JP2021124568A - Photosensitive resin laminate and resist pattern formation method - Google Patents

Abstract

To provide a photosensitive resin laminate which can cope with fining of a pattern, facilitates resist peeling even in a resist pattern having a narrow pitch, and can stably hold a resist pattern having fine lines and dots onto a base material, and a resist pattern formation method.SOLUTION: A photosensitive resin composition is obtained by laminating at least (A) a support film, (B) a peeling layer and (C) a photosensitive resin layer in this order, in which the (B) peeling layer contains polyvinyl alcohol having a saponification degree of 86.0 mol% or less and a polymerization degree of 900 or less, and the (C) photosensitive resin layer contains (C1) an alkali-soluble resin, (C2) a photopolymerization initiator and (C3) an acrylate monomer, and contains ethylene oxide-modified pentaerythritol tetraacrylate as the (C3) acrylate monomer.SELECTED DRAWING: Figure 1

Description

The present invention relates to a photosensitive resin laminate and a method for forming a resist pattern using the photosensitive resin laminate.

In recent years, with the miniaturization and weight reduction of electronic devices, miniaturization of patterns in printed wiring boards, metal masks, and the like has been promoted. Therefore, in the production of a conductor circuit or a metal mask of a printed wiring board, a metal layer is produced by a (semi) additive method using a photosensitive resin composition and electrolytic plating.

For example, in the (semi) additive method for printed wiring boards, a thin electroless plating layer is first formed on the surface of an insulating resin such as glass epoxy resin by electroless plating, and then a photosensitive resin composition is formed on the surface of the electroless plating layer. After forming a photosensitive resin layer containing This is a method of etching a plating layer (for example, Patent Document 1).

Further, for example, as a method for producing a metal mask, a first step of forming a photosensitive resin layer containing a photosensitive resin composition having a predetermined thickness on a substrate and an opening of the metal mask on the photosensitive resin layer The second step of pattern exposure according to the above, the third step of developing and removing only the unexposed portion of the photosensitive resin layer to create a resist pattern, and exposing the substrate, and the substrate obtained by this third step. After performing the fourth step of forming the metal mask material layer by electrolytic plating on the exposed portion, the fifth step of removing the residual photosensitive resin layer and the sixth step of separating the metal mask material layer from the substrate are performed. There is a method for producing (for example, Patent Document 2).

In the production of a conductor circuit or a metal mask of a printed wiring board, a photosensitive resin laminate containing a support film and a photosensitive resin layer is used to form a resist pattern. The method of using the photosensitive resin laminate is to attach the photosensitive resin laminate by a laminating method so that the photosensitive resin layer is in contact with at least one surface of the base material, and then attach the photosensitive resin laminate to the support film. The desired pattern is exposed through the process, then the support film is removed, and then the developing is performed by removing the unnecessary photosensitive resin layer with a developing solution to form a resist pattern. At the time of exposure, the exposure is performed through the support film, but the scattering of light from the support film makes it difficult to expose a fine pattern. Therefore, it is necessary to make the thickness of the support film as thin as possible. On the other hand, in order to coat the photosensitive resin layer, mechanical strength is required for the support film, and generally a thickness of about 15 μm to 38 μm is required, which can meet the demand for pattern miniaturization. could not.

In order to solve such an exposure problem, it has been studied to remove the support film from the photosensitive resin laminate and then directly expose the photomask on the photosensitive resin layer. However, the photomask and the photosensitive resin layer were in close contact with each other, and the photomask could not be easily peeled off. Further, by forcibly peeling off the photomask, the photomask may be contaminated by the photosensitive resin layer. Further, since the exposure is performed without the support film, there is a problem that the polymerization is inhibited by oxygen and the photopolymerization reaction of the photosensitive resin layer becomes insufficient. Therefore, a photosensitive resin laminate in which a support film, a release layer, and a photosensitive resin layer are laminated in this order has been proposed. That is, after removing the support film, the photomask can be directly brought into close contact with the release layer for exposure, and the demand for miniaturization of the pattern can be met (for example, Patent Documents 3 and 4).

On the other hand, in the production of a metal layer using electrolytic plating, a resist pattern having a narrow pitch is formed, and electrolytic plating is applied to the narrow space to form a thick metal layer to be an electrolytic plating layer or a metal mask material layer. However, in the subsequent step of peeling the resist pattern, there is a problem that the resist pattern is not peeled normally and the resist stripped piece remains on the printed wiring board or the metal mask.

In order to solve such a problem of resist peeling, a photosensitive resin composition that dissolves in a resist stripping liquid has been proposed (see, for example, Patent Documents 5 to 8). If the solubility in the resist stripping solution is good, the problem that the resist stripping piece remains in a narrow space can be eliminated. In Patent Documents 5 to 8, a photosensitive resin composition in which the content of methacrylate monomer is reduced and the content of acrylate monomer is increased as a crosslinkable monomer in order to enhance the solubility of the photosensitive resin composition in a resist stripping solution. Things have been proposed. However, when the content of the acrylate monomer is increased, the hydrophilicity of the photosensitive resin composition is high, so that the photosensitive resin layer swells during alkaline development, and as a result, the resist pattern is formed and the plating process is fine. There is a problem that lines and dots are easily peeled off from the substrate. Therefore, a photosensitive resin composition in which a resist pattern having fine lines and dots while having a property of being dissolved in a resist stripping liquid is stably retained on a substrate in a resist pattern forming and plating step is obtained. It is desired.

