Abstract: To provide a method for reducing oxygen and carbon components in high-purity fluoride such as calcium fluoride and barium fluoride (high-purity fluoride is not limited to calcium fluoride and barium fluoride), or in rare-earth fluoride such as ytterbium fluoride and cerium fluoride used for an optical fiber, a coating material, and so on.

Abstract: A stainless steel with a passive state fluorinated film formed thereon, which is easy to construct and does not produce particles even when it is welded, and a device using the same. The stainless steel does not cause leakage even when said film is formed on a sealing surface of a joint and a valve seat surface. The stainless steel is characterized in that at least a part of the surface coated with a passive state fluorinated film not thicker than 190Å consisting of a metal fluoride as a main component.

Abstract: A method is provided for fixing and eliminating fluorine and phosphorus in waste water wherein the waste water includes a fluorophosphate compound in which hydrochloric acid is added to the waste water including the fluorophosphate compound. The waste water to which hydrochloric acid has been added is heated in order to decompose the fluorophosphate compound into hydrogen fluoride and phosphoric acid, while hydrogen chloride gas located within a treating vessel in which the waste water is contained is introduced into a condenser provided outside of the treating vessel, and then a calcium salt is added to the waste water after decomposition in order to fix and eliminate fluorine and phosphorus.

Abstract: A hydrogen containing material comprises a first compound including hydrogen containing material and fluoride, and a second compound including a metal which becomes highly reactive with hydrogen when the metal becomes a compound including fluorine, and a compound including fluorine. The first compound and the second compound are integrally formed into a one-piece layer on the surface of the hydrogen containing material. The metal which becomes highly reactive with hydrogen when the metal becomes a compound including fluorine is at least one metal selected from a rare earth metal, rare earth alloy, Fe, Al, Mg, Ca, Mn, Zn, Zr, Li, or alloys comprising these elements.

Abstract: A hydrogen containing material comprises a first compound including hydrogen containing material and fluoride, and a second compound including a metal which becomes highly reactive with hydrogen when the metal becomes a compound including fluorine, and a compound including fluorine. The first compound and the second compound are integrally formed into a one-piece layer on the surface of the hydrogen containing material. The metal which becomes highly reactive with hydrogen when the metal becomes a compound including fluorine is at least one metal selected from a rare earth metal, rare earth alloy, Fe, Al, Mg, Ca, Mn, Zn, Zr, Li, or alloys comprising these elements.

Abstract: A method of purifying lithium hexafluorophosphate that allows to purify lithium hexafluorophosphate, useful as lithium secondary cell electrolyte, organic synthesis medium or the like, to an extremely high purity is provided. Lithium hexafluorophosphate containing harmful impurities such as oxyfluoride, lithium fluoride is purified by adding phosphoric chloride. The purification is performed in the presence of phosphoric chloride and hydrogen fluoride of the quantity equal or superior to the equivalent amount for reacting them, and then by converting lithium fluoride lithium hexafluorophosphate with generated phosphor pentafluoride.

Abstract: An etching treatment agent which can etch insulating film with high speeds without damaging the resist pattern, provide realistic throughput when the insulting film etching process in the semiconductor manufacturing process is replaced with the single wafer processing etching treatment method, and prevent roughness on the surface of the semiconductor after etching.

Abstract: To provide a method for purifying tungsten hexafluoride of high purity, capable of producing tungsten hexafluoride of higher purity than that of the related art, readily and at a low cost.

Abstract: In order to provide a method for producing lithium hexafluorophosphate capable of producing lithium hexafluorophosphate of a higher purity than in the related art without the necessity for after-treatment for removal of impurities, a method is characterized by filtering lithium hexafluorophosphate coexisting with a solvent and then carrying out after-filtering drying in a gas atmosphere containing PF5.

Abstract: A method of purifying lithium hexafluorosphate that allows to purify lithium hexafluorophosphate, useful as lithium secondary cell electrolyte, organic synthesis medium or the like, to an extremely high purity is provided. Lithium hexafluorophosphate containing harmful impurities such as oxyfluoride, lithium fluoride is purified by adding phosphoric chloride. The purification is performed in the presence of phosphoric chloride and hydrogen fluoride of the quantity equal or superior to the equivalent amount for reacting them, and then by converting lithium fluoride to lithium hexafluorophosphate with generated phosphor pentafluoride.

