FIELD-AIDED THERMAL CHEMICAL-VAPOR-DEPOSITION OF COPPER USING CU(I) ORGANOMETALLIC PRECURSOR

A de substrate bias which is not enough to make a plasma was applied d uring the chemical vapor deposition of copper to change the adsorption behavior of the reactant. Copper films were deposited on TiN and SiO2 from Cu(hfac)(tmvs) with and without the substrate bias. The surface morphology, the thickness, the sheet resistance, and the purity of the films were investigated. When a negative substrate bias of -30 V was applied to the substrate, the deposition rate of copper increased both on TiN and SiO2. The substrate bias did not cause the change in the c hemical composition of the deposited copper film. It was calculated th at Cu(hfac) has the dipole moment whose direction is from copper to hf ac. The local electric fields due to surface roughness may affect the adsorption behavior of the precursor, especially the direction of the molecular dipole moment. Resulting from the overlapping population val ue analysis, the improvement of deposition rate under negative substra te bias was explained as due to the adsorption of the copper atom in t he Cu(hfac) species directly onto the substrate by the local electric fields applied between the substrate and the gas showerhead.