Photosensitive element, method for forming resist pattern, and method for manufacturing printed wiring board

Abstract

One embodiment of the present disclosure relates to a photosensitive element comprising a support film containing a lubricant and a photosensitive layer formed on a first surface of the support film. The support film includes a first lubricant layer, a base material layer, and a second lubricant layer, and has the first lubricant layer on the first surface side of the support film and the second lubricant layer on the second surface side of the support film. The second lubricant layer contains an organic lubricant and does not contain an inorganic lubricant. The number of the organic lubricant of 0.8 μm or more in particle diameter included in the second surface is 2 or more per 0.0225 mm2, and the surface roughness Rz of the first surface and the second surface is less than 100 nm.

Description

Photosensitive element, method for forming resist pattern, and method for manufacturing printed wiring board

[0001] The present disclosure relates to a photosensitive element, a method for forming a resist pattern, and a method for producing a printed wiring board.

[0002] In the field of printed wiring board manufacturing, photosensitive elements comprising a layer formed on a support film using a photosensitive resin composition (hereinafter also referred to as a "photosensitive layer") are widely used as resist materials used in etching processes, plating processes, and the like.

[0003] Printed wiring boards are manufactured using a photosensitive element, for example, by the following procedure. That is, first, the photosensitive layer of the photosensitive element is laminated onto a circuit-forming substrate such as a copper-clad laminate. Next, the photosensitive layer is exposed to light through a mask film or the like to form a photocured portion. At this time, the support film is peeled off before or after exposure. Thereafter, areas of the photosensitive layer other than the photocured portion are removed with a developer to form a resist pattern. Next, using the resist pattern as a resist, an etching process or a plating process is performed to form a conductor pattern, and finally, the photocured portion of the photosensitive layer (resist pattern) is peeled off (removed).

[0004] Known support films for use in photosensitive elements include those having a specific haze value and those having a specific lubricant particle size (see, for example, Patent Documents 1 and 2).

[0005] JP 2001-13681 A JP 2014-74764 A

[0006] In recent years, the trend toward higher resolution in circuit formation has led to demands for finer conductor patterns, and therefore for finer resist patterns for forming the conductor patterns. However, the lubricant contained in the support film can scatter light during exposure, which can cause roughness (unevenness) in the contours of the resist pattern.

[0007] An object of the present disclosure is to provide a photosensitive element that is excellent in the ability to form a fine resist pattern, a method for forming a resist pattern using the photosensitive element, and a method for producing a printed wiring board.

[0008] One aspect of the present disclosure relates to the following photosensitive element, method for forming a resist pattern, and method for producing a printed wiring board.

[0009] [1] A photosensitive layer is provided which includes a support film containing a lubricant and a photosensitive layer formed on a first surface of the support film, the support film being composed of a first lubricant layer, a base layer, and a second lubricant layer, the first lubricant layer being on the first surface side, and the second lubricant layer being on the second surface side of the support film, the second lubricant layer containing an organic lubricant and no inorganic lubricant, and the number of organic lubricants having a particle size of 0.8 μm or more contained on the second surface is 0.0225 mm ２ [2] The number of organic lubricants with particle diameters of 0.8 μm or more contained on the second surface is 2 or more per 1000 nm, and the surface roughness Rz of the first surface and the second surface is less than 100 nm. ２ [3] The photosensitive element according to the above [1], wherein the total number of organic lubricants contained in the second surface is 100 or less per 0.0225 mm ２ [4] The photosensitive element according to the above [1] or [2], wherein the number of lubricant particles having a particle size of 0.8 μm or more contained in the first surface is 300 or less per 1000 particles. ２ [5] The photosensitive element according to any one of the above [1] to [3], wherein the total number of lubricants contained in the first surface is 100 or less per 0.0225 mm ２

[0013] The photosensitive element according to any one of [1] to [4] above, wherein the surface roughness is 1,000 or less per unit area. [6] The photosensitive element according to any one of [1] to [5] above, wherein the support film is a biaxially oriented polyester film. [7] A method for forming a resist pattern, comprising: a lamination step of laminating the photosensitive element according to any one of [1] to [6] above on a substrate in the order of a photosensitive layer and a support film; an exposure step of irradiating predetermined portions of the photosensitive layer with actinic rays through the support film to form photocured portions; and a development step of removing regions of the photosensitive layer other than the photocured portions. [8] A method for producing a printed wiring board, comprising a step of etching or plating a substrate having a resist pattern formed by the method for forming a resist pattern according to [7] above, to form a conductor pattern.

[0010] According to the present disclosure, it is possible to provide a photosensitive element that is excellent in the ability to form a fine resist pattern, a method for forming a resist pattern using the photosensitive element, and a method for producing a printed wiring board.

[0011] 1 is a schematic cross-sectional view showing an embodiment of a photosensitive element;FIG. 2 is a schematic cross-sectional view showing an embodiment of a support film;FIG.

[0012] Hereinafter, embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments.

[0013] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. A numerical range "A or greater" means a range exceeding A and A. A numerical range "A or less" means a range exceeding A and A. In the numerical ranges described in stages in this specification, the upper limit or lower limit of a numerical range in a certain stage can be arbitrarily combined with the upper limit or lower limit of a numerical range in another stage. In the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples.

[0014] In this specification, "A or B" means that either A or B is included, or both are included. Unless otherwise specified, the materials exemplified in this specification can be used singly or in combination of two or more. When a composition contains multiple substances corresponding to each component, the content of each component refers to the total amount of the multiple substances present in the composition, unless otherwise specified. The terms "layer" and "film" encompass not only structures that are formed over the entire surface when observed in a plan view, but also structures that are formed on only a portion of the surface. The term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from other processes, as long as the intended effect of the process is achieved.

[0015] In this specification, "(meth)acrylate" means at least one of an acrylate and the corresponding methacrylate. The same applies to other similar expressions such as "(meth)acrylic acid." "EO" refers to ethylene oxide, and an "EO-modified" compound refers to a compound having an oxyethylene group. "PO" refers to propylene oxide, and a "PO-modified" compound refers to a compound having an oxypropylene group. "Solid content" refers to the non-volatile content excluding volatile substances such as water and solvent contained in a photosensitive resin composition, and refers to the components that remain without volatilizing when the resin composition is dried, and also includes liquid, starch syrup-like, and wax-like components at room temperature around 25°C.

[0016] [Photosensitive Element] The photosensitive element according to this embodiment includes a support film containing a lubricant and a photosensitive layer formed on a first surface of the support film, the support film being composed of a first lubricant layer, a base layer, and a second lubricant layer, the first lubricant layer being on the first surface side, and the second lubricant layer being on the second surface side of the support film, the second lubricant layer containing an organic lubricant but not containing an inorganic lubricant, and the number of organic lubricants having a particle size of 0.8 μm or more contained on the second surface is 0.0225 mm ２ The surface roughness Rz of the first surface and the second surface is less than 100 nm.

