JP2017040710A - Photosensitive resin composition, photosensitive element, method for forming resist pattern and method for manufacturing printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition from which a resist pattern excellent in all of resolution, adhesiveness and flexibility can be formed, and a photosensitive element, a method for forming a resist pattern and a method for manufacturing a printed wiring board using the above composition.SOLUTION: The photosensitive resin composition comprises: (A) a binder polymer having a structural unit derived from a (meth)acrylic acid, a structural unit derived from a benzyl (meth)acrylate, and a structural unit derived from a (meth)acrylic acid hydroxyalkyl ester having a hydroxyalkyl group having 1 to 12 carbon atoms; (B) a photopolymerizable compound comprising a bisphenol type di(meth)acrylate having 1 to 4 ethyleneoxy group structural units; and (C) a photopolymerization initiator.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photosensitive resin composition, a photosensitive element, a resist pattern forming method, and a printed wiring board manufacturing method.

  In the field of manufacturing printed wiring boards, a photosensitive resin composition is widely used as a resist material used for etching treatment or plating treatment. A photosensitive resin composition includes a support and a layer (hereinafter, also referred to as “photosensitive resin composition layer”) formed using the photosensitive resin composition on the support. Often used as a body).

A printed wiring board is manufactured as follows, for example.
First, a photosensitive element having a support and a photosensitive resin composition layer is prepared, and a photosensitive resin composition layer of the photosensitive element is formed on a circuit forming substrate (photosensitive layer forming step). Next, after peeling off and removing the support, the exposed portion is cured by irradiating a predetermined portion of the photosensitive resin composition layer with actinic rays (exposure step). Thereafter, by removing (developing) the unexposed portions from the substrate, a resist pattern that is a cured product of the photosensitive resin composition (hereinafter also referred to as “resist cured product”) is formed on the substrate (development). Process). An etching process or a plating process is performed on the obtained resist pattern to form a circuit on the substrate (circuit forming process), and finally the resist is peeled and removed to produce a printed wiring board (peeling process).

  As an exposure method, conventionally, a method of exposing via a photomask using a mercury lamp as a light source has been used. In recent years, a direct drawing exposure method called DLP (Digital Light Processing) or LDI (Laser Direct Imaging), which directly draws on a photosensitive resin composition layer without using a photomask based on digital data of a pattern, has been proposed. ing. This direct drawing exposure method is being introduced for the production of a high-density package substrate because it has better alignment accuracy than the exposure method through a photomask and a high-definition pattern can be obtained.

  In general, in the exposure process, it is desired to shorten the exposure time in order to improve production efficiency. However, in the above-described direct drawing exposure method, in addition to using monochromatic light such as a laser as a light source and irradiating a light beam while scanning the substrate, a long exposure time is required as compared with an exposure method using a conventional photomask. Tend. Therefore, in order to shorten the exposure time and increase the production efficiency, it is necessary to improve the sensitivity of the photosensitive resin composition than before.

  On the other hand, with the recent increase in the density of printed wiring boards, there is an increasing demand for a photosensitive resin composition capable of forming a resist pattern excellent in resolution (resolution) and adhesion. In particular, a photosensitive resin composition capable of forming a resist pattern having an L / S (line width / space width) of 10/10 (unit: μm) or less in package substrate production is required.

  In general, higher resolution of the resist pattern is achieved, for example, by improving the crosslinking density after curing of the photosensitive resin composition. However, when the crosslink density is improved, the resist pattern becomes hard and brittle, and the problem of lack of the resist pattern in the transport process or the like is likely to occur. As a method for solving this problem, there is a technique for improving the flexibility (flexibility) of the resist pattern. However, when the flexibility is improved, the resist pattern tends to collapse, and as a result, the resolution tends to decrease. Therefore, it can be said that high resolution and flexibility (flexibility) of the resist pattern to be formed are mutually contradictory characteristics.

  Conventionally, various photosensitive resin compositions have been studied in response to these requirements. For example, in Patent Documents 1 to 8, there is a photosensitive resin composition that improves the above-described required characteristics by using a specific binder polymer, photopolymerizable compound, photopolymerization initiator, and sensitizing dye. It is disclosed.

JP-A-2005-301101 JP 2007-114452 A JP 2007-1222028 A JP 2011-081031 A International Publication No. 08/078483 International Publication No. 10/098175 International Publication No. 10/098183 International Publication No. 12/067107

  However, the conventional photosensitive resin composition still has room for improvement in terms of improving the flexibility while maintaining the resolution and adhesion of the resist pattern to be formed.

  The present invention relates to a photosensitive resin composition capable of forming a resist pattern excellent in all of resolution, adhesion and flexibility, a photosensitive element using the same, a method for forming a resist pattern, and a method for producing a printed wiring board. The purpose is to provide.

  As a result of intensive studies to solve the above problems, the present inventors have found that a structural unit derived from (meth) acrylic acid, a structural unit derived from benzyl (meth) acrylate, and a hydroxy group having 1 to 12 carbon atoms. A binder polymer having a structural unit derived from a hydroxyalkyl ester of (meth) acrylic acid having an alkyl group, an ethyleneoxy group having 1 to 4 structural units, a bisphenol-type structure and two ethylenically unsaturated bonding groups It has been found that a photosensitive resin composition capable of forming a resist pattern excellent in all of resolution, adhesion, and flexibility can be obtained by combining with a photopolymerizable compound having the present invention, and the present invention has been completed. .

  That is, the first aspect of the present invention has (A) a structural unit derived from (meth) acrylic acid, a structural unit derived from benzyl (meth) acrylate, and a hydroxyalkyl group having 1 to 12 carbon atoms ( (B) a photopolymerizable compound comprising a binder polymer having a structural unit derived from a hydroxyalkyl ester of acrylic acid, and (B) a bisphenol-type di (meth) acrylate having 1 to 4 structural units of ethyleneoxy group; C) a photopolymerization initiator.

  When the photosensitive resin composition takes the above-described embodiment, a resist pattern that is excellent in resolution, adhesion, and flexibility can be formed. According to the photosensitive resin composition, a resist pattern having L / S (line width / space width) of 10/10 (unit: μm) or less can be formed.

  2nd aspect of this invention is a photosensitive element provided with a support body and the photosensitive resin composition layer formed from the photosensitive resin composition of the 1st aspect provided on the said support body. . By using such a photosensitive element, it is possible to efficiently form a resist pattern that is particularly excellent in resolution, adhesion, and flexibility.

  According to a third aspect of the present invention, there is provided a photosensitive layer forming step of forming a photosensitive resin composition layer on the substrate using the photosensitive resin composition of the first aspect, and at least one of the photosensitive resin composition layers. An exposure step of irradiating a part of the region with actinic rays and photocuring the region to form a cured product region, and removing regions other than the cured product region of the photosensitive resin composition layer from the substrate And a developing process for forming a resist pattern which is the cured product region on the substrate. According to this resist pattern forming method, it is possible to efficiently form a resist pattern having excellent resolution, adhesion, and flexibility.

  In the method for forming a resist pattern, the wavelength of active light to be irradiated is preferably in the range of 340 to 430 nm. Thereby, a resist pattern with better resolution, adhesion, flexibility and resist shape can be formed more efficiently with excellent sensitivity.

  A fourth aspect of the present invention is a method for manufacturing a printed wiring board including a step of etching or plating a substrate on which a resist pattern has been formed by the method for forming a resist pattern. According to this manufacturing method, a printed wiring board having high-density wiring such as a high-density package substrate can be efficiently manufactured with excellent accuracy and high productivity.

  ADVANTAGE OF THE INVENTION According to this invention, the photosensitive resin composition which can form the resist pattern which is excellent in all of resolution, adhesiveness, and a flexibility with the developability outstanding can be provided. In addition, a photosensitive element using this photosensitive resin composition, a resist pattern forming method, and a printed wiring board manufacturing method can form a resist pattern that is excellent in resolution, adhesion, and flexibility. A printed wiring board having high-density wiring such as a package substrate can be efficiently manufactured with excellent accuracy and high productivity.

It is a schematic cross section which shows one Embodiment of the photosensitive element of this invention. It is a perspective view which shows typically an example of the manufacturing process of the printed wiring board by a semi-additive construction method.

Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the present specification, (meth) acrylic acid means acrylic acid or methacrylic acid, (meth) acrylate means acrylate or the corresponding methacrylate, and (meth) acryloyloxy group means An acryloyloxy group or a methacryloyloxy group is meant. The (poly) ethyleneoxy group means at least one of an ethyleneoxy group or a polyethyleneoxy group in which an ethyleneoxy group or two or more ethylene groups are connected by an ether bond. The ethyleneoxy group is a group represented by (—CH ₂ CH ₂ —O—) and is also referred to as an oxyethylene group or ethylene oxide. The (poly) propyleneoxy group means at least one of a propyleneoxy group or a polypropyleneoxy group in which a propyleneoxy group or two or more propylene groups are linked by an ether bond. The propyleneoxy group is a group represented by (—CHCH ₃ CH ₂ —O—), a group represented by (—CH ₂ CHCH ₃ —O—), or (—CH ₂ CH ₂ CH ₂ —O). -) And is also referred to as an oxypropylene group or propylene oxide. Furthermore, “EO-modified” means a compound having a (poly) ethyleneoxy group, and “PO-modified” means a compound having a (poly) propyleneoxy group. “PO-modified” means a compound having both a (poly) ethyleneoxy group and a (poly) propyleneoxy group.

  In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. . Moreover, the numerical range shown using "to" shows the range which includes the numerical value described before and behind "to" as a minimum value and a maximum value, respectively. Furthermore, the content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. Further, the term “layer” includes a structure formed in a part in addition to a structure formed over the entire surface when observed as a plan view. Further, the term “lamination” indicates that the layers are stacked, and two or more layers may be bonded, or two or more layers may be detachable.

<Photosensitive resin composition>
The photosensitive resin composition of this embodiment comprises (A) component: a structural unit derived from (meth) acrylic acid, a structural unit derived from benzyl (meth) acrylate, and a hydroxyalkyl group having 1 to 12 carbon atoms. Photopolymerizability comprising a binder polymer having a structural unit derived from a hydroxyalkyl ester having (meth) acrylic acid and a bisphenol type di (meth) acrylate having (B) component: 1 to 4 structural units of ethyleneoxy group A compound and (C) component: a photoinitiator are contained. The photosensitive resin composition may further contain other components as necessary.

  A structural unit derived from (meth) acrylic acid, a structural unit derived from benzyl (meth) acrylate, and a structural unit derived from a (meth) acrylic acid hydroxyalkyl ester having a hydroxyalkyl group having 1 to 12 carbon atoms. Resist pattern excellent in all of resolution, adhesion, and flexibility by including a binder polymer and a bisphenol-type di (meth) acrylate having 1 to 4 structural units of ethyleneoxy group as a photopolymerizable compound The photosensitive resin composition which can form can be comprised. Although the detailed reason for the above effect is not necessarily clear, it can be considered as follows. In addition to structural units derived from benzyl (meth) acrylate that is hydrophobic and effective for low swelling, (meth) acrylic acid hydroxyalkyl ester having a hydroxyalkyl group having 1 to 12 carbon atoms and excellent flexibility By having the derived structural unit, it is assumed that a flexible resist pattern (cured film) can be formed while having low swellability, and the contradictory properties of adhesion and flexibility can be improved in a balanced manner. The Furthermore, it is assumed that the resolution is improved by combining the binder polymer and the photopolymerizable compound.

Component (A): Binder polymer The photosensitive resin composition has at least one structural unit derived from (meth) acrylic acid represented by the following general formula (1) as the component (A), the following general formula: A (meth) acrylic acid hydroxyalkyl ester having a structural unit derived from benzyl (meth) acrylate represented by (2) and a hydroxyalkyl group having 1 to 12 carbon atoms represented by the following general formula (3) A binder polymer having at least one type of structural unit derived from (hereinafter also referred to as “specific binder polymer”). The component (A) may further contain a binder polymer other than the specific binder polymer as necessary.

In the general formula (1) to ^(3), the R 1, ^{R 2} and ^{R 3} each independently represent a hydrogen atom or a methyl group, preferably ^{R 1} and ^{R 3} are both methyl group, ^{R 2} is A hydrogen atom is preferred. In the general formula (3), R ⁴ is an alkylene group having 1 to 12 carbon atoms, and the OH group can be bonded to any position of R ⁴ .

  The content of the structural unit derived from benzyl (meth) acrylate in the specific binder polymer is based on the total mass of the polymerizable monomers constituting the specific binder polymer in terms of excellent adhesion and peelability. It is preferably 10 to 80% by mass, more preferably 15 to 70% by mass, and still more preferably 20 to 60% by mass. From the viewpoint of excellent adhesion, the content is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more. Moreover, from the point which is excellent in peelability, it is preferable that this content rate is 80 mass% or less, It is more preferable that it is 70 mass% or less, It is still more preferable that it is 60 mass% or less.

  The content of the structural unit derived from the hydroxyalkyl ester of (meth) acrylic acid having a hydroxyalkyl group having 1 to 12 carbon atoms in the specific binder polymer constitutes the specific binder polymer from the point of excellent resolution and peelability. It is preferable that it is 1-50 mass% on the basis of the total mass of the polymerizable monomer to perform, It is more preferable that it is 2-30 mass%, It is still more preferable that it is 2-20 mass%. From the viewpoint of excellent resolution, the content is preferably 50% by mass or less, more preferably 30% by mass or less, further preferably 20% by mass or less, and 15% by mass or less. Is particularly preferable, and it is very preferably 10% by mass or less. Moreover, from the point which is excellent in peelability and adhesiveness, it is preferable that this content rate is 1 mass% or more, It is more preferable that it is 2 mass% or more, It is further more preferable that it is 3 mass% or more.

  The hydroxylalkyl group of the (meth) acrylic acid hydroxyalkyl ester is a hydroxyalkyl group having 1 to 12 carbon atoms, preferably a hydroxyalkyl group having 1 to 8 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms. Are more preferable, and a hydroxyalkyl group having 1 to 4 carbon atoms is still more preferable. By setting it as such a range, the resolution, adhesiveness, and flexibility can be improved with good balance. Further, when the number of carbon atoms is 4 or less, the resolution can be further improved.

  The specific binder polymer may have other structural units other than the above structural units. Examples of other structural units include structural units derived from the following other polymerizable monomers.

  Other polymerizable monomers can be polymerized with (meth) acrylic acid, benzyl (meth) acrylate and hydroxyalkyl (meth) acrylate, and (meth) acrylic acid, benzyl (meth) acrylate and If it is a polymerizable monomer different from (meth) acrylic acid hydroxyalkyl ester, there will be no restriction | limiting in particular. Other polymerizable monomers include (meth) acrylic acid alkyl ester, (meth) acrylic acid cycloalkyl ester, (meth) acrylic acid furfuryl, (meth) acrylic acid tetrahydrofurfuryl, (meth) acrylic acid isobornyl, Adamantyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, 2,2,2-trifluoroethyl (Meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, (meth) acrylate dicyclopentenyloxyethyl, (meth) acrylate dicyclopentanyloxyethyl, (meth) acrylate iso Bornyloxyethyl, (meth) acrylic acid Chlohexyloxyethyl, adamantyloxyethyl (meth) acrylate, dicyclopentenyloxypropyloxyethyl (meth) acrylate, dicyclopentanyloxypropyloxyethyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate (Meth) acrylic acid esters such as propyloxyethyl, adamantyloxypropyloxyethyl (meth) acrylate; α-bromoacrylic acid, α-chloroacrylic acid, β-furyl (meth) acrylic acid, β-styryl (meth) (Meth) acrylic acid derivatives such as acrylic acid; polymerizable styrene derivatives substituted at the α-position or aromatic ring such as styrene, vinyltoluene, α-methylstyrene; acrylamide such as diacetone acrylamide; acrylonitrile; vinyl − -Ether compounds of vinyl alcohol such as butyl ether; maleic acid; maleic anhydride; maleic acid monoesters such as monomethyl maleate, monoethyl maleate, monoisopropyl maleate; fumaric acid, cinnamic acid, α-cyanocinnamic acid, And unsaturated carboxylic acid derivatives such as itaconic acid, crotonic acid and propiolic acid. These can be used alone or in any combination of two or more.

  Moreover, it is preferable that a binder polymer further has the structural unit derived from the (meth) acrylic-acid alkylester from a viewpoint of improving developability and a peeling characteristic.

  The (meth) acrylic acid alkyl ester is preferably a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms, more preferably a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms. preferable. Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (meth) Hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate and (meth) ) Dodecyl acrylate. These can be used individually by 1 type or in combination of 2 or more types.

  When the specific binder polymer has a structural unit derived from a (meth) acrylic acid alkyl ester, the content of the polymerizable monomer constituting the binder polymer is more excellent in peelability, resolution and adhesion. It is preferable that it is 1-30 mass% on the basis of the total mass (100 mass%), It is more preferable that it is 1-20 mass%, It is still more preferable that it is 2-10 mass%. In terms of excellent peelability, the content is preferably 1% by mass or more, and more preferably 2% by mass or more. In view of excellent resolution and adhesion, the content is preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 10% by mass or less.

