KR20210082099A - Organically modified metal oxide nanoparticles, organically modified metal oxide nanoparticles-containing solution, organically modified metal oxide nanoparticles-containing resist composition, and resist pattern forming method - Google Patents

Abstract

The present invention relates to organic-modified metal oxide nanoparticles comprising: two or more cores including a plurality of metal atoms and a plurality of oxygen atoms covalently bonded to the plurality of metal atoms; a first modifying group (A1), which is a ligand selected from a group consisting of carboxylate, sulfonic acid, and phosphonic acid, and coordinated to the cores; and a second modifying group (A2) that is coordinated to the cores and at least one selected from a group consisting of the ligand having a structure different from that of the first modifying group (A1) and an inorganic negative ion, wherein the cores have a structure in which at least the first modifying group (A1) is cross-linked by coordination bonds.

Description

Organic-modified metal oxide nanoparticles, organic-modified metal oxide nanoparticles-containing solution, organic-modified metal oxide nanoparticles-containing resist composition and resist pattern formation method NANOPARTICLES-CONTAINING RESIST COMPOSITION, AND RESIST PATTERN FORMING METHOD}

The present invention relates to organically modified metal oxide nanoparticles, a solution containing organically modified metal oxide nanoparticles, a resist composition containing organically modified metal oxide nanoparticles, and a pattern formation method that can be used in photoresist materials used in semiconductor manufacturing processes and the like.

This application claims priority on the basis of Japanese Patent Application No. 2019-233068, filed in Japan on December 24, 2019, and Japanese Patent Application 2020-207558, filed in Japan on December 15, 2020, The content is cited here.

In recent years, thinning of circuit patterns of semiconductors has progressed, and research and development of lithography using extreme ultraviolet light (EUV light) has been accelerated. With the thinning of the pattern, the resist film used for pattern formation becomes thin. For this reason, the resist material provided with the tolerance at the time of etching is calculated|required. As a candidate, a composite material of an inorganic substance such as a metal oxide and an organic substance is being studied.

For example, a method has been proposed in which nanoparticles of an oxide of a metal such as zirconium or hafnium organically modified with an unsaturated carboxylic acid such as methacrylic acid are used as a negative resist material (Patent Document 1 and Patent Document 2) . Since this metal oxide nanoparticle has a metal oxide in the core, the resist material containing this metal oxide nanoparticle has high resistance at the time of etching compared with organic resist material. In addition, since the structure of the metal oxide nanoparticles has high symmetry, there is a low possibility that the metal oxide nanoparticles remain as insolubles on the wafer during development of a resist material containing the metal oxide nanoparticles.

Also, a method has been proposed in which a complex (mononuclear complex or salt) of a metal such as zirconium or hafnium and an organic material represented by carboxylic acid such as methacrylic acid is used as a resist material (Patent Documents 3 to 5). Since this resist material has a small size of the complex itself, it is suitable for thinning compared to a resist material including a nanoparticle core. However, compared with a resist material having nanoparticles as a core, this resist material has a higher proportion of organic matter in the formed film, and therefore has low etching resistance. Further, since the structural symmetry of the complex is low, there is a high possibility that the complex remains as an insoluble material on the wafer during development of a resist material containing the complex.

Japanese Laid-Open Patent Publication No. 2017-173537 Japanese Laid-Open Patent Publication No. 2015-157807 Japanese Laid-Open Patent Publication No. 2015-108781 Japanese Patent Laid-Open No. 2012-185484 Japanese Patent Laid-Open No. 2001-72716

Based on the above, the synthesis of organically modified metal oxide nanoparticles with the core diameter controlled as small as possible becomes important for the development of a resist material for forming a thin wire pattern. However, regarding the reaction mechanism during EUV exposure of the resist material, it has been found that decarboxylation proceeds when unsaturated carboxylic acid is used. However, the detailed mechanism and important factors in the exposure operation that determine the resolution and sensitivity are always clarified. However, there is a demand for establishing a method for controlling resolution and sensitivity using a resist material.

Adjustment of sensitivity and resolution is often performed by optimizing the solvent and additive of a resist solution or a developing solution. However, by controlling the structure of the organically modified metal oxide nanoparticles themselves, more specifically, by modifying with a plurality of modifying groups having different structures in addition to the elements and structures constituting the metal oxide as the core and controlling the composition thereof, the resist If it is possible to achieve adjustment of the sensitivity and resolution of the material, it becomes possible to examine more various methods of adjusting the resist material.

The present invention has been made in view of the above circumstances, and can be manufactured by a simple method and can increase the resolution and sensitivity of a resist material. Organic modified metal oxide nanoparticles, organic modified metal oxide nanoparticles containing solution, and organic modification An object of the present invention is to provide a resist composition containing metal oxide nanoparticles and a method for forming a resist pattern.

The organic-modified metal oxide nanoparticles according to the first aspect of the present invention include two or more cores comprising a plurality of metal atoms and a plurality of oxygen atoms covalently bonded to the plurality of metal atoms, and the core is coordinated, A first modifying group (A1), which is a ligand selected from the group consisting of carboxylate carboxylate, sulfonic acid sulfonate, and phosphonic acid phosphonate, and a ligand that is coordinately bonded to the core and has a different structure from the first modifying group and a second modifying group (A2) which is at least one selected from the group consisting of an inorganic anion, and has a structure in which the cores are crosslinked by coordination bonds by at least the first modifying group (A1).

