Photosensitive resin composition and method for manufacturing a circuit board using the same

Abstract

To provide a photosensitive resin composition that can form resin patterns with high resolution. [Solution] A photosensitive resin composition comprising (A) component: a resin having a phenolic hydroxyl group, (B) component: a compound having a methylol group or an alkoxyalkyl group, and (C) component: a photoacid generator, wherein (A) component contains a resin having structural units derived from hydroxystyrene.

Description

[Technical Field]

[0001] This disclosure relates to a photosensitive resin composition and a method for manufacturing a circuit board using the same. [Background technology]

[0002] In the manufacture of semiconductor devices or printed circuit boards, for example, negative-type photosensitive resin compositions are used to form fine patterns. In this method, a photosensitive layer (coating film) is formed on a substrate (a chip in the case of a semiconductor device, or a substrate in the case of a printed circuit board) by coating the photosensitive resin composition, and the exposed areas are cured by irradiating them with active light through a predetermined pattern. Furthermore, by selectively removing the unexposed areas using a developer, a resin pattern, which is a cured film of the photosensitive resin composition, is formed on the substrate. Therefore, the photosensitive resin composition is required to have excellent sensitivity to active light, the ability to form fine patterns (resolution), etc. For example, Patent Document 1 discloses a photosensitive resin composition with excellent resolution.

[0003] Furthermore, Patent Document 2 discloses a method for manufacturing a circuit board having an even finer conductor pattern using a photosensitive resin composition with excellent resolution. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2015 / 046522 [Patent Document 2] International Publication No. 2016 / 084855 [Overview of the project] [Problems that the invention aims to solve]

[0005] In recent years, with the increasing demand for higher performance in electronic components and electrical equipment, photosensitive resin compositions are required to have high resolution, enabling the formation of finer resin patterns.

[0006] This disclosure has been made in view of the above circumstances and aims to provide a photosensitive resin composition that can form resin patterns with high resolution, and a method for manufacturing a circuit board using the same. [Means for solving the problem]

[0007] To achieve the above objective, this disclosure provides the following photosensitive resin composition and a method for manufacturing a circuit board using the same. [1] A photosensitive resin composition comprising (A) a resin having a phenolic hydroxyl group, (B) a compound having a methylol group or an alkoxyalkyl group, and (C) a photoacid generator, wherein (A) is a resin having structural units derived from hydroxystyrene. [2] The photosensitive resin composition according to [1], wherein the content of structural units derived from hydroxystyrene in the resin having structural units derived from hydroxystyrene is 80 mol% or more based on the total amount of structural units constituting the resin. [3] The photosensitive resin composition according to [1] or [2] above, wherein the resin having structural units derived from hydroxystyrene further has structural units derived from styrene. [4] A method for manufacturing a circuit board, comprising: (a) applying a photosensitive resin composition described in any of [1] to [3] above onto a substrate and drying the photosensitive resin composition to form a photosensitive layer; (b) exposing the photosensitive layer in a predetermined pattern, developing it, and further heating it to obtain a resin pattern; (c) plating the exposed portion of the substrate and the exposed portion of the resin pattern to form a conductive layer; and (d) removing a portion of the conductive layer to form a conductive pattern. [Effects of the Invention]

[0008] According to this disclosure, a photosensitive resin composition capable of forming resin patterns with high resolution, and a method for manufacturing a circuit board using the same can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view showing a method for manufacturing a circuit board according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] The following describes one embodiment of this disclosure in detail, but this disclosure is not limited thereto. In the following embodiment, the components (including elemental steps, etc.) are not necessarily essential unless specifically indicated or considered to be clearly essential in principle. The same applies to numerical values ​​and ranges, and should be interpreted as not unduly limiting this disclosure.

[0011] In this specification, the terms "layer" and "film" include not only structures that are formed over the entire surface when observed in a plan view, but also structures that are formed in part. The term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. "EO modified" means a compound having a (poly)oxyethylene group, and "PO modified" means a compound having a (poly)oxypropylene group. Here, "(poly)oxyethylene group" means at least one of an oxyethylene group and a polyoxyethylene group in which two or more ethylene groups are linked by an ether bond. "(poly)oxypropylene group" means at least one of an oxypropylene group and a polyoxypropylene group in which two or more propylene groups are linked by an ether bond. Numerical ranges indicated using "~" indicate a range that includes the numbers written before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described stepwise in this specification, the upper or lower limit of one step in the numerical range may be replaced with the upper or lower limit of another step in the numerical range. Also, in the numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. "A or B" means that either A or B is included, or both are included. Unless otherwise specified, the materials exemplified below can be used individually or as a mixture of two or more. The content of each component in the composition means the total amount of multiple substances present in the composition if there are multiple substances corresponding to each component, unless otherwise specified. In this specification, "solids" refers to the non-volatile content of the photosensitive resin composition excluding volatile substances (water, solvents, etc.), and includes components that are liquid, syrup-like, or waxy at room temperature (around 25°C).

[0012] [Photosensitive resin composition] The photosensitive resin composition of this embodiment contains (A) a resin having a phenolic hydroxyl group, (B) a compound having a methylol group or an alkoxyalkyl group, and (C) a photoacid generator. In the photosensitive resin composition of this embodiment, component (A) includes a resin having structural units derived from hydroxystyrene. According to the photosensitive resin composition of this embodiment, by containing the above components (A) to (C), and by including a resin in component (A) that has structural units derived from hydroxystyrene, a resin pattern can be formed with high resolution. The inventors speculate that the reason for obtaining this effect is as follows: That is, the structure derived from hydroxystyrene has excellent solubility in alkaline developer, but after reacting with component (B), its solubility in alkaline developer decreases drastically, resulting in a high contrast between the exposed and unexposed areas, which is thought to contribute to high resolution.

[0013] The photosensitive resin composition of this embodiment may further contain component (D): a basic compound. The photosensitive resin composition of this embodiment may further contain component (E): a silane coupling agent. The photosensitive resin composition of this embodiment may further contain component (F): a silicone compound. The photosensitive resin composition of this embodiment may further contain component (G): a solvent. Each component will be described below.

[0014] <(A) component> The resin having phenolic hydroxyl groups, which is component (A), is not particularly limited, but it is preferably a resin that is soluble in an alkaline aqueous solution. Component (A) includes a resin having structural units derived from hydroxystyrene, from the viewpoint of improving resolution. Examples of hydroxystyrene include o-hydroxystyrene, m-hydroxystyrene, and p-hydroxystyrene, but p-hydroxystyrene is preferred from the viewpoint of further improving resolution.

[0015] In a resin having a structural unit derived from hydroxystyrene, the content of the structural unit derived from hydroxystyrene may be 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, or 85 mol% or more based on the total amount of the structural units constituting the resin. When the content of the structural unit derived from hydroxystyrene is not less than the above lower limit value, the resolution and developability (solubility in an alkaline developer) tend to be further improved. The content of the structural unit derived from hydroxystyrene may be 100 mol% based on the total amount of the structural units constituting the resin having the structural unit derived from hydroxystyrene, or may be 95 mol% or less, or 90 mol% or less.

