Computerized interferometric measurement of surface microstructure

Nearly all modern high-quality measuring instruments now use micro computers for the collection and analysis of data. This paper describes a computerized interferometric microscope system for the measurement of surface microstructure. For the instrument described in this paper the surface microstructure can be measured at data array sizes as large as 739 X 484 points for measurement fields ranging from 30 X 25 microns to 8.2 X 6.1 mm. A repeatability of the surface height measurements of less than 0.1 nm can be obtained for smooth surfaces. Surfaces having height variances as large as 500 microns can be measured to within an accuracy of a few nanometers.