Organometallic compounds, photosensitive materials for photoresists, and photoresists

Abstract

To provide an organometallic compound suitable for resist materials that enable the formation of a resist film with high-resolution patterns and superior etching resistance through exposure to ultrashort-wavelength light.SOLUTION: An organometallic compound according to the present invention has a structure in which a 1,8-naphthalimide derivative (for example, 3-hydroxy-1,8-naphthalimide-p-toluenesulfonate) or a 1,3-dioxoisoindoline derivative (for example, 4-hydroxy-1,3-dioxoisoindoline-2-ylmethanesulfonate) is coordinated to a metal or metal oxide (for example, HfO2).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a novel organometallic compound, a photosensitive material for photoresists containing the organometallic compound, and a photoresist containing the organometallic compound. [Background technology]

[0002] In the manufacturing of semiconductor devices, a method is used in which a resist film with a pattern is formed using a photoresist (chemically amplified photoresist) containing a photosensitive resin and a photoacid generator, which has the property of changing its solubility in the developer solution upon exposure, and the substrate is etched (for example, dry etching using reactive gas or plasma) using the obtained resist film. As the pattern becomes smaller, the exposure wavelength is becoming shorter.

[0003] Patent Document 1 describes that when a positive-type resist resin containing triphenylsulfonium trifluoromethanesulfonate, which is a photoacid generator, and a photosensitive resin is irradiated with KrF excimer laser light (wavelength 248 nm), fine patterns can be formed with high precision. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-177541 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In recent years, further miniaturization, increased capacity, and performance improvements have necessitated even finer pattern design in electronic devices. Therefore, the use of ultrashort wavelength light, such as extreme ultraviolet (EUV; wavelength 13.5 nm), as exposure light is being considered.

[0006] However, since light rays with ultra-short wavelengths are easily absorbed by the photoresist and it is difficult for the light rays to reach the bottom of the resist film when the resist film is thick, it has been difficult to form a pattern with good accuracy. Further, although reducing the thickness of the resist film can improve the pattern accuracy, the problem has been that the etching resistance decreases.

[0007] Therefore, an object of the present invention is to provide an organometallic compound suitable for a resist material that forms a resist film having a high-resolution pattern and excellent etching resistance by exposing the resist film to light rays with ultra-short wavelengths. Another object of the present invention is to provide a resist material that forms a resist film having a high-resolution pattern and excellent etching resistance by exposing the resist film to light rays with ultra-short wavelengths. Another object of the present invention is to provide a resist that forms a resist film having a high-resolution pattern and excellent etching resistance by exposing the resist film to light rays with ultra-short wavelengths.

Means for Solving the Problems

[0008] As a result of intensive studies by the present inventors to solve the above problems, it has been found that an organometallic compound formed by bonding a compound represented by the following formula (2a) or (2b) to a metal or metal oxide (1) has a photoreactivity of rapidly aggregating to form aggregates (or lumps) even when the irradiated light rays are light rays with ultra-short wavelengths. The present invention has been completed based on this finding.

[0009] That is, the present invention provides an organometallic compound having a structure in which a compound represented by the following formula (2a) or (2b) is coordinately bonded to a metal or metal oxide (1).

Chemical formula

[0010] The present invention also relates to the R in the above formula. 2 The present invention provides an organometallic compound which is a hydroxyl group, a carboxyl group, a phosphate group, a phosphate monoester group, a sulfonic acid group, a sulfino group, a triazole group, or a tetrazole group.

[0011] The present invention also provides the organometallic compound wherein (1) is at least one selected from hafnium, zirconium, tin, cobalt, palladium, antimony, and oxides thereof.

[0012] The present invention also provides a photosensitive material for photoresists containing the organometallic compound.

[0013] The present invention also provides a photosensitive material for photoresists, which is a photosensitive material for extreme ultraviolet light or an electron beam.

[0014] The present invention also provides a photoresist comprising the organometallic compound and a solvent. [Effects of the Invention]

[0015] The organometallic compound of the present invention is an organic-inorganic composite having a structure in which a ligand is coordinated to a metal or metal oxide (1), and exhibits good solubility in solvents. Furthermore, the organometallic compound has excellent photoresponsiveness, and when irradiated with light, it efficiently senses even ultrashort wavelength light and forms aggregates. The aggregates of the organometallic compound no longer exhibit solubility in solvents. Moreover, because the aggregates have a structure in which metal or metal oxide (1) is aggregated, they have toughness that can withstand etching. Therefore, if a layer containing the organometallic compound in a highly dispersed state is thinned to a thickness that allows ultrashort wavelength light to reach the bottom, and then exposed to a pattern shape using ultrashort wavelength light, followed by washing with a solvent, the organometallic compound in the unexposed areas will be washed away, but the organometallic compound in the exposed areas will aggregate and remain without being washed away, thus enabling the precise manufacture of a resist film with a high-resolution fine pattern. Furthermore, the resist film obtained in this way possesses etching resistance even when thin. By using the resist film manufactured by the above method to perform etching (for example, dry etching using reactive gas or plasma) on a substrate, semiconductor devices with high-resolution patterns (e.g., wiring patterns, circuit patterns, etc.) can be manufactured with a high yield. [Modes for carrying out the invention]

[0016] [Organometallic compound] The organometallic compounds of the present invention are compounds having a structure in which a compound represented by the following formula (2a) or (2b) is coordinately bonded to a metal or metal oxide (1).

[0017] The organometallic compound of the present invention comprises at least a metal or metal oxide (1) and a ligand derived from a compound represented by the following formula (2a) or (2b).

[0018] The organometallic compound of the present invention is an organic-inorganic composite obtained by reacting a metal or metal oxide (1) with a complexing agent (2), wherein the complexing agent (2) includes at least a compound represented by the following formula (2a) or (2b).

