JP6983363B2 - How to reuse the base material for wiring boards - Google Patents

Description

The present invention relates to a method for reusing a base material for a wiring board. More specifically, the present invention recycles a base material by removing a part or all of the cured coating from a wiring board having a cured coating formed on the surface of the base material. Regarding how to use it.

For the purpose of protecting the conductor circuit and preventing solder from adhering to places other than those requiring soldering, a circuit board having a cured film formed only on a desired portion of the surface of a printed wiring board is manufactured. .. As a method for forming a cured film, a photosensitive resin composition is applied on a substrate, dried, exposed and developed, and a cured film is formed only on a desired portion of the substrate surface, or a so-called dry film. The mainstream method is to attach a film provided with a photosensitive resin layer called, to a substrate, and to form a cured film only on a desired portion of the surface of the substrate by exposure and development.

By the way, in the process of forming the cured film on the base material, some defects that lead to deterioration of the quality of the product may occur. For example, printing defects when applying a photosensitive resin composition called solder resist ink to a substrate, misalignment during exposure, color unevenness (color unevenness), pinholes in a dry coating film, contamination with foreign matter, marking ink Problems such as printing defects may occur. In such a defect in the cured film forming step, it is possible to easily remove the coating with a developing solution before exposure. Further, even after exposure and development, if the coating film is not cured by heat treatment, the developed coating film is peeled off with an appropriate solvent, and the photosensitive resin composition is applied onto the substrate again. The defect can be corrected by performing exposure and development processing after drying. On the other hand, if the developed coating film is heat-treated to form a cured film, it is not easy to completely peel off the cured film from the substrate with a solvent. The reason is that a crosslinked structure is formed by the crosslinking reaction of the photocurable component contained in the photosensitive resin composition.

When the above-mentioned defects occur in the process of forming the cured film, if the defective product is discarded, the base material is wasted and the productivity (yield) of the product is lowered. Recently, since circuit wiring boards using high value-added base materials have been manufactured, there is a potential desire to reuse the base materials in the event of a defect.

Therefore, a method of reusing the base material when a defect occurs during the process of forming the cured film has been proposed. For example, in Patent Document 1, when a defect is found in the coating film after development and exposure (before the coating film is cured by heat treatment), the base material provided with the coating film is immersed in a stripping solution consisting of a specific alkaline aqueous solution. However, it has been proposed that the substrate can be reused by peeling the coating film from the substrate. However, with this method, if a defect is found in the cured coating film that has undergone the curing treatment after exposure and development, the cured coating film cannot be peeled off from the substrate. Therefore, various studies have been made on a stripping solution that enables the reuse of the base material even after the developed coating film is cured. For example, in Patent Document 2, after the coating film is cured after development by using a stripping solution composed of a mixed solution of an alkali metal hydroxide and an aprotic solvent (for example, N-methylpyrrolidone). However, a method has been proposed in which the cured coating film can be peeled off from the substrate.

However, in recent years, there has been a further demand for improvement of the cured film characteristics such as the adhesion between the base material and the cured film, and a photosensitive resin composition containing a thermosetting component such as an epoxy resin is used. It is starting to be used. Therefore, it is becoming more and more difficult to peel off the cured film in which a defect is found from the base material. Under such circumstances, for example, Patent Document 3 proposes that the cured film can be peeled off from the substrate even with an alkaline aqueous solution by blending a curable component derived from a specific polyester with the photosensitive resin composition. ing.

Japanese Unexamined Patent Publication No. 7-115048 Japanese Unexamined Patent Publication No. 11-145594 Japanese Unexamined Patent Publication No. 2015-288646

In the method proposed in Patent Document 2 described above, the wiring board on which the cured film is formed is immersed in a stripping solution to remove the cured film, so that the cured film is cured even if only a small part of the cured film has a defect. The entire coating will be peeled off, resulting in waste of material. For example, if the cured film can be removed only at the defective portion, it can be said that the base material can be efficiently reused.

Further, the method for reusing a base material proposed in Patent Document 3 focuses on the composition of the photosensitive resin composition and makes it easy to peel off the cured film from the base material by blending a specific component. .. However, depending on the general photosensitive resin composition (solder resist ink containing a thermosetting component, etc.) that has begun to be used in recent years, it is difficult to change the composition, and the method of Patent Document 3 may not be applicable.

Therefore, an object of the present invention is that when a defect is found in a part of the cured coating when manufacturing a wiring board having a cured coating on the substrate, the cured coating can be removed from the substrate only in the defective portion. It is an object of the present invention to provide a method capable of removing a cured film from a substrate regardless of the composition of the photosensitive resin composition.

To solve the above problems, the present inventors have general-purpose by irradiating the cured film with a predetermined active energy ray in the presence of oxygen, even if the cured film is formed through a curing process after exposure and development. It was found that the cured film can be easily peeled off from the substrate by a solvent. The present invention has been completed based on such findings. That is, the gist of the present invention is as follows.

[1] A method of removing a part or all of the cured coating from a wiring board having a cured coating formed on the surface of the substrate and reusing the substrate.
The cured film is made of a cured product of a photosensitive resin composition.
A step of irradiating a part or all of the cured film with at least one of an active energy ray capable of generating active oxygen in the presence of oxygen and an active energy ray capable of cleaving a CC carbon bond.
A step of washing the base material on which the cured film is formed with a solvent and removing the cured film of the portion irradiated with the active energy ray from the base material.
A method for reusing a base material for a wiring board, including.
[2] The cured film was formed by applying a photosensitive resin composition on the substrate and drying it to form a dry coating film, or by applying the photosensitive resin composition to a support film and drying it. A dry film having a resin layer is bonded to the dry film so that the base material and the resin layer are in contact with each other, and then the dry coating film or the resin layer of the dry film is exposed, developed, and patterned. The method according to [1], which is formed by.
[3] The method according to [1] or [2], wherein the active energy ray contains ionizing radiation having a wavelength of 100 to 255 nm.
[4] The method according to any one of [1] to [3], further comprising a step of heating the wiring substrate from which the cured film has been removed.
[5] The method according to any one of [1] to [4], wherein the solvent is an aprotic polar solvent.
[6] The photosensitive resin composition contains (A) a carboxyl group-containing resin, (B) a photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting component, [1] to The method according to any one of [5].
[7] Any of [1] to [6], wherein at least one of heating and ultraviolet irradiation is performed after the exposure and development of the resin layer and before the irradiation of the cured film with active energy rays. The method described.
[8] The method according to any one of [1] to [7], wherein the cured film has a thickness of 1 to 1000 μm.

According to the present invention, even in a cured film made of a cured product of a photosensitive resin composition, an active energy ray capable of generating active oxygen in the presence of oxygen and an active energy ray capable of cleaving a CC carbon bond can be obtained. By irradiating the cured film with at least one of them, the cured film can be removed from the substrate regardless of the composition of the photosensitive resin composition. In addition, since the active energy rays can be irradiated only to the defective part of the cured film, if a defect is found in a part of the cured film during manufacturing of the wiring board, only the defective part is the cured film. Can be removed from the substrate.

The method for reusing a base material for a wiring substrate according to the present invention is a method of removing a part or all of the cured coating from a wiring substrate having a cured coating formed on the surface of the base material and reusing the base material. (1) Part or all of the cured film is irradiated with at least one of an active energy ray capable of generating active oxygen in the presence of oxygen and an active energy ray capable of cleaving a CC carbon bond. Process and
(2) A step of washing the base material on which the cured film is formed with a solvent to remove the cured film of the portion irradiated with the active energy ray from the base material.
Is included.