Japanese Unexamined Patent Publication No. 2004-101617 Japanese Unexamined Patent Publication No. 4-166844 Japanese Unexamined Patent Publication No. 4-371957 Japanese Unexamined Patent Publication No. 6-242611 Japanese Unexamined Patent Publication No. 9-265180 JP-A-2010-113349 Japanese Unexamined Patent Publication No. 2011-81031 Japanese Unexamined Patent Publication No. 2013-37272

An object of the present invention is that the resist pattern can be made finer, the resist can be easily peeled off even in a resist pattern having a narrow pitch, and the resist pattern having fine lines and dots is stably held on the substrate. It is to provide a sex resin laminate and a resist pattern forming method.

The above problem was solved by the following means.
<1>
At least (A) a support film, (B) a release layer, and (C) a photosensitive resin layer are laminated in this order, and (B) the release layer has a saponification degree of 86.0 mol% or less and a degree of polymerization of 900. The following polyvinyl alcohol is contained, and the (C) photosensitive resin layer contains (C1) an alkali-soluble resin, (C2) a photopolymerization initiator and (C3) an acrylate monomer, and is used as a (C3) acrylate monomer. (C3a) A photosensitive resin laminate comprising ethylene oxide-modified pentaerythritol tetraacrylate (a compound represented by the general formula (i) and having l + m + n + o = 24-48).

<2>
The photosensitive resin laminate according to <1> above is attached by a laminating method so that the (C) photosensitive resin layer is in contact with at least one surface of the base material, then (A) the support film is removed, and then A method for forming a resist pattern, which comprises exposing a desired pattern and then developing (C) a photosensitive resin layer at the same time as removing (B) a release layer with a developing solution.

The photosensitive resin laminate and the resist pattern forming method of the present invention can cope with the miniaturization of the pattern, the resist can be easily peeled off even in the resist pattern having a narrow pitch, and the resist pattern having fine lines and dots is used as the base material. The effect of being stably held on top can be achieved.

It is sectional drawing of the photosensitive resin laminated body of this invention.

Hereinafter, the photosensitive resin laminate and the resist pattern forming method of the present invention will be described in detail.

As the (A) support film, (A) a release layer can be formed on the support film, (B) a photosensitive resin layer can be formed on the (B) release layer, and the photosensitive resin is laminated. Any film may be used as long as the (A) support film can be peeled off from the base material after the body is attached to the base material by a laminating method. It may be a transparent film that transmits light, or a white film or a colored film that blocks light. For example, polyolefins such as polypropylene and polyethylene; polyimide; polyester films such as polyethylene naphthalate, polyethylene terephthalate and flame-retardant polyethylene terephthalate; films such as polycarbonate, polyphenylene sulfide, polyetherimide, modified polyphenylene ether and polyurethane can be used. Among them, the use of polyethylene terephthalate film is advantageous in terms of laminating suitability, peeling suitability, and smoothness, and also has advantages such as low cost, non-embrittlement, excellent solvent resistance, and high tensile strength. Therefore, it is very easy to use. The thickness of the support film (A) is preferably 1 to 100 μm, more preferably 12 to 50 μm.

In the present invention, the (B) release layer contains polyvinyl alcohol having a saponification degree of 86.0 mol% or less and a polymerization degree of 900 or less. The (B) release layer can be formed by applying a polyvinyl alcohol aqueous solution, which is a coating solution for the release layer, onto the (A) support film.

In the present invention, the (B) release layer has a property that the (C) photosensitive resin layer can be uniformly and uniformly formed on the (B) release layer. Further, the adhesion between the support film (A) and the release layer (B) is excellent, and the adhesion between the release layer (B) and the photosensitive resin layer (C) is also excellent.

(B) When the saponification degree of polyvinyl alcohol contained in the release layer is more than 86.0 mol%, air bubbles are likely to enter the polyvinyl alcohol aqueous solution. Therefore, when the support film is coated with (A), the air bubbles cause pins. A hole is generated. In addition, the viscosity of the polyvinyl alcohol aqueous solution becomes high, coating streaks occur, and the thickness variation becomes large. In addition, bubbles are generated in the developing solution, which causes a problem that the developing solution overflows from the developing tank. Further, the adhesion between the support film (A) and the peeling layer (B) is weakened, and there arises a problem that the peeling layer is peeled off when the film is bent by handling. When the saponification degree is 86.0 mol% or less, a good (B) release layer can be formed, there is no problem in the running property of the developing solution, and (A) the support film and (B) the release layer are separated. The adhesive strength of the film is high, and even if it is bent by handling, the (C) photosensitive resin layer is unlikely to be peeled off. A more preferable degree of saponification is 84.0 mol% or less, and a more preferable degree of saponification is 75.0 mol% or less. The saponification degree is preferably 69.0 mol% or more.

