Reduction of plasma-induced damage during intermetal dielectric deposition in high-density plasma

We have attempted to reduce the plasma-induced damage to the thin gate oxides during intermetal dielectric (IMD) gap-fill process by high-density plasma (HDP) chemical vapor deposition (CVD). It was revealed that the optimization of preheating step could reduce the damage. The H₂-based HDP CVD process was also effective in reducing plasma-induced damage compared with the conventional He-based process. The gate oxide failure was reduced remarkably at the low deposition temperatures less than 400°C. Both the significant damage reduction and the excellent gap-fill performance were achieved by the adoption of the phosphorus silicate glass (PSG) using the low temperature H₂-based HDP CVD technique.