Patent ID: 6323127
Filing Date: 2001-11-27
Classification: H01L

Abstract:
A method for forming a noble metal electrode comprising the steps of:(a) forming an electrode seed layer on a surface of a substrate;(b) forming a silicon nitride layer on said electrode seed layer;(c) forming a layer of silicon oxide on said silicon nitride layer;(d) providing a patterned photoresist mask over said layer of silicon oxide and etching exposed portions of said silicon oxide until portions of said silicon nitride layer are exposed, and sidewalls of silicon oxide remain above the exposed nitride layer to define spaces above said exposed silicon nitride layer;(e) forming polysilicon sidewall spacers on said sidewalls;(f) forming additional silicon oxide in said spaces whereby said spaces are completely filled;(g) removing said polysilicon sidewall spacers to expose portions of said nitride layer and to create annular channels having silicon oxide channel sidewalls;(h) providing silicon nuclei on said channel sidewalls and oxidizing the nuclei to create a roughened channel wall surface;(i) removing said silicon nitride layer at said channels to expose said seed layer;(j) forming a noble metal layer in said channel to at least partially fill the same;(k) removing said silicon oxide, said silicon nitride layer, and said seed layer external to said annular channels; and(l) removing any remaining portions of said silicon oxide and silicon nitride interior to said annular channels to provide an electrode having a cylindrical shape and roughened inner and outer surfaces.