Photosensitive resin composition, photosensitive element, method for producing wiring substrate, and photosensitive element roll

Abstract

A photosensitive resin composition comprising a binder polymer having a structural unit based on benzyl (meth)acrylate, a photopolymerizable compound, a photopolymerization initiator, and a coumarin-based sensitizer.

Description

Technology Field

[0001] The present disclosure relates to a photosensitive resin composition, a photosensitive element, a method for manufacturing a wiring substrate, and a photosensitive element roll. Background Technology

[0002] In the manufacture of wiring boards, a resist pattern is formed to obtain desired wiring. Photosensitive resin compositions are widely used for forming resist patterns. Recently, the Modified Semi-Additive Process (MSAP) has attracted attention as a method capable of forming fine wiring. In this method, to form fine wiring, it is necessary to form the resist pattern with better precision than conventional methods.

[0003] In order to form a resist pattern with good precision, a photosensitizer is generally added to the photosensitive resin composition. As photosensitizers, anthracene derivatives such as 9,10-dibutoxycyanthracene (DBA) are known (see, for example, Patent Document 1). Prior art literature

[0004] Patent Document 1: International Publication No. 2007 / 004619 The problem to be solved

[0005] However, there is still room for improvement in photosensitive resin compositions containing DBA to obtain resist patterns of better precision. Additionally, photosensitive resin compositions are typically used in the form of photosensitive elements clamped between polymer films, such as polyethylene; however, according to the inventors' investigation, when a photosensitive resin composition contains DBA, the DBA penetrates the polymer film, which may cause a problem in which a desired pattern shape cannot be formed during resist pattern formation. This problem occurs particularly significantly when the polymer film is a polyethylene film.

[0006] In addition, the photosensitive resin composition containing DBA still has room for improvement in forming a resist pattern with excellent adhesion to a substrate.

[0007] Accordingly, the present disclosure aims to provide a photosensitive resin composition capable of forming a resist pattern having excellent adhesion to a substrate and also having a good pattern shape, a photosensitive element, a method for manufacturing a wiring substrate using the same, and a photosensitive element roll. means of solving the problem

[0008] To achieve the above objective, the present disclosure provides a photosensitive resin composition comprising a binder polymer having a structural unit based on benzyl (meth)acrylate, a photopolymerizable compound, a photopolymerization initiator, and a coumarin-based sensitizer.

[0009] According to the above photosensitive resin composition, by combining a binder polymer having structural units based on benzyl (meth)acrylate with a coumarin-based sensitizer, it is possible to form a resist pattern having excellent adhesion to a substrate and a good pattern shape. This is believed to be because the coumarin-based sensitizer is less likely to penetrate the polymer film compared to DBA, and higher sensitivity can be obtained with a smaller amount of additive, thereby allowing for a good pattern shape of the resist pattern. Furthermore, by using this coumarin-based sensitizer in combination with a binder polymer having structural units based on benzyl (meth)acrylate, the adhesion of the resist pattern to the substrate can be significantly improved. Additionally, since the amount of coumarin-based sensitizer added can be reduced, the amount of solvent required to dissolve the sensitizer can also be reduced. In addition, since coumarin-based sensitizers have lower absorbance compared to DBA, the exposed light can easily reach the depths of the photosensitive resin layer during resist pattern formation, thereby increasing the photocurability of the bottom portion of the photosensitive resin layer. Consequently, adhesion, resolution, and pattern shape can be further improved.

[0010] In the above photosensitive resin composition, the content of the coumarin-based sensitizer may be 0.01 to 0.5 mass parts per 100 mass parts of the total amount of the binder polymer and the photopolymerizable compound. By keeping the content of the coumarin-based sensitizer within the above range, excellent adhesion of the resist pattern and good pattern shape can be achieved at a higher level.

[0011] In the above photosensitive resin composition, the binder polymer may have a content ratio of structural units based on benzyl (meth)acrylate of 10 to 60 mass% based on the total amount of monomers constituting the binder polymer.

[0012] In the above photosensitive resin composition, the binder polymer may have a structural unit based on styrene. By including a structural unit based on styrene in the binder polymer, excellent adhesion of the resist pattern and good pattern shape can be achieved at a higher level. In addition, the content ratio of the structural unit based on styrene in the binder polymer may be 10 to 50 mass% based on the total amount of monomer constituting the binder polymer.

[0013] In the above photosensitive resin composition, the binder polymer may have a structural unit based on an alkyl (meth)acrylate. In addition, the content ratio of the structural unit based on an alkyl (meth)acrylate may be 5 to 40 mass% based on the total amount of monomers constituting the binder polymer.

[0014] In the above photosensitive resin composition, the binder polymer may have a structural unit based on (meth)acrylic acid. In addition, the content ratio of the structural unit based on (meth)acrylic acid may be 10 to 40 mass% based on the total amount of monomer constituting the binder polymer.

[0015] The above photosensitive resin composition may contain a polymerization inhibitor. In addition, the content of the polymerization inhibitor in the above photosensitive resin composition may be 0.003 parts by mass or less with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound. By keeping the content of the polymerization inhibitor within the above range, the pattern shape of the resist pattern can be made better.

[0016] In addition, the content of the polymerization inhibitor in the photosensitive resin composition may be 0.001 parts by mass or more with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound. By keeping the content of the polymerization inhibitor within the above range, excellent adhesion of the resist pattern and good pattern shape can be achieved at a higher level, and at the same time, the occurrence of thickening of the resist pattern lines can be suppressed.

[0017] In addition, the polymerization inhibitor may contain tert-butylcatechol. By including tert-butylcatechol in the polymerization inhibitor, excellent adhesion and good pattern shape of the resist pattern can be achieved at a higher level, and the occurrence of thickening of the resist pattern lines can be suppressed.

[0018] The above photosensitive resin composition may contain 2,6-di-tert-butyl-p-cresol as an antioxidant. In addition, the content of 2,6-di-tert-butyl-p-cresol in the above photosensitive resin composition may exceed 0.002 parts by mass with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound. By keeping the content of 2,6-di-tert-butyl-p-cresol within the above range, the adhesion of the resist pattern can be further improved, and the occurrence of thickening of the resist pattern lines can be suppressed.

[0019] In the above photosensitive resin composition, the photopolymerization initiator may contain a 2,4,5-triarylimidazole dimer.

[0020] In the above photosensitive resin composition, the photopolymerizable compound may contain a bisphenol A type di(meth)acrylate compound. In addition, the bisphenol A type di(meth)acrylate compound may include 2,2-bis(4-((meth)acryloxypentaethoxy)phenyl)propane and / or 2,2-bis(4-((meth)acryloxydiethoxy)phenyl)propane.

[0021] The above photosensitive resin composition may contain leucocrystalline violet.

[0022] The present disclosure further provides a photosensitive element comprising a support and a photosensitive resin layer formed on the support using the photosensitive resin composition of the present disclosure.

[0023] The present disclosure also provides a method for manufacturing a wiring substrate, comprising the steps of: forming a photosensitive resin layer on a substrate using the photosensitive resin composition of the present disclosure or the photosensitive element of the present disclosure; photocuring a portion of the photosensitive resin layer; removing an uncured portion of the photosensitive resin layer to form a resist pattern; and forming a wiring layer on a portion of the substrate where the resist pattern is not formed.

