Cu/ULK (k=2.0) integration for 45 nm node and below using an improved hybrid material with conventional BEOL processing and a late porogen removal

Conventional Cu-ULK integration schemes lead to a drastic increase of the dielectric constant due to porous material degradation during process steps. In this paper, a post-integration porogen removal approach is studied to overcome this issue. Material optimization is presented (k=2.0) allowing the use of conventional BEOL integration processes such as oxygen-based etch chemistry, metal CVD barrier deposition and standard CMP process for dense low k. An integrated k value lower than 2.2 is obtained.