  Specific binder polymers include, for example, (meth) acrylic acid, benzyl (meth) acrylate, hydroxyalkyl ester of (meth) acrylic acid, and other polymerizable monomers used as necessary. The polymer is obtained by radical polymerization according to a conventional method.

  As the component (A), one type of specific binder polymer may be used alone, or two or more types of specific binder polymers may be used in any combination. Moreover, you may use other binder polymers other than a specific binder polymer with a specific binder polymer.

  The acid value of the binder polymer is preferably 90 to 250 mgKOH / g, more preferably 100 to 240 mgKOH / g, and more preferably 120 to 235 mgKOH / g in terms of excellent balance between developability and adhesion. Is more preferable, and it is especially preferable that it is 130-230 mgKOH / g. From the viewpoint of further shortening the development time, the acid value is preferably 90 mgKOH / g or more, more preferably 100 mgKOH / g or more, further preferably 120 mgKOH / g or more, and 130 mgKOH / g or more. It is particularly preferred that Further, from the viewpoint of further improving the adhesion of the cured product of the photosensitive resin composition, the acid value is preferably 250 mgKOH / g or less, more preferably 240 mgKOH / g or less, and 235 mgKOH / g or less. More preferably, it is particularly preferably 230 mgKOH / g or less.

  When the weight average molecular weight (Mw) of the binder polymer is measured by gel permeation chromatography (GPC) (converted by a calibration curve using standard polystyrene), it is 10,000 to 200,000 in terms of excellent balance between developability and adhesion. It is preferable that it is 15000-100000, It is further more preferable that it is 20000-80000, It is especially preferable that it is 23000-60000. In terms of excellent developability, it is preferably 200000 or less, more preferably 100000 or less, still more preferably 80000 or less, and particularly preferably 60000 or less. In terms of excellent adhesion, it is preferably 10,000 or more, more preferably 15,000 or more, further preferably 20,000 or more, particularly preferably 23,000 or more, and extremely preferably 25,000 or more. .

  The degree of dispersion (weight average molecular weight / number average molecular weight) of the binder polymer is preferably 3.0 or less, more preferably 2.8 or less, in view of further excellent resolution and adhesion. More preferably, it is as follows.

  The binder polymer may have, in the molecule, a characteristic group having photosensitivity to light having a wavelength in the range of 340 to 430 nm as necessary. Examples of the characteristic group include a group constituted by removing at least one hydrogen atom from a sensitizing dye described later.

  The content of the component (A) in the photosensitive resin composition is 30 to 70 parts by mass in the total amount of 100 parts by mass of the component (A) and the component (B) in terms of improving film formability, sensitivity, and resolution. It is preferable that it is 35-65 mass parts, and it is still more preferable that it is 40-60 mass parts. From the viewpoint of formability of the film (photosensitive resin composition layer), the content is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, and 40 parts by mass or more. Further preferred. In view of sufficiently obtaining sensitivity and resolution, the content is preferably 70 parts by mass or less, more preferably 65 parts by mass or less, and still more preferably 60 parts by mass or less.

(B) Component: Photopolymerizable Compound Next, the photopolymerizable compound (hereinafter also referred to as “component (B)”) will be described. The photopolymerizable compound as component (B) must contain at least one bisphenol di (meth) acrylate (hereinafter also referred to as “specific polymerizable compound”) having 1 to 4 structural units of ethyleneoxy group. Contains as an ingredient. The component (B) may further contain a photopolymerizable compound other than bisphenol-type di (meth) acrylate as necessary.

  In the specific polymerizable compound, the number of structural units of the ethyleneoxy group is 1 to 4. Here, the number of structural units of the ethyleneoxy group can be said to indicate how much ethylene oxide is added in the molecule. Therefore, an integer value is shown for a single molecule, but a rational number that is an average value is shown as an aggregate of a plurality of types of molecules.

  The specific polymerizable compound is preferably a compound represented by the following general formula (1a).

In general formula (1a), R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group. XO each independently represents an ethyleneoxy group.
(XO) m ₁ and (XO) m ₂ each represent a (poly) ethyleneoxy group. m ₁ and m ₂ may each independently take a numerical value of 0 to 4. m < ₁ > + m < ₂ > is 1-4. m ₁ and m ₂ represent the number of structural units. Therefore, an integer value is shown in a single molecule, and a rational number that is an average value is shown as an aggregate of a plurality of types of molecules. Hereinafter, the same applies to the number of structural units.

  Commercially available products of the above compounds include 2,2-bis (4- (methacryloxydiethoxy) phenyl) propane (manufactured by Hitachi Chemical Co., Ltd., “FA-324M”, etc.), 2,2-bis (4- (methacrylic). Roxyethoxy) phenyl) propane (ethylene oxide average 2.6 mol adduct) (manufactured by Shin-Nakamura Chemical Co., Ltd., “BPE-100”, etc.).

  The content of the specific polymerizable compound (component (B)) in the photosensitive resin composition is the components (A) and (B) from the viewpoint of suppressing swelling by suppressing molecular motion in the crosslinked network after photocuring. The total amount is preferably 1 to 60 parts by mass, more preferably 5 to 55 parts by mass, and still more preferably 10 to 50 parts by mass.

  The photosensitive resin composition can contain other photopolymerizable compounds other than a specific polymerizable compound as (B) component. Other photopolymerizable compounds are not particularly limited as long as photopolymerization is possible. The other photopolymerizable compound is preferably a compound having an ethylenically unsaturated bond. The compound having an ethylenically unsaturated bond includes a compound having one ethylenically unsaturated bond in the molecule, a compound having two ethylenically unsaturated bonds in the molecule, and three ethylenically unsaturated bonds in the molecule. Examples thereof include the compounds described above.

  When the component (B) contains other photopolymerizable compound, the content of the specific polymerizable compound in the component (B) is (B) from the viewpoint of physically suppressing swelling due to the bulkiness in the crosslinked network. It is preferable that it is 1-60 mass parts in 100 mass parts of total amounts of a component, It is more preferable that it is 6-50 mass parts, It is still more preferable that it is 10-40 mass parts.

  (B) It is preferable that a component contains at least 1 sort (s) of the compound which has two ethylenically unsaturated bonds in a molecule | numerator as another photopolymerizable compound. When (B) component contains the compound which has two ethylenically unsaturated bonds in a molecule | numerator as another photopolymerizable compound, the content is in 100 mass parts of total amount of (A) component and (B) component. 5 to 60 parts by mass, more preferably 5 to 55 parts by mass, and still more preferably 10 to 50 parts by mass.

  Examples of the compound having two ethylenically unsaturated bonds in the molecule include a bisphenol type di (meth) acrylate compound, a hydrogenated bisphenol A type di (meth) acrylate compound different from the specific polymerizable compound, and a urethane in the molecule. Examples include di (meth) acrylate compounds having a bond, polyalkylene glycol di (meth) acrylate having both (poly) ethyleneoxy group and (poly) propyleneoxy group in the molecule, and trimethylolpropane di (meth) acrylate. It is done.

  When the photosensitive resin composition further contains a bisphenol-type di (meth) acrylate compound different from the specific polymerizable compound as the component (B), the content thereof is 100 mass of the total amount of the component (A) and the component (B). It is preferable that it is 1-50 mass parts in a part, It is more preferable that it is 5-50 mass parts, It is still more preferable that it is 10-45 mass parts.

  Examples of the hydrogenated bisphenol A type di (meth) acrylate compound include 2,2-bis (4- (methacryloxypentaethoxy) cyclohexyl) propane. When the photosensitive resin composition contains a hydrogenated bisphenol A type di (meth) acrylate compound, the content thereof is 1 to 50 parts by mass in 100 parts by mass of the total amount of the component (A) and the component (B). It is preferable that it is 5 to 40 parts by mass.

  The component (B) preferably contains at least one polyalkylene glycol di (meth) acrylate as another photopolymerizable compound from the viewpoint of improving the flexibility of the resist pattern. When the photosensitive resin composition contains polyalkylene glycol di (meth) acrylate, the content thereof is 5 to 30 parts by mass in 100 parts by mass of the total amount of the component (A) and the component (B). Preferably, it is 10-25 mass parts.

  As the polyalkylene glycol di (meth) acrylate compound, polyalkylene glycol di (meth) acrylate having both a (poly) ethyleneoxy group and a (poly) propyleneoxy group in the molecule is preferable. In the molecule of the polyalkylene glycol di (meth) acrylate, the (poly) ethyleneoxy group and the (poly) propyleneoxy group may be successively present in blocks or randomly. The propyleneoxy group in the (poly) propyleneoxy group may be either an n-propyleneoxy group or an isopropyleneoxy group. In the (poly) isopropyleneoxy group, the secondary carbon of the propylene group may be bonded to an oxygen atom, or the primary carbon may be bonded to an oxygen atom.