[0024] The present disclosure further provides a photosensitive element roll comprising a winding core and a photosensitive element of the present disclosure wound on said winding core. Effects of the invention

[0025] According to the present disclosure, a photosensitive resin composition capable of forming a resist pattern having excellent adhesion to a substrate and also having a good pattern shape, a photosensitive element, a method for manufacturing a wiring substrate using the same, and a photosensitive element roll can be provided. Brief explanation of the drawing

[0026] FIG. 1 is a schematic cross-sectional view showing a photosensitive element according to one embodiment. FIG. 2 is a schematic diagram showing a method for manufacturing a wiring board according to one embodiment. Specific details for implementing the invention

[0027] Hereinafter, embodiments of the present invention will be described in detail.

[0028] In this specification, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, provided that the desired function of the process is achieved. In this specification, numerical ranges indicated by "~" represent a range that includes the values ​​listed before and after "~" as minimum and maximum values, respectively. "(Meth)acrylic acid" means at least one of "acrylic acid" and the corresponding "methacrylic acid." The same applies to other similar expressions such as (meth)acrylate. In this specification, "EO modification" means a compound having a (poly)oxyethylene group.

[0029] In this specification, the amount of each component in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specifically stated, in cases where multiple substances corresponding to each component exist in the composition. In this specification, "solid content" refers to the non-volatile content in a photosensitive resin composition, excluding volatile substances (water, solvent, etc.). That is, "solid content" refers to the components other than the solvent that remain without volatilizing upon drying of the photosensitive resin composition described below, and includes those that are liquid, syrup-like, or wax-like at room temperature (25°C).

[0030] <Photosensitive resin composition>

[0031] The photosensitive resin composition according to the present embodiment comprises (A) component: a binder polymer, (B) component: a photopolymerizable compound, (C) component: a photopolymerization initiator, and (D) component: a coumarin-based sensitizer. Herein, component (A) has a structural unit based on benzyl (meth)acrylate. In addition, the photosensitive resin composition according to the present embodiment may further comprise (E) component: a polymerization inhibitor. Each component is described below.

[0032] (A) Component: Binder polymer

[0033] The photosensitive resin composition comprises one or more of component (A). As component (A), it contains a binder polymer having a structural unit based on benzyl (meth)acrylate. Additionally, the aromatic ring of the benzyl (meth)acrylate may have a substituent.

[0034] In the binder polymer of component (A), the content ratio of structural units based on benzyl (meth)acrylate is preferably 10 to 60 mass% based on the total amount of monomers constituting component (A), more preferably 15 to 55 mass%, more preferably 15 to 35 mass%, particularly preferably 20 to 30 mass%, and extremely preferably 20 to 23 mass%. By doing so, both the adhesion and resist peeling characteristics of the photosensitive resin composition layer containing the photosensitive resin composition to a circuit-forming substrate can be improved. In addition, the content ratio of structural units based on benzyl (meth)acrylate may be less than 23 mass% based on the total amount of monomers constituting component (A), and may be 22 mass% or less.

[0035] The above binder polymer may have a structural unit based on styrene in order to further improve resolution and adhesion. In addition, the styrene may have a substituent such as vinyltoluene, α-methylstyrene, etc.

[0036] The content ratio of structural units based on styrene may be 10 mass% or more, 20 mass% or more, or 30 mass% or more, based on the total amount of monomer constituting component (A), in terms of improving resolution, and 50 mass% or less, 45 mass% or less, or 40 mass% or less in terms of excellent peeling properties.

[0037] The above binder polymer may have structural units based on (meth)acrylate alkyl esters in order to improve alkali development properties and peeling properties. Among (meth)acrylate alkyl esters, it may have structural units based on methyl (meth)acrylate.

[0038] The content ratio of structural units based on (meth)acrylate alkyl esters may be 5 mass% or more, 10 mass% or more, or 14 mass% or more based on the total amount of monomers constituting component (A), in terms of excellent peelability, and 40 mass% or less, 30 mass% or less, or 20 mass% or less based on the view that resolution and adhesion are further improved.

[0039] The above binder polymer may have structural units based on (meth)acrylic acid. The content ratio of structural units based on (meth)acrylic acid may be 10 to 40 mass% based on the total amount of monomers constituting component (A), 15 to 30 mass%, 20 to 30 mass%, or 20 to 25 mass%. By doing so, both resist peeling characteristics and developability can be improved.

[0040] (A) The acid value of component (A) may be 60 mg KOH / g or more, 65 mg KOH / g or more, 70 mg KOH / g or more, or 75 mg KOH / g or more from the perspective of being able to develop it suitably, and may be 250 mg KOH / g or less, 240 mg KOH / g or less, or 230 mg KOH / g or less from the perspective of improving the adhesion (resistance to developer) of the cured product of the photosensitive resin composition. The acid value of component (A) may be adjusted by the content of structural units constituting component (A) (e.g., structural units derived from (meth)acrylic acid).

[0041] (A) The weight average molecular weight (Mw) of component (A) may be 10,000 or more, 20,000 or more, or 25,000 or more from the viewpoint of excellent adhesion (developer resistance) of the cured product of the photosensitive resin composition, or 80,000 or less, 50,000 or less, or 40,000 or less from the viewpoint of suitably developing. (A) The degree of dispersion (Mw / Mn) of component (A) may be, for example, 1.5 or more or 2.0 or more, or 3.5 or less or 3.3 or less from the viewpoint of further improving adhesion and resolution.

[0042] The weight-average molecular weight and dispersion can be measured, for example, by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene. More specifically, they can be measured under the conditions described in the examples. Furthermore, for compounds with low molecular weight, if it is difficult to measure the weight-average molecular weight using the method described above, the molecular weight may be measured by another method and the average calculated.

[0043] (A) The content of the component may be 20 mass% or more, 30 mass% or more, or 40 mass% or more based on the total amount of solids of the photosensitive resin composition, in terms of excellent moldability of the film, or 90 mass% or less, 80 mass% or less, or 65 mass% or less based on better sensitivity and resolution.

[0044] The content of component (A) may be 30 parts by mass or more, 35 parts by mass or more, or 40 parts by mass or more with respect to 100 parts by mass of the total amount of component (A) and component (B), from the perspective of excellent moldability of the film, and may be 70 parts by mass or less, 65 parts by mass or less, or 60 parts by mass or less with respect to the perspective of further improving sensitivity and resolution.

[0045] The photosensitive resin composition may or may not include a binder polymer other than component (A) (i.e., a binder polymer that does not have a structural unit based on benzyl (meth)acrylate).

[0046] (B) Component: Photopolymerizable compound

[0047] The photosensitive resin composition comprises one or more of component (B). Component (B) may be a compound that polymerizes upon exposure to light, and for example, may be a compound having ethylenically unsaturated bonds.

[0048] (B) The component may include a bisphenol A type di(meth)acrylate compound to further improve alkali development, resolution, and peelability after curing.

[0049] Examples of bisphenol A type di(meth)acrylate compounds include 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane (2,2-bis(4-((meth)acryloxypentaethoxy)phenyl)propane, etc.), 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane, etc.

