Porous extreme low $κ$ (EL$κ$) dielectrics using a PECVD porogen approach

International audienceThe introduction of new dielectrics into silicon chip interconnection technology, to improve the electrical performance of ultra large-scale integration (ULSI), is marked by continuous revisions to meet the International Technology Roadmap for Semiconductors (ITRS) projection. Amorphous a-SiOC:H ($k$=2.9) deposited by plasma-enhanced chemical vapor deposition (PECVD) from linear precursors is now in scale up towards production. Using other precursors like cyclic siloxanes,$k$ value is reduced to 2.5 at least. The main way to reduce the dielectric constant is to introduce porosity into the film. In this work, a two-step porogen approach is followed to perform extreme low (EL) $κ$($k$