Photosensitive element, method for forming a resist pattern, and method for manufacturing a printed circuit board.

Abstract

One aspect of the present disclosure relates to a photosensitive element comprising a lubricant-containing support film, and a photosensitive layer that is formed on a first surface of the support film, wherein the quantity of lubricant having a particle size of at least 0.8 μm and contained in a second surface of the support film on the reverse side from the first surface is at most 80 per 0.0225 mm2.

Description

[Technical Field]

[0001] This disclosure relates to a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a printed circuit board. [Background technology]

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

[0003] Printed circuit boards are manufactured using photosensitive elements, for example, by the following procedure. 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 photocurable area. At this time, the support film is peeled off before or after exposure. After that, the areas of the photosensitive layer other than the photocurable area are removed with a developer to form a resist pattern. Next, the resist pattern is used as a resist and subjected to etching or plating to form a conductor pattern, and finally the photocurable area (resist pattern) of the photosensitive layer is peeled off (removed).

[0004] Support films used for photosensitive elements include support films having a specific haze value and support films having a specific lubricant particle size (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2001-13681 [Patent Document 2] Japanese Patent Publication No. 2014-74764 [Overview of the project] [Problems that the invention aims to solve]

[0006] With the increasing resolution required for circuit formation in recent years, miniaturization of conductor patterns is demanded, and this also necessitates miniaturization of resist patterns used to form these conductor patterns. However, lubricants contained in the support film can scatter light during exposure, which can cause roughness (jaggedness) in the outline of the resist pattern. In particular, lubricants with large particle sizes scatter light over a wide area, making it easier for the outline of the resist pattern to become rough.

[0007] The present disclosure aims to provide a photosensitive element that is excellent in forming fine resist patterns, a method for forming resist patterns using the photosensitive element, and a method for manufacturing a printed circuit board. [Means for solving the problem]

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

[0009] [1] A support film containing a lubricant and a photosensitive layer formed on a first surface of the support film, wherein the number of lubricants with a particle size of 0.8 μm or more contained on a second surface of the support film opposite to the first surface is 0.0225 mm 2 A photosensitive element with a value of 80 or less per unit. [2] The total number of lubricants contained in the second surface is 0.0225 mm 2 A photosensitive element as described in [1] above, wherein the value is 2000 or less per unit. [3] The photosensitive element according to [1] or [2] above, wherein the value obtained by dividing the number of lubricants with a particle size of 0.8 μm or more contained in the second surface by the total number of lubricants contained in the second surface is 0.20 or less. [4] The number of lubricants with a particle size of 0.8 μm or larger contained in the first surface is 0.0225 mm 2 A photosensitive element as described in any of the above [1] to [3], having a value of 200 or less per unit. [5] A photosensitive element according to any one of [1] to [4] above, wherein the average particle size of the lubricant contained in the first surface and the second surface is 0.3 μm or more and 1.0 μm or less. [6] The photosensitive element according to any one of [1] to [5] above, wherein the support film is a biaxially oriented polyester film. [7] The photosensitive element according to any of [1] to [6] above, wherein the support film does not contain lubricants with a particle size greater than 3.0 μm. [8] A method for forming a resist pattern, comprising: a lamination step of laminating the photosensitive elements described in any of [1] to [7] above onto a substrate in the order of a photosensitive layer and a support film; an exposure step of irradiating a predetermined portion of the photosensitive layer with an active light through the support film to form a photocurable portion; and a development step of removing the region of the photosensitive layer other than the photocurable portion. [9] A method for manufacturing a printed wiring board, comprising the step of etching or plating a substrate having a resist pattern formed by the resist pattern formation method described in [8] above to form a conductor pattern. [Effects of the Invention]

[0010] According to this disclosure, it is possible to provide a photosensitive element that is excellent in forming fine resist patterns, a method for forming resist patterns using the photosensitive element, and a method for manufacturing a printed circuit board. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view showing one embodiment of a photosensitive element. [Modes for carrying out the invention]

[0012] The following describes in detail the forms for implementing this disclosure. However, this disclosure is not limited to the following embodiments.

[0013] In this specification, a numerical range indicated by "~" means a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. "A or more" of a numerical range means A and a range exceeding A. "A or less" of a numerical range means A and a range less than A. In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value of a numerical range at a certain step can be arbitrarily combined with the upper limit value or the lower limit value of a numerical range at another step. In the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0014] In this specification, "A or B" means either A or B, or both may be included. The materials exemplified in this specification can be used alone or in combination of two or more, unless otherwise specified. The content of each component in the composition means the total amount of the plurality of substances present in the composition when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified. The terms "layer" and "film" include, when observed as a plan view, not only the structure formed over the entire surface but also the structure formed partially. The term "step" includes not only an independent step but also a step in which, even if it cannot be clearly distinguished from other steps, the intended action of the step is achieved.

[0015] In this specification, "(meth)acrylate" means at least one of acrylate and the corresponding methacrylate. The same applies to other similar expressions such as "(meth)acrylic acid". "EO" represents ethylene oxide, and a compound "modified with EO" means a compound having an oxyethylene group. "PO" represents propylene oxide, and a compound "modified with PO" means a compound having an oxypropylene group. "Solid content" refers to the non-volatile content excluding volatile substances such as water and solvents contained in the photosensitive resin composition, and indicates the components that remain without volatilizing when the resin composition is dried, and also includes components in a liquid state, a syrup state, and a wax state 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 the first surface of the support film. The number of lubricants having a particle size of 0.8 μm or more contained in the second surface opposite to the first surface of the support film is 0.0225 mm 2 per 80 or less.

