Resist composition, laminate, and patterning process

Abstract

[Problem] In photolithography using high energy rays, a resist composition having excellent sensitivity, resolution, and LWR, is stable, and is easy to handle, a laminate comprising a resist film obtained from the resist composition, and a pattern forming method using the resist composition. [Solution] A resist composition characterized by comprising a metal complex represented by the following general formula (1) and a solvent. (In the formula, R is a hydrogen atom, a hydrocarbyl carbonyl group having 1 to 20 carbon atoms, or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom. X is a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom.)

Description

Technology Field

[0001] The present invention relates to a resist composition, a laminate, and a pattern forming method. Background Technology

[0002] With the expansion of the IoT market, there is an increasing demand for higher integration, higher speed, and lower power consumption of LSIs, and the miniaturization of pattern rules is progressing rapidly. In particular, logic devices are driving this miniaturization. As a cutting-edge miniaturization technology, mass production of 10 nm node devices is being carried out using double patterning, triple patterning, and quadro patterning of ArF immersion lithography, and the development of 7 nm node devices using next-generation 13.5 nm wavelength extreme ultraviolet (EUV) lithography is underway.

[0003] With the progress of miniaturization, image blurring caused by acid diffusion is becoming a problem (Non-patent Literature 1). It has been suggested that in order to secure resolution in fine patterns of processing dimensions 45 nm generation and beyond, control of acid diffusion is important, in addition to the improvement of dissolution contrast that has been conventionally proposed (Non-patent Literature 2). However, since chemical amplification resist compositions increase sensitivity and contrast through acid diffusion, if one attempts to suppress acid diffusion to the extreme by lowering the post-exposure bake (PEB) temperature or shortening the PEB time, the sensitivity and contrast are significantly reduced.

[0004] It is effective to suppress acid diffusion by adding an acid-generating agent that generates bulky acid. Therefore, copolymerizing an acid-generating agent of an onium salt having a polymerizable olefin in a polymer has been proposed. However, regarding the pattern formation of resist films with processing dimensions of 16 nm or more, it is thought that pattern formation cannot be achieved with chemically amplified resist compositions from the perspective of acid diffusion, and thus the development of non-chemically amplified resist compositions is required.

[0005] Polymethyl methacrylate (PMMA) can be cited as a material for non-chemical amplification resist compositions. PMMA is a positive-type resist material in which the main chain is cut by electron beam (EB) or EUV irradiation and the molecular weight is reduced, thereby improving solubility in organic solvent developers. However, because it does not have a ring structure, it has the disadvantage of low etching resistance and a large amount of outgassing during exposure.

[0006] Hydrogensilsesquioxane (HSQ) is a material for negative-type resist compositions that becomes insoluble in alkaline developers due to crosslinking caused by the condensation reaction of silanols generated by EB or EUV irradiation. Additionally, chlorine-substituted calixalene also functions as a material for negative-type resist compositions. Since these materials have small molecular sizes prior to crosslinking and do not undergo blurring due to acid diffusion, they exhibit low edge roughness and very high resolution, making them suitable for use as pattern transfer materials to indicate the resolution limit of an exposure device. However, these materials have insufficient sensitivity and require further improvement.

[0007] One factor that makes the development of materials for EUV lithography difficult is the low number of photons in EUV exposure. The energy of EUV is much higher than that of ArF excimer laser light, and the number of photons in EUV exposure is one-fourteenth that of ArF exposure. Furthermore, the dimensions of patterns formed by EUV exposure are less than half those of ArF exposure. For this reason, EUV exposure is susceptible to the effects of photon non-uniformity. Photon non-uniformity in the extreme wavelength synchrotron region is a physical phenomenon known as shot noise, and this effect cannot be eliminated. For this reason, so-called stochastics is attracting attention. Although the effects of shot noise cannot be eliminated, discussions are underway on how to reduce them. Due to the effects of shot noise, not only are dimensional uniformity (CDU) and line width roughness (LWR) increased, but a phenomenon in which holes become occluded with a probability of one in a million is also observed. If a hole is blocked, it results in a power failure and prevents the transistor from operating, which negatively affects the overall performance of the device.

[0008] As a method to reduce the impact of shot noise on the resist side, an inorganic resist composition with an element that absorbs a large amount of EUV as a nucleus has been proposed (Patent Document 1). However, the inorganic resist composition is relatively sensitive but is not yet sufficient and has many challenges such as insufficient solubility in solvents for the resist composition, storage stability, and defects.

