A metrological scanning force microscope

In this paper, the design, construction, and characterization of a metrological scanning force microscope (SFM) for the purposes of dimensional measurement of surface features is discussed. Using this instrument, precision measurements of engineering surfaces can be performed in air with subnanometer resolution. In this design, scanning of the specimen in the x and y planes and surface profiling in z-axis are each monitored directly by capacitance sensors. The present SFM is capable of a resolutions of approximately 0.1 nm over 15 μm range in z-axis and about 1 nm over 50 pm scanning range in x− and y-axes with a repeatability of less than 1 nm. The linearity error was measured to be within the noise level. Specimens ranging from soft polymeric films to polished zerodur are used to illustrate its metrological capability.