Resist composition, laminate, and pattern forming method

Abstract

The present application relates to a resist composition, a laminate, and a pattern forming method. The present application provides a resist composition which is excellent in sensitivity, resolution, and LWR, and is also easy to stably handle in optical lithography using a high-energy ray, a laminate including a resist film obtained from the resist composition, and a pattern forming method using the aforementioned resist composition. The means for solving the problem is a resist composition characterized by comprising a metal complex represented by the following general formula (1) and a solvent.[Chemical Formula 1]

Description

Technical Field

[0001] This invention relates to resist compositions, laminates, and methods for forming patterns. Background Technology

[0002] With the expansion of the IoT market, there are increasing demands for higher integration, higher speed, and lower power consumption in LSI (Light Silica) technology, and the miniaturization of patterning is also progressing rapidly. In particular, logic devices are leading the way in miniaturization. Regarding the most advanced miniaturization technologies, mass production of 10nm node devices obtained through dual, triple, and quadruple patterning using ArF immersion lithography is already underway, and research is progressing on the next generation of 7nm node devices obtained through 13.5nm extreme ultraviolet (EUV) lithography.

[0003] As miniaturization progresses, image blurring caused by acid diffusion has become a problem (Non-Patent Literature 1). To ensure the resolution of fine patterns with a processing size of less than 45 nm, it has been proposed that not only is the improvement of dissolution contrast, as previously advocated, important, but also the control of acid diffusion is crucial (Non-Patent Literature 2). However, since chemically amplified resist compositions improve sensitivity and contrast through acid diffusion, if acid diffusion is suppressed to the limit by lowering the post-exposure baking (PEB) temperature or shortening the PEB time, sensitivity and contrast will be significantly reduced.

[0004] Adding acid-generating agents that produce bulky acids is effective in suppressing acid diffusion. Therefore, it has been proposed to use onium salts of polymerizable olefins as acid-generating agents in polymer copolymerization. However, considering acid diffusion, in the patterning of resist films with dimensions smaller than 16 nm, it is believed that chemically amplified resist compositions are no longer suitable for patterning, and the development of non-chemically amplified resist compositions is desired.

[0005] Materials used in non-chemically amplified resist compositions include polymethyl methacrylate (PMMA). PMMA is a positive resist material whose solubility in organic solvent developers is improved by breaking the main chain and reducing the molecular weight through electron beam (EB) or EUV irradiation. However, because it does not have a ring structure, its disadvantages include low etching resistance and a large amount of gas released during exposure.

[0006] Hydrosilsesquioxane (HSQ) is a cross-linked material formed by the condensation reaction of silanols produced by EB or EUV irradiation, thereby becoming a negative resist component insoluble in alkaline developers. Additionally, chlorinated calixarnes also function as negative resist components. Because of their small molecular size before cross-linking and the absence of blurring due to acid diffusion, these materials can be used as pattern transfer materials with low edge roughness and very high resolution, showcasing the resolving limits of exposure devices. However, their sensitivity is insufficient and further improvement is needed.

[0007] One of the main reasons hindering material development for EUV lithography applications is the low photon count in EUV exposure. EUV energy is significantly higher than ArF excimer lasers, and the photon count in EUV exposure is only one-fourteenth that of ArF exposure. Furthermore, the size of patterns formed by EUV exposure is less than half that of ArF exposure. Therefore, EUV exposure is susceptible to variations in photon count. These variations in photon count in extremely short wavelength emission regions constitute shot noise, a physical phenomenon that cannot be eliminated. Consequently, so-called stochastics have become a concern. While shot noise cannot be eliminated, methods to reduce its impact have been discussed. Due to shot noise, not only do dimensional uniformity (CDU) and linewidth roughness (LWR) increase, but there is also a one in a million chance of observing hole blockage. Hole blockage leads to poor conductivity and transistor malfunction, thus negatively impacting overall device performance.

[0008] As a method to reduce the impact of shot noise from the perspective of resist, it has been proposed to use inorganic resist compositions with elements that have high absorption in EUV as the core (Patent Document 1). However, although inorganic resist compositions have high sensitivity, they are still insufficient, and there are many problems such as insufficient solubility of the resist composition in the solvent, storage stability, and defects.

[0009] Non-patent literature 3 proposes a negative resist composition using tin compounds. This is a non-chemically amplified resist composition with tin, which has high EUV light absorption, as the main component. Although randomness is improved and sensitivity / resolution is significantly improved, problems exist, such as poor stability, degradation of the resist composition during storage, and performance changes due to the post-PEB delay (PPD) after PEB placement.

