Air gap dielectric in self-aligned via structures

摘要

A high speed interconnect structure and methods for making the structure are provided. The interconnect structure includes a first metallization layer having a plurality of metallization lines and a conductive via metallization layer defined over the first metallization layer. The conductive via metallization layer is configured to define self-aligned conductive vias. A non-conformal oxide layer is defined over the first metallization layer and the conductive via metallization layer such that air gaps are positioned between the plurality of metallization lines. A cap oxide layer is then defined over the non-conformal oxide. In this example, a CMP operation can be performed to expose the top surfaces of the conductive vias before a next metallization layer is defined. It should be noted that air gaps are defined without the problems associated with conductive via misalignment.