Similarly, when the degree of polymerization of polyvinyl alcohol contained in (B) the release layer exceeds 900, air bubbles are likely to enter when the polyvinyl alcohol aqueous solution is used, and therefore, when coating the support film (A), Pinholes are generated by the bubbles. In addition, the viscosity of the polyvinyl alcohol aqueous solution becomes high, coating streaks occur, and the variation in film thickness becomes large. Further, (C) bubbles are generated in the alkaline developer for the photosensitive resin layer, which causes a problem that the alkaline developer overflows from the developing tank, and (A) the support film and (B) the peeling interlayer are formed. The adhesiveness of the film is weakened, and there is a problem that the peeling layer (B) is peeled off when the film is bent during handling. When the degree of polymerization is 900 or less, a good (B) release layer can be formed, there is no problem in the running property of the alkaline developer, and there is no problem between the (A) support film and the (B) release layer. The adhesion is high, and even if it is bent by handling, the (C) photosensitive resin layer is unlikely to be peeled off. A more preferable degree of polymerization is 600 or less, and a more preferable degree of polymerization is 400 or less. The degree of polymerization is preferably 200 or more. For example, examples of the polyvinyl alcohol contained in the (B) release layer include Kuraray Co., Ltd., Kuraray Poval 3-80, 5-74, 5-82 and the like.

In the (B) peeling layer, the content of polyvinyl alcohol is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, based on the total non-volatile content of the (B) peeling layer. It is more preferably 95 to 100% by mass. When the content is less than 80% by mass, oxygen in the air permeates the (B) peeling layer, oxygen inhibition of radical polymerization occurs, and (C) the photocuring of the photosensitive resin layer becomes insufficient. In some cases. The above-mentioned "total non-volatile mass" means (B) when the coating liquid for the release layer is applied onto the (A) support film and sufficiently dried to form the (B) release layer. It refers to the mass of the entire release layer.

(B) When the content of polyvinyl alcohol having a saponification degree of 86.0 mol% or less and a degree of polymerization of 900 or less is less than 100% by mass in the release layer, the remaining components are not particularly limited, but plastic. Examples thereof include low molecular weight compounds such as agents and high molecular weight compounds. Examples of these compounds include polyethylene glycol, polypropylene glycol, poly (meth) acrylic acid, poly (meth) acrylic acid ester, carboxymethyl cellulose (CMC), sardine, casein, sodium alginate, vinyl acetate resin, polyvinylpyrrolidone, and poly. Examples thereof include water-soluble resins such as acryloylmorpholine. Further, polyvinyl alcohol having a saponification degree of more than 86.0 mol% or polyvinyl alcohol having a degree of polymerization of more than 900 can be mentioned.

(B) The thickness of the release layer is preferably 0.5 to 10 μm, more preferably 1 to 5 μm. If it is thinner than 0.5 μm, problems such as film thickness unevenness and pinholes may easily occur when the film is formed. If it is thicker than 10 μm, light is scattered during exposure, and the line width of the resist pattern of the (C) photosensitive resin layer becomes thicker, which may make it impossible to cope with the miniaturization of the pattern and deteriorate the resolution. (B) The thickness of the release layer is the thickness after drying.

The (C) photosensitive resin layer of the present invention contains (C1) an alkali-soluble resin, (C2) a photopolymerization initiator and (C3) an acrylate monomer, and (C3a) ethylene oxide-modified pentaerythritol as an (C3) acrylate monomer. It is characterized by containing a tetraacrylate (a compound represented by the general formula (i) and having l + m + n + o = 24-48).

L, m, n, and o in the general formula (i) are all repeating units in the general formula (i), and all are natural numbers.

In the (C1) alkali-soluble resin in the present invention, "alkali-soluble" means that when the target resin is coated and immersed in a 1% by mass sodium carbonate aqueous solution at 25 ° C. for 10 minutes, the film thickness is 0.01 μm or more. Says something that dissolves. Specific examples of the (C1) alkali-soluble resin include resins containing an acidic group and having an acid value of 40 mgKOH / g or more. Specific examples of the acidic group include a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group, and a phosphoric acid group.

Examples of the (C1) alkali-soluble resin include organic polymers such as (meth) acrylic resin, styrene resin, epoxy resin, amide resin, amide epoxy resin, alkyd resin, and phenol resin. .. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Among them, it is preferable to use a (meth) acrylic resin. As the (meth) acrylic resin, a (meth) acrylic polymer obtained by mainly using (meth) acrylate and copolymerizing it with an ethylenically unsaturated carboxylic acid is preferable. Further, this may be obtained by copolymerizing another monomer having a copolymerizable ethylenically unsaturated group.

Examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) acrylate. n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, glycidyl (meth) Acrylate, lauryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2- (dimethylamino) ethyl (meth) acrylate, 2- (diethylamino) ethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) ) Acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate and the like.

When "(meth) acrylic", "(meth) acrylate" and the like are described, they mean "acrylic or methacrylic", "acrylate or methacrylate" and the like, respectively.

As the ethylenically unsaturated carboxylic acid, monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid are preferably used, and dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid, and anhydrides and half esters thereof can be used. It can also be used. Of these, acrylic acid and methacrylic acid are particularly preferable.

