Compound, method for producing said compound, photosensitive composition containing said compound, and pattern forming method, substrate, and method for producing substrate using said composition

Abstract

Provided are a transition metal cluster compound capable of enabling miniaturization of a circuit pattern, and a photosensitive composition containing the same.　This transition metal cluster compound contains transition metal atoms and carboxylate ligands A, and is characterized in that: the carboxylate ligands A have an alicyclic structure to which carboxylate groups are bonded; in the alicyclic structure, carbons bonded to the carboxylate groups are quaternary carbon; and the transition metal cluster compound may contain oxygen and / or a hydroxyl group.

Description

Compound, method for producing the compound, photosensitive composition containing the compound, pattern forming method using the composition, substrate, and method for producing the substrate

[0001] The present invention relates to a transition metal cluster compound suitable for use in ultra-microlithography processes such as the manufacture of ultra-LSIs and high-capacity microchips, as well as other photofabrication processes, a method for producing the compound, a photosensitive composition containing the compound, a pattern formation method using the photosensitive composition, a substrate, and a method for producing the substrate.

[0002] In the semiconductor device manufacturing process, microfabrication is performed using lithography with photoresist compositions. In semiconductor photolithography, circuit patterns become smaller as semiconductor devices become smaller, according to Moore's Law, and further miniaturization is desired. The advancement of photolithography can be broadly attributed to the shortening of wavelengths of light sources used in exposure tools and the associated development of new photoresists. Photoresists are required to satisfy all of the following requirements: high resolution, low roughness, and high sensitivity. Conventional resists are photosensitive compositions containing organic polymer-based photoacid generators and are called chemically amplified resists. This resist promotes chemical reactions through the diffusion of acid. However, the acid diffusion process can cause line edge roughness (LER), resulting in reduced resolution, making them incompatible with ultrafine patterning.

[0003] In recent years, non-chemically amplified photoresists (hereinafter referred to as metal-containing resists) have been proposed, which are primarily composed of compounds containing metal elements such as Zn and Sn. In metal-containing resists, the metal component itself is the photosensitive substance and functions as the base material. Because they do not involve acid diffusion, they can improve line edge roughness, making them promising next-generation resist materials for forming finer pattern structures. In fact, it has been reported that finer patterns can be formed using next-generation exposure equipment using extreme ultraviolet (EUV) light.

[0004] For example, Patent Documents 1 to 5 and Non-Patent Documents 1 to 3 listed below disclose methods of forming resist patterns using extreme ultraviolet rays (EUV light) or electron beams.

[0005] JP 2015-108781 A JP 2001-072716 A JP 2017-173537 A JP 2012-185484 A JP 2021-102604 A

[0006] Minoru Toriumi etc.,Proc.SPIE,9779(2016)97790GLianjia Wu etc.,Proc.SPIE,10957(2019)109570BNeha Thakur etc.,Proc.SPIE,10957(2019)10957D

[0007] In photolithography, particularly in semiconductor photolithography, organic resist materials tend to have poor absorption of EUV and not achieve high sensitivity, and there is a demand for photosensitive compositions and pattern formation methods that can realize even finer circuit patterns.

[0008] As a result of extensive research, the present inventors have found that compounds having a specific structure are suitable for photoresists compatible with ultrafine patterns. Accordingly, an object of the present invention is to provide a transition metal cluster compound capable of forming a negative pattern with high sensitivity to EUV exposure, a photosensitive composition containing the same, a pattern formation method using the photosensitive composition, a substrate using the pattern formation method, and a method for manufacturing a substrate.

[0009] The present invention has the following aspects [1] to

[21] .

[0010] [1] A transition metal cluster compound comprising a transition metal atom and a carboxylate ligand A, wherein the carboxylate ligand A has an alicyclic structure bonded to a carboxylate group, and the carbon in the alicyclic structure bonded to the carboxylate group is a quaternary carbon and may contain oxygen and / or a hydroxyl group.

[0011] [2] The transition metal cluster compound according to [1], wherein the alicyclic structure is a 3- to 8-membered ring.

[0012] [3] The transition metal cluster compound according to [1] or [2], which has a substituent R on the quaternary carbon to which the carboxylate group is bonded, and the substituent R is an organic group or a halogen atom.

[0013] [4] The transition metal cluster compound according to [3], wherein the organic group is any one of a hydrocarbon group, an ester group, a sulfonyl group, an alkoxy group, an amide group, an amino group, and a carbonyl oxygen group.

[0014] [5] The transition metal cluster compound according to [3] or [4], wherein the substituent R is an organic group having 1 to 10 carbon atoms.

[0015] [6] The transition metal cluster compound according to any one of [1] to [5], wherein the alicyclic structure to which the carboxylate group is bonded is a cycloalkyl group.

[0016] [7] The transition metal cluster compound according to any one of [1] to [6], wherein the carboxylate ligand A is represented by the following general formula B-1:

[0017]

[0018] In the above general formula B-1, the substituent R is an organic group or a halogen atom. Ａ are each independently a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms, and the substituent R Ａ may be the same or different, and n is an integer of 1 to 6.

[0019] [8] The transition metal cluster compound according to any one of [1] to [3], wherein the alicyclic structure is a cycloalkenyl group.

[0020] [9] The transition metal cluster compound according to any one of [1] to [8], wherein the carboxylate ligand A is at least one selected from the groups represented by the following general formulas C-1 to C-12:

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033] In the above general formulas C-1 to C-12, the substituent R is an organic group or a halogen atom. １ ~R １００ are each independently a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms. １ ~R １００ may be the same or different.

[0034]

[10] The transition metal cluster compound according to any one of [1] to [9], wherein the transition metal atom is selected from the group consisting of zirconium, hafnium, and titanium.

[0035]

[11] The transition metal cluster compound according to any one of [1] to

[10] , wherein the quaternary carbon in the alicyclic structure to which the carboxylate group is bonded has a substituent R, the substituent R being an organic group or a halogen atom, and another carbon in the alicyclic structure is bonded to any one of a hydrogen atom, a halogen atom, and an organic group having 1 to 20 carbon atoms.

[0036]

[12] The transition metal cluster compound according to any one of [1] to

[11] , wherein the transition metal cluster compound is electrically neutral.

[0037]

[13] A method for producing a transition metal cluster compound according to any one of [1] to

[12] , comprising a step of reacting a solution containing the transition metal atoms with a carboxylic acid having the structure of the carboxylate ligand A.

[0038]

[14] A photosensitive composition comprising the transition metal cluster compound according to any one of [1] to

[12] .

[0039]

[15] The photosensitive composition according to

[14] , further comprising a solvent.

[0040]

[16] A photosensitive composition comprising the transition metal cluster compound according to any one of [1] to

[12] in a concentration of 50 to 100 mass % of the total solids.

[0041]

[17] The photosensitive composition according to any one of

[14] to

[16] , which reacts with actinic radiation having a wavelength of 6 nm to 15 nm.

[0042]

[18] A pattern forming method comprising the steps of applying the photosensitive composition according to any one of

[14] to

[17] to a substrate, exposing the applied photosensitive composition to actinic radiation, and developing the exposed photosensitive composition using a developer.

