KR102660157B1 - Photosensitive element and method of forming a resist pattern - Google Patents

Abstract

To provide a photosensitive element that achieves both improved resolution and prevention of wrinkles during winding, and a method for forming a resist pattern. A photosensitive element having a support film (A), a photosensitive resin composition layer (B), and a protective film (C) in this order, the photosensitive resin composition layer (B) of the support film (A) defined in JIS B0601-2001; Surface roughness Rz _A1 (nm) of the side in contact, surface roughness Rz _A2 (nm) of the opposite side, surface roughness Rz _C1 (nm) of the side in contact with the photosensitive resin composition layer of the protective film (C), opposite side The surface roughness Rz _C2 (nm) of the surface is as follows (1) to (3):
(1) 1 ＜ Rz _A1 ＜ 100
(2) 300 ＜ Rz _C1 ＜ 600
(3) 40 < Rz _C2 /Rz _A2
It is characterized by satisfying.

Description

Photosensitive element and method of forming a resist pattern

The present invention relates to a photosensitive element and a method of forming a resist pattern.

In electronic devices such as PCs and mobile phones, printed wiring boards and the like are used for mounting components or semiconductors. As a resist for manufacturing printed wiring boards, etc., conventionally, a photosensitive element (photosensitive resin laminate) is formed by laminating a photosensitive resin composition layer on a support film, and further laminating a protective film on the photosensitive resin composition layer as needed. , so-called dry film resists are used (for example, see Patent Document 1 and Patent Document 2).

In such photosensitive elements, in order to improve resolution, high-quality films with few internal foreign substances that block exposed light are preferably used as support films.

Japanese Patent Publication No. 2004-191648 Japanese Patent Publication No. 2019-188612

However, since high-quality films have a low surface roughness, when the photosensitive resin composition layer and the protective film are laminated and wound into a roll, the friction force at the interface in contact with the protective film becomes excessively high, causing wrinkles.

The present invention has been proposed in consideration of such conventional circumstances, and its purpose is to provide a photosensitive element and a resist pattern formation method that both improve resolution and prevent wrinkles during winding.

The present inventors have found that the above problem can be solved by the following technical means.

[1] A photosensitive element having a support film (A), a photosensitive resin composition layer (B), and a protective film (C) in this order,

The surface roughness Rz _A1 (nm) of the surface of the support film (A) on the side in contact with the photosensitive resin composition layer (B), the surface roughness Rz _A2 (nm) of the surface on the opposite side, as defined in JIS B0601-2001, The surface roughness Rz _C1 (nm) of the surface of the protective film (C) on the side in contact with the photosensitive resin composition layer (B), and the surface roughness Rz _C2 (nm) of the surface on the opposite side are as follows (1) to (3). ) :

(1) 1 ＜ Rz _A1 ＜100

(2) 300 ＜ Rz _C1 ＜600

(3) 40 < Rz _C2 /Rz _A2

A photosensitive element, characterized in that it satisfies the following.

[2] The photosensitive element according to [1], where 1 < Rz _A2 < 200.

[3] The photosensitive element according to [1] or [2], wherein 1.1 <Rz _A2 /Rz _A1 <7.

[4] The photosensitive element according to any one of [1] to [3], wherein 1.1 <Rz _C2 /Rz _C1 <10.

[5] The photosensitive element according to any one of [1] to [4], wherein 50 < Rz _C2 /Rz _A2 < 100.

[6] The photosensitive element according to any one of [1] to [5], wherein the number of particles with a diameter of 2 μm or more and 5 μm or less contained in the support film (A) is 30 particles/30 mm2 or less.

[7] The photosensitive element according to any one of [1] to [6], wherein the number of particles with a diameter of 2 μm or more and 5 μm or less contained in the support film (A) is 15 particles/30 mm2 or less.

[8] The photosensitive element according to any one of [1] to [7], wherein the number of particles with a diameter of 2 μm or more and 5 μm or less contained in the support film (A) is 10 particles/30 mm2 or less.

[9] The photosensitive element according to any one of [1] to [8], wherein the titanium element content contained in the support film (A) is 1 ppm or more and 20 ppm or less.

[10] The photosensitive element according to any one of [1] to [9], wherein at least one side of the support film (A) is subjected to a smoothing treatment.

[11] The photosensitive element according to any one of [1] to [10], wherein the support film (A) has a thickness of 5 μm or more and 12 μm or less.

[12] The photosensitive element according to any one of [1] to [11], wherein the surface of the protective film (C) is made of polypropylene resin.

[13] A winding body of a photosensitive element formed by winding the photosensitive element according to any one of [1] to [12].

[14] A lamination process of laminating the photosensitive element according to any one of [1] to [12] on a substrate,

An exposure process of exposing the photosensitive resin composition layer of the photosensitive element, and

A method of forming a resist pattern, including a development step of developing and removing an unexposed portion of the photosensitive resin composition layer.

[15] The method of forming a resist pattern according to [14], wherein the exposure step is performed by a projection exposure method.

According to the present invention, it is possible to provide a photosensitive element and a method for forming a resist pattern that both improve resolution and prevent wrinkles during winding.

1 is a cross-sectional view schematically showing an example of the configuration of the photosensitive element of the present invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail.

[Photosensitive element]

1 is a cross-sectional view schematically showing an example of the configuration of the photosensitive element of the present invention.

The photosensitive element of the present invention is a photosensitive element having a support film (A), a photosensitive resin composition layer (B), and a protective film (C) in this order,

Specified in JIS B0601, the surface roughness Rz _A1 (nm) of the side in contact with the photosensitive resin composition layer of the support film (A), the surface roughness Rz _A2 (nm) of the opposite side, and the photosensitive resin of the protective film (C). The surface roughness Rz _C1 (nm) of the surface on the side in contact with the composition layer and the surface roughness Rz _C2 (nm) of the surface on the opposite side are as follows (1) to (3):

(1) 1 ＜ Rz _A1 ＜100

(2) 300 ＜ Rz _C1 ＜600

(3) 40 < Rz _C2 /Rz _A2

It is characterized by satisfying.

