Theoretical screening of precursors for selective atomic layer deposition on Cu/SiO₂ surface

Selective atomic layer deposition(ALD) exhibits significant advantages in the fabrication of nanoscale materials, fundamentally leveraging the differential reaction rates of precursors across distinct regions. This study focuses on the deposition process alignment of dielectric materials in semiconductor interconnects and back-end processes. Using density functional theory (DFT) combined with micro-dynamics analysis, we elucidate the adsorption and decomposition mechanisms of the precursors. By further integrating these insights with ALD process conditions, we achieved a quantitative description of the reaction rates and coverages of precursors on Cu/SiO₂ surfaces. The selectivity of ten Al/Si precursors was screened based on the coverage discrepancy between the two surfaces. Results indicate that the adsorption energies on Cu surfaces range from −0.62 eV to −1.70 eV, whereas on SiO₂ surfaces, they range from −0.31 eV to −0.93 eV. For the majority of the precursors, the reaction energy barriers on Cu surfaces are lower than those on SiO₂ surfaces. Notably, DMAI exhibits a lower reaction energy barrier on SiO₂ surfaces. The coverage ratio of DMAI on SiO₂ to Cu is 2.63×10⁸, TEA and BEMAS demonstrate comparable coverage on both SiO₂ and Cu surfaces, indicating their potential for selective deposition on SiO₂. This study provides theoretical guidance for the experimental selection of precursors.