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:
Jul. 11, 2000
Filed:
Aug. 28, 1998
Applicant:
Inventors:
Yoshimitsu Ishibashi, Ayase, JP;
Katsuaki Usui, Fujisawa, JP;
Assignee:
Ebara Corporation, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02P / ;
U.S. Cl.
CPC ...
388800 ; 318-3 ;
Abstract
A vacuum pump for use in an evacuating system for a semiconductor fabrication apparatus is operated at a steady rotational speed to evacuate the semiconductor fabrication apparatus. Then, in response to a signal indicative of an operating state of the semiconductor fabrication apparatus which does not need to be evacuated, the rotational speed of the vacuum pump is reduced to an idling rotational speed, thereby to lower electric energy consumption by the vacuum pump.