Synthetic method of alpha-aluminum oxide nano-particles, alpha-aluminum oxide nano-particles and application of alpha-aluminum oxide nano-particles

Abstract

The invention discloses a method for preparing alpha-alumina nanoparticles, which comprises the following steps of: firstly synthesizing a nano precursor, further roasting the synthesized precursor to obtain the alpha-alumina nanoparticles with adjustable particle size between 80 and 200nm, and dispersing to obtain the alpha-alumina nanoparticles which can be used as a chemical mechanical polishing liquid abrasive material for chemical mechanical polishing of an integrated circuit.

Description

Technical Field

[0001] The present invention relates to the field of chemical mechanical polishing, and particularly to a method for synthesizing α-aluminum oxide nanoparticles, an α-aluminum oxide nanoparticle, and its use. Background Art

[0002] There are more than a dozen different crystal phases of alumina, among which α-aluminum oxide is a thermodynamically stable phase and has high chemical stability. Its Mohs hardness is as high as 9, so it has a wide range of applications. Nano-scale α-aluminum oxide, as an important abrasive particle, is applied in the chemical mechanical polishing process, especially in the polishing process of advanced semiconductor manufacturing processes, and has irreplaceable application characteristics. At the same time, it also shows excellent polishing characteristics in the polishing of the third-generation semiconductor silicon carbide. The purity, particle size, and morphological characteristics of α-aluminum oxide nanoparticles have a direct impact on their polishing performance. Under normal conditions, it is necessary to calcine the precursor at a temperature above 1200 degrees to obtain α-aluminum oxide. High-temperature calcination inevitably causes serious hard agglomeration of α-aluminum oxide particles and severe necking between particles, making it difficult to obtain nano-scale α-aluminum oxide particles with specific morphological characteristics. Summary of the Invention

[0003] In order to overcome the above technical defects, the purpose of the present invention is to provide a method for controllably synthesizing α-aluminum oxide nanoparticles.

[0004] The present invention discloses a method for preparing α-aluminum oxide nanoparticles, which is characterized by including:

[0005] S1) Synthesize a precursor of aluminum oxide by using a molecular aluminum source or Al2O3·nH2O and preparing it by a sol-gel method at a first temperature under acidic or alkaline conditions; S2) Mix the precursor with α-aluminum oxide nanoparticle seeds of different particle sizes at a certain mass ratio;

[0006] S3) Dry and disperse the mixed sample, and then calcine it in a muffle furnace at a second temperature to obtain α-aluminum oxide powder.

[0007] Further, the molecular aluminum source includes, but is not limited to, one or a mixture of more than one of ammonium aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum isopropoxide, aluminum sec-butoxide, etc.

[0008] Further, the sol auxiliary agent under alkaline conditions includes, but is not limited to, one or a mixture of more than one of ammonium carbonate, ammonium bicarbonate, ammonia water, ammonium sulfate, ammonium chloride, potassium hydroxide, etc.

[0009] Further, the sol auxiliary agent under acidic conditions includes, but is not limited to, one or a mixture of several of nitric acid, hydrochloric acid, acetic acid, sulfuric acid, citric acid, etc.

[0010] Further, the reaction temperature of the precursor prepared by the sol method, the first temperature, is from room temperature to 120 °C.

[0011] Further, the precursor prepared by the sol method is mixed with α-aluminum oxide nanoparticle seeds in a certain proportion. The mass ratio of the α-aluminum oxide nanoparticle seeds to the precursor is 0.5 wt% to 50 wt%, and the preferred mass ratio is 2 wt% to 20 wt%.

[0012] Further, the particle size of the α-aluminum oxide nanoparticle seeds is 20 to 180 nm.

[0013] Further, the mixed sample is dried, dispersed and then calcined in a muffle furnace to obtain α-aluminum oxide powder. The drying methods include but are not limited to drying, freeze-drying, etc.; the dispersion methods include but are not limited to mechanical crushing, air flow crushing, ball milling, etc.

[0014] Further, the calcination temperature, the second temperature, is 700 to 1100 °C, and the preferred temperature is 800 to 1000 °C.

[0015] Further, the α-aluminum oxide powder prepared by the above preparation method of α-aluminum oxide nanoparticles is subjected to a dispersion treatment to obtain a nano-α-aluminum oxide dispersion; the dispersion conditions include but are not limited to ball milling, sand milling, high-speed shearing, etc.

[0016] On the other hand, the present invention provides α-aluminum oxide nanoparticles synthesized by any one of the above synthesis methods.

[0017] On the other hand, the present invention provides a use of the above α-aluminum oxide nanoparticles for chemical mechanical polishing.

[0018] After adopting the above technical solutions, compared with the prior art, the following beneficial effects are achieved:

[0019] 1. Nano-precursors synthesize α-aluminum oxide powders with different particle sizes with the assistance of seeds with different particle sizes.

[0020] 2. The synthesized α-aluminum oxide powders have uniform morphology, uniform particle size and high purity. Description of the Drawings

[0021] Figure 1 It is the X-ray diffraction pattern of the product of Example 3;

[0022] Figure 2 It is the particle size distribution diagram of the product of Example 6. Detailed Embodiments

[0023] The advantages of the present invention are further elaborated below with specific embodiments.

