Hafnium compound-containing sol-gel solution and hafnia-containing film

Abstract

To provide a hafnium compound-containing sol-gel solution which enables the formation of a Hafnia-containing film especially superior in etching resistance, and a Hafnia-containing film formed by use of the hafnium compound-containing sol-gel solution.SOLUTION: A hafnium compound-containing sol-gel solution comprises: alcohol serving as a solvent; and a hafnium compound which makes a Hafnia source. The hafnium compound-containing sol-gel solution contains one or more elements M selected from Zr, Ti and Nb, in which the mass ratio WM / WHf of a content WM of the element M to a content WHf of Hf as metal components is within a range of 0.2% or more and 5.0% or less. A Hafnia-containing film contains: Hafnia (HfO2); and one or more elements M selected from Zr, Ti and Nb, in which the mass ratio WM / WHfO2 of a content WM of the element M to a content WHfO2 of the HfO2 is within a range of 0.05% or more and 5.0% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hafnium compound-containing sol-gel solution used in forming a hafnia-containing film containing hafnia (also known as hafnium (IV) oxide, chemical formula: HfO2) on the surface of a substrate, and to a hafnia-containing film formed using this hafnium compound-containing sol-gel solution. [Background technology]

[0002] Conventionally, the above-mentioned hafnia-containing film has been formed on the surface of various substrates as a hard coat film with high hardness or as an etching mask. By forming a patterned hafnia-containing film on the surface of a substrate as an etching mask and then etching the surface of the substrate, the portions on which the hafnia-containing film is formed remain unetched, forming a specific pattern on the surface of the substrate.

[0003] As a method for forming the above-mentioned hafnia-containing film, for example, as disclosed in Patent Documents 1 and 2, a method has been proposed in which a hafnium compound-containing sol-gel solution containing a hafnium compound that serves as a hafnia source is used. In Patent Documents 1 and 2, a hafnia-containing film is formed by applying a sol-gel liquid containing a hafnium compound to the surface of a substrate and curing the applied film of the sol-gel liquid containing the hafnium compound. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-267822 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-187738 Summary of the Invention [Problem to be solved by the invention]

[0005] Recently, patterns formed on the surface of a substrate have become denser, and therefore, there is a demand for etching treatment to be performed with high precision. There is also a demand for etching treatment of a substrate to be performed more efficiently. For this reason, hafnia-containing films used as etching masks are required to have higher etching resistance than ever before.

[0006] The present invention has been made in view of the above-mentioned circumstances, and aims to provide a hafnium compound-containing sol-gel liquid capable of forming a hafnia-containing film having particularly excellent etching resistance, and a hafnia-containing film formed using this hafnium compound-containing sol-gel liquid. [Means for solving the problem]

[0007] In order to solve the above problems, the present inventors have conducted extensive research and have come to the following findings. In a hafnia-containing film, increasing the crystallinity improves its etching resistance. Furthermore, since one or more elements M selected from Zr, Ti, and Nb have a lower crystallization temperature than Hf, adding an appropriate amount of element M to a hafnium compound-containing sol-gel solution causes element M to rapidly crystallize and become seed crystals, accelerating the crystallization of Hf and enabling the formation of a hafnia-containing film with high crystallinity and excellent etching resistance.

[0008] The present invention has been made based on the above findings, and the hafnium compound-containing sol-gel solution of the present invention is a hafnium compound-containing sol-gel solution containing an alcohol as a solvent and a hafnium compound as a hafnia source, and contains one or more elements M selected from Zr, Ti, and Nb, and the content W of Hf as a metal component is Hf and the content W of the element M M Mass ratio W M / W Hf is 0.2% or more 1.0% or less Within the range The element M includes Zr. It is characterized by the following.

