiimidazoles, for example, Bull.Chem.Soc.Japan, 33, 565 (1960 ), J.or
It can be easily synthesized by the method disclosed in g. Chem., 36 [16] 2262 (1971) and the like.

The blending amount of the component (D) in the present invention is
0.1 to 3.0 parts by weight (based on 100 parts by weight of the total amount of the components (A) and (B)), and preferably 0.5 to 2.5 parts by weight. If the blending amount is less than 0.1 parts by weight, sufficient photosensitivity cannot be obtained, and if it exceeds 3.0 parts by weight, the resist line width becomes thick.

The photosensitive resin composition of the present invention contains a vinyl compound other than the above, a photoinitiator, a plasticizer, a dye, if necessary.
A pigment, an imaging agent, a filler, an adhesion-imparting agent, etc. can be blended and used.

The photosensitive resin composition of the present invention is applied on a metal surface, for example, a surface of copper, nickel, chromium or the like, preferably a copper surface, as a liquid resist and dried, and then coated with a protective film. Or used as a photosensitive element. The thickness of the photosensitive resin composition layer varies depending on the application, but it is preferably 10 to 100 μm after drying. In the case of a liquid resist, an inert polyolefin film such as polyethylene or polypropylene is used as the protective film.

The photosensitive element can be obtained by applying a photosensitive resin composition on a support film such as polyester and drying the composition, and optionally laminating a protective film such as polyolefin. The photosensitive resin composition is mixed with a solvent such as acetone, methyl ethyl ketone, methylene chloride, toluene, methanol, ethanol, propanol, butanol, methyl glycol, ethyl glycol, propylene glycol, monomethyl ether, or a mixed solvent thereof, if necessary. It may be applied as a solution.

The above-mentioned photosensitive resin composition layer is irradiated with actinic rays in a pattern through a negative or positive mask pattern called artwork, and then developed with a developing solution,
It is used as a resist pattern. As the active light source used at this time, for example, a carbon arc lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a xenon lamp or the like that effectively radiates ultraviolet rays is used.

As the developing solution, a developing solution which is safe and stable and has good operability is used, and a dilute solution of sodium carbonate or the like is used for an alkali developing type photoresist. Development methods include a dip method and a spray method, and the high pressure spray method is most suitable for improving the resolution.

Electroplating performed after development includes copper plating (copper sulfate plating, copper pyrophosphate plating, etc.), solder plating (high-throw solder plating, etc.), Watts bath (nickel sulfate-nickel chloride) plating, nickel plating (sulfamine). Nickel acid plating, etc.), gold plating (hard gold plating, soft gold plating, etc.).

[0026]

EXAMPLES The present invention will now be described with reference to examples. Examples 1-2 and Comparative Examples 1-3 The materials shown in Table 1 and Table 2 were blended to obtain solutions.

[Table 1]

[Table 2]

The components (C) and (D) shown in Table 3 were dissolved in this solution to obtain a solution of a photosensitive resin composition.

[Table 3]

Then, a solution of this photosensitive resin composition is added to 2
It was uniformly coated on a polyethylene terephthalate film having a thickness of 5 μm, and dried for 10 minutes by a hot air convection dryer at 100 ° C. to obtain a photosensitive element. The film thickness of the photosensitive resin composition layer after drying was 50 μm. On the other hand, a copper-clad laminate which is a glass epoxy material in which copper foil (thickness 35 μm) is laminated on both sides (manufactured by Hitachi Chemical Co., Ltd., trade name MCL-E-6)
The copper surface of 1) was polished using a polishing machine (manufactured by Sankei Co., Ltd.) having a brush equivalent to # 600, washed with water, and dried with an air stream, and the obtained copper-clad laminate was heated to 80 ° C. Then, the photosensitive resin composition layer was laminated on the copper surface while heating at 120 ° C.