The organo-modified metal oxide nanoparticle-containing solution according to the second aspect of the present invention contains the organo-modified metal oxide nanoparticles according to the above aspect and a solvent.

The organic-modified metal oxide nanoparticle-containing resist composition according to the third aspect of the present invention contains the organically modified metal oxide nanoparticles of the above aspect, a solvent, and may further contain an additive. In addition, the number of metal atoms contained in one core of the organically modified metal oxide nanoparticles is preferably in the range of 2 to 12.

A method for forming a resist pattern according to a fourth aspect of the present invention comprises the steps of: forming a resist film on a support using the organic modified metal oxide nanoparticle-containing resist composition according to the above aspect; and exposing the resist film; and developing the resist film after exposure to form a resist pattern.

According to the present invention, organic modified metal oxide nanoparticles, organic modified metal oxide nanoparticle-containing solution, and organically modified metal oxide nanoparticle-containing resist composition, which can be produced by a simple method and can be adapted to resist materials with high resolution and sensitivity this is provided Moreover, according to this invention, the resist pattern formation method which can aim at thinning of a mask is provided.

When the resist material is irradiated with EUV light, the reactivity, that is, the sensitivity, and the resolution of the formed resist pattern of the organic-modified metal oxide nanoparticles composed of a ligand such as a metal oxide and a carboxylic acid contained in the resist material are nanoscale. It differs greatly depending on the structural element and structure of a particle|grain core, and the kind, structural element, size, and molecular weight of ligands, such as carboxylic acid to coordinate. In order to disperse the nanoparticle resist material well in the solvent when adjusting the resist solution, a carboxylic acid having a high affinity with the solvent, that is, having a structure necessary for maintaining the affinity, etc. is required as the first ligand. do. On the other hand, considering that decarboxylation of the carboxyl group of carboxylic acid proceeds when irradiated with EUV light after film formation, it is better to make the distance between the particles in the film after film formation as narrow as possible due to particle aggregation when irradiated with EUV light. Since the expansion of the distribution of the microstructure, that is, the decrease in resolution, can be avoided, for example, a carboxylic acid having a structure different from that of the first ligand is used as a second ligand in order to narrow the distance between particles, such as a small molecular size. is required as

(Solution containing organic modified metal oxide nanoparticles)

The present inventors have found that by coordinating ligands with different structures to the core of a metal oxide, while maintaining the solubility of the organically modified metal oxide nanoparticles obtained in a resist solvent and a developer, EUV is applied to a resist material containing the organically modified metal oxide nanoparticles. It was found that, while maintaining high resolution when irradiated with light, the high sensitivity of the resist film to EUV light, in other words, the low solubility in the developing solution of the EUV irradiated portion after EUV light irradiation.

The organic-modified metal oxide nanoparticles according to the embodiment of the present invention include two or more cores, a first modifying group (A1), and a second modifying group (A2). The core has a plurality of metal atoms and a plurality of oxygen atoms covalently bonded to the plurality of metal atoms. That is, the core contains a metal oxide. The core includes, in addition to the metal oxide crystal, a cluster of a structure in which a plurality of metal atoms are covalently crosslinked with a plurality of oxygen atoms, and/or a structure in which the cluster is coordinated with a cluster of another core by an organic ligand can do. That is, the "core" of the present embodiment has a structure in which at least a part is constituted by clusters, and/or a structure in which a plurality of cores including clusters at least in part have a structure in which a plurality of cores are coordinated by a plurality of organic ligands. may include. Metal oxide crystals and metal oxide clusters are common in that they are combinations of metal atoms and oxygen atoms, but in metal oxide crystals, individual particles are themselves three-dimensionally arranged in a regular manner and have a certain size (e.g., metal atoms and oxygen atoms). For example, 3 nm to 4 nm) and forming a crystal structure, on the other hand, a metal oxide cluster is different in that individual particles are molecules having a metal complex structure and individual particles themselves do not have a crystal structure. A plurality of metal atoms may be constituted by the same kind or may be constituted by different kinds. The first modifying group (A1) is a ligand selected from the group consisting of carboxylic acid carboxylate, sulfonic acid sulfonate and phosphonic acid phosphonate coordinated to the core. Carboxylic acid carboxylate is a carboxylate. Sulfonic acid sulfonate is a sulfonate. The phosphonate phosphonate is a phosphonate. The second modifying group (A2) is at least one selected from the group consisting of a ligand and an inorganic anion that are coordinated to the core and have a structure different from that of the first modifying group (A1). The cores have a structure crosslinked by coordination bonds by at least the first modifying group (A1). The "structure crosslinked by coordination bonds with at least the first modifying group (A1)" means a structure in which two cores are crosslinked by coordination bonds with the first modifying group (A1), and the two cores are crosslinked by a first number It means to include one or both of the structures crosslinked by coordination bonds by the tableware (A1) and the second modifying group (A2). The two cores may include a first modifying group (A1) that is not crosslinked and/or a second modifying group (A2) that is not crosslinked on the premise that the above-mentioned crosslinked structure is included.

The first modifying group (A1) can be a ligand derived from a compound selected from the group consisting of the following general formula (a01), the following general formula (a02) and the following general formula (a03).

