Self-forming barrier for subtractive copper

An electrical device comprising:

• a dielectric layer;
• and
• at least one electrically conductive structure within said dielectric layer, the at least one electrically conductive structure comprising a copper containing core and a barrier layer comprising manganese present on the sidewalls of the copper containing core so that the barrier layer is present between the copper containing core and the dielectric layer, the barrier layer being continuous and uniform layer having a lower surface coplanar with a lower surface of the copper containing core, wherein the copper containing core includes an upper manganese containing regions at an upper surface of the copper containing core.

An electrical device comprising:

• a dielectric layer;
• and
• at least one electrically conductive structure within said dielectric layer, the at least one electrically conductive structure comprising a copper containing core and a barrier layer comprising manganese present on the sidewalls of the copper containing core so that the barrier layer is present between the copper containing core and the dielectric layer, the barrier layer being continuous and uniform layer having a lower surface coplanar with a lower surface of the copper containing core, wherein the copper containing core includes an upper manganese containing regions at an upper surface of the copper containing core and a lower manganese containing regions at a lower surface of the copper containing core.