[0050] (B) The component may include 2,2-bis(4-((meth)acryloxypentaethoxy)phenyl)propane or 2,2-bis(4-((meth)acryloxydiethoxy)phenyl)propane to further improve resolution and peeling properties, and 2,2-bis(4-((meth)acryloxypentaethoxy)phenyl)propane and 2,2-bis(4-((meth)acryloxydiethoxy)phenyl)propane may be used in combination.

[0051] The content of the bisphenol A type di(meth)acrylate compound may be 60 mass% or more or 70 mass% or more based on the total amount of component (B) in order to further improve the resolution of the resist, and may be 99 mass% or less, 95 mass% or less, or 90 mass% or less.

[0052] (B) The component may include trimethylolpropane tri(meth)acrylate or tetramethylolmethane tri(meth)acrylate to further improve peelability, adhesion, and flexibility. Additionally, trimethylolpropane tri(meth)acrylate or tetramethylolmethane tri(meth)acrylate may be EO modified, PO modified, or EO·PO modified.

[0053] The content of trimethylolpropane tri(meth)acrylate or tetramethylolmethane tri(meth)acrylate may be 1 mass% or more or 10 mass% or more based on the total amount of component (B) to further improve developability, adhesion, and pattern shape, and may be 30 mass% or less or 25 mass% or less based on further improving peelability.

[0054] (B) The content of the component may be 3 mass% or more, 10 mass% or more, or 25 mass% or more, based on the total amount of solids in the photosensitive resin composition, in order to further improve sensitivity and resolution, and 70 mass% or less, 60 mass% or less, or 50 mass% or less in order to improve the moldability of the film.

[0055] (C) Component: Photopolymerization initiator

[0056] The photosensitive resin composition comprises one or more of component (C). Examples of component (C) include 2,4,5-triarylimidazole dimer, aromatic ketone compound, benzoin compound, phosphine oxide compound, etc.

[0057] (C) The component may include a 2,4,5-triarylimidazole dimer in order to further inhibit the penetration of the photosensitizer into the polyethylene film. The hydrogen atoms bonded to the phenyl group in the 2,4,5-triarylimidazole dimer may be substituted with halogen atoms (such as chlorine atoms).

[0058] Examples of 2,4,5-triarylimidazole dimers include 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-bis-(m-methoxyphenyl)imidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer. In terms of further inhibiting the penetration of the photosensitizer into the polyethylene film, the 2,4,5-triarylimidazole dimer may be 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer or 2,2-bis(o-chlorophenyl)-4,5,4',5'-tetraphenyl-1,2'-biimidazole.

[0059] The content of 2,4,5-triarylimidazole dimer may be 90 mass% or more, 95 mass% or more, or 99 mass% or more based on the total amount of component (C), in order to further inhibit the penetration of the photosensitizer into the polyethylene film. Component (C) may consist only of 2,4,5-triarylimidazole dimer.

[0060] (C) The content of the component may be 1 mass% or more, 2 mass% or more, or 3 mass% or more based on the total amount of solids of the photosensitive resin composition, in order to further improve sensitivity and adhesion, and may be 10 mass% or less, 8 mass% or less, or 6 mass% or less.

[0061] (D) Ingredient: Coumarin-based sensitizer

[0062] The photosensitive resin composition contains one or more of the components (D). The component (D) is used as a photosensitizer. Examples of the component (D) include compounds represented by the following general formula (1).

[0063] [Chemical Formula 1]

[0064]

[0065] Food in, Z 1 and Z 2Each represents independently a halogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an amino group, an alkylamino group having 1 to 10 carbon atoms, a dialkylamino group having 2 to 20 carbon atoms, a mercapto group, an alkyl mercapto group having 1 to 10 carbon atoms, an allyl group, a hydroxyalkyl group having 1 to 20 carbon atoms, a carboxyl group, a carboxyalkyl group having 1 to 10 carbon atoms, an acyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 1 to 20 carbon atoms, or a group containing a heterocyclic ring, where n is an integer from 0 to 4 and m is an integer from 0 to 2. Additionally, n Z 1 and m Z 2 At least two of them may form a ring.

[0066] In general formula (1), at least one Z 1 It is preferable that is substituted into the 7th position, and at least one Z 2 It is desirable that the 4th position be substituted. Also, regarding sensitivity, it is desirable that the 3rd position not be substituted.

[0067] Examples of halogen atoms in general formula (1) include fluorine, chlorine, bromine, iodine, and astatine, and examples of alkyl groups having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group and structural isomers thereof. In addition, examples of cycloalkyl groups having 3 to 10 carbon atoms include cyclopropyl groups, cyclobutyl groups, cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclooctyl groups, etc. Examples of aryl groups having 6 to 14 carbon atoms include phenyl groups, tolyl groups, xylyl groups, biphenyl groups, naphthyl groups, anthryl groups, phenanthryl groups, etc., and these may be substituted with halogen atoms, amino groups, nitro groups, cyano groups, mercapto groups, allyl groups, alkyl groups having 1 to 20 carbon atoms, etc. Examples of alkylamino groups having 1 to 10 carbon atoms include methylamino groups, ethylamino groups, propylamino groups, isopropylamino groups, etc. Examples of dialkylamino groups having 2 to 20 carbon atoms include dimethylamino groups, diethylamino groups, dipropylamino groups, diisopropylamino groups, etc. In addition, examples of alkyl mercapto groups having 1 to 10 carbon atoms include methyl mercapto groups, ethyl mercapto groups, propyl mercapto groups, etc. Also, examples of hydroxyalkyl groups having 1 to 20 carbon atoms include hydroxymethyl groups, hydroxyethyl groups, hydroxypropyl groups, hydroxyisopropyl groups, hydroxybutyl groups, etc., and examples of carboxyalkyl groups having 1 to 10 carbon atoms include carboxymethyl groups, carboxyethyl groups, carboxypropyl groups, carboxybutyl groups, etc.In addition, examples of acyl groups having 1 to 10 carbon atoms of the alkyl group include a formyl group, acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group, isovaleryl group, pivaloyl group, etc., and examples of alkoxy groups having 1 to 20 carbon atoms include a methoxy group, ethoxy group, propoxy group, butoxy group, etc., and examples of alkoxycarbonyl groups having 1 to 20 carbon atoms include a methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, butoxycarbonyl group, etc., and examples of groups containing a heterocyclic group include a furyl group, thieneyl group, pyrroleyl group, thiazoleyl group, indoleyl group, quinolyl group, etc.

[0068] In general formula (1), Z 1 and Z 2 Preferably, each is independently an alkyl group having 1 to 20 carbon atoms, an amino group, an alkylamino group having 1 to 10 carbon atoms, or a dialkylamino group having 2 to 20 carbon atoms. Even in this case, n Z 1 and m Z 2 At least two of them may form a ring.

[0069] In terms of resolution and light sensitivity, the coumarin compound represented by general formula (1) is more preferably a compound represented by the following general formula (2). Also, among general formula (2), Z 1 , Z 2 and m is the above Z 1 , Z 2 and has the same meaning as m, and Z 11 and Z 12 , each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and r is an integer from 0 to 3. In addition, r Z 1 , m Z 2 , Z 11 and Z 12 At least two of them may form a ring. And, in the compound represented by the following general formula (2), Z 11 and Z 12It is preferable that each is independently an alkyl group having 1 to 10 carbon atoms, and more preferable that it is an alkyl group having 1 to 6 carbon atoms. In addition, suitable Z 1 and Z 2 It is the same as above.

