Curable resin composition, cured product and sacrificial film

Abstract

Provided is a curable resin composition containing an alkali-soluble resin (P) which satisfies condition (a) double bond equivalent of 600 or more and condition (b) acid value of 50-150 mg KOH / g, a monofunctional monomer (MA) having a cyclic skeleton, and, optionally, a monomer (MX) other than the monofunctional monomer (MA), in which the mass ratio of the alkali-soluble resin (P), the monofunctional monomer (MA), and the other monomer (MX) is 100:30-90:0-13.

Description

Curable resin composition, cured product, and sacrificial film

[0001] This invention relates to a curable resin composition, a cured product, and a sacrificial film.

[0002] Conventionally, the lift-off method has been widely used to form metal patterns. In the "lift-off method," a resist pattern is first formed on a substrate using a curable resin composition, and then a thin metal film is formed on the substrate having the resist pattern. Since the resist pattern functions as a sacrificial film, when the resist pattern is removed using a stripping solution after the metal film is formed, the thin metal film formed on the resist pattern can also be removed. In this way, the lift-off method allows for the formation of a metal pattern on a substrate without requiring an etching process (see, for example, Patent Document 1).

[0003] Furthermore, in the lift-off method, a reverse tapered shape (inverted triangle) is considered desirable for the resist pattern, where the lower part of the resist pattern (the part in contact with the substrate) is indented inward. This shape is also called a microgroove, and when forming a metal thin film, the metal thin film can easily penetrate between the resist patterns, allowing for the formation of a rectangular or tapered metal wiring pattern with good adhesion to the substrate. Moreover, since the reverse tapered resist pattern is easily peeled off from the substrate, it is less likely to adversely affect the shape of the metal wiring pattern when the resist pattern is peeled off (see, for example, Patent Document 2).

[0004] Japanese Patent Publication No. 2008-304719 Japanese Patent Publication No. 2010-15040

[0005] In recent years, as metal patterns have become smaller, there is a need to increase the thickness of metal wiring in devices with relatively high current loads, such as power semiconductors. Furthermore, in semiconductor manufacturing using the lift-off method, there is a growing trend to use less invasive solvents instead of highly soluble solvents (stripping solutions) such as amines when removing resist patterns (sacrificial films). In addition, cured resin compositions are required to exhibit high resolution and to be able to create a reverse-tapered (inverted triangular) cross-section of the resist pattern.

[0006] The present invention aims to solve the above-mentioned problems by providing a curable resin composition that exhibits high resolution, excellent selectivity for release agents and excellent cross-sectional shape when cured, as well as a cured product thereof and a sacrificial film.

[0007] The inventors diligently studied to solve the aforementioned problems. As a result, they discovered that the above problems could be solved by combining a specific polymer and monomer in a predetermined ratio, and thus completed the present invention.

[0008] <1> A curable resin composition comprising: an alkali-soluble resin (P) satisfying condition (a) a double bond equivalent of 600 or more and condition (b) an acid value of 50 to 150 mgKOH / g; a monofunctional monomer (MA) having a cyclic skeleton; and optionally another monomer (MX) other than the monofunctional monomer (MA), wherein the mass ratio of the alkali-soluble resin (P), the monofunctional monomer (MA), and the other monomer (MX) is 100:30 to 90:0 to 13. <2> The curable resin composition according to <1>, wherein the ClogP of the monofunctional monomer (MA) is 1.5 to 5.0. <3> The curable resin composition according to <1> or <2>, wherein the monofunctional monomer (MA) contains a photocurable group and / or a thermosetting group. <4> The curable resin composition according to any one of <1> to <3>, wherein the other monomer (MX) includes a photocurable group and / or a thermosetting group. <5> The curable resin composition according to any one of <1> to <4>, which is a negative-type photoresist material. <6> The curable resin composition according to any one of <1> to <5>, which is a lift-off negative-type photoresist material. <7> The curable resin composition according to <6>, wherein the thickness of the resist pattern formed is 5 μm or more. <8> A cured product obtained from the curable resin composition according to any one of <1> to <7>. <9> A sacrificial film obtained from the lift-off negative-type resist material according to <6> or <7>.

[0009] According to the present invention, it is possible to provide a curable resin composition that exhibits high resolution, excellent selectivity for release agents and excellent cross-sectional shape when cured, as well as a cured product thereof and a sacrificial film.

[0010] This is a schematic diagram showing the cross-sectional shape of the resist pattern.

