JPH1172914A - Photo-polymerizable resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a photo-polymerizable resin composition improved in flexibility without impairing pattern forming performance as liquid etching resist. SOLUTION: This photo-polymerizable resin composition consists, essentially of, (A) (meth)acrylic-copolymer having a weight average molecular weight, expressed in terms of polystyrene of 3,000-20,000, an unsaturated equivalent of 0-2.0 meq/g, and carboxylic acid with an acid value of 0.5-3.0 meq/g, (B) (meth)acrylate, (C) an organic polyvalent amine compound, and (D) a photo- initiator, wherein 1-90% of the carboxylic acid in the component (A) is neutralized with amine of the component (C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention provides a photopolymerizable resin composition particularly suitable as a liquid photo-etching resist used in a process for producing a printed wiring board.

[0002]

2. Description of the Related Art Conventionally, as an etching resist in a manufacturing process of a printed wiring board, a screen ink,
Dry film resists, electrodeposition resists and the like are used. Among these, in particular, a resist material that can meet the demand for higher density in a printed wiring board is an electrodeposition resist that is excellent in forming fine patterns. However, the electrodeposition resist has not been widely used because bath management is complicated and initial equipment investment is large.

On the other hand, liquid photoresists have recently been receiving attention. Liquid photoresists can reduce the thickness of a resist coating film as compared with an electrodeposited resist as compared with a dry film resist, and therefore can be expected to have a fine patterning property equal to or higher than that of an electrodeposited resist. Further, bath management like an electrodeposition resist is not required, and it can be made cheaper than an electrodeposition resist from the viewpoint of capital investment, so that it is promising as a fine pattern forming method in the future.

On the other hand, besides such fine pattern forming property (resolution), an important property required for a liquid resist is flexibility of a coating film. If the flexibility of the coating film is insufficient,
Chipping is likely to occur in the developed resist pattern, which results in a reduction in the yield in substrate manufacturing. Considering the actual process, when a physical force is applied by a transport roll or the like in the substrate transport process, or when the spray pressure is applied to the resist coating portion protruding by side etching in the etching process, the coating is chipped. Tends to occur.

[0005]

On the other hand, as a method of increasing the flexibility of the coating film, it is conceivable to increase the molecular weight of the base polymer by blending a flexible component. However, in the former method, flexibility is improved, but other physical properties are often adversely affected, and it is particularly difficult to balance with developability and resolution. On the other hand, the latter method is very effective as a means for improving flexibility, but it is also difficult to achieve a balance in physical properties because the resolution is lowered with an increase in molecular weight.

On the other hand, the present inventors have proposed a method for improving the flexibility of a coating film without adversely affecting other physical properties. In particular, increasing the molecular weight of the base polymer is very effective in improving the flexibility. Focusing on this point, we conducted intensive studies.

As a result, a pseudo-crosslinking reaction is caused via the organic polyamine compound by utilizing a neutralization reaction between a carboxyl group contained in the base polymer and an amino group of the organic polyamine compound, and apparently. It has been found that the flexibility is improved by increasing the molecular weight of. Moreover, this reaction is reversible, and the crosslinking is easily released in a developing solution which is a weak alkaline aqueous solution, so that the developing process is not adversely affected. They have found that the performance can be expressed as it is, and have completed the present invention.

[0008]

The present invention provides: A) a polystyrene equivalent weight average molecular weight of 3,000 to
20,000, an unsaturated equivalent of 0 to 2.0 meq / g (solid matter conversion, the same applies hereinafter), and an acid value of 0.5 to 3.0 m
B) acrylate / carboxy group-containing acrylic copolymer and / or methacrylic copolymer (hereinafter referred to as “(meth) acrylic copolymer”) which is eq / g (in terms of solid component). And / or methacrylate (hereinafter referred to as “(meth) acrylate”); C) an organic polyvalent amine compound; D) a photopolymerization initiator; and 1 to 9 carboxyl groups in component A).
A photopolymerizable resin composition characterized in that 0% is neutralized by the component (C).

