Selective deposition of barrier layer

A method comprising:

• depositing a metal nitride layer and depositing a metal layer over a first dielectric layer, wherein a first electrically conductive structure of a multilayer interconnect (MLI) structure is disposed in the first dielectric layer and the metal nitride layer is disposed between the metal layer and the first dielectric layer;
• depositing a hard mask layer over the metal layer;
• patterning the hard mask layer, the metal nitride layer, and the metal layer, wherein the patterning includes etching the metal nitride layer and the metal layer using the hard mask layer as an etch mask, wherein remainders of the metal nitride layer and the metal layer after the patterning form a second electrically conductive structure of the MLI structure and the second electrically conductive structure is directly on the first electrically conductive structure;
• after performing a treatment process that reduces a surface hydrophilicity of the hard mask layer and the first dielectric layer, depositing metal nitride liners along sidewalls of the metal nitride layer and sidewalls of the metal layer, wherein the metal nitride liners form a portion of the second electrically conductive structure;
• depositing a second dielectric layer over the first dielectric layer, wherein the second electrically conductive structure is disposed in the second dielectric layer;
• and
• performing a planarization process on the second dielectric layer, wherein the planarization process removes the hard mask layer.

A method comprising:

• forming a first electrically conductive contact in a first dielectric layer;
• forming a second electrically conductive contact directly on the first electrically conductive contact, wherein the first electrically conductive contact electrically connects the second electrically conductive contact to an underlying electrically conductive feature;
• performing a treatment process on exposed surfaces of the first dielectric layer and exposed surfaces of an etch mask used to form the second electrically conductive contact, wherein the etch mask is disposed on a top of the second electrically conductive contact;
• selectively growing metal nitride on sidewalls of the second electrically conductive contact relative to the exposed, treated surfaces of the first dielectric layer and the exposed, treated surfaces of the etch mask;
• forming a second dielectric layer over the first dielectric layer, wherein the second electrically conductive contact is disposed in the second dielectric layer, the metal nitride is disposed between the second electrically conductive contact and the second dielectric layer, the second dielectric layer has a first composition different than a second composition of the first dielectric layer, and the etch mask is removed when forming the second dielectric layer;
• forming a third dielectric layer over the second dielectric layer, wherein the third dielectric layer has a third composition different than the second composition;
• forming a fourth dielectric layer over the third dielectric layer, wherein the fourth dielectric layer has a fourth composition different than the third composition;
• and
• forming a third electrically conductive contact in the third dielectric layer and the fourth dielectric layer, wherein the third electrically conductive contact is directly on the second electrically conductive contact and the second electrically conductive contact electrically connects the first electrically conductive contact and the third electrically conductive contact.