阅读说明：本技术 球形二氧化硅纳米颗粒浆料的制备方法 (Preparation method of spherical silicon dioxide nanoparticle slurry ) 是由 张纪尧 甄崇礼 于 2019-11-28 设计创作，主要内容包括：本发明涉及制备二氧化硅纳米颗粒技术领域,具体涉及一种球形二氧化硅纳米颗粒浆料的制备方法。球形二氧化硅纳米颗粒浆料的制备过程在沉淀老化反应器中进行；沉淀老化反应器包括釜体,釜体上部设置离心混合器,离心混合器中心设置液体分布器；釜体下部为老化区；反应物A和反应物B经管路进入液体分布器中,均匀混合后反应,反应后的料浆进入老化区老化,在保持老化区一定持液量的情况下,连续出料,形成连续生产；流出的料浆经减压蒸发浓缩,形成粒径在10-200nm之间的球形二氧化硅纳米颗粒浆料。本发明得到的二氧化硅纳米颗粒浆料的固含量高,其中二氧化硅纳米颗粒的粒径大小可控且粒径均匀。(The invention relates to the technical field of preparation of silicon dioxide nanoparticles, in particular to a preparation method of spherical silicon dioxide nanoparticle slurry. The preparation process of the spherical silicon dioxide nano-particle slurry is carried out in a precipitation aging reactor; the precipitation aging reactor comprises a kettle body, wherein a centrifugal mixer is arranged at the upper part of the kettle body, and a liquid distributor is arranged at the center of the centrifugal mixer; the lower part of the kettle body is an aging area; the reactant A and the reactant B enter a liquid distributor through a pipeline, are uniformly mixed and then react, slurry after reaction enters an aging zone for aging, and is continuously discharged under the condition of keeping a certain liquid holding capacity of the aging zone, so that continuous production is formed; and evaporating and concentrating the outflow slurry under reduced pressure to form spherical silicon dioxide nano-particle slurry with the particle size of 10-200 nm. The solid content of the silicon dioxide nano particle slurry obtained by the invention is high, wherein the particle size of the silicon dioxide nano particles is controllable and uniform.)

1. A preparation method of spherical silicon dioxide nanoparticle slurry is characterized by comprising the following steps: the preparation process of the spherical silicon dioxide nano-particle slurry is carried out in a precipitation aging reactor; the precipitation aging reactor comprises a kettle body (3), wherein a centrifugal mixer (6) arranged on a stirring paddle (10) is arranged at the upper part of the kettle body (3), and a liquid distributor (5) is arranged at the center of the centrifugal mixer (6); the lower part of the kettle body (3) is an aging area;

the reactant A and the reactant B enter a liquid distributor (5) positioned in the center of a centrifugal mixer (6), move from the inside to the outside of the centrifugal mixer (6) along the radial direction under the centrifugal force, the reactant A and the reactant B are uniformly mixed and react under the action of the centrifugal mixer (6), the reacted slurry enters an aging zone for aging, and the continuous discharge is realized under the condition of keeping a certain liquid retention amount in the aging zone to form continuous production; and (3) the slurry flowing out of the precipitation aging reactor is evaporated and concentrated under reduced pressure to form spherical silicon dioxide nanoparticle slurry with the particle size of 10-200 nm.

2. The method for preparing a spherical silica nanoparticle slurry according to claim 1, characterized in that: the reactant A is alkoxy silane or a mixture of alkoxy silane and a first organic solvent; the molar ratio of the alkoxysilane to the first organic solvent is 1: 0-5.

3. The method for preparing a spherical silica nanoparticle slurry according to claim 2, characterized in that: the alkoxy silane comprises one or more of methoxy silane, ethoxy silane, propoxy silane or butoxy silane.

4. The method for preparing a spherical silica nanoparticle slurry according to claim 3, characterized in that: the alkoxy silane is tetramethoxy silane or tetraethoxy silane.

