阅读说明：本技术 一种水玻璃制备超大粒径高浓度硅溶胶的方法 (Method for preparing high-concentration silica sol with ultra-large particle size by using water glass ) 是由 李彦东 林厦涛 叶海峰 皮艳 陈昌貌 于 2020-07-10 设计创作，主要内容包括：本发明提供一种由水玻璃制备超大粒径高浓度硅溶胶的方法,在常规的胶粒制备方法基础上,通过添加非离子型氟碳表面活性剂提高了胶粒表面的结晶活性,再经多次胶粒增长提高了大粒径胶粒的硅酸聚合速度,增大胶粒粒径,通过常压或减压恒液位蒸发或超滤浓缩工艺进行浓缩,制得超大粒径高浓度的硅溶胶,所述硅溶胶具有良好的抛光质量,可以用于超大规模集成电路全局平坦化化学机械抛光(CMP)技术中。(The invention provides a method for preparing high-concentration silica sol with super-large particle size from water glass, which is characterized in that on the basis of a conventional colloidal particle preparation method, the crystallization activity of the surface of colloidal particles is improved by adding a non-ionic fluorocarbon surfactant, the silicic acid polymerization speed of the colloidal particles with the large particle size is increased through multiple colloidal particle growth, the particle size of the colloidal particles is increased, and the silica sol with the super-large particle size and the high concentration is prepared by concentrating through an atmospheric pressure or reduced pressure constant liquid level evaporation or ultrafiltration concentration process.)

1. A method for preparing high-concentration silica sol with ultra-large particle size by using water glass is characterized by comprising the following steps:

s1 preparation of seed crystal mother liquor

Adding active silicic acid solution 2-4 times the volume of the alkaline medium solution into the alkaline medium solution with pH value of 8.5-11 and heated to boiling state, controlling the pH value of the solution within 8.5-11 during the reaction process, keeping the temperature for 10-30min after the addition is finished, cooling after the reaction, standing and aging for 1-24h to obtain SiO₂Seed crystal mother liquor;

s2, colloidal particle growth

Heating the seed crystal mother liquor to a boiling state under normal pressure, controlling the temperature to be continuously in a range of 90-110 ℃, continuously adding 1-2 times of active silicic acid solution in volume of the seed crystal mother liquor under a stirring state, controlling the pH value of the solution to be in a range of 9.50-11.5 in the reaction process, and preserving heat for 10-30min after the addition is finished to obtain solution A;

s3, secondary growth of colloidal particles

Dropwise adding a non-ionic fluorocarbon surfactant intechem-06 with the volume fraction of 0.01-0.1% of the system into the solution A, continuously adding an active silicic acid solution with the volume 1-2 times that of the seed crystal mother liquor under the stirring state, controlling the pH value of the solution within the range of 9.50-11.5 in the reaction process, and preserving heat for 10-30min after the addition is finished to obtain a solution B;

s4, colloidal particle enlargement

And (3) carrying out the step S3 again for 1-2 times by using the solution B, preserving the heat for 10-30min after the reaction is finished, controlling the concentration of the solution to be 20-50% by using a normal-pressure or reduced-pressure constant-liquid-level evaporation or ultrafiltration concentration process, cooling, standing and aging for 1-24h, and purifying by using an impurity removal process to obtain the silica sol with the ultra-large particle size and the high concentration, wherein the particle size is 140-160 nm.

2. The method for preparing the silica sol with the ultra-large particle size and the high concentration by using the water glass as claimed in claim 1, wherein the alkaline medium solution is a sodium hydroxide or potassium hydroxide solution with the concentration of 2-10%.

3. The method for preparing the silica sol with the ultra-large particle size and the high concentration by using the water glass as claimed in claim 1, wherein the preparation method of the active silicic acid solution comprises the following steps:

and (3) performing ion exchange on the diluted water glass through cation exchange resin to remove sodium ions and cation impurities to obtain the active silicic acid solution, wherein the concentration of the active silicic acid solution is 4-30%.