[0009] Non-patent document 3 proposes a negative-type resist composition using a tin compound. This is a non-chemical amplification resist composition with a tin element, which has high EUV light absorption, as the main component. Although the stochastics are improved and the sensitivity and resolution are greatly improved, there are difficulties with stability, and the performance changes due to degradation during storage of the resist composition or the time elapsed from PEB to development (Post-PEB Delay: PPD). Prior art literature

[0010] Patent Document 1: Japanese Patent Publication No. 2015-108781

[0011] [Non-patent Literature 1] SPIE Vol. 5039 p1 (2003)[Non-patent Literature 2] SPIE Vol. 6520 p65203L-1 (2007)[Non-patent Literature 3] SPIE Vol. 9051 p90511B-1 (2014) The problem to be solved

[0012] The present invention is made in consideration of the above circumstances and aims to provide a resist composition that is excellent in sensitivity, resolution, and LWR, stable, and easy to handle in photolithography using high energy rays, a laminate comprising a resist film obtained from the resist composition, and a pattern forming method using the resist composition. means of solving the problem

[0013] To solve the above problem, the present invention provides a resist composition comprising a metal complex represented by the following general formula (1) and a solvent.

[0014]

[0015] (In the formula, R is a hydrogen atom, a hydrocarbyl carbonyl group having 1 to 20 carbon atoms, or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom. X is a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom.)

[0016] With such a resist composition, in photolithography using high-energy rays, sensitivity, resolution, and LWR are excellent, stable, and easy to handle.

[0017] In addition, in the present invention, as a laminate,

[0018] The substrate and,

[0019] A resist film obtained from the resist composition described above, on the substrate above.

[0020] Provides a laminate having

[0021] With such a laminate, the resist film exhibits high sensitivity and excellent limit resolution, and in addition to being effective for precise micro-machining, it also offers excellent storage stability.

[0022] At this time, it is preferable to further provide a resist lower layer between the substrate and the resist film.

[0023] In the present invention, such a laminate can be made.

[0024] In addition, the present invention, as a pattern forming method,

[0025] A process of forming a resist film on a substrate or on a resist lower layer of a substrate having a resist lower layer laminated thereon, using the resist composition described above, and

[0026] A process of exposing the above resist film to high-energy rays, and

[0027] A process of developing the above-mentioned exposed resist film using a developer solution

[0028] A pattern forming method characterized by including

[0029] With such a pattern forming method, it is possible to provide a pattern forming method using a resist composition that is stable and easy to handle, and has excellent sensitivity, resolution, and LWR in photolithography using high energy rays.

[0030] At this time, it is preferable to use electron beams or extreme ultraviolet rays as the high-energy rays.

[0031] In the pattern forming method of the present invention, it is preferable to use such high-energy rays. Effects of the invention

[0032] As described above, the resist composition of the present invention is very useful for forming fine patterns in photolithography using high energy rays, particularly EB lithography and EUV lithography, because it achieves both high sensitivity and high resolution, has excellent LWR, good stability, and is easy to handle. Brief explanation of the drawing

[0033] FIG. 1 is a schematic diagram showing an example of a laminate of the present invention. Specific details for implementing the invention

[0034] As previously mentioned, in photolithography using high energy rays, particularly EB lithography and EUV lithography, there was a need to develop a resist composition that is stable and easy to handle, has excellent sensitivity, resolution, and LWR, a laminate comprising a resist film obtained from the resist composition, and a pattern forming method using the resist composition.

[0035] As a result of repeated careful consideration to achieve the above objective, the inventors discovered that a resist composition having a metal complex having a specific structure as a main component provides a resist film that is highly effective for precise micro-processing, exhibiting high sensitivity, excellent resolution and LWR, and also excellent stability, and thus came to make the present invention.

[0036] That is, the present invention is a resist composition comprising a metal complex represented by the following general formula (1) and a solvent.

[0037]

[0038] (In the formula, R is a hydrogen atom, a hydrocarbyl carbonyl group having 1 to 20 carbon atoms, or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom. X is a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom.)

[0039] The present invention will be described in detail below, but the invention is not limited to these.

[0040] [Resist composition]

[0041] The resist composition of the present invention comprises a metal complex of a specific structure and a solvent.

