Storage method for gas-filled containers and hydrogen halogens

Abstract

This provides a gas-filled container that is less susceptible to corrosion caused by hydrogen halides containing water. [Solution] The gas-filled container is made by filling the container with hydrogen halide containing water. The container comprises a cylinder containing hydrogen halide and a valve made of nickel-based superalloy. The nickel-based superalloy contains carbon in an amount greater than 0% by mass and less than 0.03% by mass, silicon in an amount greater than 0% by mass and less than 0.5% by mass, manganese in an amount greater than 0% by mass and less than 1.0% by mass, iron in an amount of 0.5% by mass and less than 8.0% by mass, chromium in an amount of 16.0% by mass and less than 25.0% by mass, molybdenum in an amount of 10.0% by mass and less than 16.0% by mass, tungsten in an amount of 1.0% by mass and less than 5.0% by mass, sulfur in an amount of 0.0050% by mass and less than 0.030% by mass, phosphorus in an amount of 0.0050% by mass and less than 0.030% by mass and nitrogen in an amount of 0.030% by mass and less than 0.030% by mass, with the remainder being nickel and unavoidable impurities.

Description

Technical Field

[0001] The present disclosure relates to a gas-filled container and a method for storing hydrogen halide.

Background Art

[0002] In order to perform fine processing stably in dry etching, it is required that the dry etching gas be of high purity (for example, 99.9% by volume or more). Further, since the dry etching gas is stored until use in a filled state in a filling container, it is necessary to maintain high purity over a long period in the filling container. Hydrogen halide used as a dry etching gas for semiconductor manufacturing is liable to dissolve in water, and an aqueous solution of hydrogen halide becomes a hydrohalic acid and dissolves various metals. That is, it is considered that the cause of the purity deterioration of hydrogen halide is trace water in the filling container or trace water in hydrogen halide. Since hydrogen halide containing water promotes corrosion of the inner surface of the filling container, it is considered that the purity of hydrogen halide enclosed in the filling container deteriorates, but it is extremely difficult to completely remove water from the filling container or hydrogen halide.

[0003] Under such circumstances, at present, it is required that hydrogen halide has extremely few impurities, and particularly, strict restrictions on the amount of metal impurities are on the order of volume ppm. Since manganese steel or the like used as a material for a general filling container undergoes corrosion due to the above reasons, it is not suitable as a material for a filling container handling hydrogen halide for semiconductor manufacturing. Furthermore, when hydrogen halide is stored in a filling container for a long period or used intermittently, the amount of metal impurities in the hydrogen halide gas tends to increase, and it is difficult to suppress the amount of metal impurities in the hydrogen halide gas to several volume ppm or less. Therefore, as a material for a filling container for hydrogen halide gas and members constituting a system for supplying hydrogen halide gas, it is preferable to use austenitic stainless steel typified by SUS316L in order to suppress deterioration of the purity of hydrogen halide due to corrosion. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-60307 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] For example, Patent Document 1 discloses an austenitic stainless steel that is resistant to corrosion by hydrogen halides. However, if the hydrogen halide contains water, corrosion may occur even in austenitic stainless steel. In particular, the valves of the filling container may come into contact with the atmosphere, making them more susceptible to corrosion by hydrogen halides than other parts. As a result, the purity of the hydrogen halide sealed in the filling container may decrease during storage. The object of this disclosure is to provide a gas-filled container that is less susceptible to corrosion caused by water-containing hydrogen halides, and a method for storing hydrogen halides. [Means for solving the problem]

[0006] To solve the aforementioned problems, one aspect of the present disclosure is as follows [1] to [7]. [1] A gas-filled container in which hydrogen halide is filled into the container, The aforementioned hydrogen halide contains water, The filling container comprises a cylinder containing the hydrogen halogenate and a valve that opens and closes a flow path for the hydrogen halogenate inside the cylinder to flow to the outside. The material of at least a portion of the valve that comes into contact with the hydrogen halide is a nickel-based superalloy. The nickel-based superalloy contains carbon in an amount exceeding 0% by mass but less than 0.03% by mass, silicon in an amount exceeding 0% by mass but less than 0.5% by mass, manganese in an amount exceeding 0% by mass but less than 1.0% by mass, iron in an amount between 0.5% by mass and less than 8.0% by mass, chromium in an amount between 16.0% by mass and less than 25.0% by mass, molybdenum in an amount between 10.0% by mass and less than 16.0% by mass, tungsten in an amount between 1.0% by mass and less than 5.0% by mass, sulfur in an amount of less than 0.0050% by mass, phosphorus in an amount of less than 0.030% by mass, oxygen in an amount of less than 0.0050% by mass, and nitrogen in an amount of less than 0.030% by mass, with the remainder being nickel and unavoidable impurities, in a gas-filled container.

