A self-aligned airgap interconnect scheme

Abstract

A new air-gap interconnect scheme with no additional patterning step successfully resolves the issue of unlanded via, and provides good interconnect reliability and improved packaging margin. We demonstrate that the insertion of airgaps in a very low-k dielectric (k=2.5) reduces the RC value of a 0.07um/0.07um comb structure by ∼14%, which is equivalent to an effective dielectric constant about 2.2.