[0011] The present invention will be described below, but the content of the present invention is not limited to the following description. Furthermore, throughout this specification, when "(meth)acrylic resin," etc. is referred to as "acrylic resin" or "methacrylic resin," etc., when "(meth)acrylic acid," etc. is referred to as "acrylic acid" or "methacrylic acid," etc., when "(meth)acrylate," etc. is referred to as "acrylate" or "methacrylate," etc., when "alkyl (meth)acrylate," etc. is referred to as "alkyl acrylate" or "alkyl methacrylate," etc., and when "(meth)acryloyl" is referred to as "acryloyl" or "methacryloyl." Furthermore, unless otherwise specified, when "alkyl group" is referred to as "alkyl group," linear, branched, and alicyclic alkyl groups are included. In addition, when a numerical range is indicated using "~", the values ​​at both ends of the range are included.

[0012] Curable Resin Composition The curable resin composition of this embodiment comprises an alkali-soluble resin (P) satisfying condition (a) a double bond equivalent of 600 or more and condition (b) an acid value of 50 to 150 mgKOH / g, a monofunctional monomer (MA) having a cyclic skeleton, and optionally other monomers (MX) other than the monofunctional monomer (MA) (hereinafter sometimes simply referred to as "other monomers (MX)"), wherein the mass ratio of the alkali-soluble resin (P), the monofunctional monomer (MA), and the other monomers (MX) is 100:30 to 90:0 to 13. The mass ratio is preferably 100:40 to 90:0 to 10, and more preferably 100:40 to 80:0 to 5.

[0013] The curable resin composition of this embodiment contains an alkali-soluble resin (P), exhibits high resolution, and has excellent cross-sectional shape when cured. Furthermore, the curable resin composition of this embodiment has excellent selectivity for release agents when cured, and can be removed (dissolved) with relatively low-invasive organic solvents such as acetone. In addition, the curable resin composition of this embodiment has high monomer hydrophobicity and does not easily show excessive solubility in developer after curing. For this reason, the pattern formed by the cured product of the curable resin composition of this embodiment has high adhesion to substrates, etc., and so-called pattern peeling is less likely to occur. Moreover, because the curable resin composition of this embodiment has excellent cross-sectional shape when cured and the pattern has high adhesion to substrates, etc., it can be suitably used for thick-film resist applications.

[0014] The curable resin composition of this embodiment may contain, in addition to the alkali-soluble resin (P) and monofunctional monomer (MA), other monomers (MX), polymerization initiators, light absorbers, and organic solvents. The resin composition of this embodiment can be used as a negative-type photoresist material, and is particularly suitable for use as a lift-off negative-type photoresist material.

[0015] <Alkali-soluble resin (P)> The alkali-soluble resin (P) is a polymer that satisfies condition (a) a double bond equivalent of 600 or more, and condition (b) an acid value of 50 to 150 mgKOH / g. These alkali-soluble resins (P) may be used individually or in combination of two or more types. Furthermore, it is preferable that the alkali-soluble resin (P) has condition (c) a ClogP of 0.5 to 3.0.

[0016] The double bond equivalent of the alkali-soluble resin (P) is 600 or more, preferably 800 or more, more preferably 1000 or more, and it is particularly preferable that it does not have double bond groups. Examples of "double bonds" include acryloyl groups, methacryloyl groups, vinyl groups, and allyl groups. Here, the "double bond equivalent" of the alkali-soluble resin (P) can be determined, for example, by "(mass of alkali-soluble resin (P) per 1 mol) / (number of ethylenically unsaturated groups per 1 mol)".

[0017] The acid value of the alkali-soluble resin (P) is 50 to 150 mg KOH / g, preferably 60 to 120 mg KOH / g, and more preferably 70 to 100 mg KOH / g, from the viewpoint of resist pattern developability. Here, the "acid value" of the alkali-soluble resin (P) represents the mass (mg) of potassium hydroxide required to neutralize the acid groups contained in 1 g of the target compound, and is a theoretical value calculated from the molecular weight and the number of functional groups (number of acid groups) per molecule based on the structure of the alkali-soluble resin (P). Specifically, the acid value of the alkali-soluble resin (P) is a value obtained by [moles of acid groups in the target compound (moles)] × [56.11 / amount of the target compound (g)].

[0018] The ClogP of the alkali-soluble resin (P) is preferably 0.5 to 3.0, more preferably 0.7 to 2.5, even more preferably 0.8 to 2.4, and particularly preferably 0.9 to 2.3, from the viewpoint of superior cross-sectional shape when the cured product is formed. Here, "CLogP" of the alkali-soluble resin (P) is an index representing the hydrophobicity of the chemical substance, and is a value obtained by calculation using PerkinElmer's ChemDraw Professional 21.0.0.

