A New Atomic Force Microscopy (AFM) Probe for Direct Measurement of Viscoelastic Forces

Byungki Kim, Mechanical Engineering

Knowing interaction forces between nanostructures and their substrates is important in nanomanufacturing, such as template-directed-assembly. A new mechanical membrane-based AFM (atomic force microscopy) probe is proposed for measuring interaction forces between its tip and a substrate together with the topography of the substrate. The electrically conductive membrane type probe structure has electrodes underneath to apply voltage between the electrode and membrane to provide the tapping mode. Since the structure with broad bandwidth no longer depends on its natural frequency to provide the tapping mode, it is expected to achieve noticeable transient response by proper stiffness of the probe while providing the tapping mode by the electrostatic force. The motion of the tip is detected by an integrated deformable grating, which diffracts the laser beam to the photo detector. While the membrane is deformed, the diffracted beam changes its intensity. The displacement of the tip can thus be monitored by measuring the intensity change.