In order to improve the resolution of the photosensitive element, it is preferable to use a high-quality film with few internal foreign substances that block the light to be exposed as the support film (A).

A characteristic of a high-quality film is that the surface roughness is low, especially the surface roughness of the side in contact with the photosensitive resin composition layer (B) is low. However, when a photosensitive element roll (dry film roll) is manufactured using these films, the frictional force with the protective film (C) is too high, and wrinkles are generated when the roll is wound. Therefore, in order to prevent wrinkles from occurring during roll winding, the surface roughness of the surface of the protective film (C) on the side in contact with the support film (A) can be increased.

In order to achieve both the above two problems (improvement of resolution and prevention of wrinkles during winding), the surface roughness of the support film (A) is small, and the surface on the side in contact with the photosensitive resin composition layer (B) is smoother. As for the protective film (C), it is important that the surface on the side in contact with the photosensitive resin composition layer (B) is smooth and the other surface is roughened. That is, the present inventors have come to the conclusion that the ideal is a layer structure in which both the support film (A) and the protective film (C) are smooth to some extent and both have a roughened surface.

Therefore, the present inventors have improved resolution by ensuring that the surfaces of the support film (A) and the protective film (C) are smooth to some extent and by forming a difference in the surface roughness of the support film (A) and the protective film (C). A photosensitive element was achieved that achieved both the ability to prevent wrinkles from forming when wound into a roll.

In the present invention, the above-described configuration is defined using equations (1) to (3). By satisfying all of formulas (1) to (3), the photosensitive element of the present invention has good resolution and is preferably prevented from wrinkling when wound into a roll.

In addition, in this specification, surface roughness is the maximum height Rz measured based on the method specified in JIS B0601-2001. In addition, the value of surface roughness can be measured using a typical surface roughness measuring device such as a laser type, stylus type, optical cutting type, or optical interference type.

＜Support Film (A)＞

The support film (A) according to the present embodiment is a layer or film for supporting the photosensitive resin composition layer (B), and is preferably a transparent base film that transmits actinic light.

Examples of transparent base films include films made of synthetic resins such as polyethylene, polypropylene, polycarbonate, and polyethylene terephthalate. Typically, polyethylene terephthalate (PET), which has appropriate flexibility and strength, is preferably used.

Among these, it is preferable to use a high-quality film with few internal foreign substances. Specifically, high-quality films include PET films synthesized using Ti-based catalysts, PET films with a small diameter and low lubricant content, PET films containing lubricants on only one side of the film, thin-film PET films, and smoothing on at least one side. It is more preferable to use a PET film on which at least one side has been subjected to a roughening treatment such as plasma treatment, etc.

Thereby, the light to be exposed can be irradiated to the photosensitive resin composition layer (B) without being blocked by internal foreign substances, and the resolution of the photosensitive element can be improved.

The number of particles with a diameter of 2 μm or more and 5 μm or less contained in the support film (A) as internal foreign matter is preferably 30 particles/30 mm2 or less, more preferably 15 particles/30 mm2 or less, and 10 particles/30. It is more preferable that it is ㎟ or less.

The titanium element (Ti) content contained in the support film (A) is preferably 1 ppm or more and 20 ppm or less, and more preferably 2 ppm or more and 12 ppm or less. If the titanium element content is 20 ppm or less, the number of internal foreign substances originating from titanium element-containing aggregates can be reduced, and a decrease in resolution can be prevented.

The film thickness of the support film (A) is preferably 5 μm or more and 16 μm or less, and more preferably 6 μm or more and 12 μm or less. The thinner the film thickness of the support film, the fewer internal foreign substances, which can prevent a decrease in resolution. However, if the film thickness is less than 5 ㎛, the film thickness in the winding direction due to tension during the coating and winding manufacturing process It may rupture due to stretching deformation or minor scratches, or wrinkles may occur during lamination due to insufficient strength of the film.

It is preferable that smoothing treatment using a calendar device or the like is performed on at least one side of the support film (A). Thereby, the surface roughness of one side of the support film (A), especially the side in contact with the photosensitive resin composition layer (B), can be reduced, and the effect of the present invention can be made more excellent.

The haze of the support film (A) is preferably 0.01% to 1.5% from the viewpoint of improving the parallelism of the light irradiated to the photosensitive resin composition layer (B) and obtaining higher resolution after exposure and development of the photosensitive element. , more preferably 0.01% to 1.2%, and still more preferably 0.01% to 0.95%.

And in the photosensitive element of this embodiment, the support film (A) satisfies the following equation (1) for the surface roughness of both surfaces.

(1) 1 ＜ Rz _A1 ＜100,

Here, Rz _A1 represents the surface roughness (nm) of the surface of the support film (A) on the side in contact with the photosensitive resin composition layer (B), and Rz _A2 represents the surface roughness (nm) of the surface on the opposite side.

Equation (1) stipulates that both support films (A) are smooth, but one side is a roughened surface. As a result, the photosensitive element has excellent resolution.

Rz _A1 and Rz _A2 are not particularly limited as long as they satisfy the above formula (1), but specifically, Rz _A1 is more preferably 10 nm to 70 nm. Rz _A2 can be a small value regardless of the size of Rz _A1 . Specifically, Rz _A2 is preferably 1 nm < Rz _A2 < 200 nm, preferably 40 nm to 100 nm, and more preferably 50 nm to 90 nm. Moreover, Rz _A2 /Rz _A1 is preferably 1.1 < Rz _A2 /Rz _A1 < 7, and more preferably 1.2 to 5.

