JP2000241971A - Photopolymerizable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photopolymerizable composition extremely adaptable to a defect inspector and high in contrast after exposure and DFR using this composition. SOLUTION: The photopolymerizable composition contains (a) a linear polymer having carboxylic groups in an amount of 100-600 acid equivalents and a weight average molecular weight of 200,000-500,000 in an amount of 20-90 weight %, (b) a photopolymerizable unsaturated compound having at least 2 terminal ethylene groups in an amount of 3-60 weight %, (c) a photopolymerization initiator in an amount of 0.01-30 weight %, (d) at least one kind of compound selected from (i) a compound represented by general formula (I) and (ii) an azomethine dye compound in an amount of 0.01-10 weight %. In general formula (I), each of R1 and R2 is a hydrocarbon or trihalogenomethyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photopolymerizable composition and a photopolymerizable resin laminate, and more particularly to an alkali-developable photopolymerizable composition and a photopolymerizable resin laminate suitable for making a printed wiring board. About.

[0002]

2. Description of the Related Art Conventionally, a so-called dry film resist (hereinafter abbreviated as DFR) comprising a support layer and a photopolymerizable layer has been used as a resist for producing printed wiring.
DFR is generally prepared by laminating a photopolymerizable composition on a support film, and often further laminating a protective film on the composition. The photopolymer layer used here is generally of an alkali developing type using a weak alkaline aqueous solution as a developing solution.

In order to form a printed wiring board using a DFR, a protective film is first peeled off, and then a DFR is laminated on a substrate for forming a permanent circuit such as a copper-clad laminate using a laminator or the like, and a wiring pattern mask film is formed. And the like. Next, if necessary, the support film is peeled off, and the unpolymerized portion of the photopolymerizable composition is dissolved or dispersed and removed with a developer to form a cured resist image on the substrate.

Using the resist image thus formed as a mask, the metal surface of the substrate is etched or plated, and then the resist image is peeled off using an alkaline aqueous solution stronger than a developing solution. Etc. are formed. In particular, recently, a so-called tenting method of covering a through hole (through hole) with a cured film and thereafter etching the same has been frequently used because of simplicity of the process. For etching, cupric chloride, ferric chloride, a copper-ammonia complex solution or the like is used.

[0005] Recently, as the density of printed wiring boards increases, high resolution corresponding to fine lines is required. In addition, there is a tendency to increase productivity by introducing an inspection machine after exposure to find defects due to foreign matter or the like at an early stage of a production line. The judgment by the defect inspection machine after the exposure is performed by identifying the unexposed portion and the exposed portion. In order to fit this inspection machine, after the photosensitive layer is exposed,
It is required to have a very good contrast.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photopolymerizable composition having a post-exposure contrast which is extremely suitable for such an inspection machine, and a DFR using the same. .

[0007]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the present invention can be achieved by using a specific compound as a component of a photopolymerizable composition, and have completed the present invention. Was. That is, in the first invention of the present application, (a) the carboxyl group content is 100
A linear polymer having a weight average molecular weight of 20,000 to 500,000, 20 to 90% by weight, and (b) a photopolymerizable unsaturated compound having at least two terminal ethylene groups, 3 to 6
0% by weight, (c) a photopolymerization initiator, 0.01 to 30% by weight, (d) (i) a compound represented by the following general formula (I),
And (ii) an azomethine dye compound, which is a photopolymerizable composition containing at least one compound selected from the group consisting of 0.01 to 10% by weight.

[0008]

Embedded image

(Wherein, R1 and R2 represent a hydrocarbon group or a trihalogen-substituted methyl group) In the second invention of the present application, a layer comprising the photopolymerizable composition of the first invention is provided on a support. It is a photopolymerizable resin laminate.
Hereinafter, the present invention will be described in detail. (I) The compound of the general formula (I) used for the component (d) of the photopolymerizable composition of the present invention includes, for example, triazine PP manufactured by Nippon Sibelhaegna, Inc., wherein R1 and R2 are trichloromethyl groups. R1, R
There are compounds in which 2 is a tribromomethyl group. Also,
(Ii) Examples of the azomethine dye compound include:
C. I. Solvent Yellow-93, KA manufactured by Nippon Kayaku
There is YASET YELLOW GN, OPLUS YELLOW 140 manufactured by Orient Chemical.

