Film formation methods, film formation materials, and new compound regulations

Abstract

The present invention provides a novel compound that has excellent storage stability (thermal stability), is liquid or has a low melting point at 25°C (1 atmosphere), has a high vapor pressure (volatility), and is suitable for uniform transportation. [Solution] L 1 ML 2 4 (M is at least one selected from the group consisting of Nb and Ta. 1 is a β-diketonate group. 2 is a halogen.)

Description

[Technical Field]

[0001] The present invention relates to Group V transition metals with specific ligands for use in, for example, the semiconductor and optical fields. [Background technology]

[0002] Oxide films of group V transition metals (Nb, Ta, etc.) have a high refractive index and high optical transparency. Therefore, these oxide films are used in the semiconductor and optical fields. For example, Nb2O5 has a high dielectric constant. Therefore, it is used as a ferroelectric material. It is also used as a highly integrated nonvolatile memory material. Nitrides of group V transition metals (e.g., NbN) have high work functions and are therefore used as liner or barrier materials in semiconductor applications that use conductive metals such as copper. Group V transition metals (Nb, Ta, etc.) are of course attracting attention in fields other than those mentioned above.

[0003] The Group V transition metal-containing film has been formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0004] CVD has the following problems: All raw materials required for film formation must be supplied to the film formation chamber at the same time. This makes it difficult to form a film with the desired composition ratio and physical properties. Furthermore, high temperatures are required for film formation, which can easily cause deterioration of semiconductor elements.

[0005] ALD has features not found in CVD. ALD is a self-limiting reaction. It has excellent step coverage. It is performed at a relatively low temperature. It can avoid degradation of device characteristics due to thermal diffusion.

[0006] However, when attempting to form a Group V transition metal (Nb, Ta, etc.) film by ALD, there have been few suitable source materials (precursor compounds: precursors).

[0007] One known precursor is Nb(OEt)5 (alkoxide compound). This compound has a low melting point and high vapor pressure. However, it has low thermal stability. This leads to side reactions, such as the formation of oligomers and polymers. This results in a high carbon content in the film during the deposition process of the Nb-containing film. Therefore, this compound is not desirable.

[0008] A known precursor is (tBuN)Nb(NEe2)3 (an imide-amide compound). This compound is liquid, making it easy to transport to the deposition chamber. However, when this compound is used for ALD deposition, the film contains a high amount of carbon. Furthermore, the inclusion of nitrogen is unavoidable. Therefore, this compound is not considered desirable.

[0009] A known precursor is Nb(NMe2)5 (amide compound). This compound is solid, has low volatility, and is poorly transportable to the deposition chamber. Furthermore, it has poor thermal stability. For example, it decomposes at 150°C. Furthermore, its hydrolysis resistance is poor. Furthermore, the inclusion of C and N in the film is unavoidable. Therefore, this compound is not desirable.

[0010] As a precursor, for example, NbCl5 (a halogen compound) is known. This compound is solid, has low volatility, and has poor transport properties to the deposition chamber. Therefore, this compound cannot be said to be preferable.

[0011] As a precursor, for example, NbCl4 (β-diketone) is known. This compound is a solid, has low volatility, and has poor transport properties to the deposition chamber. Therefore, this compound cannot be said to be preferable. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Patent No. 4859098 [Patent Document 2] Patent No. 5746034 [Non-patent literature]

[0013] [Non-Patent Document 1] SYNTHESIS,CRYSTALLOGRAPHY,AND REACTIVITY OF GROUP 4 AND 5 COORDINATION COMPLEXES SUPPORTED BY BULKY β-DIKETONATE LIGANDS by Sebastian M.Krajewski , Department of Chemistry , UniVersity of Colorado at Boulder 2020 Summary of the Invention [Problem to be solved by the invention]

[0014] The problem to be solved by the present invention is to provide a technology that can form a high-quality, conformal Group V transition metal-containing film using a liquid or low-melting-point compound that has excellent storage stability and thermal stability, has a high vapor pressure (volatility), and can be transported uniformly. [Means for solving the problem]

[0015] The present invention provides A novel compound, The novel compound is L 1 ML 2 4 (M is at least one selected from the group consisting of Nb and Ta. 1 is a β-diketonate group. 2 is a halogen. It is a liquid compound at 60℃ (1 atmosphere). Novel compounds are disclosed.

