JP2011018069A - Photosensitive element, method for forming resist pattern using the same, and method for manufacturing printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive element exhibiting sufficient sensitivity and resolution when light at a wavelength of 400-450 nm is used as exposure light, and giving good resist features.SOLUTION: The photosensitive element includes a support film X and a photosensitive resin composition layer Z. The photosensitive resin composition as the material of Z contains a binder polymer A, a photopolymerizable compound B having an ethylenically unsaturated bond, and a photoinitiator C. The photoinitiator C contains 4,4'-bis(dialkylamino)benzophenone and/or 4,4'-bis(alkylamino)benzophenone. The layer thickness Q [μm] of Z, the total mass Wa [g] of A in Z, the total mass Wb [g] of B in Z and the mass Wc [g] of benzophenone in Z satisfy all of the conditions represented by expressions (1): P={Wc/(Wa+Wb)}×100, (2): P×Q=R and (3): 6.5≤R≤21.5.

Description

  The present invention relates to a photosensitive element, a resist pattern forming method using the same, and a printed wiring board manufacturing method.

  In the field of manufacturing printed wiring boards, as a resist material used for etching and plating, a photosensitive resin composition and a layer made of this photosensitive resin composition (hereinafter referred to as “photosensitive resin composition layer”) are used. Photosensitive elements (laminates) formed on a support film and having a structure in which a protective film is disposed on a photosensitive resin composition layer are widely used.

  Conventionally, a printed wiring board is manufactured, for example, by the following procedure using the photosensitive element. That is, first, the photosensitive resin composition layer of the photosensitive element is laminated on a circuit forming substrate such as a copper-clad laminate. At this time, the surface opposite to the surface of the photosensitive resin composition layer in contact with the support film (hereinafter referred to as the “lower surface” of the photosensitive resin composition layer) (hereinafter referred to as the “upper surface of the photosensitive resin composition layer”). ") In close contact with the surface of the circuit forming substrate on which the circuit is to be formed. Therefore, when the protective film is arrange | positioned on the upper surface of the photosensitive resin composition layer, this lamination operation is performed while peeling off the protective film. Next, the photosensitive resin composition layer is thermocompression bonded to the underlying circuit forming substrate (normal pressure laminating method).

  Next, pattern exposure is performed through a mask film or the like. At this time, the support film is peeled off at any timing before or after exposure. Thereafter, the unexposed portion is dissolved or dispersed and removed with a developer. Next, an etching process or a plating process is performed to form a pattern, and finally the cured portion is peeled and removed.

  Here, the etching treatment is a method of removing a resist after etching away a metal surface not covered with a cured resist formed after development. On the other hand, the plating process is a method in which a metal surface not covered with a hardened resist formed after development is subjected to a plating process such as copper and solder and then the resist is removed and the metal surface covered with the resist is etched. .

  Conventionally, a mercury lamp has been mainly used as the light source for the above-described pattern exposure. However, the light from the mercury lamp contains ultraviolet rays (light having a wavelength of 400 nm or less) harmful to the human body, which has a problem in work safety. Although there is an exposure method using a visible light laser as a light source, this method requires a resist sensitive to visible light, and this resist has to be handled in a dark room or under a red lamp.

  In consideration of the above points, a technique has been proposed in which actinic rays obtained by cutting 99.5% or more of light having a wavelength of 365 nm or less using a filter among light emitted from a mercury lamp light source are used for pattern exposure.

  In recent years, a long-lived and high-power gallium nitride blue laser light source that oscillates light having a wavelength of 405 nm has become available at low cost, and a technique for using this also as a light source for pattern exposure has been proposed.

  In recent years, a direct drawing method called a digital light processing (DLP (Digital Light Processing)) exposure method has been proposed (for example, see Non-Patent Document 1). Even in this exposure method, there are cases where an actinic ray obtained by cutting 99.5% or more of light having a wavelength of 365 nm or less out of light emitted from a mercury lamp light source using a filter or a blue laser light source is used.

Electronics Packaging Technology June 2002 (p.74-79)

  However, since the conventional photosensitive element is designed to exhibit optimum photosensitive characteristics with respect to the full wavelength exposure of a mercury lamp light source centered on light having a wavelength of 365 nm, light having a wavelength of 400 to 450 nm (mercury lamp light source) Actinic rays obtained by cutting 99.5% or more of light having a wavelength of 365 nm or less using light from the light emitted from the light, and exposure light by light having a wavelength of 405 nm of a semiconductor laser including those described in Non-Patent Document 1. ) Is intended to perform pattern exposure, the sensitivity of the photosensitive element with respect to the light having a wavelength of 400 to 450 nm is low, so that the throughput is low, and sufficient resolution and a good resist shape can be obtained. could not.

  The present invention has been made in view of the above problems, and when using light having a wavelength of 400 to 450 nm as exposure light, sufficient sensitivity and resolution can be obtained, and still a good resist shape can be obtained. It is an object to provide a photosensitive element that can be used. Another object of the present invention is to provide a method for forming a resist pattern using such a photosensitive element. Furthermore, the present invention uses such a photosensitive element, and a printed wiring board manufacturing method capable of manufacturing a high-density printed wiring board with high throughput when light having a wavelength of 400 to 450 nm is used as exposure light. The purpose is to provide.

  The inventors of the present invention have one of the main reasons why the above-described conventional photosensitive element has a low sensitivity to light having a wavelength of 400 to 450 nm. The optical density (hereinafter referred to as “O”) of the photosensitive element with respect to the above wavelength region. .D. Value ") is small, the light in the above wavelength region cannot be sufficiently absorbed, and the photopolymerization of the component (B) (photopolymerizable compound) in the photosensitive element cannot be started. I found out.

  The inventors further studied and added the compound having a large light absorption characteristic with respect to light having a wavelength of 400 to 450 nm as a photopolymerization initiator component in the photosensitive resin composition layer. It was found that there is a concern that the storage stability under yellow light (light having a wavelength of 580 to 600 nm) may be lowered although the sensitivity is high.

  Furthermore, the present inventors have storage stability under yellow light in order to improve the sensitivity to light having a wavelength of 400 to 450 nm while sufficiently ensuring storage stability under yellow light. In addition, a compound having an appropriate light absorption characteristic for light having a wavelength of 400 to 450 nm may be added in a larger amount than that contained in the photosensitive resin composition layer of the conventional photosensitive element. I found it effective.

  And as a result of intensive studies, the present inventors have achieved the above object by configuring a photosensitive element using a photosensitive resin composition layer containing a specific amount of a specific photopolymerization initiator component. We have found that this is possible and have reached the present invention.

That is, the present invention is a photosensitive element having a support film and a photosensitive resin composition layer disposed on the support film,
The photosensitive resin composition layer contains a photosensitive resin composition,
The photosensitive resin composition includes (A) a binder polymer, (B) a photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond, and (C) a photopolymerization initiator,
The (C) photopolymerization initiator contains at least 4,4′-bis (dialkylamino) benzophenone and / or 4,4′-bis (alkylamino) benzophenone as a constituent component,
The layer thickness Q [μm] of the photosensitive resin composition layer, the total mass Wa [g] of the (A) binder polymer in the photosensitive resin composition layer, and the above in the photosensitive resin composition layer (B) The total mass Wb [g] of the photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond, and the 4,4′-bis (dialkylamino) benzophenone in the photosensitive resin composition layer And / or the mass Wc [g] of 4,4′-bis (alkylamino) benzophenone is adjusted so as to simultaneously satisfy the conditions represented by the following formulas (1) to (3),
It is characterized by.
P = {Wc / (Wa + Wb)} × 100 (1)
P × Q = R (2)
6.5 ≦ R ≦ 21.5 (3)

  The photosensitive resin composition used as the constituent material of the photosensitive resin composition layer of the photosensitive element of the present invention comprises (C) 4,4′-bis (dialkylamino) benzophenone and / or as a constituent of the photopolymerization initiator. Contains 4,4'-bis (alkylamino) benzophenone. The benzophenone has a relatively large light absorption characteristic with respect to light having a wavelength of 400 to 450 nm, and has good storage stability under yellow light. And by adjusting this content rate so that the conditions of the above-mentioned formulas (1) to (3) are simultaneously satisfied, sufficient sensitivity and resolution can be obtained when light having a wavelength of 400 to 450 nm is used as exposure light. However, a good resist shape can be obtained.

