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

A nonfluorinated beta-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 degrees C. Pyrolysis of Cu(tbaoac)(2) leads to the formation of copper films at 225 degrees C, compared to 330 degrees 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 mu Ohm-cm at a thickness as low as 1300 Angstrom. A possible mechanism for the decomposition of the ligand tbaoac has been proposed.