Tip-based data storage using micromechanical cantilevers

We describe a micromechanical approach to data storage based on the atomic force microscope. The approach uses a sharp tip on the end of a soft micromachined cantilever. The tip sits in contact with a polymer substrate which contains topographic features representing data. Writing is performed by heating the tip with a laser, which softens the polymer substrate and allows the tip to create a pit. Reading is done by measuring the small deflection of the cantilever as the tip rides over the feature. In this way, areal densities more than 20 times that of optical recording have been achieved. For this purpose, we have fabricated Si3N4 cantilevers with integrated pyramidal tips which have mass as low as 0.3 ng, 30 times less mass than the smallest commercially available cantilevers. With these cantilevers, we have demonstrated reading real data at rates exceeding 1 Mbit/s. © 1995.