[0019] The organometallic compound may contain components other than the metal or metal oxide (1) and ligands derived from the complexing agent (2). However, the proportion of the total weight of the ligands derived from the metal or metal oxide (1) and the complexing agent (2) in the total amount (100% by weight) of the organometallic compound is, for example, 60% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, particularly preferably 90% by weight or more, most preferably 95% by weight or more, and especially preferably 99% by weight or more. The upper limit is 100% by weight.

[0020] The aforementioned organometallic compounds exhibit excellent solubility (or dispersibility) in solvents, and their average particle size (particle size determined by dynamic light scattering) in a solvent (e.g., PGMEA) is, for example, 200 nm or less, preferably 100 nm or less, and particularly preferably 50 nm or less. The lower limit is, for example, 1 nm.

[0021] The organometallic compound has excellent sensitivity to light, and upon irradiation with light, it generates acid (HX) and rapidly aggregates. The wavelength of the light is, for example, 100 nm or less (e.g., 0 to 100 nm), preferably 80 nm or less, particularly preferably 50 nm or less, most preferably 30 nm or less, and especially preferably 20 nm or less. The light includes, for example, X-rays, electron beams (EB), EUV, etc.

[0022] (Metal or metal oxide (1)) The metal or metal oxide (1) is a component that forms the core of the organometallic compound and includes at least one selected from metals and metal oxides.

[0023] Examples of the aforementioned metals include hafnium, zirconium, tin, cobalt, palladium, antimony, titanium, and aluminum.

[0024] The metal oxide includes the oxide of the metal and its partial hydroxide (or hydrate). Examples of the metal oxide include hafnium oxide (HfO2), zirconium oxide (ZrO2, Zr6O4(OH)4), tin oxide (SnO2, Sn2O3, Sn3O4, Sn6O 12 Sn 12 O 25 H 16 (C4H9Sn) 12 O 14 (OH)6), cobalt oxide (CoO, Co2O3, Co3O4), palladium oxide (PdO), antimony oxide (Sb2O3), titanium oxide (TiO2), aluminum oxide (Al2O3), and the like.

[0025] The metal oxide can be produced, for example, by the sol-gel method. Specifically, starting from a metal alkoxide, through hydrolysis and polycondensation reactions, passing through a sol / gel state, and finally obtaining a metal oxide.

[0026] The shape of the metal or metal oxide (1) is not particularly limited. Examples include spherical (true spherical, substantially spherical, ellipsoidal, etc.), polyhedral, rod-shaped (cylindrical, prismatic, etc.), flat plate-shaped, flaky, irregular-shaped, and the like. Also, the metal or metal oxide (1) may be hollow, porous, or solid.

[0027] The average particle diameter of the metal or metal oxide (1) (the particle diameter determined by the dynamic light scattering method) is, for example, 1 to 200 nm, preferably 2 to 100 nm, and particularly preferably 2 to 50 nm.

[0028] In the total amount of the organometallic compound (or the total weight of the ligand derived from the compound represented by the following formula (2a) or (2b) and the metal or metal oxide (1)), the proportion occupied by the metal or metal oxide (1) is, for example, 10 to 90% by weight, preferably 30 to 70% by weight.

[0029] (Complexing agent (2)) The complexing agent (2) contains at least a compound represented by the following formula (2a) or (2b). [ka] (In the formula, R 1 -L-(R 2 ) n The group represented by is a substituent of the aromatic ring shown in the formula, where L represents a single bond or a linking group, and R represents a single bond or a linking group. 2 The symbol (1) represents a coordinating group that coordinates to (1) above, and n is an integer of 1 or more. (The aromatic ring shown in the formula may have substituents other than the aforementioned group.)

[0030] The hydrocarbon groups include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and groups in which two or more of these are linked by a single bond.

[0031] The aliphatic hydrocarbon group has 1 to 5 carbon atoms (=C 1-5 Aliphatic hydrocarbon groups are preferred, for example alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, and pentyl groups; and alkenyl groups such as vinyl, allyl, and 1-butenyl groups.

[0032] The aforementioned alicyclic hydrocarbon group is C 3-10 Alicyclic hydrocarbon groups are preferred, for example, cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups; cycloalkenyl groups such as cyclopentenyl and cyclohexenyl groups; perhydronaphthalene-1-yl, norbornyl, adamantyl, and tricyclo[5.2.1.0 2,6 ] Decane-8-yl group, tetracyclo[4.4.0.1 2,5 .1 7,10 Examples include bridged cyclic hydrocarbon groups such as dodecane-3-yl groups.

[0033] The aforementioned aromatic hydrocarbon group is C 6-14 (Especially C 6-10 Aromatic hydrocarbon groups are preferred, for example, aryl groups such as phenyl groups and naphthyl groups.

[0034] Examples of substituents that the hydrocarbon group may have include halogen atoms, oxo groups, carboxyl groups, and groups represented by the following formula (r). -X 1 -R (r) (In formula (r), X 1 represents -O-, -S-, or -CO-, and R represents a hydrocarbon group or a halogenated hydrocarbon group. (The bond emanating from the left end of formula (r) is bonded to a carbon atom constituting the naphthalene ring structure in formula (2a), or to a carbon atom constituting the benzene ring structure in formula (2b).)

[0035] The halogen atom is preferably a fluorine atom or an iodine atom, and particularly preferably a fluorine atom.

[0036] Examples of hydrocarbon groups in R are the same as those described above.

[0037] Examples of halogenated hydrocarbon groups in R include groups in which at least one hydrogen atom of the hydrocarbon group is substituted with a halogen atom (for example, a fluorine atom and / or an iodine atom).

[0038] The L in the above-mentioned L represents a single bond or a linking group. The linking group is a divalent group having one or more atoms, and examples include a divalent hydrocarbon group, a carbonyl group (-CO-), an ether bond (-O-), a thioether bond (-S-), an ester bond (-COO-), an amide bond (-CONH-), a carbonate bond (-OCOO-), and a group formed by linking multiple such groups.

