Resin for photoresist, photoresist composition and cured product

Abstract

To provide a resin for photoresist which exhibits good adhesion to a metal substrate such as copper wiring after curing, can be stripped using a general organic solvent at room temperature when stripping a resist and can be cured at a low exposure dose, such as 100 mJ / cm2.SOLUTION: There is provided a resin for photoresist which contains 3 to 40 mass% of a structural unit derived from a monomer (a) represented by a predetermined general formula, 5 to 40 mass% of a structural unit derived from (meth)acrylic acid and 30 to 92 mass% of a structural unit derived from a monomer (c) represented by a predetermined general formula and has a weight average molecular weight of 3000 to 300000.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photoresist resin, a photoresist composition, and a cured product. In this specification, the term "photoresist" refers to a composition whose solubility in a developer changes upon irradiation with light, and is also referred to as a photoresist composition. The term "photoresist resin" refers to a resin used to produce a photoresist. [Background technology]

[0002] Photoresists are widely used in the manufacture of various parts, and are essential microfabrication materials in the manufacturing or processing of electronic parts, including image display devices such as televisions and image pickup elements used in digital cameras.

[0003] In recent years, with the miniaturization of electronic products, there is an even greater demand for miniaturization of modules and circuit boards. The miniaturization of circuit boards requires even finer wiring, making it essential to form finer patterns of photoresists for etching than ever before. For this reason, photoresist resins are required to have low exposure doses that can be cured with low exposure doses from an exposure light source.

[0004] In addition, with the miniaturization of wiring, there is a problem that the resist pattern of the hardened photoresist peels off during development or etching. This is thought to occur due to insufficient adhesion to the copper substrate, and there is a demand for further improvement in adhesion of the resist cured film. However, simply increasing adhesion can cause problems such as extremely long peeling times when peeling the cured film, or the generation of unpeeled areas during peeling. A known solution to this problem is to increase the temperature during peeling, but if the temperature is increased, the organic solvent in the stripping solution becomes more likely to volatilize, which can cause odor problems and have a negative impact on the working environment. For this reason, there is also a demand for the cured material to dissolve in the stripping solution at low temperatures.

[0005] Patent Document 1 discloses a photosensitive resin composition containing an alkali-soluble polymer, a photopolymerization initiator, and a compound having an ethylenic double bond in a predetermined ratio, which has a resist bottom width within a predetermined range when direct imaging exposure and development are performed under predetermined conditions. This photosensitive resin composition is said to have excellent adhesion to conductors such as copper wiring after plating.

[0006] Patent Document 2 discloses a negative radiation-sensitive resin composition containing a resin having a phenolic hydroxyl group that is soluble in alkali or an alkali-soluble acrylic resin, a radiation-sensitive radical polymerization initiator, an acid generator, and a compound having two or more ethylenically unsaturated double bonds and a specific linking group. The use of such a negative radiation-sensitive resin composition not only enables plating under alkaline conditions, but also enables the resist patterning to be stripped with a general organic solvent. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2017-223993 A [Patent Document 2] International Publication No. 2008 / 093507 Summary of the Invention [Problem to be solved by the invention]

[0008] However, when the alkali-soluble polymer specifically disclosed in Patent Document 1 is used, a strong alkaline stripping solution must be used in the stripping step, which poses a risk of corroding copper wiring, etc. In addition, the negative-type radiation-sensitive resin composition disclosed in Patent Document 2 requires long-term curing to increase adhesion to metal plates such as copper wiring, etc. In addition, the peeling process requires high temperatures of 50 to 70 degrees.

[0009] The object of the present invention is to provide a resist composition which exhibits good adhesion to metal substrates such as copper wiring after curing, can be peeled off using a general organic solvent at room temperature, and has an exposure dose of, for example, 100 mJ / cm. 2 The object of the present invention is to provide a photoresist resin which is cured at such a low exposure dose. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have found a photoresist resin that can achieve the above-mentioned object, and have completed the present invention. The gist of the present invention is as follows.

[0011] [1] A photoresist resin comprising 3 to 40 mass% of structural units derived from monomer (a) represented by the following formula (1), 5 to 40 mass% of structural units derived from (meth)acrylic acid (b), and 30 to 92 mass% of structural units derived from monomer (c) represented by the following formula (2), and having a weight average molecular weight of 3,000 to 300,000.

[0012] [ka]

[0013] (In formula (1), R 1 represents a hydrogen atom or a methyl group, and R 2 represents a linear alkylene group having 1 to 6 carbon atoms; R 3 represents a hydrogen atom or a methyl group, R 4 represents an alkyl group having 1 to 23 carbon atoms.

