Container filled with liquefied gas and method for manufacturing container filled with liquefied gas

Abstract

This liquefied gas-containing container (100) is configured so as to have a storage part (10) and liquefied gas (30) stored in the storage part (10), the storage part (10) having a metal film (20) on an inner surface (12), the metal film (20) having a fluoride passivation film (22) containing a metal fluoride, the storage part (10) having a gas (35) containing a gas phase (34) of the liquefied gas (30) and a liquid (33) containing a gas phase (34) of the liquefied gas (30), the fluoride passivation film (22) containing a metal fluoride on the metal film (20), and the gas phase (34) containing a gas phase (34) of the liquefied gas (30). The liquid (33) contains a liquid phase (32) of the liquefied gas (30), and further contains a nickel element and / or a copper element.

Description

Technical Field

[0001] The present invention relates to a container filled with liquefied gas and a method for manufacturing the container filled with liquefied gas. Background Art

[0002] Various developments have been made so far for containers containing liquefied gas. As such a technology, the technology described in Patent Document 1 is known. Patent Document 1 describes that corrosion resistance to halogen-based gases is improved by forming a fluoride passivation film on the surface of a metal material (claim 1 of Patent Document 1, inventive effects, etc.).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent document 1: Japanese Patent Application Laid-Open No. 02-263972. Summary of the invention

[0006] Problem that the invention aims to solve

[0007] However, the present inventors' research results indicate that the gas storage container using the metal material with the fluoride passivation film described in Patent Document 1 has room for improvement in suppressing the performance fluctuation of liquefied gas.

[0008] Solutions for solving problems

[0009] After further research, the inventors found that by using a container with a fluoride passivation film formed on a metal film and making the liquid in the container contain nickel and / or copper elements, the difference in gas composition between the initial liquefied gas before the container is opened and the liquefied gas after the gas starts to be released can be made extremely small. As a result, changes in gas performance can be suppressed, thereby completing the present invention.

[0010] According to one aspect of the present invention, there are provided the following container containing liquefied gas and a method for manufacturing the container containing liquefied gas.

[0011] 1. A container containing liquefied gas, comprising a storage portion and liquefied gas stored in the storage portion, wherein the storage portion has a metal film on an inner surface, and a fluoride passivation film containing metal fluoride is provided on the metal film, the stored liquefied gas is composed of a liquid phase and a gas phase, and the liquid phase contains nickel element and / or copper element.

[0012] 2. The container containing liquefied gas according to 1., wherein the total content of the nickel element and the copper element in the liquid phase measured by ICP emission spectrometry is 10 wt ppb or more and 1000 wt ppm or less.

[0013] 3. The container containing liquefied gas according to 1. or 2., wherein the liquefied gas is HF or ClF 3 .

[0014] 4. The container containing liquefied gas according to any one of 1. to 3., wherein the amount of the main component in the gas phase of the liquefied gas is 99.9% by volume or more.

[0015] 5. The container containing liquefied gas according to any one of 1. to 4., wherein the F in the gas phase of the liquefied gas is 2 The amount is less than 100 volume ppm.

[0016] 6. The container containing liquefied gas according to any one of 1. to 5., wherein the storage portion comprises one or more selected from stainless steel, carbon steel, manganese steel, nickel steel, and aluminum steel.

[0017] 7. The container containing liquefied gas according to any one of 1. to 6., wherein the metal film has a plated film.

[0018] 8. The container containing liquefied gas according to any one of 1. to 7., wherein the metal film contains nickel and / or copper as a main component.

[0019] 9. The container containing liquefied gas according to any one of 1. to 8., wherein a film thickness of the metal film is 1 μm or more and 300 μm or less.

[0020] 10. The container containing liquefied gas according to any one of 1. to 9., wherein the fluoride passivation film is a room temperature fluoride passivation film.

[0021] 11. The container containing liquefied gas according to any one of 1. to 10., wherein at least a portion of the fluoride passivation film has dissolution marks.

[0022] 12. A method for manufacturing a container containing liquefied gas, the method comprising: a storage portion and liquefied gas stored in the storage portion, the method comprising the following steps: a step of forming a metal film on the inner surface of the storage portion; a step of forming a fluoride passivation film containing metal fluoride on the metal film; and a step of introducing the liquefied gas into the storage portion on which the fluoride passivation film is formed to obtain a container containing liquefied gas, the container containing liquefied gas having liquid and gas in the storage portion, the gas containing a gas phase of the liquefied gas, the liquid containing a liquid phase of the liquefied gas and further containing nickel element and / or copper element.