[0016] The resin having a structural unit derived from hydroxystyrene may be a resin (copolymer) having a structural unit derived from hydroxystyrene and a structural unit derived from styrene. By further having a structural unit derived from styrene, the solubility in an alkaline developer can tend to be appropriately controlled. In a resin having a structural unit derived from hydroxystyrene and a structural unit derived from styrene, the content of the structural unit derived from styrene may be 5 mol% or more, or 10 mol% or more based on the total amount of the structural units constituting the resin, and may be 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, or 15 mol% or less. When the content of the structural unit derived from styrene is not less than the above lower limit value, it is possible to prevent the solubility in an alkaline developer from becoming too high and causing variations in resolution. When the content of the structural unit derived from styrene is not more than the above upper limit value, the development time does not tend to become extremely long.

[0017] The resin having a structural unit derived from hydroxystyrene may or may not have other structural units other than those described above. Examples of other structural units include structural units derived from p-methylstyrene, p-ethylstyrene, p-propylstyrene, p-butylstyrene, p-methoxystyrene, and the like. In the resin having a structural unit derived from hydroxystyrene, the content of other structural units (structural units other than the structural unit derived from hydroxystyrene and the structural unit derived from styrene) may be 5 mol% or less, or 1 mol% or less based on the total amount of structural units constituting the resin.

[0018] (A) component may contain a novolak resin. Such a novolak resin can be obtained by condensing phenols and aldehydes in the presence of a catalyst.

[0019] Examples of the above phenols include phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-butylphenol, m-butylphenol, p-butylphenol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, catechol, resorcinol, pyrogallol, α-naphthol, β-naphthol, and the like.

[0020] Examples of the above aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, and the like.

[0021] Specific examples of such novolak resins include phenol / formaldehyde condensation novolak resins, cresol / formaldehyde condensation novolak resins, phenol-naphthol / formaldehyde condensation novolak resins, and the like.

[0022] In addition, other components (A) besides novolac resin include, for example, phenol-xylylene glycol condensation resin, cresol-xylylene glycol condensation resin, and phenol-dicyclopentadiene condensation resin. Component (A) can be used alone or as a mixture of two or more.

[0023] (A) Component (A) preferably has a weight-average molecular weight of 100,000 or less, more preferably 1,000 to 80,000, even more preferably 2,000 to 50,000, and particularly preferably 2,000 to 20,000, from the viewpoint of further improving the resolution, developability, thermal shock resistance, heat resistance, etc. of the resulting cured film. Here, the weight-average molecular weight is the value obtained by measuring by gel permeation chromatography (GPC) and converting it from the standard polystyrene calibration curve.

[0024] In the photosensitive resin composition of this embodiment, the content of component (A) is preferably 30 to 90% by mass, and more preferably 40 to 80% by mass, based on the total solid content of the photosensitive resin composition (total amount of components excluding the solvent). When the content of component (A) is within this range, the film formed using the resulting photosensitive resin composition tends to have even better developability with an alkaline aqueous solution.

[0025] In the photosensitive resin composition of this embodiment, the content of the resin having structural units derived from hydroxystyrene is preferably 30 to 90% by mass, and more preferably 40 to 80% by mass, based on the total solid content of the photosensitive resin composition (total amount of components excluding the solvent). When the content of the resin having structural units derived from hydroxystyrene is within this range, the film formed using the resulting photosensitive resin composition tends to have even better developability with an alkaline aqueous solution, and its resolution can be further improved.

[0026] From the viewpoint of further improving resolution, the content of resin having structural units derived from hydroxystyrene in component (A) is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on the total amount of component (A). Alternatively, the content of resin having structural units derived from hydroxystyrene in component (A) may be 100% by mass, based on the total amount of component (A).

[0027] <(B) component> The photosensitive resin composition of this embodiment contains a compound having a methylol group or an alkoxyalkyl group as component (B). Component (B) is preferably a compound further having at least one selected from the group consisting of aromatic rings, heterocyclic rings, and alicyclic rings. Here, an aromatic ring means an aromatic hydrocarbon group (for example, a hydrocarbon group having 6 to 10 carbon atoms), such as a benzene ring and a naphthalene ring. A heterocyclic ring means a cyclic group having at least one heteroatom such as a nitrogen atom, oxygen atom, or sulfur atom (for example, a cyclic group having 3 to 10 carbon atoms), such as a pyridine ring, imidazole ring, pyrrolidinone ring, oxazolidinone ring, imidazolidinone ring, and pyrimidinone ring. An alicyclic ring means a cyclic hydrocarbon group that does not have aromaticity (for example, a cyclic hydrocarbon group having 3 to 10 carbon atoms), such as a cyclopropane ring, cyclobutane ring, cyclopentane ring, and cyclohexane ring. An alkoxyalkyl group means a group in which an alkyl group is bonded to an alkyl group via an oxygen atom. Furthermore, the two alkyl groups may be different from each other, for example, alkyl groups having 1 to 10 carbon atoms. In addition, as component (B), compounds further having a phenolic hydroxyl group or compounds further having a hydroxymethylamino group can be used as preferred, but the compounds specified as component (A) are not included. Component (B) can be used alone or as a mixture of two or more.

[0028] As described later, by including component (C) in the photosensitive resin composition, acid is generated upon irradiation with active light or the like. By heating under this acid catalyst (PEB), a crosslinking reaction occurs between component (B) and component (A), or between components (B) themselves, accompanied by a de-alcoholization reaction, and a negative pattern can be formed.

[0029] The compound further having the phenolic hydroxyl group, by further having a phenolic hydroxyl group in addition to a methylol group or alkoxyalkyl group, can not only react with component (A) but also increase the dissolution rate of unexposed areas when developing with an alkaline aqueous solution, thereby improving sensitivity. The molecular weight of the compound having the phenolic hydroxyl group is preferably 100 to 1,500, more preferably 150 to 1,000, and even more preferably 180 to 800, taking into consideration the need to improve solubility in alkaline aqueous solutions, photosensitivity, mechanical properties, etc., in a well-balanced manner.

[0030] As the compound further having the phenolic hydroxyl group described above, conventionally known compounds can be used, but the compound represented by the following general formula (1) is preferred because it has an excellent balance between the effect of promoting the dissolution of unexposed areas and the effect of preventing melting during the curing of the photosensitive resin film.

[0031] [ka] In general formula (1), Z represents a 1- to 4-valent organic group, and R 24 R represents a hydrogen atom or a monovalent organic group. 25 Here, examples of monovalent organic groups include alkyl groups with 1 to 10 carbon atoms, such as methyl, ethyl, and propyl groups; alkenyl groups with 2 to 10 carbon atoms, such as vinyl groups; aryl groups with 6 to 30 carbon atoms, such as phenyl groups; and groups in which some or all of the hydrogen atoms of these hydrocarbon groups are replaced with halogen atoms such as fluorine atoms. 24 ~R 25If there are multiple items, they may be identical or different from one another.