4. The method for preparing the silica sol with the ultra-large particle size and the high concentration by using the water glass as claimed in claim 3, wherein the concentration of the diluted water glass is 6-10%.

5. The method for preparing the silica sol with the ultra-large particle size and the high concentration by using the water glass as claimed in claim 3, wherein the cation exchange resin is a strongly acidic polystyrene cation exchange resin.

6. The method for preparing the silica sol with the ultra-large particle size and the high concentration by using the water glass as claimed in claim 1, wherein the SiO is prepared by using the silica sol₂The concentration of the seed crystal mother liquor is 4-30%.

7. The method for preparing silica sol with ultra-large particle size and high concentration by using water glass as claimed in claim 1, wherein after the step of S1 and before the step of S2, 0.2-1% of polyethylene glycol 6000 is added into the seed crystal mother liquor, and then the high-pressure homogenization or ultrasonic disruption treatment is carried out.

8. The method for preparing ultra-large particle size high concentration silica sol according to claim 1, wherein 0.4-1.2% methyltrimethoxysilane is added to the system during the standing aging in step S4.

9. A very large particle size high concentration silica sol prepared according to the process of any one of claims 1 to 8.

10. Use of the ultra large particle size high concentration silica sol according to claim 9 for the manufacture of polishing solutions.

Technical Field

The invention relates to the technical field of silica sol preparation, in particular to a method for preparing high-concentration silica sol with super-large particle size by using water glass.

Background

With the high development of integrated circuit technology, the surface quality of the substrate material used is more and more demanding. In order to make the surface of the precision electronic device meet the requirement of nano-level flatness, the chemical mechanical polishing technology (CMP polishing for short) is adopted to process the surface of the precision electronic device in the current industrial production. The CMP polishing technology mainly achieves planarization of the material surface by means of the combined action of mechanical grinding and chemical corrosion of inorganic nanoparticles. In the CMP polishing process, the used polishing solution mainly comprises nanometer silica sol, an auxiliary agent, deionized water and the like. The silica sol is used as an important component of the polishing solution, and the sphericity, size, particle size distribution and the like of the nano particles of the silica sol can influence the surface removal rate and surface flatness of the polishing material, so that the polishing quality of the surface of the material is influenced.

Silica sol is a colloidal solution in which colloidal particles of silica are dispersed in water, and is an important inorganic material. Because the surface of the silicon dioxide particles in the silica sol has a large amount of hydroxyl groups and has larger reaction activity, the silicon dioxide particles in the silica sol are widely applied in the fields of chemical industry, precision casting, spinning, papermaking, coating, food, electronics, mineral separation and the like.

The current main preparation method of the silica sol is an ion exchange method, wherein water glass is used as a raw material, the water glass is treated by cation exchange resin to obtain mother liquor containing crystal nuclei, then dilute silicic acid solution is dropwise added into the mother liquor containing the crystal nuclei, the growth speed of the crystal nuclei is controlled, and then a silica sol product is prepared through a concentration process; however, most of the silica sol particles prepared by the method have the defects of unclear interparticle boundary and uneven particle size distribution, and colloidal particles with smaller particle size have quite limited mechanical action during polishing and low polishing speed.

Disclosure of Invention

Aiming at the problems, the invention provides a method for preparing high-concentration silica sol with ultra-large particle size by using water glass.

The purpose of the invention is realized by adopting the following technical scheme:

a method for preparing high-concentration silica sol with ultra-large particle size by using water glass comprises the following steps:

s1 preparation of seed crystal mother liquor

Adding active silicic acid solution 2-4 times of the alkaline medium solution volume into the alkaline medium solution with pH of 8.5-11 and heated to boiling state, controlling the pH of the solution in the reaction process within 8.5-11, and finishing the additionKeeping the temperature for 10-30min after formation, cooling after reaction, standing and aging for 1-24h to obtain SiO₂Seed crystal mother liquor;

