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

Abstract

Provided are a photosensitive composition that can be made halogen-free, a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a printed wiring board. This photosensitive composition comprises (A) a binder polymer, (B) a photopolymerizable compound, and (C1) a hexaarylbiimidazole compound containing no halogen atom in the molecular structure thereof.

Description

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

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

[0002] In the field of printed wiring board manufacturing, photosensitive resin materials are widely used as resist materials for processes such as etching and plating. Photosensitive resin materials are mainly distributed on the market in the form of liquids or laminated film photosensitive elements in which a photosensitive layer containing the photosensitive resin material is formed on a support and a protective film is further disposed thereon.

[0003] Recently, the miniaturization of circuit patterns has progressed, and the development of photosensitive resin materials that can accommodate this trend is required. The basic and important performance required of photosensitive resin materials is that they can be sufficiently exposed to light with as little exposure as possible and can be developed with high resolution. Furthermore, there is an ever-increasing demand for industrial chemical products to reduce their environmental impact and improve the safety of the working environment. As one of the goals, the development of halogen-free products is anticipated.

[0004] Hexaarylbiimidazole compounds having a chloro group are widely used as polymerization initiators in photosensitive resin materials, but these compounds have environmental concerns because they contain halogen atoms, and their performance as polymerization initiators has not been sufficient given the trend toward increasingly fine circuit patterns (see Patent Document 1).

[0005] Japanese Patent Application Publication No. 5-27436

[0006] An object of the present disclosure is to provide a photosensitive composition that can be made halogen-free, a photosensitive element, a method for forming a resist pattern, and a method for producing a printed wiring board.

[0007] The present disclosure includes the following embodiments: The present disclosure is not limited to the following embodiments.

[0008] One embodiment relates to a photosensitive composition comprising a binder polymer (A), a photopolymerizable compound (B), and a hexaarylbiimidazole compound (C1) that does not contain a halogen atom in its molecular structure.

[0009] Another embodiment relates to a photosensitive composition comprising a binder polymer (A), a photopolymerizable compound (B), and a hexaarylbiimidazole compound (C2) represented by the following general formula (1):

[0010]

[0011] [In general formula (1), R １ ~R ６ are each independently an alkyl group or an alkoxy group, and a to f are each independently 0 or an integer of 1 to 5. When a to f are an integer of 2 or more, a plurality of R Ｘ (X is any of 1 to 6) may all be different, or some or all may be the same. At least one of a to f is an integer of 1 or more, and R １ ~R ６ At least one of these is an alkoxy group.

[0012] The present disclosure can provide a photosensitive composition that can be made halogen-free, a photosensitive element, a method for forming a resist pattern, and a method for producing a printed wiring board.

[0013] Hereinafter, embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments.

[0014] In the present disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in the present disclosure, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, the upper or lower limit of a numerical range described in the present disclosure may be replaced with a value shown in an example.

[0015] Unless otherwise specified, the photosensitive composition of the present disclosure may contain one or more substances corresponding to each component.

[0016] In the present disclosure, when a photosensitive composition contains multiple substances corresponding to a certain component, the content of that component in the photosensitive composition means the total amount of the multiple substances present in the photosensitive composition, unless otherwise specified.

[0017] In the present disclosure, (meth)acrylic acid refers to at least one of acrylic acid and methacrylic acid, (meth)acrylate refers to at least one of acrylate and its corresponding methacrylate, and (meth)acryloyl group refers to at least one of acryloyl group and methacryloyl group.

[0018] In this disclosure, unless otherwise specified, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values ​​calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The GPC conditions are shown below.

[0019] Detector: L-2490 RI (manufactured by Hitachi High-Tech Corporation) Column: Gelpack GL-R440, Gelpack GL-R450, and Gelpack GL-R400M (manufactured by Resonaq Techno Service Co., Ltd.) Eluent: tetrahydrofuran Sample concentration: 5 mg / 1 mL Injection amount: 200 μL Flow rate: 2.05 mL / min Measurement temperature: 40° C. A photosensitive composition according to one embodiment of the present disclosure is a photosensitive composition comprising a binder polymer (A), a photopolymerizable compound (B), and a hexaarylbiimidazole compound (C1) that does not contain a halogen atom in its molecular structure.

[0020] A photosensitive composition according to another embodiment of the present disclosure is a photosensitive composition including a binder polymer (A), a photopolymerizable compound (B), and a hexaarylbiimidazole compound (C2) represented by the following general formula (1):

[0021]

[0022] [In general formula (1), R １ ~R ６ are each independently an alkyl group or an alkoxy group, and a to f are each independently 0 or an integer of 1 to 5. When a to f are an integer of 2 or more, a plurality of R Ｘ(X is any of 1 to 6) may all be different, or some or all may be the same. At least one of a to f is an integer of 1 or more, and R １ ~R ６ At least one of these is an alkoxy group.

[0023] In one embodiment of the photosensitive composition, a hexaarylbiimidazole compound (C1) (hereinafter sometimes referred to as "hexaarylbiimidazole compound (C1)") that does not contain a halogen atom in its molecular structure is a component that generates a hydrogen abstraction radical upon light irradiation and can function as a photopolymerization initiator. The photosensitive composition can be used, for example, in photosensitive elements such as negative resist materials. By including the hexaarylbiimidazole compound (C1) as a photopolymerization initiator, the photosensitive composition exhibits excellent photosensitivity and developability.

[0024] In one embodiment of the photosensitive composition, the hexaarylbiimidazole compound (C2) is a component that generates a hydrogen abstraction radical upon irradiation with light and can function as a photopolymerization initiator. The photosensitive composition can be used, for example, in photosensitive elements such as negative resist materials. By including the hexaarylbiimidazole compound (C2) as a photopolymerization initiator, the photosensitive composition exhibits excellent photosensitivity and developability.

[0025] [Binder polymer (A)] One type of binder polymer (A) may be used alone, or two or more types may be used in combination. From the viewpoint of halogen-free, it is preferable that the binder polymer (A) does not contain halogen atoms in its molecular structure. Here, "a binder polymer not containing halogen atoms in its molecular structure" includes not only a binder polymer whose halogen atom content is below the detection limit when actually analyzed, but also a binder polymer that theoretically does not contain halogen atoms in its molecular structure, and does not exclude, for example, a binder polymer that contains a trace amount of halogen atoms due to industrial production reasons.

[0026] The binder polymer (A) preferably has a weight-average molecular weight (Mw) of 5,000 or more, more preferably 10,000 or more, and particularly preferably 20,000 or more, since this results in a photosensitive composition with high resolution. Furthermore, the binder polymer (A) preferably has a weight-average molecular weight (Mw) of 150,000 or less, more preferably 100,000 or less, and particularly preferably 50,000 or less, since this results in a photosensitive composition with excellent developability. The weight-average molecular weight (Mw) of the binder polymer (A) may be, for example, in the range of 5,000 to 150,000. The dispersity (Mw / Mn) of the binder polymer (A) is not particularly limited, but may be, for example, 1.0 or more and 3.0 or less.

