Abstract: The present invention relates to a metallization technique of a semiconductor device, more specifically to a semiconductor device having a wiring or plug of a suitable structure for high integration and a method for fabrication of the semiconductor device. The semiconductor device comprises a base substrate 10; an inter-layer insulation film 20 including a first insulation film 16 formed on the base substrate and a second insulation film 18 formed on the base substrate, and having a contact hole 22 which reaches the base substrate 10; and a conducting film 24 formed on an inside wall and a bottom of the contact hole 22, a width of the contact hole in the first insulation film 16 being larger than a width of the contact hole 22 in the second insulation film 18. The conducting film 24 on the inside wall of the contact hole 22, and the conducting film 24 on the bottom of the contact hole 22 is uninterrupted on a boundary.

Abstract: The semiconductor device manufacturing method includes the step of forming a second tungsten film on a first tungsten film, which is formed by using a reduction gas not-containing diborane, by using a gas containing the diborane, or forming the second tungsten film on the first tungsten film after the first tungsten film has been exposed to the gas containing the diborane.