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:
Oct. 07, 2025
Filed:
Aug. 23, 2021
Hitachi High-tech Corporation, Tokyo, JP;
Kazuhiro Ueda, Tokyo, JP;
Kazuyuki Ikenaga, Tokyo, JP;
Hitachi High-Tech Corporation, Tokyo, JP;
Abstract
A cleaning method of a protective film for a plasma processing apparatus, the protective film being formed on a surface of a base material disposed inside a processing chamber of the plasma processing apparatus for processing a wafer using plasma, and containing a material having resistance to the plasma, and the cleaning method includes: (a) a step of preparing the base material including the film containing yttrium on the surface; and (b) a step of cleaning performed by immersing the base material in a dilute nitric acid solution and performing ultrasonic irradiation on the film, in which in the step (b), an elution rate of yttrium is detected in the cleaning, and the cleaning is stopped after the elution rate of yttrium after a start of the ultrasonic irradiation sequentially goes through a first decrease, a first increase, and a second decrease and before a second increase occurs.