Photosensitive resin composition

Abstract

To provide a photosensitive resin composition offering superior resistance to an etchant containing hydrofluoric acid or ammonium fluoride, and superior resolution and storage stability.SOLUTION: The present invention provides a photosensitive resin composition for forming a photosensitive resin layer included in a negative dry film resist for use in an etching method for etching a substrate with an etchant containing hydrofluoric acid or ammonium fluoride. The photosensitive resin composition at least comprises (A) an acid-modified epoxy (meth)acrylate, (B) a photopolymerization initiator, (C) a blocked-isocyanate compound, and (D) a styrene acryl copolymer.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a photosensitive resin composition used in an etching method using an etching solution containing hydrofluoric acid or ammonium fluoride.

Background Art

[0002] When forming a pattern on a substrate such as glass, silicon, titanium, etc. by etching, an etching solution containing hydrofluoric acid or ammonium fluoride may be used (hereinafter, the "etching solution containing hydrofluoric acid or ammonium fluoride" may be abbreviated as "hydrofluoric acid etching solution"). In such an etching process using a hydrofluoric acid etching solution, a negative-type photosensitive resin composition has conventionally been used as the photosensitive resin composition for forming a resist pattern on the substrate. Generally, a negative-type dry film resist in which a photosensitive resin layer containing a negative-type photosensitive resin composition and a support are laminated is used.

[0003] In an etching method using a hydrofluoric acid etching solution, for example, the surface of the photosensitive resin layer of a negative-type dry film resist in which the photosensitive resin layer and the support are laminated is bonded onto the substrate, and the photosensitive resin layer is exposed to actinic light through a photomask of a desired pattern to form a cured film of the photosensitive resin layer. Next, after peeling off the support, the unexposed portion (uncured portion) is removed by development, and a resist pattern composed of the cured photosensitive resin layer is formed on the substrate. Subsequently, the exposed substrate is sprayed with a hydrofluoric acid etching solution to perform an etching process for dissolving the substrate, and an etching pattern is formed on the substrate.

[0004] As photosensitive resin compositions capable of forming resist patterns resistant to hydrofluoric acid etching solutions, such as those that do not easily peel off the substrate during etching with hydrofluoric acid etching solutions, such photosensitive resin compositions (Patent Document 1) containing an alkali-soluble resin, a photopolymerization initiator, a photopolymerizable compound having an ethylenically unsaturated group, a blocked isocyanate compound, and a filler have been disclosed, as well as photosensitive resin compositions (Patent Document 2) containing an acid-modified epoxy acrylate, a photopolymerization initiator, a blocked isocyanate compound, and a filler. Although such fillers strengthen the film and are effective in improving resistance to hydrofluoric acid etching solutions, the fillers cause a loss of linearity in the resist pattern, resulting in a jagged resist pattern. As a result, the linearity of the images formed on the substrate by etching was also sometimes lost.

[0005] A negative-type dry film resist has been disclosed (Patent Document 3) as a photosensitive resin composition that exhibits excellent linearity of lines on a substrate, comprising a support, a first photosensitive resin layer, and a second photosensitive resin layer laminated in that order, wherein the first photosensitive resin layer contains at least an acid-modified epoxy (meth)acrylate, a photopolymerization initiator, a blocked isocyanate compound, and a filler, and the second photosensitive resin layer contains at least an acid-modified epoxy (meth)acrylate, a photopolymerization initiator, and a blocked isocyanate compound, but does not contain a filler. However, the resolution was sometimes insufficient due to the influence of the filler contained in the first photosensitive resin layer. On the other hand, when the first photosensitive resin layer did not contain a filler, the photosensitive resin layer peeled off prematurely, resulting in insufficient resistance to hydrofluoric acid etching solution.