[0016] The present invention discloses the novel compound, which is preferably a liquid compound at about 55° C. (1 atmosphere).

[0017] The present invention discloses the novel compound, which is preferably a liquid compound at about 50° C. (1 atmosphere).

[0018] The present invention discloses the novel compound, which is preferably a liquid compound at about 43° C. (1 atmosphere).

[0019] The present invention discloses the novel compound, which is preferably a liquid compound at about 40° C. (1 atmosphere).

[0020] The present invention discloses the novel compound, which preferably has a single-stage TG weight loss curve.

[0021] The present invention relates to the novel compound, 1 However, preferably, F is a β-diketonate group.

[0022] The present invention discloses the novel compound, wherein the β-diketonate group is preferably an acetylacetonate group.

[0023] The present invention relates to the novel compound, 1 However, particularly preferred novel compounds are disclosed in which F is an acetylacetonate group.

[0024] The present invention relates to the novel compound, 1 However, the present invention discloses novel compounds in which the 1,1,1,5,5,5-hexafluoroacetylacetonate (hfac) group is particularly preferred.

[0025] The present invention relates to the novel compound, 2This invention discloses novel compounds in which

[0026] The present invention relates to the novel compound, 1 is hfac, and said L 2 This invention discloses novel compounds in which

[0027] The present invention discloses the novel compound, wherein M is Nb.

[0028] The present invention discloses the novel compound, wherein M is Ta.

[0029] The present invention provides A film-forming material, The material is L 1 ML 2 4 (M is Nb or Ta, L 1 is a β-diketonate group bearing F, and L 2 is a halogen.) A deposition material is disclosed.

[0030] The present invention discloses the film-forming material, wherein the compound is preferably a compound having a single-stage TG weight loss curve.

[0031] The present invention discloses the film-forming material, wherein the compound is preferably a compound that is liquid at about 60° C. (1 atmosphere).

[0032] The present invention discloses the film-forming material, wherein the compound is preferably a compound that is liquid at about 55° C. (1 atmosphere).

[0033] The present invention discloses the film-forming material, wherein the compound is preferably a compound that is liquid at about 50° C. (1 atmosphere).

[0034] The present invention discloses the film-forming material, wherein the compound is preferably a compound that is liquid at about 43° C. (1 atmosphere).

[0035] The present invention discloses the film-forming material, wherein the compound is preferably a compound that is liquid at about 40° C. (1 atmosphere).

[0036] The present invention discloses the film-forming material, wherein the β-diketonate group is preferably an acetylacetonate group.

[0037] The present invention provides the film-forming material, 1 However, the present invention discloses a film-forming material in which the acetylacetonate group having F is preferably an acetylacetonate group having F.

[0038] The present invention provides the film-forming material, 1 However, the present invention discloses a deposition material that is preferably hfac.

[0039] The present invention provides the film-forming material, 2 is Cl.

[0040] The present invention provides the film-forming material, 1 hfac,L 2 is Cl.

[0041] The present invention discloses the film-forming material, wherein M is Nb.

[0042] The present invention discloses the film-forming material, wherein M is Ta.

[0043] The present invention discloses a film-forming material comprising a compound represented by the above structural formula, which is suitable as a precursor for forming a Group V transition metal-containing film.

[0044] The film-forming material is a material suitable for film formation by CVD and / or ALD.

[0045] The film-forming materials are particularly suitable for film formation by ALD.

[0046] The present invention provides A film forming method, L 1 ML 2 4 (M is Nb or Ta, L 1 is a β-diketonate group bearing F, and L 2 is a halogen.) is supplied to a film-forming chamber to form a film on a substrate. A deposition method is disclosed.

[0047] The present invention discloses a film formation method in which, in order to form a Group V transition metal-containing film, a Group V transition metal precursor compound represented by the above structural formula is supplied into a film formation chamber, and a Group V transition metal-containing film is formed on a substrate placed in the film formation chamber.

[0048] The present invention discloses the film formation method, wherein the compound is preferably a compound having a single-stage TG weight loss curve.

[0049] The present invention discloses the film formation method, wherein the compound is preferably a compound that is liquid at about 60° C. (1 atmosphere).