[0007] [2] The gas-filled container according to [1], wherein the water content of the hydrogen halide is 10 ppb or more and 10 ppm or less by volume. [3] The nickel-based superalloy further contains at least one of the following: copper in an amount greater than 0% by mass and less than 1.0% by mass; cobalt in an amount greater than 0% by mass and less than 5.0% by mass; titanium in an amount greater than 0% by mass and less than 0.50% by mass; aluminum in an amount greater than 0% by mass and less than 0.50% by mass; niobium in an amount greater than 0% by mass and less than 0.50% by mass; vanadium in an amount greater than 0% by mass and less than 0.50% by mass; boron in an amount greater than 0% by mass and less than 0.03% by mass; zirconium in an amount greater than 0% by mass and less than 0.10% by mass; calcium in an amount greater than 0% by mass and less than 0.030% by mass; and magnesium in an amount greater than 0% by mass and less than 0.030% by mass. [1] or [2]

[0008] [4] A gas-filled container according to any one of the items [1] to [3], wherein the purity of the hydrogen halide is 99.99% by volume or higher. [5] A gas-filled container according to any one of the following [1] to [4], wherein the hydrogen halide is at least one of hydrogen fluoride, hydrogen chloride, and hydrogen bromide.

[0009] [6] A method for storing hydrogen halides, comprising filling hydrogen halides into a filled container and storing them, The aforementioned hydrogen halide contains water, The filling container comprises a cylinder containing the hydrogen halogenate and a valve that opens and closes a flow path for the hydrogen halogenate inside the cylinder to flow to the outside. The material of at least a portion of the valve that comes into contact with the hydrogen halide is a nickel-based superalloy. A method for storing hydrogen halides, wherein the nickel-based superalloy contains carbon in an amount exceeding 0% by mass but less than 0.03% by mass, silicon in an amount exceeding 0% by mass but less than 0.5% by mass, manganese in an amount exceeding 0% by mass but less than 1.0% by mass, iron in an amount of 0.5% by mass or more but less than 8.0% by mass, chromium in an amount of 16.0% by mass or more but less than 25.0% by mass, molybdenum in an amount of 10.0% by mass or more but less than 16.0% by mass, tungsten in an amount of 1.0% by mass or more but less than 5.0% by mass, sulfur in an amount of 0.0050% by mass or less, phosphorus in an amount of 0.030% by mass or less, oxygen in an amount of 0.0050% by mass or less, and nitrogen in an amount of 0.030% by mass or less, with the remainder being nickel and unavoidable impurities. [7] The method for storing hydrogen halogens according to [6], wherein the water content of the hydrogen halogen is 10 ppb or more and 10 ppm or less by volume. [Effects of the Invention]

[0010] The gas-filled container and hydrogen halide storage method described herein are less likely to cause corrosion of the container due to hydrogen halide containing water. [Brief explanation of the drawing]

[0011] [Figure 1] This figure illustrates an example of the configuration of an apparatus for evaluating the performance of test pieces in the examples and comparative examples. [Modes for carrying out the invention]

[0012] One embodiment of the present disclosure is described below. This embodiment is merely an example of the present disclosure, and the disclosure is not limited to this embodiment. Furthermore, various modifications or improvements can be made to this embodiment, and such modified or improved forms may also be included in the present disclosure.

[0013] The gas-filled container according to this embodiment is a gas-filled container in which hydrogen halogen is filled, wherein the hydrogen halogen contains water, and the container comprises a cylinder containing the hydrogen halogen and a valve that opens and closes a flow path for the hydrogen halogen inside the cylinder to flow to the outside, wherein at least a portion of the valve that comes into contact with the hydrogen halogen is made of a nickel-based superalloy, and the nickel-based superalloy is made of carbon exceeding 0% by mass and 0.03% by mass or less, and exceeding 0% by mass. It contains 5% by mass or less of silicon, manganese exceeding 0% by mass and 1.0% by mass or less, iron between 0.5% by mass and 8.0% by mass, chromium between 16.0% by mass and 25.0% by mass, molybdenum between 10.0% by mass and 16.0% by mass, tungsten between 1.0% by mass and 5.0% by mass, sulfur between 0.0050% by mass or less, phosphorus between 0.030% by mass or less, oxygen between 0.0050% by mass or less, and nitrogen between 0.030% by mass or less, with the remainder being nickel and unavoidable impurities.

[0014] Furthermore, the hydrogen halide storage method according to this embodiment is a method for storing hydrogen halide by filling a filled container with hydrogen halide, wherein the hydrogen halide contains water, and the filled container comprises a cylinder containing the hydrogen halide and a valve that opens and closes a flow path for the hydrogen halide inside the cylinder to flow to the outside, wherein at least a portion of the valve that comes into contact with the hydrogen halide is made of a nickel-based superalloy, and the nickel-based superalloy is made of carbon exceeding 0% by mass and 0.03% by mass or less, 0 mass It contains silicon in an amount exceeding 0.5% by mass or less, manganese in an amount exceeding 0% by mass or less than 1.0% by mass, iron in an amount between 0.5% by mass and 8.0% by mass, chromium in an amount between 16.0% by mass and 25.0% by mass, molybdenum in an amount between 10.0% by mass and 16.0% by mass, tungsten in an amount between 1.0% by mass and 5.0% by mass, sulfur in an amount of 0.0050% by mass or less, phosphorus in an amount of 0.030% by mass or less, oxygen in an amount of 0.0050% by mass or less, and nitrogen in an amount of 0.030% by mass or less, with the remainder being nickel and unavoidable impurities.