  When the layer thickness of the photosensitive resin composition layer is constant, if the blended amount of the benzophenone is excessively increased to increase the sensitivity to light with a wavelength of 400 to 450 nm (when R exceeds 21.5), Of the functional resin composition layer. D. Although the value increases and the sensitivity to light with a wavelength of 400 to 450 nm increases, the light does not easily reach the bottom of the photosensitive element, so the curability of the bottom becomes insufficient, and the resist shape after development is inverted trapezoidal. Or the resolution is insufficient.

  On the other hand, when the layer thickness of the photosensitive resin composition layer is constant, if the blending amount of the benzophenone is too small (when R is less than 6.5), sufficient sensitivity to light with a wavelength of 400 to 450 nm is obtained. It becomes impossible.

  Furthermore, the sensitivity of the photosensitive resin composition layer to light having a wavelength of 400 to 450 nm and the storage stability under yellow light depend not only on the amount of the benzophenone but also on the layer thickness of the photosensitive resin composition layer. Taking this into consideration, the present inventors have found the conditions of the above-mentioned formulas (1) to (3).

  In the present invention, the 4,4′-bis (dialkylamino) benzophenone is 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (dimethylamino) benzophenone, or 4,4′-. Bis (methylethylamino) benzophenone is preferred. These benzophenone compounds have storage stability under yellow light and have appropriate light absorption characteristics for light having a wavelength of 400 to 450 nm.

In the present invention, R preferably satisfies the condition represented by the following formula (4), and more preferably satisfies the condition represented by the following formula (5).
7.2 ≦ R ≦ 20.0 (4)
9.6 ≦ R ≦ 18.5 (5)

  The photosensitive element may be (i) a photosensitive element exposed by light having a wavelength of 400 to 450 nm, or (ii) a photosensitive element exposed by light having a wavelength of 400 to 415 nm. Further, the photosensitive element is (iii) a photosensitive element exposed by light emitted from a blue laser or (iv) a plurality of mirrors are arranged, and the angle of each mirror is changed as necessary, It is further preferable that the photosensitive element is exposed by a direct drawing method (more preferably, a digital light processing exposure method) in which the exposure light becomes an image. Furthermore, it is further preferable that the photosensitive element has a property that the photosensitive resin composition contained in the photosensitive resin composition layer is exposed and polymerized as described above. In a more preferred embodiment, the light having a wavelength of 400 to 415 nm is laser light (preferably light emitted from a semiconductor laser diode, more preferably light emitted from a gallium nitride semiconductor laser), and emitted from the blue laser. The emitted light is light having a wavelength of 400 to 415 nm emitted from a gallium nitride blue laser, and the exposure by the direct drawing method is performed with light having a wavelength of 400 to 415 nm.

  The photosensitive element may be (v) a photosensitive element that is exposed to an actinic ray obtained by cutting 90% or more of light having a wavelength of 365 nm or less. Furthermore, it is further preferable that the photosensitive element has a property that the photosensitive resin composition contained in the photosensitive resin composition layer is exposed and polymerized as described above. In this case, the light having a wavelength of 365 nm or less is more preferably 99.0% cut, and particularly preferably 99.5% or more cut.

  The photosensitive element is also (vi) a photosensitive element that is exposed to light having an area integrated intensity a having a wavelength of 400 nm to 450 nm in an oscillation spectrum of a light source that is 10 times or more of an area integrated intensity b having a wavelength of 300 nm to less than 400 nm. It is good to be.

  By adopting the above preferred embodiment of the photosensitive element, sensitivity and resolution can be further improved, and a good resist shape can be surely obtained.

In the present invention, the circuit of the circuit forming substrate should be formed on the surface of the photosensitive resin composition layer of the present invention that is opposite to the surface in contact with the support film in the photosensitive resin composition layer. A first step of laminating the photosensitive resin composition layer on the circuit-forming substrate by being adhered to a surface;
A second step of irradiating a predetermined portion to be exposed of the photosensitive resin composition layer with an actinic ray to form an exposed portion;
Next, a third step of removing an unexposed part other than the exposed part,
Including at least,
A method for forming a resist pattern is provided.

  Moreover, this invention provides the manufacturing method of the printed wiring board characterized by etching or plating the board | substrate for circuit formation in which the resist pattern was formed by the formation method of the resist pattern of this invention mentioned above.

  Since the resist pattern forming method of the present invention and the printed wiring board manufacturing method of the present invention use the above-described photosensitive element of the present invention, light having a wavelength of 400 to 450 nm is used as exposure light for the photosensitive element. Even in this case, sufficient sensitivity and resolution can be obtained, and a resist pattern capable of obtaining a good resist shape can be obtained, and a dense printed wiring board can be manufactured with high throughput. be able to.

Further, the present invention is a photosensitive element having a support film, a protective film made of a synthetic resin, and a photosensitive resin composition layer disposed between the support film and the protective film,
The photosensitive resin composition layer contains a photosensitive resin composition,
The photosensitive resin composition includes (A) a binder polymer, (B) a photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond, and (C) a photopolymerization initiator,
(C) The photopolymerization initiator contains at least 4,4′-bis (dialkylamino) benzophenone and / or 4,4′-bis (alkylamino) benzophenone as a constituent component,
Layer thickness Q [μm] of the photosensitive resin composition layer, (A) total mass Wa [g] of the binder polymer in the photosensitive resin composition layer, and (B) at least 1 in the photosensitive resin composition layer The total mass Wb [g] of the photopolymerizable compound having two polymerizable ethylenically unsaturated bonds, and 4,4′-bis (dialkylamino) benzophenone and / or 4,4 ′ in the photosensitive resin composition layer. -The mass Wc [g] of bis (alkylamino) benzophenone is adjusted so as to satisfy the conditions represented by the following formulas (1) to (3) at the same time.
A photosensitive element is provided.
P = {Wc / (Wa + Wb)} × 100 (1)
P × Q = R (2)
6.5 ≦ R ≦ 21.5 (3)

Furthermore, the present invention is a method in which the protective film of the photosensitive element of the present invention described above is gradually peeled off from the photosensitive resin composition layer, and at the same time, the surface portion of the photosensitive resin composition layer that is gradually exposed is removed. A first step of laminating a photosensitive resin composition layer on the circuit forming substrate by bringing the circuit forming substrate into close contact with the surface on which the circuit is to be formed;
A second step of irradiating a predetermined portion to be exposed of the photosensitive resin composition layer with an actinic ray to form an exposed portion;
Next, a third step of removing an unexposed part other than the exposed part,
Including at least,
A method for forming a resist pattern is provided.