[0023] 13. The method for manufacturing a container containing liquefied gas according to 12., wherein the step of forming the fluoride passivation film is a step of causing a fluorine-containing gas to flow into the storage portion at room temperature and to contact the metal film.

[0024] Effects of the Invention

[0025] According to the present invention, a container containing liquefied gas and a method for manufacturing the container containing liquefied gas which are excellent in suppressing performance fluctuation of the liquefied gas can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 (a) is a cross-sectional view schematically showing an example of the structure of a container containing liquefied gas according to the present embodiment. Figure 1 (b) is an enlarged view of the α region of (a). DETAILED DESCRIPTION

[0027] Hereinafter, the embodiments of the present invention will be described using the accompanying drawings. In addition, in all the drawings, the same reference numerals are given to the same components and the description is omitted as appropriate. In addition, the drawings are schematic diagrams and are not consistent with the actual size ratios.

[0028] The outline of the container containing liquefied gas according to the present embodiment will be described.

[0029] The container containing liquefied gas according to the present embodiment includes a storage portion and liquefied gas stored in the storage portion.

[0030] The container filled with liquefied gas in this embodiment has the following structure: the storage portion has a metal film on the inner surface, and a fluoride passivation film containing metal fluoride is provided on the metal film. The storage portion contains gas and liquid, the gas contains a gas phase of liquefied gas, the liquid contains a liquid phase of liquefied gas, and also contains nickel element and / or copper element.

[0031] Furthermore, the above-mentioned “on the inner surface” and “on the metal film” may mean that the inner surface and the metal film are in direct contact, or that there is any film or layer interposed between the inner surface and the metal film.

[0032] The nickel and copper elements are contained in the liquid in the storage unit at a detection limit (1 ppb or more) when the content is measured by ICP emission spectrometry. The nickel and copper elements contained in the liquid may be contained in the form of metal or metal ions, or may be contained in part or in whole in the form of metal fluoride or metal fluoride ions (hereinafter, the metal state and the ion state are not distinguished, and are recorded as "metal" or "metal fluoride").

[0033] By using the container filled with liquefied gas of the present embodiment, it is possible to suppress the degradation of the highly corrosive liquefied gas and the accidental mixing of impurities. Therefore, the difference in gas composition between the initial liquefied gas before the container is opened and the liquefied gas after the gas starts to be released can be made extremely small, thereby suppressing changes in gas properties such as etching ability.

[0034] Usually, a container containing liquefied gas is directly installed in the gas supply section of various devices such as semiconductors, and the contents are taken out in the form of gas. However, when the gas properties change, it is necessary to adjust various settings of the gas supply object according to the changes. Furthermore, when the liquefied gas in the container is used up, a new container containing gas that has not been consumed is replaced. However, at this time, if there is a deviation in the gas properties before and after the replacement, it is necessary to readjust the various settings of the device to which the gas is supplied, which makes the operation complicated in the operation of mass production equipment.

[0035] According to the findings of the present inventors, it has been found that by coating the inner surface of a container containing liquefied gas with a metal film and a fluoride passivation film and containing a predetermined metal element in the non-gas (e.g., liquid) in the container, the above-mentioned change in gas performance can be suppressed.

[0036] Although the detailed mechanism is unclear, it is believed that the combined use of the metal film and the fluoride passivation film can further suppress the corrosion of the storage part by the liquefied gas compared to the case where they are used alone, thereby preventing impurities from the container from accidentally mixing into the liquid and gas in the container. Furthermore, it is believed that Ni, NiF dissolved in the liquid in the container 2 The fluorine mixed into the storage part is trapped by metals / metal fluorides, so that further changes in the gas composition of the gas can be suppressed. In addition, it is speculated that a trace amount of residual fluorine adsorbed on the surface of the film when the above-mentioned fluoride passivation film is formed is one of the sources of the above-mentioned fluorine. Therefore, it is believed that changes in the gas properties of the liquefied gas can be suppressed.

[0037] In addition, due to the Ni, NiF 2 Since the vapor pressure of metals and metal fluorides is relatively low, it is possible to suppress their mixing into the gas in the storage unit, thereby maintaining the purity of the liquefied gas taken out from the container containing the liquefied gas for a long time.

[0038] With regard to the content of nickel or copper in the liquid in the storage portion, the total content of the nickel and copper in the liquid is preferably 10 wt ppb or more and 1000 wt ppm or less, more preferably 30 wt ppb or more and 800 wt ppm or less, or 50 wt ppb or more and 500 wt ppm or less. In addition, in the case of containing only one of the nickel and copper elements, the content may be, for example, 10 wt ppb or more and 1000 wt ppm or less, preferably 30 wt ppb or more and 800 wt ppm or less, or more preferably 50 wt ppb or more and 500 wt ppm or less. By being within the above range, it is easy to suppress the change of the gas performance of the liquefied gas.