[0009]

DETAILED DESCRIPTION OF THE INVENTION The carboxyl group-containing (meth) acrylic copolymer used in the present invention has a polystyrene equivalent weight average molecular weight of 3,000 to 20,000 and an unsaturated equivalent of 0 to 2.0 meq. / G, and an acid value of 0.5 to
3.0 meq / g. If the weight average molecular weight in terms of polystyrene is less than 3,000, the resist coating film obtained by photopolymerizing the photopolymerizable resin composition of the present invention becomes insufficiently resistant to an etching solution, and if it exceeds 20,000. This has an adverse effect on the fine pattern formation, and the scum of the pattern after development becomes remarkable. In order to obtain a carboxyl group-containing (meth) acrylic copolymer having a desired molecular weight, a chain transfer agent such as dodecyl mercaptan or mercaptopropionic acid may be appropriately used in the polymerization reaction.

The carboxyl group-containing (meth) acrylic copolymer does not necessarily have to have a polymerizable unsaturated bond, but it is possible to introduce a polymerizable unsaturated bond by an appropriate method if desired. You may. However, if the unsaturated equivalent exceeds 2.0 meq / g, the stripping properties of the resist are adversely affected, and the stripping time becomes extremely long.

The introduction of the unsaturated bond into the carboxyl group-containing (meth) acrylic copolymer can be carried out by various methods using the following reactions. Utilizing the reaction between carboxylic acid and epoxy, for example, adding a glycidyl group-containing unsaturated compound to a carboxyl group in the copolymer, or adding an unsaturated carboxylic acid to an epoxy group in the copolymer. Utilizing a reaction between a hydroxyl group and an isocyanate For example, a reaction product of a compound having a polymerizable unsaturated bond and a hydroxyl group in one molecule and a diisocyanate compound is reacted with a hydroxyl group in the copolymer.

The carboxyl group-containing (meth) acrylic copolymer has an acid value of 0.5 to 3.0 meq / g.
It is. If it is less than 0.5 meq / g, the alkali solubility (developability) of the unexposed portion (non-polymerized portion) of the resist coating film becomes low and a good pattern cannot be obtained.
If it exceeds eq / g, on the contrary, the alkali resistance of the exposed portion (polymerized portion) is lowered, so that not only a good pattern cannot be formed, but also the skirt of the pattern is easily generated.

[0013] The required performance of the resist coating film is as follows:
When performing close contact exposure using a pattern film, there is no tackiness of the coating film. In this regard, the glass transition point (hereinafter referred to as “Tg”) of the carboxyl group-containing (meth) acrylic copolymer has a very large effect on the tackiness of the resist coating film.
It is preferable that it is in an appropriate range. However, regarding the tackiness of the coating film, the Tg of (meth) acrylate, which is another component constituting the photopolymerizable resin composition of the present invention, is used.
Is also affected by these factors.
g must be determined. Generally, if the Tg is too high, the alkali solubility (developability) of the resist coating film decreases,
If the Tg is too low, tackiness is exhibited, so the Tg of the carboxyl group-containing (meth) acrylic copolymer is from 30 ° C to
100 ° C. is preferred.

Examples of the (meth) acrylic copolymer containing a carboxyl group include α, such as acrylic acid and / or methacrylic acid (hereinafter referred to as “(meth) acrylic acid”).
β-unsaturated carboxylic acid as an essential component and (meth)
Acrylates, for example the respective esters of (meth) acrylic acid such as methyl, ethyl, propyl, butyl, isobutyl, hydroxyethyl or cyclohexyl, and / or other acrylics such as acrylonitrile, methacrylonitrile, acrylamide or methacrylamide and And / or a methacrylic unsaturated monomer is copolymerized, and other vinylic unsaturated monomers such as styrene and vinyl acetate may be optionally copolymerized.

(Meth) acrylate has one or more ethylenically unsaturated groups in one molecule, and can increase the crosslink density of a coating film obtained from the photopolymerizable resin composition of the present invention, and can improve flexibility. In order to increase the crosslink density, a compound having two or more ethylenically unsaturated groups in one molecule is used. Examples thereof include diethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and the like. .

The mixing ratio of the (meth) acrylic copolymer containing a carboxyl group and the (meth) acrylate varies depending on the unsaturated equivalent of each component, Tg, acid value and the like. Assuming that the total of both components is 1, the carboxyl group-containing (meth) acrylic copolymer is 50 to 50%.
90% by weight, 10 to 50% by weight of (meth) acrylate
Is preferable. (Meth) acrylic copolymer is 50
When the amount is 90% by weight, the cross-linking density of the coating film is undesirably reduced.