  Moreover, this invention provides the manufacturing method of the printed wiring board characterized by etching or plating the board | substrate for circuit formation in which the resist pattern was formed by the formation method of the resist pattern of this invention mentioned above.

  According to the present invention, it is possible to provide a photosensitive element capable of obtaining sufficient sensitivity and resolution when a light having a wavelength of 400 to 450 nm is used as exposure light and still obtaining a good resist shape. It becomes possible.

  Moreover, according to this invention, it becomes possible to provide the formation method of a resist pattern using this photosensitive element, and the manufacturing method of a printed wiring board. More specifically, it is possible to provide a resist pattern forming method capable of obtaining sufficient sensitivity and resolution when using light having a wavelength of 400 to 450 nm as exposure light and still obtaining a good resist shape. It becomes possible. Furthermore, it is possible to provide a method for manufacturing a printed wiring board capable of manufacturing a high-density printed wiring board with high throughput when light having a wavelength of 400 to 450 nm is used as exposure light.

It is a schematic cross section which shows suitable one Embodiment of the photosensitive element of this invention. It is a schematic cross section which shows other suitable embodiment of the photosensitive element of this invention. It is an oscillation spectrum figure of a mercury lamp light source. It is an oscillation spectrum figure of the mercury lamp light source which uses a filter.

  Hereinafter, embodiments of the present invention will be described in detail. In the present invention, (meth) acrylic acid means acrylic acid or methacrylic acid, (meth) acrylate means acrylate or a corresponding methacrylate, and (meth) acryloyl group means acryloyl group or methacryloyl group. means.

(Photosensitive resin composition)
First, the photosensitive resin composition used as the constituent material of the photosensitive resin composition layer of the photosensitive element of this invention is demonstrated. This photosensitive resin composition is a photosensitive resin composition that is a constituent material of a photosensitive resin composition layer of a photosensitive element having at least a support film and a photosensitive resin composition layer disposed on the support film. And (B) containing at least a binder polymer, (B) a photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond, and (C) a photopolymerization initiator.

  First, the binder polymer as component (A) will be described.

  From the viewpoint of improving both the adhesion and release properties of the photosensitive resin composition layer comprising the photosensitive resin composition as a constituent material to the circuit-forming substrate, this (A) binder polymer has styrene or styrene in its molecule. It preferably contains at least repeating units based on derivatives. Furthermore, the content of the repeating unit based on styrene or a styrene derivative is preferably 3 to 30% by mass, more preferably 4 to 28% by mass based on the total mass of the molecule, and 5 to 27% by mass. It is particularly preferred. If this content is less than 3% by mass, the above-mentioned adhesion tends to be inferior. If this content exceeds 30% by mass, the peel piece tends to be large and the peel time tends to be long. In addition, from the viewpoints of adhesion and release characteristics, the (A) binder polymer preferably includes a repeating unit based on methacrylic acid as a constituent component.

  In the present invention, the “styrene derivative” refers to a compound in which a hydrogen atom in styrene is substituted with a substituent (an organic group such as an alkyl group or a halogen atom).

  When forming the photosensitive resin composition layer using this binder polymer, one type of binder polymer may be used alone, or two or more types of binder polymers may be used in any combination. As a binder polymer in the case of using two or more types in combination, for example, two or more types of binder polymers comprising different copolymerization components (including different repeating units as constituent components), two or more types of binders having different weight average molecular weights Examples thereof include polymers and two or more types of binder polymers having different degrees of dispersion. In addition, a polymer having a multimode molecular weight distribution described in JP-A No. 11-327137 can also be used.

  The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the binder polymer can be measured by gel permeation chromatography (GPC) (converted by a calibration curve using standard polystyrene).

  According to this measurement method, the Mw of the binder polymer is preferably 5000 to 300000, and more preferably 40000 to 150,000. When Mw is less than 5000, the developer resistance tends to decrease, and when it exceeds 300,000, the development time tends to be long.

  The (A) binder polymer preferably has a dispersity (Mw / Mn) of 1.0 to 3.0, and more preferably 1.0 to 2.0. When the degree of dispersion exceeds 3.0, the adhesion and resolution tend to decrease.

  Examples of the binder polymer (A) include acrylic resins, styrene resins, epoxy resins, amide resins, amide epoxy resins, alkyd resins, and phenol resins. From the viewpoint of alkali developability, an acrylic resin is preferable. These can be used alone or in combination of two or more.

  The (A) binder polymer can be produced, for example, by radical polymerization of a polymerizable monomer. Examples of the polymerizable monomer include polymerizable styrene derivatives substituted at the α-position or aromatic ring such as styrene, vinyltoluene, α-methylstyrene and the like as an essential copolymerization component. Other components include acrylamide such as diacetone acrylamide, esters of vinyl alcohol such as acrylonitrile and vinyl-n-butyl ether, alkyl (meth) acrylate, tetrahydrofurfuryl ester (meth) acrylate, dimethyl (meth) acrylate Aminoethyl ester, (meth) acrylic acid diethylaminoethyl ester, (meth) acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate , (Meth) acrylic acid, α-bromo (meth) acrylic acid, α-chloro (meth) acrylic acid, β-furyl (meth) acrylic acid, β-styryl (meth) acrylic acid, maleic acid, maleic anhydride , Monomethyl maleate, Ynoic acid monoethyl maleate monoesters such as maleic acid monoisopropyl, fumaric acid, cinnamic acid, alpha-cyanocinnamic acid, itaconic acid, crotonic acid, propiolic acid. These may be used alone or in any combination of two or more.

As said (meth) acrylic-acid alkylester, the compound etc. which the hydroxyl group, the epoxy group, the halogen group, etc. substituted the compound represented by the following general formula (I), the alkyl group of these compounds, etc. are mentioned, for example. However, in the following general formula (I), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 12 carbon atoms.

^{_{CH 2 = C (R 3)}} -COOR 4 ··· (I)

Examples of the alkyl group having 1 to 12 carbon atoms represented by R ⁴ in the general formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, Nonyl group, decyl group, undecyl group, dodecyl group and structural isomers thereof can be mentioned. Examples of the monomer represented by the general formula (I) 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, (meth) acrylic acid dodecyl ester, and the like. These may be used alone or in any combination of two or more.

  The (A) binder polymer in the present invention is preferably composed of one or more kinds of polymers having a carboxyl group from the viewpoint of developability when alkali development is performed using an alkaline solution. Such a (A) binder polymer can be produced, for example, by radical polymerization of a polymerizable monomer having a carboxyl group and another polymerizable monomer.

  (A) It is preferable that the acid value of a binder polymer is 30-200 mgKOH / g, and it is more preferable that it is 45-150 mgKOH / g. When the acid value is less than 30 mg KOH / g, the development time tends to be long, and when it exceeds 200 mg KOH / g, the developer resistance of the photocured resist tends to be lowered. Moreover, when performing solvent image development as a image development process, it is preferable to prepare the polymerizable monomer which has a carboxyl group in a small quantity.

  Moreover, (A) binder polymer may have a characteristic group having photosensitivity to light having a wavelength of 400 to 450 nm in its molecule, if necessary.

  Next, the photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond (hereinafter referred to as “photopolymerizable compound”), which is the component (B), will be described.