[0050] The present invention discloses the film-forming method, wherein the compound is preferably a compound that is liquid at about 55° C. (1 atmosphere).

[0051] The present invention discloses the film formation method, wherein the compound is preferably a compound that is liquid at about 50° C. (1 atmosphere).

[0052] The present invention discloses the film-forming method, wherein the compound is preferably a compound that is liquid at about 43° C. (1 atmosphere).

[0053] The present invention discloses the film-forming method, wherein the compound is preferably a compound that is liquid at about 40° C. (1 atmosphere).

[0054] The present invention discloses the film-forming method, wherein the β-diketonate group is preferably an acetylacetonate group.

[0055] The present invention provides the film forming method, 1 However, the present invention discloses a film-forming method in which the F is preferably an acetylacetonate group.

[0056] The present invention provides the film forming method, 1 However, a film forming method is disclosed in which the film is preferably formed from hfac.

[0057] The present invention provides the film forming method, 2 is Cl.

[0058] The present invention provides the film forming method, 1 hfac,L 2 is Cl.

[0059] The present invention discloses the above-mentioned film formation method, wherein M is Nb.

[0060] The present invention provides the film forming method, wherein the M is Nb and the L 1 is hfac, and said L 2 is Cl.

[0061] The present invention discloses the above-mentioned film formation method, wherein M is Ta.

[0062] The present invention provides the film forming method, wherein the M is Ta and the L 1 is hfac, and said L 2 is Cl.

[0063] The present invention discloses the above-mentioned film formation method, which comprises a compound represented by the above-mentioned structural formula, which is suitable as a precursor for forming a Group V transition metal-containing film.

[0064] The film formation method is suitable for film formation by CVD and / or ALD.

[0065] The film formation method is particularly suitable for film formation by ALD.

[0066] Preferred Group V transition metal-containing films include, but are not limited to, Group V transition metal films, Group V transition metal oxide films, Group V transition metal nitride films, and Group V transition metal oxynitride films. [Effects of the Invention]

[0067] The Group V transition metal precursor proposed by the present invention is a liquid or low-melting-point compound. It has good transport properties for transporting to the deposition process of Group V transition metal-containing films. It is a compound with excellent thermal stability. It is less likely to decompose during transport to the deposition process of Group V transition metal-containing films. High-quality, conformal Group V transition metal-containing films can be formed. [Brief explanation of the drawings]

[0068] [Figure 1] TG (thermogravimetric analysis) diagram of (hfac)NbCl4 [Figure 2] TG diagram of (tfac)NbCl4 [Figure 3] TG diagram of (acac)NbCl4 [Figure 4] TG diagram of (thd)NbCl4 [Figure 5] TG comparison diagram of Example 1 [Figure 6] Schematic diagram of film formation equipment DETAILED DESCRIPTION OF THE INVENTION

[0069] The following detailed description provides preferred exemplary embodiments only and is not intended to limit the scope, applicability, or configuration of the present invention. Rather, it provides those skilled in the art with an enabling description for implementing preferred exemplary embodiments of the present invention. Various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the present invention, as defined by the appended claims.

[0070] The Group V transition metal compound of the present invention is sometimes described as a complex, but is also sometimes described as a precursor because it is suitable for use in CVD and / or ALD. Either notation can be considered to refer to the same thing.

[0071] The CVD is not limited to CVD in the narrow sense, but also includes CVD in the broad sense and similar CVD. Similarly, the ALD is not limited to ALD in the narrow sense, but also includes ALD in the broad sense and similar ALD. Examples include pulsed CVD, laser CVD, cyclic CVD (CCVD), metalorganic CVD (MOCVD), plasma-enhanced CVD (PECVD), high-density PECVD, photon-assisted CVD, plasma-photon-assisted CVD (PPECVD), thermal chemical vapor deposition, low-temperature chemical vapor deposition, chemically assisted vapor deposition, hot-filament chemical vapor deposition, CVD of liquid polymer precursors, deposition from supercritical fluids, low-energy CVD (LECVD), and plasma-enhanced ALD (PEALD). Other examples include CVD and ALD that employ radiation (X-rays, electron beams, electromagnetic waves, or light).

