Abstract
We demonstrate a broadband implementation of coherent Fourier scatterometry (CFS) using a supercontinuum source. Spectral information can be resolved by splitting the incident field into two pulses with a variable delay and interfering them at the detector after interaction with the sample, bearing similarities with Fourier-transform spectroscopy. By varying the time delay between the pulses, a collection of diffraction patterns is captured in the Fourier plane, thereby obtaining an interferogram for every camera pixel. Spectrally resolved diffraction patterns can then be retrieved with a per-pixel Fourier transform as a function of the delay. We show the physical principle that motivates the two-pulse approach, the experimental realization, and results for a silicon line grating. The presented implementation using a supercontinuum source offers a cost-effective way to acquire multi-wavelength CFS data over a wide wavelength range, with the potential to improve reconstruction robustness and sensitivity in applications such as dimensional metrology.
Original language | English |
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Article number | 013702 |
Pages (from-to) | 013702-1-013702-10 |
Number of pages | 10 |
Journal | Review of Scientific Instruments |
Volume | 96 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2025 |
Keywords
- Scatterometry
- Gratings
- Metrology
- Nanostructures
- Optical scatterometry
- Interferometry
- Fourier transform spectroscopy