Enhanced CVD of Copper Films on Self-Assembled Monolayers as Ultrathin Diffusion Barriers

Copper films were produced by chemical vapor deposition (CVD) using the precursor Cu(II) bis-hexafluoroacetylacetonate [ Cu II ( hfac ) 2 ] on self-assembled monolayers of 3-mercaptopropyltrimethoxysilane (MPTMS)-modified substrate. X-ray diffraction and X-ray photoelectron spectroscopy results showed that the deposited copper was metal copper. The apparent activation energy of Cu CVD is changed from 80 kJ ∕ mol for the unmodified Si O 2 substrate to 69.2 kJ ∕ mol for the MPTMS-modified substrate. The growth rate on the MPTMS-modified substrate is approximately 2.2 times as much as on the unmodified one. The results indicate that the Cu CVD on MPTMS-modified Si O 2 substrate is enhanced. Moreover, Cu films which were formed on the oxidized MPTMS-self-assembled monolayer (SAM) surface ( – S O 3 H terminated) behaved with higher affinity than those deposited on the MPTMS-SAM surface, a possible reason being that the terminal groups of SAMs accelerate the protonation of ligand hfac and its desorption from the surface.