[0027] The binder polymer (A) preferably does not contain a photopolymerizable group, since this results in a photosensitive composition with excellent developability and resolution. When the photosensitive composition is used for alkaline development, the binder polymer (A) preferably has an acid group such as a carboxy group, since this results in a photosensitive composition with excellent alkaline developability. The acid value of the binder polymer (A) may be, for example, 80 mg KOH / g or more, 100 mg KOH / g or more, or 150 mg KOH / g or more. The acid value of the binder polymer (A) may be, for example, 250 mg KOH / g or less, 220 mg KOH / g or less, or 210 mg KOH / g or less.

[0028] In the present disclosure, the acid value of the binder polymer (A) is a value measured by the following method. First, 30 g of acetone is added to 1 g of the binder polymer (A) to be measured for its acid value, and the mixture is dissolved uniformly. Next, an appropriate amount of phenolphthalein as an indicator is added to the acetone solution of the binder polymer (A), and then titration is performed using a 0.1 N aqueous potassium hydroxide (KOH) solution. The acid value can be calculated from the amount of aqueous potassium hydroxide (KOH) solution required to neutralize the acetone solution of the binder polymer (A).

[0029] An example of the binder polymer (A) is an acrylic resin (A1) having an acid group (hereinafter, this may be referred to as "acrylic resin (A1)"). Examples of the acrylic resin (A1) include those containing a polymerizable monomer having an acid group, such as (meth)acrylic acid, as a constituent unit.

[0030] The acrylic resin (A1) may contain other polymerizable monomers as structural units in addition to the polymerizable monomer having an acid group. Examples of other polymerizable monomers include alkyl acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; hydroxyl group-containing (meth)acrylates such as hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate; alicyclic (meth)acrylates such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyl (meth)acrylate; aromatic ring-containing (meth)acrylates such as phenyl (meth)acrylate, benzyl (meth)acrylate, and phenoxyethyl (meth)acrylate; and styrene compounds such as styrene and α-methylstyrene. These may be used alone or in combination of two or more.

[0031] The acrylic resin (A1) may, for example, be one having a divalent group represented by the following general formula (2).

[0032]

[0033] [In formula (2), R ７ is a hydrogen atom or a methyl group.

[0034] The proportion of the divalent group represented by general formula (2) in the acrylic resin (A1) is appropriately adjusted depending on the desired acid group in the acrylic resin (A1), but may be, for example, 10% by mass or more, 15% by mass or more, or 20% by mass or more. It may also be 50% by mass or less, 40% by mass or less, or 35% by mass or less. The proportion of the divalent group represented by general formula (2) in the acrylic resin (A1) may be, for example, in the range of 10 to 50% by mass.

[0035] The acrylic resin (A1) may have, in addition to the divalent group represented by general formula (2), one or more divalent groups represented by any of the following general formulae (3) to (5):

[0036]

[0037] [In general formula (3), R ８ is a hydrogen atom or a methyl group. ９ is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a hydroxyl group, and g is 0 or an integer of 1 to 5. When g is 2 or more, multiple R ９ may all be different, or some or all may be the same.

[0038] In general formula (4), R １０ is a hydrogen atom or a methyl group. １１ is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a hydroxyl group, and h is 0 or an integer of 1 to 5. When h is 2 or more, multiple R １１ may all be different, or some or all may be the same.

[0039] R in general formula (5) １２ is a hydrogen atom or a methyl group. １３ is an alkyl group having 1 to 4 carbon atoms or a hydroxyalkyl group having 1 to 4 carbon atoms.

[0040] R in general formula (3) ９ and R in general formula (4) １１is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a hydroxyl group. Specific examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. Specific examples of the alkoxy group having 1 to 3 carbon atoms include a methoxy group, an ethoxy group, an n-propyloxy group, and an isopropyloxy group. g in general formula (3) and h in general formula (4) are 0 or an integer of 1 to 5. g and h may be, for example, 0 or 1, or may be 0.

[0041] R in general formula (5) １３ is an alkyl group having 1 to 4 carbon atoms or a hydroxyalkyl group having 1 to 4 carbon atoms. Specific examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an s-butyl group, and an isobutyl group. Specific examples of the hydroxyalkyl group having 1 to 4 carbon atoms include an alkyl group having 1 to 4 carbon atoms in which one or more hydrogen atoms have been substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, and a hydroxybutyl group.

[0042] The proportion of the divalent group represented by general formula (2) in the acrylic resin (A1) is appropriately adjusted depending on the desired acid group in the acrylic resin (A1), but may be, for example, 10% by mass or more, 15% by mass or more, or 20% by mass or more. It may also be 50% by mass or less, 40% by mass or less, or 35% by mass or less. The proportion of the divalent group represented by general formula (2) in the acrylic resin (A1) may be, for example, in the range of 10 to 50% by mass.

[0043] In the acrylic resin (A1), the proportion of the divalent group represented by general formula (3) may be, for example, 10% by mass or more, 20% by mass or more, or 35% by mass or more. It may also be 65% by mass or less, 55% by mass or less, or 50% by mass or less. In the acrylic resin (A1), the proportion of the divalent group represented by general formula (3) may be, for example, in the range of 10 to 65% by mass.

[0044] In the acrylic resin (A1), the proportion of the divalent group represented by general formula (4) may be, for example, 5% by mass or more, 10% by mass or more, or 15% by mass or more. It may also be 50% by mass or less, 40% by mass or less, or 30% by mass or less. In the acrylic resin (A1), the proportion of the divalent group represented by general formula (2) may be, for example, in the range of 5 to 50% by mass.

[0045] In the acrylic resin (A1), the proportion of the divalent group represented by general formula (5) may be, for example, 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more. It may also be 30% by mass or less, 20% by mass or less, or 15% by mass or less. In the acrylic resin (A1), the proportion of the divalent group represented by general formula (2) may be, for example, in the range of 0.1 to 30% by mass.

[0046] In the acrylic resin (A1), the total proportion of divalent groups represented by any one of general formulas (2) to (5) may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or even 100% by mass.

[0047] The proportion of the acrylic resin (A1) relative to the total amount of the binder polymer (A) may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass.

[0048] [Photopolymerizable Compound (B)] The photopolymerizable compound (B) may be used alone or in combination of two or more. From the viewpoint of halogen-free, it is preferable that the photopolymerizable compound (B) does not contain halogen atoms in its molecular structure. Here, "a compound not containing halogen atoms in its molecular structure" includes a compound whose halogen atom content is below the detection limit in actual analysis, as well as a compound that theoretically does not contain halogen atoms in its molecular structure, and does not exclude, for example, a compound that contains a trace amount of halogen atoms due to industrial production reasons.

