WO2020243898A1 - Method for forming cured film - Google Patents

Method for forming cured film Download PDF

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Publication number
WO2020243898A1
WO2020243898A1 PCT/CN2019/089958 CN2019089958W WO2020243898A1 WO 2020243898 A1 WO2020243898 A1 WO 2020243898A1 CN 2019089958 W CN2019089958 W CN 2019089958W WO 2020243898 A1 WO2020243898 A1 WO 2020243898A1
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WIPO (PCT)
Prior art keywords
group
meth
resin
acrylate
photosensitive
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PCT/CN2019/089958
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French (fr)
Inventor
Akitoshi Tanimoto
Sadaaki Katou
Yasuharu Murakami
Xuesong Jiang
Xiao-dong MA
Original Assignee
Showa Denko Materials Co. Ltd
Shanghai Jiao Tong University
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Application filed by Showa Denko Materials Co. Ltd, Shanghai Jiao Tong University filed Critical Showa Denko Materials Co. Ltd
Priority to PCT/CN2019/089958 priority Critical patent/WO2020243898A1/en
Publication of WO2020243898A1 publication Critical patent/WO2020243898A1/en

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/004—Photosensitive materials
    • G03F7/027—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds
    • G03F7/032—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds with binders
    • G03F7/033—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds with binders the binders being polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/004—Photosensitive materials
    • G03F7/038—Macromolecular compounds which are rendered insoluble or differentially wettable
    • G03F7/0388—Macromolecular compounds which are rendered insoluble or differentially wettable with ethylenic or acetylenic bands in the side chains of the photopolymer

Definitions

  • the present disclosure relates to a method for forming a cured film.
  • An example of a method for manufacturing the printed wiring board adopted conventionally includes the method for manufacturing the multilayer printed wiring board by the buildup method which laminates and forms an interlayer insulation layer and a conductor circuit layer one by one (for example, refer to Patent Literature 1) .
  • a semi-additive method of forming circuits by plating has become mainstream in manufacturing of multilayer printed wiring boards in recent years.
  • a photosensitive resin composition is used as a material for forming an interlayer insulating layer.
  • the photosensitive resin composition generally contains a component having an acidic group such as a carboxy group.
  • a component having an acidic group such as a carboxy group.
  • multilayer printed wiring boards are required to be excellent in low dielectric characteristics (low dielectric constant and low dielectric loss tangent) .
  • the cured film formed using the photosensitive resin composition containing the component having a carboxy group requires improving low dielectric characteristics.
  • An object of the present invention is to provide a method for forming a cured film having excellent low dielectric characteristics.
  • the present invention relates to a method for forming a cured film, wherein the method includes a step of forming a photosensitive layer on a substrate using a photosensitive resin composition containing a carboxy group-containing resin, a photopolymerizable compound having an ethylenically unsaturated group, and a photopolymerization initiator; a step of exposing the photosensitive layer to a predetermined pattern; a step of obtaining a resin pattern by developing and removing the photosensitive layer in an unexposed area with an alkali aqueous solution; and a step of heat-treating the resin pattern at a temperature of 140°C or more to eliminate the carboxy group.
  • the present invention can provide a method for forming a cured film having excellent low dielectric characteristics.
  • Figure 1 is a schematic view showing one aspect of a manufacturing process of a multilayer printed wiring board according to the present embodiments.
  • step includes not only an independent step, but also a step that cannot be clearly distinguished from another step as long as the intended effect of the step is achieved.
  • the numerical range shown using “to” shows the range which includes the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
  • layer includes not only a structure of a shape formed on the entire surface but also a structure of a shape formed in part when it is observed as a plan view.
  • (Meth) acrylic acid means at least one of "acrylic acid” and “methacrylic acid” corresponding thereto. The same applies to other similar expressions such as (meth) acryloyl.
  • the amount of each component in the photosensitive resin composition means the total amount of the plurality of the substances present in the photosensitive resin composition.
  • the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in Examples.
  • the aspect which arbitrarily combines the matters described in this description is also included in this invention.
  • solids refers to non-volatile components excluding volatiles such as water and solvents contained in the photosensitive resin composition. That is, “solids” refers to components other than the solvent which remains without volatilization in drying of the photosensitive resin composition described below, and also includes liquid, millet jelly-like, and wax components at room temperature (25°C) .
  • the method for forming a cured film (resist pattern) includes a step of forming a photosensitive layer on a substrate using a photosensitive resin composition containing a carboxy group-containing resin, a photopolymerizable compound having an ethylenically unsaturated group, and a photopolymerization initiator; a step of exposing the photosensitive layer to a predetermined pattern; a step of obtaining a resin pattern by developing and removing the photosensitive layer in an unexposed area with an alkali aqueous solution; and a step of heat-treating the resin pattern at a temperature of 140°C or more to eliminate the carboxy group.
  • the heat treatment at 140°C or more eliminates at least a part of the carboxy group derived from the carboxy group-containing resin included in the resin pattern, and thereby improves low dielectric characteristics of the cured film after the heat treatment.
  • the method for forming the cured film according to the present embodiments is described in detail.
  • a substrate such as a copper-clad laminate board is provided, and a photosensitive layer is formed on the substrate.
  • the substrate may be coated with the photosensitive resin composition using methods such as a printing method, a spin coating method, a spraying method, a jet dispensing method, an inkjet method, a roll coating method, a curtain coating method, and an electrostatic coating method.
  • the photosensitive layer can be provided by drying a coating film at 60 to 110°C, the coating film being formed by coating the substrate with the photosensitive resin composition.
  • the photosensitive resin composition may be used in the form of a film (photosensitive film) described below.
  • the photosensitive layer may also be provided by laminating the photosensitive layer of the photosensitive film on the substrate using a laminator.
  • the lamination may be performed, for example, by preheating the photosensitive film and the substrate, as required, and then performed at a temperature of 70 to 130°C, a pressure of 0.1 to 1.0 MPa, and a reduced pressure of air pressure 20 mmHg (26.7 hPa) or less.
  • the type of the lamination may be batch or continuous by the roll.
  • the photosensitive layer is exposed to a predetermined pattern through a predetermined mask.
  • the exposure method is not particularly limited, and for example may adopt a method of imagewise irradiating actinic light through a negative or positive mask pattern referred to as artwork (mask exposure method) and may adopt a method of imagewise irradiating actinic light by direct drawing exposure method such as LDI (Laser Direct Imaging) exposure method or DLP (Digital Light Processing) exposure method.
  • LDI Laser Direct Imaging
  • DLP Digital Light Processing
  • a known light source can be used as a light source of actinic light.
  • the light source include a light source that effectively emits ultraviolet light or visible light such as gas laser such as carbon arc lamp, mercury vapor arc lamp, high pressure mercury lamp, xenon lamp, and argon laser; solid laser such as YAG laser; and semiconductor laser.
  • the exposure dose is appropriately selected depending on the light source to be used, the thickness of the photosensitive layer, and the like.
  • the exposure dose may be 10 to 1000 mJ/cm 2 or 15 to 500 J/m 2 .
  • the support film After exposure, when a support film is present on the photosensitive layer, the support film is removed and then the unexposed area is removed (developed) with an alkaline developer to obtain a resin pattern.
  • the development method include methods using a dip method, a paddle method, a spray method, brushing, slapping, scrubbing, swing immersion, or the like. From the viewpoint of improving resolution, a spray method is preferable, and a high pressure spray method is more preferable.
  • alkaline developer examples include an alkaline aqueous solution in which an alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, tetramethylammonium hydroxide or choline is dissolved in water to a concentration of about 1 to 10%by mass; and ammonia water.
  • an alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, tetramethylammonium hydroxide or choline is dissolved in water to a concentration of about 1 to 10%by mass; and ammonia water.
  • the resin pattern is heat-treated to obtain a cured film (resist pattern) .
  • Heat-treating the resin pattern eliminates at least a part of the carboxy group. Elimination of the carboxy group can enhance the low dielectric characteristics of the cured film.
  • the heat treatment is performed under the condition of a temperature or more at which the elimination of the carboxy group occurs.
  • the heating temperature 140 to 250°Cis preferable, 150 to 230°C is more preferable, and 160 to 200°C is still more preferable.
  • the heating time about 30 minutes to 10 hours is preferable, 1 hour to 5 hours is more preferable, and 1.5 hours to 3 hours is still more preferable.
  • the photosensitive resin composition according to the present embodiments contains (A) an alkali-soluble resin (hereinafter sometimes referred to as “component (A) " ) , and (B) a photopolymerizable compound having an ethylenically unsaturated group (hereinafter sometimes referred to as “component (B) " ) , and (C) a photopolymerization initiator (hereinafter sometimes referred to as “component (C) " ) .
  • component (A) an alkali-soluble resin
  • component (B) a photopolymerizable compound having an ethylenically unsaturated group
  • component (C) a photopolymerization initiator
  • the component (A) is a resin soluble in an alkali aqueous solution.
  • the alkali aqueous solution is an alkaline aqueous solution such as tetramethyl ammonium hydroxide (TMAH) aqueous solution, metal hydroxide aqueous solution, metal carbonate aqueous solution, and organic amine aqueous solution.
  • TMAH tetramethyl ammonium hydroxide
  • metal hydroxide aqueous solution metal carbonate aqueous solution
  • organic amine aqueous solution organic amine aqueous solution.
  • a substrate such as a silicon wafer is spin-coated with a varnish obtained by dissolving the component (A) in an arbitrary solvent to form a coating film having about 5 ⁇ m thickness.
  • This is immersed in any of TMAH aqueous solution, metal hydroxide aqueous solution, metal carbonate aqueous solution, or organic amine aqueous solution at 20 to 25°C.
  • TMAH aqueous solution metal hydroxide aqueous solution
  • metal carbonate aqueous solution metal carbonate aqueous solution
  • organic amine aqueous solution organic amine aqueous solution
  • the component (A) includes the carboxy group-containing resin.
