KR102150945B1 - Polishing material including zirconia particle controlled crystallinity and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an abrasive including zirconia particles with controlled crystallinity and a method for producing the same. The abrasive according to the present invention can significantly improve performance and efficiency in the polishing and planarization process of a sapphire wafer, reduce surface defects, and achieve excellent flatness with a high material removal rate.
In addition, when polishing using the abrasive according to the present invention, a two-step CMP process can be simplified to a one-step process, thereby reducing investment and material cost.

Description

Abrasive material including zirconia particle controlled crystallinity and manufacturing method thereof

The present invention relates to an abrasive including zirconia particles with controlled crystallinity and a method for producing the same.

Sapphire is a single crystal form of aluminum oxide (Al ₂ O ₃ ) with excellent optical, mechanical and chemical properties. For example, sapphire maintains high strength even at high temperatures, has good thermal properties, excellent transparency, and excellent chemical stability, and has chip resistance, durability, scratch resistance, radiation resistance, and flexural strength at elevated temperature.

For extreme conditions such as those found in high temperature environments or toxic chemical environments, sapphire's unique properties make it a cost-effective solution for applications where long life and high performance are essential. Sapphire is used in a variety of electronic and optical components, test and analytical applications (e.g., NMR spectroscopy, thermo-optical temperature measurement, mass spectrometry, analysis of biological and chemical samples, sensor windows, forward-looking infrared vision devices (FLIR)). ), infrared spectroscopy), lamps and lamp envelopes (eg, electronic infrared countermeasures, ultraviolet sterilization and high-intensity lamps).

For engineers facing design challenges in the semiconductor manufacturing industry, sapphire is becoming increasingly the best material. For example, thanks to the properties that sapphire imparts, sapphire is characterized by plasma containment tubes, process gas injectors, thermocouple protection structures, viewports and sight windows, end effectors, and gas diffusion plates. , It is applied for substrates and wafers.

Sapphire has a rhombohedral-type structure, and is a material that is quite anisotropy with a property that is highly dependent on crystal orientation.

Sapphire wafers typically have a crystallographic axis, such as the C-plane (0001), also referred to as the zero degree plane, the A-plane 1120, also referred to as the 90 degree plane, the R-plane at 57.6 degrees from the C-plane ( 1102).

C-plane sapphire wafers are used to grow III-V and II-VI compounds (eg GaN) for blue LEDs and laser diodes. Moreover, C-plane sapphire is useful for infrared detector applications and optical systems.

Although sapphire offers a number of advantages due to its hardness and chemical resistance (resistance to chemical attack), polishing and flattening sapphire poses a number of challenges. Hard abrasives with high material removal rates are often required to provide an acceptable polishing rate. However, these abrasives can scratch or damage the surface of the sapphire. Soft, slow acting abrasives can be used to reduce the likelihood of scratching and damage, but the disadvantage of these abrasives is that often unacceptable time is required to achieve the desired level of surface polishing and planarization. will be.

Considering these and other defects in the prior art, it would be highly desirable to develop an improved abrasive that can minimize defects and flaws while providing rapid material removal rates.

Korean Patent Registration No. 1847266

An object of the present invention is to provide an abrasive that can significantly improve the performance and efficiency of a sapphire wafer polishing and planarization process.

Another object of the present invention is to provide an abrasive that can reduce investment and material cost by simplifying a zirconia-based chemical-mechanical planarization (CMP) process into a one-step process.

In order to achieve the above object, the present invention provides an abrasive including zirconia (ZrO ₂ ) particles having a Tetragonal crystal structure and an average particle diameter in the range of 3 to 15 nm in one embodiment.

In addition, in one embodiment, the present invention provides a polishing method including polishing a sapphire wafer that has been ground and wrapped with the abrasive.

In addition, the present invention includes the step of preparing zirconia particles by treating a mixture of 1.5 to 10 mol% of a dopant precursor and 90 to 98.5 mol% of a zirconia precursor at 120 to 500°C in an embodiment, and zirconia (ZrO ₂ ) The particles provide a method of manufacturing an abrasive that has an average particle diameter in the range of 3 to 15 nm.

The abrasive according to the present invention can significantly improve performance and efficiency in the polishing and planarization process of a sapphire wafer, reduce surface defects, and achieve excellent flatness with a high material removal rate.

In addition, when polishing using the abrasive according to the present invention, the two-step chemical-mechanical planarization (hereinafter'CMP') process can be simplified to a one-step process. Cost can be reduced.

1 is a view schematically showing a conventional method of polishing a sapphire wafer.
2 is a diagram schematically showing a method of polishing a sapphire wafer using the abrasive of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description.

However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

In the present invention, terms such as "comprises" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

In addition, the accompanying drawings in the present invention should be understood as being enlarged or reduced for convenience of description.

