Chemical vapor deposition of copper via disproportionation of hexafluoroacetylacetonato(1,5 -cyclooctadiene)copper(I), (hfac)Cu(1,5-COD)

Hot- and cold-wall chemical vapor deposition (CVD) using the volatile copper(I) compound (hfac)Cu(1,5-COD), where hfac = 1,1,1,5,5,5,-hexafluoroacetylacetonate and 1,5-COD = 1,5-cyclooctadiene, as a precursor was carried out in hot-wall and warm-wall, lamp-heated reactors using SiO₂ substrates that had been patterned with Pt or W, over a temperature range 120 °C-250 °C. Deposition was observed onto Pt, W, and SiO₂ over this temperature range at rates of up to 3750 Å/min to give copper films that contained no detectable impurities by Auger electron spectroscopy and gave resistivities of 1.9-5.7 μ ohm cm. The volatile by-products formed during deposition were 1,5-COD and Cu(hfac)₂ and a mass balance was consistent with the quantitative disproportionation reaction: 2(hfac)Cu(1,5-COD) → Cu + Cu(hfac)₂ + 2(1,5-COD). The measured activation energy for this CVD reaction was 26(2) kcal/mol. The absence of selectivity for metal surfaces in the presence of SiO₂ is in contrast to CVD results for the related compounds (β-diketonate)Cu(PMe₃) where β-diketonate = hfac, 1,1,1-trifluoroacetylacetonate (tfac), and acetylacetonate (acac).