[0017] Fig. 1 is a schematic cross-sectional view showing one embodiment of a photosensitive element. As shown in Fig. 1, the photosensitive element 1 according to this embodiment includes a support film 10 and a photosensitive layer 20. The photosensitive layer 20 is provided on a first surface 10a of the support film 10. The support film 10 has a second surface 10b opposite to the first surface 10a.

[0018] A lubricant is added to the support film 10 to improve its slipperiness, and the lubricant is contained on both sides of the support film 10. The lubricant is not particularly limited as long as it does not impair the light transmittance of the support film and is a component used in producing polyester films, and may be an inorganic lubricant or an organic lubricant.

[0019] Examples of inorganic lubricants include inorganic particles containing, as an inorganic component, silica, calcium carbonate, alumina (aluminum oxide), aluminum silicate, mica, clay, talc, wollastonite, kaolin, zinc oxide, barium sulfate, calcium phosphate, calcium, magnesium, barium, zinc, manganese, etc. Examples of organic lubricants include organic particles containing, as an organic component, a styrene-based resin, a (meth)acrylate-based resin, an imide-based resin, an olefin-based resin, a modified olefin-based resin, a silicone-based resin, etc.

[0020] The number of lubricants according to this embodiment is 0.0225 mm ２ The average value per unit area (0.150 mm x 0.150 mm) is shown. Note that lubricants with a particle size of 0.8 μm or more also include agglomerates of lubricant with a particle size of less than 0.8 μm.

[0021] 2 is a schematic cross-sectional view showing one embodiment of a support film according to the present disclosure. The support film 10 has a first lubricant layer 12, a base layer 16, and a second lubricant layer 14. The first lubricant layer 12 is located on the first surface 10a of the support film on which the photosensitive layer 20 is provided. The second lubricant layer 14 is located on the second surface 10b of the support film 10, on the side of the base layer 16 opposite the first lubricant layer 12. The support film may be a biaxially oriented polyester film having a three-layer structure.

[0022] The support film can be produced, for example, by forming a first lubricant layer and a second lubricant layer on a base layer using a known method such as roll coating, flow coating, spray coating, curtain flow coating, dip coating, or slit die coating.

[0023] The substrate layer 16 is a layer that does not contain a lubricant. The substrate layer may be made of a polyester film including polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene-2,6-naphthalate (PEN). The thickness of the substrate layer 16 may be 5 to 40 μm, 8 to 30 μm, or 10 to 25 μm.

[0024] The first and second lubricant layers may be formed by kneading a lubricant into polyester such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polyethylene-2,6-naphthalate (PEN).

[0025] The second lubricant layer 14, which is on the second surface 10b side of the support film that does not come into contact with the photosensitive layer, contains an organic lubricant as the lubricant but does not contain an inorganic lubricant, thereby reducing the roughness of the resist pattern contour.

[0026] The number of organic lubricants having a particle size of 0.8 μm or more contained in the second surface 10b is set to 0.0225 mm from the viewpoint of further reducing the roughness of the contour of the resist pattern. ２ The number of particles per unit area may be 100 or less, 80 or less, 60 or less, 40 or less, 20 or less, or 10 or less.

[0027] The second lubricant layer 14 may contain an organic lubricant having a particle size of less than 0.8 μm. The total number of lubricants contained on the second surface 10b (the number of organic lubricants having a particle size of 0.8 μm or more and the number of organic lubricants having a particle size of less than 0.8 μm) is set to 0.0225 mm from the viewpoint of further enhancing the slipperiness of the support film. ２ From the viewpoint of further reducing the roughness of the contour of the resist pattern, the average particle size may be 10 or more, 50 or more, 60 or more, 70 or more, or 80 or more per 1000 mm. ２ It may be 300 or less, 250 or less, 200 or less, 180 or less, or 150 or less per unit area.

[0028] The first lubricant layer 12 may contain an inorganic lubricant as a lubricant, or may contain both an inorganic lubricant and an organic lubricant. The number of lubricant particles having a particle size of 0.8 μm or more contained on the first surface 10 a is set to 0.0225 mm ２ It may be 100 or less, 80 or less, 60 or less, 40 or less, or 20 or less per unit area, or may be 1 to 100, 2 to 80, 4 to 60, 6 to 40, or 8 to 20.

[0029] The total number of lubricants contained in the first surface 10a is 0.0225 mm ２ It may be 1000 or less, 800 or less, 600 or less, or 500 or less per unit area, or may be 100 to 1000, 200 to 800, 300 to 600, or 400 to 500.

[0030] From the viewpoint of suppressing resist defects, the support film according to this embodiment preferably does not contain a lubricant having a particle size exceeding 3.0 μm. The upper limit of the size of the lubricant (organic lubricant and inorganic lubricant) having a particle size of 0.8 μm or more contained on the first surface 10 a and the second surface 10 b may be 3.0 μm or less, 2.5 μm or less, 2.0 μm or less, or 1.5 μm or less. From the viewpoint of improving handleability, the lower limit of the size of the lubricant having a particle size of 0.8 μm or more contained on the first surface 10 a and the second surface 10 b may be 0.8 μm or more, 0.9 μm or more, 1.0 μm or more, or 1.1 μm or more.

[0031] The average particle size of the lubricant contained on the first surface 10a and the second surface 10b may be 0.2 μm or more, 0.3 μm or more, or 0.4 μm or more from the viewpoint of improving handleability, and may be 1.0 μm or less, 0.8 μm or less, 0.6 μm or less, or 0.5 μm or less from the viewpoint of suppressing resist defects.

[0032] The size and number of lubricants contained in the support film can be measured using a confocal microscope. Examples of confocal microscopes that can be used include the hybrid laser microscope OPTELICS HYBRID (Lasertec Corporation, product name). Observation with a confocal microscope is a measurement technique in which reflected light from an object to be observed is detected by a light-receiving unit. When the object to be observed is in focus (in focus), strong reflected light is obtained, and the light intensity is observed as being strong (often observed as being white). When the object to be observed is out of focus (out of focus), the light intensity is observed as being weak (often observed as being black).

[0033] The numerical aperture (Na) of the objective lens used for observation may be 0.8 from the viewpoint of facilitating accurate and efficient observation. A numerical aperture of 0.8 is more likely to prevent contact between the lens and the object being observed, which would otherwise cause soiling of the microscope, and to prevent excessively high magnification, which would more likely prevent a decrease in the amount of light in the field of view and a decrease in the detection level. Furthermore, a numerical aperture (Na) of 0.8 is more likely to prevent a decrease in resolution, which would reduce errors in detecting the size of the object being observed, compared to a numerical aperture of less than 0.8, making it easier to perform accurate measurements.

[0034] In observation using a confocal microscope, the measurement magnification may be 50x, and the digital zoom in the software may be 2x. When the measurement magnification is 50x, a decrease in the amount of light in the field of view is more likely to be suppressed and a decrease in the detection level is more likely to be suppressed than when the measurement magnification is greater than 50x, and the size of the defect is more likely to be measured accurately than when the measurement magnification is less than 50x. When the digital zoom is 2x, a decrease in the amount of light in the field of view is more likely to be suppressed and a decrease in the detection level is more likely to be suppressed than when the digital zoom is 1x (not set).

