Interconnection structure and method for manufacturing same

A method for manufacturing an interconnection structure, comprising:

• providing a substrate structure, wherein the substrate structure comprises:
• a substrate,
• an interlayer dielectric layer on the substrate,
• a plurality of first through holes running through the interlayer dielectric layer, and
• a first metal layer filling the plurality of first through holes;
• forming a through hole structural layer on the substrate structure, wherein the through hole structural layer comprises a dual-damascene through hole structure, the dual-damascene through hole structure comprising:
• a second through hole and a third through hole in the through hole structural layer, and
• an opening on the second through hole and the third through hole,
• wherein the first metal layer in one of the first through holes of the plurality of first through holes is exposed in the second through hole,
• wherein the first metal layer in another one of the plurality of first through holes is exposed in the third through hole, and
• wherein the second through hole, the third through hole, and a part of the through hole structural layer between the second through hole and the third through hole are exposed in the opening;
• filling a second metal layer in the second through hole and the third through hole, wherein an upper surface of the second metal layer is lower than an upper surface of the part of the through hole structural layer between the second through hole and the third through hole;
• etching the part of the through hole structural layer between the second through hole and the third through hole so that the upper surface of the part is lower than the upper surface of the second metal layer;
• and
• after etching the part of the through hole structural layer, forming, in the opening, a third metal layer connected to the second metal layer.