[0043]

[19] The pattern formation method according to

[18] , wherein the development is carried out using a developer, and the developer is an organic solvent having a solubility parameter (SP value) of 7.5 to 11.

[0044]

[20] A substrate having a patterned layer obtained by the pattern forming method according to

[18] or

[19] .

[0045]

[21] A method for producing a substrate having a patterned layer obtained by the pattern forming method according to

[18] or

[19] .

[0046] The transition metal cluster compound of the present invention has an alicyclic structure bonded to a carboxylate group, and contains a carboxylate ligand A in which the carbon in the alicyclic structure bonded to the carboxylate group is a quaternary carbon. Therefore, it is thought that the carboxylate moiety reacts with actinic radiation such as electron beam (EB) irradiation or extreme ultraviolet (EUV) exposure, becoming insoluble in organic solvents, thereby forming a negative pattern and resulting in a compound with excellent exposure sensitivity. Detailed Description of the Invention

[0047] The present invention will be described below based on one embodiment, but the present invention is not limited to this embodiment.

[0048] In addition, in this specification, there are some descriptions using "~" as a description expression to indicate a numerical range from a lower limit value to an upper limit value of a numerical value, but the numerical range in this description is a numerical range specified as being equal to or greater than the lower limit value and equal to or less than the upper limit value, including the lower limit value itself and the upper limit value itself.

[0049] [Transition Metal Cluster Compound] A transition metal cluster compound according to one embodiment of the present invention (hereinafter also referred to as the present cluster compound) is a transition metal cluster compound comprising a transition metal atom and a carboxylate ligand A, wherein the carboxylate ligand A has an alicyclic structure bonded to a carboxylate group, and the carbon in the alicyclic structure bonded to the carboxylate group is a quaternary carbon, and may contain oxygen and / or a hydroxyl group.

[0050] The term "cluster compound" used herein refers to a metal complex molecule having a metal atom and a ligand, in which one or more metal atoms are bonded to each other directly or through a bridging ligand, including polynuclear complexes. The cluster compound may contain oxygen and / or hydroxyl groups within its structure, preferably a μ-oxo ligand (—O—) in which an oxygen atom is coordinated between metal atoms and / or a μ-hydroxy ligand (—OH) in which a hydroxy group is coordinated to a metal. The term "cluster compound" used herein refers to a compound having multiple metal atoms, including those in which the metal atoms are bonded to each other via a metal-metal bond or those in which the metal atoms are bonded with one to three atoms apart. The term "carboxylate ligand" refers to a ligand having at least one carboxylate group, and a carboxylate group is a functional group having the chemical structure -C(═O)O-. To more effectively achieve the effects of the present invention, a ligand having only one carboxylate group is preferred.

[0051] The present cluster compound contains a transition metal atom, and examples of the transition metal atom include zinc, cadmium, gold, silver, copper, platinum, palladium, nickel, iridium, rhodium, cobalt, osmium, ruthenium, iron, rhenium, manganese, tungsten, molybdenum, chromium, tantalum, zirconium, hafnium, titanium, yttrium, and scandium. The metal of the present cluster compound is preferably one or more selected from these, and among these, zirconium, hafnium, or titanium is preferred. Hafnium is an element of the same group as zirconium and has very similar chemical and physical properties.

[0052] To enhance solubility in solvents, the cluster compound preferably contains two or more metal atoms, more preferably three or more. More specifically, the cluster compound preferably contains two to twenty, two to six, four to six, or five to six, with six being particularly preferred. In the case of a mixture, the cluster compound preferably contains the most cluster structural components with six metal atoms. The cluster compound is preferably electrically neutral, and the number of metal atoms is preferably set to ensure an electrically neutral state. In other words, the cluster compound is preferably not a cation or anion. Note that it may not be possible to clearly distinguish whether the cluster compound has a single complex structure or cluster structure, or whether it is a mixture of complex structures or cluster structures with different numbers of metal atoms. Even in such cases, compounds satisfying the above-mentioned number of metal atoms are included in the cluster compound.

[0053] The cluster compound includes a carboxylate ligand A, which has an alicyclic structure to which a carboxylate group is bonded, and the carbon to which the carboxylate group is bonded is a quaternary carbon among the carbons constituting the alicyclic structure. The alicyclic structure of the carboxylate ligand A is preferably a 3- to 8-membered ring, and more preferably a 3- to 6-membered ring. The alicyclic structure may be composed of a saturated hydrocarbon or may contain a double bond, and examples thereof include a cycloalkyl group or a cycloalkenyl group. In the case of a cycloalkenyl group, the position of the double bond is not particularly limited. More specifically, when the alicyclic structure is a cycloalkyl group, examples include a cyclopropanoyl group, a cyclobutanoyl group, a cyclopentenoyl group, a cyclohexenoyl group, a cycloheptenoyl group, and a cyclooctenoyl group. Preferred are a cyclopropanoyl group, a cyclobutanoyl group, a cyclopentenoyl group, and a cyclohexenoyl group. Examples of cycloalkenyl groups include cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, and cyclooctenyl groups, with cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl groups being preferred.

[0054] The carbon atom to which the carboxylate group in the alicyclic structure of the carboxylate ligand A is bonded is a quaternary carbon. It is preferable that a substituent R be bonded to this quaternary carbon. The substituent R is an organic group or a halogen atom. Such an organic group may contain a halogen atom or a heteroatom. Examples of the organic group include hydrocarbon groups, such as linear alkyl groups such as methyl and ethyl groups, branched alkyl groups such as isopropyl and butyl groups, halogenated alkyl groups such as halogenated methyl groups, halogenated ethyl groups, and halogenated propyl groups, cycloalkyl groups such as cyclopropyl and cyclobutyl groups, aryl groups such as phenyl and naphthyl groups, arylalkyl groups, and alkylaryl groups. Examples of organic groups containing a heteroatom include ester groups, sulfonyl groups, alkoxy groups, amide groups, amino groups, and carbonyl oxygen groups. Examples of ester groups include alkyl ester groups such as acetyl groups, ethyl ester groups, and n-propyl ester groups, and aromatic ester groups such as phenyl ester groups. Examples of sulfonyl groups include methylsulfonyl groups, ethylsulfonyl groups, and n-propylsulfonyl groups. Examples of alkoxy groups include alkoxyalkyl groups such as alkoxymethyl groups, alkoxyethyl groups, and alkoxypropyl groups. Examples of amino groups include aminoalkyl groups such as amino group (-NH), aminomethyl group (NH-CH-), aminoethyl group (NH-C-H-), and aminopropyl group (NH-C-H-), and dialkylamino groups such as dimethylamino ((CH)N-) and diethylamino ((C-H)N-). Examples of amide groups include alkylamide groups such as methylamide group ((CH)N(C=O)-) and ethylamide group ((C-H)N(C=O)-). Examples of carbonyl oxygen groups (>C=O) include halogen atoms such as fluorine, chlorine, and bromine. The substituent R preferably has 1 to 10 carbon atoms, more preferably 1 to 7, and particularly preferably 1 to 5. In terms of film formability, exposure sensitivity, and solvent solubility, the substituent R is preferably a hydrocarbon group, more preferably a saturated hydrocarbon group, and particularly preferably an alkyl group.The heteroatom or halogen atom that may be contained in the organic group includes oxygen, nitrogen, phosphorus, sulfur, silicon, chlorine, bromine, iodine, and the like.