  • the carboxy group-containing resin is not particularly limited as long as it has a structure in which the carboxy group is eliminated at a temperature of 140°C or more.
  • the carboxy group-containing resin may be composed of only one resin, or may be composed of two or more resins.
  • a resin having a group represented by the following formula (1) (hereinafter, sometimes referred to as “component (A1) " ) may be used.
  • the component (A1) Since the component (A1) has a group represented by formula (1) , it has excellent solubility in an alkali aqueous solution.
  • the component (A1) is heat-treated at 140°C or more, thereby eliminating at least a part of the carboxy group from the group represented by formula (1) to improve low dielectric characteristics after the heat treatment.
  • the group represented by formula (1) may be referred to as a ⁇ -ketocarboxy group.
  • the component (A1) may be a resin having a structural unit based on the carboxy group-containing compound having a (meth) acryloyl group and the group represented by formula (1) .
  • the carboxy group-containing compound may be a compound having a structure represented by the following formula (3) .
  • R 1 represents a hydrogen atom or a methyl group and L 1 represents an alkylene group having 1 to 10 carbon atoms.
  • L 1 is preferable to be an alkylene group having 1 to 6 carbon atoms, more preferable to be an alkylene group having 1 to 4 carbon atoms, and still more preferable to be an alkylene group having 2 or 3 carbon atoms.
  • the compound represented by formula (3) can be obtained, for example, by reacting a (meth) acryloyl compound having a hydroxyl group with malonic acid.
  • the (meth) acryloyl compound having a hydroxyl group include hydroxyalkyl (meth) acrylates such as hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyheptyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxynonyl (meth) acrylate, and hydroxydecyl (meth) acrylate.
  • the content of the carboxy group-containing compound may be 5%by mass or more, 8%by mass or more, 10%by mass or more, or 12%by mass or more, based on the total amount of the monomers constituting the carboxy group-containing resin. From the viewpoint of further improving the low dielectric characteristics, the content of the carboxy group-containing compound may be 90%by mass or less, 85%by mass or less, 80%by mass or less, or 75%by mass or less.
  • the above carboxy group-containing resin may further have a structural unit based on an aromatic vinyl compound.
  • aromatic vinyl compound include styrene, ⁇ -methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-methoxystyrene, m-methoxystyrene, and p-methoxystyrene.
  • the above carboxy group-containing resin according to the present embodiments may further have a structural unit based on a (meth) acrylate.
  • the (meth) acrylate may be a compound having an alkyl group or a hydroxyalkyl group.
  • Examples of the (meth) acrylate include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, and decyl (meth) acrylate; and hydroxyalkyl (meth) acrylates such as hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyheptyl (meth) acrylate, hydroxy
  • the component (A1) may be an epoxy resin derivative having the group represented by formula (1) .
  • the epoxy resin derivative may be, for example, a compound obtained by reacting malonic acid with an esterified product of an epoxy resin and an ethylenically unsaturated group-containing monocarboxylic acid.
  • Examples of the epoxy resin include a phenol novolac type epoxy resin, a bisphenol type epoxy resin, and a dicyclopentadiene type epoxy resin.
  • a resin having a group represented by the following formula (2) (hereinafter, sometimes referred to as “component (A2) " ) may be used.
  • X represents a group having a cycloalkane ring, a cycloalkene ring, or an aromatic ring.
  • the group represented by formula (2) may be at least one group selected from the group consisting of groups represented by the following formulas (2a) , (2b) , and (2c) .
  • the component (A2) may be an epoxy resin derivative having the group represented by formula (2) .
  • the weight average molecular weight (Mw) of the carboxy group-containing resin may be 1000 or more, 2000 or more, or 3000 or more. From the viewpoint of being suitably developable, Mw of the carboxy group-containing resin may be 30000 or less, 25000 or less, or 18000 or less. Mw can be measured, for example, by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.
  • GPC gel permeation chromatography
  • the component (A) may further include an alkali-soluble resin other than the components (A1) and (A2) .
  • the alkali-soluble resin may be a resin having a phenolic hydroxyl group.
  • the resin having a phenolic hydroxyl group include polyhydroxystyrene, hydroxystyrene-based resins such as copolymers including hydroxystyrene as a monomer unit, phenolic resins, polybenzoxazole precursors such as poly (hydroxyamide) , poly (hydroxyphenylene) ether, and polynaphthol.
  • the acid value of the component (A) may be 30 mg KOH/g or more, 40 mg KOH/g or more, or 50 mg KOH/g or more, and from the viewpoint of improving the adhesion (developer resistance) of the cured product of the photosensitive resin composition, it may be 250 mg KOH/g or less, 230 mg KOH/g or less, or 200 mg KOH/g or less.
  • the acid value of the component (A) can be adjusted by the content of a structural unit based on the carboxy group-containing compound.
  • the content of the component (A) may be 50 parts by mass or more, 60 parts by mass or more, or 70 parts by mass or more, per 100 parts by mass in total of the component (A) , the component (B) , and the component (C) . From the viewpoint of improving sensitivity and resolution, the content of the component (A) may be 95 parts by mass or less, 90 parts by mass or less, or 85 parts by mass or less.
  • the component (B) is a compound having a functional group having an ethylenically unsaturated bond such as a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenyl ethynyl group, a maleimide group, a nadimide group, and a (meth) acryloyl group as a functional group which exhibits photopolymerization.
  • the component (B) is not particularly limited as long as it is a compound having one or more ethylenically unsaturated groups.
  • a (meth) acryloyl group is preferable.
  • the component (B) may be used singly or in combination of two or more.
  • Examples of the photopolymerizable compound having one ethylenically unsaturated group include (meth) acrylic acids, alkyl (meth) acrylates, and phthalic acid-based (meth) acrylate compounds.
  • alkyl (meth) acrylate examples include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and hydroxylethyl (meth) acrylate.
  • the component (B) may include a phthalic acid-based compound.
  • the phthalic acid-based compound include ⁇ -chloro- ⁇ -hydroxypropyl- ⁇ '- (meth) acryloyloxyethyl-o-phthalate (aka: 3-chloro-2-hydroxypropyl-2- (meth) acryloyloxyethylphthalate) , ⁇ -hydroxyethyl- ⁇ '- (meth) acryloyloxyethyl-o-phthalate, and ⁇ -hydroxypropyl- ⁇ '- (meth) acryloyloxyethyl-o-phthalate.
  • Examples of the photopolymerizable compound having two ethylenically unsaturated groups include polyethylene glycol di(meth) acrylate, trimethylolpropane di (meth) acrylate, polypropylene glycol di (meth) acrylate, 2, 2-bis (4- (meth) acryloxypolyethoxypolypropoxyphenyl) propane, bisphenol A diglycidyl ether di (meth) acrylate, and alkylene oxide-modified bisphenol A di (meth) acrylate.
  • the component (B) may include an alkylene oxide-modified bisphenol A di (meth) acrylate.
  • alkylene oxide modified bisphenol A di (meth) acrylate examples include 2, 2-bis (4- ( (meth) acryloxypolyethoxy) phenyl) propane (2, 2-bis (4- ( (meth) acryloxypentaethoxy) phenyl) propane or the like) , 2, 2-bis (4- ( (meth) acryloxypolypropoxy) phenyl) propane, 2, 2-bis (4- ( (meth) acryloxypolybutoxy) phenyl) propane, and 2, 2-bis (4- ( (meth) acryloxypolyethoxypolypropoxy) phenyl) propane.
  • Examples of the photopolymerizable compound having 3 or more ethylenically unsaturated groups include (meth) acrylate having a skeleton derived from trimethylolpropane such as trimethylolpropane tri(meth) acrylate; (meth) acrylate having a skeleton derived from tetramethylolmethane such as tetramethylolmethane tri (meth) acrylate and tetramethylolmethane tetra (meth) acrylate; (meth) acrylate having a skeleton derived from pentaerythritol such as pentaerythritol tri(meth) acrylate and pentaerythritol tetra (meth) acrylate; (meth) acrylate having a skeleton derived from dipentaerythritol such as dipentaerythritol penta (meth) acrylate and dipentaeryth
  • (meth) acrylate compounds having a skeleton derived from dipentaerythritol are preferable and dipentaerythritol penta (meth) acrylate is more preferable.
  • the component (B) may include a photopolymerizable compound having an ethylenically unsaturated group and an acid-modified group.
  • the acidic group to be modified include a carboxy group, a sulfo group, and a phenolic hydroxyl group, and among them, the carboxy group is preferable.
  • Examples of the photopolymerizable compound having an ethylenically unsaturated group and an acidic group include styrene-maleic acid-based resin and epoxy derivative containing an acid-modified vinyl group.
  • the styrene-maleic acid-based resin is a hydroxyethyl (meth) acrylate modified product of a styrene-maleic anhydride copolymer.
  • the epoxy derivative containing an acid-modified vinyl group is a compound obtained by reacting a compound having epoxy resin modified with vinyl group-containing organic acid with saturated or unsaturated group-containing polybasic acid anhydride.
  • the epoxy resin is not particularly limited as long as it is a compound having two or more epoxy groups.
  • the epoxy resin include a glycidyl ether type epoxy resin, a glycidylamine type epoxy resin, and a glycidyl ester type epoxy resin. Among them, from the viewpoint of reliability in mounting semiconductor chips, a bisphenol-based novolac type epoxy resin is preferable and a bisphenol F novolac type epoxy resin is more preferable.
  • the vinyl group-containing organic acid is not particularly limited, and may be a vinyl group-containing monocarboxylic acid.
  • the vinyl group-containing monocarboxylic acid include acrylic acid derivatives such as acrylic acid, a dimer of acrylic acid, methacrylic acid, ⁇ -furfurylacrylic acid, ⁇ -styrylacrylic acid, cinnamic acid, crotonic acid, and ⁇ -cyanocinnamic acid; a half ester compound which is a reaction product of a hydroxyl group-containing acrylate and a dibasic acid anhydride; and a half ester compound which is a reaction product of a vinyl group-containing monoglycidyl ether or a vinyl group-containing monoglycidyl ester with a dibasic acid anhydride.
