A simple lithographic method employing 172 nm vacuum ultraviolet light to prepare positive- and negative-tone poly(methyl methacrylate) patterns

We successfully prepared both positive- and negative-tone patterns by applying poly(methyl methacrylate) (PMMA) as a photoresist. A positive-pattern was prepared by lithography through a photomask using 172 nm vacuum ultraviolet (VUV) light under the pressure of 103 Pa. A negative-pattern was prepared using the same VUV light under the reduced pressure of 10 Pa, followed by rinsing with toluene solution. At 103 Pa, the irradiated PMMA was effectively decomposed and eliminated. On the other hand, at 10 Pa, the irradiated PMMA became cured and resistant to etching. We subsequently utilized these positive- and negative-tone patterns as templates on indium–tin-oxide surfaces to electrodeposit copper microstructures with 10 µm lines and spaces.