Copper-based tunneling barrier layer for stress reduction in copper structures and methods for forming the same

A method of forming a device structure, comprising:

• forming a first copper-containing metal interconnect structure over a first dielectric material layer;
• converting a surface portion of the first copper-containing metal interconnect structure into a copper-based tunneling barrier layer;
• forming at least one additional dielectric material layer over the first dielectric material layer and the copper-based tunneling barrier layer;
• forming a cavity through the at least one additional dielectric material layer such that a surface segment of the first copper-containing metal interconnect structure or the copper-based tunneling barrier layer is exposed underneath the cavity;
• and
• forming a second copper-containing metal interconnect structure in the cavity on the copper-based tunneling barrier layer.

A device structure comprising:

• a first copper-containing metal interconnect structure formed within a first dielectric material layer;
• a copper-based tunneling barrier layer located on a surface of the first copper-containing metal interconnect structure;
• and
• a second copper-containing metal interconnect structure embedded in a second dielectric material layer that overlies the first dielectric material layer, wherein the second copper-containing metal interconnect structure is in direct contact with the copper-based tunneling barrier layer.