Composition, container filled with composition, method for storing composition, and compound

Abstract

Provided is a composition which uses an aqueous solvent and is excellent in both solubility and storage stability of a metal complex. The composition contains an aqueous solvent and a first compound represented by formula (1).

Description

Composition, container filled with composition, method for storing composition, and compound

[0001] The present invention relates to a composition, a container filled with the composition, a method for storing the composition, and a compound.

[0002] Thin films containing metals such as iridium, gallium, and indium or metal compounds are used as thin-film electrode materials for various semiconductor devices such as DRAMs and FERAMs.Metal-containing thin films are manufactured by chemical vapor deposition methods such as CVD (chemical vapor deposition) and ALD (atomic layer deposition).

[0003] Many metal complexes have been known as source compounds used in chemical vapor deposition. For example, iridium complexes containing cyclopentadiene or its derivative, a cyclopentadienyl ligand, as a ligand are known. For example, Patent Document 1 listed below describes a method for producing an iridium-containing thin film using (1-methylcyclopentadienyl)(1,5-cyclooctadiene)iridium, in which 1-methylcyclopentadienyl and 1,5-cyclooctadiene are coordinated, as a chemical vapor deposition source. Patent Document 2 listed below describes a method for producing an iridium-containing thin film using (1-ethylcyclopentadienyl)(1,3-cyclohexadiene)iridium, in which 1-ethylcyclopentadienyl and 1,3-cyclohexadiene are coordinated, as a chemical vapor deposition source.

[0004] JP 2001-181841 A JP 2005-232142 A

[0005] In chemical vapor deposition, a metal-containing thin film is produced by vaporizing a source material containing a metal complex, transporting the resulting source gas to the substrate surface, and decomposing the metal complex. Heating is generally used to decompose the metal complex on the substrate surface. Alternatively, a reactive gas such as oxygen may be mixed with the source gas, and the metal complex may be decomposed by the action of the reactive gas in addition to heating. Furthermore, excitation energy such as plasma may also be used.

[0006] The metal complexes constituting the above-mentioned conventional chemical vapor deposition raw materials have high thermal stability and can be transported to a substrate in a stable state even after vaporization. However, conventional metal complexes have several problems due to their high thermal stability.

[0007] Conventional metal complexes have ligands with bulky substituents to provide thermal stability, which results in poor solubility in aqueous solvents, and in many cases requires the use of organic solvents. Furthermore, thin-film formation requires high-temperature processing, which can lead to problems such as the ignition of organic solvents, limiting the conditions for use. On the other hand, reducing the amount of organic solvent used leads to poor solubility, which can lead to the problem of precipitation of the metal complex during storage. Precipitation of the metal complex can cause unevenness on the surface of the metal-containing thin film, resulting in a decrease in the performance of the metal-containing thin film.

[0008] As described above, metal complexes have had problems of flammability during use and storage stability during storage. The present inventors, however, have conducted extensive research, believing that (1) flammability can be reduced by dissolving a metal complex in an aqueous solvent, and (2) the storage stability problem resulting from reduced solubility that may arise from the use of an aqueous solvent can be solved by examining the ligands of the metal complex.

[0009] An object of the present invention is to provide a composition which uses an aqueous solvent and which has excellent solubility and storage stability for a metal complex, a container filled with the composition, a method for storing the composition, and a compound which has excellent solubility in an aqueous solvent and excellent storage stability.

[0010] The invention made to solve the above problem is a composition containing a first compound represented by the following formula (1) and an aqueous solvent. (In formula (1), R １ and R ２ R each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms. ３ represents a group represented by the following formula (1A) or (1B): １ represents a chromium atom, a gallium atom, an iridium atom, an indium atom, a rhodium atom, a titanium atom, or a germanium atom; and n represents an integer of 0 to 4. (In formula (1A) and formula (1B), R １ , R ２ and X １ is R in formula (1). １ , R ２ and X １ * indicates the bonding position.)