[0010] Existing technical documents

[0011] Patent documents

[0012] [Patent Document 1] Japanese Patent Application Publication No. 2015-108781

[0013] Non-patent literature

[0014] [Non-Patent Literature 1] SPIE Vol.5039 p1 (2003)

[0015] [Non-Patent Literature 2] SPIE Vol.6520 p65203L-1 (2007)

[0016] [Non-Patent Literature 3] SPIE Vol.9051 p90511B-1(2014) Summary of the Invention

[0017] [The problem that the invention aims to solve]

[0018] The present invention was made in view of the foregoing circumstances, and aims to provide a resist composition with excellent sensitivity, resolution and LWR and easy and stable operation in optical lithography using high-energy rays, a laminate comprising a resist film obtained from the resist composition, and a pattern forming method using the aforementioned resist composition.

[0019] [Methods for solving the problem]

[0020] To address the aforementioned issues, the present invention provides a resist composition comprising a metal complex represented by the following general formula (1) and a solvent.

[0021] [Chemistry 1]

[0022]

[0023] (In the formula, R is a hydrogen atom, a hydrocarbon carbonyl group with 1 to 20 carbon atoms, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. X is a halogen atom or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms.)

[0024] If the resist composition is such, it will have excellent sensitivity, resolution, and LWR in optical lithography using high-energy rays, and will also be easy to operate stably.

[0025] Furthermore, the present invention provides a laminate comprising:

[0026] substrate, and

[0027] A resist film obtained on the substrate from the resist composition as described above.

[0028] If it is such a laminate, the resist film has high sensitivity and excellent limiting resolution, which is not only effective for precision micro-machining, but also has excellent placement stability.

[0029] At this time, a lower resist film is preferably provided between the aforementioned substrate and the aforementioned resist film.

[0030] This invention can produce such laminates.

[0031] Furthermore, the present invention provides a pattern forming method, characterized by comprising the following steps:

[0032] Using the resist composition described above, a resist film is formed on a substrate, or on the aforementioned resist lower layer film of a substrate to which a resist lower layer film is laminated.

[0033] The aforementioned resist film was exposed to high-energy rays, and

[0034] The previously exposed resist film was developed using a developer.

[0035] Such a patterning method can be provided for optical lithography using high-energy rays, and can be used to pattern resist compositions with excellent sensitivity, resolution, and LWR, and can also be operated stably.

[0036] At this point, electron beams or extreme ultraviolet radiation should be used as the aforementioned high-energy rays.

[0037] In the pattern forming method of the present invention, it is preferable to use such high-energy rays.

[0038] [The effects of the invention]

[0039] As described above, the resist composition of the present invention is highly sensitive, highly resolving, and has excellent LWR in optical lithography using high-energy rays, especially in EB lithography and EUV lithography. Furthermore, it has good stability and is easy to operate, making it very useful in the formation of fine patterns. Attached Figure Description

[0040] [ Figure 1 [This is a schematic diagram illustrating an example of a laminate of the present invention.] Detailed Implementation

[0041] As mentioned above, there is a need for the development of a resist composition that has excellent sensitivity, resolution, and LWR, and is easy to operate stably, especially in optical lithography using high-energy rays, particularly in EB lithography and EUV lithography; a laminate containing a resist film obtained from the resist composition; and a patterning method using the aforementioned resist composition.

[0042] In order to achieve the aforementioned objectives, the inventors conducted repeated and in-depth research, and as a result, obtained insights into a resist composition with a metal complex having a specific structure as the main component, which has high sensitivity, excellent resolution and LWR, and provides a resist film with excellent stability, which is extremely effective for precision micro-machining, and thus completed the present invention.

[0043] That is, the present invention is a corrosion resist composition comprising a metal complex represented by the following general formula (1) and a solvent.

[0044] [Chemistry 2]

[0045]

[0046] (In the formula, R is a hydrogen atom, a hydrocarbon carbonyl group with 1 to 20 carbon atoms, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. X is a halogen atom or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms.)

[0047] The present invention will now be described in detail, but the present invention is not limited thereto.

[0048] [Resist Composition]

[0049] The resist composition of the present invention comprises a metal complex with a specific structure and a solvent.