  (B) As the photopolymerizable compound, for example, a compound obtained by reacting an α, β-unsaturated carboxylic acid with a polyhydric alcohol, a bisphenol A-based (meth) acrylate compound, a glycidyl group-containing compound with α, β- Compounds obtained by reacting unsaturated carboxylic acids, urethane monomers such as (meth) acrylate compounds having a urethane bond in the molecule, nonylphenoxypolyethyleneoxyacrylate, phthalic acid compounds, (meth) acrylic acid alkyl esters, etc. It is done. These may be used alone or in combination of two or more. From the viewpoint of plating resistance and adhesion, it is preferable to use a bisphenol A-based (meth) acrylate compound or a (meth) acrylate compound having a urethane bond in the molecule as an essential component. Also, a photopolymerizable unsaturated compound having one polymerizable ethylenically unsaturated bond in the molecule and a photopolymerizable unsaturated compound having two or more polymerizable ethylenically unsaturated bonds in the molecule. Use in combination is preferable from the viewpoint of obtaining the effect of the present invention more reliably.

  Examples of the compound obtained by reacting the polyhydric alcohol with an α, β-unsaturated carboxylic acid include, for example, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 2 propylene groups. 14 polypropylene glycol di (meth) acrylate, 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, tetramethylolmethanetri (me ) Acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like. These may be used alone or in combination of two or more. Here, “EO” represents ethylene oxide, and an EO-modified compound represents one having a block structure of an ethylene oxide group. “PO” represents propylene oxide, and a PO-modified compound has a propylene oxide group block structure.

  Examples of the bisphenol A-based (meth) acrylate compound include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolypropoxy). Phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane and the like It is done. Examples of the 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) propane, 2,2 -Bis (4-((meth) acryloxytriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetraethoxy) phenyl) propane, 2,2-bis (4-((meta ) Acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptaethoxy) phenyl) Propane, 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxynona) Toxi) phenyl) propane, 2,2-bis (4-((meth) acryloxydecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl) propane, 2 , 2-bis (4-((meth) acryloxydodecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl) propane, 2,2-bis (4- ((Meth) acryloxytetradecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxy) Hexadecaethoxy) phenyl) propane and the like.

  2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). 4- (Methacryloxypentadecaethoxy) phenyl) propane is commercially available as BPE-1300 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). The number of ethylene oxide groups in one molecule of the 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane is preferably 4-20, and more preferably 8-15. . These may be used alone or in any combination of two or more.

  Examples of the (meth) acrylate compound having a urethane bond in the molecule include, for example, a (meth) acryl monomer having an OH group at the β-position and a diisocyanate compound (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, EO, PO-modified urethane di (meth) acrylate Etc. Examples of the EO-modified urethane di (meth) acrylate include UA-11 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). Examples of the EO and PO-modified urethane di (meth) acrylate include UA-13 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). These may be used alone or in combination of two or more.

  Examples of the nonylphenoxypolyethyleneoxyacrylate include nonylphenoxytetraethyleneoxyacrylate, nonylphenoxypentaethyleneoxyacrylate, nonylphenoxyhexaethyleneoxyacrylate, nonylphenoxyheptaethyleneoxyacrylate, nonylphenoxyoctaethyleneoxyacrylate, nonylphenoxynonaethylene Examples include oxyacrylate, nonylphenoxydecaethyleneoxyacrylate, and nonylphenoxyundecaethyleneoxyacrylate. These may be used alone or in any combination of two or more.

  Examples of the phthalic acid compounds include γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β ′-(meth) acryloloxyalkyl-o-phthalate. Etc. These may be used alone or in any combination of two or more.

  Next, the photopolymerization initiator which is the component (C) will be described. (C) The photopolymerization initiator contains at least 4,4′-bis (dialkylamino) benzophenone and / or 4,4′-bis (alkylamino) benzophenone as a constituent component. Here, 4,4′-bis (dialkylamino) benzophenone is 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (dimethylamino) benzophenone, or 4,4′-bis (methylethylamino). ) Benzophenone is preferred. The (C) photopolymerization initiator further preferably contains at least 4,4′-bis (diethylamino) benzophenone as a constituent component. And the blending amount (content) of 4,4′-bis (dialkylamino) benzophenone and / or 4,4′-bis (alkylamino) benzophenone in the photosensitive resin composition layer satisfies the following conditions. It is adjusted to.

That is, the layer thickness Q [μm] of the photosensitive resin composition layer, (A) the total weight Wa [g] of the binder polymer in the photosensitive resin composition layer, and (B) in the photosensitive resin composition layer The total mass Wb [g] of the photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond, and 4,4′-bis (dialkylamino) benzophenone and / or 4,4 in the photosensitive resin composition layer The mass Wc [g] of 4′-bis (alkylamino) benzophenone is adjusted so as to simultaneously satisfy the conditions represented by the following formulas (1) to (3).
P = {Wc / (Wa + Wb)} × 100 (1)
P × Q = R (2)
6.5 ≦ R ≦ 21.5 (3)

  Here, when R is less than 6.5, O.D. D. The sensitivity is low because the value is small and light cannot be absorbed sufficiently. When R exceeds 21.5, O.D. D. Although the value is high and the sensitivity can be increased, it is difficult for light to reach the bottom of the photosensitive element, so the curability of the bottom is deteriorated, the resist shape after development becomes an inverted trapezoidal shape, or the resolution is insufficient. Become. In addition, as said R, it is preferable that it is 20.0 or less, It is more preferable that it is 18.5 or less, It is further more preferable that it is 17.5 or less, It is especially preferable that it is 16.8 or less. It is very preferable that it is 14.4 or less. Moreover, as said R, it is preferable that it is 7.2 or more, and it is more preferable that it is 9.6 or more.

Moreover, it is preferable that said R satisfy | fills the conditions represented by following formula (4), and it is more preferable to satisfy | fill the conditions represented by following formula (5).
7.2 ≦ R ≦ 20.0 (4)
9.6 ≦ R ≦ 18.5 (5)

  Examples of other (C) photopolymerization initiator components include benzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-methyl-1- [4- ( Aromatic ketones such as methylthio) phenyl] -2-morpholino-propanone-1, quinones such as alkylanthraquinones, benzoin ether compounds such as benzoin alkyl ether, benzoin compounds such as benzoin and alkylbenzoin, and benzyl derivatives such as benzyldimethyl ketal 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl)- 4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) Nyl) -4,5-diphenylimidazole dimer, 2,4,5-triarylimidazole dimer such as 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 9-phenylacridine And acridine derivatives such as 1,7-bis (9,9′-acridinyl) heptane, N-phenylglycine, N-phenylglycine derivatives, and coumarin compounds.

  Further, the substituents of the aryl groups of two 2,4,5-triarylimidazoles may be the same to give the target compound, or differently give an asymmetric compound. From the viewpoint of adhesion and sensitivity, 2,4,5-triarylimidazole dimer is more preferable. These are used alone or in combination of two or more.

  If necessary, the photosensitive resin composition may include a photopolymerizable compound (such as an oxetane compound) having at least one cationically polymerizable cyclic ether group in the molecule, a cationic polymerization initiator, a dye such as malachite green, Photochromic agents such as bromophenylsulfone and leucocrystal violet, thermochromic inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, antifoaming agents, flame retardants, stabilizers, adhesion promoters, leveling agents , Peeling accelerators, antioxidants, fragrances, imaging agents, thermal crosslinking agents, and the like can be contained in an amount of about 0.01 to 20 parts by mass with respect to 100 parts by mass of the total amount of the component (A) and the component (B). . These are used alone or in combination of two or more.

  The photosensitive resin composition of the present invention is dissolved in a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, or a mixed solvent thereof. It is good also as a solution about 30-60 mass% of solid content. This solution can be used as a coating solution for forming the photosensitive resin composition layer of the photosensitive element.

