Degradation of the deposition blocking layer during area-selective plasma-enhanced atomic layer deposition of Cobalt

The effects of plasma on the degradation of the deposition blocking layer during area-selective atomic layer deposition were investigated. Co atomic layer deposition (ALD) processes were developed by using Co(iPr-AMD)₂ (bis(N,N'-diisopropylacetamidinato)cobalt(II)) as a precursor, and two different reactants, NH₃ gas for thermal ALD (TH-ALD) and NH₃ plasma for plasma-enhanced ALD (PE-ALD). TH- and PE-ALD were applied to area selective ALD (AS-ALD) by using an octadecyltrichlorosilane (OTS) self-assembled monolayer (SAM) as a blocking layer. Both ALD processes produced pure Co films with resistivities as low as 50 μΩcm. For PE-ALD, however, no selective deposition was achieved due to a degradation of the OTS hydrophobicity caused by the NH₃ plasma exposure. The effects of the plasma on the blocking efficiency of SAM were studied.