Method for regulating and controlling irregularity and morphology of SiO2 abrasive material through cations

Abstract

According to the method, tetraethyl orthosilicate is used as a silicon source, ammonia water is used as a catalyst, non-metal cations are used as a profile degree and morphology regulating agent, and in an alcohol-water system, the profile degree and morphology of the SiO2 abrasive are regulated and controlled by regulating and controlling the anisotropy of a silicon dioxide nucleation growth environment, so that the profile degree and morphology of the SiO2 abrasive are regulated and controlled. And the preparation of the silicon dioxide with adjustable special-shaped degree and shape is realized. Compared with a method for preparing special-shaped silicon dioxide from metal salt, the method has the advantages that the adopted non-metal cations have a larger concentration adjusting range in an alkaline environment in the silicon dioxide nucleation and growth process, and the special-shaped degree and morphology of silicon dioxide can be adjusted and controlled to a greater extent according to polishing requirements. Besides, the electronic-grade silicon wafer has extremely strict limitation on the concentration of metal ions, and no metal ions are introduced in the process of preparing the special-shaped silicon dioxide, so that the method has more advantages compared with a method for preparing the special-shaped silicon dioxide by using metal cations.

Description

Technical Field

[0001] The present invention belongs to the technical field of polishing materials, and particularly relates to a cation-regulated SiO 2 Methods for abrasive profile and morphology. Background Art

[0002] With the development of the electronic information age, the integrated circuit industry has shown a thriving development trend in terms of both production scale and market scale. Chemical mechanical polishing, as the only technology that can achieve global flattening, has been repeatedly used in the production and manufacturing of integrated circuits and is an indispensable key process. However, the emphasis on polishing before and after different processes is different, which puts forward more precise requirements on the performance of the polishing liquid. Abrasives are key components of polishing liquids, and their shape, particle size and other factors greatly affect the quality and efficiency of polishing. In the actual production process, if the morphology and particle size of the abrasive can be controlled, the corresponding abrasive can be used according to the specific needs of different processes, thereby greatly promoting the efficiency of the polishing process. However, although there are some methods for preparing special-shaped silica abrasives, there are no reports on simple and effective methods for controlling the special shape and morphology of silica. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention aims to provide a cation-regulated SiO 2 The method of abrasive profile and morphology aims to explore a preparation method that can more finely control the profile and morphology of silicon dioxide abrasive according to actual polishing needs. To this end, the present invention selects non-metallic cations with a larger concentration adjustment range in an alkaline environment as profile and morphology regulators to effectively control the anisotropy of its growth environment during the nucleation and growth of silicon dioxide. The experimental conditions required for the preparation process are mild and the operation method is also very simple. It is specifically achieved through the following technical solutions:

[0004] A cation-regulated SiO 2 The invention discloses a method for controlling the profile and morphology of abrasives. The method uses tetraethyl orthosilicate as a silicon source, ammonia water as a catalyst, and non-metallic cations as profile and morphology regulators. In an alcohol-water system, the anisotropy of the silica nucleation growth environment is controlled to achieve the preparation of silica with adjustable profile and morphology.

[0005] Furthermore, the method comprises the following steps:

[0006] 1) Ammonia water, deionized water and ethanol are mixed uniformly, and then a non-metallic cationic additive is added and stirred for a certain period of time to make it uniformly dispersed in the solution to prepare a mixed solution A;

[0007] 2) Tetraethyl orthosilicate and ethanol are mixed evenly to obtain a mixed solution B, and then the mixed solution B is quickly poured into the mixed solution A, and the mixture is continuously stirred. After a certain reaction time, a shaped silica sol is obtained.

[0008] Furthermore, in step 1), the non-metallic cationic additive includes but is not limited to hexadecyltrimethylammonium bromide and ammonium chloride.

[0009] Furthermore, in step 1), the volume ratio of ammonia water, deionized water and ethanol is 2-6:14:76-80.

[0010] Further, in step 2), the volume ratio of tetraethyl orthosilicate to ethanol is 1:25.

[0011] Furthermore, in step 2), the volume ratio of the mixed solution A to the mixed solution B is 1:1.

[0012] Furthermore, the molar ratio of tetraethyl orthosilicate to the non-metallic cationic additive is 25-300.

[0013] Furthermore, the degree of irregularity refers to the ratio of the radial length of a silica particle to the distance between the centers of two adjacent spheres in the particle, that is, a=r / d, where a is the degree of irregularity, r is the average radial length of the particle, and d is the average distance between the centers of two adjacent spheres in the particle.

[0014] The present invention introduces non-metallic cations to prepare non-spherical silica abrasives with adjustable morphology and shape. In a water-alcohol system, tetraethyl orthosilicate is used as a silicon source, ammonia water is used as an alkaline catalyst, and non-metallic cations are used to achieve anisotropic regulation of the nucleation growth environment of silica, and non-metallic silica with adjustable morphology and shape is successfully prepared. Compared with most metal cations that tend to precipitate in an alkaline environment, the non-metallic cations used in the present invention have a wider concentration adjustment range in the nucleation growth environment of silica, that is, the morphology and morphology of the silica abrasive can be regulated to a greater extent, so that silica abrasives that meet the requirements can be prepared according to the polishing requirements of different processes. In addition, the introduction of metal ions is not involved in the process of preparing silica abrasives in the present invention, and it is easier to achieve the strict restrictions on metal ion concentration of electronic-grade silicon wafers. In addition, compared with the method of preparing shaped silica abrasives by introducing silane coupling agents, the preparation process of the present invention is simpler and more environmentally friendly.