[0006] A photosensitive resin composition containing a carboxyl group-containing binder resin, a photopolymerizable monomer, a photopolymerization initiator, and an organosilane compound has been disclosed as a photosensitive resin composition that exhibits excellent adhesion to glass substrates and good resistance to hydrofluoric acid etching solutions (Patent Document 4). However, the resolution was insufficient, and it was sometimes impossible to pattern fine lines with good linearity. In addition, when stored for a long period of time, the organosilane compound may react with the carboxyl groups of the binder resin, etc., which may reduce the elution properties. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2013-117682 [Patent Document 2] Japanese Patent Publication No. 2016-197226 [Patent Document 3] Japanese Patent Publication No. 2021-152622 [Patent Document 4] Japanese Patent Publication No. 2007-316247 [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a photosensitive resin composition that has good resistance to etching solutions containing hydrofluoric acid or ammonium fluoride, and exhibits excellent resolution and storage stability. [Means for solving the problem]

[0009] The above problems were solved by the following means.

[0010] A photosensitive resin composition for forming a photosensitive resin layer in a negative-type dry film resist used in an etching method in which a substrate is etched with an etching solution containing hydrofluoric acid or ammonium fluoride, characterized in that it contains at least (A) an acid-modified epoxy (meth)acrylate, (B) a photopolymerization initiator, (C) a blocked isocyanate compound, and (D) a styrene-acrylic copolymer. [Effects of the Invention]

[0011] The present invention provides a photosensitive resin composition that exhibits good resistance to etching solutions containing hydrofluoric acid or ammonium fluoride, and has excellent resolution and storage stability. [Modes for carrying out the invention]

[0012] The present invention will be described in detail below.

[0013] The photosensitive resin composition of the present invention contains (A) acid-modified epoxy (meth)acrylate (hereinafter sometimes referred to as "component (A)"). As component (A), an acid-modified unsaturated epoxy ester resin can be used, which is obtained by reacting an epoxy compound with an unsaturated carboxylic acid such as (meth)acrylic acid to obtain an unsaturated epoxy ester resin, and then further reacting the obtained unsaturated epoxy ester resin with an acid anhydride. The carboxyl groups and hydroxyl groups of component (A) undergo a crosslinking reaction with the (C) blocked isocyanate compound described later, thereby obtaining a photosensitive resin layer with good resistance to hydrofluoric acid etching solutions. Examples of the epoxy compound include phenol novolac type, cresol novolac type, bisphenol A type, bisphenol F type, trisphenol type, tetraphenol type, phenol-xylylene type, glycidyl ether type, or halogenated epoxy resins thereof. Examples of acid anhydrides that can be used include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, chlorendic anhydride, methyltetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic anhydride.

[0014] The acid value of component (A) affects the alkaline development speed, adhesion, etc. The acid value of component (A) (JIS K2501:2003) is preferably 40 to 120 mgKOH / g. If the acid value is less than 40 mgKOH / g, the development time may be prolonged, and if the acid value exceeds 120 mgKOH / g, the film-forming properties of the photosensitive resin composition may deteriorate.

[0015] Furthermore, the mass-average molecular weight of component (A) is preferably 3,000 to 15,000. If the mass-average molecular weight is less than 3,000, it may be difficult to form a film-like structure of the photosensitive resin layer before curing. On the other hand, if it exceeds 15,000, the solubility of the uncured portion of the photosensitive resin layer in the developer may decrease.

[0016] The (A) acid-modified epoxy (meth)acrylate contained in the photosensitive resin composition of the present invention may preferably be a commercially available product. For example, examples include KAYARAD® CCR-1235, ZAR-2000, ZFR-1401H, and UXE-3000 manufactured by Nippon Kayaku Co., Ltd., and Lipoxy® PR-300CP manufactured by Showa Denko K.K. These can be used alone or in combination of two or more.

[0017] The photosensitive resin composition of the present invention contains (B) a photopolymerization initiator (hereinafter sometimes referred to as "component (B)"). (B) The photopolymerization initiator may be an aromatic ketone such as benzophenone, 4,4′-bis(dimethylamino)benzophenone (Michler ketone), 4,4′-bis(diethylamino)benzophenone, 4-methoxy-4′-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propanone-1, etc.; 2-ethyl Anthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthaquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone, etc. Examples include non-benzoin compounds; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether; benzoin compounds such as benzoin, methyl benzoin, and ethyl benzoin; benzyl derivatives such as benzyl dimethyl ketal; 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer; acridine derivatives such as 9-phenylacridine and 1,7-bis(9,9′-acridinyl)heptane; N-phenylglycine, N-phenylglycine derivatives, and coumarin compounds. In the above 2,4,5-triarylimidazole dimer, the substituents on the aryl groups of the two 2,4,5-triarylimidazoles may be identical and give a symmetric compound, or they may be different and give an asymmetric compound.Furthermore, thioxanthone compounds and tertiary amine compounds may be combined, such as the combination of diethylthioxanthone and dimethylaminobenzoic acid. These can be used alone or in combination of two or more. In particular, the use of 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer alone or in combination with other photopolymerization initiators is preferred because it yields a highly sensitive photosensitive resin composition, and in this case, it is especially preferred that the 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer constitutes 80% by mass or more of the total amount of component (B).