[Formula 1]

[Formula 2]

[Formula 3]

[wherein, R is each independently an alkyl group having 1 to 18 carbon atoms, an alkoxyalkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkenyloxyalkyl group having 1 to 18 carbon atoms, and an alkyl group having 1 to 18 carbon atoms. a group selected from a nyl group, an alkynyloxyalkyl group having 1 to 18 carbon atoms, an aryl group having 1 to 18 carbon atoms, an aryloxyalkyl group having 1 to 18 carbon atoms, and a cyanoalkyl group having 1 to 18 carbon atoms, or 1 or 2 of the above groups It is a group in which two or more hydrogen atoms are substituted with a substituent. However, the substituent does not include a carboxy group, a carboxylate group, a sulfo group, a sulfonate group, a phospho group, and a phosphonate group.]

In said R, a C1-C18 alkyl group, a C1-C18 alkoxyalkyl group, a C1-C18 alkenyl group, a C1-C18 alkenyloxyalkyl group, a C1-C18 alkynyl group, a C1-C18 The alkyl group, alkenyl group, and alkynyl group in the alkynyloxyalkyl group, aryloxyalkyl group having 1 to 18 carbon atoms or cyanoalkyl group having 1 to 18 carbon atoms of Although it may contain, a linear or branched type is preferable. When the alkyl group having 1 to 18 carbon atoms is linear, the alkyl group preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms. . When the alkyl group having 1 to 18 carbon atoms is branched, the alkyl group preferably has 3 to 18 carbon atoms, more preferably 3 to 12 carbon atoms, still more preferably 3 to 10 carbon atoms, particularly preferably 3 to 6 carbon atoms. . C3-C18 is preferable, as for the said C1-C18 alkoxyalkyl group, C3-C12 is more preferable, C3-C10 is still more preferable, C3-C6 is especially preferable. C2-C15 is preferable, as for the said C1-C18 alkenyl group, C2-C10 is more preferable, C2-C6 is still more preferable, C2-C4 is especially preferable. The alkenyloxyalkyl group having 1 to 18 carbon atoms has preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms, still more preferably 3 to 6 carbon atoms, and particularly preferably 3 to 5 carbon atoms. The alkynyl group having 1 to 18 carbon atoms preferably has 2 to 15 carbon atoms, more preferably 2 to 10 carbon atoms, still more preferably 2 to 6 carbon atoms, and particularly preferably 2 to 4 carbon atoms. The alkynyloxyalkyl group having 1 to 18 carbon atoms has preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms, still more preferably 3 to 6 carbon atoms, and particularly preferably 3 to 5 carbon atoms. The aryl group having 1 to 18 carbon atoms has preferably 6 to 15 carbon atoms, more preferably 6 to 12 carbon atoms, still more preferably 6 to 10 carbon atoms, and particularly preferably 6 to 8 carbon atoms. The aryloxyalkyl group having 1 to 18 carbon atoms has preferably 6 to 15 carbon atoms, more preferably 6 to 12 carbon atoms, still more preferably 6 to 10 carbon atoms, and particularly preferably 6 to 8 carbon atoms. The cyanoalkyl group having 1 to 18 carbon atoms has preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms. The said C1-C18 alkyl group, a C1-C18 alkoxyalkyl group, a C1-C18 alkenyl group, a C1-C18 alkenyloxyalkyl group, a C1-C18 alkynyl group, a C1-C18 alkynyloxy group. In an alkyl group, a C1-C18 aryl group, a C1-C18 aryloxyalkyl group, or a C1-C18 cyanoalkyl group, the substituent which may substitute a hydrogen atom is not specifically limited, For example, an amino group, A hydroxyl group, a cyano group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) etc. are mentioned, However, It is not limited to these. However, the said substituent does not contain a carboxy group, a carboxylate group, a sulfo group, a sulfonate group, a phospho group, and a phosphonate group.

The compound represented by the formula (a01) is, when coordinated to the core, -C (= O) O and H are released from -C (= O) OH in the formula ^- is a. Therefore, the first number of dishes (A1) derived from a compound represented by the above general formula (a01), the formula "RC (= O) O ^- 'can be represented by.

A compound represented by the above general formula (a02) is, when coordinated to the _{core, -S (= O 2) -S} (= O 2) O and H is released from the OH in the formula ^- is a. Accordingly, the first modifying group (A1) derived from the compound represented by the general formula (a02) can be represented by the formula “RS(=O ₂ )O ⁻ ”.

A compound represented by the above general formula (a03) is, when coordinated to the core, the expression of the H is released from -P (= O) (OH) 2 -P (= O) (OH) O - or -P ( =O)(O ^- ) ₂ . Therefore, the first number of dishes (A1) derived from a compound represented by the above general formula (a03), the expression "RP (= O) (OH) O - " ^- with or _{"2 RP (= O) (O} ) ." can indicate

The first modifying group (A1) is preferably a carboxylic acid carboxylate ligand, more preferably a ligand derived from a saturated carboxylic acid, and particularly preferably a ligand derived from propionic acid or methacrylic acid. Single 1 type may be sufficient as 1st modifying group (A1), and 2 or more types may be sufficient as it.

