Fang said the newly created "S4 process" uses a patterned superionic material as a stamp, and etches a metallic film by an electrochemical reaction. In superionic materials, metal ions can move nearly freely around the crystal lattice. Such mobile materials can also be used in batteries and fuel cells.
"The most difficult step in the S4 process is making the stamp extremely flat and smooth," said graduate student Keng H. Hsu, the paper’s lead author. "Currently, our resolution for patterning details is 50 nanometers. As better tools for engraving the stamps are developed, we will achieve finer resolution.
Unlike conventional processing – in which patterns are first placed on photoresist, followed by metal deposition and subsequent etching – the S4 process creates high-resolution metallic nanopatterns in a single step, potentially reducing manufacturing costs and increasing yields.