[0072] The Group V transition metal-containing film is considered to refer to metal films (films consisting only of Group V transition metals), alloy films (alloy films containing Group V transition metals), oxide films (oxide films or silicon oxide films containing Group V transition metals), nitride films (nitride films or silicon nitride films containing Group V transition metals), oxynitride films (oxynitride films containing Group V transition metals), carbide films (carbide films containing Group V transition metals), silicide films (silicide films containing Group V transition metals), and other films of various compositions. Any type of film containing Nb (and / or Ta) as one of its components is also included.

[0073] The first invention is a novel compound represented by the following general formula (I).

[0074] General formula (I) L 1 ML 2 4 (wherein M is Nb or Ta, and L 1 is a β-diketonate group, and L 2 is a halogen group.)

[0075] The novel compound is a compound that is liquid at 60°C (1 atmosphere). Preferably, it is a compound that is liquid at about 55°C (1 atmosphere). More preferably, it is a compound that is liquid at about 50°C (1 atmosphere). Even more preferably, it is a compound that is liquid at about 43°C (1 atmosphere). Particularly preferably, it is a compound that is liquid at a temperature (1 atmosphere) below about 40°C. Even if it is solid at room temperature (25°C) and atmospheric pressure (1 atmosphere), it is sufficient as long as it changes from solid to liquid by slight heating. Of course, it may also be liquid at room temperature (25°C) and atmospheric pressure (1 atmosphere). The novel compounds preferably exhibited a single-stage TG weight loss curve.

[0076] Said L 1 However, preferably, it is a β-diketonate group having F. 1 When the compound represented by the general formula (I) was a β-diketonate group not having F, the compound was a solid with a high melting point. The β-diketonate group is preferably an acetylacetonate group. Partially substituted acetylacetonate groups are also included. A 1,1,1,5,5,5-hexafluoroacetylacetonate (hfac) group is particularly preferred.

[0077] Examples of the compound include (hfac)NbCl4, (hfac)NbBr4, (hfac)NbI4, (hfac)TaCl4, (hfac)TaBr4, (hfac)TaI4, etc. However, the compound is not limited to these and may be (hfac)NbCl2Br2.

[0078] Said L 2 was more preferably Cl.

[0079] It is particularly preferable that the compound is in a liquid state at about 30 to 40°C (1 atmosphere) and has a high vapor pressure (volatility). 1 is hfac and L 2 was Cl. In the following examples, only Nb is disclosed as M, but those skilled in the art will understand that Nb can be replaced with Ta.

[0080] A typical halogen compound, NbCl5, is a solid at 25°C (1 atm) and has low vapor pressure (volatility). For this compound to be a liquid (at 30-40°C (1 atm)), it is important that the group bonded to the group V transition metal M has a structure containing one β-diketonate group (where this β-diketonate group contains F) and four halogens. Among these, hfac is the most preferred β-diketonate group.

[0081] When decomposition occurs during the deposition of a Group V transition metal-containing film, impurities, particularly carbon (C), are likely to be introduced into the film. To deposit a high-purity Group V transition metal-containing film, it is important not only to deposit the film at a higher temperature without decomposing the Group V transition metal precursor, but also to minimize the organic components contained in the Group V transition metal precursor, i.e., the number of substituents (or alkyl groups in the case of alkyl groups) and / or the number of carbon atoms contained in the substituents bonded to the Group V transition metal M. For this reason, it was important that the group bonded to the Group V transition metal M have a structure containing one β-diketonate group (provided that this β-diketonate group contains F) and four halogens. Among these, hfac was the preferred β-diketonate group.

[0082] Precursors used in depositing Group V transition metal-containing films are preferably those with a single-stage TG weight loss curve, because precursors with multiple stages in the TG weight loss curve are prone to decomposition.

[0083] The second invention is a film-forming material for a Group V transition metal film used to form a Group V transition metal-containing film. The material is at least a compound represented by the general formula (I) (the compound described above). The term "at least" means that the compound represented by the general formula (I) may be used alone or in combination with other materials (compounds). In other words, the material may be in the form of a composition.

[0084] The third invention is a method for forming a Group V transition metal-containing film using the above-mentioned film-forming material as a precursor. CVD or ALD techniques are preferably used for film formation in the present invention. ALD is particularly suitable.