[0049] The photopolymerizable compound (B) preferably has a molecular weight of 4,000 or less, since this results in a photosensitive composition with high sensitivity and resolution. The molecular weight of the photopolymerizable compound (B) may be 3,000 or less, or may be 2,000 or less. The molecular weight of the photopolymerizable compound (B) may be 100 or more, 200 or more, or 500 or more. The molecular weight of the photopolymerizable compound (B) may be, for example, in the range of 100 to 4,000.

[0050] Specifically, the photopolymerizable compound (B) may be a compound having a photopolymerizable group such as a (meth)acryloyl group, a vinyl group, etc. Examples of the photopolymerizable compound (B) include a monofunctional photopolymerizable compound having one photopolymerizable group in one molecule (hereinafter sometimes referred to as a "monofunctional compound (B1)"), a bifunctional photopolymerizable compound having two photopolymerizable groups in one molecule (hereinafter sometimes referred to as a "bifunctional compound (B2)"), and a polyfunctional photopolymerizable compound having three or more photopolymerizable groups in one molecule (hereinafter sometimes referred to as a "polyfunctional compound (B3)").

[0051] Examples of the monofunctional compound (B1) include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate; (meth)acrylates containing an alicyclic structure such as dicyclopentenyl (meth)acrylate and dicyclopentanyl (meth)acrylate; (meth)acrylates containing an aromatic ring structure such as benzyl (meth)acrylate and nonylphenoxy (meth)acrylate; (meth)acrylates containing a heterocyclic structure such as tetramethylpiperidyl (meth)acrylate and pentamethylpiperidyl (meth)acrylate; and (poly)alkylene oxide-modified compounds thereof; and phthalate compounds such as γ-chloro-β-hydroxyalkyl-β'-(meth)acryloyloxyalkyl phthalate and β-hydroxyalkyl-β'-(meth)acryloyloxyalkyl phthalate.

[0052] Examples of the bifunctional compound (B2) include di(meth)acrylates of aliphatic polyols and (poly)alkylene oxide-modified compounds thereof, di(meth)acrylates of bisphenols and (poly)alkylene oxide-modified compounds thereof, di(meth)acrylates of bifunctional epoxy compounds and (poly)alkylene oxide-modified compounds thereof, polyalkylene glycol di(meth)acrylates, and urethane di(meth)acrylates.

[0053] Regarding the di(meth)acrylate of an aliphatic polyol, examples of the aliphatic polyol include ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, trimethylolethane, trimethylolpropane, and glycerin.

[0054] In the di(meth)acrylate of bisphenol, the bisphenol preferably does not contain a halogen atom in the molecular structure, and examples thereof include bisphenol A, bisphenol AP, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, and bisphenol F.

[0055] Regarding the di(meth)acrylate of a difunctional epoxy compound, examples of the difunctional epoxy compound include diglycidyl ethers of biphenol and bisphenol. Examples of bisphenols include those mentioned above.

[0056] With regard to polyalkylene glycol di(meth)acrylate, examples of the alkylene oxide group in the molecular structure include ethylene oxide, propylene oxide, and butylene oxide. The polyalkylene glycol di(meth)acrylate may have multiple types of alkylene oxide groups in one molecule, and in this case, it may be a block type in which the same alkylene oxide groups are consecutive, or a random type in which multiple types of alkylene oxide groups are randomly connected. The total number of alkylene oxide groups in one molecule may be 6 or more, 10 or more, or 12 or more. It may also be 32 or less, 28 or less, or 24 or less. The total number of alkylene oxide groups in one molecule of the polyalkylene glycol di(meth)acrylate may be, for example, in the range of 6 to 32. If the number of alkylene oxide groups in one molecule is not constant due to reasons such as industrial production, the average value may be in the range of 6 to 32.

[0057] Examples of the urethane di(meth)acrylate include a urethane reaction product of a hydroxyalkyl (meth)acrylate with a diisocyanate compound and a (poly)alkylene oxide-modified compound thereof. Examples of the diisocyanate compound include hexamethylene diisocyanate, isophorone diisocyanate, and toluene diisocyanate.

[0058] Examples of the polyfunctional compound (B3) include poly(meth)acrylates of tri- or higher functional aliphatic polyols and (poly)alkylene oxide-modified compounds thereof, and poly(meth)acrylates of tri- or higher functional epoxy compounds and (poly)alkylene oxide-modified compounds thereof.

[0059] Regarding the poly(meth)acrylate of a trifunctional or higher aliphatic polyol, examples of the trifunctional or higher aliphatic polyol include trimethylolethane, trimethylolpropane, glycerin, tetramethylolmethane, pentaerythritol, dipentaerythritol, etc. Specific examples of these poly(meth)acrylates include trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc.

[0060] With respect to the (poly)alkylene oxide-modified compounds in compounds (B1), (B2), and (B3), examples of the alkylene oxide group include ethylene oxide, propylene oxide, and butylene oxide. The (poly)alkylene oxide-modified compound may have multiple types of alkylene oxide groups in one molecule. The polyalkylene oxide group may be a block type in which the same alkylene oxide group is consecutive, or a random type in which multiple types of alkylene oxide groups are randomly linked. In the (poly)alkylene oxide-modified compound, the total number of alkylene oxide groups in one molecule may be in the range of 2 to 20. If the number of alkylene oxide groups in one molecule is not constant due to reasons such as industrial production, the average value may be in the range of 2 to 20.

[0061] Among these photopolymerizable compounds (B), it is preferable to include at least one selected from the group consisting of a bifunctional compound (B2) and a polyfunctional compound (B3), since this results in a photosensitive composition with high sensitivity and resolution. The total proportion of the bifunctional compound (B2) and the polyfunctional compound (B3) to the entire photopolymerizable compound (B) may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or even 100% by mass.

[0062] Furthermore, since a photosensitive composition having an excellent balance between sensitivity, resolution, and substrate adhesion can be obtained, the photopolymerizable compound (B) preferably contains a bifunctional compound (B2). The proportion of the bifunctional compound (B2) relative to the total amount of the photopolymerizable compound (B) may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or even 100% by mass.

[0063] Among the bifunctional compounds (B2), particularly preferred are (poly)alkylene oxide-modified compounds of bisphenol di(meth)acrylate (hereinafter, this may be referred to as "bifunctional compound (B2-1)") and polyalkylene glycol di(meth)acrylate (hereinafter, this may be referred to as "bifunctional compound (B2-2)"). The total proportion of the bifunctional compounds (B2-1) and (B2-2) relative to the entire photopolymerizable compound (B) may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or even 100% by mass.

[0064] The mass ratio of the bifunctional compound (B2-1) to the bifunctional compound (B2-2) may be such that the proportion of the bifunctional compound (B2-1) relative to the total of the two is 50 mass% or more, 70 mass% or more, or 85 mass% or more. It may also be 99.5 mass% or less, 99 mass% or less, or 97 mass% or less. The proportion of the bifunctional compound (B2-1) relative to the total of the bifunctional compound (B2-1) and the bifunctional compound (B2-2) may be, for example, in the range of 50 to 99.5 mass%.