[0070] [Chemical Formula 2]

[0071]

[0072] It is a compound represented by the general formula (2), with m Z 2 , Z 11 and Z 12 Examples of forms in which at least two of them form a ring include compounds represented by the following general formula (3) and compounds represented by the following general formula (4).

[0073] [Chemical Formula 3]

[0074]

[0075] Food in, Z 1 , Z 11 , Z 12 and r is the above Z 1 , Z 11 , Z 12 and has the same meaning as r, and Z 21 Silver, the above Z 1 Represents an atom or group identical to . Also, s represents an integer from 0 to 8. Also, suitable Z 1 , Z 11 and Z 12 It is the same as above.

[0076] [Chemical Formula 4]

[0077]

[0078] Food in, Z 1 , Z 2 and m is the above Z 1 , Z 2 and has the same meaning as m, and Z 31 and Z 32 Each independently of the above Z 1Represents an atom or group identical to . Also, t represents an integer from 0 to 1, u represents an integer from 0 to 6, and v represents an integer from 0 to 6, respectively. Also, suitable Z 1 and Z 2 It is the same as above.

[0079] As compounds represented by general formula (2) (including compounds represented by general formulas (3) and (4)), 7-amino-4-methylcoumarin, 7-dimethylamino-4-methylcoumarin, 7-diethylamino-4-methylcoumarin (compound represented by formula (5) below), 7-methylamino-4-methylcoumarin, 7-ethylamino-4-methylcoumarin, 4,6-dimethyl-7-ethylaminocoumarin (compound represented by formula (6) below), 4,6-diethyl-7-ethylaminocoumarin, 4,6-dimethyl-7-diethylaminocoumarin, 4,6-dimethyl-7-dimethylaminocoumarin, 4,6-diethyl-7-diethylaminocoumarin, 4,6-dimethyl-7-dimethylaminocoumarin, 4,6-dimethyl-7-ethylaminocoumarin, Examples include 7-dimethylaminocyclopenta[c]coumarin (compound represented by formula (7) below), 7-aminocyclopenta[c]coumarin, 7-diethylaminocyclopenta[c]coumarin, 2,3,6,7,10,11-hexaanhydro-1H,5H-cyclopenta[3,4][1]benzopyrano[6,7,8-ij]quinolizine 12(9H)-one, 7-diethylamino-5',7'-dimethoxy-3,3'-carbonylbiscoumarin, 3,3'-carbonylbis[7-(diethylamino)coumarin], 7-(diethylamino)-3-(2-thienyl)coumarin, and compounds represented by formula (8) below.

[0080] [Chemical Formula 5]

[0081]

[0082] A particularly preferred coumarin compound represented by general formula (1) is a compound represented by general formula (4). By combining a compound represented by general formula (4) as component (D) and a binder polymer having a structural unit based on benzyl (meth)acrylate as component (A), sensitivity, adhesion, and resolution can be greatly improved, and these effects can be sufficiently obtained by adding only a small amount of component (D).

[0083] The content of component (D) is, for example, 0.01 parts by mass or more, preferably 0.02 parts by mass or more, more preferably 0.03 parts by mass or more, and even more preferably 0.04 parts by mass or more, with respect to 100 parts by mass of the total amount of components (A) and (B), in order to further improve sensitivity, adhesion and resolution, and for example, 0.5 parts by mass or less, preferably 0.4 parts by mass or less, more preferably 0.3 parts by mass or less, even more preferably 0.2 parts by mass or less, particularly preferably 0.15 parts by mass or less, and extremely preferably 0.1 parts by mass or less, in order to further improve the resist pattern shape.

[0084] The photosensitive resin composition may further contain a known photosensitive agent as an additional photosensitive agent in addition to component (D). The content of the additional photosensitive agent may be, for example, 0.01 to 0.50 parts by mass or 0.05 to 0.20 parts by mass with respect to 100 parts by mass of the total amount of components (A) and (B).

[0085] (E) Ingredient: Polymerization inhibitor

[0086] The photosensitive resin composition may further contain (E) component: a polymerization inhibitor, in order to suppress polymerization in unexposed areas during resist pattern formation and further improve resolution. The polymerization inhibitor may be, for example, tert-butylcatechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, etc.

[0087] As polymerization inhibitors, for example, alkylcatechols such as catechol, resorcinol (resosin), 1,4-hydroquinone, 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethylcatechol, 2-propylcatechol, 3-propylcatechol, 4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol, 4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol, 4-tert-butylcatechol, 3,5-di-tert-butylcatechol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol (orsin), 2-ethylresorcinol, 4-ethylresorcinol, Examples include alkylesosinols such as 2-propylesosinol, 4-propylesosinol, 2-n-butylesosinol, 4-n-butylesosinol, 2-tert-butylesosinol, and 4-tert-butylesosinol; alkylhydroquinones such as methylhydroquinone, ethylhydroquinone, propylhydroquinone, tert-butylhydroquinone, and 2,5-di-tert-butylhydroquinone; pyrogallol; phloroglucin, and 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl. These may be used individually or in combination of two or more.

[0088] By containing component (D), the photosensitive resin composition can suppress polymerization in the unexposed area during resist pattern formation, even without containing a polymerization inhibitor, compared to the case where a conventional photosensitizer (e.g., DBA) is contained, thereby enabling the formation of a resist pattern with better precision. Accordingly, the content of component (E) may be 0.01 parts by mass or less, 0.005 parts by mass or less, 0.003 parts by mass or less, 0.0025 parts by mass or less, or 0.002 parts by mass or less, relative to 100 parts by mass of the total amount of components (A) and (B), and the photosensitive resin composition may not contain component (E). Meanwhile, by containing component (E), the photosensitive resin composition can further improve adhesion and the shape of the resist pattern, and can also suppress the occurrence of thickening of the resist pattern lines. For this reason, the content of component (E) may be 0.001 parts by mass or more, 0.0015 parts by mass or more, or 0.002 parts by mass or more, with respect to 100 parts by mass of the total amount of components (A) and (B).

[0089] The photosensitive resin composition may further contain one or more other components in addition to the components described above. Examples of other components include hydrogen donors (bis[4-(dimethylamino)phenyl]methane, bis[4-(diethylamino)phenyl]methane, leucocrystalline violet, N-phenylglycine, etc.), dyes (malachite green, etc.), tribromophenylsulfone, photochromic agents, heat-inhibiting agents, plasticizers (p-toluenesulfonamide, etc.), pigments, fillers, defoaming agents, flame retardants, stabilizers, adhesion promoters, leveling agents, peeling accelerators, antioxidants, fragrances, imaging agents, thermal crosslinking agents, etc. The content of other components may be 0.005 parts by mass or more or 0.01 parts by mass or more, and 20 parts by mass or less, with respect to 100 parts by mass of the total amount of components (A) and (B).

