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:
Aug. 17, 2021
Filed:
Jun. 19, 2018
Applicant:
Sumco Corporation, Tokyo, JP;
Inventors:
Toshiaki Ono, Tokyo, JP;
Shigeru Umeno, Tokyo, JP;
Assignee:
SUMCO CORPORATION, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C30B 29/06 (2006.01); H01L 21/322 (2006.01); C30B 30/04 (2006.01); C30B 33/02 (2006.01);
U.S. Cl.
CPC ...
H01L 21/3225 (2013.01); C30B 29/06 (2013.01); C30B 30/04 (2013.01); C30B 33/02 (2013.01);
Abstract
A silicon wafer having a BMD density of 5×10/cmor more and 2.5×10/cmor less in a region of 80 μm to 285 μm from the wafer surface when the silicon wafer is heat-treated at a temperature X (° C., 700° C.≤X≤1000° C.) for a time Y (min) and then subjected to an infrared tomography method in which the laser power is set to 50 mW and the exposure time of a detector is set to 50 msec. The time Y and the temperature X satisfy Y=7.88×10×X.