[0065] Examples of the bifunctional compound (B2-1) include compounds represented by the following general formula (6).

[0066]

[0067] [R in general formula (6)] １４ are each independently a hydrogen atom, a methyl group, an ethyl group, or a phenyl group. １５ , R １６ are each independently an alkylene group having 2 to 4 carbon atoms. １７are each independently a hydrogen atom or a methyl group; and i and j are each an integer of 1 or greater.

[0068] R in general formula (6) １５ , R １６ are each independently an alkylene group having 2 to 4 carbon atoms, specifically an ethylene group, a propylene group, or a butylene group. When i and j are each 2 or more, a plurality of R １５ , R １６ may all be different, or some or all may be the same.

[0069] In general formula (6), i and j are each an integer of 1 or more. i and j may be in the range of 1 to 12. When the number of alkylene oxide groups in one molecule is not constant due to reasons such as industrial production, the average value may be in the range of 1 to 12. Furthermore, the sum of i and j may be in the range of 2 to 20. When the number of alkylene oxide groups in one molecule is not constant due to reasons such as industrial production, the average value may be in the range of 2 to 20.

[0070] As the bifunctional compound (B2-1), multiple types of compounds having different total numbers of alkylene oxide groups per molecule may be used in combination. Specifically, a bifunctional compound (B2-1) having a total number (or average value) of alkylene oxide groups per molecule in the range of 2 to 6 may be used in combination with a bifunctional compound (B2-1) having a total number (or average value) of alkylene oxide groups per molecule in the range of 8 to 14. The mass ratio of the two may be, for example, such that the proportion of the number (or average value) of alkylene oxide groups per molecule in the range of 2 to 6 relative to the total mass of the two may be 5% by mass or more, 10% by mass or more, or 15% by mass or more. It may also be 55% by mass or less, 45% by mass or less, or 35% by mass or less. This value may be, for example, in the range of 5 to 55% by mass.

[0071] Examples of the bifunctional compound (B2-2) include compounds represented by the following general formula (7).

[0072]

[0073] [In the general formula (7), k is an integer of 2 or more. １８ are each independently an alkylene group having 2 to 4 carbon atoms. １９ are each independently a hydrogen atom or a methyl group.

[0074] In general formula (7), k is an integer of 2 or more. k may be 6 or more, 10 or more, or 12 or more. It may also be 32 or less, 28 or less, or 24 or less. The value of k may be, for example, in the range of 6 to 32. When the number of alkylene oxide groups in one molecule is not constant due to the convenience of industrial production or the like, the average value may be in the range of 6 to 32.

[0075] Multiple R's in the formula １８ are each independently an alkylene group having 2 to 4 carbon atoms, specifically an ethylene group, a propylene group, or a butylene group. As described above, the bifunctional compound (B2-2) may have multiple types of alkylene oxide groups in one molecule, and in this case, they may be of a block type in which the same alkylene oxide groups are consecutive, or of a random type in which multiple types of alkylene oxide groups are randomly linked. The bifunctional compound (B2-2) may be, for example, a compound represented by the following general formula (7-1):

[0076]

[0077] [In general formula (7-1), l, m, and n each independently represent an integer of 1 or more. R １９ are each independently a hydrogen atom or a methyl group.

[0078] In general formula (7-1), l, m, and n each independently represent an integer of 1 or greater. For example, l, m, and n may each independently range from 2 to 20. The sum of l and n may range from 4 to 12, or may range from 4 to 8. m may range from 8 to 16. When the number of alkylene oxide groups in one molecule is not constant due to reasons such as industrial production, each value may be an average value.

[0079] [Hexaarylbiimidazole Compounds (C1) and (C2)] Regarding the hexaarylbiimidazole compound (C1), the hexaarylbiimidazole is a compound having a structure in which, in a biimidazole structure in which two imidazole rings are bonded, aryl groups are bonded to the carbon atoms at the 2nd, 4th, and 5th positions of the imidazole.

[0080] In the hexaarylbiimidazole compound (C1), the two imidazole rings can be bonded, for example, via the nitrogen atom at position 1 and the carbon atom at position 2. Specifically, the nitrogen atoms at positions 1 of both imidazole rings may be bonded to each other, or the nitrogen atom at position 1 of one imidazole ring may be bonded to the carbon atom at position 2 of the other imidazole ring.

[0081] The specific structure of the hexaarylbiimidazole compound (C1) is not particularly limited as long as it does not contain a halogen atom in its molecular structure. Among these, it is preferable that the hexaarylbiimidazole compound (C1) has an alkoxy group in its molecular structure, since this provides a photosensitive composition with high photosensitivity and excellent resolution when used in a resist material. The number of alkoxy groups in one molecule is not particularly limited, but may be, for example, 6 or less, or 3 or less.

[0082] The substitution position of the alkoxy group on each aryl group is not particularly limited, and may be any of the ortho-, meta-, and para-positions relative to the bonding position to the imidazole ring. In particular, it is preferable that the alkoxy group be substituted at the ortho-position relative to the bonding position to the imidazole ring, since this will result in the hexaarylbiimidazole compound (C1) having excellent solvent solubility.

[0083] The number of carbon atoms in the alkoxy group of the hexaarylbiimidazole compound (C1) is preferably in the range of 2 to 10, since this not only results in a photosensitive composition with even more excellent photosensitivity and resolution, but also in the hexaarylbiimidazole compound (C1) having excellent solvent solubility. Furthermore, a range of 3 to 8 is more preferable, since this achieves an even better balance between the photosensitivity and resolution of the photosensitive composition and the solvent solubility of the hexaarylbiimidazole compound (C1). The carbon chain of the alkoxy group may be linear or may have a branched structure. Of these, a linear structure is preferred, since this results in the hexaarylbiimidazole compound (C1) having even more excellent solvent solubility. Specific examples of the alkoxy group include an n-propyloxy group, an n-butyloxy group, an n-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, and an n-octyloxy group.

[0084] In one embodiment of the present disclosure, the photosensitive composition contains a hexaarylbiimidazole compound (C2) represented by the following general formula (1):

[0085]

[0086] [In general formula (1), R １ ~R ６ are each independently an alkyl group or an alkoxy group, and a to f are each independently 0 or an integer of 1 to 5. When a to f are an integer of 2 or more, a plurality of R Ｘ (X is any of 1 to 6) may all be different, or some or all may be the same. At least one of a to f is an integer of 1 or more, and R １ ~R ６ At least one of the groups is an alkoxy group.] In general formula (1), the two imidazole rings can be bonded, for example, via the nitrogen atom at position 1 and the carbon atom at position 2. Specifically, the two imidazole rings may be bonded to each other via the nitrogen atoms at position 1, or via the nitrogen atom at position 1 of one imidazole ring and the carbon atom at position 2 of the other imidazole ring. The position numbers of the imidazole rings are as follows:

[0087]

[0088] R in general formula (1) １ ~R ６ are each independently an alkyl group or an alkoxy group. The number of carbon atoms in the alkyl group is preferably in the range of 2 to 10, since this will result in the hexaarylbiimidazole compound (C2) having excellent solvent solubility. The alkyl group may be linear or may have a branched structure. Of these, a linear alkyl group is preferred, since this will result in the hexaarylbiimidazole compound (C2) having even more excellent solvent solubility. Specific examples of the alkyl group include an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group.

