Patent ID: 9704798
Date: 2017-07-11
CPC Classifications: H01L

Claim:
1. A metal interconnect structure, comprising: a dielectric layer on a substrate; an opening in the dielectric layer, wherein the opening has opening sidewalls and exposes a conductive region of at least one of the substrate and an additional interconnect structure; a first conformal thin film layer (first layer) on the conductive region and the opening sidewalls; a second conformal thin film layer (second layer) within the opening and on a portion of the first layer, and a third conformal thin film layer (third layer) within the opening and on the first layer; wherein (a) the third layer directly contacts the first and second layers, (b) the opening sidewalls continuously taper inward along each of a bottom, a middle, and a top of the opening so that the opening is narrower at its top than at its bottom, and (c) a horizontal axis, parallel to the substrate, intersects a second layer sidewall portion that tapers outward and an opening sidewall portion that tapers inward.