[0032] The compound represented by general formula (1) is preferably the compound represented by general formula (2).

[0033] [ka] In general formula (2), X 1 R represents a single bond or a divalent organic group, and each of the R groups independently represents an alkyl group (for example, an alkyl group with 1 to 10 carbon atoms).

[0034] Furthermore, as the compound having the phenolic hydroxyl group described above, a compound represented by general formula (3) may be used.

[0035] [ka] In general formula (3), each of the R's independently represents an alkyl group (for example, an alkyl group having 1 to 10 carbon atoms).

[0036] Furthermore, compounds in which Z is a single bond in general formula (1) are biphenol (dihydroxybiphenyl) derivatives. Examples of divalent organic groups represented by Z include alkylene groups with 1 to 10 carbon atoms, such as methylene, ethylene, and propylene groups; alkylidene groups with 2 to 10 carbon atoms, such as ethylidene groups; arylene groups with 6 to 30 carbon atoms, such as phenylene groups; groups in which some or all of the hydrogen atoms of these hydrocarbon groups are replaced with halogen atoms such as fluorine atoms; sulfonyl groups; carbonyl groups; ether bonds; sulfide bonds; and amide bonds. Among these, Z is preferably a divalent organic group represented by the following general formula (4).

[0037] [ka] In general formula (4), X 2represents a single bond, an alkylene group (e.g., an alkylene group having 1 to 10 carbon atoms), an alkylidene group (e.g., an alkylidene group having 2 to 10 carbon atoms), a group in which some or all of the hydrogen atoms thereof are substituted with halogen atoms, a sulfonyl group, a carbonyl group, an ether bond, a sulfide bond or an amide bond. R 28 represents a hydrogen atom, a hydroxyl group, an alkyl group (e.g., an alkyl group having 1 to 10 carbon atoms) or a haloalkyl group, and e represents an integer of 1 to 10. A plurality of R 28 and X 2 may be the same as or different from each other. Here, the haloalkyl group means an alkyl group substituted with a halogen atom.

[0038] Examples of the compound further having the above hydroxymethylamino group include (poly)(N-hydroxymethyl)melamine, (poly)(N-hydroxymethyl) glycoluril, (poly)(N-hydroxymethyl) benzoguanamine, (poly)(N-hydroxymethyl) urea, etc. Further, a nitrogen-containing compound in which all or part of the hydroxymethylamino groups of these compounds are alkyl etherified may be used. Here, examples of the alkyl group of the alkyl ether include a methyl group, an ethyl group, a butyl group or a mixture thereof, and it may contain an oligomer component formed by partial self-condensation. Specifically, hexakis(methoxymethyl)melamine, hexakis(butoxymethyl)melamine, tetrakis(methoxymethyl) glycoluril, tetrakis(butoxymethyl) glycoluril, tetrakis(methoxymethyl) urea, etc. may be mentioned.

[0039] Specifically, the compound having the above hydroxymethylamino group is preferably a compound represented by the general formula (5) or a compound represented by the general formula (6).

[0040]

Chemical formula

[0041] The content of component (B) is preferably 10 to 50 parts by mass, more preferably 15 to 45 parts by mass, and particularly preferably 15 to 40 parts by mass, per 100 parts by mass of component (A). When the content of component (B) is 10 parts by mass or more, the reaction of the exposed area is sufficient, so the resolution does not tend to decrease, and chemical resistance and heat resistance tend to be good. When the content is 50 parts by mass or less, it becomes easier to form the photosensitive resin composition on the desired support, and the resolution tends to be good.

[0042] <(C) component> The photoacid generator, which is component (C), is a compound that generates acid upon irradiation with active light or the like. Here, the molar extinction coefficient of component (C) in the h-line or i-line (a coefficient obtained by converting the absorbance of a specific sample to a cell with an analyte concentration of 1 mol / L and a path length of 1 cm) is preferably 100 or more from the viewpoint of improving sensitivity, resolution, pattern formation, etc. in processing using an active light irradiation direct writing exposure apparatus for the h-line or i-line.

[0043] Component (C) may be a nonionic photoacid generator or an ionic photoacid generator. From the viewpoint of resolution, component (C) is preferably bulky with a molecular weight of 150 or more. Furthermore, from the viewpoint of complying with environmental regulations, component (C) is preferably fluorine-free.

[0044] (C) Examples of components include "NA-CS1" manufactured by Sunapro Co., Ltd., and "Irgacure PAG121" and "Irgacure PAG103" manufactured by BASF Japan Ltd.

[0045] Furthermore, as component (C), examples include triarylsulfonium salts having at least one cation selected from the group consisting of compounds represented by the following formula (c1), compounds represented by the following formula (c2), compounds represented by the following formula (c3), and compounds represented by the following formula (c4).

[0046] [ka]

[0047] [ka]

[0048] [ka]

[0049] [ka]

[0050] The hydrogen atoms of the phenyl groups in formulas (c1), (c2), (c3), and (c4) may be substituted with at least one selected from the group consisting of a hydroxyl group, a C1-C12 alkyl group, a C1-C12 alkoxy group, a C2-C12 alkylcarbonyl group, and a C2-C12 alkoxycarbonyl group. If there are multiple substituents, they may be the same or different from each other.

[0051] The above-mentioned component (C) can be used individually or as a mixture of two or more.

[0052] Component (C) may be a compound that generates acid upon irradiation with h-ray or i-ray active light. Examples of such compounds include onium salt compounds, halogen-containing compounds, diazoketone compounds, sulfone compounds, sulfonic acid compounds, sulfonimide compounds, and diazomethane compounds. In particular, from the viewpoint of ease of availability, the other photoacid generator may be at least one selected from the group consisting of onium salt compounds and sulfonimide compounds. Especially when using a solvent, the other photoacid generator may be an onium salt compound from the viewpoint of excellent solubility in the solvent. Specific examples are shown below.

[0053] Examples of onium salt compounds include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, and pyridinium salts. Specific examples of onium salt compounds include diaryliodonium salts such as diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluorobutanesulfonate, diphenyliodonium heptadecafluorooctanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluorophosphate, diphenyliodonium tris(pentafluoroethyl)trifluorophosphate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis(pentafluorophenyl)borate, and diphenyliodonium tris[(trifluoromethyl)sulfonyl]methanide; as well as triarylsulfonium salts. In particular, from the viewpoint of further improving sensitivity and thermal stability, sulfonium salts may be used, and from the viewpoint of excellent sensitivity in the h-ray region and further improving thermal stability, triarylsulfonium salts may be used. Furthermore, onium salt compounds may be onium borate salts or onium gallate salts. Onium salt compounds can be used individually or in combination of two or more.

[0054] Examples of triarylsulfonium salts include sulfonium salts having at least one cation selected from the group consisting of the compound represented by formula (c1), the compound represented by formula (c2), the compound represented by formula (c3), and the compound represented by formula (c4), and an anion having at least one skeleton selected from the group consisting of a tetraphenylborate skeleton, a tetraphenylgallate skeleton, a C1-C20 alkylsulfonate skeleton, a phenylsulfonate skeleton, a C1-C20 trisalkylsulfonylmethanide skeleton, a tetrafluoroborate skeleton, a tetrafluorogallate skeleton, a hexafluoroantimonate skeleton, and a hexafluorophosphate skeleton.