[0011] Another invention made to solve the above problem is a composition-filled container comprising the above-mentioned composition and a container filled with the composition, wherein the ratio of the volume of void space excluding the volume occupied by the composition to the internal volume of the container is 5% by volume or more and 20% by volume or less, and the oxygen concentration in the void space is 0% by volume or more and 5% by volume or less.

[0012] Another invention made to solve the above-mentioned problem is a method for storing the above-mentioned composition, comprising the steps of filling a container with the composition so that the ratio of the volume of void space, excluding the volume occupied by the composition, to the internal volume of the container is 5% by volume or more and 20% by volume or less, and adjusting the oxygen concentration in the void space to 0% by volume or more and 5% by volume or less, and storing the container filled with the composition at a temperature of 5°C or more and 40°C or less.

[0013] Yet another invention made to solve the above problems is a compound represented by the following formula (2):

[0014] The composition of the present invention uses an aqueous solvent, and is excellent in both solubility and storage stability of the metal complex. By using a container filled with the composition of the present invention and a storage method of the present invention, precipitation of the metal complex can be prevented even when the composition is stored for a long period of time. The compound of the present invention is excellent in both solubility in aqueous solvents and storage stability.

[0015] Fig. 1 shows the results of FT-IR measurement of chromium complex 1 used in Example 1. Fig. 2 shows the results of FT-IR measurement of chromium complex 2 used in Comparative Example 1. Fig. 3 shows the results of TG-DTA measurement of chromium complex 1 used in Example 1. Fig. 4 shows the results of TG-DTA measurement of chromium complex 2 used in Comparative Example 1.

[0016] The composition according to one embodiment of the present invention, a container filled with the composition, a method for storing the composition, and a compound will be described in detail below.

[0017] Unless otherwise specified, the description of the upper and lower limits of a numerical range in this specification may be "less than or equal to" or "less than," and the lower limit may be "greater than or equal to" or "greater than." Furthermore, the upper and lower limits may be any combination of the disclosed numerical values. Furthermore, when a numerical range is indicated using the symbol "to," it means that the numerical range includes the upper and lower limit numerical values. For example, "1 to 6 carbon atoms" means "1 to 6 carbon atoms inclusive."

[0018] <Composition> A composition according to one embodiment of the present invention contains a first compound represented by formula (1) described below (hereinafter also referred to as “[A] metal complex”) and an aqueous solvent (hereinafter also referred to as “[B] aqueous solvent”).

[0019] The composition contains an aqueous solvent, and the metal complex (A) has high solubility in the aqueous solvent, and the metal complex (A) does not precipitate even when stored for a long period of time, exhibiting high storage stability. Furthermore, the composition exhibits excellent thermal stability.

[0020] The composition can be suitably used as a composition for forming a thin film by a chemical vapor deposition method such as a CVD method (chemical vapor deposition method) or an ALD method (atomic layer deposition method). The composition may be a film-forming composition, a vapor-deposited film-forming composition, a metal oxide film-forming composition, or a metal oxide vapor-deposited film-forming composition.

[0021] [Metal Complex (A)] The metal complex (A) is a compound represented by the following formula (1): The composition can contain one or more types of metal complex (A).

[0022] (In formula (1), R １ and R ２ R each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms. ３ represents a group represented by the following formula (1A) or (1B): １represents a chromium atom, a gallium atom, an iridium atom, an indium atom, a rhodium atom, a titanium atom, or a germanium atom; and n represents an integer of 0 to 4. (In formula (1A) and formula (1B), R １ , R ２ and X １ is R in formula (1). １ , R ２ and X １ * indicates the bonding position.)

[0023] In formula (1), formula (1A) and formula (1B), X １ Among the lines connecting the atoms, solid lines indicate covalent bonds and dashed lines indicate coordinate bonds.

[0024] In formula (1), a plurality of R １ and multiple R ２ In formula (1), X may be the same or different. １ If there are multiple Xs, １ may be the same or different.

