Properties of tungsten thin film deposited using inductively coupled plasma assisted sputtering for next-generation interconnect metal

摘要

Tungsten (W) is actively investigated as one of the future metallization materials which can replace Cu for the metal thickness lower than tens of nanometer due to its sfmall electron mean free path of 19 nm and high melting temperature of 3673 K. In this study, inductively coupled plasma (ICP) assisted DC magnetron sputtering of W has been investigated for the lower resistivity of nm scale W film (30 nm). When the characteristics of W thin films deposited with and without ICP assistance were investigated, the decrease of the W thin film resistivity with the increase of deposition rate was observed as the ICP power is increased regardless of substrate heating. The decrease of W thin film resistivity by the ICP assisted DC sputter deposition was related to the change of crystal structure from A-15 to BCC, decreased oxygen incorporation in the film, decreased surface roughness, and increased grain size due to the increased ion flux to the substrate.