[0055] Furthermore, the hydrogen atoms of the phenyl groups in the tetraphenylborate skeleton and tetraphenylgallate skeleton may be substituted with at least one selected from the group consisting of fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, hydroxyl groups, C1-C12 alkyl groups, C1-C12 alkoxy groups, C2-C12 alkylcarbonyl groups, and C2-C12 alkoxycarbonyl groups. If there are multiple substituents, they may be the same or different from each other.

[0056] The hydrogen atoms of the alkyl sulfonate skeleton may be substituted with at least one selected from the group consisting of fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, hydroxyl groups, alkoxy groups, alkylcarbonyl groups, and alkoxycarbonyl groups. If there are multiple substituents, they may be the same or different from each other.

[0057] The hydrogen atoms of the phenyl group in the above phenylsulfonate skeleton may be substituted with at least one selected from the group consisting of fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, hydroxyl groups, C1-C12 alkyl groups, C1-C12 alkoxy groups, C2-C12 alkylcarbonyl groups, and C2-C12 alkoxycarbonyl groups. If there are multiple substituents, they may be the same or different from each other.

[0058] The hydrogen atoms of the above trisalkylsulfonyl methanide skeleton may be substituted with at least one selected from the group consisting of fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, hydroxyl groups, alkoxy groups, alkylcarbonyl groups, and alkoxycarbonyl groups. If there are multiple substituents, they may be the same or different from each other.

[0059] The fluorine atom of the hexafluorophosphate skeleton described above may be substituted with at least one selected from the group consisting of a hydrogen atom, a C1-C12 alkyl group, and a C1-C12 perfluoroalkyl group. If there are multiple substituents, they may be the same or different from each other.

[0060] (C) The sulfonium salt used as component may be a compound having at least one selected from the group consisting of [4-(4-biphenylylthio)phenyl]-4-biphenylylphenylsulfonium, (2-methyl)phenyl[4-(4-biphenylylthio)phenyl]4-biphenylylsulfonium, [4-(4-biphenylylthio)-3-methylphenyl]4-biphenylylphenylsulfonium, (2-ethoxy)phenyl[4-(4-biphenylylthio)-3-ethoxyphenyl]4-biphenylylsulfonium, and tris[4-(4-acetylphenylsulfanyl)phenyl]sulfonium as a cation, from the viewpoint of further superior sensitivity, resolution, and insulating properties.

[0061] The anion of the sulfonium salt used as component (C) may be a compound having at least one selected from the group consisting of trifluoromethanesulfonate, nonafluorobutanesulfonate, hexafluoroantimonate, tris[(trifluoromethyl)sulfonyl]methanide, 10-camphorsulfonate, tris(pentafluoroethyl)trifluorophosphate, tetrakis(pentafluorophenyl)borate, and tetrakis(pentafluorophenyl)gallate.

[0062] Specific examples of sulfonium salts include (2-ethoxy)phenyl[4-(4-biphenylylthio)-3-ethoxyphenyl]4-biphenylylsulfonium nonafluorobutanesulfonate, [4-(4-biphenylylthio)phenyl]-4-biphenylylphenylsulfonium tetrakis(pentafluorophenyl)borate, [4-(4-biphenylylthio)phenyl]-4-biphenylylphenylsulfonium tetrakis(pentafluorophenyl)gallate, tris[4-(4-acetylphenylsulfanyl)phenyl]sulfonium tetrakis(pentafluorophenyl)borate, and tris[4-(4-acetylphenylsulfanyl)phenyl]sulfonium tetrakis(pentafluorophenyl)gallate. Sulfonium salts can be used individually or in combination of two or more types.

[0063] Similar to the triarylsulfonium salt compounds mentioned above, sulfonimide compounds used as photoacid generators with excellent sensitivity in the h-ray region include, for example, N-(trifluoromethylsulfonyloxy)succinimide, N-(trifluoromethylsulfonyloxy)phthalimide, N-(trifluoromethylsulfonyloxy)diphenylmaleimide, N-(trifluoromethylsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-(trifluoromethylsulfonyloxy)naphthylimide, N-(p-toluenesulfonyloxy)-1,8-naphthalimide, and N-(10-camphorsulfonyloxy)-1,8-naphthalimide. Sulfonimide compounds can be used individually or in combination of two or more.

[0064] (C) Each of the compounds exemplified above as component (C) can be used individually or in combination of two or more.

[0065] Component (C) may be substantially fluorine-free. The fluorine content in component (C) may be 100 ppm by mass or less.

[0066] The content of component (C) may be 1 to 15 parts by mass per 100 parts by mass of component (A), and may also be 1 to 10 parts by mass, 2 to 10 parts by mass, 3 to 8 parts by mass, or 4 to 6 parts by mass, from the viewpoint of further improving the sensitivity, resolution, rectangularity, etc. of the photosensitive resin composition of this embodiment.

[0067] <(D) component> The photosensitive resin composition of this embodiment may contain a basic compound (quencher) as component (D). Using component (D) tends to result in good resolution.

[0068] (D) Components include amine compounds such as trimethylamine, diethylamine, triethylamine, di-n-propylamine, tri-n-propylamine, tri-n-pentylamine, tribenzylamine, diethanolamine, triethanolamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and ethylenediamine; amide compounds such as formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, and benzamide; lactams such as pyrrolidone and N-methylpyrrolidone; methylurea, 1,1-dimethylurea, 1 Examples include urea compounds such as ,3-dimethylurea, 1,1,3,3-tetramethylurea, and 1,3-diphenylurea; nitrogen-containing heterocyclic compounds such as imidazole, benzimidazole, 4-methylimidazole, 1,2,4-triazole, 1,2,3-benzotriazole, 5-benzyl-1H-tetrazole, 5-amino-1H-tetrazole, 8-oxyquinoline, acridine, purine, pyrrolidine, piperidine, 2,4,6-tri(2-pyridyl)-S-triazine, piperazine, 1,4-dimethylpiperazine, 1,4-diazabicyclo[2.2.2]octane, and pyridine; and morpholine compounds such as morpholine and 4-methylmorpholine.

[0069] The content of component (D) is preferably 0.01 to 1.0% by mass, more preferably 0.02 to 0.8% by mass, and even more preferably 0.03 to 0.6% by mass, based on the total solid content of the photosensitive resin composition. When the content of component (D) is above the lower limit, good resolution tends to be obtained, and when it is below the upper limit, pattern formation tends to be possible without requiring a high exposure amount (no significant decrease in sensitivity occurs). Component (D) is non-volatile, even if it is liquid at room temperature, and therefore corresponds to "solid content" in this specification.