[0050] [Metal complex]

[0051] The metal complex contained in the resist composition of the present invention is represented by the following general formula (1). This metal complex has a high density of zinc atoms with high absorption efficiency for EUV light, thus exhibiting excellent sensitivity and resolution. Furthermore, due to the presence of a hypophosphite-type ligand with high bonding energy to metal atoms that stabilizes the complex, and a ligand (X) with low bonding energy to metal atoms that has high photodegradability, the resist composition of the present invention not only has higher sensitivity but also improves the long-term stability of the resist composition during storage and the subsequent stability of PEB.

[0052] [Chemistry 3]

[0053]

[0054] (In the formula, R is a hydrogen atom, a hydrocarbon carbonyl group with 1 to 20 carbon atoms, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. X is a halogen atom or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms.)

[0055] In the above general formula (1), one of the two oxygen atoms (O) bonded to a phosphorus atom (P) is bonded by a single bond and the other by a double bond. However, in this specification, for convenience, the double bond is omitted and all are represented as single bonds.

[0056] In the above general formula (1), R is independently a hydrogen atom, a hydrocarbon carbonyl group with 1 to 20 carbon atoms, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. The hydrocarbon base of the aforementioned hydrocarbon group and hydrocarbon carbonyl group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, etc., alkyl groups with 1 to 20 carbon atoms; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norcamphenyl, tricyclic [5.2.1.0] 2,6[Cyclic saturated hydrocarbon groups with 3 to 20 carbon atoms, such as decyl, adamantyl, and adamantylmethyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl and 2-propenyl; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups may be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- group in the aforementioned hydrocarbon groups may also be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, the groups may contain hydroxyl, cyano, halogen, carbonyl, ether, thioether, ester, sulfonate, carbonate, carbamate, lactone, sulfonyl, or carboxylic anhydride groups. In the formula, each R may be the same or different.]

[0057] In the above general formula (1), X is independently a halogen atom or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. The hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, etc., alkyl groups with 1 to 20 carbon atoms; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norcamphenyl, tricyclic [5.2.1.0] 2,6 [Cyclic saturated hydrocarbon groups with 3 to 20 carbon atoms, such as decyl, adamantyl, and adamantylmethyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl and 2-propenyl; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups may be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- group in the aforementioned hydrocarbon groups may also be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, the groups may contain hydroxyl, cyano, halogen, carbonyl, ether, thioether, ester, sulfonate, carbonate, carbamate, lactone, sulfonate, or carboxylic anhydride groups. The atom bonded to zinc in the aforementioned hydrocarbon groups is preferably carbon. In the formula, each X may be the same or different.]

[0058] Specific examples of metal complexes represented by the above general formula (1) are shown below, but are not limited to these. Additionally, in the following formulas, Me represents methyl and Ph represents phenyl.

[0059] [Chemistry 4]

[0060]

[0061] [Chemistry 5]

[0062]

[0063] [Chemistry 6]

[0064]

[0065] [Chemistry 7]

[0066]

[0067] [Chemistry 8]

[0068]

[0069] [Chemistry 9]

[0070]

[0071] [Chemistry 10]

[0072]

[0073] [Chemistry 11]

[0074]

[0075] [Chemistry 12]

[0076]

[0077] [Chemistry 13]

[0078]

[0079] [Chemistry 14]

[0080]

[0081] [Chemistry 15]

[0082]

[0083] [Chemistry 16]

[0084]

[0085] [Chemistry 17]

[0086]

[0087] When the aforementioned metal complex produces isomers due to the configuration of the ligands, a mixture of these isomers can be used, or only a single isomer can be used. Furthermore, when the aforementioned metal complex is composed of multiple ligands where R or X are different, a single metal complex with completely controlled ratios of each ligand can be used, or a mixture of metal complexes with different ratios of each ligand can be used.

[0088] The aforementioned metal complexes can be used alone or in combination of two or more.

[0089] [solvent]

[0090] The resist composition of the present invention includes an organic solvent as a solvent. There are no particular limitations on the organic solvent, as long as it can dissolve the aforementioned metal complex and form 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; 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; and propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate... Esters such as esters, 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 trifluorotoluene; halogenated hydrocarbons such as dichloromethane, chloroform, and carbon tetrachloride; and mixed solvents.

[0091] The content of the aforementioned organic solvent relative to 100 parts by mass of the aforementioned metal complex is preferably 200 to 20,000 parts by mass, and more preferably 500 to 15,000 parts by mass.

