Capillary Force Lithography: Fabrication of Functional Polymer Templates as Versatile Tools for Nanolithography

The development of low-cost, high-throughput lithographic techniques for the fabrication of sub-100 nm patterns has taken a dominant position in nanofabrication during the last decade. The unrelenting efforts that are undertaken in this field are the result of the corresponding high cost and low accessibility of state-of-the-art lithographic techniques—for example, deep-UV and extreme-UV photolithography, soft X-ray lithography, electron-beam writing, and ion-beam lithography—that are still entailed for large-area fabrication of highresolution patterns. Although these techniques will remain the main technology for the semiconductor industry, soft lithography and nanoimprint lithography (NIL) have made enormous progress as non-photolithographic techniques in several areas of exploratory and scientific research in terms of sub100 nm resolution, reproducibility, and uniformity of the patterns over large areas. Generally, the concept of these nonphotolithographic techniques lies in the exact replication of the structures on a master by (conformal) contact with the substrate of interest. To overcome the reliance on expensive stateof-the-art equipment for the fabrication of the necessary highresolution masters, several innovative strategies have been put forward that extend the capabilities of soft lithography and NIL into the sub-100 nm range. These inexpensive strategies basically exploit the combination of different (aspects of) soft-