Patent Number: 6,309,978

Title: Beat frequency modulation for plasma generation

Abstract: An apparatus and method for providing a modulated-bias plasma aredescribed. In particular, a radio frequency (RF) source or collectorincludes one or more sources to provide differing driving frequencies orbias frequencies, respectively. These frequencies, over time, interferewith one another to produce beating at one or more controllable,infinitely variable beat frequencies. As a beat frequency hassignificantly fewer cycles per second than a driving or bias frequency, amodulated-bias plasma may be provided without turning power on and off asin conventional "pulsed" plasma systems. Beat frequencies facilitatemodulation of the driving or bias frequencies, which may lie within arelatively narrow frequency band. Also, the use of a plurality of drivingor bias frequencies facilitates use of more conventional RF sources orcollectors owing to lower power requirements at each frequency. Inaccordance therewith, the apparatus and method described may be employedfor plasma etching and/or plasma enhanced vapor deposition.

Inventors: Donohoe; Kevin G. (Boise, ID), Hagedorn; Marvin F. (Meridian, ID)


International Classification:

Expiration Date: 10/32013