Patent ID: 9613856
Date: 2017-04-04
CPC Classifications: H01L

Claim:
1. A method comprising: forming a first conductive feature over a substrate; forming a dielectric layer over the first conductive feature; forming a trench in the dielectric layer, wherein the trench has a first width in its lower portion and a second width in its upper portion, wherein the second width is greater than the first width, wherein the first conductive feature is exposed within the trench; forming a first barrier layer in the trench, wherein the first barrier layer has a first portion disposed over the dielectric layer and a second portion disposed over the first conductive feature; applying a thermal treatment to convert the first portion of the first barrier layer to a second barrier layer; after the thermal treatment, exposing the first conductive feature in the trench by removing the second portion of the first barrier layer while keeping a portion of the second barrier layer disposed over the dielectric layer; and forming a second conductive feature in the trench after the exposing of the first conductive feature.