DEVELOPMENT OF AN ATOMIC-FORCE MICROSCOPE USING A CRITICAL ANGULAR SENSOR

A new type of atomic force microscope (AFM) is described. in this new AFM an optical angular sensor is used for detecting the deflected angle of a cantilever instead of the deflected displacement, and the cantilever is driven directly by a piezoactuator in the z-direction in accordance with the profile of a surface. The developed AFM has advantages that it is sensitive, compact in size, and well suited for the roughness measurement of big workpieces with high scanning speed and large scanning areas. It has a vertical resolution of better than 1 nm and has been successfully used to obtain several accurate images of machined surfaces. The results by the AFM are compared with those by a SEM and a STM, and the importance of comparisons among the results by different measuring principles has been confirmed.