[0015] The cylinder included in the filling container is less likely to corrode because it comes into contact with hydrogen halide having a low water (H2O) content. However, since the valve included in the filling container may come into contact with the atmosphere, corrosion due to contact with hydrogen halide is likely to occur even when the water content of the hydrogen halide is low. In the gas-filled filling container according to the present embodiment and the method for storing hydrogen halide according to the present embodiment, since at least a part of the material of the portion of the valve of the filling container that comes into contact with hydrogen halide is a nickel-based superalloy having the alloy composition, corrosion of the filling container is unlikely to occur even when it comes into contact with hydrogen halide containing water (particularly, corrosion of the valve is unlikely to occur). Therefore, according to the gas-filled filling container according to the present embodiment or the method for storing hydrogen halide according to the present embodiment, even if the gas-filled filling container is stored for a long period of time, the purity of the filled hydrogen halide is unlikely to decrease. Thus, in the case of a gas-filled filling container filled with high-purity hydrogen halide, high purity is likely to be maintained even after long-term storage. Regarding the nickel-based superalloy according to the present embodiment, the mass reduction rate before and after exposure to hydrogen bromide in Example 1 described later may be 5.0 mass% or less, may be 4.0 mass% or less, or may be 3.0 mass% or less.

[0016] The alloy components and alloy composition of the nickel-based superalloy will be described in detail below. [Carbon: More than 0 mass% and 0.03 mass% or less] Carbon (C) contributes to solid solution strengthening and has the effect of increasing the alloy strength. In addition, carbon combines with chromium (Cr), titanium (Ti), aluminum (Al), niobium (Nb), vanadium (V), tungsten (W), molybdenum (Mo), etc. to form various carbides. Among these carbides, those having a high solid solution temperature (for example, niobium carbide, titanium carbide, vanadium carbide) suppress the coarsening growth of crystal grains at high temperatures due to the pinning effect, and thus contribute to the improvement of the hot workability of the nickel-based superalloy. Further, for example, chromium carbide, molybdenum carbide, and tungsten carbide precipitate at grain boundaries to strengthen the grain boundaries, and thus contribute to the improvement of the mechanical properties of the nickel-based superalloy.

[0017] If the carbon content in the nickel-based superalloy exceeds 0% by mass and is 0.03% by mass or less, segregation of carbides and the like is less likely to cause non-uniformity of the structure and precipitation of grain boundary carbides, so the nickel-based superalloy is less likely to corrode, and the hot workability and mechanical properties of the nickel-based superalloy are good. The carbon content is preferably more than 0% by mass and 0.02% by mass or less.

[0018] [Silicon: more than 0% by mass and 0.5% by mass or less] Silicon (Si) contributes to deoxidation and is effective in reducing oxide-based inclusions in the nickel-based superalloy. Also, if the silicon content is 0.5% by mass or less, it is difficult to form local low melting point parts in the nickel-based superalloy, and the hot workability of the nickel-based superalloy is good.

[0019] [Manganese: more than 0% by mass and 1.0% by mass or less] Manganese (Mn) contributes to deoxidation and is effective in reducing oxide-based inclusions in the nickel-based superalloy. Also, if the manganese content is 1.0% by mass or less, it is difficult to form sulfides, and embrittlement of the nickel-based superalloy at high temperatures is less likely to occur. Furthermore, if the manganese content is 1.0% by mass or less, corrosion of the nickel-based superalloy due to the influence of sulfides is suppressed. The manganese content is preferably more than 0% by mass and 0.8% by mass or less.

[0020] [Iron: 0.5% by mass or more and 8.0% by mass or less] Iron (Fe) dissolves in the austenite phase which is the matrix phase, so if it is in a small amount, the nickel-based superalloy is not likely to corrode easily, and the influence on the strength and workability of the nickel-based superalloy is also less likely to occur. Also, since iron is a component mixed in by the selection of raw materials during the production of the nickel-based superalloy, depending on the selection of raw materials, although the iron content may increase, it leads to a reduction in the cost of raw materials. The lower limit value of the iron content is preferably 1.0% by mass or more, and the upper limit value is preferably 7.0% by mass or less. And the iron content is preferably 1.0% by mass or more and 7.0% by mass or less.

[0021] [Chromium: 16.0% by mass or more, 25.0% by mass or less] Chromium is an important element in preventing corrosion and oxidation of nickel-based superalloys because it forms a protective oxide film containing chromium oxide (Cr2O3). Chromium is an element that stabilizes ferrite, and excessive addition may destabilize austenite, promoting the formation of brittle phases such as the sigma phase and Laves phase, potentially leading to a decrease in mechanical properties such as hot workability, strength properties, and impact properties. However, if the chromium content is between 16.0% by mass and 25.0% by mass, a decrease in the mechanical properties of the nickel-based superalloy is less likely to occur. Preferably, the lower limit of the chromium content is 18.0% by mass or more, and the upper limit is 24.0% by mass or less. In particular, the chromium content is preferably between 18.0% by mass and 24.0% by mass.

[0022] [Molybdenum: 10.0% by mass or more, 16.0% by mass or less] Molybdenum is a solid solution strengthening element that strengthens nickel-based superalloys by dissolving in the austenite phase, which has an FCC structure and is the matrix phase of nickel-based superalloys. It also strengthens the protective oxide film containing chromium oxide (Cr2O3), making nickel-based superalloys more resistant to corrosion.

