Lithographically induced self-construction of polymer microstructures for resistless patterning

We have discovered and developed a method that can directly pattern polymer microstructures of arbitrary shapes without using a resist, exposure, chemical development, and etching. A mask with protruded patterns is placed a distance above an initially flat polymer film cast on a substrate. During a heating cycle that raises the temperature above the polymer's glass transition temperature and then cooled back to the room temperature, we found that the polymer was attracted to the mask protrusions on their own, forming the mesas that have a lateral dimension identical to that of the mask protrusions, a height equal to the distance between the mask and the substrate, and a relatively steep sidewall. The method, termed lithographically induced self-construction, is important to the fabrication of polymer electronic and optoelectronic devices.