  Polyalkylene glycol di (meth) acrylate is (poly) n-butyleneoxy group, (poly) isobutyleneoxy group, (poly) n-pentyleneoxy group, (poly) hexyleneoxy group, structural isomers thereof, etc. (Poly) alkyleneoxy group having about 4 to 6 carbon atoms.

  The component (B) may contain at least one photopolymerizable compound having three or more ethylenically unsaturated bonds in the molecule as another photopolymerizable compound.

  Examples of the compound having three or more ethylenically unsaturated bonds include trimethylolpropane tri (meth) acrylate and EO-modified trimethylolpropane tri (meth) acrylate (those having 1 to 5 structural units of ethyleneoxy group). , PO-modified trimethylolpropane tri (meth) acrylate, EO / PO-modified trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) acrylate and tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate EO-modified pentaerythritol tetra (meth) acrylate or dipentaerythritol hexa (meth) acrylate. These can be used alone or in combination of two or more.

  Among the compounds having three or more ethylenically unsaturated bonds, commercially available compounds include tetramethylol methane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., “A-TMM-3”, etc.), EO Modified trimethylolpropane trimethacrylate (manufactured by Hitachi Chemical Co., Ltd., “TMPT21E”, “TMPT30E”, etc.), pentaerythritol triacrylate (manufactured by Sartomer Co., Ltd., “SR444”, etc.), dipentaerythritol hexaacrylate (Shin Nakamura Chemical Co., Ltd.) And EO-modified pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., “ATM-35E”, etc.)).

  When the component (B) contains a photopolymerizable compound having three or more ethylenically unsaturated bonds in the molecule as the other photopolymerizable compound, the content is determined by resolution, adhesion, resist shape, and after curing. From the viewpoint of improving the peeling properties in a well-balanced manner, the total amount of the component (A) and the component (B) is preferably 3 to 30 parts by mass, more preferably 5 to 25 parts by mass, More preferably, it is 5-20 mass parts.

  Component (B) is an ethylenically unsaturated bond in the molecule as another photopolymerizable compound from the viewpoint of improving the resolution, adhesion, resist shape, and release properties after curing in a well-balanced manner, or suppressing scum generation. The photopolymerizable compound which has one may be included.

  Examples of the photopolymerizable compound having one ethylenically unsaturated bond in the molecule include nonylphenoxypolyethyleneoxyacrylate, phthalic acid compounds, and (meth) acrylic acid alkyl esters. Among the above, it is preferable that nonylphenoxypolyethyleneoxyacrylate or a phthalic acid compound is included from the viewpoint of improving the resolution, adhesion, resist shape, and release property after curing in a well-balanced manner.

  When (B) component contains the photopolymerizable compound which has one ethylenically unsaturated bond in a molecule | numerator as another photopolymerizable compound, the content is 100 mass of total of (A) component and (B) component. It is preferable that it is 1-20 mass parts in a part, It is more preferable that it is 3-15 mass parts, It is still more preferable that it is 5-12 mass parts.

  The content of the entire component (B) in the photosensitive resin composition is preferably 30 to 70 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B), and 35 to 65 parts by mass. More preferably, it is more preferably 35 to 50 parts by mass. When the content is 30 parts by mass or more, sufficient sensitivity and resolution tend to be easily obtained. When it is 70 parts by mass or less, a film (photosensitive resin composition layer) tends to be easily formed, and a good resist shape tends to be easily obtained.

Component (C): Photopolymerization initiator The photosensitive resin composition contains at least one photopolymerization initiator as the component (C). There is no restriction | limiting in particular as a photoinitiator which is (C) component, It can select suitably from the photoinitiator used normally. As the photopolymerization initiator, benzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino- Aromatic ketones such as propanone-1; quinone compounds such as alkylanthraquinones; benzoin ether compounds such as benzoin alkyl ethers; benzoin compounds such as benzoin and alkylbenzoins; benzyl derivatives such as benzyldimethyl ketal; 2- (2-chlorophenyl)- 2,4,5-triarylimidazole dimer such as 4,5-diphenylimidazole dimer, 2- (2-fluorophenyl) -4,5-diphenylimidazole dimer; 9-phenylacridine, 1, Acridine such as 7- (9,9'-acridinyl) heptane Conductor, and the like. These can be used alone or in combination of two or more.

  The component (C) preferably contains at least one 2,4,5-triarylimidazole dimer from the viewpoint of improving sensitivity and adhesion, and 2- (2-chlorophenyl) -4,5- More preferably, it contains a diphenylimidazole dimer. The 2,4,5-triarylimidazole dimer may be symmetric or asymmetric in structure.

  It is preferable that content of (C) component in the photosensitive resin composition is 0.1-10 mass parts with respect to 100 mass parts of total amounts of (A) component and (B) component, and 1-7 mass parts It is more preferable that it is 2-6 mass parts, It is still more preferable that it is 3-5 mass parts. When the content of the component (C) is 0.1 parts by mass or more, good sensitivity, resolution, or adhesion tends to be obtained, and when it is 10 parts by mass or less, a good resist shape is easily obtained. Tend.

  The photosensitive resin composition of the present invention preferably contains (D) a sensitizing dye and / or (E) a hydrogen donor in addition to the components (A) to (C) described above.

(D) component: Sensitizing dye It is preferable that the photosensitive resin composition contains at least 1 sort (s) of a sensitizing dye as (D) component. The sensitizing dye is capable of effectively utilizing the absorption wavelength of actinic rays used for exposure, and is preferably a compound having a maximum absorption wavelength of 340 to 430 nm.

  Examples of sensitizing dyes include pyrazoline compounds, anthracene compounds, coumarin compounds, xanthone compounds, oxazole compounds, benzoxazole compounds, thiazole compounds, benzothiazole compounds, triazole compounds, stilbene compounds, triazine compounds, thiophene compounds, and naphthalimide compounds. It is done. In particular, a pyrazoline compound or an anthracene compound is preferably included from the viewpoint of improving resolution, adhesion, and sensitivity. (D) The sensitizing dye which is a component can be used individually by 1 type or in combination of 2 or more types.

  When the photosensitive resin composition contains the component (D), the content of the component (D) in the photosensitive resin composition is 0.01 with respect to 100 parts by mass of the total amount of the components (A) and (B). It is preferable to set it as 10-10 mass parts, It is more preferable to set it as 0.05-5 mass parts, It is still more preferable to set it as 0.1-3 mass parts. When the content is 0.01 parts by mass or more, sensitivity and resolution tend to be easily obtained. When the content is 10 parts by mass or less, a sufficiently good resist shape tends to be easily obtained.

(E) Component: Hydrogen donor The photosensitive resin composition is photopolymerized during the reaction of the exposed portion as the (E) component in order to improve the contrast between the exposed portion and the unexposed portion (also referred to as “imaging”). It preferably contains at least one hydrogen donor capable of providing hydrogen to the initiator. Examples of the hydrogen donor include bis [4- (dimethylamino) phenyl] methane, bis [4- (diethylamino) phenyl] methane, and leucocrystal violet. These can be used alone or in combination of two or more.

  When the photosensitive resin composition contains the component (E), the content is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). It is more preferable to set it as 0.05-5 mass parts, and it is still more preferable to set it as 0.1-2 mass parts. If this content is 0.01 parts by mass or more, sufficient sensitivity tends to be obtained. If the amount is 10 parts by mass or less, after the film is formed, precipitation of excess (E) component as foreign matter tends to be suppressed.

(Other ingredients)
If necessary, the photosensitive resin composition includes a photopolymerizable compound (such as an oxetane compound) having at least one cationically polymerizable cyclic ether group in the molecule, a cationic polymerization initiator, malachite green, Victoria pure blue, and brilliant. Green, dyes such as methyl violet, photochromic agents such as tribromophenylsulfone, diphenylamine, benzylamine, triphenylamine, diethylaniline, 2-chloroaniline, thermochromic inhibitors, plasticizers such as 4-toluenesulfonamide, Pigments, fillers, antifoaming agents, flame retardants, stabilizers, adhesion-imparting agents, leveling agents, peeling accelerators, antioxidants, fragrances, imaging agents, thermal crosslinking agents, and the like may be included. These are used alone or in combination of two or more. When the photosensitive resin composition contains other components, these contents may be 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). preferable.