[0070] <(E) component> The photosensitive resin composition of this embodiment may contain a silane coupling agent as component (E). By including component (E), the adhesion strength between the photosensitive layer and the substrate after resin pattern formation can be improved. Component (E) may be a silane coupling agent having an acid anhydride group. By using a silane coupling agent having an acid anhydride group, the adhesion reliability of the resulting cured film to the inorganic substrate can be improved. Component (E) can be used alone or as a mixture of two or more types.

[0071] Examples of component (E) include alkylsilanes, alkoxysilanes, vinylsilanes, epoxysilanes, aminosilanes, acryloylsilanes, methacryloylsilanes, mercaptosilanes, sulfidosilanes, isocyanatesilanes, sulfursilanes, styrylsilanes, alkylchlorosilanes, and the like.

[0072] The content of component (E) is preferably 0.5 to 10% by mass, more preferably 1 to 8% by mass, and even more preferably 1.5 to 5% by mass, based on the total solid content of the photosensitive resin composition. When the content of component (E) is 0.5% by mass or more, the reliability of adhesion of the cured film to the substrate can be further improved. When the content of component (E) is 10% by mass or less, the increase in viscosity of the photosensitive resin composition during long-term storage can be suppressed.

[0073] <(F) component> The photosensitive resin composition of this embodiment may contain a silicone compound as component (F). The silicone compound, which is component (F), is a leveling agent capable of imparting smoothness to the surface of the coating film. This silicone compound orients itself to the surface of the coating film after application, thereby ensuring surface smoothness or improving wettability to the substrate surface. These functions are achieved by orienting themselves in the photosensitive resin composition and reducing surface tension.

[0074] Component (F) is not particularly limited as long as it is a silicone compound, but in terms of leveling effect, it is especially preferable to use a compound having a polysiloxane structure. Furthermore, as a silicone compound, a modified silicone compound having an organic group that is easily compatible with the other organic components that constitute the coating film is more preferable from the viewpoint of compatibility with the other organic components mentioned above. Specific examples are shown below.

[0075] Component (F) includes polyether-modified polymethylsiloxane, polyether-modified polydimethylsiloxane, polyether-modified polymethylalkylsiloxane, polyether-modified polymethyldialkylsiloxane, aralkyl-modified polymethylsiloxane, aralkyl-modified polymethyldisiloxane, aralkyl-modified polymethylalkylsiloxane, aralkyl-modified polymethylalkyldisiloxane, phenyl-modified polymethylsiloxane, phenyl-modified polymethyldisiloxane, phenyl-modified polymethylalkylsiloxane, phenyl-modified polymethylalkyldisiloxane, acrylate or methacrylate-modified polymethylsiloxane, acrylate or methacrylate-modified polymethylalkyldisiloxane, and the like.

[0076] From the viewpoint of improving the surface smoothness, sensitivity, resolution, pattern shape, etc. of the coating film of the photosensitive resin composition of this embodiment, the content of component (F) is preferably 0.01 to 1.0 parts by mass, and more preferably 0.03 to 0.5 parts by mass, per 100 parts by mass of the total solid content excluding component (F) in the photosensitive resin composition.

[0077] <(G) component> The photosensitive resin composition of this embodiment may contain a solvent as component (G).

[0078] Component (G) may contain at least one solvent selected from the group consisting of ethylene glycol monoalkyl ether acetate, propylene glycol monoalkyl ether acetate, lactic acid ester, and γ-butyrolactone. By using these solvents, devices with good resolution and high reliability can be manufactured even when the coating film thickness is thin, under high humidity conditions. The reason for this is not entirely clear, but it is thought that some of the reasons include the fact that these solvents have an extremely small effect on components (A) to (F), and that they have a certain boiling point, which prevents a decrease in coating film strength due to solvent volatilization during coating film formation.

[0079] Examples of alkyl groups in ethylene glycol monoalkyl ether acetate and propylene glycol monoalkyl ether acetate include methyl, ethyl, n-propyl, and isopropyl groups, with methyl, ethyl, or n-propyl groups being preferred, and methyl or ethyl groups being more preferred.

[0080] Examples of lactate esters include methyl lactate, ethyl lactate, n-propyl lactate, and isopropyl lactate, but methyl lactate or ethyl lactate is preferred, and ethyl lactate is more preferred.

[0081] Component (G) preferably contains ethylene glycol monoalkyl ether acetate, propylene glycol monoalkyl ether acetate, or lactate ester, more preferably propylene glycol monoalkyl ether acetate or lactate ester, and even more preferably propylene glycol monomethyl ether acetate or ethyl lactate, from the viewpoint of improving the insulation reliability of the formed resin pattern.

[0082] Component (G) may contain other solvents other than at least one solvent selected from the group consisting of ethylene glycol monoalkyl ether acetate, propylene glycol monoalkyl ether acetate, lactic acid ester, and γ-butyrolactone as described above. Examples of other solvents include propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether; propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, and propylene glycol dibutyl ether; cellosolves such as ethyl cellosolve and butyl cellosolve; and ethyl carbitol such as butyl carbitol. Examples include aliphatic carboxylic acid esters such as n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, isopropyl propionate, n-butyl propionate, and isobutyl propionate; other esters such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl pyruvate, and ethyl pyruvate; aromatic hydrocarbons such as toluene and xylene; and ketones such as 2-butanone, 2-heptanone, 3-heptanone, 4-heptanone, and cyclohexanone. The content of these other solvents is preferably 50% by mass or less of the total solvent, more preferably 25% by mass or less, and even more preferably substantially absent (e.g., 2% by mass or less).

[0083] The content of component (G) is preferably 30 to 220 parts by mass, and more preferably 60 to 200 parts by mass, based on 100 parts by mass of the total amount of the photosensitive resin composition excluding component (G).

[0084] <Other ingredients> The photosensitive resin composition of this embodiment may contain other components besides those described above. Examples of other components include colorants, adhesion aids, leveling agents other than the silicone compounds described above, inorganic fillers, and inhibitors of reactions associated with irradiation with active light.

[0085] [Photosensitive element] The photosensitive resin composition of this embodiment may be used in the form of a photosensitive element. The photosensitive element comprises a support and a photosensitive layer provided on the support, wherein the photosensitive layer contains the above-described photosensitive resin composition. The photosensitive layer can be formed from the above-described photosensitive resin composition. The photosensitive element of this embodiment may further include a protective film covering the photosensitive layer on the photosensitive layer.

[0086] As the support, for example, a polymer film having heat resistance and solvent resistance, such as polyester (e.g., polyethylene terephthalate), polypropylene, or polyethylene, can be used. The thickness of the support (polymer film) may be 5 to 50 μm. Alternatively, the polymer film may be used by laminating one film on the support and the other as a protective film on both sides of the photosensitive layer.

[0087] As the protective film mentioned above, for example, a polymer film having heat resistance and solvent resistance, such as polyester (e.g., polyethylene terephthalate), polypropylene, or polyethylene, can be used.

[0088] The above-mentioned photosensitive layer can be formed by applying the above-mentioned photosensitive resin composition onto a support or protective film and drying it. Application methods include dipping, spraying, bar coating, roll coating, and spin coating. The thickness of the photosensitive layer varies depending on the application, but after drying, it is preferably 1 to 50 μm, more preferably 2 to 40 μm, and even more preferably 3 to 30 μm.