When the first modifying group (A1) is a carboxylic acid carboxylate ligand, the second modifying group (A2) is a carboxylic acid carboxylate, sulfonic acid sulfonate, or phosphonate having a structure different from that of the first modifying group (A1). It is preferably a ligand selected from the group consisting of phosphonate phosphonate, a hydroxyl group-containing ligand, a thiol group-containing ligand, an amino group-containing ligand, a nitrate ligand (nitrate ion) and a hydroxide ion, and has a structure with the first modifying group (A1) It is more preferably a ligand selected from the group consisting of carboxylic acid carboxylates and sulfonic acid sulfonates different from each other, and particularly preferably a carboxylic acid carboxylate having a structure different from that of the first modifying group (A1). Single 1 type may be sufficient as 2nd modifier (A2), and 2 or more types may be sufficient as it. When the 2nd modifying group (A2) is or 2 or more types, at least 1 type selected from the group which consists of a hydroxide ion and a hydroxyl group, and the carboxylic acid carboxylate and sulfonic acid different in structure from the 1st modifying group (A1) It is preferable that it is at least 1 sort(s) chosen from the group which consists of a sulfonate, and it is more preferable that it is a carboxylate carboxylate and hydroxide ion from which a structure differs from a 1st modifying group (A1).

Examples of the carboxylic acid carboxylate ligand include ligands derived from acetic acid, propionic acid, butyric acid, isobutyric acid, methacrylic acid, valeric acid, and caproic acid.

Examples of the sulfonic acid sulfonate ligand include ligands derived from methylsulfonic acid, trifluoromethanesulfonic acid, and p-toluenesulfonic acid.

As a phosphonate phosphonate ligand, the ligand derived from methylphosphonic acid, phenylphosphonic acid, etc. is mentioned, for example.

Examples of the thiol group-containing ligand include ligands derived from butylthiol, benzothiol, trifluoromethylbenzothiol and the like.

Examples of the amino group-containing ligand include ligands derived from hexylamine, aniline, and the like.

When the second modifying group (A2) is a ligand having a structure different from that of the first modifying group (A1), it may be a ligand selected from the group consisting of carboxylic acid carboxylate, sulfonic acid sulfonate and phosphonic acid phosphonate, , each of the above-described ligands exemplified as the first modifier (A1) can be applied.

When the second modifying group (A2) is an inorganic anion, examples of the inorganic anion include a nitrate ligand (nitrate ion) and a hydroxide ion.

When a 2nd modifying group (A2) is a ligand and inorganic anion from which a structure differs from a 1st modifying group (A1), an acetate carboxylate ligand and a hydroxide ion are mentioned, for example.

Specifically, the organically modified metal oxide nanoparticles of the present embodiment are preferably represented by the following formula (m01).

C01-L01-C02 ... (m01)

In the above formula (m01),

C01 is M ₆ O ₄ (OH) ₄ [X _a Y _b ], and 0 ≤ a ≤ 10 and 1 ≤ b ≤ 11 . C02 is M ₆ O ₄ (OH) ₄ [X _c Y _d ], and 0 ≤ c ≤ 10 and 1 ≤ d ≤ 11 . L01 is Xw, w = 24 - (a + b + c + d), 2 ≤ w ≤ 12.

M is the said metal atom, and is a metal atom of a group 4 element. X is a first modifier (A1), and Y is a second modifier (A2).

In the above formula (m01), the number of ligands in each of the first modifying groups (A1) of C01 and C02 located on both sides with L01 as the center may be the same (a = c) or different (a ≠ c). The number of ligands in each of the second modifying groups (A2) of C01 and C02 may be the same (b = d) or different (b ≠ d).

The number of ligands in the first modifying group (A1) that bridges C01 and C02 is preferably 2 or more and 8 or less (2 ≤ w ≤ 8), and more preferably 2 or more and 4 or less (2 ≤ w ≤ 4).

It is preferable that it is 1 or more types chosen from Zr, Hf, and Ti, and, as for the metal atom of the said Group 4 element, it is more preferable that it is Zr.

The first modifying group (A1) represented by X is preferably a carboxylate, more preferably a ligand derived from propionic acid or methacrylic acid, and still more preferably a ligand derived from propionic acid.

The second modifying group (A2) represented by Y is preferably a carboxylate different from that of X, more preferably a ligand derived from propionic acid or methacrylic acid, furthermore a ligand derived from methacrylic acid desirable.

As a combination of X and Y, for example, a combination in which X is a ligand derived from methacrylic acid, Y is a ligand derived from propionic acid, X is a ligand derived from propionic acid, and Y is a ligand derived from methacrylic acid. combinations that are ligands; and the like. The combination of X and Y is preferably a combination in which X is a ligand derived from propionic acid and Y is a ligand derived from methacrylic acid.

In the formula (m01), OH functions as the second modifying group (A2). That is, the organic-modified metal oxide nanoparticles represented by the formula (m01) contain Y and OH as the second modifying group (A2).

a and c are each independently preferably 1 or more and 9 or less (1 ≤ a ≤ 9, 1 ≤ c ≤ 9), more preferably 2 or more and 8 or less (2 ≤ a ≤ 8, 2 ≤ c ≤ 8) ), more preferably 3 or more and 7 or less (3 ≤ a ≤ 7, 3 ≤ c ≤ 7). b and d are each independently preferably 2 or more and 10 or less (2 ≤ b ≤ 10, 2 ≤ d ≤ 10), more preferably 2 or more and 8 or less (2 ≤ b ≤ 8, 2 ≤ d ≤ 8) ), more preferably 3 or more and 7 or less (3 ≤ b ≤ 7, 3 ≤ d ≤ 7).