[0023] Excessive addition of molybdenum can destabilize austenite, promoting the formation of brittle phases such as the sigma phase and the Raves phase, which may lead to a decrease in the hot workability and mechanical properties of nickel-based superalloys. However, if the molybdenum content is between 10.0% by mass and 16.0% by mass, a decrease in the hot workability and mechanical properties of nickel-based superalloys is less likely to occur. The molybdenum content is preferably between 11.0% by mass and 16.0% by mass.

[0024] [Tungsten: 1.0% by mass or more, up to 5.0% by mass] Tungsten is a solid solution strengthening element that dissolves in the matrix phase of nickel-based superalloys, distorting the crystal lattice and increasing the lattice constant. Similar to molybdenum, it also has the effect of making nickel-based superalloys more resistant to corrosion. Excessive addition of tungsten can promote the formation of σ and μ phases, potentially reducing the toughness of the nickel-based superalloy; therefore, the tungsten content should be between 1.0 mass% and 5.0 mass%.

[0025] [Sulfur: 0.0050% by mass or less] Since sulfur (S) is an impurity element, it is desirable to keep the sulfur content low. If the sulfur content is 0.0050 mass% or less, the workability of the nickel-based superalloy will be good, and the nickel-based superalloy will be less susceptible to corrosion. The lower limit of the sulfur content may be greater than 0 mass%, but since sulfur is an impurity element, the sulfur content may be 0 mass%. In other words, the sulfur content may be between 0 mass% and 0.0050 mass%, or between 0 mass% and 0.0050 mass%.

[0026] [Phosphorus: 0.030% by mass or less] Since phosphorus (P) is an impurity element, it is desirable to keep the phosphorus content low. If the phosphorus content is 0.030 mass% or less, the processability of the nickel-based superalloy will be good. The lower limit of the phosphorus content may be greater than 0 mass%, but since phosphorus is an impurity element, the phosphorus content may be 0 mass%. In other words, the phosphorus content may be between 0 mass% and 0.030 mass%, or between 0 mass% and 0.030 mass%.

[0027] [Oxygen: 0.0050% by mass or less] Since oxygen (O) is an impurity element, it is desirable to keep the oxygen content low. If the oxygen content is 0.0050 mass% or less, there will be fewer oxide inclusions and the purity of the nickel-based superalloy will be high. The lower limit of the oxygen content may be greater than 0 mass%, but since oxygen is an impurity element, the oxygen content may be 0 mass%. In other words, the oxygen content may be between 0 mass% and 0.0050 mass%, or between 0 mass% and 0.0050 mass%.

[0028] [Nitrogen: 0.030% by mass or less] Nitrogen (N) contributes to solid solution strengthening and enhances alloy strength. Furthermore, if the nitrogen content is 0.030 mass% or less, even if chromium nitride precipitates, the nickel-based superalloy will be less susceptible to corrosion, and the decrease in toughness of the nickel-based superalloy will be suppressed. The lower limit of the nitrogen content may be greater than 0 mass%, but since nitrogen is an impurity element, the nitrogen content may be 0 mass%. In other words, the nitrogen content may be between 0 mass% and 0.030 mass%, or between 0 mass% and 0.030 mass%.

[0029] The nickel-based superalloy in the gas-filled container according to this embodiment, and the nickel-based superalloy in the hydrogen halide storage method according to this embodiment, may further contain at least one of the following: copper in an amount exceeding 0% by mass and up to 1.0% by mass; cobalt in an amount exceeding 0% by mass and up to 5.0% by mass; titanium in an amount exceeding 0% by mass and up to 0.50% by mass; aluminum in an amount exceeding 0% by mass and up to 0.50% by mass; niobium in an amount exceeding 0% by mass and up to 0.50% by mass; vanadium in an amount exceeding 0% by mass and up to 0.50% by mass; boron in an amount exceeding 0% by mass and up to 0.03% by mass; zirconium in an amount exceeding 0% by mass and up to 0.10% by mass; calcium in an amount exceeding 0% by mass and up to 0.030% by mass; and magnesium in an amount exceeding 0% by mass and up to 0.030% by mass.

[0030] [Copper: more than 0% by mass and less than 1.0% by mass] [Tantalum: Over 0% by mass, up to 0.5% by mass] Copper (Cu) and tantalum (Ta) have the effect of making nickel-based superalloys less susceptible to corrosion; therefore, at least one of copper and tantalum may be included in the nickel-based superalloy. If the copper content is 1.0 mass% or less and the tantalum content is 0.5 mass% or less, the hot workability and cost of the nickel-based superalloy are good.

[0031] [Cobalt: Over 0% by mass, up to 5.0% by mass] Cobalt (Co) enhances the strength of nickel-based superalloys through solid solution strengthening; therefore, cobalt may be included in nickel-based superalloys. If the cobalt content is 5.0% by mass or less, the cost of the nickel-based superalloy is favorable.

[0032] [Titanium: Over 0% by mass and 0.50% by mass or less] [Aluminum: Over 0% by mass, up to 0.50% by mass] [Niobium: more than 0% by mass and less than 0.50% by mass] [Vanadium: Over 0% by mass, up to 0.50% by mass] Titanium, aluminum, niobium, and vanadium are elements that combine with carbon and nitrogen to form carbides and nitrides with relatively high solid solution temperatures. Therefore, the addition of at least one of titanium, aluminum, niobium, and vanadium suppresses grain coarsening after solution heat treatment (pinning effect), contributing to improved high-temperature strength and hot forgeability of nickel-based superalloys.

