Effect of silane flowing time on W volcano and plug formation

Abstract

W volcano is one of the defects in semiconductor devices. The presence of defects causes metal line bridges and thus device malfunction. The decomposition of SiH4 gas into Si atoms as nucleation sites is crucial for W film deposition. Here, we investigate the phenomenon in which the flowing time of SiH4 gas appears to dominate both W volcano formation and the degree of W film filling in a hole; the density of W volcanoes is increased with an increase of SiH4 flowing time. The volcano-free process and step-coverage of a W plug with various SiH4 flowing times are evaluated, and a formation mechanism is also proposed.