WO2024247730A1 - Method for storing phosphorus fluoride, storage container, and gas-loaded storage container - Google Patents
Method for storing phosphorus fluoride, storage container, and gas-loaded storage container Download PDFInfo
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- WO2024247730A1 WO2024247730A1 PCT/JP2024/018017 JP2024018017W WO2024247730A1 WO 2024247730 A1 WO2024247730 A1 WO 2024247730A1 JP 2024018017 W JP2024018017 W JP 2024018017W WO 2024247730 A1 WO2024247730 A1 WO 2024247730A1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/3065—Plasma etching; Reactive-ion etching
Definitions
- the present invention relates to a method for storing phosphorus fluoride, which is at least one of phosphorus trifluoride (PF 3 ), phosphorus pentafluoride (PF 5 ), and diphosphorus tetrafluoride (P 2 F 4 ), a storage container, and a gas-filled storage container.
- phosphorus fluoride which is at least one of phosphorus trifluoride (PF 3 ), phosphorus pentafluoride (PF 5 ), and diphosphorus tetrafluoride (P 2 F 4 )
- PF 3 phosphorus trifluoride
- PF 5 phosphorus pentafluoride
- P 2 F 4 diphosphorus tetrafluoride
- Phosphorus fluorides such as phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, and fluorine-containing gases such as chlorine trifluoride (ClF 3 ) and iodine heptafluoride (IF 7 ) are used as dry etching gases for semiconductor manufacturing.
- the dry etching gas is required to have a high purity (for example, 99.9% by volume or more).
- the dry etching gas is stored in a filled state in a storage container, it is necessary to maintain the high purity in the storage container for a long period of time.
- metal impurities that may cause particle generation during dry etching must be suppressed to a concentration of 1 mass ppm or less.
- Patent Document 1 discloses a technology in which the inner surface of a storage container that stores fluorine-containing gas is fluorinated to suppress reaction between the fluorine-containing gas and the metal material that forms the storage container.
- the storage container is filled with fluorine-containing gas after a fluorination treatment that causes a reaction between the metal material that forms the inner surface of the storage container and the fluorine-containing gas has been carried out in advance, so that reaction between the metal material that forms the storage container and the filled fluorine-containing gas is unlikely to occur, and the generation of metal impurities is suppressed.
- a decrease in the purity of the filled fluorine-containing gas is suppressed for a long period of time.
- An object of the present invention is to provide a method for storing phosphorus fluoride, a storage container, and a gas-filled storage container in which an increase in the concentration of metal impurities is unlikely to occur.
- a method for storing phosphorus fluoride which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, comprising: storing the phosphorus fluoride in a storage container having a portion that comes into contact with the phosphorus fluoride made of a metal material; A method for storing phosphorus fluoride, wherein the total concentration of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass % or less.
- [2] The method for storing phosphorus fluoride according to [1], wherein the metal material is at least one of manganese steel and chromium molybdenum steel.
- [3] The method for storing phosphorus fluoride according to [1] or [2], wherein the concentrations of copper, magnesium, calcium, and palladium contained in the metal material are measured by X-ray photoelectron spectroscopy.
- [4] The method for storing phosphorus fluoride according to any one of [1] to [3], wherein the phosphorus fluoride is stored in the storage container with a purity of 99.90% by volume or more.
- a storage container for storing phosphorus fluoride which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride
- the metal material is at least one of manganese steel and chromium molybdenum steel.
- the concentration of metal impurities in the phosphorus fluoride is unlikely to increase.
- the method for storing phosphorus fluoride is a method for storing phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, in which the phosphorus fluoride is stored in a storage container in which the portion that the phosphorus fluoride comes into contact with is made of a metal material.
- the sum of the concentrations of copper, magnesium, calcium, and palladium contained in this metal material is 0.8 mass% or less.
- the phosphorus fluoride storage container is a storage container for storing phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, and is a container in which the portion that comes into contact with the phosphorus fluoride is formed of a metal material.
- the sum of the concentrations of copper, magnesium, calcium, and palladium contained in this metal material is 0.8 mass% or less.
- the gas-filled storage container according to this embodiment is a gas-filled storage container in which phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, is filled in the storage container, the portion of the storage container that comes into contact with the phosphorus fluoride is formed of a metal material, and the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass% or less.
- phosphorus fluoride which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride
- the metal material forming the part of the storage container that comes into contact with phosphorus fluoride contains at least one of copper, magnesium, calcium, and palladium, the catalytic action of these metals promotes a reaction in which metal atoms contained in the metal material and phosphorus fluoride form a complex. Therefore, if phosphorus fluoride is stored in a storage container formed of a metal material containing at least one of copper, magnesium, calcium, and palladium, the above complex formation reaction may progress during storage in the storage container, resulting in the generation of metal impurities and a decrease in the purity of the phosphorus fluoride.
- the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material forming the portion of the storage container that comes into contact with the phosphorus fluoride is 0.8 mass% or less, so the above complex formation reaction is unlikely to proceed even during long-term storage.
- metal impurities are unlikely to be generated, and therefore the concentration of metal impurities is unlikely to increase (i.e., the purity of the phosphorus fluoride is unlikely to decrease). Therefore, the phosphorus fluoride can be stored stably for long periods of time.
- Metals that form complexes with phosphorus fluoride include, for example, nickel (Ni), zinc (Zn), chromium (Cr), molybdenum (Mo), and tungsten (W).
- Ni nickel
- Zn zinc
- Cr chromium
- Mo molybdenum
- W tungsten
- the sum of the concentrations of nickel, zinc, chromium, molybdenum, and tungsten in phosphorus fluoride is preferably maintained at 1000 mass ppb or less, more preferably at 800 mass ppb or less, and even more preferably at 500 mass ppb or less. If the sum of the concentrations of nickel, zinc, chromium, molybdenum, and tungsten in phosphorus fluoride is 1000 mass ppb or less, it tends to avoid poor etching performance when phosphorus fluoride is used as a dry etching gas.
- the phosphorus fluoride storage method, storage container, and gas-filled storage container according to this embodiment are such that the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material forming the portion of the storage container that stores phosphorus fluoride and that comes into contact with the phosphorus fluoride is 0.8 mass% or less.
- the metal material may contain at least one of copper, magnesium, calcium, and palladium (i.e., the sum of the concentrations may be more than 0 mass% and 0.8 mass% or less), or may not contain any of these elements at all (i.e., the sum of the concentrations may be 0 mass%).
- the phosphorus fluoride is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride. That is, the phosphorus fluoride may be any one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, or may be a mixture of two or three of them.
- the content of the main component which is the component with the greatest content, is preferably 99 mol% or more, more preferably 99.9 mol% or more, and even more preferably 99.99 mol% or more.
- the total content of components other than the main component is preferably 0.1 mol% or less, more preferably 0.01 mol% or less, and even more preferably 0.001 mol% or less.
- a gas consisting of phosphorus fluoride alone may be stored in the storage container, or a mixed gas containing phosphorus fluoride and a diluent gas may be stored in the storage container. Also, a part or all of phosphorus fluoride may be liquefied and stored in the storage container.
- the diluent gas at least one selected from nitrogen gas (N 2 ), helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe) may be used.
- the content of the diluent gas is preferably 90% by volume or less, more preferably 50% by volume or less, of the total amount of gas stored in the storage container.
- the phosphorus fluoride storage method, storage container, and gas-filled storage container it is preferable to store phosphorus fluoride with a purity of 99.90% by volume or more in the storage container. If the purity of the phosphorus fluoride introduced into the storage container is 99.90% by volume or more, the effect of being able to etch the object to be etched selectively and at a sufficient etching rate compared to the object not to be etched is achieved.
- the shape, size, etc. of the storage container for storing or filling phosphorus fluoride are not particularly limited as long as the storage container can contain and seal phosphorus fluoride, the portion that contacts phosphorus fluoride is formed of a metal material, and the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass% or less.
- the material of the portion of the storage container that does not contact phosphorus fluoride is not particularly limited. However, it is preferable that the storage container has corrosion resistance against phosphorus fluoride.
- the metal material examples include manganese steel, stainless steel, chromium molybdenum steel, Hastelloy (registered trademark), Inconel (registered trademark), Monel (registered trademark), etc., from the viewpoint of corrosion resistance.
- the metal material may be at least one of manganese steel and chromium molybdenum steel.
- Storage containers made of manganese steel and chrome-molybdenum steel include, for example, containers manufactured from steel pipes specified in the JIS standard JIS G3429 (seamless steel pipes for high-pressure gas containers) STH11, STH12 (manganese steel pipes) and STH21, STH22 (chrome-molybdenum steel pipes).
- the storage container also includes a valve, and like the storage container, the valve is preferably made of manganese steel, stainless steel, or chrome molybdenum steel. Valves made of brass or copper alloys such as Monel (registered trademark) can also be used as long as they are designed not to come into direct contact with phosphorus fluoride.