[0055] In the present cluster compound, the carbon atom bonded to a carboxylate group refers to the carbon atom bonded to the carbonyl carbon of the carboxylate group. This carbon atom is preferably a carbon atom constituting the cyclic structure of the alicyclic structure, and the carbon atom constituting the cyclic structure of the alicyclic structure is preferably directly bonded to the carbonyl carbon of the carboxylate group.

[0056] More specifically, the carboxylate ligand A is preferably one in which, among the carbon atoms constituting the cyclic structure of the alicyclic structure, the carbon atom to which the carboxylate group is bonded further bonds the substituent R, and another carbon atom constituting the cyclic structure is bonded to any of a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms. More preferably, another carbon atom constituting the cyclic structure is bonded to any of a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an amino group having 1 to 20 carbon atoms. Examples include those represented by the following general formula B-1 or general formulae C-1 to C-12.

[0057]

[0058] In the above general formula B-1, the substituent R is an organic group or a halogen atom. Specific examples and preferred embodiments of the substituent R are the same as those of the above substituent R. Ａ is a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms. Ａ may be independently the same or different. n is an integer of 1 to 6, preferably 1 to 3. However, from the viewpoint of reactivity, the substituent R and any of the substituents R Ａ Preferably, the substituent R does not form a saturated polycyclic structure by linking with each other. Such an organic group may contain a halogen atom or a heteroatom. ＡSpecific examples of the organic group or halogen atom in the substituent R include the same as those of the substituent R. Preferred examples of the organic group include hydrocarbon groups, alkoxy groups, and amino groups. Ａ The organic group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and particularly preferably 1 to 5 carbon atoms. Ａ is preferably a hydrogen atom, a halogen atom, a hydrocarbon group, an alkoxy group, or an amino group, more preferably a hydrogen atom or a hydrocarbon group, and even more preferably a hydrogen atom. Ａ More preferably, it is any one of a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an amino group having 1 to 20 carbon atoms. Even more preferably, it is any one of a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and an amino group having 1 to 10 carbon atoms. Particularly preferably, it is any one of a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and an amino group having 1 to 5 carbon atoms, and among these, it is any one of a hydrogen atom and a hydrocarbon group having 1 to 5 carbon atoms. A hydrogen atom is most preferred.

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] In the general formulas C-1 to C-12, the substituent R is an organic group or a halogen atom. Specific examples and preferred embodiments of the substituent R are the same as those of the above-mentioned substituent R. １ ~R １００ are each independently a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms. １ ~R １００ may be the same or different. Such organic groups may contain halogen atoms or heteroatoms. １ ~R １００ Specific examples of the organic group or halogen atom of the substituent R include the same as those of the substituent R. １ ~R １００ When the substituent R is an organic group, the number of carbon atoms is more preferably 1 to 10, and particularly preferably 1 to 6. １ ~R １００ When the substituent R is an organic group, it is preferably a hydrocarbon group, an alkoxy group, or an amino group. １ ~R １００ are preferably each independently any one of a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an amino group having 1 to 20 carbon atoms. More preferably, they are any one of a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and an amino group having 1 to 10 carbon atoms. Even more preferably, they are any one of a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an amino group having 1 to 6 carbon atoms. Particularly preferably, they are any one of a hydrogen atom and a hydrocarbon group having 1 to 6 carbon atoms. Most preferably, they are a hydrogen atom. However, from the viewpoint of reactivity, in each general formula, the substituent R and any one of the substituents R １ ~R １００ Preferably, the groups do not link together to form a saturated polycyclic structure.

[0072] The structure of the carboxylate ligand A can be analyzed by known techniques, for example, by NMR.

[0073] The molecular weight of the cluster compound is preferably 100 to 8,000, more preferably 500 to 6,000, and particularly preferably 1,000 to 5,000. If the molecular weight of the cluster compound is below the upper limit, the volume is small, and therefore roughness and resolution are expected to be improved. On the other hand, if the molecular weight is above the lower limit, coating properties and etching resistance tend to be improved. Note that this molecular weight is a guideline and does not determine lithography properties by itself, so it is not limited to this. The molecular weight of the cluster compound can be analyzed by known techniques, for example, mass spectrometry.

[0074] [Production Method] The present cluster compound can be produced, for example, by reacting a compound containing a transition metal atom with a carboxylic acid having a structure of carboxylate ligand A in a solution. As an example, the present cluster compound can be produced by reacting a solution containing a compound containing a transition metal atom with a carboxylic acid having a structure of carboxylate ligand A.

[0075] Examples of compounds containing a transition metal atom include compounds containing a transition metal atom such as zirconium, hafnium, or titanium, and specific examples include transition metal alkoxides and transition metal chloride compounds. Examples of transition metal alkoxide compounds include zirconium methoxide, zirconium ethoxide, zirconium n-propoxide, zirconium isopropoxide, zirconium n-butoxide, zirconium t-butoxide, and zirconium 2-ethylhexoxide. Examples of transition metal chloride compounds include zirconium chloride, zirconium oxychloride, and hydrates thereof.

[0076] Examples of carboxylic acids having a structure of carboxylate ligand A include the following carbonyl compounds having a cyclic structure with one double bond, in which a substituent is bonded to the quaternary carbon bonded to the carboxylate group.

[0077]

[0078] As the carboxylic acid having a structure of a carboxylate ligand A, for example, a carboxylic acid having a structure represented by the above general formula (B-1) or general formulas (C-1) to (C-12) can be used, and more specific examples include 1-methyl-3-cyclohexene-1-carboxylic acid, 1-ethyl-3-cyclohexene-1-carboxylic acid, 1-propyl-3-cyclohexene-1-carboxylic acid, etc.

[0079] To explain the production method in more detail, the method can be carried out by placing a solution containing a compound containing a transition metal atom and a carboxylic acid having a structure of carboxylate ligand A in a reaction vessel and stirring them. A solvent may be added to dissolve the raw materials.

[0080] The reaction temperature is preferably room temperature to 150°C, more preferably room temperature to 120°C, from the viewpoint of completing the reaction and preventing undesirable side reactions. The reaction time is preferably 1 to 100 hours, more preferably 3 to 24 hours. If the product precipitates or crystallizes after the reaction, it can be filtered to obtain the cluster compound. The post-reaction solution may be cooled to -30°C to 20°C to obtain the product precipitate or crystallization. If no product precipitate is observed after the reaction, the target product can be recovered by distilling off the solvent by applying reduced pressure to the reaction vessel. Alternatively, the product can be reprecipitated by contacting the reaction solution with a poor solvent. A sealed reaction vessel is preferred, and for small volumes, a Schlenk tube or the like can be used. The reaction is preferably carried out under a nitrogen or argon atmosphere. A flask equipped with a reflux condenser is preferred as the reaction vessel, and when heated, the reaction is preferably carried out under a nitrogen or argon atmosphere.