Examples of the other monomer having a copolymerizable ethylenically unsaturated group include styrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, p-methoxystyrene, p-ethoxystyrene and p-chloro. Examples thereof include styrene, p-bromostyrene, (meth) acrylonitrile, (meth) acrylamide, diacetone acrylamide, vinyl toluene, vinyl acetate, vinyl-n-butyl ether and the like.

The acid value of the (C1) alkali-soluble resin affects the alkali development speed, resist peeling speed, exposure sensitivity, (C) softness of the photosensitive resin layer, adhesion between the photosensitive resin layer and the substrate, and the like. The acid value of the alkali-soluble resin (C1) is preferably 40 to 500 mgKOH / g, more preferably 100 to 300 mgKOH / g. If the acid value is less than 40 mgKOH / g, the developing time tends to be long, while if it exceeds 500 mgKOH / g, the adhesion between the (C) photosensitive resin layer and the substrate may deteriorate. The acid value is a value measured in accordance with JIS K2501: 2003.

The mass average molecular weight of the (C1) alkali-soluble resin is preferably 5,000 to 150,000, and more preferably 10,000 to 100,000. If the mass average molecular weight of the (C1) alkali-soluble resin is less than 5,000, it may be difficult to form the (C) photosensitive resin layer before curing in a film state. On the other hand, when the mass average molecular weight of the (C1) alkali-soluble resin exceeds 150,000, the solubility in a developing solution tends to deteriorate and the rate of dissolution in a resist stripping solution tends to slow down.

(C2) Examples of the photopolymerization initiator include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane-1-one and 2-methyl-1- [4- (methylthio) phenyl] -2. Aromatic ketones such as −morpholino-propane-1-one; 2-ethylanthraquinone, phenanthrenquinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenyl Anthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone Kinones such as; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether; benzoin compounds such as benzoin, methyl benzoin, ethyl benzoin; benzyl dimethyl ketal, 1-hydroxy-cyclohexyl-phenyl-ketone, 2- Hydroxy-2-methyl-1-phenyl-propane-1-one, 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-propan-1-one, 2- (dimethylamino) -2-[(4-methyl) Alkylphenones such as [Phenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone; 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6- Acylphosphine oxides such as trimethylbenzoyl) -phenylphosphine oxide; 1,2-octanedione, 1- [4- (phenylthio)-, 2- (o-benzoyloxime)], ethanone, 1- [9- Oxim esters such as ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl]-, 1- (o-acetyloxime); 2- (o-chlorophenyl) -4,5-diphenylimidazole di Metrics, 2- (o-chlorophenyl) -4,5-bis (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxy) Phenyl) -4,5-diphenyl imidazole 2,4,5-Triarylimidazole dimer such as rudimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer; 9-phenylaclydin, 1,7-bis (9) Acrydin derivatives such as 9'-acrydinyl) heptane; N-phenylglycine, N-phenylglycine derivatives; coumarin compounds; benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylicized benzophenone, 4-Benzoyl-4'-methyldiphenylsulfide, 3,3', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis Examples thereof include benzophenone compounds such as (diethylamino) benzophenone.
The substituents on the aryl groups of the two 2,4,5-triarylimidazoles in the above 2,4,5-triarylimidazole dimer may give the same and symmetric compounds, or differently. Asymmetric compounds may be given. Further, a thioxanthone-based compound and a tertiary amine compound may be combined, such as a combination of diethyl thioxanthone and dimethylaminobenzoic acid. These are used alone or in combination of two or more. Among them, the imidazole dimer has high sensitivity and can be preferably used, and further, the 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer can be usefully used.

The (C) photosensitive resin layer contains (C3a) an ethylene oxide-modified pentaerythritol tetraacrylate (a compound represented by the general formula (i) and having l + m + n + o = 24-48) as the (C3) acrylate monomer. By containing (C3a), the resist piece is dissolved when the resist is peeled off, and the photosensitive resin layer cured during development is less swelled and adheres to the substrate. It is excellent in the above, and the effect that fine lines and dots are stably held in the pattern forming and plating steps can be achieved.

If the value of l + m + n + o in (C3a) is smaller than 24, the undercut (narrowing of the image line width at the bottom of the resist) becomes large, and it is not possible to cope with the miniaturization of the pattern. Further, if the value of l + m + n + o is larger than 48, the (C) photosensitive resin layer swells during development, and it is not possible to cope with the miniaturization of the pattern. Therefore, the value of l + m + n + o in (C3a) is 24 to 48, more preferably 30 to 40.

The (C) photosensitive resin layer may contain "an acrylate monomer other than (C3a)" as the (C3) acrylate monomer. Examples of the "acrylate monomer other than (C3a)" include compounds having one or more acryloyl groups.