[0039] In addition, the liquid may contain other components as long as they do not affect the change of the gas properties of the gas phase of the liquefied gas. For example, components having a vapor pressure lower than that of the stored liquefied gas may be included, such as iron, cobalt, molybdenum, silver, etc.

[0040] The content of nickel or copper can be measured by ICP emission spectrometry. The measurement object is the liquefied gas just taken out from the container containing the liquefied gas (initial time).

[0041] The liquefied gas filled in the container containing the liquefied gas can be used for various purposes, and can be preferably used as a gas for semiconductors, for example.

[0042] Specifically, the liquefied gas may be a halogen-containing liquefied gas, preferably a fluorine-containing liquefied gas.

[0043] Among the fluorine-containing liquefied gases, HF and ClF 3 It can be preferably used as an etching gas for processing miniaturization in the semiconductor field.

[0044] Hereinafter, each structure of the container containing liquefied gas according to the present embodiment will be described in detail.

[0045] Figure 1 (a) is a cross-sectional view schematically showing the structure of a container 100 containing liquefied gas. Figure 1 (b) Figure 1 (a) Magnified view of the α region.

[0046] The container 100 containing liquefied gas includes a storage portion 10 filled with liquefied gas 30 .

[0047] The storage portion 10 contains a gas 35 and a liquid 33 . The gas 35 includes a gas phase 34 of the liquefied gas 30 . The liquid 33 includes a liquid phase 32 of the liquefied gas and further contains a nickel element and / or a copper element.

[0048] When the gas 35 substantially includes only the gas phase 34 as described later, it is preferable because a high-purity liquefied gas can be taken out from the container 100 containing the gas.

[0049] As long as it does not adversely affect the gas 35 and the gas phase 34 of the liquefied gas, the liquid 33 may contain any compound or component other than the liquid phase 32 of the liquefied gas and the nickel element and / or the copper element as described above. In addition, the liquid 33 may be substantially composed of only the liquid phase 32 and the nickel element and / or the copper element. For example, when all the liquids in the storage section 10 are taken as 100% by weight, the liquid phase 32 may be 98% by weight or more, and may preferably be 99% by weight or more, more preferably 99.5% by weight or more, and even more preferably 99.9% by weight or more.

[0050] When the internal space of the storage section 10 is taken as 100 volume %, the upper limit of the content of the liquid 33 may be, for example, 95 volume % or less, preferably 90 volume % or less, and more preferably 85 volume % or less. In addition, the content of the gas 35 in the storage section 10 may be, for example, 5 volume % or more, preferably 10 volume % or more, and more preferably 15 volume % or more. By making the volume of the gas 35 in the storage section 10 greater than or equal to a predetermined value, even if impurities are mixed into the gas 35, the larger the volume, the more the impurities are diluted, and the lower the concentration of the impurities, so that the influence on the gas performance can be suppressed.

[0051] On the other hand, the lower limit of the content of the liquid 35 may be, for example, 50% by volume or more in the initial stage out of 100% by volume of the internal space of the storage unit 10 , but is not limited thereto after the release of the liquefied gas 30 starts.

[0052] As the liquefied gas 30, there can be mentioned liquefied gases that are highly corrosive to metals, for example, HF and ClF 3 Since the stored liquefied gas 30 is easy to use when it is a single gas, the liquefied gas 30 is preferably HF or ClF. 3 Even the highly corrosive liquefied gas 30 can be stably stored in the container 100 containing the liquefied gas.

[0053] The gas 35 in the storage section 10 is preferably substantially composed of only the gas phase 34 of the liquefied gas 30. For example, 99.9% by volume or more of the gas 35 in the storage section 10 may be the gas phase 34 of the liquefied gas 30. More preferably, 99.95% by volume or more, and further preferably 99.99% by volume or more may be the gas phase 34 of the liquefied gas 30. Thus, the liquefied gas 30 can be used while maintaining a high purity.

[0054] It is preferred that the gas 35 in the storage unit 10 contain as little F as possible. 2, for example, it can be less than 100 volume ppm, preferably less than 30 volume ppm, and more preferably less than 10 volume ppm. Thus, the liquefied gas 30 can be used while maintaining high purity.

[0055] In this specification, ICP emission spectrometry can be used to measure the types and amounts of components in the gas 35 in the container. The measurement target is the gas 35 just taken out from the container 100 containing the liquefied gas (at the initial stage).

