A novel two-step MOCVD for producing thin copper films with a mixture of ethyl alcohol and water as the additive

The feasibility of using a novel metal-organic chemical vapor deposition (MOCVD) technique to achieve the deposition of a smooth, continuous, and conformal copper (Cu) film on the TaN substrate was examined. This method consists of two consecutive steps: an oxide deposition step followed by a reduction step. In the oxide deposition step, cuprous oxide (Cu2O) is deposited with Copper(II)-1,1,1,5,5,5-hexafluoroacetylacetonate hydrate (Cu(hfac)2·xH2O) as the precursor and a mixture of ethyl alcohol and water as the additive. In the reduction step, the preformed Cu2O thin film is reduced to an elemental copper metal film through exposure to ethyl alcohol. Experimental results indicate that the proposed two-step MOCVD method succeeds in forming smooth, continuous, and conformal copper films. The grain size and roughness of these copper films are ranging from 30 to 94 nm and from 1.12 to 6.33 nm, respectively. Therefore, this technique may potentially be used as high-quality seed layers for electroplating.