Specific examples of the organo-modified metal oxide nanoparticles represented by the formula (m01) include organo-modified metal oxide nanoparticles (m01-1) in which C01, C02 and L01 in the formula (m01) are respectively as follows, It is not limited to this.

C01 = Zr ₆ O ₄ (OH) ₄ (C ₃ H ₅ O ₂ ) _1.96 (C ₄ H ₅ O ₂ ) _8.04

C02 = Zr ₆ O ₄ (OH) ₄ (C ₃ H ₅ O ₂ ) _1.96 (C ₄ H ₅ O ₂ ) _8.04

L01 = (C ₃ H ₅ O ₂ ) ₄

In addition, in the said organic-modified metal oxide nanoparticle (m01-1), in formula (m01), M = Zr, X = C ₃ H ₅ O ₂ , Y = C ₄ H ₅ O ₂ , a = 1.96, b = 8.04, c = 1.96, d = 8.04, w = 4.

(Solution containing organic modified metal oxide nanoparticles)

The organic-modified metal oxide nanoparticle-containing solution according to an embodiment of the present invention contains the organically-modified metal oxide nanoparticles of the above-described embodiment and a solvent.

As a solvent of the said solution, Lactones, such as (gamma)-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; A compound having an ester bond, such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, monomethyl ether, monoethyl ether of the polyhydric alcohol or compound having an ester bond, Derivatives of polyhydric alcohols such as monoalkyl ethers such as monopropyl ether and monobutyl ether, or compounds having ether bonds such as monophenyl ether [among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) is preferable]; cyclic ethers such as dioxane, esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; Anisole, ethylbenzyl ether, crezyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene Aromatic organic solvents, such as dimethyl sulfoxide (DMSO), etc. are mentioned. The solvent may be a mixed solvent containing the above organic solvent as a main component and containing a small amount of water.

Since the organic-modified metal oxide nanoparticles are easily soluble in propylene glycol 1-monomethyl ether 2-acetate (PGMEA), which is one of the general-purpose resist solvents, it is preferable to use PGMEA as a solvent for the solution.

Further, as a metal oxide cluster, as shown by the above formula (m01), two structures of M ₆ O ₄ (OH) ₄ are not crosslinked in addition to the particles (dimer) crosslinked by the coordination bond of the ligand. A monomer of M ₆ O ₄ (OH) ₄ [X _a Y _b ], with the proviso that 0 ≤ a ≤ 10 and 1 ≤ b ≤ 11 may also be taken. Judging only from the viewpoint of the particle size, it is easy to judge that the monomer is superior in forming a thin wire. However, in actual resist applications, sensitivity is very important. In general, when the dissolution rate of the EUV unirradiated portion is too fast, it tends to be difficult to make the irradiated portion poorly soluble. Smaller particles are superior not only in resolution but also in terms of dissolution rate, but on the other hand, when too small, the dissolution rate is too fast, and even if the irradiation amount is increased, poorly soluble and the sensitivity is deteriorated. Therefore, control of the appropriate dissolution rate is also important, and the organic modified metal oxide nanoparticles are preferably a dimer or a mixture of a dimer and a monomer.

(Resist composition containing organic modified metal oxide nanoparticles)

The organic-modified metal oxide nanoparticle-containing resist composition according to an embodiment of the present invention contains the organically modified metal oxide nanoparticles of the above-described embodiment and a solvent.

Examples of the solvent for the resist composition 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; A compound having an ester bond, such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, monomethyl ether, monoethyl ether of the polyhydric alcohol or compound having an ester bond, Derivatives of polyhydric alcohols such as monoalkyl ethers such as monopropyl ether and monobutyl ether, or compounds having ether bonds such as monophenyl ether [among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) is preferable]; cyclic ethers such as dioxane, esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; Anisole, ethylbenzyl ether, crezyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene Aromatic organic solvents, such as dimethyl sulfoxide (DMSO), etc. are mentioned. The solvent may be a mixed solvent containing the above organic solvent as a main component and containing a small amount of water.

Since the organic-modified metal oxide nanoparticles are easily soluble in propylene glycol 1-monomethyl ether 2-acetate (PGMEA), which is one of the general-purpose resist solvents, it is preferable to use PGMEA as a solvent for the resist composition.

The resist composition may contain an additive. Examples of the additive include dispersants and stabilizers such as organic carboxylic acids and compounds selected from the group consisting of phosphorus oxo acids and derivatives thereof, photoresponders such as acid generators, crosslinking accelerators, surfactants, base components, and fluorine additives. ingredients, and the like. The organic-modified metal oxide nanoparticle-containing resist composition may contain two or more kinds of the above additives. Even when an additive is added to a solvent containing organic-modified metal oxide nanoparticles, high resolution can be maintained when irradiated with EUV light while maintaining solubility of organic-modified metal oxide nanoparticles in a solvent, and the resist film against EUV light High sensitivity can be expressed.

The acid generator is a substance that generates an acid upon exposure by the action of exposure light or the like. As such an acid generator, Onium salt-type acid generators, such as an iodonium salt and a sulfonium salt, an oxime sulfonate-type acid generator; diazomethane-based acid generators such as bisalkyl or bisarylsulfonyldiazomethanes and poly(bissulfonyl)diazomethanes; and various kinds of nitrobenzylsulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators.

A crosslinking accelerator is a compound which generates an acid or a base by light or heat. By further containing a crosslinking accelerator, resist pattern formability and etching selectivity can be improved. As a crosslinking accelerator, an onium salt compound, N-sulfonyloxyimide compound, etc. are mentioned, for example.

