Chromatic sensor-based- profilometer for the focusing mirror in the Scanning Helium Microscope

The paper is aimed at describing measurement methodology for characterizing quality of a silicon wafer applied as a focusing element in the Scanning Helium Microscope and continues the struggle against phenomena decreasing accuracy. The focusing mirror being the heart of the system and the decisive factor, which defines the resolution of the microscope, indicates the importance of testing methods. The systems made specially for this purpose provide the ability to create maps of the surface shape, thickness and surface roughness of the wafers. The paper shows many multidisciplinary issues associated with the measurements procedures and concludes with discussion on accuracy limits.