Photosensitive element, method for forming a resist pattern, and method for manufacturing a photosensitive element

Abstract

To provide:a photosensitive element which is not affected by coating and drying conditions and a storage condition of a photosensitive element, and is excellent in sensitivity and resolution; a method for forming a resist pattern; and a method for manufacturing a photosensitive element.SOLUTION: A photosensitive element includes a support film, a photosensitive resin composition layer which is formed on the support film and contains a photosensitive resin composition, and a protective film, wherein the photosensitive resin composition contains the following components: (A) an alkali-soluble polymer, (B) a compound having an ethylenically unsaturated double bond, (C) a sensitizer, (D) a first phenolic polymerization inhibitor, and a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor as a polymerization inhibitor, and a phenothiazine derivative.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a photosensitive element. [Background technology]

[0002] Printed circuit boards are generally manufactured by photolithography. Photolithography is a method of forming a desired wiring pattern on a substrate through the following steps: First, a layer made of a photosensitive resin composition is formed on the substrate, and a resist pattern is formed by pattern exposure and development of the coating film. Next, a conductor pattern is formed by etching or plating. After that, the desired wiring pattern is formed on the substrate by removing the resist pattern on the substrate.

[0003] Generally, in photolithography, resist patterns are formed by either applying a solution of a photosensitive resin composition to a substrate and drying it, or by laminating a photosensitive resin layer of a dry film resist (a photosensitive resin laminate in which a photosensitive resin layer made of a photosensitive resin composition is laminated on a support film) onto a substrate.

[0004] In the manufacture of printed circuit boards, photosensitive elements (photosensitive resin laminates) are frequently used. In the production and use of photosensitive elements, the sensitivity and resolution, which are determined by the selection and combination of polymerization inhibitors and the setting of their content, are important as they affect productivity.

[0005] Conventional photosensitive elements are known to use phenolic polymerization inhibitors (e.g., Patent Document 1) or phenothiazine polymerization inhibitors (Patent Document 2). Furthermore, examples of using a combination of one phenolic polymerization inhibitor and a phenothiazine polymerization inhibitor as polymerization inhibitors in photosensitive resin compositions are also known (Patent Document 3). Moreover, it is known that using two specific phenolic polymerization inhibitors in combination can produce a synergistic effect on radical scavenging (Non-Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2005-227528 [Patent Document 2] Japanese Patent Publication No. 2019-194025 [Patent Document 3] Japanese Patent Application Publication No. 6-345681 [Non-patent literature]

[0007] [Non-Patent Document 1] Journal of the Japan Petroleum Institute, 54, (1), 22-29 (2011) [Overview of the project] [Problems that the invention aims to solve]

[0008] However, the materials described in the above-mentioned Patent Documents 1-3 and Non-Patent Document 1 all still had room for further improvement in terms of sensitivity stability and resolution.

[0009] For example, photosensitive elements using phenolic polymerization inhibitors alone offer excellent resolution, but their sensitivity stability is poor because the content of the photosensitive resin in the photosensitive resin layer changes due to volatilization during the drying process when the photosensitive resin composition is coated onto the support film, or diffusion into the support film and protective film during storage. Photosensitive elements combining multiple phenolic polymerization inhibitors exhibit a high polymerization inhibition effect due to synergistic effects, resulting in even higher resolution compared to using a single phenolic polymerization inhibitor. However, this does not solve the problem of sensitivity stability. Photosensitive elements using phenothiazine polymerization inhibitors alone exhibit excellent sensitivity stability but poor resolution.

[0010] This invention was proposed in view of the above-mentioned conventional circumstances, and the object of this invention is to provide a photosensitive element, a method for forming a resist pattern, and a method for manufacturing a photosensitive element that are not affected by coating and drying conditions or storage conditions of the photosensitive element and have excellent sensitivity stability and resolution. [Means for solving the problem]

[0011] The inventors have found that the above objective can be achieved by the following technical means, and have completed the present invention. The present invention is as follows. [1] A photosensitive element comprising a support film, a photosensitive resin composition layer containing a photosensitive resin composition formed on the support film, and a protective film, The above photosensitive resin composition comprises the following components: (A) Alkali-soluble polymer, (B) Compounds having an ethylenically unsaturated double bond, (C) Sensitizers, and (D) As a polymerization inhibitor, The first phenolic polymerization inhibitor, A second phenolic polymerization inhibitor, which is different from the first phenolic polymerization inhibitor, Phenothiazine derivatives A photosensitive element characterized by including the following. [2] The content of the polymerization inhibitor (D) is as follows: t 1 / 8 ≤ M p / (M1+M2) ≤ t 1 / 2 (where t represents the film thickness of the photosensitive resin composition, and M p , M1, and M2 are the contents (ppm) of a phenothiazine derivative, a first phenolic polymerization inhibitor, and a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, respectively.) The photosensitive element according to [1], which satisfies the following formula. [3] The photosensitive element according to [1] or [2], wherein the first phenolic polymerization inhibitor and the second phenolic polymerization inhibitor are 2,6-di-tert-butyl-p-cresol and 4-methoxyphenol. [4] The photosensitive element according to any one of [1] to [3], wherein the melting point of at least one of the first phenolic polymerization inhibitor and the second phenolic polymerization inhibitor is 100 °C or lower. [5] The photosensitive element according to any one of [1] to [4], wherein the compound (B) having an ethylenically unsaturated double bond contains a compound having a bisphenol A structure. [6] The photosensitive element according to any one of [1] to [5], wherein the protective film is polypropylene or polyethylene terephthalate. [7] The photosensitive element according to any one of [1] to [6], wherein the sensitizer (C) contains an anthracene derivative. [8] The photosensitive element according to any one of [1] to [7], wherein the sensitizer (C) contains a benzophenone derivative. [9] The following steps: A lamination step of laminating the photosensitive element according to any one of [1] to [8] on a substrate, An exposure step of exposing the photosensitive resin layer of the photosensitive resin laminate, and A development step of developing and removing the unexposed portion of the photosensitive resin layer. A method for forming a resist pattern, which includes these steps.

[10] A method for manufacturing a photosensitive element comprising a support film, a photosensitive resin composition layer, and a protective film, comprising the following steps: A compounding step of preparing a photosensitive resin composition solution comprising (A) an alkali-soluble polymer, (B) a compound having an ethylenically unsaturated double bond, (C) a sensitizer, and (D) a first phenolic polymerization inhibitor, a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, a phenothiazine derivative, and a solvent. A coating step in which the photosensitive resin composition solution is applied to the support film, A heating step of heating the coated support film to 90°C or higher, Lamination process of layering protective films, A method for manufacturing a photosensitive element, including [the specified element].

