Patent ID: 6537907
Filing Date: 2003-03-25
Classification: H01L

Abstract:
A method of forming a composite metal interconnect structure comprised of an overlying aluminum based structure on an underlying titanium nitride shape, wherein an aluminum fluoride layer formed on the sides and on the top of said underlying titanium nitride shape is used as an etch mask for definition of said underlying titanium nitride shape, comprising the steps of:depositing a titanium nitride layer; depositing an aluminum based layer on said titanium nitride layer; applying an anti-reflective coating, (ARC), layer, on said aluminum based layer; forming a narrow width, photoresist shape on said ARC layer; performing a first dry etching step of a two step dry etching procedure in a first dry etching environment comprised with a chlorine containing etchant, using said photoresist shape to define said aluminum based structure on said titanium nitride layer; removing said narrow width, photoresist shape, and said ARC layer; and performing a second dry etching procedure of said two step dry etching procedure in a second dry etching environment comprised with said chlorine containing etchant and comprised with a fluorine containing etchant, forming said aluminum fluoride layer on the top surface and on the sides of said aluminum based structure, while simultaneously defining said underlying titanium nitride shape using said aluminum based structure, comprised with a top surface covered by said aluminum fluoride layer, as an etch mask.