<Photosensitive resin composition layer (B)>

The photosensitive resin composition layer (B) is laminated on the support film (A). As the photosensitive resin composition layer (B) according to the present embodiment, a known photosensitive resin composition layer may be used. Typically, the photosensitive resin composition layer contains the following components: (i) an alkali-soluble polymer, (ii) an ethylenically unsaturated double bond-containing component (e.g., an ethylenically unsaturated addition polymerizable monomer), and (iii) photopolymerization. It is formed from a photosensitive resin composition containing an initiator.

(i) The alkali-soluble polymer that is the component preferably has a carboxyl group from the viewpoint of alkali solubility. Moreover, from the viewpoint of the strength of the cured film and the coatability of the photosensitive resin composition, it is preferable that the alkali-soluble polymer also has an aromatic group in its side chain.

The acid equivalent of the alkali-soluble polymer is preferably 100 or more from the viewpoint of the development resistance of the photosensitive resin composition layer and the development resistance, resolution, and adhesion of the resist pattern, and from the viewpoint of the developability and peelability of the photosensitive resin composition layer. , it is preferable that it is 600 or less. More preferably, it is 250 to 550, and even more preferably, it is 300 to 500.

The weight average molecular weight of the alkali-soluble polymer is preferably in the range of 5,000 to 500,000, more preferably 10,000 to 200,000, from the viewpoint of maintaining a uniform thickness of the dry film resist and obtaining resistance to the developer. Preferably it is 18,000 to 100,000.

In this specification, the weight average molecular weight refers to the weight average molecular weight measured using a calibration curve of standard polystyrene by gel permeation chromatography (GPC). The dispersion degree of the alkali-soluble polymer is preferably 1.0 to 6.0.

Examples of alkali-soluble polymers include carboxylic acid-containing vinyl copolymers and carboxylic acid-containing cellulose.

The carboxylic acid-containing vinyl copolymer includes at least one first monomer selected from α,β-unsaturated carboxylic acids, alkyl (meth)acrylate, hydroxyalkyl (meth)acrylate, and (meth)acrylamide. and a compound obtained by vinyl copolymerizing at least one second monomer selected from a compound in which hydrogen on the nitrogen is replaced with an alkyl group or an alkoxy group, styrene and styrene derivatives, (meth)acrylonitrile, and glycidyl (meth)acrylate. am.

Examples of the first monomer used in the carboxylic acid-containing vinyl copolymer include acrylic acid, methacrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, and maleic acid half ester. These first monomers may be used individually or in combination of two or more types.

The content ratio of the structural unit of the first monomer in the carboxylic acid-containing vinyl copolymer is 15 mass% or more and 40 mass% or less, preferably 20 mass% or more and 35 mass% or less, based on the mass of the copolymer. am. If the ratio is less than 15% by mass, development with an aqueous alkaline solution becomes difficult. If the ratio exceeds 40% by mass, the first monomer becomes insoluble in the solvent during polymerization, making synthesis of the copolymer difficult.

Specific examples of the second monomer used in the carboxylic acid-containing vinyl copolymer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, cyclohexyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate Rate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, (meth)acrylamide, N-methylol acrylamide, N-butoxymethylacrylamide, styrene, α-methylstyrene, p -Methyl styrene, p-chlorostyrene, (meth)acrylonitrile, glycidyl (meth)acrylate, etc. are mentioned. These second monomers may be used individually, or may be used in combination of two or more types.

The content ratio of the structural unit of the second monomer in the carboxylic acid-containing vinyl copolymer is 60% by mass or more and 85% by mass or less, preferably 65% by mass or more and 80% by mass, based on the mass of the copolymer. It is as follows.

From the viewpoint of introducing an aromatic group into the side chain, the carboxylic acid-containing vinyl copolymer is made to contain a structural unit of styrene or a styrene derivative such as α-methylstyrene, p-methylstyrene, or p-chlorostyrene as a second monomer. It is more preferable. In this case, the content ratio of the structural unit of styrene or styrene derivative in the carboxylic acid-containing vinyl copolymer is preferably 5 mass% or more and 35 mass% or less, more preferably, based on the mass of the copolymer. is 15 mass% or more and 30 mass% or less.

The weight average molecular weight of the carboxylic acid-containing vinyl copolymer is within the range of 10,000 to 200,000, and preferably within the range of 18,000 to 100,000. If this weight average molecular weight is less than 10,000, the strength of the cured film becomes small. When this weight average molecular weight exceeds 200,000, the viscosity of the photosensitive resin composition becomes too high and its coatability deteriorates.

The carboxylic acid-containing vinyl copolymer is made by adding an appropriate amount of a radical polymerization initiator such as benzoyl peroxide or azoisobutyronitrile to a solution of a mixture of various monomers diluted with a solvent such as acetone, methyl ethyl ketone, or isopropanol, and then overheating. It is preferable to synthesize by stirring. In some cases, synthesis is performed by dropping part of the mixture into the reaction solution. After completion of the reaction, a solvent may be further added to adjust the concentration to the desired concentration. As a means of synthesis, in addition to solution polymerization, block polymerization, suspension polymerization, and emulsion polymerization are also used.

Examples of carboxylic acid-containing cellulose include cellulose acetate phthalate, hydroxyethyl/carboxymethyl cellulose, and the like. The content of the alkali-soluble polymer (A) is preferably in the range of 30% by mass to 80% by mass, more preferably 40% by mass to 65% by mass, based on the total mass of the photosensitive resin composition. If this content is less than 30% by mass, the dispersibility in an alkaline developer decreases, and the development time becomes significantly longer. When this content exceeds 80% by mass, photocuring of the photosensitive resin composition layer becomes insufficient and resistance as a resist decreases. Alkali-soluble polymers may be used individually, or may be used in combination of two or more types.

