Prototyping of masks, masters, and stamps/molds for soft lithography usingan office printer and photographic reduction

This paper describes a practical method for the fabrication of photomasks, masters, and stamps/molds used in soft lithography that minimizes the need for specialized equipment. In this method, CAD files are first printed onto paper using an office printer with resolution of 600 dots/in. Photographic reduction of these printed patterns transfers the images onto 35-mm film o r microfiche. These photographic films can be used, after development, as p hotomasks in 1:1 contact photolithography. With the resulting photoresist m asters, it is straightforward to fabricate poly(dimethylsiloxane) (PDMS) st amps/molds for soft lithography, This process can generate microstructures as small as 15 mu m; the overall time to go from CAD file to PDMS stamp is 4-24 h, Although access to equipment-spin coater and ultraviolet exposure t ool-normally found in the clean room is still required, the cost of the pho tomask itself is small, and the time required to go from concept to device is short. A comparison between this method and all other methods that gener ate film-type photomasks has been performed using test patterns of lines, s quares, and circles. Three microstructures have also been fabricated to dem onstrate the utility of this method in practical applications.