Slurry, polishing solution production method, and polishing method
A slurry containing abrasive grains and a liquid medium, in which the abrasive grains include first particles and second particles in contact with the first particles, the first particles contain cerium oxide, the second particles contain a cerium compound, and an Rsp value calculated by Formula (1) below is 1.60 or more: Rsp =( Tb/Tav )−1 (1) [in the formula, Tav represents a relaxation time (unit: ms) obtained by pulsed NMR measurement of the slurry in a case where a content of the abrasive grains is 2.0% by mass, and Tb represents a relaxation time (unit: ms) obtained by pulsed NMR measurement of a supernatant solution obtained when the slurry is subjected to centrifugal separation for 50 minutes at a centrifugal acceleration of 2.36×10 5 G in a case where the content of the abrasive grains is 2.0% by mass.]
1. A slurry comprising abrasive grains and a liquid medium, wherein
the abrasive grains include first particles and second particles in contact with the first particles,
the first particles contain cerium oxide,
the second particles contain a cerium compound, and
an Rsp value calculated by Formula (1) below is 1.60 or more:
Rsp =( Tb/Tav )−1 (1)
in the formula, Tav represents a relaxation time (unit: ms) obtained by pulsed NMR measurement of the slurry in a case where a content of the abrasive grains is 2.0% by mass, and Tb represents a relaxation time (unit: ms) obtained by pulsed NMR measurement of a supernatant solution obtained when the slurry is subjected to centrifugal separation for 50 minutes at a centrifugal acceleration of 2.36×10 5 G in a case where the content of the abrasive grains is 2.0% by mass.
2. The slurry according to claim 1 , wherein the cerium compound contains cerium hydroxide.
3. The slurry according to claim 2 , wherein a content of cerium hydroxide in the abrasive grains is 3 to 50% by mass on the basis of the entire abrasive grains.
4. The slurry according to claim 2 , wherein a particle size of the second particles is 50 nm or less.
5. The slurry according to claim 1 , wherein an average particle size of the abrasive grains is 16 to 1050 nm.
6. The slurry according to claim 1 , wherein a content of the abrasive grains is 0.01 to 10% by mass.
7. The slurry according to claim 1 , wherein a particle size of the first particles is 100 nm or more.
8. The slurry according to claim 1 , wherein a particle size of the second particles is smaller than a particle size of the first particles.
9. The slurry according to claim 1 , wherein a particle size of the second particles is 30 nm or less.
10. The slurry according to claim 1 , wherein an average particle size of the abrasive grains is 120 nm or more.
11. The slurry according to claim 1 , wherein a content of cerium oxide in the abrasive grains is 50 to 97% by mass on the basis of the entire abrasive grains.
12. The slurry according to claim 1 , wherein a content of the abrasive grains is 0.01 to 5% by mass.
13. A polishing liquid obtained by filtering the slurry according to claim 1 .
14. The slurry according to claim 1 , wherein a particle size of the second particles is 50 nm or less.
15. The slurry according to claim 1 , wherein a particle size of the first particles is 100 nm or more, and a particle size of the second particles is 30 nm or less.
16. A method for producing a polishing liquid, the method comprising a step of filtering the slurry according to claim 1 .
17. A polishing method comprising a step of polishing a surface to be polished by using a polishing liquid obtained by the method for producing a polishing liquid according to claim 16 .
18. The polishing method according to claim 17 , wherein the surface to be polished contains silicon oxide.