Aqueous cerium oxide dispersion
View Patent ↗Aqueous cerium oxide dispersion Aqueous cerium oxide dispersion, containing 5 to 60% by weight cerium oxide. It can be used to polish SiO 2 in the semiconductor industry.
1. An aqueous cerium oxide dispersion, consisting of 5 to 60% by weight cerium oxide, including aggregate particles with a particle size distribution of
d50<120 nm
d99<200 nm
in water, which has a pH of 3 to 8 and a viscosity of less than 30 mPas.
2. A process for polishing comprising polishing SiO 2 or Si 3 N 4 with the cerium oxide dispersion according to claim 1 .
3. The process for polishing SiO 2 or Si 3 N 4 according to claim 2 , which comprises polishing until reaching an end point which is determined by a drop in motor current.
4. A process for producing the cerium oxide dispersion according to claim 1 , comprising dispersing cerium oxide powder in water.
5. The aqueous cerium oxide dispersion of claim 1 , wherein the dispersion does not contain any dispersants or additives which increase the selectivity of SiO 2 over Si 3 N 4 in Shallow Trench Isolation (STI) Chemical-Mechanical Planarizing (CMP) processing.