[0025] "Number of carbon atoms" refers to the number of carbon atoms constituting the group. "Hydrocarbon group" includes "aliphatic hydrocarbon group" and "aromatic hydrocarbon group". "Aliphatic hydrocarbon group" includes "chain hydrocarbon group" and "alicyclic hydrocarbon group". From another perspective, "aliphatic hydrocarbon group" includes "saturated hydrocarbon group" and "unsaturated hydrocarbon group". "Chain hydrocarbon group" refers to a hydrocarbon group that does not contain a ring structure and is composed only of a chain structure, and includes both straight-chain hydrocarbon groups and branched-chain hydrocarbon groups. "Alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic ring as a ring structure and does not contain an aromatic ring, and includes both monocyclic alicyclic hydrocarbon groups and polycyclic alicyclic hydrocarbon groups. However, it does not have to be composed only of an alicyclic structure and may contain a chain structure as part of it. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring as a ring structure. However, it does not have to be composed only of an aromatic ring and may contain a chain structure or an alicyclic ring as part of it.

[0026] R １ and R ２Examples of the hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) include a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, and an aromatic hydrocarbon group having 6 to 10 carbon atoms.

[0027] Examples of chain hydrocarbon groups having 1 to 10 carbon atoms include methyl, ethyl, and n-propyl groups. Examples of alkyl groups include isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, and n-hexyl groups. Examples of alicyclic hydrocarbon groups having 3 to 10 carbon atoms include cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples of aromatic hydrocarbon groups having 6 to 10 carbon atoms include aryl groups such as phenyl and tolyl groups.

[0028] R １ and R ２ The hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) is preferably an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a tolyl group, and more preferably an alkyl group having 1 to 6 carbon atoms. From the viewpoint of achieving both solubility and heat resistance, a methyl group or an ethyl group is even more preferred, and a methyl group is particularly preferred.

[0029] X １ From the viewpoint of further improving solubility, the chromium atom preferably contains a chromium atom (Cr), and more preferably is a chromium atom (Cr).

[0030] n may be 4. The metal complex (A) also preferably contains a compound of formula (1) in which n is 4.

[0031] The metal complex (A) preferably contains a compound represented by the following formula (2), and more preferably is a compound represented by the following formula (2).

[0032]

[0033] In formula (2), among the lines bonded to the chromium atom (Cr), the solid lines represent covalent bonds and the dashed lines represent coordinate bonds.

[0034] The metal complex [A] can be synthesized by reacting a metal halide compound such as chromium trichloride with acetylacetonate in the presence of a water-soluble base compound such as ammonia, trimethylammonium hydroxide (TMAH), or urea, and a water-soluble acid compound such as hydrochloric acid.

[0035] The content of the metal complex (A) in the composition is preferably 1% by mass or more and 60% by mass or less, and more preferably 3% by mass or more and 40% by mass or less.

[0036] The metal complex [A] may form a salt with chloride ions, cyanate ions, etc. In addition, the metal complex [A] may exist as a hydrate containing water molecules. Specifically, the composition may further contain a second compound represented by the following formula (3). Z in the following formula (3) ― The counter anion represented by the formula (I) is determined by the reagent used in the neutralization treatment when synthesizing the metal complex [A]. For example, when hydrochloric acid is used, the counter ion is a chloride ion (Cl － ), and when cyanic acid is used, the counter ion is a cyanate ion (NCO － ) may occur.

[0037]

[0038] (In formula (3), R ４ and R ５ X each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms. ２ represents a chromium atom, a gallium atom, an iridium atom, an indium atom, a rhodium atom, a titanium atom, or a germanium atom. － indicates chloride or cyanate ions.)

[0039] In formula (3), a plurality of R ４ and multiple R ５ may be the same or different. ４ and R ５ Specific and preferred embodiments of the formula (1) are １ and R ２The specific and preferred embodiments are the same as those of X. ２ Preferably, R contains a chromium atom (Cr), and more preferably is a chromium atom (Cr). ４ and R ５ is R １ and R ２ It is the same kind as X. ２ is X １ It is of the same kind.

