BLOκTM-a low-κ dielectric barrier/etch stop film for copper damascene applications

A low-κ dielectric barrier/etch stop film has been developed for use in copper damascene processes. The film is deposited using Dow Corning^R organosilicon gas as a precursor in a single-wafer PECVD chamber, and has a lower dielectric constant (⩽5) compared to the SiC film (>7) generated by SiH₄ and CH₄ and plasma silicon nitrides (>7). This film is amorphous and composed of silicon, carbon and hydrogen (a-SiC:H). The film characterization, including physical, electrical, copper diffusion barrier properties, and etch selectivity demonstrated that this film is a good barrier/etch stop for low-κ copper damascene applications. Due to its low dielectric constant, low effective κ values can be achieved in damascene devices. This film has been named BLOκ^TM (barrier low κ) (Pai and Ting, 1989)