[11] The above manufacturing method further comprises a step of determining the polymerization inhibitor composition, The polymerization inhibitor composition determination step involves determining the assumed film thickness t' of the photosensitive resin composition layer in the photosensitive element to be manufactured, t' 1 / 8 ≤ M p / (M1+M2) ≤ t' 1 / 2 (In the formula, M p A method for producing a photosensitive element according to

[10] , wherein M1 and M2 are the content (ppm) of a phenothiazine derivative, a first phenolic polymerization inhibitor, and a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, respectively. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a photosensitive element with excellent sensitivity stability and resolution, which is not affected by coating and drying conditions or storage conditions of the photosensitive element, a method for forming a resist pattern, and a method for manufacturing a photosensitive element. [Modes for carrying out the invention]

[0013] The following describes in detail an exemplary embodiment of the present invention (hereinafter abbreviated as "this embodiment"). The present invention is not limited to this embodiment and can be implemented in various modifications within the scope of its gist. In this specification, the upper and lower limits of each numerical range can be arbitrarily combined. In this specification, numerical ranges indicated using "~" include both upper and lower limits.

[0014] The photosensitive element of the present invention comprises a support film and a photosensitive resin composition layer formed on the support film, the layer containing a photosensitive resin composition. Furthermore, the photosensitive element of the present invention is characterized by a photosensitive resin composition, (A) Alkali-soluble polymer, (B) Compounds having an ethylenically unsaturated double bond, (C) Sensitizers, and (D) As a polymerization inhibitor, The first phenolic polymerization inhibitor, A second phenolic polymerization inhibitor, which is different from the first phenolic polymerization inhibitor, Phenothiazine derivatives It is characterized by including the following.

[0015] The inventors have come to the realization that by combining three compounds in (D) polymerization inhibitor—a first phenolic polymerization inhibitor, a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, and a phenothiazine derivative—the sensitivity and resolution can be improved. In other words, according to the present invention, it is possible to provide a photosensitive element with excellent sensitivity and resolution that is not affected by manufacturing conditions or storage conditions determined by the film thickness, and a method for forming a resist pattern.

[0016] <Support film> The support film according to this embodiment is a layer or film for supporting the photosensitive resin composition layer, and is preferably a transparent substrate film that transmits active light.

[0017] Examples of transparent base films include films made from synthetic resins such as polyethylene, polypropylene, polycarbonate, and polyethylene terephthalate. Typically, polyethylene terephthalate (PET), which has appropriate flexibility and strength, is preferred. Among these, it is preferable to use a high-quality film with fewer internal foreign matter. Specifically, it is more preferable to use a PET film synthesized using a Ti-based catalyst, a PET film with small lubricant diameter and low content, a PET film containing lubricant on only one side, a thin-film PET film, a PET film with a smoothing treatment on at least one side, or a PET film with a roughening treatment such as plasma treatment on at least one side. This allows the light to be exposed to the photosensitive resin composition layer without being blocked by internal foreign matter, thereby improving the resolution of the photosensitive element.

[0018] The thickness of the support film is preferably 5 μm to 25 μm, and more preferably 6 μm to 20 μm. A thinner support film reduces the number of internal foreign matter, thus preventing a decrease in resolution. However, if the film thickness is less than 5 μm, it can lead to stretching deformation in the winding direction due to tension during the coating and winding manufacturing process, tearing due to minute scratches, or insufficient film strength resulting in wrinkles during lamination.

[0019] At least one side of the support film may be subjected to a smoothing treatment using a calender or the like. This reduces the surface roughness of one side of the support film, particularly the side that comes into contact with the photosensitive resin composition layer, thereby improving the effects of the present invention.

[0020] The haze of the support film is preferably 0.01% to 1.5%, more preferably 0.01% to 1.2%, and even more preferably 0.01% to 0.95%, from the viewpoint of improving the parallelism of the light rays irradiated onto the photosensitive resin composition layer and obtaining higher resolution after exposure and development of the photosensitive element.

[0021] <Photosensitive resin composition layer> The photosensitive resin composition layer is laminated on a support film. The photosensitive resin composition layer according to this embodiment contains (A) an alkali-soluble polymer, (B) a compound having an ethylenically unsaturated double bond, (C) a sensitizer, and (D) a polymerization inhibitor.

[0022] In particular, in the photosensitive element of the present invention, the photosensitive resin composition layer includes (D) a polymerization inhibitor, a first phenolic polymerization inhibitor, a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, and a phenothiazine derivative.

[0023] (A) Alkali-soluble polymer In this embodiment, (A) the alkali-soluble polymer is preferably obtained by polymerizing at least one of the first monomers described later, and more preferably by copolymerizing at least one of the first monomers with at least one of the second monomers described later.

[0024] The first monomer is a monomer having a carboxyl group in its molecule. Examples of the first monomer include (meth)acrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, 4-vinylbenzoic acid, maleic anhydride, and maleic acid semi-ester. Among these, (meth)acrylic acid is preferred, and methacrylic acid is more preferred, from the viewpoint of excellent adhesion and resolution. In this specification, "(meth)acrylic acid" means acrylic acid or methacrylic acid, "(meth)acryloyl group" means acryloyl group or methacryloyl group, and "(meth)acrylate" means "acrylate" or "methacrylate".

[0025] The copolymerization ratio of the first monomer is preferably 10 to 50% by mass, based on the total mass of all monomer components. A copolymerization ratio of 10% by mass or more is preferred from the viewpoint of excellent adhesion and resolution, more preferably 15% by mass or more, even more preferably 18% by mass or more, even more preferably 21% by mass or more, particularly preferably 23% by mass or more, and particularly preferably 24% by mass or more. A copolymerization ratio of 50% by mass or less is preferred from the viewpoint of excellent adhesion and resolution, more preferably 35% by mass or less, even more preferably 30% by mass or less, even more preferably 29% by mass or less, particularly preferably 27% by mass or less, and most preferably 26% by mass or less. When two or more monomers are polymerized and used as the first monomer, it is preferable that the sum of their copolymerization ratios falls within the above range.

[0026] The second monomer is non-acidic and has at least one polymerizable unsaturated group in its molecule. Examples of second monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, isobornyl (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, pentamethylpiperidyl (meth)acrylate, tetramethylpiperidyl (meth)acrylate, tetrahydrofurfuryl ( Examples include (meth)acrylates such as meth)acrylate, phenoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, methoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, and 2-[3-(2H-benzotriazole-2-yl)-4-hydroxyphenyl]ethyl (meth)acrylate; styrene derivatives such as styrene, methylstyrene, vinyltoluene, tert-butoxystyrene, acetoxystyrene, 4-vinylbenzoic acid, styrene dimers, and styrene trimers; vinyl alcohol esters such as vinyl acetate; and (meth)acrylonitrile.

[0027] (A) The weight-average molecular weight Mw of the alkali-soluble polymer is preferably 10,000 to 60,000. A weight-average molecular weight Mw of 60,000 or less is preferable from the viewpoint of achieving both flexibility and resolution of the resist pattern, more preferably 55,000 or less, and even more preferably 50,000 or less. From a similar viewpoint, it is preferable to have a weight-average molecular weight Mw of 10,000 or more, more preferably 12,000 or more, and even more preferably 14,000 or more.