[0018] The photosensitive resin composition of the present invention contains (C) a blocked isocyanate compound (hereinafter sometimes referred to as "component (C)"). Examples of the (C) blocked isocyanate compound include compounds in which the isocyanate group is protected by a blocking agent, and this compound is obtained by reacting the isocyanate group of the isocyanate compound with a blocking agent. The blocked isocyanate compound is stable at room temperature, but when heated, the blocking agent cleaves and isocyanate groups are generated. By performing heat treatment, a strong bond is formed by thermal crosslinking between the isocyanate group generated from the blocked isocyanate group in component (C) and the carboxyl group and hydroxyl group in component (A), and the resistance of the photosensitive resin layer to etching solutions containing hydrofluoric acid or ammonium fluoride is greatly improved.

[0019] Blocking agents include phenols such as phenol, cresol, p-ethylphenol, and p-tert-butylphenol; alcohols such as ethanol, butanol, ethylene glycol, methyl cellosolve, and benzyl alcohol; active methylenes such as diethyl malonate and ethyl acetoacetate; acid amides such as acetanilide and acetamide; other imides; amines; imidazoles; pyrazoles; ureas; carbamic acids; imines; oximes such as formaldehyde oxime, acetaldehyde oxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, and cyclohexanone oxime; mercaptans; sulfites such as sodium bisulfite and potassium bisulfite; and lactams. From the viewpoint of resistance to hydrofluoric acid etching solutions and improved resolution, pyrazole-based blocking agents are preferred, and dimethylpyrazole is particularly preferred.

[0020] Examples of isocyanate compounds include 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, xylylene diisocyanate, 1,6-hexamethylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-methylenebis(cyclohexyl isocyanate), trimethylhexamethylene diisocyanate, isophorone diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, lysine diisocyanate, methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate, 1,3-(isocyanatomethyl)cyclohexane, dimer acid diisocyanate, and prepolymers such as their adducts, biuretes, and isocyanurates. From the viewpoint of resistance to hydrofluoric acid etching solutions and improved resolution, 1,6-hexamethylene diisocyanate is preferred as the isocyanate compound, and its adduct, biuret, and isocyanurate forms are particularly preferred.

[0021] The photosensitive resin composition of the present invention contains a (D) styrene-acrylic copolymer (hereinafter sometimes referred to as "component (D)"). By using the styrene-acrylic copolymer, it is possible to improve the pattern resolution in the exposure and development processes, obtain a resist pattern with good adhesion to the substrate after heat (bake) treatment, and excellent resistance to hydrofluoric acid etching solution.

[0022] The (D) styrene-acrylic copolymer in the present invention is obtained by copolymerizing at least (i) styrene and its derivatives, (ii) (meth)acrylic acid, and may further be copolymerized with (iii) monomers having other ethylenically unsaturated groups.

[0023] The content of (i) styrene and its derivatives in the (D) styrene-acrylic copolymer is preferably 5 to 75% by mass, more preferably 10 to 67.5% by mass, and still more preferably 15 to 60% by mass, based on the total amount of (i) styrene and its derivatives, (ii) (meth)acrylic acid, and (iii) monomers having other ethylenically unsaturated groups, which are the copolymerization components of the (D) styrene-acrylic copolymer. If the content of (i) styrene and its derivatives is less than 5% by mass, the cured photosensitive resin layer is likely to swell in the developer, and meandering or deformation may occur in fine lines and dots. On the other hand, if the content of (i) styrene and its derivatives is more than 75% by mass, the unexposed portion of the photosensitive resin layer may not be completely removed in the developer, and etching may be inhibited.

