Method of evaluating cleanliness, method of determining cleaning condition, and method of manufacturing silicon wafer

  • US 11,118,285 B2
  • Filed: 02/28/2017
  • Issued: 09/14/2021
  • Est. Priority Date: 03/28/2016
  • Status: Active Grant
First Claim
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1. A method of evaluating cleanliness of a member having a silicon carbide surface, which comprises:

  • 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 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.

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