- the metal material in the storage method, storage container, and gas-filled storage container of phosphorus fluoride according to this embodiment contains or does not contain at least one of copper, magnesium, calcium, and palladium, but when it contains, the sum of the concentrations of copper, magnesium, calcium, and palladium is 0.8 mass% or less, so that the complex formation reaction between phosphorus fluoride and nickel, zinc, chromium, molybdenum, and tungsten does not proceed easily as described above.
- the absence of the above means that it is not possible to quantitatively determine the concentration by X-ray photoelectron spectroscopy (XPS analysis). That is, the concentrations of copper, magnesium, calcium, and palladium contained in the metal material can be measured by X-ray photoelectron spectroscopy. More specifically, they can be measured by the method described in the examples.
- the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material must be 0.8 mass% or less, preferably 0.4 mass% or less, and more preferably 0.2 mass% or less.
- copper, magnesium, calcium, and palladium are thought to be contaminated into the storage containers due to the metal materials that are the raw materials of the storage containers, or due to the manufacturing equipment for the storage containers that is used in manufacturing the storage containers.
- the phosphorus fluoride (phosphorus fluoride before filling) filled into the storage container contains low concentrations of copper, magnesium, calcium, and palladium.
- An example of a method for producing phosphorus fluoride with low concentrations of copper, magnesium, calcium, and palladium is a method for removing copper, magnesium, calcium, and palladium from phosphorus fluoride having a high sum of copper, magnesium, calcium, and palladium concentrations.
- the method for removing copper, magnesium, calcium, and palladium from phosphorus fluoride includes a method using a filter, a method using an adsorbent, distillation, etc.
- the material of the filter that selectively passes the phosphorus fluoride gas is preferably a resin, and polytetrafluoroethylene is particularly preferred, in order to prevent metal components from being mixed into the phosphorus fluoride.
- the average pore size of the filter is preferably 0.01 ⁇ m or more and 30 ⁇ m or less, and more preferably 0.1 ⁇ m or more and 10 ⁇ m or less. If the average pore size is within the above range, it is possible to sufficiently remove copper, magnesium, calcium, and palladium, and a sufficient flow rate of the phosphorus fluoride gas can be secured, thereby achieving high productivity.
- the flow rate of the fluorinated gas passing through the filter is preferably 3 mL/min to 300 mL/min, more preferably 10 mL/min to 50 mL/min per cm2 of filter area. If the flow rate of the fluorinated gas is within the above range, the fluorinated gas is prevented from becoming high pressure, the risk of leakage of the fluorinated gas is reduced, and high productivity can be achieved.
- concentrations of copper, magnesium, calcium, and palladium contained in the fluorinated phosphorus can be quantified by an inductively coupled plasma mass spectrometer (ICP-MS).
- the pressure conditions during storage in the method for storing phosphorus fluoride according to this embodiment and the gas-filled storage container according to this embodiment are not particularly limited as long as phosphorus fluoride can be stored hermetically in the storage container, but are preferably 0.15 MPa or more and 15 MPa or less, and more preferably 0.3 MPa or more and 9 MPa or less. If the pressure conditions are within the above range, phosphorus fluoride can be circulated without heating when the storage container is connected to a dry etching device.
- the temperature conditions during storage in the method for storing phosphorus fluoride according to this embodiment and the gas-filled storage container according to this embodiment are not particularly limited, but are preferably -20°C or higher and 50°C or lower, and more preferably 0°C or higher and 40°C or lower. If the storage temperature is -20°C or higher, the storage container is unlikely to deform, so there is a low possibility that the airtightness of the storage container will be lost and oxygen, water, etc. will be mixed into the storage container. If oxygen, water, etc. are mixed in, the decomposition reaction of phosphorus fluoride may be promoted. On the other hand, if the storage temperature is 50°C or lower, the complex formation reaction between phosphorus fluoride and nickel, zinc, chromium, molybdenum, and tungsten will not proceed easily.
- the phosphorus fluoride stored in the storage method, storage container, and gas-filled storage container according to the present embodiment can be used as an etching gas.
- the phosphorus fluoride-containing etching gas stored in the storage method, storage container, and gas-filled storage container according to the present embodiment can be used in both plasma etching using plasma and plasmaless etching not using plasma.
- plasma etching examples include reactive ion etching (RIE), inductively coupled plasma (ICP) etching, capacitively coupled plasma (CCP) etching, electron cyclotron resonance (ECR) plasma etching, and microwave plasma etching.
- RIE reactive ion etching
- ICP inductively coupled plasma
- CCP capacitively coupled plasma
- ECR electron cyclotron resonance
- microwave plasma etching the plasma may be generated in a chamber in which the member to be etched is placed, or the plasma generation chamber may be separate from the chamber in which the member to be etched is placed (i.e., remote plasma may be used).
- Example 1 A seamless container with a volume of 10 L made of manganese steel was prepared, and its inner surface was shot blasted, acid washed, and washed with water in the order described, and then dried. A valve was attached to the dried container to prepare a storage container.
- the valve was made of SUS316L, which has a total concentration of copper, magnesium, calcium, and palladium of less than 0.005 mass%.
- the storage container was heated to 160°C, and the inside of the storage container was depressurized using a vacuum pump to create a vacuum.
- the storage container with the inside in a vacuum state was then connected to a gas filling line equipped with a cylinder filled with phosphorus trifluoride.
- the cylinder filled with phosphorus trifluoride was made of SUS316, with the total concentration of copper, magnesium, calcium, and palladium being less than 0.005% by mass.
- the phosphorus trifluoride filled in the cylinder was analyzed by gas chromatography, its purity was found to be 99.95% by volume. Furthermore, when the phosphorus trifluoride filled in the cylinder was analyzed by inductively coupled plasma mass spectrometry, the total concentration of copper, magnesium, calcium, and palladium contained in the phosphorus trifluoride was found to be 3,500 ppb by mass or less.
- the gas filling line was subjected to a purging process in which the inside was filled with nitrogen gas and then the inside was depressurized using a vacuum pump to create a vacuum state, and this was repeated. Then, 1 kg of phosphorus trifluoride was sent from the cylinder to the storage container via the purged gas filling line, resulting in a gas-filled storage container in which phosphorus trifluoride was filled in the storage container.
- the internal pressure (gauge pressure) of the resulting gas-filled storage container was 2.84 MPaG.
- the gas-filled storage container thus obtained was filled with phosphorus trifluoride and allowed to stand at 23°C for 30 days, after which the gas phase inside the gas-filled storage container was extracted from the upper outlet.
- concentrations of metal impurities contained in the extracted phosphorus trifluoride i.e., the concentrations of nickel, zinc, chromium, molybdenum, and tungsten, were measured using an inductively coupled plasma mass spectrometer. The results are shown in Table 1. Details of the method for measuring the concentrations of nickel, zinc, chromium, molybdenum, and tungsten using an inductively coupled plasma mass spectrometer are as follows.
- phosphorus trifluoride gas was extracted from the gas phase and passed through 100 g of nitric acid aqueous solution with a concentration of 1 mol/L at a flow rate of 100 mL/min, causing bubbling. This bubbling caused the phosphorus trifluoride to come into contact with the nitric acid aqueous solution, causing nickel, zinc, chromium, molybdenum, and tungsten to be absorbed into the nitric acid aqueous solution.
- the mass of the nitric acid aqueous solution after bubbling was 99 g (M1).
- the mass difference of the gas-filled storage container before and after bubbling was a decrease of 23 g (M2).
- the phosphorus trifluoride was extracted from the gas-filled storage container.
- the storage container from which the phosphorus trifluoride had been extracted was then subjected to a purging process in which the inside was filled with nitrogen gas, and then the inside was depressurized using a vacuum pump to create a vacuum state, which was repeated 30 times.
- the purged storage container was then cut using a laser cutting machine to obtain square pieces measuring 2 cm on a side. Using these pieces as measurement samples, X-ray photoelectron spectroscopy was performed on the inner surface of the storage container to measure the concentrations of copper, magnesium, calcium, and palladium in the metal material that forms the part of the storage container that comes into contact with the phosphorus fluoride. The results are shown in Table 1.
- the analytical device, analytical conditions, and sputtering conditions used in the XPS analysis are as follows: Analytical equipment: X-ray photoelectron spectrometer PHI5000VersaProbeII manufactured by ULVAC-PHI, Inc. Atmosphere: vacuum (less than 1.0 ⁇ 10 6 Pa) X-ray source: monochromated Al Ka (1486.6 eV) Spectrometer: electrostatic concentric hemispherical spectrometer X-ray beam diameter: 100 ⁇ m (25 W, 15 kV) Signal capture angle: 45.0° Pass energy: 23.5 eV Measurement energy range: Cu2p 933-953 eV Mg2p 50 eV Ca2p 347-351eV Pd3d 335-340eV Sputtering ion source: Ar2,500+ Sputtering acceleration voltage: 10 kV Sputtering area: 2 mm x 2 mm Sputtering time: 10 minutes
- Examples 2 and 3 and Comparative Examples 1 and 2 The same operations as in Example 1 were carried out, except that the concentrations of copper, magnesium, calcium, and palladium in the manganese steel forming the seamless container used as the storage container were different as shown in Table 1, and the concentrations of metal impurities in the phosphorus trifluoride gas in the gas-filled storage container after standing at 23° C. for 30 days were measured with an inductively coupled plasma mass spectrometer. The results are shown in Table 1. The concentrations of copper, magnesium, calcium, and palladium in the manganese steel were measured by XPS analysis of the inner surface of the storage container in the same manner as in Example 1.
