SEMICONDUCTOR DEVICE AND ITS MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To solve the problem, raised by a DRAM with a design rule finer than 0.15 μm that a dielectric film having a high dielectric constant and a plug material come into contact with each other and leakage currents become larger, because no sufficient overlapping margin is available between a capacitor lower electrode and a capacitor lower electrode plug. SOLUTION: The capacitor lower electrode is formed on the projecting section of the capacitor lower electrode plug exposed on an interlayer insulating film by a film forming method, such as the sputtering method, etc., by which poor step coverage is obtained. When the electrode is formed in such a structure, the plug and dielectric film having a high dielectric constant can be separated effectively electrically from each other, because the dielectric film is formed thick on the projecting section of the plug but is not formed on the side face of the plug. In addition, since the capacitor lower electrode can be formed on the capacitor lower electrode plug in a self-aligned way by using the structure and manufacturing method, the problem of the insufficient overlapping margin can be solved.