  • An acid-modified vinyl group-containing epoxy derivative may have a group represented by formula (1) or (2) .
  • Use of a carboxy group-containing resin as the component (B) can improve the alkali developability of the unexposed area of the photosensitive layer.
  • the component (C) is not particularly limited as long as it is a component capable of polymerizing the component (B) , and can be appropriately selected from commonly used photopolymerization initiators.
  • the component (C) can be used singly or in combination of two or more.
  • component (C) examples include benzoin compounds such as benzoin, benzoin methyl ether, and benzoin isopropyl ether; acetophenone compounds such as acetophenone, 2, 2-dimethoxy-2-phenylacetophenone, 2, 2-diethoxy-2-phenylacetophenone, 1, 1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone, and N, N-dimethylaminoacetophenone; anthraquinone compounds such as 2-methyl anthraquinone, 2-ethyl anthraquinone, 2-tert-butyl anthraquinone, 1-chloroanthraquinone, 2-amyl anthraquinone,
  • the content of the component (C) is not particularly limited. From the viewpoint of improving the sensitivity of the resin pattern, the content of the component (C) may be 0.1 parts by mass or more, 0.3 parts by mass or more, or 0.5 parts by mass or more, per 100 parts by mass in total of the total of the component (A) , the component (B) , and the component (C) . From the viewpoint of improving the heat resistance of the resist pattern, the content of the component (C) may be 3 parts by mass or less, 2 parts by mass or less, or 1 part by mass or less.
  • the photosensitive resin composition according to the present embodiments may contain a photoinitiation auxiliary as component (C') with the component (C) .
  • a photoinitiation auxiliary include tertiary amine compounds such as ethyl N, N-dimethylaminobenzoate, isoamyl N, N-dimethylaminobenzoate, pentyl-4-dimethylaminobenzoate, triethylamine, and triethanolamine.
  • the component (C') may be used singly or in combination of two or more.
  • the photosensitive resin composition according to the present embodiments may further contain an acid catalyst.
  • the elimination of the carboxy group can be promoted by the acid catalyst.
  • the resin having the group represented by formula (2) is used, particularly it is preferable to use the acid catalyst together.
  • Examples of the component (D) include a compound (photoacid generator) that generates an acid by light (by receiving light) and a compound (thermal acid generator) that generates an acid by heating.
  • the component (D) may be used singly or in combination of two or more.
  • Examples of the photoacid generator include an iodonium salt and a sulfonium salt.
  • the sulfonium salt include triarylsulfonium salts such as triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, and triphenylsulfonium hexafluoroantimonate.
  • Examples of the thermal acid generator include an onium salt.
  • onium salt examples include trimethylsulfonium methylsulfate, 2, 6-dimethylpyridinium p-toluenesulfonate, 2-chloro-1-methylpyridinium p-toluenesulfonate, and 2-fluoro-1-methylpyridinium p-toluenesulfonate.
  • the photosensitive resin composition according to the present embodiments in addition to the components (A) to (D) , may further contain solvent, epoxy resin, elastomer, thermal polymerization initiator, inorganic filler, polymerization inhibitor, thickener, antifoaming agent, silane coupling agent, flame retardant, and the like.
  • the photosensitive resin composition according to the present embodiments contains a solvent and thereby can be easily applied on a substrate to form a coating film having uniform thickness.
  • the solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, propylene glycol monoethyl ether acetate, butyl cellosolve acetate, and carbitol acetate; aliphatic hydrocarbons such as octane and decane;
  • the epoxy resin examples include a bisphenol type epoxy resin, a bisphenol novolac type epoxy resin, a phenol aralkyl type epoxy resin, a biphenyl aralkyl type epoxy resin, a stilbene type epoxy resin, a dicyclopentadiene type epoxy resin, a naphthalene type epoxy resin, a biphenyl type epoxy resin, a biphenylaralkyl type epoxy resin, a xylylene type epoxy resin, a dihydroanthracene type epoxy resin, a dicyclopentadiene type epoxy resin, an alicyclic epoxy resin, an aliphatic chain epoxy resin, and a rubber modified epoxy resin.
  • the elastomer examples include a styrene-based elastomer, an olefin-based elastomer, a polyester-based elastomer, a urethane-based elastomer, a polyamide-based elastomer, an acrylic elastomer, and a silicone-based elastomer.
  • an organic peroxide or an azo compound may be used as the thermal polymerization initiator.
  • the organic peroxide include hydroperoxides such as diisopropylbenzene hydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide; dialkylperoxides such as ⁇ , ⁇ -bis (t-butylperoxy-m-isopropyl) benzene, dicumyl peroxide, 2, 5-dimethyl-2, 5-bis (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, and 2, 5-dimethyl-2, 5-bis (t-butylperoxy) hexyne-3, t-butylperoxy-2-ethylhexanoate; ketone peroxides; peroxyketals such as n-butyl 4, 4-di- (t-butylperoxy) valerate; diacyl per
  • examples of the inorganic filler include silica, alumina, titania, tantalum oxide, zirconia, silicon nitride, barium titanate, barium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, lead titanate, lead zirconate titanate, lead lanthanum zirconate titanate, gallium oxide, spinel, mullite, cordierite, talc, aluminum titanate, yttria-containing zirconia, barium silicate, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, zinc oxide, magnesium titanate, hydrotalcite, mica, calcined kaolin, and carbon.
  • a coloring agent which develops a desired color can be appropriately selected and used, and examples of the pigment include phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black.
  • Examples of the polymerization inhibitor include hydroquinone, methyl hydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol.
  • Examples of the thickener include benton and montmorillonite.
  • Examples of the antifoaming agent include silicone-based antifoaming agent, fluorine-based antifoaming agent, and vinyl resin-based antifoaming agent.
  • Examples of the flame retardant include a brominated epoxy compound, an acid-modified brominated epoxy compound, an antimony compound, a phosphate compound, an aromatic condensed phosphate, and a halogen-containing condensed phosphate.
  • the photosensitive resin composition according to the present embodiments can be prepared by mixing each component with a roll mill, a bead mill, or the like.
  • the photosensitive resin composition according to the present embodiments is excellent in alkali developability and can form a cured film excellent in low dielectric characteristics.
  • the photosensitive resin composition can be suitably used for forming a resist pattern, and can be particularly suitably used for the method for manufacturing a multilayer printed wiring board described below.
  • the photosensitive film according to the present embodiments includes a support film and the photosensitive layer formed from the above-described photosensitive resin composition.
  • the photosensitive film includes a support film and a photosensitive layer formed on the support film.
  • the photosensitive film can be prepared by applying the photosensitive resin composition according to the present embodiments on a support film with known coating devices such as a bar coater, a reverse roll coater, a gravure roll coater, a comma coater, a curtain coater, a kiss coater, and a die coater and then by drying a coating film to form a photosensitive layer.
  • known coating devices such as a bar coater, a reverse roll coater, a gravure roll coater, a comma coater, a curtain coater, a kiss coater, and a die coater and then by drying a coating film to form a photosensitive layer.
  • the support film examples include polyester films such as polyethylene terephthalate and polybutylene terephthalate and polyolefin films such as polypropylene and polyethylene.
  • the thickness of the support film may be, for example, 5 to 100 ⁇ m, 5 to 60 ⁇ m, or 15 to 45 ⁇ m.
  • the thickness of the photosensitive layer is not particularly limited, but may be 1 to 100 ⁇ m, 1 to 50 ⁇ m, or 5 to 40 ⁇ m from the viewpoint of thinning the multilayer printed wiring board.
  • the drying of the coating film can be performed using hot air drying, or drying using far infrared radiation or near infrared radiation.
  • the drying temperature may be, for example, 60 to 130°C, 70 to 120°C, or 80 to 110°C.
  • the drying time may be, for example, 1 to 60 minutes, 2 to 30 minutes, or 5 to 20 minutes.
  • the photosensitive film according to the present embodiments can also laminate a protective film on the surface opposite to the surface in contact with the support film of the photosensitive layer.
  • a protective film for example, polyolefin films such as polyethylene and polypropylene may be used.
  • the protective film may be the same film as the support film.
  • the cured product of the photosensitive resin composition of the present embodiments can be suitably used, for example, as a surface protective film (overcoat film) and/or an interlayer insulating film (passivation film) of a semiconductor element, or a solder resist and/or an interlayer insulating layer in a multilayer printed wiring board.
  • Figure 1 is a view showing a method for manufacturing a multilayer printed wiring board including a cured product of the photosensitive resin composition according to the present embodiments as a solder resist and/or an interlayer insulating film.
  • the multilayer printed wiring board 100A shown in (f) of Figure 1 has a wiring pattern on the surface and inside.
  • the multilayer printed wiring board 100A can be obtained by appropriately forming a wiring pattern by an etching method or a semi-additive method, in addition to laminating a copper-clad laminate, an interlayer insulating film, a metal foil, and the like.
  • a method for manufacturing the multilayer printed wiring board 100A will be briefly described based on Figure 1.
  • the interlayer insulating film 103 is formed on both surfaces of the copper-clad laminate 101 having a wiring pattern 102 on the surface (refer to Figure 1 (a) ) .
  • the interlayer insulating film 103 may be formed by printing the above-described photosensitive resin composition using a screen printer or a roll coater, and can also be formed by providing the above-described photosensitive film in advance and bonding the photosensitive layer of the photosensitive film to the surface of the printed wiring board using a laminator.
  • the region other than the portion required to be electrically connected to the outside in the interlayer insulating film 103 is exposed and developed to form the opening 104 (refer to Figure 1 (b) ) .
  • Smear (residue) around the opening 104 is removed by desmear treatment.
  • the size (diameter) of the opening 104 is not particularly limited, and can be arbitrarily selected, for example, in the range of 15 to 300 ⁇ m.
  • the seed layer 105 is formed on the interlayer insulating film 103 and the opening 104 by the electroless plating method (refer to Figure 1 (c) ) .
