Ceria composite particle dispersion, method for producing same, and polishing abrasive grain dispersion comprising ceria composite particle dispersion

Patent metadata

Field	Value
Publication number	US-10920120-B2
Application number	US-201716342415-A
Country	US
Kind code	B2
Filing date	Oct 6, 2017
Priority date	Nov 14, 2016
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

A ceria composite particle dispersion has ceria composite particles having an average particle size of 50 to 350 nm and having the features described below. Each ceria composite particle has a mother particle, a cerium-containing silica layer on the surface thereof, and child particles dispersed inside the cerium-containing silica layer, the mother particles being amorphous silica-based and the child particles being crystalline ceria-based. The child particles have a coefficient of variation (CV value) in a particle size distribution of 14 to 40%. The ceria composite particles have a mass ratio of silica to ceria of 100:11-316. Only the crystal phase of ceria is detected when the ceria composite particles are subjected to X-ray diffraction. The average crystallite size of the crystalline ceria measured by subjecting the ceria composite particles to X-ray diffraction is 10 to 25 nm.

First claim

The invention claimed is:

1. A ceria-based composite fine particle dispersion comprising ceria-based composite fine particles having an average particle size of 50 to 350 nm and having characteristic features of [1] to [5]:
[1] each of the ceria-based composite fine particles comprises a mother particle having a core particle, a cerium-containing silica layer on a surface of the mother particle, and child particles dispersed inside the cerium-containing silica layer but with at least some amount of the child particles having portions of the surfaces thereof exposed to outside of the cerium-containing silica layer of the composite fine particle, the core particle is primarily composed of amorphous silica, and the child particles are primarily composed of crystalline ceria;
[2] the child particles have a coefficient of variation (CV value) of 14 to 40% in their particle size distribution;
[3] the ceria-based composite fine particles have a mass ratio between silica and ceria of 100:11 to 316;
[4] only a ceria crystal phase is detected when the ceria-based composite fine particles are subjected to X-ray diffractometry; and
[5] an average crystallite size of the crystalline ceria, as measured by subjecting the ceria-based composite fine particles to X-ray diffractometry, is 10 to 25 nm.

2. The ceria-based composite fine particle dispersion according to claim 1 comprising the ceria-based composite fine particles further having a characteristic feature of [6]:
[6] silicon atoms enter into solid solution in the crystalline ceria included in the child particles.

3. The ceria-based composite fine particle dispersion according to claim 2 , wherein as for cerium atoms and silicon atoms included in the child particles, a relationship of R 1 <R 2 (where R 1 is a distance between cerium and silicon atoms, and R 2 is a distance between cerium atoms) is satisfied.

4. The ceria-based composite fine particle dispersion according to claim 1 , wherein the ceria-based composite fine particles include coarse particles having a size of 0.51 μm or more, whose number measured on dry basis is 100,000,000 particles/cc or less.

5. The ceria-based composite fine particle dispersion according to claim 1 , wherein impurities are contained in the ceria-based composite fine particles in amounts shown in (a) and (b):
(a) Na, Ag, Al, Ca, Cr, Cu, Fe, K, Mg, Ni, Ti, and Zn are contained in amounts of 100 ppm or less, respectively; and
(b) U, Th, Cl, NO 3 , SO 4 , and F are contained in amounts of 5 ppm or less, respectively.

6. The ceria-based composite fine particle dispersion according to claim 1 , wherein the mother particle has the core particle and projections on its surface, the projections are primarily composed of silica, and the projections have a width of 5 to 25 nm and a height of 5 to 25 nm.

7. The ceria-based composite fine particle dispersion according to claim 6 , wherein each of the projections contained in the mother particle has a width of 5 to 25 nm.

8. The ceria-based composite fine particle dispersion according to claim 1 , wherein when cation colloidal titration is performed, a streaming potential curve in which a ratio (ΔPCD/V) between an amount of streaming potential change (ΔPCD) and an amount of cation colloidal titrant added at a knick (V) as expressed by formula (1) is in a range of −110.0 to −15.0 is obtained:
Δ PCD/V =( I−C )/ V   formula (1)

C: streaming potential (mV) at the knick
I: streaming potential (mV) at a starting point of the streaming potential curve; and
V: amount of the cation colloidal titrant added at the knick (ml).

9. A polishing abrasive grain dispersion comprising the ceria-based composite fine particle dispersion according to claim 1 .