[0015] The present invention is improved on the basis of the Stober method. In a water-alcohol system, TEOS is used as a silicon source, ammonia water is used as a catalyst, and non-metallic cations are selected as a shape and morphology regulator to prepare a shaped silica with adjustable shape and morphology. Compared with the method of preparing shaped silica with metal salts, the non-metallic cations used in the present invention have a larger concentration adjustment range in the alkaline environment of the silica nucleation and growth process, that is, the shape and morphology of the silica can be regulated to a greater extent according to the polishing requirements. In addition, electronic-grade silicon wafers have extremely strict restrictions on the concentration of metal ions, and the present invention does not introduce any metal ions in the process of preparing shaped silica, which is more advantageous than the method of preparing shaped silica with metal cations. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Prepare a schematic diagram for the present invention;

[0017] Figure 2 This is an electron microscope image of the microscopic morphology of the irregular silicon dioxide prepared in Example 1;

[0018] Figure 3 This is an electron microscope image of the microscopic morphology of the irregular silicon dioxide prepared in Example 2;

[0019] Figure 4 This is an electron microscope image of the microscopic morphology of the irregular silicon dioxide prepared in Example 3;

[0020] Figure 5 This is an electron microscope image of the microscopic morphology of the irregular silicon dioxide prepared in Example 4;

[0021] Figure 6 This is an electron microscope image of the microscopic morphology of the irregular silicon dioxide prepared in Example 5. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings in order to better understand the technical solution.

[0023] The present invention discloses a cation-regulated SiO 2 A method for adjusting the profile and morphology of abrasives. The method uses tetraethyl orthosilicate as a silicon source, ammonia water as a catalyst, and non-metallic cations as a profile and morphology regulator. In an alcohol-water system, the anisotropy of the silica nucleation growth environment is adjusted to achieve the preparation of silica with adjustable profile and morphology. The preparation principle diagram is shown in FIG. Figure 1 shown.

[0024] In an alkaline environment, the hydroxyl groups attached to the surface of silica will ionize, leaving oxygen anions and forming a uniform negative electric field. By introducing cations, the uniform negative electric field on the surface of the silica core is destroyed, and its growth environment is changed from isotropic to anisotropic, thereby preparing heteromorphic silica. Furthermore, by changing the concentration of cations to control the degree of anisotropy of the silica nucleation growth environment, the heteromorphism and morphology of silica can be controlled.

[0025] Example 1

[0026] Weigh 2 ml of ammonia water, 14 ml of deionized water, and 80 ml of ethanol respectively and stir them evenly in beaker 1. Then add 0.033 g of CTAB into beaker 1 and stir for 5-10 minutes until the mixture is evenly dispersed.

[0027] Weigh 4 ml of TEOS and 100 ml of ethanol respectively into beaker 2, stir for 5-10 minutes, pour into beaker 1 at a certain speed, seal the mouth of the beaker with a plastic film, continue stirring at a speed of 400 rpm, and react for 20 hours to obtain a special-shaped silica sol.

[0028] The microscopic morphology of the irregular silicon dioxide particles prepared in this embodiment is shown in the electron microscope image. Figure 2 As shown, the particle size is 60-80 nm, the dispersion is good, the morphology is relatively uniform, and the overall shape is peanut and potato. According to calculation, the average shape degree of the irregular silicon dioxide particles prepared in this embodiment is about 0.61.

[0029] Example 2

[0030] Weigh 2 ml of ammonia water, 14 ml of deionized water, and 80 ml of ethanol respectively and stir them evenly in beaker 1. Then add 0.136 g of CTAB into beaker 1 and stir for 5-10 minutes until the mixture is evenly dispersed.

[0031] Weigh 4 ml of TEOS and 100 ml of ethanol respectively into beaker 2, stir for 5-10 minutes, pour into beaker 1 at a certain speed, seal the mouth of the beaker with a plastic film, continue stirring at a speed of 400 rpm, and react for 20 hours to obtain a special-shaped silica sol.

[0032] The microscopic morphology of the irregular silicon dioxide particles prepared in this embodiment is shown in the electron microscope image. Figure 3 As shown, the particle size is 80-90 nm, the dispersion is good, and the overall morphology is ellipsoidal and peanut-shaped. According to calculation, the average degree of irregularity of the irregular silicon dioxide particles prepared in this embodiment is about 0.64.

[0033] Example 3

[0034] Weigh 6 ml of ammonia water, 14 ml of deionized water, and 76 ml of ethanol respectively and stir them evenly in beaker 1. Then add 0.044 g of CTAB into beaker 1 and stir for 5-10 minutes until the mixture is evenly dispersed.