Surfactant is a component which shows the effect|action which improves applicability|paintability, striation, etc. As the surfactant, for example, an ionic or nonionic fluorine-based and/or silicone-based surfactant can be used.

A base component is a compound which traps (ie, controls the diffusion of an acid) an acid generated by exposure. Examples of the base component include photodegradable bases and nitrogen-containing organic compounds that are decomposed by exposure and lose acid diffusion controllability.

The fluorine additive component is a compound for imparting water repellency to the resist film or for improving lithography properties. (F) As a component, Unexamined-Japanese-Patent No. 2010-002870, Unexamined-Japanese-Patent No. 2010-032994, Unexamined-Japanese-Patent No. 2010-277043, Unexamined-Japanese-Patent No. 2011-13569, Unexamined-Japanese-Patent No. The fluorinated polymer compound described in Publication No. 2011-128226 can be used.

A method for producing organically modified metal oxide nanoparticles according to an embodiment of the present invention comprises reacting a metal oxyacetic acid and/or a metal alkoxide with an acid selected from the group consisting of carboxylic acid, sulfonic acid and phosphonic acid in a liquid. It has a reaction process. As a liquid, water, methanol, ethanol, a propanol, a butanol, acetone, etc. are mentioned.

An example of a method for producing organically modified metal oxide nanoparticles using a metal alkoxide is described. A solution of a metal alkoxide is added to two types of carboxylic acids having different structures, stirred as needed, and the resulting precipitate is washed multiple times with alcohol, separated by filtration, and dried. In this way, the organic-modified metal oxide nanoparticles of the present embodiment are obtained by a simple method. Moreover, it is preferable that it is 1 or more types of a zirconium alkoxide, a hafnium alkoxide, and a titanium alkoxide, and, as for a metal alkoxide, it is more preferable that it is a zirconium alkoxide.

The organic-modified metal oxide nanoparticle-containing resist composition according to an embodiment of the present invention can be prepared by filtering the organically modified metal oxide nanoparticle-containing solution through a membrane filter having a pore diameter of about 0.1 µm.

The organic-modified metal oxide nanoparticle-containing resist composition according to the embodiment of the present invention may be dissolved in a solvent component, and then impurities may be removed using a porous polyimide film, a porous polyamideimide film, or the like. . For example, the resist composition may be filtered using a filter made of a porous polyimide film, a filter made of a porous polyamideimide film, a filter made of a porous polyimide film and a porous polyamideimide film, or the like. As said polyimide porous membrane and said polyamideimide porous membrane, the thing of Unexamined-Japanese-Patent No. 2016-155121 etc. are illustrated, for example.

A pattern forming method according to an embodiment of the present invention includes a film forming step, an exposure step, and a resist pattern forming step. In the film forming step, a resist film is formed on the support using the organic modified metal oxide nanoparticle-containing solution of the present embodiment or the organic modified metal oxide nanoparticle-containing resist composition of the present embodiment. For example, on the etching target layer, the said solution or the said resist composition is apply|coated, and it is made to dry and a resist film is obtained. The type of the etching target layer is not particularly limited. It does not specifically limit as an etching target layer, A conventionally well-known thing can be used, For example, the board|substrate for electronic components, the thing in which the predetermined wiring pattern was formed, etc. are mentioned. More specifically, a silicon wafer, a metal substrate, such as copper, chromium, iron, and aluminum, a glass substrate, etc. are mentioned.

Moreover, as a support body, the thing in which the film|membrane of the inorganic type and/or organic type was formed on the above-mentioned board|substrate may be sufficient. Examples of the inorganic film include an inorganic antireflection film (inorganic BARC). Examples of the organic film include an organic antireflection film (organic BARC) and an organic film such as a lower organic film in a multilayer resist method.

In the exposure step, the resist film is exposed. For example, EUV light is irradiated to the resist film in a predetermined pattern. In the developing step, the resist film after exposure is developed to form a resist pattern. For example, a resist film is immersed in a developing solution, such as butyl acetate, and the part which has not been irradiated with EUV light is melted and removed in a developing solution, and an etching opening part is formed. By using the organic-modified metal oxide nanoparticle-containing solution of the present embodiment or the organic-modified metal oxide nanoparticle-containing resist composition of the present embodiment, the line width of the etching mask can be, for example, 20 nm or less. For this reason, thinning of a mask can be achieved, and fine etching of an etching target layer becomes possible.

In the resist pattern forming step, the resist film exposed in the exposure step is developed to form a resist pattern. As a developing solution used for this image development, the developing solution containing aqueous alkali solution, an organic solvent, etc. are mentioned.

Examples of the aqueous alkali solution include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldi Ethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, 1,5 and an alkaline aqueous solution in which at least one of alkaline compounds such as -diazabicyclo-[4.3.0]-5-nonene is dissolved.

As an organic solvent in the developing solution containing an organic solvent, the thing similar to the organic solvent illustrated in the solvent, etc. are mentioned, for example. Among these, those containing an alcohol solvent, an amide solvent, an ester solvent, an ether solvent, a ketone solvent, a hydrocarbon solvent, or a combination thereof are preferable, and butyl acetate is particularly preferable.

You may use these developing solutions individually by 1 type or in combination of 2 or more type. In addition, it is common to dry after washing|cleaning with water etc. after image development.