[Solution of photosensitive resin composition]
The photosensitive resin composition of this embodiment may further contain at least one organic solvent in order to adjust the viscosity as necessary. Organic solvents include alcohol solvents such as methanol and ethanol; ketone solvents such as acetone and methyl ethyl ketone; glycol ether solvents such as methyl cellosolve, ethyl cellosolve, and propylene glycol monomethyl ether; aromatic hydrocarbon solvents such as toluene; N, N- And aprotic polar solvents such as dimethylformamide. These may be used alone or in combination of two or more. The content of the organic solvent contained in the photosensitive resin composition can be appropriately selected depending on the purpose and the like. For example, the photosensitive resin composition can be used as a solution having a solid content of about 30 to 60% by mass. Hereinafter, the photosensitive resin composition containing the organic solvent is also referred to as “coating liquid”.

  A photosensitive resin composition layer can be formed using the photosensitive resin composition by applying (for example, applying) the coating liquid onto the surface of a support, a metal plate, or the like described later and drying it. . It does not restrict | limit especially as a metal plate, According to the objective etc., it can select suitably. Examples of the metal plate include metal plates such as copper, copper-containing alloys, iron-containing alloys such as nickel, chromium, iron, and stainless steel. As a metal plate, Preferably, metal plates, such as copper, a copper containing alloy, and an iron containing alloy, are mentioned.

  The thickness of the photosensitive resin composition layer to be formed is not particularly limited and can be appropriately selected depending on the application. For example, the thickness after drying is preferably 1 to 100 μm. When the photosensitive resin composition layer is formed on the metal plate, the surface of the photosensitive resin composition layer opposite to the metal plate may be covered with a protective layer. Examples of the protective layer include polymer films such as polyethylene and polypropylene.

  The photosensitive resin composition can be applied to the formation of the photosensitive resin composition layer of the photosensitive element described later. That is, another embodiment of the present invention comprises (A) component: a structural unit derived from (meth) acrylic acid, a structural unit derived from benzyl (meth) acrylate, and a structure derived from hydroxyalkyl ester of (meth) acrylic acid. A binder polymer having a unit, (B) component: a photopolymerizable compound containing a bisphenol-type di (meth) acrylate having 1 to 4 structural units of ethyleneoxy group, and (C) component: a photopolymerization initiator. Is applied to a photosensitive element.

  Moreover, the photosensitive resin composition of this embodiment can be used for the formation method of the resist pattern mentioned later. That is, another embodiment of the present invention comprises (A) component: a structural unit derived from (meth) acrylic acid, a structural unit derived from benzyl (meth) acrylate, and a structure derived from hydroxyalkyl ester of (meth) acrylic acid. A binder polymer having a unit, (B) component: a photopolymerizable compound containing a bisphenol-type di (meth) acrylate having 1 to 4 structural units of ethyleneoxy group, and (C) component: a photopolymerization initiator. Is applied to a method for forming a resist pattern.

<Photosensitive element>
The photosensitive element of this invention is equipped with the support body and the photosensitive resin composition layer formed from the said photosensitive resin composition provided on this support body. The photosensitive resin composition layer may be a coating film. The coating film as used in the present specification is that in which the photosensitive resin composition is in an uncured state. The photosensitive element may have other layers, such as a protective layer, as needed.

  FIG. 1 shows an embodiment of a photosensitive element. In the photosensitive element 1 shown in FIG. 1, the support body 2, the photosensitive resin composition layer 3 formed from the photosensitive resin composition, and the protective layer 4 are laminated | stacked in this order. The photosensitive element 1 can be obtained as follows, for example. A coating liquid (that is, a photosensitive resin composition containing an organic solvent) is applied on the support 2 to form a coating layer, which is dried to form the photosensitive resin composition layer 3. Next, the surface of the photosensitive resin composition layer 3 opposite to the support 2 is covered with a protective layer 4, thereby supporting the support 2 and the photosensitive resin composition layer 3 formed on the support 2. And the photosensitive element 1 of this embodiment provided with the protective layer 4 laminated | stacked on this photosensitive resin composition layer 3 is obtained. The photosensitive element 1 does not necessarily have to include the protective layer 4.

  As the support, a polymer film having heat resistance and solvent resistance such as polyester such as polyethylene terephthalate, polyolefin such as polypropylene and polyethylene can be used.

  The thickness of the support (polymer film) is preferably 1 to 100 μm, more preferably 5 to 50 μm, and still more preferably 5 to 30 μm. It can suppress that a support body is torn when peeling a support body because the thickness of a support body is 1 micrometer or more. Moreover, the fall of the resolution is suppressed because it is 100 micrometers or less.

  As a protective layer, the thing with the adhesive force with respect to the photosensitive resin composition layer smaller than the adhesive force with respect to the photosensitive resin composition layer of a support body is preferable. A low fisheye film is preferred. Here, “fish eye” means that when a material is heat-melted, kneaded, extruded, biaxially stretched, casting method, etc., foreign materials, undissolved materials, oxidatively deteriorated materials, etc. are present in the film. It means what was taken in. That is, the “low fish eye” means that there are few foreign matters in the film.

  Specifically, a polymer film having heat resistance and solvent resistance such as polyester such as polyethylene terephthalate, polyolefin such as polypropylene and polyethylene can be used as the protective layer. Examples of commercially available products include polypropylene films such as Alfan MA-410 and E-200 manufactured by Oji Paper Co., Ltd., Shin-Etsu Film Co., Ltd., and PS series polyethylene terephthalate films such as PS-25 manufactured by Teijin Limited. The protective layer 4 may be the same as the support 2.

  The thickness of the protective layer 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. When the thickness of the protective layer is 1 μm or more, the protective layer can be prevented from being broken when the photosensitive resin composition layer and the support are laminated on the substrate while peeling off the protective layer. When it is 100 μm or less, it is excellent in handleability and inexpensiveness.

  Specifically, the photosensitive element of this embodiment can be manufactured as follows, for example. (A) component: binder polymer, (B) component: photopolymerizable compound, and (C) a step of preparing a coating solution in which a photopolymerization initiator is dissolved in an organic solvent, and applying the coating solution on a support ( For example, it can be manufactured by a manufacturing method including a step of forming a coating layer by coating and a step of drying the coating layer to form a photosensitive resin composition layer.

  Application of the solution of the photosensitive resin composition onto the support can be performed by a known method such as roll coating, comma coating, gravure coating, air knife coating, die coating, or bar coating.

  The drying of the coating layer is not particularly limited as long as at least a part of the organic solvent can be removed from the coating layer. For example, it is preferable to dry the coating layer at 70 to 150 ° C. for 5 to 30 minutes. After drying, the amount of the remaining organic solvent in the photosensitive resin composition layer is preferably 2% by mass or less from the viewpoint of preventing diffusion of the organic solvent in the subsequent step.

  The thickness of the photosensitive resin composition layer in the photosensitive element can be appropriately selected depending on the application. The thickness after drying is preferably 1 to 100 μm, more preferably 1 to 50 μm, and still more preferably 5 to 40 μm. Industrial coating becomes easy because the thickness of the photosensitive resin composition layer is 1 μm or more. When it is 100 μm or less, adhesion and resolution tend to be sufficiently obtained.

  The transmittance of the photosensitive resin composition layer with respect to ultraviolet rays is preferably 5 to 75%, more preferably 10 to 65%, and more preferably 15 to 55% with respect to ultraviolet rays in the wavelength range of 350 to 430 nm. More preferably it is. When the transmittance is 5% or more, sufficient adhesion tends to be obtained. If it is 75% or less, sufficient resolution tends to be easily obtained. The transmittance can be measured with a UV spectrometer. An example of the UV spectrometer is a 228A type W beam spectrophotometer manufactured by Hitachi, Ltd.

  The photosensitive element may further include an intermediate layer such as a cushion layer, an adhesive layer, a light absorption layer, and a gas barrier layer. As these intermediate layers, for example, the intermediate layers described in JP-A-2006-098982 can also be applied in the present invention.

  The form of the obtained photosensitive element is not particularly limited. For example, it may be in the form of a sheet, or may be in the form of a roll wound around a core. When it winds up in roll shape, it is preferable to wind up so that a support body may become an outer side. 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). From the viewpoint of end face protection, it is preferable to install an end face separator on the end face of the roll-shaped photosensitive element roll thus obtained, and it is preferable to install a moisture-proof end face separator from the standpoint of edge fusion resistance. As a packaging method, it is preferable to wrap and package in a black sheet with low moisture permeability.

  The photosensitive element of this embodiment can be used suitably for the formation method of the resist pattern mentioned later, for example.