[0039] The aforementioned divalent hydrocarbon groups include linear hydrocarbon groups and cyclic hydrocarbon groups. Examples of the linear hydrocarbon groups include linear or branched alkylene groups having 1 to 5 carbon atoms, such as methylene, methylmethylene, dimethylmethylene, ethylene, propylene, and trimethylene; and linear or branched alkenylene groups having 2 to 5 carbon atoms, such as vinylene, 1-methylvinylene, propenylene, 1-butenylene, 2-butenylene, 1-pentenylene, and 2-pentenylene. Examples of the aforementioned cyclic hydrocarbon groups include cycloalkylene groups having 3 to 18 carbon atoms, such as 1,2-cyclopentylene, 1,3-cyclopentylene, cyclopentylidene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, and cyclohexylidene; and arylene groups having 6 to 14 carbon atoms, such as o-phenylene, m-phenylene, p-phenylene, and naphthylene.

[0040] Among the divalent hydrocarbon groups, chain-like hydrocarbon groups are preferred in that they improve photosensitivity to ultrashort wavelength light, and linear or branched alkylene groups having 1 to 5 carbon atoms are particularly preferred.

[0041] As for L, in terms of improving photosensitivity to ultrashort wavelength light, a carbonyl group (-CO-), an ether bond (-O-), a thioether bond (-S-), an ester bond (-COO-,-OCO-), or a divalent group formed by linking these groups with a divalent hydrocarbon group (preferably a chain-like hydrocarbon group, particularly preferably an alkylene group, most preferably an alkylene group having 1 to 5 carbon atoms), or a single bond is preferred.

[0042] The aforementioned R 2R is a coordinating group having the property of coordinating to (1) above, and examples include a hydroxyl group, a carboxyl group, a phosphate group (P(=O)(OH)2), a phosphate monoester group (P(=O)(OH)(OR'); R' represents a hydrocarbon group, and examples similar to those above can be given), a sulfonic acid group (S(=O)2(OH)), a sulfino group (S(=O)OH), a triazole group (for example, a group represented by the following formula (az-1) or (az-2)), a tetrazole group (for example, a group represented by the following formula (az-3)), etc. The bond indicated by the wavy line in the following formula is bonded to the group represented by L in the above formula (2a) or (2b). [ka]

[0043] The aforementioned n is R that binds to the aforementioned L. 2 This indicates the number of R, which is an integer greater than or equal to 1 (for example, an integer between 1 and 3, preferably 1 or 2). If n is an integer greater than or equal to 2, then there are two or more R 2 These can be the same or different.

[0044] The aforementioned R 2 In terms of improving photosensitivity to ultrashort wavelength light, hydroxyl groups, carboxyl groups, phosphate groups, phosphate monoester groups, or sulfonic acid groups are preferred.

[0045] The aromatic rings shown in formulas (2a) and (2b) above are the -L-(R 2 ) n In addition to the group represented by (r), the group may have one or more substituents (for example, 1 to 3). Examples of such substituents include halogen atoms, hydrocarbon groups, halogenated hydrocarbon groups, and the group represented by formula (r). Examples of the hydrocarbon group and halogenated hydrocarbon group are the same as those described above.

[0046] The complexing agent (2) preferably includes at least a compound represented by formula (2a) above, in that it improves photosensitivity to ultrashort wavelength light, and in particular, it is preferable that the compound represented by formula (2a) above includes a compound in which L in the formula is a carbonyl group (-CO-), an ether bond (-O-), a thioether bond (-S-), an ester bond (-COO-), or a divalent group formed by linking these groups with an alkylene group (for example, a linear or branched alkylene group having 1 to 5 carbon atoms), or a single bond.

[0047] The complexing agent (2) may also contain one or more other complexing agents in addition to the compound represented by formula (2a) or (2b).

[0048] Other complexing agents include, for example, carboxylic acids, phosphoric acids, phosphonic acids, and sulfonic acids.

[0049] Examples of the carboxylic acid include citric acid, oxalic acid, malic acid, maleic acid, tartaric acid, glutaric acid, adipic acid, pimelic acid, succinic acid, malonic acid, fumaric acid, phthalic acid, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, glycolic acid, glyceric acid, lactic acid, etc. 1-10 Alkyl carboxylic acids; such as acrylic acid, methacrylic acid, 2-methylisocrotonic acid, 3-methylcrotonic acid, etc. 2-10 Alkenyl carboxylic acids; such as benzoic acid, salicylic acid, and crotonic acid. 6-10 Examples include aryl carboxylic acids.

[0050] Examples of the aforementioned phosphoric acid include methyl phosphate, ethyl phosphate, propyl phosphate, butyl phosphate, hexyl phosphate, phenyl phosphate, dimethyl phosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, and dihexyl phosphate. 1-10 Alkyl phosphates; diphenyl phosphates, etc. 6-10 Examples include aryl phosphates.

[0051] Examples of the phosphonic acid include methylphosphonic acid, ethylphosphonic acid, propylphosphonic acid, butylphosphonic acid, hexylphosphonic acid, etc. 1-10 Alkylphosphonic acid; vinylphosphonic acid, etc. 2-10 Alkenylphosphonic acid; phenylphosphonic acid, etc. 6-10 Arylphosphonic acids are one example.

[0052] Examples of the aforementioned sulfonic acid include methylsulfonic acid, ethylsulfonic acid, propylsulfonic acid, butylsulfonic acid, hexylsulfonic acid, etc. 1-10 Alkyl sulfonic acid; C such as phenyl sulfonic acid 6-10 Aryl sulfonic acid; vinyl sulfonic acid, etc. 2-10 Alkenyl sulfonic acid is one example.

[0053] Among other complexing agents, C is particularly noteworthy for its ability to impart good dispersibility to organometallic compounds. 6-10 Preferably, a carboxylic acid, phosphoric acid, phosphonic acid, or sulfonic acid having an aryl group is preferred, and especially C 6-10 Arylcarboxylate salts are preferred.

