(596e) Selective Atomic Layer Deposition of Zirconia on Electroplated Copper Substrates
The ceramic material zirconia has numerous applications in the biomedical, electronics and nanofabrication industries because of its high dielectric constant, chemical stability and high wear resistance. In this study, zirconium oxide was selectively deposited on silicon (100) substrates in the presence of both silicon and electrolytically plated copper substrates through atomic layer deposition. Compared to electron beam evaporated copper, electrolytically plated copper is more suitable for large scale manufacturing and for use as interconnects in integrated circuits. Therefore selective atomic layer deposition on copper may be of interest as a gate dielectric for the next generation of integrated circuits. Atomic layer deposition was performed with tris(dimethylamino)cyclopentadienyl zirconium as the zirconium precursor and ethanol as the co-reactant in a custom made ALD system (Patent #10214817). Ethanol supplied from an ice-bath served as an oxidizer for the zirconium precursor and as a reducer for the copper substrate. Selectivity was absolute for up to 70 ALD cycles and further selectivity could be achieved through alteration of the pretreatment process and the ALD recipe. Selectivity seemed to depend on the chemical species present on copper surface and byproducts formed due to adsorption of ethanol on the surface.