A density functional theory study of chemical vapor depsotion of copper from (hfac) CuL compounds

摘要

Systematic density functional theory (DFT) calculations have been performed for ligand copper bond energies of typical copper beta -diketonate compounds used in chemical vapor deposition (CVD) of copper films. The molecules have the general formula (hfac)Cu~I-L, where hfac is hexafluoroacetylacetonate, and L represents: vinyltrimethylsilane (VTMS), trimethyl-phosphine, 2-butyne, and 1,5-cyclooctadiene. The hybrid DFT method is used with the three-parameter Becke exchange and the Lee-Yang-Parr correlation functionals (i.e., B3LYP with different levels of basis sets. Based on the results of the quantum chemistry calculations, a gas phase and surface knetic model for the chemical vapor deposition of copper from (hfac)Cu~I-VTMS is formulated. Depending upon the deposition conditions the rate determining step is either the gas phase scission of the vinyltrimethylsilane lignand from the copper compound or the surface reaction beween two adsorbed Cu(hfac) species. The predicted growth rates are in good agreement with experimental observations.