[0017] FIG. 1 is a schematic cross-sectional view showing an embodiment of the photosensitive element. The photosensitive element 1 according to this embodiment includes a support film 10 and a photosensitive layer 20 as shown in FIG. 1. The photosensitive layer 20 is provided on the first surface 10a of the support film 10. The support film 10 has a second surface 10b on the side 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 surfaces of the support film. By reducing the lubricant having a size of 0.8 μm or more among the lubricants contained in the second surface 10b of the support film that does not contact the photosensitive layer, the roughness of the contour of the resist pattern can be reduced.

[0019] The lubricant is not particularly limited as long as it does not inhibit the light transmittance of the support film and is a component used in the production of the polyester film, and may be an inorganic lubricant or an organic lubricant. Examples of the inorganic lubricant include inorganic particles containing, as inorganic components, silica, calcium carbonate, alumina, aluminum silicate, mica, clay, talc, wollastonite, kaolin, zinc oxide, barium sulfate, calcium phosphate, calcium, magnesium, barium, zinc, manganese, and the like. Examples of the organic lubricant include crosslinked polymers such as polystyrene, polymethyl methacrylate, polyimide, polyolefin, modified polyolefin, and silicone resin.

[0020] The number of lubricants having a particle size of 0.8 μm or more contained in the second surface 10b of the support film is 0.0225 mm from the viewpoint of further reducing the roughness of the contour of the resist pattern. 2It may be 75 or less, 70 or less, 65 or less, or 60 or less. The number of lubricants according to this embodiment is the average value per 0.0225 mm 2 (0.150 mm × 0.150 mm). Note that the lubricants with a particle size of 0.8 μm or more include aggregates of lubricants with a particle size of 0.8 μm or less.

[0021] The support film according to this embodiment may contain lubricants with a particle size of less than 0.8 μm. The total number of lubricants contained in the second surface 10b (the number of lubricants with a particle size of 0.8 μm or more and the number of lubricants with a particle size of less than 0.8 μm) is, from the viewpoint of further enhancing the slipperiness of the support film, per 0.0225 mm 2 It may be 2500 or less, 2200 or less, 2000 or less, or 1800 or less, and may also be 10 to 1800, 20 to 1600, 30 to 1400, or 40 to 1200.

[0022] From the viewpoint of further enhancing the slipperiness of the support film, the value obtained by dividing the number of lubricants with a particle size of 0.8 μm or more contained in the second surface 10b by the total number of lubricants contained in the second surface 10b may be 0.20 or less, 0.18 or less, 0.16 or less, 0.14 or less, or 0.12 or less.

[0023] The number of lubricants with a particle size of 0.8 μm or more contained in the second surface 10b is preferably less than the number of lubricants with a particle size of 0.8 μm or more contained in the first surface 10a. The number of lubricants with a particle size of 0.8 μm or more contained in the first surface 10a is, from the viewpoint of suppressing resist defects, per 0.0225 mm 2 It may be 400 or less, 300 or less, 200 or less, or 180 or less, and may also be 10 to 400, 15 to 300, 20 to 200, or 25 to 180.

[0024] The total number of lubricants contained in the first surface 10a is, from the viewpoint of further enhancing the slipperiness of the support film, per 0.0225 mm 2 It may also be 100 to 1600, 150 to 1500, 155 to 1400, or 160 to 1200.

[0025] The support film according to this embodiment preferably does not contain lubricants with a particle size exceeding 3.0 μm, from the viewpoint of suppressing resist defects. The upper limit of the size of lubricants with a particle size of 0.8 μm or more included in the first surface 10a and the second surface 10b may be 3.0 μm or less, 2.5 μm or less, 2.0 μm or less, or 1.5 μm or less. The lower limit of the size of lubricants with a particle size of 0.8 μm or more included in the first surface 10a and the second surface 10b may be 0.8 μm or more, 0.9 μm or more, 1.0 μm or more, or 1.1 μm or more, from the viewpoint of improving handling performance.

[0026] The average particle size of the lubricant contained in 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 handling performance, and may be 1.0 μm or less, 0.8 μm or less, or 0.6 μm or less from the viewpoint of suppressing resist defects.

[0027] The size and number of lubricants contained in the support film can be measured using a confocal microscope. A confocal microscope such as the OPTELICS HYBRID (Lasertec Corporation, product name) can be used. Confocal microscopy is a measurement method that detects reflected light from the object being observed using a light-receiving unit. When the object is in focus, a strong reflected light is obtained, and the light intensity is observed to be high (often observed as white). When the object is out of focus, the light intensity is observed to be low (often observed as black).

[0028] The numerical aperture (Na) of the objective lens used for observation may be 0.8 from the viewpoint of facilitating accurate and efficient observation. When the numerical aperture is 0.8, compared to when the numerical aperture is greater than 0.8, contact between the lens and the object being observed, which can cause contamination of the microscope, is less likely to occur. Furthermore, excessively high magnification is suppressed, thus preventing a decrease in the amount of light in the field of view and a decrease in the detection level. In addition, when the numerical aperture (Na) is 0.8, compared to when the numerical aperture is less than 0.8, the decrease in resolution is suppressed, making it easier to detect the size of the object being observed with less error, thus facilitating accurate measurement.

