A novel, micro-contact potential difference probe

A novel, non-vibrating, micro-contact potential difference (CPD) probe fabricated by micromachining has been tested for measurements on a magnetic hard disk drive. The 50 μm diameter probe, with integrated shielding, provides high-resolution surface images as the probe is scanned over the surface of interest. The probe utilizes Parylene as a flexible substrate material that allows it to be bent away from the integrated electronics and closely approach the surface under study. A four-mask process was used to create the micro-CPD probe, including a 500 μm radius, annulus of SU-8 that provides mechanical support for the gold electroplated probe and sputtered shielding. Defects, such as scratches and adhesive tape placed on a magnetic hard disk, were measured at a height of 0.5 mm and rotation speed of 1000–3600 rpm. From these signals the features, were reconstructed from the CPD signal, to determine the feature size.