Examples of the compound having one acryloyl group include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-hexyl acrylate, and 2-ethylhexyl acrylate. Cyclohexyl acrylate, benzyl acrylate, isomiristyl acrylate, stearyl acrylate, nonylphenoxypolyethylene glycol acrylate (one or more ethoxy groups), 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, glycidyl acrylate, lauryl acrylate, tetrahydrofurfuryl acrylate, 2 -(Dimethylamino) ethyl acrylate, 2- (diethylamino) ethyl acrylate, 2,2,2-trifluoroethyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, glycerin monoacrylate, methoxypolyethylene glycol acrylate (ethoxy) 2 to 30 groups), phenoxypolyethylene glycol acrylate (2 to 30 ethoxy groups), methoxypolypropylene glycol acrylate (2 to 30 propoxy groups), phenoxypolypolyglycol acrylate (2 to 30 propoxy groups), 2-acryloyloxy Examples thereof include ethyl succinate, 2-hydroxy-3-phenoxypropyl acrylate, and ethoxylated o-phenylphenol acrylate. The "ethoxy group" is "-CH ₂ CH ₂ O-". The "propoxy" - a "C _{3 H} 6 _O-", may be linear or may be branched.

Examples of the compound having two acryloyl groups include a compound obtained by reacting a polyhydric alcohol with two acrylic acids. Further, for example, ethylene glycol diacrylate, polyethylene glycol diacrylate (ethoxy group number 2 to 30), propylene glycol diacrylate, polypropylene glycol diacrylate (propoxy group number 2 to 30), polytetramethylene glycol diacrylate, neopentyl glycol. Diacrylate, 3-methyl-1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, 1,10-decanediol diacrylate, 1,9-nonanediol diacrylate, dimethylol tricyclodecane diacrylate , Diacrylate of ethylene oxide adduct of bisphenol A (2 to 30 ethoxy groups), Diacrylate of propylene oxide adduct of bisphenol A (2 to 40 propoxy groups), ethylene oxide of bisphenol A and propylene oxide adduct Diacrylate (sum of ethoxy group and propoxy group 2-40), neopentyl glycol diacrylate hydroxypivalate, 9,9-bis [4- (2-acryloyloxyester) phenyl] fluorene, tricyclodecanedimethanol Diacrylate and the like can be mentioned.

Examples of the compound having three or more acryloyl groups include a compound obtained by reacting a polyhydric alcohol with acrylic acid. Also, for example, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethylene oxide-modified pentaerythritol triacrylate, trimethylolpropane triacrylate. Glysidyl ether triacrylate, ethylene oxide-modified isocyanuric acid triacrylate, ε-caprolactone-modified tris- (2-acryloxyethyl) isocyanurate, glycerin triacrylate, ethylene oxide-modified glycerin triacrylate, ethylene oxide-modified pentaerythritol tetraacrylate (general formula) (I), examples of the compound in which l + m + n + o is less than 24 and more than 48).

The content of (C3a) according to the present invention is preferably 30 to 70% by mass, more preferably 35 to 65% by mass, still more preferably 40 to 60% by mass, based on the total amount of the (C3) acrylate monomer. Is. If the content is less than 30% by mass, the undercut may be large, and if the content is more than 70% by mass, the (C) photosensitive resin layer is likely to swell during development and is fine due to development. Lines and dots may come off.

The (C) photosensitive resin layer according to the present invention may contain (C4) methacrylate monomer. Examples of the methacrylate monomer include compounds in which the acryloyl group of the (C3) acrylate monomer is replaced with a methacryloyl group. In the present invention, the content of the methacrylate monomer is preferably 0 to 5% by mass with respect to the (C3) acrylate monomer. When the content of the (C4) methacrylate monomer is more than 5% by mass, the peeled pieces of the cured (C) photosensitive resin layer may become large and may not be dissolved when the resist is peeled off.

The photosensitive resin layer (C) may contain components other than the above (C1) to (C4), if necessary. Such components include solvents, photopolymerization inhibitors, thermosetting inhibitors, plasticizers, colorants (pigments, dyes, pigments), photocolorants, photodecolorizers, thermosetting inhibitors, fillers, defoamers. Agents, flame retardants, adhesion imparting agents, leveling agents, peeling accelerators, antioxidants, fragrances, thermosetting agents, water repellents, oil repellents, etc., respectively, in the total amount of (C1) to (C4) On the other hand, it can be contained in an amount of about 0.01 to 20% by mass. These can be used individually by 1 type or in combination of 2 or more types.

In the (C) photosensitive resin layer, the content of (C1) is preferably 30 to 75% by mass, preferably 35 to 70% by mass, based on the total amount of (C1), (C2), and (C3). Is more preferable, and 40 to 65% by mass is further preferable. If the content of (C1) is less than 30% by mass, the film property may be deteriorated or the developability may be deteriorated. If the content of (C1) exceeds 75% by mass, the resolution of the resist pattern may decrease.

The content of (C2) is preferably 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, based on the total amount of (C1), (C2) and (C3). .. If the content of (C2) is less than 0.1% by mass, the photopolymerizability may be insufficient. On the other hand, if it exceeds 10% by mass, absorption may increase on the surface of the (C) photosensitive resin layer during exposure, and (C) photocrosslinking inside the photosensitive resin layer may be insufficient.

