Thermal treatment and underlayer effects on silane and dichlorosilane based tungsten silicide for deep sub-micron interconnection processes

This paper presents the use of silane and dichlorosilane based tungsten silicide in deep submicron interconnection process. The modified annealing silicidation treatment, described in this paper, can extend even silane-based tungsten silicide suitable for 0.35 μm level contact technology. More than 3 orders of contact resistance is reduced. Dichlorosilane based tungsten silicide outperforms silane based tungsten silicide because of its better step coverage from TEM direct evidence. The modified annealing silicidation treatment using large nitrogen flow can also lower about 20% of contact resistance for dichlorosilane based tungsten silicide. Our study also indicates the contact resistance dependence on underlayers where tungsten silicide grown on amorphous silicon can achieve lower contact resistance compared with that on grainy polysilicon underlayer. This work provide a promising manufacturable solution to deep submicron high aspect ratio contact technology