Overcoming Ce–O–Si bonding: A pre-cleaning strategy for removing ceria particles on wafer surface after chemical mechanical polishing

<!-- START_ABSTRACT --> <p> During the chemical mechanical polishing (CMP) process, nanoparticles firmly adhere to the wafer surface through interfacial interactions under conditions of high pressure, high reactivity, and complex flow fields, resulting in the formation of contaminants that are difficult to remove. To address the challenging of ceria (CeO2) particles forming Ce–O–Si chemical bond with silicon oxide (SiO2) surfaces, which makes them difficult to desorb, this work proposes a buff cleaning strategy based on physicochemical synergy. The influences of key process parameters, including pressure, polishing head/platen rotation speed, flow rate, and cleaning time on the adsorption behavior of CeO2 particles were systematically investigated. Furthermore, the mechanisms underlying the enhanced particle removal efficacy of nonionic, anionic, and cationic surfactants were elucidated. Results indicate that the core mechanism of buff cleaning involves tuning process parameters to enhance the fluid dynamic drag (FD) favorable for particle dislodgement, thereby overcoming the interfacial adhesion forces. Cationic surfactants facilitate the conversion of Ce3+ to Ce4+ through an adsorption-oxidation synergistic mechanism. The reliability of the cleaning results was validated through nanoparticle removal experiments conducted on 12-inch wafers. This study provides insights into the control of nanoscale contaminants and lays a foundation for the optimization of semiconductor process cleaning strategies. </p> <!-- END_ABSTRACT --> <!-- START_TEMPLATE --> <ul> <li> Source: </li> <li> Tags: </li> </ul> <!-- END_TEMPLATE -->