[0092] It is speculated that the resist composition of the present invention exhibits contrast by altering the development resistance between the exposed and unexposed areas through the photodecomposition of the metal complex, which is the main component, and the subsequent aggregation or cross-linking reaction between the partially destroyed metal complexes. This reaction is not catalytic; therefore, the resist composition of the present invention functions as a non-chemically amplified resist composition. Thus, even in fine areas where pattern formation is difficult, resolution can be achieved with chemically amplified resist compositions using known multi-component polymers as the main component. Especially in EUV lithography, the aforementioned metal atoms have high EUV absorption capacity, thus improving stochastics and resulting in a resist composition with excellent sensitivity and low luminous flux (LWR). Furthermore, the aforementioned metal complexes converge to a thermally stable structure, resulting in excellent storage stability. Moreover, the performance does not change significantly over time after PEB.

[0093] [Photoacid Generator]

[0094] The resist composition of the present invention may also include a photoacid generator as a component other than the metal complex and solvent. By using a photoacid generator to generate acid in the exposed area, it is expected to promote the cross-linking reaction of the metal complex. Such a photoacid generator is not particularly limited as long as it generates acid by irradiation with high-energy rays, but known photoacid generators used in known chemically amplified resist compositions can be used, but those that generate sulfonic acid, imide acid, or methyl acid are particularly preferred. Ideal photoacid generators include: sulfonium salts, sulfonyl diazomethanes, N-sulfonyloxyimides, oxime-O-sulfonate type acid generators, etc. Specific examples of the aforementioned photoacid generators can be listed as those described in paragraphs

[0122] to

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

[0127] to

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

[0095] When the resist composition of the present invention includes the aforementioned photoacid generating agent, its content in the total solid components is preferably 0.01 to 20% by mass. Furthermore, the term "solid components" in the present invention refers to all components of the resist composition other than the solvent. The aforementioned photoacid generating agent may be used alone or in combination of two or more.

[0096] [Free radical scavengers]

[0097] The resist composition of the present invention may also include free radical scavengers as other components. By adding free radical scavengers, the photoresponse in optical lithography can be controlled, thereby adjusting the sensitivity.

[0098] The aforementioned free radical scavengers can include hindered phenols, quinones, hindered amines, and thiols. Specific examples of hindered phenols include butylated hydroxytoluene and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). Specific examples of quinones include 4-methoxyphenol (formone) and hydroquinone. Specific examples of hindered amines include 2,2,6,6-tetramethylpiperidine and 2,2,6,6-tetramethylpiperidine-N-oxy radical. Specific examples of thiols include dodecanethiol and hexadecanethiol.

[0099] When the resist composition of the present invention contains the aforementioned free radical scavenger, its content in the total solid components is preferably 0.01 to 10% by mass. The aforementioned free radical scavenger may be used alone or in combination of two or more.

[0100] [surfactant]

[0101] The resist composition of the present invention may also include surfactants as other components. The aforementioned surfactants can be referred to in Japanese Patent Application Publication Nos. 2010-215608 and 2011-016746. Among these, FC-4430 (manufactured by 3M Corporation), SURFLON (registered trademark) S-381 (manufactured by AGC SEIMI CHEMICAL), OLFINE (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC SEIMI CHEMICAL), and oxane ring-opening polymers represented by the following general formula (surf-1) are preferred.

[0102] [Chemistry 18]

[0103]

[0104] In the above general formula (surf-1), R 1 It is an aliphatic group with 2 to 5 carbon atoms, ranging from 2 to 4 valences. Among the aforementioned aliphatic groups, examples of 2 valence groups include: ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentane, etc., while examples of 3 valence or 4 valence groups include the following.

[0105] [Chemistry 19]

[0106]

[0107] (In the formula, the dashed lines represent atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and neopentyl tertrol, respectively.)

[0108] Among these, 1,4-butylene, 2,2-dimethyl-1,3-propylene, etc. are preferred.

[0109] Rf is either trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. 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. 1 The valence of A 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. Furthermore, the arrangement of the constituent units in the above general formula (surf-1) is not specified; they can be block-bonded or randomly bonded. For details on the manufacture of surfactants based on partially fluorinated oxyheterocyclic butane ring-opening polymer systems, please refer to the specification of US Patent No. 5,650,483, etc.