<Method for forming resist pattern>
A resist pattern can be formed using the photosensitive resin composition. The resist pattern forming method of this embodiment includes (i) a photosensitive layer forming step of forming a photosensitive resin composition layer on the substrate using the photosensitive resin composition, and (ii) the photosensitive resin composition. An exposure step of irradiating at least a part of the physical layer with actinic rays and photocuring the region to form a cured product region; and (iii) other than the cured product region of the photosensitive resin composition layer. And a developing step of removing a region from the substrate and forming a resist pattern as the cured product region on the substrate. The method for forming the resist pattern may further include other steps as necessary, and the photosensitive resin composition layer in the photosensitive layer forming step may be a coating film.

(I) Photosensitive layer formation process First, the photosensitive resin composition layer is formed on a board | substrate using the said photosensitive resin composition. As the substrate, a substrate (circuit forming substrate) including an insulating layer and a conductor layer formed on the insulating layer can be used.

  For example, when the photosensitive element has the protective layer 4, the photosensitive resin composition layer is formed on the substrate after the protective layer is removed and then the photosensitive resin composition layer of the photosensitive element. This is performed by pressure bonding to the substrate while heating. Thereby, the laminated body by which a board | substrate, the photosensitive resin composition layer, and a support body are laminated | stacked in this order is obtained.

This photosensitive layer forming step is preferably performed under reduced pressure from the viewpoint of adhesion and followability. Heating the photosensitive resin composition layer and at least one of the substrates during bonding is preferably carried out at a temperature of 70 to 130 ° C., about ^{0.1~1.0MPa (1kgf / cm 2 ~10kgf /} cm 2 of about It is preferable to perform pressure bonding with a pressure of). These conditions are not particularly limited, and are appropriately selected as necessary. Note that if the photosensitive resin composition layer is heated to 70 to 130 ° C., it is not necessary to pre-heat the substrate in advance. Adhesion and follow-up can be further improved by pre-heat treatment of the circuit forming substrate.

(Ii) Exposure step In the exposure step, the exposed portion irradiated with actinic rays is irradiated with actinic rays by irradiating at least a part of the photosensitive resin composition layer formed on the substrate as described above. It is photocured to form a latent image. Under the present circumstances, when the support body which exists on the photosensitive resin composition layer is transparent with respect to actinic light, actinic light can be irradiated through a support body. On the other hand, when the support is light-shielding against actinic rays, the photosensitive resin composition layer is irradiated with actinic rays after the support is removed.

  Examples of the exposure method include a method of irradiating an actinic ray in an image form through a negative or positive mask pattern called an artwork (mask exposure method). Alternatively, a method of irradiating actinic rays in an image form by a direct drawing exposure method such as an LDI (Laser Direct Imaging) exposure method or a DLP (Digital Light Processing) exposure method may be employed.

  The light source for actinic rays is not particularly limited, and a known light source can be used. For example, carbon arc lamp, mercury vapor arc lamp, high pressure mercury lamp, xenon lamp, gas laser such as argon laser, solid-state laser such as YAG laser, ultraviolet light such as semiconductor laser and blue-violet laser such as gallium nitride, etc. What to do is used.

  The wavelength of the actinic ray (exposure wavelength) is preferably in the range of 340 to 430 nm, and more preferably in the range of 350 to 420 nm, from the viewpoint of obtaining the effects of the present invention more reliably.

(Iii) Development Step In the development step, the uncured portion of the photosensitive resin composition layer is removed from the circuit forming substrate by a development process, whereby the photosensitive resin composition layer is a photocured cured product. A pattern is formed on the substrate. When the support is present on the photosensitive resin composition layer, the support is removed, and then the unexposed portion is removed (development). Development processing includes wet development and dry development, and wet development is widely used.

  In the case of wet development, development is performed by a known development method using a developer corresponding to the photosensitive resin composition. Examples of the developing method include a method using a dipping method, a paddle method, a spray method, brushing, slapping, scrubbing, rocking immersion, and the like. From the viewpoint of improving resolution, a high pressure spray method is preferable. You may develop by combining these 2 or more types of methods.

  A developing solution is suitably selected according to the structure of the photosensitive resin composition. Examples of the developer include an alkaline aqueous solution and an organic solvent developer.

  The alkaline aqueous solution is safe and stable when used as a developer, and has good operability. 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, sodium phosphate, and the like. Alkali metal phosphates; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate, borax (sodium tetraborate), sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2 -Amino-2-hydroxymethyl-1,3-propanediol, 1,3-diamino-2-propanol, morpholine and the like are used.

  Examples of the alkaline aqueous solution used for development include a dilute solution of 0.1 to 5% by mass of sodium carbonate, a dilute solution of 0.1 to 5% by mass of potassium carbonate, a dilute solution of 0.1 to 5% by mass of sodium hydroxide, A dilute solution of 1 to 5 mass% sodium tetraborate is preferred. The pH of the alkaline aqueous solution is preferably in the range of 9-11. Moreover, the temperature is adjusted according to the alkali 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 promoting development, and the like may be mixed.

  The alkaline aqueous solution may contain one or more organic solvents. Examples of the organic solvent to be used include 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 monobutyl ether, and the like. . These are used alone or in combination of two or more. When the organic solvent is included, the content of the organic solvent is preferably 2 to 90% by mass based on the alkaline aqueous solution. Moreover, the temperature can be adjusted according to alkali developability. A small amount of a surfactant, an antifoaming agent or the like may be mixed in the alkaline aqueous solution used for development.

  Examples of the organic solvent used in the organic solvent developer include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. In order to prevent flammability, it is preferable to add water in the range of 1 to 20% by mass to these organic solvents to obtain an organic solvent developer.

In the method of forming a resist pattern, after removing an unexposed portion, the resist pattern is further cured by heating at 60 to 250 ° C. or exposure with an energy amount of 0.2 to 10 J / cm ² as necessary. You may further include the process to do.

<Method for manufacturing printed wiring board>
The method for producing a printed wiring board according to the present invention includes a resist pattern formed on a conductive layer of a substrate (circuit forming substrate) including an insulating layer and a conductive layer formed on the insulating layer by the above-described resist pattern forming method. A step of forming a conductor pattern by etching or plating the substrate on which is formed. The manufacturing method of a printed wiring board may include other processes, such as a resist removal process, as needed. Etching or plating of the substrate is performed on the conductor layer of the substrate using the formed resist pattern as a mask.

  In the etching process, using the resist pattern (cured resist) formed on the substrate as a mask, the conductor layer of the circuit forming substrate not covered with the cured resist is removed by etching to form a conductor pattern. The etching method is appropriately selected according to the conductor layer to be removed. Examples of the etching solution include a cupric chloride aqueous solution, a ferric chloride aqueous solution, an alkali etching solution, and a hydrogen peroxide etching solution. Among these, it is preferable to use a ferric chloride aqueous solution because it has a good etch factor.

  On the other hand, in the plating process, copper, solder, or the like is plated on the conductor layer of the circuit forming substrate that is not covered with the cured resist, using the resist pattern (cured resist) formed on the substrate as a mask. After the plating treatment, the hardened resist is removed, and the conductor layer covered with the hardened resist is etched to form a conductor pattern. The method of plating treatment may be electrolytic plating treatment or electroless plating treatment. Plating treatment includes copper plating such as copper sulfate plating, copper pyrophosphate plating, solder plating such as high-throw solder plating, watt bath (nickel sulfate-nickel chloride) plating, nickel plating such as nickel sulfamate, hard gold plating, soft Examples thereof include gold plating such as gold plating.

  After the etching process and the plating process, the resist pattern on the substrate is removed (peeled). The removal of the resist pattern can be performed, for example, using a stronger alkaline aqueous solution than the alkaline aqueous solution used in the development step. As this strongly alkaline aqueous solution, 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. Among them, it is preferable to use a 1 to 10% by mass aqueous sodium hydroxide solution or a 1 to 10% by mass potassium hydroxide aqueous solution, and more preferably to use a 1 to 5% by mass sodium hydroxide aqueous solution or a 1 to 5% by mass potassium hydroxide aqueous solution. preferable. Examples of the method of applying a strong alkaline aqueous solution to the resist pattern include an immersion method and a spray method. These may be used alone or in combination of two or more.

  When the resist pattern is removed after the plating process, a desired printed wiring board can be manufactured by further removing the conductor layer covered with the cured resist by the etching process and forming the conductor pattern. The etching method is appropriately selected according to the conductor layer to be removed. For example, the above-described etching solution can be applied.

  The printed wiring board manufacturing method of the present invention can be applied not only to a single-layer printed wiring board but also to a multilayer printed wiring board, and also to a printed wiring board having a small-diameter through hole. .

