Comparison between HDP CVD and PECVD silicon nitride for advanced interconnect applications

High-density plasma CVD (HDP CVD) silicon nitride has been investigated for its use in advanced interconnect applications. Results show that the HDP film has many excellent film properties and has many advantages over the plasma-enhanced CVD (PECVD) silicon nitride film. The HDP film has a higher film density, much lower hydrogen content, in addition to lower polish, wet-etch, and dry-etch rates, than the PECVD film. Therefore, the HDP silicon nitride is suitable and ideal as CMP and etch stop layers, as hard mask, and as Copper diffusion and oxidation barriers in damascene architectures.