[0019] The weight-average molecular weight (Mw) of the alkali-soluble resin (P) is not particularly limited, but is preferably 5,000 to 20,000, more preferably 6,000 to 18,000, and particularly preferably 7,000 to 15,000, in terms of the developability of the resist pattern. The weight-average molecular weight (Mw) of the alkali-soluble resin (P) can be measured in polystyrene equivalent using gel permeation chromatography [Tosoh Corporation, catalog number: HLC-8320GPC, column: Tosoh Corporation, catalog number: TSKgel G-5000HXL and G-3000HXL linked together, solvent: tetrahydrofuran, flow rate: 1.0 mL / min].

[0020] Specific examples of alkali-soluble resins (P) include, for example, the following (meth)acrylic resins.

[0021] (Meth)acrylic resin) There are no particular limitations on the (meth)acrylic resin that can be used as the alkali-soluble resin (P), but examples include polymers containing the following units (a1-1), (a2-1), and (a3-1). The alkali-soluble resin (P) may contain one or more of the following units.

[0022] (In each formula, R1 represents a hydrogen atom or a methyl group, and in (a1-1), X 1 This represents a single bond, or a linear or branched alkylene group having 1 to 10 carbon atoms, in (a1-2), R 3 R represents a linear or branched alkyl group having 1 to 10 carbon atoms, which may have a hydroxyl group, in (a1-3), 4 (This indicates a group having a cyclic skeleton which may contain an oxygen atom.)

[0023] Unit (a1-1) has an acid group and a (meth)acryloyl group. In unit (a1-1), R 1 X represents a hydrogen atom or a methyl group. 1 This represents a single bond, or a linear or branched alkylene group having 1 to 10 carbon atoms. 1In terms of availability, a single bond is preferred. Examples of the unit (a1-1) include units derived from (meth)acrylic acid, etc. In terms of developability, a unit derived from methacrylic acid is preferred.

[0024] The unit (a1-2) has a linear or branched alkyl group or hydroxyalkyl group and a (meth)acryloyl group. In the unit (a1-2), R 1 represents a hydrogen atom or a methyl group, and R 3 represents a linear or branched alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group. Examples of R 3 include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, a hydroxymethyl group, a 2-hydroxyethyl group, etc. in terms of excellent developability and toughness of the cured product.

[0025] The unit (a1-3) has a group having a cyclic skeleton which may have an oxygen atom and a (meth)acryloyl group. In the unit (a1-3), R 1 represents a hydrogen atom or a methyl group, and R 4This indicates a group having a cyclic skeleton which may contain an oxygen atom. A “group having a cyclic skeleton which may contain an oxygen atom” may contain an oxygen atom in the cyclic skeleton itself, or it may contain an oxygen atom in a location other than the cyclic skeleton. Examples of cyclic skeletons include aromatic rings with 6 to 10 carbon atoms and heterocycles with 4 to 10 carbon atoms which contain an oxygen atom. Furthermore, examples of groups having a cyclic skeleton which may contain an oxygen atom that are likely to increase the hydrophobicity of the alkali-soluble resin (P) include phenoxymethyl group, phenoxyethyl group, phenoxyethylene glycol group, phenoxydiethylene glycol group, phenoxypolyethylene glycol group, and benzyl group, with phenoxyethyl group and tetrahydrofurfuryl being preferred. The units (a1-3) include phenoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, and benzyl methacrylate, with benzyl methacrylate, phenoxymethyl (meth)acrylate, and phenoxyethyl (meth)acrylate being particularly preferred. Examples include units derived from tetrahydrofurfuryl methacrylate and units derived from 2-phenoxyethyl methacrylate.

[0026] The alkali-soluble resin (P) may contain units other than those listed below (a1-1), (a2-1), and (a3-1). Examples of other units include those derived from N-cyclohexylmaleimide.

[0027] The mixing ratio (molar ratio) of each unit in the alkali-soluble resin (P) is not particularly limited, but from the viewpoint of easily satisfying conditions (a) and (b), and more preferably condition (c), the amount of unit (a1-1) can be 15 to 25, unit (a1-2) can be 20 to 30, unit (a1-3) can be 45 to 65, and the other units can be 10 to 30 per 100 moles of total alkali-soluble resin (P).

[0028] Specific examples of alkali-soluble resins (P) include the following:

[0029] From the viewpoint of developability and film-forming properties, the content of alkali-soluble resin (P) in the curable resin composition of this embodiment is preferably 40 to 80 parts by mass, more preferably 50 to 70 parts by mass, and particularly preferably 55 to 65 parts by mass, per 100 parts by mass of the solid content (mass of the curable resin composition minus the amount of solvent) of the curable resin composition.