[0042] [Metal complex]

[0043] The metal complex included in the resist composition of the present invention is represented by the following general formula (1). Since this metal complex has a high density of zinc atoms that have high absorption efficiency of EUV light, it has excellent sensitivity and resolution. In addition, because it has a hypophosphorus type ligand that stabilizes the complex with high binding energy with metal atoms and a ligand (X) that has low binding energy with metal atoms and high photodegradability, the resist composition of the present invention is not only even more sensitive, but also has improved stability over time during storage of the resist composition and stability following PEB.

[0044]

[0045] (In the formula, R is a hydrogen atom, a hydrocarbyl carbonyl group having 1 to 20 carbon atoms, or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom. X is a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom.)

[0046] In the above general formula (1), the two oxygen atoms (O) bonded to one phosphorus atom (P) are bonded with one single bond and the other double bond, but in this specification, for simplicity, the double bond is omitted and all are shown as single bonds.

[0047] In the above general formula (1), R is, respectively, a hydrogen atom, a hydrocarbyl carbonyl group having 1 to 20 carbon atoms, or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom. The hydrocarbyl portion of the hydrocarbyl group and the hydrocarbyl carbonyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a tert-pentyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group; Cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo[5.2.1.0 2,6 Examples include cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as decanyl groups, adamantyl groups, and adamantylmethyl groups; alkenyl groups having 2 to 20 carbon atoms, such as vinyl groups and 2-propenyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl groups and naphthyl groups; and groups obtained by combining these. Additionally, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, may include a hydroxyl group, a cyano group, a halogen atom, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a carbamate bond, a lactone ring, a sulfone ring, a carboxylic acid anhydride, etc. In the formula, each R may be the same or different.

[0048] In the above general formula (1), X is a hydrocarbyl group having 1 to 20 carbon atoms, which may each independently contain a halogen atom or a heteroatom. Examples of the halogen atom include fluorine, chlorine, bromine, iodine, etc. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. Specific examples include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl groups; Cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo[5.2.1.0 2,6 Examples include cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as decanyl groups, adamantyl groups, and adamantylmethyl groups; alkenyl groups having 2 to 20 carbon atoms, such as vinyl groups and 2-propenyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl groups and naphthyl groups; and groups obtained by combining these. Additionally, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, may include a hydroxyl group, a cyano group, a halogen atom, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a carbamate bond, a lactone ring, a sulfone ring, a carboxylic acid anhydride, etc. It is particularly preferable that the atom bonded to zinc in the above hydrocarbyl group is carbon. In the formula, each X may be the same or different.

[0049] Specific examples of the metal complex represented by the above general formula (1) include those shown below, but are not limited thereto. In addition, among the following formulas, Me is a methyl group and Ph is a phenyl group.

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] In the case where isomers are generated by the arrangement of ligands, the above metal complex may use a mixture of these isomers or use only a single isomer. Furthermore, in the case where the above metal complex consists of multiple types of ligands with different R or X, a single metal complex with completely controlled ratios of each ligand may be used, or a mixture of metal complexes with different ratios of each ligand may be used.

[0065] The above metal complex may be used as a single type or in combination of two or more types.

[0066] [solvent]

[0067] The resist composition of the present invention comprises an organic solvent as a solvent. As for the organic solvent, it is not particularly limited as long as it is capable of dissolving the metal complex and forming a film. Examples of such organic solvents include ketones such as cyclohexanone and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; and ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether. Examples include esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 2-hydroxyisobutyrate, tert-butyl acetate, cyclohexyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as γ-butyrolactone; carboxylic acids such as acetic acid and propionic acid; aromatics such as toluene, xylene, cresol, anisole, and benztrifluoride; halogenated hydrocarbons such as dichloromethane, chloroform, and carbon tetrachloride; and mixed solvents thereof.

[0068] The content of the organic solvent is preferably 200 to 20,000 parts by mass and more preferably 500 to 15,000 parts by mass with respect to 100 parts by mass of the metal complex.

[0069] It is presumed that the resist composition of the present invention enables contrast by changing the development resistance in the exposed and unexposed regions through the photodecomposition of the main component metal complex and subsequent aggregation or crosslinking reactions between the partially destroyed metal complexes. Since this reaction is not a catalytic reaction, the resist composition of the present invention functions as a non-chemical amplification type resist composition. Therefore, it is possible to achieve resolution even in fine regions where pattern formation is difficult with conventional chemical amplification resist compositions based on multi-component polymers. In particular, for EUV lithography, since the metal atoms have high EUV absorption capacity, the stochastics are improved, and the resist composition becomes one with excellent sensitivity and LWR. Furthermore, since the metal complex is structured in a thermally stable form, storage stability is also excellent. Additionally, there is no significant change in performance over time after PEB.

