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RF impedance matching network

  • US 9,697,991 B2
  • Filed: 07/01/2015
  • Issued: 07/04/2017
  • Est. Priority Date: 01/10/2014
  • Status: Active Grant
First Claim
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1. A radio frequency (RF) impedance matching network comprising:

  • an RF input configured to receive an RF signal from an RF source;

    an RF output configured to operably couple to a plasma chamber;

    at least one electronically variable capacitor (EVC) having a variable capacitance;

    a control circuit configured to;

    instruct the at least one EVC to alter the variable capacitance, the alteration of the variable capacitance causing the matching network to achieve a preliminary match state, the preliminary match state having an associated first reflection parameter value at an RF source output; and

    upon the achievement of the preliminary match state, instruct the RF source to alter a variable RF source frequency, the alteration of the variable RF source frequency causing achievement of a final match state, the final match state having an associated second reflection parameter value at the RF source output;

    wherein the second reflection parameter value is less than the first reflection parameter value; and

    wherein, when a subsequent reflection parameter value at the RF source output exceeds a predetermined value, the control circuit again instructs the alteration of the variable capacitance and the variable RF source frequency.

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