[0014] [ka]

[0015] (In formula (2), R 5 represents a hydrogen atom or a methyl group, X represents a single bond or an ester bond, R 6 represents a hydrocarbon group having 1 to 18 carbon atoms.

[0016] [2] A photoresist composition comprising the photoresist resin according to the above item [1], a photopolymerization initiator, and a polyfunctional monomer. [3] A cured product formed from the photoresist composition described in the above item [2]. Effect of the Invention

[0017] According to the present invention, after curing, the resist exhibits good adhesion to metal substrates such as copper wiring, can be peeled off using a general organic solvent at room temperature, and can be peeled off at an exposure dose of, for example, 100 mJ / cm. 2 It is possible to provide a photoresist resin that cures at such a low exposure dose. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] In this specification, a numerical range defined using the symbol "to" includes both the upper and lower limits of the range. For example, "2 to 4" means 2 or more and 4 or less. Furthermore, when a concentration or amount is specified, any higher concentration or amount can be associated with any lower concentration or amount. For example, when "2 to 10% by mass" and "preferably 4 to 8% by mass" are stated, the descriptions "2 to 4% by mass," "2 to 8% by mass," "4 to 10% by mass," and "8 to 10% by mass" are also included.

[0019] In addition, in this specification, "(meth)acrylate" refers to acrylate or methacrylate. Here, only one type of (meth)acrylate may be used, or two or more types may be used in combination. Therefore, when two or more types of (meth)acrylates may be present, "(meth)acrylate" refers to acrylate and / or methacrylate. Terms such as "(meth)acryloyl group" also have the same meaning as "(meth)acrylate".

[0020] Hereinafter, an embodiment of the present invention will be described.

[0021] [Photoresist resin] The photoresist resin according to the embodiment of the present invention contains 3 to 40 mass% of structural units derived from monomer (a) represented by formula (1) described below, 5 to 40 mass% of structural units derived from (meth)acrylic acid (b) described below, and 30 to 92 mass% of structural units derived from monomer (c) represented by formula (2) described below, and has a weight average molecular weight of 3,000 to 300,000. Each monomer component will be described below.

[0022] <Monomer (a)> The monomer (a) used in the embodiment of the present invention is represented by the following formula (1).

[0023] [ka]

[0024] (In formula (1), R 1 represents a hydrogen atom or a methyl group, and R 2 represents a linear alkylene group having 1 to 6 carbon atoms; R 3 represents a hydrogen atom or a methyl group, R 4 represents an alkyl group having 1 to 23 carbon atoms.

[0025] In formula (1), R 1 represents a hydrogen atom or a methyl group, and from the viewpoint of ease of curing, a hydrogen atom is preferred.

[0026] In formula (1), R 2 may be a linear alkylene group having 1 to 6 carbon atoms. The alkylene group may have 1 to 6 carbon atoms, but from the viewpoints of adhesion to metals and ease of availability of raw materials, it preferably has 1 to 3 carbon atoms, and particularly preferably has 2 carbon atoms.

[0027] In formula (1), R 3 represents a hydrogen atom or a methyl group. From the viewpoints of adhesion and curability (sensitivity) at a low exposure dose, a hydrogen atom is preferred.

[0028] In formula (1), R 4is an alkyl group having 1 to 23 carbon atoms. From the viewpoints of solubility in the stripping solution (removability) and ease of availability of raw materials, the alkyl group preferably has 1 to 18 carbon atoms, more preferably has 1 to 10 carbon atoms, and particularly preferably has 1 or 2 carbon atoms. The alkyl group may be linear or branched.

[0029] The monomer (a) may be used alone or in combination of two or more kinds. The content of the structural unit derived from the monomer (a) in the photoresist resin is 3% by mass to 40% by mass relative to the structural units derived from all monomers. More preferably, it is 10% by mass to 35% by mass, and particularly preferably, it is 10% by mass to 30% by mass. By setting it within these ranges, it is possible to obtain a cured product that is cured at a low exposure dose (i.e., has good sensitivity) and has good adhesion to a copper substrate. The content of the structural unit can be measured and calculated by GC / MS analysis performed under the conditions shown below. It can also be calculated based on the blending ratio of all monomers. Here, the content based on GC / MS analysis may deviate by about 10% from the content based on the blending ratio, so when using a value based on GC / MS analysis, the content of the structural unit can be determined taking this into consideration. The above points are the same for the monomers (b) and (c) described later. (GC / MS analysis method) Measurements can be carried out using a GC / MS device under the conditions shown below, and the proportions of the structural units can be calculated. Equipment name: JEОL JMS-Q1500GC Column: Agilent DB-1 (membrane thickness 0.25 mm) Carrier: He 1.5mL / min Split 1 / 30 Injection temperature: 300℃ Oven temperature: 100℃ (2min) - 310℃ (37min) 10℃ / min temperature increase Ionization current: 70 eV Ionization: EI Sample injection: 1 μL Pyrofoil: 590℃ (Japan Analytical Industry Co., Ltd.)