[0070] [Mining Agent]

[0071] The resist composition of the present invention may include a photogenerator as a component other than the metal complex and the solvent. By using a photogenerator, acid is generated in the exposed area, thereby promoting the cross-linking reaction of the metal complex. As for such a photogenerator, it is not particularly limited as long as it generates acid upon irradiation with high-energy rays, and any photogenerator known as a photogenerator for conventional chemically amplified resist compositions may be used; however, it is particularly preferable to generate sulfonic acid, imidic acid, or methic acid. Suitable photogenerators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate type acidgenerators. Specific examples of the above-mentioned photocatalytic agent include those described in paragraphs

[0122] to

[0142] of Japanese Patent Publication No. 2008-111103 and those described in paragraphs

[0127] to

[0193] of Japanese Patent Publication No. 2022-163697.

[0072] When the resist composition of the present invention includes the photocatalytic agent, the content thereof is preferably 0.01 to 20 mass% of the total solid content. In addition, in the present invention, solid content refers to the general term for components other than solvents among the total components of the resist composition. The photocatalytic agent may be used as a single type or as a combination of two or more types.

[0073] [Radical Capture Agent]

[0074] The resist composition of the present invention may include a radical scavenger as an additional component. By adding a radical scavenger, the photoreaction during photolithography can be controlled, thereby allowing the sensitivity to be adjusted.

[0075] As the above radical scavenger, hindered phenols, quinones, hindered amines, thiol compounds, etc. may be used. Specific examples of the above hindered phenols include dibutylhydroxytoluene and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). Specific examples of the above quinones include 4-methoxyphenol (methoquinone) and hydroquinone. Specific examples of the above hindered amines include 2,2,6,6-tetramethylpiperidine and 2,2,6,6-tetramethylpiperidine-N-oxyradical. Specific examples of the above thiols include dodecanethiol and hexadecanethiol.

[0076] When the resist composition of the present invention includes the radical scavenger, the content thereof is preferably 0.01 to 10 mass% of the total solid content. The radical scavenger may be used alone or in combination of two or more types.

[0077] [Surfactant]

[0078] The resist composition of the present invention may include a surfactant as an additional component. As for the surfactant, reference may be made to those described in Japanese Patent Publication No. 2010-215608 or Japanese Patent Publication No. 2011-016746. Among those described therein, FC-4430 (manufactured by 3M Corporation), Surfron (registered trademark) S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Olfin (registered trademark) E1004 (manufactured by Nisshin Kagaku Kogyo Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and oxetane ring-opening polymers represented by the following general formula (surf-1) are preferred.

[0079]

[0080] Among the above general formula (surf-1), R 1 It is a 2- to 4-valent aliphatic group having 2 to 5 carbon atoms. Examples of the above-mentioned aliphatic groups include the ethylene group, 1,4-butylene group, 1,2-propylene group, 2,2-dimethyl-1,3-propylene group, 1,5-pentylene group as divalent groups, and the following as trivalent or tetravalent groups.

[0081]

[0082] (In the formula, the dashed lines are bonding hands and are substructures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.)

[0083] Among these, 1,4-butylene groups, 2,2-dimethyl-1,3-propylene groups, etc. are preferred.

[0084] Rf is a trifluoromethyl group or a pentafluoroethyl group, preferably a trifluoromethyl group. m is an integer from 0 to 3, n is an integer from 1 to 4, and the sum of n and m is R 1The valence is an integer from 2 to 4. A is 1. B is an integer from 2 to 25, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. In addition, the arrangement of each constituent unit in the above general formula (surf-1) is not specified, and they may be combined in a block or randomly. The preparation of a partially fluorinated oxetane ring-opening polymer-based surfactant is described in detail in U.S. Patent No. 5650483, etc.

[0085] When the resist composition of the present invention includes the surfactant, the content thereof is preferably 0.001 to 20 parts by mass and more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the metal complex. The surfactant may be used alone or in combination of two or more types.

