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

• Current Assignee: Sumco Corporation
• Original Assignee: Sumco Corporation
• Inventors: Muramatsu, Takashi, Kato, Hirokazu
• Primary Examiner(s): Qi, Hua
• Application Number:
  US16/087,879
• Publication Number:
  US 20190106810A1
• Time in Patent Office: 1,659 Days
• CPC Class Codes: C04B 35/565 based on silicon carbide
• CPC Class Codes: C23C 16/4407 Cleaning of reactor or reactor parts by using wet or mechanical methods
• CPC Class Codes: C30B 23/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/06 Silicon
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: G01N 1/32 Polishing; Etching
• CPC Class Codes: G01N 2033/0095 Semiconductive materials
• CPC Class Codes: G01N 21/73 using plasma burners or torches
• CPC Class Codes: G01N 27/62 by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
• CPC Class Codes: G01N 27/623 combined with mass spectrometry
• CPC Class Codes: H01J 37/32862 In situ cleaning of vessels and/or internal parts
• CPC Class Codes: H01L 21/02529 Silicon carbide
• CPC Class Codes: H01L 21/304 Mechanical treatment, e.g. grinding, polishing, cutting H01L21/30625 takes precedence

Abstract

Provided is a method of evaluating cleanliness of a member having a silicon carbide surface, the method including 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; subjecting a sample solution obtained by diluting a concentrated liquid obtained by the concentration to quantitative analysis of metal components by Inductively Coupled Plasma-Mass Spectrometry; and evaluating cleanliness of the member having a silicon carbide surface on the basis of a quantitative result of metal components obtained by the quantitative analysis.

Claims

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.

2. The method of evaluating cleanliness according to claim 1, wherein, in the mixed acid, a concentration of hydrofluoric acid ranges from 5 to 15 mass %, a concentration of hydrochloric acid ranges from 5 to 15 mass %, and a concentration of nitric acid ranges from 5 to 15 mass %.

3. The method of evaluating cleanliness according to claim 2, wherein the member having the silicon carbide surface is a member for manufacturing a silicon wafer.

4. The method of evaluating cleanliness according to claim 3, wherein the member for manufacturing the silicon wafer is a susceptor.

5. The method of evaluating cleanliness according to claim 1, wherein the solution added to the concentrated liquid is an aqueous solution of hydrofluoric acid and hydrogen peroxide.

6. The method of evaluating cleanliness according to claim 5, wherein the member having the silicon carbide surface is a member for manufacturing a silicon wafer.

7. The method of evaluating cleanliness according to claim 6, wherein the member for manufacturing the silicon wafer is a susceptor.

8. The method of evaluating cleanliness according to claim 1, wherein the member having the silicon carbide surface is a member for manufacturing a silicon wafer.

9. The method of evaluating cleanliness according to claim 8, wherein the member for manufacturing the silicon wafer is a susceptor.