Abrasive

In one embodiment, the present invention provides an abrasive including zirconia (ZrO ₂ ) particles having a tetragonal crystal structure and an average particle diameter in the range of 3 to 15 nm.

Specifically, the average diameter of the zirconia (ZrO ₂ ) particles may be in the range of 3 to 15 nm, specifically, 5 to 15 nm, 5 to 10 nm, 5 to 8 nm, 3 to 12 nm, 3 to 10 nm or It may be in the range of 3 to 8 nm.

Zirconia (ZrO ₂ ) particles are one of yttria (Y ₂ 0 ₃ ), calcium oxide (CaO), magnesia (MgO), alumina (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ) and ceria (CeO ₂ ) It may be more doped.

Specifically, pure zirconia (ZrO ₂ ) particles are made of monoclinic crystals, but the zirconia particles are doped with yttria, calcium oxide, magnesia, etc. to control the crystallinity of the particles with tetragonal crystals. By doing so, stability of the zirconia particles can be imparted. In particular, since a phase shift does not occur due to a monoclinic crystal at room temperature (25°C), an increase in the volume of particles does not occur, and the crystal may exist as a stable tetragonal crystal.

The abrasive may be a water dispersion slurry formulation.

An abrasive made of an aqueous slurry formulation may have a surface roughness (Ra) of 3.3 or less. Specifically, the abrasive made of the aqueous slurry formulation may have a surface roughness (Ra) of 2.0 to 3.3 or 2.2 to 3.2.

An abrasive made of an aqueous dispersion slurry formulation may have a pH of 11.5 or higher. Specifically, the abrasive made of the slurry formulation may have a pH in the range of 11.5 to 13, and specifically, 11.5 to 12.8 or 12 to 12.8.

The abrasive according to the present invention may be for polishing a sapphire wafer.

Polishing method

1 shows the CMP process of the existing sapphire, in the conventional CMP process, after pre-polishing with diamond slurry, the final polishing process using silica is applied, but the pre-polishing with diamond slurry is performed. In this case, cost competitiveness is lowered by diamond, and there is a difficulty in securing surface quality by using silica.

In order to solve the above problem, the present invention can secure price competitiveness by not performing a preliminary polishing step, and by using an abrasive slurry containing particles other than silica, excellent quality can be secured on the silica wafer polishing surface. .

Specifically, an embodiment of the present invention provides a polishing method including polishing a sapphire wafer that has been ground and wrapped with the abrasive.

When polishing a sapphire wafer that has been ground and wrapped with the abrasive, a material removal rate (MRR) applying the following Equation 1 is 4400 Å/min or more.

[Equation 1]

In Equation 1, the weight before polishing (g), the weight after polishing (g), density (D) and cross-sectional area (A) are for a sapphire wafer.

Specifically, the material removal rate (MRR) of the polishing method of the present invention may be in the range of 4400 to 6500 Å/min.

Manufacturing method of abrasive

In an embodiment of the present invention, comprising the step of preparing zirconia particles by treating a mixture of 1.5 to 10 mol% of a dopant precursor and 90 to 98.5 mol% of a zirconia precursor at 120 to 500°C, and zirconia (ZrO ₂ ) The particles have an average particle diameter in the range of 3 to 15 nm to provide a method for producing an abrasive.

Specifically, a mixture of 1.5 to 10 mol% of a dopant precursor and 90 to 98.5 mol% of a zirconia precursor may be obtained by mixing 2 to 10 mol% of a dopant precursor and 90 to 98 mol% of a zirconia precursor.

Specifically, when the content of the yttria precursor and the zirconia precursor is less than 1.5 mol%, the density decreases and the crystallinity and polishing rate decrease, and when the content of the yttria precursor and the zirconia precursor is greater than 10 mol%, the density increases, resulting in a problem of increasing the crystallinity and polishing rate . Specifically, the mixture of the dopant precursor and the zirconia precursor is 2 to 4 mol% of the dopant precursor and 96 to 98 mol% of the zirconia precursor, 4 to 6 mol% of the dopant precursor and 94 to 96 mol% of the zirconia precursor, 6 to 10 mol% dopant precursor and 90 to 94 mol% zirconia precursor, 6 to 8 mol% dopant precursor and 92 to 94 mol% zirconia precursor, 8 to 10 mol% dopant precursor 90 to 92 mol% zirconia precursor, 4-10 mol% of dopant precursor 90-96 mol% of zirconia precursor, 6-10 mol% of dopant precursor 90-94 mol% of zirconia precursor, 4-8 mol% of dopant precursor 92-96 mol% of zirconia precursor Alternatively, it may be obtained by mixing 2 to 6 mol% of a dopant precursor of 94 to 98 mol% of a zirconia precursor.