[0110] When the corrosion resist composition of the present invention contains the aforementioned surfactant, its content relative to 100 parts by weight of the aforementioned metal complex is preferably 0.001 to 20 parts by weight, more preferably 0.1 to 10 parts by weight. The aforementioned surfactant may be used alone or in combination of two or more.

[0111] [Layered Body]

[0112] Furthermore, the present invention provides a laminate comprising:

[0113] substrate, and

[0114] A resist film obtained on the substrate from the above-mentioned resist composition.

[0115] In the laminate of the present invention, which comprises a resist film obtained from the resist composition of the present invention, the resist film exhibits high sensitivity and excellent limiting resolution, making it effective not only for precision micro-machining but also for excellent placement stability. Therefore, the laminate of the present invention has a wide range of applications and is highly useful in resist treatment technology.

[0116] Furthermore, the laminate of the present invention, for example, Figure 1 The laminate 10 shown may also have a lower resist film 2 between the substrate 3 and the resist film 1.

[0117] When pattern formation requires a photoresist underlayer, the photoresist underlayer can be appropriately positioned between the substrate and the photoresist film.

[0118] 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 aforementioned metal complex, or it may be a film composed of a product obtained by reacting at least a portion of the aforementioned metal complex with substances in the environment (e.g., water, oxygen, solvents, etc.) through baking.

[0119] [Pattern Formation Method]

[0120] When the resist composition of the present invention is used in the manufacture of various integrated circuits, known photolithography techniques can be applied. For example, a patterning method may include the steps of forming a resist film on a substrate using the aforementioned resist composition, exposing the aforementioned resist film to high-energy rays, and developing the exposed resist film.

[0121] That is, the present invention provides a pattern forming method, comprising the following steps:

[0122] Using the above-described resist composition, a resist film is formed on a substrate, or on the aforementioned resist lower layer film of a substrate to which a resist lower layer film is laminated.

[0123] The aforementioned resist film was exposed to high-energy rays, and

[0124] The previously exposed resist film was developed using a developer.

[0125] First, the resist composition of the present invention is applied, for example, by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or blade coating, to a substrate for integrated circuit manufacturing, or a substrate on which a resist underlayer film (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective film, etc.) is laminated, to a substrate for mask circuit manufacturing, or a substrate on which a resist underlayer film (Cr, CrO, CrON, MoSi2, SiO2, etc.) is laminated. The resulting coating film can then be pre-baked, for example, on a hot plate at 60-200°C for 10 seconds to 30 minutes, preferably at 80-180°C for 30 seconds to 20 minutes, to form a resist film. In addition, the so-called photoresist underlayer film refers to the film formed between the substrate and the photoresist film in the process of multilayer photoresist treatment, and the aforementioned photoresist underlayer film is not particularly limited and can use those known in the past.

[0126] Then, the aforementioned photoresist film is exposed using high-energy radiation. Specific examples of such high-energy radiation include: ultraviolet rays (gamma rays (436nm), h-rays (405nm), i-rays (365nm), etc.), far ultraviolet radiation, electron beams (EB), extreme ultraviolet radiation (EUV), X-rays, soft X-rays, excimer lasers (KrF excimer lasers, ArF excimer lasers, etc.), gamma rays, synchrotron radiation, etc. I-rays, KrF excimer lasers, ArF excimer lasers, electron beams, or extreme ultraviolet radiation are preferred for high-energy radiation. When using ultraviolet radiation, far ultraviolet radiation, EUV, X-rays, soft X-rays, excimer lasers, gamma rays, synchrotron radiation, etc., the exposure dose should be approximately 1~300 mJ / cm², either directly or using a mask to form the desired pattern. 2 The optimal value is approximately 10~200 mJ / cm. 2 Irradiation is performed in a manner that allows for direct exposure. When using EB as a high-energy ray, either directly or using a mask to form the desired pattern, the exposure dose should be approximately 0.1~2000 μC / cm. 2 The optimal value is approximately 0.5~1500 μC / cm. 2 The resist composition of the present invention is depicted in a manner that is particularly suitable for fine patterning under high-energy radiation, such as EB or EUV. That is, electron beams or extreme ultraviolet light are preferable as the aforementioned high-energy radiation.

[0127] PEB can also be performed to promote or complete the post-exposure reaction. When performing PEB, it is advisable to perform it after exposure on a heated plate or in an oven, under conditions preferably 30~200°C for 10 seconds to 30 minutes, more preferably 60~180°C for 30 seconds to 20 minutes.