[0054] When the complexing agent (2) contains a compound represented by formula (2a) or (2b) along with other complexing agents, the proportion of the compound represented by formula (2a) or (2b) in the total amount of the complexing agent (2) (the total proportion if it contains both the compound represented by formula (2a) and the compound represented by formula (2b)) is, for example, 0.1% by weight or more, preferably 0.5% by weight or more, and particularly preferably 1.0% by weight or more. The upper limit is, for example, 50% by weight, preferably 30% by weight.

[0055] In the total amount of the organometallic compound (or the total weight of the metal or metal oxide (1) and the ligand), the proportion of ligands derived from the compound represented by formula (2a) or (2b) (the total proportion if it includes ligands derived from the compound represented by formula (2a) and ligands derived from the compound represented by formula (2b)) is, for example, 0.1 to 50% by weight, preferably 0.5 to 30% by weight.

[0056] Furthermore, the amount of ligands derived from the compound represented by formula (2a) or (2b) above (the total amount if it includes ligands derived from the compound represented by formula (2a) and ligands derived from the compound represented by formula (2b) above) is, for example, 0.1 to 50 parts by weight, preferably 0.5 to 30 parts by weight, and particularly preferably 1 to 20 parts by weight, per 100 parts by weight of metal or metal oxide (1).

[0057] The aforementioned organometallic compound aggregates when irradiated with light. The aggregation mechanism is thought to be as follows: Although the metal or metal oxide (1) is a fine particle and has a tendency to aggregate, the organometallic compound has compounds represented by formula (2a) or (2b) bound to the surface of the metal or metal oxide (1), thereby suppressing aggregation between the metal or metal oxide (1) particles and achieving dispersibility. When irradiated with light, it is thought that the number of bound ligands decreases through the reactions 1, 2, and 3 below, resulting in a loss of dispersibility and the formation of aggregates. 1. A portion of the compound represented by formula (2a) or (2b) decomposes into acid (R 1 It generates -SO3H). 2. The acid generated (R 1 -SO3H) reacts with organometallic compounds, causing ligands bonded to the surface of the metal oxide (1) to be detached. 3. A metal or metal oxide (1) loses its dispersibility due to a decrease in the number of ligands bonded to its surface.

[0058] The following shows the aggregation reaction of organometallic compounds when using the compound represented by formula (2a-1), which is an example of a compound represented by formula (2a), as the complexing agent (2). [ka] (In the formula, R 1 , L is R in equation (2a) 1 It is the same as L. Furthermore, the carbon atoms constituting the naphthalene ring structure in the formula may have substituents attached to them other than the group represented by -L-COOH shown in the formula.

[0059] In the following formulas, M represents a metal or metal oxide (1). In the following formulas, R represents the portion enclosed by the dashed line of the ligand that forms a coordinate bond with M in the following formula (= ligand derived from the compound represented by formula (2a-1) above). [ka]

[0060] [Method for producing organometallic compounds] The organometallic compound can be produced, for example, by mixing a metal or metal oxide (1) with a complexing agent (2) containing at least a compound represented by formula (2a) or (2b) in a solvent.

[0061] The following schematic diagram illustrates the reaction that produces the organometallic compound, using the compound represented by formula (2a-1) above as the complexing agent (2).

[0062] [ka]

[0063] In the above formula, M represents a metal or a metal oxide (1). In the above equation (2a-1), R 1 , L is R in equation (2a) 1 , is the same as L. In addition, the carbon atoms constituting the naphthalene ring structure in formula (2a-1) may have substituents attached to them other than the group represented by -L-COOH shown in the formula. Formula (3) above represents an organometallic compound in which a ligand derived from the compound represented by formula (2a-1) above is coordinately bonded to the surface of a metal or metal oxide (1), and R in the formula represents the portion enclosed by the dashed line (i.e., the portion other than the carboxyl group) of the compound represented by formula (2a-1) below.

[0064] The amount of complexing agent (2) used is, for example, 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, per 1 part by weight of the above-mentioned metal or metal oxide (1).

[0065] The amount of the compound represented by formula (2a) or (2b) used (the total amount if both the compound represented by formula (2a) and the compound represented by formula (2b) are used) is, for example, 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, per 1 part by weight of the above metal or metal oxide (1).

[0066] Examples of the aforementioned solvents include ethers such as diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, cyclopentyl methyl ether, propylene glycol methyl ether, and propylene glycol monomethyl ether acetate. These can be used individually or in combination of two or more.

[0067] The amount of solvent used is, for example, about 50 to 300% by weight relative to the total amount of metal or metal oxide (1) and complexing agent (2).

[0068] After this reaction is complete, the resulting reaction product can be separated and purified by general precipitation, washing, and filtration procedures.

[0069] [Photosensitive material for photoresists] The aforementioned photosensitive material for photoresists is a photosensitive material used in the field of photolithography (for example, a compound whose solubility in a solvent changes upon irradiation with light), and includes the organometallic compound described above.

[0070] The photosensitive material for photoresist may contain other components besides the organometallic compounds described above, but the proportion of the organometallic compounds in the total amount of the photosensitive material for photoresist is, for example, 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, particularly preferably 95% by weight or more, most preferably 99% by weight or more, and especially preferably 99.9% by weight or more. The upper limit is 100% by weight.

[0071] The photosensitive material for photoresist exhibits excellent solubility (or dispersibility) in solvents (e.g., PGMEA). The average particle size (particle size determined by dynamic light scattering) of the photosensitive material for photoresist in the solvent is, for example, 200 nm or less, preferably 100 nm or less, and particularly preferably 50 nm or less. The lower limit is, for example, 1 nm.

[0072] Furthermore, the photosensitive material for photoresist exhibits excellent sensitivity to ultrashort wavelength light, and upon irradiation with such light, it quickly forms aggregates. The wavelength of the light is, for example, 100 nm or less, preferably 80 nm or less, and particularly preferably 50 nm or less. The light includes, for example, X-rays, electron beams (EB), EUV, etc.

