Interconnect with redeposited metal capping and method forming same

A method comprising:

• forming a first conductive feature in a first dielectric layer;
• forming a first metal cap and a second metal cap over and contacting a first portion and a second portion, respectively, of a top surface of the first conductive feature, wherein the second metal cap comprises:
• a first part over and contacting a part of the first metal cap;
• and
• a second part overlapping and contacting the top surface of the first conductive feature;
• forming an etch stop layer over the first dielectric layer;
• forming a second dielectric layer over the etch stop layer;
• and
• forming a second conductive feature in the etch stop layer and the second dielectric layer, wherein the second conductive feature is over and contacting the second metal cap, and wherein the forming the second conductive feature comprises:
• depositing a conductive barrier;
• and
• depositing a conductive region encircled by the conductive barrier, wherein the conductive region and the conductive barrier are in physical contact with a top surface of the second metal cap.

A method comprising:

• forming a first metal cap over and contacting a first conductive feature;
• forming a second metal cap over and contacting the first conductive feature, wherein the first metal cap and the second metal cap are in contact with each other to form a distinguishable interface, and wherein in a cross-sectional view of the second metal cap and the first metal cap, the second metal cap comprises opposing portions on opposing sides of a part of the first metal cap, and the opposing portions are in contact with the first conductive feature;
• forming a dielectric layer over and in contact with the first metal cap;
• and
• forming a second conductive feature over and contacting the second metal cap, wherein the forming the second conductive feature comprises:
• forming a conductive barrier, wherein an outer edge of the conductive barrier is vertically aligned to the distinguishable interface;
• and
• forming a conductive region encircled by the conductive barrier, wherein the conductive region physically contacts the second metal cap.