[0081] The solution containing the compound containing a transition metal atom and the carboxylic acid having a structure of carboxylate ligand A are preferably mixed in a substance amount ratio of 1:2 to 1:10, more preferably 1:2 to 1:4.

[0082] [Photosensitive Composition] A photosensitive composition according to one embodiment of the present invention (hereinafter also referred to as the present photosensitive composition) contains the present cluster compound. The present photosensitive composition may contain only one type of the present cluster compound, or may contain two or more types of the present cluster compound.

[0083] The content of the cluster compound in the photosensitive composition is 50% by mass or more and 100% by mass or less, preferably 60 to 100% by mass or more, and particularly preferably 70 to 90% by mass or less, of the total solids of the photosensitive composition relative to the total of all components other than the solvent. The total solids refer to the solid obtained by evaporating the photosensitive composition to dryness, for example. The concentration of the cluster compound in the photosensitive composition is preferably 0.1% by mass or more and 70% by mass or less, more preferably 0.5% by mass or more and 50% by mass or less, and particularly preferably 1% by mass or more and 40% by mass or less. When the content of the cluster compound in the photosensitive composition is equal to or greater than the above-mentioned lower limit, good exposure sensitivity can be obtained.

[0084] [Photoacid Generator] The photosensitive composition can also function by containing, together with the cluster compound, a photoacid generator that generates an acid when exposed to actinic radiation. Examples of actinic radiation include the bright line spectrum of a mercury lamp, far ultraviolet radiation represented by an excimer laser, extreme ultraviolet radiation (EUV light), X-rays, and electron beams. From the viewpoint of resolution, a shorter exposure wavelength is preferred, and extreme ultraviolet radiation (EUV light) emitting light with a wavelength of 6 nm to 15 nm is preferred.

[0085] The photoacid generator that generates an acid when exposed to actinic radiation is not particularly limited as long as it is a known compound, but is preferably a compound that generates an organic acid, such as at least one of sulfonic acid, bis(alkylsulfonyl)imide, and tris(alkylsulfonyl)methide, when exposed to actinic radiation.

[0086] The photoacid generators can be used alone or in combination of two or more. When two or more types are used in combination, preferred embodiments include (1) the use of two photoacid generators with different acid strengths, and (2) the use of two photoacid generators with different sizes (molecular weights or carbon numbers) of the acids they generate. Examples of the embodiment (1) include the use of a fluorine-containing sulfonic acid generator and a tris(fluoroalkylsulfonyl)methide acid generator, a fluorine-containing sulfonic acid generator and a non-fluorine-containing sulfonic acid generator, and an alkylsulfonic acid generator and an arylsulfonic acid generator. Examples of the embodiment (2) include the use of two photoacid generators whose acid anions differ in the number of carbon atoms by four or more.

[0087] In particular, the present photosensitive composition is preferably a photosensitive composition for use with actinic radiation. A photosensitive composition that reacts with actinic radiation is preferred because its development speed in a developer changes, allowing a pattern to be formed after a certain period of development. As actinic radiation, a shorter wavelength is preferred because higher resolution can be obtained, and actinic radiation with a wavelength of 6 nm to 15 nm is preferred, and more preferably actinic radiation with a wavelength of 6.5 nm to 13.5 nm is preferred. In other words, extreme ultraviolet (EUV) light is preferred. In other words, the present photosensitive composition is preferably a photosensitive composition that reacts with actinic radiation with a wavelength of 6 nm to 15 nm. "Reaction" refers to the photosensitive composition absorbing the irradiated actinic radiation and then being modified by the generated active species, such as radicals and ions.

[0088] The present cluster compound reacts with light even when used alone in a photosensitive composition. Adding a photoacid generator synergistically enhances the photosensitivity of the present cluster compound in the photosensitive composition. Therefore, adding a photoacid generator is preferable when a photosensitive composition composed solely of the present cluster compound does not have sufficient photosensitivity for the required specifications. When the present photosensitive composition contains a photoacid generator, the content of the photoacid generator in the present photosensitive composition (the total amount when multiple photoacid generators are used) is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, and even more preferably 1 to 15% by mass, based on the total components of the photosensitive composition other than the solvent. When the content of the photoacid generator in the photosensitive composition is equal to or greater than the lower limit, the photosensitivity is enhanced. When the content is equal to or less than the upper limit, the composition is less susceptible to the poor film-forming properties of the photoacid generator, resulting in good film-forming properties based on the photosensitive compound of the present invention.

[0089] [Solvent] The present photosensitive composition usually contains a solvent for preparing the composition. The solvent for preparing the photosensitive composition is not particularly limited as long as it dissolves each component, and examples thereof include toluene, alkylene glycol monoalkyl ether carboxylates (such as propylene glycol monomethyl ether acetate (PGMEA), which is 1-methoxy-2-acetoxypropane), alkylene glycol monoalkyl ethers (such as propylene glycol monomethyl ether (PGME; 1-methoxy-2-propanol)), alkyl lactate esters (such as ethyl lactate and methyl lactate), cyclic lactones (such as γ-butyrolactone, preferably having 4 to 10 carbon atoms), linear or cyclic ketones (such as 2-heptanone and cyclohexanone, preferably having 4 to 10 carbon atoms), alkylene carbonates (such as ethylene carbonate and propylene carbonate), alkyl carboxylates (preferably alkyl acetates such as butyl acetate), alkyl alkoxyacetates (ethyl ethoxypropionate), alkylamides (N,N-dimethylformamide), and alkyl sulfoxides (dimethyl sulfoxide). Other usable solvents include, for example, the solvents described in paragraphs

[0244] and after of US Patent Application Publication No. 2008 / 0248425A1.

[0090] Of the above, toluene, PGMEA, ethyl lactate, cyclohexanone, 2-heptanone, N,N-dimethylformamide, dimethyl sulfoxide, alkylene glycol monoalkyl ether carboxylate, and alkylene glycol monoalkyl ether are preferred.

[0091] These solvents may be used alone or in combination of two or more. When two or more solvents are mixed, it is preferable to mix a solvent having a hydroxyl group with a solvent not having a hydroxyl group. As the solvent having a hydroxyl group, alkylene glycol monoalkyl ether is preferred, and as the solvent not having a hydroxyl group, alkylene glycol monoalkyl ether carboxylate, N,N-dimethylformamide, and dimethyl sulfoxide are preferred.

[0092] The solvent for the present photosensitive composition preferably has a solubility parameter (SP value) of 7.5 to 11, more preferably 8 to 11. The solubility parameter (SP value) will be described later.

[0093] The content of the solvent in the total amount of the photosensitive composition can be adjusted as appropriate depending on the film thickness of the pattern to be formed, etc., but is generally adjusted so that the total concentration of components other than the solvent in the photosensitive composition is 0.5 to 30 mass %, preferably 1.0 to 20 mass %, more preferably 1.5 to 10 mass %, and particularly preferably 1.5 to 5 mass %.