[0009] The hafnium compound-containing sol-gel solution of this configuration contains one or more elements M selected from Zr, Ti, and Nb together with Hf, and the content W of Hf as a metal component Hf and the content W of the element M M Mass ratio W M / W Hf Since the content of Zr in the sol-gel solution is within the range of 0.2% to 5.0%, one or more elements M selected from Zr, Ti, and Nb crystallize to become seed crystals, which promotes the crystallization of Hf. Therefore, by drying and baking this hafnium compound-containing sol-gel solution, it is possible to form a hafnia-containing film with high crystallinity and excellent etching resistance.

[0010] In the hafnium compound-containing sol-gel solution of the present invention, the alcohol serving as the solvent is preferably a lower alcohol having 5 or less carbon atoms. In this case, since a lower alcohol having 5 or less carbon atoms is used as the solvent, the solvent can be evaporated relatively easily, and a hafnia-containing film can be stably formed.

[0011] In the hafnium compound-containing sol-gel solution of the present invention, the content of the hafnium compound is preferably in the range of 0.05 wt % to 10 wt %. In this case, since the content of the hafnium compound is set within the above range, a hafnia-containing film can be reliably formed by drying and baking the hafnium-compound-containing sol-gel liquid.

[0012] Furthermore, the hafnium compound-containing sol-gel liquid of the present invention preferably contains a polyalcohol having one or more ether groups in the molecule as a wettability improver. Polyalcohols have a high affinity for hydrophilic surfaces because they contain multiple hydroxyl groups (-OH groups) in their molecules, and also have a high affinity for hafnium compound-containing sol-gel liquids because they contain ether groups (-O-). Therefore, by adding polyalcohol to the hafnium compound-containing sol-gel liquid, it becomes possible to uniformly apply the hafnium compound-containing sol-gel liquid to the surface of a hydrophilic substrate.

[0013] In the hafnium compound-containing sol-gel solution of the present invention, the content of the polyalcohol is preferably in the range of 0.05 wt % to 20 wt %. In this case, since the content of the polyalcohol is set within the above range, it becomes possible to apply the hafnium compound-containing sol-gel liquid more uniformly to the surface of the hydrophilic substrate.

[0014] The hafnium compound-containing sol-gel solution of the present invention preferably further contains a stabilizer. In this case, since the sol-gel solution contains a stabilizer, deterioration of the hafnium compound-containing sol-gel solution can be suppressed, making it easy to handle.

[0015] The hafnia-containing film of the present invention contains hafnia (HfO2) and one or more elements M selected from Zr, Ti, and Nb, and the content W of the HfO2 is HfO2 and the content W of the element M M Mass ratio W M / W HfO2 is 0.05% or more 1.0% or less Within the range The element M includes Zr. It is characterized by the following.

[0016] According to the hafnia-containing film having this configuration, the content W of HfO2 HfO2 and the content W of one or more elements M selected from Zr, Ti, and Nb. M Mass ratio W M / W HfO2Since the content of Zr is within the range of 0.05% or more and 5.0% or less, crystallization is promoted by one or more elements M selected from Zr, Ti, and Nb, resulting in a high degree of crystallization and excellent etching resistance. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a hafnium compound-containing sol-gel liquid capable of forming a hafnia-containing film having particularly excellent etching resistance, and a hafnia-containing film formed using this hafnium compound-containing sol-gel liquid. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a flow diagram showing a method for producing a hafnium compound-containing sol-gel liquid according to one embodiment of the present invention. [Figure 2] FIG. 1 is a flow diagram showing a method for producing a hafnia-containing film according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The hafnium compound-containing sol-gel solution and hafnia-containing film according to the embodiments of the present invention will be described below.

[0020] The hafnium compound-containing sol-gel solution of this embodiment contains alcohol as a solvent and a hafnium compound as a hafnia source. The hafnium compound-containing sol-gel solution of this embodiment contains one or more elements M selected from Zr, Ti, and Nb, and the content W of Hf as a metal component is Hf and the content W of one or more elements M selected from Zr, Ti, and Nb M Mass ratio W M / W Hf is set to be within the range of 0.2% to 5.0%. In addition, the mass ratio W M / W Hfis preferably 0.25% or more, and more preferably 0.3% or more. M / W Hf is preferably set to 1.0% or less, and more preferably set to 0.5% or less.