Specifically, the average diameter of the zirconia (ZrO ₂ ) particles may be in the range of 3 to 15 nm, specifically, 5 to 15 nm, 5 to 10 nm, 5 to 8 nm, 3 to 12 nm, 3 to 10 nm or It may be in the range of 3 to 8 nm.

Specifically, when processing at a temperature of less than 120°C, the average diameter of the dopant-doped zirconia (ZrO ₂ ) particles increases, and when the sapphire wafer is polished using this, the material removal rate (MRR) decreases. , After polishing, the polishing surface of the sapphire wafer has a problem that the surface roughness increases.

In addition, in the step of preparing zirconia particles by treating a mixture of 1.5 to 10 mol% of a dopant precursor and 90 to 98.5 mol% of a zirconia precursor at 120 to 400°C, 1.5 to 5 mol% of a dopant precursor and 95 to 98.5 mol A mixture of% zirconia precursors can be treated at 250 to 400°C to produce zirconia particles.

In addition, in the step of preparing zirconia particles by treating a mixture of 1.5 to 10 mol% of a dopant precursor and 90 to 98.5 mol% of a zirconia precursor at 120 to 400°C, 1.5 to 10 mol% of a dopant precursor and 90 to 98.5 mol A mixture of% zirconia precursors may be treated at 120 to 500° C. and 10 to 30 atm for 2 to 10 hours to produce zirconia particles.

In addition, the dopant precursor is yttria (Y ₂ 0 ₃ ) precursor, calcium oxide (CaO) precursor, magnesia (MgO) precursor, alumina (Al ₂ O ₃ ) precursor, hafnium oxide (HfO ₂ ) precursor and ceria (CeO ₂ ) It may be one or more of the precursors.

Specifically, the yttria precursor may be at least one of Y(OH) ₃ , YCl ₃ , YCl ₃ ·6H ₂ O, and YF ₃ .

In addition, the zirconia precursor is Zr(CH ₂ COO) ₂ , ZrO(NO ₃ ) ₂ , ZrOCl ₂ ·8H ₂ O, Zr(OH) ₄ ·xH ₂ O, ZrSO ₄ ·4H ₂ O, ZrO ₂ ·P ₂ O ₅ , and Zr(CH ₃ -CH ₂ COO) _{2 It} may be one or more.

Specifically, the zirconia (ZrO ₂ ) particles may include tetragonal crystals.

Specifically, pure zirconia particles are made of monoclinic crystals, but dopant is doped on the surface of zirconia particles, and by controlling the crystallinity of the particles with tetragonal crystals, stability of the zirconia particles can be imparted. . In particular, since a phase shift does not occur due to a monoclinic crystal at room temperature (25°C), an increase in the volume of particles does not occur, and the crystal may exist as a stable tetragonal crystal.

When polishing the surface of a sapphire wafer with an abrasive containing particles controlled by such tetragonal crystals, there is no need to perform a preliminary polishing step, and even if it is a one-step process, the surface roughness of the polishing surface after polishing can be significantly reduced. There is an advantage to be able to.

In addition, after the step of preparing zirconia particles by treating a mixture of 1.5 to 10 mol% of a dopant precursor and 90 to 98.5 mol% of a zirconia precursor at 120 to 500°C, the zirconia particles are dispersed in water to prepare an abrasive in a slurry formulation. It may include the step of.

The abrasive in the slurry formulation in which the zirconia particles are dispersed may include 10 to 30% by weight of zirconia particles and 70 to 90% by weight of water. Specifically, the abrasive in the slurry formulation in which the zirconia particles are dispersed may include 15 to 25% by weight of zirconia particles and 75 to 85% by weight of water or 18 to 22% by weight of zirconia particles and 78 to 82% by weight of water.

The slurry formulation of the abrasive may have a surface roughness (Ra) of 3.3 or less, and specifically, a surface roughness (Ra) of 2.0 to 3.3 or 2.2 to 3.2.

The abrasive of the aqueous dispersion slurry formulation may have a pH of 11.5 or higher, and specifically, may be in the range of 11.5 to 12.8 or 12 to 12.8.

Hereinafter, the present invention will be described in more detail by examples and experimental examples.

However, the following examples and experimental examples are merely illustrative of the present invention, and the contents of the present invention are not limited to the following examples and experimental examples.

Synthesis Examples 1 to 5.

1. Synthesis of Zirconia Particles

A zirconia precursor solution in which ZrOCl ₂ ·8H ₂ O was dissolved in deionized water was stirred at room temperature for 1 hour.

Thereafter, the prepared ZrOCl ₂ ·8H ₂ O precursor solution was mixed and stirred at room temperature for 1 hour.

Transfer the mixed solution of ZrOCl ₂ ·8H ₂ O and YCl ₃ precursor to a three-necked flask, and slowly drop an ammonium hydroxide solution at a rate of 0.1 ml/min using a metering pump at a stirring speed of 500 rpm or higher to obtain a gel precipitate. After the gel precipitate was transferred to a hydrothermal reactor, zirconia particles were synthesized by heat treatment for 6 hours at 25 atm at the temperature shown in Table 1 (No. 1 to No. 5) below.

