【Chinese Physics B】Deposition of Cu seed layer film by supercritical fluid deposition for advanced interconnects
writer：Zhao Bin (赵 斌), Zhao Ming-Tao (赵明涛), Zhang Yan-Fei (张艳飞) and Yang Jun-He (杨俊和)
keywords：Supercritical CO2, Cu, Seed layer
source：期刊
specific source：Chinese Physics B, 2013, 22,
Issue time：2013年
The deposition of a Cu seed layer film is investigated by supercritical fluid deposition (SCFD) using H2 as a reducing agent for Bis(2,2,6,6-tetramethyl-3,5- heptanedionato) copper in supercritical CO2 (scCO2). The effects of deposition temperature, precursor, and H2 concentration are investigated to optimize Cu deposition. Continuous metallic Cu films are deposited on Ru substrates at 190 °C when a 0.002 mol/L Cu precursor is introduced with 0.75 mol/L H2. A Cu precursor concentration higher than 0.002 mol/L is found to have negative effects on the surface qualities of Cu films. For a H2 concentration above 0.56 mol/L, the root-mean-square (RMS) roughness of a Cu film decreases as the H2 concentration increases. Finally, a 20-nm thick Cu film with a smooth surface, which is required as a seed layer in advanced interconnects, is successfully deposited at a high H2 concentration (0.75 mol/L).