[0030] Monomer (a) can be produced, for example, by (1) subjecting (meth)acrylic acid and an alkanolamide to a dehydration esterification reaction in the presence of an acid catalyst, (2) subjecting a (meth)acrylic acid ester and an alkanolamide to an ester exchange reaction in the presence of an ester exchange catalyst, or (3) reacting acrylic acid chloride with an alkanolamide. Various conditions can be appropriately selected according to the type of catalyst used, the type of synthetic raw material, etc., in accordance with standard methods.

[0031] <(Meth)acrylic acid (b)> The (meth)acrylic acid (b) used in the embodiment of the present invention (hereinafter, may be referred to as "monomer (b)") is at least one selected from acrylic acid and methacrylic acid, with methacrylic acid being preferred in terms of copolymerization reactivity, solubility in an alkaline aqueous solution, and ease of availability. The content of the constitutional units derived from the (meth)acrylic acid (b) in the photoresist resin is 5 to 40 mass %, preferably 5 to 30 mass %, and more preferably 8 to 20 mass %, based on the constitutional units derived from all monomers. By setting the content within these ranges, a photoresist resin having good adhesion to substrates such as copper and solubility (removability) in a stripping solution can be obtained.

[0032] <Monomer (c)> The monomer (c) used in the embodiment of the present invention is a monomer represented by the following formula (2).

[0033] [ka]

[0034] (In formula (2), R 5 represents a hydrogen atom or a methyl group, X represents a single bond or an ester bond, R 6 represents a hydrocarbon group having 1 to 18 carbon atoms.

[0035] In formula (2), R 5is a hydrogen atom or a methyl group, and is not particularly limited, but is preferably a methyl group from the viewpoint of adhesion to a copper substrate.

[0036] In formula (2), X is a single bond or an ester bond and is not particularly limited, but is preferably an ester bond from the viewpoint of sensitivity.

[0037] In formula (2), R 6 is a hydrocarbon group having 1 to 18 carbon atoms. Examples of the hydrocarbon group include saturated or unsaturated aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. Specific examples of the hydrocarbon group having 1 to 18 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, a cyclohexyl group, an n-octyl group, a 2-ethylhexyl group, a phenyl group, a benzyl group, and a dicyclopentanyl group. From the viewpoints of adhesion to a copper substrate and solubility (removability) in a stripping solution, one or more selected from an n-butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, a dicyclopentanyl group, and a phenyl group are preferred.

[0038] The structural unit derived from the monomer (c) may be contained alone or in combination of two or more. When two or more types are combined, for example, it is preferable to combine a structural unit derived from one having a saturated aliphatic hydrocarbon group with one having a carbon number of 1 to 18 and a structural unit derived from one having an alicyclic hydrocarbon group.

[0039] The content ratio of the structural unit derived from the monomer (c) is 30 to 92% by mass, preferably 50 to 90% by mass, and more preferably 60 to 80% by mass, based on the structural units derived from all monomers. By setting the content in such a range, it is possible to achieve both the coatability of the monomer composition to the substrate, which will be described later, and the excellent adhesion of the photoresist resin to the copper substrate. In addition, when two or more structural units derived from the monomer (c) are combined, the ratio is not particularly limited and can be appropriately determined depending on the type of the structural unit. For example, when a structural unit (A) derived from a unit having a saturated aliphatic hydrocarbon group with 1 to 18 carbon atoms and a structural unit (B) derived from a unit having an alicyclic hydrocarbon group are combined, the mixing ratio (A / B) of A and B can be 80 / 20 to 55 / 45 on a mass basis.

[0040] The monomer (c) may be a commercially available product.