[0085] Generally, in the field of metal-containing film deposition, substrate temperature is an important process variable. Typical substrate temperatures are about 150°C to about 550°C. Higher substrate temperatures can promote faster film growth rates. Therefore, it is desirable to find Group V transition metal precursors that can deposit Group V transition metal-containing films at higher temperatures without decomposition. The compounds represented by the general formula (I) above fulfill this need.

[0086] Generally, in the field of metal-containing film deposition, precursors that are liquid under the process conditions for the deposition of metal-containing films are preferred over precursors that are solid under the process conditions for the deposition of metal-containing films. Liquid precursors, compared to solid precursors, can transport the precursor more uniformly during the metal-containing film deposition process. In one embodiment, a carrier gas is bubbled through the metal-containing film precursor under suitable process conditions. Bubbling the gas through the liquid is an effective means of providing a longer gas-liquid contact time and a larger gas-liquid contact area. This aims to achieve a gas flow saturated with the vaporized liquid precursor. Achieving a saturated carrier gas maximizes the precursor transport rate and is advantageous for operating the metal-containing film deposition process. The compound represented by the general formula (I) satisfies the above demands. According to the present invention, the problem that the present invention aims to solve has been solved.

[0087] [Example] The present invention will be described in more detail below. The following description is merely a preferred exemplary embodiment, and the present invention is not limited thereto. Various modifications are also included without departing from the spirit and scope of the present invention as defined in the claims.

[0088] [Example 1] [Synthesis Example 1: (hfac)NbCl4] The synthesis was carried out under a nitrogen atmosphere. 54.0 g of NbCl5 and 2 L of hexane were added to a vessel. 41.6 g of hfac-H (1,1,1,5,5,5-hexafluoroacetylacetone) was slowly added to the vessel. The mixture was stirred in the vessel. After stirring at room temperature, the solvent of the resulting reaction mixture was removed by vacuum distillation. The resulting crude product was purified by vacuum distillation. An orange liquid was obtained. This orange liquid changed to an orange solid. This substance (compound) was solid at 25°C (1 atm). Its melting point was 30-40°C. It was a low-melting-point compound.

[0089] The compound was confirmed to be (hfac)NbCl4 using an NMR device (BRUKER AVANCEIII400).

[0090] The weight loss rate of the compound in thermogravimetric analysis (TG) was 99.5%, and the weight loss rate at 50% (T 50 The solubility of the compound was 154.9°C (see Figure 1). This compound has good volatility and good thermal stability. Therefore, it was a suitable precursor for forming Nb-containing films. The thermogravimetric analysis (TG) was performed using a TG-DTA 8122 / S manufactured by Rigaku Corporation.

[0091] [Synthesis Example 2: (tfac)NbCl4] Synthesis was carried out in the same manner as in Synthesis Example 1, except that hfac-H was replaced with tfac-H (trifluoroacetylacetone). The crude product was purified by vacuum distillation. An orange liquid was obtained. This orange liquid changed to an orange solid. This substance (compound) was solid at 25°C (1 atm). The melting point was 40-50°C.

[0092] The compound was confirmed to be (tfac)NbCl4 using AVANCEIII400.

[0093] The weight loss of the compound in thermogravimetric analysis (TG) was multi-stage (see Figure 2). The compound cannot be said to be a precursor that can be uniformly supplied in the transport process in the deposition process of the Nb-containing film. In other words, it cannot be said to be a suitable precursor for forming the Nb-containing film.

[0094] [Synthesis example 3: (acac)NbCl4] Synthesis was carried out in the same manner as in Synthesis Example 1, except that hfac-H was replaced with acac-H (acetylacetone). The crude product obtained was purified by vacuum sublimation. An orange solid was obtained. This substance (compound) was solid at 25°C (1 atm). Its melting point was 130-140°C. It was a high-melting-point compound.

[0095] The compound was confirmed to be (acac)NbCl4 using AVANCEIII400.

[0096] The weight loss of the compound in thermogravimetric analysis (TG) was multi-stage (see Figure 3). The compound cannot be said to be a precursor that can be uniformly supplied in the transport process in the deposition process of the Nb-containing film. In other words, it cannot be said to be a suitable precursor for forming the Nb-containing film.

