US 11,920,257 B2
Method of evaluating cleanliness, method of determining cleaning condition, and method of manufacturing silicon wafer
Takashi Muramatsu, Saga (JP); and Hirokazu Kato, Nagasaki (JP)
Assigned to SUMCO CORPORATION, Tokyo (JP)
Filed by SUMCO CORPORATION, Tokyo (JP)
Filed on Aug. 3, 2021, as Appl. No. 17/392,652.
Application 17/392,652 is a division of application No. 16/087,879, granted, now 11,118,285, previously published as PCT/JP2017/007749, filed on Feb. 28, 2017.
Claims priority of application No. 2016-064071 (JP), filed on Mar. 28, 2016.
Prior Publication US 2021/0363660 A1, Nov. 25, 2021
Int. Cl. C04B 35/565 (2006.01); C23C 16/44 (2006.01); C30B 29/06 (2006.01); G01N 27/62 (2021.01); H01J 37/32 (2006.01); H01L 21/02 (2006.01); H01L 21/304 (2006.01); C30B 23/02 (2006.01); C30B 29/36 (2006.01); G01N 27/623 (2021.01); G01N 33/00 (2006.01)
CPC C30B 29/06 (2013.01) [C04B 35/565 (2013.01); C23C 16/4407 (2013.01); G01N 27/62 (2013.01); H01J 37/32862 (2013.01); H01L 21/02529 (2013.01); H01L 21/304 (2013.01); C30B 23/02 (2013.01); C30B 29/36 (2013.01); G01N 27/623 (2021.01); G01N 2033/0095 (2013.01)] 13 Claims
 
1. A method of determining a cleaning condition of a member having a silicon carbide surface, the method comprising:
cleaning the silicon carbide surface under a candidate cleaning condition;
after the cleaning, evaluating a cleanliness of the member having the silicon carbide surface by a method comprising:
bringing the silicon carbide surface into contact with a mixed acid of hydrofluoric acid, hydrochloric acid, and nitric acid;
concentrating the mixed acid brought into contact with the silicon carbide surface by heating to obtain a concentrated liquid;
adding a solution to the concentrated liquid to obtain a sample solution;
performing quantitative analysis of metal components present in the sample solution by Inductively Coupled Plasma-Mass Spectrometry; and
evaluating the cleanliness of the member having the silicon carbide surface on the basis of a quantitative result of the metal components obtained by the quantitative analysis; and
determining that the candidate cleaning condition under which the cleanliness of the member having the silicon carbide surface has been evaluated to be within an allowable level is to be used as the cleaning condition of the member having the silicon carbide surface.