[0073] The aforementioned photosensitive material for photoresists possesses thermal stability, and aggregation is suppressed even when subjected to heat treatment (for example, heating at a temperature of 50°C to less than 130°C for 1 to 5 minutes). Therefore, the coating film containing the aforementioned photosensitive material for photoresists can be heat-dried while suppressing aggregation, resulting in excellent workability.

[0074] Because the aforementioned photosensitive material for photoresists has the above-described characteristics, it can be suitably used as a photosensitive material for negative-type photoresists. Furthermore, it can be suitably used as a photosensitive material for photoresists that use ultrashort wavelength light such as extreme ultraviolet light or electron beams.

[0075] [Photoresist] The photoresist of the present invention is a resist used in the field of photolithography for forming a patterned resist film, and comprises the above-mentioned organometallic compound and a solvent, wherein the organometallic compound is contained in the solvent in a dissolved (or highly dispersed) state.

[0076] In the photoresist, the organometallic compound is contained in a stably dissolved (or highly dispersed) state. The average particle size of the organometallic compound in the photoresist (particle size determined by dynamic light scattering) is, for example, 200 nm or less, preferably 100 nm or less, and particularly preferably 50 nm or less. The lower limit is, for example, 1 nm. Therefore, by using the photoresist, a resist film with a low LER and high resolution fine pattern can be obtained.

[0077] Examples of the aforementioned solvents include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; and (poly)C such as ethylene glycol monoacetate, diethylene glycol monoacetate, diethylene glycol diacetate, propylene glycol monoacetate, propylene glycol diacetate, and dipropylene glycol monoacetate. 1-5 Alkylene glycol esters; (poly)C such as ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol n-propyl ether, propylene glycol phenyl ether, tripropylene glycol methyl-n-propyl ether, etc. 1-5 Alkylene glycol ethers; (poly)C such as ethylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), etc. 1-5Examples include alkylene glycol ether esters; cyclic ethers such as dioxane; esters such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; aromatic hydrocarbons such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenethole, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, and mesitylene; and dimethyl sulfoxide. These can be used individually or in combination of two or more.

[0078] The content of the organometallic compound is, for example, 0.5 to 50% by weight, preferably 1.0 to 30% by weight, of the total amount (100% by weight) of the photoresist.

[0079] The solvent content is, for example, 50 to 99.5% by weight, preferably 70 to 99% by weight, of the total amount of the photoresist (100% by weight).

[0080] The photoresist may contain other components besides the organometallic compound and solvent, such as a leveling agent or a quencher.

[0081] In the total amount (100% by weight) of the photoresist, the proportion of the total weight of the organometallic compound and the solvent is, for example, 60% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, particularly preferably 90% by weight or more, most preferably 95% by weight or more, and especially preferably 99% by weight or more. The upper limit is 100% by weight.

[0082] The photoresist contains at least the organometallic compound as nonvolatile content. The proportion of the organometallic compound in the total amount of nonvolatile content (100% by weight) is, for example, 60% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, particularly preferably 90% by weight or more, most preferably 95% by weight or more, and especially preferably 99% by weight or more. The upper limit is 100% by weight.

[0083] In this specification, the non-volatile components of a photoresist refer to the components containing the organometallic compound, for example, the components remaining after heating the photoresist at 100°C for 1 hour under normal pressure.

[0084] Furthermore, the photoresist is irradiated with light (the integrated light intensity is, for example, 5 to 500 mJ / cm²). 2 If this is done, the organometallic compounds contained in the photoresist will quickly form aggregates. Furthermore, from the viewpoint of further refining the pattern, it is preferable to shorten the wavelength of the light, for example, 100 nm or less (for example, 1 to 100 nm) is preferred, 80 nm or less is more preferred, 50 nm or less is particularly preferred, 30 nm or less is most preferred, and 20 nm or less is especially preferred. The light includes, for example, X-rays, electron beams (EB), EUV, etc.

[0085] Because the aforementioned photoresist has the above-described characteristics, it can be suitably used as a negative-type photoresist. Furthermore, it can be suitably used as a photolithography resist using ultrashort wavelength light such as extreme ultraviolet light or electron beams.

[0086] By using the aforementioned photoresist, for example, a resist film with a fine pattern that is highly accurate and has excellent etching resistance can be formed through the following steps 1 to 3.

[0087] Step 1: A step of applying and drying the photoresist onto a substrate to form an organometallic compound layer. Step 2: A step of transferring a pattern by irradiating the organometallic compound layer with light. Step 3: Development process

[0088] (Process 1) This process involves applying the photoresist onto the substrate to be etched and drying it to form an organometallic compound layer. Through this process, a [substrate / organometallic compound layer] laminate is obtained.

[0089] For coating the photoresist, known methods such as spin coating, curtain coating, roll coating, spray coating, and screen printing can be used.

[0090] The substrate on which the photoresist is coated may be subjected to surface treatment as needed. For example, an adhesion agent such as hexamethyldisilazane (HMDS) may be applied to the surface of the substrate to improve the adhesion of the resist film.

[0091] The photoresist coating can be dried by natural drying, but because the organometallic compound has thermal stability, it can also be dried by heating (for example, heating at a temperature of 50°C to less than 130°C for 1 to 5 minutes), which offers excellent workability.

[0092] The thickness of the organometallic compound layer is, for example, 1000 nm or less, preferably 100 nm or less. The lower limit of the thickness is, for example, 1 nm. The aggregate of the organometallic compound contains a metal or metal oxide and therefore possesses toughness. For this reason, even if the organometallic compound layer is thinned, a resist film with excellent etching resistance can be formed.

[0093] (Process 2) This step involves transferring a pattern to the organometallic compound layer obtained in step 1 by irradiating it with light, for example, by irradiating it with light through a photomask having a pattern.

[0094] When light is irradiated through a photomask with a pattern, the organometallic compounds in the exposed areas aggregate and adhere to the substrate, while the organometallic compounds in the unexposed areas do not aggregate and maintain their solubility.

