Nanoscale patterning in ambient conditions using liquid electromigration

Abstract

Electric field can induce long range flow in liquid materials. This phenomenon is known as liquid electromigration. In particular case of Cr thin film deposited on an insulating substrate, application of high electric-field between two point electrodes results in liquefaction and subsequent flow of the liquefied material in a radially symmetric fashion away from the cathode. This electric field driven material transport phenomenon has been used for a new patterning technique, named electrolithography. A negatively biased scanning probe is used to etch a thin Cr film according to a desired pattern. Then the pattern is transferred to new materials using a polymer layer below the metal film. Electrolithography does not need any UV or e-beam source, and can be performed in ambient condition. We have achieved pattern resolutions of 9 nm on the polymer and 40 nm on transferring the pattern to other materials. In this work, with the help of electrolithography, we have patterned large areas using vector scan technique. This improves throughput of the process by a significant order.