Abstract: A silicon oxide film is formed to cover a polysilicon plug. A bowing shaped hole is formed. A barrier metal and a metal film are formed, which are successively subjected to prescribed anisotropic etching. Here, because of the RIE-lag effect, the etch rate of the barrier metal becomes smaller in the portion between the side surface of the hole and the metal film than in the other portions, preventing the exposure of the surface of the polysilicon plug. Thus, a semiconductor device ensuring a good electrical connection of metal interconnections is obtained.

Abstract: There is described formation of a contact hole without involvement of damage to an etching stopper film and deterioration of electric characteristics, achieved by means of a self-alignment method. An interlayer oxide film is etched through an opening of a resist mask, and by means of plasma etching through use of a processing gas comprising a mixture of a rare gas and a CF-based gas, thereby tapering a shoulder of the silicon nitride film. Alternatively, a silicon oxide film and a silicon nitride film are continually etched through an opening of the resist mask, by means of plasma etching through use of a CH2F2 gas added to a mixed gas including a rare gas and a C4F8 gas.

Abstract: There is described formation of a contact hole without involvement of damage to an etching stopper film and deterioration of electric characteristics, achieved by means of a self-alignment method. An interlayer oxide film is etched through an opening of a resist mask, and by means of plasma etching through use of a processing gas comprising a mixture of a rare gas and a CF-based gas, thereby tapering a shoulder of the silicon nitride film. Alternatively, a silicon oxide film and a silicon nitride film are continually etched through an opening of the resist mask, by means of plasma etching through use of a CH2F2 gas added to a mixed gas including a rare gas and a C4F8 gas.

Abstract: A gate electrode includes a polycrystalline silicon layer, a barrier layer and a metal layer. The metal layer and barrier layer includes for example W and RuO2 layers, respectively. In forming the gate electrode, the metal layer and barrier layer are etched using at least one of the barrier layer and polycrystalline silicon layer as an etching stopper.