[0056] The storage portion 10 is constituted by a container having an internal space surrounded by a wall portion.

[0057] The storage portion 10 may be made of a corrosion-resistant metal material or a ceramic material.

[0058] The storage section 10 can be composed of one or more of stainless steel, carbon steel, manganese steel, nickel steel, and aluminum steel. In addition, nickel alloys such as monel and hastelloy, and materials made of the above-mentioned various steels through polishing, etc. can be used. Among them, from the viewpoint of low price and excellent durability, stainless steel (SUS) and manganese steel are preferred. As long as the above-mentioned stainless steel is used as a known container, it can be, for example, an alloy steel of iron of more than 50 mass % and any component (chromium, nickel, etc.) for improving corrosion resistance.

[0059] In addition, the storage portion 10 may contain inevitably mixed metal elements such as nickel and chromium in addition to the corrosion-resistant metal material as a main component.

[0060] The housing portion 10 includes a metal film 20 formed on the inner surface 12 , and a fluoride passivation film 22 including metal fluoride formed on the metal film 20 .

[0061] The metal film 20 and the fluoride passivation film 22 are configured to cover at least the inner surface 12 where the liquid 33 exists, and may also cover the entire surface of the inner surface 12. In addition, when the metal film 20 does not cover the entire surface of the inner surface 12, the non-coated surface of the metal film 20 is ideally a surface or film that is not easily corroded by the liquefied gas 30 and does not have an adverse effect on the gas phase 34 even if corroded. The surface and film as described above can be used with known surfaces and films, and are not particularly limited. As the film, for example, a gold-plated film, a fluororesin film, etc. can be cited.

[0062] The metal film 20 may be configured to include nickel and / or copper as main components. In addition to nickel and copper, any component constituting the metal film 20 may also be included. As the arbitrary component, it is ideal to be a component that is not easy to react with the liquefied gas 30, and examples thereof include gold, fluororesin, etc. In addition, even if a component can be partially mixed from the metal film 20 into the liquid 33, as long as the vapor pressure is low as described above and it does not have an adverse effect on the gas phase 34, it may be included in the metal film 20. For example, iron element, cobalt element, molybdenum element, silver element, etc. may be mentioned. In addition, of course, even if gold element, fluororesin, etc. are not constituent components of the metal film 20, they may be included in the metal film 20.

[0063] Furthermore, in order to improve the adhesion between the metal film 20 and the inner surface 12 , the durability of the metal film 20 , and the like, an arbitrary coating layer may be provided between the metal film 20 and the inner surface 12 .

[0064] In this specification, the main component means 80% by weight or more in terms of weight.

[0065] When the metal film contains both nickel and copper, “containing nickel and copper as main components” means that the total content of the both in the metal film is 80% by weight or more.

[0066] The film thickness of the metal film 20 is, for example, not less than 1 μm and not more than 300 μm, preferably not less than 2 μm and not more than 200 μm, and more preferably not less than 3 μm and not more than 100 μm.

[0067] The method for forming the metal film 20 is not limited, and for example, it can be formed by a sputtering film or a plated film. In particular, from the perspective of being easy to form a film along the shape of the container, a plated film is preferred. In addition, when a plated film is used, the inner surface of the storage portion 10 constituting the container and the outer surface of the container can be made of different materials, and a desired container can be obtained at low cost, which is preferred. The plated film can be formed by a known method, and examples thereof include electroplating, chemical plating, hot dip plating, and the like.

[0068] The storage unit 10 has an inlet and outlet mechanism for introducing the liquefied gas 30 into the interior of the space and / or releasing the gas 35 in the storage unit 10 to the outside. As an example of the inlet and outlet mechanism, the storage unit 10 has a Figure 1 The outlet 50 shown in the figure and the filling port for liquefied gas (for example, having a liquid contact member for filling) not shown in the figure. The outlet 50 may be provided with a valve 40. In addition, the outlet 50 and the filling port may be the same.

[0069] The valve 40, the outlet 50, and the filling port may be made of corrosion-resistant metal materials or ceramic materials, or may be made of the same material as the storage portion 10. In addition, the surfaces of the valve 40, the outlet 50, and the filling port that are in contact with the liquefied gas 30 and the gas 35 in the storage portion may be formed with the above-mentioned metal film 20 and fluoride passivation film 22.

