Electroless deposition and electrical resistivity of sub-100nm Cu films on SAMs: State of the art

Self-assembled organic monolayers (SAMs) of silanes with -SH, -NH"2 and -C"5H"4N functional groups have been shown recently to act as ultra-thin, robust diffusion barriers at the Cu/SiO"2 and Cu/ultra low-k dielectric interfaces. More generally, SAMs with their tunable surface chemistry are essential elements of future all-wet ULSI metallization with Cu deposited by electroless (ELD) over SAM-functionalized dielectrics. Far too small is known however on the electrical properties of thin metal films formed onto SAM/dielectric substrates. In this paper, we give first a brief literature survey of what is known about Cu films deposited by electroless over dielectrics modified by SAMs. Second, we present our observations of electrical resistivity @r of sub-100nm ELD Cu films deposited over the surface of amino-silane SAM/SiO"2 activated by Au monodispersed nano-particles and show that this techniques helps to obtain considerably smaller @r compared to the previously reported data.

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