As the ethylenically unsaturated addition polymerizable monomer that is the component (ii), known types of compounds can be used. Examples of the ethylenically unsaturated addition polymerizable monomer include 2-hydroxy-3-phenoxypropyl acrylate, phenoxytetraethylene glycol acrylate, and β-hydroxypropyl-β'-(acryloyloxy). Propyl phthalate, 1,4-tetramethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,4-cyclohexanediol di(meth)acrylate, heptapropylene glycol di(meth)acrylate ) Ethylene in the molecules of acrylate, glycerol (meth)acrylate, 2-di(p-hydroxyphenyl)propanedi(meth)acrylate, glycerol tri(meth)acrylate, and trimethylolpropane tri(meth)acrylate. A compound containing at least one type of oxide chain, propylene oxide chain, or tetramethylene oxide chain; a compound containing at least one type of ethylene oxide chain, propylene oxide chain, or tetramethylene oxide chain among the molecules of dipentaerythritol penta(meth)acrylate A compound containing, in the molecule of dipentaerythritol hexa(meth)acrylate, at least one of an ethylene oxide chain, a propylene oxide chain, and a tetramethylene oxide chain, fr Trimethylolpropane triglycidyl ether tri(meth) Acrylate, Bisphenol A diglycidyl ether di(meth)acrylate, diallyl phthalate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 4-normal octylphenoxypentapropylene glycol acrylate Rate, bis(triethylene glycol methacrylate)nonapropylene glycol, bis(tetraethylene glycol methacrylate)polypropylene glycol, bis(triethylene glycol methacrylate)polypropylene glycol, bis(diethylene glycol acrylate)poly. Ethylene oxide chain in the molecule of propylene glycol, 4-normalnonylphenoxyheptaethylene glycol dipropylene glycol (meth)acrylate, phenoxytetrapropylene glycol tetraethylene glycol (meth)acrylate, and bisphenol A-based (meth)acrylic acid ester monomer. , a compound containing at least one of a propylene oxide chain, and a tetramethylene oxide chain. The ethylenically unsaturated addition polymerizable monomer may be a compound other than the above-mentioned compounds, which may contain at least one of an ethylene oxide chain, a propylene oxide chain, and a tetramethylene oxide chain. It may also contain at least one type of alkylene oxide chain among the methylene oxide chains.

In addition, the ethylenically unsaturated addition polymerizable monomers include polyisocyanate compounds such as hexamethylene diisocyanate and toluylene diisocyanate, 2-hydroxypropyl (meth)acrylate, oligoethylene glycol mono (meth)acrylate, and oligoacrylate. Urethaneized compounds of hydroxyacrylate compounds such as propylene glycol mono(meth)acrylate can also be used. These ethylenically unsaturated addition polymerizable monomers may be used individually, or may be used in combination of two or more types.

The content of the ethylenically unsaturated addition polymerizable monomer is preferably 20% by mass or more and 70% by mass or less, more preferably 30% by mass or more and 60% by mass or less, based on the total mass of the photosensitive resin composition. If this content is less than 20 mass%, curing of the photosensitive resin is not sufficient and the strength as a resist is insufficient. On the other hand, if this content exceeds 70% by mass, when the photosensitive element is stored in a roll, a phenomenon in which the photosensitive resin composition layer or the photosensitive resin composition gradually protrudes from the end face of the roll, that is, edge fusion, is likely to occur.

(iii) The photopolymerization initiator as a component includes, for example, benzyl dimethyl ketal, benzyl diethyl ketal, benzyl dipropyl ketal, benzyl diphenyl ketal, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin. Inphenyl ether, thioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diisopropyl Thioxanthone, 2-fluorothioxanthone, 4-fluorothioxanthone, 2-chlorothioxanthone, 4-chlorothioxanthone, 1-chloro-4-propoxythioxanthone, benzophenone, 4,4 Aromatic ketones such as '-bis(dimethylamino)benzophenone [Michler's ketone], 4,4'-bis(diethylamino)benzophenone, and 2,2-dimethoxy-2-phenylacetophenone; Biimidazole compounds such as 2-(o-chlorophenyl)-4,5-diphenylimidazolyl dimer; Acridines such as 9-phenylacridine; Aromatic initiators such as α,α-dimethoxy-α-morpholino-methylthiophenylacetophenone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; N-arylamino acids such as phenylglycine and N-phenylglycine; Oxime esters such as 1-phenyl-1,2-propanedione-2-o-benzoyloxime and ethyl 2,3-dioxo-3-phenylpropionate-2-(o-benzoylcarbonyl)-oxime; p-dimethylaminobenzoic acid, p-diethylaminobenzoic acid, p-diisopropylaminobenzoic acid, esterification products thereof with alcohol, p-hydroxybenzoic acid ester, etc. Among them, the combination of 2-(o-chlorophenyl)-4,5-diphenylimidazolyl dimer and Michler's ketone or 4,4'-(diethylamino)benzophenone is preferable.

The content of the photopolymerization initiator is preferably 0.01% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 10% by mass or less, based on the total mass of the photosensitive resin composition. If this content is less than 0.01% by mass, sensitivity is not sufficient. When this content exceeds 20% by mass, the ultraviolet absorption rate increases and curing of the bottom portion of the photosensitive resin composition layer becomes insufficient.

In order to improve the thermal stability and/or storage stability of the photosensitive resin composition layer (B) according to the present embodiment, it is preferable to contain a radical polymerization inhibitor in the photosensitive resin composition or the photosensitive resin composition layer. As a radical polymerization inhibitor, for example, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxylbenzoate free radical, 2,2,6,6-tetramethylpiperidine 1 -TEMPO derivatives such as oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, phenothiazine, N,N-diethylhydroxyamine, naphthylamine, N -(1-methylheptyl)-N'-phenyl-p-phenylenediamine, amines such as 4,4'-dicumyl-diphenylamine, catechols such as 4-t-butylpyrocatechol, p-benzo Quinones such as quinone, hydroquinone, 2-hydroxy-1,4-naphthoquinone, t-butylhydroquinone, methylhydroquinone, 2,5-di-tert-butylhydroquinone, di-t-butyl- Quinonemethides such as 7-phenylquinonemethide, cuperone, copper (II) dibutyldithiocarbamate, chelate compounds such as N-nitroso-N-phenylhydroxyamine aluminum, 2-tert-butyl -4,6-dimethylphenol, bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionic acid] [ethylenebis(oxyethylene)], 2,2'-methylenebis[6-( 1-methylcyclohexyl)-p-cresol, 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, octyl-3,5-di-tert-butyl-4- Hydroxy-hydrohexic acid, 2,2-bis[[[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]oxy]methyl]propane-1,3-diol 1, 3-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], p-methoxyphenol, 4,4'-butylidenebis(6-t-butyl- Phenol derivatives such as 3-methylphenol), pyrogallol, cuprous chloride, etc. are included.

