Method of forming self-aligned contact structure with locally etched gate conductive layer

Abstract

A method of forming a self-aligned contact structure with a locally etched conductive layer comprises the steps of: preparing a substrate formed with gate structures comprising a first conductive layer, a second conductive layer, and an insulating layer; depositing a photoresist material layer on the substrate; performing a lithographic step with a bit-line contact node photomask or a bit-line contact photomask to expose a portion of the surface of the substrate; etching the exposed second conductive layer with an etchant; removing the remaining photoresist material layer; forming a sidewall spacer on the sidewalls of each gate structure; forming a dielectric layer to cover the substrate; and performing lithographic and etching steps to remove the dielectric layer and to form self-aligned contact structure.