US 12,437,978 B2
Cleaning method of film layer in the plasma processing apparatus
Kazuhiro Ueda, Tokyo (JP); and Kazuyuki Ikenaga, Tokyo (JP)
Assigned to Hitachi High-Tech Corporation, Tokyo (JP)
Appl. No. 17/802,639
Filed by Hitachi High-Tech Corporation, Tokyo (JP)
PCT Filed Aug. 23, 2021, PCT No. PCT/JP2021/030850
§ 371(c)(1), (2) Date Aug. 26, 2022,
PCT Pub. No. WO2023/026331, PCT Pub. Date Mar. 2, 2023.
Prior Publication US 2024/0203708 A1, Jun. 20, 2024
Int. Cl. B08B 3/12 (2006.01); H01J 37/32 (2006.01)
CPC H01J 37/32862 (2013.01) [B08B 3/12 (2013.01); H01J 37/32495 (2013.01); H01J 2237/3151 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A cleaning method of a protective film for a plasma processing apparatus, the protective film containing yttrium oxide or yttrium fluoride oxide or yttrium aluminum garnet and being formed on a surface of a base material disposed inside a processing chamber of the plasma processing apparatus for processing a wafer to be processed placed in the processing chamber disposed inside a vacuum chamber by using plasma formed in the processing chamber, the cleaning method comprising:
a step of cleaning performed by immersing the base material in a dilute nitric acid solution and performing ultrasonic irradiation on the protective film for the plasma processing apparatus,
wherein the cleaning is stopped after an 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.