[0089] The number of carbon atoms in the alkoxy group is preferably in the range of 2 to 10, since this will result in the hexaarylbiimidazole compound (C2) having excellent solvent solubility. Furthermore, a range of 3 to 8 is more preferable, since this will result in an even better balance between the photosensitivity and resolution of the photosensitive composition and the solvent solubility of the hexaarylbiimidazole compound (C2). The carbon chain of the alkoxy group may be linear or may have a branched structure. Of these, a linear structure is preferable, since this will result in the hexaarylbiimidazole compound (C2) having even better solvent solubility. Specific examples of the alkoxy group include an n-propyloxy group, an n-butyloxy group, an n-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, and an n-octyloxy group.

[0090] R present in general formula (1) １ ~R ６ At least one of the R groups in the formula is an alkoxy group. １ ~R ６ may all be alkoxy groups. The number of alkoxy groups in one molecule is not particularly limited, but may be, for example, 6 or less, or 3 or less. Of these, the range of 1 to 3 is preferred, and 2 is particularly preferred.

[0091] R on each aryl group １ ~R６ The substitution position of R is not particularly limited, and may be any of the ortho-, meta-, and para-positions relative to the bonding position with the imidazole ring. Among these, in order to give the hexaarylbiimidazole compound (C2) excellent solvent solubility, it is preferable to have R at the ortho-position relative to the bonding position with the imidazole ring. １ ~R ６ is preferably substituted.

[0092] In the general formula (1), a to f are each independently 0 or an integer of 1 to 5. In particular, a to f are each independently preferably 0 or 1, since this gives the hexaarylbiimidazole compound (C2) excellent solvent solubility. Furthermore, it is more preferable that a and d are each 1, and b, c, e, and f are each 0. In this case, when there is one R １ and R ４ is preferably an alkoxy group.

[0093] The hexaarylbiimidazole compound (C2) may be, for example, a compound represented by the following general formula (1-1):

[0094]

[0095] [In general formula (1-1), R １ ~R ６ and b, c, e, and f have the same meanings as in general formula (1).

[0096] [Photosensitive Composition] The photosensitive composition of one embodiment contains a binder polymer (A), a photopolymerizable compound (B), and a hexaarylbiimidazole compound (C1) or a hexaarylbiimidazole compound (C2) (hereinafter, these may be collectively referred to as "hexaarylbiimidazole compound (C)").

[0097] The ratio of the binder polymer (A) to the photopolymerizable compound (B) can be appropriately adjusted depending on the desired photosensitivity, developability, resolution, etc., when used in a photosensitive element, for example. For example, the ratio of the binder polymer (A) to the total mass of the binder polymer (A) and the photopolymerizable compound (B) may be 15% by mass or more, 20% by mass or more, or 30% by mass or more. It may also be 60% by mass or less, 50% by mass or less, or 45% by mass or less. The ratio of the binder polymer (A) to the total mass of the binder polymer (A) and the photopolymerizable compound (B) may be, for example, in the range of 15 to 60% by mass.

[0098] The amount of the hexaarylbiimidazole compound (C) added may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, based on the total mass of the binder polymer (A) and the photopolymerizable compound (B). It may also be 15% by mass or less, 10% by mass or less, or 7% by mass or less. The amount of the hexaarylbiimidazole compound (C) added may be, for example, in the range of 0.1 to 15% by mass, based on the total mass of the binder polymer (A) and the photopolymerizable compound (B).

[0099] The photosensitive composition may contain other components in addition to the binder polymer (A), the photopolymerizable compound (B), and the hexaarylbiimidazole compound (C). Examples of other components include a photopolymerization initiator (D) other than the hexaarylbiimidazole compound (C), a hydrogen donor (E), a photosensitizer (F), an organic solvent (G), an adhesion aid, a leveling agent, a polymerization inhibitor, a dye, a plasticizer, an antifoaming agent, a flame retardant, and a release promoter.

[0100] Regarding the other photopolymerization initiator (D) (hereinafter, this may be referred to as "photopolymerization initiator (D)"), as described above, the hexaarylbiimidazole compound (C) is a component that generates a hydrogen abstraction radical upon irradiation with light and functions as a photopolymerization initiator, but the photosensitive composition may further contain a photopolymerization initiator (D). The photopolymerization initiator (D) may be used alone or in combination of two or more types. Specific examples of the photopolymerization initiator (D) include hydrogen abstraction radical generators such as benzophenone compounds, thioxanthone compounds, fluorenone compounds, and acridine compounds; and intramolecular cleavage radical generators such as benzyl ketal compounds, α-aminoalkylphenone compounds, α-hydroxyalkylphenone compounds, α-hydroxyacetophenone compounds, and acylphosphine oxide compounds.

[0101] The ratio of the hexaarylbiimidazole compound (C) to the total mass of the hexaarylbiimidazole compound (C) and the photopolymerization initiator (D) may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or even 100% by mass. The total amount of the hexaarylbiimidazole compound (C) and the photopolymerization initiator (D) added may be 0.1% by mass or more, 0.5% by mass or more, or even 1% by mass or more, relative to the total mass of the binder polymer (A) and the photopolymerizable compound (B). The total amount of the hexaarylbiimidazole compound (C) and the photopolymerization initiator (D) added may be, for example, in the range of 0.1 to 15% by mass, relative to the total mass of the binder polymer (A) and the photopolymerizable compound (B).

[0102] The hydrogen donor (E) is a component that donates hydrogen to a hydrogen abstraction radical generator such as the hexaarylbiimidazole compound (C), and the newly generated radical can function as a polymerization initiator. The hydrogen donor (E) may be used alone or in combination of two or more. Specific examples of the hydrogen donor (E) include bis[4-(dimethylamino)phenyl]methane, bis[4-(diethylamino)phenyl]methane, and tris[4-(dimethylamino)phenyl]methane (also known as leucocrystal violet). Among these, tris[4-(dimethylamino)phenyl]methane is preferred. The amount of the hydrogen donor (E) added may be 0.05% by mass or more, 0.1% by mass or more, or 0.3% by mass or more, based on the total mass of the binder polymer (A) and the photopolymerizable compound (B). It may also be 5% by mass or less, 3% by mass or less, or 1% by mass or less. The amount of the hydrogen donor (E) added may be, for example, in the range of 0.05 to 5% by mass based on the total mass of the binder polymer (A) and the photopolymerizable compound (B).

