1. Technical Field
A method of forming a gate electrode in a semiconductor device is disclosed and, more specifically, a method of forming a gate electrode which is constructed in a polycide structure is disclosed.
2. Discussion of Related Art
As semiconductor devices become more highly integrated, gate electrodes are constructed with a polycide structure where a metal silicide film is deposited on an upper surface of a polysilicon film to form the gate electrode because of the low resistance of the polysilicon film. In the formation of a gate electrode with a polycide structure, the polysilicon film and a metal silicide film are etched to form a gate electrode pattern having a vertical profile.
After the etching of the tungsten silicide film, the polysilicon film is etched. At the time of etching the tungsten silicide film, some portion of the polysilicon film is recessed. Then, another etching process is performed to pattern the gate electrode on the recessed polysilicon film. As a result, two etching processes are performed on the polysilicon film. Due to the two etching processes, the profile of the polysilicon film has a recessed-shape where the polysilicon is more recessed than the other films.
Since the polysilicon film has the aforementioned profile, it is difficult to form the gate electrode pattern in a proper vertical profile. As a result, the characteristics of the resulting device may be deteriorated as a result of the multiple etching processes.
USPTO Backgrounds
USPTO Backgrounds