In the present invention, a part or all of the cured film made of a cured product of the photosensitive resin composition formed on the substrate is irradiated with the above-mentioned specific active energy rays. Only the portion can be easily and easily removed from the cured film with a solvent. That is, even when the photosensitive resin composition contains a cross-linking component such as a photopolymerizable monomer or a thermosetting component such as an epoxy resin, the photosensitive resin composition is cured. By irradiating the cured film with an active energy ray capable of generating active oxygen in the presence of oxygen or an active energy ray capable of cleaving a CC carbon bond, the cured film (polymer of a photosensitive resin composition). The CC carbon bond of the polymer chain constituting the cured product is cleaved, or the CC carbon bond of the polymer chain constituting the cured product is cleaved by the active oxygen generated by irradiation with the active energy ray. As a result, some of the cleaved hydrocarbon radicals combine with oxygen in the presence of oxygen and become carbon dioxide or the like and vaporize. In addition, hydrocarbon radicals may recombine to form low molecular weight compounds, and some of these low molecular weight compounds are vaporized. Furthermore, when the CC carbon bond in the polymer chain is cleaved, the molecular weight decreases, so that the cured film itself becomes embrittled. Furthermore, even if the polymer chain has a crosslinked structure in the cured film, the CC carbon bond in the crosslinked portion is cleaved by irradiation with active energy rays or active oxygen, so that the polymer chain is soluble in the solvent. It becomes. In the prior art, attention has been focused on preparing a solvent that can be easily peeled off or preparing a photosensitive composition that can obtain a cured film that can be easily peeled off by the solvent, but the present invention is different from any of the prior arts. We have found a completely new method. According to the present invention, the cured film can be removed from the substrate regardless of the composition of the photosensitive resin composition, and the irradiation of the active energy ray can be applied only to the defective portion of the cured film. Therefore, when a defect is found in a part of the cured film during manufacturing of the wiring substrate, the cured film can be removed from the base material only in the defective portion. Hereinafter, each step of the method for reusing the base material for a wiring board according to the present invention will be described.

[Wiring board]
As described above, the present invention provides a method of removing a part or all of the cured coating from a wiring board having a cured coating formed on the surface of the substrate and reusing the substrate. That is, the present invention provides a method for removing only the defective cured film when a defect is found in a part of the cured film in the manufacturing process of the wiring board forming the cured film. First, a wiring board will be described by forming a cured film on the base material.

As a step of forming a cured coating film on a substrate to prepare a wiring board, a method of forming a cured coating film by curing the coating film after exposure and development of a coating film such as a printed wiring board on which a solder resist layer is formed. Can be applied without limitation. Hereinafter, a general method for forming a cured film on a substrate will be described.

First, a photosensitive resin composition is applied onto a substrate and dried to form a dry coating film, or a dry film having a resin layer formed by applying a photosensitive resin composition to a support film and drying is formed. , The dry film is bonded so that the base material and the resin layer are in contact with each other. Next, the resin layer of the dry coating film or the dry film is exposed and developed to form a cured film on the substrate. When forming a cured film using a dry film, it is preferable to peel off the support film from the resin layer either before or after exposure.

<Base material>
As the base material, in addition to printed wiring boards and flexible printed wiring boards whose circuits are formed in advance with copper or the like, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, etc. It is made of materials such as copper-clad laminates for high-frequency circuits using synthetic fiber epoxy, fluororesin / polyethylene / polyimideene ether, polyphenylene oxide / cyanate, etc., and all grades (FR-4, etc.) of copper-clad laminates. In addition, a wafer substrate, a metal substrate, a polyimide film, a polyethylene terephthalate film, a polyethylene naphthalate (PEN) film, a glass substrate, a ceramic substrate, a wafer plate and the like can be mentioned. Of these, a copper-clad laminate is particularly preferable.

When a copper-clad laminate or the like is used as a base material, it is preferable to polish the surface of the copper foil in order to improve the adhesion between the base material and the cured film. Examples of polishing include physical polishing of buffs, scrubs, brushes and the like, chemical polishing of CZ8101 and the like. The arithmetic average surface roughness (Ra) of the surface of the copper foil after polishing is preferably 50 to 1000 nm. According to the method of the present invention, even such a cured film having increased adhesion to the substrate can be easily removed by a solvent.

<Photosensitive resin composition>
The photosensitive resin composition is patterned by exposure and development to form a cured film provided on the substrate. As such a photosensitive resin composition, for example, a conventionally known solder resist ink or the like can be used without limitation, but an example of a photosensitive resin composition that can be preferably used in the present invention will be described below.

In the present invention, a photosensitive resin composition containing (A) a carboxyl group-containing resin, (B) a photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting component is preferably used. Can be done.

As the (A) carboxyl group-containing resin, various conventionally known photosensitive resins having a carboxyl group in the molecule can be used. When the photosensitive resin composition contains (A) a carboxyl group-containing resin, alkali developability can be imparted to the photosensitive resin composition. In particular, a carboxyl group-containing photosensitive resin having a (meth) acryloyl group in the molecule is preferable from the viewpoint of photocurability and development resistance. The (meth) acryloyl group is preferably derived from acrylic acid or methacrylic acid or a derivative thereof. Specific examples of the (A) carboxyl group-containing resin include the following compounds (either oligomer or polymer). In addition, in this specification, a (meth) acryloyl group is a term which collectively refers to an acryloyl group, a meta-acryloyl group and a mixture thereof, and the same applies to other similar expressions.

(1) A carboxyl group-containing resin obtained by copolymerizing an unsaturated carboxylic acid such as (meth) acrylic acid with an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth) acrylate, and isobutylene.

(2) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates and aromatic diisocyanates, carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate-based polyols and polyether-based compounds. A carboxyl group-containing urethane resin obtained by a double addition reaction of a diol compound such as a polyol, a polyester-based polyol, a polyolefin-based polyol, an acrylic polyol, a bisphenol A-based alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

(3) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( Meta) A carboxyl group-containing photosensitive urethane resin obtained by a double addition reaction of an acrylate or a modified partial acid anhydride thereof, a carboxyl group-containing dialcohol compound and a diol compound.

(4) During the synthesis of the resin according to (2) or (3), a compound having one hydroxyl group and one or more (meth) acryloyl groups in a molecule such as hydroxyalkyl (meth) acrylate is added to the terminal (4). Meta) Acryloylated carboxyl group-containing photosensitive urethane resin.

(5) During the synthesis of the resin according to (2) or (3), one isocyanate group and one or more (meth) acryloyl groups are formed in the molecule, such as an isophorone diisocyanate and a pentaerythritol triacrylate homomolar reaction product. Carboxyl group-containing photosensitive urethane resin that is terminal (meth) acrylicized by adding the compound to be possessed.

(6) A carboxyl group-containing photosensitive resin obtained by reacting a bifunctional or higher polyfunctional (solid) epoxy resin with (meth) acrylic acid and adding a dibasic acid anhydride to a hydroxyl group existing in a side chain.

(7) Carboxyl in which a (meth) acrylic acid is reacted with a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl group of a bifunctional (solid) epoxy resin with epichlorohydrin, and a dibasic acid anhydride is added to the generated hydroxyl group. Group-containing photosensitive resin.

(8) A dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid is reacted with a bifunctional oxetane resin, and the generated primary hydroxyl group is subjected to two bases such as phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride. Carboxyl group-containing polyester resin to which acid anhydride is added.

