Mitsui Toatsu Chemicals, Incorporated

Other

Naruyuki Iwanaga

Isao Harada

Toshihiko Nishitsuji

Tosiaki Yamaguti

Yoshihiro Tsuzikawa

Nobuhiko Fujieda

Akio Kikkawa

Hiroyuki Hyakutake

Makoto Aritsuka

Yukihiro Yoda

Nobuhiko Koto

An electrolytic cell for the production of a nitrogen trifluoride gas by a molten salt electrolysis comprises electrodes, partition plates, bottom surface, liquid surface of an elecrolytic bath and lids, at least some of these members being in a particular distance relationship.

Electrolytic cell

An electrolytic cell for the production of a nitrogen trifluoride gas by a molten salt electrolysis comprises electrodes, partition plates, bottom surface, liquid surface of an electrolytic bath and lids, at least some of these members being in a particular distance relationship.

This invention relates to a process for obtaining a high purity nitrogen trifluoride gas which is used as a dry etching agent for semiconductors or a cleaning gas for CVD apparatus, etc., particularly to a process for removing oxygen difluoride. This is a process for purifying a nitrogen trifluoride gas by, after removing hydrogen fluoride from a nitrogen trifluoride crude gas, contacting with at least one aqueous solution containing one selected from the group consisting of sodium thiosulfate, hydrogen iodide and sodium sulfide.

Process for purifying nitrogen trifluoride gas

Method of liquefying and condensing nitrogen trifluoride and a method of

The method for preparing a gaseous metallic floride is here disclosed which comprises reacting a metal or its oxide with a fluorine gas or nitrogen trifluoride gas, the aforesaid method being characterized by comprising the steps of mixing the metal or its oxide with a molding auxiliary comprising a solid metallic fluoride which does not react with fluorine and nitrogen trifluoride; molding the resulting mixture under pressure; and contacting the molded pieces with the fluorine gas or nitrogen trifluoride gas, while the molded pieces are heated.

Method for preparing gaseous metallic fluoride

There is here disclosed a method for removing nitrous oxide (N.sub.2 O), carbon dioxide (CO.sub.2) and dinitrogen difluoride (N.sub.2 F.sub.2) from a nitrogen trifluoride gas. The present invention is directed to a method for purifying a nitrogen trifluoride gas which comprises the steps of thermally treating, at a temperature of 250.degree. to 700.degree. C., a zeolite selected from the group consisting of analcime, clinoptilolite, mordenite, ferrierite, phillipsite, chabazite, erionite and laumotite; forming a packed bed of the treated zeolite; and passing the nitrogen trifluoride gas containing the gaseous impurities at a temperature of -125.degree. to 50.degree. C. through the filler layer.

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Yamaguchi, Japan

Naruyuki Iwanaga