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:
Oct. 19, 1999
Filed:
Apr. 10, 1998
Grant Kenji Larsen, Gloucester, MA (US);
Varian Semiconductor Equipment Associats, Inc., Gloucester, MA (US);
Abstract
Apparatus for electrostatic clamping of a workpiece, such as a semiconductor wafer, includes a platen assembly defining an electrically-insulating clamping surface for receiving the workpiece. The platen assembly includes electrodes underlying and electrically isolated from the clamping surface and a dielectric layer between the electrodes and the clamping surface. The dielectric layer may have a periphery which is beveled to define a blunt first edge that forms a boundary of the clamping surface and a second edge that is spaced from the workpiece. A thin, low friction, high hardness dielectric coating may be provided over the dielectric layer. The electrodes may be fabricated of niobium. The disclosed electrostatic wafer clamp provides excellent performance with respect to particulate contamination of the workpiece.