[0028] (A) The degree of dispersion of the alkali-soluble polymer is preferably 1.0 to 6.0, more preferably 1.0 to 5.0, even more preferably 1.0 to 4.0, and particularly preferably 1.0 to 3.0.

[0029] (A) Alkali-soluble polymers may be used individually or in combination of two or more types.

[0030] (A) The synthesis of alkali-soluble polymers is preferably carried out by adding an appropriate amount of a radical polymerization initiator such as benzoyl peroxide or azoisobutyronitrile to a solution obtained by diluting one or more monomers described above with a solvent such as acetone, methyl ethyl ketone, or isopropanol, and then heating and stirring. In some cases, the synthesis may be carried out by adding a portion of the mixture dropwise to the reaction solution. After the reaction is complete, the solvent may be further added to adjust to the desired concentration. In addition to solution polymerization, living radical polymerization, bulk polymerization, suspension polymerization, or emulsion polymerization may also be used as synthesis methods.

[0031] (A) The ratio of alkali-soluble polymer to the total solid content mass of the photosensitive resin composition may be 10% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, 45% by mass or more, 50% by mass or more, 55% by mass or more, or 60% by mass or more. Alternatively, it may be 90% by mass or less, 80% by mass or less, 70% by mass or less, 60% by mass or less, or 50% by mass or less.

[0032] It is preferable to set the proportion of (A) alkali-soluble polymer to the photosensitive resin composition to 90% by mass or less from the viewpoint of controlling the development time. On the other hand, it is preferable to set the proportion of (A) alkali-soluble polymer to the photosensitive resin composition to 10% by mass or more from the viewpoint of improving edge fusing resistance.

[0033] (B) Compounds having an ethylenically unsaturated double bond In this embodiment, (B) the compound having an ethylenically unsaturated double bond preferably contains a (meth)acryloxy group, and more preferably contains a compound having two or more functional ethylenically unsaturated double bonds. "A compound having two or more functional ethylenically unsaturated double bonds" means a compound having two or more ethylenically unsaturated double bonds in one molecule.

[0034] As compounds having an ethylenically unsaturated double bond, (meth)acrylate compounds are preferred. From the viewpoint of adhesion and flexibility of the resist pattern, for example, it is preferable that the compounds having an ethylenically unsaturated double bond include, for example, compounds having a bifunctional ethylenically unsaturated double bond and compounds having three or more functional ethylenically unsaturated double bonds.

[0035] Examples of compounds having a bifunctional ethylenically unsaturated double bond include alkyl di(meth)acrylates, 1,3-bis(meth)acryloyloxy-2-propanol, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, tricyclodecanol di(meth)acrylate, ethoxylated (hydrogenated) bisphenol A di(meth)acrylate, propoxylated (hydrogenated) bisphenol A di(meth)acrylate, and tetramethylene glycoxified (hydrogenated) bisphenol A di(meth)acrylate.

[0036] Among these, from the viewpoint of excellent adhesion to the substrate, it is preferable to include a compound containing a bisphenol A structure as a compound having an ethylenically unsaturated double bond.

[0037] Examples of commercially available compounds having a bifunctional ethylenically unsaturated double bond include NK esters (registered trademark) A-HD-N, A-NOD-N, A-DOD-N, A-NPG, 701A, A-200, A-400, A-600, A-1000, APG-200, APG-400, APG-700, A-PTMG65, A-DCP, ABE-300, A-BPE-4, A-BPE-10, A-BPE-20, HD-N, NOD-N, DOD-N, NPG, 701, 2G, 3G, 4G, 9G, and others. 14G, 23G, 9PG, DCP, BPE-80N, BPE-100, BPE-200, BPE-500, BPE-900, BPE-1300N, NK Oligo® UA-4200, UA-160TM, UA-290TM, UA-W2A, UA-4400, UA-122P, U-200PA (all manufactured by Shin Nakamura Chemical Industry Co., Ltd.), Light Acrylate® 3EG-A, 4EG-A, 9EG-A, 14EG-A, PTMGA-250, NP-A, MPD-A, 1.6HX-A, 1.9ND-A, DCP-A, BP-4EAL, BP-4PA, HPP-A, Light Ester G-201P (all manufactured by Kyoeisha Chemical Co., Ltd.), Funcryl (registered trademark) FA-124AS, FA-023M, FA-121M, FA-124M, FA-125M, FA-129AS, FA-137M, FA-220M, FA-222A, FA-240A, FA-240M, FA-320M, FA-3218M, FA-321A, FA-321M, FA-324A, FA-731A, FA-P240A, FA-P270A, FA-PTG9A, FA-PTG9M, FA-PTG28A, FA-PTG49A (all manufactured by Showa Denko Materials Co., Ltd.), DPGDA, HDDA, TPGDA, EBECRYL 145, EBECRYL 150, PEG400DA, EBECRYL 11, IRR 214-K, EBECRYL 130, EBECRYL PEG200DMA (manufactured by Daicel Ornex Co., Ltd.), SR212, SR213, SR230, SR238F, SR259, SR268, SR272, SR306H, SR344, SR349, SR508, CD560, CD561, CD564, SR601, SR602, SR610, SR833S, SR9003, SR9045, SR9209, SR205, SR206, SR209, SR210, SR214, SR231, SR239, SR248, SR252, SR297, SR348, SR480, CD540, CD541, CD542, SR603, SR644, SR9036 (manufactured by Arkema Co., Ltd.), KAYARAD (registered trademark) Examples include NPGDA, PEG400DA, FM-400, R-167, HX-220, HX-620, R-551, R-712, R-604, and R-684 (all manufactured by Nippon Kayaku Co., Ltd.).

[0038] Examples of compounds having three or more functional ethylenically unsaturated double bonds include trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, isocyanuric acid tri(meth)acrylate, pentaerythritol (tri / tetra)(meth)acrylate, ditrimethylolpropane (tetra / penta / hexa)(meth)acrylate, and dipentaerythritol (tetra / penta / hexa)(meth)acrylate.

[0039] Examples of commercially available compounds having three or more functional ethylenically unsaturated double bonds include NK esters (registered trademark) A-TMPT, A-TMPT-9EO, AT-20E, A-GLY-3E, A-GLY-9E, A-GLY-20E, A-9300, A-9200YN, A-TMM-3, A-TMM-3L, A-TMM-3LM-N, A-TMMT, ATM-35E, AD-TMP, A-DPH, and A-9550. , A-DPH-12E, TPOA-50, NK Oligo® UA-7100, UA-1100H, U-6LPA, UA-33H, U-10HA, U-10PA, U-15HA (all manufactured by Shin Nakamura Chemical Industry Co., Ltd.), Light Acrylate® TMP-A, cPE-3A, PE-4A, DPE-6A (all manufactured by Kyoeisha Chemical Co., Ltd.), FA-731A (manufactured by Showa Denko Materials K.K.), TMPTA, EBECRYL 160S, OTA 480, PETIA, PETRA, EBECRYL 40, PETA, EBECRYL 140, EBECRYL 1140, EBECRYL 1142, DPHA, EBECRYL 895, EBECRYL 896, EBECRYL TMPTMA (all manufactured by Daicel Ornex Co., Ltd.), SR351S, SR368, SR415, SR444, SR454, SR492, SR499, CD501, SR502, SR9020, D9021, SR9035, SR295, SR355, SR399, SR494, SR9041 (all manufactured by Arkema Co., Ltd.), KAYARAD (registered trademark) Examples include GPO-303, TMPTA, THE-330, TPA-330, PET-30, T-1420(T), RP-1040, DPHA, DPEA-12, D-310, and DPCA-20 (all manufactured by Nippon Kayaku Co., Ltd.).