- Examples 4, 5, 6 and Comparative Examples 3 and 4 The same operations as in Example 1 were carried out, except that a valve was attached to a seamless container having a volume of 10 L made of chromium-molybdenum steel to serve as the storage container, and the concentration of metal impurities in the phosphorus trifluoride gas in the gas-filled storage container after standing at 23° C. for 30 days was measured using an inductively coupled plasma mass spectrometer. The results are shown in Table 1. The concentrations of copper, magnesium, calcium, and palladium in the chromium-molybdenum steel were measured by subjecting the inner surface of the storage container to XPS analysis in the same manner as in Example 1, and the values are as shown in Table 1.
- Examples 7 and 8 and Comparative Examples 5 and 6) The same operations as in Example 1 were carried out, except that the type of phosphorus fluoride filled in the storage container and the seamless container used as the storage container were different as shown in Table 1, and the concentrations of metal impurities in the phosphorus pentafluoride gas in the gas-filled storage container after standing at 23° C. for 30 days were measured with an inductively coupled plasma mass spectrometer. The results are shown in Table 1. The concentrations of copper, magnesium, calcium, and palladium in the manganese steel and chromium molybdenum steel were measured by subjecting the inner surface of the storage container to XPS analysis in the same manner as in Example 1.
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Abstract
Description
本発明は、三フッ化リン（ＰＦ3）、五フッ化リン（ＰＦ5）、及び四フッ化二リン（Ｐ2Ｆ4）のうちの少なくとも一種であるフッ化リンの保管方法、保管容器、及びガス充填済み保管容器に関する。 The present invention relates to a method for storing phosphorus fluoride, which is at least one of phosphorus trifluoride (PF 3 ), phosphorus pentafluoride (PF 5 ), and diphosphorus tetrafluoride (P 2 F 4 ), a storage container, and a gas-filled storage container.
三フッ化リン、五フッ化リン、四フッ化二リン等のフッ化リンや、三フッ化塩素（ＣｌＦ3）、七フッ化ヨウ素（ＩＦ7）等の含フッ素ガスは、半導体製造用のドライエッチングガスとして利用されている。ドライエッチングにおいて微細な加工を安定的に行うためには、ドライエッチングガスが高純度（例えば９９．９体積％以上）であることが求められる。また、ドライエッチングガスは、保管容器に充填された状態で保管されるので、保管容器中で長期間にわたって高純度に維持される必要がある。特にドライエッチング中のパーティクル発生の起因となりうる金属不純物は、１質量ｐｐｍ以下の濃度に抑制する必要がある。 Phosphorus fluorides such as phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, and fluorine-containing gases such as chlorine trifluoride (ClF 3 ) and iodine heptafluoride (IF 7 ) are used as dry etching gases for semiconductor manufacturing. In order to stably perform fine processing in dry etching, the dry etching gas is required to have a high purity (for example, 99.9% by volume or more). In addition, since the dry etching gas is stored in a filled state in a storage container, it is necessary to maintain the high purity in the storage container for a long period of time. In particular, metal impurities that may cause particle generation during dry etching must be suppressed to a concentration of 1 mass ppm or less.
特許文献１には、含フッ素ガスを保管する保管容器の内面をフッ素化処理して、保管容器を形成する金属材料と含フッ素ガスとの反応を抑制する技術が開示されている。保管容器の内面を形成する金属材料と含フッ素ガスとを反応させるフッ素化処理を予め行った後に、保管容器に含フッ素ガスを充填するので、保管容器を形成する金属材料と充填された含フッ素ガスとの反応が生じにくく金属不純物の生成が抑えられる。そのため、充填された含フッ素ガスの純度の低下が、長期間にわたって抑制される。 Patent Document 1 discloses a technology in which the inner surface of a storage container that stores fluorine-containing gas is fluorinated to suppress reaction between the fluorine-containing gas and the metal material that forms the storage container. The storage container is filled with fluorine-containing gas after a fluorination treatment that causes a reaction between the metal material that forms the inner surface of the storage container and the fluorine-containing gas has been carried out in advance, so that reaction between the metal material that forms the storage container and the filled fluorine-containing gas is unlikely to occur, and the generation of metal impurities is suppressed. As a result, a decrease in the purity of the filled fluorine-containing gas is suppressed for a long period of time.
しかしながら、フッ化リンは配位子としての反応性が高いので、種々の金属原子と錯体を形成しうる。よって、長期間にわたる保管中に保管容器を形成する金属材料とフッ化リンが反応して錯体を形成し、金属不純物が生成するおそれがあるため、フッ化リンの純度が低下するおそれがあった。
本発明は、金属不純物の濃度の上昇が生じにくいフッ化リンの保管方法、保管容器、及びガス充填済み保管容器を提供することを課題とする。
However, since phosphorus fluoride is highly reactive as a ligand, it can form complexes with various metal atoms, and therefore, during long-term storage, phosphorus fluoride may react with the metal material forming the storage container to form a complex, which may generate metal impurities, resulting in a decrease in the purity of phosphorus fluoride.
An object of the present invention is to provide a method for storing phosphorus fluoride, a storage container, and a gas-filled storage container in which an increase in the concentration of metal impurities is unlikely to occur.
前記課題を解決するため、本発明の一態様は以下の［１］～［１０］の通りである。
［１］ 三フッ化リン、五フッ化リン、及び四フッ化二リンのうちの少なくとも一種であるフッ化リンの保管方法であって、
前記フッ化リンが接触する部分が金属材料で形成されている保管容器内に前記フッ化リンを保管し、
前記金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下であるフッ化リンの保管方法。
In order to solve the above problems, one aspect of the present invention is as follows [1] to [10].
[1] A method for storing phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, comprising:
storing the phosphorus fluoride in a storage container having a portion that comes into contact with the phosphorus fluoride made of a metal material;
A method for storing phosphorus fluoride, wherein the total concentration of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass % or less.
［２］ 前記金属材料がマンガン鋼及びクロムモリブデン鋼の少なくとも一方である［１］に記載のフッ化リンの保管方法。
［３］ 前記金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度は、Ｘ線光電子分光分析法によって測定されたものである［１］又は［２］に記載のフッ化リンの保管方法。
［４］ 前記フッ化リンの純度を９９．９０体積％以上として前記保管容器内に保管する［１］～［３］のいずれか一項に記載のフッ化リンの保管方法。
[2] The method for storing phosphorus fluoride according to [1], wherein the metal material is at least one of manganese steel and chromium molybdenum steel.
[3] The method for storing phosphorus fluoride according to [1] or [2], wherein the concentrations of copper, magnesium, calcium, and palladium contained in the metal material are measured by X-ray photoelectron spectroscopy.
[4] The method for storing phosphorus fluoride according to any one of [1] to [3], wherein the phosphorus fluoride is stored in the storage container with a purity of 99.90% by volume or more.
［５］ 三フッ化リン、五フッ化リン、及び四フッ化二リンのうちの少なくとも一種であるフッ化リンを保管するための保管容器であって、
前記フッ化リンが接触する部分が金属材料で形成されており、前記金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下であるフッ化リンの保管容器。
［６］ 前記金属材料がマンガン鋼及びクロムモリブデン鋼の少なくとも一方である［５］に記載のフッ化リンの保管容器。
[5] A storage container for storing phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride,
A storage container for phosphorus fluoride, the portion which comes into contact with the phosphorus fluoride being formed from a metal material, and the total concentration of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass % or less.
[6] The phosphorus fluoride storage container according to [5], wherein the metal material is at least one of manganese steel and chromium molybdenum steel.
［７］ 三フッ化リン、五フッ化リン、及び四フッ化二リンのうちの少なくとも一種であるフッ化リンが保管容器に充填されたガス充填済み保管容器であって、
前記保管容器の前記フッ化リンが接触する部分が金属材料で形成されており、前記金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下であるガス充填済み保管容器。
[7] A gas-filled storage container in which phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, is filled in the storage container,
A gas-filled storage container, wherein a portion of the storage container that comes into contact with the phosphorus fluoride is formed of a metal material, and the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass% or less.
［８］ 前記金属材料がマンガン鋼及びクロムモリブデン鋼の少なくとも一方である［７］に記載のガス充填済み保管容器。
［９］ 前記金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度は、Ｘ線光電子分光分析法によって測定されたものである［７］又は［８］に記載のガス充填済み保管容器。
［１０］ 前記フッ化リンの純度が９９．９０体積％以上である［７］～［９］のいずれか一項に記載のガス充填済み保管容器。
[8] The gas-filled storage container according to [7], wherein the metal material is at least one of manganese steel and chromium-molybdenum steel.
[9] The gas-filled storage container according to [7] or [8], wherein the concentrations of copper, magnesium, calcium, and palladium contained in the metal material are measured by X-ray photoelectron spectroscopy.