s2, colloidal particle growth

Heating the seed crystal mother liquor to a boiling state under normal pressure, controlling the temperature to be continuously in a range of 90-110 ℃, continuously adding 1-2 times of active silicic acid solution in volume of the seed crystal mother liquor under a stirring state, controlling the pH value of the solution to be in a range of 9.50-11.5 in the reaction process, and preserving heat for 10-30min after the addition is finished to obtain solution A;

s3, secondary growth of colloidal particles

Dropwise adding a non-ionic fluorocarbon surfactant intechem-06 with the volume fraction of 0.01-0.1% of the system into the solution A, continuously adding an active silicic acid solution with the volume 1-2 times that of the seed crystal mother liquor under the stirring state, controlling the pH value of the solution within the range of 9.50-11.5 in the reaction process, and preserving heat for 10-30min after the addition is finished to obtain a solution B;

s4, colloidal particle enlargement

And (3) carrying out the step S3 again for 1-2 times by using the solution B, preserving the heat for 10-30min after the reaction is finished, controlling the concentration of the solution to be 20-50% by using a normal-pressure or reduced-pressure constant-liquid-level evaporation or ultrafiltration concentration process, cooling, standing and aging for 1-24h, and purifying by using an impurity removal process to obtain the silica sol with the ultra-large particle size and the high concentration, wherein the particle size is 140-160 nm.

Preferably, the alkaline medium is sodium hydroxide or potassium hydroxide solution with the concentration of 2-10%;

preferably, the preparation method of the active silicic acid solution comprises the following steps:

and (3) performing ion exchange on the diluted water glass through cation exchange resin to remove sodium ions and cation impurities to obtain the active silicic acid solution, wherein the concentration of the active silicic acid solution is 4-30%.

Further preferably, the concentration of the diluted water glass is 6-10%.

Further preferably, the cation exchange resin is a strongly acidic polystyrene cation exchange resin.

Preferably, the SiO₂The concentration of the seed crystal mother liquor is 4-30%.

Preferably, after the step of S1 and before the step of S2, 0.2 to 1 percent of polyethylene glycol 6000 is added into the seed crystal mother liquor, and then high-pressure homogenization or ultrasonic crushing treatment is carried out.

Preferably, in the S4 step, 0.4-1.2% of methyltrimethoxysilane is added to the system during standing and aging.

The second purpose of the present invention is to provide an application of the silica sol prepared by the above preparation method to the preparation of polishing solutions.

The invention has the beneficial effects that:

on the basis of a conventional colloidal particle preparation method, the crystallization activity of the surface of colloidal particles is improved by adding a non-ionic fluorocarbon surfactant, the silicic acid polymerization speed of large-particle-size colloidal particles is improved through multiple growth, the particle size of the colloidal particles is increased, and then the colloidal particles are concentrated through a normal-pressure or reduced-pressure constant-liquid-level evaporation or ultrafiltration concentration process to prepare the silica sol with the ultra-large particle size and high concentration, so that the silica sol can be used in the global planarization Chemical Mechanical Polishing (CMP) technology of an ultra-large scale integrated circuit.

Detailed Description

The invention is further described with reference to the following examples.

The embodiment of the invention relates to a method for preparing silica sol with ultra-large particle size and high concentration by using water glass, which comprises the following steps:

s1 preparation of seed crystal mother liquor

Adding active silicic acid solution 2-4 times the volume of the alkaline medium solution into the alkaline medium solution with pH value of 8.5-11 and heated to boiling state, controlling the pH value of the solution within 8.5-11 during the reaction process, keeping the temperature for 10-30min after the addition is finished, cooling after the reaction, standing and aging for 1-24h to obtain SiO₂Seed crystal mother liquor;

s2, colloidal particle growth

Heating the seed crystal mother liquor to a boiling state under normal pressure, controlling the temperature to be continuously in a range of 90-110 ℃, continuously adding 1-2 times of active silicic acid solution in volume of the seed crystal mother liquor under a stirring state, controlling the pH value of the solution to be in a range of 9.50-11.5 in the reaction process, and preserving heat for 10-30min after the addition is finished to obtain solution A;