[0070] The material of the outer surface of the container 100 containing liquefied gas, that is, the outer surface of the wall portion in contact with the external atmosphere, is not particularly limited, and can be a corrosion-resistant metal material or a ceramic material as in the storage portion 10. In addition, in order to improve physical strength and chemical strength, any coating can be applied to the surface. In addition, the outer surface can be made of the same material as the metal film 20, but from the viewpoint of low price and excellent durability, stainless steel (SUS) and manganese steel are preferred.

[0071] The fluoride passivation film 22 includes the metal component contained in the metal film 20 and F 2 Depending on the metal component contained in the metal film 20, the metal fluoride can be NiF 2 ,CuF 2 wait.

[0072] Furthermore, when the storage portion 10 is not covered with the fluoride passivation film 22 and only the metal film 20 is formed, the metal film 20 and the liquefied gas 30 may react and impurities may be mixed into the gas 35 in the storage portion 10 .

[0073] The fluoride passivation film 22 may have dissolution marks at least partially.

[0074] The above-mentioned dissolution mark can be generated at the gas-liquid interface between the liquid phase 32 and the gas phase 34 of the liquefied gas 30. In addition, the above-mentioned gas-liquid interface can also be a gas-liquid interface between the liquid 33 and the gas 35 in the storage part 10. The durability of the fluoride passivation film 22 can also be managed according to the depth of the dissolution mark. The dissolution mark can refer to a portion where the above-mentioned gas-liquid interface contacts the metal film and the fluoride passivation film of the storage part 10, and a discoloration can be visually confirmed, or a portion where unevenness or peeling of the coating is generated.

[0075] The container 100 containing the liquefied gas can be stored, transported, etc., for example, at a temperature of 40° C. or less, preferably 30° C. or less, and more preferably 25° C. or less. In addition, the temperature of the container 100 containing the liquefied gas during operation can be, for example, 40° C. or less, preferably 30° C. or less, and more preferably 25° C. or less.

[0076] The container of the present invention suppresses performance fluctuations more than conventional containers at high temperatures during storage and transportation. This is also effective in summer. From this point of view, as one embodiment of the present invention, the container of the present invention containing liquefied gas is stored at 30 to 40°C.

[0077] That is, one form of the liquefied gas storage method of the present embodiment may include the following steps: a step of introducing the liquefied gas 30 into the storage portion 10 of the above-mentioned liquefied gas container 100; and a step of storing the liquefied gas container 100 filled with the liquefied gas 30 under a specified temperature environment.

[0078] In the method for storing liquefied gas, the liquefied gas 30 may be a halogen-containing liquefied gas or a fluorine-containing liquefied gas.

[0079] In the method for storing liquefied gas, the temperature environment in the storage step is, for example, preferably 25° C. or higher and 40° C. or lower, and more preferably 30° C. or higher and 40° C. or lower.

[0080] An example of a method for manufacturing a container 100 containing liquefied gas includes the following steps: a step of forming a metal film 20 on the inner surface 12 of a storage portion 10; a step of forming a fluoride passivation film 22 containing metal fluoride on the metal film 20; and a step of introducing liquefied gas 30 into the storage portion 10 on which the fluoride passivation film 22 is formed to obtain the container 100 containing liquefied gas, wherein the container 100 containing liquefied gas has a liquid 33 and a gas 35 in the storage portion 10, the gas 35 containing a gas phase 34 of the liquefied gas 30, the liquid 33 containing a liquid phase 32 of the liquefied gas 30, and further containing nickel elements and / or copper elements.

[0081] The metal film 20 may be formed by a known method, such as electroplating, chemical plating, hot dip plating, etc. The plating solution for the metal plating process may be appropriately selected according to the process and the metal film 20 to be formed, and is not particularly limited.

[0082] In the step of forming the fluoride passivation film 22 containing metal fluoride, the metal component contained in the metal film 20 can be reacted with the fluorine-containing gas as described above to obtain the fluoride passivation film 22 containing metal fluoride. The fluorine-containing gas can be, for example, F 2 In the case of reacting with a fluorine-containing gas, the contact may be carried out at, for example, 100° C. or lower.

[0083] In addition, when the fluoride passivation film 22 is a room temperature fluoride passivation film, the room temperature fluoride passivation film can be produced by allowing a fluorine-containing gas to flow at room temperature into the container 100 filled with liquefied gas after the metal film 20 is formed on the inner surface, and to contact the above-mentioned metal film 20.

[0084] The above-mentioned "normal temperature" is not particularly limited as long as the temperature of the fluorine-containing gas is maintained at a level where the reaction between the fluorine-containing gas and the metal film 20 does not become violent or significantly slow. It can be, for example, in the range of 5 to 35°C, more preferably 10 to 35°C, and further preferably 10 to 30°C. In addition, when the working environment is excessively high or low temperature, it can be heated or cooled to be within the above-mentioned normal temperature range.