[0029] In confocal microscopy observations, the measurement magnification may be 50x, and the software digital zoom may be 2x. When the measurement magnification is 50x, the decrease in light intensity in the field of view is suppressed and the decrease in detection level is suppressed more easily compared to when the measurement magnification is greater than 50x, and the size of defects can be measured more accurately compared to when the measurement magnification is less than 50x. When the digital zoom is 2x, the decrease in light intensity in the field of view is suppressed and the decrease in detection level is suppressed more easily compared to when the digital zoom is 1x (no setting).

[0030] Examples of materials used to construct the support film include polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene-2,6-naphthalate (PEN); and polyolefins such as polypropylene and polyethylene. The support film may be a polyester film or a PET film, from the viewpoint of easily suppressing the occurrence of defects in the resist. The support film is a light-transmitting film and may be a transparent resin film.

[0031] The support film can be a multilayer film having a lubricant layer. The support film may have a polyester film and a lubricant layer disposed on at least one surface of the polyester film. The lubricant layer can be formed using known methods such as a roll coater, flow coater, spray coater, curtain flow coater, dip coater, or slit die coater. It is preferable to use a biaxially oriented polyester film with a two- or three-layer structure as the support film, and more preferable to use a biaxially oriented PET film with a three-layer structure.

[0032] 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 improving the operability when laminating the photosensitive element onto the substrate and the operability when forming the 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 degree of cloudiness. The haze value of the support film can be measured using a commercially available cloudiness meter (turbidimeter; for example, product name "NDH-5000" manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with the method specified in JIS K 7105.

[0033] The light transmittance of the support film (for example, the light transmittance over the entire wavelength range of 380 to 780 nm) may be within 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 viewpoints, the light transmittance of the support film may be between 80% and 95%. The light transmittance of the support film can be measured using a commercially available haze meter (for example, product name "NDH-5000" manufactured by Nippon Denshoku Industries Co., Ltd.).

[0034] The thickness of the support film, or the polyester film, may be within the following ranges. From the viewpoint of making it difficult for the support film to tear when peeling it from the photosensitive element, the thickness 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 making it easier to secure a focus margin during exposure, the thickness 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 these viewpoints, the thickness may be 5 to 200 μm, 11 to 100 μm, 12 to 50 μm, or 15 to 40 μm.

[0035] 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)).

[0036] Examples of constituent materials for the binder polymer of component (A) include acrylic resin, styrene resin, epoxy resin, amide resin, amide epoxy resin, alkyd resin, and phenolic resin. Component (A) may contain acrylic resin from the viewpoint of easily obtaining good alkali developability. Conventional binder polymers used in photosensitive resin compositions can be used as component (A).

[0037] (A) Component can be produced, for example, by radical polymerization of a polymerizable monomer. Examples of polymerizable monomers include styrene or styrene derivatives, acrylamides such as diacetone acrylamide, acrylonitrile, vinyl alcohol ethers such as vinyl-n-butyl ether, alkyl (meth)acrylates, benzyl (meth)acrylates, hydroxyalkyl (meth)acrylates, tetrahydrofurfuryl (meth)acrylates, dimethylaminoethyl (meth)acrylates, diethylaminoethyl (meth)acrylates, and glycidyl (meth)acrylates. Examples include tel, 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 acid anhydride, maleic acid monoesters such as maleic acid monomethyl, maleic acid monoethyl, maleic acid monoisopropyl, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. Polymerizable monomers can be used individually or in combination of two or more.

[0038] Component (A) may have a carboxyl group from the viewpoint of alkali developability. Component (A) having a carboxyl group can be produced, for example, by radical polymerization of a polymerizable monomer having a carboxyl group with another polymerizable monomer. The polymerizable monomer having a carboxyl group may be (meth)acrylic acid or methacrylic acid.

[0039] From the standpoint of improving alkali developability and alkali resistance in a balanced manner, the content of structural units based on polymerizable monomers having carboxyl groups may be 10-50% by mass, 15-40% by mass, or 20-35% by mass, based on the total amount of component (A). When the carboxyl group content is 10% by mass or more, alkali developability tends to improve, and when it is 50% by mass or less, alkali resistance tends to be excellent.

[0040] Component (A) may have structural units based on styrene or styrene derivatives from the viewpoint of adhesion and peelability. Styrene derivatives are polymerizable compounds in which a hydrogen atom at the α-position or aromatic ring of styrene is substituted, such as vinyltoluene and α-methylstyrene. The content of structural units based on styrene or styrene derivatives in component (A) may be 10-60% by mass, 15-50% by mass, 35-50% by mass, or 40-50% by mass. When the content is 10% by mass or more, adhesion tends to improve, and when it is 60% by mass or less, the size of the peeled-off pieces during development can be suppressed, and the time required for peeling tends to be reduced.

[0041] Component (A) may have structural units based on benzyl (meth)acrylate for the purpose of improving resolution. The content of structural units derived from benzyl (meth)acrylate in component (A) may be 10 to 40% by mass, 15 to 35% by mass, or 20 to 30% by mass.

[0042] Component (A) may have structural units based on alkyl (meth)acrylate for the purpose of improving plasticity. Examples of alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate.