Example

Hereinafter, an embodiment of the present invention will be described. The present invention is not limited only to the following examples.

(Example 1)

2.47 ml of propionic acid and 2.78 ml of methacrylic acid were respectively added to the container, and mixed so as to be uniform. 4.5 ml of an 80 wt% zirconium butoxide 1-butanol solution was slowly added there. After sealing, stirring was continued at room temperature until a precipitate was formed (1 - 20 days). The resulting precipitate was washed 5 times with a minimum amount of n-butanol (3 mL) and dried in vacuo. This was grind|pulverized and the white solid was obtained. From the result of analyzing this white powder by NMR (manufactured by Bruker, equipment name "AVANCE III 400"), the substance amount ratio (so-called mol ratio) of the ligand contained in the powder was found to be propionic acid: methacrylic acid = 33: 67 = 3.96: 8.04 was able to confirm that From the analysis result of TG-TDA (the HITACHI company make, apparatus name "STA-7200"), the weight reduction rate was 54.3 %. In addition, as a result of IR analysis of this white powder (manufactured by Thermo Scientific, device name "NICOLET 6700"), absorption peaks (1550 cm ^-1 and 1420 cm ^-1 ) derived from carboxyl groups were confirmed.

In 5.0 g of PGMEA, 0.15 g of this white powder was dissolved. Using centrifugation and a filter with a pore diameter of 0.2 mu m, undissolved white powder was removed. As a result of dynamic light scattering analysis of the solution after this removal (manufactured by Malvern, device name "Zetasizer Nano S"), the volume-based average particle diameter of this white powder was about 3 nm. From this result, the obtained white powder was an organic-modified metal oxide nanoparticle in which propionic acid and methacrylic acid were coordinated with respect to the core which consists of zirconium and oxygen.

Since the particle diameter value of about 3 nm obtained from the result of the dynamic light scattering analysis is the diameter of the dispersion containing the surrounding ligands, at least a part of the core was not a metal oxide crystal, but a cluster in which zirconium atoms were crosslinked with oxygen atoms. From the result of single crystal X-ray structural analysis (manufactured by RIGAKU, device name "XtaLAB P200"), the cluster is composed of two cores having a composition _{of Zr 6} O ₄ (OH) _{4 in which six zirconium atoms are covalently crosslinked with oxygen atoms.} It was confirmed that the structure had a cross-linked structure by the coordination bond of propionic acid. The ratio of post-analysis from the results of TG-TDA residue (ZrO ₂₎ was 45.7%. Based on the above results, the white powder has a ZrO ₂ conversion content of 44.7%, and is [Zr ₆ O ₄ (OH) ₄ (C ₄ H ₅ O ₂ ) _8.04 (C ₃ H ₅ O ₂ ) _3.96 ] ₂ . could check When this corresponds to the above formula (m01), C01, C02, and L01 respectively become as follows.

C01 = Zr ₆ O ₄ (OH) ₄ (C ₃ H ₅ O ₂ ) _1.96 (C ₄ H ₅ O ₂ ) _8.04

C02 = Zr ₆ O ₄ (OH) ₄ (C ₃ H ₅ O ₂ ) _1.96 (C ₄ H ₅ O ₂ ) _8.04

L01 = (C ₃ H ₅ O ₂ ) ₄

In addition, M, X, Y, a, b, c, d and w in the formula (m01) are, respectively, M = Zr, X = C ₃ H ₅ O ₂ , Y = C ₄ H ₅ O ₂ , a = 1.96, b = 8.04, c = 1.96, d = 8.04, w = 4.

(Comparative Example 1)

In a glove box, 1.02 g of methacrylic acid was added to 1.40 g of an 85% zirconium butoxide 1-butanol solution, stirred, and it was made to stand still for about 3 weeks, and the transparent crystal|crystallization was obtained. From the results of single crystal X-ray structural analysis (manufactured by RIGAKU, device name “XtaLAB Synergy-S”), the cluster is one core having a composition _{of Zr 6} O ₄ (OH) _{4 in which six zirconiums are covalently crosslinked with oxygen. and Zr 6} O ₄ (OH) ₄ (C ₄ H ₅ O ₂ ) ₁₂ in which 12 methacrylic acids are crosslinked by coordination bonds around one core. These transparent crystals were recovered by filtration under reduced pressure, vacuum dried at room temperature for 1 day, and pulverized to obtain a white powder. As a result of elemental analysis of this white powder, the carbon content was 36 wt%. As a result of thermogravimetric analysis of this white powder, the weight reduction rate was 57%.

In addition, as a result of IR analysis of this white powder (manufactured by Thermo Fischer Scientific, device name "NICOLET 6700"), the absorption peak derived from the carboxyl group of methacrylic acid (1558 cm ^-1 ) and the expansion and contraction band of C = C The absorption peak (1647 cm ^{-1 ) and the absorption peak (827 cm -1} ) of the out-of-plane angle vibration band of the vinyl group CH were confirmed. Further, as a result of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS) (manufactured by Bruker, device name "autoflex speed") of this white powder, m/z 1702 was present, and methacrylic acid was coordinated. It was consistent with the zirconia hexamer molecular weight. From the above, the obtained white powder was Zr ₆ O ₄ (OH) ₄ (C ₄ H ₅ O ₂ ) ₁₂ .