[0085] In addition, during the introduction of the liquefied gas 30, the liquefied gas 30 in liquid form is introduced into the storage portion 10. In addition, when the interior of the container 100 containing the liquefied gas is replaced with an inert gas before the liquefied gas 30 is introduced, it is preferred that the gas other than the liquefied gas represented by the remaining fluorine-containing gas can be efficiently removed.

[0086] When the liquefied gas 30 is introduced after the fluoride passivation film 22 is formed, a liquid 33 and a gas 35 containing the liquefied gas 30 are formed in the storage portion 10, and nickel and / or copper are supplied to the liquid 33. Although the detailed mechanism is unclear, it is presumed that the remaining metal elements from the metal film 20 attached to the fluoride passivation film 22 are introduced into the liquid 33, or a part of the fluoride passivation film 22 is dissolved into the liquid 33 by the introduction of the liquefied gas 30. For example, when the liquid 33 in the storage portion 10 is substantially only HF or ClF 3 When the liquid phase 32 of the liquefied gas is introduced, the metal film 20 and the fluoride passivation film 22 of the preferred embodiment of the present invention are not easily dissolved in the liquid phase 32, and the corrosion cycle of the inner wall of the container can be difficult to proceed. However, on the other hand, it is inferred that a trace amount of dissolution may occur, and therefore, a trace amount of dissolution occurs while the liquefied gas 30 is introduced, and the nickel element and / or the copper element are supplied to the liquid 33.

[0087] In addition, as a method for supplying the nickel element and / or copper element contained in the above-mentioned liquid 33, a supply source of the nickel element or the copper element may be pre-configured in the liquid-contacting component or the storage portion 10 for filling the liquefied gas 30, and then the liquefied gas 30 may be introduced and supplied to the liquid 33 from the supply source.

[0088] The embodiments of the present invention are described above, but these are examples of the present invention, and various configurations other than the above can be adopted. In addition, the present invention is not limited to the above embodiments, and modifications and improvements within the scope of achieving the purpose of the present invention are included in the present invention.

[0089] Example

[0090] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited at all to the descriptions of these Examples.

[0091] <Manufacturing of Containers Containing Liquefied Gas>

[0092] (Example 1)

[0093] Follow these steps to make Figure 1 A container 100 containing liquefied gas is shown.

[0094] First, a stainless steel container (storage portion 10 ) having an internal space for storing liquefied gas, a valve, and a take-out port is prepared.

[0095] Next, the entire inner wall of the container is plated with nickel (Ni concentration relative to the entire plating solution = 15 wt %) to form a 50 μm thick nickel plated film (metal film 20 ) on the inner wall (inner surface 12 ) (plating treatment).

[0096] Next, at room temperature, 2 The gas (99.9% by volume purity, fluorine-containing gas) comes into contact with the nickel plated film, forming a NiF 2 A passivation film (fluoride passivation film 22 containing metal fluoride) (fluorine gas treatment) is formed.

[0097] Afterwards, remove F from the interior of the container 2 The gas is replaced with He gas (inert gas) (replacement treatment).

[0098] After the replacement, HF in a gaseous state (liquefied gas) is introduced into the inner space of the container, and HF in a liquid state is filled (liquefied gas filling process).

[0099] Through the above steps, a container containing liquefied gas was produced, in which the liquid phase of the liquefied gas accounted for 80 volume % in the internal space of the container.

[0100] (Example 2)

[0101] A container containing liquefied gas was prepared in the same manner as in Example 1, except that the Ni concentration in the plating solution used for nickel plating was higher than that in Example 1.

[0102] (Example 3)

[0103] A container containing liquefied gas was produced in the same manner as in Example 1 except that the material of the container was changed from stainless steel to manganese steel.

[0104] (Example 4)

[0105] A container containing liquefied gas was produced in the same manner as in Example 1 except that the metal plating was changed from nickel plating to copper plating.

[0106] (Example 5)

[0107] A container containing liquefied gas was prepared in the same manner as in Example 4, except that the Cu concentration in the plating solution used for copper plating was set higher than that in Example 4.

[0108] (Example 6)

[0109] Changed the type of liquefied gas from HF to ClF 3 , except for this, the same procedure as in Example 1 was followed to prepare a container containing liquefied gas.

[0110] (Example 7)

[0111] Changed the type of liquefied gas from HF to ClF 3 , except for this, the same procedure as in Example 2 was followed to prepare a container containing liquefied gas.