At least one compound selected from the group consisting of (i) the compound represented by the general formula (I) and (ii) an azomethine dye compound is contained in the photopolymerizable composition of the present invention in an amount of 0.01 to 0.01%. To 10% by weight.
More preferably, it is contained in the range of 1 to 3% by weight. If this amount is less than 0.01% by weight, the effect on the contrast after exposure is not sufficient, and if this amount exceeds 10% by weight, the resolution becomes poor. The contrast after exposure was measured using a color difference meter (SZII- # 80 manufactured by Nippon Denshoku Industries Co., Ltd.).
The difference between the unexposed portion and the exposed portion measured by COLOR MEASURING SYSTEM was evaluated by ΔE. The higher the ΔE, the better the contrast after exposure. The value of ΔE is preferably 25 or more, and more preferably 30 or more.

The post-exposure defect inspection is performed to identify foreign matter such as dust from the exposed substrate laminated on the copper-clad laminate. In addition, although identification is possible even on a substrate after development, it is possible to find a defect at an early stage of a production line and improve productivity by identifying it at a stage after exposure. The amount of the carboxyl group contained in the linear polymer of the component (a) of the present invention is from 100 to 100 in terms of acid equivalent.
It must be 600, preferably 300-400. The carboxyl group in the linear polymer is necessary to give the DFR developability and releasability to an aqueous alkali solution. If the acid equivalent is less than 100, the compatibility with a coating solvent or another composition, for example, a photopolymerizable unsaturated compound (monomer) decreases, and if it exceeds 600, the developability and the releasability decrease.

The linear polymer of the present invention has a molecular weight of 2
５０500,000, preferably 30,000-250,000.
When the molecular weight of the linear polymer exceeds 500,000, the developability and the resolution deteriorate. When the molecular weight is less than 20,000, the protrusion of the photopolymerizable layer during storage becomes remarkable, which is not preferable. Here, the acid equivalent refers to the weight of a polymer having one equivalent of a carboxyl group therein.

The acid equivalent is measured by potentiometric titration. The molecular weight is determined by gel permeation chromatography (GPC) as a weight average molecular weight (in terms of polystyrene). The linear polymer used in the present invention can be obtained by copolymerizing one or more of the following two types of monomers. The first monomer is a carboxylic acid or acid anhydride having one polymerizable unsaturated group in the molecule. Such compounds include, for example, (meth) acrylic acid, fumaric acid,
Cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, maleic acid half ester and the like. In addition, the second monomer is non-acidic, has one polymerizable unsaturated group in the molecule, develops the photopolymerizable layer, resistance in the etching and plating steps, flexibility of the cured film, and the like. Are selected to retain the various properties of Such compounds include, for example,
Examples thereof include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Further, a vinyl compound having a phenyl group (eg, styrene) can also be used.

It is essential that the component (b) of the present invention contains a photopolymerizable unsaturated compound having at least two terminal ethylene groups. Examples of such photopolymerizable compounds include 1,6-hexanediol di (meth) acrylate, 1,4-cyclohexanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and polyethylene glycol di (meth) acrylate. A) acrylate, polyoxyalkylene glycol di (meth) acrylate such as polyoxyethylene polyoxypropylene glycol di (meth) acrylate, 2di (p-hydroxyphenyl) propane di (meth) acrylate, glycerol tri (meth) acrylate, tri Methylolpropane tri (meth) acrylate, polyoxypropyl trimethylol propane tri (meth) acrylate,
Polyoxyethyltrimethylolpropane triacrylate, dipentaerythritol penta (meth) acrylate, trimethylolpropane triglycidyl ether tri (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, 2,2-bis (4-methacryloxy) (Pentaethoxyphenyl) propane, and polyfunctional (meth) acrylates containing a urethane group. These photopolymerizable compounds may be used alone or in combination of two or more, and may be used in combination with a monofunctional monomer such as phenoxypolyethylene glycol, β-hydroxypropyl-β ′-(acryloyloxy) propyl phthalate. You can also.

The amount of the component (b) used is 3 to 6
0% by weight is preferable, and if it is less than 3% by weight, the sensitivity is not sufficient. If it exceeds 60% by weight, the photopolymerizable layer protrudes significantly during storage, which is not preferable. As the photopolymerization initiator of the component (c) used in the present invention, known initiators which are activated by various actinic rays, for example, ultraviolet rays and start polymerization are used.

