Cracking-assisted photolithography for mixed-scale patterning and nanofluidic applications

Cracks are observed in many environments, including walls, dried wood and even the Earth’s crust, and are often thought of as an unavoidable, unwanted phenomenon. Recent research advances have demonstrated the the ability to use cracks to produce various micro and nanoscale patterns. However, patterns are usually limited by the chosen substrate material and the applied tensile stresses. Here we describe an innovative cracking-assisted nanofabrication technique that relies only on a standard photolithography process. This novel technique produces well-controlled nanopatterns in any desired shape and in a variety of geometric dimensions, over large areas and with a high throughput. In addition, we show that mixed-scale patterns fabricated using the ‘crack-photolithography’ technique can be used as master moulds for replicating numerous nanofluidic devices via soft lithography, which to the best of our knowledge is a technique that has not been reported in previous studies on materials’ mechanical failure, including cracking. Cracks in material are not always unwanted; sometimes, they can be manipulated to produce micro and nanoscale patterns. Here, Kim et al. report a cracking-assisted nanofabrication technique based on conventional photolithography process, which allows accurate control over the geometry of the nanopatterns in arbitrary shape.