Forming self-aligned vias in a semiconductor device

摘要

A process for forming a via in a semiconductor device uses a self-aligned metal column to connect metal layers separated by a dielectric. A via is formed in a semiconductor device by: (a) forming three overlying conductive layers on a semiconductor substrate, the second layer being of different material from the first and second layers; (b) simultaneously etching the layers to form a patterned section and to expose part of the substrate; (c) filling the etched gaps with a first dielectric layer which is then planarized to expose the top surface of the patterned section; (d) etching a section of the third conductive layer, using the second conductive layer as an etch-stop, to form a column; and (e) filling the etched gaps with a second dielectric layer which is then planarized to expose the top surface of the column.