Then, on the substrate thus obtained,
Using a negative film, exposure was performed at 60 mJ / cm ² with a 3 kW high pressure mercury lamp (HMW-201B, manufactured by Oak Manufacturing Co., Ltd.). At this time, in order to evaluate the photosensitivity and the line width, a negative film (optical density 0.05 is set as the first step and the optical density is set to 0. A 21-step tablet increasing in 15 steps was used. Regarding the line width, the exposure amount showing 8 steps with a 21-step tablet is line / space = 100 μm.
It was exposed using a negative film of / 100 μm.

Then, the polyethylene terephthalate film was removed, and an unexposed portion was developed by spraying a 1% by weight aqueous sodium carbonate solution at 30 ° C. for 50 to 150 seconds to form a photo-cured film formed on the copper-clad laminate. The photosensitivity of the photosensitive resin composition was evaluated by measuring the number of steps of the step tablet. The results are shown in Table 4. The light sensitivity is indicated by the number of steps of the step tablet, and the higher the number of steps of this step tablet, the higher the light sensitivity. The line width indicates the difference from the pattern width of the negative film. The larger the plus side, the thicker the resist line width.

Next, using a separately prepared photosensitive element, each element was exposed using a 21-step step tablet at an exposure amount showing a value of 8 steps, and then the polyethylene film and the polyethylene terephthalate film were removed and exposed to light. A cured photosensitive resin composition layer (cured film) was obtained. Then, the cured film is treated with a solder plating solution [45 wt%
Tin borofluoride 64 ml / liter, 45% by weight lead borofluoride 2
2 ml / liter, 42 wt% borohydrofluoric acid 200 ml / liter, Plutein LA Conductivity Salt (Meltex, trade name) 20 g / L, Plutein LA Starter (Meltex, trade name) 40 ml / L] 0 It was immersed at a rate of 1 m ² / liter. After leaving the film-cured product immersed at room temperature for 7 days, the solder plating solution from which the film-cured product had been removed was put into a Hull cell plating apparatus, and plating was performed at 1 A for 5 minutes in the same apparatus.

After plating, a current density of 3 was obtained using a fluorescent X-ray film thickness meter (manufactured by Seiko Denshi KK, trade name STF-158V).
The tin / lead ratio (A ₁ ) of the plating film at the A / dm ² portion was measured. At that time, the tin / lead ratio (A ₂ ) of the product in which the cured film was not dipped was used as a blank, and A ₁ / A ₂ was used as the alloy ratio. The closer this value is to 1, the less the contamination of the plating bath.

[0033]

[Table 4]

From Table 4, it was confirmed that in Examples 1 and 2 in which the components (C) and (D) were blended in a predetermined amount, the resist line width was not thick and the photosensitivity was high, and there was almost no plating bath contamination. Was done.

[0035]

EFFECT OF THE INVENTION The photosensitive resin composition of the present invention and the photosensitive element using the same are excellent in that the resist line width is not thick, there is almost no plating bath contamination, and the photosensitivity is high.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location G03F 7/031 H05K 3/06 H N2-3 (72) Inventor Yuichi Kamakura 4 Higashimachi, Hitachi City, Ibaraki Prefecture No. 13-1 Hitachi Chemical Co., Ltd. Yamazaki Factory

Claims (2)

[Claims] 1. (A) 40 to 80 parts by weight of a polymer having a carboxyl group, (B) 20 to 60 parts by weight of a polymerizable compound having at least one unsaturated bond ((A) and
(The total amount with (B) is 100 parts by weight),
(C) General formula (I) (Wherein R ¹ represents an alkylene group having 6 to 12 carbon atoms) in an amount of 0.05 to 1 part by weight (as described above).
(Based on 100 parts by weight of (A) and (B)) and (D)
A photosensitive resin composition containing 0.1 to 3.0 parts by weight of hexaarylbiimidazole (based on 100 parts by weight of the total of (A) and (B)). 2. A photosensitive element formed by laminating a layer of the photosensitive resin composition according to claim 1 on a support film.