[0024] The content of (ii)(meth)acrylic acid in the (D) styrene-acrylic copolymer is preferably 15 to 45% by mass, more preferably 20 to 40% by mass, and even more preferably 25 to 35% by mass, based on the total amount of (i) styrene and its derivatives, (ii)(meth)acrylic acid, and (iii) other monomers having ethylenically unsaturated groups, which are copolymer components of the (D) styrene-acrylic copolymer. If the content of (ii)(meth)acrylic acid is less than 15% by mass, the solubility of the unexposed portion of the photosensitive resin layer in the developer decreases, and the formation of the resist pattern by development may not proceed. On the other hand, if the content of (ii)(meth)acrylic acid is more than 45% by mass, the cured photosensitive resin layer becomes more prone to swelling in the developer, and meandering or deformation may occur in fine lines and dots. Furthermore, from the viewpoint of elution into the developer, (ii)(meth)acrylic acid is preferably methacrylic acid.

[0025] The photosensitive resin composition of the present invention may optionally contain components other than those listed above (A) to (D). Examples of such components include crosslinkable monomers, sensitizers, thermal polymerization inhibitors, plasticizers, colorants (dyes, pigments), photochromicants, thermal color inhibitors, defoamers, flame retardants, stabilizers, adhesion promoters, leveling agents, release accelerators, antioxidants, fragrances, thermosetting agents, water repellents, and oil repellents, and each of these can be contained in an amount of 0.01 to 20% by mass relative to the total content of components (A) to (D) in the photosensitive resin composition. These components can be used individually or in combination of two or more types.

[0026] The photosensitive resin composition of the present invention preferably does not contain (E) inorganic fillers. This makes it possible to obtain a photosensitive resin composition with high resolution. Examples of inorganic fillers include silica, talc, quartz, alumina, barium sulfate, barium titanate, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, titanium oxide, mica, etc. If the content of these exceeds 1.5% by mass relative to the total content of components (A) to (D) contained in the photosensitive resin composition, the resolution may decrease, so it is preferable to keep it at 1.5% by mass or less.

[0027] The photosensitive resin composition of the present invention preferably does not contain (F) organosilane compounds. This makes it possible to obtain a photosensitive resin composition with excellent storage stability. Examples of organosilane compounds include 3-(meth)acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-(2-aminoethylamino)propyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane. If the content of these compounds exceeds 1.0% by mass relative to the total content of components (A) to (D) contained in the photosensitive resin composition, the storage stability of the photosensitive resin composition may decrease, so it is preferable to keep it at 1.0% by mass or less.

[0028] The photosensitive resin composition of the present invention may optionally contain alcohols such as methanol, ethanol, n-propanol, 2-butanol, and n-hexanol; ketones such as acetone and 2-butanone; esters such as ethyl acetate, butyl acetate, n-amyl acetate, ethyl propionate, dimethyl phthalate, and ethyl benzoate; aromatic hydrocarbons such as toluene, xylene, benzene, and ethylbenzene; ethers such as tetrahydrofuran, diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and 1-methoxy-2-propanol; and solvents such as N,N-dimethylformamide and dimethyl sulfoxide, or mixtures thereof.

[0029] In the photosensitive resin composition of the present invention, the content of component (A) is preferably 35 to 90% by mass, and more preferably 45 to 80% by mass, relative to the total content of components (A) to (D) contained in the photosensitive resin composition. If the content of component (A) is less than 35% by mass, the film-forming properties may deteriorate. On the other hand, if the content of component (A) exceeds 90% by mass, the resistance to hydrofluoric acid etching solution may decrease.

[0030] In the photosensitive resin composition of the present invention, the content of component (B) is preferably 0.1 to 10% by mass, and more preferably 0.2 to 5% by mass, relative to the total content of components (A) to (D) contained in the photosensitive resin composition. If the content of component (B) is less than 0.1% by mass, the photopolymerization may be insufficient. On the other hand, if the content of component (B) exceeds 10% by mass, absorption on the surface of the resist increases during exposure, which may result in insufficient photocrosslinking within the photosensitive resin layer.

