Development of the AFM tweezers system

A new class of atomic force microscope (AFM) which provides tweezers function in addition to atomic force observation is described. In order to integrate a function of nano-manipulation with AFM, a new micromachined tweezers is developed, named AFM tweezers. This device has two wedged probes at the end of cantilevers; one is used for AFM observation (imaging probe) and the other (movable probe) for grasping a target sample which is just observed by the imaging probe. The mechanical resonant frequency of the imaging probe is higher than that of the movable probe. The integration of both AFM observation and manipulation realizes a successful manipulation of a sample which is by far smaller than the optical microscope´s resolution. The movable probe is actuated by an integrated thermal expansion actuator which is operated by a voltage source of up to 30 V and responded up to 10 Hz. The wedge shaped probes were fabricated by combination of anisotropic etching of silicon using KOH solution and local oxidation of silicon (LOCOS) technique. A software for operation of the AFM tweezers is designed, which is installed to SPA400 AFM system (SII Nanotechnology Inc.), the manipulation sequence including approach, grasp, and pick-up is automated.