  • the thickness of the seed layer 105 may be about 0.1 to 2.0 ⁇ m.
  • a photosensitive layer formed from the above-described photosensitive resin composition is formed on the seed layer 105, and predetermined portions are exposed and developed to form the resin pattern 106 (refer to Figure 1 (d) ) .
  • an operation of removing the development residue of the photosensitive layer may be performed using plasma or the like.
  • the wiring pattern 107 is formed by the electro-plating method and the resin pattern 106 is removed by a peeling solution, and then the seed layer 105 between the wirings is removed by etching (refer to Figure 1 (e) ) .
  • the multilayer printed wiring board 100A can be produced by repeatedly performing the above operation and forming the solder resist 108 including the cured product of the above-described photosensitive resin composition on the outermost surface (refer to Figure 1 (f) ) .
  • the semiconductor element is mounted at the corresponding position, and electrical connection can be secured.
  • a semiconductor package mounting a semiconductor element can be produced in the printed wiring board according to the present embodiments.
  • the semiconductor package can be manufactured by mounting semiconductor elements such as a semiconductor chip and memory at a predetermined position of the above-described printed wiring board and sealing the semiconductor elements with a sealing resin or the like.
  • the solution was poured into 100 mL of water, and the separated oily component was collected. 15 mL of chloroform was added to the aqueous solution from which the oily component was removed, and liquid separation operation was performed three times to collect an organic layer. The oily component and the organic layer were mixed and washed with a saturated saline solution to obtain a chloroform solution of the product. 50 mL of a 0.16%by mass sodium carbonate aqueous solution was added to the chloroform solution of the product to collect the aqueous layer. The collected aqueous layer was washed with chloroform to obtain an aqueous solution of the product.
  • polymer A 25 g of the compound a, 75 g of 1, 4-dioxane, and 0.5 g of 2, 2'-azodiisobutyronitrile (AIBN) were poured into 100 mL four-necked flask equipped with a stirrer, a nitrogen introduction pipe, a reflux condenser, a dropping funnel, and a thermometer, and were stirred at 75°C for 6 hours under a nitrogen atmosphere and then cooled to room temperature to obtain a solution of a carboxy group-containing resin (hereinafter referred to as "polymer A" ) .
  • polymer A a carboxy group-containing resin
  • polymer C A solution of a carboxy group-containing resin (hereinafter referred to as "polymer C” ) was obtained in the same manner as in Synthesis Example 2, except that a mixture of 36 g of styrene, 84 g of the compound a, and 1.01 g of AIBN was dropped.
  • a solution of the polymer B and a solution of the polymer C were mixed at a ratio of 80 parts by mass of the polymer B and 20 parts by mass of the polymer C to obtain a solution of polymer E.
  • a solution of the polymer B and a solution of the polymer C were mixed at a ratio of 54 parts by mass of the polymer B and 46 parts by mass of the polymer C to obtain a solution of polymer F.
  • polymer D A solution of a carboxy group-containing resin (hereinafter referred to as "polymer D” ) was obtained in the same manner as in Synthesis Example 2, except that a mixture of 142 g of styrene, 25.2 g of methacrylic acid, and 1.41 g of AIBN was dropped.
  • the acid value of the polymers A to F was calculated from the structure of monomer constituting the polymer and copolymerization ratio.
  • a solution of the polymers A to F was applied on a substrate using an applicator and dried at 80°C for 10 minutes to form a resin film having a thickness of 10 to 20 ⁇ m.
  • the resin film was developed at 30°C for 50 seconds, 80 seconds, and 120 seconds, respectively, using 1.0%by mass of a sodium carbonate aqueous solution.
  • the average dissolution rate of the resin film was calculated from the thickness of the resin film after development. The results are shown in Table 1.
  • Dissolution rate ( ⁇ m/s) [thickness before development ( ⁇ m) -thickness after development ( ⁇ m) ] /development time (s)
  • a resin film was formed by using a solution of the polymer A and drying at 80°C for 10 minutes and then the resin film was heat-treated at 170°C for 2 hours.
  • the infrared absorption spectra of the resin film before and after the heat treatment were measured and the elimination of a carboxy group after the heat treatment was determined by the spectral change derived from the carboxy group.
  • a PET film was coated with a solution of the polymer A using an applicator and dried at 80°C for 10 minutes to form a resin film having a thickness of 100 to 150 ⁇ m.
  • the resin film was heat-treated at 170°C for 2 hours.
  • the dielectric loss tangent (Df) value was measured by a dielectric loss tangent method using a dielectric constant measurement device (trade name "Concept 40 Dielectric/Impedance Spectrometer” manufactured by Novocontrol Technologies) . The results are shown in Table 2.
  • Each component was blended at an amount blended (unit: parts by mass of solids) shown in Table 3, kneaded with a 3-roll mill, and added with carbitol acetate so that the solids concentration was 70 %by mass to produce a photosensitive resin composition.
  • FA-321M (trade name) : 2, 2-bis (4- (methacryloxypentaethoxy) phenyl) propane (manufactured by Hitachi Chemical Co., Ltd. )
  • FA-MECH (trade name) : (2-hydroxy-3-chloro) propyl-2-methacryloyloxyethyl phthalate (manufactured by Hitachi Chemical Co., Ltd. )
  • BCIM (trade name) : 2, 2'-bis (2-chlorophenyl) -4, 4', 5, 5'-tetraphenylbiimidazole (manufactured by Hampford Research Inc. )
  • the photosensitive resin composition was applied onto a PET film using an applicator, and dried at 80°C for 15 minutes to form a photosensitive layer having a thickness of 100 to 150 ⁇ m.
  • the photosensitive layer was exposed by irradiation at 100 mJ/cm 2 using an exposure machine (trade name "EXM-1201" manufactured by ORC Manufacturing Co., Ltd. ) .
  • the photosensitive layer after exposure was peeled from the PET film to obtain a uncured film.
  • the photosensitive layer after exposure was cured at 170°C for 2 hours and peeled from the PET film to obtain a cured film.
  • the Df value of the uncured and cured films were measured by the dielectric loss tangent method. The results are shown in Table 3.
  • 100A multilayer printed wiring board; 101: copper-clad laminate; 102 and 107: wiring pattern; 103: interlayer insulating film; 104: opening; 105: seed layer; 106: resin pattern; 108: solder resist.

Abstract

The present disclosure relates to a method for forming a cured film, wherein the method includes a step of forming a photosensitive layer on a substrate using a photosensitive resin composition containing a carboxy group-containing resin, a photopolymerizable compound having an ethylenically unsaturated group, and a photopolymerization initiator; a step of exposing the photosensitive layer to a predetermined pattern; a step of obtaining a resin pattern by developing and removing the photosensitive layer in an unexposed area with an alkali aqueous solution; and a step of heat-treating the resin pattern at a temperature of 140°C or more to eliminate the carboxy group.

Description

METHOD FOR FORMING CURED FILM Technical Field
The present disclosure relates to a method for forming a cured film.
Background Art
In recent years, with the advancement of performance of electronic devices (miniaturization, weight reduction and multifunctionalization) , the increase in density of multilayer printed wiring boards by the increase in the number of circuit layers and miniaturization of wiring has progressed. Particularly, the increase in density of semiconductor package substrates such as BGA (ball grid array) and CSP (chip size package) on which semiconductor chips are mounted is remarkable, not only the miniaturization of the wiring but also thinning of the insulating film and further reduction in diameter of a via (also referred to as via hole) for interlayer connection have been required.
An example of a method for manufacturing the printed wiring board adopted conventionally includes the method for manufacturing the multilayer printed wiring board by the buildup method which laminates and forms an interlayer insulation layer and a conductor circuit layer one by one (for example, refer to Patent Literature 1) . On the other hand, along with the miniaturization of circuits, a semi-additive method of forming circuits by plating has become mainstream in manufacturing of multilayer printed wiring boards in  recent years.
Citation List
Patent Literature
[Patent Literature 1] JP 07-304931 A
Summary of Invention
Technical Problem
A photosensitive resin composition is used as a material for forming an interlayer insulating layer. In order to improve the alkali developability in forming a resin pattern, the photosensitive resin composition generally contains a component having an acidic group such as a carboxy group. With miniaturization of circuits, multilayer printed wiring boards are required to be excellent in low dielectric characteristics (low dielectric constant and low dielectric loss tangent) . However, when a carboxy group is present in a cured film formed by curing the resin pattern, the low dielectric characteristics required for multilayer printed wiring boards tend to be difficult to be obtained. Therefore, the cured film formed using the photosensitive resin composition containing the component having a carboxy group requires improving low dielectric characteristics.
An object of the present invention is to provide a method for forming a cured film having excellent low dielectric characteristics.
Solution to Problem
The present invention relates to a method for forming a cured film, wherein the method includes a step of forming a photosensitive layer on a substrate using a photosensitive resin composition containing a carboxy group-containing resin, a photopolymerizable compound  having an ethylenically unsaturated group, and a photopolymerization initiator; a step of exposing the photosensitive layer to a predetermined pattern; a step of obtaining a resin pattern by developing and removing the photosensitive layer in an unexposed area with an alkali aqueous solution; and a step of heat-treating the resin pattern at a temperature of 140℃ or more to eliminate the carboxy group.
Advantageous Effects of Invention
The present invention can provide a method for forming a cured film having excellent low dielectric characteristics.
Brief Description of Drawings
Figure 1 is a schematic view showing one aspect of a manufacturing process of a multilayer printed wiring board according to the present embodiments.
Description of Embodiments
Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments
In the present description, the term "step" includes not only an independent step, but also a step that cannot be clearly distinguished from another step as long as the intended effect of the step is achieved. The numerical range shown using "to" shows the range which includes the numerical values described before and after "to" as the minimum value and the maximum value, respectively. The term "layer" includes not only a structure of a shape formed on the entire surface but also a structure of a shape formed in part when it is observed as a plan view. " (Meth) acrylic acid" means at least one of "acrylic acid" and  "methacrylic acid" corresponding thereto. The same applies to other similar expressions such as (meth) acryloyl.