[0031] In the photosensitive resin composition of the present invention, the content of component (C) is preferably 5 to 35% by mass, and more preferably 10 to 30% by mass, relative to the total content of components (A) to (D) contained in the photosensitive resin composition. If the content of component (C) is less than 5% by mass, the resistance to hydrofluoric acid etching solution after heat (bake) treatment may be insufficient. On the other hand, if the content of component (C) exceeds 35% by mass, photocuring may be insufficient, and the resolution may decrease.

[0032] In the photosensitive resin composition of the present invention, the content of component (D) is preferably 2 to 19% by mass, more preferably 3 to 17% by mass, and even more preferably 4 to 15% by mass, relative to the total content of components (A) to (D) contained in the photosensitive resin composition. If the content of component (D) is less than 2% by mass, the adhesion between the photosensitive resin composition and the substrate may be insufficient, and the resistance to hydrofluoric acid etching solution may decrease. On the other hand, if the content of component (D) exceeds 19% by mass, the resolution may decrease.

[0033] Next, an etching method using the photosensitive resin composition of the present invention will be described in detail. First, a coating solution containing the photosensitive resin composition of the present invention is applied to a support and dried to form a photosensitive resin layer, thereby obtaining a negative-type dry film resist having a photosensitive resin layer on the support. Alternatively, the negative-type dry film resist may have a cover film attached to the photosensitive resin layer, so that the support, photosensitive resin layer, and cover film are in this order. The coating solution can be applied to the support using a roll coater, comma coater, gravure coater, air knife, die coater, bar coater, or the like.

[0034] A transparent film that transmits ultraviolet light is preferred as the support. For example, films such as polyethylene terephthalate, polypropylene, polyethylene, polyester, and polyvinyl alcohol can be used. In particular, polyethylene terephthalate film is advantageous in terms of lamination suitability, release suitability, high transmittance, and refractive index, and is very easy to use because it is inexpensive, does not become brittle, has excellent solvent resistance, and has high tensile strength. The thickness of the support is preferably 1 to 100 μm.

[0035] As the cover film, it is sufficient if it can peel off the uncured or cured photosensitive resin layer, and a resin film with high release properties is used. Examples include polyethylene film, polypropylene film, and polyethylene terephthalate film coated with a release agent such as silicone.

[0036] Next, the photosensitive resin layer is attached to the surface of the substrate. If a cover film is present, the cover film is removed before attaching the photosensitive resin layer to the surface of the substrate. The substrate according to the present invention is a substrate that undergoes etching with a hydrofluoric acid etching solution, and examples include glass, ceramic, silver oxide, silicon, germanium, tantalum, semiconductor substrate, quartz, titanium, etc.

[0037] One method for attaching a negative-type dry film resist to a substrate is lamination, and a general-purpose thermal laminator or vacuum laminator for printed circuit boards can be used. Lamination conditions such as nip pressure, transport speed, and roll temperature vary depending on the substrate used, but any conditions are acceptable as long as the film is attached without bubbles or unevenness.

[0038] After attaching a negative-type dry film resist to a substrate, a patterned exposure is performed on the photosensitive resin layer to cure the exposed areas. Specific exposure methods include contact exposure using a photomask, reflection image exposure, proximity method, and projection method, using a xenon lamp, high-pressure mercury lamp, low-pressure mercury lamp, ultra-high-pressure mercury lamp, UV fluorescent lamp, etc. as the light source; scanning exposure with SHG wavelength conversion according to the emission wavelength, using a laser such as a UV laser, He-Ne laser, He-Cd laser, argon laser, krypton ion laser, ruby ​​laser, YAG laser, nitrogen laser, dye laser, or excimer laser as the light source; or scanning exposure using a liquid crystal shutter or micromirror array shutter.

[0039] Next, alkaline development is performed to remove the unexposed areas of the photosensitive resin layer. For example, an aqueous solution of an inorganic alkaline compound can be used as the alkaline developer. Examples of inorganic alkaline compounds include carbonates and hydroxides of lithium, sodium, potassium, etc. The concentration of the inorganic alkaline compound in the alkaline developer is preferably 0.1 to 3% by mass, and a 0.1 to 3% by mass aqueous solution of sodium carbonate is preferably used as the alkaline developer. A small amount of surfactant, defoamer, solvent, etc., may also be added to the alkaline developer as appropriate. Methods for alkaline development include the dip method, spray method, paddle method, brushing, and scraping, with the spray method being the most suitable for removal speed. The processing temperature for alkaline development is preferably 15 to 35°C, and the spray pressure is preferably 0.02 to 0.3 MPa.