(9) An epoxy compound having a plurality of epoxy groups in one molecule, a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule such as p-hydroxyphenethyl alcohol, and (meth). Reacting with unsaturated group-containing monocarboxylic acid such as acrylic acid, maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipine with respect to the alcoholic hydroxyl group of the obtained reaction product. A carboxyl group-containing photosensitive resin obtained by reacting a polybasic acid anhydride such as an acid.

(10) Reaction obtained by reacting a reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide with an unsaturated group-containing monocarboxylic acid. A carboxyl group-containing photosensitive resin obtained by reacting a product with a polybasic acid anhydride.

(11) Reaction obtained by reacting a reaction organism obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate with an unsaturated group-containing monocarboxylic acid. A carboxyl group-containing photosensitive resin obtained by reacting a product with a polybasic acid anhydride.

(12) A carboxyl group-containing photosensitive resin obtained by further adding a compound having one epoxy group and one or more (meth) acryloyl groups in one molecule to the resins (1) to (11).

The (A) carboxyl group-containing resin that can be used in the present invention is not limited to those listed above. also. One type of the (A) carboxyl group-containing resin listed above may be used alone, or a plurality of types may be mixed and used.

The weight average molecular weight of the (A) carboxyl group-containing resin varies depending on the resin skeleton, but is generally in the range of 2,000 to 150,000, preferably in the range of 5,000 to 100,000. By using the (A) carboxyl group-containing resin having a weight average molecular weight of 2,000 or more, the resolution and the tack-free performance can be improved. Further, by using the (A) carboxyl group-containing resin having a weight average molecular weight of 150,000 or less, developability and storage stability can be improved.

The blending amount of the (A) carboxyl group-containing resin is 50 to 90 parts by mass when the total amount of the (A) carboxyl group-containing resin and (D) thermosetting component is 100 parts by mass in terms of solid content. It is preferable to have. (A) By setting the blending amount of the carboxyl group-containing resin within the above range, the state change of the coating film surface with time becomes appropriate, and the adhesion to the substrate can be further improved. According to the method of the present invention, even such a cured film having increased adhesion to the substrate can be easily removed by a solvent.

The (B) photopolymerizable monomer contained in the photosensitive resin composition is a monomer having an ethylenically unsaturated double bond. Examples of the (B) photopolymerizable monomer include known and commonly used polyester (meth) acrylates, polyether (meth) acrylates, urethane (meth) acrylates, carbonate (meth) acrylates, and epoxy (meth) acrylates. Specifically, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol and propylene glycol; N, N-dimethylacrylamide. , N-methylolacrylamide, acrylamides such as N, N-dimethylaminopropylacrylamide; aminoalkyl acrylates such as N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl acrylate; Polyhydric alcohols such as pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate or polyhydric acrylates such as ethireoxyside adducts, propylene oxide adducts, or ε-caprolactone adducts thereof; phenoxyacrylates, bisphenol A di. Polyvalent acrylates such as acrylates and ethylene oxide adducts or propylene oxide adducts of these phenols; Polyvalent acrylates; Not limited to the above, acrylates and melamine acrylates obtained by directly acrylated polyols such as polyether polyols, polycarbonate diols, hydroxyl group-terminated polybutadienes, polyester polyols, or urethane acrylates via diisocyanates, and the acrylates. Can be appropriately selected and used from at least one of each methacrylate corresponding to the above. Such a photopolymerizable monomer (B) can also be used as a reactive diluent.

An epoxy acrylate resin obtained by reacting a polyfunctional epoxy resin such as cresol novolac type epoxy resin with acrylic acid, and a hydroxy acrylate such as pentaerythritol triacrylate and a diisocyanate half urethane such as isophorone diisocyanate on the hydroxyl group of the epoxy acrylate resin. An epoxy urethane acrylate compound obtained by reacting the compound or the like may be used as the (B) photopolymerizable monomer. Such an epoxy acrylate compound can improve the photocurability without lowering the dryness to the touch.

The blending amount of the (B) photopolymerizable monomer is preferably 10 to 50 parts by mass with respect to 100 parts by mass of the (A) carboxy-containing resin, and more preferably 15 to 45 parts by mass in terms of solid content. preferable. (B) By setting the blending amount of the photopolymerizable monomer to 10 parts by mass or more, the photocurability of the photosensitive resin composition is improved. Further, by setting the blending amount to 50 parts by mass or less, the resolution of the cured film can be improved.

(B) The photopolymerizable monomer is (B) a photopolymerizable monomer in order to make the composition photocurable, especially when a carboxyl group-containing non-photosensitive resin having no ethylenically unsaturated double bond is used. It is effective because it is necessary to use together.

The (C) photopolymerization initiator contained in the photosensitive resin composition is for reacting the above-mentioned (A) carboxyl group-containing resin and (B) photopolymerizable monomer by exposure. (C) As the photopolymerization initiator, any known photopolymerization initiator can be used. (C) As the photopolymerization initiator, one type may be used alone, or two or more types may be used in combination.

Specific examples of the (C) photopolymerization initiator include bis- (2,6-dichlorobenzoyl) phenylphosphine oxide and bis- (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine. Oxide, bis- (2,6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis- (2,6-dimethoxybenzoyl) phenyl Phosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,5-dimethylphenylphosphinoxide, bis- Bisacylphosphine oxides such as (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4 Monoacylphosphine oxides such as 6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide Ethyl phenyl (2,4,6-trimethylbenzoyl) phosphinate, 1-hydroxy-cyclohexylphenylketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane -1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1-one, 2-hydroxy-2- Hydroxyacetophenones such as methyl-1-phenylpropane-1-one; benzoyls such as benzoin, benzyl, benzoinmethyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether; benzoin alkyl ether Kind; Benzoyls such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone; acetophenone, 2,2-dimethoxy-2-fe Nylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanol , 2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl) -1- [4- (4) -Molholinyl) phenyl] -1-butanone, N, N-dimethylaminoacetophenone and other acetophenones; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2- Thioxanthons such as chlorothioxanthone, 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone. Anthracinones such as acetophenone dimethyl ketal, ketals such as benzyl dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2- (dimethylamino) ethyl benzoate, p-dimethylbenzoic acid ethyl ester; 1, 2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl ] -, 1- (O-Acetyloxym) and other oxime esters; bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-) Il) phenyl) Titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3- (2- (1-pyll-1-yl) ethyl) phenyl] Titanosen such as titanium; phenyldisulfide2- Examples thereof include nitrofluorene, butyloin, anisoine ethyl ether, azobisisobutyronitrile, tetramethylthium disulfide and the like.

Examples of commercially available α-aminoacetophenone-based photopolymerization initiators include Omnirad 907, 369, 369E, and 379 manufactured by IGM Resins. Examples of commercially available acylphosphine oxide-based photopolymerization initiators include Omnirad TPO H and 819 manufactured by IGM Resins. Commercially available products of oxime ester-based photopolymerization initiators include Irgacure OXE01 and OXE02 manufactured by BASF Japan Ltd., N-1919 manufactured by ADEKA Corporation, NCI-831 and NCI-831E manufactured by ADEKA CORPORATION, and Changzhou Strong Electronics New Materials Co., Ltd. TR-PBG-304 and the like can be mentioned.

In addition, JP-A-2004-359639, JP-A-2005-097141, JP-A-2005-22297, JP-A-2006-160634, JP-A-2008-094770, JP-A-2008-509967, Examples thereof include carbazole oxime ester compounds described in JP-A-2009-040762 and JP-A-2011-80036.