[0035] The surface roughness Rz of the first surface 10a is less than 100 nm, and may be 5 to 90 nm, 10 to 80 nm, 15 to 60 nm, 15 to 50 nm, or 20 to 45 nm, from the viewpoint of the resist shape. The surface roughness Rz of the second surface 10b is less than 100 nm, and may be 5 to 90 nm, 10 to 80 nm, 15 to 60 nm, 20 to 45 nm, or 20 to 40 nm, from the viewpoint of the resist shape. Rz is the ten-point average roughness measured in accordance with JIS B 0601:2013.

[0036] The haze value of the support film may be 0.01% or more, 0.05% or more, 0.1% or more, 0.3% or more, 0.5% or more, or 0.7% or more, from the viewpoint of easily improving operability when laminating the photosensitive element to a substrate and operability when forming a photosensitive layer on the support film. The haze value of the support film may be 3.0% or less, 1.5% or less, 0.8% or less, or 0.7% or less, from the viewpoint of easily obtaining good sensitivity and resolution. From these viewpoints, the haze value of the support film may be 0.01 to 3.0%, 0.01 to 1.5%, 0.01 to 0.8%, or 0.01 to 0.7%. "Haze value" means cloudiness. The haze value of the support film can be measured using a commercially available haze meter (turbidity meter, for example, the product name "NDH-5000" manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with the method specified in JIS K 7105.

[0037] The light transmittance of the support film (for example, the light transmittance over the entire wavelength range of 380 to 780 nm) may be in the following ranges. The light transmittance of the support film may be 80% or more, 85% or more, 87% or more, 88% or more, or 89% or more. The light transmittance of the support film may be 95% or less, 93% or less, 90% or less, or 89% or less. From these perspectives, the light transmittance of the support film may be 80 to 95%. The light transmittance of the support film can be measured using a commercially available haze meter (for example, the trade name "NDH-5000" manufactured by Nippon Denshoku Industries Co., Ltd.).

[0038] The thickness of the support film may be 5 μm or more, 10 μm or more, 11 μm or more, 12 μm or more, 15 μm or more, or 16 μm or more, from the viewpoint of preventing the support film from tearing when peeled from the photosensitive element. The thickness of the support film may be 200 μm or less, 100 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, or 18 μm or less, from the viewpoint of easily ensuring focus latitude during exposure. From these viewpoints, the thickness may be 5 to 200 μm, 11 to 100 μm, 12 to 50 μm, or 15 to 40 μm.

[0039] The photosensitive layer 20 is a layer formed from a photosensitive resin composition. The photosensitive resin composition used to form the photosensitive layer 20 may contain (A) a binder polymer (component (A)), (B) a photopolymerizable compound (component (B)), and (C) a photopolymerization initiator (component (C)). The solid content of each component in the photosensitive layer 20 other than the volatile substance may be within the numerical range of the solid content of each component in the photosensitive resin composition.

[0040] Examples of materials constituting the binder polymer (A) include acrylic resins, styrene resins, epoxy resins, amide resins, amide-epoxy resins, alkyd resins, and phenolic resins. The component (A) may contain an acrylic resin, which facilitates obtaining good alkaline developability. The binder polymer used in conventional photosensitive resin compositions can be used as the component (A).

[0041] Component (A) can be produced, for example, by radical polymerization of a polymerizable monomer. Examples of the polymerizable monomer include styrene or a styrene derivative, acrylamide such as diacetone acrylamide, acrylonitrile, vinyl alcohol ethers such as vinyl-n-butyl ether, (meth)acrylic acid alkyl esters, (meth)acrylic acid benzyl esters, hydroxyalkyl (meth)acrylates, (meth)acrylic acid tetrahydrofurfuryl esters, (meth)acrylic acid dimethylaminoethyl esters, (meth)acrylic acid diethylaminoethyl esters, and (meth)acrylic acid glycidyl esters. Examples of the polymerizable monomer include 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, (meth)acrylic acid, α-bromoacrylic acid, α-chloroacrylic acid, β-furyl (meth)acrylic acid, β-styryl (meth)acrylic acid, maleic acid, maleic anhydride, maleic acid monoesters such as monomethyl maleate, monoethyl maleate, and monoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. One polymerizable monomer can be used alone, or two or more can be used in combination.

[0042] From the viewpoint of alkaline developability, the component (A) may have a carboxy group. The component (A) having a carboxy group can be produced, for example, by radical polymerization of a polymerizable monomer having a carboxy group with another polymerizable monomer. The polymerizable monomer having a carboxy group may be (meth)acrylic acid or methacrylic acid.

[0043] From the standpoint of improving alkali developability and alkali resistance in a well-balanced manner, the content of structural units based on polymerizable monomers having a carboxy group may be 10 to 50% by mass, 15 to 40% by mass, or 20 to 35% by mass, based on the total amount of component (A). When the carboxy group content is 10% by mass or more, alkali developability tends to be improved, and when it is 50% by mass or less, alkali resistance tends to be excellent.

[0044] From the viewpoint of adhesion and release properties, component (A) may have a structural unit based on styrene or a styrene derivative. Styrene derivatives are polymerizable compounds in which a hydrogen atom at the α-position or on an aromatic ring of styrene, such as vinyltoluene or α-methylstyrene, is substituted. The content of structural units based on styrene or a styrene derivative in component (A) may be 10 to 60% by mass, 15 to 50% by mass, 35 to 50% by mass, or 40 to 50% by mass. When the content of structural units based on styrene or a styrene derivative is 10% by mass or more, adhesion tends to be improved, while when it is 60% by mass or less, it is possible to prevent peeled pieces from becoming large during development, and the time required for peeling tends to be kept from increasing.

[0045] From the standpoint of improving resolution, component (A) may have structural units based on a benzyl (meth)acrylate ester. The content of structural units derived from a benzyl (meth)acrylate ester in component (A) may be 10 to 40 mass%, 15 to 35 mass%, or 20 to 30 mass%.

[0046] From the standpoint of improving plasticity, component (A) may have a structural unit based on a (meth)acrylic acid alkyl ester. Examples of the (meth)acrylic acid alkyl ester include (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid propyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid pentyl ester, (meth)acrylic acid hexyl ester, (meth)acrylic acid heptyl ester, (meth)acrylic acid octyl ester, (meth)acrylic acid 2-ethylhexyl ester, (meth)acrylic acid nonyl ester, (meth)acrylic acid decyl ester, (meth)acrylic acid undecyl ester, and (meth)acrylic acid dodecyl ester.

[0047] From the viewpoint of further improving resolution and adhesion, component (A) may have a structural unit based on a hydroxyalkyl (meth)acrylate. The hydroxyalkyl (meth)acrylate may be, for example, hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxypentyl (meth)acrylate, hydroxyhexyl (meth)acrylate, etc. Furthermore, when the number of carbon atoms in the alkyl portion of the hydroxyalkyl (meth)acrylate unit is 3 or more, the hydroxyalkyl (meth)acrylate unit may have a branched structure.

