Page 14 - smartWLI technology
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extended phase shift interferometry
µm
20
15
10
5
0
-5
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 m
VSI (vertical scanning interferometry)
algorithms are looking for the max. interference pattern in the image stack
the z – resolution is limited to app. 1 nm
PSI (phase shift interferometry)
the phase shift analyses increase the z resolution
the z – resolution is improved to app. 0.1 nm but limited to steps up to app. 250 nm
EPSI (extended phase shift interferometry)
the extended phase shift interferometry combines both algorithms
the improved z – resolution can be used on objects with heights of several µm
Ra = 25 nm