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Method and apparatus for measurements of patterned structures

  • US 20020128784A1
  • Filed: 11/13/2001
  • Published: 09/12/2002
  • Est. Priority Date: 03/18/1998
  • Status: Active Grant
First Claim
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1. A method for measuring at least one desired parameter of a patterned structure, which represents a grid having at least one cycle formed of at least two metal-containing regions spaced by substantially transparent regions with respect to incident light thereby defining a waveguide, the structure having a plurality of features defined by a certain process of its manufacturing, the method comprising the steps of:

  • a) providing an optical model, which is based on at least some of said features of the structure, on relation between a wavelength range of the incident light to be used for measurements and a space size between the two metal-containing regions in the grid cycle, and a skin depth of said metal, and is capable of determining theoretical data representative of photometric intensities of light components of different wavelengths specularly reflected from the structure and of calculating said at least one desired parameter of the structure;

    b) locating a measurement area for applying thereto spectrophotometric measurements, wherein said measurement area is a grid cycles containing area;

    c) applying the spectrophotometic measurements to said measurement area by illuminating it with incident light of a preset substantially wide wavelength range, detecting light component substantially specularly reflected from the measurement area, and obtaining measured data representative of photometric intensities of each wavelength within said wavelength range;

    d) analyzing the measured data and the theoretical data and optimizing said optical model until said theoretical data satisfies a predetermined condition; and

    e) upon detecting that the predetermined condition is satisfied, calculating said at least one parameter of the structure.

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