Method for forming a dielectric layer with an air gap, and a structure including the dielectric layer with the air gap

A structure, comprising:

• a semiconductor substrate;
• a first dielectric layer and a second dielectric layer above the substrate;
• a respective conductive pattern within each of the first and second dielectric layers, the conductive patterns having sidewalls, the conductive pattern of the second dielectric layer at least partially overlying the conductive pattern of the first dielectric layer;
• a protective dielectric material formed along the sidewalls of the conductive patterns in the first and second dielectric layers,
• at least one of the first and second dielectric layers having an air gap between the protective dielectric material and the respective one of the first and second dielectric layers;
• and
• a capping layer between the first and second dielectric layers, the capping layer isolating the air gap in the one of the first and second dielectric layers from the conductive pattern in the other of the first and second dielectric layers.

A method of forming a semiconductor structure, comprising the steps of:

• (a) providing a first dielectric layer with an opening above a substrate;
• (b) transforming an exposed surface portion of the first dielectric layer in the opening;
• (c) forming a protective dielectric layer along the transformed portion of the first dielectric layer;
• (d) filling the opening with a conductive material;
• and
• (e) removing the transformed portion of the first dielectric layer to form an air gap between the protective dielectric layer and a remaining portion of the first dielectric layer.