Contact resistance between via and conductive line

A method comprising:

• forming a first oxide layer over a substrate;
• forming a first nitride layer over the substrate;
• forming a first conductive feature extending through and directly contacting the first oxide layer and the first nitride layer;
• forming a second oxide layer over the first conductive feature;
• forming a second nitride layer over the first conductive feature;
• forming a via extending through and directly contacting the second oxide layer and the second nitride layer;
• forming a third dielectric layer over the via;
• forming a second conductive feature extending through the third dielectric layer to the via such that the second conductive feature directly contacts the third dielectric layer and the via, wherein the second conductive feature is formed of the same metal material throughout the second conductive feature, wherein the forming of the second conductive feature includes forming the metal material within the third dielectric layer without a barrier layer being disposed around the metal material such that the metal material directly contacts the third dielectric layer and the via;
• and
• forming a third nitride layer directly on the first oxide layer, wherein the third nitride layer directly contacts the first conductive feature after the forming of the second conductive feature extending through the third dielectric layer to the via.

A method comprising:

• forming a first dielectric layer on a substrate, wherein the forming of the first dielectric layer on the substrate includes forming a first nitride layer on the substrate;
• forming a first conductive feature within the first dielectric layer, wherein the first nitride layer directly contacts and covers a bottommost surface of the first conductive feature after the forming of the first conductive feature within the first dielectric layer, the bottommost surface of the first conductive feature facing the substrate;
• forming a second dielectric layer on the first dielectric layer;
• forming a via within the second dielectric layer such that the via directly contacts the second dielectric layer and the first conductive feature;
• forming a third dielectric layer on the second dielectric layer;
• and
• forming a metal layer within the third dielectric layer without a barrier layer being disposed around the metal layer such that the metal layer directly contacts the third dielectric layer and the via, the metal layer being formed of the same material throughout the metal layer.