[0021] Furthermore, the hafnium compound-containing sol-gel solution of this embodiment may contain, in addition to the solvent and hafnium compound, a polyalcohol having one or more ether groups in the molecule as a wettability improver. Furthermore, the hafnium compound-containing sol-gel solution of this embodiment may contain a stabilizer.

[0022] In the hafnium compound-containing sol-gel solution of this embodiment, the content of the hafnium compound serving as the hafnia source is preferably within the range of 0.05 wt % to 10 wt %. Furthermore, when polyalcohol is contained as a wettability improver, the content of polyalcohol is preferably within the range of 0.05 wt % to 20 wt %. When a stabilizer is contained, the content of the stabilizer is preferably 20 wt % or less.

[0023] That is, the composition of the hafnium compound-containing sol-gel liquid of this embodiment is preferably such that the hafnium compound content is in the range of 0.05 wt% to 10 wt%, the polyalcohol content is in the range of 0 wt% to 20 wt%, the stabilizer content is in the range of 0 wt% to 20 wt%, and the remainder is solvent.

[0024] Here, it is preferable to use a lower alcohol having 5 or less carbon atoms as the alcohol solvent. A lower alcohol is an alcohol having 5 or less carbon atoms in the molecule and 2 or less hydroxyl groups (-OH groups).

[0025] Examples of lower alcohols include monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutyl alcohol, tert-butyl alcohol, n-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, and neopentyl alcohol, as well as dihydric alcohols such as ethylene glycol, propylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol. In this embodiment, it is preferable to use a lower alcohol, such as propanol or butanol, as the solvent.

[0026] Examples of hafnium compounds that serve as hafnia sources include hafnium compounds selected from the group consisting of hafnium halides, hafnium halites, hafnium hypohalites, hafnium halites, hafnium perhalites, hafnium inorganic acid salts, hafnium organic acid salts, hafnium alkoxides, and hafnium complexes.

[0027] In this embodiment, it is preferable to use a hafnium alkoxide having 5 or less carbon atoms as the hafnium compound serving as the hafnia source. Specifically, it is preferable to use hafnium (IV) methoxide, hafnium (IV) ethoxide, hafnium (IV) propoxide, hafnium butoxide, hafnium (IV) n-butoxide, hafnium (IV) t-butoxide, hafnium (IV) pentoxide, hafnium (IV) isopropoxide monoisopropylate, etc.

[0028] The element M (one or more elements selected from Zr, Ti, and Nb) is contained as a compound of element M selected from the group consisting of halides, halites, hypohalites, halogen acid salts, perhalites, inorganic acid salts, organic acid salts, alkoxides, and complexes of element M. As the compound of element M, it is preferable to use an alkoxide having 5 or less carbon atoms. By drying and firing the hafnium compound-containing sol-gel solution containing the hafnium compound that serves as the hafnia source, hafnia (HfO2) is formed, and a hafnia-containing film is formed.

[0029] As the polyalcohol having one or more ether groups in the molecule, which serves as a wettability improver, it is preferable to use, for example, diethylene glycol, triethylene glycol, tetraethylene glycol, diglycerol, dipentaerythritol, or the like. Polyalcohols with one or more ether groups in their molecules have high affinity for hydrophilic surfaces due to the presence of multiple hydroxyl groups (-OH groups) in their molecules, and also have high affinity for hafnium compound-containing sol-gel solutions due to the presence of ether groups (-O-) in their molecules. Therefore, the hafnium compound-containing sol-gel solution containing this polyalcohol can be uniformly applied to the surface of a hydrophilic substrate.