In the present description, when a plurality of substances corresponding to each component are present, unless otherwise specified, the amount of each component in the photosensitive resin composition means the total amount of the plurality of the substances present in the photosensitive resin composition. In the numerical range described in the present description, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in Examples. Moreover, the aspect which arbitrarily combines the matters described in this description is also included in this invention. In the present description, "solids" refers to non-volatile components excluding volatiles such as water and solvents contained in the photosensitive resin composition. That is, "solids" refers to components other than the solvent which remains without volatilization in drying of the photosensitive resin composition described below, and also includes liquid, millet jelly-like, and wax components at room temperature (25℃) .
[Method for forming cured film]
The method for forming a cured film (resist pattern) according to the present embodiments includes a step of forming a photosensitive layer on a substrate using a photosensitive resin composition containing a carboxy group-containing resin, a photopolymerizable compound having an ethylenically unsaturated group, and a photopolymerization initiator; a step of exposing the photosensitive layer to a predetermined pattern; a step of obtaining a resin pattern by developing and removing  the photosensitive layer in an unexposed area with an alkali aqueous solution; and a step of heat-treating the resin pattern at a temperature of 140℃ or more to eliminate the carboxy group.
According to the method for forming the cured film, the heat treatment at 140℃ or more eliminates at least a part of the carboxy group derived from the carboxy group-containing resin included in the resin pattern, and thereby improves low dielectric characteristics of the cured film after the heat treatment. Hereinafter, the method for forming the cured film according to the present embodiments is described in detail.
A substrate such as a copper-clad laminate board is provided, and a photosensitive layer is formed on the substrate. The substrate may be coated with the photosensitive resin composition using methods such as a printing method, a spin coating method, a spraying method, a jet dispensing method, an inkjet method, a roll coating method, a curtain coating method, and an electrostatic coating method. The photosensitive layer can be provided by drying a coating film at 60 to 110℃, the coating film being formed by coating the substrate with the photosensitive resin composition.
The photosensitive resin composition may be used in the form of a film (photosensitive film) described below. The photosensitive layer may also be provided by laminating the photosensitive layer of the photosensitive film on the substrate using a laminator. The lamination may be performed, for example, by preheating the photosensitive film and the substrate, as required, and then performed at a temperature of 70 to 130℃, a pressure of 0.1 to 1.0 MPa, and a reduced pressure of air  pressure 20 mmHg (26.7 hPa) or less. The type of the lamination may be batch or continuous by the roll.
The photosensitive layer is exposed to a predetermined pattern through a predetermined mask. The exposure method is not particularly limited, and for example may adopt a method of imagewise irradiating actinic light through a negative or positive mask pattern referred to as artwork (mask exposure method) and may adopt a method of imagewise irradiating actinic light by direct drawing exposure method such as LDI (Laser Direct Imaging) exposure method or DLP (Digital Light Processing) exposure method.
A known light source can be used as a light source of actinic light. Examples of the light source include a light source that effectively emits ultraviolet light or visible light such as gas laser such as carbon arc lamp, mercury vapor arc lamp, high pressure mercury lamp, xenon lamp, and argon laser; solid laser such as YAG laser; and semiconductor laser.
The exposure dose is appropriately selected depending on the light source to be used, the thickness of the photosensitive layer, and the like. For example, when the thickness of the photosensitive layer is 1 to 100 μm and ultraviolet irradiation from a high-pressure mercury lamp is used, the exposure dose may be 10 to 1000 mJ/cm 2 or 15 to 500 J/m 2.
After exposure, when a support film is present on the photosensitive layer, the support film is removed and then the unexposed area is removed (developed) with an alkaline developer to obtain a resin pattern. Examples of the development method include methods using a dip method, a paddle method, a spray method,  brushing, slapping, scrubbing, swing immersion, or the like. From the viewpoint of improving resolution, a spray method is preferable, and a high pressure spray method is more preferable.
Examples of the alkaline developer include an alkaline aqueous solution in which an alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, tetramethylammonium hydroxide or choline is dissolved in water to a concentration of about 1 to 10%by mass; and ammonia water.
To develop low dielectric characteristics, the resin pattern is heat-treated to obtain a cured film (resist pattern) . Heat-treating the resin pattern eliminates at least a part of the carboxy group. Elimination of the carboxy group can enhance the low dielectric characteristics of the cured film. Thus, the heat treatment is performed under the condition of a temperature or more at which the elimination of the carboxy group occurs. For the heating temperature, 140 to 250℃is preferable, 150 to 230℃ is more preferable, and 160 to 200℃ is still more preferable. For the heating time, about 30 minutes to 10 hours is preferable, 1 hour to 5 hours is more preferable, and 1.5 hours to 3 hours is still more preferable.
(Photosensitive resin composition)
The photosensitive resin composition according to the present embodiments contains (A) an alkali-soluble resin (hereinafter sometimes referred to as "component (A) " ) , and (B) a photopolymerizable compound having an ethylenically unsaturated group (hereinafter sometimes referred to as "component (B) " ) , and (C) a photopolymerization initiator (hereinafter sometimes referred to as  "component (C) " ) . Hereinafter, each component which the photosensitive resin composition may contain is explained in detail.
< (A) Alkali-soluble resin>
The component (A) is a resin soluble in an alkali aqueous solution. The alkali aqueous solution is an alkaline aqueous solution such as tetramethyl ammonium hydroxide (TMAH) aqueous solution, metal hydroxide aqueous solution, metal carbonate aqueous solution, and organic amine aqueous solution. The solubility of the component (A) in an alkali aqueous solution can be confirmed, for example, as follows.
A substrate such as a silicon wafer is spin-coated with a varnish obtained by dissolving the component (A) in an arbitrary solvent to form a coating film having about 5 μm thickness. This is immersed in any of TMAH aqueous solution, metal hydroxide aqueous solution, metal carbonate aqueous solution, or organic amine aqueous solution at 20 to 25℃. As a result, when the coating film can be dissolved uniformly, the component (A) can be regarded as soluble in an alkaline aqueous solution.
The component (A) includes the carboxy group-containing resin. The carboxy group-containing resin is not particularly limited as long as it has a structure in which the carboxy group is eliminated at a temperature of 140℃ or more. The carboxy group-containing resin may be composed of only one resin, or may be composed of two or more resins.
As the carboxy group-containing resin, a resin having a group represented by the following formula (1) (hereinafter, sometimes  referred to as "component (A1) " ) may be used.
Figure PCTCN2019089958-appb-000001
Since the component (A1) has a group represented by formula (1) , it has excellent solubility in an alkali aqueous solution. The component (A1) is heat-treated at 140℃ or more, thereby eliminating at least a part of the carboxy group from the group represented by formula (1) to improve low dielectric characteristics after the heat treatment. The group represented by formula (1) may be referred to as a β-ketocarboxy group.
The component (A1) may be a resin having a structural unit based on the carboxy group-containing compound having a (meth) acryloyl group and the group represented by formula (1) . The carboxy group-containing compound may be a compound having a structure represented by the following formula (3) .
Figure PCTCN2019089958-appb-000002
In the formula, R 1 represents a hydrogen atom or a methyl group and L 1 represents an alkylene group having 1 to 10 carbon atoms. From the viewpoint of improving the alkali solubility, L 1 is preferable to be an alkylene group having 1 to 6 carbon atoms, more preferable to be an alkylene group having 1 to 4 carbon atoms, and still more preferable to be an alkylene group having 2 or 3 carbon atoms.
The compound represented by formula (3) can be obtained, for example, by reacting a (meth) acryloyl compound having a hydroxyl group with malonic acid. Examples of the (meth) acryloyl compound having a hydroxyl group include hydroxyalkyl (meth) acrylates such as hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyheptyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxynonyl (meth) acrylate, and hydroxydecyl (meth) acrylate.
From the viewpoint of further improving the solubility in an alkali aqueous solution, the content of the carboxy group-containing compound may be 5%by mass or more, 8%by mass or more, 10%by mass or more, or 12%by mass or more, based on the total amount of the monomers constituting the carboxy group-containing resin. From the viewpoint of further improving the low dielectric characteristics, the content of the carboxy group-containing compound may be 90%by mass or less, 85%by mass or less, 80%by mass or less, or 75%by mass or less.
From the viewpoint of further improving the low dielectric characteristics, the above carboxy group-containing resin may further have a structural unit based on an aromatic vinyl compound. Examples of the aromatic vinyl compound include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-methoxystyrene, m-methoxystyrene, and p-methoxystyrene.
The above carboxy group-containing resin according to the present embodiments may further have a structural unit based on a  (meth) acrylate. The (meth) acrylate may be a compound having an alkyl group or a hydroxyalkyl group.
Examples of the (meth) acrylate include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, and decyl (meth) acrylate; and hydroxyalkyl (meth) acrylates such as hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyheptyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxynonyl (meth) acrylate, and hydroxydecyl (meth) acrylate.
The component (A1) may be an epoxy resin derivative having the group represented by formula (1) . The epoxy resin derivative may be, for example, a compound obtained by reacting malonic acid with an esterified product of an epoxy resin and an ethylenically unsaturated group-containing monocarboxylic acid. Examples of the epoxy resin include a phenol novolac type epoxy resin, a bisphenol type epoxy resin, and a dicyclopentadiene type epoxy resin.
As the carboxy group-containing resin, a resin having a group represented by the following formula (2) (hereinafter, sometimes referred to as "component (A2) " ) may be used.
Figure PCTCN2019089958-appb-000003
In the formula (2) , X represents a group having a cycloalkane ring, a cycloalkene ring, or an aromatic ring. The group represented by formula (2) may be at least one group selected from the group consisting of groups represented by the following formulas (2a) , (2b) , and (2c) .
Figure PCTCN2019089958-appb-000004
The component (A2) may be an epoxy resin derivative having the group represented by formula (2) .