The content of (C3) is preferably 15 to 60% by mass, more preferably 17 to 55% by mass, and 20 to 50% by mass with respect to the total amount of (C1), (C2) and (C3). It is more preferably mass%. If the content of (C3) is less than 15% by mass, the crosslinkability may be lowered and the photosensitivity may be insufficient. On the other hand, if it exceeds 60% by mass, the adhesiveness of the film surface of the (C) photosensitive resin layer may increase.

In the photosensitive resin layer laminate of the present invention, (A) support, (B) peeling layer, and (C) photosensitive resin layer are laminated in this order, and the photosensitive resin layer is further covered on (C) photosensitive resin layer. The films may be laminated. When the photosensitive resin laminate is rolled, a cover film is formed to prevent blocking. The cover film only needs to be peelable from the uncured or cured (C) photosensitive resin layer, and a resin having high releasability is used. Examples thereof include polyalkylene films such as polyethylene films and polypropylene films; and polyalkylene films coated with a release agent such as silicone.

The thickness of the photosensitive resin layer (C) is preferably 3 to 50 μm, more preferably 7 to 20 μm. (C) If the photosensitive resin layer is too thick, problems such as deterioration of resolution and high cost are likely to occur. On the contrary, if it is too thin, the adhesion, etching resistance, plating resistance and the like may be deteriorated.

Examples of the method of (A) forming the (B) release layer on the support film and (B) providing the (C) photosensitive resin layer on the release layer include a roll coater, a comma coater (registered trademark), and a gravure coater. Examples include coating methods such as air knives, die coaters, and bar coaters.

Next, the resist pattern forming method of the present invention will be described in detail. In the present invention, a resist pattern is formed by a photo method.

The base material according to the present invention is appropriately selected depending on the final product. For example, copper, copper-based alloys (titanium-copper alloys, copper-nickel alloys, etc.); nickel; chromium; iron; tungsten; metal oxide films such as ITO and FTO; iron-based alloys such as stainless steel and 42 alloys; aluminum; amorphous alloys; Etc., a metal base material can be used. Further, a copper-clad laminate, an electroless-plated substrate, an electroplated substrate, a flexible copper-clad laminate, a flexible stainless steel plate, a multi-stage structure substrate, etc., which are used for manufacturing printed wiring boards and the like can be used.

A laminating method is used as a method of attaching the photosensitive resin laminate so that the (C) photosensitive resin layer is in contact with at least one surface of the base material. A general thermal laminator for printed circuit boards, a vacuum laminator, etc. can be used. The nip pressure, transfer speed, and roll temperature differ depending on the base material used, but any condition may be used as long as it can be attached by thermal pressure bonding without bubbles or unevenness.

After the photosensitive resin laminate is attached to the base material, (A) the support film is removed.

Next, the desired pattern is exposed. It is preferable to use ultraviolet rays for exposure. The exposure method is performed by direct laser drawing, close contact exposure via a photomask, projection exposure, or the like. As the light source for exposure, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, a xenon lamp, an LED or the like can be used.

Next, development is carried out. A resist pattern is formed by removing (B) the peeling layer and (C) the unexposed portion of the photosensitive resin layer in the development. An alkaline aqueous solution is usefully used as the developer used for development. Examples of the basic compound used in the developing solution include inorganic basic compounds such as alkali metal silicate, alkali metal hydroxide, alkali metal phosphate, alkali metal carbonate, ammonium phosphate, and ammonium carbonate. Organic basic compounds such as ethanolamine, ethylenediamine, propanediamine, triethylenetetramine, morpholin, tetramethylammonium hydroxide; and the like.

In order to adjust the developability of the non-exposed portion on the (C) photosensitive resin layer, it is necessary to adjust the concentration, temperature, spray pressure, ultrasonic conditions, etc. of the developing solution. The higher the temperature of the developing solution, the faster the developing speed, and a temperature of 40 ° C. or higher is preferable. The concentration of the basic compound in the developing solution is preferably 0.1 to 2% by mass in the case of sodium carbonate. As the device, a dip processing device, a shower spray device, or the like can be used.

In the present invention, the resist pattern after alkaline development may be baked. By the baking treatment, (C) the effect of improving the adhesion between the photosensitive resin layer and the base material, the effect of improving the plating resistance and the etching resistance, and the like can be obtained. The baking temperature is preferably 80 ° C. or higher, and the time is preferably 5 minutes or longer. If the base material is copper or the like and is easily discolored by oxidation or the like, the baking treatment is performed at about 80 ° C. If the base material is stainless steel or the like and is a material that is difficult to oxidize, the baking temperature may be 100 ° C. or higher, or a long-term treatment of 30 minutes or longer may be carried out. Further, before the baking treatment, an active light irradiation treatment such as ultraviolet rays may be carried out for the purpose of preventing the (C) photosensitive resin layer from being deformed by heat.

The base material after the resist pattern has been formed can be plated or etched.

Examples of the plating treatment include copper plating treatment and nickel plating. Specifically, it is preferably used in applications such as an additive method for forming a metal circuit, a semi-additive method, and an additive method for producing a high-definition metal mask. After forming a resist pattern on a substrate by a photo method, the resist pattern This is a method of forming a metal pattern / circuit pattern by plating an exposed base material other than a portion.