[10] The gas-filled storage container according to any one of [7] to [9], wherein the purity of the phosphorus fluoride is 99.90% by volume or more.
本発明に係るフッ化リンの保管方法、保管容器、及びガス充填済み保管容器でフッ化リンを保管すれば、フッ化リン中の金属不純物の濃度の上昇が生じにくい。 If phosphorus fluoride is stored using the phosphorus fluoride storage method, storage container, and gas-filled storage container of the present invention, the concentration of metal impurities in the phosphorus fluoride is unlikely to increase.
本発明の一実施形態について以下に説明する。なお、本実施形態は本発明の一例を示したものであって、本発明は本実施形態に限定されるものではない。また、本実施形態には種々の変更又は改良を加えることが可能であり、その様な変更又は改良を加えた形態も本発明に含まれ得る。 One embodiment of the present invention will be described below. Note that this embodiment is merely an example of the present invention, and the present invention is not limited to this embodiment. In addition, various modifications and improvements can be made to this embodiment, and forms incorporating such modifications or improvements can also be included in the present invention.
本実施形態に係るフッ化リンの保管方法は、三フッ化リン、五フッ化リン、及び四フッ化二リンのうちの少なくとも一種であるフッ化リンの保管方法であって、フッ化リンが接触する部分が金属材料で形成されている保管容器内にフッ化リンを保管する方法である。この金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和は０．８質量％以下である。 The method for storing phosphorus fluoride according to this embodiment is a method for storing phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, in which the phosphorus fluoride is stored in a storage container in which the portion that the phosphorus fluoride comes into contact with is made of a metal material. The sum of the concentrations of copper, magnesium, calcium, and palladium contained in this metal material is 0.8 mass% or less.
また、本実施形態に係るフッ化リンの保管容器は、三フッ化リン、五フッ化リン、及び四フッ化二リンのうちの少なくとも一種であるフッ化リンを保管するための保管容器であって、フッ化リンが接触する部分が金属材料で形成されている容器である。この金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和は０．８質量％以下である。 The phosphorus fluoride storage container according to this embodiment is a storage container for storing phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, and is a container in which the portion that comes into contact with the phosphorus fluoride is formed of a metal material. The sum of the concentrations of copper, magnesium, calcium, and palladium contained in this metal material is 0.8 mass% or less.
さらに、本実施形態に係るガス充填済み保管容器は、三フッ化リン、五フッ化リン、及び四フッ化二リンのうちの少なくとも一種であるフッ化リンが保管容器に充填されたガス充填済み保管容器であって、保管容器のフッ化リンが接触する部分が金属材料で形成されており、金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下である。 Furthermore, the gas-filled storage container according to this embodiment is a gas-filled storage container in which phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, is filled in the storage container, the portion of the storage container that comes into contact with the phosphorus fluoride is formed of a metal material, and the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass% or less.
保管容器のうちフッ化リンが接触する部分を形成する金属材料が、銅、マグネシウム、カルシウム、及びパラジウムのうちの少なくとも一種を含有していると、これら金属の触媒作用によって、前記金属材料に含有される金属原子とフッ化リンとが錯体を形成する反応が促進される。そのため、銅、マグネシウム、カルシウム、及びパラジウムのうちの少なくとも一種を含有する金属材料で形成されている保管容器にフッ化リンを保管すると、保管容器に保管している間に上記の錯体形成反応が進行して金属不純物が生成し、フッ化リンの純度が低下するおそれがある。 If the metal material forming the part of the storage container that comes into contact with phosphorus fluoride contains at least one of copper, magnesium, calcium, and palladium, the catalytic action of these metals promotes a reaction in which metal atoms contained in the metal material and phosphorus fluoride form a complex. Therefore, if phosphorus fluoride is stored in a storage container formed of a metal material containing at least one of copper, magnesium, calcium, and palladium, the above complex formation reaction may progress during storage in the storage container, resulting in the generation of metal impurities and a decrease in the purity of the phosphorus fluoride.
本実施形態に係るフッ化リンの保管方法、保管容器、及びガス充填済み保管容器は、保管容器のうちフッ化リンが接触する部分を形成する金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下であるので、長期間にわたる保管においても上記の錯体形成反応が進行しにくい。その結果、金属不純物が生成しにくいので、金属不純物の濃度の上昇が生じにくい（すなわち、フッ化リンの純度の低下が起こりにくい）。よって、フッ化リンを長期間にわたって安定して保管することができる。 In the phosphorus fluoride storage method, storage container, and gas-filled storage container according to this embodiment, the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material forming the portion of the storage container that comes into contact with the phosphorus fluoride is 0.8 mass% or less, so the above complex formation reaction is unlikely to proceed even during long-term storage. As a result, metal impurities are unlikely to be generated, and therefore the concentration of metal impurities is unlikely to increase (i.e., the purity of the phosphorus fluoride is unlikely to decrease). Therefore, the phosphorus fluoride can be stored stably for long periods of time.
フッ化リンと錯体を形成する金属としては、例えば、ニッケル（Ｎｉ）、亜鉛（Ｚｎ）、クロム（Ｃｒ）、モリブデン（Ｍｏ）、及びタングステン（Ｗ）が挙げられる。本実施形態に係るフッ化リンの保管方法、保管容器、及びガス充填済み保管容器によってフッ化リンを保管すれば、保管容器のうちフッ化リンが接触する部分を形成する金属材料がニッケル、亜鉛、クロム、モリブデン、及びタングステンのうちの少なくとも一種を含有していたとしても、ニッケル、亜鉛、クロム、モリブデン、及びタングステンとフッ化リンとが錯体を形成する反応が進行しにくい。よって、金属不純物が生成しにくいので、金属不純物の濃度の上昇が生じにくい。その結果、保管容器中で長期間にわたってフッ化リンを保管したとしても、フッ化リンのニッケル、亜鉛、クロム、モリブデン、及びタングステンの濃度の総和を１０００質量ｐｐｂ以下に維持することができる。 Metals that form complexes with phosphorus fluoride include, for example, nickel (Ni), zinc (Zn), chromium (Cr), molybdenum (Mo), and tungsten (W). When phosphorus fluoride is stored using the phosphorus fluoride storage method, storage container, and gas-filled storage container according to the present embodiment, even if the metal material forming the portion of the storage container that comes into contact with the phosphorus fluoride contains at least one of nickel, zinc, chromium, molybdenum, and tungsten, the reaction of nickel, zinc, chromium, molybdenum, and tungsten with phosphorus fluoride to form complexes is unlikely to proceed. Therefore, metal impurities are unlikely to be generated, and the concentration of metal impurities is unlikely to increase. As a result, even if phosphorus fluoride is stored in the storage container for a long period of time, the sum of the concentrations of nickel, zinc, chromium, molybdenum, and tungsten in the phosphorus fluoride can be maintained at 1000 mass ppb or less.
フッ化リンのニッケル、亜鉛、クロム、モリブデン、及びタングステンの濃度の総和は１０００質量ｐｐｂ以下に維持することが好ましいが、８００質量ｐｐｂ以下に維持することがより好ましく、５００質量ｐｐｂ以下に維持することがさらに好ましい。フッ化リンのニッケル、亜鉛、クロム、モリブデン、及びタングステンの濃度の総和が１０００質量ｐｐｂ以下であると、フッ化リンをドライエッチングガスとして使用した際にエッチング性能が低くなることが避けられる傾向にある。フッ化リンのニッケル、亜鉛、クロム、モリブデン、及びタングステンの濃度の総和が１０００質量ｐｐｂを超えている場合は、フッ化リンと保管容器が接触する部分において、該部分を形成する金属材料とフッ化リンとの錯体形成反応が進行していることが考えられる。 The sum of the concentrations of nickel, zinc, chromium, molybdenum, and tungsten in phosphorus fluoride is preferably maintained at 1000 mass ppb or less, more preferably at 800 mass ppb or less, and even more preferably at 500 mass ppb or less. If the sum of the concentrations of nickel, zinc, chromium, molybdenum, and tungsten in phosphorus fluoride is 1000 mass ppb or less, it tends to avoid poor etching performance when phosphorus fluoride is used as a dry etching gas. If the sum of the concentrations of nickel, zinc, chromium, molybdenum, and tungsten in phosphorus fluoride exceeds 1000 mass ppb, it is believed that a complex formation reaction between phosphorus fluoride and the metal material forming the part where the phosphorus fluoride comes into contact with the storage container is progressing.
なお、本実施形態に係るフッ化リンの保管方法、保管容器、及びガス充填済み保管容器は、フッ化リンを保管する保管容器のうちフッ化リンが接触する部分を形成する金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和を０．８質量％以下とするものであるが、前記金属材料には、銅、マグネシウム、カルシウム、及びパラジウムのうちの少なくとも一種が含有されていてもよいし（すなわち、前記濃度の総和が０質量％超過０．８質量％以下でもよい）、全く含有されていなくてもよい（すなわち、前記濃度の総和が０質量％でもよい）。 In addition, the phosphorus fluoride storage method, storage container, and gas-filled storage container according to this embodiment are such that the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material forming the portion of the storage container that stores phosphorus fluoride and that comes into contact with the phosphorus fluoride is 0.8 mass% or less. However, the metal material may contain at least one of copper, magnesium, calcium, and palladium (i.e., the sum of the concentrations may be more than 0 mass% and 0.8 mass% or less), or may not contain any of these elements at all (i.e., the sum of the concentrations may be 0 mass%).
