Double-Exposure Gray-Scale Photolithography

Three-dimensional photoresist structures may be realized by controlling the transmitted UV light intensity in a process termed gray-scale photolithography. Light modulation is accomplished by diffraction through sub-resolution pixels on a photomask. The number of photoresist levels is determined by the number of different pixel sizes on the mask, which is restricted by mask fabrication….

Authors: Mosher, Lance

Source: University of Maryland