Interconnect structure including air gaps enclosed between conductive lines and a permeable dielectric layer

An electrical device comprising:

• a plurality of electrically conductive lines on a substrate that are positioned in an array having parallel lengths;
• a plurality of air gaps between the plurality of electrically conductive lines in a same level as the plurality of electrically conductive lines, wherein an air gap is present between each set of adjacent electrically conductive lines, and each air gap includes a sidewall including at least one curvature;
• first and second portions of a permeable dielectric material disposed directly on the plurality of electrically conductive lines and the plurality of air gaps and each having a top surface at a substantially same height throughout an entirety of the first and second portions;
• and
• at least one interconnect in electrical communication with a corresponding one of the plurality of electrically conductive lines and having a bottom surface adjacent to the first and second portions of the permeable dielectric material, the at least one interconnect including:
• a first region disposed on a second region having different widths;
• the second region extending over a corresponding one of the plurality of air gaps such that a bottom surface of the at least one interconnect provides a first portion of an upper surface of the corresponding air gap, and a bottom surface of the second portion of the permeable dielectric material provides a second portion of the upper surface of the corresponding air gap;
• an adhesion layer that extends into only an upper portion of the corresponding air gap;
• and
• an electrically conductive fill within the first and second regions that is obstructed from extending into the corresponding air gap by the adhesion layer so that the electrically conductive fill cannot extend into a lower portion of the corresponding air gap.