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Systems and methods for calibrating a switched mode ion energy distribution system

  • US 9,210,790 B2
  • Filed: 08/28/2012
  • Issued: 12/08/2015
  • Est. Priority Date: 08/28/2012
  • Status: Active Grant
First Claim
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1. A method of calibrating a bias supply configured to generate a potential on a top surface of a substrate during plasma processing of the substrate, the method comprising:

  • emulating a plasma sheath capacitance with a variable capacitance circuit of a plasma load emulator without generating any plasma;

    emulating plasma ion current with a variable current source without generating any plasma;

    receiving a modified periodic voltage function from the bias supply comprising pulses and a portion between the pulses;

    receiving an expected ion energy;

    receiving an expected ion current;

    delivering the modified periodic voltage function to a plasma load emulator;

    measuring a voltage across the variable capacitance circuit of the plasma load emulator;

    applying a known current from the variable current source of the plasma load emulator to the variable capacitance circuit to emulate the ion current;

    comparing the voltage across the variable capacitance circuit of the plasma load emulator to the expected ion energy and determining an ion energy error from this comparing;

    comparing the known current from the variable current source of the plasma load emulator to the expected ion current and determining an ion current error from this comparing;

    generating calibration data with the ion energy error and the ion current error; and

    storing the calibration data in a calibration data store in the bias supply, wherein the calibration data is subsequently utilized to more accurately effectuate ion energy in an actual plasma during the plasma processing of the substrate.

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