THE EFFECT OF ADDING HEXAFLUOROACETYLACETONE ON CHEMICAL-VAPOR-DEPOSITION OF COPPER USING CU(I) AND CU(II) PRECURSOR SYSTEMS

The effect of adding hexafluoroacetylacetone [H(hfac)] on the characteristics of copper chemical vapor deposition (CVD) with beta-ketonate precursors was studied. A significant difference in this effect is found for a CVD system using Cu(II) and Cu(I) precursors. In the reaction system using copper(II) bis-hexafluoroacetylacetonate (Cu(hfac)(2)) as the Cu(II) precursor, H(hfac) addition improves deposition selectivity on substrate surfaces by eliminating copper nuclei growth on the insulator. In the system using copper(I)-hexafluoroacetylacetonate trimethylvinylsilane [Cu(hfac)(tmvs)] asa Cu(I) precursor, selectivity is lost by H(hfac) addition but void formation in blanket CVD films in subquarter micron trenches has been suppressed. These results can be explained by the role of the H(hfac) species in the two deposition reactions. In the Cu(II) precursor system, H(hfac) poisons hydrogen-induced active surface sites on an insulator. In the Cu(I) system, it acts as a catalytic reagent for the disproportional reaction of Cu(hfac) and enhances nucleation at the first stage of the deposition reaction.