[0030] Here, by setting the content of polyalcohol having one or more ether groups in the molecule in the hafnium compound-containing sol-gel liquid to the range of 0.05 wt% to 20 wt%, wettability can be sufficiently improved, and the hafnium compound-containing sol-gel liquid can be uniformly applied to the hydrophilic substrate surface. The lower limit of the content of the polyalcohol having one or more ether groups in the molecule is more preferably 0.1 wt% or more, and even more preferably 0.2 wt% or more, while the upper limit of the content of the polyalcohol having one or more ether groups in the molecule is more preferably 10 wt% or less, and even more preferably 5 wt% or less.

[0031] As the stabilizer, for example, acetylacetone, ethyl acetoacetate, acetoin, hydroxyacetone, malonic acid, acetic acid, acetic anhydride, lactic acid, oxalic acid, citric acid, tartaric acid, triethanolamine, diethanolamine, etc. are preferably used. By adding a stabilizer to the hafnium compound-containing sol-gel liquid, deterioration of the hafnium compound-containing sol-gel liquid can be suppressed and the handleability of the hafnium compound-containing sol-gel liquid can be improved. Therefore, a stabilizer may be added as needed.

[0032] Here, the content of the stabilizer in the hafnium compound-containing sol-gel liquid is preferably within the range of 0 wt % to 10 wt %. The lower limit of the stabilizer content is preferably 0.05 wt% or more, and more preferably 0.1 wt% or more, while the upper limit is preferably 8 wt% or less, and more preferably 5 wt% or less.

[0033] Next, the method for producing the hafnium compound-containing sol-gel solution according to the present embodiment will be described with reference to the flow chart of FIG.

[0034] The method for producing a hafnium compound-containing sol-gel solution according to this embodiment includes a hafnium compound addition step S01 for adding a hafnium compound to an alcohol solvent, and a reflux step S02 for refluxing the solvent containing the hafnium compound, which serves as a hafnia source, as shown in Fig. 1. A solvent addition step S03 may also be included to adjust the composition. Furthermore, when a polyalcohol serving as a wetting improver is added, a polyalcohol adding step S04 is included, and when a stabilizer is added, a stabilizer adding step S05 is included.

[0035] In the hafnium compound addition step S01, the hafnium compound is added to the alcohol solvent while the alcohol solvent is heated and stirred. Here, as a metal component, the content of Hf W Hfand the content W of one or more elements M selected from Zr, Ti, and Nb M Mass ratio W M / W Hf A compound of element M is further added so that the content of the compound of element M is within the range of 0.2% to 5.0%. Examples of the compound of element M include compounds of element M selected from the group consisting of halides, halites, hypohalites, halogen acid salts, perhalites, inorganic acid salts, organic acid salts, alkoxides, and complexes of element M. As the compound of element M, it is preferable to use an alkoxide having 5 or less carbon atoms. The atmosphere during the addition is preferably a non-oxidizing atmosphere, and in this embodiment, a nitrogen atmosphere is used. Furthermore, the temperature of the alcohol when the hafnium compound and the compound of element M are added is preferably within the range of 5°C or higher and 40°C or lower.

[0036] In the reflux step S02, the solvent to which the hafnium compound and the compound of element M have been added is heated with stirring to reflux. The heating temperature in this reflux step S02 is preferably within a range of 80° C. to 200° C. The holding time at the heating temperature is preferably within a range of 0.5 hours to 5 hours. When a stabilizer is added, it is preferable to carry out a stabilizer addition step S05 before the reflux step S02.

[0037] In addition, when polyalcohol is added, it is preferable to carry out a polyalcohol adding step S04 after this refluxing step S02. In this polyalcohol addition step S04, the solvent that has been subjected to the reflux step S02 is cooled to room temperature (for example, in the range of 20°C or higher and 30°C or lower), and then a polyalcohol having one or more ether groups in the molecule is added and mixed by stirring.

[0038] In the solvent addition step S03, alcohol as a solvent is added to adjust the composition of the hafnium compound-containing sol-gel liquid.

[0039] The hafnium compound-containing sol-gel solution of this embodiment is produced by the above steps.

