Application of Mn for damage restoration after etchback

A method of making a back end of line interconnect structure, comprising:

• providing a first interconnect layer, a first cap layer over the first interconnect layer, and a second interconnect layer over the first cap layer, the first interconnect layer comprising a first conductive feature and a first dielectric layer, the second interconnect layer comprising a second dielectric layer and an opening comprising a via and a trench, the via extending through the first cap layer to the upper surface of the first conductive feature;
• forming a first barrier layer over the sidewalls and bottom surface of the opening;
• removing a portion of the first barrier layer at the bottom of the via and exposing an upper portion of the first conductive feature in the via;
• forming a Mn-comprising barrier layer over the first barrier layer over the sidewalls and bottom surface of the opening;
• forming a seed layer over the Mn-comprising barrier layer;
• forming a second conductive material in the opening over the seed layer by electrical plating;
• and
• annealing the Mn-comprising barrier layer to form manganese oxides in the Mn-comprising barrier layer.

A method of making a back end of line interconnect structure, comprising:

• providing a first interconnect layer, a first cap layer over the first interconnect layer, and a second interconnect layer over the first cap layer, the first interconnect layer comprising a first conductive feature and a first dielectric layer, the second interconnect layer comprising a second dielectric layer and an opening comprising a via and a trench, the via extending through the first cap layer to the upper surface of the first conductive feature;
• forming a first barrier layer over the sidewalls and bottom surface of the opening;
• removing a portion of the first barrier layer at the bottom of the via and exposing an upper portion of the first conductive feature in the via;
• forming a Mn-comprising barrier layer over the first barrier layer over the sidewalls and bottom surface of the opening, the Mn-comprising barrier layer comprising manganese and at least one seed metal;
• forming a second conductive material in the opening over the Mn-comprising barrier layer by electrical plating;
• and
• annealing the Mn-comprising barrier layer to form manganese oxides in the Mn-comprising barrier layer.