A method for forming a plug metal layer is disclosed and includes the following steps. Performance of an atomic layer deposition (ALD) at least once to form a continuous metal seed layer (CMSL) on a barrier layer, wherein the atomic layer deposition comprise: a mixing gas of hydrogen and silane, such as hydroxy silane or tetrahydroxy silane, being transported on the barrier layer. Next, performance of a purge/vacuum process. Then transporting a reactive gas, such as WF.sub.6, to form the continuous metal seed layer (CMSL). A subsequent cycle step of atomic layer deposition (ALD) can be repeated to form the thickness of the continuous metal seed layer (CMSL) to about 20 to 40 .ANG..