The blending amount of the (C) photopolymerization initiator is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the (A) carboxyl group-containing resin in terms of solid content. When the amount is 1 part by mass or more, the photocurability of the photosensitive resin composition is good, and the film characteristics such as chemical resistance are also good. Further, when the amount is 20 parts by mass or less, the effect of reducing outgas is obtained, the light absorption on the surface of the cured film is good, and the deep curability is less likely to decrease. More preferably, it is 2 to 15 parts by mass.

Further, in the present invention, a photoinitiator aid or a sensitizer may be used in combination with the (C) photopolymerization initiator. Examples of the photoinitiator aid or sensitizer include benzoin compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, tertiary amine compounds, and xanthone compounds. In particular, it is preferable to use a thioxanthone compound such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone. By containing the thioxanthone compound, deep curability can be improved. Although these compounds may be used as (C) a photopolymerization initiator, they are preferably used in combination with (C) a photopolymerization initiator. In addition, one type of photoinitiator aid or sensitizer may be used alone, or two or more types may be used in combination.

Since these (C) photopolymerization initiators, photoinitiator aids, and sensitizers absorb specific wavelengths, they may have low sensitivity in some cases and may function as ultraviolet absorbers. However, these are not used only for the purpose of improving the sensitivity of the photosensitive resin composition. It absorbs light of a specific wavelength as needed to increase the photoreactivity of the surface, change the line shape and aperture of the resist pattern to vertical, tapered, or reverse tapered, and the accuracy of the line width and aperture diameter. Can be improved.

It is preferable that the photosensitive resin composition contains (D) a thermosetting component. (D) By containing the thermosetting component, the barrier property (for example, etching resistance, etc.) of the cured film in the subsequent process is improved, and both the resolution and the peelability can be achieved at a high level. (D) As the thermosetting component, any known one can be used. For example, known compounds such as melamine resin, benzoguanamine resin, melamine derivative, amino resin such as benzoguanamine derivative, isocyanate compound, blocked isocyanate compound, cyclocarbonate compound, epoxy compound, oxetane compound, episulfide resin, bismaleimide, carbodiimide resin are used. can. Particularly preferably, a compound having a plurality of cyclic ether groups or cyclic thioether groups (hereinafter, abbreviated as cyclic (thio) ether group) in the molecule can be used. These thermosetting components may be used alone or in combination of two or more.

The compound having a plurality of cyclic (thio) ether groups in the molecule is a compound having a plurality of 3, 4, or 5-membered ring cyclic (thio) ether groups in the molecule, and is, for example, a plurality of epoxys in the molecule. Examples thereof include a compound having a group, that is, a polyfunctional epoxy compound, a compound having a plurality of oxetanyl groups in the molecule, that is, a polyfunctional oxetane compound, and a compound having a plurality of thioether groups in the molecule, that is, an episulfide resin.

Examples of such an epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, and phenol novolac type epoxy resin. Examples thereof include cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin and the like.

Examples of commercially available epoxy resins include jER 828, 806, 807, YX8000, YX8034, 834 manufactured by Mitsubishi Chemical Corporation, YD-128, YDF-170, ZX-1059 manufactured by Nittetsu Chemical & Materials Co., Ltd. Examples thereof include ST-3000, EPICLON 830, 835, 840, 850, N-730A, N-695 manufactured by DIC Corporation, and RE-306 manufactured by Nippon Kayaku Co., Ltd.

Examples of the polyfunctional oxetane compound include bis [(3-methyl-3-oxetanylmethoxy) methyl] ether, bis [(3-ethyl-3-oxetanylmethoxy) methyl] ether, and 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ether. Methyl-3-oxetanylmethoxy) methyl] benzene, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, (3-methyl-3-oxetanyl) methyl acrylate, (3-ethyl-3-3) Polyfunctional oxetane such as oxetanyl) methyl acrylate, (3-methyl-3-oxetanyl) methyl methacrylate, (3-ethyl-3-oxetanyl) methyl methacrylate and their oligomers or copolymers, as well as oxetane alcohols and novolak resins. , Poly (p-hydroxystyrene), cardo-type bisphenols, calix allenes, calix resorcin allenes, etherified products with a resin having a hydroxyl group such as silsesquioxane and the like. In addition, a copolymer of an unsaturated monomer having an oxetane ring and an alkyl (meth) acrylate can also be mentioned.

Examples of the compound having a plurality of cyclic thioether groups in the molecule include bisphenol A type episulfide resin and the like. Further, using the same synthesis method, an episulfide resin in which the oxygen atom of the epoxy group of the novolak type epoxy resin is replaced with a sulfur atom can also be used.

Examples of amino resins such as melamine derivatives and benzoguanamine derivatives include methylol melamine compounds, methylol benzoguanamine compounds, methylol glycol uryl compounds and methylol urea compounds.

As the isocyanate compound, a polyisocyanate compound can be blended. Examples of the polyisocyanate compound include 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate and Aromatic polyisocyanates such as 2,4-tolylene dimer; aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-methylenebis (cyclohexyl isocyanate) and isophorone diisocyanate; bicyclo Alicyclic polyisocyanates such as heptanetriisocyanate; and adducts, burettes, and isocyanurates of the isocyanate compounds mentioned above can be mentioned.

As the blocked isocyanate compound, an addition reaction product of the isocyanate compound and the isocyanate blocking agent can be used. Examples of the isocyanate compound that can react with the isocyanate blocking agent include the above-mentioned polyisocyanate compound and the like. Examples of the isocyanate blocking agent include a phenol-based blocking agent; a lactam-based blocking agent; an active methylene-based blocking agent; an alcohol-based blocking agent; an oxime-based blocking agent; a mercaptan-based blocking agent; an acid amide-based blocking agent; an imide-based blocking agent; Amine-based blocking agents; imidazole-based blocking agents; imine-based blocking agents and the like can be mentioned.

Regarding the blending amount of the (D) thermosetting component, the number of functional groups of the (D) thermosetting component that reacts with respect to 1.0 mol of the carboxyl group contained in the (A) carboxyl group-containing resin is 0.8 to 2. It is preferably 5 mol, more preferably 1.0 to 2.0 mol.

In particular, when an epoxy resin is used as the (D) thermosetting component, the epoxy group of the epoxy resin may be 1.0 to 2.0 mol per 1.0 mol of the carboxyl group of the (A) carboxyl group-containing resin. preferable. By setting the amount to 1 mol or more, it is possible to prevent the residual carboxyl group from remaining in the cured film and obtain good heat resistance, alkali resistance, electrical insulation and the like. Further, by setting the blending amount to 2 mol or less, it is possible to prevent low molecular weight cyclic (thio) ether groups from remaining in the dry coating film and to ensure good strength of the cured film.

The photosensitive resin composition may contain (E) a thermosetting catalyst for accelerating the curing of the above-mentioned (D) thermosetting component. Examples of the thermosetting catalyst (E) include imidazole, 2-methylimidazole, 2-ethyl imidazole, 2-ethyl-4-methyl imidazole, 2-phenyl imidazole, 4-phenyl imidazole, and 1-cyanoethyl-2-phenyl imidazole. , 1- (2-Cyanoethyl) -2-ethyl-4-methylimidazole and other imidazole derivatives; dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N Examples thereof include amine compounds such as −dimethylbenzylamine, 4-methyl-N and N-dimethylbenzylamine, hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. Commercially available products include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (both are trade names of imidazole compounds) manufactured by Shikoku Kasei Kogyo Co., Ltd., and U-CAT manufactured by San Apro Co., Ltd. Examples thereof include 3513N (trade name of dimethylamine-based compound), DBU, DBN, U-CAT SA 102 (all of which are bicyclic amidine compounds and salts thereof).

