Regeneration of Used Oxide Slurry and Its Application to Oxide CMP

摘要

Since Chemical Mechanical Planarization(CMP) has been routinely utilized in integrated circuit(IC) fabrication, the consumption of slurry, main consumable in the CMP process, is greatly increased. The main purpose of this study was to regenerate the used oxide slurry using filters. The solid content in regenerated slurry was controlled by UF(UltraFine) filtration which extracts only solution from diluted slurry. RO(Reverse Osmosis) filtration was adapted to recover chemicals added in the original slurry formulation by rejecting pure DI water from used slurry solutions which was collected by UF filtration. The normal slurry was intentionally added in the regenerated slurry to reduce the process time and increase the life time of used slurry. The same removal rate of TEOS oxide was observed when CMP was performed using the regenerated oxide slurry. No microscratches were observed in the wafer polishing by regenerated slurry. Also, the defect density of polished wafers was decreased when polished by the regenerated slurry.