Patent · US Active

Interferometric iterative technique with bandwidth and numerical-aperture dependency

US7505863B2 · kind B2 · utility

1Cited by
3References
36Claims
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Key dates

Filing dateJul 13, 2007
Grant dateMar 17, 2009
Priority date—
Expiry dateJul 13, 2027

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG01B9/02083
  • WIPO fieldMeasurement
  • WIPO sectorInstruments

Abstract

An interferometric intensity equation includes parameters that depend on bandwidth and numerical aperture. An error function based on the difference between actual intensities produced by interferometry and the intensities predicted by the equation is minimized iteratively with respect to the parameters. The scan positions (i.e., the step sizes between frames) that minimized the error function are then used to calculate the phase for each pixel, from which the height can also be calculated in conventional manner. As a result, the phase map generated by the procedure is corrected to a degree of precision significantly better than previously possible.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.