Enhancing copper interconnect reliability with self-assembled monolayer 1-(3-Aminopropyl)silatrane as diffusion barrier layer: A computational study

With the advancement of integrated circuit technology towards smaller dimensions and higher performance, the issue of copper interconnect diffusion has emerged as a critical factor limiting their reliability. To enhance the reliability of copper interconnects, this study focuses on the innovative diffusion barrier material, self-assembled monolayer (SAM) 1-(3-aminopropyl)silazane (APS). By integrating density functional theory calculations with molecular dynamics simulations, an in-depth investigation is conducted into the adsorption behavior of APS on the SiO₂ surface, the formation mechanism of SAM, and the microstructure and properties of the Si/SiO₂/SAM-APS/Cu interface. The research demonstrates that APS molecules form strong chemical interactions with the SiO₂ surface via amino groups and can stably assemble into a monolayer on the SiO₂ surface, exhibiting a significant diffusion barrier effect. Particularly under high-temperature conditions, the SAM-APS layer maintains excellent thermal stability and a robust diffusion barrier capacity. Furthermore, the APS SAM configuration induces a distinct band structure at the interface, effectively inhibiting the diffusion of electrons and metal ions and enhancing the stability of the interface. Simulation results indicate that the SAM-APS layer achieves a diffusion barrier height exceeding 11.35 eV at the SiO₂/Cu interface, highlighting its exceptional application potential. This study introduces novel concepts for the design of diffusion barrier layers in copper interconnect technology and provides a scientific foundation for the development of high-performance and high-reliability microelectronic devices. Future research will focus on further optimizing the performance of SAM-APS and exploring its application potential in more complex microelectronic systems.