[0095] While there are no particular restrictions on the light beam used for irradiation, as long as it can initiate the aggregation of organometallic compounds contained in the coating film, using an ultrashort wavelength light source such as EUV or electron beams is preferable because it allows for the precise transfer of extremely fine patterns.

[0096] Furthermore, because the aggregates of the organometallic compound are tough, etching resistance can be maintained even when the organometallic compound layer is thinned. By thinning the organometallic compound layer and irradiating it with ultrashort wavelength light, the light can reach the bottom of the organometallic compound layer, allowing for the formation of a highly accurate pattern.

[0097] (Step 3) This process involves subjecting the [substrate / organometallic compound layer] laminate, after light irradiation, to a development treatment. During the development treatment, the unexposed parts of the organometallic compound layer are washed away, while the exposed parts remain in close contact with the substrate.

[0098] For the developing process, alkaline aqueous solutions or organic solvents can be used, either individually or in combination of two or more.

[0099] Examples of the aforementioned alkaline aqueous solutions include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, aqueous ammonia, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene.

[0100] Examples of the organic solvent include those similar to those used in photoresists. In particular, it is preferable to include at least one selected from polyhydric alcohols, esters, ethers, ketones, and aromatic hydrocarbons, especially to include at least an ester, and most preferably to include at least butyl acetate.

[0101] Examples of development methods include applying the developer solution to the [substrate / organometallic compound layer] laminate by methods such as dipping, showering, or spraying.

[0102] The temperature of the developing solution is, for example, 25-40°C. The development time is determined appropriately depending on the thickness of the organometallic compound layer, but is typically around 0.5-5 minutes.

[0103] Ideally, unexposed areas should be completely removed during the development process. This is because the presence of development residue can easily lead to problems such as abnormal wiring shapes. The photoresist of the present invention contains organometallic compounds that possess high dispersibility and thermal stability, so unexposed areas can be easily and completely removed by washing with a developer solution, and no development residue is generated. Therefore, products without defects can be manufactured with a high yield.

[0104] After step 3, a resist film can be formed on the substrate that has a fine pattern with high precision and excellent etching resistance, consisting of aggregates of organometallic compounds. By etching the substrate using the resist film thus obtained, high-precision electronic devices can be manufactured.

[0105] The aforementioned electronic devices include, for example, display devices such as organic EL displays and liquid crystal displays; input devices such as touch panels; light-emitting devices; sensor devices; and MEMS (Micro Electro Mechanical Systems) devices such as optical scanners, optical switches, accelerometers, pressure sensors, gyroscopes, microfluidics, and inkjet heads.

[0106] The configurations and combinations thereof described above are merely examples, and additions, omissions, substitutions, and modifications to the configurations are permitted as appropriate, without departing from the spirit of the present invention. [Examples]

[0107] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples.

[0108] Example 1 <Synthesis of 3-hydroxy-1,8-naphthalimido-p-toluenesulfonate> 5.5 g of 3-hydroxy-1,8-naphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 5.9 g of di-tert-butyl dicarbonate (manufactured by Tokyo Chemical Industry Co., Ltd.) were dispersed in 32 g of acetonitrile, and 2.2 g of pyridine was added and the mixture was stirred at 50°C for 2 hours. After cooling to room temperature, the solution was placed in water and the precipitate was filtered off to obtain a white solid. The obtained white solid was washed with water and dried to obtain 8.1 g of 3-tert-butoxycarbonyloxy-1,8-naphthalic anhydride. 8.1 g of the obtained 3-tert-butoxycarbonyloxy-1,8-naphthalic anhydride was dissolved in 137 g of acetonitrile, and 2.0 g of aqueous hydroxylamine solution (manufactured by Tokyo Chemical Industry Co., Ltd., 50% aqueous solution) was added and the mixture was stirred at room temperature for 2 hours. After this, the reaction mixture was added to water and the precipitate was filtered off to obtain 8.0 g of 3-t-butoxycarbonyloxy-N-hydroxy-1,8-naphthalimide as a white solid. 3.3 g of the obtained 3-t-butoxycarbonyloxy-N-hydroxy-1,8-naphthalimide was mixed with 33 mL of dichloromethane and stirred with a magnetic stirrer. The reaction mixture was then placed in an ice bath. Subsequently, 2.1 g of p-toluenesulfonate was added to the reaction mixture, followed by 1.2 g of pyridine, which was slowly added. The mixture was then heated to room temperature to complete the reaction. The mixture was then placed in an ice bath again, and 3.1g of concentrated hydrochloric acid was added. The reaction was completed by immersing this solution in a 50°C warm bath. The precipitate was filtered, thoroughly washed with deionized water, and dried in a vacuum dryer at 60°C. This yielded 3.1 g of yellow solid 3-hydroxy-1,8-naphthalimide-p-toluenesulfonate (P-1).

[0109] <Synthesis of organometallic compounds> Three g of hafnium isopropoxide, used as a metal oxide raw material, was dissolved in 20 g of THF. A solution containing four g of benzoic acid and one g of 3-hydroxy-1,8-naphthalimide-p-toluenesulfonate (P-1) in addition to 20 g of THF was added to this solution at room temperature to obtain a mixed solution. To the resulting mixed solution, 2 mL of deionized water was added under temperature control at 65°C, and a sol-gel reaction was carried out for 24 hours. After the reaction was complete, the precipitate was collected and washed with acetone / water (1 / 4 volume ratio). It was then dried under vacuum at 40°C for 24 hours. This yielded an organometallic compound.

[0110] <Synthesis of photoresists> 0.1 g of the obtained organometallic compound was dissolved in 3.0 g of PGMEA, and then filtered through a 0.20 μm pore size filter to remove undissolved aggregates. This yielded a photoresist.

