Thermal Chemical Vapor Deposition of Bis(Tertiary-Butylamino)Silane-based Silicon Nitride Thin Films Equipment Design and Process Optimization

Sub-90 nm device design presents challenges for lowering thermal budget as well as depositing uniform and conformal thin films for front-end-of-line silicon nitride applications. Among other low-temperature precursors for silicon nitride film deposition, bis(tertiary-butylamino)silane (BTBAS) has gained acceptance for critical applications such as spacer. This paper describes BTBAS based silicon nitride film deposition process optimization for spacer and etch stop applications. The single-wafer chamber design can control and tune the film with respect to deposition rate, film composition, wet etch rate, and film mechanical stress by adjustment of process conditions such as temperature, pressure, and gas flow rates. Computational flow and thermal simulations are employed to optimize chamber design to achieve uniform thin films.