[0090] Examples of antioxidants include alkylated phenols such as 2,6-di-tert-butyl-4-methylphenol, alkylated bisphenols such as 2,2-methylenebis(4-methyl-6-tert-butylphenol), 1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 2-4-hydroxy-3,5-di-tert-butylanilino-4,6-bis(n-octylthio)-1,3,5-triazine, dilaurylthiodipropionate benzotriazole, benzotriazole hydrochloride, benzotriazole organic acid salt, aminobenzothiazole, etc. In addition, as antioxidants, phenols such as 4,4'-butylidene-bis(6-tert-butyl-m-cresol), 2,2'-methylene-bis(4-ethyl-6-tert-butylphenol), 4,4'-thio-bis(6-tert-butyl-m-cresol), 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-amylhydroquinone, 2,5-di-tert-butylhydroquinone, 2-methyl-4,6-bis[(octylthio)methyl]phenol, and 2,4-bis(dodecylthiomethyl)-6-methylphenol may be used. These may be used individually or in combination of two or more.

[0091] It is preferable that the antioxidant include 2,6-di-tert-butyl-p-cresol (alias: dibutylhydroxytoluene, abbreviation: BHT). By including BHT in the photosensitive resin composition, adhesion and resist pattern shape can be further improved, and the occurrence of thickening of the resist pattern lines can be suppressed.

[0092] The content of the antioxidant in the photosensitive resin composition may be 0.001 parts by mass or more, 0.002 parts by mass or more, more than 0.002 parts by mass, 0.003 parts by mass or more, or 0.005 parts by mass or more, or 0.5 parts by mass or less, 0.3 parts by mass or less, or 0.1 parts by mass or less, based on 100 parts by mass of the total amount of component (A) and component (B). By ensuring that the content of the antioxidant is at least the lower limit value, the adhesion and the shape of the resist pattern can be further improved, and the occurrence of thickening of the resist pattern lines can be suppressed. Additionally, by ensuring that the content of the antioxidant is at least the upper limit value, a significant decrease in sensitivity can be suppressed.

[0093] The photosensitive resin composition may further contain one or more types of organic solvents for the purpose of adjusting viscosity. Examples of organic solvents include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, etc. The content of the organic solvent may be 40 mass% or more and 70 mass% or less based on the total amount of the photosensitive resin composition. As for the organic solvent, a mixed solvent of toluene and other solvents (methanol, ethanol, methyl cellosolve, ethyl cellosolve, etc.) may be used. When the photosensitive resin composition contains a coumarin-based sensitizer, good solubility is easily obtained even when the proportion of toluene in the mixed solvent is reduced, so the amount of toluene used can be reduced.

[0094] The photosensitive resin composition can be suitably used for forming a resist pattern and can be particularly suitable for the method of manufacturing a wiring substrate described below.

[0095] Photosensitive element

[0096] FIG. 1 is a schematic cross-sectional view of a photosensitive element according to one embodiment. As shown in FIG. 1, the photosensitive element (1) comprises a support (2), a photosensitive resin layer (3) provided on the support (2), and a protective layer (4) provided on the side opposite to the support (2) of the photosensitive resin layer (3).

[0097] The support (2) and the protective layer (4) may each be a polymer film having heat resistance and solvent resistance, and may be, for example, a polyolefin film such as a polyester film such as a polyethylene terephthalate film, a polyethylene film, or a polypropylene film. The support (2) and the protective layer (4) may each be a film of a hydrocarbon polymer other than a polyolefin. A film of a hydrocarbon polymer containing a polyolefin may have a low density, for example, a density of 1.014 g / cm³ or less. The support (2) and the protective layer (4) may each be a stretched film formed by stretching the said low-density hydrocarbon polymer film. The type of polymer film constituting the protective layer (4) may be the same as or different from the type of polymer film constituting the support (2).

[0098] These polymer films can be purchased as polyethylene terephthalate films such as the PS series (e.g., PS-25) manufactured by Teijin Corporation, polyethylene films such as NF-15 manufactured by Tamapoly Corporation, or polypropylene films such as those manufactured by Oji Seishi Corporation (e.g., Arpan MA-410, E-200C) and Shin-Etsu Film Corporation.

[0099] The thickness of the support (2) may be 1 μm or more or 5 μm or more in order to suppress damage to the support (2) when peeling the support (2) from the photosensitive resin layer (3), and may be 100 μm or less, 50 μm or less, or 30 μm or less in order to suitably expose light when exposing through the support (2).

[0100] The thickness of the protective layer (4) may be 1 μm or more, 5 μm or more, or 15 μm or more from the perspective of suppressing damage to the protective layer (4) when the photosensitive resin layer (3) and the support (2) are laminated on the substrate while peeling off the protective layer (4), and may be 100 μm or less, 50 μm or less, or 30 μm or less from the perspective of improving productivity.

[0101] The photosensitive resin layer (3) is composed of the photosensitive resin composition described above. The thickness of the photosensitive resin layer (3) after drying (or after volatilizing the organic solvent in cases where the photosensitive resin composition contains an organic solvent) may be 1 μm or more or 5 μm or more from the perspective of facilitating coating and improving productivity, or 100 μm or less, 50 μm or less, or 40 μm or less from the perspective of further improving adhesion and resolution.

[0102] A photosensitive element (1) can be obtained, for example, as follows. First, a photosensitive resin layer (3) is formed on a support (2). The photosensitive resin layer (3) can be formed, for example, by applying a photosensitive resin composition containing an organic solvent to form a coating layer and drying the coating layer. Next, a protective layer (4) is formed on the surface of the photosensitive resin layer (3) opposite to the support (2).

[0103] The coating layer is formed by known methods such as, for example, roll coating, comma coating, gravure coating, air knife coating, die coating, bar coating, etc. The drying of the coating layer is performed so that the amount of organic solvent remaining in the photosensitive resin layer (3) is, for example, 2 mass% or less, and specifically, is performed for about 5 to 30 minutes at, for example, 70 to 150°C.

[0104] In another embodiment, the photosensitive element may not have a protective layer and may further have other layers such as a cushion layer, an adhesive layer, a light-absorbing layer, or a gas barrier layer.

[0105] The photosensitive element (1) may, for example, be in the form of a sheet or in the form of a photosensitive element roll wound on a winding core. In the photosensitive element roll, the photosensitive element (1) is preferably wound so that the support (2) is on the outside. The winding core is formed of, for example, polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, etc. On the edge surface of the photosensitive element roll, an edge surface separator may be provided for edge surface protection, or a moisture-proof edge surface separator may be provided for edge fusion. The photosensitive element (1) may, for example, be wrapped in a black sheet with low moisture permeability.

[0106] The photosensitive element (1) can be suitably used for forming a resist pattern and can be particularly suitable for the method of manufacturing a wiring board described below. Since the photosensitive element (1) can suppress the penetration of a photosensitive agent into a polyethylene film compared to a conventional photosensitive element, at least one of the support (2) and the protective layer (4) may be a polyethylene film, or may be the low-density hydrocarbon-based polymer film or a stretched film thereof described above.

[0107] Method for manufacturing a wiring board

[0108] FIG. 2 is a schematic diagram illustrating a method for manufacturing a wiring board (also called a printed circuit board) according to one embodiment. In this manufacturing method, first, as shown in FIG. 2 (a), a substrate (e.g., a circuit forming substrate) is prepared having an insulating layer (11) and a conductive layer (12) formed on the insulating layer (11). The conductive layer (12) may be, for example, a metal copper layer.

