Method of fabricating metal-bearing integrated circuit structures having low defect density

Abstract

A method of fabricating metal-bearing structures in an integrated circuit such as metal-polysilicon capacitors using conductive metal compounds. Defects due to organometallic polymers formed during the etch of a hard mask material are minimized by using a process that includes a plasma etch for the hard mask that achieves a predominantly chemical character using a fluorine-based etch chemistry. Using a low-temperature liquid-phase strip of the hard mask photoresist instead of an ash prevents further cross-linking of polymers formed during the plasma etch. Etching the metal-bearing material using a hot fully-concentrated mixture of ammonium hydroxide and hydrogen peroxide allows short etch times that are particularly shortened for tantalum nitride films deposited with a nitrogen concentration of about 30 percent or greater.