The compound is not limited to the above-mentioned compound, and may be a thermosetting catalyst (E) of an epoxy resin or an oxetane compound, or one that promotes a reaction between at least one of an epoxy group and an oxetanel group and a carboxyl group. It may be used alone or in combination of two or more. In addition, guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino S-triazine derivatives such as -S-triazine-isosianulic acid adduct and 2,4-diamino-6-methacryloyloxyethyl-S-triazine-isosianulic acid adduct can also be used, preferably as these adhesion-imparting agents. A compound that also functions is used in combination with (E) a thermosetting catalyst.

As the above-mentioned (E) thermosetting catalyst, one type can be used alone or two or more types can be used in combination. From the viewpoint of storage stability of the photosensitive resin composition and heat resistance of the cured film, the blending amount of the (E) thermosetting catalyst is 0. It is preferably 01 to 5 parts by mass, and more preferably 0.05 to 1 part by mass.

A filler can be added to the photosensitive resin composition, if necessary, in order to increase the physical strength of the cured film. As the filler, known inorganic or organic fillers can be used, but barium sulfate, spherical silica, hydrotalcite and talcite are particularly preferably used. Further, in order to obtain flame retardancy, a metal oxide, a metal hydroxide such as aluminum hydroxide, or the like can be used as an extender pigment filler.

Among the above-mentioned fillers, spherical silica can be preferably used. As the spherical silica, it is preferable to use spherical silica having an average particle size of 1 nm to 100 nm, and more preferably, the average particle size is 2 nm to 50 nm. The surface states Ra1 and Ra2 of the cured film can also be adjusted by blending spherical silica having an average particle size as described above. The average particle size is an average particle size (D50) including not only the particle size of the primary particles but also the particle size of the secondary particles (aggregates), and is the value of D50 measured by the laser diffraction method. be. The average particle size can be determined using a measuring device by a laser diffraction method (for example, Microtrac MT3300EXII manufactured by Microtrac Bell Co., Ltd.).

Further, the above-mentioned filler may be surface-treated in order to enhance the dispersibility in the photosensitive resin composition. Aggregation can be suppressed by using a filler that has been surface-treated. The surface treatment method is not particularly limited, and a known and commonly used method may be used. However, the surface of the inorganic filler may be treated with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group. It is preferable to treat it.

As the coupling agent, a silane-based, titanate-based, aluminate-based, zircoaluminate-based, or other coupling agent can be used. Of these, a silane-based coupling agent is preferable. Examples of such silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminomethyl) -3-aminopropylmethyldimethoxysilane, and N- (2-aminoethyl) -3-amino. Propyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxy) Cyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like can be mentioned, which can be used alone or in combination. It is preferable that these silane-based coupling agents are previously immobilized on the surface of the filler by adsorption or reaction. Here, the treatment amount of the coupling agent with respect to 100 parts by mass of spherical silica is preferably 0.5 to 10 parts by mass.

The photosensitive resin composition may contain a colorant, if necessary. As the colorant, known colorants such as red, blue, green, and yellow can be used, and any of pigments, dyes, and pigments may be used, but halogens are used from the viewpoint of reducing the environmental load and having little effect on the human body. It is preferable that the colorant does not contain.

Examples of the red colorant include monoazo, disazo, azolake, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, quinacridone, etc. -Indexed (CI; issued by The Society of Dyersand Colorists).

Examples of monoazo red colorants include Pigment Red 1,2,3,4,5,6,8,9,12,14,15,16,17,21,22,23,31,32,112,114, 146,147,151,170,184,187,188,193,210,245,253,258,266,267,268,269 and the like can be mentioned. Examples of the disazo-based red colorant include Pigment Red 37, 38, 41 and the like. Further, as the monoazolake-based red colorant, Pigment Red 48: 1,48: 2,48: 3,48: 4,49: 1,49: 2,50: 1,52: 1,52: 2,53: 1,53: 2,57: 1,58: 4,63: 1,63: 2,64: 1,68 and the like can be mentioned. Examples of the benzimidazolone-based red colorant include Pigment Red 171 and 175, 176, 185 and 208. Examples of the perylene-based red colorant include Solvent Red 135, 179, Pigment Red 123, 149, 166, 178, 179, 190, 194, 224 and the like. Examples of the diketopyrrolopyrrole-based red colorant include Pigment Red 254, 255, 264, 270, and 272. Examples of the condensed azo-based red colorant include Pigment Red 220, 144, 166, 214, 220, 221, 242 and the like. Examples of the anthraquinone-based red colorant include Pigment Red 168, 177, 216 and Solvent Red 149, 150, 52, 207. Examples of the quinacridone-based red colorant include Pigment Red 122, 202, 206, 207, 209 and the like.

Examples of the blue colorant include phthalocyanine-based and anthraquinone-based compounds, and pigment-based compounds include compounds classified as Pigment. For example, Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15 :. 4,15: 6,16,60. As the dye system, Solvent Blue 35, 63, 68, 70, 83, 87, 94, 97, 122, 136, 67, 70 and the like can be used. In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

Examples of the yellow colorant include monoazo type, disazo type, condensed azo type, benzimidazolone type, isoindolinone type, anthraquinone type and the like. For example, the anthraquinone type yellow colorant includes Solvent Yellow 163, Pigment Yellow 24, 108, 193, 147, 199, 202 and the like can be mentioned. Examples of the isoindolinone-based yellow colorant include Pigment Yellow 110, 109, 139, 179, 185 and the like. Examples of the condensed azo-based yellow colorant include Pigment Yellow 93, 94, 95, 128, 155, 166, 180 and the like. Examples of the benzimidazolone-based yellow colorant include Pigment Yellow 120, 151, 154, 156, 175, 181 and the like. In addition, as a monoazo yellow colorant, Pigment Yellow 1,2,3,4,5,6,9,10,12,61,62,62: 1,65,73,74,75,97,100, 104, 105, 111, 116, 167, 168, 169, 182, 183 and the like can be mentioned. Examples of the disazo-based yellow colorant include Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, 198 and the like. Can be mentioned.

In addition, colorants such as purple, orange, brown, black, and white may be added. Specifically, Pigment Black 1,6,7,8,9,10,11,12,13,18,20,25,26,28,29,30,31,32, Pigment Violet 19, 23, 29 , 32, 36, 38, 42, Solvent Violet 13, 36, C.I. I. Pigment Orange 1,5,13,14,16,17,24,34,36,38,40,43,46,49,51,61,63,64,71,73, PigmentBrown 23,25, Carbon Black, Examples include titanium oxide.

The blending amount of the colorant in the photosensitive resin composition is not particularly limited, but is preferably 0.1 to 5% by mass based on the total amount of the photosensitive resin composition.

The photosensitive resin composition of the present invention may contain an organic solvent from the viewpoint of ease of preparation and coatability. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol and propylene glycol monomethyl ether. , Dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, tripropylene glycol monomethyl ether and other glycol ethers; ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbi Esters such as tall acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, and solvent naphtha are known. Conventional organic solvents can be used. These organic solvents may be used alone or in combination of two or more.

The blending amount of the organic solvent in the photosensitive resin composition can be appropriately changed according to the components constituting the photosensitive resin composition. For example, in terms of solid content, (A) with respect to 100 parts by mass of the carboxyl group-containing resin. It can be 30 to 300 parts by mass.

