Semiconductor device and manufacturing method thereof

#1. Field of the Invention

#The present invention relates to a semiconductor device and a manufacturing method thereof in which, for example, a multilayered structure inclusive of Cu wirings is applied to an MIM capacitor and, more particularly, to those in which it is taken into consideration to improve a Q value in a high-frequency circuit by lowering a resistance and prevent Cu diffusion from the multilayered structure inclusive of the Cu wirings.

#2. Description of the Related Art

#FIG. 1 is a diagrammatic sectional view showing a semiconductor device manufacturing method according to a first embodiment of the present invention in the order of its processes;

#FIG. 2A, FIG. 2B, and FIG. 2C are diagrammatic sectional views showing the semiconductor device manufacturing method according to the first embodiment in the order of its processes, subsequently to FIG. 1;

#FIG. 3A, FIG. 3B, and FIG. 3C are diagrammatic sectional views showing the semiconductor device manufacturing method according to the first embodiment in the order of its processes, subsequently to FIG. 2A, FIG. 2B, and FIG. 2C;

#<Basic Gist of Present Invention>

#With the aim of lowering the resistance of an MIM capacitor, the inventor of the present invention has thought of a capacitor structure which can lower the resistance to an extent substantially equivalent to that in a case when a lower electrode of the MIM capacitor is backed with a low resistance wiring comprised of Cu or the like and the lower electrode is comprised of Cu.

#In this case, however, there is a concern about a problem that Cu atoms easily diffuse to an insulator such as a silicon oxide film which is often used for an interlayer insulation film. The inventor of the present invention has devised a material used for the lower electrode and the backing structure of a Cu wiring to prevent the exposure of Cu to the insulator, thereby maintaining a function of the wiring. Specifically, the following backing structure has been thought of. Namely, a conductive film, such as titanium nitride (TiN), having a Cu diffusion preventive function is used for the lower electrode and the lower electrode embraces the surface of the Cu wiring. This structure enables the connection of the Cu wiring and the lower electrode while eliminating a portion of Cu exposed to the insulator.