[0030] <Monofunctional Monomer (MA)> The curable resin composition of this embodiment contains a monofunctional monomer (MA) having a cyclic skeleton. The cyclic skeleton of the monofunctional monomer (MA) may be either a monocyclic or polycyclic structure, for example, a cycloalkyl group having 1 to 20 carbon atoms. Furthermore, the cyclic skeleton such as a cycloalkyl group may have substituents such as a linear or branched alkyl group having 1 to 10 carbon atoms on the ring structure. Specifically, examples of the cyclic skeleton of the monofunctional monomer (MA) include monocyclic structures such as a cyclohexyl group and a 3,3,5-trimethylcyclohexyl group, and polycyclic structures such as an adamantane group, a 2-methyladamantane group, an isobornyl group, a dicyclopentanyl group, and a dicyclopentenyl group.

[0031] From the viewpoint of enhancing the hydrophobicity of the curable resin composition, the monofunctional monomer (MA) is preferably CLogP of 1.5 to 5.0, more preferably 2.0 to 5.0, even more preferably 3.0 to 5.0, and particularly preferably 4.0 to 5.0. These monofunctional monomers (MA) may be used individually or in combination of two or more.

[0032] The monofunctional monomer (MA) is preferably a group containing a photocurable group and / or a thermosetting group, as this makes it easier for the cured product to have a good shape. Examples of photocurable groups and / or thermosetting groups include, for example, acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, epoxy groups, oxetane groups, isocyanate groups, and maleimide groups, with acryloyl groups, methacryloyl groups, and maleimide groups being preferred in terms of reactivity (sensitivity). Furthermore, from the viewpoint of using the curable resin composition of this embodiment as a negative-type photoresist material, it is preferable that the functional group of the monofunctional monomer (MA) is a photocurable group.

[0033] Specific examples of the monofunctional monomer (MA) are not particularly limited as long as it is a monofunctional monomer having a cyclic skeleton. For example, (meth)acrylic monomers having a cyclic skeleton typified by the (meth)acrylic monomers described in the examples can be mentioned.

[0034] From the viewpoint of developability, the content of the monofunctional monomer (MA) in the curable resin composition of the present embodiment is 30 to 90 parts by mass, preferably 40 to 90 parts by mass, more preferably 40 to 80 parts by mass, and particularly preferably 50 to 70 parts by mass with respect to 100 parts by mass of the total amount of the alkali-soluble resin (P).

[0035] <Other monomers (MX)> The curable resin composition of the present embodiment optionally contains other monomers (MX). The other monomer (MX) is a monofunctional monomer having no cyclic skeleton or a polyfunctional monomer. When the other monomer (MX) is included, functions derived from the other monomer (MX) can be imparted to the curable resin composition. These other monomers (MX) may be used alone or in combination of two or more.

[0036] The other monomer (MX) preferably contains a group having a photocurable group and / or a thermosettable group. Examples of the photocurable group and / or thermosettable group include, for example, acryloyl group, methacryloyl group, vinyl group, allyl group, epoxy group, oxetane group, isocyanate group, maleimide group, etc. From the viewpoint of high reactivity, particularly reactivity by light, acryloyl group, methacryloyl group, and maleimide group are preferable.

[0037] When the other monomer (MX) is a monofunctional monomer, it is a monomer having no cyclic skeleton. Examples of the monofunctional other monomer (MX) having no cyclic skeleton include, for example, (meth)acrylic monomers having no cyclic skeleton.

[0038] When the other monomer (MX) is a polyfunctional monomer, the number of functional groups possessed by the other monomer (MX) is not particularly limited as long as it is 2 or more. Specific examples of the polyfunctional other monomer (MX) include, for example, dimethylol-tricyclodecane diacrylate (ClogP 4.7) and the like.

[0039] From the viewpoint of peelability, the content of the other monomer (MX) in the curable resin composition of the present embodiment is 0 to 13 parts by mass, preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, and even more preferably not containing the other monomer (MX) with respect to 100 parts by mass of the total amount of the alkali-soluble resin (P).

[0040] <Polymerization initiator> The curable resin composition of the present embodiment may contain a polymerization initiator. Here, the "polymerization initiator" is a compound that is activated by energy such as heat or light and initiates a polymerization reaction. Examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator. From the viewpoint of using in photolithography, it is preferable to use a photopolymerization initiator that generates radicals. These polymerization initiators may be used alone or in combination of two or more.