The photosensitive resin composition of the present invention may further contain an elastomer, a mercapto compound, a urethanization catalyst, a thixotropic agent, an adhesion accelerator, a block copolymer, a chain transfer agent, a polymerization inhibitor, and a copper damage inhibitor, if necessary. , Antioxidants, Anti-rust agents, Thickeners such as organic bentonite, montmorillonite, at least one of silicone-based, fluorine-based, polymer-based defoaming agents and leveling agents, phosphinates, phosphoric acid ester derivatives , A component such as a flame retardant such as a phosphorus compound such as a phosphazen compound can be blended. As these, those known in the field of electronic materials can be used.

The photosensitive resin composition of the present invention may be used as a dry film or may be used as a liquid. When used as a liquid, it may be one-component or two-component or more.

<Dry film>
In the present invention, the photosensitive resin composition may be in the form of a dry film including a support film and a resin layer composed of the photosensitive resin composition formed on the support film. Here, the support film in the present invention means a film that is adhered to at least a curable resin layer when laminated so that the resin layer side of the dry film is in contact with the base material. The support film may be peeled off from the curable resin layer in the step after laminating. In making a dry film, the photosensitive resin composition of the present invention is diluted with an organic solvent to adjust the viscosity to an appropriate level, and a comma coater, a blade coater, a lip coater, a rod coater, a squeeze coater, a reverse coater, a transfer coater, etc. A film can be obtained by applying a uniform thickness on a support film with a gravure coater, a spray coater or the like, and usually drying at a temperature of 50 to 130 ° C. for 1 to 30 minutes. The coating film thickness is not particularly limited, but is generally selected as appropriate in the range of 1 to 150 μm, preferably 10 to 60 μm after drying.

As the support film, any known one can be used without particular limitation. For example, a polyester film such as polyethylene terephthalate or polyethylene naphthalate, a polyimide film, a polyamideimide film, a polypropylene film, a thermoplastic resin such as a polystyrene film, etc. can be used. A film made of the above can be preferably used. Among these, a polyester film is preferable from the viewpoint of heat resistance, mechanical strength, handleability and the like. Further, the laminate of these films can also be used as a support film.

Further, the thermoplastic resin film as described above is preferably a film stretched in the uniaxial direction or the biaxial direction from the viewpoint of improving the mechanical strength.

The thickness of the support film is not particularly limited, but can be, for example, 10 μm to 150 μm.

After forming the resin layer of the photosensitive resin composition of the present invention on the support film, the cover can be peeled off from the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. ) It is preferable to laminate the film. Here, the protective film in the present invention means a film that is peeled off from the resin layer before laminating when the dry film is laminated on the base material so as to be in contact with the resin layer side and integrally molded. As the peelable protective film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a surface-treated paper, or the like can be used, and when the protective film is peeled off, the adhesive strength between the resin layer and the support film is increased. However, the adhesive strength between the resin layer and the protective film may be smaller.

The thickness of the protective film is not particularly limited, but can be, for example, 10 μm to 150 μm.

The above-mentioned photosensitive resin composition is adjusted to a viscosity suitable for the coating method using the above-mentioned organic solvent, and a dip coating method, a flow coating method, a roll coating method, a bar coater method, and a screen printing method are applied onto the substrate. After coating by a method such as a curtain coat method, the organic solvent contained in the composition is volatilized and dried (temporarily dried) at a temperature of 60 to 100 ° C. to form a tack-free resin layer. When the photosensitive resin composition contains an organic solvent, it is preferable to apply the photosensitive resin composition and then volatilize and dry it. Volatile drying can be performed by using a hot air circulation type drying oven, IR furnace, hot plate, convection oven, etc. It can be done by using the spraying method).

On the other hand, when a dry film is used, the dry film is attached onto the substrate by a laminator or the like so that the resin layer comes into contact with the substrate, and then the support film is peeled off either before or after the exposure step described later. As a result, a resin layer is formed on the base material. When using a dry film provided with a protective film, the protective film is peeled off from the dry film and then bonded to the base material. It is preferable that the dry film is attached to the substrate under pressure and heating using a vacuum laminator or the like. By using such a vacuum laminator, when a circuit-formed substrate is used, even if the surface of the circuit board is uneven, the dry film adheres to the circuit board, so that there is no air bubbles mixed in and the circuit board is not mixed. The hole filling property of the recess on the surface of the substrate is also improved. The pressurizing condition is preferably about 0.1 to 2.0 MPa, and the heating condition is preferably 40 to 120 ° C.

A dry coating film of the photosensitive resin composition is formed on the substrate, or a resin layer is formed using a dry film, and then selectively exposed to active energy rays through a photomask having a predetermined pattern. The exposed portion is developed with a dilute alkaline aqueous solution (for example, 0.3 to 3 mass% sodium carbonate aqueous solution) to form a pattern of the cured product. In the case of a dry film, after exposure, the support film is peeled off from the dry film and developed to form a patterned cured product on the substrate. The exposed resin layer may be exposed and developed by peeling the support film from the dry film before exposure as long as the characteristics are not impaired.

Further, in the present invention, at least one of heating and ultraviolet irradiation may be performed on the developed resin layer after the above-mentioned exposure and development and before irradiation with the active energy rays described later. For example, the resin layer formed by exposure and development is heat-cured (100 to 220 ° C.) or irradiated with light, or is finally finished-cured (mainly cured) by combined use of heat-curing and light irradiation to achieve adhesion and hardness. It forms a cured film with excellent various properties such as. According to the method of the present invention, even such a cured film having increased adhesion to the substrate can be easily removed by a solvent.

The exposure machine used for the above-mentioned active energy ray irradiation may be a device equipped with a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, etc., and irradiates ultraviolet rays in the range of 350 to 450 nm. Further, a direct drawing device (for example, a laser direct imaging device that directly draws an image with a laser based on CAD data from a computer) can also be used. The lamp light source or the laser light source of the direct drawing machine may have a maximum wavelength in the range of 350 to 450 nm. The amount of exposure for image formation varies depending on the film thickness and the like, but is generally 10 to 1000 mJ / cm ² , preferably 20 to 800 mJ / cm ² . The active energy ray here is at least one of an active energy ray capable of generating active oxygen in the presence of oxygen and an active energy ray capable of cleaving a CC carbon bond, which will be described later, from the viewpoint of wavelength. Can be distinguished. The presence of oxygen means that the oxygen flow rate in the atmosphere is at least 0.2 sccm or more, and is generally 0.5 sccm or more.

The developing method can be a dipping method, a shower method, a spray method, a brush method, etc., and the developing solution includes potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, and ammonia. , Alkaline solutions such as amines can be used.

The thickness of the cured film to be formed may be appropriately set depending on the intended use of the wiring board, but is preferably in the range of 1 to 1000 μm. If the cured film is too thick, it may take time to remove the cured film described later. Further, the method of confirming whether or not the cured film is formed can be confirmed by the following method. That is, in an environment of 25 ° C. and 50% RH, a waste cloth containing isopropyl alcohol (IPA) is placed on the surface of the cured film, and a weight of 500 g is placed on the waste cloth and allowed to stand for 1 minute, and then the waste cloth is placed. Is peeled off, and the state in which all or part of the resin layer is not attached to the surface in contact with the cured film of the waste cloth is judged to be the "cured state".

The cured film formed on the substrate as described above is in close contact with the substrate. The degree of adhesion between the substrate and the cured film depends on the surface condition of the substrate on which the cured film is provided, the composition of the photosensitive resin composition, and the curing conditions, but the copper-clad laminate test of JIS-C-6481 The peel strength measured according to the method and the measuring method of peel strength (test piece width 10 mm, 90 ° direction, speed 50 mm / min) is preferably 3 N / cm or more, and preferably 5 N / cm or more. Is more preferable. The upper limit is preferably 10 N / cm or less. According to the method of the present invention, the cured film can be easily removed by the solvent even when the adhesion between the substrate and the cured film is high.