[0094] [Surfactant] The photosensitive composition preferably further contains a surfactant. The surfactant is preferably a fluorine-based and / or silicone-based surfactant. Examples of such surfactants include Megafac F176 and Megafac R08 manufactured by Dainippon Ink and Chemicals, Inc., PF656 and PF6320 manufactured by OMNOVA, Troisol S-366 manufactured by Troy Chemical Co., Ltd., Fluorad FC430 manufactured by Sumitomo 3M Limited, and Polysiloxane Polymer KP-341 manufactured by Shin-Etsu Chemical Co., Ltd. Surfactants other than fluorine-based and / or silicone-based surfactants can also be used. More specifically, examples include polyoxyethylene alkyl ethers and polyoxyethylene alkylaryl ethers.

[0095] Other known surfactants may also be used as appropriate, such as those described in U.S. Patent Application Publication No. 2008 / 0248425A1, paragraphs

[0273] and thereafter.

[0096] The surfactant may be used alone or in combination of two or more kinds. The content of the surfactant is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total mass of the components other than the solvent in the photosensitive composition.

[0097] [Resin] The photosensitive composition can be used alone to form a pattern, but it may also contain a resin material in addition to the cluster compound. Resin materials are not particularly limited as long as they are soluble in a solvent, and examples include novolac resins, styrene resins, and acrylic resins. They may be used alone or in combination of two or more types. Their molecular structure may contain dissolution-inhibiting groups that decompose in the presence of chemically active species such as acids or radicals, or crosslinking groups that crosslink, or they may be copolymer resins of two or more types. Examples of dissolution-inhibiting groups that decompose in the presence of chemically active species such as acids or radicals include alkoxycarbonyl groups and acetal groups. Examples of crosslinking groups that crosslink in the presence of chemically active species such as acids or radicals include vinyl groups, carbodiimide groups, N-hydroxyester groups, imide ester groups, maleimide groups, haloacetyl groups, pyridyl disulfide groups, hydrazide groups, alkoxyamino groups, and diazirine groups.

[0098] [Other Additives] In addition to the components described above, the photosensitive composition may contain, as appropriate, carboxylic acids, carboxylic acid onium salts, dissolution-inhibiting compounds with a molecular weight of 3,000 or less as described in, for example, Proceedings of SPIE, 2724, 355 (1996), dyes, plasticizers, photosensitizers, light absorbers, crosslinking agents, antioxidants, and the like. Carboxylic acids are particularly preferred for improving performance. Preferred carboxylic acids include aromatic carboxylic acids such as benzoic acid and naphthoic acid. The carboxylic acid content is preferably 0.01 to 10% by mass, more preferably 0.01 to 5% by mass, and even more preferably 0.01 to 3% by mass, based on the total weight of the components of the photosensitive composition other than the solvent.

[0099] [Method for Producing the Photosensitive Composition] The photosensitive composition can be produced by dissolving the cluster compound, a photoacid generator (if used) and other components in a solvent for preparation, and filtering the solution through a filter, if necessary. The filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon, with a pore size of 0.2 μm or less, more preferably 0.1 μm or less, and even more preferably 0.05 μm or less.

[0100] [Pattern Forming Method] A pattern forming method according to one embodiment of the present invention (hereinafter also referred to as the present pattern forming method) comprises the steps of applying the present photosensitive composition to a substrate, exposing the applied photosensitive composition to actinic radiation, and developing the exposed photosensitive composition. More specifically, the steps comprise the steps of applying the present photosensitive composition to a substrate to form a photosensitive layer, irradiating predetermined regions of the photosensitive layer with actinic radiation to perform pattern exposure, and developing the exposed photosensitive layer to selectively remove exposed or unexposed regions of the photosensitive layer. The photosensitive layer forming step yields a substrate having a photosensitive layer. The pattern exposure step yields a substrate having a photosensitive layer with a latent image. The development step yields a substrate having a patterned layer.

[0101] [Photosensitive Layer Formation Step] The photosensitive layer can be formed by applying the photosensitive composition to a substrate (e.g., silicon or silicon dioxide coated) such as those used in the manufacture of integrated circuit devices using a suitable coating method such as a spinner, followed by drying at 50 to 150°C. In this case, a commercially available inorganic or organic antireflective film can be used, if necessary. Furthermore, an antireflective film can be applied as an underlayer of the resist.

[0102] [Exposure Step] In the present invention, unless otherwise specified, "exposure to actinic radiation" includes not only exposure with far ultraviolet light typified by mercury lamps and excimer lasers, X-rays, extreme ultraviolet light (EUV light), and the like, but also exposure with particle beams such as electron beams and ion beams. Exposure can be performed by irradiating predetermined regions of the formed photosensitive layer with actinic radiation through a predetermined mask to perform pattern exposure, or by irradiating with an electron beam to perform pattern exposure without using a mask (direct writing). The actinic radiation is not particularly limited, but examples include KrF excimer lasers, ArF excimer lasers, extreme ultraviolet light (EUV light), and electron beams. Extreme ultraviolet light (EUV light) and electron beams are preferred, and as described above, extreme ultraviolet light (EUV light) emitting actinic radiation with a wavelength of 6 nm to 15 nm is preferred.

[0103] After the exposure, baking (heating) may or may not be performed before development. When baking (heating) is performed, the heating temperature is preferably 50 to 200°C, more preferably 60 to 180°C, and even more preferably 80 to 150°C. When baking (heating) is performed, the heating time is preferably 30 to 300 seconds, more preferably 30 to 180 seconds, and even more preferably 30 to 90 seconds. Heating can be performed by means provided in a normal exposure / developing machine, and may be performed using a hot plate or the like.

[0104] [Development Step] After exposure, development is carried out to selectively remove the exposed or unexposed areas of the photosensitive layer. As the development method, a known method can be adopted, for example, a method using a gas or a method using a developer.

[0105] <Developer> It is preferable to use an organic solvent as the developer, and an organic solvent having a vapor pressure of 5 kPa or less at 20° C. is preferred, more preferably 3 kPa or less, and particularly preferably 2 kPa or less. By setting the vapor pressure of the organic solvent to 5 kPa or less, evaporation of the developer on the substrate or in the developing cup is suppressed, improving the temperature uniformity within the surface of the pattern-formed substrate, and as a result, improving the dimensional uniformity within the surface of the pattern-formed substrate.

[0106] As the organic solvent used as the developer, various organic solvents can be used, and for example, at least one solvent selected from ester-based solvents, ketone-based solvents, alcohol-based solvents, amide-based solvents, sulfoxide-based solvents, ether-based solvents, hydrocarbon-based solvents, and the like can be used.

[0107] Examples of ester-based solvents include alkyl carboxylate solvents such as methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, ethyl-3-ethoxypropionate, propylene glycol diacetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, and propyl lactate; alkylene glycol monoalkyl ether carboxylate solvents such as propylene glycol monomethyl ether acetate (PGMEA; also known as 1-methoxy-2-acetoxypropane), ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, and propylene glycol monoethyl ether acetate; and butyl acetate, amyl acetate, ethyl lactate, and propylene glycol monomethyl ether acetate are more preferred.

