Imprinting polymer film on patterned substrates

We have developed a technique to create polymer film patterns on substrates with microstructures using an elastomeric polydimethylsiloxane (PDMS) pad, wherein either a continuous or a patterned film on flat PDMS was used for pattern creation. During patterning of the continuous film, a polymer film is first spin coated onto the elastomer pad, and the pad is then brought into contact with the patterned substrate of interest. Since the PDMS can deform elastically around features on the substrate and its surface has low interfacial energy, films on PDMS can be successfully transferred onto the substrate. The resulting profile of the transferred film would depend on the pattern dimensions of the substrate, polymer properties, and conditions for imprinting. Three distinctive film patterns can be achieved, which we designate as continuous film transfer over microstructures, film transfer on both trenches and protrusions, and film transfer on protrusions. Interestingly, a negative replica of patterns on substrates can be simultaneously created on the PDMS pad in the last patterning process and the pattern can be further utilized in subsequent patterning steps. This affords the capability of transferring a patterned film from the PDMS to the sidewalls of the topographic features. Because of the great versatility of this patterning technique, it can be used to rapidly form channels, conformal coating on a patterned substrate, and micro- or nanometer sized patterns inside trenches of a patterned substrate. (C) 2003 American Vacuum Society.