[0040] Next, a heat treatment (bake) is preferably performed. This improves the adhesion between the photosensitive resin layer and the substrate and enhances resistance to hydrofluoric acid etching solution. The heating temperature is preferably above the temperature at which the blocking agent of the (C) blocked isocyanate compound contained in the photosensitive resin composition of the present invention cleaves, preferably 90 to 250°C, and more preferably 110 to 200°C. If the temperature is below 90°C, the crosslinking reaction may proceed slowly, and if it exceeds 250°C, other components may decompose. The heating time is preferably 10 to 90 minutes.

[0041] Next, an etching process is performed on the exposed substrate by spraying it with hydrofluoric acid etching solution to dissolve the substrate and form an etching pattern on the substrate. After that, the resist pattern is peeled off from the substrate to obtain a substrate having the etching pattern. [Examples]

[0042] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0043] (Preparation of negative-type dry film resists having a photosensitive resin layer containing the photosensitive resin compositions of Examples 1-17 and Comparative Examples 1-2) The components shown in Table 1 were copolymerized to obtain styrene-acrylic copolymers (D-1) to (D-10). The units for the content of each component in Table 1 are parts by mass.

[0044] [Table 1]

[0045] Each component shown in Table 2 was mixed and diluted with 2-butanone to a component concentration of 50% to prepare coating solutions containing the photosensitive resin compositions of Examples 1-17 and Comparative Examples 1-2. The unit of each component content in Table 2 is parts by mass. Each of the obtained coating solutions was coated onto a highly transparent polyethylene terephthalate (PET) film (product name: FB40, 16 μm thick, manufactured by Toray Industries, Inc.) using a bar coater, and the solvent components were removed by drying at 80°C for 8 minutes to obtain each negative-type dry film resist having a photosensitive resin layer with a dry thickness of 15 μm on one side of the PET film.

[0046] [Table 2]

[0047] In Table 2, the components are as follows:

[0048] (A) Acid-modified epoxy (meth)acrylate (A-1) KAYARAD® UXE-3000 (product name, manufactured by Nippon Kayaku Co., Ltd., concentration 65% by mass, mass-average molecular weight: 10,000, acid value: 98 mg KOH / g) (A-2) KAYARAD ZAR-2000 (trade name, manufactured by Nippon Kayaku Co., Ltd., concentration 65% by mass, mass average molecular weight: 13,000, acid value: 98mgKOH / g)

[0049] (B) Photopolymerization initiator (B-1)2-(o-chlorophenyl)-4,5-diphenylimidazole dimer (B-2)4,4′-Bis(diethylamino)benzophenone

[0050] (C) Blocked isocyanate compound (C-1) Trixene BI7960 (product name, manufactured by GSI Creos Corporation, base: biuret compound of 1,6-hexamethylene diisocyanate, blocking agent: dimethylpyrazole, concentration 70% by mass) (C-2) Trixene BI7982 (product name, manufactured by GSI Creos Corporation, base: isocyanurate of 1,6-hexamethylene diisocyanate, blocking agent: dimethylpyrazole, concentration 70% by mass)

[0051] (E) Inorganic filler (E-1) Talc (Product name: SG95, manufactured by Nippon Talc Co., Ltd., average particle size 2.5 μm)

[0052] (F) Organosilane compounds (F-1) Vinyltriethoxysilane

[0053] (G) Isocyanate compound (G-1) Duranate® 22A-75P (product name, manufactured by Asahi Kasei Corporation, base: biuret compound of 1,6-hexamethylene diisocyanate, concentration 75% by mass)

[0054] (H) Acrylic copolymer Copolymer obtained by copolymerizing (H-1) methyl methacrylate:methacrylic acid = 75:25 (parts by mass)

[0055] The storage stability of the obtained negative-type dry film resist was evaluated as follows. The evaluation results are shown in Table 2.

