A method for manufacturing capacitors is disclosed. The method is applicable to a capacitor whose upper electrode area is smaller than the lower electrode area. It is featured in that a material, such as a TiN hard mask, is inserted between the conventional electrode metal layer and photo resist layer. This enables one to perform the in-situ photo resist layer removal step after dry etching the upper electrode metal. Since the photo resist layer removal step uses oxygen plasma, the surface of the lower electrode polysilicon is formed with a protective oxide layer because the dielectric layer is etched during the process of dry etching the upper electrode metal. Using the disclosed method can solve the corrosion problem on the upper electrode metal and avoid the lower electrode polysilicon from being corroded by the wet etchant.