In this embodiment, the photosensitive resin composition layer (B) may contain coloring substances such as dye and pigment. Coloring substances include, for example, fuchsin, phthalocyanine green, auramine base, calcoxide green S, para magenta, crystal violet, methyl orange, Nile blue 2B, Victoria blue, malachite green, basic blue 20, diamond green, etc. I can hear it.

In this embodiment, the photosensitive resin composition layer (B) may contain a chromogenic dye that develops color when irradiated with light. As a colorimetric dye, for example, a combination of a leuco dye and a halogen compound is known. Examples of leuco dyes include tris(4-dimethylamino-2-methylphenyl)methane [Leuco Crystal Violet], tris(4-dimethylamino-2-methylphenyl)methane [Leuco Malachite Green], and the like. Halogen compounds include, for example, amyl bromide, isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzal bromide, methylene bromide, tribromomethylphenylsulfone, carbon tetrabromide, and tris (2,3 -Dibromopropyl) phosphate, trichloroacetamide, amyl iodide, isobutyl iodide, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, hexachloroethane, etc. .

In this embodiment, if necessary, additives such as a plasticizer may be contained in the photosensitive resin composition layer (B). Additives include, for example, phthalic acid esters such as diethyl phthalate, o-toluenesulfonate amide, p-toluenesulfonate amide, tributyl citrate, triethyl citrate, triethyl acetylcitrate, tri-n-propyl acetylcitrate, Examples include tri-n-butyl acetyl citrate, polypropylene glycol, polyethylene glycol, polyethylene glycol alkyl ether, and polypropylene glycol alkyl ether.

The thickness of the photosensitive resin composition layer (B) is preferably 3 to 100 μm, and a more preferable upper limit is 50 μm. Resolution improves as the thickness of the photosensitive resin layer approaches 3 μm, and film strength improves as the thickness of the photosensitive resin layer approaches 100 μm, so it can be appropriately selected depending on the application.

＜Protective Film (C)＞

The protective film (C) is laminated on the photosensitive resin composition layer (B) side of the laminated body of the support film (A) and the photosensitive resin composition layer (B), and functions as a cover.

Since the adhesive force between the photosensitive resin composition layer (B) and the protective film (C) is sufficiently smaller than the adhesive force between the photosensitive resin composition layer (B) and the support film (A), the protective film (C) is attached to the photosensitive resin composition layer (B). ) can be easily peeled off. For example, polyethylene film, polypropylene film, stretched polypropylene film, etc. can be preferably used as the protective film (C). It is more preferable that at least the surface of the protective film (C) is made of polypropylene resin.

The film thickness of the protective film (C) is preferably 10 to 100 μm, and more preferably 10 to 50 μm. The protective film (C) includes, for example, EM-501, E-200, E-201F, FG-201, MA-411 manufactured by Oji Ftex Co., Ltd., KW37, 2578, 2548 manufactured by Toray Co., Ltd. 2500, YM17S, GF-18 manufactured by Tamapoli Co., Ltd., GF-818, GF-858, etc.

And in the photosensitive element of this embodiment, the protective film (C) satisfies the following equation (2) with respect to the surface roughness of both surfaces.

(2) 300 ＜ Rz _C1 ＜ 600

Here, Rz _C1 represents the surface roughness (nm) of the surface of the protective film (C) on the side in contact with the photosensitive resin composition layer (B).

Formula (2) specifies that the surface roughness of the protective film (C) on the side in contact with the photosensitive resin composition layer (B) is small. As a result, the photosensitive element has excellent resolution.

Additionally, it is preferable that 1.1 < Rz _C2 /Rz _C1 < 10.

Here, Rz _C2 represents the surface roughness (nm) of the surface of the protective film (C) on the opposite side to the side in contact with the photosensitive resin composition layer (B).

Rz _C1 and Rz _C2 are not particularly limited as long as they satisfy the above formula (2), but specifically, Rz _C1 is preferably 350 nm to 550 nm. Rz _C2 is preferably 400 nm to 5500 nm, and more preferably 450 nm to 4500 nm. Moreover, it is more preferable that Rz _C2 /Rz _C1 is 1.5 to 9.0.

In addition, in the photosensitive element of this embodiment, the support film (A) and the protective film (C) satisfy the following equation (3) for the surface roughness of both surfaces.

(3) 40 < Rz _C2 /Rz _A2

Here, Rz _A2 represents the surface roughness (nm) of the surface of the support film (A) opposite to the side in contact with the photosensitive resin composition layer (B), and Rz _C2 represents the photosensitive resin composition of the protective film (C). It represents the surface roughness (nm) of the surface opposite to the side in contact with the layer (B).

Formula (3) specifies that there is a certain or more difference between the surface roughness of the support film (A) and the surface roughness of the protective film (C) on the side opposite to the side in contact with the photosensitive resin composition layer (B), there is. Thereby, generation of wrinkles when winding the photosensitive element into a roll is preferably prevented.

The upper limit of Rz _C2 /Rz _A2 is preferably less than 100, and more preferably 50 < Rz _C2 /Rz _A2 < 100. Rz _C2 /Rz _A2 is more preferably 40 to 80.

By satisfying all of the above-mentioned formulas (1) to (3), the photosensitive element of the present invention has good resolution and is preferably prevented from forming wrinkles when wound into a roll.