[0097] [Synthesis example 4: (thd)NbCl4] Synthesis was carried out in the same manner as in Synthesis Example 1, except that hfac-H was replaced with thd-H (2,2,6,6-tetramethyl-3,5-heptadione). The crude product was purified by vacuum sublimation. An orange solid was obtained. This substance (compound) was solid at 25°C (1 atm). Its melting point was 130-140°C. It was a high-melting-point compound.

[0098] The compound was confirmed to be (thd)NbCl4 using AVANCEIII400.

[0099] The weight loss rate of the compound in thermogravimetric analysis (TG) was 85.2%, and the weight loss rate at 50% temperature (T 50 ) was 290.3°C (see Figure 4). In addition, since the melting point was 130 to 140°C, it was poor in volatility. Moreover, it was poor in thermal stability. Therefore, it is difficult to say that it is a suitable precursor for forming a Nb-containing film.

[0100] The state and T of the compound 50 is shown in Table 1. Table-1 State Melting point (℃) T 50 (℃) TG volatilization rate (%) Synthesis Example 1 Solid 30°C or higher but lower than 40°C 154.9 99.5 Synthesis Example 2 Solid 40℃ or higher and lower than 50℃ Multi-stage reduction - Synthesis example 3 Solid 130℃ or higher and 140℃ or lower Multi-stage reduction - Synthesis Example 4 Solid 130℃ or higher and 140℃ or lower 290.3 85.2

[0101] (hfac)NbCl4 was a solid (25°C (1 atm)) but had a low melting point (30-40°C (1 atm)). 50 The temperature was 154.9°C. The weight loss rate was 99.5%, and the TG weight loss curve was one step. (acac)NbCl4 is a solid like (hfac)NbCl4, but its melting point is high (130-140°C (1 atm)). The TG weight loss curve showed multiple stages. 50 This suggests that the compound is easily decomposed and lacks thermal stability, making it unsuitable for use in film formation using CVD, ALD, etc. Although (hfac)NbCl4 and (acac)NbCl4 have the same number of Cl atoms bonded to Nb, the only difference is the element contained in the β-diketonate group, i.e., F in (hfac) and H in (acac). No one could have predicted that this difference would cause such a large difference in melting point and in the TG weight loss curve (one step vs. multiple steps), i.e., such a large difference in volatility and thermal stability. This was discovered for the first time by the present inventors. This indicates that (hfac)NbCl4 is a better choice than (acac)NbCl4 as a precursor in the deposition process of metal-containing films.

[0102] (thd)NbCl4 is a solid like (hfac)NbCl4, but has a high melting point (130-140°C (1 atm)). 50 The temperature was 290.3°C. The TG weight loss rate was 85.2%. 50 Compounds with low TG weight loss (volatility) and high TG weight loss (volatility) are highly volatile and thermally stable. (hfac)NbCl4 and (thd)NbCl4 have the same number of Cl bonded to Nb, but the only difference is the element contained in the β-diketonate group, i.e., F in (hfac) and CH3 in (thd). This difference caused a large difference in melting point, T 50 No one could have predicted that the large differences in volatility and thermal stability would result from the addition of NbCl4. This finding was first discovered by the present inventors, and it demonstrates that (hfac)NbCl4 is a better choice than (thd)NbCl4 as a precursor in the deposition process of metal-containing films.

[0103] The compound of Synthesis Example 2: (tfac)NbCl4 was a solid (25°C (1 atm)) but had a low melting point (40-50°C (1 atm)). However, the TG weight loss curve showed multiple stages. 50 It was not possible to clearly determine whether the compound is easily decomposed or lacks thermal stability. Therefore, the compound of Synthesis Example 2 is not as preferable as the compound of Synthesis Example 1 as a precursor compound for film formation. Although (hfac)NbCl4 and (tfac)NbCl4 have the same number of Cl atoms bonded to Nb, the only difference is the β-diketonate group, i.e., (hfac) has six F atoms, while (tfac) has three. However, no one could have predicted that this difference would cause a clear difference in the TG curve behavior, i.e., a large difference in volatility and thermal stability. This was discovered for the first time by the present inventors. This indicates that (hfac)NbCl4 is a better choice than (tfac)NbCl4 as a precursor in the deposition process of metal-containing films.

