Method and system for characterizing a plasma
AssigneeTokyo Electron Limited
InventorsRonald Victor BRAVENEC, Jianping Zhao
Life of this patent
Estimating the term…
Abstract
Disclosed are a method and system for measuring the electron energy distribution function (EEDF) in a plasma which has a pronounced drifting Maxwellian component of the EEDF. The method comprises fitting an acquired unfiltered electron current vs. bias voltage curve to a functional form which assumes an EEDF comprising at least one stationary Maxwellian component and at least one drifting Maxwellian component. The method and system allow more accurate characterization of plasmas with electron components with pronounced drift, such as plasmas in microwave surface wave plasma (SWP) sources.
Claims20
A method of measuring an electron energy distribution function (EEDF) of a plasma, comprising:
- generating the plasma in a plasma source;
- positioning a probe tip within the plasma, at a first location;
- sweeping an applied bias voltage of the probe tip;
- measuring a first unfiltered current vs. bias voltage curve at the probe tip;
- determining a first unfiltered electron current vs. bias voltage curve from the measured first unfiltered current vs. bias voltage curve;
- and
- determining a first electron energy distribution function of the plasma from a curve fit to the first unfiltered electron current vs. bias voltage curve,
- wherein the first electron energy distribution function comprises one drifting Maxwellian term.
A method of measuring an electron energy distribution function (EEDF) of a plasma, comprising:
- generating the plasma in a plasma source;
- positioning a probe tip within the plasma;
- sweeping an applied bias voltage of the probe tip;
- measuring an unfiltered current vs. bias voltage curve at the probe tip;
- determining an unfiltered electron current vs. bias voltage curve from the measured unfiltered current vs. bias voltage curve;
- and
- determining an electron energy distribution function of the plasma from a curve fit to the unfiltered electron current vs. bias voltage curve,
- wherein the electron energy distribution function comprises one drifting Maxwellian term.
A system for measuring an electron energy distribution function (EEDF) of a plasma, comprising:
- a probe, comprising an elongated probe body and a probe tip;
- a sweeping voltage source in electrical communication with the probe tip, for applying a bias voltage to the probe tip;
- a data acquisition device in electrical communication with the probe tip, for measuring the current flowing from the plasma to the probe tip, in response to the bias voltage;
- and
- a data processing device, in communication with the data acquisition device,
- wherein the data processing device is configured to determine an unfiltered electron current vs. bias voltage curve from the measured unfiltered current vs. bias voltage curve, and further to determine the electron energy distribution function of the plasma by performing a curve fit to the unfiltered electron current vs. bias voltage curve,
- wherein the electron energy distribution function comprises one drifting Maxwellian term.
Dependencies are inferred from the claim text.