Showa Denko K.k.

Showa Denko Kabushiki Kaisha

Hiroshi Saegusa

Tomoyuki Masuda

Katsura Ito

Fumio Imai

A cerium-based abrasive that achieves a high polishing rate and suppresses the occurrence of surface defects such as scratches and pits and the deposition of the abrasive particles on the polished surface in surface polishing of glass substrates or the like, at low cost with a high production efficiency. The cerium-based abrasive includes a cubic composite rare earth oxide and a composite rare earth oxyfluoride, containing 95.0 to 99.5 mass % of total rare earth elements in terms of oxides, containing 54.5 to 95.0 mass % of cerium in terms of oxide, 4.5 to 45.0 mass % of lanthanum in terms of oxide, and 0.5 to 2.0 mass % of neodymium in terms of oxide relative to the total rare earth elements in terms of oxides, containing 0.5 to 4.0 mass % of fluorine atoms, and containing 0.001 to 0.50 mass % of sodium atoms relative to the total rare earth elements in terms of oxides.

Cerium-based abrasive material and process for producing same

By providing an abrasive having a ratio of volume-cumulative (95%) average particle size (D95) to volume-cumulative (50%) average particle size (D50) (D95/D50) falling within a range of 1.2 to 3.0 or an abrasive having a volume-cumulative (95%) average particle size (D95) falling within a range of 0.1-1.5 &#x3bc;m and containing coarse particles having a size more than 10 times the volume-cumulative (50%) average particle size (D50) in an amount, based on the total mass of all the particles, of 1 mass % or less, there can be provided an abrasive, an abrasive slurry, a method for producing an abrasive, and a polishing method which attain, during accurate polishing of substrates such as electronics substrates, a high removal rate and a high-quality surface; i.e., a surface having a high flatness, low surface roughness, and substantially no microscratches or micropits.

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Toyoma, Japan

Hiroshi Saegusa