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. 22, 1994
Filed:
Jun. 25, 1993
Applicant:
Inventor:
Tetu Ohsawa, Sagamihara, JP;
Assignees:
Tokyo Electron Limited, Tokyo, JP;
Tokyo Electron Tohoku Limited, Esashi, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
437247 ; 437949 ; 148D / ;
Abstract
A wafer boat on which semiconductor wafers are placed is inserted into a process tube, and a process gas is supplied into the process tube to perform heat treating. In this case, prior to the heat treating, the process tube is evacuated to have a pressure lower than a pressure in the heat treating while a temperature in the process tube is kept to be higher than a temperature in the heat treating. After the heat treating is performed, the process tube is purged with an N.sub.2 gas.