“Millipede” – an AFM data storage system at the frontier of nanotribology

Abstract

The “Millipede” data storage concept is based on the parallel operation of a large number of micromechanical levers that function as AFM sensors. The technique holds promise to evolve into a novel ultrahigh-density, terabit-capacity, and high-data-rate storage technology. Thermomechanical writing and reading in very thin polymer (PMMA) films is used to store and sense 30–40 nm sized bits of similar pitch size, resulting in 400–500 Gbit/in² storage densities. High data rates are achieved by operating very large arrays (32×32) of AFM sensors in parallel. Batch-fabrication of 32×32 AFM cantilever array chips has been achieved, and array reading and writing have been demonstrated. An important consideration for the Millipede storage project is the polymer dynamics on the size scale of one bit. Scaling of rheological parameters measured for macroscopic polymer samples is likely to be incorrect due to the finite length of the underlying molecular polymer chain, a size that is comparable to the bit itself. In order to shed light on these issues we performed lifetime studies of regular arrays of nanometer size patterns using light-scattering techniques.