From the viewpoint of improving heat resistance, the weight average molecular weight (Mw) of the carboxy group-containing resin may be 1000 or more, 2000 or more, or 3000 or more. From the viewpoint of being suitably developable, Mw of the carboxy group-containing resin may be 30000 or less, 25000 or less, or 18000 or less. Mw can be measured, for example, by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.
The component (A) may further include an alkali-soluble resin other than the components (A1) and (A2) . The alkali-soluble resin may be a resin having a phenolic hydroxyl group. Examples of the resin having a phenolic hydroxyl group include polyhydroxystyrene, hydroxystyrene-based resins such as copolymers including hydroxystyrene as a monomer unit, phenolic resins, polybenzoxazole precursors such as poly (hydroxyamide) , poly (hydroxyphenylene) ether,  and polynaphthol.
From the viewpoint of being suitably developable, the acid value of the component (A) may be 30 mg KOH/g or more, 40 mg KOH/g or more, or 50 mg KOH/g or more, and from the viewpoint of improving the adhesion (developer resistance) of the cured product of the photosensitive resin composition, it may be 250 mg KOH/g or less, 230 mg KOH/g or less, or 200 mg KOH/g or less. The acid value of the component (A) can be adjusted by the content of a structural unit based on the carboxy group-containing compound.
From the viewpoint of further improving the alkali developability, the content of the component (A) may be 50 parts by mass or more, 60 parts by mass or more, or 70 parts by mass or more, per 100 parts by mass in total of the component (A) , the component (B) , and the component (C) . From the viewpoint of improving sensitivity and resolution, the content of the component (A) may be 95 parts by mass or less, 90 parts by mass or less, or 85 parts by mass or less.
< (B) Photopolymerizable compound having ethylenically unsaturated group>
The component (B) is a compound having a functional group having an ethylenically unsaturated bond such as a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenyl ethynyl group, a maleimide group, a nadimide group, and a (meth) acryloyl group as a functional group which exhibits photopolymerization. The component (B) is not particularly limited as long as it is a compound having one or more ethylenically unsaturated groups. As a functional group which exhibits photopolymerization, a  (meth) acryloyl group is preferable. The component (B) may be used singly or in combination of two or more.
Examples of the photopolymerizable compound having one ethylenically unsaturated group include (meth) acrylic acids, alkyl (meth) acrylates, and phthalic acid-based (meth) acrylate compounds.
Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and hydroxylethyl (meth) acrylate.
From the viewpoint of suitably improving resolution, adhesion, and resist shape, the component (B) may include a phthalic acid-based compound. Examples of the phthalic acid-based compound include γ-chloro-β-hydroxypropyl-β'- (meth) acryloyloxyethyl-o-phthalate (aka: 3-chloro-2-hydroxypropyl-2- (meth) acryloyloxyethylphthalate) , β-hydroxyethyl-β'- (meth) acryloyloxyethyl-o-phthalate, and β-hydroxypropyl-β'- (meth) acryloyloxyethyl-o-phthalate.
Examples of the photopolymerizable compound having two ethylenically unsaturated groups include polyethylene glycol di(meth) acrylate, trimethylolpropane di (meth) acrylate, polypropylene glycol di (meth) acrylate, 2, 2-bis (4- (meth) acryloxypolyethoxypolypropoxyphenyl) propane, bisphenol A diglycidyl ether di (meth) acrylate, and alkylene oxide-modified bisphenol A di (meth) acrylate.
From the viewpoint of improving alkali developability and resolution, the component (B) may include an alkylene oxide-modified bisphenol A di (meth) acrylate. Examples of the alkylene oxide modified bisphenol A di (meth) acrylate include  2, 2-bis (4- ( (meth) acryloxypolyethoxy) phenyl) propane (2, 2-bis (4- ( (meth) acryloxypentaethoxy) phenyl) propane or the like) , 2, 2-bis (4- ( (meth) acryloxypolypropoxy) phenyl) propane, 2, 2-bis (4- ( (meth) acryloxypolybutoxy) phenyl) propane, and 2, 2-bis (4- ( (meth) acryloxypolyethoxypolypropoxy) phenyl) propane.
Examples of the photopolymerizable compound having 3 or more ethylenically unsaturated groups include (meth) acrylate having a skeleton derived from trimethylolpropane such as trimethylolpropane tri(meth) acrylate; (meth) acrylate having a skeleton derived from tetramethylolmethane such as tetramethylolmethane tri (meth) acrylate and tetramethylolmethane tetra (meth) acrylate; (meth) acrylate having a skeleton derived from pentaerythritol such as pentaerythritol tri(meth) acrylate and pentaerythritol tetra (meth) acrylate; (meth) acrylate having a skeleton derived from dipentaerythritol such as dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate; (meth) acrylate having a skeleton derived from ditrimethylolpropane such as ditrimethylolpropane tetra (meth) acrylate; and (meth) acrylate having a skeleton derived from diglycerin. Among them, from the viewpoint of enhancing the chemical resistance after curing (exposure) and increasing the difference in developer resistance between the exposed area and the unexposed area, (meth) acrylate compounds having a skeleton derived from dipentaerythritol are preferable and dipentaerythritol penta (meth) acrylate is more preferable.
From the viewpoint of improving the alkali developability of the unexposed area of the photosensitive layer and improving the adhesive strength of the exposed area, the component (B) may include a  photopolymerizable compound having an ethylenically unsaturated group and an acid-modified group. Examples of the acidic group to be modified include a carboxy group, a sulfo group, and a phenolic hydroxyl group, and among them, the carboxy group is preferable.
Examples of the photopolymerizable compound having an ethylenically unsaturated group and an acidic group include styrene-maleic acid-based resin and epoxy derivative containing an acid-modified vinyl group.
The styrene-maleic acid-based resin is a hydroxyethyl (meth) acrylate modified product of a styrene-maleic anhydride copolymer. The epoxy derivative containing an acid-modified vinyl group is a compound obtained by reacting a compound having epoxy resin modified with vinyl group-containing organic acid with saturated or unsaturated group-containing polybasic acid anhydride.
The epoxy resin is not particularly limited as long as it is a compound having two or more epoxy groups. Examples of the epoxy resin include a glycidyl ether type epoxy resin, a glycidylamine type epoxy resin, and a glycidyl ester type epoxy resin. Among them, from the viewpoint of reliability in mounting semiconductor chips, a bisphenol-based novolac type epoxy resin is preferable and a bisphenol F novolac type epoxy resin is more preferable.
The vinyl group-containing organic acid is not particularly limited, and may be a vinyl group-containing monocarboxylic acid. Examples of the vinyl group-containing monocarboxylic acid include acrylic acid derivatives such as acrylic acid, a dimer of acrylic acid, methacrylic acid, β-furfurylacrylic acid, β-styrylacrylic acid, cinnamic  acid, crotonic acid, and α-cyanocinnamic acid; a half ester compound which is a reaction product of a hydroxyl group-containing acrylate and a dibasic acid anhydride; and a half ester compound which is a reaction product of a vinyl group-containing monoglycidyl ether or a vinyl group-containing monoglycidyl ester with a dibasic acid anhydride.
An acid-modified vinyl group-containing epoxy derivative may have a group represented by formula (1) or (2) . Use of a carboxy group-containing resin as the component (B) can improve the alkali developability of the unexposed area of the photosensitive layer.
< (C) Photopolymerization initiator>
The component (C) is not particularly limited as long as it is a component capable of polymerizing the component (B) , and can be appropriately selected from commonly used photopolymerization initiators. The component (C) can be used singly or in combination of two or more.
Examples of the component (C) include benzoin compounds such as benzoin, benzoin methyl ether, and benzoin isopropyl ether; acetophenone compounds such as acetophenone, 2, 2-dimethoxy-2-phenylacetophenone, 2, 2-diethoxy-2-phenylacetophenone, 1, 1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone, and N, N-dimethylaminoacetophenone; anthraquinone compounds such as 2-methyl anthraquinone, 2-ethyl anthraquinone, 2-tert-butyl anthraquinone, 1-chloroanthraquinone, 2-amyl anthraquinone, and  2-aminoanthraquinone; thioxanthone compounds such as 2, 4-dimethylthioxanthone, 2, 4-diethylthioxanthone, 2-chlorothioxanthone, and 2, 4-diisopropylthioxanthone; ketal compounds such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenone compounds such as benzophenone, methylbenzophenone, 4, 4'-dichlorobenzophenone, 4, 4'-bis (diethylamino) benzophenone, Michler's ketone, and 4-benzoyl-4'-methyl diphenyl sulfide; imidazole compounds such as 2- (ο-chlorophenyl) -4, 5-diphenylimidazole dimer, 2- (ο-chlorophenyl) -4, 5-di (m-methoxyphenyl) imidazole dimer, 2- (ο-fluorophenyl) -4, 5-diphenylimidazole dimer, 2- (ο-methoxyphenyl) -4, 5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4, 5-diphenylimidazole dimer, 2, 4-di (p-methoxyphenyl) -5-phenylimidazole dimer, and 2- (2, 4-dimethoxyphenyl) -4, 5-diphenylimidazole dimer; acridine compounds such as 9-phenylacridine and 1, 7-bis (9, 9'-acridinyl) heptane; acyl phosphine oxide compounds such as 2, 4, 6-trimethyl benzoyl diphenyl phosphine oxide; and oxime ester compounds such as 1, 2-octanedione-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime) , 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone 1- (O-acetyloxime) , and 1-phenyl-1, 2-propanedione-2- [O- (ethoxycarbonyl) oxime] .
The content of the component (C) is not particularly limited. From the viewpoint of improving the sensitivity of the resin pattern, the content of the component (C) may be 0.1 parts by mass or more, 0.3 parts by mass or more, or 0.5 parts by mass or more, per 100 parts by  mass in total of the total of the component (A) , the component (B) , and the component (C) . From the viewpoint of improving the heat resistance of the resist pattern, the content of the component (C) may be 3 parts by mass or less, 2 parts by mass or less, or 1 part by mass or less.
