3D free forms in c-Si via grayscale lithography and RIE

Schematic showing the gray scale technology (a) the exposure laser intensity variation profile (b) CAD layout of test patterns with different exposure intensity, (c) cross section: in case of a positive PR the “dose to clear” is obtained at the interface between the dark red and the light red pattern. (d) Cross section of the pattern transferred into Si after RIE.124