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. 29, 1992
Filed:
Dec. 23, 1991
Steven D Hurwitt, Park Ridge, NJ (US);
Arnold J Aronson, Pomona, NY (US);
Charles Van Nutt, Monroe, NY (US);
Materials Research Corporation, Orangeburg, NY (US);
Abstract
A plasma confining magnetic field is generated over the sputtering region of a sputtering target with a critical field line which determines the shape of the plasma. The critical field line is progressively flattened over the course of the life of the target as the target erodes. Preferably, the magnet is configured with poles spaced around the portion of the target below the sputtering region to provide a magnetic field that flattens as its strength decreases. A regulated power supply maintains a regulated power level that is increased as the target erodes to maintain a constant deposition rate. The voltage delivered by the power supply is maintained at or above a constant level by progressively decreasing the current to an electromagnet to progressively reduce the field strength and flatten the field. As a result of the invention, the erosion groove of the target is broadened and the number of wafers coated by the target during its life is increased.