Strategic Design of Sono-Activated Nanodispersion Systems for Enhanced Chemical Mechanical Planarization (CMP)

The miniaturization of integrated circuits (ICs) and semiconductor components continues according to Moore's law, necessitating innovative processes to progress technology beyond the <3nm node. Chemical Mechanical Planarization (CMP) is an essential process for advanced semiconductor fabrication, yet conventional methods are lacking due to inefficiency and induced defectivity. This work explores the design of a flow-through megasonic system for the enhanced polishing performance of both metal and oxide substrates, leveraging acoustic cavitation to generate reactive oxygen species (ROS). These radical species modulate interfacial chemical physics, impacting both nanoparticle surface reactivity and the three-body (slurry-pad-substrate) interactions. For the front-end-of line (FEOL) process of Shallow Trench Isolation (STI) CMP, megasonics accelerate ceria (Ce³⁺/Ce⁴⁺) redox cycling via ROS-mediated charge transfer, enhancing slurry reactivity. In back-end-of-line (BEOL) processes such as Cu CMP, ROS facilitate controlled surface oxidation, enabling higher material removal rates at reduced frictional forces. ROS species are quantized through kinetic analysis of probe molecule degradation, correlating with improved polish rates and surface quality. This study focuses on the role of megasonic processing parameters (i.e., flux density, power, transducer frequency) in enhancing redox-active CMP systems.