  In addition, the above coating solution may be used for forming a photosensitive resin composition layer of a photosensitive element by coating and drying on a support film described later, for example, the surface of a metal plate, for example, Apply a liquid resist on the surface of an iron-based alloy such as copper, copper-based alloy, nickel, chromium, iron, stainless steel, preferably copper, copper-based alloy, iron-based alloy, and dry, and then coat the protective film It may be used.

  Moreover, although the layer thickness Q of the photosensitive resin composition layer changes with uses of the photosensitive element, it is preferable that it is about 1-100 micrometers by the thickness after drying. In the case where the above-described liquid resist is used after being coated with a protective film, examples of the protective film include polymer films such as polyethylene and polypropylene.

(Photosensitive element)
Next, the photosensitive element of the present invention will be described. FIG. 1 is a schematic sectional view showing a preferred embodiment of the photosensitive element of the present invention. The photosensitive element 1 of the present invention has at least a support film 11 and a photosensitive resin composition layer 12 disposed on the support film 11. In addition, the photosensitive element 1 of this invention is further equipped with the protective film 13 on the surface on the opposite side to the surface which is contacting the support film 11 in the photosensitive resin composition layer 12, as shown in FIG. May be.

  For the support film 11, for example, a polymer film having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester can be used. The support film (polymer film) preferably has a thickness of 1 to 100 μm. If the thickness is less than 5 μm, the support film tends to be broken when the support film is peeled off before development, and if it exceeds 25 μm, the resolution tends to decrease. One polymer film is used as a support for the photosensitive resin composition layer, and the other is used as a protective film for the photosensitive resin composition, laminated on both sides of the photosensitive resin composition layer. Also good.

  The protective film 13 preferably has a smaller adhesive strength between the photosensitive resin composition layer and the protective film than the adhesive strength between the photosensitive resin composition layer and the support, and is preferably a low fisheye film. “Fish eye” means that when a material is melted by heat, kneaded, extruded, biaxially stretched, casting method, etc., foreign materials, undissolved materials, oxidized degradation products, etc. It is taken in.

  As the protective film, for example, a polymer film having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester can be used. Examples of commercially available products include polypropylene films such as Alfan MA-410 and E-200C manufactured by Oji Paper Co., Ltd., Shin-Etsu Film Co., Ltd., and polyethylene terephthalate films such as PS series such as PS-25 manufactured by Teijin Limited. It is not limited to this.

  The thickness of the protective film is preferably 1 to 100 μm, more preferably 5 to 50 μm, still more preferably 5 to 30 μm, and particularly preferably 15 to 30 μm. If the thickness is less than 1 μm, the protective film tends to be broken during lamination, and if it exceeds 100 μm, the cost tends to be inferior.

  The photosensitive resin composition layer 12 is prepared by dissolving the photosensitive resin composition of the present invention in a solvent as described above to obtain a solution (coating solution) having a solid content of about 30 to 60% by mass, The coating liquid is preferably formed by coating on a support film and drying. The coating can be performed by a known method such as a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, or a bar coater. Drying can be performed at 70 to 150 ° C. for about 5 to 30 minutes. Moreover, it is preferable that the amount of the residual organic solvent in the photosensitive resin composition shall be 2 mass% or less from the point which prevents the spreading | diffusion of the organic solvent in a next process.

  Moreover, although the thickness of the photosensitive resin composition layer changes with uses, it is preferable that it is 1-100 micrometers by the thickness after drying, and it is more preferable that it is 1-50 micrometers. If the thickness is less than 1 μm, it tends to be difficult to apply industrially, and if it exceeds 100 μm, the effect of the present invention is reduced, and the adhesive force and resolution tend to decrease.

  Moreover, it is preferable that the transmittance | permeability with respect to the ultraviolet-ray with a wavelength of 365 nm is 5 to 75%, as for the photosensitive resin composition layer, it is more preferable that it is 7 to 60%, and it is especially preferable that it is 10 to 40%. If the transmittance is less than 5%, the adhesion tends to be inferior, and if it exceeds 75%, the resolution tends to be inferior. The transmittance can be measured by a UV spectrometer, and examples of the UV spectrometer include a 228A type W beam spectrophotometer manufactured by Hitachi, Ltd.

  The photosensitive resin composition layer formed by the above method has an O.D. for an exposure wavelength of 405 nm. D. A value of 0.20 to 0.80 is preferable, a value of 0.20 to 0.70 is more preferable, and a value of 0.25 to 0.65 is more preferable. O. of the photosensitive resin composition layer. D. When the value is within the above range, the photosensitive resin composition layer can obtain sufficient sensitivity and resolution when light having a wavelength of 400 to 450 nm is used as exposure light, and still has a good resist shape. be able to. O. above. D. If the value is less than 0.20, sufficient light cannot be absorbed to cause the polymerization reaction, and thus the sensitivity tends to be low. On the other hand, the above O.D. D. If the value exceeds 0.80, the sensitivity is high, but it is difficult for light to reach the bottom, so the curability of the bottom becomes worse, the resist shape after development becomes an inverted trapezoidal shape, and the resolution becomes worse. Tend.

  The photosensitive element of the present invention may further have an intermediate layer such as a cushion layer, an adhesive layer, a light absorption layer, and a gas barrier layer. Moreover, the obtained photosensitive element can be wound up and stored in the form of a sheet or a roll around a core. In addition, it is preferable to wind up so that a support body may become the 1st outer side at this time. An end face separator is preferably installed on the end face of the roll-shaped photosensitive element roll from the viewpoint of end face protection, and a moisture-proof end face separator is preferably installed from the viewpoint of edge fusion resistance. Moreover, as a packing method, it is preferable to wrap and package in a black sheet with low moisture permeability. Examples of the winding core include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, and ABS resin (acrylonitrile-butadiene-styrene copolymer).

(Method for forming resist pattern)
Next, the resist pattern forming method of the present invention will be described. When the above-described photosensitive element of the present invention is provided with a protective film, the resist pattern forming method of the present invention is gradually peeled off from the photosensitive resin composition layer and gradually simultaneously with this. First, the photosensitive resin composition layer is laminated on the circuit forming substrate by bringing the exposed surface portion of the photosensitive resin composition layer into close contact with the surface of the circuit forming substrate on which the circuit is to be formed. A second step of irradiating a predetermined portion of the photosensitive resin composition layer to be exposed to actinic rays to form an exposed portion, and then a third step of removing an unexposed portion other than the exposed portion. It is characterized by containing at least. The “circuit forming substrate” refers to a substrate including an insulating layer and a conductor layer formed on the insulating layer.

As a method of laminating the photosensitive resin composition layer on the circuit forming substrate in the first step, after removing the protective film, the photosensitive resin composition layer is used for circuit formation while heating the photosensitive resin composition layer. A method of laminating by pressing on a substrate is mentioned. In addition, it is preferable to laminate | stack this operation under pressure reduction from the viewpoint of adhesiveness and followable | trackability. In the lamination of the photosensitive element, the photosensitive resin composition layer and / or the circuit forming substrate is preferably heated to 70 to 130 ° C., and the pressure bonding pressure is about 0.1 to 1.0 MPa (1 to 10 kgf / cm). it is preferably about ^2), but not particularly limited to these conditions. Further, if the photosensitive resin composition layer is heated to 70 to 130 ° C. as described above, it is not necessary to pre-heat the circuit forming substrate in advance, but in order to further improve the laminating property, Pre-heat treatment of the substrate can also be performed.