[0109] Next, as shown in FIG. 2(b), a photosensitive resin layer (13) is provided on a substrate (conductor layer (12)). In this process, a photosensitive resin layer (13) made of the photosensitive resin composition described above is formed on the substrate (conductor layer (12)) using the photosensitive resin composition or photosensitive element (1) described above. For example, the photosensitive resin layer (13) is formed by applying and drying the photosensitive resin composition on the substrate. Alternatively, the photosensitive resin layer (13) is formed by removing the protective layer (4) from the photosensitive element (1) and then pressing the photosensitive resin layer (3) of the photosensitive element (1) against the substrate while heating. When pressing, at least one of the photosensitive resin layer (3) and the substrate may be heated, for example, at 70 to 130°C. The pressure during pressing may be, for example, 0.1 to 1.0 MPa.

[0110] Next, as shown in FIG. 2(c), a mask (14) is placed on the photosensitive resin layer (13), an active light (15) is irradiated, and the photosensitive resin layer (13) is photocured by exposing the area other than the area where the mask (14) is placed. The light source of the active light (15) may be, for example, an ultraviolet light source or a visible light source such as a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, a gas laser (argon laser, etc.), a solid-state laser (YAG laser, etc.), or a semiconductor laser.

[0111] In another embodiment, without using a mask (14), a portion of the photosensitive resin layer (13) may be exposed by irradiating an active light (15) in a desired pattern using a direct lithography exposure method such as LDI exposure or DLP exposure.

[0112] Next, as shown in (d) of FIG. 2, the area other than the photocured portion formed by exposure (uncured portion) is removed from the substrate by developing, thereby forming a resist pattern (16) consisting of the photocured portion (cured product of the photosensitive resin layer). The developing method may be, for example, wet development or dry development, and preferably wet development.

[0113] Wet development is performed using a developer corresponding to the photosensitive resin composition, for example by a dip method, paddle method, spray method, brushing, slapping, scrubbing, or shaking immersion method. The developer is appropriately selected according to the composition of the photosensitive resin composition and may be an alkaline developer or an organic solvent developer.

[0114] The alkaline developer may be an aqueous solution containing a base such as an alkali hydroxide, such as a hydroxide of lithium, sodium, or potassium; an alkali carbonate, such as a carbonate or bicarbonate of lithium, sodium, potassium, or ammonium; an alkali metal phosphate, such as potassium phosphate or sodium phosphate; an alkali metal pyrophosphate, such as sodium pyrophosphate or potassium pyrophosphate; borax; sodium metasilicate; tetramethylammonium hydroxide; ethanolamine; ethylenediamine; diethylenetriamine; 2-amino-2-hydroxymethyl-1,3-propanediol; 1,3-diamino-2-propanol; or morpholin.

[0115] The alkaline developer may be, for example, a 0.1 to 5 mass% aqueous sodium carbonate solution, a 0.1 to 5 mass% aqueous potassium carbonate solution, a 0.1 to 5 mass% aqueous sodium hydroxide solution, a 0.1 to 5 mass% aqueous sodium tetraborate solution, etc. The pH of the alkaline developer may be, for example, 9 to 11.

[0116] The alkaline developer may further contain a surfactant, an antifoaming agent, an organic solvent, etc. Examples of organic solvents include acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, etc. The content of the organic solvent may be 2 to 90 mass% based on the total amount of the alkaline developer.

[0117] The organic solvent developer may contain organic solvents such as 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methylisobutylketone, and γ-butyrolactone. The organic solvent developer may further contain 1 to 20 mass% of water.

[0118] In this process, after removing the unexposed portion, heating at 60–250°C or 0.2–10 J / cm² is applied as needed. 2 By performing further exposure in the, the resist pattern (16) may be further cured.

[0119] Next, as shown in FIG. 2(e), a wiring layer (17) is formed by performing, for example, a plating treatment on a portion of the conductor layer (12) where the resist pattern (16) is not formed. The wiring layer (17) may be formed of a material of the same type as the conductor layer (12) or of a different type. The wiring layer (17) may be, for example, a metallic copper layer. The plating treatment may be either or both of electrolytic plating and electroless plating.

[0120] Next, as shown in (f) of FIG. 2, the resist pattern (16) is removed, and the conductor layer (12) provided at a position corresponding to the resist pattern (16) is removed. Thus, a wiring substrate (18) having a wiring layer (17) formed on the substrate is obtained.

[0121] The resist pattern (16) can be removed by, for example, by using a strong alkaline aqueous solution and performing a development method such as immersion or spraying. The strong alkaline aqueous solution may be, for example, a 1-10 mass% sodium hydroxide aqueous solution, a 1-10 mass% potassium hydroxide aqueous solution, etc.

[0122] The conductor layer (12) can be removed by etching treatment. The etching solution is appropriately selected according to the type of conductor layer (12), and may be, for example, a copper(II) chloride solution, a ferric chloride solution, an alkaline etching solution, a hydrogen peroxide etching solution, etc.

[0123] Examples

[0124] The present disclosure will be explained more specifically below by way of examples, but the present disclosure is not limited to these examples.

[0125] Synthesis of (A) Component

[0126] Solution (a) was prepared by mixing the monomer shown in Table 1 with 0.9 parts by mass of azobis-isobutyronitrile in the mixing amount (unit: parts by mass) shown in the same table. Solution (b) was prepared by dissolving 0.6 parts by mass of azobis-isobutyronitrile in 50 parts by mass of a mixture (x) of 30 parts by mass of methylcellosolve and 20 parts by mass of toluene. 500 g of the mixture (x) was added to a flask equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel, and a nitrogen gas inlet tube, and the mixture was stirred while injecting nitrogen gas into the flask to raise the temperature to 80°C. Solution (a) was added dropwise to the mixture in the flask at a constant dropping rate over a period of 4 hours, and then stirred at 80°C for 2 hours. Next, the solution (b) was added dropwise to the solution in the flask at a constant rate over a period of 10 minutes, and then the solution in the flask was stirred at 80°C for 3 hours. Additionally, the solution in the flask was heated to 95°C over a period of 30 minutes, held at 95°C for 2 hours, then the stirring was stopped and cooled to room temperature (25°C) to obtain solutions of binder polymers A-1 to A-3. The non-volatile content (solid content) of the solutions of binder polymers A-1 to A-3 was 49.0 mass%. The weight average molecular weight (Mw), glass transition temperature (Tg), and acid value of binder polymers A-1 to A-3 are shown in Table 1.

[0127] In addition, the weight-average molecular weight was determined by measuring it according to gel permeation chromatography (GPC) and converting it using the calibration curve of standard polystyrene. The conditions for the GPC are as follows.

[0128] (GPC conditions)

[0129] Pump: Hitachi L-6000 model (Manufactured by Hitachi Seisakusho Co., Ltd., product name)

[0130] Column: Total of 3 items below

[0131] Gelpack GL-R420

[0132] Gelpack GL-R430

[0133] Gelpack GL-R440 (Manufactured by Hitachi Kasei Co., Ltd., Product Name)

[0134] Eluent: Tetrahydrofuran

[0135] Measured temperature: 40℃

[0136] Flow rate: 2.05 mL / min

[0137] Detector: Hitachi L-3300 type RI (Manufactured by Hitachi Seisakusho Co., Ltd., product name)

[0138] The glass transition temperature was measured using a DSC (PerkinElmer, DSC-7 type) under conditions of a sample volume of 10 mg, a heating rate of 10℃ / min, and an atmosphere of air.