[0041] In the photoresist resin according to the embodiment, in addition to the monomers (a), (b) and (c) which are the above-mentioned structural units, a structural unit derived from another monomer copolymerizable therewith may be included. Examples of such other monomers include aromatic vinyl compounds and maleimide monomers. The structural units derived from these other monomers may be included alone or in combination of two or more. However, from the viewpoints of adhesion to a metal plate, peelability, curability at low exposure, etc., it is preferable that the resin does not include a structural unit derived from these other monomers. In other words, it is preferable that the total of the structural units derived from the above-mentioned monomer (a), (meth)acrylic acid (b) and monomer (c) is 100% by mass of the structural units derived from all monomers.

[0042] <Weight average molecular weight (Mw) of photoresist resin> The weight average molecular weight (Mw) of the photoresist resin according to the embodiment of the present invention is 3,000 to 300,000, preferably 5,000 to 100,000, and more preferably 5,000 to 50,000. The Mw can be determined in terms of polystyrene using gel permeation chromatography (GPC). If the Mw is less than 3,000, the cured product formed from the photoresist composition containing the photoresist resin may have insufficient adhesion to a copper substrate, and if the Mw is more than 300,000, the peelability of the photoresist may be deteriorated.

[0043] <Method of manufacturing photoresist resin> The photoresist resin according to the embodiment of the present invention can be produced, for example, by radical polymerization of the above-mentioned monomer (a), (meth)acrylic acid (b), and the above-mentioned monomer (c) (which may contain other monomers as required). Examples of the polymerization method include solution polymerization, suspension polymerization, and emulsion polymerization. Among these, solution polymerization is preferred because it is easy to adjust the weight average molecular weight of the photoresist resin to within the above-mentioned predetermined range. In solution polymerization, for example, a monomer composition containing the above-mentioned monomers (a), (b), and (c) (which may contain other monomers as required), a polymerization initiator, and a solvent is prepared, and the monomers are polymerized under predetermined conditions to obtain the photoresist resin. The polymerization initiator usable in the above-mentioned radical polymerization can be a known one. Examples of the polymerization initiator include organic peroxides and azo compounds. The polymerization initiator may be used alone or in combination of two or more.

[0044] Examples of organic peroxides include tert-butyl peroxy neodecanoate, tert-hexyl peroxy pivalate, methyl ethyl ketone peroxide, cyclohexanone peroxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, and dicumyl peroxide.

[0045] Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and 2,2'-azobis(2,4-dimethylvaleronitrile).

[0046] The amount of the polymerization initiator used can be appropriately set depending on the combination of monomers used, reaction conditions, etc. The method of adding the polymerization initiator and the monomer to the reactor is not particularly limited. For example, the total amount of the polymerization initiator and the monomer may be added to the reactor at once, or the polymerization initiator and the monomer may be added to the reactor in portions (for example, dropwise).

[0047] The solvent used in the solution polymerization is capable of dissolving the monomer and the polymerization initiator, and can be any solvent known in the field of photoresists. The solvent is, for example, at least one selected from the group consisting of methyl alcohol, ethyl alcohol, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, N,N-dimethylformamide, tetrahydrofuran, benzene, toluene, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether acetate, and is preferably propylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, or propylene glycol monomethyl ether acetate. The solvent may be used alone or in combination of two or more.

[0048] The total concentration of each monomer in the monomer composition is preferably 10 to 60% by mass, more preferably 20 to 50% by mass. If the total concentration is too low, monomers are likely to remain after polymerization, and the weight-average molecular weight of the resulting photoresist resin may decrease, whereas if the total concentration is too high, it may become difficult to control heat generation during polymerization.

[0049] The polymerization temperature can be appropriately set depending on the type of monomer, the type of polymerization initiator, the type of solvent, etc., and can be, for example, 50° C. to 120° C. The polymerization time can be appropriately set depending on the type of polymerization initiator, the polymerization temperature, etc. For example, when 2,2'-azobis(2,4-dimethylvaleronitrile) is used as the polymerization initiator and the polymerization temperature is 75° C., the polymerization time is, for example, about 4 hours.

[0050] The solution containing the photoresist resin obtained by solution polymerization may be used as it is for producing a photoresist composition. Alternatively, the photoresist resin may be isolated from the obtained solution containing the photoresist resin by a known means (e.g., solvent distillation, solid-liquid separation, etc.), and the isolated resin may be used for producing a photoresist composition.

[0051] [Photoresist composition] The photoresist composition according to the embodiment of the present invention includes the above-mentioned photoresist resin, photopolymerization initiator, and polyfunctional monomer. This photoresist composition is a composition whose solubility in a developer is reduced by light irradiation, that is, a negative photoresist composition in which a developed portion remains after exposure. The photoresist resin contained in the photoresist composition according to the embodiment of the present invention is as described above, but the content of the photoresist resin in the photoresist composition is not particularly limited and can be appropriately determined, and can be, for example, 1 to 5 mass% in terms of solid content. The solid content means a value excluding the solvent component contained in the resin solution when the photoresist resin is diluted with a solvent and used as a resin solution.