[0048] From the viewpoint of excellent adhesion of the resist pattern, the weight average molecular weight (Mw) of the component (A) may be 10,000 or more, 15,000 or more, 20,000 or more, or 25,000 or more, and from the viewpoint of suitable development, it may be 100,000 or less, 80,000 or less, 70,000 or less, or 60,000 or less. The dispersity (Mw / Mn) of the component (A) may be, for example, 1.0 or more, 1.5 or more, or 1.8 or more, and from the viewpoint of further improving adhesion and resolution, it may be 3.0 or less, 2.5 or less, or 2.0 or less.

[0049] The weight average molecular weight (Mw) and dispersity (Mw / Mn) herein can be obtained by measuring by gel permeation chromatography (GPC) and converting using a calibration curve of standard polystyrene.

[0050] From the viewpoint of enabling suitable development, the acid value of the component (A) may be 60 mgKOH / g or more, 80 mgKOH / g or more, 90 mgKOH / g or more, or 100 mgKOH / g or more, and from the viewpoint of improving the adhesion of the resist pattern (developer resistance), the acid value of the component (A) may be 250 mgKOH / g or less, 230 mgKOH / g or less, 210 mgKOH / g or less, or 200 mgKOH / g or less. The acid value of the component (A) can be adjusted by the content of structural units constituting the component (A) (for example, structural units derived from (meth)acrylic acid).

[0051] The component (A) can be used alone or in combination of two or more. When two or more types of the component (A) are used in combination, examples of the component (A) include two or more binder polymers made of different polymerizable monomers, two or more binder polymers having different Mw, and two or more binder polymers having different dispersities.

[0052] The content of component (A) may be 30 to 80 parts by mass, 40 to 75 parts by mass, 50 to 70 parts by mass, or 50 to 60 parts by mass, relative to 100 parts by mass of the total amount of component (A) and component (B), which will be described later. When the content of component (A) is within this range, the strength of the photocured portion of the photosensitive layer is improved.

[0053] The photopolymerizable compound (B) can be a compound having at least one ethylenically unsaturated bond in the molecule. The component (B) can be used alone or in combination of two or more.

[0054] The ethylenically unsaturated bond contained in component (B) is not particularly limited as long as it is photopolymerizable. Examples of the ethylenically unsaturated bond include α,β-unsaturated carbonyl groups such as a (meth)acryloyl group. Examples of photopolymerizable compounds having an α,β-unsaturated carbonyl group include α,β-unsaturated carboxylic acid esters of polyhydric alcohols, bisphenol-type (meth)acrylates, α,β-unsaturated carboxylic acid adducts of glycidyl group-containing compounds, (meth)acrylates having a urethane bond, nonylphenoxy polyethyleneoxy acrylate, (meth)acrylates having a phthalic acid skeleton, and (meth)acrylic acid alkyl esters.

[0055] Examples of α,β-unsaturated carboxylic acid esters of polyhydric alcohols include polyethylene glycol di(meth)acrylate having 2 to 14 ethylene groups, polypropylene glycol di(meth)acrylate having 2 to 14 propylene groups, polyethylene-polypropylene glycol di(meth)acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, EO,PO-modified trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, and (meth)acrylate compounds having a skeleton derived from dipentaerythritol or pentaerythritol. "EO-modified" means that it has a block structure of ethylene oxide (EO) groups, and "PO-modified" means that it has a block structure of propylene oxide (PO) groups.

[0056] From the viewpoint of improving the flexibility of the resist pattern, the component (B) may contain a polyalkylene glycol di(meth)acrylate. The polyalkylene glycol di(meth)acrylate may have at least one of an EO group and a PO group, or may have both an EO group and a PO group. In a polyalkylene glycol di(meth)acrylate having both an EO group and a PO group, the EO groups and the PO groups may each be present in succession in a block form, or may be present randomly. The PO group may be either an oxy-n-propylene group or an oxyisopropylene group. In the (poly)oxyisopropylene group, the secondary carbon of the propylene group may be bonded to an oxygen atom, or the primary carbon may be bonded to an oxygen atom.

[0057] Commercially available polyalkylene glycol di(meth)acrylates include, for example, FA-023M (manufactured by Resonac Corporation), FA-024M (manufactured by Resonac Corporation), and NK Ester HEMA-9P (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0058] From the viewpoint of improving the flexibility of the resist pattern, component (B) may contain a (meth)acrylate having a urethane bond. Examples of (meth)acrylates having a urethane bond include an addition reaction product of a (meth)acrylic monomer having an OH group at the β-position with a diisocyanate (such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, or 1,6-hexamethylene diisocyanate), tris((meth)acryloxytetraethylene glycol isocyanate)hexamethylene isocyanurate, EO-modified urethane di(meth)acrylate, and EO,PO-modified urethane di(meth)acrylate.

[0059] Commercially available EO-modified urethane di(meth)acrylates include, for example, "UA-11" and "UA-21EB" (manufactured by Shin-Nakamura Chemical Co., Ltd.). Commercially available EO, PO-modified urethane di(meth)acrylates include, for example, "UA-13" (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0060] From the viewpoints of facilitating the formation of a thick resist pattern and improving resolution and adhesion in a balanced manner, the component (B) may contain a (meth)acrylate compound having a skeleton derived from dipentaerythritol or pentaerythritol. The (meth)acrylate compound having a skeleton derived from dipentaerythritol preferably has four or more (meth)acryloyl groups, and may be dipentaerythritol penta(meth)acrylate or dipentaerythritol hexa(meth)acrylate.

[0061] The component (B) may contain a polyfunctional (meth)acrylate compound obtained by reacting a polyhydric alcohol with an α,β-unsaturated carboxylic acid. The polyfunctional (meth)acrylate compound may have at least one of an EO group and a PO group, or may have both an EO group and a PO group. Examples of such compounds include dipentaerythritol (meth)acrylate having an EO group. Commercially available dipentaerythritol (meth)acrylate having an EO group include DPEA-12 (manufactured by Nippon Kayaku Co., Ltd.).

[0062] From the viewpoint of improving resolution and release properties after curing, component (B) may contain a bisphenol-type (meth)acrylate, and among bisphenol-type (meth)acrylates, it may contain bisphenol A-type (meth)acrylate. Examples of bisphenol A-type (meth)acrylates include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane.

[0063] Examples of commercially available 2,2-bis(4-((meth)acryloxydiethoxy)phenyl)propane include BPE-200 (manufactured by Shin-Nakamura Chemical Co., Ltd.), and 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane includes BPE-500 (manufactured by Shin-Nakamura Chemical Co., Ltd.) and FA-321M (manufactured by Resonac Corporation).

[0064] Examples of nonylphenoxy polyethyleneoxyacrylates include nonylphenoxytetraethyleneoxyacrylate, nonylphenoxypentaethyleneoxyacrylate, nonylphenoxyhexaethyleneoxyacrylate, nonylphenoxyheptaethyleneoxyacrylate, nonylphenoxyoctaethyleneoxyacrylate, nonylphenoxynonaethyleneoxyacrylate, nonylphenoxydecaethyleneoxyacrylate, and nonylphenoxyundecaethyleneoxyacrylate.

