Patent ID: 6464892
Filing Date: 2002-10-15
Classification: B05B,H01J,Y10S

Abstract:
A method for fabricating a microelectromechanical device, comprising the steps of:a) providing a silicon substrate having first and second opposing surfaces; b) doping said first surface with a dopant of a same conductivity as a conductivity of said substrate; c) forming a pad oxide on said first surface; d) forming a silicon nitride film on said pad oxide; e) patterning and etching said silicon nitride film to form at least one silicon nitride contact area on said pad oxide; f) forming first and second silicon oxide layers on said first and second surfaces of said substrate, respectively; g) coating a first photoresist layer on one of said first or said second silicon oxide layers; h) defining a first pattern on said first photoresist layer; i) transferring said first pattern onto said one of said first or said second silicon oxide layers; j) coating a second photoresist layer, defining, and transferring a second pattern onto said one of said first or second silicon oxide layers; k) removing said second photoresist layer; l) coating a third photoresist layer and defining a third pattern onto said one of said first or second silicon oxide layers, said third pattern including as a subset said second pattern; m) etching, after the step of defining said third pattern, said second pattern into said silicon substrate for a first period of time; n) transferring said third pattern onto said one of said first or second silicon oxide layers; o) etching simultaneously, after the step of transferring said third pattern, said second and third patterns into said silicon substrate for a second period of time; p) removing said third photoresist layer if said third photoresist layer occludes said first pattern; q) etching said first pattern into said silicon substrate; r) removing, after step (q), said silicon nitride from said at least one silicon nitride contact area and removing any of said pad oxide beneath said at least one silicon nitride contact area, thereby forming a contact area on said first surface; and s) depositing a metal on said contact area.