[0128] The development method performed after exposure or PEB can be either wet development or dry development. In the case of wet development, alkaline development or organic solvent development can be used; when forming patterns with the resist composition of the present invention, organic solvent development is preferred. Wet development is preferably performed for 3 seconds to 3 minutes, more preferably 5 seconds to 2 minutes, using common methods such as dip, immersion, or spraying to apply the exposed resist film to form the desired pattern. Because the resist composition of the present invention is negative, the exposed portions do not dissolve in the developing solution, while the unexposed portions dissolve.

[0129] Organic solvents used as developing solutions include: 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, propyl formate, cyclohexyl acetate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl valerate, methyl crotonate, ethyl crotonate, propionic acid. Methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl phenylethyl acetate, 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 can be used alone or in combination of two or more.

[0130] After development, rinsing should be performed as needed. The rinsing solution should preferably be a solvent that is miscible with the developer and does not dissolve the resist film. Suitable solvents include alcohols with 3 to 10 carbon atoms, ether compounds with 8 to 12 carbon atoms, alkanes with 6 to 12 carbon atoms, alkenes, alkynes, and aromatic solvents.

[0131] Specific examples of alcohols with 3 to 10 carbon atoms include: n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentanol, neopentanol, 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, 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.

[0132] Specific examples of the aforementioned ether compounds with 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.

[0133] Specific examples of alkanes with 6-12 carbon atoms include: hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Specific examples of alkenes with 6-12 carbon atoms include: hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Specific examples of alkynes with 6-12 carbon atoms include: hexyne, heptyne, octyne, etc.

[0134] Specific examples of solvents with 6 to 12 carbon atoms include toluene, xylene, ethylbenzene, cumene, tert-butylbenzene, mesitylene, etc.

[0135] Rinsing can reduce the collapse of the resist pattern and the formation of defects. Furthermore, rinsing is not always necessary; omitting rinsing can reduce solvent usage.

[0136] The developing method in the pattern forming method of the present invention can also be applied to dry developing. Dry developing refers to developing a pattern by using an etching step performed with gas to remove either the exposed or unexposed areas without using a developing solution. In the case of the present invention, the unexposed areas can be removed using an etching gas, thereby forming the desired pattern. Dry etching preferably uses a gas containing oxygen, hydrogen, ammonia, or halogens, but with dilution agents such as nitrogen, helium, argon, carbon dioxide, or carbon monoxide.

[0137] [Example]

[0138] The present invention will now be described in detail using examples and comparative examples, but the present invention is not limited thereto.

[0139] The metal complexes used in the examples are represented by the following formulas (M-1) to (M-2).

[0140] [Chemistry 20]

[0141]

[0142] The metal complexes represented by the above general formulas (M-1) and (M-2) were synthesized with reference to Nature Communications, 2016, 7, 13008.

[0143] [1] Preparation of the resist composition

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

[0145] 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.

[0146] [Table 1]

[0147]

[0148] In Table 1, component A is a metal complex, component B is a photoacid generator, and component C is a free radical scavenger. The structures of the metal complexes (M-1) to (M-2) used as component A are as described above. Detailed descriptions of components B and C are as follows.

[0149] P-1: Triphenylsulfonium p-toluenesulfonate

[0150] Sc-1: Butylated hydroxytoluene

[0151] In Table 1, PGMEA is propylene glycol monomethyl ether acetate.

[0152] 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 described below.

[0153] [Chemistry 21]

[0154]

[0155] [2] Evaluation of EB lithography

[0156] [Examples 2-1 to 2-4, Comparative Example 2-1]

[0157] Each resist composition (R-1~R-4, CR-1) was spin-coated onto a Si substrate with a 60 nm thick antireflective film DUV-42 (manufactured by Nikkei Co., Ltd.). A 40 nm thick resist film was obtained by pre-baking at 100°C for 60 seconds using a heated plate. The resist film was then exposed using an ELIONIX EB painting apparatus (ELS-F125, accelerating voltage 125 kV). PEB was applied to the heated plate at the temperatures shown in Table 2 for 60 seconds, followed by development for 30 seconds using 2-heptanone as the developer, thereby forming a pattern. The result was a negative line and pitch (LS) pattern with a width of 20 nm and a pitch of 40 nm. Sensitivity, LWR, and limiting resolution were evaluated for the obtained LS pattern using the methods described below. The results are shown in Table 2.