[0065] Examples of (meth)acrylates having a phthalic acid skeleton include γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate, β-hydroxyethyl-β'-(meth)acryloyloxyethyl-o-phthalate, and β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate. γ-Chloro-β-hydroxypropyl-β'-methacryloyloxyethyl-o-phthalate is commercially available as FA-MECH (manufactured by Resonac Corporation).

[0066] The photopolymerization initiator (C) is not particularly limited as long as it can polymerize the component (B), and can be appropriately selected from commonly used photopolymerization initiators. The component (C) can be used alone or in combination of two or more.

[0067] Examples of the component (C) include imidazole compounds, aromatic ketones (excluding compounds corresponding to benzophenone compounds), quinone compounds, benzoin compounds, acridine compounds, N-phenylglycine compounds, and benzyl derivatives.

[0068] Examples of the imidazole compound include 2-(o-chlorophenyl)-4,5-diphenylbiimidazole, 2,2',5-tris-(o-chlorophenyl)-4-(3,4-dimethoxyphenyl)-4',5'-diphenylbiimidazole, 2,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenylbiimidazole, 2,4,5-tris-(o-chlorophenyl)-diphenylbiimidazole, 2-(o-chlorophenyl)-bis-4,5-(3,4-dimethoxyphenyl)-biimidazole, 2,2'-bi bis-(2-fluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3-difluoromethylphenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,4-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, and 2,2'-bis-(2,5-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole.

[0069] Examples of the acridine compound include 9-phenylacridine, 9-(p-methylphenyl)acridine, 9-(m-methylphenyl)acridine, 9-(p-chlorophenyl)acridine, 9-(m-chlorophenyl)acridine, 9-aminoacridine, 9-dimethylaminoacridine, 9-diethylaminoacridine, 9-pentylaminoacridine, 1,2-bis(9-acridinyl)ethane, 1,4-bis(9-acridinyl)butane, 1,6-bis(9-acridinyl)hexane, 1,8-bis(9-acridinyl)octane, Examples of such bis(9-acridinyl)alkanes include 1,10-bis(9-acridinyl)decane, 1,12-bis(9-acridinyl)dodecane, 1,14-bis(9-acridinyl)tetradecane, 1,16-bis(9-acridinyl)hexadecane, 1,18-bis(9-acridinyl)octadecane, and 1,20-bis(9-acridinyl)eicosane; 1,3-bis(9-acridinyl)-2-oxapropane, 1,3-bis(9-acridinyl)-2-thiapropane, and 1,5-bis(9-acridinyl)-3-thiapentane.

[0070] Examples of N-phenylglycine compounds include N-phenylglycine, N-methyl-N-phenylglycine, and N-ethyl-N-phenylglycine. Examples of aromatic ketones include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propanone-1. Examples of quinone compounds include alkylanthraquinones. Examples of benzoin compounds include benzoin, alkylbenzoin, and benzoin ether compounds (such as benzoin alkyl ethers). Examples of benzyl derivatives include benzyl dimethyl ketal.

[0071] The amount of component (C) may be 0.1 to 10 parts by mass, 1 to 5 parts by mass, or 2 to 4.5 parts by mass, relative to 100 parts by mass of the total amount of component (A) and component (B). When the amount of component (C) is 0.1 part by mass or more, photosensitivity, resolution, and adhesion tend to be improved, while when it is 10 parts by mass or less, resist pattern formability tends to be better.

[0072] The photosensitive resin composition according to this embodiment may further contain a photosensitizer as component (D). By containing component (D), it is possible to effectively utilize the absorption wavelength of the actinic ray used for exposure. The component (D) may be used alone or in combination of two or more.

[0073] Examples of component (D) include pyrazoline compounds, benzophenone compounds, anthracene compounds, coumarin compounds, xanthone compounds, thioxanthone compounds, oxazole compounds, benzoxazole compounds, thiazole compounds, benzothiazole compounds, triazole compounds, stilbene compounds, triazine compounds, thiophene compounds, naphthalimide compounds, triarylamine compounds, and aminoacridine compounds. From the viewpoints of easily suppressing the occurrence of defects in the resist, easily shortening the minimum development time, and easily obtaining good sensitivity, resolution, and adhesion, the sensitizer may contain at least one selected from the group consisting of pyrazoline compounds, benzophenone compounds, anthracene compounds, and coumarin compounds.

[0074] Examples of the pyrazoline compound include 1-(4-methoxyphenyl)-3-styryl-5-phenyl-pyrazoline, 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1,5-bis-(4-methoxyphenyl)-3-(4-methoxystyryl)-pyrazoline, 1-(4-isopropylphenyl)-3-styryl-5-phenyl-pyrazoline, 1-phenyl-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, 1,5-bis-(4-isopropylphenyl)-3-(4- isopropylstyryl)-pyrazoline, 1-(4-methoxyphenyl)-3-(4-tert-butyl-styryl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(4-tert-butyl-styryl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(4-isopropyl-styryl)-5-(4-isopropyl 1-(4-methoxyphenyl)-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, 1-phenyl-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,6-dimethoxystyryl)-5 -(2,6-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-(4-methoxyphenyl)-3-(2,4-dimethoxystyryl)-5-(2 ,4-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,5-dimethoxystyryl)-5 -(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butyl-phenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(3,4-dimethoxystyryl)-5- (3,4-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropyl-phenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, and 1-(4-isopropyl-phenyl)-3-(2,4-dimethoxystyryl)-5-(2,The sensitizer may include 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, from the viewpoint of easily obtaining good resolution and adhesion.

[0075] Examples of the benzophenone compound include benzophenone; N,N,N',N'-tetraalkyl-4,4'-diaminobenzophenones such as N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone (also known as Michler's ketone) and N,N,N',N'-tetraethyl-4,4'-diaminobenzophenone; and dialkylaminobenzophenones such as 4-methoxy-4'-dimethylaminobenzophenone. From the viewpoint of easily obtaining good resolution and adhesion, the sensitizer may contain N,N,N',N'-tetraalkyl-4,4'-diaminobenzophenone.

[0076] Examples of the anthracene compound include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene, and 9,10-dipentoxyanthracene. The sensitizer may contain 9,10-dialkoxyanthracene, from the viewpoint of easily obtaining good sensitivity.

[0077] Examples of the coumarin compounds include 7-amino-4-methylcoumarin, 7-dimethylamino-4-methylcoumarin, 7-diethylamino-4-methylcoumarin, 7-methylamino-4-methylcoumarin, 7-ethylamino-4-methylcoumarin, 7-aminocyclopenta[c]coumarin, 7-dimethylaminocyclopenta[c]coumarin, 7-diethylaminocyclopenta[c]coumarin, 4,6-dimethyl-7-dimethylaminocoumarin, and 4,6-dimethyl-7-ethylamino Examples of suitable sensitizers include coumarin, 4,6-dimethyl-7-diethylaminocoumarin, 4,6-diethyl-7-dimethylaminocoumarin, 4,6-diethyl-7-ethylaminocoumarin, 4,6-diethyl-7-dimethylaminocoumarin, 3-benzoyl-7-diethylaminocoumarin, 3,3'-carbonylbis(7-diethylaminocoumarin), and 2,3,6,7-tetrahydro-9-methyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one. From the viewpoint of easily obtaining good sensitivity, the sensitizer may include 2,3,6,7-tetrahydro-9-methyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one.