10. The polishing abrasive grain dispersion according to claim 9 , wherein the polishing abrasive grain dispersion is used for flattening a semiconductor substrate having a silica film formed thereon.

11. A method of manufacturing a ceria-based composite fine particle dispersion comprising Steps 1 to 3:
Step 1: a step which comprises stirring a silica-based fine particle dispersion containing silica-based fine particles dispersed in a solvent; and continuously or discontinuously adding a cerium metal salt while keeping a temperature at 0 to 20° C., a pH at 7.0 to 9.0 and an oxidation-reduction potential at 50 to 500 mV, respectively, thereby obtaining a precursor particle dispersion containing precursor particles;
Step 2: a step which comprises drying the precursor particle dispersion; burning the dried precursor particle dispersion at 950 to 1,200° C. to obtain a burned body; and subjecting the resulting burned body to wet grinding at a pH of 8.6 to 10.8 after addition of a solvent to the burned body, thereby obtaining a dispersion including a burned and ground body: and Step 3: a step which comprises subjecting the dispersion including the burned and ground body to centrifugation at a relative centrifugal acceleration of 300 G or more; and subsequently removing precipitated components to obtain the ceria-based composite fine particle dispersion.

12. The method of manufacturing the ceria-based composite fine particle dispersion according to claim 11 , wherein Step 1 is a step which comprises stirring the silica-based fine particle dispersion; continuously or discontinuously adding the cerium metal salt while keeping the temperature at 0 to 20° C., the pH at 7.0 to 9.0 and the oxidation-reduction potential at 50 to 500 mV, respectively; and thereafter continuously or discontinuously adding the cerium metal salt while keeping the temperature at 20° C. or more but 98° C. or less, the pH at 7.0 to 9.0 and the oxidation-reduction potential at 50 to 500 mV, respectively, thereby obtaining the precursor particle dispersion.

13. The method of manufacturing the ceria-based composite fine particle dispersion according to claim 11 , wherein Step 1 is a step which comprises stirring the silica-based fine particle dispersion; continuously or discontinuously adding the cerium metal salt while keeping the temperature at 20° C. or more but 98° C. or less, the pH at 7.0 to 9.0 and the oxidation-reduction potential at 50 to 500 mV, respectively; and thereafter continuously or discontinuously adding the cerium metal salt while keeping the temperature at 0 to 20° C., the pH at 7.0 to 9.0 and the oxidation-reduction potential at 50 to 500 mV, respectively, thereby obtaining the precursor particle dispersion.

14. The method of manufacturing the ceria-based composite fine particle dispersion according to claim 11 , wherein impurities are contained in the silica-based fine particles in Step 1 in amounts shown in (a) and (b):
(a) Na, Ag, Al, Ca, Cr, Cu, Fe, K, Mg, Ni, Ti, and Zn are contained in amounts of 100 ppm or less, respectively; and
(b) U, Th, Cl, NO 3 , SO 4 , and F are contained in amounts of 5 ppm or less, respectively.

15. The method of manufacturing the ceria-based composite fine particle dispersion according to claim 11 ,
wherein Step 1 is a step which comprises stirring the silica-based fine particle dispersion containing the silica-based fine particles having projections with a width of 5 to 25 nm on their surfaces and dispersed in a solvent; and continuously or discontinuously adding the cerium metal salt while keeping the temperature at 3 to 20° C., the pH at 7.0 to 9.0 and the oxidation-reduction potential at 50 to 500 mV, respectively, thereby obtaining the precursor particle dispersion containing the precursor particles and in which a ceria-based composite fine particle dispersion comprising ceria-based composite fine particles having an average particle size

Assignees

• Jgc Catalysts & Chemicals Ltd

Inventors

• Komatsu Michio
• Tawarazako Yuji
• Usuda Shinya
• Nakayama Kazuhiro
• Kawakami Shota

Classifications

• H10P52/403

  of conductive or resistive materials · CPC title

• H10P52/402

  of semiconductor materials · CPC title

• H10P52/00

  Grinding, lapping or polishing of wafers, substrates or parts of devices · CPC title

• C09K3/1436 Primary

  Composite particles, e.g. coated particles · CPC title

• C01F17/32 Primary

  oxide or hydroxide being the only anion, e.g. NaCeO2 or MgxCayEuO · CPC title