[0052] The photopolymerization initiator, the polyfunctional monomer, and other components that may be contained as necessary will be described below.

[0053] <Photopolymerization initiator> The photopolymerization initiator is not particularly limited, and photopolymerization initiators known in the field of photoresists can be used. Examples of such photopolymerization initiators include aromatic ketones, quinone compounds, benzoin compounds, benzoin ether compounds, benzyl derivatives, 2,4,5-triaryl imidazole dimers, glycine compounds, acridine derivatives, oxime esters, coumarin compounds, thioxanthone compounds, and acylphosphine oxide compounds. These may be used alone or in combination of two or more.

[0054] Examples of aromatic ketones include benzophenone, N,N,N,N'-tetramethyl-4,4'-diaminobenzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 4,4'-bis(dimethylamino)benzophenone (Michler's ketone), 4,4'-bis(diethylamino)benzophenone, and 4-methoxy-4'-dimethylaminobenzophenone.

[0055] Examples of the quinone compound include alkylanthraquinones and phenanthrenequinones.

[0056] Examples of the benzoin compound include benzoin and alkylbenzoins.

[0057] Examples of the benzoin ether compound include benzoin alkyl ether and benzoin phenyl ether.

[0058] An example of the benzyl derivative is benzyl dimethyl ketal.

[0059] An example of the glycine compound is N-phenylglycine.

[0060] An example of the acridine derivative is 9-phenylacridine.

[0061] Examples of oxime esters include 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime).

[0062] An example of the coumarin compound is 7-diethylamino-4-methylcoumarin.

[0063] An example of the thioxanthone compound is 2,4-diethylthioxanthone.

[0064] The acylphosphine oxide compound may, for example, be 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

[0065] The photopolymerization initiator is preferably at least one selected from the group consisting of aromatic ketones, quinone compounds, benzoin compounds, benzoin ether compounds, benzil derivatives, 2,4,5-triarylimidazole dimers, glycine compounds, acridine derivatives, oxime esters, coumarin compounds, thioxanthone compounds, and acylphosphine oxide compounds, more preferably aromatic ketones, quinone compounds, benzoin compounds, benzoin ether compounds, benzil derivatives, 2,4,5-triarylimidazole dimers, glycine compounds, acridine derivatives, oxime esters, coumarin compounds, thioxanthone compounds, or acylphosphine oxide compounds, still more preferably aromatic ketones, and particularly preferably 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone.

[0066] From the viewpoint of the curability of the photoresist composition, the content of the photopolymerization initiator is preferably 0.01 to 50 parts by mass, more preferably 1 to 40 parts by mass, and even more preferably 10 to 35 parts by mass, based on 100 parts by mass of the photoresist resin, where 100 parts by mass of the photoresist resin is the value calculated as the solid content, as described above.

[0067] <Polyfunctional Monomer> The polyfunctional monomer means a compound having two or more polymerizable functional groups. The polyfunctional monomer is preferably a compound having two or more olefinic double bonds, more preferably a compound having two or more (meth)acryloyl groups. Examples of the polyfunctional monomer include the following difunctional to hexafunctional monomers. The polyfunctional monomer may be, for example, one type selected from these difunctional to hexafunctional monomers, or two or more types may be used in combination.

[0068] Examples of bifunctional monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and 1,6-hexane glycol di(meth)acrylate. Examples of trifunctional monomers include trimethylolpropane tri(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, and pentaerythritol tri(meth)acrylate. An example of a tetrafunctional monomer is pentaerythritol tetra(meth)acrylate, an example of a pentafunctional monomer is dipentaerythritol penta(meth)acrylate, and an example of a hexafunctional monomer is dipentaerythritol hexa(meth)acrylate.

[0069] Among these polyfunctional monomers, tetrafunctional monomers, pentafunctional monomers, and hexafunctional monomers are preferred, and hexafunctional monomers are particularly preferred. Among the hexafunctional monomers, dipentaerythritol hexa(meth)acrylate is more preferred, and dipentaerythritol hexaacrylate is even more preferred.

