Effective approaches to prevent ambient contaminations impact on the Cobalt Salicide process

Co-Silicide provides lower contact resistance and better device performance, which is widely used in 0.18um and below technology. Typical Co-Salicide process is composed of Co and Ti/TiN capping layer deposition and two RTA (Rapid Thermal Anneal) process steps. The quality of silicide formation will directly influence its device performance. With the character of Co thin film, which is more sensitive to O2, H2O and other acid contaminations, the micro-contamination control is very critical during Co-silicide formation process steps. In this paper, the Co-Silicide poor formation mechanism is studied and some effective improvement methods are proposed.