[Photosensitive element roll]

A photosensitive element roll in which the above-described photosensitive element is wound is also an aspect of the present invention.

The photosensitive element is wound on a core in a long state and used in the form of a roll. The winding length is not particularly limited, but is preferably 320 m or less from the viewpoint of roll weight and ease of handling. Since efficiency is high when there are many substrates that can be laminated with one photosensitive element roll, the winding length is preferably 100 m or more from the viewpoint of productivity.

(Windsight)

The core is sometimes also called the core. The shape is not particularly limited, but may be cylindrical or columnar. Since the photosensitive element is used in electronic materials as an etching or plating resist or as a permanent pattern, it is preferable that the photosensitive element has been treated to prevent oscillation, and is preferably made of a plastic resin. It is desirable that the plastic resin material is light, has excellent strength, and does not generate dust. Examples of such plastic resins include polypropylene (PP) resin, acrylonitrile butadiene styrene (ABS) resin, nylon resin, and polyvinyl chloride resin, with ABS resin being preferred. The diameter of the core is not particularly limited, but is preferably 2 to 5 inches, more preferably 3 inches, so that it can be mounted on the device when the photosensitive element roll is mounted on the laminator. The length of the core (when using a cylindrical or cylindrical core, the axial length) may be the same or shorter than the width of the photosensitive element. However, it is preferable that the length of the core is larger than the width of the photosensitive element so that appropriate protrusions can be secured on both sides when the photosensitive element is wound. This is preferable because the ring-shaped sheet is mounted so as to be inserted into this protrusion. Additionally, by fitting a bearing called a core holder to this protrusion, the photosensitive element roll can be stored suspended in the air to prevent it from moving.

The photosensitive element roll may be arranged so that the roll end face protection member contacts the end face of the wound photosensitive element (the width direction end side of the strip-shaped photosensitive element).

In particular, in the photosensitive element roll of this embodiment, since the surface roughness of both surfaces of the support film (A) and the protective film (C) is specified as described above, wrinkles during winding are preferably prevented. Additionally, by maintaining the frictional force between the support film (A) and the protective film (C) in an appropriate range, winding misalignment is less likely to occur when the roll is stored perpendicular to the ground. Additionally, since the roll surface is less likely to be charged due to excessive friction even during use, it becomes easier to prevent the adhesion of dust and dirt.

The method of forming a resist pattern using the photosensitive element or its roll according to this embodiment includes the following steps:

A lamination process of stacking a photosensitive element on a substrate;

An exposure process of exposing the photosensitive resin composition layer of the photosensitive element; and

A development step of developing and removing the unexposed portion of the photosensitive resin composition layer;

are preferably included in this order.

In the lamination process, specifically, after peeling the protective film (C) from the photosensitive element, the photosensitive resin composition layer is heat-pressed on the surface of a support (for example, a substrate) using a laminator, and laminated once or multiple times. Materials of the substrate include, for example, copper, stainless steel (SUS), glass, and indium tin oxide (ITO). The heating temperature during lamination is generally 40°C to 160°C. Heat compression can be performed using a two-stage laminator equipped with two rolls, or by passing the laminate of the substrate and the photosensitive resin composition layer through the rolls repeatedly several times.

In the exposure process, the photosensitive resin composition layer is exposed to active light using an exposure machine. Exposure can be performed after peeling off the support, as desired. When exposing through a photomask, the exposure amount is determined by the light source illuminance and exposure time, and may be measured using the total amount of light. In the exposure process, direct imaging exposure may be performed. In direct imaging exposure, exposure is performed directly on the substrate using a drawing device without using a photo mask. As a light source, a semiconductor laser or an ultra-high pressure mercury lamp with a wavelength of 350 nm to 410 nm is used. When the drawing pattern is controlled by a computer, the exposure amount is determined by the illuminance of the exposure light source and the moving speed of the substrate.

The light irradiation method used in the exposure process is preferably at least one type selected from the projection exposure method, proximity exposure method, contact exposure method, direct imaging exposure method, and electron beam drawing method, and is performed by the projection exposure method. It is more preferable.

In the development process, the unexposed part or exposed part in the photosensitive resin composition layer after exposure is removed with a developing solution using a developing device. After exposure, if there is a support film on the photosensitive resin composition layer, it is removed. Subsequently, the unexposed area or the exposed area is developed and removed using a developer consisting of an aqueous alkaline solution, and a resist image is obtained.

As the alkaline aqueous solution, aqueous solutions such as Na ₂ CO ₃ and K ₂ CO ₃ are preferable. The aqueous alkaline solution is selected according to the characteristics of the photosensitive resin composition layer, but an aqueous Na ₂ CO ₃ solution with a concentration of 0.2% by mass to 2% by mass is generally used. In the alkaline aqueous solution, a surface active agent, an antifoaming agent, a small amount of an organic solvent to promote development, etc. may be mixed. The temperature of the developing solution in the development process is preferably maintained constant within the range of 20°C to 40°C.

Although a resist pattern is obtained through the above-described process, a heating process may be additionally performed at 60°C to 300°C, depending on desired conditions. By performing this heating process, the chemical resistance of the resist pattern can be improved. In the heating process, a heating furnace using hot air, infrared rays, or far infrared rays can be used.

To obtain a conductor pattern, a conductor pattern formation process of etching or plating the substrate on which the resist pattern is formed may be performed after the development process or heating process.

The method of manufacturing a conductor pattern is, for example, performed by using a metal plate or metal-film insulating plate as a substrate, forming a resist pattern by the resist pattern formation method described above, and then passing through a conductor pattern formation process. In the conductor pattern formation process, a conductor pattern is formed on the substrate surface (for example, copper surface) exposed by development using a known etching method or plating method.

In addition, after manufacturing the conductor pattern by the conductor pattern manufacturing method described above, a peeling process is performed to peel the resist pattern from the substrate using an aqueous solution having stronger alkaline properties than the developer, thereby producing a wiring board having a desired wiring pattern ( For example, a printed wiring board) can be obtained.