In 3.0 g of PGMEA, 0.09 g of this white powder was dissolved. Using centrifugation and a filter having a pore diameter of 0.45 µm, undissolved white powder was removed. As a result of dynamic light scattering analysis of the solution after this removal, the volume-based average particle diameter of this white powder was about 2 nm. From this result, the obtained white powder was an organic-modified metal oxide nanoparticle in which methacrylic acid coordinated with respect to the core comprised from zirconium and oxygen.

(Formation of resist pattern)

Using the PGMEA solution of the organic modified metal oxide nanoparticles prepared in Example 1 as the resist composition of Example 1 and the PGMEA solution of the organic modified metal oxide nanoparticles prepared in Comparative Example 1 as the resist composition of Comparative Example 1, a resist pattern was formed formed.

Each resist composition of Example 1 and Comparative Example 1 was dripped on a silicon wafer, it rotated at 1500 rpm for 60 second, and it formed into a film, After that, it heated at 80 degreeC for 60 second, and obtained the resist film. After EUV exposure of this resist film at an irradiation dose of 0 to 25 mJ/cm 2 (manufactured by Lisotech Japan, device name “EUV frame exposure device EUVES-7000GC”), it was developed by immersion in butyl acetate for 30 seconds, followed by drying and spectroscopy ellipsometer. The film thickness was measured with the meter (the Horiba Jobin Ebon company make, apparatus name "UVISEL"), and the sensitivity was calculated|required.

As can be seen from the results in Table 1, it was confirmed that the resist composition of Example 1 was superior in sensitivity to that of Comparative Example 1.

The organic-modified metal oxide nano-particle-containing resist solution, the organic-modified metal oxide nano-particle-containing resist composition, and the pattern forming method of the present invention have excellent sensitivity, so they are preferable for the manufacture of semiconductor devices that are expected to be further miniaturized in the future. can be used

In the above, preferred embodiments of the present invention have been described, but the present invention is not limited to these examples. In the range which does not deviate from the meaning of this invention, addition, omission, substitution, and other changes of a structure are possible. The present invention is not limited by the foregoing description, but only by the scope of the appended claims.

Claims (9)

Two or more cores comprising a plurality of metal atoms and a plurality of oxygen atoms covalently bonded to the plurality of metal atoms;
A first modifying group (A1), which is a ligand selected from the group consisting of carboxylate, sulfonic acid, and phosphonate phosphonate, coordinated to the core;
having a second modifying group (A2) which is at least one selected from the group consisting of a ligand and an inorganic anion that is coordinated to the core and has a structure different from that of the first modifying group (A1);
The organic-modified metal oxide nanoparticles having a structure in which the cores are crosslinked by coordination bonds by at least the first modifying group (A1). The method of claim 1,
The organic-modified metal oxide nanoparticles, wherein the first modifying group (A1) is a ligand derived from a compound selected from the group consisting of the following general formula (a01), the following general formula (a02) and the following general formula (a03).

[In the general formulas (a01), (a02), and (a03), R is each independently an alkyl group having 1 to 18 carbon atoms, an alkoxyalkyl group having 1 to 18 carbon atoms, or an alkoxyalkyl group having 1 to 18 carbon atoms An alkenyl group, a C1-C18 alkenyloxyalkyl group, a C1-C18 alkynyl group, a C1-C18 alkynyloxyalkyl group, a C1-C18 aryl group, a C1-C18 aryloxyalkyl group, and a C1 to 18, a group selected from the group consisting of a cyanoalkyl group, or a group in which one or two or more hydrogen atoms of the group are substituted with a substituent. However, the substituent does not include a carboxy group, a carboxylate group, a sulfo group, a sulfonate group, a phospho group, and a phosphonate group.] The method of claim 1,
The organic-modified metal oxide nanoparticles, wherein the first modifying group (A1) is a carboxylate ligand. The method of claim 1,
The first modifying group (A1) is a carboxylic acid carboxylate ligand,
The second modifying group (A2) is a carboxylic acid carboxylate, sulfonic acid sulfonate, phosphonic acid phosphonate, hydroxyl group-containing ligand, thiol group-containing ligand, which has a structure different from that of the first modifying group (A1); Organic-modified metal oxide nanoparticles selected from the group consisting of an amino group-containing ligand, a nitrate ligand, and a hydroxide ion. The method of claim 1,
Organic-modified metal oxide nanoparticles represented by the following formula (m01).
C01-L01-C02 ... (m01)
In the above formula (m01),
C01 is M ₆ O ₄ (OH) ₄ [X _a Y _b ], and 0 ≤ a ≤ 10 and 1 ≤ b ≤ 11 . C02 is M ₆ O ₄ (OH) ₄ [X _c Y _d ], and 0 ≤ c ≤ 10 and 1 ≤ d ≤ 11 . L01 is Xw, w = 24 - (a + b + c + d), and 2 ≤ w ≤ 12.
[M is the metal atom, a metal atom of a group 4 element, X is the first modifying group (A1), and Y is the second modifying group (A2)]. The method of claim 1,
wherein the metal atom is Zr, organically modified metal oxide nanoparticles. A solution containing the organic-modified metal oxide nanoparticles according to any one of claims 1 to 6 and a solvent. A resist composition containing the organic modified metal oxide nanoparticles according to any one of claims 1 to 6 and a solvent. A step of forming a resist film on a support by using the resist composition containing the organic modified metal oxide nanoparticles according to claim 8;
exposing the resist film;
and developing the resist film after the exposure to form a resist pattern.