Interconnect structure having an etch stop layer over conductive lines

A method comprising:

• forming a conductive feature in a first dielectric layer disposed over a substrate;
• depositing an etch stop layer on the first dielectric layer and the conductive feature, wherein a top surface of the etch stop layer adjacent the conductive feature is at a height different from another top surface of the etch stop layer directly over the first dielectric layer;
• depositing a second dielectric layer over the etch stop layer;
• performing a first etching process to define a track trench within the second dielectric layer;
• forming a material on the second dielectric layer and within the track trench;
• performing a second etching process to the second dielectric layer and the etch stop layer to form a via hole that extends through the material within the track trench to expose the conductive feature;
• and
• forming a via in the via hole.

A method comprising:

• providing a device that includes:
• a substrate;
• a first dielectric layer disposed over the substrate;
• and
• a conductive feature disposed in and extending above the first dielectric layer;
• forming an etch stop layer on the first dielectric layer and the conductive feature, the etch stop layer having a conformal cross-sectional profile such that a first portion of the etch stop layer disposed over the conductive feature has a top surface at a first height, and a second portion of the etch stop layer has a top surface at a second height that is less than the first height;
• depositing a second dielectric layer over the etch stop layer;
• performing a lithographic process to define a via hole, wherein the etch stop layer includes a side portion of the etch stop layer extending between the top surface of the first portion and the top surface of the second portion;
• etching the second dielectric layer and the etch stop layer to form a via hole that exposes the conductive feature;
• and
• forming a via in the via hole, wherein the via hole is such that the via in the via hole has a bottommost surface and an entirety of the bottommost surface of the via physically contacts the side portion of the etch stop layer.