[0040] The second compound represented by the above formula (3) is preferably a compound represented by the following formula (3-1).

[0041] The total content of the [A] metal complex and components derived from the [A] metal complex (such as a salt of the [A] metal complex and a hydrate of the [A] metal complex) in the solid content of the composition is preferably 60 mass% or more, more preferably 70 mass% or more, even more preferably 80 mass% or more, and may be 90 mass% or more, 95 mass% or more, or 98 mass% or more.

[0042] The content of the solids (the metal complex [A], components derived from the metal complex [A], and other compounds) in the composition is preferably 1% by mass or more and 60% by mass or less, and more preferably 3% by mass or more and 40% by mass or less.

[0043] [B] Aqueous Solvent [B] refers to (1) water or (2) a mixed solvent containing water and an organic solvent, with water as the main component. "Containing water as the main component" means that the water content in the aqueous solvent [B] is 50% by mass or more.

[0044] The organic solvent is not particularly limited as long as it is miscible with water, and examples thereof include lower alcohols such as methanol, ethanol, and isopropanol.

[0045] The aqueous solvent (B) preferably does not substantially contain an organic solvent, and more preferably does not contain an organic solvent at all. The phrase "substantially does not contain an organic solvent" means that the composition may contain an organic solvent to the extent that it does not cause flammability problems.

[0046] The content of the organic solvent in the aqueous solvent [B] is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, still more preferably 0.1% by mass or less, and particularly preferably 0% by mass, relative to the total amount of the aqueous solvent [B].

[0047] In other words, the content of water in the aqueous solvent [B] is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 99% by mass or more, still more preferably 99.9% by mass, and particularly preferably 100% by mass, based on the total amount of the aqueous solvent [B].

[0048] The composition may further contain other components. However, the total content of the [A] metal complex, the component derived from the [A] metal complex (such as a salt of the [A] metal complex or a hydrate of the [A] metal complex), and the [B] aqueous solvent in the composition may be, for example, 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more. When the composition is substantially composed of only the [A] metal complex, the component derived from the [A] metal complex, and the [B] aqueous solvent, the storage stability of the composition can be further improved.

[0049] [Physical Properties of the Composition] The pH of the composition is preferably 4.0 or more and 7.5 or less. A pH of 4.0 or more can suppress a decrease in solubility of the metal complex [A] in the composition due to a ligand exchange reaction. A pH of 7.5 or less can facilitate the formation of a thin film using the composition. The lower limit of the pH of the composition may be 4.5, 5.0, 5.5, or 6.0. The upper limit of the pH of the composition may be 7.0 or 6.5.

[0050] <Container filled with composition> A container filled with a composition according to one embodiment of the present invention comprises the above-described composition and a container filled with the composition, wherein the ratio of the volume of void space excluding the volume occupied by the composition to the internal volume of the container is 5% by volume or more and 20% by volume or less, and the oxygen concentration in the void space is 0% by volume or more and 5% by volume or less.

[0051] The container is not particularly limited, and conventionally known containers such as glass, resin, etc. The gas filling the void can be, for example, an inert gas such as nitrogen gas.

[0052] <Method for storing composition> A method for storing a composition according to one embodiment of the present invention is a method for storing the composition described above, and includes a step of filling a container with the composition so that the ratio of the volume of void space, excluding the volume occupied by the composition, to the internal volume of the container is 5% by volume or more and 20% by volume or less, and adjusting the oxygen concentration in the void space to 0% by volume or more and 5% by volume or less (hereinafter also referred to as a "filling step"), and a step of storing the container filled with the composition at a temperature of 5°C or more and 40°C or less (hereinafter also referred to as a "storage step").

[0053] In the filling step, the composition is filled into the container so that the ratio of the volume of voids excluding the volume occupied by the composition to the internal volume of the container is 5% by volume or more and 20% by volume or less.