[0089] The range of solid content of each component (components (A) to (F) and other components) in the photosensitive layer, excluding volatile components, may be the same as the range of solid content of each component in the photosensitive resin composition.

[0090] [Manufacturing method for circuit boards] Figure 1 shows a method for manufacturing a circuit board according to one embodiment of the present disclosure. The method for manufacturing a circuit board according to this embodiment comprises: (a) applying the above-mentioned photosensitive resin composition onto a substrate 1 and drying the photosensitive resin composition to form a photosensitive layer 2; (b) exposing the photosensitive layer 2 in a predetermined pattern, developing it, and further heating it to form a resin pattern 4; (c) plating the exposed parts of the substrate 1 and the exposed parts of the resin pattern 4 to form a conductor layer 7; and (d) removing a part of the conductor layer 7 to form a conductor pattern 8 (circuit). In other words, the method for manufacturing a circuit board according to this embodiment is a method for manufacturing a circuit board having a resin pattern 4 formed using a predetermined pattern and a miniaturized conductor pattern 8 on a substrate 1. Here, the resin pattern is a resin pattern obtained by curing a photosensitive layer on which a predetermined pattern has been formed, and part or all of the resin in the resin pattern is cured. In other words, the resin pattern means a cured film. Each step will be described in detail below.

[0091] <(a) Process> Step (a) is a step of applying the above-mentioned photosensitive resin composition onto the substrate 1 and drying the photosensitive resin composition to form a photosensitive layer 2 (see Figure 1(a)). In other words, step (a) can also be described as a step of obtaining a substrate having a photosensitive layer 2 containing the photosensitive resin composition.

[0092] Methods for applying the photosensitive resin composition to a substrate include, for example, dipping, spraying, bar coating, roll coating, and spin coating. The thickness of the coating film can be appropriately controlled by adjusting the coating means, the solid content concentration, and the viscosity of the photosensitive resin composition. The thickness of the photosensitive layer 2 varies depending on the application, but it is preferable that the thickness of the photosensitive layer 2 after drying be 1 to 20 μm, and more preferably 2 to 10 μm.

[0093] As substrate 1, for example, inorganic substrates such as SiO2 wafers, glass substrates, SiN wafers, silicon wafers, and alumina substrates can be used. Other substrates besides inorganic substrates may also be used as substrate 1. Substrate 1 may also be resin-coated copper foil, copper-clad laminates, etc. Furthermore, substrate 1 may be a silicon wafer with a metal sputtered film attached, or an inorganic substrate with a cured resin layer formed using a photosensitive resin composition.

[0094] <(b) Process> (b) Step (b) involves exposing the photosensitive layer 2 in a predetermined pattern, performing a heat treatment (PEB: post-exposure bake), developing it, and then performing another heat treatment to obtain a resin pattern 4 (see Figures 1(b) and (c)).

[0095] First, the photosensitive layer 2 is exposed in a predetermined pattern via a predetermined mask pattern. Examples of active light sources used for exposure include light from a g-line stepper; ultraviolet light from low-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, i-line steppers, etc.; electron beams; and laser light. The exposure amount is appropriately selected depending on the light source used, the thickness of the coating film, etc., but for example, when irradiating a coating film with a thickness of 1 to 20 μm with ultraviolet light using a high-pressure mercury lamp, the exposure amount is 10 to 3000 mJ / cm². 2 It can be to a certain extent.

[0096] Next, the photosensitive layer 2 after exposure is subjected to heat treatment (PEB). Heat treatment (PEB) can be performed, for example, on a hot plate at 100-140°C for 30 seconds to 3 minutes.

[0097] Next, the photosensitive layer 2 after heat treatment (PEB) is developed with an alkaline developer to dissolve and remove the areas other than those hardened by exposure and heat treatment (PEB) (unexposed areas), thereby obtaining a photosensitive layer 2 with a predetermined pattern (see Figure 1(b)). The areas removed here become the areas (circuit grooves 3) where the conductive pattern 8 should be formed. In this case, development methods include shower development, spray development, immersion development, and paddle development. Development conditions are usually 20 to 40°C for 20 seconds to 5 minutes.

[0098] As the alkaline developer, for example, an alkaline aqueous solution prepared by dissolving an alkaline compound such as sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, or choline in water to a concentration of about 1 to 10% by mass, or an alkaline aqueous solution such as ammonia water can be used. Among these, tetramethylammonium hydroxide aqueous solution is preferred because it has excellent resolution for the resin pattern 4. In addition, an appropriate amount of a water-soluble organic solvent such as methanol or ethanol, or a surfactant, can be added to the alkaline aqueous solution. After developing with the alkaline developer, wash with water and dry.

[0099] Next, a resin pattern 4 is obtained by heat-treating the photosensitive layer 2 on which a predetermined pattern has been formed (see Figure 1(c)). The heat treatment brings about insulating film properties. The conditions for the heat treatment are not particularly limited and can be adjusted according to the application of the cured product. For example, the conditions may be a heating temperature of 50 to 250°C and a heating time of 30 minutes to 10 hours.

[0100] Furthermore, the heat treatment may be carried out in two stages for purposes such as ensuring sufficient hardening and preventing deformation of the resulting resin pattern 4. When heat treatment is carried out in two stages, for example, the heating temperature and heating time for the first stage can be set to 50-120°C and 5 minutes-2 hours, respectively, and the heating temperature and heating time for the second stage can be set to 80-200°C and 10 minutes-10 hours, respectively.

[0101] When performing heat treatment under the above conditions, the heating equipment is not particularly limited; for example, a general oven or infrared furnace can be used.

[0102] <(c) Process> (c) Step (c) is a step in which the exposed parts of the substrate 1 and the exposed parts of the resin pattern 4 are plated to form the conductive layer 7 (see Figures 1(d) and (e)). The exposed parts of the substrate 1 refer to the areas on the surface of the substrate 1 where the resin pattern is formed but the resin pattern is not formed therein.

[0103] The plating method is not particularly limited, but may include, for example, electroplating, electroless plating, or sputtering.

[0104] The thickness of the conductor layer 7 can be appropriately adjusted by the height of the wiring groove to be formed, but it is preferably 1 to 35 μm, and more preferably 2 to 25 μm.

[0105] The conductive layer 7 may consist of a seed metal layer 5 and a plating layer 6 grown on it. That is, step (c) may include a step of forming the seed metal layer 5 on the exposed portion of the substrate 1 and the exposed portion of the resin pattern 4 (see Figure 1(d)). When forming the seed metal layer 5, the plating layer 6 can be formed by plating the formed seed metal layer 5 (see Figure 1(e)).

[0106] The method for forming the seed metal layer 5 is not particularly limited, but examples include electroless plating and sputtering.