The alkaline aqueous solution for stripping (hereinafter also referred to as “removing solution”) is not particularly limited, but an aqueous solution of NaOH or KOH with a concentration of 2% to 5% by mass, or an organic amine-based stripping solution is generally used. do. A small amount of water-soluble solvent may be added to the stripping solution. Examples of water-soluble solvents include alcohol and the like. The temperature of the stripping liquid in the peeling process is preferably within the range of 40°C to 70°C.

In this embodiment, the photosensitive element or its roll is used in manufacturing a printed wiring board; Lead frame manufacturing for IC chip mounting; Precision processing of metal foil, such as metal mask manufacturing; Manufacturing of packages such as ball grid array (BGA) and chip size package (CSP); Manufacturing of tape substrates such as chip-on-film (COF) and tape automated bonding (TAB); Manufacturing of semiconductor bumps; And it can be used in the production of partition walls of flat panel displays, such as ITO electrodes, address electrodes, and electromagnetic wave shields.

In addition, unless otherwise specified, the values of each parameter described above are measured according to the measurement method in the Examples described later.

Example

Next, the present embodiment will be described in more detail through examples and comparative examples. However, this embodiment is not limited to the following examples as long as it does not deviate from the gist. The physical properties in the examples were measured by the following method.

[Measurement of surface roughness]

For the support film and protective film, the surface roughness was measured. After dropping a drop of water on a glass plate, each film was affixed with the measurement side facing up and was used as a measurement sample.

Surface roughness was measured based on the method specified in JIS B0601-2001, using a laser microscope, product name “LEXT OLS4100” manufactured by Olympus Co., Ltd., measuring the length at 10 arbitrary points. The average value of Rz measured at 258 μm was taken as the maximum height Rz (nm). In addition, the temperature at the time of measurement was 23 to 25°C.

The surface roughness of the side in contact with the photosensitive resin composition layer of the support film is Rz _A1 , the surface roughness of the opposite side is Rz _A2 , the surface roughness of the side in contact with the photosensitive resin composition layer of the protective film is Rz _C1 , and the surface roughness of the opposite side is Rz C1. The surface roughness of the cotton was set to Rz _C2 .

[Measurement of the number of particles with a diameter of 2 ㎛ or more and 5 ㎛ or less]

A polarizing filter (OLS4000-QWP) was inserted into the upper part of the objective lens of a laser microscope, product name “LEXT OLS4100” manufactured by Olympus Co., Ltd. Next, the support film sample cut to 30 mm x 30 mm was horizontally suction-fixed on the stage of the laser microscope using a porous suction plate "65 F-HG" manufactured by Universal Technology Laboratory Co., Ltd. and a vacuum pump. The suction-fixed support film was observed at a laser light intensity of 60 (laser wavelength: 405 nm) 50 times that of the objective lens. At this time, to prevent halation due to reflected light from the front and back surfaces of the support film, an area centered at 2 μm in the thickness direction of the support film was set as the measurement section. Then, measurements were performed in a measurement area of 260 μm × 260 μm and 49 measurement points. Measurements were repeated 9 times at random different points.

A histogram was created by processing the measured image under the following conditions: binarization = above threshold, threshold 1 = 10%, particle removal = 15, hole filling = 20. By adding up the number of particles with a maximum diameter (μm) of the histogram of 2 to 5, the number of particles with a diameter of 2 to 5 μm was calculated.

[Measurement of titanium element content]

The titanium element content in the support film _was measured using a fluorescence It was conducted under the following conditions: kV, current 95 kA, spectroscopic crystal LiF, detector SC, 2θ = 86.14 deg, and measurement time 40 seconds.

[Method of producing evaluation samples]

The sample for evaluation was produced as follows.

＜Production of photosensitive elements＞

(Examples 1 to 7, Comparative Examples 1 to 8)

The components shown in Table 1 below (however, the number of each component indicates the amount (part by mass) of the solid content) and methyl ethyl ketone weighed to obtain a solid content concentration of 55% are sufficiently stirred and mixed to form a photosensitive resin. A composition solution was obtained. Details of the components shown in Table 1 are shown in Table 2. Next, a photosensitive resin composition layer was formed by applying a solution of the photosensitive resin composition preparation liquid to the surface of a support film with a width of 500 mm and drying it for 1 minute with hot air at 90°C. At that time, the thickness of the photosensitive resin composition layer after heating was set to 5 μm. Additionally, a protective film was bonded onto the surface of the photosensitive resin composition layer on the side where the support film was not laminated to obtain a photosensitive element. Additionally, the photosensitive element is wound around a cylindrical plastic tube with an outer diameter of 3.5 inches, pressure is applied linearly to the plastic tube using a pressure roll arranged in parallel to the width direction of the winding axis, and the photosensitive element is wound for 500 m with a tension of 7 kg. By winding, a roll of the photosensitive element was obtained.

The types and physical properties of the support films used in the examples and comparative examples are shown in Table 3, and the types and properties of the protective films used in each of the examples and comparative examples are shown in Table 4.

＜Front of the board＞

As an evaluation substrate for imageability, a 0.4 mm thick copper clad laminate on which 35 µm rolled copper foil was laminated was immersed in Mech Etch Bond CZ-8101 (manufactured by Mech Co., Ltd.), and roughening was performed until the etching amount reached 1 µm. It was done.

＜Laminate＞

While peeling off the protective film of the photosensitive element, the photosensitive element is laminated on an image evaluation substrate preheated to 50°C using a hot roll laminator (AL-700, manufactured by Asahi Kasei Co., Ltd.) at a roll temperature of 105°C. An element laminate was obtained. The air pressure was set at 0.35 MPa, and the laminate speed was set at 1.5 m/min.