[0040] The hafnia-containing film of this embodiment is formed using the hafnium compound-containing sol-gel solution of this embodiment described above. The hafnia-containing film of this embodiment contains hafnia (HfO2) and one or more elements M selected from Zr, Ti, and Nb, and the content W of the HfO2 HfO2 and the content W of the element M M Mass ratio W M / W HfO2 is set to be within the range of 0.05% to 5.0%. In addition, the mass ratio W M / W HfO2 is preferably set to 3.0% or less, and more preferably set to 1.0% or less.

[0041] Next, the method for producing the hafnia-containing film according to the present embodiment will be described with reference to the flow chart of FIG.

[0042] As shown in FIG. 2, the method for producing a hafnia-containing film according to this embodiment includes a hafnium compound-containing sol-gel liquid application step S11 in which the hafnium compound-containing sol-gel liquid according to this embodiment is applied to the surface of a substrate, a drying step S12 in which the applied hafnium compound-containing sol-gel liquid is dried to form a hafnium compound-containing gel film, and a firing step S13 in which the hafnium compound-containing gel film is fired to form a hafnium-containing film.

[0043] In this embodiment, the substrate on which the hafnia-containing film is formed is a metal substrate, but is not limited to metal. Preferably, the substrate has a hydrophilic coating such as an oxide film formed on its surface. Furthermore, the surface of the substrate may be roughened by blasting or etching. The substrate may be a single metal such as aluminum, titanium, iron, nickel, zinc, magnesium, or copper, or an alloy or oxide thereof, an elemental semiconductor such as silicon or gallium, or a compound semiconductor such as silicon oxide, silicon nitride, silicon carbide, indium phosphide, gallium nitride, gallium arsenide, or gallium oxide.

[0044] In the hafnium compound-containing sol-gel liquid application step S11, the hafnium compound-containing sol-gel liquid of this embodiment is applied to the surface of the substrate. At this time, there is no particular limitation on the application method, and a spray method, a dipping method, or the like may be used, but in this embodiment, the hafnium compound-containing sol-gel liquid is applied by spin coating. Here, when the hafnium compound-containing sol-gel liquid of this embodiment contains a polyalcohol having one or more ether groups in the molecule as a wetting improver, it becomes possible to apply it uniformly to the surface of a hydrophilic substrate.

[0045] In the drying step S12, the hafnium compound-containing sol-gel solution applied to the surface of the substrate is dried to form a hafnium compound-containing gel film. Here, when the hafnium compound-containing sol-gel solution of this embodiment uses a lower alcohol having 5 or less carbon atoms as a solvent, the solvent can be evaporated relatively easily in the drying step S12. The heating conditions in this drying step S12 are preferably air or oxygen atmosphere, heating temperature in the range of 100° C. to 400° C., and holding time at the heating temperature in the range of 0.5 to 10 minutes. The hafnium compound-containing sol-gel liquid application step S11 and the drying step S12 may be repeated to form a hafnium compound-containing gel film of a predetermined thickness.

[0046] In the firing step S13, the hafnium compound-containing gel film is heated and fired to form a hafnia-containing film. The heating conditions in this firing step S13 are preferably air or oxygen atmosphere, heating temperature in the range of 400° C. to 1000° C., and holding time at the heating temperature in the range of 0.5 to 10 minutes. When the hafnium compound-containing sol-gel liquid applying step S11 and the drying step S12 are repeatedly performed, the baking step S13 may be performed after each drying step S12.

[0047] Through the above-described steps, the hafnia-containing film of this embodiment is produced on the surface of the substrate.

[0048] The hafnium compound-containing sol-gel solution of this embodiment configured as described above contains a hafnium compound that serves as a hafnia source, and has a metal component with a Hf content of W Hf and the content W of the element M M Mass ratio W M / W Hf Since the content of M is within the range of 0.2% or more and 5.0% or less, one or more elements M selected from Zr, Ti, and Nb crystallize to become seed crystals, which promotes the crystallization of Hf, making it possible to form a hafnia-containing film having a high degree of crystallinity and excellent etching resistance.

