Nanometer-Scale Layer Removal of Aluminum and Polystyrene Surfaces by Ultrasonic Scratching

An atomic force microscope combined with a quartz crystal resonator have been employed for nanometer-scale layer removal by ultrasonic scratching. The atomic force microscope has a very sharp diamond tip mounted on the end of a cantilever for surface scratching. Sample thin films are deposited on the surface of an AT-cut quartz crystal resonator which is able to oscillate the surface laterally at its resonance frequency of 5 MHz. Surfaces of aluminum and polystyrene were scratched withx-yscanning of 3×3 µ m2with a micronewton loading force, and the topographies of the scratched areas were observed. Scratching with surface oscillation can result in deep carving of the surface in spite of a low loading force which is not sufficient for removal of the surface without oscillation. The hollow bottom of the polystyrene surface which was scratched with surface oscillation was obviously flat in comparison with the surface scratched without oscillation.