Novel PEALD-Ru formation technique using H2 & H2/N2 plasma as a seed layer for direct CVD-Cu filling

Abstract

In this paper, novel Ru film formation technique by plasma enhanced atomic layer deposition (PEALD) is reported to be extremely promising as a seed layer for direct CVD-Cu full filling. PEALD-Ru film property can be controlled by H2 to N2 gas flow ratio in plasma step. PEALD-Ru film using H2/N2 mixed gas based plasma can provide low resistivity (20µΩ-cm), sufficient Cu barrier property and 100% step-coverage. PEALD-Ru film using H2 gas based plasma can provide (002) oriented Ru film, which is confirmed as good nucleation layer for CVD-Cu formation. Stacked film of Ru(H2)/ Ru(H2/N2) is demonstrated to be attractive as an underneath for direct CVD-Cu full filling without void generation in 50 nm via pattern.