s3, secondary growth of colloidal particles

Dropwise adding a non-ionic fluorocarbon surfactant intechem-06 with the volume fraction of 0.01-0.1% of the system into the solution A, continuously adding an active silicic acid solution with the volume 1-2 times that of the seed crystal mother liquor under the stirring state, controlling the pH value of the solution within the range of 9.50-11.5 in the reaction process, and preserving heat for 10-30min after the addition is finished to obtain a solution B;

s4, colloidal particle enlargement

And (3) carrying out the step S3 again for 1-2 times by using the solution B, preserving the heat for 10-30min after the reaction is finished, controlling the concentration of the solution to be 20-50% by using a normal-pressure or reduced-pressure constant-liquid-level evaporation or ultrafiltration concentration process, cooling, standing and aging for 1-24h, and purifying by using an impurity removal process to obtain the silica sol with the ultra-large particle size and the high concentration, wherein the particle size is 140-160 nm.

The colloidal particles with small particle size have quite limited mechanical action during polishing, the polishing speed is low, and the silica sol with large particle size can obviously improve the quality and the assembly precision of the polished surfaces of various silicon wafers; in the conventional preparation process of the silica sol, the polymerization speed of silicic acid is gradually reduced along with the increase of the particle size of silica colloidal particles, so that the growth of silica colloidal particles with large particle size is influenced.

Preferably, the alkaline medium is sodium hydroxide or potassium hydroxide solution with the concentration of 2-10%;

preferably, the preparation method of the active silicic acid solution comprises the following steps:

and (3) performing ion exchange on the diluted water glass through cation exchange resin to remove sodium ions and cation impurities to obtain the active silicic acid solution, wherein the concentration of the active silicic acid solution is 4-30%.

The water glass can be sodium silicate or potassium silicate, potassium silicate and potassium hydroxide are used as raw materials, potassium type silica sol can be prepared, and potassium ions have larger radius than sodium ions and are not easy to permeate into crystal lattices of silicon single crystals during polishing, so that the water glass has more advantages in polishing application.

Further preferably, the concentration of the diluted water glass is 6-10%.

Further preferably, the cation exchange resin is a strongly acidic polystyrene cation exchange resin.

Preferably, the SiO₂The concentration of the seed crystal mother liquor is 4-30%.

Preferably, after the step of S1 and before the step of S2, 0.2 to 1 percent of polyethylene glycol 6000 is added into the seed crystal mother liquor, and then high-pressure homogenization or ultrasonic crushing treatment is carried out.

The conventional colloidal particle preparation method, namely the particle size distribution of the silicon dioxide colloidal particles prepared by the ion exchange method is wide, the preparation of the large-particle-size sol can be realized by adding the non-ionic fluorocarbon surfactant, but the particle size distribution is not uniform; according to the method, the prepared seed crystal mother liquor is subjected to high-pressure homogenization or ultrasonic crushing treatment, so that on one hand, the seed crystal with larger particle size can be damaged, and thus the seed crystal mother liquor with small particle size and uniform distribution is obtained, and on the other hand, the seed crystal mother liquor is cooperated with polyethylene glycol to obtain good dispersibility; the treatment method is more preferably high-pressure homogenization treatment, and can also induce the further growth of crystal nuclei under the high-pressure condition to obtain crystal nuclei with larger particle size, thereby being beneficial to the growth and preparation of large-particle-size colloidal particles.

Preferably, in the S4 step, 0.4-1.2% of methyltrimethoxysilane is added to the system during standing and aging.

Can take place condensation polymerization spontaneously between the hydroxyl on silica sol surface and form the silica ether bond to with adjacent micelle crosslinking together, finally form the gel, destroyed the stability of silica sol, this application makes the hydroxyl passivation on silica sol surface as the anticoagulant through adding alkoxysilane, micelle granule surface partial hydroxyl is substituted by organic group, has increased the steric hindrance between the granule, reduces reactivity, makes metastable state silica sol have higher stability.