Patent ID: 6498635
Filing Date: 2002-12-24
Classification: G02F

Abstract:
A method of forming a device structure that combines insulating materials for silicon nitride alignment posts and optical interference layers with an active device structure in a silicon body comprising:providing a silicon semiconductor wafer, said silicon semiconductor wafer having been provided with a pattern of active device structures therein and thereon; forming a first metallic layer over the surface of said wafer; forming a silicon oxide insulating layer over the surface of said first metallic layer; forming a second metallic layer over the surface of said silicon oxide layer; forming a photoresist mask over the surface of said second metallic layer, said photoresist mask providing a covering over planned pixel locations of liquid-crystal-on-silicon devices; removing said second metallic layer not covered by said photoresist mask, exposing the surface of said layer of silicon oxide; removing said photoresist mask, each said planned pixel retaining said second metallic layer, said retained second metallic layer acting as a mirror reflector for light incident upon said liquid-crystal-on-silicon devices; forming a layer of silicon nitride over the surface of said exposed layer of silicon oxide and said retained second metallic layer, said layer of silicon nitride being of a thickness to achieve a desired height of the alignment posts; forming a photoresist mask over the surface of said silicon nitride layer to cover a location of each planned nitride post; etching said silicon nitride layer, forming said posts of silicon nitride, stopping said etch at said retained second metallic layer and said silicon oxide layer, exposing the surface of said silicon oxide layer; removing said photoresist mask; and forming optical interference layers of silicon oxide/silicon nitride/silicon oxide/silicon- nitride over exposed surfaces of said silicon nitride posts, over the surface of said retained second metallic layer and over the surface of said silicon oxide layer.