The organic polyamine compound to be blended in the photopolymerizable resin composition of the present invention has two or more amino groups in one molecule, and the type thereof is not particularly limited. Ethylenediamine, trimethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, diaminocyclohexane, diaminobenzoic acid, diaminodiphenylether , Diaminodiphenyl ether, diaminohydroxypropane, diaminonaphthalene, toluenediamine and the like. Also,
Diamines and triamines having a high molecular weight polymer skeleton, various diamines having an aromatic skeleton, and the like can also be used.

The compounding amount of the organic polyamine compound having two or more amino groups in one molecule may be 1 to 9 of the carboxyl groups of the carboxyl group-containing (meth) acrylic copolymer.
0% neutralizing amount (1-90 with respect to the acid value of the copolymer)
Mol%). If the compounding amount is small, ionic crosslinking is insufficient and curing for improving flexibility is not sufficiently exhibited, while if too large, the alkali resistance of the exposed portion (polymerized portion) is lowered and a good pattern can be formed. Can not. Preferably, it is 8-80%.

Various generally known photopolymerization initiators can be used. For example, benzoin, benzoin methyl ether, benzyl, diphenyl disulfide, eosine, thionine, diacetyl, Michler's ketone, α-aminoacetophenone, anthraquinone, thioxanthone, benzophenone and the like can be used, and if necessary, two or more of these can be used in combination. The amount of these used is the total amount of the carboxyl group-containing (meth) acrylic copolymer and (meth) acrylate by 10
As 0 parts by weight, a range of 0.1 to 10 parts by weight is preferable. If the amount is less than 0.1 part by weight, the polymerization may be incomplete. If the amount exceeds 10 parts by weight, the component may not be sufficiently dissolved in the photopolymerizable resin composition. When a photopolymerization initiator is used, a photopolymerization sensitizer can be used in combination.

Further, when the resin composition is used as a liquid photo-etching resist, it is preferable to dilute the resin composition with an appropriate organic solvent. The organic solvent to be used is not particularly limited as long as the resin component is soluble, but an organic solvent having properties substantially matching the resist coating apparatus and the coating conditions, drying conditions, etc. is used. You. In addition, the amount of use is determined so as to have a viscosity or NV (solid concentration) suitable for the applied coating method. In addition, about each said organic solvent, what was used as a solvent at the time of synthesize | combining the carboxyl group containing (meth) acrylic copolymer which comprises the said photopolymerizable composition is used as the said composition. It is also possible to mix them inside.

Further, the photopolymerizable resin composition of the present invention comprises:
If necessary, various additives such as a dye, an adhesion improver, a softening agent, a leveling agent or an antifoaming agent may be added. As these additives, those usually used in the fields of inks, resists, paints and the like can be used, and it is preferable to add them in an amount of 30% by weight or less based on the solid content in the composition. .

[0022]

The present invention will now be described more specifically with reference to examples and comparative examples. In the following description, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified. The acid value of the resin is the measurement result by titration with a 0.1N aqueous solution of sodium hydroxide, and the weight average molecular weight is the measurement result by GPC.

Synthesis Example 1 43 parts of methyl methacrylate, 20 parts of n-butyl methacrylate, 13 parts of methacrylic acid, 8 parts of styrene, 16 parts of 2-hydroxyethyl acrylate, 0.7 parts of azobisisobutyronitrile and 6 parts of dodecyl mercaptan Was added dropwise over 75 hours to 75 parts of isopropanol kept at a temperature of 80 ° C. under a nitrogen atmosphere. Thereafter, the mixture was aged for 1 hour, and further 0.3 parts of azobisisobutyronitrile and 5 parts of isopropanol were added and aged for 2 hours. While blowing air into the resin solution, 5 parts of glycidyl methacrylate, 20 parts of isopropanol, 1.5 parts of dimethylbenzylamine as a catalyst and 0.3 part of hydroquinone as a polymerization inhibitor were added, and the temperature was 80 ° C.
For 10 hours to obtain a carboxyl group-containing (meth) acrylic copolymer solution. The carboxyl group-containing (meth) acrylic copolymer has an acid value of 1.10 meq / g in terms of solids, a weight average molecular weight of 6,000, and an unsaturated equivalent of 0.3 meq / g in terms of solids. Met.

