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Evaluation of etching processes in semiconductors

  • US 6,472,238 B1
  • Filed: 02/09/2000
  • Issued: 10/29/2002
  • Est. Priority Date: 02/09/2000
  • Status: Expired due to Term
First Claim
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1. A method of evaluating a semiconductor wafer including a substrate and at least one layer formed there, said wafer having been subjected to an etching process, said method comprising the steps of:

  • measuring the wafer by obtaining optical measurements at a plurality of wavelengths, said measurements including reflectivity measurements;

    comparing the average reflectivity across one wavelength range with the average reflectivity across another wavelength range to determine if the wafer has been over or under etched; and

    evaluating the characteristics of wafer based on the measurements, said characteristics including at least one of layer thickness, index of refraction and extinction coefficient, with the evaluation being premised upon the determination of whether the wafer has been over or under etched.

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