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Methods and apparatus for applying periodic voltage using direct current

  • US 9,039,871 B2
  • Filed: 05/10/2011
  • Issued: 05/26/2015
  • Est. Priority Date: 11/16/2007
  • Status: Active Grant
First Claim
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1. A method for applying pulsed DC power to a plasma processing chamber, the method comprising:

  • applying a negative potential to a cathode during a sputtering portion of a particular cycle of the pulsed DC power for a first time duration, the negative potential having a magnitude, whereby the application of the negative potential effectuates sputtering;

    applying, during a reverse-potential portion of the particular cycle, a positive potential to the cathode for a second time duration that is less than the first time duration, a magnitude of the positive potential is the same as the magnitude of the negative potential; and

    applying, during a recovery portion of the particular cycle, a recovery potential for a third time duration that has a magnitude that is less than the magnitude of the negative potential and is less than the magnitude of the positive potential;

    whereinthe sum of the second and third time durations is less than the first time duration;

    the sum of the second and third time durations is less than ten percent of the particular cycle; and

    the second duration is less than ten percent of the particular cycle and at least one microsecond.

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