For example, when producing a printed wiring board, first, a substrate provided with a thin metal layer on an insulating substrate is prepared as a base material. Next, a resist pattern is formed in a portion where the circuit pattern is not formed. Next, electrolytic plating is performed to form a plated metal layer on the surface of the exposed thin metal layer. Subsequently, the resist pattern is removed by the resist peeling step. After that, a metal pattern / circuit pattern is formed by removing the thin metal layer by (flash) etching.

In the case of an etching process, the base material exposed by the etching solution is dissolved and removed. In the present invention, any etching solution, apparatus, or method may be used as long as the substrate can be dissolved and removed. Examples of the etching solution include alkaline ammonia solution, sulfuric acid-hydrogen peroxide solution, cupric chloride solution, persulfate solution, ferric chloride solution, aqua regia and the like. Further, as the apparatus and method, for example, an apparatus and method such as horizontal spray etching and immersion etching can be used. These details are described in "Print Circuit Technology Handbook" (edited by Japan Print Circuit Industry Association, published in 1987, published by Nikkan Kogyo Shimbun).

After performing the plating treatment or the etching treatment, the resist is peeled off with a peeling liquid. An alkaline aqueous solution is usefully used as the stripping solution. Examples of the basic compound used in the stripping solution include inorganic basic compounds such as alkali metal silicate, alkali metal hydroxide, alkali metal phosphate, alkali metal carbonate, ammonium phosphate, and ammonium carbonate. Organic basic compounds such as ethanolamine, ethylenediamine, propanediamine, triethylenetetramine, morpholin, tetramethylammonium hydroxide; and the like.

In the resist stripping step, it is necessary to adjust the concentration, temperature, spray pressure, ultrasonic conditions, etc. of the stripping solution in order to control the solubility in the cured (C) photosensitive resin layer. The higher the temperature of the stripping liquid, the faster the cured (C) photosensitive resin layer dissolves, and a temperature of 40 ° C. or higher is preferable. The concentration of the basic compound in the stripping solution is preferably a concentration suitable for solubility, and when the basic compound is sodium hydroxide or potassium hydroxide, it is preferably 1 to 4% by mass. As the device, a dip processing device, an ultrasonic device, a shower spray device, or the like can be used.

In the present invention, the (C) photosensitive resin layer that has been cured by pattern exposure and optionally baked is dissolved in the resist stripping liquid when it is removed by the resist stripping liquid in the resist stripping step. .. In the present invention, "dissolution" of the cured (C) photosensitive resin layer means that the (C) photosensitive resin layer is dissolved in the release liquid or the resist stripped piece has a size that cannot be visually confirmed. Refers to the state where is very fine. The state in which the resist stripped pieces are very fine includes a state in which the resist stripped pieces are dispersed at the molecular level, a state in which the resist stripped pieces are dispersed at the molecular aggregate level, a state in which the resist stripped pieces are dispersed as fine particles of 100 μm or less, and the like.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to this example.

Prepare polyvinyl alcohol for the release layers 1 to 5 shown in Table 1, add 95 parts by mass of water to 5 parts by mass, dissolve by stirring with warm water, and dissolve in 5 parts by mass of a polyvinyl alcohol aqueous solution (release layer). Coating liquid) was obtained.

Next, using a wire bar, an aqueous polyvinyl alcohol solution was applied onto a polyethylene terephthalate (PET) film ((A) support film, trade name: Diafoil (registered trademark) T100, 25 μm thickness, manufactured by Mitsubishi Chemical Corporation). It was coated and dried at 90 ° C. for 10 minutes to remove water, and (B) release layers 1 to 5 were provided on a PET film with a thickness of 2 μm. (B) There were no pinholes on the film surfaces of the release layers 1 to 3, and the variation in thickness was within ± 10%, which was a small range, and the release layer was a good (B) release layer. (B) Pinholes were generated on the film surfaces of the release layers 4 and 5 at ^{a ratio of several tens of pieces / m 2} , and the thickness varied widely in the range of 1 to 3 μm.

Next, each component of the (C) photosensitive resin layer of Examples 1 to 3 and Comparative Examples 1 to 5 shown in Table 2 was mixed to obtain a coating liquid for the photosensitive resin layer. The unit of each component compounding amount in Table 2 is a mass part. In Examples 1 to 3 and Comparative Examples 2 to 5, the coating liquid for the photosensitive resin layer was applied onto each of the release layers by using an applicator so as to correspond to the release layers shown in Table 2. Further, in Comparative Example 1, the coating liquid for the photosensitive resin layer was applied onto the PET film using an applicator. It was dried at 80 ° C. for 8 minutes to remove the solvent, and (C) a photosensitive resin layer (dry film thickness: 15 μm) was provided. As described above, the photosensitive resin laminates of Examples 1 to 3 and Comparative Examples 2 to 5, wherein (A) the support film, (B) the release layer, and (C) the photosensitive resin layer are laminated in this order. A photosensitive resin laminate of Comparative Example 1 was produced, in which (B) there was no release layer, and (A) a support film and (C) a photosensitive resin layer were laminated.

