Method for precision etching of platinum electrodes

摘要

Disclosed is a method for precision etching of films on in-process integrated circuit wafers. The method is particularly useful for etching films comprising noble metals and is advantageous for use in constructing capacitor electrodes. The method comprises depositing a titanium nitride hard mask over the film to be etched, and thereafter patterning the titanium nitride hard mask with an etchant which is selective to titanium nitride and unselective to the underlying film. The film is then etched using either ion beam milling or reactive ion etching with oxygen as an etching agent. Both etches are highly selective to titanium nitride such that the titanium nitride hard mask can be very thin compared to the film. The presence of the titanium nitride hard mask reduces redeposition problems. Critical dimension control and substantially vertical sidewalls also result from the use of the titanium nitride hard mask.