[0049] In the hafnium compound-containing sol-gel solution of this embodiment, if the alcohol used as the solvent is a lower alcohol having 5 or less carbon atoms, the solvent can be evaporated relatively easily in the drying step S12, making it possible to stably form a hafnium-containing film.

[0050] In the hafnium compound-containing sol-gel solution of this embodiment, when the content of the hafnium compound is within the range of 0.05 wt % to 10 wt %, a hafnia-containing film can be reliably formed.

[0051] In the hafnium compound-containing sol-gel liquid of this embodiment, when a polyalcohol having one or more ether groups in the molecule is contained as a wettability improver, the polyalcohol has a high affinity for hydrophilic surfaces and also has a high affinity with the hafnium compound-containing sol-gel liquid, making it possible to uniformly apply the hafnium compound-containing sol-gel liquid to the hydrophilic substrate surface.

[0052] In the hafnium compound-containing sol-gel liquid of this embodiment, when the content of the polyalcohol is within the range of 0.05 wt% or more and 20 wt% or less, the hafnium compound-containing sol-gel liquid can be applied more uniformly to the hydrophilic substrate surface.

[0053] When the hafnium compound-containing sol-gel liquid of this embodiment further contains a stabilizer, deterioration of the hafnium compound-containing sol-gel liquid can be suppressed, making the hafnium compound-containing sol-gel liquid easier to handle.

[0054] The hafnia-containing film of this embodiment contains hafnia (HfO2) and one or more elements M selected from Zr, Ti, and Nb, and the content W of HfO2 is HfO2 and the content W of one or more elements M selected from Zr, Ti, and Nb. M Mass ratio W M / W HfO2 Since the content of Zr is within the range of 0.05% or more and 5.0% or less, crystallization is promoted by one or more elements M selected from Zr, Ti, and Nb, resulting in a high degree of crystallization and excellent etching resistance.

[0055] Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical idea of ​​the invention. [Example]

[0056] The results of confirmation experiments conducted to confirm the effectiveness of the present invention will be described below.

[0057] Hafnium butoxide was used as the hafnium raw material, 1-butanol was used as the solvent, and acetylacetone was used as the stabilizer. Zirconium butoxide, titanium isopropoxide, and niobium ethoxide were also used, with Zr, Ti, and Nb added in the ratios shown in Table 1. These were mixed and refluxed for 1 hour, then filtered to synthesize a sol-gel solution containing a hafnium compound. Acetylacetone was used as the stabilizer, and diethylene glycol was used as the wettability improver.

[0058] The obtained hafnium compound-containing sol-gel liquid was dropped onto a silicon substrate and applied by spin coating. The silicon substrate coated with the hafnium compound-containing sol-gel liquid was heated to 100 to 250°C using a hot plate, and then placed in a muffle furnace at 600°C and heated for 5 minutes to form a hafnia-containing film.

[0059] The hafnium compound-containing sol-gel solutions and hafnia-containing films of the inventive and comparative examples were evaluated as follows.

[0060] (Zr, Ti, Nb in sol-gel solution containing hafnium compounds) 1 g of the sol-gel liquid containing the hafnium compound was taken and added to a mixed solution of 60 wt % nitric acid (2.5 mL) and 50 wt % hydrofluoric acid (2.5 mL). The mixed solution was heated and diluted with ultrapure water to 50 mL, and the contents of Hf, Zr, Ti, and Nb in the solution were measured using ICP-OES, and the content ratios of Zr, Ti, and Nb when Hf was 100 wt% were calculated.

[0061] (Zr, Ti, Nb in hafnia-containing films) A silicon substrate on which a hafnia-containing film was formed was immersed in 1 wt % hydrofluoric acid, and heating was continued until the hafnia-containing film was dissolved, after which the silicon substrate was taken out and used as a measurement solution. This measurement solution was diluted appropriately, and the amounts of Hf, Zr, Ti, and Nb dissolved were determined by ICP-OES. After converting the Hf to be entirely HfO2, the content ratios of Zr, Ti, and Nb to HfO2 were determined.