[0112] (Example 8)

[0113] Changed the type of liquefied gas from HF to ClF 3 , except for this, the same procedure as in Example 4 was followed to prepare a container containing liquefied gas.

[0114] (Example 9)

[0115] Changed the type of liquefied gas from HF to ClF 3 , except for this, the same procedure as in Example 5 was followed to prepare a container containing liquefied gas.

[0116] It was confirmed that in Examples 1 to 9, the liquefied gas (HF or ClF 3 ) is a state consisting of two phases: liquid and gas.

[0117] Furthermore, it was confirmed that in Examples 1 to 3 and 6 to 7, a layer containing NiF was formed on the nickel plating film. 2 In Examples 4 to 5 and 8 to 9, a passivation film including CuF is formed on the copper plating film. 2 Passivation film.

[0118] (Comparative Example 1)

[0119] A container containing liquefied gas was prepared in the same manner as in Example 1 except that the fluorine gas treatment was performed instead of the plating treatment.

[0120] (Comparative Example 2)

[0121] A container containing liquefied gas was prepared in the same manner as in Example 6, except that the fluorine gas treatment was performed instead of the plating treatment.

[0122] [Table 1]

[0123]

[0124] The liquefied gas containers of each Example and each Comparative Example were evaluated based on the following evaluation items.

[0125] (Metal concentration in liquid)

[0126] The metal concentrations (wt.ppm) of nickel and copper contained in the liquid in the container were measured by ICP emission spectrometry. In addition, regarding the metal concentrations, the values ​​when the container was initially filled with liquefied gas, when the valve of the container was opened and the gas containing liquefied gas was slowly released from the outlet so that the remaining amount of liquid in the container was 80% relative to the initial amount in terms of volume, and when the remaining amount of liquid in the container was 20% are shown in Table 1.

[0127] In addition, the "Metal Type" of "Metal Concentration in Liquid" in Table 1 records nickel or copper, and in the examples where only one element is recorded, such as Examples 1 to 9, the unrecorded element is less than 1 ppb (less than the detection limit). In addition, in Comparative Examples 1 and 2, the concentrations of nickel and copper elements are less than 1 ppb (less than the detection limit) at the initial stage, when the remainder is 80%, and when the remainder is 20%, and nickel and copper elements are not confirmed in the liquid.

[0128] (F in gas 2 concentration)

[0129] The F content of the gas in the container was determined by ICP emission spectrometry. 2 Concentration (wt. Vol). In addition, regarding F 2 The concentration is measured by taking the gas (gas) just released from the outlet as the object of measurement. The values ​​are shown in Table 1 when the container is initially filled with liquefied gas, when the valve of the container is opened and the gas containing liquefied gas is slowly released from the outlet so that the remaining amount of liquid in the container is 80% by volume relative to the initial period, and when the remaining amount of liquid in the container is 20%.

[0130] In Examples 1 to 9, the ICP emission spectrometry was used to measure the initial HF concentration or ClF 3 Concentration. It was confirmed in all the examples that the initial concentration of HF or ClF in the gas 3 The concentrations were all above 99.9% by volume.

[0131] (Etching speed)

[0132] First, the structure of the etching device is described. The reaction chamber has a carrier for supporting a sample. The sample used is a sample in which a silicon oxide film (20nm) is formed on a 6-inch silicon substrate, and a polysilicon film (30μm) is formed thereon. The carrier has a carrier temperature regulator capable of adjusting the temperature of the carrier. The reaction chamber is connected to a first gas pipe for introducing gas and a second gas pipe for exhausting gas. The etching gas supply system is connected to the first gas pipe via a first valve to supply the above-mentioned substrate processing gas to the reaction chamber. The vacuum pump is connected to the second gas pipe via a second valve to exhaust the gas.

[0133] The pressure inside the reaction chamber is controlled using a second valve based on the indication value of a pressure gauge attached to the reaction chamber.

[0134] Next, the operation method of the etching device is described. The sample is placed on the stage, and after the reaction chamber and the first gas pipe and the second gas pipe are vacuum replaced until 1.5 kPa, the temperature of the stage is set to the specified value (25°C). After confirming that the temperature of the stage has reached the specified value, open the first valve and the second valve, set the pressure of the etching gas supply system to the specified pressure (100 Pa), and introduce the liquefied gas stored in the container containing the liquefied gas into the reaction chamber through the first gas pipe as the substrate processing gas. The total flow rate of the substrate processing gas at this time is 100 sccm.

[0135] After a predetermined time (etching time, 1 minute) has passed since the substrate processing gas was introduced, the introduction of the substrate processing gas was stopped, the interior of the reaction chamber was replaced with a vacuum, and then the sample was taken out to measure the etching rate.

