Wire structure for low resistance interconnects

A structure, comprising:

• a wafer;
• a first interlayer dielectric disposed on the wafer;
• a second interlayer dielectric disposed on the first interlayer dielectric;
• at least one interconnect wire embedded in the first interlayer dielectric and the second interlayer dielectric;
• a first barrier layer separating a bottom half of the at least one interconnect wire from the first interlayer dielectric;
• and
• a second barrier layer separating a top half of the at least one interconnect wire from the second interlayer dielectric, wherein a first portion of the top half of the at least one interconnect wire has vertical sidewalls, wherein a second portion of the top half of the at least one interconnect wire and the bottom half of the at least one interconnect wire have flared sidewalls, and wherein the first barrier layer has a different composition from the second barrier layer,
• wherein the first barrier layer is in physical contact with the flared sidewalls of the bottom half of the at least one interconnect wire, and wherein the second barrier layer is in physical contact with the flared sidewalls of the second portion of the top half of the at least one interconnect wire and in physical contact with the vertical sidewalls of the first portion of the top half of the at least one interconnect wire.

A structure, comprising:

• a wafer;
• a first interlayer dielectric disposed on the wafer;
• a second interlayer dielectric disposed directly on the first interlayer dielectric;
• an interconnect wire embedded in the first interlayer dielectric and the second interlayer dielectric, wherein a first portion of a top half of the interconnect wire has vertical sidewalls, and wherein a second portion of the top half of the interconnect wire and a bottom half of the interconnect wire have flared sidewalls;
• a first barrier layer directly next to the bottom half of the interconnect wire and in direct contact with the first interlayer dielectric;
• and
• a second barrier layer directly next to the top half of the interconnect wire and in direct contact with the second interlayer dielectric, the second barrier layer being materially different from the first barrier layer.