The photosensitive resin composition of this embodiment can be used suitably for manufacture of a wiring board. That is, one of the preferred embodiments of the present invention includes (A) component: a structural unit derived from (meth) acrylic acid, a structural unit derived from benzyl (meth) acrylate, and a hydroxy having 1 to 12 carbon atoms. A binder polymer having a structural unit derived from a hydroxyalkyl ester of (meth) acrylic acid having an alkyl group, and (B) component: a bisphenol type di (meth) acrylate having 1 to 4 structural units of ethyleneoxy group This is an application of a photosensitive resin composition containing a photopolymerizable compound and a component (C): a photopolymerization initiator to the production of a printed wiring board.
A more preferred embodiment is the application of the photosensitive resin composition to the production of a high-density package substrate, and the application of the photosensitive resin composition to a semi-additive construction method. Below, an example of the manufacturing process of the wiring board by a semi-additive construction method is demonstrated, referring drawings.

  In FIG. 2A, a substrate (circuit forming substrate) in which the conductor layer 10 is formed on the insulating layer 15 is prepared. The conductor layer 10 is, for example, a metal copper layer. In FIG. 2B, the photosensitive resin composition layer 32 is formed on the conductor layer 10 of the substrate by the photosensitive layer forming step. In FIG.2 (c), the mask 20 is arrange | positioned on the photosensitive resin composition layer 32, the active light ray 50 is irradiated to the photosensitive resin composition layer 32 by the said exposure process, and the area | region where the mask 20 was arrange | positioned. A region other than the above is exposed to form a photocured portion in the photosensitive resin composition layer 32. In FIG.2 (d), the resist pattern 30 which is a photocuring part is formed on a board | substrate by removing area | regions other than a photocuring part in the photosensitive resin composition layer 32 from a board | substrate by a image development process. In FIG. 2E, a plating layer 42 is formed on the conductor layer 10 by plating using the resist pattern 30 that is a photocured portion as a mask. In FIG. 2F, after the resist pattern 30 which is a photocured portion is peeled off with a strong alkaline aqueous solution, a part of the plating layer 42 and the conductor layer 10 masked by the resist pattern 30 are removed by flash etching. The circuit pattern 40 is formed by removing. The conductor layer 10 and the plating layer 42 may be made of the same material or different materials. Although the method of forming the resist pattern 30 using the mask 20 has been described with reference to FIG. 2, the resist pattern 30 may be formed by direct drawing exposure without using the mask 20.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

(Example 1) (Preparation of solution of photosensitive resin composition)
By mixing the components (A) to (E) and dyes shown in Tables 2 and 3 with the compounding amounts (g units) shown in the same table together with 9 g of acetone, 5 g of toluene and 5 g of methanol, Examples 1 to 5 and Solutions of the photosensitive resin compositions of Comparative Examples 1 to 3 were prepared. The blending amount of the component (A) shown in Tables 2 and 3 is a mass part (solid content) of nonvolatile content. Details of each component shown in Tables 2 and 3 are as follows. “-” Means not blended.

(A) Binder polymer [synthesis of binder polymer (A-1)]
As a polymerizable monomer (monomer), 81 g of methacrylic acid, 9 g of 2-hydroxyethyl methacrylate, 141 g of styrene and 69 g of benzyl methacrylate (mass ratio 27/3/47/23), azobisisobutyronitrile The solution obtained by mixing 0 g was designated as “Solution a”.

  A solution obtained by dissolving 0.5 g of azobisisobutyronitrile in 100 g of a mixed solution (mass ratio 3: 2) of 60 g of methyl cellosolve and 40 g of toluene was designated as “Solution b”.

  A flask equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas introduction tube was charged with 300 g of a mixture of 180 g of methyl cellosolve and 120 g of toluene (mass ratio 3: 2), and nitrogen gas was introduced into the flask. The mixture was heated with stirring while being blown, and the temperature was raised to 80 ° C.

  The solution a was added dropwise to the mixed solution in the flask over a period of 4 hours at a constant dropping rate, and then stirred at 80 ° C. for 2 hours. Next, the solution b was dropped into the solution in the flask at a constant dropping rate over 10 minutes, and then the solution in the flask was stirred at 80 ° C. for 3 hours. Further, the solution in the flask was heated to 90 ° C. with stirring over 30 minutes, stirred at 90 ° C. for 2 hours, then cooled to room temperature to stop stirring, and the solution of the binder polymer (A-1) was removed. Obtained. In addition, the room temperature as used in the field of this invention means 25 degreeC.

  The binder polymer (A-1) had a nonvolatile content (solid content) of 42.6% by mass, a weight average molecular weight of 38000, an acid value of 176 mgKOH / g, and a dispersity of 1.8.

  The weight average molecular weight was measured by gel permeation chromatography (GPC) and derived by conversion using a standard polystyrene calibration curve. The GPC conditions are shown below.

GPC conditions Pump: Hitachi L-6000 type (manufactured by Hitachi, Ltd.)
Column: 3 in total, column specifications: Diameter 10.7 mm x 300 mm
Gelpack GL-R440
Gelpack GL-R450
Gelpack GL-R400M (above, manufactured by Hitachi Chemical Co., Ltd.)
Eluent: Tetrahydrofuran (THF)
Sample concentration: 120 mg of a binder polymer solution having a solid content of 41.2% by mass was sampled and dissolved in 5 mL of THF to prepare a sample.
Measurement temperature: 40 ° C
Injection volume: 200 μL
Pressure: 49Kgf / cm ² (4.8MPa)
Flow rate: 2.05 mL / min Detector: Hitachi L-3300 type RI (manufactured by Hitachi, Ltd.)

[Synthesis of Binder Polymer (A-2)]
A polymerizable monomer (monomer) of 72 g of methacrylic acid, 9 g of 2-hydroxyethyl methacrylate, 150 g of styrene and 69 g of benzyl methacrylate (mass ratio 24/3/50/23), azobisisobutyronitrile The solution obtained by mixing 5 g was referred to as “solution c”, and the binder polymer (A-1) was obtained in the same manner as the solution of the binder polymer (A-1) except that the solution c was used instead of the solution a. -2) was obtained.

[Synthesis of Binder Polymers (A-3) and (A-4)]
As the polymerizable monomer (monomer), the binder polymer (A-3) was obtained in the same manner as in the case of obtaining a solution of the binder polymer (A-1) except that the materials shown in Table 1 were used in the mass ratio shown in the same table. ) And (A-4) were obtained.

[Synthesis of Comparative Binder Polymer (A-5)]
A polymerizable monomer (monomer) of 81 g of methacrylic acid, 15 g of methyl methacrylate, 135 g of styrene and 69 g of benzyl methacrylate (mass ratio 27/5/45/23) and 1.0 g of azobisisobutyronitrile. The solution obtained by mixing was designated as “solution d”, and the solution of the binder polymer (A-1) was used in the same manner as in the case of obtaining the solution of the binder polymer (A-1) except that the solution d was used instead of the solution a. A solution of 5) was obtained.

[Synthesis of Comparative Binder Polymer (A-6)]
A solution obtained by mixing 72 g of methacrylic acid as a polymerizable monomer (monomer), 150 g of styrene and 78 g of benzyl methacrylate (mass ratio 24/50/26) and 1.5 g of azobisisobutyronitrile. A solution of a comparative binder polymer (A-6) was obtained in the same manner as that for obtaining a solution of the binder polymer (A-1) except that the solution e was used instead of the solution a. .

  About the binder polymers (A-1) to (A-4) and the comparative binder polymers (A-5) and (A-6), the mass ratio (%), the acid value and the weight of the polymerizable monomer (monomer). The average molecular weight and degree of dispersion are shown in Table 1.

(B) Photopolymerizable compound FA-324M: 2,2-bis (4- (methacryloxydiethoxy) phenyl) propane (manufactured by Hitachi Chemical Co., Ltd., “FA-324M”)
BPE-100: 2,2-bis (4- (methacryloxyethoxy) phenyl) propane (ethylene oxide average 2.6 mol adduct) (manufactured by Shin-Nakamura Chemical Co., Ltd., “BPE-100”)
FA-321M: 2,2-bis (4- (methacryloxyethoxy) phenyl) propane (ethylene oxide average 10 mol adduct) (manufactured by Hitachi Chemical Co., Ltd., “FA-321M”)
FA-3200MY: 2,2-bis (4- (methacryloxyethoxypropoxy) phenyl) propane (ethylene oxide average 12 mol and propylene oxide average 4 mol adduct) (manufactured by Hitachi Chemical Co., Ltd., “FA-3200MY”)
FA-023M: (EO) (PO) (EO) modified polypropylene glycol # 700 dimethacrylate (manufactured by Hitachi Chemical Co., Ltd., “FA-023M”, comparative photopolymerizable compound)

(C) Photopolymerization initiator B-CIM: 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbisimidazole [2- (2-chlorophenyl) -4,5 -Diphenylimidazole dimer] (Hampford, “B-CIM”)

(D) Sensitizing dye PYR-1: 1-phenyl-3- (4-methoxystyryl) -5- (4-methoxyphenyl) pyrazoline (manufactured by Nippon Chemical Industry Co., Ltd., “PYR-1”)

(E) Hydrogen donor LCV: Leuco Crystal Violet (Yamada Chemical Industries, Ltd., “LCV”)

Dye ・ MKG: Malachite Green (Osaka Organic Chemical Industry Co., Ltd., “MKG”)

<Production of photosensitive element>
The solution of the photosensitive resin composition obtained above was uniformly coated on a polyethylene terephthalate film (Toray Industries, Inc., “FB-40”) (support) having a thickness of 16 μm, and 70 ° C. and 110 ° C. The photosensitive resin composition layer having a dried film thickness of 25 μm was formed by sequentially drying with a hot air convection dryer. A polypropylene film (“E-200K”, manufactured by Oji Paper Co., Ltd.) (protective layer) is laminated on the photosensitive resin composition layer, and a support, a photosensitive resin composition layer, and a protective layer are sequentially laminated. The obtained photosensitive element was obtained.