[0041] The above-mentioned photopolymerization initiator can be used without particular limitation as long as it is an initiator that absorbs active energy rays and generates radicals. Examples of the photopolymerization initiator include, for example, oxime esters, α-diketones; acyloins; acyloin ethers; thioxanthones; benzophenones; Michler's ketones; acetophenones; acylphosphine oxides; nones such as anthraquinone and 1,4-naphthoquinone; halogen compounds; peroxides and the like. These can be used alone or in combination of two or more. From the viewpoint of photocurability and the like, oxime esters are preferable as the photopolymerization initiator.

[0042] From the viewpoint of obtaining a good cross-sectional shape of the resist pattern, the content of the photopolymerization initiator in the curable resin composition of the present embodiment is preferably 1 to 5 parts by mass with respect to 100 parts by mass of the total amount of the resist solid content, and more preferably 2 to 4 parts by mass.

[0043] <Light Absorber> The curable resin composition of this embodiment may contain a light absorber from the viewpoint of the resist pattern shape. Here, the "light absorber" is a compound that absorbs light. As the light absorber, it is preferable to use an ultraviolet absorber from the viewpoint of the resist pattern shape. These light absorbers may be used individually or in combination of two or more types.

[0044] Examples of light absorbers include hydroxyphenyltriazine-based UV absorbers, benzophenone-based UV absorbers, and azobenzene derivative-based dyes and pigments.

[0045] The content of the light absorber in the curable resin composition of this embodiment is preferably 0.1 to 3 parts by mass, and more preferably 0.5 to 2 parts by mass, per 100 parts by mass of the total amount of resist solids, from the viewpoint of light sensitivity and resist pattern shape.

[0046] In this embodiment, the mass ratio (X / Y) of the total amount of photopolymerization initiator (X) to the total amount of light absorber (Y) in the curable resin composition is preferably 5 / 0.3 to 1 / 0.1, and more preferably 4 / 2 to 2 / 0.5, from the viewpoint of easily obtaining a good cross-sectional shape for the cured product. Furthermore, in this embodiment, the total amount (X + Y) of the photopolymerization initiator and light absorber in the curable resin composition is preferably 1 to 8 parts by mass, and more preferably 2.5 to 6 parts by mass, per 100 parts by mass of the total amount of resist solids, from the viewpoint of easily obtaining a good cross-sectional shape for the cured product.

[0047] <Other> The curable resin composition of this embodiment may contain additives such as organic solvents and surface modifiers as needed. Organic solvents are used for purposes such as viscosity adjustment. The organic solvents that can be used in the curable resin composition of this embodiment are not particularly limited as long as they can dissolve the above-mentioned components, but examples include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl amyl ketone, ethyl isoamyl ketone, diisobutyl ketone, and methylhexyl ketone; esters such as ethyl acetate, butyl acetate, methyl benzoate, and methyl propionate; ethers such as tetrahydrofuran, dioxane, and dimethoxyethane; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; alcohols such as ethyl alcohol and benzyl alcohol; aromatic hydrocarbons, aliphatic hydrocarbons, etc. The content of the organic solvent in the curable resin composition of this embodiment is preferably 50 to 150 parts by mass, more preferably 60 to 140 parts by mass, and particularly preferably 70 to 130 parts by mass, based on 100 parts by mass of the total amount of resist solids, from the viewpoint of easily increasing the thickness of the cured product.

[0048] [Method for Producing a Curable Resin Composition] The method for producing the curable resin composition of this embodiment is not particularly limited. An alkali-soluble resin (P) and a monofunctional monomer (MA), along with other monomers (MX), polymerization initiators, light absorbers, and other additives as needed, are placed in a stirring vessel and stirred and mixed to obtain a curable resin composition. Known stirrers and the like can be used for stirring and mixing. When other additives are added in the method for producing the curable resin composition, stirring is only required for a time sufficient for the additives to dissolve or disperse. These additives may be added to the stirring vessel together with the alkali-soluble resin (P) and monofunctional monomer (MA), or they may be added afterward.

[0049] 《Cured Product, Sacrificial Film》 The cured product of this embodiment is a cured product obtained from the curable resin composition described above, and can be obtained by curing the curable resin composition of this embodiment. The sacrificial film of this embodiment is a cured product of the curable resin composition described above, and in particular refers to a cured product obtained from a lift-off negative-type resist material. The method for curing the curable resin composition is not particularly limited and can be appropriately selected from commonly used methods. Examples of curing methods include irradiation with active energy rays and heating, but curing by active energy rays is preferred.

[0050] 《Method for forming resist patterns and method for forming metal patterns using the lift-off method》 A method for forming resist patterns using the curable resin composition of this embodiment and a method for forming metal patterns using the lift-off method will be described.

