Hot-Wall Chemical Vapor Deposition of Copper From Copper (I) Compounds. II. Selective, Low--Temperature Deposition of Copper From Copper (I) beta -Diketonate Compounds, ( beta -diketonate)CuL sub n , via Thermally Induced Disproportionation Reactions

• Published in: Chemistry of materials 1992-07, Vol.4 (4), p.788-795
• Main Authors: Shin, H K, Chi, K M, Hampden-Smith, M J, Kodas, T T, Farr, J D, Paffett, M
• Format: Article
• Language: English
• ISSN: 0897-4756

Chemical vapor deposition of copper using ( beta -diketonate Cu(PR sub 3 ) sub n (n = 1 and 2), ( beta -diketonate)Cu-(1,5)-COD), and ( beta -diketonate)Cu(Alkyne) (where beta -diketonate = hexafluoroacetylacetonate (hfac), trifluoroacetylacetonte (hfac), and acetylacetonate (acac); R = Me and Et; 1,5-COD = 1,5-cyclooctadiene; alkyne - bis(trimethylsily)acetylene (BTMSA), trimethylsilylpropyne (TMSP), and 2-butyne)-- has been studied on platinum, tungsten, copper, and SiO sub 2 substrates over the temperature range 100-400 deg C. Large variations in the selectivity were observed as a function of the nature of the Cu ligands, substrate temperature, and the nature of the substrate. In the series of compounds (hfac)Cu(PMe sub 3 ), (hfac)Cu()PMe sub 3 ) sub 2 , (hfac)Cu(PEt sub 3 ), (hfac)Cu(PEt sub 3 ) sub 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(PMe sub 3 ) and (hfac)Cu(PEt sub 3 ) 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 A /min were observed under unoptimized conditions. The Cu films were characterized by Auger electron spectroscopy (AES), which showed pure Cu within the detection limits. Resistivities varied from 1.7-8 mu Omega cm depending on deposition conditions. All of the compounds investigated deposited Cu via the thermally induced disproportionation reaction 2( beta -diketonate)CuL sub n - > Cu + Cu( beta -diketonate) sub 2 + 2nL. This reaction stoichiometry 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.