[0033] Furthermore, while the formation of chromium, molybdenum, and tungsten carbides makes nickel-based superalloys more susceptible to corrosion, the addition of at least one of titanium, aluminum, niobium, and vanadium allows these to bond with carbon, thus making the nickel-based superalloys less prone to corrosion. Therefore, at least one of titanium, aluminum, niobium, and vanadium may be added to nickel-based superalloys. For titanium, aluminum, niobium, and vanadium, if their content is 0.50% by mass or less, coarse carbides and nitrides are less likely to form, resulting in good hot workability and toughness of the nickel-based superalloy.

[0034] For titanium, aluminum, niobium, and vanadium, the lower limit of their content is more preferably 0.07% by mass or more, and the upper limit is more preferably 0.30% by mass or less.

[0035] [Boron: more than 0% by mass and less than 0.03% by mass] [Zirconium: Over 0% by mass, up to 0.10% by mass] [Yttrium: more than 0% by mass and less than 0.10% by mass] Boron (B), yttrium (Y), and zirconium (Zr) are elements that contribute to improving the workability and mechanical strength of nickel-based superalloys by segregating at grain boundaries and strengthening them. Therefore, at least one of boron, yttrium, and zirconium may be added to nickel-based superalloys. If the boron content is greater than 0% by mass but less than or equal to 0.03% by mass, the yttrium content is greater than 0% by mass but less than or equal to 0.10% by mass, and the zirconium content is greater than 0% by mass but less than or equal to 0.10% by mass, excessive segregation at grain boundaries is less likely to occur, resulting in good ductility of the nickel-based superalloy.

[0036] [Calcium: Over 0% by mass, 0.030% by mass or less] [Magnesium: Over 0% by mass, up to 0.030% by mass] Calcium (Ca) and magnesium (Mg) improve the hot workability of nickel-based superalloys by stabilizing sulfur through the formation of sulfides. Therefore, at least one of calcium and magnesium may be added to nickel-based superalloys. If the calcium content is greater than 0% by mass but less than or equal to 0.030% by mass, and the magnesium content is greater than 0% by mass but less than or equal to 0.030% by mass, calcium and magnesium are less likely to concentrate at the grain boundaries, resulting in good hot workability, such as hot forging properties, of the nickel-based superalloy.

[0037] The nickel-based superalloy according to this embodiment can be obtained by melting and refining the raw materials necessary to obtain a predetermined alloy composition in, for example, an arc furnace, induction furnace, or vacuum induction furnace. Refining can be carried out using methods such as AOD (Argon-Oxygen-Decarburization) or VOD (Vacuum-Oxygen-Decarburization). The obtained ingot can be remelted one or more times by electroslag remelting (ESR) or vacuum arc remelting (VAR). This improves the cleanliness. Afterward, the molten metal is poured into a mold and solidified to form a steel ingot. Then, after being held in a predetermined temperature range for a predetermined time, the material for hot working according to this embodiment can be manufactured by hot forging or hot rolling.

[0038] [Filling container] The filled container in the gas-filled container according to this embodiment, and the filled container in the hydrogen halogen storage method according to this embodiment, comprise a cylinder and a valve. The cylinder is a component that contains hydrogen halogen. Preferably, this cylinder is a seamless, integrally molded container. Furthermore, the valve is a component that opens and closes the flow path that allows hydrogen halogens inside the cylinder to flow to the outside, and controls the flow of hydrogen halogens through the said flow path.

[0039] In the gas-filled container and the hydrogen halide storage method according to this embodiment, at least a portion of the valve that comes into contact with the hydrogen halide is made of a nickel-based superalloy, but the material of the cylinder is not particularly limited. The material of the cylinder may be the same nickel-based superalloy as the valve, or it may be made of another material.

[0040] [Hydrogen halide] In the gas-filled container and the hydrogen halide storage method according to this embodiment, the type of hydrogen halide is not particularly limited, but for example, the hydrogen halide may be at least one of hydrogen fluoride (HF), hydrogen chloride (HCl), and hydrogen bromide (HBr).

[0041] In the gas-filled container and the hydrogen halide storage method according to this embodiment, the purity of the hydrogen halide to be filled into the container (purity before filling into the container) is preferably 99.90% by volume or higher, more preferably 99.95% by volume or higher, and even more preferably 99.99% by volume or higher.

[0042] When dry etching is performed using hydrogen halide with a purity of 99.90% by volume or higher as the dry etching gas, the reproducibility of plasma behavior and etching performance tends to be good. There are no particular limitations on the method for measuring the purity of hydrogen halides, but for example, it can be measured by gas chromatography or Fourier transform infrared spectroscopy (FT-IR analysis).

[0043] Furthermore, in the gas-filled container and the hydrogen halide storage method according to this embodiment, the water content of the hydrogen halide is preferably 10 ppb or more and 10 ppm or less, more preferably 5 ppb or more and 5 ppm or less, and even more preferably 1 ppb or more and 1 ppm or less. If hydrogen halide with such a low water content is filled into the container, the container, including the valve and cylinder, is less likely to be corroded by the hydrogen halide, so the purity of the hydrogen halide is less likely to decrease, and high purity is more easily maintained even after long-term storage.