[0051] (Method for forming a resist pattern) The resist pattern forming method of this embodiment includes the steps of: applying the curable resin composition of this embodiment onto a substrate to form a resist film; irradiating the resist film with active energy rays in a patterned manner to obtain a resist film that has been cured in a patterned manner; and developing the resist film that has been cured in a patterned manner to form a resist pattern on the substrate.

[0052] In the process of forming the resist film described above, the substrate used is not particularly limited as long as it is a non-conductive substrate. Materials for forming a metal pattern on its surface, such as semiconductor device substrates made of silicon, gallium arsenide (GaAs), silicon carbide (SiC), gallium nitride (GaN), plastics, glass, etc., can be used.

[0053] The means for applying the curable resin composition of this embodiment onto the substrate are not particularly limited, and conventionally known methods can be used. Specifically, examples of means for applying the curable resin composition include rollers, roll coaters, spin coaters, curtain roll coaters, slit coaters, sprays, electrostatic coating, dipping coating, silk screen printing, spin coating, etc. In this process, after applying the curable resin composition of this embodiment onto the substrate, the organic solvent in the resist film may be removed by heating treatment or the like as needed.

[0054] In the process of obtaining a resist film cured in a patterned manner, the light source for the active energy rays irradiated onto the resist film can be a known light source. Examples of known light sources include (ultra-high pressure, high pressure, medium pressure, low pressure) mercury lamps, chemical lamps, carbon arc lamps, xenon lamps, metal halide lamps, tungsten lamps, and the like.

[0055] Furthermore, the active energy rays irradiated onto the resist film are not particularly limited, but examples include ultraviolet light, visible light, and laser light (near-infrared light, visible light laser, ultraviolet laser, etc.). As the active energy rays, ultraviolet light is preferred, and a mixture of three rays, i-rays (wavelength 365 nm), h-rays (wavelength 405 nm), and g-rays (wavelength 436 nm), is even more preferred.

[0056] In this process, heat treatments such as post-bake or pre-bake may be performed before or after irradiating the resist film with active energy rays.

[0057] In the process of forming a resist pattern, examples of developers used in the development process include alkaline developers containing triethylamine, diethanolamine, ammonia, sodium metasilicate, potassium metasilicate, sodium carbonate, tetraethylammonium hydroxide, tetramethylammonium hydroxyl (TMAH), etc. Examples of acidic developers include acidic developers such as acetic acid, formic acid, and hydroxyacetic acid. The concentration of the developer is usually in the range of 0.1 to 3% by mass, preferably 0.2 to 2% by mass. The development process is usually carried out at a temperature of 20 to 50°C for a period of 20 to 120 seconds.

[0058] The thickness of the resist pattern, that is, the thickness of the cured product or sacrificial film in this embodiment, is preferably 5 μm or more, more preferably 8 μm or more, and particularly preferably 10 μm or more, from the viewpoint of use in devices with relatively high current loads such as power semiconductors.

[0059] The cross-sectional shape of the resist pattern (resist film after development), that is, the cross-sectional shape of the cured product or sacrificial film in this embodiment, will be explained using Figure 1. Figure 1 is a schematic diagram showing the cross-sectional shape of the resist pattern. In Figure 1, the substrate 10, the resist pattern 20 provided on the substrate 10, and the mask 30 used when forming the resist pattern 20 are shown in cross-sectional view. Arrow X indicates the mask size, that is, the length in the width direction (horizontal direction of the paper) of the opening of the mask 30 corresponding to the resist pattern 20. Arrow Y indicates the length in the width direction of the top (exposure side) of the resist pattern 220, that is, 100% CD (CD: Critical Dimension). Arrow Z indicates the length in the width direction of the resist pattern 20 at a height of 10% from the bottom (substrate 10 side) of the resist pattern 20, with respect to the thickness of the resist pattern 20 (width in the vertical direction of the paper), that is, 10% CD. In terms of the cross-sectional shape of the resist pattern (resist film after development), it is preferable that the relationship between 100% CD and 10% CD is inversely tapered, satisfying the condition 100% CD > 10% CD. Furthermore, the ratio of 100% CD to 10% CD is preferably 100:50 to 95, and even more preferably 100:60 to 90.

[0060] Furthermore, the taper angle in the cross-sectional shape of the resist pattern 20 (the angle α (taper angle) at the intersection of the surface of the substrate 10 on which the resist pattern 20 is provided and the side surface of the resist pattern 20, as shown in Figure 1) is preferably less than 90°, and more preferably between 60° and 85°, from the viewpoint of the resolution of the metal pattern and the peelability of the resist pattern.