[0040] The proportion of the compound having an ethylenically unsaturated double bond (B) to the total solid content of the photosensitive resin composition is preferably 30% by mass or more, and preferably 35% by mass or more, from the viewpoint of sensitivity, tackiness, and conformability. Furthermore, from the viewpoint of edge fusion, tackiness, and resolution, it is preferably 50% by mass or less, preferably 45% by mass or less, and preferably 42% by mass or less.

[0041] Furthermore, from the viewpoint of edge fusion properties, tackiness, and resolution, the ratio of the amount of (B) solid content of the compound having an ethylenically unsaturated double bond to the amount of (A) solid content of the alkali-soluble polymer contained in the photosensitive resin composition (i.e., the ratio of (B) solid content of the compound having an ethylenically unsaturated double bond / (A) solid content of the alkali-soluble polymer) is preferably 1.4 or less, preferably 1.3 or less, preferably 1.2 or less, and preferably 1.1 or less. The lower limit is preferably 0.7 or more, preferably 0.8 or more, preferably 0.9 or more, and preferably 1.0 or more.

[0042] The photosensitive resin composition of the present invention preferably has a mole count of ethylenically unsaturated double bonds per 100g of solid content of 0.1 to 0.3. Setting it to 0.1 or higher prevents the photosensitive resin component from leaching out from the cured resist pattern during the water washing step after development, thus preventing contamination of the water washing step. Setting it to 0.3 or lower prevents the cured resist pattern from chipping and falling off during the water washing step after development, thus preventing contamination of the water washing step.

[0043] The number of moles of ethylenically unsaturated double bonds per 100g of solids in the photosensitive resin composition is preferably 0.1 or more, more preferably 0.11 or more, more preferably 0.12 or more, and more preferably 0.13 or more. It is also preferably 0.3 or less, preferably 0.28 or less, preferably 0.25 or less, preferably 0.22 or less, preferably 0.20 or less, preferably 0.18 or less, and preferably 0.15 or less. More preferably, it is 0.1 or more and 0.25 or less, even more preferably 0.1 to 0.2, even more preferably 0.11 or more and 0.2 or less, and extremely preferably 0.11 or more and 0.15 or less.

[0044] (C) Sensitizer (C) Examples of sensitizers include pyrazoline derivatives, anthracene derivatives, triarylamine derivatives, oxazole derivatives, N-aryl-α-amino acid derivatives other than oxazole derivatives, aromatic ketone derivatives substituted with alkylamino groups, dialkylaminobenzoic acid ester derivatives, etc.

[0045] Examples of pyrazoline derivatives include 1-phenyl-3-(4-tert-butyl-styryl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-(4-(benzoxazol-2-yl)phenyl)-3-(4-tert-butyl-styryl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-phenyl-3-(4-biphenyl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-phenyl-3-(4-biphenyl)-5-(4-tert-octyl-phenyl)-pyrazoline, 1-phenyl-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline, and 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxy Examples include phenyl)-pyrazoline, 1-phenyl-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)-pyrazoline, 1-phenyl-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)-pyrazoline, and 1-phenyl-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)-pyrazoline.

[0046] Examples of anthracene derivatives include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, 2-ethyl-9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene, 9,10-dipentoxyanthracene, 9,10-dibutoxyanthracene, 9,10-diphenylanthracene, 2-ethyl-9,10-dibutoxyanthracene, 9-bromo-10-phenylanthracene, and 9-chloro-10-phenyl Examples include anthracene, 9-bromo-10-(2-naphthyl)anthracene, 9-bromo-10-(1-naphthyl)anthracene, 9-(2-biphenylyl)-10-bromoanthracene, 9-(4-biphenylyl)-10-bromoanthracene, 9-bromo-10-(9-phenanthryl)anthracene, 2-bromoanthracene, 9-bromoanthracene, 2-chloroanthracene, 9,10-dibromoanthracene, 9-(3-bromophenyl)-10-phenylanthracene, and 10-phenyl-9-anthraceneboronic acid. Among these, 9,10-diphenylanthracene and 10-phenyl-9-anthraceneboronic acid are preferred from the viewpoint of adhesion.

[0047] Examples of oxazole derivatives include 5-tert-butyl-2-[5-(5-tert-butyl-1,3-benzoxazole-2-yl)thiophen-2-yl]-1,3-benzoxazole and 2-[4-(1,3-benzoxazole-2-yl)naphthalene-1-yl]-1,3-benzoxazole.

[0048] Examples of N-aryl-α-amino acid derivatives include N-phenylglycine, N-methyl-N-phenylglycine, N-ethyl-N-phenylglycine, N-(n-propyl)-N-phenylglycine, N-(n-butyl)-N-phenylglycine, N-(2-methoxyethyl)-N-phenylglycine, N-methyl-N-phenylalanine, N-ethyl-N-phenylalanine, N-(n-propyl)-N-phenylalanine, N-(n-butyl)-N-phenylalanine, N-methyl-N-phenylvaline, N-methyl-N-phenylleucine, N-methyl-N-(p-tolyl)glycine, N-ethyl-N-(p-tolyl)glycine, and N-(n-pro Examples include N-(p-tolyl)glycine, N-(n-butyl)-N-(p-tolyl)glycine, N-methyl-N-(p-chlorophenyl)glycine, N-ethyl-N-(p-chlorophenyl)glycine, N-(n-propyl)-N-(p-chlorophenyl)glycine, N-methyl-N-(p-bromophenyl)glycine, N-ethyl-N-(p-bromophenyl)glycine, N-(n-butyl)-N-(p-bromophenyl)glycine, N,N'-diphenylglycine, N-methyl-N-(p-iodophenyl)glycine, N-(p-bromophenyl)glycine, N-(p-chlorophenyl)glycine, and N-(o-chlorophenyl)glycine. N-phenylglycine is particularly preferred due to its high sensitizing effect.

