New routes toward chemical and photochemical vapor deposition of copper metal
Several types of volatile copper(I) and copper(II) complexes have been studied as precursors for chemical vapor deposition (CVD) of Cu metal films. Adducts of Cu(hfac)2 (hfacH = hexafluoroacetylacetone) with alcohols ROH (R = Me, Et, n-Pr, i-Pr, n-Bu, s-Bu, i-Bu) are self-reducing: CVD occurs by reduction of copper(II) to Cu metal, while the alcohols are oxidized to the corresponding carbonyl compounds. The best results have been obtained for Cu(hfac)2·i-PrOH (1.3 μm h-1 under N2 at 200°C, vs. 0.46 μm h-1 under H2). The adduct of CuII(hfac)2 with hydrazine is also self-reducing, leading to Cu metal formation under N2 at substrate temperatures of 140°C. Adducts with other nitrogen bases (e.g. piperidine) can be used for Cu CVD with H2 carrier gas. The copper(I) amide cluster [CuN(SiMe3)2]4 can be used for Cu CVD under H2. It is also phosphorescent, and it shows a slight lowering of the threshold substrate temperature for Cu deposition under UV irradiation; this suggests that the deposition can be photochemically induced.
Publication Source (Journal or Book title)
ACS Symposium Series
Maverick, A., James, A., Fan, H., Isovitsch, R., Stewart, M., Azene, E., & Cygan, Z. (1999). New routes toward chemical and photochemical vapor deposition of copper metal. ACS Symposium Series, 727, 100-112. https://doi.org/10.1021/bk-1999-0727.ch008