以下、本実施形態に係るフッ化リンの保管方法、保管容器、及びガス充填済み保管容器について、さらに詳細に説明する。
〔フッ化リン〕
フッ化リンは、上記のように、三フッ化リン、五フッ化リン、及び四フッ化二リンのうちの少なくとも一種である。すなわち、フッ化リンは、三フッ化リン、五フッ化リン、及び四フッ化二リンのうちのいずれか一種であってもよいし、二種の混合物であってもよいし、三種の混合物であってもよい。
The phosphorus fluoride storage method, storage container, and gas-filled storage container according to this embodiment will be described in further detail below.
[Phosphorus fluoride]
As described above, the phosphorus fluoride is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride. That is, the phosphorus fluoride may be any one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, or may be a mixture of two or three of them.
フッ化リンが、三フッ化リン、五フッ化リン、及び四フッ化二リンのうちの二種又は三種の混合物である場合は、最も含有量が多い成分である主成分の含有量は９９モル％以上であることが好ましく、９９．９モル％以上であることがより好ましく、９９．９９モル％以上であることがさらに好ましい。また、主成分以外の成分の合計の含有量は０．１モル％以下であることが好ましく、０．０１モル％以下であることがより好ましく、０．００１モル％以下であることがさらに好ましい。 When the phosphorus fluoride is a mixture of two or three of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, the content of the main component, which is the component with the greatest content, is preferably 99 mol% or more, more preferably 99.9 mol% or more, and even more preferably 99.99 mol% or more. The total content of components other than the main component is preferably 0.1 mol% or less, more preferably 0.01 mol% or less, and even more preferably 0.001 mol% or less.
フッ化リンを保管容器に保管する際には、フッ化リンのみからなるガスを保管容器に保管してもよいし、フッ化リンと希釈ガスを含有する混合ガスを保管容器に保管してもよい。また、フッ化リンの一部又は全部を液化させて保管容器に保管してもよい。希釈ガスとしては、窒素ガス（Ｎ2）、ヘリウム（Ｈｅ）、ネオン（Ｎｅ）、アルゴン（Ａｒ）、クリプトン（Ｋｒ）、及びキセノン（Ｘｅ）から選ばれる少なくとも一種を用いることができる。希釈ガスの含有量は、保管容器に保管するガスの総量に対して９０体積％以下であることが好ましく、５０体積％以下であることがより好ましい。 When storing phosphorus fluoride in a storage container, a gas consisting of phosphorus fluoride alone may be stored in the storage container, or a mixed gas containing phosphorus fluoride and a diluent gas may be stored in the storage container. Also, a part or all of phosphorus fluoride may be liquefied and stored in the storage container. As the diluent gas, at least one selected from nitrogen gas (N 2 ), helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe) may be used. The content of the diluent gas is preferably 90% by volume or less, more preferably 50% by volume or less, of the total amount of gas stored in the storage container.
なお、本実施形態に係るフッ化リンの保管方法、保管容器、及びガス充填済み保管容器においては、純度が９９．９０体積％以上であるフッ化リンを、保管容器内に保管することが好ましい。保管容器内へ導入するフッ化リンの純度が９９．９０体積％以上であれば、エッチング対象物を非エッチング対象物に比べて選択的に且つ十分なエッチング速度でエッチングできるという効果が奏される。 In the phosphorus fluoride storage method, storage container, and gas-filled storage container according to this embodiment, it is preferable to store phosphorus fluoride with a purity of 99.90% by volume or more in the storage container. If the purity of the phosphorus fluoride introduced into the storage container is 99.90% by volume or more, the effect of being able to etch the object to be etched selectively and at a sufficient etching rate compared to the object not to be etched is achieved.
〔保管容器〕
フッ化リンを保管又は充填する保管容器については、フッ化リンを収容し密封することができ、且つ、フッ化リンが接触する部分が金属材料で形成されており、この金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下であるならば、形状、大きさ等は特に限定されるものではない。また、保管容器のうちフッ化リンが接触しない部分の材質は、特に限定されるものではない。ただし、保管容器は、フッ化リンに対して耐食性を有することが好ましい。前記金属材料の例としては、耐食性の観点から、マンガン鋼、ステンレス鋼、クロムモリブデン鋼、ハステロイ（登録商標）、インコネル（登録商標）、モネル（登録商標）等が挙げられる。前記金属材料は、マンガン鋼及びクロムモリブデン鋼の少なくとも一方であってもよい。
[Storage container]
The shape, size, etc. of the storage container for storing or filling phosphorus fluoride are not particularly limited as long as the storage container can contain and seal phosphorus fluoride, the portion that contacts phosphorus fluoride is formed of a metal material, and the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass% or less. The material of the portion of the storage container that does not contact phosphorus fluoride is not particularly limited. However, it is preferable that the storage container has corrosion resistance against phosphorus fluoride. Examples of the metal material include manganese steel, stainless steel, chromium molybdenum steel, Hastelloy (registered trademark), Inconel (registered trademark), Monel (registered trademark), etc., from the viewpoint of corrosion resistance. The metal material may be at least one of manganese steel and chromium molybdenum steel.
マンガン鋼製の保管容器、クロムモリブデン鋼製の保管容器としては、例えば、ＪＩＳ規格のＪＩＳ Ｇ３４２９（高圧ガス容器用継目無鋼管）のＳＴＨ１１、ＳＴＨ１２（マンガン鋼鋼管）やＳＴＨ２１、ＳＴＨ２２（クロムモリブデン鋼鋼管）で定められた鋼管から製造された容器がある。 Storage containers made of manganese steel and chrome-molybdenum steel include, for example, containers manufactured from steel pipes specified in the JIS standard JIS G3429 (seamless steel pipes for high-pressure gas containers) STH11, STH12 (manganese steel pipes) and STH21, STH22 (chrome-molybdenum steel pipes).
ただし、これらの規格には銅の項目が無く、マンガン鋼やクロムモリブデン鋼に含有される銅の濃度は不明であるため、これらの規格を満たすだけでは不十分である。市販されており、且つ、ＳＴＨ１２規格を満たす複数のボンベの内面を分析した結果、銅の濃度はボンベによって様々であった。よって、一般的なマンガン鋼、クロムモリブデン鋼で形成された容器を、本発明において保管容器として用いる場合は、銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下であるものを選別して用いる必要がある。 However, these standards do not include an item for copper, and the copper concentration in manganese steel and chrome molybdenum steel is unknown, so simply meeting these standards is insufficient. Analysis of the inner surfaces of several commercially available cylinders that meet the STH12 standard revealed that the copper concentration varied from cylinder to cylinder. Therefore, when using containers made of general manganese steel or chrome molybdenum steel as storage containers in the present invention, it is necessary to select those with a total copper, magnesium, calcium, and palladium concentration of 0.8 mass% or less.
なお、保管容器には弁も含まれるが、弁についても保管容器と同様にマンガン鋼、ステンレス鋼、クロムモリブデン鋼で形成されていることが好ましい。フッ化リンが直接接触しないような構造の弁であれば、真鍮、モネル（登録商標）等の銅合金で形成された弁であっても使用することができる。 The storage container also includes a valve, and like the storage container, the valve is preferably made of manganese steel, stainless steel, or chrome molybdenum steel. Valves made of brass or copper alloys such as Monel (registered trademark) can also be used as long as they are designed not to come into direct contact with phosphorus fluoride.
〔金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウム〕
本実施形態に係るフッ化リンの保管方法、保管容器、及びガス充填済み保管容器における前記金属材料は、銅、マグネシウム、カルシウム、及びパラジウムのうちの少なくとも一種を含有するか又は含有しないが、前記含有する場合の銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下であるため、前述したようにフッ化リンとニッケル、亜鉛、クロム、モリブデン、及びタングステンとの錯体形成反応が進行しにくい。ここで、前記含有しないとは、Ｘ線光電子分光分析法（Ｘ－ｒａｙ Ｐｈｏｔｏｅｌｅｃｔｒｏｎ Ｓｐｅｃｔｒｏｓｃｏｐｙ：ＸＰＳ分析法）で定量することができない場合を意味する。すなわち、前記金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度は、Ｘ線光電子分光分析法によって測定することができる。より具体的には、実施例に記載の方法で測定することができる。
[Copper, magnesium, calcium, and palladium contained in metal materials]
The metal material in the storage method, storage container, and gas-filled storage container of phosphorus fluoride according to this embodiment contains or does not contain at least one of copper, magnesium, calcium, and palladium, but when it contains, the sum of the concentrations of copper, magnesium, calcium, and palladium is 0.8 mass% or less, so that the complex formation reaction between phosphorus fluoride and nickel, zinc, chromium, molybdenum, and tungsten does not proceed easily as described above. Here, the absence of the above means that it is not possible to quantitatively determine the concentration by X-ray photoelectron spectroscopy (XPS analysis). That is, the concentrations of copper, magnesium, calcium, and palladium contained in the metal material can be measured by X-ray photoelectron spectroscopy. More specifically, they can be measured by the method described in the examples.