[0043] (A) Component may have a structural unit based on hydroxyalkyl (meth)acrylate from the viewpoint of further improving resolution and adhesion. Examples of hydroxyalkyl (meth)acrylates include hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxypentyl (meth)acrylate, hydroxyhexyl (meth)acrylate, etc. In addition, if the alkyl part of the hydroxyalkyl (meth)acrylate unit has 3 or more carbon atoms, it may have a branched structure.

[0044] The weight-average molecular weight (Mw) of component (A) may be 10,000 or more, 15,000 or more, 20,000 or more, or 25,000 or more from the viewpoint of excellent adhesion of the resist pattern, and may be 100,000 or less, 80,000 or less, 70,000 or less, or 60,000 or less from the viewpoint of suitable development. The dispersion (Mw / Mn) of component (A) may be, for example, 1.0 or more, 1.5 or more, or 1.8 or more, and may be 3.0 or less, 2.5 or less, or 2.0 or less from the viewpoint of further improving adhesion and resolution.

[0045] The weight-average molecular weight (Mw) and dispersion (Mw / Mn) used herein can be obtained by measuring them by gel permeation chromatography (GPC) and converting them using a calibration curve for standard polystyrene.

[0046] The acid value of component (A) may be 60 mg KOH / g or more, 80 mg KOH / g or more, 90 mg KOH / g or more, or 100 mg KOH / g or more from the viewpoint of suitable development, and may be 250 mg KOH / g or less, 230 mg KOH / g or less, 210 mg KOH / g or less, or 200 mg KOH / g or less from the viewpoint of improving the adhesion (developer resistance) of the resist pattern. The acid value of component (A) can be adjusted by the content of structural units constituting component (A) (for example, structural units derived from (meth)acrylic acid).

[0047] Component (A) can be used alone or in combination of two or more. Examples of components (A) used in combination of two or more include two or more binder polymers consisting of different polymerizable monomers, two or more binder polymers with different Mw values, and two or more binder polymers with different degrees of dispersion.

[0048] 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 per 100 parts by mass of the total amount of component (A) and component (B) described later. When the content of component (A) is within this range, the strength of the photo-cured portion of the photosensitive layer is better.

[0049] (B) As the photopolymerizable compound, a compound having at least one ethylenically unsaturated bond in its molecule can be used. Component (B) can be used alone or in combination of two or more.

[0050] (B) The ethylenically unsaturated bond in component (B) is not particularly limited as long as it is photopolymerizable. Examples of ethylenically unsaturated bonds include α,β-unsaturated carbonyl groups such as (meth)acryloyl groups. Examples of photopolymerizable compounds having α,β-unsaturated carbonyl groups 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 urethane bonds, nonylphenoxypolyethylene oxyacrylates, (meth)acrylates having a phthalic acid skeleton, and alkyl (meth)acrylates.

[0051] 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 having a block structure of ethylene oxide (EO) groups, and "PO-modified" means having a block structure of propylene oxide (PO) groups.

[0052] Component (B) may include polyalkylene glycol di(meth)acrylate from the viewpoint of improving the flexibility of the resist pattern. The polyalkylene glycol di(meth)acrylate may have at least one of an EO group and a PO group, or it 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 group and the PO group may be present in a continuous block-like manner or randomly. Furthermore, the PO group may be either an oxy-n-propylene group or an oxyisopropylene group. In the case of a (poly)oxyisopropylene group, the secondary carbon of the propylene group may be bonded to the oxygen atom, or the primary carbon may be bonded to the oxygen atom.

[0053] Examples of commercially available polyalkylene glycol di(meth)acrylates include FA-023M (manufactured by Resonaq Corporation), FA-024M (manufactured by Resonaq Corporation), and NK ester HEMA-9P (manufactured by Shin Nakamura Chemical Industry Co., Ltd.).

[0054] Component (B) may include a (meth)acrylate having a urethane bond, from the viewpoint of improving the flexibility of the resist pattern. Examples of (meth)acrylates having a urethane bond include addition reaction products of a (meth)acrylic monomer having an OH group at the β position and a diisocyanate (isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, 1,6-hexamethylene diisocyanate, etc.), tris((meth)acryloxytetraethylene glycol isocyanate)hexamethylene isocyanurate, EO-modified urethane di(meth)acrylate, and EO,PO-modified urethane di(meth)acrylate.

[0055] Examples of commercially available EO-modified urethane di(meth)acrylate include "UA-11" and "UA-21EB" (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.). An example of a commercially available EO,PO-modified urethane di(meth)acrylate is "UA-13" (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.).

[0056] Component (B) may include a (meth)acrylate compound having a skeleton derived from dipentaerythritol or pentaerythritol, from the viewpoint of facilitating the formation of thick resist patterns and improving resolution and adhesion in a balanced manner. The (meth)acrylate compound having a skeleton derived from dipentaerythritol or pentaerythritol preferably has four or more (meth)acryloyl groups, and may be dipentaerythritol penta(meth)acrylate or dipentaerythritol hexa(meth)acrylate.

[0057] (B) The compound 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 it may have both an EO group and a PO group. As such a compound, dipentaerythritol (meth)acrylate having an EO group can be used. A commercially available product of dipentaerythritol (meth)acrylate having an EO group is, for example, DPEA-12 (manufactured by Nippon Kayaku Co., Ltd.).

