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:
Dec. 08, 1987
Filed:
May. 19, 1986
Applicant:
Inventor:
Chorng-Tao Yu, Placentia, CA (US);
Assignee:
Thermco Systems, Inc., Orange, CA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B / ;
U.S. Cl.
CPC ...
219390 ; 219388 ; 219494 ; 219411 ; 118725 ; 118 501 ;
Abstract
There is a substantial heat loss and drop in temperature in a hot-wall diffusion tube when a batch of wafers at room temperature is loaded into the tube. The temperature of the atmosphere in a zone in the tube is quickly recovered by sensing both the temperature of the tube atmosphere and the temperature of a heating element surrounding the zone with thermocouples, mixing the signals of the thermocouples to produce a ratio average signal and then controlling the heat input to the heating elements in response to the ratio average of the sensed temperature.