[0086] [Laminated]

[0087] In addition, in the present invention, as a laminate,

[0088] The substrate and,

[0089] A resist film obtained from the resist composition on the above substrate

[0090] Provides a laminate having

[0091] In the laminate of the present invention comprising a resist film obtained from the resist composition of the present invention, the resist film exhibits high sensitivity and excellent limit resolution, and is effective for precise micro-processing, in addition to having excellent storage stability. Therefore, the laminate of the present invention has a wide range of applications and is highly useful in resist process technology.

[0092] In addition, the laminate of the present invention may further comprise a resist lower layer film (2) between the substrate (3) and the resist film (1), such as the laminate (10) shown in FIG. 1.

[0093] If a resist underlayer is required for pattern formation, the resist underlayer may be appropriately placed between the substrate and the resist film.

[0094] The resist film is not particularly limited as long as it is obtained from the resist composition of the present invention. For example, it may be a film composed solely of the metal complex, or a film composed of a product in which at least a portion of the metal complex reacts with a substance in the environment (e.g., water, oxygen, solvent, etc.) during baking.

[0095] [Pattern Formation Method]

[0096] When the resist composition of the present invention is used in the manufacture of various integrated circuits, known lithography techniques may be applied. For example, a pattern formation method may include a process of forming a resist film on a substrate using the aforementioned resist composition, a process of exposing the resist film to high-energy rays, and a process of developing the exposed resist film.

[0097] That is, in the present invention, as a pattern forming method,

[0098] A process of forming a resist film on a substrate or on a resist lower layer of a substrate having a resist lower layer laminated thereon using the above resist composition, and

[0099] A process of exposing the above resist film to high-energy rays, and

[0100] A process of developing the above-mentioned exposed resist film using a developer solution

[0101] A pattern forming method including is provided.

[0102] First, the resist composition of the present invention is applied, for example, to a substrate for manufacturing an integrated circuit, or to a substrate on which a resist sublayer film is laminated (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.), or to a substrate for manufacturing a mask circuit, or to a substrate on which a resist sublayer film is laminated (Cr, CrO, CrON, MoSi2, SiO2, etc.), by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, so that the thickness of the coating film is 0.01 to 2 μm. The coating film obtained in this way can be pre-baked, for example, on a hot plate, preferably at 60 to 200°C for 10 seconds to 30 minutes, more preferably at 80 to 180°C for 30 seconds to 20 minutes, to form a resist film. In addition, the term "resist underlayer" refers to a film formed between a substrate and a resist film in a multilayer resist process, and the resist underlayer is not particularly limited and can use conventionally known materials.

[0103] Next, the resist film is exposed using high-energy rays. Specific examples of the high-energy rays include ultraviolet rays (g-rays (436 nm), h-rays (405 nm), i-rays (365 nm), etc.), far-ultraviolet rays, electron beams (EB), extreme ultraviolet rays (EUV), X-rays, soft X-rays, excimer laser light (KrF excimer laser light, ArF excimer laser light, etc.), gamma rays, synchrotron radiation, etc. As high-energy rays, it is preferable to use i-rays, KrF excimer laser light, ArF excimer laser light, electron beams, or extreme ultraviolet rays. When ultraviolet rays, far-ultraviolet rays, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc., are used as the high-energy rays, irradiation is performed directly or using a mask to form a target pattern, such that the exposure amount is preferably about 1 to 300 mJ / cm², more preferably about 10 to 200 mJ / cm². When EB is used as the high-energy rays, drawing is performed directly or using a mask to form a target pattern, such that the exposure amount is preferably about 0.1 to 2000 μC / cm², more preferably about 0.5 to 1500 μC / cm². Furthermore, the resist composition of the present invention is particularly suitable for fine patterning using EB or EUV among high-energy rays. That is, it is preferable to use electron beams or extreme ultraviolet rays as the high-energy rays.

[0104] In order to accelerate or complete the reaction after exposure, PEB may be performed. When performing PEB, it is preferable to perform it on a hot plate or in an oven after exposure, preferably at 30 to 200°C for 10 seconds to 30 minutes, more preferably at 60 to 180°C for 30 seconds to 20 minutes.