Abstract: An industrial material such as metal, ceramics or plastics whose surface has a film passivated by fluoridation and a process of manufacturing the above industrial material. The industrial material comprises a substrate, a nickel alloy film formed on the substrate and containing nickel, semimetal and/or other metal whose fluoride becomes a volatile compound, and a fluorine passivated film formed at least on a surface of the nickel alloy film in such a manner that the fluorine passivated film contains nickel and does not contain said other metal or the semimetal, and satisfies stoichiometric ratio. The process of manufacturing an industrial material comprises the steps of performing grounding treatment of a surface of a substrate, forming a nickel alloy film, on the surface of the substrate, containing nickel, semimetal and/or other metal, and forming a fluorine passivated film on the nickel alloy film.

Abstract: A fine surface treatment for micromachining having an etching speed whose difference is smaller to oxide films each obtained by a different method as well as conditions of forming film or having different concentration of various impurities such as P, B and As in the film, and also having a practical etching speed to each of the films. The surface treatment for micromachining contains 0.1 to 8 weight percent of hydrogen fluoride and not less than 40 weight percent to not more than 47 weight percent of ammonium fluoride. It should be noted that it is preferable the surface treatment agent contains 0.001 to 1 weight percent of surfactant.

Abstract: Hydrofluoric acid has incorporated therein a hydrocarbon nonionic surfactant having an HLB value of 7 to 17. The composition exhibits improved wetting and other properties for use in surface treatment for micro processing.

Abstract: An etching agent and an electronic device manufacturing method using the etching agent. The etching agent contains, in a solution, hydrofluoric acid at a concentration of 0.05 to 0.5 mol/l, and halooxoacid ions, represented by the formula (XO.sub.n).sup.p- (wherein X is a halogen element, n is 3, 4 or 6, p is 1, 2 or 3), at a concentration of at least 0.01 mol/l. An electronic device manufactured using the etching agent requires only a single etching step to etch both conductive layers (such as aluminum) as well as ohmic contact layers (a-Si).

Abstract: A surface treatment agent containing a solution of hydrogen fluoride, ammonium fluoride and water, the solution containing less than 8 weight % of hydrogen fluoride (HF) and less than 15 weight % of ammonium fluoride (NH.sub.4 F).

Abstract: A tungsten film forming apparatus includes a reaction chamber, means for introducing WF.sub.6 into said reaction chamber, and means for introducing H.sub.2 gas into said reaction chamber, wherein at least the portion of at least said reaction chamber is made of the metal material whose surface is covered with the fluorinated paasivation film mainly consisting of the almost stoichiometric metal fluoride. It becomes possible to form a high quality tungsten film at a low substrate temperature by use of said tungsten film forming apparatus.

Abstract: Dry etching apparatus composed of any of metal, silica, ceramic or combination thereof with a processing chamber in which substrates are placed and a diluted anhydrous hydrogen fluoride gas generator, the processing chamber being connected to the diluted anhydrous hydrogen fluoride gas generator through a pipe line of stainless steel or nickel. There is also disclosed a dry-etching method with the dry-etching apparatus, and a diluted anhydrous hydrogen gas generator used in the dry-etching apparatus and dry-etching method.

Abstract: Disclosed is a dry-etching apparatus composed of any of metal, silica, ceramic or combination thereof including a processing chamber in which substrates are placed and a diluted anhydrous hydrogen fluoride gas generator, the processing chamber being connected to the diluted anhydrous hydrogen fluoride gas generator through a pipe line of such metal as stainless steel or nickel. There is also provided according to the invention a dry-etching method with the dry-etching apparatus, a cooled anhydrous hydrogen fluoride gas source and a diluted anhydrous hydrogen gas generator used in the dry-etching apparatus and dry-etching method.

Abstract: A metal material characterized in that a film passivated by fluorination which is mainly composed of a metal fluoride substantially satisfying stoichiometric ratio is formed at least partially on a surface of a metal of the metal material, and an apparatus at least partially composed of the metal material.

Abstract: A surface treating composition for micro processing which comprises a mixture of hydrofluoric acid, ammonium fluoride solution and water, and at least one compound selected from the group of surfactants consisting of aliphatic carboxylic acids, salts of aliphatic carboxylic acids, aliphatic amines and aliphatic alcohols.