StraDex f is the basic distance-measuring instrument for all SemDex metrology tools. The technology behind is called Spectral Coherence Interferometry (SCI).
StraDex f measures vertical distances down to 1 µm with high accuracy and precision between two different optically transparent materials with wavelength from 830 nm to 1.300 nm.
Such materials can be: air, polymers, photoresists, dioxides and the common materials used in semiconductor processes like Silicon, Silicon Carbide, Sapphire, Gallium Arsenide and others.
The measuring instrument records sixteen thousand measurement points in a second and combined with the movement of the wafer stage it can generate full wafer data maps within one minute.
StraDex f is usually placed above and underneath the wafer to measure distances even of opaque wafers or wafers with backside roughness.
Matching measuring instruments can be placed in addition on top and bottom side of the stage to extend the range of applications to be covered by only one SemDex metrology tool.
Typical metrology applications are: layer thickness, Silicon & wafer thickness, multi-layer thickness, thin coating thickness, total thickness, bow/warp, high-warpage, flatness, TSV & Trench depth as well as RST.