At present, Cu (copper) is being used as a wiring material. In an RF-CMOS device
as a combination of an RF analog device and CMOS logic device, two electrodes of
a MIM capacitor are formed from Cu having a large diffusion coefficient. To prevent
Cu from diffusing to the capacitor insulating film of the MIM capacitor, diffusion
prevention films having a function of preventing diffusion of Cu are interposed
between the capacitor insulating film and the two electrodes. As a result, Cu forming
the electrodes does not diffuse to the capacitor insulating film.
