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Assessment and optimization for metrology instrument including uncertainty of total measurement uncertainty

  • US 7,286,247 B2
  • Filed: 02/22/2005
  • Issued: 10/23/2007
  • Est. Priority Date: 12/20/2002
  • Status: Expired due to Fees
First Claim
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1. A method for assessing a measurement system under test (MSUT), the method comprising the steps of:

  • (a) providing a substrate having a plurality of structures;

    (b) measuring a dimension of the plurality of structures using a reference measurement system (RMS) to generate a first data set, and calculating an RMS uncertainty (URMS) from the first data set, where the RMS uncertainty (URMS) is defined as one of(i) an RMS precision;

    (ii) an independently determined RMS total measurement uncertainty (TMURMS); and

    (iii) VURMS=VST+VAG, wherein VURMS is URMS expressed as a variance, VST is a short term precision variance, and VAG is an across grating variance;

    (c) measuring the dimension of the plurality of structures using the MSUT to generate a second data set, and calculating a precision of the MSUT from the second data set;

    (d) conducting a linear regression analysis of the first and second data sets to determine a corrected precision of the MSUT and a net residual error;

    (e) determining a total measurement uncertainty (TMU) for the MSUT by removing the RMS uncertainty (URMS) from the net residual error; and

    (f) outputting the TMU to a system capable of optimizing the MSUT.

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