Utilization of Sonochemical Energy for Post-Chemical Mechanical Planarization Substrate Cleaning

For the demands of future technology to be achieved, the size of integrated circuits must decrease. This requires surfaces with minimal defects to enable the stacking of each substrate layer without hinderance to performance. To create atomically flat surfaces for these circuits, the process of Chemical Mechanical Planarization must utilize aggressive processing conditions, which produces primary defects (i.e., nanoparticle residue) which must then be removed in a cleaning step. While these defects are traditionally removed through mechanical scrubbing with a polyvinyl alcohol brush (PVA), this induces irremovable secondary defects (i.e., scratching, pitting). To reduce secondary defects and still promote high particle removal efficiency (PRE), an alternative method of cleaning utilizes megasonic energy to sonochemically remove particles through high energy cavitations. This work explores the application of megasonic energy to remove defects from two different types of substrates: tetraethyl ortho silicate (TEOS) and silicon carbide (SiC). For both, the cavitations serve both to cleave the bond between nanoparticle and substate while also reducing the stern layer of the substrate, enabling the transfer of cleaning chemistry to the interface for further residue interaction.