[0108] Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, isophorone, and propylene carbonate. Alkyl ketone solvents, such as methyl isobutyl ketone, methyl amyl ketone, cyclopentanone, cyclohexanone, and 2-heptanone, are more preferred.

[0109] Examples of alcohol-based solvents include alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol including 1-propanol or 2-propanol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, hexyl alcohols such as n-hexyl alcohol, heptyl alcohols such as n-heptyl alcohol, octyl alcohols such as n-octyl alcohol, and n-decanol; and glycols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, and 1,4-butylene glycol. alkylene glycol monoalkyl ether-based solvents such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether (PGME; also known as 1-methoxy-2-propanol), ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, and triethylene glycol monoethyl ether; glycol ether-based solvents such as methoxymethylbutanol and propylene glycol dimethyl ether; and phenol-based solvents such as phenol and cresol, with 1-hexanol, 2-hexanol, 1-octanol, 2-ethylhexanol, propylene glycol monomethyl ether, and cresol being more preferred.

[0110] Examples of the amide solvent that can be used include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphoric triamide, 1,3-dimethyl-2-imidazolidinone, etc. Examples of the sulfoxide solvent that can be used include dimethyl sulfoxide, etc.

[0111] Examples of the ether solvent include the alkylene glycol monoalkyl ether solvents and glycol ether solvents described above, as well as dioxane, tetrahydrofuran, tetrahydropyran, and the like.

[0112] Examples of hydrocarbon solvents include aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic hydrocarbon solvents such as pentane, hexane, octane, decane, and dodecane.

[0113] The developer preferably contains one or more solvents selected from alkylene glycol monoalkyl ether carboxylate solvents, alkylene glycol monoalkyl ether solvents, alkyl carboxylate solvents, and alkyl ketone solvents, and more preferably contains one or more solvents selected from dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, ethylene glycol, methyl alcohol, ethyl alcohol, 1-propanol, and 2-propanol.

[0114] As the developer, it is preferable to use a developer containing at least one organic solvent selected from the group consisting of ester solvents having no hydroxyl group in the molecule, ketone solvents having no hydroxyl group in the molecule, and ether solvents having no hydroxyl group in the molecule, amide solvents, and sulfoxide solvents.

[0115] The organic solvent used as the developer in the present invention is preferably an organic solvent having a solubility parameter (SP value) of 7.5 to 11. An organic solvent with a solubility parameter of 7.5 or more increases the development rate of the dissolved portion, while an organic solvent with a solubility parameter of 11 or less can suppress the development rate of the pattern formation portion, and is therefore preferred. The solubility parameter of the organic solvent of the developer is more preferably 8 to 11.

[0116] In the present invention, the solubility parameter (SP value) is calculated by the method proposed by Fedors et al. Specifically, the value is determined by referring to "POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol. 14, No. 2, ROBERT F. FEDORS. (pp. 147-154)." The SP value is a physical property determined by the content of hydrophobic and hydrophilic groups in the molecule, and when a mixed solvent is used, the SP value refers to the value of the mixture.

[0117] Examples of organic solvents that satisfy the above SP values ​​include diethylene glycol monomethyl ether (SP value = 10.7), triethylene glycol monomethyl ether (SP value = 10.7), ethylene glycol monoisopropyl ether (SP value = 10.9), ethylene glycol monobutyl ether (SP value = 10.2), diethylene glycol monobutyl ether (SP value = 10.0), triethylene glycol monobutyl ether (SP value = 10.0), ethylene glycol monoisobutyl ether (SP value = 9.1), ethylene glycol monohexyl ether (SP value = 9.9), diethylene glycol monohexyl ether (SP value = 9.7), diethylene glycol mono-2-ethylhexyl ether (SP value = 9.3), ethylene glycol monoallyl ether (SP value = 10.8), ethylene glycol monophenyl ether (SP value = 10.8), ethylene glycol monobenzyl ether (SP value = 10.9), propylene glycol monomethyl ether (SP value = 10.0), dipropylene glycol monomethyl ether (SP value = 10.0), and dipropylene glycol monomethyl ether (SP value = 10.0). propylene glycol monomethyl ether (SP value = 9.7), tripropylene glycol monomethyl ether (SP value = 9.4), propylene glycol monopropyl ether (SP value = 9.6), dipropylene glycol monopropyl ether (SP value = 9.8), propylene glycol monobutyl ether (SP value = 9.0), dipropylene glycol monobutyl ether (SP value = 9.6), ethylene glycol monomethyl ether acetate (SP value = 10.0), ethylene glycol monoethyl ether acetate ether acetate (SP value = 9.6), ethylene glycol monobutyl ether acetate (SP value = 8.9), diethylene glycol monoethyl ether acetate (SP value = 9.4), diethylene glycol monobutyl ether acetate (SP value = 9.0), propylene glycol monomethyl ether acetate (SP value = 9.4), propylene glycol monoethyl ether acetate (SP value = 9.0), and dipropylene glycol monomethyl ether acetate (SP value = 9.2).

[0118] The organic solvents may be used in combination with a plurality of solvents, or may be used in combination with other solvents or water. For example, as described in WO 2020 / 210660, at least two solvents each having a Hansen solubility parameter δH + δP of about 16 (J / cm ３ ) 1 / 2 or less, each independently having a sum of Hansen solubility parameters δH + δP of at least about 16 (J / cm ３ ) 1 / 2, it is also possible to use developer compositions that include from about 0.25% to about 45% by volume of one or more solvents.

[0119] The concentration of the organic solvent (total concentration when a plurality of organic solvents are mixed) in the developer is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. It is particularly preferred that the developer essentially consists of an organic solvent. The term "essentially consisting of an organic solvent" includes the case where the developer contains trace amounts of a surfactant, an antioxidant, a stabilizer, an antifoaming agent, etc.

[0120] The water content in the developer is preferably 10% by mass or less, more preferably 5% by mass or less, particularly preferably 3% by mass or less, and most preferably substantially no water. By keeping the water content at 10% by mass or less, good development characteristics can be obtained.

[0121] If necessary, an appropriate amount of a surfactant can be added to the developer used in the present invention. The surfactant may be the same as those described above as surfactants used in the photosensitive composition of the present invention. The amount of the surfactant used is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass, based on the total amount of the developer.

[0122] <Development Method> Examples of development methods that can be used include a method in which a substrate is immersed in a tank filled with a developer for a certain period of time (dip method), a method in which a developer is piled up on the surface of a substrate by surface tension and left standing for a certain period of time (puddle method), a method in which a developer is sprayed onto the surface of the substrate (spray method), and a method in which a developer is continuously dispensed onto a substrate rotating at a constant speed while a developer dispenser nozzle is scanned at a constant speed (dynamic dispense method). Furthermore, after the development step, a step of stopping development by replacing the solvent with another solvent may be carried out. The development time is preferably a time required for the cluster compound and the like in the photosensitive layer in the unexposed or exposed areas to be sufficiently dissolved, typically 10 to 300 seconds, more preferably 20 to 120 seconds. The temperature of the developer is preferably 0 to 50°C, more preferably 15 to 35°C. The amount of developer can be appropriately adjusted depending on the development method.

