Abrasive material
The present invention provides an abrasive material capable of polishing difficult-to-polish silicon carbide at a high degree of surface precision. The present invention relates to an abrasive material including manganese dioxide particles having a non-needle-like shape possessing a ratio of the longitudinal axis to the transverse axis of the particles observed with a scanning electron microscope of 3.0 or less. The abrasive material is preferable if the average particle size D SEM of the longitudinal axis of the observed particles is 1.0 μm or less, and if the particle size D 50 of the volume-based cumulative fraction of 50% in laser diffraction/scattering particle size distribution measurement is 2.0 μm or less.
1. A method of polishing a substrate, comprising:
(a) providing an abrasive material comprising manganese dioxide particles having a non-needle-like shape having a longitudinal axis and a transverse axis, wherein a ratio of the longitudinal axis to the transverse axis of the particles is 3.0 or less; and
(b) polishing a substrate with said abrasive material;
wherein the substrate is polished to a surface roughness of 0.17 nm or less.
2. The method according to claim 1 , wherein the average particle size D SEM of the longitudinal axis of the manganese dioxide particles is 1.0 μm or less.
3. The method according to claim 1 , wherein the particle size D 50 of the volume-based cumulative fraction of 50% in laser diffraction/scattering particle size distribution measurement is 2.0 μm or less.
4. The method according to claim 1 , wherein specific surface area of the abrasive material is 20 m 2 /g or more.
5. The method according to claim 1 , wherein the crystal structure of manganese dioxide is of the γ-type.
6. The method according to claim 1 , wherein the crystal structure of manganese dioxide is of the β-type.
7. The method according to claim 5 , wherein the manganese dioxide particles have been formed by a dry pulverization step of dry pulverizing γ-type manganese dioxide deposited on an anode by electrolysis.
8. The method according to claim 6 , wherein the manganese dioxide particles have been formed by a heating step of heating γ-type manganese dioxide deposited on an anode by electrolysis in a hot atmosphere set at 200° C. to 600° C.; and a dry pulverization step of dry pulverizing the heated manganese dioxide.
9. The method according to claim 1 , wherein a ratio of the longitudinal axis to the transverse axis of the particles is 1.00 to 1.67.
10. The method according to claim 1 , wherein the abrasive material is in the form of a slurry.
11. The method according to claim 1 , wherein the substrate comprises silicon carbide.
12. The method according to claim 1 , wherein step (b) comprises polishing the substrate at a polishing rate of 0.07 μm/hr or more.
13. A method of polishing a substrate, comprising:
(a) providing an abrasive material comprising manganese dioxide particles having a non-needle-like shape having a longitudinal axis and a transverse axis, wherein a ratio of the longitudinal axis to the transverse axis of the particles is 3.0 or less, wherein the average particle size D SEM of the longitudinal axis of the particles is 1.0 μm or less, and wherein the particle size D 50 of the volume-based cumulative fraction of 50% in laser diffraction/scattering particle size distribution measurement is 2.0 μm or less; and
(b) polishing a substrate with said abrasive material;
wherein the manganese dioxide particles have been formed by a heating step of heating γ-type manganese dioxide deposited on an anode by electrolysis in a hot atmosphere set at 200° C. to 600° C.; and a dry pulverization step of dry pulverizing the heated manganese dioxide.
14. The method according to claim 13 , wherein the abrasive material is in the form of a slurry.
15. The method according to claim 13 , wherein the substrate comprises silicon carbide.
16. The method according to claim 13 , wherein the specific surface area of the abrasive material is 20 m 2 /g or more.
17. The method according to claim 13 , wherein a ratio of the longitudinal axis to the transverse axis of the particles is 1.00 to 1.67.
18. A method of polishing a substrate, comprising:
(a) providing an abrasive material comprising manganese dioxide particles having a non-needle-like shape having a longitudinal axis and a transverse axis, wherein a ratio of the longitudinal axis to the transverse axis of the particles is 3.0 or less; and
(b) polishing a substrate with said abrasive material;
wherein the crystal structure of manganese dioxide is of the β-type;
wherein the manganese dioxide particles have been formed by a heating step of heating γ-type manganese dioxide deposited on an anode by electrolysis in a hot atmosphere set at 200° C. to 600° C.; and a dry pulverization step of dry pulverizing the heated manganese dioxide.