  Examples of the method for forming the exposed portion in the second step include a method of irradiating an image with active light through a negative or positive mask pattern called an artwork (mask exposure method). At this time, when the support film present on the photosensitive resin composition layer is transparent to the active light, the active light can be irradiated through the support film, and when the support film is light-shielding After removing the support film, the photosensitive resin composition layer is irradiated with actinic rays. Actinic rays are also emitted by direct drawing methods such as laser direct drawing exposure methods and direct drawing methods in which a plurality of mirrors are arranged and the angle of each mirror is changed as necessary so that the exposure light becomes an image. You may employ | adopt the method of irradiating to an image form.

  As a direct drawing method in which the exposure light becomes an image by arranging a plurality of mirrors and changing the angle of each mirror as necessary, for example, a mirror of about 13 to 17 μm square is 480,000 to 800,000. There is a direct drawing method in which the exposure light is imaged by arranging approximately one and changing the angle of each mirror as necessary. More specifically, for example, “Digital Light Processing” exposure method (DLP (Digital Light Processing)) of Texas Instruments, “Data Direct Imaging System” of Pentax, “Masked Lithography System” of BALL Conductor (Maskless Lithography System) "and the like. The arrayed mirrors that perform the core function of the direct drawing method are referred to as “micromirror array”, “two-dimensional display element”, “DMD (Digital Mirror Device)”, and the like.

  As a light source of actinic light, a known light source, a known light source, for example, a carbon arc lamp, a mercury vapor arc lamp, a high pressure mercury lamp, a xenon lamp, an Ar ion laser, a semiconductor laser, or the like, effectively emits ultraviolet light, visible light, or the like. Things are used. In the present invention, light having a wavelength of 365 nm or less of a mercury lamp light source is cut by 90% (more preferably 99.0%, more preferably 99.5%) or more using a filter, actinic light having a wavelength of 400 to 450 nm ( More preferably, it is desirable to use light (active light) of 400 to 415 nm) or light (active light) of a semiconductor laser having a wavelength of 405 nm. As a filter for cutting light having a wavelength of 365 nm or less, for example, a sharp cut filter SCF-100S-39L manufactured by Sigma Kogyo Co., Ltd. can be used. Further, it is preferable to use a laser (more preferably a semiconductor laser diode, more preferably a gallium nitride semiconductor laser) or a blue laser (more preferably a gallium nitride blue laser) as a light source. It is preferable to irradiate light (active light) of ˜450 nm (more preferably, 400 to 415 nm).

  In the present embodiment, the light from the light source is preferably irradiated with light having a wavelength of 400 to 450 nm, and more preferably light having a wavelength of 400 to 415 nm. When a light source that emits a lot of light having a wavelength of 365 nm or less, such as a mercury lamp, is used as the exposure light, it is preferable to irradiate the light with a wavelength of 365 nm or less using a filter by cutting 90% or more, and 99.0% or more It is more preferable to cut, and it is particularly preferable to cut 99.5% or more. As a filter for cutting light having a wavelength of 365 nm or less, for example, a sharp cut filter SCF-100S-39L manufactured by Sigma Kogyo Co., Ltd. can be used. The light source is preferably a laser, more preferably a semiconductor laser diode, and particularly preferably a gallium nitride semiconductor laser and a blue laser. As the blue laser, a gallium nitride blue laser is preferable. Furthermore, when using a laser light source as exposure light, it is preferable to irradiate light having a wavelength of 400 to 450 nm, more preferably light having a wavelength of 400 to 415 nm, and particularly preferably light having a wavelength of 405 nm. In addition, the method of exposing by the direct drawing method in which the exposure light becomes an image by arranging about 480,000 to 800,000 mirrors of about 13 to 17 μm square and changing the angle of each mirror as necessary. It is preferably performed with light having a wavelength of 400 to 450 nm, more preferably light having a wavelength of 400 to 415 nm, and particularly preferably light having a wavelength of 400 to 410 nm.

  Moreover, it is also preferable to irradiate the light of the light source exemplified above with light whose area integrated intensity a at a wavelength of 400 nm to 450 nm in the oscillation spectrum of the light source is 10 times or more of the area integrated intensity b at a wavelength of 300 nm or more and less than 400 nm. . FIG. 3 is an oscillation spectrum diagram of a mercury lamp light source. When a mercury lamp is used as it is as a light source, the wavelength range of the emitted light is wide as shown in FIG. 3, and light having a wavelength of less than 400 nm, which is ultraviolet light harmful to the human body, centering on light (i-line) having a wavelength of 365 nm. Will be irradiated. Therefore, using a cut filter as shown in FIG. 4, the area integrated intensity of the oscillation spectrum having a wavelength of 300 nm to less than 400 nm, which is ultraviolet light harmful to the human body, is b, and the area integrated intensity of the irradiated light with a wavelength of 400 to 450 nm is When a is set, it is preferable to cut so that a is 10 times or more of b. Here, FIG. 4 is an oscillation spectrum diagram of a mercury lamp light source using a filter.

  Next, after the exposure, as a method of removing the portion other than the exposed portion in the third step, first, when the support film is present on the photosensitive resin composition layer, the support film is removed, and then Examples include a method in which a portion other than the exposed portion is removed by wet development, dry development, or the like. Thereby, a resist pattern is formed.

  For example, in the case of wet development, using a developer corresponding to a photosensitive resin composition such as an alkaline aqueous solution, an aqueous developer, an organic solvent developer, etc., for example, spraying, rocking immersion, brushing, scraping, etc. Development is performed by a known method.

  As the developing solution, a safe and stable solution having good operability such as an alkaline aqueous solution is used. Examples of the base of the alkaline aqueous solution include alkali hydroxides such as lithium, sodium, or potassium hydroxide, alkali carbonates such as lithium, sodium, potassium, or ammonium carbonate or bicarbonate, potassium phosphate, and phosphoric acid. Alkali metal phosphates such as sodium and alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate are used.

  Moreover, as alkaline aqueous solution used for image development, 0.1-5 mass% dilute solution of sodium carbonate, 0.1-5 mass% dilute solution of potassium carbonate, 0.1-5 mass% dilute solution of sodium hydroxide, A dilute solution of 0.1 to 5% by mass sodium tetraborate is preferred. Moreover, it is preferable to make pH of the alkaline aqueous solution used for image development into the range of 9-11, and the temperature is adjusted according to the developability of the photosensitive resin composition layer. In the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating development, and the like may be mixed.

  Examples of the aqueous developer include a developer composed of water or an alkaline aqueous solution and one or more organic solvents. Here, as the base of the alkaline aqueous solution, in addition to the substances described above, for example, borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1, 3 -Propanediol, 1,3-diaminopropanol-2, morpholine and the like. The pH of the developer is preferably as low as possible within a range where the resist can be sufficiently developed, preferably pH 8-12, more preferably pH 9-10.

  Examples of the organic solvent include triacetone alcohol, acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono And butyl ether. These are used alone or in combination of two or more. The concentration of the organic solvent is usually preferably 2 to 90% by mass, and the temperature can be adjusted according to the developability. Further, a small amount of a surfactant, an antifoaming agent or the like can be mixed in the aqueous developer. Examples of the organic solvent-based developer used alone include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone.

  These organic solvents preferably add water in the range of 1 to 20% by mass in order to prevent ignition. Moreover, you may use together 2 or more types of image development methods as needed. Development methods include a dip method, a battle method, a spray method, brushing, and slapping, and the high pressure spray method is most suitable for improving the resolution.

