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. 25, 1995
Filed:
Jan. 15, 1993
Applicant:
Inventors:
Julian G Blake, Beverly Farms, MA (US);
Weilin Tu, Natick, MA (US);
Dale K Stone, Haverhill, MA (US);
Scott C Holden, Manchester, MA (US);
Assignee:
Eaton Corporation, Cleveland, OH (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02N / ;
U.S. Cl.
CPC ...
361234 ;
Abstract
A wafer position and clamp sensor. A circuit monitors capacitance between two electrodes within a wafer support. With no wafer on the support, the capacitance falls in one range, with the wafer in place but not clamped, the capacitance falls in a second range and with the wafer held in place by an electrostatic attraction the capacitance falls in a third range. The sensed capacitance is converted to a frequency and then a DC voltage level that can easily be sensed and used to confirm wafer placement and then confirm wafer clamping.