Silatrane-Based Molecular Nanolayers as Efficient Diffusion Barriers for Cu/SiO₂/Si Heterojunctions: Implications for Integrated Circuit Manufacturing

With the rapid development of emerging technologies such as artificial intelligence and high-frequency communications, advanced subnanometer chips with a high-performance computing ability have received worldwide attention. The success of subnanometer chips relies on ultrafine pitch integrated circuit (IC) manufacturing technology and “more than Moore” three-dimensional (3D) IC packaging technology. Copper (Cu) is a key conducting material used to fabricate planar and through-silicon-via Cu/SiO₂/Si heterojunctions in 3D IC packaging architectures. The construction of an ultrathin diffusion barrier with a high film uniformity and adhesion strength at various Cu/SiO₂/Si heterojunctions is an imperative and challenging task. In this study, we demonstrate that a molecule-based nanolayer assembled from amine-terminated silatrane is a promising diffusion barrier for blocking active atomic diffusion of Cu to Si. The breakdown temperature at which Cu silicides are formed at heterojunctions is taken as an indicator of the efficacy of the molecule-based diffusion barriers. Due to their superior structural stabilities and intermolecular networking abilities, silatranes can assemble into denser and more organized molecular nanolayers than commercially available amine-terminated silanes. Benefiting from the well-organized network structure, the silatrane-based barrier increased the breakdown temperature to 500 °C, which was greater than those seen without a barrier (400 °C) or with silane-based (450 °C) barriers.