[0139] The acid value was measured by the neutralization titration method based on JIS K0070. First, a solution of binder polymer was heated at 130°C for 1 hour to remove volatile matter and obtain a solid component. Then, 1 g of the binder polymer in the solid component was accurately weighed, 30 g of acetone was added to the binder polymer, and the mixture was uniformly dissolved to obtain a resin solution. Subsequently, an appropriate amount of phenolphthalein, an indicator, was added to the resin solution, and a neutralization titration was performed using a 0.1 mol / L aqueous potassium hydroxide solution. The acid value was then calculated using the following formula.

[0140] Acid value = 0.1 × V × f1 × 56.1 / (Wp × I / 100)

[0141] In the formula, V represents the titration volume (mL) of the 0.1 mol / L potassium hydroxide aqueous solution used for titration, f1 is the factor (concentration conversion factor) of the 0.1 mol / L potassium hydroxide aqueous solution, Wp is the mass (g) of the measured resin solution, and I is the ratio (mass%) of the non-volatile content in the measured resin solution.

[0142] [Table 1]

[0143]

[0144] (Examples 1–9 and Comparative Examples 1–3)

[0145] <Preparation of Photosensitive Resin Composition>

[0146] Each photosensitive resin composition was prepared by mixing each component shown in Table 2 in the mixing amount (parts by mass) shown in the same table. In addition, the mixing amount (parts by mass) of component (A) shown in Table 2 is the mass of the non-volatile content (solid content). The details of each component shown in Table 2 are as follows.

[0147] (B) Component

[0148] FA-321M(70): 70% solution of propylene glycol monomethyl ether of 2,2-bis(4-(methacryloxyethoxy)phenyl)propane (average 10 mol adduct of ethylene oxide) (manufactured by Hitachi Kasei Corporation)

[0149] FA-137M: EO-modified trimethylolpropane trimethacrylate (manufactured by Hitachi Kasei Corporation)

[0150] (C) Component

[0151] BCIM: 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole (Hampford)

[0152] (D) Component

[0153] Coumarin 102: 2,3,6,7-tetrahydro-9-methyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizine-11-one(Tokyo Kasei High School Teacher)

[0154] (D)' component

[0155] DBA: 9,10-Dibutoxycyanthracene (manufactured by Kawasaki Kasei High School Co., Ltd.)

[0156] (E) Component

[0157] DIC-TBC-20: 4-tert-butylcatechol (manufactured by DIC Corporation)

[0158] (Other ingredients)

[0159] BHT: 2,6-di-tert-butyl-p-cresol (antioxidant, manufactured by Fujifilm Wako Junyaku Co., Ltd.)

[0160] LCV: Ryuko Crystal Violet (Yamada Gagaku High School Co., Ltd.)

[0161] SF-808H: Mixture of carboxybenzotriazole, 5-amino-1H-tetrazole, and methoxypropanol (manufactured by Sanwa Kasei Corporation)

[0162] LA-7RD: 4-TEMPO (Asahi Denka High School Co., Ltd.)

[0163] MKG: Malachite Green (Osaka Yuki Gagaku High School Co., Ltd.)

[0164] (solvent)

[0165] TLS: Toluene

[0166] MAL: Methanol

[0167] ACS: Acetone

[0168] Production of photosensitive elements

[0169] A polyethylene terephthalate film (manufactured by Teijin Corporation, product name "HTF-01") with a thickness of 16 μm was prepared as a support, and a photosensitive resin composition was applied onto the support to ensure a uniform thickness. The film was then sequentially dried using a hot air convection dryer at 70°C and 110°C to form a photosensitive resin layer with a thickness of 25 μm after drying. A polyethylene film (manufactured by Tamapoly Co., Ltd., product name "NF-15") was laminated onto this photosensitive resin layer as a protective layer, thereby obtaining a photosensitive element in which the support, the photosensitive resin layer, and the protective layer were laminated in sequence.

[0170] Fabrication of Laminated Structures

[0171] A copper-clad laminate (substrate, manufactured by Hitachi Kasei Co., Ltd., trade name "MCL-E-679"), which is a glass epoxy material with copper foil (thickness: 35 μm) laminated on both sides, was surface-treated using a surface roughening treatment solution "MAC Etch Bond CZ-8100" (manufactured by MAC Co., Ltd., trade name). Subsequently, after washing with water, pickling, and washing with water, it was dried with an air stream. The surface-treated copper-clad laminate was heated to 80°C, and while peeling off the protective layer, the photosensitive elements were each laminated so that the photosensitive resin layer came into contact with the copper surface. In this way, a laminate was obtained in which the copper-clad laminate, the photosensitive resin layer, and the support were laminated in that order. The obtained laminate was used as a test specimen in the test described below. In addition, lamination was performed using a heat roll at 110°C, with a compression pressure of 0.4 MPa and a roll speed of 1.5 m / min.

[0172] <Evaluation>

[0173] (Measurement of absorbance)

[0174] The absorbance of the photosensitive resin layer was measured using a UV spectrophotometer (Spectrophotometer U-3310 manufactured by Hitachi High Technologies Co., Ltd.). The measurement was performed by placing a photosensitive element with the protective layer peeled off on the measurement side and a support film on the reference side, continuously measuring from 300 to 700 nm in absorbance mode, and reading the values ​​at wavelengths 375 nm and 405 nm. The results are shown in Table 2.

[0175] (Measurement of minimum phenomenon time)

[0176] The above laminate was cut into a square with sides of 5 cm to obtain a test specimen for measuring the minimum development time. After peeling the support from the test specimen, an unexposed photosensitive resin layer was spray-developed using a 1 mass% sodium carbonate aqueous solution at 30°C at a pressure of 0.15 MPa, and the shortest time at which the removal of an unexposed area of ​​1 mm or more could be visually confirmed was defined as the minimum development time. A full cone type nozzle was used. The distance between the test specimen and the tip of the nozzle was 6 cm, and the specimen was positioned so that the center of the specimen and the center of the nozzle coincided. A shorter minimum development time (unit: seconds) indicates better developability. The results are shown in Table 2.

[0177] (Evaluation of closeness)

[0178] Using a drawing pattern in which the line width (L) / space width (S) (hereinafter referred to as "L / S") is 3 / 400 to 30 / 400 (unit: μm), exposure (drawing) was performed on the photosensitive resin layer of the laminate with an energy amount such that the number of remaining steps of the 41-step tablet becomes 14 steps.

[0179] After exposure, the support was peeled off from the laminate to expose the photosensitive resin layer, and the unexposed portion was removed by spraying a 1 mass% aqueous sodium carbonate solution at 30°C for 60 seconds. After development, the adhesion was evaluated based on the minimum value between the line width and space width in the resist pattern formed, in which the space portion (unexposed portion) was removed without residue and the line portion (exposed portion) did not meander or cause damage. A smaller value indicates better adhesion. The results are shown in Table 2.

[0180] (Evaluation of resist pattern formation)

[0181] The resist pattern with a line width of 10 μm, prepared through the above adhesion evaluation, was observed using a scanning electron microscope to evaluate the shape of the resist pattern and the presence or absence of line thickening. The shape of the resist pattern was evaluated according to the following evaluation criteria based on the ratio of the width of the top part to the width of the bottom part of the resist pattern (bottom width / top width). The results are shown in Table 2.