[0070] From the viewpoint of the curability of the photoresist composition, the content of the polyfunctional monomer is preferably 10 to 500 parts by mass, more preferably 50 to 400 parts by mass, and even more preferably 100 to 350 parts by mass, per 100 parts by mass of the photoresist resin, where 100 parts by mass of the photoresist resin is the value calculated as the solid content, as described above.

[0071] <Other ingredients> The photoresist composition according to the embodiment of the present invention may contain other components in addition to the photoresist resin, the photopolymerization initiator, and the polyfunctional monomer, as long as the effects of the present invention are not impaired. Examples of other components include a solvent.

[0072] The solvent may be any solvent known in the field of photoresists. Examples of the solvent include methyl alcohol, ethyl alcohol, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, N,N-dimethylformamide, tetrahydrofuran, benzene, toluene, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether acetate. The solvent may be used alone or in combination of two or more.

[0073] From the viewpoint of coatability of the photoresist composition, the content of the solvent is preferably 40 to 95 mass %, more preferably 55 to 90 mass %, based on the total mass of the photoresist composition. If a solvent is contained in other components, this content is taken into consideration.

[0074] [Cured product] The cured product according to the embodiment of the present invention is formed from the photoresist composition. For example, the photoresist composition is applied to a circuit board to a desired thickness, and dried (pre-baked) under predetermined heating conditions to form a dried product (coating film). Then, the dried product is irradiated with active energy rays such as ultraviolet rays through a predetermined mask under predetermined conditions to obtain a cured product (cured film). In this case, the inclusion of the photoresist resin allows the composition to be cured with a lower active energy dose (i.e., exposure dose) than in the past. The curability due to such a low exposure dose can be evaluated by the method described in the Examples section below.

[0075] The cured product thus obtained contains the above-mentioned photoresist resin, and therefore has good adhesion to a metal plate such as a copper wiring, and can be peeled off from the metal plate with a general organic solvent at room temperature (has good releasability). The adhesion of such a cured product to a metal plate and the releasability of the cured product from the metal plate can be evaluated by the method described in the Examples section below. EXAMPLES

[0076] Hereinafter, the embodiment of the present invention will be described in detail based on examples.

[0077] (Polymerization Example 1: Photoresist Resin A1) In a 300 mL beaker, 16.5 g of methacrylic acid (b) (product name: MAA, manufactured by Kuraray Co., Ltd.), 84.0 g of n-butyl methacrylate (product name: monomer n-BMA, manufactured by Kuraray Co., Ltd.) and 42.0 g of dicyclopentanyl methacrylate (product name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.) as monomers (c), and 10.0 g of R 1 ~R 4The compound (monomer (a)-1) 22.5 g, which is shown in the (a)-1 column of Table 1, and propylene glycol monomethyl ether (product name: PM, manufactured by Daicel Corporation) 125 g were mixed and then cooled on ice, and 2,2'-azobis(2,4-dimethylvaleronitrile) (product name: V-65, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 7.5 g was added to obtain a monomer composition. Next, 100 g of propylene glycol monomethyl ether was charged into a 1 L separable flask equipped with a stirrer, a thermometer, a cooler, a dropping funnel, and a nitrogen inlet tube, and the flask was replaced with nitrogen to create a nitrogen atmosphere. The flask was heated to 75°C, and the above composition was dropped over 3 hours, and then reacted at 75°C for 4 hours to obtain a photoresist resin A1.

[0078] (Polymerization Example 2: Photoresist Resin A2) Photoresist resin A2 was obtained in the same manner as in Polymerization Example 1, except that the amount of 2,2'-azobis(2,4-dimethylvaleronitrile) added was changed to 3.5 g.

[0079] (Polymerization Example 3: Photoresist Resin A3) Photoresist resin A3 was obtained in the same manner as in Polymerization Example 1, except that the amount of 2,2'-azobis(2,4-dimethylvaleronitrile) added was changed to 20.0 g.

[0080] (Polymerization Example 4: Photoresist Resin A4) Photoresist resin A4 was obtained in the same manner as in Polymerization Example 1, except that the amounts of monomer (a)-1 used were changed to 45 g, methacrylic acid to 12.0 g, n-butyl methacrylate to 63.0 g, and dicyclopentanyl methacrylate to 30.0 g.

[0081] (Polymerization Example 5: Photoresist Resin A5) Photoresist resin A5 was obtained in the same manner as in Polymerization Example 1, except that the amounts of methacrylic acid, n-butyl methacrylate, and dicyclopentanyl methacrylate were changed to 5.0 g, 53.0 g, and 27.0 g, respectively.

