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:
Mar. 23, 2021
Filed:
Mar. 06, 2019
Applicant:
Kabushiki Kaisha Toshiba, Minato-ku, JP;
Inventors:
Assignee:
KABUSHIKI KAISHA TOSHIBA, Minato-ku, JP;
Primary Examiner:
Int. Cl.
CPC ...
H01L 21/311 (2006.01); H01L 21/02 (2006.01); H01L 21/67 (2006.01); H01L 21/306 (2006.01); C09K 13/08 (2006.01);
U.S. Cl.
CPC ...
H01L 21/31111 (2013.01); C09K 13/08 (2013.01); H01L 21/02164 (2013.01); H01L 21/30604 (2013.01); H01L 21/67075 (2013.01); H01L 21/67086 (2013.01);
Abstract
According to one embodiment, an etching solution used for etching of silicon nitride is provided. The etching solution includes phosphoric acid, an acid, silicic acid compound, and water. The phosphoric acid has a first acid dissociation exponent pK. The acid has an acid dissociation exponent smaller than the first acid dissociation exponent pK. A mass ratio M/Mof mass Mof the phosphoric acid to mass Mof the acid having the acid dissociation exponent smaller than the first acid dissociation exponent pKis within a range of 0.82 or more and 725 or less.