[0107] When forming the seed metal layer 5 by electroless plating, the metal constituting the seed metal layer 5 may be a single metal such as gold, platinum, silver, copper, aluminum, cobalt, chromium, nickel, titanium, tungsten, iron, tin, or indium, or a solid solution (alloy) of two or more metals such as nickel-chromium alloy. Among these, from the viewpoint of versatility in metal film formation, cost, and ease of removal by etching, the metal constituting the seed metal layer 5 is preferably chromium, nickel, titanium, nickel-chromium alloy, aluminum, zinc, copper-nickel alloy, copper-titanium alloy, gold, silver, or copper, more preferably chromium, nickel, titanium, nickel-chromium alloy, aluminum, zinc, gold, silver, or copper, and particularly preferably titanium or copper. Furthermore, the seed metal layer 5 may be a single layer or a multi-layer structure in which two or more different metals are laminated.

[0108] When forming the seed metal layer 5 by electroless plating, an electroless plating solution is used. As the electroless plating solution, a known self-catalytic type electroless plating solution can be used, and the metal species, reducing agent species, complexing agent species, hydrogen ion concentration, dissolved oxygen concentration, etc. contained in the electroless plating solution are not particularly limited. Examples of electroless plating solutions that can be used include: an electroless copper plating solution using ammonium hypophosphate, hypophosphorous acid, ammonium borohydride, hydrazine, formalin, etc. as a reducing agent; an electroless nickel-phosphorus plating solution using sodium hypophosphate as a reducing agent; an electroless nickel-boron plating solution using dimethylaminoborane as a reducing agent; an electroless palladium plating solution; an electroless palladium-phosphorus plating solution using sodium hypophosphate as a reducing agent; an electroless gold plating solution; an electroless silver plating solution; and an electroless nickel-cobalt-phosphorus plating solution using sodium hypophosphate as a reducing agent.

[0109] Furthermore, the method for forming the seed metal layer 5 by electroless plating may be, for example, a method in which a catalyst nucleus such as silver, palladium, zinc, or cobalt is attached to the portion where the seed metal layer 5 will be formed, and then a thin metal film is formed on the catalyst nucleus using the electroless plating solution described above.

[0110] The method for attaching catalyst nuclei to the exposed portions of the substrate 1 and the exposed portions of the resin pattern 4 is not particularly limited. For example, a solution can be prepared by dissolving a metal compound, salt, or complex of the metal to be used as a catalyst nucleus in water or an organic solvent (e.g., alcohol and chloroform) to a concentration of 0.001 to 10% by mass. The substrate 1 on which the resin pattern 4 is formed is then immersed in this solution, and the metal in the solution is reduced to precipitate the metal. The solution in the above method may contain acids, alkalis, complexing agents, reducing agents, etc., as needed.

[0111] When forming the seed metal layer 5 by sputtering, the metal constituting the seed metal layer 5 can be the same as the metal used when forming the seed metal layer 5 by electroless plating.

[0112] The metal constituting the plating layer 6 is not particularly limited, but copper is preferred. A method for forming the plating layer 6 on the seed metal layer 5 includes, for example, growing the plating by wet plating such as electroplating.

[0113] The seed metal layer 5 can be treated with a rust inhibitor to prevent rust formation before the plating layer 6 is formed.

[0114] When forming the seed metal layer 5, there are no particular restrictions on the thickness of the seed metal layer 5, but it is preferably 10 nm to 5000 nm, more preferably 20 nm to 2000 nm, even more preferably 30 nm to 1000 nm, particularly preferably 50 nm to 500 nm, and most preferably 50 nm to 300 nm. When the thickness is 10 nm or more, the plating layer 6 tends to be formed uniformly by electroplating, and when the thickness is 5000 nm or less, the time required to remove the seed metal layer by etching or polishing can be appropriately shortened, thereby reducing the cost of removing the seed metal layer 5.

[0115] After the formation of the conductive layer 7, the conductive layer 7 may be heated to improve adhesion, etc. The heating temperature is usually 50 to 350°C, preferably 80 to 250°C. Heating may also be carried out under pressurized conditions. Examples of pressurized methods include using physical pressurizing means such as a hot press or a pressurized heating roll machine. The applied pressure is usually 0.1 to 20 MPa, preferably 0.5 to 10 MPa. Within this range, the adhesion between the seed metal layer 5 and the resin pattern 4 or substrate 1 tends to be excellent.

[0116] <(d) Process> Step (d) is a step in which a portion of the conductive layer 7 is removed to form the conductive pattern 8 (see Figure 1(f)). As shown in Figure 1(e), the conductive layer 7 is formed on the entire surface of the exposed portion of the substrate 1 and the exposed portion of the resin pattern 4. In other words, the plating (metal film) is formed in areas other than the area where the conductive pattern 8 is to be formed (circuit groove 3). Therefore, step (d) can be said to be a step in which the metal film formed in areas of the conductive layer 7 other than the circuit groove 3 is removed.

[0117] The method for removing a portion of the conductive layer 7 may be any known method for removing metal. For example, it may be a method by mechanical polishing and / or etching.

[0118] When removing a portion of the conductor layer 7 by mechanical polishing, the mechanical polishing method is preferably chemical mechanical polishing (hereinafter also referred to as "CMP"). A method for removing a portion of the conductor layer 7 by CMP may be, for example, a method in which a polishing cloth (polishing pad) is attached to a polishing platen, the surface of the polishing cloth is immersed in a metal polishing compound, the surface of the conductor layer 7 is pressed against the surface of the polishing cloth, a predetermined pressure (hereinafter referred to as "polishing pressure") is applied to the surface of the conductor layer 7 from the back side, and the polishing platen is rotated while this pressure is applied to the surface of the conductor layer 7, thereby removing a portion of the conductor layer 7 by mechanical friction between the polishing compound and the surface of the conductor layer 7.

[0119] The metal polishing compound used in CMP may contain, for example, an oxidizing agent and solid abrasive grains (hereinafter simply referred to as "abrasive grains"), and may further contain, if necessary, a metal oxide dissolving agent, a protective film forming agent, etc. The basic mechanism of CMP using an abrasive compound containing an oxidizing agent and abrasive grains is thought to be as follows: First, the surface of the metal film to be polished is oxidized by the oxidizing agent to form an oxide layer, and this oxide layer is then scraped off by the abrasive grains, thereby polishing the metal film. When polishing is performed by this mechanism, the oxide layer on the surface of the metal film formed in the circuit groove 3 does not come into contact with the polishing cloth very well, so the scraping effect of the abrasive grains does not extend much to the metal film formed in the circuit groove 3. Therefore, as polishing by CMP progresses, the metal film in areas other than the circuit groove 3 tends to be removed, and the polished surface tends to become flatter.

[0120] The abrasive is preferably one that can be used at a polishing speed in the range of 5000 to 3000 Å / min.

[0121] When removing a portion of the conductive layer 7 by etching, the etching method can be sandblasting or a wet etching process. In the sandblasting method, etching is performed by spraying cutting particles such as silica or alumina onto the portion of the conductive layer 7 to be removed. In the wet etching process, etching is performed using an etching solution. Examples of etching solutions that can be used include cupric chloride solution, ferric chloride solution, alkaline etching solution, ammonium persulfate aqueous solution, and hydrogen peroxide etching solution.