[Irradiation process of active energy rays]
In some cases, the cured film obtained as described above may have a problem. For example, printing defects when a photosensitive resin composition such as solder resist ink is applied to a substrate, misalignment during exposure, color unevenness (color unevenness), pinholes in a dry coating film, contamination with foreign matter, marking ink. Problems such as printing defects may occur. Even in such a case, according to the method of the present invention, the cured film can be peeled off from the base material only at a defective portion, and the base material can be reused.

The active energy ray used in the present invention is at least one of an active energy ray capable of generating active oxygen in the presence of oxygen and an active energy ray capable of cleaving a CC carbon bond, and has a wavelength of 100 to 255 nm. Ionizing radiation can be preferably used. When ionizing radiation having a wavelength of 100 to 255 nm is irradiated in the presence of oxygen, some of the oxygen molecules in the atmosphere become active oxygen (including ozone). The active oxygen cleaves the CC carbon bonds of the polymer chains that make up the cured product. As a result, some of the cleaved hydrocarbon radicals combine with oxygen to become carbon dioxide and the like and vaporize. In addition, hydrocarbon radicals may recombine to form low molecular weight compounds, and some of these low molecular weight compounds are vaporized. Further, since the ionizing radiation having a wavelength of 100 to 255 nm is an ionizing radiation having an energy higher than the CC carbon bond energy, the polymer chain constituting the cured film can be cut to reduce the molecular weight. As a result, the residue remaining on the substrate (hydrocarbon remaining without vaporization, etc.) can be easily removed with a solvent or the like.

Devices that can irradiate ionizing radiation with a wavelength of 100 to 255 nm include, for example, UV ozone cleaner (distance from UV lamp light source to irradiation surface is 1 cm, type: low pressure mercury lamp (fused quartz), shape: high density high output grid type. Devices such as lamps and ultraviolet intensity: 28 mW / cm ² ) can be mentioned. When the ionizing radiation is ultraviolet rays, the intensity thereof is preferably 3 to ^{50 mW / cm 2.}

[Curing film removal process]
Next, the base material on which the cured film is formed is washed with a solvent to remove the cured film of the portion irradiated with the active energy ray from the base material. As a method for cleaning the cured film on the substrate, a dipping method, a spraying method, a method using a single-wafer method, or the like can be used. In particular, when removing the cured film only at a defective portion, a spraying method or the like is suitable.

As the solvent, various organic solvents can be used, and among them, an aprotic polar solvent can be preferably used in consideration of the influence on the manufactured wiring board. Examples of the aprotonic polar solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, and dimethylpropylene. Examples thereof include urea, dimethyl sulfoxide, γ-butyrolactone, β-propiolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, and these can be used alone or in combination of two or more. .. Among these, N-methylpyrrolidone can be preferably used.

Even when the residue on the upper surface of the substrate is washed with a solvent, a very small amount of the residue may remain on the substrate. Therefore, in the method of the present invention, the wiring board from which the cured film has been removed is heated. It is preferable to do so. The heating temperature is preferably in the range of 80 to 200 ° C, more preferably in the range of 100 to 150 ° C.

The method of the present invention can be used in the manufacture of electronic components such as printed wiring boards. Since the cured film can be removed from the base material regardless of the composition of the photosensitive resin composition, it is particularly useful when a high value-added base material is used. In addition, since the active energy rays can be irradiated only to the defective part of the cured film, if a defect is found in a part of the cured film during manufacturing of the wiring board, only the defective part is the cured film. Can be removed from the base material, and production efficiency (yield) can be improved.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following, "part" and "%" are all based on mass unless otherwise specified.

[Prepared into a photosensitive resin composition]
First, a photosensitive resin composition was prepared. The photosensitive resin composition contains 13 parts (value as solid content) of the following carboxyl group-containing resin varnish 1 and 30 parts (value as solid content) of the following carboxyl group-containing resin varnish 2 as a photopolymerization initiator. 4 parts of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Omnirad TPO H, manufactured by IGM Resins), tricyclodecanedimethanol diacrylate (A-DCP, manufactured by Shin-Nakamura Kogyo Co., Ltd.) as a photopolymerizable monomer. 11 parts, bisphenol A type epoxy resin (jER 828, manufactured by Mitsubishi Chemical Co., Ltd.) as a thermosetting component, and imidazole epoxy resin curing agent (Curesol 1B2PZ, manufactured by Shikoku Kasei Co., Ltd.) as a thermosetting catalyst. 0.3 parts were mixed, premixed with a stirrer, and then kneaded with a three-roll mill to prepare a photosensitive resin composition.

<Carboxyl group-containing resin varnish 1>
A novolak type cresol resin (manufactured by Aika Kogyo Co., Ltd., trade name "Shonol CRG951", OH equivalent: 119.4) 119.4 g, in an autoclave equipped with a thermometer, a nitrogen introduction device and an alkylene oxide introduction device, and a stirring device. 1.19 g of potassium hydroxide and 119.4 g of toluene were charged, the inside of the system was replaced with nitrogen while stirring, and the temperature was raised by heating. Next, 63.8 g of propylene oxide was gradually added dropwise, and the mixture was reacted at ^{125-132 ° C. and 0 to 4.8 kg / cm 2 for 16 hours.} Then, it was cooled to room temperature, and 1.56 g of 89% phosphoric acid was added to and mixed with this reaction solution to neutralize potassium hydroxide, the non-volatile content was 62.1%, and the hydroxyl value was 182.2 g / eq. A propylene oxide reaction solution of the novolak type cresol resin was obtained. This had an average of 1.08 mol of alkylene oxide added per equivalent amount of phenolic hydroxyl group. Next, 293.0 g of an alkylene oxide reaction solution of the obtained novolak-type cresol resin, 43.2 g of acrylic acid, 11.53 g of methanesulfonic acid, 0.18 g of methylhydroquinone and 252.9 g of toluene were added to a stirrer, a thermometer and air. It was charged into a reactor equipped with a blow tube, air was blown at a rate of 10 ml / min, and the reaction was carried out at 110 ° C. for 12 hours with stirring. As the water produced by the reaction, 12.6 g of water was distilled off as an azeotropic mixture with toluene. Then, the mixture was cooled to room temperature, the obtained reaction solution was neutralized with 35.35 g of a 15% aqueous sodium hydroxide solution, and then washed with water. Then, toluene was distilled off while substituting 118.1 g of diethylene glycol monoethyl ether acetate with an evaporator to obtain a novolak type acrylate resin solution. Next, 332.5 g of the obtained novolak-type acrylate resin solution and 1.22 g of triphenylphosphine were charged into a reactor equipped with a stirrer, a thermometer and an air blowing tube, and air was blown at a rate of 10 ml / min. , 60.8 g of tetrahydrophthalic anhydride was gradually added with stirring, and the mixture was reacted at 95 to 101 ° C. for 6 hours. In this way, a resin solution of a carboxyl group-containing photosensitive resin having a solid acid value of 88 mgKOH / g, a solid content of 71%, and a weight average molecular weight of 2,000 was obtained. This is referred to as a carboxyl group-containing resin varnish 1.