[0082] (Polymerization Example 6: Photoresist Resin A6) Photoresist resin A6 was obtained in the same manner as in Polymerization Example 1, except that the amounts of methacrylic acid, n-butyl methacrylate, and dicyclopentanyl methacrylate were changed to 30.0 g, 37.0 g, and 18.0 g, respectively.

[0083] (Polymerization Example 7: Photoresist Resin A7) Photoresist resin A7 was obtained in the same manner as in Polymerization Example 1, except that acrylic acid was used instead of methacrylic acid.

[0084] (Polymerization Example 8: Photoresist Resin A8) A photoresist resin A8 was obtained in the same manner as in Polymerization Example 1, except that the amounts of Monomer (a)-1 were changed to 7.5 g, methacrylic acid to 18.2 g, n-butyl methacrylate to 94.1 g, and dicyclopentanyl methacrylate to 47.0 g.

[0085] (Polymerization Example 9: Photoresist Resin A9) R in formula (1) as monomer (a) 1 ~R 4 Photoresist resin A9 was obtained in the same manner as in Polymerization Example 1, except that the compound (monomer (a)-2) shown in the (a)-2 column of Table 1 was used instead.

[0086] (Polymerization Example 10: Photoresist Resin A10) R in formula (1) as monomer (a) 1 ~R 4 Photoresist resin A10 was obtained in the same manner as in Polymerization Example 1, except that the compound (monomer (a)-3) shown in the (a)-3 column of Table 1 was used instead.

[0087] (Polymerization Example 11: Photoresist Resin A11) R in formula (1) as monomer (a) 1 ~R 4 Photoresist resin A11 was obtained in the same manner as in Polymerization Example 1, except that the compound (monomer (a)-4) shown in the (a)-4 column of Table 1 was used instead.

[0088] (Polymerization Example 12: Photoresist Resin A12) R in formula (1) as monomer (a) 1 ~R 4 Photoresist resin A12 was obtained in the same manner as in Polymerization Example 1, except that the compound (monomer (a)-5) shown in the (a)-5 column of Table 1 was used instead.

[0089] (Polymerization Example 13: Photoresist Resin A13) R in formula (1) as monomer (a) 1 ~R 4 Photoresist resin A13 was obtained in the same manner as in Polymerization Example 1, except that the compound (monomer (a)-6) shown in the (a)-6 column of Table 1 was used instead.

[0090] (Polymerization Example 14: Photoresist Resin A14) R in formula (1) as monomer (a) 1 ~R 4 Photoresist resin A14 was obtained in the same manner as in Polymerization Example 1, except that the compound (monomer (a)-7) shown in the (a)-7 column of Table 1 was used instead.

[0091] (Polymerization Example 15: Photoresist Resin A15) R in formula (1) as monomer (a) 1 ~R 4 Photoresist resin A15 was obtained in the same manner as in Polymerization Example 1, except that the compound (monomer (a)-8) shown in the (a)-8 column of Table 1 was used instead.

[0092] (Polymerization Example 16: Photoresist Resin B1) Photoresist resin B1 was obtained in the same manner as in Polymerization Example 1, except that 4-hydroxymethacrylate was used instead of monomer (a).

[0093] (Polymerization Example 17: Photoresist Resin B2) Photoresist resin B2 was obtained in the same manner as in Polymerization Example 1, except that stearyl acrylate was used instead of monomer (a).

[0094] (Polymerization Example 18: Photoresist Resin B3) Photoresist resin B3 was obtained in the same manner as in Polymerization Example 1, except that N-propylacrylamide was used instead of monomer (a).

[0095] (Polymerization Example 19: Photoresist Resin B4) Photoresist resin B4 was obtained in the same manner as in Polymerization Example 3, except that the amounts of monomer (a)-1 used were changed to 90 g, methacrylic acid to 7.5 g, n-butyl methacrylate to 36 g, and dicyclopentanyl methacrylate to 16.5 g.