Examples of the development method include a dip method, a spray method, brushing, and slapping. As the treatment after development, the resist pattern may be further cured and used by heating at about 60 to 250 ° C. or exposure at about 0.2 to 10 J / cm ² as necessary. For the etching of the metal surface performed after development, for example, a cupric chloride solution, a ferric chloride solution, an alkaline etching solution, or the like can be used.

(Printed wiring board manufacturing method)
Next, the manufacturing method of the printed wiring board of this invention is demonstrated. The method for producing a printed wiring board of the present invention comprises etching or plating a circuit forming substrate on which a resist pattern is formed by the method for forming a resist pattern of the present invention.

  Etching and plating of the circuit forming substrate is performed on a conductor layer or the like of the circuit forming substrate using the formed resist pattern as a mask. Etching solutions used for etching include cupric chloride solution, ferric chloride solution, alkaline etching solution, and hydrogen peroxide etching solution. It is preferable to use an iron solution. Moreover, as a plating method in the case of plating, for example, copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high throw solder plating, watt bath (nickel sulfate-nickel chloride) plating, nickel sulfamate, etc. Nickel plating, hard gold plating, and gold plating such as soft gold plating.

  After completion of etching or plating, the resist pattern can be peeled off with a stronger alkaline aqueous solution than the alkaline aqueous solution used for development, for example. As this strongly alkaline aqueous solution, for example, a 1 to 10% by mass sodium hydroxide aqueous solution, a 1 to 10% by mass potassium hydroxide aqueous solution and the like are used. Examples of the peeling method include a dipping method and a spray method, and the dipping method and the spray method may be used alone or in combination. The printed wiring board on which the resist pattern is formed may be a multilayer printed wiring board or may have a small diameter through hole. A printed wiring board is obtained as described above.

  Hereinafter, preferred examples of the present invention will be described in more detail, but the present invention is not limited to these examples.

  First, the components shown in Table 1 and Table 2 were blended, and solutions of photosensitive resin compositions of Examples 1 to 3 and Comparative Examples 1 and 2 were obtained.

  Next, a solution of the obtained photosensitive resin composition (Examples 1 to 3 and Comparative Examples 1 and 2) was converted into a 16 μm-thick polyethylene terephthalate film (trade name GS-16, manufactured by Teijin Limited). It apply | coated uniformly on top and it dried for 10 minutes with a 100 degreeC hot-air convection dryer, and obtained the photosensitive element (Example 1- Example 3, and Comparative Example 1 and Comparative Example 2). The film thickness after drying of the photosensitive resin composition layer of each photosensitive element was 24 μm.

  Next, each photosensitive element (Examples 1 to 3 as well as Comparative Example 1 and Comparative Example 1) was compared using a UV spectrometer (manufactured by Hitachi, Ltd., trade name: “U-3310 spectrophotometer”). O. with respect to the exposure wavelength of the photosensitive resin composition layer of Example 2). D. The value was measured. O. D. Values are first measured by placing each photosensitive element consisting of a support film and a photosensitive resin composition layer on the measurement side, placing a support film on the reference side, and continuously measuring from 550 to 300 nm in the absorbance mode, at 365 nm and 405 nm. Was measured by reading. The results are shown in Table 3 below.

On the other hand, a brush equivalent to # 600 is applied to the copper surface of a copper clad laminate (product name: MCL-E-67, manufactured by Hitachi Chemical Co., Ltd.), which is a glass epoxy material in which copper foil (thickness 35 μm) is laminated on both sides. Polishing was performed using a polishing machine (manufactured by Sankei Co., Ltd.), washed with water, and then dried with an air flow to obtain a copper-clad laminate (substrate). Next, after heating to a copper clad laminate 80 ° C., the protective film of each photosensitive element (Examples 1 to 3 and Comparative Examples 1 and 2) is removed on the copper clad laminate. Then, each photosensitive resin composition layer was laminated (laminated) at 120 ° C. under a pressure of 0.4 MPa (4 kgf / cm ² ) so as to be in close contact with the surface of the copper-clad laminate.

  Next, when the copper clad laminate on which each photosensitive element is laminated is cooled to 23 ° C., the polyethylene terephthalate surface has a concentration region of 0.00 to 2.00, a concentration step of 0.05, and a tablet size. A phototool having a 41-step tablet with a size of 20 mm × 187 mm and each step size of 3 mm × 12 mm, and wiring with a line width / space width of 6/6 to 35/35 (unit: μm) as a negative for resolution evaluation A photo tool having a pattern was adhered. Next, a sharp cut filter SCF-100S-39L made by Sigma Kogyo Co., Ltd. is placed on it to cut 99.5% or more of light having a wavelength of 365 nm or less, and parallel light exposure using a 5 kW short arc lamp as a light source. Using a machine (manufactured by Oak Seisakusho, product name EXM-1201), exposure was performed with an exposure amount of 14 steps, 17 steps, and 20 steps after development of the 41 step tablet.

  The exposure amount at which the number of remaining steps after development of the 41-step tablet was 17 was defined as sensitivity. The illuminance is measured using an ultraviolet illuminometer (trade name: “UIT-101” manufactured by USHIO INC.) Using a 405 nm probe for light that has passed through the sharp cut filter. The amount.

  Next, the polyethylene terephthalate film was peeled off, and a 1% by mass sodium carbonate aqueous solution was sprayed at 30 ° C. for 24 seconds to remove unexposed portions. Then, the photosensitivity of the photosensitive resin composition was evaluated by measuring the number of steps of the step tablet of the photocured film formed on the copper-clad laminate. The results are shown in Table 3 below. The photosensitivity is indicated by the number of steps of the step tablet, and the higher the number of steps of the step tablet, the higher the photosensitivity.

  The resolution was evaluated based on the smallest value of the space width between the line widths in which the unexposed portions could be removed cleanly by the development process, and the lines were generated without meandering or chipping. The evaluation of sensitivity and resolution is better as the numerical value is smaller. The results are shown in Table 3 below.

  The resist shape after development was observed using a Hitachi scanning electron microscope S-500A. The resist shape is preferably close to a rectangle. The results are shown in Table 3 below.

  Next, the component shown in Table 4 and Table 5 was mix | blended, and the solution of the photosensitive resin composition of Example 4-Example 6 and Comparative Example 3 and Comparative Example 4 was obtained.

  Next, the obtained solutions of the photosensitive resin compositions of Examples 4 to 6 and Comparative Examples 3 to 4 were uniformly applied onto a 16 μm-thick polyethylene terephthalate film (product name: GS-16, manufactured by Teijin Limited). And a hot air convection dryer at 100 ° C. for 10 minutes to obtain a photosensitive element. The film thickness of the photosensitive resin composition layer was 25 μm.

  O. with respect to the exposure wavelength of the photosensitive resin composition layer in the obtained photosensitive element. D. Values were measured as in Example 1. Further, the sensitivity, resolution, and resist shape were evaluated in the same manner as in Example 1 except that the obtained photosensitive element was used. The illuminance measurements in Examples 4 to 6 and Comparative Examples 3 to 4 were measured using Ushio's UV integrated light meter UIT-150 and Ushio's light receiving instead of Ushio's UV illuminance meter UIT-101. The measurement was carried out using a combination of UVD-S405 and the instrument.

  The photosensitive elements of Examples 4 to 6 and Comparative Examples 3 to 4 were subjected to O.D. D. Table 6 shows data on values, sensitivity, resolution, and cross-sectional shape of the resist. For reference, the blending amount P [g] of the component (C) in the photosensitive resin composition, the film thickness Q [μm] of the photosensitive resin composition layer of the photosensitive element, and the product R thereof are also shown. .

