Method to reduce resistance for a copper (Cu) interconnect landing on multilayered metal contacts, and semiconductor structures formed therefrom
A method of forming a semiconductor structure includes forming a first insulating layer containing a first metal layer embedded therein and on a surface of a semiconductor substrate. The method further includes forming an inter-layer dielectric (ILD) layer on the first insulating layer, and forming at least one via trench structure including a first metallization trench and a via in the ILD layer. In addition, the method also includes depositing a metal material to form a first metallization layer in the first metallization trench, a via contact in the via, and a second metal layer on top of at least a portion of the first metal layer in the opening of the first insulating layer. The first metal layer and the second metal layer constitute a multilayer metal contact located in the opening of the first insulating layer.
1. A semiconductor structure comprising:
a semiconductor substrate including a plurality of semiconductor devices associated therewith;
a first insulating layer located on the semiconductor substrate that includes an opening therein which exposes a portion of the semiconductor substrate including the semiconductor devices;
a multilayered metal contact located within the opening in the first insulating layer, wherein the multilayered metal contact comprises a first metal layer selected from the group consisting of cobalt (Co), tungsten, (W), nickel (Ni), gold (Au) and silver (Ag), and a second copper metal layer disposed above at least a portion of the first metal layer;
an inter-layer dielectric (ILD) layer located on the first insulting layer; and
at least one via trench metallization structure located in ILD layer, wherein the at least one via trench metallization structure includes a first metallization layer therein, and a via including a via contact therein, wherein the via of the at least one via trench metallization structure extends completely through the ILD layer, wherein the via contact contacts the multilayered metal contact located within the opening of the first insulating layer
and wherein there is no liner at an interface between the multilayered metal contact and the via of the at least one via trench metallization structure.
2. The semiconductor structure of claim 1 , wherein the first metallization layer, the via contact, and the second metal layer each comprise copper, wherein the multilayered metal contact in the first insulating layer is a bilayer structure comprising the first metal layer and the second metal layer, and wherein there is substantially no liner at an interface between the first metal layer and the second metal layer.