[0105] The method of development performed after exposure or after PEB may be either wet development or dry development. In the case of wet development, alkaline development or organic solvent development may be applied, but organic solvent development is preferred when forming a pattern with the resist composition of the present invention. Wet development is preferably performed on the exposed resist film by conventional methods such as the dip method, puddle method, or spray method for 3 seconds to 3 minutes, more preferably 5 seconds to 2 minutes, to form the desired pattern. Since the resist composition of the present invention is a negative type, the portion exposed to light becomes insoluble in the developer solution, and the portion not exposed is dissolved.

[0106] As organic solvents used as a developer, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutylketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, cyclohexyl acetate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl penthenate, methyl crotonicate, ethyl crotonicate, methyl propionate, ethyl propionate, 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, Examples include isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, 2-phenylethyl acetate, dichloromethane, chloroform, carbon tetrachloride, formic acid, acetic acid, propionic acid, etc. These organic solvents may be used individually or in a mixture of two or more types.

[0107] After development, rinsing is performed as needed. As for the rinsing solution, a solvent that is mixed with the developer and does not dissolve the resist film is preferred. As such a solvent, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms are preferably used.

[0108] Specific examples of the above alcohol having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol. Examples include 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, etc.

[0109] Specific examples of the above ether compounds having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, di-n-hexyl ether, etc.

[0110] Specific examples of the above-mentioned alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Specific examples of the above-mentioned alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Specific examples of the above-mentioned alkynes having 6 to 12 carbon atoms include hexine, heptene, octene, etc.

[0111] Specific examples of the above-mentioned aromatic solvents having 6 to 12 carbon atoms include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, etc.

[0112] By rinsing, the breakdown of the resist pattern or the occurrence of defects can be reduced. In addition, rinsing is not strictly necessary, and the amount of solvent used can be reduced by not rinsing.

[0113] Dry development can also be applied as a development method in the pattern forming method of the present invention. Dry development is a process in which either the exposed area or the unexposed area is removed by a gas-based etching process without using a developer solution. In the case of the present invention, a desired pattern can be formed by removing the unexposed area using an etching gas. For dry etching, a gas containing nitrogen, helium, argon, carbon dioxide, or carbon monoxide for dilution is preferably used with a gas containing oxygen, hydrogen, ammonia, or halogen.

[0114] Examples

[0115] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited thereto.

[0116] The metal complex used in the example is represented by the following formulas (M-1) to (M-2).

[0117]

[0118] The metal complex represented by the above general formulas (M-1) and (M-2) was synthesized with reference to Nature Communications, 2016, 7, 13008.

[0119] [1] Preparation of a resist composition

[0120] [Examples 1-1 to 1-4, Comparative Example 1-1]

[0121] Each component was dissolved in a solvent according to the composition shown in Table 1, and the resulting solution was filtered through a 0.2 μm Teflon (registered trademark) filter to prepare the resist compositions R-1 to R-4 of the present invention and the comparative resist composition CR-1.

[0122]

[0123] In Table 1, component A is a metal complex, component B is a photogenerative agent, and component C is a radical scavenger. The structures of the metal complexes (M-1) to (M-2) used as component A are as described above. Details of components B and C are as follows.

[0124] · P-1: Triphenylsulfonium tosylate

[0125] · Sc-1: Dibutylhydroxytoluene

[0126] In Table 1, PGMEA is propylene glycol monomethyl ether acetate.

[0127] In Table 1, CM-1 (tin compound) used in Comparative Example 1-1 was synthesized according to Angewandte Chemie, International Edition (2017), 56(34), 10140-10144. The structure of CM-1 is as follows.

[0128]

[0129] [2] EB lithography evaluation

[0130] [Examples 2-1–2-4, Comparative Example 2-1]

[0131] Each resist composition (R-1 to R-4, CR-1) was spin-coated onto a Si substrate on which an anti-reflective film DUV-42 manufactured by Nissan Chemical Co., Ltd. was formed to a film thickness of 60 nm, and a resist film with a thickness of 40 nm was fabricated by pre-baking at 100°C for 60 seconds using a hot plate. The resist film was exposed using an EB lithography device (ELS-F125, acceleration voltage 125 kV) manufactured by Erionics, and a pattern was formed by performing PEB on a hot plate at the temperature listed in Table 2 for 60 seconds and developing for 30 seconds using 2-heptanone as the developer. As a result, a negative-type line and space (LS) pattern with a space width of 20 nm and a pitch of 40 nm was obtained. For the obtained LS pattern, sensitivity, LWR, and limiting resolution were evaluated according to the following method. The results are shown in Table 2.

