NonContact Imaging and Probing

Overview

MultiProbe’s AFP II Nanoprober is a powerful tool for characterization of nanometer-scale electronic devices. It combines highly accurate SMUs used for the electrical measurements with Atomic Force imaging system which is the only non-destructive guidance available in the nano-world where the typical dimensions are smaller than the light wavelength. The Non-Contact imaging method allows the Nanoprober to meet new challenges of modern microelectronic industry. The typical examples are an operation over high profile samples or imaging of fragile structures such as nano-wiring made of soft metal.

Features

In the Non-Contact mode the probe is being kept at an Angstrom-scale distance over the sample surface close enough that the probe tip is attracted to the surface by van der Waals (polarization) force, but it is never in repulsion which would be a sign of a true contact, as shown below.

The attractive force is very weak and its detection is difficult. To obtain reliable measurements of the weak tip-surface interactions the probe is actually driven to oscillate with its resonant frequency and subtle changes in these vibrations are detected by the sophisticated electronics which provides the feedback to the piezo drive as shown below. When the Non-Contact image of the surface profile is obtained and the DUT is located, the probes are positioned precisely over the DUT sections and the system is switched to the contact mode, i.e. the probes are landed to form a reliable contact required for the electrical characterization.

The unique combination of advanced technologies allowed MultiProbe’s engineers to drive the electrically and mechanically sound tungsten probes in the Non-Contact mode which eliminates need for high resonant-frequency dielectric crystals.