The photosensitive resin composition according to the present embodiments may contain a photoinitiation auxiliary as component (C') with the component (C) . Examples of the photoinitiation auxiliary include tertiary amine compounds such as ethyl N, N-dimethylaminobenzoate, isoamyl N, N-dimethylaminobenzoate, pentyl-4-dimethylaminobenzoate, triethylamine, and triethanolamine. The component (C') may be used singly or in combination of two or more.
<Component (D) : acid catalyst>
The photosensitive resin composition according to the present embodiments may further contain an acid catalyst. When the resin pattern is heat-treated, the elimination of the carboxy group can be promoted by the acid catalyst. When the resin having the group represented by formula (2) is used, particularly it is preferable to use the acid catalyst together.
Examples of the component (D) include a compound (photoacid generator) that generates an acid by light (by receiving light) and a compound (thermal acid generator) that generates an acid by heating. The component (D) may be used singly or in combination of two or more.
Examples of the photoacid generator include an iodonium salt and a sulfonium salt. Examples of the sulfonium salt include  triarylsulfonium salts such as triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, and triphenylsulfonium hexafluoroantimonate. Examples of the thermal acid generator include an onium salt. Examples of the onium salt include trimethylsulfonium methylsulfate, 2, 6-dimethylpyridinium p-toluenesulfonate, 2-chloro-1-methylpyridinium p-toluenesulfonate, and 2-fluoro-1-methylpyridinium p-toluenesulfonate.
<Other components>
The photosensitive resin composition according to the present embodiments, in addition to the components (A) to (D) , may further contain solvent, epoxy resin, elastomer, thermal polymerization initiator, inorganic filler, polymerization inhibitor, thickener, antifoaming agent, silane coupling agent, flame retardant, and the like.
The photosensitive resin composition according to the present embodiments contains a solvent and thereby can be easily applied on a substrate to form a coating film having uniform thickness. Examples of the solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, propylene glycol monoethyl ether acetate, butyl cellosolve acetate, and carbitol acetate; aliphatic hydrocarbons such as octane and decane; and petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent  naphtha. The solvents may be used singly or in combination of two or more.
Examples of the epoxy resin include a bisphenol type epoxy resin, a bisphenol novolac type epoxy resin, a phenol aralkyl type epoxy resin, a biphenyl aralkyl type epoxy resin, a stilbene type epoxy resin, a dicyclopentadiene type epoxy resin, a naphthalene type epoxy resin, a biphenyl type epoxy resin, a biphenylaralkyl type epoxy resin, a xylylene type epoxy resin, a dihydroanthracene type epoxy resin, a dicyclopentadiene type epoxy resin, an alicyclic epoxy resin, an aliphatic chain epoxy resin, and a rubber modified epoxy resin.
Examples of the elastomer include a styrene-based elastomer, an olefin-based elastomer, a polyester-based elastomer, a urethane-based elastomer, a polyamide-based elastomer, an acrylic elastomer, and a silicone-based elastomer.
As the thermal polymerization initiator, an organic peroxide or an azo compound may be used. Examples of the organic peroxide include hydroperoxides such as diisopropylbenzene hydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide; dialkylperoxides such as α, α-bis (t-butylperoxy-m-isopropyl) benzene, dicumyl peroxide, 2, 5-dimethyl-2, 5-bis (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, and 2, 5-dimethyl-2, 5-bis (t-butylperoxy) hexyne-3, t-butylperoxy-2-ethylhexanoate; ketone peroxides; peroxyketals such as n-butyl 4, 4-di- (t-butylperoxy) valerate; diacyl peroxides; peroxy dicarbonates; and peroxyesters. Examples of the azo compounds include 2, 2'-azobisisobutyronitrile, 2, 2'-azobis (2-cyclopropylpropionitrile) , and 2, 2'-azobis (2, 4-dimethyl  valeronitrile) .
Examples of the inorganic filler include silica, alumina, titania, tantalum oxide, zirconia, silicon nitride, barium titanate, barium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, lead titanate, lead zirconate titanate, lead lanthanum zirconate titanate, gallium oxide, spinel, mullite, cordierite, talc, aluminum titanate, yttria-containing zirconia, barium silicate, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, zinc oxide, magnesium titanate, hydrotalcite, mica, calcined kaolin, and carbon.
As a pigment, a coloring agent which develops a desired color can be appropriately selected and used, and examples of the pigment include phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black.
Examples of the polymerization inhibitor include hydroquinone, methyl hydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol. Examples of the thickener include benton and montmorillonite. Examples of the antifoaming agent include silicone-based antifoaming agent, fluorine-based antifoaming agent, and vinyl resin-based antifoaming agent. Examples of the flame retardant include a brominated epoxy compound, an acid-modified brominated epoxy compound, an antimony compound, a phosphate compound, an aromatic condensed phosphate, and a halogen-containing condensed phosphate.
The photosensitive resin composition according to the present embodiments can be prepared by mixing each component with a roll  mill, a bead mill, or the like. The photosensitive resin composition according to the present embodiments is excellent in alkali developability and can form a cured film excellent in low dielectric characteristics. The photosensitive resin composition can be suitably used for forming a resist pattern, and can be particularly suitably used for the method for manufacturing a multilayer printed wiring board described below.
(Photosensitive film)
The photosensitive film according to the present embodiments includes a support film and the photosensitive layer formed from the above-described photosensitive resin composition. The photosensitive film includes a support film and a photosensitive layer formed on the support film.
The photosensitive film can be prepared by applying the photosensitive resin composition according to the present embodiments on a support film with known coating devices such as a bar coater, a reverse roll coater, a gravure roll coater, a comma coater, a curtain coater, a kiss coater, and a die coater and then by drying a coating film to form a photosensitive layer.
Examples of the support film include polyester films such as polyethylene terephthalate and polybutylene terephthalate and polyolefin films such as polypropylene and polyethylene. The thickness of the support film may be, for example, 5 to 100 μm, 5 to 60 μm, or 15 to 45 μm.
The thickness of the photosensitive layer is not particularly limited, but may be 1 to 100 μm, 1 to 50 μm, or 5 to 40 μm from the  viewpoint of thinning the multilayer printed wiring board.
The drying of the coating film can be performed using hot air drying, or drying using far infrared radiation or near infrared radiation. The drying temperature may be, for example, 60 to 130℃, 70 to 120℃, or 80 to 110℃. The drying time may be, for example, 1 to 60 minutes, 2 to 30 minutes, or 5 to 20 minutes.
The photosensitive film according to the present embodiments can also laminate a protective film on the surface opposite to the surface in contact with the support film of the photosensitive layer. As a protective film, for example, polyolefin films such as polyethylene and polypropylene may be used. The protective film may be the same film as the support film.
[Multilayer printed wiring board]
The cured product of the photosensitive resin composition of the present embodiments can be suitably used, for example, as a surface protective film (overcoat film) and/or an interlayer insulating film (passivation film) of a semiconductor element, or a solder resist and/or an interlayer insulating layer in a multilayer printed wiring board.
Figure 1 is a view showing a method for manufacturing a multilayer printed wiring board including a cured product of the photosensitive resin composition according to the present embodiments as a solder resist and/or an interlayer insulating film. The multilayer printed wiring board 100A shown in (f) of Figure 1 has a wiring pattern on the surface and inside. The multilayer printed wiring board 100A can be obtained by appropriately forming a wiring pattern by an etching method or a semi-additive method, in addition to laminating a  copper-clad laminate, an interlayer insulating film, a metal foil, and the like. Hereinafter, a method for manufacturing the multilayer printed wiring board 100A will be briefly described based on Figure 1.
The interlayer insulating film 103 is formed on both surfaces of the copper-clad laminate 101 having a wiring pattern 102 on the surface (refer to Figure 1 (a) ) . The interlayer insulating film 103 may be formed by printing the above-described photosensitive resin composition using a screen printer or a roll coater, and can also be formed by providing the above-described photosensitive film in advance and bonding the photosensitive layer of the photosensitive film to the surface of the printed wiring board using a laminator.
The region other than the portion required to be electrically connected to the outside in the interlayer insulating film 103 is exposed and developed to form the opening 104 (refer to Figure 1 (b) ) . Smear (residue) around the opening 104 is removed by desmear treatment. The size (diameter) of the opening 104 is not particularly limited, and can be arbitrarily selected, for example, in the range of 15 to 300 μm. The seed layer 105 is formed on the interlayer insulating film 103 and the opening 104 by the electroless plating method (refer to Figure 1 (c) ) . The thickness of the seed layer 105 may be about 0.1 to 2.0 μm. A photosensitive layer formed from the above-described photosensitive resin composition is formed on the seed layer 105, and predetermined portions are exposed and developed to form the resin pattern 106 (refer to Figure 1 (d) ) . As required, an operation of removing the development residue of the photosensitive layer may be performed using plasma or the like. The wiring pattern 107 is formed by the  electro-plating method and the resin pattern 106 is removed by a peeling solution, and then the seed layer 105 between the wirings is removed by etching (refer to Figure 1 (e) ) .
The multilayer printed wiring board 100A can be produced by repeatedly performing the above operation and forming the solder resist 108 including the cured product of the above-described photosensitive resin composition on the outermost surface (refer to Figure 1 (f) ) . In the multilayer printed wiring board 100A obtained in this manner, the semiconductor element is mounted at the corresponding position, and electrical connection can be secured.
[Semiconductor package]
A semiconductor package mounting a semiconductor element can be produced in the printed wiring board according to the present embodiments. The semiconductor package can be manufactured by mounting semiconductor elements such as a semiconductor chip and memory at a predetermined position of the above-described printed wiring board and sealing the semiconductor elements with a sealing resin or the like.
Examples
Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not limited to these Examples.
(1) Carboxy group-containing compound
(Synthesis Example a1)
Malonic acid (20.8 g, 0.20 mol) , 2-hydroxyethyl methacrylate  (26.0 g, 0.20 mol) , boric acid (4.9 g, 0.08 mol) , and 60 mL of acetonitrile were poured into 250 mL three-necked flask equipped with a stirrer, a nitrogen introduction pipe, a reflux condenser, a dropping funnel, and a thermometer to perform the reaction at 75℃ for 24 hours under a nitrogen atmosphere.
