It is an optical, non-destructive method used to characterize thin, transparent or semi-transparent films, particularly their thickness and optical properties.
It analyzes how light is reflected across a broad spectral range (typically ultraviolet, visible, and near infrared) by measuring interference between reflections from the upper and lower surfaces of a thin layer.
These wavelength-dependent spectral oscillations reveal critical information about the film’s physical and optical structure, enabling fast, accurate thickness measurements.
HOW DOES SPECTROSCOPIC REFLECTOMETRY WORK?
The working principle of Spectroscopic Reflectometry can be described in the following steps, which convert reflected light spectra into precise thin-film thickness measurements:
A broadband light source (white light) illuminates the sample, and the reflected spectrum is captured.
Interference occurs between light reflected from the top and bottom interfaces of the thin film, producing characteristic spectral oscillations.
The reflectance spectrum is compared with a simulated model; film thickness is iteratively adjusted in the simulation until the measured and calculated spectra align.
This fitting process yields rapid and precise thickness diagnostics.
APPLICATIONS
Spectroscopic Reflectometry excels in scenarios requiring rapid, non-invasive thin-film analysis, including:
Semiconductor processing: Measuring mask layer thicknesses.
Consumer electronics & optics manufacturing: Verifying coating and thin-film uniformity with speed and precision.
Tooling manufacturing: Fast detection of thin-layer variations in tooling, micro-optics, or display panels, particularly acutely useful in production environments requiring non-destructive testing.
Scientific research: Ideal for multilayer film studies and photonics, especially when a quick, accurate, and contactless method is needed.
