Interconnect structures with airgaps and dielectric-capped interconnects

A method comprising:

• forming a metallization level including a first interconnect and a second interconnect in an interlayer dielectric layer;
• depositing a first section of a first dielectric layer on a first top surface of the first interconnect a second section of the first dielectric layer on a second top surface of the second interconnect, and a third section on a first portion of the interlayer dielectric layer;
• removing the third section of the first dielectric layer selective to the first section and the second section of the first dielectric layer to expose the first portion of the interlayer dielectric layer;
• removing the first portion of the interlayer dielectric layer to form a cavity with an entrance between the first interconnect and the second interconnect;
• and
• depositing a second dielectric layer on surfaces surrounding the cavity that pinches off to encapsulate an airgap inside the cavity,
• wherein the first section and the second section of the first dielectric layer are comprised of aluminum nitride, and the third section of the first dielectric layer is comprised of aluminum oxynitride.