Formation of Al xO yN z barriers for advanced silver metallization

Y. Wang, Terry Alford

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Silver has been explored as a potential candidate for future advanced interconnects due to its lowest electrical resistivity, when compared with Al and Cu. As in the case of Cu metallization, an additional layer between the Ag film and underneath dielectric is necessary in order to improve adhesion and to block the diffusion of Ag atoms. In this study, thin aluminum oxynitride (Al xO yN z) diffusion barriers have been formed in the temperature range of 400-725 °C by annealing Ag/Al bilayers on oxidized Si substrates in ammonia ambient. Rutherford backscattering spectrometry showed that the out-diffused Al reacted with both the ammonia and oxygen in the ambient and encapsulated the Ag films, Higher process temperatures and thinner original Al layers showed to improve the resistivity of the encapsulated Ag layers. The resulting Ag resistivity values are ∼1.75 ± 0.35 μΩ-cm. The thermal stability test of these diffusion barriers showed that these barriers sustained the interdiffusion between Cu and Ag up to 620 °C at least for 30 min in either vacuum or flowing He-0.5% H 2. This temperature is a 200°C improvement over previously reported values for the self-encapsulated Cu and Ag films. X-ray diffraction spectra showed no formation of any high resistive intermetallic compounds, i.e., Ag 3Al, Ag 2Al, and AlAg 3.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium - Proceedings
EditorsG.S. Oehrlein, K. Maex, Y.-C. Joo, S. Ogawa, J.T. Wetzel
StatePublished - 2000
EventMaterials, Technology and Reliability for Advanced Interconnetcs and Low-K Dielectrics - San Francisco, CA, United States
Duration: Apr 23 2000Apr 27 2000


OtherMaterials, Technology and Reliability for Advanced Interconnetcs and Low-K Dielectrics
Country/TerritoryUnited States
CitySan Francisco, CA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials


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