[0111] Example 2 <Synthesis of 3-hydroxy-1,8-naphthalimidotrifluoromethanesulfonate> 3-t-butoxycarbonyloxy-N-hydroxy-1,8-naphthalimide was obtained by the same method as in Example 1. 10.8 g of the obtained 3-t-butoxycarbonyloxy-N-hydroxy-1,8-naphthalimide was dispersed in 70 g of dichloromethane, and 5.2 g of pyridine was added. Then, while cooling to below 0°C, 13.9 g of trifluoromethanesulfonic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise, and the mixture was stirred for 2 hours. The reaction solution was added to water while maintaining 0°C and washed four times with water. Then, 0.5 g of trifluoromethanesulfonic acid was added dropwise, and the mixture was stirred at room temperature for 1 hour. After filtering off the precipitate from the reaction solution, it was washed with water and dried. This yielded 10 g of 3-hydroxy-1,8-naphthalimide trifluoromethanesulfonate (P-2).

[0112] A solution was prepared by adding 0.209 g of monobutyltin oxide hydrate (BuSnOOH) powder to 10 mL of 4-methyl-2-pentanol. The resulting solution was placed in a closed vial and stirred for 24 hours. The solution was then centrifuged at 4000 rpm for 15 minutes to obtain the supernatant. The supernatant was filtered through a 0.45 μm PTFE syringe filter to remove insoluble materials, and then heated to 600°C to evaporate the solvent and obtain dodecamer butyltin hydroxide oxide.

[0113] An organometallic compound and a photoresist were obtained in the same manner as in Example 1, except that the obtained dodecamer butyltin hydroxide was used as the metal oxide raw material, and (P-2) was used instead of (P-1).

[0114] Example 3 <Synthesis of 3-carboxy-1,8-naphthalimidomethanesulfonate> 2.42 g of 3-carboxy-1,8-naphthalic anhydride was placed in a round-bottom flask and purged with nitrogen. 100 mL of dichloromethane was added and dispersed by stirring, and 2.3 g of EDCI·HCl (manufactured by Tokyo Chemical Industry Co., Ltd.) and 1.47 g of dimethylaminopyridine were added in three equal parts. 0.89 g of tert-butanol was then added, and the reaction mixture was stirred at room temperature for two days. 50 mL of dilute hydrochloric acid was added to stop the reaction, and the mixture was allowed to stand before removing the separated aqueous layer. The organic layer was washed twice more with water, and the concentrated residue was dried in a vacuum dryer to obtain a solid. 3-tert-butoxycarbonyl-1,8-naphthalimidomethanesulfonate was obtained in the same manner as in Example 1, except that the obtained solid was used instead of 3-tert-butoxycarbonyloxy-1,8-naphthalic anhydride, and methanesulfonate was used instead of p-toluenesulfonate. To the obtained 3-tert-butoxycarbonyl-1,8-naphthalimidomethanesulfonate, 28 mL of dichloromethane and 9.7 g of tolfluoroacetic acid were added and the mixture was stirred at room temperature for 2 hours. 60 mL of water was added, and the precipitated solid was dried in a vacuum dryer. This yielded 1.9 g of 3-carboxy-1,8-naphthalimidomethanesulfonate (P-3).

[0115] An organometallic compound and a photoresist were obtained in the same manner as in Example 1, except that (P-3) was used instead of (P-1).

[0116] Example 4 <Synthesis of 3-(1'-carboxypropyl)carbonyloxy-1,8-naphthalimidotrifluoromethanesulfonate> 1.0 g of 3-hydroxy-1,8-naphthalimide trifluoromethanesulfonate, obtained in the same manner as in Example 2, was dispersed in 8.5 g of acetonitrile, and 0.33 g of pyridine was added. The mixture was then heated in an ice bath. 2.3 g of ethylpropanedioic acid dichloride was added to this reaction solution, and the mixture was stirred at 40°C for 6 hours. After cooling to room temperature, the mixture was placed in cold water, and the precipitate was filtered off to obtain a solid. The obtained solid was recrystallized with methanol. This yielded 0.79 g of 3-1'-carboxypropylcarbonyloxy-1,8-naphthalimide trifluoromethanesulfonate (P-4).

[0117] An organometallic compound was obtained and a photoresist was obtained in the same manner as in Example 1, except that zirconium n-propoxide was used as the metal oxide raw material and (P-4) was used instead of (P-1).

[0118] Examples 5-7 Compounds (P-5) to (P-7) listed in the table below were obtained in the same manner as in the above examples, organometallic compounds were obtained, and photoresists were obtained.

[0119] Example 8 <Synthesis of 4-Terephthaloyloxy-1,8-naphthalimidotrifluoromethanesulfonate> 4-hydroxy-1,8-naphthalimide camphor sulfonate was obtained in the same manner as in Example 1, except that 4-hydroxy-1,8-naphthalic anhydride prepared by the method described in Chem.Eur.J.,2016,22(25),8579-8585. was used instead of 3-hydroxy-1,8-naphthalic anhydride, and 10-camphor sulfonate was used instead of p-toluenesulfonate.

[0120] 4-terephthaloyloxy-1,8-naphthalimide camphor sulfonate (P-8) was obtained in the same manner as in Example 4, except that 4-hydroxy-1,8-naphthalimide camphor sulfonate was used instead of 3-hydroxy-1,8-naphthalimide trifluoromethanesulfonate, and phthalic acid dichloride was used instead of ethylpropanedioic acid dichloride.

[0121] An organometallic compound was obtained and a photoresist was obtained in the same manner as in Example 1, except that monobutyltin oxide was used as the metal oxide raw material and (P-8) was used instead of (P-1).

[0122] Examples 9-10 Compounds (P-9) to (P-10) listed in the table below were obtained in the same manner as in the above examples, organometallic compounds were obtained, and photoresists were obtained.