Examples of such a photopolymerization initiator include 2-ethylanthraquinone, octaethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,
3-diphenylanthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-
Quinones such as dimethylanthraquinone and 3-chloro-2-methylanthraquinone, benzophenone, and Michler-
Aromatic ketones such as duketone [4,4'-bis (dimethylamino) benzophenone], 4,4'-bis (diethylamino) benzophenone, benzoin, benzoinethyl ether, benzoinphenylether, methylbenzoin, ethyl Benzoin ethers such as benzoin, benzyldimethylketal, benzyldiethylketal, biimidazole compounds such as 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, thioxanthones and alkylaminobenzoic acid A combination of ethylthioxanthone and ethyl dimethylaminobenzoate, a combination of 2-chlorothioxanthone and ethyl dimethylaminobenzoate, a combination of isopropylthioxanthone and ethyl dimethylaminobenzoate,
Combination of (ο-chlorophenyl) -4,5-diphenylimidazolyl dimer with Michler's ketone, acridines such as 9-phenylacridine, 1-phenyl-1,2-propanedione-2-ο-benzoyloxime, 1-phenyl- 1,2-propanedione-2- (ο
Oxime esters such as (ethoxycarbonyl) oxime.

Preferred examples of these initiators include thioxanthones such as diethylthioxanthone and chlorothioxanthone, dialkylaminobenzoic esters such as ethyl dimethylaminobenzoate, benzophenone,
4,4'-bis (dimethylamino) benzophenone,
4,4'-bis (diethylamino) benzophenone, 2
-(O-chlorophenyl) -4,5 diphenylimidazolyl dimer, and combinations thereof.

Particularly, when higher resolution is required,
4′-bis (dimethylamino) benzophenone or 4,4′-bis (diethylamino) benzophenone and 2
A combination of-(o-chlorophenyl) -4,5 diphenylimidazolyl dimer is effective. In order to improve the thermal stability and storage stability of the photopolymerizable composition of the present invention, it is preferable that the photopolymerizable composition contains a radical polymerization inhibitor.

Such radical polymerization inhibitors include:
For example, p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, tert-butylcatechol cuprous chloride, 2,6-di-tert-butyl-p-
Cresol, 2,2'-methylenebis (4-ethyl-6
-Tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol-
), Aluminum nitrosophenylhydroxyamine, diphenylnitrosamine and the like.

The photopolymerizable composition of the present invention may contain coloring substances such as dyes and pigments. Such coloring substances include, for example, fuchsin, phthalocyanine green, olamine base, alkoxide green S, paramagenta, crystal violet, methyl orange, Nile Bull-2B, Victoria Bull, malachite green, and Basic Bull. -20, diamond grease-
And the like.

Further, the photopolymerizable composition of the present invention may contain a coloring dye which develops a color upon irradiation with light. Examples of such a coloring dye include a combination of a leuco dye or a fluoran dye and a halogen compound. As the leuco dye, for example, tris (4-dimethylamino-2-methylphenyl) methane [leuco crystal violet], tris (4-dimethylamino-2)
-Methylphenyl) methane [leucomalachite gly-
And the like. On the other hand, as a halogen compound, amyl bromide, isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzal bromide, methylene bromide, tribromomethylphenylsulfone, carbon tetrabromide, tris (2, 3-dibromopropyl) phospho-
, Trichloroacetamide, amyl iodide, isobutyl iodide, 1,1,1-trichloro-2,2-bis (p
-Chlorophenyl) ethane, hexachloroethane and the like. Among such coloring dyes, a combination of tribromomethylphenylsulfone and a leuco dye is useful.

If necessary, the photopolymerizable composition of the present invention may contain an additive such as a plasticizer. When the photopolymerizable resin laminate (second invention) of the present invention is used,
The photopolymerizable resin composition is applied on a support layer. As a material for such a support layer, a transparent material that transmits active light is desirable. Examples of the material for such a support layer include a polyethylene terephthalate film, a polyvinyl alcohol film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyvinylidene chloride film, a vinylidene chloride copolymer film, and a polymethyl methacrylate copolymer film. , A polystyrene film, a polyacrylonitrile film, a styrene copolymer film, a polyamide film, a cellulose derivative film, and the like. These films may be stretched if necessary. A thinner thickness is advantageous in terms of image formability and economy, but 10 to 30 μm is necessary to maintain strength.
m is common.