[0132] [Sensitivity Evaluation]

[0133] The above LS pattern was observed with an electron microscope to determine the optimal exposure amount Eop (μC / cm²) at which an LS pattern with a space width of 20 nm and a pitch of 40 nm is obtained, and this was used as the sensitivity.

[0134] [LWR Evaluation]

[0135] The LS pattern obtained by irradiating with the optimal exposure amount was measured at 10 locations along the length of the space width using a CD-SEM (CG-5000) manufactured by Hitachi High-Tech Corporation, and a value three times the standard deviation (σ) (3σ) was calculated from the result and set as LWR. The smaller this value, the less roughness and the more uniform the space width pattern is obtained.

[0136] [Limit Resolution Evaluation]

[0137] The limit line width (nm) at which a pattern is formed by gradually increasing the exposure amount from the optimal exposure amount was determined using a measuring SEM (CG-6300) manufactured by Hitachi High-Tech Corporation, and this was defined as the limit resolution (nm). A smaller value indicates superior limit resolution and the ability to form finer patterns.

[0138] [Evaluation of Post-Exposure Stability]

[0139] After exposure at the optimal exposure amount, PEB and development were performed under the above conditions. At that time, a wafer (PPD0h) was developed to form a pattern without leaving it after PEB, and a wafer (PPD6h) was developed to form a pattern after leaving it for 6 hours after PEB. The line widths of these wafers were determined using a measuring SEM (CG-6300) manufactured by Hitachi High-Tech Corporation, and the change in line width (CD) (ΔPPD) due to leaving it after exposure was calculated. The results are shown in Table 2.

[0140]

[0141] From the results shown in Table 2, it was found that the resist compositions R-1 to R-4 of the present invention exhibited excellent LWR and limiting resolution in the formation of negative patterns by organic solvent development using EB lithography. In addition, it was confirmed that there was little change in CD even after exposure and that the composition remained stable even after pattern formation. Furthermore, since the resist compositions of the present invention have a high density of zinc atoms with high EUV light absorption capacity, it is expected that they will be significantly sensitive in EUV lithography.

[0142] In this regard, it was found that the comparative resist composition CR-1 lagged behind in LWR and limit resolution when forming a negative pattern by organic solvent development using EB lithography. In addition, it was confirmed that there was a large change in CD even after exposure and that it was unstable even after pattern formation.

[0143] [3] Preservation stability evaluation

[0144] [Examples 3-1 to 3-4, Comparative Example 3-1]

[0145] Under room temperature (20±5℃) conditions, each resist composition (CR-1 to CR-4, CR-1) was visually inspected for precipitation after being left for a specific period. At this time, ○ was used for those that could be stored without precipitation for 6 months or more, and × was used for those that developed precipitation in less than 6 months. The results are shown in Table 3.

[0146]

[0147] From the results shown in Table 3, the resist compositions R-1 to R-4 of the present invention were found to have excellent storage stability and good handling.

[0148] In this regard, the comparative resist composition CR-1 was found to have poor handling characteristics due to its inferior storage stability.

[0149] Furthermore, the present invention is not limited to the above embodiments. The above embodiments are examples, and any configuration substantially identical to the technical concept described in the claims of the present invention and any function that exhibits the same effect are included within the technical scope of the present invention. Explanation of the symbols

[0150] 1: Resist film, 2: Resist underlayer, 3: Substrate, 10: Laminate.

Claims

Claim 1 A resist composition characterized by comprising a metal complex represented by the following general formula (1) and a solvent. (In the formula, R is a hydrogen atom, a hydrocarbyl carbonyl group having 1 to 20 carbon atoms, or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom. X is a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms that may include a heteroatom.) Claim 2 A laminate characterized by comprising, as a laminate, a substrate and, on the substrate, a resist film obtained from the resist composition described in claim 1. Claim 3 A laminate according to paragraph 2, characterized by further comprising a resist lower layer between the substrate and the resist film. Claim 4 A pattern forming method characterized by comprising: a process of forming a resist film on a substrate or on a resist lower layer of a substrate having a resist lower layer laminated thereon, using a resist composition described in claim 1; a process of exposing the resist film to high-energy rays; and a process of developing the exposed resist film using a developer. Claim 5 A pattern forming method according to claim 4, characterized by using electron beams or extreme ultraviolet rays as the high-energy rays.

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