Date Announced: 09 Oct 2020
Our partners, Specim have recently published an article on thin film inspection using the FX17. The FX17 is a small footprint hyperspectral camera built around an InGaAs detector. It operates in the NIR spectral range (900-1700 nm), F/1.7 optics enable excellent light throughput, high sensitivity, short integration times and high signal-to-noise ratio.
Thickness is a crucial quality parameter in thin films and coatings. The thickness and homogeneity strongly affect the film’s functionality and they need accurate monitoring. X-ray techniques and optical spectroscopy are in wide use for this purpose both in tabletop and in-line inspection systems.
However, only point sensors are currently employed and, for in-line applications, are typically mounted on a scanning transversal stage, leading to a zigzag inspection pattern. The film under inspection is thus only partly monitored.
A line-scan (push-broom) hyperspectral camera can overcome this limitation and inspect the full film or coating. In each line capture, spectroscopic data over the full film width is produced at high spatial resolution.
To demonstrate hyperspectral imaging in this application, Specim measured four polymer thin film samples with a spectral camera operating in the region of 935 – 1700 nm (Specim FX17). The sample films’ nominal thicknesses were 17, 20 (two films), and 23 um. Specular geometry was used, and interferences were scrutinized. Depending on the spectral position and distance between constructive interferences, the thickness can be deduced:
Read the full article here