[0054] During filling, the oxygen concentration in the voids is adjusted to 0% by volume or more and 5% by volume or less. For example, a method for adjusting the oxygen concentration may be used, such as substituting the gas present in the voids with an inert gas such as nitrogen gas. By adjusting the oxygen concentration in this step, the composition can be stored for a long period of time while suppressing the generation of precipitates.

[0055] In the storage step, the container filled with the composition is stored at a temperature of 5°C or higher and 40°C or lower.

[0056] <Compound> A compound according to one embodiment of the present invention is a compound represented by the above formula (2). This compound is explained in the above section "[A] Metal Complex."

[0057] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0058] Synthesis of Chromium Complex Synthesis Example 1 A compound represented by the following formula (2) (hereinafter referred to as "chromium complex 1") was synthesized according to the following method.

[0059]

[0060] 0.2 mol of chromium trichloride was dissolved in ultrapure water. This solution was heated to 60°C, and 1.5 mol of acetylacetonate was added dropwise. The resulting mixed solution was neutralized by adding an alkaline aqueous solution and an acidic aqueous solution to a pH of approximately 7. The mixture was stirred overnight at temperatures ranging from 80°C to 110°C. The reaction solution was then filtered, and an organic solvent was added to the filtrate to extract the reaction product. The solvent in the extracted organic layer was distilled off. The residue was purified by adding an organic solvent to obtain chromium complex 1. The yield was 10% by mass. The product was identified and its structure confirmed using an LC-Mass spectrometer (Thermo Fisher Scientific's "UltiMate3000") and FT-IR (Bruker's "VERTEX70v"). Figure 1 shows the FT-IR spectrum of the resulting compound. The following peaks were observed, at 1570-1580 cm, due to the acetylacetonate ligand. －１ (C-O stretching vibration), 1520-1530cm －１ (CCC stretching vibration), 1420-1430cm －１ (CH ３ Stretching vibration), 1380-1400cm －１ (O-C-C-C-O stretching vibration), 1280-1290cm －１ (C-C-C stretching vibration).

[0061] As a result of the above identification, it was further confirmed that compounds represented by the following formulas (2-1), (2-2) and (2-3) were contained as by-products.

[0062]

[0063] <Preparation of Composition> [Example 1] Chromium complex 1 obtained in Synthesis Example 1 was dissolved in water at room temperature and with ultrasonic waves for 2 hours to obtain an aqueous solution containing chromium complex 1 (hereinafter referred to as "Cr aqueous solution 1"). Chromium complex 1 was well dissolved in water when Cr aqueous solution 1 was prepared. The pH of the obtained Cr aqueous solution 1 was measured using a pH measuring device. The pH of Cr aqueous solution 1 was 6.3.

[0064] Comparative Example 1 An aqueous solution containing chromium complex 2 (hereinafter referred to as "Cr aqueous solution 2") was prepared in the same manner as in Example 1, except that a compound represented by the following formula (4) (hereinafter referred to as "chromium complex 2") was used instead of chromium complex 1 obtained in Synthesis Example 1. However, chromium complex 2 did not dissolve in water. This is thought to be due to the difference in structure between chromium complex 1 and chromium complex 2. Figure 2 shows the FT-IR spectrum of the obtained chromium complex 2. The following peaks attributable to the acetylacetonate ligand were confirmed: 1570-1580 cm －１ (C-O stretching vibration), 1520-1530cm －１ (CCC stretching vibration), 1420-1430cm －１ (CH ３ Stretching vibration), 1380-1400cm －１ (O-C-C-C-O stretching vibration), 1280-1290cm －１ (C-C-C stretching vibration).