[0058] From the viewpoint of improving resolution and peelability after curing, component (B) may contain bisphenol-type (meth)acrylate, and among bisphenol-type (meth)acrylates, it may contain bisphenol A-type (meth)acrylate. Examples of bisphenol A-type (meth)acrylate 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.

[0059] Commercially available examples include 2,2-bis(4-(meth)acryloxydiethoxy)phenyl)propane, such as BPE-200 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), and 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane, such as BPE-500 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) and FA-321M (manufactured by Resonac Co., Ltd.).

[0060] Examples of nonylphenoxypolyethylene oxyacrylates include nonylphenoxytetraethylene oxyacrylate, nonylphenoxypentaethylene oxyacrylate, nonylphenoxyhexaethylene oxyacrylate, nonylphenoxyheptaethylene oxyacrylate, nonylphenoxyoctaethylene oxyacrylate, nonylphenoxynonaethylene oxyacrylate, nonylphenoxydecaethylene oxyacrylate, and nonylphenoxyundaethylene oxyacrylate.

[0061] Examples of (meth)acrylates having a phthalate 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 Resonaq Corporation).

[0062] The photopolymerization initiator, which is component (C), is not particularly limited as long as it can polymerize component (B), and can be appropriately selected from commonly used photopolymerization initiators. Component (C) can be used alone or in combination of two or more types.

[0063] Examples of component (C) include imidazole compounds, aromatic ketones (excluding compounds that fall under the category of benzophenone compounds), quinone compounds, benzoin compounds, acridine compounds, N-phenylglycine compounds, and benzyl derivatives.

[0064] Examples of imidazole compounds 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, and 2,2'-bi Examples include su-(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.

[0065] Examples of acridine compounds 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 include bis(9-acridinyl)alkanes such as 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, as well as 1,3-bis(9-acridinyl)-2-oxapropane, 1,3-bis(9-acridinyl)-2-thiapropane, and 1,5-bis(9-acridinyl)-3-thiapentane.

[0066] 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 benzyldimethylketal.

[0067] The content 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 per 100 parts by mass of the total amount of components (A) and (B). When the content of component (C) is 0.1 parts by mass or more, the photosensitivity, resolution and adhesion tend to improve, and when it is 10 parts by mass or less, the resist pattern formation properties tend to be superior.

[0068] The photosensitive resin composition according to this embodiment may further contain a photosensitizer as component (D). By including component (D), the absorption wavelength of the active light used for exposure can be effectively utilized. Component (D) can be used alone or in combination of two or more types.

[0069] 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. The sensitizer may contain at least one selected from the group consisting of pyrazoline compounds, benzophenone compounds, anthracene compounds, and coumarin compounds, from the viewpoint of easily suppressing the occurrence of resist defects, easily shortening the minimum development time, and easily obtaining good sensitivity, resolution, and adhesion.

[0070] Examples of pyrazoline compounds 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, and 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)-pyrazoline, 1-(4-methoxyphenyl)-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, 1-(4-isopropylphenyl)-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)-Pyrazolin, 1-(4-Methoxyphenyl)-3-(2,6-Dimethoxystyryl)-5-(2,6-Dimethoxyphenyl)-Pyrazolin, 1-(4-Methoxyphenyl)-3-(2,5-Dimethoxystyryl)-5-(2,5-Dimethoxyphenyl)-Pyrazolin, 1-(4-Methoxyphenyl)-3-(2,3-Dimethoxystyryl)-5-(2,3-Dimethoxyphenyl)-Pyrazolin, 1-(4-Methoxyphenyl)-3-(2,4-Dimethoxystyryl)-5-(2 ,4-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,5-dimethoxystyryl)-5 -(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, 1-(4-tert-butylphenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(3,4-dimethoxystyryl)-5- (3,4-dimethoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-(4-isopropylphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, and 1-(4-isopropylphenyl)-3-(2,4-dimethoxystyryl)-5-(2,Examples include 4-dimethoxyphenyl)-pyrazoline. The sensitizer may contain 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline, from the viewpoint of easily obtaining good resolution and adhesion.

[0071] Examples of benzophenone compounds include benzophenone; N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone (also known as Michler's ketone), N,N,N',N'-tetraethyl-4,4'-diaminobenzophenone, and other N,N,N',N'-tetraalkyl-4,4'-diaminobenzophenones; and dialkylaminobenzophenones such as 4-methoxy-4'-dimethylaminobenzophenone. The sensitizer may contain N,N,N',N'-tetraalkyl-4,4'-diaminobenzophenone from the viewpoint of easily obtaining good resolution and adhesion.

[0072] Examples of anthracene compounds 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.

[0073] Examples of 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 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]quinoridine-11-one. The sensitizer may contain 2,3,6,7-tetrahydro-9-methyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinoridine-11-one from the viewpoint of easily obtaining good sensitivity.

[0074] The content of 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 per 100 parts by mass of the total amount of components (A) and (B).

[0075] The photosensitive resin composition according to this embodiment may further contain, as needed, additives such as dyes, photochromicants, thermal color inhibitors, plasticizers, pigments, fillers, defoamers, flame retardants, adhesion promoters, leveling agents, release accelerators, antioxidants, fragrances, imaging agents, thermal crosslinking agents, and polymerization inhibitors. These additives can be used individually or in combination of two or more.

[0076] Examples of dyes include malachite green, Victoria pure blue, brilliant green, and methyl violet. Examples of photochromic agents include tribromophenylsulfone, leucocrystal violet, diphenylamine, benzylamine, triphenylamine, diethylaniline, and o-chloroaniline. Examples of plasticizers include p-toluenesulfonamide.

