Ceria-based composite fine particle dispersion, production method therefor, and polishing abrasive grain dispersion including ceria-based composite fine particle dispersion

Patent metadata

Field	Value
Publication number	US-11267715-B2
Application number	US-201816616010-A
Country	US
Kind code	B2
Filing date	May 23, 2018
Priority date	Jun 1, 2017
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

Aiming at providing a ceria-based composite particle dispersion capable of polishing silica film, Si wafer or even hard-to-process material at high polishing rate, and can give high surface accuracy, disclosed is a ceria-based composite particle dispersion that contains a ceria-based composite particle that has an average particle size of 50 to 350 nm, to solve the aforementioned problem, featured by that the ceria-based composite particle has a mother particle, a cerium-containing silica layer, a child particle, and an easily soluble silica-containing layer; the mother particle contains amorphous silica as a major ingredient; the child particle contains crystalline ceria as a major ingredient; ratio of the mass of the easily soluble silica-containing layer relative to the mass of the ceria-based composite particle falls in a specific range; mass ratio of silica and ceria in the ceria-based composite particle falls in a specific range; the ceria-based composite particle, when analyzed by X-ray diffractometry, shows only a crystal phase of ceria; and the ceria-based composite particle has an average crystallite size of the crystalline ceria, when analyzed by X-ray diffractometry, of 10 to 25 nm.

First claim

The invention claimed is:

1. A ceria-based composite particle dispersion, containing a ceria-based composite particle that has an average particle size of 50 to 350 nm and is featured by [1] to [7] below:
[1] the ceria-based composite particle has a mother particle, a cerium-containing silica layer on the surface of the mother particle, and a child particle dispersed inside the cerium-containing silica layer;
[2] the mother particle contains amorphous silica as a major ingredient, and the child particle contains crystalline ceria as a major ingredient;
[3] the ceria-based composite particle has an average crystallite size of the crystalline ceria, when analyzed by X-ray diffractometry, of 10 to 25 nm;
[4] the ceria-based composite particle further has an easily soluble silica-containing layer as the outermost layer;
[5] ratio D of mass D 1 of the easily soluble silica-containing layer to mass D 2 of the ceria-based composite particle (D=D 1 /D 2 ×100) is 0.08 to 30%;
[6] the ceria-based composite particle has a mass ratio of silica and ceria of 100:11 to 316; and
[7] the ceria-based composite particle, when analyzed by X-ray diffractometry, shows only a crystal phase of ceria.

2. The ceria-based composite particle dispersion according to claim 1 ,
wherein the child particle demonstrates a particle size distribution with a coefficient of variation (CV value) of 10 to 60%.

3. The ceria-based composite particle dispersion according to claim 1 , further featured by [8] below:
[8] the crystalline ceria contained as a major ingredient of the child particle has silicon atom solid-solubilized therein.

4. The ceria-based composite particle dispersion according to claim 1 ,
demonstrating a negative streaming potential before being subjected to cation colloidal titration, within the pH range from 3 to 8.

5. The ceria-based composite particle dispersion according to claim 1 ,
demonstrating, when subjected to the cation colloidal titration, a streaming potential curve indicating a ratio (ΔPCD/V), given by formula (1) below, of −110.0 to −15.0, where ΔPCD denotes amount of change of streaming potential, and V denotes amount of addition of a cation colloidal titrant (V) at a knick:
ΔPCD/V=(I-C)/V. . . Formula (1)
C: streaming potential (mV) at the knick;
I: streaming potential (mV) at the start point of the streaming potential curve; and
V: amount of addition of the cation colloidal titrant (ml) at the knick.

6. A ceria-based composite particle dispersion, containing a ceria-based composite particle that has an average particle size of 50 to 350 nm and is featured by [1] to [3] and [9] to [11] below:
[1] the ceria-based composite particle has a mother particle, a cerium-containing silica layer on the surface of the mother particle, and a child particle dispersed inside the cerium-containing silica layer;
[2] the mother particle contains amorphous silica as a major ingredient, and the child particle contains crystalline ceria as a major ingredient
[3] the ceria-based composite particle has an average crystallite size of the crystalline ceria, when analyzed by X-ray diffractometry, of 10 to 25 nm;
[9] the crystalline ceria in the child particle has silicon atom solid-solubilized therein, and additionally has one or more different atoms solid-solubilized therein;
[10] each of contents of cerium, silicon and the different atom(s) in the ceria-based composite particle satisfies a relation given by (Ce+M)/Si=0.038 to 1.11, where M means a total mole number of one or more different atoms, and Ce and Si mean mole numbers of cerium atom and silicon atom, respectively; and
[11] the ceria-based composite particle, when analyzed by X-ray diffractometry, shows (i) only a crystal phase of ceria, or (ii) only a crystal phase of ceria and crystal phase(s) of oxide(s) of the different atom(s).

7. The ceria-based composite particle dispersion according to claim 1 , wherein cerium atom and silicon atom contained in the child particle satisfy a relation given by R 1 <R 2 , where R 1 represents interatomic distance of adjoining cerium and silicon atoms, and R 2 represents interatomic distance of adjoining cerium atoms.

8. The ceria-based composite particle dispersion according to claim 1 ,
wherein the child particle has a geometric mean particle size of 10 to 30 nm.

9. A polishing abrasive particle dispersion containing the ceria-based composite particle dispersion described in claim 1 .

10. The polishing abrasive particle dispersion according to claim 9 , intended to be used for planarizing a semiconductor substrate having a silica film formed thereon.

11. The ceria-based composite particle dispersion according to claim 6 , wherein the different atom is a metal atom.

12. The ceria-based composite particle dispersion according to claim 6 , wherein cerium atom and silicon atom contained in the child particle satisfy a relation given by R 1 <R 2 , where R 1 represents interatomic distance of adjoining cerium and silicon atoms, and R 2 represents interatomic distance of adjoining cerium atoms.

13. The ceria-based composite particle dispersion according to claim 6 , wherein the child particle has a geometric mean particle size of 10 to 30 nm.

14. A polishing abrasive particle dispersion containing the ceria-based composite particle dispersion described in claim 6 .

15. The polishing abrasive particle dispersion according to claim 14 , intended to be used for planarizing a semiconductor substrate having a silica film formed thereon.

Assignees

• Jgc Catalysts & Chemicals Ltd

Inventors

• Komatsu Michio
• Nishida Hiroyasu
• Tawarazako Yuji
• Usuda Shinya
• Nakayama Kazuhiro

Classifications

• H10P52/00

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

• H10P95/062

  involving a dielectric removal step · CPC title

• C01B33/12 Primary

  Silica; Hydrates thereof, e.g. lepidoic silicic acid · CPC title

• C09G1/02 Primary

  containing abrasives or grinding agents {(abrasives as such C09K3/14; polishing of semi-conductors H10P52/40)} · CPC title

• C09K3/1436

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