Vertical interconnect features and methods of forming

A method of forming a semiconductor structure, the method comprising:

• forming a first dielectric layer on a substrate;
• forming a first conductive feature in the first dielectric layer;
• forming a second dielectric layer over the first dielectric layer and the first conductive feature;
• forming a first opening extending through the first dielectric layer and the second dielectric layer;
• depositing a first conductive material along a bottom of the first opening, sidewalls of the second dielectric layer in the first opening being free of the first conductive material;
• forming a second conductive material over the first conductive material, wherein at least a portion of the sidewalls of the second dielectric layer in the first opening is free of the second conductive material;
• forming a patterned mask over the second dielectric layer, the patterned mask covering the first opening and exposing a region of the second dielectric layer vertically over the first conductive feature;
• removing a portion of the second dielectric layer from the region exposed by the patterned mask, removing the portion of the second dielectric layer forming a second opening exposing a portion of the first conductive feature;
• removing the patterned mask;
• and
• depositing a third conductive material, the third conductive material filling the first opening and the second opening, wherein the first conductive feature and the third conductive material in the second opening form a first conductive element, wherein the first conductive material, the second conductive material, and the third conductive material in the first opening form a second conductive element.

A method of forming a semiconductor structure, the method comprising:

• forming a first dielectric layer on a substrate, the first dielectric layer having a first conductive feature therein, wherein an upper surface of the first dielectric layer is level with an upper surface of the first conductive feature;
• forming a second dielectric layer over the first dielectric layer and the first conductive feature;
• forming a first opening extending through the first dielectric layer and the second dielectric layer exposing a second conductive feature;
• after forming the first opening extending through the first dielectric layer and the second dielectric layer, forming a first conductive material in the first opening, wherein an upper surface of the first conductive material is recessed below the upper surface of the first dielectric layer;
• forming a second conductive material over the first conductive material in the first opening;
• after forming the second conductive material, forming a second opening in the second dielectric layer, the second opening exposing a portion of the first conductive feature;
• and
• depositing a third conductive material in the first opening and the second opening.