[0123] Example 11 <Synthesis of 4-hydroxy-1,3-dioxoisoindoline-2-ylmethanesulfonate> 0.82 g of 4-hydroxybenzofuran-1,3-dione (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 25 mL of tetrahydrofuran, and 0.12 g of pyridine was added to the solution after it had been heated in an ice bath. Next, 1.2 g of di-t-butyl dicarbonate was added, and the reaction mixture was stirred at 40°C for 3 hours to complete the reaction. The reaction mixture was cooled again with ice, and 0.46 g of hydroxylamine solution was slowly added dropwise. The reaction mixture was then heated to room temperature to complete the reaction, and 75 mL of deionized water was added to stop the reaction. Next, the reaction mixture was filtered, the resulting solid was thoroughly washed with water, and then dried in a vacuum dryer at 40°C. The dried solid was dissolved in 17 mL of dichloromethane, then cooled on ice, and 0.59 g of pyridine was added dropwise. Subsequently, 0.69 g of methanesulfonic acid chloride was added dropwise to the reaction mixture, and the reaction was completed by stirring. Subsequently, 1.54 mL of concentrated hydrochloric acid was slowly added dropwise. The reaction mixture was heated to 40°C to complete the reaction, after which 45 mL of deionized water was added. The precipitated solid was filtered and thoroughly washed with water. This yielded 0.7 g of 4-hydroxy-1,3-dioxoisoindoline-2-ylmethanesulfonate (P-11).

[0124] An organometallic compound was obtained and a photoresist was obtained in the same manner as in Example 1, except that tin chloride was used as the metal oxide raw material and (P-11) was used instead of (P-1).

[0125] Examples 12-14 Compounds (P-12) to (P-14) listed in the table below were obtained in the same manner as in the above examples, organometallic compounds were obtained, and photoresists were obtained.

[0126] Comparative Examples 1-2 0.1 g of a metal or metal oxide listed in the table below, and 0.05 g of a photoacid generator listed in the table below (instead of a complexing agent), were dissolved in 3.0 g of PGMEA. The mixture was then filtered through a 0.20 μm pore size filter to remove undissolved aggregates. A photoresist was obtained.

[0127] The photoresists obtained in the examples and comparative examples were exposed using the method described below. The photosensitivity of the exposed areas and the cleanability of the unexposed areas were then evaluated.

[0128] <Exposure Method> A photoresist was applied to a substrate treated with hexamethyldisilazane using a spin coater, and then the solvent was removed by heating at 80°C for 60 seconds to obtain a coating with a thickness of approximately 50 nm. The obtained coating film was placed in BL-3 of the NewSUBARU Synchrotron Radiation Facility at the University of Hyogo, and irradiated with 13.5 nm synchrotron radiation, with irradiation times varied from 1 to 30 seconds. After that, the coating film was developed by immersing it in butyl acetate for 30 seconds and then dried.

[0129] <Method for evaluating photosensitivity> After development and drying, the exposed areas of the coating film were observed under a microscope, and the minimum exposure dose (Eth) required to achieve a resist film thickness of 40 nm or more in the irradiated area was measured. The ratio of the minimum exposure dose (Eth) to the minimum exposure dose (Eth') when using the photoresist of Comparative Example 1 was calculated using the following formula and used as an indicator of photosensitivity. A smaller minimum exposure dose ratio indicates better photosensitivity. Minimum exposure ratio = Eth / Eth'

[0130] <Method for evaluating developability> After development and drying, the unexposed areas of the coating film were observed under a microscope, and the developability was evaluated according to the following criteria. Evaluation Criteria Good: Development residue is less than 1%. Acceptable: Development residue is between 1% and 10%. Unacceptable: Development residue exceeds 10%

[0131] [Table 1]

[0132] [Table 2]

[0133] [Table 3]

[0134] [Table 4]

[0135] In summary, the configuration of the present invention and its variations are described below. [1] A metal or metal oxide (1) and a compound represented by formula (2a) or (2b) (wherein R 1 -L-(R 2 ) nThe group represented by is a substituent of the aromatic ring shown in the formula, where L represents a single bond or a linking group, and R represents a single bond or a linking group. 2 represents a coordinating group that coordinates to (1) above, and n is an integer of 1 or more. The aromatic ring shown in the formula may have substituents other than the above group) and is an organometallic compound having a structure in which these groups are coordinated. [2] R in the above formula 2 The organometallic compound described in [1], wherein the group is a hydroxyl group, a carboxyl group, a phosphate group, a phosphate monoester group, a sulfonic acid group, a sulfino group, a triazole group, or a tetrazole group. [3] The organometallic compound according to [1] or [2], wherein (1) is at least one selected from hafnium, zirconium, tin, cobalt, palladium, antimony, and oxides thereof. [4] A photosensitive material for photoresists containing an organometallic compound as described in any one of [1] to [3]. [5] The photoresist photosensitive material described in [4], which is a photosensitive material for extreme ultraviolet light or an electron beam. [6] A photoresist comprising an organometallic compound and a solvent as described in any one of [1] to [3].

Claims

1. An organometallic compound having a structure in which a compound represented by the following formula (2a) or (2b) is coordinately bonded to a metal or metal oxide (1), wherein (1) is at least one selected from hafnium, zirconium, tin, cobalt, palladium, antimony, and oxides thereof. 【Chemistry 1】 (In the formula, R １ represents a C1-5 aliphatic hydrocarbon group, a C3-10 alicyclic hydrocarbon group, or a C6-14 aromatic hydrocarbon group, which may have a halogen atom. -L-(R ２ ) ｎ The group represented by is a substituent of the aromatic ring shown in the formula, where L represents a single bond or a linking group, and R represents a single bond or a linking group. ２ (1) represents a coordinating group that coordinates to (1) above, and n is an integer of 1 or more. The linking group is a carbonyl group, an ether bond, a thioether bond, an ester bond, or a divalent group formed by linking these groups with a divalent hydrocarbon group. The coordinating group is a hydroxyl group, a carboxyl group, a phosphate group, a phosphate monoester group, or a sulfonic acid group.

2. A photosensitive material for photoresists comprising the organometallic compound described in claim 1.

3. The photosensitive material for photoresist according to claim 2, which is a photosensitive material for extreme ultraviolet light or an electron beam.

4. A photoresist comprising the organometallic compound and solvent described in claim 1.

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