  As can be seen from the results shown in the above table, it was confirmed that Examples 4 to 6 were excellent in sensitivity and resolution as compared with Examples 1 to 3, and the resist shape was substantially rectangular. In Examples 4 to 6, the sensitivity is a small value compared to Examples 1 to 3, but this is because the measurement equipment used for measuring the illuminance has changed and the amount of component (C) has been changed. It is believed that there is.

  The photosensitive element of the present invention can obtain sufficient sensitivity and resolution when light having a wavelength of 400 to 450 nm is used as exposure light, and can still obtain a good resist shape. Therefore, according to the photosensitive element of the present invention, it is possible to provide a resist pattern forming method and a printed wiring board manufacturing method using such a photosensitive element. More specifically, it is possible to provide a resist pattern forming method capable of obtaining sufficient sensitivity and resolution when using light having a wavelength of 400 to 450 nm as exposure light and still obtaining a good resist shape. It becomes possible. Furthermore, it is possible to provide a method for manufacturing a printed wiring board capable of manufacturing a high-density printed wiring board with high throughput when light having a wavelength of 400 to 450 nm is used as exposure light.

DESCRIPTION OF SYMBOLS 1 ... Photosensitive element, 11 ... Support film, 12 ... Photosensitive resin composition layer, 13 ... Protective film.

Claims (20)

A photosensitive element having a support film and a photosensitive resin composition layer disposed on the support film,
The photosensitive resin composition layer contains a photosensitive resin composition,
The photosensitive resin composition includes (A) a binder polymer, (B) a photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond, and (C) a photopolymerization initiator,
The (C) photopolymerization initiator contains at least 4,4′-bis (dialkylamino) benzophenone and / or 4,4′-bis (alkylamino) benzophenone as a constituent component,
The layer thickness Q [μm] of the photosensitive resin composition layer, the total mass Wa [g] of the (A) binder polymer in the photosensitive resin composition layer, and the above-mentioned in the photosensitive resin composition layer (B) The total mass Wb [g] of the photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond, and the 4,4′-bis (dialkylamino) benzophenone in the photosensitive resin composition layer And / or the mass Wc [g] of 4,4′-bis (alkylamino) benzophenone is adjusted so as to simultaneously satisfy the conditions represented by the following formulas (1) to (3),
A photosensitive element characterized by
P = {Wc / (Wa + Wb)} × 100 (1)
P × Q = R (2)
6.5 ≦ R ≦ 21.5 (3)   The 4,4′-bis (dialkylamino) benzophenone is 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (dimethylamino) benzophenone, or 4,4′-bis (methylethylamino) benzophenone. The photosensitive element according to claim 1, wherein The photosensitive element according to claim 1, wherein R satisfies a condition represented by the following formula (4).
7.2 ≦ R ≦ 20.0 (4) The photosensitive element according to claim 1, wherein R satisfies a condition represented by the following formula (5).
9.6 ≦ R ≦ 18.5 (5)   The photosensitive element according to claim 1, wherein the photosensitive element is exposed to light having a wavelength of 400 to 450 nm.   6. The photosensitive element according to claim 5, wherein the photosensitive resin composition of the photosensitive element has a property of being exposed to and polymerized by the light having a wavelength of 400 to 450 nm.   The photosensitive element according to claim 1, wherein the photosensitive element is exposed by light having a wavelength of 400 to 415 nm.   The photosensitive element according to claim 7, wherein the photosensitive resin composition of the photosensitive element has a property of being exposed to and polymerized by the light having a wavelength of 400 to 415 nm.   The photosensitive element as described in any one of Claims 1-8, Comprising: The photosensitive element exposed by the light emitted from a blue laser.   The photosensitive element according to claim 1, wherein the photosensitive element is exposed by light emitted from a gallium nitride based semiconductor laser.   It is a photosensitive element as described in any one of Claims 1-10, Comprising: A plurality of mirrors are arranged, and the exposure light is directly imaged by changing the angle of each mirror as necessary. Photosensitive element exposed by drawing method.   The photosensitive element as described in any one of Claims 1-10, Comprising: The photosensitive element exposed by the digital light processing exposure method.   The photosensitive element as described in any one of Claims 1-4, Comprising: The photosensitive element exposed by the actinic light which cut 90% or more of light with a wavelength of 365 nm or less.   The photosensitive resin composition of the photosensitive element has a property of being exposed to and polymerized with an actinic ray obtained by cutting 90% or more of the light having a wavelength of 365 nm or less. Photosensitive element.   5. The photosensitive element according to claim 1, wherein the integrated area intensity a of wavelengths 400 nm to 450 nm in the oscillation spectrum of the light source is 10 times or more of the integrated area intensity b of wavelengths 300 nm or more and less than 400 nm. A photosensitive element that is exposed by light. The portion of the surface opposite to the surface in contact with the support film in the photosensitive resin composition layer of the photosensitive element according to any one of claims 1 to 15, is a circuit of a circuit forming substrate. A first step of laminating the photosensitive resin composition layer on the circuit forming substrate by closely adhering to the surface to be formed;
A second step of irradiating a predetermined portion of the photosensitive resin composition layer to be exposed with an actinic ray to form an exposed portion;
Next, a third step of removing an unexposed portion other than the exposed portion;
Including at least,
A method of forming a resist pattern characterized by the above.   A method for manufacturing a printed wiring board, comprising etching or plating a circuit forming substrate on which a resist pattern is formed by the method for forming a resist pattern according to claim 16. A photosensitive element having a support film, a protective film made of a synthetic resin, and a photosensitive resin composition layer disposed between the support film and the protective film,
The photosensitive resin composition layer contains a photosensitive resin composition,
The photosensitive resin composition includes (A) a binder polymer, (B) a photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond, and (C) a photopolymerization initiator,
The (C) photopolymerization initiator contains at least 4,4′-bis (dialkylamino) benzophenone and / or 4,4′-bis (alkylamino) benzophenone as a constituent component,
The layer thickness Q [μm] of the photosensitive resin composition layer, the total mass Wa [g] of the (A) binder polymer in the photosensitive resin composition layer, and the above-mentioned in the photosensitive resin composition layer (B) The total mass Wb [g] of the photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond, and the 4,4′-bis (dialkylamino) benzophenone in the photosensitive resin composition layer And / or the mass Wc [g] of 4,4′-bis (alkylamino) benzophenone is adjusted so as to simultaneously satisfy the conditions represented by the following formulas (1) to (3),
A photosensitive element characterized by
P = {Wc / (Wa + Wb)} × 100 (1)
P × Q = R (2)
6.5 ≦ R ≦ 21.5 (3) The protective film of the photosensitive element according to claim 18 is gradually peeled from the photosensitive resin composition layer, and a portion of the surface of the photosensitive resin composition layer that is gradually exposed at the same time is formed as a circuit. A first step of laminating the photosensitive resin composition layer on the circuit forming substrate by closely contacting a surface of the forming substrate with a circuit to be formed;
A second step of irradiating a predetermined portion of the photosensitive resin composition layer to be exposed with an actinic ray to form an exposed portion;
Next, a third step of removing an unexposed portion other than the exposed portion;
Including at least,
A method of forming a resist pattern characterized by the above. A method for manufacturing a printed wiring board, comprising etching or plating a circuit forming substrate on which a resist pattern is formed by the method for forming a resist pattern according to claim 19.

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