[0078] From the viewpoint of improving photosensitivity and resolution, the content of the component (D) may be 0.01 to 5 parts by mass, 0.01 to 1 part by mass, or 0.01 to 0.2 parts by mass, relative to 100 parts by mass of the total amount of the component (A) and the component (B).

[0079] The photosensitive resin composition according to this embodiment may further contain, as necessary, additives such as dyes, photocoloring agents, thermal color-developing inhibitors, plasticizers, pigments, fillers, antifoaming agents, flame retardants, adhesion promoters, leveling agents, release promoters, antioxidants, fragrances, imaging agents, thermal crosslinking agents, polymerization inhibitors, etc. These additives may be used alone or in combination of two or more.

[0080] Examples of dyes include malachite green, Victoria Pure Blue, brilliant green, and methyl violet. Examples of photochromic agents include tribromophenyl sulfone, leuco crystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline. Examples of plasticizers include p-toluenesulfonamide.

[0081] The photosensitive resin composition can be dissolved, as necessary, in a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, or propylene glycol monomethyl ether, or a mixed solvent thereof, to prepare a solution having a solids content of about 30 to 60 mass %.

[0082] The thickness of the photosensitive layer 20 may be 1 to 200 μm, 5 to 100 μm, 10 to 50 μm, or 10 to 30 μm.

[0083] The photosensitive element according to this embodiment may include a protective film (not shown) on the side of the photosensitive layer 20 opposite to the support film 10 (the second surface 10b side). As the protective film, it is preferable to use a film such that the adhesive strength between the photosensitive layer 20 and the protective film is smaller than the adhesive strength between the photosensitive layer 20 and the support film 10. As the protective film, a polyolefin film such as polyethylene or polypropylene can be used. The protective film may also be a polyethylene film.

[0084] The thickness of the protective film may be 5 to 100 μm, 5 to 70 μm, 10 to 60 μm, 10 to 50 μm, 15 to 40 μm, or 15 to 30 μm.

[0085] The photosensitive element of this embodiment may include an intermediate layer (not shown) between the support film and the photosensitive layer. The adhesive strength between the support film and the intermediate layer may be smaller than the adhesive strength between the intermediate layer and the photosensitive layer. The intermediate layer may be water-soluble or soluble in a developer. The intermediate layer is a layer formed using a resin composition for forming an intermediate layer, which will be described later.

[0086] The resin composition for forming an intermediate layer may contain a water-soluble resin. The inclusion of a water-soluble resin tends to improve the solubility of the intermediate layer to be formed. Furthermore, the layer separation between the intermediate layer to be formed and the photosensitive layer tends to be easily maintained for a long period of time, which tends to improve stability. Examples of water-soluble resins include polyvinyl alcohol and polyvinylpyrrolidone. The resin composition for forming an intermediate layer may contain polyvinyl alcohol, which has a low oxygen permeability coefficient and can further suppress deactivation of radicals generated by actinic rays used for exposure.

[0087] Polyvinyl alcohol can be obtained, for example, by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. The saponification degree of the polyvinyl alcohol used in this embodiment may be 50 mol% or more, 70 mol% or more, or 80 mol% or more. By using polyvinyl alcohol with a saponification degree of 50 mol% or more, the gas barrier properties of the intermediate layer can be further improved, and the resolution of the formed resist pattern tends to be further improved. In this specification, the "saponification degree" refers to a value measured in accordance with JIS K 6726:1994 (Testing methods for polyvinyl alcohol). The upper limit of the saponification degree may be 100 mol%.

[0088] The average degree of polymerization of polyvinyl alcohol may be 300 to 3500, 300 to 2500, or 300 to 1000. The average degree of polymerization of polyvinylpyrrolidone may be 10,000 to 100,000, or 10,000 to 50,000. Two or more types of polyvinyl alcohol differing in saponification degree, viscosity, degree of polymerization, modified species, etc. may be used in combination.

[0089] The resin composition for forming an intermediate layer may contain a resin soluble in a developer. The resin soluble in a developer may contain, for example, the component (A) or the component (B) used in a photosensitive resin composition. By containing a resin soluble in a developer, the adhesion between the intermediate layer and the photosensitive layer to be formed tends to be improved, and also tends to make it easier to form a photosensitive layer on the intermediate layer to be formed.

[0090] The resin composition for forming an intermediate layer may contain at least one solvent, as necessary, to improve the handleability of the resin composition or to adjust the viscosity and storage stability. Examples of solvents include water and organic solvents. Examples of organic solvents include methanol, acetone, toluene, and mixtures thereof. Methanol may be included to improve drying efficiency when forming the intermediate layer. When the resin composition for forming an intermediate layer contains a water-soluble resin, water, and methanol, the content of methanol may be 1 to 100 parts by mass, 10 to 80 parts by mass, or 20 to 60 parts by mass per 100 parts by mass of water, from the viewpoint of solubility in the water-soluble resin. The content of the water-soluble resin may be 1 to 50 parts by mass, 5 to 40 parts by mass, or 10 to 30 parts by mass per 100 parts by mass of water.

[0091] The resin composition for forming an intermediate layer may be blended with known additives such as surfactants, plasticizers, and leveling agents. Examples of leveling agents include silicone-based leveling agents. Examples of commercially available silicone-based leveling agents include Polyflow KL-401 (manufactured by Kyoeisha Chemical Co., Ltd.). When a leveling agent is contained, the content of the leveling agent may be 0.01 to 2.0 parts by mass, 0.03 to 1.5 parts by mass, or 0.05 to 1.0 parts by mass relative to 100 parts by mass of the resin composition for forming an intermediate layer, from the viewpoint of ease of forming the intermediate layer.

[0092] The surfactant may include a silicone surfactant or a fluorine surfactant from the viewpoint of improving peelability from the support film. These surfactants may be used alone or in combination of two or more. When a surfactant is contained, the content of the surfactant may be 0.01 to 1.0 parts by mass, 0.05 to 0.5 parts by mass, or 0.1 to 0.3 parts by mass relative to 100 parts by mass of the resin composition for forming an intermediate layer from the viewpoint of ease of forming the intermediate layer.

[0093] The plasticizer may contain, for example, a polyhydric alcohol compound in order to improve the ease of forming the intermediate layer. Examples of the plasticizer include glycerins such as glycerin, diglycerin, and triglycerin; (poly)alkylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, and polypropylene glycol; and trimethylolpropane. These plasticizers may be used alone or in combination of two or more.

[0094] The thickness of the intermediate layer is not particularly limited, but may be 12 μm or less, 10 μm or less, or 8 μm or less from the viewpoint of developability, and may be 1.0 μm or more, 1.5 μm or more, or 2.0 μm or more from the viewpoint of ease of forming the intermediate layer and resolution.

