Interconnect structure and methods of forming the same

A method for forming an interconnect structure, comprising:

• forming a conductive layer over a dielectric layer;
• forming one or more openings in the conductive layer;
• forming a blocking layer on exposed portions of the dielectric layer;
• selectively forming barrier layers on the conductive layer;
• removing the blocking layer;
• forming a dielectric material directly on the dielectric layer and between adjacent portions of the conductive layer;
• and
• performing a planarization process until the conductive layer is exposed.

A method for forming an interconnect structure, comprising:

• forming a conductive layer over a dielectric layer;
• forming one or more openings in the conductive layer to expose portions of the dielectric layer, wherein the one or more openings separates the conductive layer into one or more portions;
• forming a blocking layer on an exposed surface of the dielectric layer;
• forming barrier layers on the portions of the conductive layer;
• removing the blocking layer;
• forming a capping layer on the barrier layers and the dielectric layer;
• forming a sacrificial layer in the one or more openings and over a hard mask;
• recessing the sacrificial layer to a level below a top surface of the portions of the conductive layer;
• forming a support layer on the capping layer and the recessed sacrificial layer;
• forming a dielectric material on the support layer to fill remaining portions of the one or more openings;
• removing the sacrificial layer to form an air gap between neighboring portions of the conductive layer;
• and
• performing a planarization process until the portions of the conductive layer are exposed.