The WIS150 provides high speed automatic inspection and particle count of the surface of Silicon
(Si)- and Silicon Carbide (SiC) wafers of size 4”/100 mm and 6”/150 mm. The inspection is made
using a scanned HeNe 10 mW laser spot of wavelength 632,8 nm and detectors consisting of fibre
optics and photo multipliers.
The tool can detect impurities/particles down to a size of 300 nm.

Two sets of detectors are used, one detecting directly reflected light from the wafer surface i.e. “Light
channel detection” while the other detects scattered reflections i.e. “Dark channel detection”.
Original intention with the WIS150 tool was to screen batches of bare wafers for use during
manufacturing. The intended use now is Single Step scans of single wafers preferably observing
relative results. Therefore, none of the two receive tracks are used which are not properly working as
of now.