The adhesion of copper films deposited onto aluminum nitride

Good adhesion between copper film and AIN substrate is obtained when the su rface of AIN is laser-irradiated prior to copper film deposition and post d eposition annealing is conducted. Surface chemistry of AIN substrates befor e and after laser irradiation and the interfacial reactions of copper film/ AIN couples were studied with Auger Electron Spectroscopy (AES) to understa nd the adhesion mechanisms. The surface of as-received AIN substrates was c overed with a thin sheath of Al2O3 Laser irradiation removed the surface Al 2O3 layers, smoothened the surface, and decomposed AIN leaving metallic alu minum on the surface. The interfacial reactions in the copper film/AIN coup le are affected by the amounts of oxygen and metallic aluminum available at the interface. The adhesion mechanism is the formation of a Cu-O-Al compou nd at the interface of copper film/AIN couple. Since copper does not react with AIN, laser induced decomposition of AIN seems to be the driving force for the formation of the compound. (C) 1999 Kluwer Academic Publishers.