Tungsten layer forming method and laminate structure of tungsten layer

Abstract

A tungsten layer is formed on the surface of an object to be treated (e.g., a semiconductor wafer), supplying a process gas which includes a material gas of a tungsten fluoride (e.g., WF6) gas and a reducing gas (e.g., H2 gas) for reducing the material gas. In this case, an intermediate tungsten film forming step is carried out between a nuclear crystalline film forming step of forming a nuclear crystalline film of tungsten on the surface of the object and a main tungsten film forming step of forming a main tungsten film on the nuclear crystalline film. At the intermediate tungsten film forming step, an intermediate tungsten film is formed while the flow ratio of the material gas to the reducing gas is smaller than that at the main tungsten film forming step. Thus, the incubation time T2 after the deposition of the nuclear crystalline film is removed, so that it is possible to enhance the whole mean deposition rate and to improve the uniformity of the thickness between objects to be processed.

Dependencies are inferred from the claim text.