A novel Cu(II) chemical vapor deposition precursor: synthesis, characterization, and chemical vapor deposition

Abstract

A nonfluorinated β-diketonate precursor, bis(t- butylacetoacetato)Cu(II) or Cu(tbaoac)₂, was synthesized by modifying bis(dipivaloylmethanato)Cu(II) or Cu(dpm)₂ for chemical vapor deposition (CVD) of copper. The complex was characterized by a variety of techniques, such as melting point determination, mass spectrometry, infrared spectroscopy, elemental analysis, thermogravimetric and differential thermal analysis, and x-ray diffraction. Cu(tbaoac)₂ has a higher sublimation rate than Cu(dpm)₂ over the temperature range 90- 150° C. Pyrolysis of Cu(tbaoac)₂ leads to the formation of copper films at 225 °C, compared to 330 °C for Cu(dpm)₂. As-deposited copper films were highly dense, mirror-bright, adhered strongly to SiO₂, and showed a resistivity of less than 2.9 μΩ-cm at a thickness as low as 1300 Å. A possible mechanism for the decomposition of the ligand tbaoac has been proposed.