5. The method for preparing a spherical silica nanoparticle slurry according to claim 2, characterized in that: the first organic solvent includes one or more of methanol, ethanol, ethylene glycol, propanol, propylene glycol, glycerol, or butanol.

6. The method for preparing a spherical silica nanoparticle slurry according to claim 1, characterized in that: reactant B comprises a base catalyst, water and a second organic solvent; the molar ratio of water to the base catalyst is 1-50: 1; the molar ratio of the second organic solvent to the base catalyst is 1-50: 1.

7. The method for preparing a spherical silica nanoparticle slurry according to claim 6, wherein: the alkali catalyst comprises one or more of sodium hydroxide, potassium hydroxide, organic amine, quaternary ammonium base or ammonia water.

8. The method for preparing a spherical silica nanoparticle slurry according to claim 6, wherein: the second organic solvent comprises one or more of methanol, ethanol, ethylene glycol, propanol, propylene glycol, glycerol or butanol.

9. The method for preparing a spherical silica nanoparticle slurry according to claim 2 or 6, characterized in that: the molar ratio of the alkoxysilane to the base catalyst is 1: 0.01-2.

10. The method for preparing a spherical silica nanoparticle slurry according to claim 1, characterized in that: the temperature of the reactant A, the reactant B, the slurry in the aging area and the slurry flowing out of the precipitation aging reactor are controlled to be 0-60 ℃; the pH value of slurry flowing out of the precipitation aging reactor is 9-12, and the solid content is controlled to be 5-15 wt.%; the solid content of the spherical silica nanoparticle slurry is 30-40 wt.%.

Technical Field

The invention relates to the technical field of preparation of silicon dioxide nanoparticles, in particular to a preparation method of spherical silicon dioxide nanoparticle slurry.

Background

To date, ultra-precise chemical mechanical polishing CMP techniques have provided integration in integrated circuit IC and ULSI fabrication of very large or very large scale integrated circuitsThe only technique for surface finishing of planarization. And silicon dioxide SiO₂The sol polishing solution is an important polishing medium in the CMP technology, and is mainly used for rough polishing and fine polishing of silicon substrates and polishing of interlayer media. The silica sol belongs to a colloidal solution, is a dispersion of nano-scale silica particles in water or a solvent, and is odorless and nontoxic.

At present, the effective component of the polishing solution for fine polishing of silicon dioxide is mainly spherical silicon dioxide nano-particle sol, and the following preparation methods are available:

(1) the water glass is used as a raw material, a nano-scale nucleus is formed through ion exchange, and then the nucleus grows into nano-particles in an aqueous solution, so that the colloidal form is basically maintained, and long-term stability can be realized through adjustment. The high-concentration colloidal silicon dioxide can be prepared by adopting different concentration modes, and is convenient to transport and store. The colloidal silicon dioxide is not dried and dehydrated in the preparation process, so that the colloidal silicon dioxide is moderate in hardness, does not scratch a wafer due to the hardness, is low in viscosity and weak in adhesion, is easy to clean after polishing, and is widely used for roughly polishing and finely polishing silicon wafers. However, the method for preparing the large-particle-size colloidal silica has the defects of complex process, difficult growth, non-uniform particles and wide particle size distribution, and cannot meet the requirements of a fine line process.

(2) The sol-gel method takes alkoxy silane as raw material, takes hydrolysis reaction under the action of alkali catalyst, and can prepare the silicon dioxide abrasive with consistent grain diameter and higher purity by controlling hydrolysis conditions. But is mainly used for high-end requirements, such as chip level, due to higher raw material cost. However, the method for producing a silica sol in which alkoxysilane is hydrolyzed under base catalysis to give a synthetic route has the following disadvantages:

a. the reaction is carried out by using a conventional batch reactor, the concentration of a reaction product cannot be higher than about 5 percent, otherwise, a reaction system can generate a viscous phenomenon, so that the production efficiency is lower;

b. when the synthetic route is used for preparing the silica sol, the mixing state of the materials has great influence on the quality of the product. In the reaction process, if the two components cannot be uniformly mixed in a short time, the local reaction concentration is too high, and the uniformity of final product particles is influenced, so that the quality of the product is influenced.