[0136] Using the silicon substrate (sample) with a polysilicon film, the film thickness of the polysilicon film before etching and the film thickness of the polysilicon film after etching were measured at 5 locations, and the etching amount (the difference in film thickness before etching and after etching) of each measured location was obtained. The etching rate (nm / min) was calculated based on the average of the etching amount of each measured location and the etching time.

[0137] Regarding the etching rate, when the initial value when the container is just filled with liquefied gas is set to 1.0, the valve of the container is opened and the gas is slowly released from the outlet so that the remaining amount of liquid in the container is 80% by volume relative to the initial period, and the relative value when the remaining amount of liquid in the container is 20% is shown in Table 1.

[0138] As described above, nickel or copper was confirmed in the liquid in the container containing liquefied gas in Examples 1 to 9, indicating that the composition of the gas in the container can be basically fixed from the beginning of opening to the end of use. In addition, the etching rate of the gas in all examples is basically fixed, which shows that the performance change of the liquefied gas can be suppressed compared with Comparative Examples 1 and 2.

[0139] Furthermore, the liquefied gas filled in the container containing the liquefied gas in each embodiment can be preferably used for semiconductor applications such as etching gas.

[0140] This application claims priority based on Japanese patent application No. 2022-199993 filed on December 15, 2022, and all of its disclosed contents are incorporated herein.

[0141] Description of Reference Numerals

[0142] 10: Storage department;

[0143] 12: inner surface;

[0144] 20: Metal film;

[0145] 22: Fluoride passivation film;

[0146] 30: Liquefied gas;

[0147] 32: liquid phase;

[0148] 33: liquid;

[0149] 34: gas phase;

[0150] 35: Gas;

[0151] 40: valve;

[0152] 50: Take the exit;

[0153] 100: Containers containing liquefied gas.

Claims

1. A container filled with liquefied gas, which has a storage part and liquefied gas stored in the storage part. The inner surface of the storage part has a metal film, and a fluoride passivation film containing metal fluoride is provided on the metal film. The storage part contains liquid and gas. The gas contains the gas phase of the liquefied gas. The liquid contains the liquid phase of the liquefied gas and also contains nickel element and / or copper element.

2. The container filled with liquefied gas according to claim 1. Wherein, The total content of the nickel element and copper element in the liquid measured by ICP emission spectrometry is 10 weight ppb or more and 1000 weight ppm or less.

3. The container filled with liquefied gas according to claim 1 or 2. Wherein, The liquefied gas is HF or ClF 3 .

4. The container filled with liquefied gas according to claim 1 or 2. Wherein, 99.9 volume % or more of the gas is the gas phase of the liquefied gas.

5. The container filled with liquefied gas according to claim 1 or 2. Wherein, The amount of F in the gas 2 is less than 100 volume ppm.

6. The container filled with liquefied gas according to claim 1 or 2. Wherein, The storage part includes one or more selected from stainless steel, carbon steel, manganese steel, nickel steel, and aluminum steel.

7. The container filled with liquefied gas according to claim 1 or 2. Wherein, The metal film has a coating film.

8. The container filled with liquefied gas according to claim 1 or 2. Wherein, The metal film contains nickel and / or copper as the main component.

9. The container filled with liquefied gas according to claim 1 or 2. Wherein, The film thickness of the metal film is 1 μm or more and 300 μm or less.

10. The container filled with liquefied gas according to claim 1 or 2. Wherein, The fluoride passivation film is a room temperature fluoride passivation film.

11. The container filled with liquefied gas according to claim 1 or 2. Wherein, At least a part of the fluoride passivation film has dissolution marks.

12. A manufacturing method of a container filled with liquefied gas, which is a manufacturing method of a container filled with liquefied gas having a storage part and liquefied gas stored in the storage part. The manufacturing method has the following steps: A step of forming a metal film on the inner surface of the storage part; A step of forming a fluoride passivation film containing metal fluoride on the metal film; and A step of introducing the liquefied gas into the storage part formed with the fluoride passivation film to obtain a container filled with liquefied gas. The container filled with liquefied gas has liquid and gas in the storage part. The gas contains the gas phase of the liquefied gas. The liquid contains the liquid phase of the liquefied gas and also contains nickel element and / or copper element.

13. The manufacturing method of the container filled with liquefied gas according to claim 12. Wherein, The step of forming the fluoride passivation film is a step of flowing a fluorine-containing gas into the storage part at room temperature and bringing it into contact with the metal film.

Images