保管中のフッ化リンとニッケル、亜鉛、クロム、モリブデン、及びタングステンとの錯体形成反応を進行しにくくするためには、前記金属材料が含有する銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下である必要があるが、０．４質量％以下であることが好ましく、０．２質量％以下であることがより好ましい。
なお、銅、マグネシウム、カルシウム、及びパラジウムは、保管容器の原料である前記金属材料や、保管容器を製造する際に使用する保管容器の製造装置等に由来して保管容器に混入すると考えられる。
In order to prevent the progression of complex formation reactions between phosphorus fluoride and nickel, zinc, chromium, molybdenum, and tungsten during storage, the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material must be 0.8 mass% or less, preferably 0.4 mass% or less, and more preferably 0.2 mass% or less.
Incidentally, copper, magnesium, calcium, and palladium are thought to be contaminated into the storage containers due to the metal materials that are the raw materials of the storage containers, or due to the manufacturing equipment for the storage containers that is used in manufacturing the storage containers.
〔金属の濃度が低いフッ化リンの製造方法〕
本実施形態に係るフッ化リンの保管方法及び本実施形態に係るガス充填済み保管容器において保管容器に充填されるフッ化リン（充填前のフッ化リン）についても、含有する銅、マグネシウム、カルシウム、及びパラジウムの濃度が低いことが好ましい。
[Method for producing phosphorus fluoride with low metal concentration]
In the phosphorus fluoride storage method of this embodiment and the gas-filled storage container of this embodiment, it is preferable that the phosphorus fluoride (phosphorus fluoride before filling) filled into the storage container contains low concentrations of copper, magnesium, calcium, and palladium.
銅、マグネシウム、カルシウム、及びパラジウムの濃度が低いフッ化リンを製造する方法としては、例えば、銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が大きいフッ化リンから、銅、マグネシウム、カルシウム、及びパラジウムを除去する方法が挙げられる。フッ化リンから銅、マグネシウム、カルシウム、及びパラジウムを除去する方法は特に限定されるものではなく、公知の方法を採用することができる。例えば、フィルターを用いる方法、吸着剤を用いる方法、蒸留等が挙げられる。 An example of a method for producing phosphorus fluoride with low concentrations of copper, magnesium, calcium, and palladium is a method for removing copper, magnesium, calcium, and palladium from phosphorus fluoride having a high sum of copper, magnesium, calcium, and palladium concentrations. There is no particular limitation on the method for removing copper, magnesium, calcium, and palladium from phosphorus fluoride, and any known method can be used. Examples include a method using a filter, a method using an adsorbent, distillation, etc.
フッ化リンガスを選択的に通過させるフィルターの材質は、フッ化リンへの金属成分の混入を避けるためには、樹脂が好ましく、ポリテトラフルオロエチレンが特に好ましい。フィルターの平均孔径は０．０１μｍ以上３０μｍ以下が好ましく、０．１μｍ以上１０μｍ以下がより好ましい。平均孔径が上記範囲内であれば、銅、マグネシウム、カルシウム、及びパラジウムを十分に除去すること可能であるとともに、フッ化リンガスの十分な流量を確保して高い生産性を実現できる。 The material of the filter that selectively passes the phosphorus fluoride gas is preferably a resin, and polytetrafluoroethylene is particularly preferred, in order to prevent metal components from being mixed into the phosphorus fluoride. The average pore size of the filter is preferably 0.01 μm or more and 30 μm or less, and more preferably 0.1 μm or more and 10 μm or less. If the average pore size is within the above range, it is possible to sufficiently remove copper, magnesium, calcium, and palladium, and a sufficient flow rate of the phosphorus fluoride gas can be secured, thereby achieving high productivity.
フィルターを通過させるフッ化リンガスの流量は、フィルター面積１ｃｍ2当たり、３ｍＬ／ｍｉｎ以上３００ｍＬ／ｍｉｎ以下とすることが好ましく、１０ｍＬ／ｍｉｎ以上５０ｍＬ／ｍｉｎ以下とすることがより好ましい。フッ化リンガスの流量が上記範囲内であれば、フッ化リンガスが高圧となることが抑制されて、フッ化リンガスの漏洩リスクが低くなるとともに、高い生産性を実現できる。なお、フッ化リンが含有する銅、マグネシウム、カルシウム、及びパラジウムの濃度は、誘導結合プラズマ質量分析計（ＩＣＰ－ＭＳ）で定量することができる。 The flow rate of the fluorinated gas passing through the filter is preferably 3 mL/min to 300 mL/min, more preferably 10 mL/min to 50 mL/min per cm2 of filter area. If the flow rate of the fluorinated gas is within the above range, the fluorinated gas is prevented from becoming high pressure, the risk of leakage of the fluorinated gas is reduced, and high productivity can be achieved. The concentrations of copper, magnesium, calcium, and palladium contained in the fluorinated phosphorus can be quantified by an inductively coupled plasma mass spectrometer (ICP-MS).
〔保管時の圧力条件〕
本実施形態に係るフッ化リンの保管方法及び本実施形態に係るガス充填済み保管容器における保管時の圧力条件は、保管容器内にフッ化リンを密閉して保管できるならば特に限定されるものではないが、０．１５ＭＰａ以上１５ＭＰａ以下とすることが好ましく、０．３ＭＰａ以上９ＭＰａ以下とすることがより好ましい。圧力条件が上記の範囲内であれば、保管容器をドライエッチング装置に接続したときに、加温せずにフッ化リンを流通させることができる。
[Pressure conditions during storage]
The pressure conditions during storage in the method for storing phosphorus fluoride according to this embodiment and the gas-filled storage container according to this embodiment are not particularly limited as long as phosphorus fluoride can be stored hermetically in the storage container, but are preferably 0.15 MPa or more and 15 MPa or less, and more preferably 0.3 MPa or more and 9 MPa or less. If the pressure conditions are within the above range, phosphorus fluoride can be circulated without heating when the storage container is connected to a dry etching device.
〔保管時の温度条件〕
本実施形態に係るフッ化リンの保管方法及び本実施形態に係るガス充填済み保管容器における保管時の温度条件は特に限定されるものではないが、－２０℃以上５０℃以下とすることが好ましく、０℃以上４０℃以下とすることがより好ましい。保管時の温度が－２０℃以上であれば、保管容器の変形が生じにくいので、保管容器の気密性が失われて酸素、水等が保管容器内に混入する可能性が低い。酸素、水等が混入すると、フッ化リンの分解反応が促進されるおそれがある。一方、保管時の温度が５０℃以下であれば、フッ化リンとニッケル、亜鉛、クロム、モリブデン、及びタングステンとの錯体形成反応が進行しにくい。
[Storage temperature conditions]
The temperature conditions during storage in the method for storing phosphorus fluoride according to this embodiment and the gas-filled storage container according to this embodiment are not particularly limited, but are preferably -20°C or higher and 50°C or lower, and more preferably 0°C or higher and 40°C or lower. If the storage temperature is -20°C or higher, the storage container is unlikely to deform, so there is a low possibility that the airtightness of the storage container will be lost and oxygen, water, etc. will be mixed into the storage container. If oxygen, water, etc. are mixed in, the decomposition reaction of phosphorus fluoride may be promoted. On the other hand, if the storage temperature is 50°C or lower, the complex formation reaction between phosphorus fluoride and nickel, zinc, chromium, molybdenum, and tungsten will not proceed easily.
〔エッチング〕
本実施形態に係るフッ化リンの保管方法、保管容器、及びガス充填済み保管容器で保管されるフッ化リンは、エッチングガスとして用いることが可能である。そして、本実施形態に係るフッ化リンの保管方法、保管容器、及びガス充填済み保管容器で保管されるフッ化リンを含有するエッチングガスは、プラズマを用いるプラズマエッチング、プラズマを用いないプラズマレスエッチングのいずれにも使用することができる。
〔etching〕
The phosphorus fluoride stored in the storage method, storage container, and gas-filled storage container according to the present embodiment can be used as an etching gas. The phosphorus fluoride-containing etching gas stored in the storage method, storage container, and gas-filled storage container according to the present embodiment can be used in both plasma etching using plasma and plasmaless etching not using plasma.