[0103] Examples of the photosensitizer (F) include anthracene compounds, benzophenone compounds, pyrazoline compounds, coumarin compounds, xanthone compounds, thioxanthone compounds, oxazole compounds, benzoxazole compounds, thiazole compounds, benzothiazole compounds, triazole compounds, triazine compounds, thiophene compounds, naphthalimide compounds, triarylamine compounds, and aminoacridine compounds. The amount of the photosensitizer (F) added may be 0.005% by mass or more, 0.01% by mass or more, or 0.05% by mass or more, based on the total mass of the binder polymer (A) and the photopolymerizable compound (B). It may also be 5% by mass or less, 3% by mass or less, or 1% by mass or less. The amount of the photosensitizer (F) added may be, for example, in the range of 0.005 to 5% by mass, based on the total mass of the binder polymer (A) and the photopolymerizable compound (B).

[0104] The organic solvent (G) is a component used primarily to adjust the viscosity of the photosensitive composition and improve workability during the production of the photosensitive element. The organic solvent (G) may be used singly or in combination of two or more. The proportion of the organic solvent (G) in the photosensitive composition is appropriately adjusted depending on the desired viscosity, the desired film thickness of the photosensitive composition layer in the photosensitive element, and the like, and may be, for example, 20% by mass or more, 30% by mass or more, or 40% by mass or more. It may also be 90% by mass or less, 80% by mass or less, or 70% by mass or less. The proportion of the organic solvent (G) in the photosensitive composition may be, for example, in the range of 20 to 90% by mass.

[0105] Specific examples of the organic solvent (G) include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-cymene; aliphatic hydrocarbons such as hexane and heptane; cyclic alkanes such as methylcyclohexane; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; alcohols such as methanol and ethanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, and γ-butyrolactone; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, and propylene glycol dimethyl ether; glycol ether acetates such as propylene glycol 1-monomethyl ether 2-acetate; carbonate esters such as ethylene carbonate and propylene carbonate; and amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone (NMP). As described above, among the hexaarylbiimidazole compounds (C), those having an alkoxy group in the molecular structure are characterized by excellent solvent solubility, and exhibit high solubility even when an aromatic hydrocarbon such as toluene or a ketone such as cyclopentanone is used as the organic solvent (G).

[0106] The photosensitive composition may be used as a dry film photosensitive element or as a liquid negative resist material.

[0107] [Photosensitive Element] The photosensitive element of one embodiment comprises a support and a photosensitive composition layer containing a photosensitive composition formed on the support. Examples of the support include support films such as polyester films such as polyethylene terephthalate, polyolefin films such as polypropylene and polyethylene, and semiconductor wafers such as silicon wafers, sapphire wafers, and compound semiconductor wafers. The thickness of the support film may be, for example, in the range of 1 to 100 μm. The thickness of the semiconductor wafer may be, for example, in the range of 0.1 to 2 mm.

[0108] The photosensitive composition layer contains a photosensitive composition. The photosensitive composition layer can be formed, for example, by coating the photosensitive composition on a support to a desired thickness. When the photosensitive composition contains an organic solvent (G), it is preferable to volatilize the organic solvent (G) so that the content of the organic solvent (G) in the photosensitive composition layer is 2% by mass or less. The drying temperature may be, for example, in the range of 70 to 150°C. The drying time may be in the range of 5 to 30 minutes. The photosensitive composition can be applied using, for example, a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, a bar coater, or the like. The preferred thickness of the photosensitive composition layer varies depending on the application of the photosensitive element, but may be, for example, in the range of 1 to 100 μm.

[0109] The photosensitive element may further have a protective film on the surface of the photosensitive composition layer. Examples of the protective film include polyester films such as polyethylene terephthalate, and polyolefin films such as polypropylene and polyethylene. The thickness of the protective film may be in the range of, for example, 1 to 100 μm.

[0110] The photosensitive element may have an intermediate layer between the support and the photosensitive composition layer, such as a layer containing a water-soluble resin such as a polyvinyl alcohol resin, an adhesive layer, a light-absorbing layer, or a gas barrier layer.

[0111] When the support is a support film, the photosensitive element may be in the form of a sheet or wound into a roll. When wound into a roll, the support film may be wound on the outside.

[0112] [Method for forming a resist pattern] A method for forming a resist pattern in one embodiment includes a laminating step of laminating a photosensitive composition layer containing a photosensitive composition on a circuit-forming substrate, an exposing step of irradiating predetermined portions of the photosensitive composition layer with actinic rays to photocure the exposed portions, and a developing step of removing portions of the photosensitive composition layer other than the exposed portions from the circuit-forming substrate on which the photosensitive composition layer has been laminated.

[0113] Examples of the circuit-forming substrate include a substrate having an insulating layer and a conductor layer formed on the insulating layer, a metal substrate for manufacturing a metal mask, a die pad (substrate for a lead frame) such as an alloy substrate, etc. The circuit-forming substrate may be multilayered and have wiring formed therein, or may have small-diameter through holes.

[0114] The lamination step is a step of laminating a photosensitive composition layer on a circuit-forming substrate. The photosensitive composition layer may be laminated by a method of directly applying the photosensitive composition onto the circuit-forming substrate and drying the organic solvent (G) as necessary. Alternatively, the photosensitive composition layer may be laminated by a method of using a photosensitive element whose support is a support film and pressing the photosensitive composition layer of the photosensitive element onto the circuit-forming substrate while heating. When the photosensitive element has a protective film, the protective film is removed and then the photosensitive composition layer is heated and pressed. When a photosensitive element whose support is a support film is used, the lamination step is preferably carried out under reduced pressure conditions from the viewpoint of adhesion and followability. The heating temperature during pressing may be in the range of 70 to 130°C. In order to further improve the lamination properties of the photosensitive composition layer, the circuit-forming substrate may be preheated. The pressure during pressing may be, for example, 0.1 to 1.0 MPa (1 to 10 kgf / cm２ ) range.

[0115] Examples of the exposure step include a method of irradiating actinic rays through a pattern called artwork (mask exposure method), a projection exposure method, a laser direct writing exposure method, a DLP exposure method, etc. When a photosensitive element whose support is a support film is used in the lamination step, if the support film present on the photosensitive composition layer transmits actinic rays, actinic rays can be irradiated through the support film, and if the support film is light-shielding, the support film is removed before irradiating the photosensitive composition layer with actinic rays.

[0116] The light source for the actinic rays can be any known light source, including, for example, those that effectively emit ultraviolet light, visible light, etc., such as carbon arc lamps, mercury vapor arc lamps, high-pressure mercury lamps, xenon lamps, gas lasers such as argon lasers, solid-state lasers such as YAG lasers, and semiconductor lasers. The wavelength of the actinic rays may be within the range of 340 nm to 430 nm.

[0117] In the developing step, if a support film is present on the photosensitive composition layer, the support film is removed before the developing step. The developing method is roughly divided into wet development and dry development, and wet development is widely used.