[0062] (etching rate) A silicon substrate on which a hafnia-containing film had been formed, the thickness of which had been measured in advance, was immersed in a stirred 1 wt% HF solution at 25°C. The film thickness was measured after a certain period of immersion, and the etching rate was calculated from the change in film thickness before and after immersion. The film thickness of the hafnia-containing film was measured using an ellipsometer (UVISEL-HR320 AGMS, manufactured by Horiba, Ltd.). Measurements were taken at three locations, and the average value was used as the film thickness. An etching rate of 2 nm / min or less was evaluated as "good", and an etching rate of more than 2 nm / min was evaluated as "poor".

[0063] [Table 1]

[0064] In Comparative Example 1, the Hf content W Hf and the content W of one or more elements M selected from Zr, Ti, and Nb M Mass ratio W M / W Hf The content of element M was 0.01%, and the etching rate was evaluated as "x." This is presumably because the content of element M was so small that the crystallization of the hafnia-containing film was not promoted.

[0065] In Comparative Example 2, the Hf content W Hf and the content W of one or more elements M selected from Zr, Ti, and Nb M Mass ratio W M / W Hf The etching rate was evaluated as "x". This is presumably because the content of element M was high, and the parts of the hafnia-containing film where element M was present were locally etched, resulting in a thinning of the hafnia-containing film.

[0066] In contrast, in Inventive Example 1-9, the Hf content W Hf and the content W of one or more elements M selected from Zr, Ti, and Nb M Mass ratio W M / W Hf The hafnia content W of HfO2 is in the range of 0.2% to 5.0%. HfO2 and the content W of one or more elements M selected from Zr, Ti, and Nb M Mass ratio W M / W HfO2 was in the range of 0.05% or more and 5.0% or less. In addition, the etching rate of the formed hafnia-containing film was evaluated as "Good." This is presumably because the element M sufficiently promoted the crystallization of the hafnia-containing film.

[0067] From the above, it has been confirmed that the present invention can provide a hafnium compound-containing sol-gel liquid capable of forming a hafnia-containing film having particularly excellent etching resistance, and a hafnia-containing film formed using this hafnium compound-containing sol-gel liquid.

Claims

1. A hafnium compound-containing sol-gel solution containing an alcohol as a solvent and a hafnium compound as a hafnia source, It contains one or more elements M selected from Zr, Ti, and Nb, and the content W of Hf as a metal component Ｈｆ and the content W of the element M Ｍ Mass ratio W Ｍ / W Ｈｆ 1. A sol-gel solution containing a hafnium compound, wherein the element M is in the range of 0.2% or more and 1.0% or less, and the element M includes Zr.

2. 2. The hafnium compound-containing sol-gel solution according to claim 1, wherein the alcohol used as the solvent is a lower alcohol having 5 or less carbon atoms.

3. 3. The hafnium compound-containing sol-gel solution according to claim 1, wherein the content of the hafnium compound is in the range of 0.05 wt % to 10 wt %.

4. 4. The hafnium compound-containing sol-gel solution according to claim 1, further comprising a polyalcohol having one or more ether groups in the molecule as a wettability improving agent.

5. 5. The hafnium compound-containing sol-gel solution according to claim 4, wherein the content of the polyalcohol is in the range of 0.05 wt % to 20 wt %.

6. The hafnium compound-containing sol-gel solution according to any one of claims 1 to 5, further comprising a stabilizer.

7. Hafnia (HfO ２ ) and one or more elements M selected from Zr, Ti, and Nb, The HfO ２ Content of W ＨｆＯ２ and the content W of the element M Ｍ Mass ratio W Ｍ / W ＨｆＯ２ 1. A hafnia-containing film, characterized in that the element M is in the range of 0.05% or more and 1.0% or less, and the element M includes Zr.

Images