Synthesis Example 2 35 parts of methyl methacrylate, 16 parts of isobutyl methacrylate, 14 parts of acrylic acid, 10 parts of methacrylic acid, 9 parts of styrene, 2-hydroxyethyl methacrylate 16
Of a azobisisobutyronitrile and 1.8 parts of azobisisobutyronitrile was dropped into 75 parts of isopropanol kept at a temperature of 80 ° C. in a nitrogen atmosphere over 5 hours. Thereafter, the mixture was aged for 1 hour, and further 0.4 parts of azobisisobutyronitrile and 5 parts of isopropanol were added and aged for 2 hours.
While blowing air into the resin solution, 15 parts of glycidyl methacrylate, 20 parts of isopropanol, 1.5 parts of dimethylbenzylamine as a catalyst, and 0.3 parts of phenothiazine as a polymerization inhibitor were added, and reacted at a temperature of 80 ° C. for 9 hours. A group-containing (meth) acrylic copolymer solution was obtained. This carboxyl group-containing (meth) acrylic copolymer has an acid value of 1.78 me in terms of solid content.
q / g, the weight average molecular weight was 34,000, and the unsaturated equivalent was 0.9 meq / g in terms of solid content.

Synthesis Example 3 Methyl methacrylate 45 parts, methyl acrylate 25
Propylene glycol monomethyl ether obtained by maintaining a mixed solution consisting of 1 part, 14 parts of acrylic acid, 16 parts of 2-hydroxyethyl acrylate, 0.7 part of azobisisobutyronitrile and 3 parts of dodecyl mercaptan at 80 ° C. under a nitrogen atmosphere. It was added dropwise to 95 parts over 5 hours. Thereafter, the mixture was aged for 1 hour, further added with 0.3 parts of azobisisobutyronitrile and 5 parts of propylene glycol monomethyl ether, and aged for 2 hours to synthesize a resin solution of a carboxyl group-containing (meth) acrylic copolymer. The carboxyl group-containing (meth) acrylic copolymer has an acid value of 1.9 meq / g in terms of solid content and a weight average molecular weight of 1
The unsaturated equivalent was 1,000 meq / g in terms of solid content.

Example 1 9.4 parts of the carboxyl group-containing (meth) acrylic copolymer solution of Synthesis Example 1, 1.3 parts of pentaerythritol triacrylate, and α-aminoacetophenone (trade name Irgacure 907: manufactured by Ciba Geigy) 0.3 parts and 4 parts of propylene glycol monomethyl ether are sufficiently mixed and dissolved, and then 0.1 part of ethylenediamine (corresponding to 30 mol% of the carboxyl groups contained in the (meth) acrylic copolymer of Synthesis Example 1: (A degree of 30%) was dissolved in 4.3 parts of propylene glycol monomethyl ether. Further, a blue dye (methylene blue) was added to this composition to obtain a photopolymerizable resin composition having an NV of about 35%.

Example 2 Example 1 was repeated except that ethylene diamine was used in an amount of 0.16 part (corresponding to 50 mol% of the carboxyl groups contained in the (meth) acrylic copolymer of Synthesis Example 1; the degree of neutralization was 50%). Similarly, a photopolymerizable resin composition was obtained.

Example 3 The procedure of Example 1 was repeated except that ethylenediamine was used in an amount of 0.23 parts (corresponding to 70 mol% of the carboxyl groups contained in the (meth) acrylic copolymer of Synthesis Example 1; neutralization degree 70%). Similarly, a photopolymerizable resin composition was obtained.

Example 4 14 parts of the carboxyl group-containing (meth) acrylic copolymer solution obtained in Synthesis Example 1, 1.9 parts of dipentaerythritol pentaacrylate, 0.5 parts of Irgacure 907 and 4.5 parts of methyl ethyl ketone were sufficiently added. Then, 0.2 parts of polypropylene glycol diamine having a molecular weight of 230 (corresponding to 10 mol% of the carboxyl groups contained in the (meth) acrylic copolymer of Synthesis Example 1; degree of neutralization: 10)
%) In 7.8 parts of methyl ethyl ketone. Further, a blue dye (methylene blue) was added to this composition to obtain a photopolymerizable resin composition having an NV of about 35%.

