Similar to the photolithography process used in semiconductor device manufacturing, the metal etching process also requires the use of a silver halide film as a mask (photomask) to transfer the image onto the photoresist via UV exposure. The areas of the photoresist masked by the film are not exposed to UV light and are therefore removed during the subsequent development process. The stainless steel exposed by the development process—now unprotected by the photoresist—is etched away by the etching solution, thereby completing the etching process.