Structural characterization of a manganese oxide barrier layer formed by chemical vapor deposition for advanced interconnects application on SiOC dielectric substrates

We investigated the microstructure and growth behavior of a manganese oxide layer deposited on SiOC substrates for the purpose of providing a new method to form a thin diffusion barrier layer for advanced LSI interconnections. The Mn oxide layer was formed by chemical vapor deposition (CVD), using bis(ethylcyclopentadienyl)Mn as a precursor and H₂ as a carrier gas at 300 C for 30 min. The Mn oxide layer could be formed on plasma-treated SiOC, but not on as-received SiOC. By using thermal desorption spectroscopy (TDS), moisture absorption in SiOC was evidenced after plasma treatment, using various gases of O₂, N₂, and Ar. Two adsorbed moisture components, physisorbed (α) and chemisorbed (β, γ), were observed which were responsible for the formation of crystalline MnO_x and amorphous MnSi_xO_y, respectively. The position of the Mn oxide layer was also investigated by measuring the variation of the SiOC thickness. The Mn oxide layer was formed within the SiOC substrate. The result indicates that the Mn oxide barrier layer would have no influence on the line resistance value, but influences on the dielectric capacitance value.