[0049] Examples of aromatic ketone derivatives substituted with alkylamino groups include benzophenone derivatives, specifically, alkylbenzophenone compounds such as benzophenone, 2-methylbenzophenone, 3-methylbenzophenone, or 4-methylbenzophenone; benzophenone compounds having halogen atoms such as 2-chlorobenzophenone, 4-chlorobenzophenone, or 4-bromobenzophenone; and carboxyl group derivatives such as 2-carboxybenzophenone, 2-ethoxycarbonylbenzophenone, benzophenonetetracarboxylic acid, or its tetramethyl ester. Examples include benzophenone compounds substituted with an alkoxycarbonyl group, bis(dialkylamino)benzophenone compounds such as 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(dicyclohexylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dihydroxyethylamino)benzophenone (preferably 4,4'-bis(dialkylamino)benzophenone compounds), or 4-methoxy-4'-dimethylaminobenzophenone, 4-methoxybenzophenone, 4,4'-dimethoxybenzophenone, etc. Among these, 4,4'-bis(diethylamino)benzophenone is preferred from the viewpoint of adhesion. (C) From the viewpoint of adhesion, the sensitizer preferably contains anthracene derivatives and benzophenone derivatives.

[0050] The above (C) sensitizer may be used alone or in combination of two or more.

[0051] (C) The amount of sensitizer added is preferably 0.01 to 1 part by mass, and more preferably 0.1 to 0.5 parts by mass, per 100 parts by mass of (A) alkali-soluble polymer.

[0052] (D) Polymerization inhibitors (D) Examples of polymerization inhibitors include phenol derivatives, hydroquinone derivatives, quinone derivatives, free radical polymerization inhibitors, nitrobenzene derivatives, phenothiazine derivatives, phenoxazine derivatives, and the like.

[0053] In particular, the photosensitive element of the present invention includes, as (D) polymerization inhibitors, a first phenolic polymerization inhibitor, a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, and a phenothiazine derivative.

[0054] Examples of phenolic compounds include p-methoxyphenol, hydroquinone, pyrogallol, tert-butylcatechol, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,5-di-tert-amylhydroquinone, 2,5-di-tert-butylhydroquinone, and 2,2'-methylenebis(4- Methyl-6-tert-butylphenol), bis(2-hydroxy-3-t-butyl-5-ethylphenyl)methane, triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3 [,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxyhydrocinnamamide), 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tris-(3,5-di-t-butyl-4 Examples include hydroxybenzyl)-isocyanurate, 4,4'-thiobis(6-tert-butyl-m-cresol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, styrene-phenols (e.g., Antege SP, manufactured by Kawaguchi Chemical Industries, Ltd.), tripenzylphenols (e.g., TBP, manufactured by Kawaguchi Chemical Industries, Ltd., phenols having 1 to 3 benzyl groups), and biphenols.

[0055] Examples of hydroquinone compounds include hydroquinone, methylhydroquinone, 2-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, and 2,6-di-tert-butylhydroquinone. Examples of quinone compounds include tert-butylbenzoquinone, 2,6-di-tert-butyl-1,4-benzoquinone, and 2,5-di-tert-butyl-1,4-benzoquinone.

[0056] Examples of free radical polymerization inhibitors include nitroso compounds such as p-nitrosophenol, nitrosobenzene, N-nitrosodiphenylamine, isononyl nitrite, N-nitrosocyclohexylhydroxylamine, N-nitrosophenylhydroxylamine, N,N'-dinitrosophenylenediamine, and their salts; and hindered amine compounds such as 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethyl-1-hydroxypiperidine, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, and 4-oxo-2,2,6,6-tetramethyl-1-oxypiperidine.

[0057] Examples of nitrobenzene compounds include nitrobenzene and 4-nitrotoluene. Examples of phenothiazine compounds include phenothiazine, 2,8-dioctylphenothiazine, 2-methoxyphenothiazine, 3-methoxyphenothiazine, 2-methylphenothiazine, 2-ethylphenothiazine, 2-trifluoromethylphenothiazine, 3,7-dibutylphenothiazine, 3,7-dioctylphenothiazine, 3,7-dicumylphenothiazine, 2-cyano-8-methoxyphenothiazine, 2-cyanophenothiazine, 2-bromophenothiazine, 2-chlorophenothiazine, bis-(α-dimethylbenzyl)phenothiazine, and bis-(α-methylbenzyl)phenothiazine.

[0058] (D) The polymerization inhibitor contains at least two phenolic polymerization inhibitors, specifically, a first phenolic polymerization inhibitor, a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, and a phenothiazine derivative.

[0059] By including a phenothiazine derivative, the NH group of the phenothiazine derivative and the OH group of the phenolic polymerization inhibitor form a hydrogen bond, preventing the phenolic polymerization inhibitor from volatilizing or diffusing from the photosensitive resin layer. Thus, a photosensitive element excellent in sensitivity and resolution and a method for forming a resist pattern that are not affected by manufacturing conditions and storage conditions determined by the film thickness can be provided.

[0060] (D) The ratio of the polymerization inhibitor to the total solid mass of the photosensitive resin composition is preferably 0.001% by mass to 10% by mass. From the viewpoint of very excellent adhesion and resolution, this ratio is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, still more preferably 0.01% by mass or more, even more preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more. On the other hand, from the viewpoints of less reduction in sensitivity and improvement in resolution, this ratio is preferably 10% by mass or less, more preferably 8% by mass or less, still more preferably 5% by mass or less, even more preferably 3% by mass or less, particularly preferably 2% by mass or less, and most preferably 1.5% by mass or less.

[0061] (D) The content of the polymerization inhibitor satisfies the following general formula (1): t 1 / 8 ≦ M p / (M1 + M2) ≦ t 1 / 2 (In the formula, t represents the film thickness of the photosensitive resin composition, and Mp, M1, and M2 are the contents (ppm) of the phenothiazine derivative, the first phenolic polymerization inhibitor, and the second phenolic inhibitor different from the first phenolic polymerization inhibitor, respectively.) It is preferable to satisfy. By adjusting the amount of polymerization inhibitor according to the film thickness so as to satisfy the above general formula (1), it is possible to provide a photosensitive element with superior sensitivity and resolution, and a method for forming a resist pattern.

[0062] As two types of phenolic polymerization inhibitors, it is even more preferable that the first and second phenolic polymerization inhibitors are p-methoxyphenol and 2,6-di-tert-butyl-p-cresol, which have a high synergistic effect in inhibiting polymerization.

[0063] By including both p-methoxyphenol and 2,6-di-tert-butyl-p-cresol, the efficiency of radical scavenging is further enhanced. 2,6-di-tert-butyl-p-cresol captures radicals to form phenoxy radicals, and then p-methoxyphenol acts as a hydrogen donor to reduce and regenerate 2,6-di-tert-butyl-p-cresol.

[0064] Preferably, the melting point of at least one of the first phenolic polymerization inhibitor and the second phenolic polymerization inhibitor is 100°C or lower, and more preferably 90°C or lower. This allows for uniform diffusion within the photosensitive resin composition during the heating step in which the support film coated with the photosensitive resin composition is heated to 90°C or higher, thereby providing a photosensitive element and a method for forming a resist pattern with superior sensitivity stability.

