Novel low-k SiOC (k=2.4) with superior tolerance to direct polish and ashing for advanced BEOL integration

Abstract

We established novel SiOC (k=2.4) with higher process damage tolerance. The SiOC was deposited using organo-silane with acetylene bond as a precursor of plasma enhanced chemical vapor deposition (PECVD). The precursor takes high concentration of carbon in the SiOC and the SiOC has closed pores since deposited without using any porogens, therefore lower damage by ashing and direct Cu polish are achieved. We fabricated Cu wirings using direct polish. We confirmed that dielectric constant of the SiOC did not increase after ashing and direct polish process and maintained k=2.4.