Perspective—Recent Advances and Thoughts on Ceria Particle Applications in Chemical Mechanical Planarization

Abstract

Along with the remarkable growth in the complexity of semiconductor fabrication technology, chemical mechanical planarization (CMP) has evolved and become progressively more sophisticated over the years, enabling the implementation of novel integration schemes. This paper discusses current research and development trends in one specific aspect of the CMP technology, namely, ceria particle usage for advanced technology nodes and provides some perspectives on how to improve CMP performance metrics of the current ceria abrasives and ceria-based CMP slurries and move forward to the next phase.

Investigation of Polisher Head and Slurry Sweep Effect in Oxide Film Polishing

“…14 Mechanical milling, filtration, and static settlement processes are employed to disperse the particles into uniform-sized abrasive distributions. 15,16 The control of surface Ce 3+ ratio in ceria abrasives is beneficial in improving oxide polishing. [17][18][19] Throughout the polishing process, mechanical abrasion plays a crucial role in the tribochemical reaction for the formation and subsequent breakage of Ce-O-Si bonds.…”

Environmental Impact Assessment of Chemical Mechanical Planarization Consumables: Challenges, Future Needs, and Perspectives

“…40 Additionally, the wet synthesis method for producing ceria abrasives, particularly using ammonium cerium nitrate, results in the generation of substantial amounts of nitrate ions, along with the production of significant amounts of wastewater during the multiple washing cycles required in the process. 32,39,41 These ions are problematic as they contribute to human health risks along with the eutrophication of natural environments. 42−44 While these wet synthesis methods are more energy-efficient compared to calcination, operating at lower temperatures, they still pose environmental challenges.…”

“…During ball milling and separation processes, abrasive particles are subjected to narrow size distribution, hence the undesired particles and waste compounds will be washed away and removed. 32 This would likely cause human exposure to the nanoparticles potentially causing human health effects as well as generation of wastewater. 56 As discussed in the SNO workshop, biological studies on nanoceria exhibit significant variability and conflicting outcomes, hence scientific community still trying to understand the conditions that may cause adverse outcomes.…”

Effects of Gas-Dissolved Water for Ceria Nanoparticles on the SiO2 Film Surface in Post-CMP Cleaning

“…The use of smaller CNPs is the preferred to achieve defect-free surfaces. 2,3 As the trend towards using colloidal and smaller CNPs continues, challenges in post-CMP cleaning for the removal of residual CNPs on SiO 2 film surface have become more pronounced. 4 Higher Ce 3+ concentration at the surfaces of smaller CNPs can lead to the formation of more Ce-O-Si bonds with SiO 2 film surface, requiring relatively higher energy for rupture compared to other bonds (e.g., Si-O).…”