[0044] Furthermore, the lower limit of the water content of hydrogen halide is preferably 10 ppb or more, more preferably 5 ppb or more, and even more preferably 1 ppb or more. Moreover, the upper limit of the water content of hydrogen halide is preferably 10 ppm or less, more preferably 5 ppm or less, and even more preferably 1 ppm or less.

[0045] The method for filling a container with hydrogen halide is not particularly limited, but one example is to fill the container, which has been evacuated to create a reduced pressure inside, with hydrogen halide through a filling line that has been purged with an inert gas. Examples of inert gases include nitrogen gas (N2), argon (Ar), and helium (He).

[0046] The type of purging process is not particularly limited; batch purging, which involves filling the filling line with inert gas and then evacuating it, and flow purging, which involves continuously flowing inert gas through the filling line, can be used. The type of filling line is not particularly limited, but it may be composed of piping whose inner surface has been treated by passivation or electropolishing. [Examples]

[0047] The present disclosure will be further explained below with reference to examples and comparative examples. First, with reference to Figure 1, the configuration of the apparatus for evaluating the performance (corrosion resistance) of the test pieces of the examples and comparative examples will be described. The apparatus shown in Figure 1 comprises a gas cylinder 1 filled with hydrogen halogen gas, a mass flow controller 2 for controlling the flow rate of hydrogen halogen gas, a liquid 4 for adjusting the humidity of the hydrogen halogen gas mixture, a reaction chamber 3 for reacting the hydrogen halogen and the liquid 4, and a pressure gauge 5 for measuring the pressure inside the reaction chamber 3.

[0048] Furthermore, the apparatus shown in Figure 1 includes, downstream of the reaction chamber 3, a reaction chamber 6 for exposing the test piece 10 to hydrogen halide, a pressure gauge 7 for measuring the pressure inside the reaction chamber 6, a thermometer 8 for measuring the temperature inside the reaction chamber 6, and a heating device 9 for heating the mixed gas and the test piece 10 inside the reaction chamber 6.

[0049] Furthermore, the apparatus shown in Figure 1 includes, downstream of the reaction chamber 6, a moisture meter 11 for measuring the humidity of the mixed gas, a decontamination device 12 for removing harmful substances from the mixed gas before exhausting it to the outside, and a vacuum pump 13 for reducing the pressure within the system. These are connected by piping, as shown in Figure 1.

[0050] When evaluating the corrosion resistance of the test piece 10 using the apparatus shown in Figure 1, first, the test piece 10 is placed in the reaction chamber 6, and then the hydrogen halogen gas in the gas cylinder 1 is sent to the reaction chamber 3 by the mass flow controller 2. The reaction chamber 3 contains water or hydrohalogen acid as liquid 4 for adjusting humidity, and the humidity of the mixed gas supplied to the reaction chamber 6 can be arbitrarily controlled by bubbling the liquid 4 with hydrogen halogen gas whose flow rate is adjusted by the mass flow controller 2. If the reaction chamber 3 is not used, hydrogen halogen gas with 0% humidity can be supplied to the reaction chamber 6.

[0051] Reaction chambers 3 and 6 are not particularly limited as long as they are made of a material resistant to hydrogen halide gas and hydrohalogen acids, but examples of materials include fluororesins (e.g., PFA, PTFE, PVDF, PCTFE). Similarly, the piping connected to reaction chambers 3 and 6 is not particularly limited as long as it is made of a material resistant to hydrogen halide gas and hydrohalogen acids, but it is preferable that it has a structure that can withstand a predetermined pressure.

[0052] In the exposure step in which the test piece 10 is exposed to hydrogen halide, the temperature at which the test piece 10 reacts with the mixed gas can be determined by arbitrarily controlling the temperature inside the reaction chamber 6 using the heating device 9. The temperature at which the test piece 10 reacts with the mixed gas in the exposure step is not particularly limited, but considering the temperature in the actual operating environment, it is preferably 0°C to 80°C, more preferably 10°C to 70°C, and even more preferably 20°C to 60°C.

[0053] The pressure during the exposure process can be determined by arbitrarily controlling the pressure inside the reaction chamber 6 using the mass flow controller 2 and the valve attached to the reaction chamber 6. The pressure during the exposure process is not particularly limited, but considering the pressure in actual operating environments, it is preferably 1 Pa or more and 5 MPa or less, more preferably 10 Pa or more and 4 MPa or less, and even more preferably 100 Pa or more and 3 MPa or less.

[0054] The humidity of the mixed gas in the exposure process can be determined by arbitrarily controlling the humidity of the mixed gas in the reaction chamber 6 using the mass flow controller 2 and the moisture content meter 11. The humidity of the mixed gas in the exposure process is not particularly limited, but considering the humidity in the actual operating environment, it is preferable to have a humidity of 2500 ppm by volume or more in a humid environment.

[0055] While there are no particular limitations on the exposure time in the exposure process, it is preferable to have an exposure time of one week or more, considering the actual operating environment. The exposure time refers to the time from when the mixed gas is supplied to the reaction chamber 6 containing the test piece 10 until the mixed gas is exhausted to end the exposure. After the exposure is complete, the mixed gas is exhausted to the outside from the reaction chamber 6. However, the mixed gas is sent to a detoxification device 12 to remove harmful substances before being exhausted to the outside.