[0095] [Method for forming a resist pattern] The method for forming a resist pattern according to this embodiment includes a lamination step of laminating the photosensitive layer 20 of the photosensitive element 1 on a substrate in the order of the photosensitive layer and the support film; an exposure step of irradiating predetermined portions of the photosensitive layer 20 with actinic rays through the support film 10 to form photocured portions; and a development step of removing areas of the photosensitive layer 20 other than the photocured portions.

[0096] In the lamination step, for example, the photosensitive layer and support film of the photosensitive element are laminated on the substrate in this order. In the lamination step, a method for laminating the photosensitive layer 20 on the substrate includes, for example, removing a protective film when present on the photosensitive layer 20, and then heating the photosensitive layer 20 to about 70 to 130°C while pressing it onto the substrate at a pressure of about 0.1 to 1 MPa. In the lamination step, lamination under reduced pressure is also possible. The surface of the substrate on which the photosensitive layer 20 is laminated is usually a metal surface, but is not particularly limited. Furthermore, the substrate may be preheated to further improve lamination properties.

[0097] Next, in the exposure step, for example, actinic rays are irradiated onto predetermined portions of the photosensitive layer 20 through the support film 10 to form photocured portions in the photosensitive layer 20. Examples of exposure methods include a method of irradiating actinic rays imagewise through a negative or positive mask pattern called artwork (mask exposure method), a method of irradiating actinic rays imagewise by a projection exposure method, and a method of irradiating actinic rays imagewise by a direct writing exposure method such as an LDI (Laser Direct Imaging) exposure method or a DLP (Digital Light Processing) exposure method.

[0098] As the light source of the actinic rays, a known light source can be used, for example, a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, a gas laser such as an argon laser, a solid-state laser such as a YAG laser, a semiconductor laser, or the like, which effectively emits ultraviolet light or visible light.

[0099] From the viewpoint of improving adhesion, post-exposure baking (PEB) may be performed after exposure and before development. The temperature when performing PEB may be 50 to 100° C. As the heater, a hot plate, a box-type dryer, a heating roll, or the like may be used.

[0100] In the development step, at least a portion of the photosensitive layer other than the photocured portion is removed from the substrate, thereby forming a resist pattern on the substrate.

[0101] In the development step, the support film 10 is peeled off and removed from the photosensitive layer 20, and then the regions of the photosensitive layer other than the photocured portions are removed. In the development step, the unexposed portions (unphotocured portions) of the photosensitive layer 20 are removed and developed by, for example, wet development using a developer such as an alkaline aqueous solution, a water-based developer, or an organic solvent, or dry development, to produce a resist pattern.

[0102] Examples of alkaline aqueous solutions include 0.1 to 5% by mass sodium carbonate solution, 0.1 to 5% by mass potassium carbonate solution, and 0.1 to 5% by mass sodium hydroxide solution. The pH of the alkaline aqueous solution is preferably in the range of 9 to 11. The temperature of the alkaline aqueous solution is adjusted according to the developability of the photosensitive layer 20. The alkaline aqueous solution may also contain a surfactant, an antifoaming agent, an organic solvent, etc. Examples of development methods include dipping, spraying, brushing, and scrubbing.

[0103] As a treatment after the development step, if necessary, heating at about 60 to 250°C or 0.2 to 10 J / cm ２ The resist pattern may be further hardened by exposing it to light.

[0104] [Method for manufacturing a printed wiring board] The method for manufacturing a printed wiring board according to this embodiment includes a step of etching or plating a substrate having a resist pattern formed by the above-described method for forming a resist pattern, where the etching or plating of the substrate can be performed by etching or plating the surface of the substrate by a known method using the resist pattern as a mask.

[0105] Examples of etching solutions used for etching include cupric chloride solutions, ferric chloride solutions, and alkaline etching solutions. Examples of plating solutions include copper plating, solder plating, nickel plating, and gold plating.

[0106] After etching or plating, the resist pattern can be stripped, for example, with an aqueous solution that is more strongly alkaline than the aqueous solution used for development. Examples of the strongly alkaline aqueous solution include a 1 to 10% by mass aqueous solution of sodium hydroxide and a 1 to 10% by mass aqueous solution of potassium hydroxide. Examples of stripping methods include immersion and spraying. The printed wiring board on which the resist pattern is formed may be a multilayer printed wiring board and may have small-diameter through-holes.

[0107] When plating is performed on a substrate having an insulating layer and a conductor layer formed on the insulating layer, it is necessary to remove the conductor layer other than the resist pattern. Examples of this removal method include a method in which the resist pattern is stripped off and then lightly etched, and a method in which solder plating or the like is performed following the plating, and then the resist pattern is stripped off to mask the wiring portion with solder, and then the conductor layer is treated with an etching solution that can etch only the portion not masked with solder.

[0108] The present disclosure will be described in more detail below using examples and comparative examples, but the present invention is not limited to these examples.

[0109] [Photosensitive Resin Composition] Photosensitive resin compositions were prepared by mixing the components in the amounts (parts by mass) shown in Table 1. Details of each component shown in Table 1 are as follows.

[0110] (Binder polymer) A-1: ​​ethylene glycol monomethyl ether / toluene solution (solid content: 40% by mass) of a copolymer of methacrylic acid / styrene / benzyl methacrylate / 2-hydroxyethyl methacrylate (mass ratio: 27 / 50 / 20 / 3, Mw: 35,000, acid value: 176 mg KOH / g)

[0111] The Mw of the binder polymer was measured by gel permeation chromatography (GPC) under the following conditions and calculated by conversion using a standard polystyrene calibration curve. Pump: L-2130 (Hitachi High-Technologies Corporation) Detector: L-2490 RI (Hitachi High-Technologies Corporation) Column oven: L-2350 (Hitachi High-Technologies Corporation) Column: Gelpack GL-R440 + Gelpack GL-R450 + Gelpack GL-R400M (total of 3) (Resonac Corporation) Column size: 10.7 mm ID x 300 mm Eluent: tetrahydrofuran Sample concentration: 10 mg / 2 mL Injection volume: 200 μL Flow rate: 2.05 mL / min Measurement temperature: 25°C

[0112] The acid value of the binder polymer was measured by the following procedure. First, the binder polymer was weighed in an Erlenmeyer flask. Next, a mixed solvent (mass ratio: toluene / methanol = 70 / 30) was added to dissolve the binder polymer, and then a phenolphthalein solution was added as an indicator. The acid value was then determined by titration with a 0.1 mol / L (N / 10) potassium hydroxide solution (alcohol solution).

