Good adhesion between copper film and AIN substrate is obtained when the surface of AIN is laser-irradiated prior to copper film deposition and post deposition annealing is conducted. Surface chemistry of AIN substrates before and after laser irradiation and the interfacial reactions of copper film/AIN couples were studied with Auger Electron Spectroscopy (AES) to understand the adhesion mechanisms. The surface of as-received AIN substrates was covered with a thin sheath of Al2O3 Laser irradiation removed the surface Al2O3 layers, smoothened the surface, and decomposed AIN leaving metallic aluminum on the surface. The interfacial reactions in the copper film/AIN couple 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 compound 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.