[0104] NbCl5 (all five substituents are Cl) is a solid (25°C (1 atm)) with a high melting point (200-210°C). 50 The temperature was 175°C and the TG weight loss rate was 99.0%. Generally, as the molecular weight of the sample increases, T 50The difference between NbCl5 and (hfac)NbCl4 is that one Cl bonded to Nb is replaced by (hfac). This difference causes a large difference in melting point, T 50 No one could have predicted that the difference in volatility, i.e., the difference in the solubility of NbCl4 and NbCl5, would have been significant. This finding was first discovered by the present inventors, and it demonstrates that (hfac)NbCl4 is a better choice than NbCl5 as a precursor in the deposition process of metal-containing films.

[0105] [Example 2] Figure 6 is a schematic diagram of a film formation apparatus, in which 1 is a container for a Nb precursor, 2 is a heater, 3 is a container for a reactant (e.g., HO), 4 is a heater, 5 is a substrate, 6 is a film formation chamber, and 7 is a pump. Using the apparatus shown in Figure 6, an Nb-based film was formed on a substrate 5. That is, the novel compound (hfac)NbCl4 was used as a precursor to form an Nb-based film. For example, the precursor in the container 1 was introduced into the film formation chamber 6 using a pressurized gas (e.g., nitrogen gas), and the reactant (e.g., HO) in the container 3 was introduced into the film formation chamber 6 using a pressurized gas (e.g., nitrogen gas), thereby forming an Nb-based film on the heated substrate 5. The Nb-based film obtained by the above method was confirmed to be a high-purity film (oxide film) by X-ray photoelectron spectroscopy (XPS).

[0106] [Example 3] In Example 2, the film was formed by CVD, and in Example 3, the film was formed by ALD. The Nb-based film obtained in this example was also confirmed by XPS to be a high-purity film (oxide film).

[0107] It will be understood that many further variations in the details of materials, steps, components, etc., described and shown herein to illustrate the nature of the invention may be made by those skilled in the art within the principles and scope of the invention as expressed in the appended claims.

[0108] It is not intended that the present invention be limited to the foregoing examples and / or embodiments.

Claims

1. A film forming method, L １ ML ２ ４ (M is Nb or Ta, L １ is a β-diketonate group having F, and L ２ is a halogen.) is supplied to a film-forming chamber to form a film on a substrate. Film formation method.

2. Said L １ is an acetylacetonate group having F The film forming method according to claim 1.

3. Said L １ is hfac The film forming method according to claim 2.

4. Said L １ is hfac, and L ２ is Cl The film forming method according to claim 3.

5. The compound has a single-stage TG weight loss curve. The film forming method according to any one of claims 1 to 4.

6. The compound is a liquid at 60°C (1 atmosphere). The film forming method according to any one of claims 1 to 4.

7. Said L ２ is Cl The film forming method according to claim 1.

8. The M is Nb The film forming method according to claim 1.

9. The M is Ta The film forming method according to claim 1.

10. A film-forming material, The material is L １ ML ２ ４ (M is Nb or Ta, L １ is a β-diketonate group having F, and L ２ is a halogen. Film deposition materials.

11. The compound has a single-stage TG weight loss curve. The film-forming material of claim 10.

12. The compound is a liquid at 60°C (1 atmosphere). The film-forming material according to claim 10 or 11.

13. Said L １ is an acetylacetonate group having F The film-forming material of claim 10.

14. Said L １ is hfac The film-forming material of claim 10.

15. Said L ２ is Cl The film-forming material of claim 10.

16. Said L １ is hfac, L ２ is Cl The film-forming material of claim 10.

17. The M is Nb The film-forming material of claim 10.

18. The M is Ta The film-forming material according to claim 10

19. A novel compound, The novel compound is L １ ML ２ ４ (M is at least one selected from the group consisting of Nb and Ta. １ is a β-diketonate group. ２ is a halogen. It is a liquid compound at 60°C (1 atmosphere). New compound.

20. The compound has a single-stage TG weight loss curve.

20. The novel compound of claim 19.

21. Said L １ is a diketonate group having F 20. The novel compound of claim 19.

22. Said L １ is hfac 20. The novel compound of claim 19.

23. Said L １ is hfac, L ２ is Cl 20. The novel compound of claim 19.

24. Said L ２ is Cl 20. The novel compound of claim 19.

25. The M is Nb 20. The novel compound of claim 19.

26. The M is Ta 20. The novel compound of claim 19.

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