The F3-sX family measures semiconductor and dielectric layers up to 3 mm thick. Such thick layers tend to be rougher and less uniform than thinner layers, which the F3-sX counters with a 10-µm-diameter measurement spot. With it the F3-sX family easily measures materials that are impossible to measure with other instruments. Measurement rates of up to 1 kHz also make the F3-sX a top choice for many in-line applications (e.g. roll-to-roll processes).

The F3-sX family uses near-infrared (NIR) light to measure layer thickness - even many layers that are opaque to the eye (such as semiconductors). The 980 nm wavelength version, the F3-s980, is designed for cost-sensitive applications. The F3-s1310 is optimized for measuring heavy-doped-silicon, while the F3-s1550 is intended for the thickest of layers.

Accessories include automated mapping stages, a video camera with measurement-spot visualization, and visible-wavelength options that extend thickness measurement capabilities down to 15 nm.