The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 27, 2023
Filed:
Jan. 22, 2021
Kokusai Electric Corporation, Tokyo, JP;
Shin-etsu Quartz Products Co., Ltd., Tokyo, JP;
Shinya Morita, Toyama, JP;
Toru Nakada, Toyama, JP;
Hiroyuki Kimura, Tokyo, JP;
Toru Segawa, Fukushima, JP;
KOKUSAI ELECTRIC CORPORATION, Tokyo, JP;
SHIN-ETSU QUARTZ PRODUCTS CO., LTD., Tokyo, JP;
Abstract
There is provided a technique that includes a first annealing step of annealing the reaction tube; a first cleaning step of cleaning an inner surface of the reaction tube, after the first annealing step, with a liquid including a fluorine compound having a first concentration; a first rinsing step of washing away the fluorine compound used in the first cleaning step with pure water; a second annealing step of annealing the reaction tube; a second cleaning step of cleaning the inner surface of the reaction tube, after the second annealing step, with a liquid including a fluorine compound having a second concentration higher than the first concentration; and a second rinsing step of washing away the fluorine compound used in the second cleaning step with pure water.