[0096] (Measurement of weight average molecular weight) The weight average molecular weights of the photoresist resins A1 to 15 and B1 to 4 were determined by gel permeation chromatography (GPC) under the following conditions. The measurement results are shown in Tables 2 and 3. The compounding ratios of Polymerization Examples 1 to 19 are also shown in Tables 2 and 3. Equipment: Tosoh Corporation, HLC-8220 Column: Shodex, LF-804 Standard material: polystyrene Eluent: THF (tetrahydrofuran) Flow rate: 1.0mL / min Column temperature: 40℃ Detector: RI (Differential Refractive Index Detector)

[0097] (Measurement of the content ratio of structural units derived from each monomer) Measurements were performed using a GC / MS device under the conditions shown below, and the proportions of the structural units were calculated. As a result, it was confirmed that the content of the structural units derived from each monomer in each production example was within 10% of the content based on the blend ratio. Equipment name: JEОL JMS-Q1500GC Column: Agilent DB-1 (membrane thickness 0.25 mm) Carrier: He 1.5mL / min Split 1 / 30 Injection temperature: 300℃ Oven temperature: 100℃ (2min) - 310℃ (37min) 10℃ / min temperature increase Ionization current: 70 eV Ionization: EI Sample injection: 1 μL Pyrofoil: 590℃ (Japan Analytical Industry Co., Ltd.)

[0098] <Examples 1 to 15 and Comparative Examples 1 to 4> [Preparation of Photoresist Composition] Photoresist compositions were prepared by mixing 10 g of each of the photoresist resins A1 to 15 and B1 to 4 (as a solution with a solid content of 15% by mass), 5.0 g of dipentaerythritol hexaacrylate ("Light Acrylate DPE-6A" manufactured by Kyoeisha Chemical Co., Ltd.), 0.5 g of a photopolymerization initiator (Irgacure 907, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone manufactured by BASF Corporation), and 40 g of propylene glycol monomethyl ether acetate and passing the mixture through a filter with a pore size of 0.5 μm.

[0099] [Evaluation of Adhesion] The prepared photoresist composition was applied onto a copper substrate by spin coating and dried at 90°C for 2 minutes (prebaked) to form a coating film having a thickness of 10 µm. The resulting coating film was exposed to 500 mJ / cm2 of an ultra-high pressure mercury lamp through a mask. 2 , 200mJ / cm 2 , 100mJ / cm 2 The coating was irradiated with ultraviolet light at an intensity of 1000 to form a cured film. The resulting cured film was subjected to a cross-cut test (based on the old JIS K5400) to evaluate adhesion. The adhesion was evaluated according to the following criteria based on the number of squares that remained without peeling out of 10 x 10 squares (100 squares). Note that if any part of the square was chipped, it was also considered to have peeled off. ◎: 100 squares remaining ○: 99 spaces remaining △: 90~98 spaces remaining ×: 89 or less squares remaining Adhesion that is acceptable for practical use can be evaluated as being "△", "◯" or "◎".

[0100] [Evaluation of peelability] In the above [Adhesion Evaluation], 100 mJ / cm 2 The cured film obtained under the conditions of curing at 40°C was immersed in acetone at room temperature for 10 minutes, then dried at 60°C for 2 minutes, and the weight change of the cured film was confirmed. The remaining weight of the cured film after peeling was evaluated according to the following criteria. ◎: Less than 10% ○: More than 10% and 30% or less △: More than 30% and less than 50% ×: More than 50%

[0101] The above evaluation results and the compounding ratios of the photoresist compositions of Examples 1 to 15 and Comparative Examples 1 to 4 are shown in Tables 4 and 5.

[0102] As shown in Tables 4 and 5, the photoresist compositions containing the specified photoresist resins were exposed to an exposure dose of 100 mJ / cm 2 It can be seen that the composition can be cured at such a low exposure dose, exhibits good adhesion to metal plates such as copper wiring after curing, and the cured product can be peeled off from the metal plate at room temperature using a common organic solvent.

[0103] [Table 1]

[0104] [Table 2]

[0105] [Table 3]

[0106] [Table 4]

[0107]

Table 5

Claims

1. A photoresist resin comprising 3 to 40 mass% of structural units derived from monomer (a) represented by the following formula (1), 5 to 40 mass% of structural units derived from (meth)acrylic acid (b), and 30 to 92 mass% of structural units derived from monomer (c) represented by the following formula (2), and having a weight average molecular weight of 3,000 to 300,000. 【Chemistry 1】 (In formula (1), R １ represents a hydrogen atom or a methyl group, R ２ represents a linear alkylene group having 1 to 6 carbon atoms; R ３ represents a hydrogen atom or a methyl group, R ４ represents an alkyl group having 1 to 23 carbon atoms. 【Chemistry 2】 (In formula (2), R ５ represents a hydrogen atom or a methyl group, X represents a single bond or an ester bond, R ６ represents a hydrocarbon group having 1 to 18 carbon atoms.

2. A photoresist composition comprising the photoresist resin according to claim 1, a photopolymerization initiator, and a polyfunctional monomer.

3. A cured product formed from the photoresist composition of claim 2.

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