[0077] The photosensitive resin composition can be dissolved in solvents such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, or a mixture thereof, as needed, to prepare a solution with a solid content of approximately 30-60% by mass.

[0078] 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.

[0079] The photosensitive element according to this embodiment may be provided with a protective film (not shown) on the side of the photosensitive layer 20 opposite to the support film 10 (the second surface 10b side). It is preferable to use a protective film such that the adhesive force between the photosensitive layer 20 and the protective film is less than the adhesive force between the photosensitive layer 20 and the support film 10. Polyolefin films such as polyethylene and polypropylene can be used as the protective film. The protective film may also be a polyethylene film.

[0080] The thickness of the protective film may be 5-100 μm, 5-70 μm, 10-60 μm, 10-50 μm, 15-40 μm, or 15-30 μm.

[0081] The photosensitive element of this embodiment may include an intermediate layer (not shown) between the support film and the photosensitive layer. The adhesive force between the support film and the intermediate layer may be less than the adhesive force 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 an intermediate layer forming resin composition, which will be described later.

[0082] The resin composition for forming the intermediate layer may also contain a water-soluble resin. Including a water-soluble resin tends to improve the solubility of the formed intermediate layer. It also tends to improve stability by making it easier to maintain layer separation between the formed intermediate layer and the photosensitive layer for a long period of time. Examples of water-soluble resins include polyvinyl alcohol and polyvinylpyrrolidone. From the viewpoint of having a low oxygen permeability coefficient and being able to further suppress the deactivation of radicals generated by the active light used for exposure, the resin composition for forming the intermediate layer may also contain polyvinyl alcohol. Polyvinyl alcohol can be obtained, for example, by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. The degree of saponification 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 degree of saponification 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, "degree of saponification" refers to the value measured in accordance with JIS K 6726 (1994) (Test method for polyvinyl alcohol) as defined by the Japanese Industrial Standards. The upper limit of the degree of saponification may be 100 mol%.

[0083] The average degree of polymerization of polyvinyl alcohol may be 300-3500, 300-2500, or 300-1000. The average degree of polymerization of polyvinylpyrrolidone may be 10000-100000 or 10000-50000. The above polyvinyl alcohol may be a combination of two or more types of polyvinyl alcohol with different degrees of saponification, viscosity, degree of polymerization, and modified species.

[0084] The resin composition for forming the intermediate layer may contain a resin that is soluble in the developer. The resin that is soluble in the developer may, for example, contain component (A) used in photosensitive resin compositions, or component (B). Including a resin that is soluble in the developer tends to improve the adhesion between the formed intermediate layer and the photosensitive layer, and also tends to facilitate the formation of the photosensitive layer on the formed intermediate layer.

[0085] The resin composition for forming the intermediate layer may optionally contain at least one solvent to improve the handling properties of the resin composition and to adjust its viscosity and storage stability. Examples of solvents include water and organic solvents. Examples of organic solvents include methanol, acetone, toluene, or mixtures thereof. Methanol may also be included from the viewpoint of improving the drying efficiency when forming the intermediate layer. Furthermore, if the resin composition for forming the intermediate layer contains a water-soluble resin, water, and methanol, the methanol content 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 water-soluble resin content 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.

[0086] The resin composition for forming the intermediate layer may contain 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 included, the amount 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 per 100 parts by mass of the resin composition for forming the intermediate layer, from the viewpoint of ease of intermediate layer formation.

[0087] As surfactants, silicone-based surfactants or fluorine-based surfactants may be included from the viewpoint of improving peelability with the support film. These surfactants can be used individually or in combination of two or more. When surfactants are included, the amount of 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 per 100 parts by mass of the resin composition for forming the intermediate layer, from the viewpoint of ease of intermediate layer formation.

[0088] As plasticizers, for example, polyhydric alcohol compounds may be included to improve the ease of forming the intermediate layer. Examples of plasticizers include glycerols 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 can be used individually or in combination of two or more.

[0089] The thickness of the intermediate layer is not particularly limited, but from the viewpoint of developability, it may be 12 μm or less, 10 μm or less, or 8 μm or less. Furthermore, from the viewpoint of ease of intermediate layer formation and resolution, the thickness of the intermediate layer may be 1.0 μm or more, 1.5 μm or more, or 2.0 μm or more.

[0090] [Method for forming a resist pattern] The resist pattern formation method according to this embodiment comprises a lamination step of laminating the photosensitive layer 20 of the photosensitive element 1 onto a substrate in the order of photosensitive layer and support film; an exposure step of irradiating a predetermined portion of the photosensitive layer 20 with active light through the support film 10 to form a photocurable portion; and a development step of removing the region of the photosensitive layer 20 other than the photocurable portion.

[0091] In the lamination process, for example, the photosensitive layer and support film of the photosensitive element are laminated on the substrate in this order. In the lamination process, one method for laminating the photosensitive layer 20 on the substrate is, for example, if a protective film is present on the photosensitive layer 20, to remove the protective film and then laminate the photosensitive layer 20 by heating it to about 70 to 130°C and pressing it onto the substrate under a pressure of about 0.1 to 1 MPa. It is also possible to laminate under reduced pressure in the lamination process. The surface on the substrate on which the photosensitive layer 20 is laminated is usually a metal surface, but is not particularly limited. Furthermore, preheating treatment of the substrate may be performed to further improve lamination properties.