[0056] (Storage stability) The sensitivity of negative-type dry film resists immediately after preparation and after storage at room temperature (25°C) for one month was compared using a transmission step wedge T2115 (manufactured by Stauffa). A difference of 1 stop or less between the sensitivity immediately after preparation and the sensitivity after one month of storage was marked with ○, a difference of more than 1 stop but within 5 stops was marked with △, and a difference of more than 5 stops was marked with ×. In this invention, a difference of 5 stops or less between the sensitivity immediately after preparation and the sensitivity after one month of storage was considered to be practical.

[0057] Next, the negative-type dry film resists from Examples 1-17 and Comparative Examples 1-2 obtained above were heat-pressed onto a 2 mm thick glass substrate at 100°C, with the surface of the photosensitive resin layer in contact with the glass substrate. Then, the photosensitive resin layer was exposed to a high-pressure mercury lamp through a photomask (line / space = 500 μm / 50 μm). After exposure, the substrate was left at room temperature for 10 minutes, then the PET film of the negative-type dry film resist was peeled off, and a 1% by mass aqueous sodium carbonate solution was sprayed onto the exposed surface of the photosensitive resin layer at a temperature of 30°C and a spray pressure of 0.1 MPa to remove the unexposed areas and form a resist pattern. After that, the resist pattern was washed with water, dried, and then baked at 150°C for 30 minutes to obtain a glass substrate with a resist pattern.

[0058] The resolution and resistance to hydrofluoric acid etching of the resist pattern formed on the surface of the glass substrate were evaluated as follows. The evaluation results are shown in Table 2.

[0059] (resolution) Resist patterns with a line / space of 500 μm / 50 μm were observed under a microscope and evaluated as follows: ○ indicates no swelling or distortion of the resist pattern due to developer penetration and no developer residue whatsoever; △ indicates slight swelling or distortion of the resist pattern due to developer penetration, or slight developer residue, but not a practical problem; and × indicates clear swelling or distortion of the resist pattern due to developer penetration, or significant developer residue, which poses a practical problem.

[0060] (Resistance to hydrofluoric acid etching solution) A glass substrate with a resist pattern was immersed for 30 minutes in a hydrofluoric acid etching solution (25°C) prepared by mixing 4 mol / kg aqueous ammonium fluoride and 2 mol / kg sulfuric acid in a 1:1 ratio (parts by mass). During this process, samples were evaluated as follows: ○ if the resist pattern did not peel off and an etching pattern was successfully formed on the substrate; △ if the resist pattern partially peeled off but an etching pattern was formed on the substrate at a level that was practically acceptable; and × if the resist pattern peeled off partially or completely, preventing the formation of the desired etching pattern on the substrate.

[0061] Examples 1 to 17 all demonstrated resolution and resistance to hydrofluoric acid etching solutions that were practically acceptable.

[0062] Comparative Example 1, which did not contain (C) a blocked isocyanate compound and contained (G) an isocyanate compound, was unable to dissolve the unexposed areas of the DFR and was unable to form a resist pattern on the substrate, and therefore could not etch the glass substrate.

[0063] Comparative Example 2, which did not contain (D) styrene-acrylic copolymer and contained (H) acrylic copolymer, showed significant swelling of the resist pattern due to penetration of the developer after the development process. Furthermore, when the glass substrate was etched with hydrofluoric acid etching solution, peeling of the resist pattern occurred prematurely, making it impossible to obtain the desired etching pattern. [Industrial applicability]

[0064] The photosensitive resin composition of the present invention can be used as a resist when etching various substrates using an etching solution containing hydrofluoric acid or ammonium fluoride.

Claims

[Claim 1] A photosensitive resin composition for forming a photosensitive resin layer in a negative-type dry film resist used in an etching method in which a substrate is etched with an etching solution containing hydrofluoric acid or ammonium fluoride, wherein the photosensitive resin composition contains at least (A) an acid-modified epoxy (meth)acrylate, (B) a photopolymerization initiator, (C) a blocked isocyanate compound in which the isocyanate group is protected with a pyrazole-based blocking agent, and (D) a styrene-acrylic copolymer, characterized in that the content of component (A) is 35 to 90% by mass of the total content of components (A) to (D), and the content of component (D) is 2 to 19% by mass of the total content of components (A) to (D).

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