[0065] In this embodiment, a color-developing dye that develops color upon light irradiation may be included in the photosensitive resin composition layer. As color-developing dyes, for example, combinations of leuco dyes and halogen compounds are known. Examples of leuco dyes include tris(4-dimethylamino-2-methylphenyl)methane [leucocrystal violet] and tris(4-dimethylamino-2-methylphenyl)methane [leucomalachite green]. Examples of halogen compounds include amyl bromide, isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzal bromide, methylene bromide, tribromomethylphenylsulfone, carbon tetrabromide, tris(2,3-dibromopropyl)phosphate, trichloroacetamide, amyl iodide, isobutyl iodide, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, and hexachloroethane.

[0066] In this embodiment, additives such as plasticizers may be included in the photosensitive resin composition layer as needed. Examples of additives include phthalate esters such as diethyl phthalate, o-toluenesulfonamide, p-toluenesulfonamide, tributyl citrate, triethyl citrate, triethyl acetyl citrate, tri-n-propyl acetyl citrate, tri-n-butyl acetyl citrate, polypropylene glycol, polyethylene glycol, polyethylene glycol alkyl ether, and polypropylene glycol alkyl ether.

[0067] The thickness of the photosensitive resin composition layer is preferably 3 to 100 μm, with a more preferable upper limit of 50 μm. As the thickness of the photosensitive resin layer approaches 3 μm, the resolution improves, and as it approaches 100 μm, the film strength improves, so it can be appropriately selected depending on the application.

[0068] <Protective film> The photosensitive element of this embodiment may include a protective film in addition to the support film and the photosensitive resin composition layer. The protective film is laminated on the photosensitive resin composition layer side of the laminate of the support film and the photosensitive resin composition layer, and functions as a cover.

[0069] Since the adhesion force between the photosensitive resin composition layer and the protective film is sufficiently smaller than the adhesion force between the photosensitive resin composition layer and the support film, the protective film can be easily peeled off the photosensitive resin composition layer. For example, polyethylene film, polypropylene film, stretched polypropylene film, polyester film, etc., can be preferably used as the protective film, and among these, polypropylene film and polyethylene terephthalate film are more preferred as polyester films. Furthermore, a release layer may be provided on the surface of the protective film.

[0070] The thickness of the protective film is preferably 10 to 100 μm, and more preferably 10 to 50 μm. Examples of protective films include Alphan® EM-501, E-200, E-201F, FG-201, MA-411 (all manufactured by Oji F-Tex Co., Ltd.), Trefan® KW37, 2578, 2548, 2500, YM17S, Therapiel® PJ271, PJ111, HP2, PJ101, WZ, MDA, MFA, TK07, BKE, BX8A, SY (all manufactured by Toray Industries, Inc.), GF-18, GF-818, GF-858 (all manufactured by Tamapoly Co., Ltd.).

[0071] [Photosensitive element roll] The photosensitive element described above may be a long, elongated photosensitive element wound onto a core and used as a roll of photosensitive element.

[0072] [Method for forming a resist pattern] The method for forming a resist pattern using the photosensitive element according to this embodiment involves the following steps: A lamination process for stacking photosensitive elements onto a substrate; An exposure step for exposing the photosensitive resin composition layer of a photosensitive element; and A developing process for developing and removing unexposed areas of a photosensitive resin composition layer; The following are preferably included in this order:

[0073] In the lamination process, specifically, after peeling off the protective film from the photosensitive element, the photosensitive resin composition layer is heat-pressed onto the surface of a support (e.g., a substrate) using a laminator, and laminated once or multiple times. Examples of substrate materials include copper, stainless steel (SUS), glass, and indium tin oxide (ITO). The heating temperature during lamination is generally 40°C to 160°C. Heat pressing can be performed using a laminator equipped with rolls, or by repeatedly passing the laminate of the substrate and the photosensitive resin composition layer through the rolls several times. Heat pressing can be performed under reduced pressure if desired.

[0074] In the exposure process, the photosensitive resin composition layer is exposed to active light using an exposure machine. Exposure can be performed after peeling off the support, if desired. When exposure is performed through a photomask, the exposure amount is determined by the illuminance of the light source and the exposure time, and may be measured using a light meter. Direct imaging exposure may also be performed in the exposure process. In direct imaging exposure, exposure is performed directly on the substrate using a drawing device without using a photomask. A semiconductor laser with a wavelength of 350 nm to 410 nm or an ultra-high pressure mercury lamp is used as the light source. When the drawing pattern is controlled by a computer, the exposure amount is determined by the illuminance of the exposure light source and the moving speed of the substrate.

[0075] The light irradiation method used in the exposure process is preferably at least one method selected from projection exposure, proximity exposure, contact exposure, direct imaging exposure, and electron beam direct writing, and is more preferably performed by projection exposure or direct imaging exposure.

[0076] A heating step may be included between the exposure step and the development step. The heating temperature is preferably about 30°C to about 200°C, more preferably 30°C to 150°C, and even more preferably 35°C to 120°C. By performing this heating step, it is possible to improve resolution and adhesion. For heating, heating furnaces, constant temperature baths, hot plates, hot air dryers, infrared dryers, hot rolls, etc., can be used, using hot air, infrared, or far infrared methods.

[0077] The elapsed time from the exposure process to the heating process, or more precisely, the elapsed time from the point when exposure is stopped to the point when heating is started, is preferably 10 to 600 seconds, and more preferably 20 to 300 seconds. The elapsed time from the start of heating to the point when heating is stopped is preferably 1 to 120 seconds, and more preferably 5 to 60 seconds.

[0078] In the developing process, unexposed or exposed areas of the photosensitive resin composition layer after exposure are removed using a developing device and a developing solution. If there is a support film on the photosensitive resin composition layer after exposure, it is removed. Subsequently, the unexposed or exposed areas are developed and removed using a developing solution consisting of an alkaline aqueous solution to obtain a resist image.

[0079] As the alkaline aqueous solution, aqueous solutions of Na2CO3, K2CO3, tetramethylammonium hydroxide, etc. are preferred. The alkaline aqueous solution is selected according to the properties of the photosensitive resin composition layer, but an aqueous solution of Na2CO3 with a concentration of 0.2% to 2% by mass is generally used. Surface surfactants, defoamers, small amounts of organic solvents to promote development may be added to the alkaline aqueous solution. The temperature of the developer solution during the development process is preferably kept constant within the range of 20°C to 40°C.

[0080] In the development process, it is preferable to have a water washing step to remove the developer solution contained in the resist pattern after development. The washing water can be pure water, industrial water, or other types of water, and is selected according to the characteristics of the photosensitive resin composition layer. However, polyvalent metal salts such as MgSO4 may be added at a concentration of 0.001% to 1% by mass to improve resolution and the shape of the resist pattern. It is preferable to keep the temperature of the washing water in the water washing step constant within the range of 20°C to 40°C.

[0081] The resist pattern is obtained through the above process, but if desired, a further heating process can be performed at 60°C to 300°C. This heating process can improve the chemical resistance of the resist pattern. A heating furnace using hot air, infrared rays, or far-infrared rays can be used for the heating process.