<Carboxyl group-containing resin varnish 2>
In a flask equipped with a stirrer, a thermometer and a condenser, 848.8 g of γ-butyrolactone, 57.5 g (0.23 mol) of MDI (diphenylmethane diisocyanate), and DMBPDI (4,4'-diisocyanate-3,3'-dimethyl). -1,1'-biphenyl) 59.4 g (0.225 mol), TMA (anhydrous trimellitic acid) 67.2 g (0.35 mol) and TMA-H (cyclohexane-1,3,4-tricarboxylic acid- Add 29.7 g (0.15 mol) of 3,4-anhydride), raise the temperature to 80 ° C while paying attention to heat generation while stirring, dissolve and react at this temperature for 1 hour, and then react for another 2 hours. After raising the temperature to 160 ° C., the reaction was carried out at this temperature for 5 hours. The reaction proceeded with the foaming of carbon dioxide gas, and the inside of the system became a brown transparent liquid. In this way, a solution of a carboxyl group-containing amidimide resin having a viscosity of 7 Pa · s at 25 ° C. and a solid content of 17% and a solution acid value of 5.3 (KOHmg / g) (resin dissolved in γ-butyrolactone). Composition) was obtained. The solid acid value of the resin was 31.2 (KOHmg / g), and the weight average molecular weight was 34,000. This is referred to as a carboxyl group-containing resin varnish 2.

FR-4 copper-clad laminate (100 mm x 150 mm x 0.8 mmt, double-sided copper foil, copper foil thickness is 18 μm on both sides) Arithmetic average surface roughness (Ra) is 400 nm by CZ8101 manufactured by MEC Co., Ltd. The photosensitive resin composition obtained as described above was entirely applied to the chemically polished surface of the substrate by screen printing so that the film thickness after drying was 20 to 25 μm. It was dried at 80 ° C. for 30 minutes and allowed to cool to room temperature.

Next, on the coating film, L / S = 100/100, 80/80, 60/60, 40/40, 20/20, 10/10, 7/7, 5/5, 4/4, 3/3, Using a metal halide lamp through a photomask in which a line pattern of 2/2 and 1/1 (both units are μm) is formed ^{, ultraviolet rays with an exposure of 1,000 mJ / cm 2} and a wavelength of 365 nm are emitted under an atmospheric atmosphere. Then, development was carried out for 180 seconds using a 1 wt% Na ₂ CO _{3 aqueous solution at 30 ° C. to form a cured film.} Whether or not the cured film was formed was determined by placing a waste cloth containing isopropyl alcohol (IPA) on the surface of the cured film in an environment of 25 ° C. and 50% RH, and then placing a 500 g weight on the waste cloth for 1 minute. After allowing to stand, the waste cloth was peeled off, and it was judged that all or part of the resin layer did not adhere to the surface in contact with the cured film of the waste cloth. Further, in the formed cured film, the peel strength measured in accordance with the JIS-C-6481 copper-clad laminated plate test method and the peel strength measuring method (test piece width 10 mm, 90 ° direction, speed 50 mm / min). Was confirmed to be 3 N / cm or more and 10 N / cm or less.

[Example 1]
Two substrates on which the cured coating obtained as described above was formed were prepared. On the other hand, for the cured film-forming substrate, the entire surface of the cured film-forming surface is covered with a UV ozone cleaner (the distance from the UV lamp light source to the irradiation surface is 1 cm, type: low-pressure mercury lamp (fused quartz), shape: high-density and high output. Using a grid lamp, ultraviolet intensity: 28 mW / cm ² ), an active energy ray with a wavelength of 185 nm (10%) + 254 nm (90%) in the presence of oxygen (oxygen flow rate is 0) at an exposure rate of 25.2 J / cm ^2. It was irradiated under an atmospheric atmosphere of .5 sccm).
The other cured film-forming substrate was irradiated with active energy rays under the same conditions as described above via a light-shielding mask so that only the portion where the line pattern was formed by the photomask was irradiated.
Subsequently, for the cured film-forming substrate that was completely irradiated, the substrate was immersed in an N-methylpyrrolidone solvent, left at 55 ° C. for 20 minutes, and then the solvent was removed. For the partially irradiated cured film-forming substrate, the N-methylpyrrolidone solvent was dropped onto the active energy ray-irradiated portion of the substrate, left at 55 ° C. for 20 minutes, and then the solvent was removed.
When the obtained substrate was visually confirmed, the cured film at the portion irradiated with the active energy ray was completely removed from all the substrates.

[Comparative Example 1]
Each of the two cured film-forming substrates was treated with an N-methylpyrrolidone solvent in the same manner as in Example 1 except that the low-pressure mercury lamp was not used to irradiate the active energy rays. When the obtained substrate was visually confirmed, the cured film did not peel off from the substrate in any of the substrates.

[Comparative Example 2]
N-methyl was applied to each of the two cured film-forming substrates in the same manner as in Example 1 except that the irradiation of the active energy rays by the low-pressure mercury lamp was changed from the presence of oxygen (atmosphere) to the atmosphere of nitrogen. The treatment was carried out using a pyrrolidone solvent. When the obtained substrate was visually confirmed, in any of the substrates, the cured coating on the portion irradiated with the active energy ray was partially peeled off from the substrate, but was not completely peeled off from the substrate, and the cured coating was not completely peeled off. Remained.
From the experimental results of Example 1 and Comparative Examples 1 and 2, it can be seen that the cured film can be effectively peeled off by irradiating with active energy rays in the presence of oxygen.

[Comparative Example 3]
Examples except for irradiating active energy rays (main wavelength 365 nm) from a low-pressure mercury lamp to a UV conveyor using a high-pressure mercury lamp (ORC Manufacturing Co., Ltd. model: QRM-2082, ultraviolet intensity: 80 mW / cm ^2). In the same manner as in No. 1, each of the two cured film-forming substrates was treated with an N-methylpyrrolidone solvent. When the obtained substrate was visually confirmed, in any of the substrates, the cured coating on the portion irradiated with the active energy ray was partially peeled off from the substrate, but was not completely peeled off from the substrate, and the cured coating was not completely peeled off. Remained.
From the experimental results of Example 1 and Comparative Example 3, it can be seen that active oxygen was not generated and the CC carbon bond was not broken by the ultraviolet irradiation using the high-pressure mercury lamp.

Claims (7)

A method of removing a part or all of the cured coating from a wiring board having a cured coating formed on the surface of the substrate and reusing the substrate.
The cured film is made of a cured product of a photosensitive resin composition.
A step of irradiating a part or all of the cured film with at least one of an active energy ray capable of generating active oxygen in the presence of oxygen and an active energy ray capable of cleaving a CC carbon bond.
A step of washing the base material on which the cured film is formed with a solvent and removing the cured film of the portion irradiated with the active energy ray from the base material.
The will Nde including,
A method for reusing a base material for a wiring board, wherein the solvent is an aprotic polar solvent. The cured film is formed by applying a photosensitive resin composition on the substrate and drying to form a dry coating film, or applying a photosensitive resin composition to a support film and drying to form a resin layer. The dry film is formed by laminating the dry film so that the base material and the resin layer are in contact with each other, and then exposing, developing, and patterning the dry coating film or the resin layer of the dry film. The method according to claim 1. The method according to claim 1 or 2, wherein the active energy ray comprises ionizing radiation having a wavelength of 100 to 255 nm. The method according to any one of claims 1 to 3, further comprising a step of heating the wiring board from which the cured film has been removed. Any of claims 1 to 4 , wherein the photosensitive resin composition contains (A) a carboxyl group-containing resin, (B) a photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting component. The method described in item 1. The method according to claim 5 , wherein at least one of heating and ultraviolet irradiation is performed after the exposure and development of the resin layer and before the irradiation of the cured film with active energy rays. The method according to any one of claims 1 to 6 , wherein the cured film has a thickness of 1 to 1000 μm.