[0123] [Rinsing Step] The pattern forming method of the present invention may include, after the developing step, a step of washing with a rinse liquid containing an organic solvent.

[0124] <Rinse Liquid> The organic solvent used in the rinse liquid preferably has a vapor pressure of 0.05 kPa or more and 5 kPa or less, more preferably 0.1 kPa or more and 5 kPa or less, and most preferably 0.12 kPa or more and 3 kPa or less at 20° C. By adjusting the vapor pressure of the organic solvent used in the rinse liquid to 0.05 kPa or more and 5 kPa or less, the temperature uniformity within the wafer surface is improved, and further swelling due to penetration of the rinse liquid is suppressed, improving the dimensional uniformity within the wafer surface.

[0125] Various organic solvents can be used as the rinse solution. However, for the present cluster compound, it is preferable to use a rinse solution containing at least one organic solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents, or water. More preferably, after development, a cleaning step is performed using a rinse solution containing at least one organic solvent selected from ketone solvents, ester solvents, alcohol solvents, amide solvents, and hydrocarbon solvents. Even more preferably, after development, a cleaning step is performed using a rinse solution containing at least one organic solvent selected from the group consisting of alcohol solvents and hydrocarbon solvents. For example, as described in International Publication No. 2020 / 081483, a method can be used in which the rinse solution contains a quaternary ammonium hydroxide aqueous solution and the developer solution contains an organic solvent, or a method can be used in which the developer solution contains a quaternary ammonium hydroxide aqueous solution and the rinse solution contains an organic solvent. Specific examples of the ketone-based solvent, ester-based solvent, alcohol-based solvent, amide-based solvent, ether-based solvent, and hydrocarbon-based solvent used as the rinse solution are the same as those described above for the developer. Particularly preferably, a rinse solution containing at least one organic solvent selected from the group consisting of monohydric alcohol-based solvents, hydrocarbon-based solvents, and amide-based solvents is used.

[0126] Here, examples of the monohydric alcohol solvent used in the rinsing step after development include linear, branched, and cyclic monohydric alcohols. Specific examples include 1-butanol, 2-butanol, 3-methyl-1-butanol, tert-butyl alcohol, isopropyl alcohol, cyclopentanol, and cyclohexanol, with 1-butanol, 2-butanol, 3-methyl-1-butanol, and isopropyl alcohol being preferred. Examples of the hydrocarbon solvent include aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic hydrocarbon solvents such as octane, decane, and dodecane. Examples of the amide solvent include N,N-dimethylformamide.

[0127] The above-mentioned components may be mixed in plural, or may be mixed with an organic solvent other than those mentioned above.

[0128] The organic solvent may be mixed with water, but the water content in the rinse solution is usually 30% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less. Most preferably, the rinse solution does not contain water. By keeping the water content at 30% by mass or less, good development properties can be obtained.

[0129] The rinse solution may contain an appropriate amount of a surfactant, which may be the same as those used in the photosensitive composition described above, and the amount of surfactant used is usually 0.001 to 5 mass %, preferably 0.005 to 2 mass %, and more preferably 0.01 to 0.5 mass %, based on the total amount of the rinse solution.

[0130] <Rinsing Method> In the rinsing step, the developed pattern-formed substrate is washed with a rinse solution containing the organic solvent. The washing method is not particularly limited, but examples include a method in which the rinse solution is continuously applied to a substrate rotating at a constant speed (spin coating method), a method in which the substrate is immersed in a tank filled with the rinse solution for a certain period of time (dipping method), and a method in which the rinse solution is sprayed onto the substrate surface (spray method). Among these, the spin coating method is preferred for washing, and after washing, the substrate is rotated at a speed of 2000 to 4000 rpm to remove the rinse solution from the substrate. The substrate rotation time can be set depending on the rotation speed within a range that achieves removal of the rinse solution from the substrate, but is typically 10 seconds to 3 minutes. Rinsing is preferably performed at room temperature. The rinse time is preferably set so that no developing solvent remains on the substrate, typically 10 to 300 seconds, more preferably 20 to 120 seconds. The temperature of the rinse solution is preferably 0 to 50°C, and even more preferably 15 to 35°C. The amount of the rinse solution can be adjusted appropriately depending on the rinse method.

[0131] [Post-treatment Step] After the development treatment or rinsing treatment, a treatment can be performed using a supercritical fluid to remove the developer or rinsing solution adhering to the pattern. Furthermore, after the development treatment, rinsing treatment, or treatment with a supercritical fluid, a heat treatment can be performed to remove the solvent remaining in the pattern. The heating temperature and time are not particularly limited as long as a good resist pattern can be obtained, and are usually 40 to 160°C and 10 seconds to 3 minutes. The heat treatment may be performed multiple times.

[0132] [Uses] The photosensitive composition and the pattern forming method are suitable for use in producing semiconductor microcircuits, such as in the production of VLSIs and high-capacity microchips, and can produce substrates having patterned layers. During the production of semiconductor microcircuits, the patterned resist film is subjected to circuit formation and etching, and the remaining resist film portion is ultimately removed with a solvent or the like.

[0133] An example of the present invention will be described below. However, the present invention is not limited to this example. In the example, "%" is based on mass unless otherwise specified.

[0134] The following compounds 1 to 3 were synthesized to obtain Examples 1 to 3. The composition and ligand structure of each compound are as follows: １ The ratio of carboxylate ligands can be determined by NMR measurement.

[0135] [Synthesis of Carboxylic Acid 1 (1-ethyl-3-cyclohexene-1-carboxylic Acid)] Under a nitrogen atmosphere, a lithium diisopropylamide solution (Aldrich, 1M, THF / hexane solution, 309 mL, 0.309 mol) was placed in a reaction vessel and cooled to -30°C. 3-Cyclohexene-1-carboxylic acid (TCI, 17.0 g, 0.134 mol) was added, followed by hexamethylphosphoric triamide (TCI, 29.0 mL, 0.162 mol). The mixture was warmed to room temperature and stirred for 2 hours, producing a yellow solid. The reaction vessel was cooled to -30°C, and iodoethane (TCI, 14.1 mL, 0.175 mol) was added. The mixture was stirred at room temperature for 2 hours, producing a large amount of white solid. The solvent was evaporated under reduced pressure, and the remaining solid was dissolved in hydrochloric acid (10% aqueous solution, 150 mL). The aqueous layer was extracted with dichloromethane, dried over sodium sulfate, and the organic layer was concentrated. Purification using a silica column (developing solvent: hexane / ethyl acetate) gave 14.9 g of a white solid, carboxylic acid 1, in a 72% yield. 1 H-NMR(CDCl3,ppm):0.89(t,3H),1.5-1.8(m,3H),1.9-2.2(m,4H),2.53(m,1H),5.66(m,2H).