A protective layer is laminated on the surface opposite to the photopolymerizable layer laminated with the support layer, if necessary. It is an important characteristic of the protective layer that the protective layer has a sufficiently small adhesive force with the photopolymerizable layer and can be easily peeled off than the support layer. Examples of such a protective layer include a polyethylene film and a polypropylene film. Although the thickness of the photopolymerizable layer varies depending on the application, it is 5 to 100 μm for production of a printed wiring board, preferably 5 to 90 μm.
m, and the resolving power improves as the photopolymerization layer becomes thinner. Further, as the photopolymerizable layer is thicker, the film strength is improved.

The process of producing a printed wiring board using the photopolymerizable resin laminate is performed by a known technique, and the process will be briefly described below. If there is a protective layer, the protective layer is first peeled off, and then the photopolymerizable layer is laminated on the metal surface of the printed wiring board substrate by heating and pressing. The heating temperature at this time is generally 40 to 160 ° C. Next, if necessary, the support layer is peeled off, and image exposure is performed with actinic light through a mask film. Next, if there is a support layer on the photopolymerizable layer, the support layer is removed if necessary, and then the unexposed portion of the photopolymerizable layer is developed and removed using an alkaline aqueous solution. As the alkaline aqueous solution used here, an aqueous solution of sodium carbonate, potassium carbonate or the like is used. These alkaline aqueous solutions are selected in accordance with the characteristics of the photopolymerizable layer, but are generally selected from the group consisting of 0.1 to 0.1%.
A 5 to 3% aqueous sodium carbonate solution is used.

Next, an image pattern of a metal is formed on the metal surface exposed by the development by using a known etching method or a plating method. Thereafter, the cured resist image is peeled off with an aqueous alkaline solution which is generally stronger than the aqueous alkaline solution used for development. There is no particular limitation on the alkaline aqueous solution for stripping, but 1% to 5%.
% Aqueous solutions of sodium hydroxide and potassium hydroxide are commonly used. It is also possible to add a small amount of a water-soluble organic solvent to a developer or a stripper.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to examples.

[0027]

Example 1 A compound having the composition shown in Table 1 (column of Example 1) was uniformly dissolved. Next, this mixed solution is applied to a thickness of
m of polyethylene terephthalate film using a bar coater and dried in a drier at 95 ° C. for 3 minutes. At this time, the thickness of the photopolymerizable layer was 30 μm. A 25 μm polyethylene film was laminated on the surface of the photopolymerizable layer on which the polyethylene terephthalate film was not laminated to obtain a laminated film. On the other hand, 35μ
Wet buffling polishing of the surface of a copper-clad laminate obtained by laminating m-rolled copper foil (Scotch Bright # 60 manufactured by 3M)
0 or 2), and the photopolymerizable layer was laminated at 105 ° C. using a hot roll laminator while peeling off the polyethylene film of the laminated film. An ultra-high pressure mercury lamp (Oak Works H
(MW-201KB) to expose the photopolymerizable layer at 80 mJ / cm ² . Subsequently, after peeling off the polyethylene terephthalate support film, a 1% aqueous solution of sodium carbonate at 30 ° C. was sprayed for about 35 seconds to dissolve and remove the unexposed portions, whereby a good cured image was obtained.

The following evaluation was performed on the laminate using the photopolymerizable composition of the present invention. (1) Measurement of minimum development time While peeling off the polyethylene film of the dry film resist on a copper-clad laminate laminated with 35 μm rolled copper foil, the photopolymerizable layer was heated at 105 ° C. by a hot roll laminator.
Was laminated. Subsequently, after the polyethylene terephthalate support film of the laminate was peeled off, it was heated at 30 ° C.
% Sodium carbonate aqueous solution was sprayed, the minimum development time at which the unexposed photopolymerizable layer was dissolved was measured, and this time was defined as the minimum development time. Actual development is the minimum development time of 1.
This was performed five times as long. (2) Resolution 80 m by an ultra-high pressure mercury lamp (Oak Seisakusho HMW-201KB) through a mask film having a line and space of 1: 1 on the laminate laminated on the copper-clad laminate.
Exposure was at J / cm ² . Subsequently, after peeling off the polyethylene terephthalate support film, a 1% aqueous solution of sodium carbonate at 30 ° C. was sprayed for about 35 seconds. The minimum line width of the obtained image that can be separated was defined as the resolution. (3) Exposure contrast 80 mJ was applied to the laminate laminated on the copper-clad laminate using an ultra-high pressure mercury lamp (Oak Seisakusho HMW-201KB).
/ Cm ² . Immediately thereafter, a color difference meter (SZII- @ 80 COLOR MEASURIN manufactured by Nippon Denshoku Industries Co., Ltd.) was used.
G System), the Lab of the unexposed part and the Lab of the exposed part were measured, and the difference ΔE was measured. (4) Defect inspection after exposure As a defect inspection machine after exposure, FPT-fast85 manufactured by Yachiyoko Corporation was used.

