H assisted control of quality and conformality in Cu film deposition using plasma CVD method

Hydrogen assisted plasma CVD (HAPCVD), in which Cu(hfac)₂ is supplied as the source material, realizes control of quality and conformality in Cu fill deposition, since H irradiation is effective in purifying the Cu films, increasing the grain size, and reducing the surface roughness, while decrease in dissociation degree of Cu(hfac)₂ leads to realize conformal deposition in fine trenches. Cu(hfac) is identified as the radical mainly contributing to the deposition. Based on the results, we propose a model in which Cu(hfac) and H react on surfaces to deposit Cu films. We also have demonstrated conformal deposition of smooth Cu films of 30 nm in thickness and 1.9 μΩcm in resistivity in trenches using the HAPCVD.