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Method and Apparatus for Measuring Process Parameters of a Plasma Etch Process

  • US 20130016344A1
  • Filed: 07/14/2011
  • Published: 01/17/2013
  • Est. Priority Date: 07/14/2011
  • Status: Abandoned Application
First Claim
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1. A plasma parameter measurement system for deriving at least one parameter from a modulated light component emitted by a plasma, comprising a plasma light detector for detecting plasma light emissions being generated from the plasma, an optical sensor for converting the detected plasma light to a light signal, a signal processor preparing the light signal for analysis and a signal analyzer for determining at least one parameter from the processed extracted modulated signal, wherein the signal processor comprises:

  • a superheterodyne assembly for receiving the light signal and a reference signal at an intermediating frequency and mixing the light signal and the reference signal to produce a superheterodyned signal at a down-converted intermediate frequency;

    an intermediating frequency filter for filtering the superheterodyned signal across one or more bandwidths relevant to the at least one process state parameter; and

    an intermediating frequency digitizer for digitizing the filtered superheterodyned signal at a sample rate.

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