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US 11,237,120 B2Granted
Expediting spectral measurement in semiconductor device fabrication
AssigneeKLA-Tencor Corporation
InventorsVincent Immer, Tal Marciano, Etay Lavert
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Abstract
A device and method for expediting spectral measurement in metrological activities during semiconductor device fabrication through interferometric spectroscopy of white light illumination during calibration, overlay, and recipe creation.
Claims14
An interferometric-spectroscopy metrology tool comprising:
- an interferometric microscope configured to create an interferogram from white light illumination, the microscope having:
- a horizontally conveyable reference mirror or a conveyable beam splitter cube,
- a focal lens fixed at a focal distance from a processed wafer;
- a two-dimensional, pixel-array detector configured to capture multiple, pixel-specific interferograms in accordance with a changing optical path distance of light beams derived from the white light illumination;
- and
- a computer configured to apply a Fourier transform on each of the pixel-specific interferograms so as to generate a pixel-specific frequency spectrum associated with each corresponding area of the processed wafer, wherein the computer is further configured to determine refractive index from the frequency spectrum.
3 more elements
A method of expediting acquisition of hyperspectral data in semiconductor
- device fabrication metrology, the method comprising:
- splitting white light illumination with an interferometric microscope into two light beams;
- changing an optical path distance traveled by the lights beams while maintaining focus on the processed wafer;
- capturing a pixel-specific interferograms on a two-dimensional, pixel-array detector in accordance with the changing optical path distance traveled by the light beams;
- applying a Fourier transformation to each a pixel-specific interferogram so as to generate a pixel-specific frequency spectrum of the processed wafer;
- and
- assigning pixel grey levels proportional to a chosen pixel, centroid frequency and bandwidth.
4 more elements
Dependencies are inferred from the claim text.