title: New CVD precursors capable of depositing copper metal under mixed O2/Ar atmosphere.
abstract: Volatile low-melting CuII metal complexes Cu[OC(CF3)2CH2C(Me)=NMe]2 (4) and Cu[OC(CF3)2CH2CHMeNHMe]2 (5) were synthesized and characterized by spectroscopic methods. A single-crystal X-ray diffraction study on complex 4 shows the anticipated N2O2 square-planar geometry with the imino alcoholate ligand arranged in the all-trans orientation. In contrast, a highly distorted N2O2 geometry with a dihedral angle of 33 degrees was observed for complex 5, suggesting that the fully saturated amino alcoholate ligand produces a much greater steric congestion around the metal ion. Metal CVD experiments were conducted, showing that both complexes, 4 and 5, are capable of depositing copper metal at temperatures of 275-300 degrees C using an inert argon carrier gas mixed with low concentrations (2-8%) of O2. The best copper thin film showed a purity of approximately 96 at. % and a resistivity of 2.11 microOmega cm versus that of the bulk standard (1.7 microOmega cm), as revealed by XPS and four-point probe analyses, respectively. We speculate that the low concentration of O2 promotes partial ligand oxidation, thus releasing the reduced copper on the substrate and affording the high-purity copper deposit.
authors.affiliation: Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: Eddy
authors.initials: E
authors.lastname: Lay
authors.forename: Yi-Hwa
authors.initials: YH
authors.lastname: Song
authors.forename: Yuan-Chieh
authors.initials: YC
authors.lastname: Chiu
authors.forename: Yang-Miin
authors.initials: YM
authors.lastname: Lin
authors.forename: Yun
authors.initials: Y
authors.lastname: Chi
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Carty
authors.forename: Shie-Ming
authors.initials: SM
authors.lastname: Peng
authors.forename: Gene-Hsiang
authors.initials: GH
authors.lastname: Lee