Disclosure of Invention

The invention aims to provide a preparation method of spherical silicon dioxide nanoparticle slurry, which has high solid content, wherein the particle size of silicon dioxide nanoparticles is controllable and uniform.

The preparation method of the spherical silicon dioxide nanoparticle slurry comprises the following steps: the preparation process of the spherical silicon dioxide nano-particle slurry is carried out in a precipitation aging reactor; the precipitation aging reactor comprises a kettle body, wherein a centrifugal mixer arranged on a stirring paddle is arranged at the upper part of the kettle body, and a liquid distributor is arranged at the center of the centrifugal mixer; the lower part of the kettle body is an aging area;

the reactant A and the reactant B enter a liquid distributor positioned in the center of a centrifugal mixer, move from the inside of the centrifugal mixer to the outside along the radial direction under the centrifugal force, the reactant A and the reactant B are uniformly mixed and react under the action of the centrifugal mixer, slurry after reaction enters an aging zone for aging, and is continuously discharged under the condition of keeping a certain liquid retention amount in the aging zone to form continuous production; and (3) the slurry flowing out of the precipitation aging reactor is evaporated and concentrated under reduced pressure to form spherical silicon dioxide nanoparticle slurry with the particle size of 10-200 nm.

Wherein:

the reactant A is alkoxy silane or a mixture of alkoxy silane and a first organic solvent; the molar ratio of alkoxysilane to first organic solvent is from 1:0 to 5, preferably from 1:0 to 2.

The alkoxy silane comprises one or more of methoxy silane, ethoxy silane, propoxy silane or butoxy silane, and preferably tetramethoxy silane or tetraethoxy silane.

The first organic solvent comprises one or more of methanol, ethanol, glycol, propanol, propylene glycol, glycerol or butanol.

The reactant B comprises a base catalyst, water and a second organic solvent; the molar ratio of water to the base catalyst is 1-50: 1; the molar ratio of the second organic solvent to the base catalyst is 1-50: 1.

The alkali catalyst comprises one or more of sodium hydroxide, potassium hydroxide, organic amine, quaternary ammonium base or ammonia water.

The second organic solvent comprises one or more of methanol, ethanol, ethylene glycol, propanol, propylene glycol, glycerol or butanol.

The molar ratio of the alkoxy silane to the base catalyst is 1:0.01-2, preferably 1:0.05-1, more preferably 1: 0.1-0.5.

The temperature of the reactant A, the reactant B, the slurry in the aging area and the slurry flowing out of the precipitation aging reactor are controlled to be 0-60 ℃, preferably 10-50 ℃, and more preferably 20-40 ℃.

The pH value of the slurry flowing out of the precipitation aging reactor is 9-12, and the solid content is controlled to be 5-15 wt.%, preferably 13-14 wt.%; the solid content of the spherical silica nanoparticle slurry is 30-40 wt.%.

The preparation process of the spherical silicon dioxide nanoparticle slurry is carried out in a precipitation aging reactor, the precipitation aging reactor comprises a kettle body, the upper part of the kettle body is provided with a centrifugal mixer, the lower part of the kettle body is an aging area, a stirring paddle is arranged in the aging area, the centrifugal mixer is connected with a rotating shaft of the stirring paddle, the top of the rotating shaft is provided with a variable frequency motor, and the variable frequency motor drives the centrifugal mixer and the stirring paddle to rotate together; the center of the centrifugal mixer is provided with a liquid distributor; the liquid distributor is respectively connected with the storage tank A and the storage tank B through a flowmeter; centrifugal pumps are respectively arranged on pipelines connecting the liquid distributor with the storage tank A and the storage tank B. The storage tank A and the storage tank B respectively store a reactant A and a reactant B.