[0029]

Examples 2 to 6 and Comparative Examples 1 to 5 Photopolymerizable resin laminates having the compositions shown in Table 1 were obtained in the same manner as in Example 1, and the minimum development time was measured, and the resolution and the exposure contrast were evaluated. went. Table 1 shows the results. As you can see from this table,
When using the photopolymerizable resin laminate of Comparative Examples 1 to 5,
ΔE was as low as less than 20, and the compatibility with the inspection machine after exposure was poor. On the other hand, when the photopolymerizable resin laminates of Examples 1 to 6 were used, ΔE was all 30 or more, and the compatibility with the inspection machine after exposure was good.

<Symbol description> P-1: A ternary copolymer of methyl methacrylate 70% by weight, methacrylic acid 23% by weight, and butyl acrylate 7% by weight in methyl ethyl ketone (solid content 30%, weight average molecular weight 12) 10,000) P-2: Methyl tyl ketone solution of a terpolymer of 47% by weight of methyl methacrylate, 23% by weight of methacrylic acid and 30% by weight of styrene (solid content: 32%, weight average molecular weight: 45,000) M -1: trimethylolpropane triacrylate M-2: tetraethylene glycol dimethacrylate M-3: nanoethylene glycol diacrylate M-4: β-hydroxypropyl-β ′-(acryloyloxy) propyl phthalate M-5: average Ethylene oxide is added to polypropylene glycol to which 8 mol of propylene oxide has been added. Glycol dimethacrylate added to both ends on average of 3 moles each M-6: Bisphenol A was added to both ends of polypropylene glycol having an average of 3 moles of propylene oxide added to both ends and an average of 5 moles of ethylene oxide were added. Dimethacrylate of polyethylene glycol A-1: benzophenone A-2: 4,4'-bis (dimethylamino) benzophenone A-3: 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer B -1: diamond green B-2: leuco crystal violet X-1: 2,4-trichloromethyl (piperonyl) -6
-Triazine (Triazine P manufactured by Nippon Sebel Hegner Co.)
P) X-2: KAYASET YELLOW GN (Nippon Kayaku Co., Ltd.)

[0031]

[Table 1]

[0032]

EFFECT OF THE INVENTION D using the photopolymerizable resin composition of the present invention
When FR is used for the manufacture of printed wiring boards, it exhibits extremely good contrast after exposure, so that the suitability for an inspection machine after exposure is good, and the productivity can be extremely high. Further, the DFR of the present invention has a high resolution corresponding to fine line formation, and is very useful as an alkali development type DFR for manufacturing a printed wiring board.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AA00 AA02 AA04 AB11 AB15 AC01 AD01 BC12 BC14 BC42 BC43 BC82 CA00 CA03 CA14 CA28 CB43 CB55 CC13 CC20 FA17 5E339 BC02 BD03 BD06 BD11 CC01 CC02 CC10 CD01 CE16 CF16 CF17 DD02 FF10

Claims (2)

[Claims] 1. (a) The carboxyl group content is from 100 to 600 in acid equivalent and the weight average molecular weight is from 20,000 to 5
10,000 linear polymers, 20-90% by weight, (b) a photopolymerizable unsaturated compound having at least two terminal ethylene groups,
3 to 60% by weight, (c) photopolymerization initiator, 0.01 to 30
% By weight, at least one compound selected from the group consisting of (d) (i) a compound represented by the following general formula (I), and (ii) an azomethine dye compound;
A photopolymerizable composition containing about 10% by weight. Embedded image (Wherein, R1 and R2 represent a hydrocarbon group or a trihalogen-substituted methyl group) 2. A photopolymerizable resin laminate comprising a support and a layer comprising the photopolymerizable composition according to claim 1 provided on a support.