<Production of laminated substrate>
A copper-clad laminate (manufactured by Hitachi Chemical Co., Ltd., “MCL-E-679F”) (hereinafter referred to as “substrate”) having a glass epoxy material and copper foil (thickness: 16 μm) formed on both surfaces thereof. After heating to 80 ° C., a photosensitive resin composition layer was formed on each copper surface of the substrate using the photosensitive elements according to Examples 1 to 5 and Comparative Examples 1 to 3 (laminate) )did. Lamination is performed under conditions of a temperature of 110 ° C. and a lamination pressure of 4 kgf / cm ² (0.4 MPa) so that the photosensitive resin composition layer of each photosensitive element is in close contact with the copper surface of the substrate while removing the protective layer. Went under. Thus, the laminated substrate by which the photosensitive resin composition layer and the support body were laminated | stacked on the copper surface of the board | substrate was obtained.

The obtained laminated substrate was allowed to cool to 23 ° C. Next, a 41-step tablet having a density region of 0.00 to 2.00, a density step of 0.05, a tablet size of 20 mm × 187 mm, and a size of each step of 3 mm × 12 mm on the support of the laminated substrate. A photo tool having Photo tool and support with an energy amount (exposure amount) of 100 mJ / cm ² using a direct drawing exposure machine (“DE-1UH” manufactured by Hitachi Via Mechanics Co., Ltd.) using a blue-violet laser diode with a wavelength of 405 nm as a light source The photosensitive resin composition layer was exposed through the body. For measurement of illuminance, an ultraviolet illuminance meter (Ushio Electric Co., Ltd., “UIT-150”) to which a 405 nm probe was applied was used.

<Evaluation of sensitivity>
After the exposure, the support was peeled from the laminated substrate to expose the photosensitive resin composition layer, and developed by spraying a 1% by mass aqueous sodium carbonate solution at 30 ° C. for 60 seconds to remove unexposed portions. Thus, the resist pattern which is the hardened | cured material of the photosensitive resin composition was formed on the copper surface of a board | substrate. The sensitivity of the photosensitive resin composition was evaluated by measuring the number of remaining steps (step number) of the step tablet obtained as a resist pattern (cured film). The sensitivity is indicated by the number of step steps, and the higher the step number, the better the sensitivity. The results are shown in Tables 4 and 5.

<Evaluation of resolution and adhesion>
Tables 4 and 5 show the drawing patterns having a line width (L) / space width (S) (hereinafter referred to as “L / S”) of 3/3 to 30/30 (unit: μm). The photosensitive resin composition layer of the laminated substrate was exposed (drawn) with an energy amount corresponding to the number of remaining steps of the 41-step tablet obtained by sensitivity evaluation. After the exposure, the same development processing as in the sensitivity evaluation was performed.

  After development, the space portion (unexposed portion) is removed cleanly, and the line portion (exposed portion) is the minimum of the line width / space width values in the resist pattern formed without causing meandering, chipping, or other defects. The resolution and adhesion were evaluated based on the values. A smaller value means better resolution and adhesion. In addition, the obtained resist pattern was confirmed to be defective by magnifying and observing at a magnification of 1000 times using a microscope. The results are shown in Tables 4 and 5.

<Evaluation of flexibility>
The flexibility of the resist pattern was evaluated as follows. An FPC (Flexible Printed Circuit) substrate (manufactured by Nikkan Kogyo Co., Ltd., “F-30VC1”, substrate thickness: 25 μm, copper thickness: 18 μm) was used. After heating the FPC board to 80 ° C., the photosensitive element according to Examples 1 to 5 and Comparative Examples 1 to 3 is used to laminate on the copper surface on the FPC board, thereby exposing the FPC board on the FPC board. A functional resin composition layer was formed. Lamination is performed by peeling the protective layer so that the photosensitive resin composition layer of each photosensitive element faces the FPC substrate side, heat roll temperature 110 ° C., laminating speed 1.5 m / min, laminating pressure 4 kgf / cm. ² (0.4 MPa). The FPC substrate on which the photosensitive resin composition layer and the support thus obtained were laminated was used as a test piece for evaluating flexibility. For the test piece, a direct drawing exposure machine (manufactured by Hitachi Via Mechanics Co., Ltd., “DE-1UH”) using a 405 nm blue-violet laser diode as a light source was used, and the sensitivity shown in Tables 4 and 5 was used. The entire surface was exposed with an energy amount corresponding to the number of remaining steps after development of the 41-step tablet obtained by the evaluation, and the photosensitive resin composition layer was photocured. Next, after the support was peeled off, development processing was performed in the same manner as the sensitivity evaluation described above to obtain a flexibility evaluation substrate in which a cured resist was laminated on one surface of the FPC substrate.

  The bendability was evaluated by a mandrel test, and the substrate for bendability evaluation was cut into a strip shape having a width of 2 cm and a length of 10 cm, and was rubbed back and forth 5 times at 180 ° with a cylindrical rod. Thereafter, the minimum diameter (mm) of the cylinder that does not peel off between the FPC substrate and the cured resist was obtained and used as an index for evaluating flexibility. In addition, the diameter of the cylinder was evaluated with 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, and 20 (unit: mm). The smaller the diameter of the cylinder, the better the flexibility. The results are shown in Tables 4 and 5.

  As is clear from Tables 4 and 5, Comparative Examples 1 and 2 that do not use the component (A) are inferior in flexibility, and Comparative Example 3 that does not use the component (B) is inferior in resolution and adhesion. On the other hand, a structural unit derived from (A) component (meth) acrylic acid, a structural unit derived from benzyl (meth) acrylate, and a hydroxy (meth) acrylate having a C1-C12 hydroxyalkyl group It was formed from a photosensitive resin composition containing a binder polymer having a structural unit derived from an alkyl ester and a bisphenol-type di (meth) acrylate having an ethyleneoxy group having 1 to 4 structural units as component (B). The resist pattern was excellent in all of resolution, adhesion and flexibility.

DESCRIPTION OF SYMBOLS 1 ... Photosensitive element, 2 ... Support body, 3 ... Photosensitive resin composition layer, 4 ... Protective layer, 10 ... Conductive layer, 15 ... Insulating layer, 20 ... Mask, 30 ... Resist pattern, 32 ... Photosensitive resin composition Physical layer, 40 ... circuit pattern, 42 ... plated layer, 50 ... active light

Claims (5)

  (A) Structural unit derived from (meth) acrylic acid, structural unit derived from benzyl (meth) acrylate, and structure derived from (meth) acrylic acid hydroxyalkyl ester having a hydroxyalkyl group having 1 to 12 carbon atoms A binder polymer having a unit, (B) a photopolymerizable compound containing a bisphenol-type di (meth) acrylate having 1 to 4 structural units of an ethyleneoxy group, and (C) a photopolymerization initiator. Photosensitive resin composition.   A photosensitive element provided with a support body and the photosensitive resin composition layer formed from the photosensitive resin composition of Claim 1 provided on the said support body.   A photosensitive layer forming step of forming a photosensitive resin composition layer on the substrate using the photosensitive resin composition according to claim 1, and an actinic ray in at least a part of the photosensitive resin composition layer. Irradiation, photocuring the region to form a cured product region, removing the region other than the cured product region of the photosensitive resin composition layer from the substrate, on the substrate A development step of forming a resist pattern which is a cured product region.   The resist pattern forming method according to claim 3, wherein the wavelength of the actinic ray is in a range of 340 to 430 nm.   A method for manufacturing a printed wiring board, comprising a step of etching or plating a substrate on which a resist pattern is formed by the method for forming a resist pattern according to claim 3 or 4.

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