[0061] (Method for forming a metal pattern using the lift-off method) The method for forming a metal pattern using the lift-off method of this embodiment is performed immediately following the "step of forming a resist pattern" in the resist pattern forming method of this embodiment.

[0062] In other words, the metal pattern formation method using the lift-off method of this embodiment includes the steps of: applying the curable resin composition of this embodiment onto a substrate to form a resist film; irradiating the resist film with active energy rays in a patterned manner to obtain a resist film cured in a patterned manner; developing the resist film cured in a patterned manner to form a resist pattern on the substrate; forming a metal film over the entire surface of the substrate having the resist pattern; and performing a peeling treatment on the substrate surface to peel off the resist pattern and the metal film formed on the resist pattern to form a metal pattern.

[0063] In the process of forming a metal film, the type of metal used for the metal film and the means of forming the metal film are not particularly limited. For example, metal films of aluminum, copper, gold, ITO, tin oxide, tantalum, etc., can be formed by methods such as vapor deposition or sputtering. In this process, for example, UV ozone treatment or oxygen plasma treatment may be performed after the formation of the resist pattern in order to improve the adhesion between the metal film and the substrate before performing the vapor deposition or the like.

[0064] In the process of forming a metal pattern, known methods can be used for the stripping treatment to remove the resist pattern. Examples of stripping solutions that can be used in this treatment include organic solvents. In this process, the resist pattern and the metal film formed thereon can be removed by applying the stripping solution to the surface of the substrate and washing it off. Examples of organic solvents that can be used as stripping solutions include acetone, propylene glycol monomethyl ether acetate (PGMEA), 1,1,1-trichloroethane, methyl ethyl ketone, and methylene chloride. As the stripping solution used in the method of forming a metal pattern using the curable resin composition of this embodiment, relatively low-invasive organic solvents such as acetone and propylene glycol monomethyl ether acetate (PGMEA) are preferable because they cause less damage to the substrate. The stripping treatment is usually carried out by immersing the substrate in the stripping solution at a temperature of 15 to 80°C for 1 to 30 minutes. In particular, since the resist pattern using the curable resin composition of this embodiment has excellent solubility, the resist pattern can be removed using an organic solvent such as acetone at room temperature (around 25°C).

[0065] The metal patterns formed using the curable resin composition of this embodiment exhibit suppressed occurrence of chipping and short circuits, and also have excellent cross-sectional shape.

[0066] The present invention will be described in detail below using examples. However, the present invention is not limited to the following examples.

[0067] [Examples 1-13, Comparative Examples 1-2] Polymers P-1 to P'-1 were prepared using monomers derived from the compounds listed in Table 1. Each polymer was produced by the following procedure. <Polymers P-1 to P-5> Each monomer was charged into a glass flask equipped with a heating / cooling / stirring device, reflux condenser, and nitrogen inlet tube in the proportions listed in Table 1. After replacing the gas phase in the system with nitrogen, 2,2'-azobis(2,4-dimethylvaleronitrile) was added, the mixture was heated to 80°C, and the mixture was reacted at the same temperature for 6 hours to obtain a solution containing each polymer. <Polymer P'-1> Each monomer was charged into a glass flask equipped with a heating / cooling / stirring device, reflux condenser, and nitrogen inlet tube in the proportions listed in Table 1. After replacing the gas phase in the system with nitrogen, 2,2'-azobis(2,4-dimethylvaleronitrile) was added, the mixture was heated to 80°C, and the mixture was reacted at the same temperature for 6 hours, then heated to 100°C, and the mixture was reacted at the same temperature for 2 hours. After cooling to 40°C, 2-acryloyloxyethyl isocyanate was added to the reaction vessel, and the mixture was heated to 60°C and reacted at the same temperature for 6 hours to obtain a solution containing polymer P'-1.

[0068]

[0069]

[0070] Next, the components A to F in Tables 2 and 3 below were mixed to prepare the photosensitive compositions for the examples and comparative examples. The obtained compositions were then evaluated for pattern shape, resolution, and acetone peelability according to the method described later. The results are shown in the table below.