[0136] [Synthesis of carboxylic acid 2 (1-propyl-3-cyclohexene-1-carboxylic acid)] The same method as for carboxylic acid 1 was used, except that 1-iodopropane was used instead of iodoethane. Carboxylic acid 2 was obtained as a colorless liquid in 96% yield. 1 H-NMR(CDCl3,ppm):0.90(t,3H),1.2-1.4(m,2H),1.4-1.7(m,3H),1.8-2.2(m,4H),2.5(m,1H),5.66(m,2H).

[0137] [Synthesis of Compound 1] A zirconium isopropoxide solution (70% propanol solution, 4.0 g, 8.5 mmol) was placed in a flask and diluted with hexane (10 mL). Subsequently, carboxylic acid 1 (5.3 g, 34.1 mmol) was added. A reflux apparatus was attached to the flask, and the mixture was heated to reflux in a 90°C oil bath for 1 hour. The reaction solution was concentrated using an evaporator, and dichloromethane (5 mL) and acetonitrile (150 mL) were added to generate a white precipitate. This was filtered, and the collected material was dried in a vacuum oven to obtain a white powder of compound 1 (2.6 g). The resulting solid was dissolved in CDCl ３ The compound was dissolved in HCl and analyzed by NMR, and it was confirmed that the compound had the structure shown in Chemical Formula 1. 　1 H-NMR(CDCl3,ppm):0.7-1.0(m,3H),1.4-1.7(m,3H),1.7-2.0(m,3H),2.0-2.3(m,1H),2.4-2.6(m,1H),5.4-5.7(m,2H).

[0138]

[0139] [Synthesis of Compound 2] A white powder (5.8 g) of zirconium compound 2 represented by chemical formula 2 was obtained in the same manner as in the synthesis of compound 1, except that carboxylic acid 2 was used instead of carboxylic acid 1. 1 H-NMR(CDCl3,ppm):0.8-1.0(m,3H),1.1-2.6(m,10H),5.4-5.7(m,2H).

[0140]

[0141] [Synthesis of Compound 3] In the same manner as in the synthesis of Compound 1, a white powder (1.5 g) of zirconium compound 3 represented by chemical formula 3 was obtained using 1-methylcyclopropane-1-carboxylic acid (manufactured by TCI). 1 H-NMR (CDCl3, ppm): 1 H-NMR(CDCl3,ppm):0.7-1.0(m,3H),1.0-1.5(m,4H).

[0142]

[0143] As the resist material of Comparative Example 1, polystyrene (PS, weight average molecular weight 4000) manufactured by Aldrich was used.

[0144] <Preparation of Photosensitive Composition (Resist Solution)> The above compounds 1 to 3 were each dissolved in a solvent shown in Table 1 at a concentration of 5% by mass, and the solution was filtered through a 0.2 μm filter to obtain a resist solution. Also, the above polystyrene was dissolved in propylene glycol monomethyl ether acetate at a concentration of 2% by mass, and the solution was filtered through a 0.2 μm filter to obtain a resist solution.

[0145] <Formation of Resist Film> The prepared resist solution was applied onto a silicon wafer by spin coating, and then dried by heating on a hot plate at 90° C. for 90 seconds to form a resist film with a thickness of about 40 nm.

[0146] <Sensitivity measurement by EUV irradiation> The resist films obtained above were subjected to EUV blanket exposure, developed at 25°C using the developer and for the time shown in Table 1, and then spin-dried to obtain exposed films. The film thickness of the exposed films was measured with a contact step gauge. For all resists, a film thickness of 60 to 90% of the initial film thickness was confirmed, confirming that the evaluated resist films were sensitive to EUV.

[0147]

[0148] (Results) From the results in Table 1, it is clear that Compounds 1 to 3 of Examples 1 to 3 function as negative resist materials with a lower exposure dose than those of Comparative Examples. Therefore, it was confirmed that Compounds 1 to 3 are photosensitive compositions with excellent exposure sensitivity.

Claims

1. A transition metal cluster compound comprising a transition metal atom and a carboxylate ligand A, wherein the carboxylate ligand A has an alicyclic structure bonded to a carboxylate group, and the carbon in the alicyclic structure bonded to the carboxylate group is a quaternary carbon and may contain oxygen and / or a hydroxyl group.

2. The transition metal cluster compound according to claim 1, wherein the alicyclic structure is a 3- to 8-membered ring.

3. The transition metal cluster compound according to claim 1, which has a substituent R on the quaternary carbon to which the carboxylate group is bonded, and the substituent R is an organic group or a halogen atom.

4. The transition metal cluster compound according to claim 3, wherein the organic group is any one of a hydrocarbon group, an ester group, a sulfonyl group, an alkoxy group, an amide group, an amino group, and a carbonyl oxygen group.

5. The transition metal cluster compound according to claim 3, wherein the substituent R is an organic group having 1 to 10 carbon atoms.

6. The transition metal cluster compound according to claim 1, wherein the alicyclic structure bonded to the carboxylate group is a cycloalkyl group.

7. The transition metal cluster compound according to claim 1, wherein the carboxylate ligand A is represented by the following general formula B-1: In the above general formula B-1, the substituent R is an organic group or a halogen atom. Ａ are each independently a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms, and the substituent R Ａ may be the same or different, and n is an integer of 1 to 6.

8. The transition metal cluster compound according to claim 1, wherein the alicyclic structure is a cycloalkenyl group.

9. The transition metal cluster compound according to claim 1, wherein the carboxylate ligand A is at least one selected from those represented by the following general formulae C-1 to C-12: In the above general formulas C-1 to C-12, the substituent R is an organic group or a halogen atom. １ ~R １００ are each independently a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms. １ ~R １００ may be the same or different.

10. The transition metal cluster compound according to claim 1, wherein the transition metal atom is selected from the group consisting of zirconium, hafnium, and titanium.

11. The transition metal cluster compound according to claim 1, wherein a quaternary carbon bonded to the carboxylate group in the alicyclic structure has a substituent R, the substituent R being an organic group or a halogen atom, and another carbon in the alicyclic structure is bonded to either a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms.

12. The transition metal cluster compound of claim 1, wherein the transition metal cluster compound is electrically neutral.

13. A method for producing a transition metal cluster compound according to any one of claims 1 to 12, comprising the step of reacting a solution containing the transition metal atoms with a carboxylic acid having the structure of the carboxylate ligand A.

14. A photosensitive composition comprising the transition metal cluster compound according to any one of claims 1 to 12.

15. The photosensitive composition of claim 14, further comprising a solvent.

16. A photosensitive composition comprising the transition metal cluster compound according to any one of claims 1 to 12 in a concentration of 50 to 100% by mass of the total solids.

17. The photosensitive composition according to claim 14, which reacts with actinic radiation having a wavelength of 6 nm to 15 nm.

18. A pattern forming method comprising the steps of applying the photosensitive composition according to claim 14 to a substrate, exposing the applied photosensitive composition to actinic radiation, and developing the exposed photosensitive composition.

19. The pattern formation method according to claim 18, wherein the development is carried out using a developer, and the developer is an organic solvent having a solubility parameter (SP value) of 7.5 to 11.

20. A substrate having a patterned layer obtained by the patterning method according to claim 18.

21. A method for manufacturing a substrate, in which a pattern layer is formed by the pattern forming method according to claim 18.

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