Study of hybrid nucleation tungsten deposition for shallow trench gap-fill

Abstract

As the semiconductor device gets scaling down and has higher density of transistor to improve performance, device requirements get challenging for conventional tungsten metal process. Specially, in case of DRAM BCAT, preventing structure deformation by zipping effect while depositing metal to fill in trenches is one of challenges to increase pattern density while reducing resistivity and impurities In order to overcome the limitation of conventional tungsten metal process, we developed hybrid nucleation tungsten, which are PNL(pulsed nucleation layer) process combining B2H6 and SiH4, and it proved to improve the process performance on key requirements for 4th generation of 1x nm DRAM buried word line metal.