Development of a Traceable Atomic Force Microscope

In order to realize the traceability of Atomic Force Microscopes (AFM), we have designed a Traceable Atomic Force Microscope (TAFM) to calibrate the pitch standards. The TAFM consists of an atomic force microscope, a 3-axis active compensation flexure stage, two differential plane mirror laser interferometers, a L-shape mirror, a vibration isolator, and a Super-INVAR metrology frame. A test specimen was laid onto the same plane of the laser interferometers to eliminate the Abbe-offset. The x,y movements were controlled by a flexure stage and the displacements were recorded by laser interferometers while the z movement was controlled by the AFM cantilever and the displacement was recorded by a capacitive sensor. A water circulatory was used to maintain the TAFM at 20 degreesC. Measuring results of a standard pitch sample show that this TAFM can be used for measuring standards. The standard uncertainty of pitch measurement with a nominal value of 292 nm was 1.2 nm.