[0071]

[0072]

[0073] The structures of monomers (MA) and (MX) and the compounds C through F in the table are as follows:

[0074] <C: Oxime ester-based photopolymerization initiator> C-1: Irgacure OXE04 [Ciba Specialty Chemicals, trade name] C-2: Adeka Arcles NCI-831E [ADEKA, trade name] <D: UV absorber> D-1: 2,2'-dihydroxy-4,4'-dimethoxybenzophenone (SEESORB107 [Cypro Chemicals, trade name]) D-2: Tinuvin 479 [BASF, trade name] D-3: 4-(diethylamino)azobenzene <E: Surface modifier> E-1: Fz-2122 [Toray Dow Corning, trade name] <E: Organic solvent> F-1: Propylene glycol monomethyl ether acetate (PGMEA)

[0075] <Evaluation> <Pattern Shape Evaluation Method> Each photosensitive composition prepared in the examples and comparative examples was applied to each 10 cm x 10 cm square glass substrate using a spin coater to a finished film thickness of 10 μm, and left to stand at room temperature for 5 minutes. Then, the coating was heated on a 90°C hot plate for 2 minutes to completely remove the solvent. The obtained coating was then irradiated with light using a projection exposure machine and an L / S pattern mask (emission line: i-line, illuminance at 365 nm: 20 mW / cm²). 2 ). Subsequently, the resist pattern was formed by developing it for 60 seconds using a 2.38% TMAH (tetramethylammonium hydroxyl) aqueous solution (developer). The cross-section of the prepared resist pattern was observed using a scanning electron microscope (SEM) and the pattern shape was evaluated according to the following criteria: -Criteria for pattern shape- A: 100% CD value > 10% CD value C: 100% CD value ≤ 10% CD value

[0076] <Resolution Evaluation Method> Each photosensitive composition prepared in the examples and comparative examples was applied to a 10 cm x 10 cm square glass substrate using a spin coater to a finished film thickness of 10 μm, and left to stand at room temperature for 5 minutes. Then, the coating was heated on a 90°C hot plate for 2 minutes to completely remove the solvent. The obtained coating was then irradiated with light using a projection exposure machine and an L / S pattern mask (emission line: i-line, illuminance at 365 nm: 20 mW / cm²). 2). Subsequently, the resist pattern was formed by developing it with a 2.38% TMAH aqueous solution for 60 seconds. The L / S pattern of the prepared resist pattern was observed.

[0077] -Resolution Criteria- A: Minimum resolution is L / S = 20 / 20 (um) or less B: Minimum resolution is L / S = 20 / 20 (um) or more, and L / S = less than 30 / 30 (um) C: Minimum resolution is L / S = 30 / 30 (um) or more, or the pattern could not be created.

[0078] - Acetone Peelability Evaluation Method - Each photosensitive composition prepared in the examples and comparative examples was applied to a 10 cm x 10 cm square glass substrate using a spin coater to a finished film thickness of 10 μm, and left to stand at room temperature for 5 minutes. The coating was heated on a 90°C hot plate for 2 minutes to completely remove the solvent. The obtained coating was irradiated with light using a projection exposure machine (emission line: i-line, illuminance at 365 nm: 20 mW / cm²). 2 ). Subsequently, the film was developed using a 2.38% TMAH aqueous solution for 60 seconds and baked in a 100°C oven for 30 minutes to obtain a cured film. The obtained cured film was immersed in an acetone solution at 25°C. The time required for the cured film to peel off from the substrate was measured, and the peelability was evaluated according to the following criteria.

[0079] [Criteria for acetone-based peelability] A: Peeling time ≤ 2 minutes B: 2 minutes ≤ Peeling time < 5 minutes C: 5 minutes < Peeling time

[0080] The disclosure of Japanese Patent Application No. 2024-208048, filed on 29 November 2024, is incorporated herein by reference in its entirety. Furthermore, all documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated as being incorporated by reference.

[0081] 10: Substrate, 20: Resist pattern, 30: Mask

Claims

1. A curable resin composition comprising: an alkali-soluble resin (P) satisfying condition (a) having a double bond equivalent of 600 or more and condition (b) having an acid value of 50 to 150 mgKOH / g; a monofunctional monomer (MA) having a cyclic skeleton; and optionally other monomers (MX) other than the monofunctional monomer (MA), wherein the mass ratio of the alkali-soluble resin (P), the monofunctional monomer (MA), and the other monomer (MX) is 100:30 to 90:0 to 13.

2. The curable resin composition according to claim 1, wherein the ClogP of the monofunctional monomer (MA) is 1.5 to 5.

0.

3. The curable resin composition according to claim 1, wherein the monofunctional monomer (MA) comprises a photocurable group and / or a thermocurable group.

4. The curable resin composition according to claim 1, wherein the other monomer (MX) comprises a photocurable group and / or a thermocurable group.

5. The curable resin composition according to claim 1, wherein the negative-type photoresist material.

6. The curable resin composition according to claim 1, which is a negative-type photoresist material for lift-off.

7. The curable resin composition according to claim 6, wherein the thickness of the resist pattern formed is 5 μm or more.

8. A cured product obtained from the curable resin composition described in claim 1.

9. A sacrificial film obtained from the lift-off negative resist material according to claim 6 or 7.

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