[0118] Examples of developers used in wet development include alkaline aqueous solutions, water-based developers, and organic solvent-based developers, and a developer appropriate for the photosensitive composition is selected and used. Development can be carried out by known methods, such as dipping, bathing, spraying, swinging immersion, brushing, and scraping. From the viewpoint of improving resolution, a high-pressure spraying method is preferably used. Furthermore, two or more developing methods may be used in combination, if necessary.

[0119] Examples of alkaline aqueous solutions include aqueous solutions of alkali hydroxides such as hydroxides of lithium, sodium, or potassium; alkali carbonates such as carbonates or bicarbonates of lithium, sodium, potassium, or ammonium; alkali metal phosphates such as potassium phosphate and sodium phosphate; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diaminopropanol-2, morpholine, and the like.

[0120] Examples of preferred alkaline aqueous solutions include a dilute solution of 0.1 to 5% by mass sodium carbonate, a dilute solution of 0.1 to 5% by mass potassium carbonate, a dilute solution of 0.1 to 5% by mass sodium hydroxide, and a dilute solution of 0.1 to 5% by mass sodium tetraborate (borax). The pH of the alkaline aqueous solution is preferably in the range of 9 to 11. The temperature of the alkaline aqueous solution may be adjusted according to the developability of the photosensitive composition layer. The alkaline aqueous solution may also contain a surfactant, an antifoaming agent, a small amount of an organic solvent to promote development, and the like.

[0121] Examples of organic solvent-based developers include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, γ-butyrolactone, etc. To prevent ignition, it is preferable to add water to these organic solvent-based developers in an amount of 1 to 20% by mass.

[0122] After the development step, the resist pattern may be further hardened by heating or exposure, if necessary. The heating temperature may be in the range of 60 to 250° C. The light dose during exposure is 0.2 to 10 J / cm. ２ may be in the range of

[0123] [Method for Manufacturing a Printed Wiring Board] A method for manufacturing a printed wiring board according to one embodiment includes a step of forming a conductor pattern by etching or plating a circuit-forming substrate on which a resist pattern has been formed by the resist pattern forming method described above.

[0124] The etching and plating of the circuit-forming substrate is performed on the conductor layer of the circuit-forming substrate using the formed resist pattern as a mask. Examples of etching solutions include cupric chloride solution, ferric chloride solution, alkaline etching solution, and hydrogen peroxide etching solution. Examples of plating methods include copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-throw solder plating, Watts bath (nickel sulfate-nickel chloride) plating, nickel plating such as nickel sulfamate, and gold plating such as hard gold plating and soft gold plating.

[0125] After forming a conductive pattern by etching or plating, the resist pattern on the substrate may be removed. The resist pattern can be removed, for example, with an alkaline aqueous solution that is stronger than the alkaline aqueous solution used for development. Examples of strong alkaline aqueous solutions include a 1 to 10 mass % sodium hydroxide aqueous solution and a 1 to 10 mass % potassium hydroxide aqueous solution. Examples of the stripping method include an immersion method and a spray method, and the immersion method and the spray method may be used alone or in combination. When the resist pattern is removed after plating, the conductive layer that was covered with the resist pattern may be further etched to form a conductive pattern.

[0126] Examples of embodiments are listed below. The present invention is not limited to the following embodiments. <1> A photosensitive composition comprising a binder polymer (A), a photopolymerizable compound (B), and a hexaarylbiimidazole compound (C1) that does not contain a halogen atom in its molecular structure. <2> The photosensitive composition according to <1> above, wherein the hexaarylbiimidazole compound (C1) has an alkoxy group in its molecular structure. <3> The photosensitive composition according to <1> or <2> above, wherein the alkoxy group has 2 to 8 carbon atoms. <4> A photosensitive composition comprising a binder polymer (A), a photopolymerizable compound (B), and a hexaarylbiimidazole compound (C2) represented by the following general formula (1):

[0127]

[0128] [In general formula (1), R１ ~R ６ are each independently an alkyl group or an alkoxy group, and a to f are each independently 0 or an integer of 1 to 5. When a to f are an integer of 2 or more, a plurality of R Ｘ (X is any of 1 to 6) may all be different, or some or all may be the same. At least one of a to f is an integer of 1 or more, and R １ ~R ６ wherein at least one is an alkoxy group.] <5> The photosensitive composition according to any one of <1> to <4>, containing toluene as an organic solvent. <6> The photosensitive composition according to any one of <1> to <5>, containing cyclopentanone as an organic solvent. <7> A photosensitive element comprising a support and a photosensitive composition layer formed on the support, the photosensitive composition layer containing the photosensitive composition according to any one of <1> to <6>. <8> A method for forming a resist pattern, comprising: a laminating step of laminating a photosensitive composition layer containing the photosensitive composition according to any one of <1> to <6> on a circuit-forming substrate; an exposing step of irradiating predetermined portions of the photosensitive composition layer with actinic light rays to photocure the exposed portions; and a developing step of removing portions of the photosensitive composition layer other than the exposed portions from the circuit-forming substrate on which the photosensitive composition layer has been laminated. <9> A method for producing a printed wiring board, comprising a step of etching or plating a circuit-forming substrate on which a resist pattern has been formed by the resist pattern forming method according to <8>, to form a conductor pattern.

[0129] The present invention will be described in more detail below with reference to examples, but is not limited to these examples. Measurement method for weight average molecular weight (Mw) and number average molecular weight (Mn) The weight average molecular weight and number average molecular weight were calculated by gel permeation chromatography (GPC) using a calibration curve using standard polystyrene. The GPC conditions are shown below.

[0130] Detector: L-2490 RI (Hitachi High-Tech Corporation) Column: Gelpack GL-R440, Gelpack GL-R450, and Gelpack GL-R400M (Resonac Technoservice Co., Ltd.) Eluent: tetrahydrofuran Sample concentration: 5 mg / 1 mL Injection amount: 200 μL Flow rate: 2.05 mL / min Measurement temperature: 40° C. Examples 1 to 5 and Comparative Example 1 [Production of Photosensitive Composition] Photosensitive compositions were produced by blending and mixing the components in the proportions shown in Table 1 below. Details of each component in Table 1 are as follows.

[0131] Binder polymer (A-1): a 47% by mass solution of acrylic resin containing 45% by mass of styrene, 23% by mass of benzyl methacrylate, 27% by mass of methacrylic acid, and 5% by mass of methyl methacrylate. The solvent was methylpropylene glycol / toluene, and the weight average molecular weight (Mw) of the acrylic resin was 51,000. Photopolymerizable compound (B-1): "FA-321M" manufactured by Resonac Co., Ltd., a polyethylene oxide-modified compound of bisphenol A di(meth)acrylate, the average total number of ethylene oxide groups per molecule was 10. Photopolymerizable compound (B-2): "NK Ester BPE-200" manufactured by Shin-Nakamura Chemical Co., Ltd., a polyethylene oxide-modified compound of bisphenol A di(meth)acrylate, the average total number of ethylene oxide groups per molecule was 4. Photopolymerizable compound (B-3): "FA-024M" manufactured by Resonac Co., Ltd., a polyalkylene glycol di(meth)acrylate represented by the following general formula (7-2), the average value of the sum of l and n was 6, and the average value of m was 12.