[0122] The thickness of the metal film in the portion of the conductive layer 7 that is removed in step (d), i.e., the region other than the circuit groove 3, may be approximately 0.1 to 35 μm.

[0123] The circuit board fabricated by the above method allows for the mounting of semiconductor elements in corresponding locations and ensures electrical connections. Furthermore, the above method makes it possible to obtain a circuit board having miniaturized conductor patterns 8. [Examples]

[0124] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited in any way by these examples.

[0125] [Examples 1-4 and Comparative Example 1] <Preparation of photosensitive resin composition> Each component shown in Table 1 was blended in the amounts (unit: parts by mass) shown in the same table to obtain the photosensitive resin compositions of Examples 1 to 4 and Comparative Example 1.

[0126] The abbreviations used in Table 1 are as follows: A-1: Copolymer consisting of 90 mol% structural units derived from p-hydroxystyrene and 10 mol% structural units derived from styrene (manufactured by Maruzen Petrochemical Co., Ltd., product name: Marcalinker CST90, weight-average molecular weight: 10500) A-2: Copolymer consisting of 85 mol% structural units derived from p-hydroxystyrene and 15 mol% structural units derived from styrene (manufactured by Maruzen Petrochemical Co., Ltd., product name: Marcalinker CST85, weight-average molecular weight: 10500) A-3: Copolymer consisting of 70 mol% structural units derived from p-hydroxystyrene and 30 mol% structural units derived from styrene (manufactured by Maruzen Petrochemical Co., Ltd., product name: Marcalinker CST7030, weight-average molecular weight: 9700) A-4: Novolac-type phenolic resin (manufactured by Asahi Organic Chemicals Co., Ltd., product name: TR4080G, weight-average molecular weight: 4704) A-5: 2,6-Bis(2,4-dihydroxybenzyl)4-methylphenol (manufactured by Asahi Organic Chemicals Co., Ltd., product name: BIR-PC) B-1: 1,3,4,6-Tetrakis(methoxymethyl)glycoluryl (manufactured by Sanwa Chemical Co., Ltd., product name: Nikalac MX-270) C-1: Photoacid generator (manufactured by Sunapro Co., Ltd., product name: NA-CS1) C-2: Photoacid generator (manufactured by BASF Corporation, product name: Irgacure PAG121) D-1: Triethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) E-1: 3-Trimethoxysilylpropyl succinic anhydride (manufactured by Shin-Etsu Chemical Co., Ltd., product name: X-12-967C) F-1: Silicone-based surfactant (manufactured by Dow Toray Corporation, product name: DOWSIL SH29 Paint Additive) G-1: Propylene glycol monomethyl ether acetate (manufactured by Tokyo Chemical Industry Co., Ltd., product name: Propylene glycol 1-monomethyl ether 2-acetate) G-2: γ-Butyrolactone (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0127] <Resolution Evaluation> The photosensitive resin compositions obtained in the examples and comparative examples were spin-coated onto 6-inch silicon wafers and heated on a hot plate at 90°C for 3 minutes to produce a coating with a thickness of 3.0 μm. The prepared coating was then exposed to i-line (365 nm) light at an exposure dose of 20-335 mJ / cm² using an i-line stepper (Nikon Corporation, product name: NSR-2205i12D). 2 Within the range of 5 mJ / cm 2 Reduction projection exposure was performed in increments using a mask. The mask was formed with a pattern such that the width of the exposed and unexposed areas was 1:1, in increments of 0.5 μm:0.5 μm to 30 μm:30 μm. In the range of 0.5 μm:0.5 μm to 2.0 μm:2.0 μm, the pattern was formed in increments of 0.1 μm; in the range of 2 μm:2 μm to 10 μm:10 μm, the pattern was formed in increments of 1 μm; and in the range of 10 μm:10 μm to 30 μm:30 μm, the pattern was formed in increments of 10 μm.

[0128] Next, the exposed coating film was heated under the temperature and time conditions shown in the "PEB" column of Table 1 (post-exposure bake). A 2.38% by mass aqueous solution of tetramethylammonium hydroxide (manufactured by Tama Chemical Industry Co., Ltd., product name: TMAH2.38% by mass) was used as the developer, and the unexposed areas were removed from the photosensitive layer (coating film) using a paddle method with a 23°C developer at the development time shown in Table 1 (manufactured by Takizawa Sangyo Co., Ltd., product name: AD-1200). In the table, "40×2" means that 40-second paddle development was performed twice, and "300×2" means that 300-second paddle development was performed twice. Here, the development time in each example and comparative example was set to a time that allowed for the removal of the unexposed areas. Next, the developer was washed away by spraying purified water at 23°C (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name: Purified Water) for 30 seconds (pump discharge pressure [rinsing solution]: 0.12~0.14 MPa). Then, the resin pattern was formed by drying. Next, the resin pattern was cured by heat treatment at 180°C for 60 minutes in a solvent drying safety-specification constant temperature oven (manufactured by Kusumoto Kasei Co., Ltd., product name: HG220).

[0129] The resin patterns formed in this manner were observed using a microscope (Keyence Corporation, product name: VHX-8000) at a magnification of 1000x. The smallest space width among the patterns in which the empty areas (unexposed areas) were cleanly removed and the line areas (exposed areas) were formed without meandering or missing parts was defined as the minimum resolution. Table 1 shows the observation results for the exposure level that showed the smallest resolution among all exposure levels. The exposure level that showed the smallest resolution is also shown in Table 1.

[0130] [Table 1] [Explanation of Symbols]

[0131] 1...Substrate, 2...Photosensitive layer, 3...Circuit groove, 4...Resin pattern, 5...Seed metal layer, 6...Plating layer, 7...Conductor layer, 8...Conductor pattern.

Claims

1. (A) Component: Resin having phenolic hydroxyl groups, (B) Component: A compound having a methylol group or an alkoxyalkyl group, (C) Ingredients: Photoacid generator, It contains, A photosensitive resin composition comprising a resin having structural units derived from hydroxystyrene, wherein component (A) is a photosensitive resin composition.

2. The photosensitive resin composition according to claim 1, wherein the content of structural units derived from hydroxystyrene in the resin having structural units derived from hydroxystyrene is 80 mol% or more based on the total amount of structural units constituting the resin.

3. The photosensitive resin composition according to claim 1, wherein the resin having structural units derived from hydroxystyrene further has structural units derived from styrene.

4. (a) A step of applying the photosensitive resin composition according to any one of claims 1 to 3 onto a substrate and drying the photosensitive resin composition to form a photosensitive layer, (b) A step of exposing the photosensitive layer in a predetermined pattern, developing it, and further heating it to obtain a resin pattern, (c) A step of forming a conductive layer by plating the exposed portion of the substrate and the exposed portion of the resin pattern, (d) A step of removing a portion of the conductor layer to form a conductor pattern, A method for manufacturing a circuit board equipped with the following features.

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