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. 02, 2002
Filed:
Apr. 04, 2000
John H. Keller, Newburgh, NY (US);
K2 Keller Consulting, Newburgh, NY (US);
Abstract
Uniformity of plasma density is enhanced at high plasma density and with reduced gas cracking and/or without electron charging of a workpiece by limiting coupling of voltages to the plasma and returning a majority of RF current to elements of an antenna driven with different phases of a VHF/UHF signal and/or providing a magnetic filter which separates a hot plasma region from a cold plasma region along a side of the chamber and further provides a preferential drift path between the hot and cold plasma regions. The magnetic field structure of the magnetic filter is preferably closed at one end or fully closed to surround the plasma. Additional magnetic elements limit the transverse field at the surface of a workpiece to less than 10 Gauss. Either or both of the antenna and the magnetic filter can be retrofitted to existing plasma reactor vessels and improve the performance and throughput thereof.