[0056] [Preparation of test pieces] Raw materials, formulated to have the specified components shown in Tables 1 and 2, were first melted in a vacuum induction heating furnace, and then secondarily melted in a vacuum arc remelting furnace. The cast steel after the second melting was hot forged and hot rolled to produce 10 mm thick steel, and then the steel plate, which was solution treated at 1200°C, was processed into test pieces measuring 15 mm in length, 15 mm in width, and 1 mm in thickness.

[0057] [Example 1] A metal test piece 10, used to evaluate corrosion resistance, was placed in a reaction chamber 6 (a PFA multi-purpose pressure-resistant jar manufactured by Savillex Corporation) equipped with a pressure gauge 7 and a thermometer 8. The test piece 10 was a plate-like shape measuring 15 mm in length, 15 mm in width, and 1 mm in thickness. The metal forming the test piece 10 was a nickel-based superalloy, and its alloy composition is shown in Table 1.

[0058] Furthermore, 50 mL of pure water was placed in reaction chamber 3 (a PFA multi-purpose pressure-resistant jar manufactured by Savillex) as liquid 4 to adjust the humidity of the hydrogen halide and water gas mixture. Reaction chamber 6 was heated using an oil bath, which is a heating device 9. Heating of reaction chamber 6 was continued until the temperature reading on thermometer 8 reached 40°C.

[0059] When the reading on thermometer 8 reached 40°C, hydrogen bromide (manufactured by Resonaq Corporation, purity 99.99% by volume or higher), whose flow rate was adjusted to 500 mL / min using mass flow controller 2 (digital mass flow controller SEC-N100 manufactured by Horiba STEC Co., Ltd.), was supplied to reaction chamber 3.

[0060] After closing the valve downstream of reaction chamber 3 to seal it, hydrogen bromide was supplied to reaction chamber 3 from gas cylinder 1, and the pure water in reaction chamber 3 was bubbled with hydrogen bromide. Hydrogen bromide was then continuously supplied to reaction chamber 3 until the pressure inside reaction chamber 3 reached 1 MPa. After supplying hydrogen bromide to the above pressure, the valve downstream of reaction chamber 3 was opened, and the mixed gas of water and hydrogen bromide was supplied from reaction chamber 3 to reaction chamber 6. The humidity of the mixed gas supplied to reaction chamber 6 was measured using a moisture content meter 11 (Techne Measuring Instruments Co., Ltd., Corrosive Gas Continuous Moisture Analyzer TMA-210), and it was confirmed that the water content of the mixed gas was 2500 ppm by volume or more.

[0061] The mixed gas was continuously supplied to the reaction chamber 6 for one hour. When water droplets began to precipitate inside the reaction chamber 6, the valve on the downstream side of the reaction chamber 6 was closed to seal the chamber 6, and the mixed gas was continued to be supplied to the reaction chamber 6 until the pressure inside the chamber 6 reached 1 MPa. After supplying the mixed gas to the above pressure, the valve on the upstream side of the reaction chamber 6 was closed to seal the chamber 6, and the temperature inside the reaction chamber 6 was maintained at 40°C while the test piece 10 was continuously exposed to the mixed gas for one week.

[0062] After the above exposure time had elapsed, the valve on the upstream side of reaction chamber 6 was opened, and the mixed gas inside reaction chamber 6 was absorbed by a filtration system (CLEANSE ZH acid gas filtration system, manufactured by Resonaq Corporation). Reaction chamber 6 was opened, and test piece 10 was recovered, and the mass of test piece 10 was measured. The amount of mass loss and the mass loss rate from the mass before exposure were then calculated. The results are shown in Table 1.

[0063] [Table 1]

[0064] [Comparative Examples 1-8] The test piece 10 was exposed to the mixed gas and evaluated in the same manner as in Example 1, except that the type of metal forming the test piece 10 was different. The results are shown in Table 1. The alloy compositions of the metals forming the test pieces 10 used in Comparative Examples 1, 2, and 4-8 are as shown in Table 1. The metal forming the test piece 10 used in Comparative Example 3 is nickel, as shown in Table 1.

[0065] As can be seen from the results of Example 1 and Comparative Examples 1 to 8, the nickel-based superalloy in the gas-filled container according to this embodiment, and the nickel-based superalloy in the hydrogen halide storage method according to this embodiment, were resistant to corrosion by hydrogen halides even in a humid environment where the moisture content in the mixed gas was 2500 vol ppm or more.

[0066] [Example 2] Two test pieces 10, identical to those used in Example 1, were prepared. The two test pieces 10 were placed inside a 10L capacity filling container. The two test pieces 10 were suspended in the space inside the filling container using a string and rod made of fluororesin. One test piece 10 was positioned 20 cm above the bottom of the filling container, and the other test piece 10 was positioned 60 cm above the bottom of the filling container.

[0067] After attaching a valve to the filling container, 10 kg of hydrogen bromide (manufactured by Resonaq Co., Ltd., purity 99.99% by volume or higher) was supplied into the filling container through the valve, and the valve was closed to seal the filling container. At this time, one test piece 10 was immersed in the liquid phase of hydrogen bromide, and the other test piece 10 was placed in the gas phase of hydrogen bromide. The water content of the hydrogen bromide was 2 ppm by volume.

