Self-aligned contact process for a crown shaped dynamic random access memory capacitor structure

摘要

A process for fabricating a crown shaped, capacitor structure, in a SAC opening, featuring a silicon nitride spacer, located on the walls of a bottom portion of the SAC opening, has been developed. The process features forming a SAC opening in a thick silicon oxide layer, then repairing, or filling, seams or voids, that may be present in the thick silicon oxide layer, at the perimeter of the SAC opening, via formation of a silicon nitride spacer on the sides of the SAC opening. Subsequent processing features: the isotropic removal of a top portion of the silicon nitride spacer; the formation of a polysilicon storage node structure, in the SAC opening; and the recessing of a top portion of the thick silicon oxide layer, resulting in exposure of additional polysilicon storage node, surface area.