[0092] Next, in the exposure process, for example, an active light is irradiated onto a predetermined portion of the photosensitive layer 20 through the support film 10 to form a photocured portion on the photosensitive layer 20. Examples of exposure methods include irradiating an active light in an image pattern via a negative or positive mask pattern called artwork (mask exposure method), irradiating an active light in an image pattern using projection exposure, and irradiating an active light in an image pattern using direct drawing exposure methods such as LDI (Laser Direct Imaging) exposure and DLP (Digital Light Processing) exposure.

[0093] As the light source for the active ray, known light sources can be used, such as carbon arc lamps, mercury vapor arc lamps, high-pressure mercury lamps, xenon lamps, gas lasers such as argon lasers, solid-state lasers such as YAG lasers, and semiconductor lasers that effectively emit ultraviolet and visible light.

[0094] From the viewpoint of improving adhesion, post-exposure baking (PEB) may be performed after exposure but before development. The temperature for PEB may be 50-100°C. A hot plate, box dryer, heated roll, etc. may be used as the heating device.

[0095] In the development process, 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.

[0096] In the development process, after peeling the support film 10 off from the photosensitive layer 20, the areas of the photosensitive layer other than the photocured areas are removed. In the development process, the unexposed areas (unphotocured areas) of the photosensitive layer 20 are removed by wet development or dry development using a developer such as an alkaline aqueous solution, an aqueous developer, or an organic solvent, and a resist pattern can be manufactured.

[0097] Examples of alkaline aqueous solutions include 0.1-5% by mass sodium carbonate solution, 0.1-5% by mass potassium carbonate solution, and 0.1-5% by mass sodium hydroxide solution. The pH of the alkaline aqueous solution is preferably in the range of 9-11. 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 surfactants, defoamers, organic solvents, etc. Examples of developing methods include the dipping method, the spraying method, brushing, and scrubbing.

[0098] As a post-development treatment, heating at approximately 60-250°C or applying 0.2-10 J / cm² may be performed as needed. 2 The resist pattern may be further hardened by exposure to a certain extent.

[0099] [Manufacturing method for printed circuit boards] The method for manufacturing a printed circuit board according to this embodiment includes a step of forming a conductor pattern by etching or plating a substrate having a resist pattern formed by the resist pattern formation method described above. Here, the etching or plating of the substrate can be performed by etching or plating the surface of the substrate using a known method, with the resist pattern used as a mask.

[0100] Examples of etching solutions used for etching include cupric chloride solution, ferric chloride solution, and alkaline etching solution. Examples of plating include copper plating, solder plating, nickel plating, and gold plating.

[0101] After etching or plating, the resist pattern can be removed using, for example, an aqueous solution that is more strongly alkaline than the alkaline aqueous solution used for development. Examples of such strongly alkaline aqueous solutions include 1-10% by mass sodium hydroxide aqueous solution and 1-10% by mass potassium hydroxide aqueous solution. Examples of removal methods include immersion and spraying. The printed circuit board on which the resist pattern is formed may be a multilayer printed circuit board and may have small-diameter through-holes.

[0102] When plating is performed on a substrate comprising an insulating layer and a conductive layer formed on the insulating layer, it is necessary to remove the conductive layer other than the resist pattern. Examples of removal methods include light etching after peeling off the resist pattern; or masking the wiring portion with solder by peeling off the resist pattern after solder plating or the like following the above plating, and then treating only the conductive layer in the areas not masked by solder with an etching solution. [Examples]

[0103] The contents of this disclosure will be described in more detail below using examples and comparative examples, but the present invention is not limited to these examples.

[0104] [Photosensitive resin composition] A photosensitive resin composition was 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.

[0105] (Binder polymer) A-1: Ethylene glycol monomethyl ether / toluene solution (solids content: 40% by mass) of a copolymer of methacrylic acid / styrene / benzyl methacrylate / 2-hydroxyethyl methacrylate (mass ratio: 27 / 50 / 20 / 3, Mw: 35000, acid value: 176 mgKOH / g)

[0106] The Mw of the binder polymer was measured by gel permeation chromatography (GPC) under the following conditions and calculated by conversion using a calibration curve for standard polystyrene. Pump: L-2130 model (manufactured by Hitachi High-Technologies Corporation) Detector: L-2490 type RI (manufactured by Hitachi High-Technologies Corporation) Column oven: L-2350 (manufactured by Hitachi High-Technologies Corporation) Columns: Gelpack GL-R440 + Gelpack GL-R450 + Gelpack GL-R400M (3 columns total) (Manufactured by Resonaq Corporation) Column size: 10.7mm I.D × 300mm Eluent: Tetrahydrofuran Sample concentration: 10 mg / 2 mL Injection volume: 200μL Flow rate: 2.05mL / min Measurement temperature: 25℃

[0107] The acid value of the binder polymer was measured using the following procedure. First, the binder polymer was weighed into an Erlenmeyer flask. Next, a mixed solvent (mass ratio: toluene / methanol = 70 / 30) was added to dissolve the binder polymer, and then phenolphthalein solution was added as an indicator. The acid value was then obtained by titration with a 0.1 mol / L (N / 10) potassium hydroxide solution (alcohol solution).

