Non-photolithographic methods for fabrication of elastomeric stamps for use in microcontact printing

This paper describes several methods that generate patterned relief structures for casting the elastomeric stamps required in microcontact printing (mu CP). The relief structures include the following: (1) patterns etched in thin films of silver (200 nm thick) with printed SAMs of hexadecanethiolate as resists; (2) patterned polymeric structures assembled on the surface of a thin film of silver (or gold) that has been patterned with SAMs of hexadecanethiolate; and (3) polystyrene microspheres assembled on a flat surface. Commercial diffraction gratings were also useful as masters. Microcontact printing with poly(dimethylsiloxane) stamps cast from these relief structures was used in combination with selective wet etching to generate patterns in thin films of silver and gold. Although some of these techniques used photolithography once in fabricating the initial masters, they could produce patterns more complex than those on the initial masters. These procedures provide a convenient route to moderately complex patterns with feature sizes ranging from similar to 100 nm to similar to 100 mu m.