After removing acetonitrile from the reaction solution with an evaporator, the solution was poured into 100 mL of water, and the separated oily component was collected. 15 mL of chloroform was added to the aqueous solution from which the oily component was removed, and liquid separation operation was performed three times to collect an organic layer. The oily component and the organic layer were mixed and washed with a saturated saline solution to obtain a chloroform solution of the product. 50 mL of a 0.16%by mass sodium carbonate aqueous solution was added to the chloroform solution of the product to collect the aqueous layer. The collected aqueous layer was washed with chloroform to obtain an aqueous solution of the product.
After 15 g of hydrochloric acid was added to the aqueous solution of the product and the separated oil layer was collected, chloroform was added to the remaining aqueous solution of the product to perform a liquid separation operation, and the chloroform layer was collected. The oil layer and the chloroform layer were mixed, washed by adding water, and then concentrated under reduced pressure to remove chloroform to obtain a carboxy group-containing compound (compound in which R 1 is a hydrogen atom and L 1 is an ethylene group in formula (3) , hereinafter referred to as "compound a" ) . The yield was about 35 to 40%.
(2) Carboxy group-containing resin
(Synthesis Example 1)
25 g of the compound a, 75 g of 1, 4-dioxane, and 0.5 g of 2, 2'-azodiisobutyronitrile (AIBN) were poured into 100 mL four-necked flask equipped with a stirrer, a nitrogen introduction pipe, a reflux condenser, a dropping funnel, and a thermometer, and were stirred at 75℃ for 6 hours under a nitrogen atmosphere and then cooled to room temperature to obtain a solution of a carboxy group-containing resin (hereinafter referred to as "polymer A" ) .
(Synthesis Example 2)
139 g of propylene glycol methyl ether (MFG) and 93 g of toluene (TLS) were poured into 400 mL four-necked flask equipped with a stirrer, a nitrogen introduction pipe, a reflux condenser, a dropping funnel, and a thermometer, and were heated to 80℃ while stirring under a nitrogen atmosphere. A mixture of 142 g of styrene, 25.2 g of the compound a and 1.41 g of AIBN was dropped for 80 minutes from the dropping funnel, and then a mixed solution of 6 g of MFG, 4 g of TLS, and 0.28 g of AIBN was dropped to perform a reaction. The reaction solution was stirred for 2 hours, heated to 95℃, and stirred for 1.5 hours, and then cooled to room temperature to obtain a solution of a carboxy group-containing resin (hereinafter referred to as "polymer B" ) .
(Synthesis Example 3)
A solution of a carboxy group-containing resin (hereinafter referred to as "polymer C" ) was obtained in the same manner as in Synthesis Example 2, except that a mixture of 36 g of styrene, 84 g of  the compound a, and 1.01 g of AIBN was dropped.
(Synthesis Example 4)
A solution of the polymer B and a solution of the polymer C were mixed at a ratio of 80 parts by mass of the polymer B and 20 parts by mass of the polymer C to obtain a solution of polymer E.
(Synthesis Example 5)
A solution of the polymer B and a solution of the polymer C were mixed at a ratio of 54 parts by mass of the polymer B and 46 parts by mass of the polymer C to obtain a solution of polymer F.
(Synthesis Example 6)
A solution of a carboxy group-containing resin (hereinafter referred to as "polymer D" ) was obtained in the same manner as in Synthesis Example 2, except that a mixture of 142 g of styrene, 25.2 g of methacrylic acid, and 1.41 g of AIBN was dropped.
(Acid value)
The acid value of the polymers A to F was calculated from the structure of monomer constituting the polymer and copolymerization ratio.
(Evaluation of alkali solubility)
A solution of the polymers A to F was applied on a substrate using an applicator and dried at 80℃ for 10 minutes to form a resin film having a thickness of 10 to 20 μm. The resin film was developed at 30℃ for 50 seconds, 80 seconds, and 120 seconds, respectively, using 1.0%by mass of a sodium carbonate aqueous solution. The average dissolution rate of the resin film was calculated from the thickness of the resin film after development. The results are shown in Table 1.
Dissolution rate (μm/s) = [thickness before development (μm) -thickness after development (μm) ] /development time (s)
[Table 1]
Figure PCTCN2019089958-appb-000005
(Elimination of carboxy group)
A resin film was formed by using a solution of the polymer A and drying at 80℃ for 10 minutes and then the resin film was heat-treated at 170℃ for 2 hours. The infrared absorption spectra of the resin film before and after the heat treatment were measured and the elimination of a carboxy group after the heat treatment was determined by the spectral change derived from the carboxy group.
(Dielectric loss tangent)
A PET film was coated with a solution of the polymer A using an applicator and dried at 80℃ for 10 minutes to form a resin film having a thickness of 100 to 150 μm. The resin film was heat-treated at 170℃ for 2 hours. About the resin film before and after the heat treatment, the dielectric loss tangent (Df) value was measured by a dielectric loss tangent method using a dielectric constant measurement device (trade name "Concept 40 Dielectric/Impedance Spectrometer" manufactured by Novocontrol Technologies) . The results are shown in Table 2.
[Table 2]
Figure PCTCN2019089958-appb-000006
(3) Photosensitive resin composition
Each component was blended at an amount blended (unit: parts by mass of solids) shown in Table 3, kneaded with a 3-roll mill, and added with carbitol acetate so that the solids concentration was 70 %by mass to produce a photosensitive resin composition.
The details of each material in Table 3 are as follows.
(B) Photopolymerizable compound
FA-321M (trade name) : 2, 2-bis (4- (methacryloxypentaethoxy) phenyl) propane (manufactured by Hitachi Chemical Co., Ltd. )
FA-MECH (trade name) : (2-hydroxy-3-chloro) propyl-2-methacryloyloxyethyl phthalate (manufactured by Hitachi Chemical Co., Ltd. )
(C) Photopolymerization initiator
BCIM (trade name) : 2, 2'-bis (2-chlorophenyl) -4, 4', 5, 5'-tetraphenylbiimidazole (manufactured by Hampford Research Inc. )
(Dielectric loss tangent)
The photosensitive resin composition was applied onto a PET film using an applicator, and dried at 80℃ for 15 minutes to form a photosensitive layer having a thickness of 100 to 150 μm. The photosensitive layer was exposed by irradiation at 100 mJ/cm 2 using an exposure machine (trade name "EXM-1201" manufactured by ORC  Manufacturing Co., Ltd. ) . The photosensitive layer after exposure was peeled from the PET film to obtain a uncured film. The photosensitive layer after exposure was cured at 170℃ for 2 hours and peeled from the PET film to obtain a cured film. The Df value of the uncured and cured films were measured by the dielectric loss tangent method. The results are shown in Table 3.
[Table 3]
Figure PCTCN2019089958-appb-000007
Reference Signs List
100A: multilayer printed wiring board; 101: copper-clad laminate; 102 and 107: wiring pattern; 103: interlayer insulating film; 104: opening; 105: seed layer; 106: resin pattern; 108: solder resist.

Claims (5)

  1. A method for forming a cured film, comprising:
    a step of forming a photosensitive layer on a substrate using a photosensitive resin composition containing a carboxy group-containing resin, a photopolymerizable compound having an ethylenically unsaturated group, and a photopolymerization initiator;
    a step of exposing the photosensitive layer to a predetermined pattern;
    a step of obtaining a resin pattern by developing and removing the photosensitive layer in an unexposed area with an alkali aqueous solution; and
    a step of heat-treating the resin pattern at a temperature of 140℃or more to eliminate the carboxy group.
  2. The method according to claim 1, wherein the photosensitive resin composition further contains an acid catalyst.
  3. The method according to claim 1 or 2, wherein the carboxy group-containing resin has a group represented by the following formula (1) .
    Figure PCTCN2019089958-appb-100001
  4. The method according to claim 1 or 2, wherein the carboxy  group-containing resin has a group represented by the following formula (2) :
    Figure PCTCN2019089958-appb-100002
    wherein X represents a group having a cycloalkane ring, a cycloalkene ring, or an aromatic ring.
  5. The method according to claim 4, wherein the group represented by the formula (2) is at least one group selected from the group consisting of groups represented by the following formulas (2a) , (2b) , and (2c) .
    Figure PCTCN2019089958-appb-100003
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001022165A1 (en) * 1999-09-17 2001-03-29 Hitachi Chemical Co., Ltd. Photosensitive resin compositions, photosensitive element containing the same, process for producing resist pattern, and process for producing printed circuit board
CN101410421A (en) * 2006-03-28 2009-04-15 富士胶片株式会社 Photopolymerization initiator, photosensitive composition, photosensitive film, photosensitive laminate, method of forming permanent pattern and printed board
US20100160474A1 (en) * 2007-09-04 2010-06-24 Cheil Industries Inc. Photosensitive Resin Composition for Color Filter and Color Filter Made Using the Same
CN102859437A (en) * 2010-04-28 2013-01-02 富士胶片株式会社 Photosensitive composition, photosensitive film, photosensitive laminate, method for forming permanent pattern, and printed board

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001022165A1 (en) * 1999-09-17 2001-03-29 Hitachi Chemical Co., Ltd. Photosensitive resin compositions, photosensitive element containing the same, process for producing resist pattern, and process for producing printed circuit board
CN101410421A (en) * 2006-03-28 2009-04-15 富士胶片株式会社 Photopolymerization initiator, photosensitive composition, photosensitive film, photosensitive laminate, method of forming permanent pattern and printed board
US20100160474A1 (en) * 2007-09-04 2010-06-24 Cheil Industries Inc. Photosensitive Resin Composition for Color Filter and Color Filter Made Using the Same
CN102859437A (en) * 2010-04-28 2013-01-02 富士胶片株式会社 Photosensitive composition, photosensitive film, photosensitive laminate, method for forming permanent pattern, and printed board

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