＜Exposure＞

On the surface side of the support film of the photosensitive element laminate 2 hours after lamination, a line with the width of the exposed area and the unexposed area is 1:1 ratio using a split projection exposure device (UX7-Square70, manufactured by Ushio Electric Co., Ltd.). Exposure was performed using an exposure mask with a pattern. Exposure is the exposure of the photosensitive resin composition pattern after development at the point where the exposed part of the exposure mask = unexposed part = 5 ㎛ when exposing and developing a line pattern where the width of the exposed part and the unexposed part is 1: 1 ratio. The exposure amount was used so that the actual width of the exposed portion and the unexposed portion was 5 μm.

＜Phenomena＞

After peeling off the support film of the photosensitive element laminate, using an alkaline developer (Fuji Kiko Co., Ltd., developer for dry film), spray a 1% by mass Na ₂ CO ₃ aqueous solution at 30°C over a predetermined period of time and develop. was carried out. The development spray time was twice the shortest development time, and the water washing spray time after development was twice the shortest development time. At this time, the shortest time required for the photosensitive resin composition layer in the unexposed portion to completely dissolve was set as the shortest development time.

[evaluation]

The obtained photosensitive element was evaluated for wrinkles during winding and resolution as follows.

＜Wrinkles during winding＞

The roll of the obtained photosensitive element was observed with the naked eye and evaluated according to the following criteria.

Excellent: No wrinkles in the roll

Good: There were wrinkles on the roll, but they disappeared after 3 days of storage.

Possible: The roll had creases, but they disappeared after 7 days of storage.

No: The roll has wrinkles and has not disappeared after 7 days of storage.

＜Resolution＞

In the above-described exposure process, exposure was performed using an exposure mask having a line pattern in which the width of the exposed portion and the unexposed portion were 1:1 ratio. Developed according to the development conditions described above, the minimum line width that is normally formed without the cured resist line being covered or collapsed was evaluated using an optical microscope, and evaluation was performed according to the following criteria. If it was more than possible, it was considered passing.

Excellent: 3 ㎛ or less

Good: More than 3 ㎛ but less than 4 ㎛

Available: greater than 4 ㎛ but less than 5 ㎛

Not allowed: exceeding 5 ㎛

The evaluation results for the photosensitive elements of each Example are shown in Table 5, and the evaluation results for the photosensitive elements of each Comparative Example are shown in Table 6.

As is clear from Table 5, in the embodiment that satisfies all of the above-mentioned equations (1) to (3), not only has excellent resolution, but it is also possible to preferably prevent wrinkles from occurring when winding into a roll. I could see that it was there.

In contrast, as shown in Table 6, when equation (1) was not satisfied, that is, when Rz _A1 was greater than 100, the resolution deteriorated.

Additionally, when equation (2) is not satisfied, that is, when Rz _C1 is 300 or less or 600 or more, resolution is not sufficient or wrinkles are observed during winding.

Moreover, when equation (3) is not satisfied, that is, when Rz _C2 /Rz _A2 is 40 or less, resolution is not sufficient and wrinkles are also observed during winding.

Although embodiments of the present invention have been described above, the present invention is not limited thereto and may be appropriately modified without departing from the spirit of the invention.

By using the photosensitive element according to the present invention, both improvement in resolution and prevention of wrinkles during winding are achieved, and it can be widely used as a dry film resist in forming a resist pattern.

Claims (15)

A photosensitive element having a support film (A), a photosensitive resin composition layer (B), and a protective film (C) in this order,
The surface roughness Rz _A1 (nm) of the surface of the support film (A) on the side in contact with the photosensitive resin composition layer (B), the surface roughness Rz _A2 (nm) of the surface on the opposite side, as defined in JIS B0601-2001, The surface roughness Rz _C1 (nm) of the surface of the protective film (C) on the side in contact with the photosensitive resin composition layer (B), and the surface roughness Rz _C2 (nm) of the surface on the opposite side are as follows (1) to (3). ) :
(1) 1 ＜ Rz _A1 ＜100
(2) 300 ＜ Rz _C1 ＜600
(3) 40 < Rz _C2 /Rz _A2
A photosensitive element, characterized in that it satisfies the following. According to claim 1,
1 ＜ Rz _A2 ＜ 200 phosphorus, photosensitive element. According to claim 1,
1.1 ＜ Rz _A2 /Rz _A1 ＜ 7, photosensitive element. According to claim 1,
1.1 ＜ Rz _C2 /Rz _C1 ＜ 10, photosensitive element. According to claim 1,
50 ＜ Rz _C2 /Rz _A2 ＜ 100, photosensitive element. According to claim 1,
A photosensitive element in which the number of particles with a diameter of 2 μm or more and 5 μm or less contained in the support film (A) is 30 particles/30 mm2 or less. According to claim 1,
A photosensitive element in which the number of particles with a diameter of 2 μm or more and 5 μm or less contained in the support film (A) is 15 particles/30 mm2 or less. According to claim 1,
A photosensitive element wherein the number of particles with a diameter of 2 μm or more and 5 μm or less contained in the support film (A) is 10 particles/30 mm2 or less. According to claim 1,
A photosensitive element wherein the titanium element content contained in the support film (A) is 1 ppm or more and 20 ppm or less. According to claim 1,
A photosensitive element in which smoothing treatment is applied to at least one side of the support film (A). According to claim 1,
A photosensitive element wherein the support film (A) has a thickness of 5 μm or more and 12 μm or less. According to claim 1,
A photosensitive element wherein the surface of the protective film (C) is made of polypropylene resin. A winding body of a photosensitive element formed by winding the photosensitive element according to any one of claims 1 to 12. A lamination process of laminating the photosensitive element according to any one of claims 1 to 12 on a substrate,
An exposure process of exposing the photosensitive resin composition layer of the photosensitive element, and
A method of forming a resist pattern, including a development step of developing and removing an unexposed portion of the photosensitive resin composition layer. According to claim 14,
A method of forming a resist pattern, wherein the exposure step is performed by a projection exposure method.

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