In Table 2, each component is as follows.

(C1) Copolymerized resin obtained by copolymerizing methyl methacrylate / n-butyl acrylate / methacrylic acid at a mass ratio of 64/15/21 (mass average molecular weight 40,000).

(C2-1) 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer (C2-2) 4,4'-bis (diethylamino) benzophenone

(C3-1) Ethylene oxide-modified pentaerythritol tetraacrylate (a compound represented by the general formula (i) and having l + m + n + o = 35, (corresponding to C3a)).
(C3-2) Ethylene oxide-modified pentaerythritol tetraacrylate (a compound represented by the general formula (i) and having l + m + n + o = 4)
(C3-3) Polyethylene glycol # 600 diacrylate (repetition number of ethylene oxide is 14)
(C4) Dimethacrylate of ethylene oxide adduct of bisphenol A (repetition number of ethylene oxide is 10 in total)

Surface treatment such as alkaline degreasing and acid treatment is performed on the stainless steel plate (base material) so that the photosensitive resin laminates of Examples 1 to 3 and Comparative Examples 1 to 5 are brought into contact with the (C) photosensitive resin layer. It was pasted on the surface by the laminating method. The PET film was then peeled off and then exposed via a photomask having a line pattern with lines & spaces of 20, 15, 10 μm. Development was carried out with a 1.0 mass% sodium carbonate aqueous solution (developing solution), and (B) the peeling layer and (C) the photosensitive resin layer of the non-exposed portion were removed to form a resist pattern.

In Comparative Example 1, when the PET film was peeled off and then exposed, (B) there was no peeling layer, so that the photomask adhered to (C) the photosensitive resin layer, causing a problem that the photomask was contaminated. Therefore, in Comparative Example 1, the PET film was exposed without being peeled off.

In Examples 1 to 3, all the line patterns having lines & spaces of 20, 15, and 10 μm were formed on stainless steel, and a good resist pattern could be formed.

In Comparative Example 1, since (B) there was no release layer, the film was exposed from above the PET film, but (C) the photosensitive resin layer remained in the space in all the line patterns having lines and spaces of 20, 15, and 10 μm. There was a problem.

In Comparative Examples 2 and 3, only the line pattern having a line & space of 20 μm could be formed due to the influence of (B) large variation in thickness in the peeling layer, but in the line pattern having a line & space of 15 and 10 μm, There was a problem that the (C) photosensitive resin layer remained in the space. Further, the pinhole defect of (B) the release layer was transferred to (C) the photosensitive resin layer, and a good resist pattern could not be obtained.

In Comparative Example 4, only the line pattern having the line & space of 20 μm could be formed, but in the line pattern having the line & space of 15 and 10 μm, the problem that the (C) photosensitive resin layer remained in the space occurred.

In Comparative Example 5, all the line patterns having lines and spaces of 20, 15, and 10 μm were formed on stainless steel, and a good resist pattern could be formed.

Next, by electrolytic plating using a nickel (Ni) sulfamate bath, a plating film was grown on a portion of the stainless steel sheet not covered by the resist pattern to form a Ni metal layer having a thickness of 10 μm.

Next, in Examples 1 to 3 and Comparative Example 5, the resist was peeled off by immersing in a 3 mass% sodium hydroxide aqueous solution (liquid temperature 50 ° C.). In Examples 1 to 3, the resist stripping pieces did not remain in the space, and good resist stripping was possible. Further, in Examples 1 to 3, as a result of immersing in a 3 mass% sodium hydroxide aqueous solution (liquid temperature 50 ° C.) for 3 hours, the peeled pieces could not be visually confirmed. On the other hand, in Comparative Example 5, the resist stripped pieces remained in the space, and good resist stripping could not be performed. In addition, the resist stripped pieces could be visually confirmed, and the resist stripped pieces were not dissolved in the stripping liquid.

INDUSTRIAL APPLICABILITY The present invention can be used when forming a resist pattern during an etching process or a plating process in the manufacture of a printed wiring board, a lead frame, a metal mask, a shadow mask, a semiconductor package, an electrode member, an electromagnetic wave shield, or the like.

(A) Support film (B) Release layer (C) Photosensitive resin layer

Claims (2)

At least (A) a support film, (B) a release layer, and (C) a photosensitive resin layer are laminated in this order, and (B) the release layer has a saponification degree of 86.0 mol% or less and a degree of polymerization of 900. The following polyvinyl alcohol is contained, and the (C) photosensitive resin layer contains (C1) an alkali-soluble resin, (C2) a photopolymerization initiator and (C3) an acrylate monomer, and is used as a (C3) acrylate monomer. (C3a) A photosensitive resin laminate comprising ethylene oxide-modified pentaerythritol tetraacrylate (a compound represented by the general formula (i) and having l + m + n + o = 24-48).

The photosensitive resin laminate according to claim 1 is attached by a laminating method so that the (C) photosensitive resin layer is in contact with at least one surface of the base material, then (A) the support film is removed, and then the support film is removed. A method for forming a resist pattern, which comprises exposing a desired pattern and then developing (C) a photosensitive resin layer at the same time as removing (B) a release layer with a developing solution.

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