[0082] To obtain a conductor pattern, a conductor pattern formation step may be performed after the development step or heating step, in which the substrate on which the resist pattern has been formed is etched or plated.

[0083] The method for manufacturing a conductor pattern involves, for example, using a metal plate or a metal film insulating plate as a substrate, forming a resist pattern using the resist pattern formation method described above, and then proceeding through a conductor pattern formation step. In the conductor pattern formation step, a conductor pattern is formed on the substrate surface (e.g., copper surface) exposed by development using a known etching method or plating method.

[0084] Furthermore, after manufacturing the conductor pattern using the method described above, a stripping step is performed to remove the resist pattern from the substrate using an aqueous solution that is more alkaline than the developer, thereby obtaining a wiring board (e.g., a printed wiring board) having a desired wiring pattern.

[0085] The alkaline aqueous solution used for stripping (hereinafter also referred to as "stripping solution") is not particularly limited, but an aqueous solution of NaOH or KOH with a concentration of 2% to 5% by mass, or an organic amine-based stripping solution, is generally used. A small amount of water-soluble solvent may be added to the stripping solution. Examples of water-soluble solvents include alcohol. The temperature of the stripping solution in the stripping process is preferably in the range of 40°C to 70°C.

[0086] In this embodiment, the photosensitive element can be used in the manufacture of printed circuit boards; the manufacture of lead frames for mounting IC chips; precision metal foil processing such as metal masks; the manufacture of packages such as ball grid arrays (BGAs) and chip-size packages (CSPs); the manufacture of tape substrates such as chip-on-film (COF) and tape automated bonding (TAB); the manufacture of semiconductor bumps; and the manufacture of partitions for flat panel displays such as ITO electrodes, address electrodes, and electromagnetic shields. Unless otherwise specified, the values ​​of each of the parameters mentioned above are measured in accordance with the measurement methods described in the examples below.

[0087] [Method for manufacturing a photosensitive element] The photosensitive element according to this embodiment, as described above, can be manufactured by the following method. In other words, the method for manufacturing a photosensitive element according to this embodiment is a method for manufacturing a photosensitive element comprising a support film, a photosensitive resin composition layer, and a protective film, and the following steps: A compounding step of preparing a photosensitive resin composition solution comprising (A) an alkali-soluble polymer, (B) a compound having an ethylenically unsaturated double bond, (C) a sensitizer, and (D) a first phenolic polymerization inhibitor, a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, a phenothiazine derivative, and a solvent. A coating process in which a photosensitive resin composition solution is applied to a support film. A heating process in which the coated support film is heated to 90°C or higher. This includes a lamination process in which protective films are layered.

[0088] This makes it possible to manufacture photosensitive elements with excellent sensitivity and resolution that are not affected by manufacturing or storage conditions determined by film thickness. As for specific methods, conventionally known methods can be adopted.

[0089] In the compounding process, a solvent is added to the above-mentioned (A) alkali-soluble polymer, (B) compound having an ethylenically unsaturated double bond, (C) sensitizer, and (D) first phenolic polymerization inhibitor, a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, and a phenothiazine derivative to prepare a photosensitive resin composition solution.

[0090] Suitable solvents include ketones, such as methyl ethyl ketone (MEK), and alcohols such as methanol, ethanol, and isopropyl alcohol. It is preferable to add the solvent to the photosensitive resin composition so that the viscosity of the photosensitive resin composition solution is 500 to 4000 mPa·sec at 25°C.

[0091] In the coating process, a photosensitive resin composition solution is applied onto the support film. For coating the photosensitive resin composition solution, for example, a bar coater or a roll coater can be used.

[0092] In the heating step, a support film coated with a photosensitive resin composition solution is heated to remove the solvent in the photosensitive resin composition solution by heating and distillation, thereby obtaining a photosensitive resin layer made of the photosensitive resin composition. Furthermore, the lower limit of the heating temperature of the coated support film is preferably about 70°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher. Heating to 90°C or higher accelerates the evaporation of the solvent contained in the photosensitive resin composition solution, thereby improving the production efficiency of the photosensitive element. The upper limit of the heating temperature is preferably about 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower. Maintaining a temperature of 120°C or lower prevents the thermal polymerization of the photosensitive resin composition from progressing.

[0093] In the lamination process, a photosensitive element can be manufactured by laminating a protective layer onto the photosensitive resin layer as needed.

[0094] In the method for producing the photosensitive element described above, it is preferable to further include a step for determining the polymerization inhibitor composition. The polymerization inhibitor composition determination step involves determining the assumed film thickness t' of the photosensitive resin composition layer in the photosensitive element to be manufactured, t' 1 / 8 ≤ M p / (M1+M2) ≤ t' 1 / 2 (In the formula, M p M1 and M2 are the content (ppm) of the phenothiazine derivative, the first phenolic polymerization inhibitor, and the second phenolic polymerization inhibitor, which is different from the first phenolic polymerization inhibitor, respectively. The composition ratio should satisfy the following conditions.

[0095] In the polymerization inhibitor composition determination process, by adjusting the amount of polymerization inhibitor according to the film thickness so as to satisfy the above general formula (1), a photosensitive element with superior sensitivity and resolution can be manufactured. [Examples]

[0096] Next, this embodiment will be described in more detail with reference to examples and comparative examples. However, this embodiment is not limited to the following examples unless it deviates from its essence. The physical properties in the examples were measured by the following methods.

[0097] [Preparation of evaluation samples] The evaluation samples were prepared as follows. <Fabrication of photosensitive elements> The components shown in Table 1 (where the numbers for each component indicate the amount (parts by mass) as solid content) and ethanol measured to a solid content concentration of 60% were thoroughly stirred and mixed to obtain a photosensitive resin composition solution. Details of the components shown in Table 1 are shown in Tables 2 and 3. A 16 μm thick polyethylene terephthalate film (Toray Industries, Inc., QS71) was used as a support film, and this solution was uniformly applied to its surface using a bar coater. The film was then dried in a 95°C dryer for the time specified below to form a photosensitive resin composition layer. Film thickness 5 μm: 30 seconds Film thickness 10 μm: 1 minute Film thickness 15 μm: 1 minute 30 seconds Film thickness 25μm: 2 minutes 30 seconds Film thickness 30 μm: 3 minutes Next, a photosensitive resin element was obtained by laminating an 18 μm thick stretched polypropylene film (manufactured by Oji F-Tex Co., Ltd., E-200) as a protective layer onto the surface of the photosensitive resin composition layer that did not have a polyethylene terephthalate film laminated on it.

[0098] <Substrate surface preparation> As an evaluation substrate for image quality, a 0.4 mm thick copper-clad laminate, consisting of 18 μm rolled copper foil layers, was cleaned on its surface with a 10 mass% H2SO4 aqueous solution.