[0108] (Photopolymerizable compound) FA-321M: EO-modified bisphenol A dimethacrylate (manufactured by Resonaq Corporation, number of EO groups: 10 (average value)) FA-024M: Polyalkylene glycol dimethacrylate (manufactured by Resonac Corporation, number of EO groups: 12 (average), number of PO groups: 4 (average)) 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 Industrial 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 Co., Ltd.) (Coloring agent) LCV: Leucocrystal violet (manufactured by Yamada Chemical Industries Co., Ltd.)

[0109] [Table 1]

[0110] [Support film] As support films for the photosensitive elements, biaxially oriented PET films (16 μm thick) S1 to S12 were prepared. Using a confocal microscope (Lasertec Corporation, product name "Hybrid Laser Microscope OPTELICS HYBRID"), the first and second surfaces of the support film were measured at 0.0225 mm. 2 The number of lubricants contained in a (0.150 mm × 0.150 mm) area was measured. Images were acquired under the conditions shown in Table 2 below, with a lens numerical aperture (Na) of 0.8, a magnification of 50x, and a digital zoom of 2x. The size and number of lubricants were calculated from the pixels in the images. The results for S1 to S7 are shown in Table 3, and the results for S8 to S12 are shown in Table 4. Note that S1 to S12 contained lubricants with a particle size of 2.0 μm or less.

[0111] [Table 2]

[0112] [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, it was dried in a 100°C hot air convection dryer for 2 minutes to form a 15 μm thick photosensitive layer. Then, a PE film (manufactured by Tamapoly Co., Ltd., product name "NF-15A", thickness: 28 μm) was laminated onto the photosensitive layer as a protective film to create a photosensitive element.

[0113] [evaluation] (Fabrication of laminates) A substrate a was prepared by sputtering titanium at 10 nm and then copper at 100 nm onto a PET film (manufactured by Toyobo Co., Ltd., product name "Cosmoshine A4160", thickness: 125 μm). After heating 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 as described above. This resulted in a laminate having substrate a, photosensitive layer, and support film in this order in the lamination 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.

[0114] (Formation of resist pattern) Using a phototool with a 41-step tablet, a glass-chromium type phototool with a wiring pattern of 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 with a high-pressure mercury lamp (manufactured by Ushio Inc., product name "UX-2240"), the photosensitive layer of the laminate was exposed at an irradiation energy level that resulted in 11 remaining step stages after development of the 41-step tablet. Next, the support film was peeled off, and the unexposed areas were removed by spray development with a 1% by mass sodium carbonate aqueous solution at 30°C to form a resist pattern with line width / space width of 5.0 / 5.0 (unit: μm).

[0115] A 73 μm × 55 μm area of ​​a substrate with a resist pattern formed on it was imaged using the NEXIV VMZ-R4540 (manufactured by Nikon Corporation, product name). Scanning measurements with the NEXIV VMZ-R4540 were used to identify the contour of the formed resist pattern, and the coordinates of the resist pattern contour were measured for six lines of the resist pattern. For the coordinate measurement, 260 coordinate points were measured at 0.2 μm intervals over a length of 52 μm, for both the contour on one side and the contour on the other side of each line. These measurements were performed at three locations for each of the six lines. This resulted in a total of 9360 coordinate points being measured. Based on these 9360 measured coordinate points, the variation (3σ) of the resist pattern contour was calculated. The 3σ of the contour is also called LER (Line Edge Roughness). A smaller value indicates a finer resist pattern.

[0116] [Table 3]

[0117] [Table 4] [Explanation of symbols]

[0118] 1...Photosensitive element, 10...Support film, 10a...First surface, 10b...Second surface, 20...Photosensitive layer.

Claims

1. The device comprises a support film containing a lubricant and a photosensitive layer formed on a first surface of the support film, The number of lubricants with a particle size of 0.8 μm or larger contained in the second surface of the support film opposite to the first surface is 0.0225 mm ２ Each value is between 1 and 80. A photosensitive element wherein the number of lubricants with a particle size of 0.8 μm or larger contained in the first surface is 10 to 400 per 0.0225 mm², and the total number of lubricants contained in the first surface is 155 to 1400 per 0.0225 mm².

2. The total number of lubricants contained in the second surface is 0.0225 mm ２ The photosensitive element according to claim 1, wherein the value per square meter is 2000 or less.

3. The photosensitive element according to claim 1, wherein the value obtained by dividing the number of lubricants with a particle size of 0.8 μm or more contained in the second surface by the total number of lubricants contained in the second surface is 0.20 or less.

4. The number of lubricants with a particle size of 0.8 μm or larger contained in the first surface is 0.0225 mm ２ The photosensitive element according to claim 1, wherein the number of elements per unit area is 10 or more and 200 or less.

5. The photosensitive element according to claim 1, wherein the average particle size of the lubricant contained in the first surface and the second surface is 0.3 μm or more and 1.0 μm or less.

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

7. The photosensitive element according to claim 1, wherein the support film does not contain lubricants with a particle size greater than 3.0 μm.

8. A lamination step of stacking the photosensitive element according to any one of claims 1 to 7 on a substrate in the order of photosensitive layer, support film, An exposure step in which an active light beam is irradiated onto a predetermined portion of the photosensitive layer through the support film to form a photocured portion, A developing step to remove the region of the photosensitive layer other than the photocured portion, A method for forming a resist pattern, including [a specific component].

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

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