[0024] According to the synthesis method shown in Table 1, α-aluminum oxide nanoparticles of Examples 1-9 and the comparative example were synthesized. The examples are intended to illustrate the specific implementation manners of the present invention, but the protection scope of the present invention is not limited to the following examples only. Examples of specific synthesis conditions are as follows:

[0025] Example 3: Aluminum isopropoxide was added to a certain amount of water. After stirring for a period of time, nitric acid was added to promote its hydrolysis to obtain a nano-precursor, and the reaction temperature was controlled at 85 °C. α-aluminum oxide nanoparticle seeds with a particle size of 50 nm were mixed with the nano-precursor, and the mass ratio of the seeds to the precursor was controlled at 10%. The mixed sample was dried, dispersed, and then calcined in a muffle furnace at 900 °C to obtain α-aluminum oxide powder. After the powder was dispersed, an α-aluminum oxide dispersion could be obtained, and the dispersed α-aluminum oxide nanoparticles could be used as abrasive particles in the polishing field.

[0026] Example 6: Aluminum chloride was added to a certain amount of water and fully stirred at room temperature to dissolve it. A certain amount of potassium hydroxide was added to the above aluminum chloride solution to promote the conversion of the molecular aluminum source into a nano-precursor. α-aluminum oxide nanoparticle seeds with a particle size of 110 nm were mixed with the nano-precursor, and the mass ratio of the seeds to the precursor was controlled at 0.5%. The mixed sample was dried, dispersed, and then calcined in a muffle furnace at 1100 °C to obtain α-aluminum oxide powder. After the powder was dispersed, an α-aluminum oxide dispersion could be obtained, and the dispersed α-aluminum oxide nanoparticles could be used as abrasive particles in the polishing field.

[0027] Comparative example: A certain amount of ammonium aluminum sulfate and ammonium bicarbonate were respectively dissolved in water. The ammonium aluminum sulfate solution was added to the ammonium bicarbonate solution, and the reaction was carried out at 50 °C for a period of time to obtain a precursor. The precursor was dried, dispersed, and then calcined in a muffle furnace at 1100 °C to obtain α-aluminum oxide powder. After the powder was dispersed, an α-aluminum oxide dispersion could be obtained.

[0028] Table 1: α-aluminum oxide synthesis experimental conditions

[0029]

[0030]

[0031] The α-aluminum oxide powders synthesized by the method shown in Table 1 have uniform morphology, uniform particle size, and high purity. The α-aluminum oxide nanoparticles after dispersion treatment can be used as abrasive particles in the polishing field.

[0032] It should be noted that the embodiments of the present invention have better implementability and do not impose any form of limitation on the present invention. Any person skilled in the art may use the technical content disclosed above to modify or transform it into equivalent effective embodiments. However, as long as it does not depart from the technical solution of the present invention, any modification, equivalent change or modification made to the above embodiments based on the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for preparing α-aluminum oxide nanoparticles, characterized in that, Comprising: S1) Synthesize a precursor of alumina, select a molecular aluminum source or Al2O3·nH2O, and prepare it by sol-gel method at a first temperature under acidic or alkaline conditions; S2) Mix the precursor with α-alumina nanoparticle seeds of different particle sizes in a certain mass ratio; S3) Calcinate the mixed sample in a muffle furnace at a second temperature after drying and dispersion to obtain α-alumina powder.

2. The preparation method of α-aluminum oxide nanoparticles according to claim 1, characterized in that, The molecular aluminum source described includes one or more of ammonium aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum isopropoxide, and aluminum sec-butoxide.

3. The preparation method of α-aluminum oxide nanoparticles according to claim 1, characterized in that, The sol auxiliary under the alkaline condition includes one or more of ammonium carbonate, ammonium bicarbonate, ammonia water, ammonium sulfate, ammonium chloride, and potassium hydroxide.

4. The preparation method of α-aluminum oxide nanoparticles according to claim 1, characterized in that, The sol auxiliary under the acidic condition includes one or more of nitric acid, hydrochloric acid, acetic acid, sulfuric acid, and citric acid.

5. The preparation method of α-aluminum oxide nanoparticles according to claim 1, characterized in that, The first temperature is room temperature - 120°C.

6. The preparation method of α-aluminum oxide nanoparticles according to claim 1, characterized in that, The mass ratio of the α-alumina nanoparticle seeds to the precursor is 0.5wt% - 50wt%.

7. The preparation method of α-aluminum oxide nanoparticles according to claim 6, characterized in that, The mass ratio of the α-alumina nanoparticle seeds to the precursor is 2wt% - 20wt%.

8. The preparation method of α-aluminum oxide nanoparticles according to claim 1, characterized in that, The particle size of the α-alumina nanoparticle seeds described is 20 - 180nm.

9. The preparation method of α-aluminum oxide nanoparticles according to claim 1, characterized in that, The drying described includes drying by baking and freeze-drying.

10. The preparation method of α-aluminum oxide nanoparticles according to claim 1, characterized in that, The dispersion method includes mechanical pulverization, airflow pulverization, and ball milling pulverization.

11. The preparation method of α-aluminum oxide nanoparticles according to claim 1, characterized in that, The second temperature is 700 - 1100°C.

12. The preparation method of the α-aluminum oxide particles according to claim 11, characterized in that, The second temperature is 800 - 1000°C.

13. α-alumina nanoparticles synthesized by the synthesis method according to any one of claims 1 - 12.

14. Disperse the α-alumina powder prepared by the preparation method of the α-alumina nanoparticles according to any one of claims 1 - 12 to obtain a nano-α-alumina dispersion.

15. The dispersion treatment according to claim 14 includes ball milling, sand milling, and high-speed shearing.

16. Use of the nano-α-alumina dispersion according to claim 15 for chemical mechanical polishing.

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