HOT-WALL CHEMICAL VAPOR-DEPOSITION OF COPPER FROM COPPER(I) COMPOUNDS .2. SELECTIVE, LOW-TEMPERATURE DEPOSITION OF COPPER FROM COPPER(I) BETA-DIKETONATE COMPOUNDS, (BETA-DIKETONATE)CULN, VIA THERMALLY INDUCED DISPROPORTIONATION REACTIONS

Chemical vapor deposition of copper using (beta-diketonate)Cu(PR3)n (n = 1 and 2), (beta-diketonate)Cu(1,5-COD), and (beta-diketonate)Cu(alkyne) (where beta-diketonate = hexafluoroacetylacetonate (hfac), trifluoroacetylacetonate (tfac), and acetylacetonate (acac); R = Me and Et; 1,5-COD = 1,5-cyclooctadiene; alkyne = bis(trimethylsilyl)acetylene (BTMSA), trimethylsilylpropyne (TMSP), and 2-butyne) has been studied on Pt, W, Cu, and SiO2 substrates over the temperature range 100-400-degrees-C. Large variations in the selectivity were observed as a function of the nature of the copper ligands, substrate temperature, and nature of the substrate. In the series of compounds (hfac)Cu(PMe3), (hfac)Cu(PMe3)2, (hfac)Cu(PEt3), (hfac)Cu(PEt3)2, (hfac)Cu(1,5-COD), and (hfac)Cu(2-butyne), where the number and nature of the neutral Lewis base ligand was varied, only (hfac)Cu(PMe3) and (hfac)Cu(PEt3) exhibited selective deposition. The lowest temperature at which deposition occurred changed dramatically as a function of the number and nature of Lewis base ligands. Deposition rates as high as 1200 angstrom/min were observed under unoptimized conditions. The copper films were characterized by Auger electron spectroscopy (AES), which showed pure copper within the detection limits. Resistivities varied from 1.7 to 8-mu-OMEGA cm depending on deposition conditions. All of the compounds investigated deposited copper via the thermally induced disproportionation reaction 2(beta-diketonate)CuL(n) --> Cu + Cu(beta-diketonate)2 + 2nL. This reaction stoiochiometry was quantified for (hfac)Cu(1,5-COD) and (hfac)Cu(2-butyne) and explains the high purity of the films which results from the absence of thermally induced ligand decomposition.