Example 5 14.6 parts of the carboxyl group-containing (meth) acrylic copolymer solution of Synthesis Example 3, 1.3 parts of dipentaerythritol pentaacrylate, 0.4 parts of Irgacure 907 and 3 parts of ethyl acetate 2. Thoroughly mix and dissolve, then propylene glycol triamine with a molecular weight of 5000
A solution prepared by dissolving 5 parts (corresponding to 5 mol% of the carboxyl groups contained in the (meth) acrylic copolymer of Synthesis Example 1: degree of neutralization 5%) in 7 parts of ethyl acetate was added. Further, a blue dye (methylene blue) is blended with this composition,
A photopolymerizable resin composition having a V of about 30% was obtained.

Comparative Example 1 A photopolymerizable resin composition was obtained in the same manner as in Example 1 except that ethylenediamine was not blended.

Comparative Example 2 A photopolymerizable resin composition was obtained in the same manner as in Example 1, except that the amount of ethylenediamine was changed to 0.3 part (neutralization degree: 100%).

Comparative Example 3 A photopolymerizable resin composition was obtained in the same manner as in Comparative Example 1 except that the resin solution of Synthesis Example 2 was used (neutralization degree 0).
%).

Evaluation Results Each resin composition was measured for viscosity and evaluated as an etching resist. The results are summarized in Table 1.

(1) Viscosity measurement The viscosity was measured at 25 ° C. using an E-type viscometer. If ionic crosslinking occurs with the added diamine, an increase in viscosity is observed. (2) Pattern forming property Each composition was applied on a copper-clad laminate with a bar coater,
After drying at 0 ° C. for 10 minutes, a coating film of 10 μm was obtained. After that, 100 mJ / cm ² exposure using a pattern film, 3
The resist pattern was formed by developing with a 1% aqueous solution of sodium carbonate at 0 ° C. for 60 seconds. This resist pattern was observed with an electron microscope to observe the pattern shape and whether there was any footing. (3) Flexibility A 10 μm coating film was formed on the copper-clad laminate in the same manner as in (1), and the entire surface was exposed to 100 mJ / cm ^{2 and} exposed to 6 m in the same manner as (1).
Development was performed for 0 seconds. Thereafter, the sheet is cut in a grid according to the method described in JIS-K5400, and the cellophane tape is peeled off. The flexibility was evaluated by observing the degree of cracking of the coating film at each cut portion.

[0036]

[Table 1]

1) Pattern formability ○: good pattern shape without skirting △: slight skirting at the lower end of pattern ×: significant skirting at the lower end of pattern 2) flexibility ○: No crack on the resist edge cut on the grid, the first coat is completely adhered to the substrate △: Little crack on the resist edge cut on the grid, the first coat There is some peeling at the edge. C: The resist end surface cut in a grid pattern has large cracks, and the coating film at a glance has largely peeled off. 3) Evaluation was stopped because the developing solution resistance in the exposed area tended to deteriorate and the surface of the coating film after development became rough.

As a result of the evaluation, the state of ionic crosslinking due to the blending of the diamine was confirmed from the increase in viscosity of each resin composition. The addition of the diamine improved the flexibility of the resist coating film, while showing good pattern formation without any adverse effect.

[0039]

The composition obtained according to the present invention is a photopolymerizable resin composition having improved flexibility, excellent developability and excellent peelability without impairing the pattern formability as a liquid etching resist. .

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03F 7/033 G03F 7/033 H05K 3/06 H05K 3/06 H

Claims (1)

[Claims] 1. A) A polystyrene equivalent weight average molecular weight of 3,000 to 20,000 and an unsaturated equivalent of 0 to 2.0.
meq / g, and a carboxyl group-containing acrylic copolymer and / or methacrylic copolymer having an acid value of 0.5 to 3.0 meq / g; B) acrylate and / or methacrylate; C) organic polyvalent amine A compound; D) a photopolymerization initiator; as an essential component, and 1 to 9 carboxyl groups in the component A).
A photopolymerizable resin composition, wherein 0% is neutralized by the component (C).