Plasma-enhanced atomic layer deposition of Cu–Mn films with formation of a MnSixOy barrier layer

Conformal Cu–Mn seed layers were deposited by plasma enhanced atomic layer deposition (PEALD) at low temperature (120°C), and the Mn content in the Cu–Mn alloys were controlled form 0 to approximately 10 atomic percent with various Mn precursor feeding times. Resistivity of the Cu–Mn alloy films decreased by annealing due to out-diffusion of Mn atoms. Out-diffused Mn atoms were segregated to the surface of the film and interface between a Cu–Mn alloy and SiO2, resulting in self-formed MnOx and MnSixOy, respectively. The adhesion between Cu and SiO2 was enhanced by the formation of MnSixOy. Continuous and conductive Cu–Mn seed layers were deposited with PEALD into 24nm SiO2 trench, enabling a low temperature process, and the trench was perfectly filled using electrochemical plating under conventional conditions.