Mechanisms and Development of Ceria-Based, Fast Oxide Slurries

Abstract

Recent developments in vertical integration schemes including 3D-NAND flash memory have introduced a significant need for fast oxide slurries (1). Specifically, the new staircase CMP process requires exceptionally large step heights to be polished in a timely manner. Balancing low defectivity and high planarization efficiency with extremely fast bulk oxide removal rates is a difficult but crucial set of requirements. Ceria-based slurries with fine-tuned chemistries are well suited to meet these challenges. Mechanisms for ceria-based slurries polishing behavior on oxide surfaces have been the subject of investigation for a number of years now. A careful examination of these proposed mechanisms can drive the design and development of next generation fast oxide slurries.