[0035] Weigh 4 ml of TEOS and 100 ml of ethanol respectively into beaker 2, stir for 5-10 minutes, pour into beaker 1 at a certain speed, seal the mouth of the beaker with a plastic film, continue stirring at a speed of 400 rpm, and react for 20 hours to obtain a special-shaped silica sol.

[0036] The microscopic morphology of the irregular silicon dioxide particles prepared in this embodiment is shown in the electron microscope image. Figure 4 As shown, the particle size is 200-300 nm, the dispersion is good, and the overall morphology is peanut-shaped. According to calculations, the average degree of irregularity of the irregular silicon dioxide particles prepared in this embodiment is about 0.55.

[0037] Example 4

[0038] Weigh 2 ml of ammonia water, 14 ml of deionized water, and 80 ml of ethanol respectively and stir them evenly in beaker 1. Then add 0.033 g of ammonium chloride into beaker 1 and stir for 5-10 minutes until the mixture is evenly dispersed.

[0039] Weigh 4 ml of TEOS and 100 ml of ethanol respectively into beaker 2, stir for 5-10 minutes, pour into beaker 1 at a certain speed, seal the mouth of the beaker with a plastic film, continue stirring at a speed of 400 rpm, and react for 20 hours to obtain a special-shaped silica sol.

[0040] The microscopic morphology of the irregular silicon dioxide particles prepared in this embodiment is shown in the electron microscope image. Figure 5 As shown, the particle size is 50-60 nm, the dispersion is good, and the overall morphology is a peanut shape and a three-sphere shape connected by triangles. According to calculations, the average degree of irregularity of the irregular silicon dioxide particles prepared in this embodiment is about 0.51.

[0041] Example 5

[0042] Weigh 2 ml of ammonia water, 14 ml of deionized water, and 80 ml of ethanol respectively and stir them evenly in beaker 1. Then add 0.136 g of ammonium chloride into beaker 1 and stir for 5-10 minutes until the mixture is evenly dispersed.

[0043] Weigh 4 ml of TEOS and 100 ml of ethanol respectively into beaker 2, stir for 5-10 minutes, pour into beaker 1 at a certain speed, seal the mouth of the beaker with a plastic film, continue stirring at a speed of 400 rpm, and react for 20 hours to obtain a special-shaped silica sol.

[0044] The microscopic morphology of the irregular silicon dioxide particles prepared in this embodiment is shown in the electron microscope image. Figure 6As shown, the particle size is 70-90 nm, the dispersion is good, and the overall morphology is peanut-shaped and some multi-ball agglomerates form a dried ginger-shaped. According to calculations, the average degree of irregularity of the irregular silicon dioxide particles prepared in this embodiment is about 0.54.

Claims

1. A method for regulating the shape and morphology of SiO2 abrasive by cations, characterized in that This method uses tetraethyl orthosilicate as a silicon source, ammonia water as a catalyst, and non-metallic cations as anisotropy and morphology regulators. In an alcohol-water system, the anisotropy of the silica nucleation growth environment is controlled to achieve the preparation of silica with adjustable anisotropy and morphology.

2. A method for regulating the shape and morphology of SiO2 abrasive by cations as claimed in claim 1, characterized in that The method comprises the following steps: 1) Ammonia water, deionized water and ethanol are mixed uniformly, and then a non-metallic cationic additive is added and stirred for a certain period of time to make it uniformly dispersed in the solution to prepare a mixed solution A; 2) Tetraethyl orthosilicate and ethanol are mixed evenly to obtain a mixed solution B, and then the mixed solution B is quickly poured into the mixed solution A, and the mixture is continuously stirred. After a certain reaction time, a shaped silica sol is obtained.

3. A method for regulating the shape and morphology of SiO2 abrasive by cations as claimed in claim 2, characterized in that In step 1), the non-metallic cationic additive includes but is not limited to hexadecyltrimethylammonium bromide and ammonium chloride.

4. A method for regulating the shape and morphology of SiO2 abrasive by cations as claimed in claim 2, characterized in that In step 1), the volume ratio of ammonia water, deionized water and ethanol is 2-6:14:76-80.

5. A method for regulating the shape and morphology of SiO2 abrasive by cations as claimed in claim 2, characterized in that In step 2), the volume ratio of tetraethyl orthosilicate to ethanol is 1:

25.

6. A method for regulating the shape and morphology of SiO2 abrasive by cations as claimed in claim 2, characterized in that In step 2), the volume ratio of mixed solution A to mixed solution B is 1:

1.

7. A method for regulating the shape and morphology of SiO2 abrasive by cations as claimed in claim 2, characterized in that The molar ratio of tetraethyl orthosilicate to the non-metallic cationic additive is 25-300.

8. The method for controlling the shape and morphology of SiO2 abrasive by cations according to claim 1, characterized in that: The degree of irregularity refers to the ratio of the radial length of a silica particle to the distance between the centers of two adjacent spheres in the particle, that is, a=r / d, where a is the degree of irregularity, r is the average radial length of the particle, and d is the average distance between the centers of two adjacent spheres in the particle.

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