[0065]

[0066] [Evaluation of Complex Decomposition Characteristics] Thermogravimetric-differential thermal analysis (TG-DTA) was performed in an air atmosphere on chromium complex 1 and chromium complex 2 to evaluate the decomposition characteristics of the complexes. This evaluation test was performed using a NETZSCH "STA2500Regulus" analyzer. A chromium complex sample (sample mass: 10 mg) was filled into an alumina cell, and the mass change was observed at a heating rate of 20°C / min over a measurement temperature range of room temperature to 1000°C. The measurement results for chromium complex 1 are shown in Figure 3, and the measurement results for chromium complex 2 are shown in Figure 4.

[0067] Measurements in an air atmosphere confirmed that chromium complex 1 (Figure 3) exhibited an exothermic peak at higher temperatures than chromium complex 2 (Figure 4), indicating that it had higher heat resistance. These results suggest that the film formed from Cr aqueous solution 1 exhibits higher heat resistance than the film formed from Cr aqueous solution 2. Furthermore, it was confirmed that chromium complex 1 experienced mass loss at the same temperature as chromium complex 2, indicating that it has good vaporization characteristics and decomposition temperature. Because chromium complex 1 has good vaporization characteristics and decomposition temperature, it is believed that it can be used to form a film at a relatively low temperature using CVD or other methods.

[0068] [Evaluation of storage stability] For storage test sample 1, Cr aqueous solution 1 was filled into the void space of a container to a volume ratio of 70%, the void space was replaced with nitrogen, the container was sealed, and the container was stored for 30 days at 23° C. For storage test sample 2, Cr aqueous solution 1 was filled into the void space of a container to a volume ratio of 70%, the container was sealed, and the container was stored for 30 days at 23° C. After 30 days, storage test sample 1 and storage test sample 2 were visually observed for liquid color and the presence or absence of precipitates.

[0069] The liquid color was light yellow in both storage test sample 1 and storage test sample 2. Regarding the presence or absence of precipitates, no precipitates were confirmed in storage test sample 1, whereas black foreign matter was observed in storage test sample 2. This suggests that oxygen affects the generation of foreign matter, and it was found that storage stability can be improved by controlling the oxygen concentration in the container.

Claims

1. A composition containing a first compound represented by the following formula (1) and an aqueous solvent: (In formula (1), R １ and R ２ R each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms. ３ represents a group represented by the following formula (1A) or (1B): １ represents a chromium atom, a gallium atom, an iridium atom, an indium atom, a rhodium atom, a titanium atom, or a germanium atom; and n represents an integer of 0 to 4. (In formula (1A) and formula (1B), R １ , R ２ and X １ is R in formula (1). １ , R ２ and X １ * indicates the bonding position.) 2. X １ The composition of claim 1 , wherein is a chromium atom.

3. The composition according to claim 1, wherein the first compound comprises a compound represented by the following formula (2):

4. The composition according to claim 1, further comprising a second compound represented by the following formula (3): (In formula (3), R ４ and R ５ X each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms. ２ represents a chromium atom, a gallium atom, an iridium atom, an indium atom, a rhodium atom, a titanium atom, or a germanium atom. － indicates chloride or cyanate ions.) 5. The composition of claim 1, wherein said aqueous solvent is substantially free of organic solvents.

6. The composition according to claim 1, wherein the pH is 4.0 or more and 7.5 or less.

7. A composition-filled container comprising the composition according to any one of claims 1 to 6 and a container filled with the composition, wherein the ratio of the volume of void space excluding the volume occupied by the composition to the internal volume of the container is 5% by volume or more and 20% by volume or less, and the oxygen concentration in the void space is 0% by volume or more and 5% by volume or less.

8. A method for storing a composition according to any one of claims 1 to 6, comprising the steps of filling a container with the composition so that the ratio of the volume of void space, excluding the volume occupied by the composition, to the internal volume of the container is 5% by volume or more and 20% by volume or less, and adjusting the oxygen concentration in the void space to 0% by volume or more and 5% by volume or less; and storing the container filled with the composition at a temperature of 5°C or more and 40°C or less.

9. A compound represented by the following formula (2):

Images