[0113] (Photopolymerizable Compounds) FA-321M: EO-modified bisphenol A dimethacrylate (manufactured by Resonac Corporation, number of EO groups: 10 (average value)) FA-024M: polyalkylene glycol dimethacrylate (manufactured by Resonac Corporation, number of EO groups: 12 (average value), number of PO groups: 4 (average value)) BP-2EM: 2,2-bis(4-(methacryloxydiethoxy)phenyl)propane (manufactured by Kyoeisha Chemical Co., Ltd.) (Photopolymerization Initiator) B-CIM: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole (manufactured by Hodogaya Chemical Co., Ltd.) (Sensitizer) PZ-501D: 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline (manufactured by Nippon Chemical Industry Co., Ltd.) (Polymerization Inhibitor) TBC: 4-tert-butylcatechol (manufactured by DIC Corporation) LA-7RD: 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (manufactured by ADEKA Corporation) (dye) MKG: Malachite Green (manufactured by Osaka Organic Chemical Industry Ltd.) (color former) LCV: Leuco Crystal Violet (manufactured by Yamada Chemical Industry Co., Ltd.)

[0114]

[0115] [Support Film] Three-layer biaxially oriented PET films (thickness: 16 μm), S1 to S5, were prepared as support films for the photosensitive elements.

[0116] (Particle size and number of lubricant particles) Using a confocal microscope (manufactured by Lasertec Corporation, product name "Hybrid Laser Microscope OPTELICS HYBRID"), a particle size of 0.0225 mm on the first surface and the second surface of the support film was measured. ２The number of lubricants contained in an area of ​​0.150 mm x 0.150 mm was measured. Images were acquired under the conditions of a lens numerical aperture (Na) of 0.8, a magnification of 50x, and a digital zoom of 2x, as shown in Table 2 below, and the size and number of lubricants were calculated from the pixels in the image. The results are shown in Table 3. S1 to S5 contained lubricants with particle sizes of 2.0 μm or less.

[0117]

[0118] (Type of Lubricant) Each support film was cast with resin and processed into thin sections using a microtome. The cross section of each support film was observed using a transmission electron microscope (STEM) (manufactured by JEOL Ltd., product name "JEM-2100F"), and the component elements contained on the first and second surfaces were measured using an energy dispersive X-ray detector (EDX) (manufactured by JEOL Ltd., product name "JED-2300"). S1 and S2 contained only an organic lubricant (organic particles containing a styrene-based resin) on the first surface, and an organic lubricant and an inorganic lubricant (inorganic particles containing silicon and aluminum) on the second surface. S3, S4, and S5 contained an organic lubricant and an inorganic lubricant on the first and second surfaces.

[0119] (Surface Roughness) Using a scanning interference microscope, the surface roughness of the first surface and the second surface of each support film was measured, and the ten-point average roughness Rz was calculated.

[0120] [Photosensitive element] A solution of the photosensitive resin composition was uniformly applied onto the first layer of the support film using a comma coater. Subsequently, the coating was dried for 2 minutes in a hot air convection dryer at 100°C to form a photosensitive layer with a thickness of 15 μm. Next, a PE film (trade name "NF-15A", manufactured by Tamapoly Co., Ltd., thickness: 28 μm) was laminated onto the photosensitive layer as a protective film to produce a photosensitive element.

[0121] [Evaluation] (Preparation of Laminate) Substrate a was prepared by sputtering titanium to 10 nm on a PET film (manufactured by Toyobo Co., Ltd., trade name "Cosmoshine A4160", thickness: 125 μm) and then sputtering copper to 100 nm. After heating this substrate a to 80°C, the photosensitive element was laminated so that the photosensitive layer was in contact with the copper layer while peeling off the protective film of the photosensitive element. This resulted in a laminate having substrate a, photosensitive layer, and support film in this order in the stacking direction. Lamination was performed using a heat roll at 110°C, with a pressure of 0.4 MPa and a roll speed of 1.5 m / min.

[0122] (Formation of Resist Pattern) Using a phototool having a 41-step tablet, a glass chrome-type phototool having a wiring pattern with a line width / space width of 20 / 20 to 1.0 / 1.0 (unit: μm) as a negative for adhesion evaluation, and a high-resolution projection exposure machine (manufactured by Ushio Inc., product name "UX-2240") having a high-pressure mercury lamp, the photosensitive layer of the laminate was exposed at an irradiation energy amount such that the number of remaining steps after development of the 41-step tablet was 11. Next, the support film was peeled off, and the unexposed portions were removed by spray development with a 1 mass % aqueous sodium carbonate solution at 30°C, forming a resist pattern with a line width / space width of 5.0 / 5.0 (unit: μm).

[0123] A 73 μm x 55 μm area of ​​a substrate on which a resist pattern was formed was imaged using a NEXIV VMZ-R4540 (trade name, manufactured by Nikon Corporation). Scanning measurements using the NEXIV VMZ-R4540 identified the contour of the formed resist pattern, and the coordinates of the contour of the resist pattern were measured for six lines of the resist pattern. Coordinate measurements were performed on 260 points, spaced 52 μm apart at 0.2 μm intervals, on one side of the contour and the other side of the contour of the line. These measurements were also performed at three locations on each of the six lines. This resulted in a total of 9,360 coordinates being measured. The contour variation (3σ) of the resist pattern was calculated based on the measured coordinates of the 9,360 points. The contour 3σ is also known as LER (Line Edge Roughness). The smaller the value, the finer the resist pattern formed.

[0124]

[0125] 1...photosensitive element, 10...support film, 10a...first surface, 10b...second surface, 12...first lubricant layer, 14...second lubricant layer, 16...base layer, 20...photosensitive layer.

Claims

1. A photosensitive layer is provided on a first surface of a support film containing a lubricant, wherein the support film is composed of a first lubricant layer, a base layer, and a second lubricant layer, and the first surface of the support film is provided with the first lubricant layer, and the second surface of the support film is provided with the second lubricant layer, wherein the second lubricant layer contains an organic lubricant but does not contain an inorganic lubricant, and the number of organic lubricants with a particle size of 0.8 μm or more contained on the second surface is 0.0225 mm ２ 2 or more per surface; and the surface roughness Rz of the first surface and the second surface is less than 100 nm.

2. The number of organic lubricants having a particle size of 0.8 μm or more contained in the second surface is 0.0225 mm ２ The photosensitive element of claim 1 , wherein the number of nanoparticles per nanoparticle is 100 or less.

3. The total number of lubricants contained in the second surface is 0.0225 mm ２ The photosensitive element of claim 1 , wherein the number of nanoparticles per nanoparticle is 300 or less.

4. The number of lubricants having a particle size of 0.8 μm or more contained in the first surface is 0.0225 mm ２ The photosensitive element of claim 1 , wherein the number of nanoparticles per nanoparticle is 100 or less.

5. The total number of lubricants contained in the first surface is 0.0225 mm ２ The photosensitive element of claim 1 having a surface area of ​​1000 or less per square inch.

6. The photosensitive element of claim 1, wherein the support film is a biaxially oriented polyester film.

7. A method for forming a resist pattern, comprising: a laminating step of laminating the photosensitive element according to any one of claims 1 to 6 on a substrate in the order of a photosensitive layer and a support film; an exposure step of irradiating predetermined parts of the photosensitive layer with active light through the support film to form photocured parts; and a development step of removing areas of the photosensitive layer other than the photocured parts.

8. A method for manufacturing a printed wiring board, comprising the step of etching or plating a substrate having a resist pattern formed by the method for forming a resist pattern according to claim 7 to form a conductor pattern.

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