Effects of amino-terminated self-assembled monolayers on nucleation and growth of chemical vapor-deposited copper films

Copper films were grown on clean Si, SiO2 and 3-amino-propyl-trimethoxy-silane (APTMS) self-assembled monolayers (SAMs)-modified SiO2 substrates via chemical vapor deposition (CVD) and were examined using scanning electron microscopy, atomic force microscopy, and X-ray diffraction (XRD). Ordered APTMS-SAMs obtained from a 3 mM concentration solution were found to enhance adhesion of the films on the SiO2 substrate surface. However, in 60 mM solution, APTMS layers tended to be multilayered and formed islands via self-polymerization. Copper nucleation on APTMS-SAMs modified substrate surfaces occurs more easily than on the clean Si and SiO2 substrate surfaces. Enhanced copper CVD was ascribed to the interaction of Cu atoms with the N-containing terminal groups of APTMS-SAMs. The XRD analysis showed that the copper thin films deposited on the APTMS-modified SiO2 substrates have a structure with (111) preferred orientation, which is known to have a good electromigration resistance.