Fabrication of Nanometer-Scale Features by Controlled Isotropic Wet Chemical Etching

An inexpensive fabrication technique for transferring the edges of a patterned mask layer into an underlying, thin metal film is found in controlled undercutting by isotropic wet etching. This technique generates structures with critical dimensions as small as 50 nm (see Figure) in a thin film of chromium or aluminum and it is useful for structures that do not require multiple-level registration and that are tolerant of defects.