Measurement of a high aspect ratio micro-structured surface by an AFM

This paper presents the measurement of a high aspect ratio micro-structured surface by a precision AFM probe-unit, which consists of an AFM cantilever, a piezoelectric actuator and a linear encoder. A pre-load piezoelectric actuator with a high stiffness is employed to actuate the AFM cantilever over a long stroke of 70μm. A small linear encoder is used for measuring the displacement of the piezoelectric actuator so that AFM probe-unit can be made in a compact size, which is approximately 80×75×150mm. The encoder scale is aligned along the axis of motion of the actuator to avoid the Abbe error. The AFM probe-unit has a resolution of 1nm. Measurement results of micro-structured surface are reported.