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:
Aug. 29, 2006
Filed:
Mar. 30, 2001
Inductive plasma processor having coil with plural windings and method of controlling plasma density
Jian J. Chen, Fremont, CA (US);
Robert G. Veltrop, Eagle, ID (US);
Thomas E. Wicker, Reno, NV (US);
Lam Research Corporation, Fremont, CA (US);
Abstract
An inductive plasma processor includes a multiple winding radio frequency coil having plural electrically parallel, spatially concentric windings (1) having different amounts of RF power supplied to them, and (2) arranged to produce electromagnetic fields having different couplings to different regions of plasma in the chamber to control plasma flux distribution incident on a processed workpiece. The coil is powered by a single radio frequency generator via a single matching network. Input and output ends of each winding are respectively connected to input and output tuning capacitors. In a first embodiment, the location of maximum inductive coupling of the radio frequency to the plasma and the current magnitude in each winding are respectively mainly determined by values of the output and input capacitors. By adjusting all the input and output capacitors simultaneously, the current to a winding can be varied while the current to the other winding can be maintained constant as if these windings were completely de-coupled and independent. Therefore, the capacitors can control the plasma density in different radial and azimuthal regions. In another embodiment, a relatively low frequency drives the coil whereby each winding has a relatively short electrical length, causing substantially small standing wave current and voltage variations. The output capacitor for each winding adjusts current magnitude, to eliminate the need for the input capacitors and reduce operational complexity.