The material of the centrifugal mixer 6 can be metal or high molecular polymer, and the inside of the centrifugal mixer 6 is filled with wire mesh filler.

The reactant A and the reactant B are conveyed by a centrifugal pump, enter a liquid distributor positioned in the center of a centrifugal mixer through a flowmeter along a pipeline, move from the inside to the outside of the centrifugal mixer along the radial direction under the centrifugal force, are uniformly mixed and react under the action of the centrifugal mixer, and slurry after reaction enters an aging zone for aging, and is continuously discharged under the condition of keeping a certain liquid retention amount in the aging zone to form continuous production; and (3) the slurry flowing out of the precipitation aging reactor is subjected to reduced pressure evaporation concentration to remove redundant organic solvent and volatile reactants in the slurry, so as to form spherical silicon dioxide nanoparticle slurry with the particle size of 10-200 nm.

The invention has the following beneficial effects:

(1) according to the invention, the centrifugal mixer is arranged above the interior of the precipitation aging reactor, and the liquid distributor is arranged in the center of the centrifugal mixer, so that the reactant A and the reactant B can be mixed very uniformly in a short time, the reaction is more thorough, and the phenomenon of overhigh local reaction concentration is avoided; and (3) the reacted slurry enters an aging zone for further aging, and the particle size of the silicon dioxide in the obtained spherical silicon dioxide nano-particle slurry is between 10 and 200nm and is uniform through reduced pressure evaporation and concentration.

(2) The invention adopts the centrifugal mixer to mix and react the reactants, so that the ratio of the reactants is always kept consistent in the production process, the two reactants are uniformly mixed, the constancy of the reaction process state and the uniformity of the reaction product are ensured, and the uniformity of the particle size of the silicon dioxide particles is ensured. In addition, the silica particle slurry enters the aging zone, which can further increase the stability of the silica particles. The precipitation aging reactor can avoid the back mixing phenomenon of reactants, thereby avoiding the formation of uneven silicon dioxide particles.

(3) The slurry prepared by the existing batch reaction kettle is easy to crosslink particles formed in the continuous reaction process of one reactant and the other reactant because one reactant is always in a highly excessive state, so that the concentration of a reaction product can only reach about 5 wt%; if the reactant concentration is too high, the reaction slurry becomes more viscous and loses fluidity. The centrifugal mixer is adopted for mixing the reactants, so that the high excessive amount of the reactants is avoided, the crosslinking of the silica particles is avoided, the solid content of slurry in the precipitation aging reactor can reach about 14 wt.%, the solid content of the obtained spherical silica nanoparticle slurry is 30-40 wt.%, and the production efficiency is greatly improved.

(4) The centrifugal mixer and the aging zone are coupled together, so that the reacted materials can enter the aging zone in time, and the materials are discharged continuously under the condition of keeping a certain liquid holding capacity of the aging zone, thereby realizing continuous production and improving the yield.

Drawings

FIG. 1 is a schematic diagram of the structure of the apparatus of the present invention;

wherein: 1. a storage tank A; 2. a flowmeter A; 3. a kettle body; 4. a variable frequency motor; 5. a liquid distributor; 6. a centrifugal mixer; 7. a flow meter B; 8. a storage tank B; 9. a centrifugal pump B; 10. a stirring paddle; 11. a centrifugal pump A;

FIG. 2 is a scanning electron micrograph of spherical silica nanoparticles obtained in example 1;

FIG. 3 is a scanning electron micrograph of spherical silica nanoparticles obtained in example 2;

FIG. 4 is a scanning electron micrograph of spherical silica nanoparticles obtained in example 3;

FIG. 5 is a scanning electron micrograph of spherical silica nanoparticles obtained in example 4;

FIG. 6 is a scanning electron micrograph of spherical silica nanoparticles obtained in example 5;

fig. 7 is a scanning electron micrograph of the spherical silica nanoparticles obtained in example 6.

Detailed Description

The present invention is further described below with reference to examples.