[0158] [Sensitivity Evaluation]

[0159] By observing the aforementioned LS pattern with an electron microscope, the optimal exposure value Eop (μC / cm) was determined to obtain an LS pattern with a spacing width of 20 nm and a pitch of 40 nm. 2 ), to make it a sensitivity.

[0160] [LWR Evaluation]

[0161] The dimensions of 10 points on an LS pattern obtained by exposure to the optimal amount of light along the length of the pitch width were measured using a CD-SEM (CG-5000) manufactured by Hitachi Advanced Technology Co., Ltd. The standard deviation (σ) was calculated as three times the value of the standard deviation (σ) (3σ), and this value was set as LWR. The smaller this value is, the more uniform and less rough the pitch width pattern can be obtained.

[0162] [Limited Resolution Evaluation]

[0163] Using a Hitachi Advanced Technology Co., Ltd. critical dimension SEM (CG-6300), the limit linewidth (nm) that can be resolved when forming a pattern by gradually increasing the exposure amount from the optimal exposure amount is determined, and this value is set as the limit resolution (nm). The smaller this value, the better the limit resolution, and the finer the pattern can be formed.

[0164] [Stability Evaluation After Exposure]

[0165] After exposure at the optimal exposure level, PEB and development were performed under the aforementioned conditions. Wafers patterned by developing immediately after PEB fabrication (PPD0h) and wafers patterned by developing 6 hours after PEB fabrication (PPD6h) were also produced. The linewidths of these wafers were determined using a Hitachi Advanced Technology Co., Ltd. critical dimension SEM (CG-6300), and the linewidth (CD) change (ΔPPD) due to post-exposure placement was calculated. The results are shown in Table 2.

[0166] [Table 2]

[0167]

[0168] As shown in Table 2, the resist compositions R-1 to R-4 of the present invention exhibit excellent LWR and limiting resolution in negative pattern formation using organic solvent development in EB lithography. Furthermore, it was confirmed that even after exposure and storage, CD changes are minimal, and the pattern remains stable after formation. Moreover, the resist compositions of the present invention possess a high density of zinc atoms with high EUV light absorption capacity, thus promising considerably high sensitivity in EUV lithography.

[0169] In contrast, it was found that the resist composition CR-1 used in negative patterning with organic solvent development using EB lithography exhibited poor LWR and limiting resolution. Furthermore, it was confirmed that CD changes were significant even after exposure and the pattern was unstable after formation.

[0170] [3] Evaluation of preservation stability

[0171] [Examples 3-1~3-4, Comparative Example 3-1]

[0172] At room temperature (20±5℃), each resist composition (R-1~R-4, CR-1) was placed for a specific period, and the presence or absence of precipitation was visually confirmed. Those that could be stored for more than 6 months without precipitation were rated as 0, and those that produced precipitation within 6 months were rated as ×. The results are shown in Table 3.

[0173] [Table 3]

[0174]

[0175] As shown in Table 3, the resist compositions R-1 to R-4 of the present invention exhibit excellent storage stability, indicating good operability.

[0176] In contrast, the resist composition CR-1 showed poor storage stability, indicating poor operability.

[0177] Furthermore, this invention is not limited to the embodiments described above. The embodiments described above are examples, and those having a structure that is substantially the same as the technical concept described in the claims of this invention and performing the same effect are all intended to be included within the scope of this invention.

[0178] Explanation of reference numerals in the attached figures

[0179] 1: Resist film

[0180] 2: Underlayer film of resist

[0181] 3:Substrate

[0182] 10: Layered bodies

Claims

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 hydrocarbylcarbonyl group having a carbon number of 1 to 20, or a hydrocarbyl group having a carbon number of 1 to 20 which can also contain a hetero atom; and X is a halogen atom or a hydrocarbyl group having a carbon number of 1 to 20 which can also contain a hetero atom.

2. A laminate characterized by comprising: Possessing: A substrate, and A resist film obtained from the resist composition according to claim 1 on the substrate.

3. The laminate according to claim 2, wherein A resist underlayer film is further provided between the substrate and the resist film.

4. A pattern forming process characterized by, Comprising the steps of: Forming a resist film on a substrate, or on a resist underlayer film of a substrate on which a resist underlayer film is laminated, using the resist composition according to claim 1, Exposing the resist film to high-energy rays, and Developing the exposed resist film using a developer.

5. The pattern forming process according to claim 4, wherein An electron beam or extreme ultraviolet rays is used as the high-energy rays.

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