METHOD AND APPARATUS FOR FORMING SELF-ALIGNED VIA WITH SELECTIVELY DEPOSITED ETCHING STOP LAYER

摘要

A layer of an interconnect structure is formed over a substrate. The layer contains an interlayer dielectric (ILD) material and a metal line disposed in the ILD. A first etching stop layer is formed on the ILD but not on the metal line. The first etching stop layer is formed through a selective atomic layer deposition (ALD) process. A second etching stop layer is formed over the first etching stop layer. A high etching selectivity exists between the first and second etching stop layers. A via is formed to be at least partially aligned with, and electrically coupled to, the metal line. The first etching stop layer prevents the ILD from being etched through during the formation of the via.

主权项

1. A semiconductor device, comprising:
a first layer of an interconnect structure formed over a substrate, wherein the first layer contains a first dielectric material and a first conductive element disposed in the first dielectric material; a first etching stop layer that is disposed on the first dielectric material of the first layer but not on the first conductive element of the first layer; and a second conductive element disposed over the first layer, wherein the second conductive element is at least partially aligned with, and electrically coupled to, the first conductive element; a second etching stop layer disposed over the first etching stop layer and over the first layer, wherein the second conductive element extends through the second etching stop layer; and a second layer of the interconnect structure disposed over the second etching stop layer, wherein the second layer of the interconnect structure includes a second dielectric material and a third conductive element disposed in the second dielectric material, wherein the third conductive element is disposed over, and electrically coupled to, the second conductive element.