プラズマエッチングとしては、例えば、反応性イオンエッチング（ＲＩＥ：Ｒｅａｃｔｉｖｅ Ｉｏｎ Ｅｔｃｈｉｎｇ）、誘導結合型プラズマ（ＩＣＰ：Ｉｎｄｕｃｔｉｖｅｌｙ Ｃｏｕｐｌｅｄ Ｐｌａｓｍａ）エッチング、容量結合型プラズマ（ＣＣＰ：Ｃａｐａｃｉｔｉｖｅｌｙ Ｃｏｕｐｌｅｄ Ｐｌａｓｍａ）エッチング、電子サイクロトロン共鳴（ＥＣＲ：Ｅｌｅｃｔｒｏｎ Ｃｙｃｌｏｔｒｏｎ Ｒｅｓｏｎａｎｃｅ）プラズマエッチング、マイクロ波プラズマエッチングが挙げられる。
また、プラズマエッチングにおいては、プラズマは被エッチング部材が設置されたチャンバー内で発生させてもよいし、プラズマ発生室と被エッチング部材を設置するチャンバーとを分けてもよい（すなわち、遠隔プラズマを用いてもよい）。
Examples of plasma etching include reactive ion etching (RIE), inductively coupled plasma (ICP) etching, capacitively coupled plasma (CCP) etching, electron cyclotron resonance (ECR) plasma etching, and microwave plasma etching.
In plasma etching, the plasma may be generated in a chamber in which the member to be etched is placed, or the plasma generation chamber may be separate from the chamber in which the member to be etched is placed (i.e., remote plasma may be used).
以下に実施例及び比較例を示して、本発明をさらに具体的に説明する。
（実施例１）
マンガン鋼で形成されている容量１０Ｌの継ぎ目なし容器を用意し、その内面に対してショットブラスト、酸洗浄、及び水洗をこの記載順で行った後に、さらに乾燥を行った。そして、乾燥した容器に弁を取り付けて保管容器とした。この弁は、銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．００５質量％未満であるＳＵＳ３１６Ｌで形成されている。
The present invention will be described in more detail below with reference to examples and comparative examples.
Example 1
A seamless container with a volume of 10 L made of manganese steel was prepared, and its inner surface was shot blasted, acid washed, and washed with water in the order described, and then dried. A valve was attached to the dried container to prepare a storage container. The valve was made of SUS316L, which has a total concentration of copper, magnesium, calcium, and palladium of less than 0.005 mass%.
この保管容器を１６０℃に加熱し、真空ポンプを用いて保管容器の内部を減圧して真空状態にした。そして、内部を真空状態にした保管容器を、三フッ化リンが充填されたボンベを備えるガス充填ラインに接続した。三フッ化リンが充填されたボンベは、銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．００５質量％未満であるＳＵＳ３１６で形成されている。 The storage container was heated to 160°C, and the inside of the storage container was depressurized using a vacuum pump to create a vacuum. The storage container with the inside in a vacuum state was then connected to a gas filling line equipped with a cylinder filled with phosphorus trifluoride. The cylinder filled with phosphorus trifluoride was made of SUS316, with the total concentration of copper, magnesium, calcium, and palladium being less than 0.005% by mass.
また、このボンベに充填されている三フッ化リンを、ガスクロマトグラフィーによって分析したところ、その純度は９９．９５体積％であった。さらに、このボンベに充填されている三フッ化リンを、誘導結合プラズマ質量分析計によって分析したところ、三フッ化リンに含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和は３５００質量ｐｐｂ以下であった。 In addition, when the phosphorus trifluoride filled in the cylinder was analyzed by gas chromatography, its purity was found to be 99.95% by volume. Furthermore, when the phosphorus trifluoride filled in the cylinder was analyzed by inductively coupled plasma mass spectrometry, the total concentration of copper, magnesium, calcium, and palladium contained in the phosphorus trifluoride was found to be 3,500 ppb by mass or less.
次に、ガス充填ラインに対して、内部に窒素ガスを満たした後に真空ポンプを用いて内部を減圧して真空状態にすることを繰り返すパージ処理を施した。そして、パージ処理を施したガス充填ラインを介して、ボンベから三フッ化リン１ｋｇを保管容器に送って、保管容器に三フッ化リンが充填されてなるガス充填済み保管容器を得た。得られたガス充填済み保管容器の内圧（ゲージ圧）は、２．８４ＭＰaＧであった。 Next, the gas filling line was subjected to a purging process in which the inside was filled with nitrogen gas and then the inside was depressurized using a vacuum pump to create a vacuum state, and this was repeated. Then, 1 kg of phosphorus trifluoride was sent from the cylinder to the storage container via the purged gas filling line, resulting in a gas-filled storage container in which phosphorus trifluoride was filled in the storage container. The internal pressure (gauge pressure) of the resulting gas-filled storage container was 2.84 MPaG.
このようにして得られたガス充填済み保管容器を、三フッ化リンを充填してから２３℃で３０日間静置した後に、ガス充填済み保管容器内の気相部を上側出口から抜き出した。そして、抜き出した三フッ化リンに含有される金属不純物の濃度、すなわちニッケル、亜鉛、クロム、モリブデン、及びタングステンの濃度を誘導結合プラズマ質量分析計で測定した。結果を表１に示す。なお、誘導結合プラズマ質量分析計を用いたニッケル、亜鉛、クロム、モリブデン、及びタングステンの濃度の測定方法の詳細は、以下のとおりである。 The gas-filled storage container thus obtained was filled with phosphorus trifluoride and allowed to stand at 23°C for 30 days, after which the gas phase inside the gas-filled storage container was extracted from the upper outlet. The concentrations of metal impurities contained in the extracted phosphorus trifluoride, i.e., the concentrations of nickel, zinc, chromium, molybdenum, and tungsten, were measured using an inductively coupled plasma mass spectrometer. The results are shown in Table 1. Details of the method for measuring the concentrations of nickel, zinc, chromium, molybdenum, and tungsten using an inductively coupled plasma mass spectrometer are as follows.
ガス充填済み保管容器の液相の三フッ化リンを－７８℃で気化させながら、その気相部から三フッ化リンのガスを抜き出し、濃度１ｍｏｌ／Ｌの硝酸水溶液１００ｇに１００ｍＬ／ｍｉｎの流量で流通させ、バブリングさせた。このバブリングにより、三フッ化リンと硝酸水溶液を接触させて、硝酸水溶液にニッケル、亜鉛、クロム、モリブデン、及びタングステンを吸収させた。バブリング後の硝酸水溶液の質量は９９ｇ（Ｍ１）であった。また、バブリング前後のガス充填済み保管容器の質量差は２３ｇ（Ｍ２）減少であった。 While the phosphorus trifluoride in the liquid phase of the gas-filled storage container was vaporized at -78°C, phosphorus trifluoride gas was extracted from the gas phase and passed through 100 g of nitric acid aqueous solution with a concentration of 1 mol/L at a flow rate of 100 mL/min, causing bubbling. This bubbling caused the phosphorus trifluoride to come into contact with the nitric acid aqueous solution, causing nickel, zinc, chromium, molybdenum, and tungsten to be absorbed into the nitric acid aqueous solution. The mass of the nitric acid aqueous solution after bubbling was 99 g (M1). The mass difference of the gas-filled storage container before and after bubbling was a decrease of 23 g (M2).
バブリング後の硝酸水溶液１０ｇ（Ｍ３）を採取し、メスフラスコを用いて超純水で１００ｍＬ（Ｖ）に希釈した。希釈した硝酸水溶液中の各種金属原子（ニッケル、亜鉛、クロム、モリブデン、及びタングステン）の濃度を誘導結合プラズマ質量分析計で測定し、その測定値（ｃ１、単位：ｇ／ｍＬ）と下記式とによって、三フッ化リン中の各種金属原子の濃度（Ｃ、単位：ｇ／ｇ）を算出した。
Ｃ＝｛（ｃ１×Ｖ）×（Ｍ１／Ｍ３）｝／Ｍ２
10 g of the aqueous nitric acid solution after bubbling (M3) was collected and diluted with ultrapure water to 100 mL (V) using a measuring flask. The concentrations of various metal atoms (nickel, zinc, chromium, molybdenum, and tungsten) in the diluted aqueous nitric acid solution were measured using an inductively coupled plasma mass spectrometer, and the concentrations of various metal atoms in phosphorus trifluoride (C, unit: g/g) were calculated using the measured values (c1, unit: g/mL) and the following formula.
C={(c1×V)×(M1/M3)}/M2
三フッ化リンの各種金属原子の濃度を測定し終わったら、ガス充填済み保管容器から三フッ化リンを抜き出した。そして、三フッ化リンを抜き出した保管容器に対して、内部に窒素ガスを満たした後に真空ポンプを用いて内部を減圧して真空状態にすることを３０回繰り返すパージ処理を施した。 After measuring the concentrations of various metal atoms in phosphorus trifluoride, the phosphorus trifluoride was extracted from the gas-filled storage container. The storage container from which the phosphorus trifluoride had been extracted was then subjected to a purging process in which the inside was filled with nitrogen gas, and then the inside was depressurized using a vacuum pump to create a vacuum state, which was repeated 30 times.
次に、パージ処理を施した保管容器を、レーザー切断機を用いて切断して、一辺２ｃｍの正方形状の部材を得た。この部材を測定試料として用いて、保管容器の内面のＸ線光電子分光分析を行い、保管容器のうちフッ化リンが接触する部分を形成する金属材料の銅、マグネシウム、カルシウム、及びパラジウムの濃度をそれぞれ測定した。結果を表１に示す。 The purged storage container was then cut using a laser cutting machine to obtain square pieces measuring 2 cm on a side. Using these pieces as measurement samples, X-ray photoelectron spectroscopy was performed on the inner surface of the storage container to measure the concentrations of copper, magnesium, calcium, and palladium in the metal material that forms the part of the storage container that comes into contact with the phosphorus fluoride. The results are shown in Table 1.