[0068] Test piece 10 was continuously exposed to hydrogen bromide for one month at room temperature. After the above exposure time had elapsed, hydrogen bromide gas was discharged from the filled container. The valve was removed from the filled container and test piece 10 was recovered, and its mass was measured. The amount of mass loss and the mass loss rate from the mass before exposure were then calculated. The results are shown in Table 2.

[0069] [Example 3] In Example 2, the only difference was that hydrogen bromide was replaced with hydrogen fluoride (manufactured by Resonaq Corporation, purity 99.999% by volume or higher). Exposure of test piece 10 to hydrogen halides and evaluation of test piece 10 were carried out in the same manner as in Example 2. However, in Example 3, only test piece 10 immersed in the liquid phase of hydrogen fluoride was evaluated. The results are shown in Table 2. The water content of the hydrogen fluoride is 1 ppm by volume.

[0070] [Table 2]

[0071] As can be seen from the results of Example 2, the nickel-based superalloy in the gas-filled container according to this embodiment, and the nickel-based superalloy in the hydrogen halide storage method according to this embodiment, were resistant to corrosion by hydrogen halides even in a dry environment where the hydrogen bromide water content was 2 ppm by volume.

[0072] As can be seen from the results of Example 3, the nickel-based superalloy in the gas-filled container according to this embodiment, and the nickel-based superalloy in the hydrogen halide storage method according to this embodiment, were resistant to corrosion by hydrogen halides even in a dry environment where the water content of hydrogen fluoride was 1 ppm by volume.

Claims

1. A gas-filled container in which hydrogen halide is filled into the container, The aforementioned hydrogen halide contains water, The filling container comprises a cylinder containing the hydrogen halogenate and a valve that opens and closes a flow path for the hydrogen halogenate inside the cylinder to flow to the outside. The material of at least a portion of the valve that comes into contact with the hydrogen halide is a nickel-based superalloy. The nickel-based superalloy contains carbon in an amount exceeding 0% by mass and up to 0.03% by mass, silicon in an amount exceeding 0% by mass and up to 0.5% by mass, manganese in an amount exceeding 0% by mass and up to 1.0% by mass, iron in an amount of 0.5% by mass and up to 8.0% by mass, chromium in an amount of 16.0% by mass and up to 25.0% by mass, molybdenum in an amount of 10.0% by mass and up to 16.0% by mass, tungsten in an amount of 1.0% by mass and up to 5.0% by mass, sulfur in an amount of 0.0050% by mass and up to 0.030% by mass, phosphorus in an amount of 0.0050% by mass and up to 0.030% by mass, and nitrogen in an amount of 0.030% by mass and up to 0.030% by mass, with the remainder being nickel and unavoidable impurities, in a gas-filled container.

2. The gas-filled container according to claim 1, wherein the water content of the hydrogen halide is 10 ppb or more and 10 ppm or less by volume.

3. The gas-filled container according to claim 1 or claim 2, wherein the nickel-based superalloy further contains at least one of the following: copper in an amount exceeding 0% by mass and up to 1.0% by mass; cobalt in an amount exceeding 0% by mass and up to 5.0% by mass; titanium in an amount exceeding 0% by mass and up to 0.50% by mass; aluminum in an amount exceeding 0% by mass and up to 0.50% by mass; niobium in an amount exceeding 0% by mass and up to 0.50% by mass; vanadium in an amount exceeding 0% by mass and up to 0.50% by mass; boron in an amount exceeding 0% by mass and up to 0.03% by mass; zirconium in an amount exceeding 0% by mass and up to 0.10% by mass; calcium in an amount exceeding 0% by mass and up to 0.030% by mass; and magnesium in an amount exceeding 0% by mass and up to 0.030% by mass.

4. The gas-filled container according to claim 1 or claim 2, wherein the purity of the hydrogen halide is 99.99% by volume or more.

5. The gas-filled container according to claim 1 or claim 2, wherein the hydrogen halogen is at least one of hydrogen fluoride, hydrogen chloride, and hydrogen bromide.

6. A method for storing hydrogen halides, which involves filling hydrogen halides into a container and storing it there. The aforementioned hydrogen halide contains water, The filling container comprises a cylinder containing the hydrogen halogenate and a valve that opens and closes a flow path for the hydrogen halogenate inside the cylinder to flow to the outside. The material of at least a portion of the valve that comes into contact with the hydrogen halide is a nickel-based superalloy. A method for storing hydrogen halides, wherein the nickel-based superalloy contains carbon in an amount exceeding 0% by mass and up to 0.03% by mass, silicon in an amount exceeding 0% by mass and up to 0.5% by mass, manganese in an amount exceeding 0% by mass and up to 1.0% by mass, iron in an amount of 0.5% by mass and up to 8.0% by mass, chromium in an amount of 16.0% by mass and up to 25.0% by mass, molybdenum in an amount of 10.0% by mass and up to 16.0% by mass, tungsten in an amount of 1.0% by mass and up to 5.0% by mass, sulfur in an amount of 0.0050% by mass and up to 0.030% by mass, phosphorus in an amount of 0.0050% by mass and up to 0.030% by mass, and nitrogen in an amount of 0.030% by mass and up to 0.030% by mass, with the remainder being nickel and unavoidable impurities.

7. The method for storing hydrogen halogen according to claim 6, wherein the water content of the hydrogen halogen is 10 ppb or more and 10 ppm or less by volume.

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