[0099] <Laminate> While peeling off the polyethylene film (protective layer) of the photosensitive element, the photosensitive resin laminate was laminated onto a copper-clad laminate preheated to 50°C using a hot roll laminator (Asahi Kasei Corporation, AL-700) at a roll temperature of 105°C. The air pressure was set to 0.35 MPa and the lamination speed to 1.5 m / min.

[0100] <Exposure> Two hours after lamination, the photosensitive resin elements consisting of compositions 1 to 10 were exposed to a projection exposure machine (UX-44101SM, manufactured by Ushio Inc.) through a glass mask, while the photosensitive resin elements consisting of compositions 11 to 14 were exposed to a direct imaging exposure machine (FDi-3, manufactured by Oak Manufacturing Co., Ltd.) using a predetermined mask pattern for direct imaging (DI) exposure.

[0101] <Heating> The evaluation substrate, one minute after exposure, was heated for 30 seconds in a forced-air constant-temperature incubator (DKM600, manufactured by Yamato Scientific Co., Ltd.) set to 60°C.

[0102] <Developing> After peeling off the polyethylene terephthalate film (support film), development was performed using an alkaline developer (manufactured by Fuji Kiko Co., Ltd., for dry film) by spraying a 1% by mass Na2CO3 aqueous solution at 30°C for a predetermined time. The development spray time was set to twice the minimum development time, and the post-development water spray time was also set to twice the minimum development time. In this process, the shortest time required for the photosensitive resin layer in the unexposed areas to completely dissolve was defined as the minimum development time.

[0103] [evaluation] <Sensitivity stability> A photosensitive resin element three days after fabrication and an evaluation sample using a photosensitive resin element 30 days after fabrication were each exposed to light and developed. The optimal exposure amount (mJ) was defined as the amount at which the line width of the resulting cured resist pattern (L(line) / S(space) = 15 μm / 15 μm) was 15 μm, and evaluation was performed according to the following criteria. Excellent: Difference in optimal exposure is less than 10%. Good: The difference in optimal exposure is between 10% and less than 15%. Acceptable: Difference in optimal exposure is between 15% and less than 20%. Unacceptable: Difference in optimal exposure is 20% or more.

[0104] <Resolution> Three days after fabrication, evaluation samples using photosensitive resin elements were observed under a microscope in the area of ​​the independent circular hole opening pattern, and evaluated according to the following criteria. Excellent: The diameter of the minimum formed opening is less than film thickness × 0.25. Good: The diameter of the minimum formed opening is between film thickness × 0.25 and less than film thickness × 0.30. Acceptable: The diameter of the minimum formed opening is between film thickness × 0.30 and less than film thickness × 0.35. Not permitted: The diameter of the minimum formed opening is greater than or equal to the film thickness × 0.35.

[0105] The evaluation results for the samples used in the examples are shown in Table 1. Details of the components shown in Table 1 are shown in Tables 2 and 3.

[0106] [Table 1]

[0107] [Table 2]

[0108] [Table 3]

[0109] As is clear from Tables 1 to 3, the embodiments that met the requirements of the present invention showed good sensitivity stability and resolution.

[0110] In contrast, as shown in Table 1, when the requirements of the present invention were not met, satisfactory results were not obtained. Specifically, Comparative Examples 1 and 4, which did not contain phenothiazine as component (D), failed to achieve sensitivity stability. Comparative Examples 2, 3, 5, and 6, which contained only one phenolic polymerization inhibitor as component (D), failed to achieve resolution.

[0111] While embodiments of the present invention have been described above, the present invention is not limited thereto and can be modified as appropriate without departing from the spirit of the invention. [Industrial applicability]

[0112] By using the photosensitive element according to the present invention, the photosensitive element can be made to have excellent sensitivity stability and resolution, unaffected by coating and drying conditions or storage conditions, and can be widely used as a photosensitive element for forming resist patterns on printed circuit boards and the like.

Claims

1. A photosensitive element comprising a support film, a photosensitive resin composition layer containing a photosensitive resin composition formed on the support film, and a protective film, The above photosensitive resin composition comprises the following components: (A) Alkali-soluble polymer, (B) Compounds having an ethylenically unsaturated double bond, (C) Sensitizer, 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, and, (D) The polymerization inhibitor comprises a first phenolic polymerization inhibitor, a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, and a compound having a phenothiazine structure. A photosensitive element characterized in that at least one of the first phenolic polymerization inhibitor and the second phenolic polymerization inhibitor has a melting point of 100°C or less.

2. The photosensitive element according to claim 1, wherein the first phenolic polymerization inhibitor and the second phenolic polymerization inhibitor are 2,6-di-tert-butyl-para-cresol and 4-methoxyphenol.

3. The photosensitive element according to claim 1 or 2, wherein the (B) compound having an ethylenically unsaturated double bond includes a compound containing a bisphenol A structure.

4. The photosensitive element according to any one of claims 1 to 3, wherein the protective film is polypropylene or polyethylene terephthalate.

5. The photosensitive element according to any one of claims 1 to 4, wherein the (C) sensitizer comprises an anthracene derivative.

6. The photosensitive element according to any one of claims 1 to 5, wherein the (C) sensitizer comprises a benzophenone derivative.

7. The photosensitive element according to any one of claims 1 to 6, wherein the compound having the phenothiazine structure is at least one compound selected from the group consisting of phenothiazine, 2,8-dioctylphenothiazine, 2-methoxyphenothiazine, 3-methoxyphenothiazine, 2-methylphenothiazine, 2-ethylphenothiazine, 2-trifluoromethylphenothiazine, 3,7-dibutylphenothiazine, 3,7-dioctylphenothiazine, 3,7-dicumylphenothiazine, 2-cyano-8-methoxyphenothiazine, 2-cyanophenothiazine, 2-bromophenothiazine, 2-chlorophenothiazine, bis-(α-dimethylbenzyl)phenothiazine, and bis-(α-methylbenzyl)phenothiazine.

8. The following steps: A lamination step of laminating a photosensitive element according to any one of claims 1 to 7 onto a substrate, An exposure step of exposing the photosensitive resin layer of the photosensitive resin laminate, and A method for forming a resist pattern, comprising a developing step of developing and removing unexposed portions of the photosensitive resin layer.

9. A method for manufacturing a photosensitive element comprising a support film, a photosensitive resin composition layer, and a protective film, comprising the following steps: A compounding step of preparing a photosensitive resin composition solution comprising (A) an alkali-soluble polymer, (B) a compound having an ethylenically unsaturated double bond, (C) a sensitizer, a 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, and (D) a first phenolic polymerization inhibitor, a second phenolic polymerization inhibitor different from the first phenolic polymerization inhibitor, a compound having a phenothiazine structure, and a solvent. A coating step in which the photosensitive resin composition solution is applied to the support film, A heating step in which the coated support film is heated to 90°C or higher. Lamination process of layering protective films, Includes, A method for producing a photosensitive element, wherein at least one of the first phenolic polymerization inhibitor and the second phenolic polymerization inhibitor has a melting point of 100°C or less.

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