[0182] A: Rectangular cross-section (bottom width / top width is 0.9 or greater)

[0183] B: Small tapered cross-sectional shape (bottom width / top width is 0.8 or more and less than 0.9)

[0184] C: Cross-sectional shape is tapered (bottom width / top width is less than 0.8)

[0185] In addition, line thickening was evaluated by measuring the difference between the design dimension of the line width in the drawing pattern and the line width (normal width) of the formed resist pattern, according to the following evaluation criteria. The results are shown in Table 2.

[0186] A: Difference of 0.5μm or less

[0187] B: Difference greater than 0.5μm and less than or equal to 1.0μm

[0188] C: Difference greater than 1.0μm and less than or equal to 2.0μm

[0189] D: Difference exceeds 2.0μm

[0190] [Table 2]

[0191] Explanation of the symbols

[0192] 1… Photosensitive element 2… support body 3, 13… photosensitive resin layer 4… protection layer 11… insulation layer 12… conductor layer 14… mask 15… active light 16… Resist pattern 17… Wiring layer 18… wiring board

Claims

Claim 1 A photosensitive element comprising a support and a photosensitive resin layer formed on the support using a photosensitive resin composition, wherein the photosensitive resin composition comprises a binder polymer having a structural unit based on benzyl (meth)acrylate, a photopolymerizable compound, a photopolymerization initiator, and a coumarin-based sensitizer, wherein the content ratio of the structural unit based on benzyl (meth)acrylate in the binder polymer is 10 to 60 mass% based on the total amount of monomers constituting the binder polymer, and the content of the coumarin-based sensitizer is 0.01 to 0.15 mass parts per 100 mass parts of the total amount of the binder polymer and the photopolymerizable compound, and the coumarin-based sensitizer is a compound represented by the following general formula (4): (in food, Z 1 , Z 2 , Z 31 and Z 32 Each represents independently a halogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an amino group, an alkylamino group having 1 to 10 carbon atoms, a dialkylamino group having 2 to 20 carbon atoms, a mercapto group, an alkyl mercapto group having 1 to 10 carbon atoms, an allyl group, a hydroxyalkyl group having 1 to 20 carbon atoms, a carboxyl group, a carboxyalkyl group having 1 to 10 carbon atoms, an acyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 1 to 20 carbon atoms, or a group containing a heterocyclic ring, and m represents an integer from 0 to 2, t represents an integer from 0 to 1, u represents an integer from 0 to 6, and v represents an integer from 0 to 6. Also, m Z 2 (Two of them may form a ring.) The photopolymerization initiator comprises a 2,4,5-triarylimidazole dimer, wherein the 2,4,5-triarylimidazole dimer is 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, the photopolymerizable compound comprises a bisphenol A type di(meth)acrylate compound, wherein the bisphenol A type di(meth)acrylate compound comprises 2,2-bis(4-((meth)acryloxypentaethoxy)phenyl)propane and / or 2,2-bis(4-((meth)acryloxydiethoxy)phenyl)propane, and further comprises a leucocrystalline violet and 2,6-di-tert-butyl-p-cresol as an antioxidant, a photosensitive element. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 A photosensitive element according to claim 1, wherein the content ratio of a structural unit based on benzyl (meth)acrylate in the binder polymer is 20 to 30 mass% based on the total amount of monomers constituting the binder polymer. Claim 7 A photosensitive element according to claim 1, wherein the binder polymer has a structural unit based on styrene. Claim 8 A photosensitive element according to claim 7, wherein the content ratio of a styrene-based structural unit in the binder polymer is 10 to 50 mass% based on the total amount of monomers constituting the binder polymer. Claim 9 A photosensitive element according to claim 7, wherein the content ratio of a styrene-based structural unit in the binder polymer is 30 to 50 mass% based on the total amount of monomers constituting the binder polymer. Claim 10 A photosensitive element according to claim 1, wherein the binder polymer has a structural unit based on an alkyl meth)acrylate. Claim 11 A photosensitive element according to claim 10, wherein the content ratio of a structural unit based on an alkyl (meth)acrylate ester in the binder polymer is 5 to 40 mass% based on the total amount of monomers constituting the binder polymer. Claim 12 A photosensitive element according to claim 10, wherein the content ratio of a structural unit based on an alkyl (meth)acrylate ester in the binder polymer is 5 to 20 mass% based on the total amount of monomers constituting the binder polymer. Claim 13 A photosensitive element according to claim 1, wherein the binder polymer has a structural unit based on (meth)acrylic acid. Claim 14 A photosensitive element according to claim 13, wherein the content ratio of a structural unit based on (meth)acrylic acid in the binder polymer is 10 to 40 mass% based on the total amount of monomer constituting the binder polymer. Claim 15 A photosensitive element according to claim 13, wherein the content ratio of a structural unit based on (meth)acrylic acid in the binder polymer is 20 to 30 mass% based on the total amount of monomers constituting the binder polymer. Claim 16 A photosensitive element according to claim 1, wherein the photosensitive resin composition contains a polymerization inhibitor. Claim 17 A photosensitive element according to claim 16, wherein the content of the polymerization inhibitor in the photosensitive resin composition is 0.003 parts by mass or less with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound. Claim 18 delete Claim 19 A photosensitive element according to claim 1, wherein the content of the 2,6-di-tert-butyl-p-cresol in the photosensitive resin composition is greater than 0.002 parts by mass with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound. Claim 20 delete Claim 21 delete Claim 22 delete Claim 23 delete Claim 24 delete Claim 25 A photosensitive element according to claim 1, wherein the content of the leucocrystalline violet in the photosensitive resin composition is 0.01 to 0.6 parts by mass with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound. Claim 26 A photosensitive element according to claim 1, wherein the weight average molecular weight of the binder polymer is 25,000 to 50,000. Claim 27 A photosensitive element according to claim 1, wherein the dispersion degree (Mw / Mn) of the binder polymer is 1.5 to 3.

3. Claim 28 A photosensitive element according to claim 1, wherein the acid value of the binder polymer is 75 to 176.1 mgKOH / g. Claim 29 A photosensitive element according to claim 1, wherein the content of the binder polymer in the photosensitive resin composition is 40 to 65 mass% based on the total amount of solids of the photosensitive resin composition. Claim 30 A photosensitive element according to claim 1, wherein the content of the binder polymer in the photosensitive resin composition is 40 to 60 parts by mass with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound. Claim 31 A photosensitive element according to claim 1, wherein the content of the photopolymerizable compound in the photosensitive resin composition is 25 to 50 mass% based on the total amount of solids of the photosensitive resin composition. Claim 32 A photosensitive element according to claim 1, wherein the content of the photopolymerization initiator in the photosensitive resin composition is 3 to 6 mass% based on the total amount of solids of the photosensitive resin composition. Claim 33 A method for manufacturing a wiring substrate, comprising: a process of providing a photosensitive resin layer on a substrate using a photosensitive element described in claim 1; a process of photocuring a portion of the photosensitive resin layer; a process of removing an uncured portion of the photosensitive resin layer to form a resist pattern; and a process of forming a wiring layer on a portion of the substrate where the resist pattern is not formed. Claim 34 A photosensitive element roll comprising a winding core and a photosensitive element described in claim 1 wound on said winding core.

Images