[0132]

[0133] Hexaarylbiimidazole compound (C-1): a compound represented by the following general formula (1-2): ２０ is an n-propyloxy group Hexaarylbiimidazole compound (C-2): a compound represented by the following general formula (1-2), in which R ２０ is an n-butyloxy group Hexaarylbiimidazole compound (C-3): a compound represented by the following general formula (1-2), in which R ２０is an n-pentyloxy group Hexaarylbiimidazole compound (C-4): a compound represented by the following general formula (1-2), in which R ２０ is an n-hexyloxy group Hexaarylbiimidazole compound (C-5): a compound represented by the following general formula (1-2), in which R ２０ is an n-octyloxy group Comparative hexaarylbiimidazole compound: a compound represented by the following general formula (1-2): ２０ Compounds in which is a chloro group

[0134]

[0135] Hydrogen donor: Leuco Crystal Violet (tris[4-(dimethylamino)phenyl]methane) manufactured by Yamada Chemical Co., Ltd. Sensitizer: 9,10-dibutoxyanthracene manufactured by Kawasaki Chemical Industries, Ltd. Adhesion aid: "XIAMETER OFS-6030 Silane" manufactured by The Dow Chemical Company, methacryloxypropyltrimethoxysilane Leveling agent: "DOWSIL 8032 Additive" manufactured by The Dow Chemical Company, polyether-modified silicone Polymerization inhibitor: "TBC-5P" manufactured by DIC Corporation, tert-butylcatechol

[0136]

[0137] [Production of Photosensitive Element] The photosensitive composition obtained above was coated on a support (*1). The coating was dried for 5 minutes in a hot air convection dryer at 90°C to form a photosensitive composition layer having a film thickness of approximately 6 μm after drying. Subsequently, a PET film (*2) was pressed onto the photosensitive composition layer as a protective layer using a heat roll at 110°C to obtain a laminate. The pressing was performed under conditions of a pressure of 0.4 MPa and a roll speed of 1.0 m / min.

[0138] Support (*1): "6-inch bare wafer" manufactured by Advantec Co., Ltd., a silicon wafer with a thickness of approximately 610 μm PET film (*2): "FB-40" manufactured by Toray Industries, Inc.

[0139] [Evaluation of Photosensitive Composition] Using glass chrome type phototools 1 (Line type) and 2 (Space type), the photosensitive element was irradiated with active energy rays through the PET film to expose the photosensitive composition layer. After exposure, the PET film was peeled off to expose the photosensitive composition layer, which was then developed using a 1% by mass aqueous sodium carbonate solution at 30°C.

[0140] The irradiation dose of active energy rays was 110 mJ / cm ２ to 10 mJ / cm ２ The x value was increased by 1 / 2 increments, and the minimum value of x at which a clear resist pattern was obtained at each dose was taken as the resolution.

[0141] The exposure dose (mJ / cm) was measured for each of the cases where photo tool 1 (Line type) and photo tool 2 (Space type). ２ The relationship between the exposure dose and the resolution (μm) was plotted on an xy coordinate, and the intersection of each approximation curve was taken as the intersection exposure dose.

[0142] Table 2 shows the intersection exposure dose and the resolution when irradiated with the intersection exposure dose for each example and comparative example.

[0143] The smaller the intersection exposure amount and the smaller the resolution value, the more excellent the photosensitivity, resolution and developability of the photosensitive composition.

[0144] Phototool 1 (Line type): Line width / Space width = x / 4x, where x is 1 μm to 10 μm in 1 μm increments. Phototool 2 (Space type): Line width / Space width = 4x / x, where x is 1 μm to 10 μm in 1 μm increments. Actinic energy ray irradiation conditions: A projection exposure apparatus using a Canon Inc. "FPA-3000iw" ultra-high pressure mercury lamp (365 nm) as a light source was used. The focus position was set at a depth of 19 μm from the surface of the support film (around the center of the film thickness of the photosensitive composition layer).

[0145]

[0146] As shown in Table 2, the photosensitive compositions of Examples 1 to 5 had smaller intersection exposure amounts and smaller resolution values ​​than the photosensitive composition of Comparative Example 1, and therefore can be said to be photosensitive compositions excellent in photosensitivity, resolution, and developability.

[0147] [Evaluation of Solvent Solubility of Photosensitive Composition] For the photosensitive compositions of Examples 1 to 5, 90 g of cyclopentanone was replaced with 90 g of the following two mixed solvents, and the compositions were stirred to evaluate solubility. Those that dissolved were designated A, and those that remained undissolved were designated B. The results are shown in Table 3. Mixed solvent 1: Acetone / toluene / methanol mixed in a mass ratio of 5 / 9 / 5 Mixed solvent 2: Acetone / cyclopentanone / methanol mixed in a mass ratio of 5 / 9 / 5

[0148]

Claims

1. A photosensitive composition comprising a binder polymer (A), a photopolymerizable compound (B), and a hexaarylbiimidazole compound (C1) that does not contain a halogen atom in its molecular structure.

2. The photosensitive composition according to claim 1, wherein the hexaarylbiimidazole compound (C1) has an alkoxy group in its molecular structure.

3. The photosensitive composition according to claim 2, wherein the alkoxy group has 2 to 10 carbon atoms.

4. A photosensitive composition comprising a binder polymer (A), a photopolymerizable compound (B), and a hexaarylbiimidazole compound (C2) represented by the following general formula (1). [In general formula (1), R １ to R ６ are each independently an alkyl group or an alkoxy group, and a to f are each independently 0 or an integer of 1 to 5. When a to f are integers of 2 or more, a plurality of R Ｘ (X is any one of 1 to 6) may all be different, or some or all may be the same. At least one of a to f is an integer of 1 or more, and among R １ to R ６ present in the formula, at least one is an alkoxy group. ] 5. The photosensitive composition according to any one of claims 1 to 4, comprising toluene as an organic solvent.

6. The photosensitive composition according to any one of claims 1 to 4, comprising cyclopentanone as an organic solvent.

7. A photosensitive element comprising a support and a photosensitive composition layer formed on the support and containing the photosensitive composition according to any one of claims 1 to 4.

8. A method for forming a resist pattern, comprising a laminating step of laminating a photosensitive composition layer containing the photosensitive composition according to any one of claims 1 to 4 on a circuit formation substrate, an exposure step of irradiating a predetermined portion of the photosensitive composition layer with actinic rays to photocure the exposed portion, and a developing step of removing portions other than the exposed portion of the photosensitive composition layer from the circuit formation substrate on which the photosensitive composition layer is laminated.

9. A method for manufacturing a printed wiring board, comprising a step of forming a conductor pattern by etching or plating a circuit formation substrate on which a resist pattern is formed by the method for forming a resist pattern according to claim 8.

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