Electrically induced structure formation and pattern transfer

The wavelength of light represents a fundamental technological barrier(1) to the production of increasingly smaller features on integrated circuits. New technologies that allow the replication of patterns on scales less than 100 nm need to be developed if increases in computing power are to continue at the present rate(2). Here we report a simple electrostatic technique that creates and replicates lateral structures in polymer films on a submicrometre length scale. Our method is based on the fact that dielectric media experience a force in an electric field gradient(3). Strong field gradients can produce forces that overcome the surface tension in thin liquid films, inducing an instability that features a characteristic hexagonal order. In our experiments, pattern formation takes place in polymer films at elevated temperatures, and is fixed by cooling the sample to room temperature. The application of a laterally varying electric field causes the instability to be focused in the direction of the highest electric field. This results in the replication of a topographically structured electrode. We report patterns with lateral dimensions of 140 nm, but the extension of the technique to pattern replication on scales smaller than 100 nm seems feasible.