Copper(I) precursors for chemical vapor deposition of copper metal

Several copper(I) complexes are compared as precursors for deposition of Cu metal from the vapor phase in H2carrier gas. The best of these, (hfacJCu1COD) (hfacH = l, l, l, 5, 5, 5-hexafluoro-2, 4-pentanedione; COD = 1, 5-cyclooctadiene), yields films of low resistivity (3-4 µΩ cm) and high purity (96%, by Auger electron spectroscopy); these are similar to films produced by H2reduction of the more familiar copper(II) complex Cu(hfac)2. (Hfac)CuI(1, 3-butadiene) and [(hfac)CuI]2(µ-l, 3, 5, 7-cyclooctatetraene) produce films of only slightly higher resistivity (4-6 µΩ cm), but films from CpCuI(PR3) (R = CH2CH3, OCH3, OCH2CH3) are noticeably inferior (ρ 10 µΩ cm). (hfac)CuI(COD) has also been studied by X-ray crystallography. (Hfac)CuICOD), monoclinic, space group P21/c; a = 10.042 (2), b = 9.878 (2), c = 15.756 (3) Å β = 108.64 (2)° Z = 4; R = 0.044 (Rw= 0.051) for 1790 reflections (I 3σ(D) and 233 parameters. The structure contains a 2-fold disorder in the Cu atom position, corresponding to n2and n4bonding modes of the COD ligand.