なお、ＸＰＳ分析に使用した分析装置、分析条件、及びスパッタ条件は、以下のとおりである。
分析装置：アルバック・ファイ株式会社製Ｘ線光電子分光分析装置ＰＨＩ５０００ＶｅｒｓａＰｒｏｂｅＩＩ
雰囲気：真空（１．０×１０6Ｐａ未満）
Ｘ線源：単色化Ａｌ Ｋａ（１４８６．６ｅＶ）
分光器：静電同心半球型分光器
Ｘ線ビーム径：１００μｍ（２５Ｗ、１５ｋＶ）
信号の取り込み角：４５．０°
パスエネルギー：２３．５ｅＶ
測定エネルギー範囲：Ｃｕ２ｐ ９３３－９５３ｅＶ
Ｍｇ２ｐ ５０ｅＶ
Ｃａ２ｐ ３４７－３５１ｅＶ
Ｐｄ３ｄ ３３５－３４０ｅＶ
スパッタのイオン源：Ａｒ２，５００＋
スパッタの加速電圧：１０ｋＶ
スパッタ領域：２ｍｍ×２ｍｍ
スパッタ時間：１０分
The analytical device, analytical conditions, and sputtering conditions used in the XPS analysis are as follows:
Analytical equipment: X-ray photoelectron spectrometer PHI5000VersaProbeII manufactured by ULVAC-PHI, Inc.
Atmosphere: vacuum (less than 1.0×10 6 Pa)
X-ray source: monochromated Al Ka (1486.6 eV)
Spectrometer: electrostatic concentric hemispherical spectrometer X-ray beam diameter: 100 μm (25 W, 15 kV)
Signal capture angle: 45.0°
Pass energy: 23.5 eV
Measurement energy range: Cu2p 933-953 eV
Mg2p 50 eV
Ca2p 347-351eV
Pd3d 335-340eV
Sputtering ion source: Ar2,500+
Sputtering acceleration voltage: 10 kV
Sputtering area: 2 mm x 2 mm
Sputtering time: 10 minutes
（実施例２、３及び比較例１、２）
保管容器として用いた継ぎ目なし容器を形成するマンガン鋼の銅、マグネシウム、カルシウム、及びパラジウムの濃度が、表１に示すとおり異なる点以外は、実施例１と同様の操作を行って、２３℃で３０日間静置した後のガス充填済み保管容器内の三フッ化リンガスの金属不純物の濃度を誘導結合プラズマ質量分析計で測定した。結果を表１に示す。なお、マンガン鋼の銅、マグネシウム、カルシウム、及びパラジウムの濃度は、実施例１と同様に保管容器の内面のＸＰＳ分析を行って測定したものである。
(Examples 2 and 3 and Comparative Examples 1 and 2)
The same operations as in Example 1 were carried out, except that the concentrations of copper, magnesium, calcium, and palladium in the manganese steel forming the seamless container used as the storage container were different as shown in Table 1, and the concentrations of metal impurities in the phosphorus trifluoride gas in the gas-filled storage container after standing at 23° C. for 30 days were measured with an inductively coupled plasma mass spectrometer. The results are shown in Table 1. The concentrations of copper, magnesium, calcium, and palladium in the manganese steel were measured by XPS analysis of the inner surface of the storage container in the same manner as in Example 1.
（実施例４、５、６及び比較例３、４）
クロムモリブデン鋼で形成されている容量１０Ｌの継ぎ目なし容器に弁を取り付けて保管容器とした点以外は、実施例１と同様の操作を行って、２３℃で３０日間静置した後のガス充填済み保管容器内の三フッ化リンガスの金属不純物の濃度を誘導結合プラズマ質量分析計で測定した。結果を表１に示す。なお、クロムモリブデン鋼の銅、マグネシウム、カルシウム、及びパラジウムの濃度は、実施例１と同様に保管容器の内面のＸＰＳ分析を行って測定したものであり、その数値は表１に示すとおりである。
(Examples 4, 5, 6 and Comparative Examples 3 and 4)
The same operations as in Example 1 were carried out, except that a valve was attached to a seamless container having a volume of 10 L made of chromium-molybdenum steel to serve as the storage container, and the concentration of metal impurities in the phosphorus trifluoride gas in the gas-filled storage container after standing at 23° C. for 30 days was measured using an inductively coupled plasma mass spectrometer. The results are shown in Table 1. The concentrations of copper, magnesium, calcium, and palladium in the chromium-molybdenum steel were measured by subjecting the inner surface of the storage container to XPS analysis in the same manner as in Example 1, and the values are as shown in Table 1.
（実施例７、８及び比較例５、６）
保管容器に充填するフッ化リンの種類及び保管容器として用いた継ぎ目なし容器が、表１に示すとおり異なる点以外は、実施例１と同様の操作を行って、２３℃で３０日間静置した後のガス充填済み保管容器内の五フッ化リンガスの金属不純物の濃度を誘導結合プラズマ質量分析計で測定した。結果を表１に示す。なお、マンガン鋼及びクロムモリブデン鋼の銅、マグネシウム、カルシウム、及びパラジウムの濃度は、実施例１と同様に保管容器の内面のＸＰＳ分析を行って測定したものである。
(Examples 7 and 8 and Comparative Examples 5 and 6)
The same operations as in Example 1 were carried out, except that the type of phosphorus fluoride filled in the storage container and the seamless container used as the storage container were different as shown in Table 1, and the concentrations of metal impurities in the phosphorus pentafluoride gas in the gas-filled storage container after standing at 23° C. for 30 days were measured with an inductively coupled plasma mass spectrometer. The results are shown in Table 1. The concentrations of copper, magnesium, calcium, and palladium in the manganese steel and chromium molybdenum steel were measured by subjecting the inner surface of the storage container to XPS analysis in the same manner as in Example 1.
表１に示す結果から分かるように、実施例１～８は、２３℃、３０日間の保管後のニッケル、亜鉛、クロム、モリブデン、及びタングステンの濃度の総和は５００質量ｐｐｂ以下であった。これに対し、比較例１～６は、２３℃、３０日間の保管後のニッケル、亜鉛、クロム、モリブデン、及びタングステンの濃度の総和は１０００質量ｐｐｂ以上であった。この結果から、比較例１～６においては、銅、マグネシウム、カルシウム、及びパラジウムの触媒作用によって、保管容器を形成する金属材料に含有される金属とフッ化リンとが反応して錯体を形成し、金属不純物が生成したと考えられる。 As can be seen from the results shown in Table 1, in Examples 1 to 8, the sum of the concentrations of nickel, zinc, chromium, molybdenum, and tungsten after storage at 23°C for 30 days was 500 ppb by mass or less. In contrast, in Comparative Examples 1 to 6, the sum of the concentrations of nickel, zinc, chromium, molybdenum, and tungsten after storage at 23°C for 30 days was 1000 ppb by mass or more. From these results, it is believed that in Comparative Examples 1 to 6, the catalytic action of copper, magnesium, calcium, and palladium caused the metals contained in the metal material forming the storage container to react with phosphorus fluoride to form complexes, generating metal impurities.
Claims (10)
前記フッ化リンが接触する部分が金属材料で形成されている保管容器内に前記フッ化リンを保管し、
前記金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下であるフッ化リンの保管方法。 A method for storing phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, comprising the steps of:
storing the phosphorus fluoride in a storage container having a portion that comes into contact with the phosphorus fluoride made of a metal material;
A method for storing phosphorus fluoride, wherein the total concentration of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass % or less.
前記フッ化リンが接触する部分が金属材料で形成されており、前記金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下であるフッ化リンの保管容器。 A storage container for storing phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride,
A storage container for phosphorus fluoride, the portion which comes into contact with the phosphorus fluoride being formed of a metal material, and the total concentration of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass % or less.
前記保管容器の前記フッ化リンが接触する部分が金属材料で形成されており、前記金属材料に含有される銅、マグネシウム、カルシウム、及びパラジウムの濃度の総和が０．８質量％以下であるガス充填済み保管容器。 A gas-filled storage container in which phosphorus fluoride, which is at least one of phosphorus trifluoride, phosphorus pentafluoride, and diphosphorus tetrafluoride, is filled in the storage container,
A gas-filled storage container, wherein a portion of the storage container that comes into contact with the phosphorus fluoride is formed of a metal material, and the sum of the concentrations of copper, magnesium, calcium, and palladium contained in the metal material is 0.8 mass% or less.
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| JPS6070165A (en) * | 1983-05-19 | 1985-04-20 | ユニオン・カ−バイド・コ−ポレ−シヨン | High strength steel and gas storing cylinder made therefrom |
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| JP2012154429A (en) * | 2011-01-26 | 2012-08-16 | Central Glass Co Ltd | Method for supplying high-pressure gas |
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