2. Synthesis of abrasive slurry

Above No. 1 to No. 20% by weight of the zirconia particles synthesized under the conditions of 5 were dispersed in 80% by weight of ultrapure water, and potassium hydroxide was added while stirring to adjust the pH as shown in Table 1 below, and then ball milling was performed for 24 hours. The obtained slurry was filtered through a 1 micron filter to prepare an abrasive slurry.

YCl ₃ content
(Unit: mol%) ZrOCl ₂ · 8H ₂ O content
(Unit: mol%) Process temperature
(℃) Slurry pH No.1 0 100 100 11.6 No.2 0 100 150 11.9 No.3 0 100 200 12.3 No.4 0 100 300 12.5 No.5 0 100 400 12.9

Synthesis Examples 6 to 10.

1. Synthesis of Zirconia Particles

The precursor solutions in which the ZrOCl ₂ ·8H ₂ O and YCl ₃ precursors were each dissolved in deionized water according to the molar ratios described in Table 2 (No. 6 to No. 10) were stirred at room temperature for 1 hour.

Thereafter, the ZrOCl ₂ ·8H ₂ O and YCl ₃ precursor solutions prepared according to the molar ratio were mixed and stirred at room temperature for 1 hour.

Transfer the ZrOCl ₂ · 8H ₂ O and YCl ₃ precursor mixed solution to a three-necked flask, and slowly drop the ammonium hydroxide solution at a rate of 0.1 ml/min using a metering pump at a stirring speed of 500 rpm or higher to obtain a gel precipitate. After the gel precipitate was transferred to a hydrothermal reactor, zirconia particles were synthesized by heat treatment for 6 hours at 25 atm at the temperature shown in Table 2 (No. 6 to No. 10) below.

2. Synthesis of abrasive slurry

Above No. 6 to No. After dispersing 20% by weight of zirconia particles synthesized under 10 conditions in 80% by weight of ultrapure water, adding potassium hydroxide while stirring to adjust the pH as shown in Table 1 below, ball milling was performed for 24 hours. The obtained slurry was filtered through a 1 micron filter to prepare an abrasive slurry.

YCl ₃ content
(Unit: mol%) ZrOCl ₂ · 8H ₂ O content
(Unit: mol%) Process temperature
(℃) Slurry pH No.6 2 98 100 11.4 No.7 2 98 150 11.9 No.8 2 98 200 12.1 No.9 2 98 300 12.6 No.10 2 98 400 12.8

Synthesis Examples 11 to 15.

Except for using the conditions of Table 3 below, the abrasive slurry was synthesized under the same conditions as in Synthesis Examples 6 to 10.

YCl ₃ content
(Unit: mol%) ZrOCl ₂ · 8H ₂ O content
(Unit: mol%) Process temperature
(℃) Slurry pH No.11 4 96 100 11.8 No.12 4 96 150 11.9 No.13 4 96 200 12.3 No.14 4 96 300 12.7 No.15 4 96 400 13.1

Synthesis Examples 16 to 20.

Except for using the conditions of Table 4 below, the abrasive slurry was synthesized under the same conditions as in Synthesis Examples 6 to 10.

YCl ₃ content
(Unit: mol%) ZrOCl ₂ · 8H ₂ O content
(Unit: mol%) Process temperature
(℃) Slurry pH No.16 6 94 100 11.6 No.17 6 94 150 11.9 No.18 6 94 200 12.5 No.19 6 94 300 12.9 No.20 6 94 400 13.3

Synthesis Examples 21 to 25.

Except for using the conditions of Table 5 below, the abrasive slurry was synthesized under the same conditions as in Synthesis Examples 6 to 10.

YCl ₃ content
(Unit: mol%) ZrOCl ₂ · 8H ₂ O content
(Unit: mol%) Process temperature
(℃) Slurry pH No.21 8 92 100 11.7 No.22 8 92 150 11.9 No.23 8 92 200 12.3 No.24 8 92 300 12.6 No.25 8 92 400 13.1

Synthesis Examples 26 to 30.

Except for using the conditions of Table 6 below, the abrasive slurry was synthesized under the same conditions as in Synthesis Examples 6 to 10.

YCl ₃ content
(Unit: mol%) ZrOCl ₂ · 8H ₂ O content
(Unit: mol%) Process temperature
(℃) Slurry pH No.26 10 90 100 11.8 No.27 10 90 150 12 No.28 10 90 200 12.2 No.29 10 90 300 12.7 No.30 10 90 400 13

Comparative Examples 1 to 5.

Using a polishing device (device name: CETR CP-4, manufacturer: Bruker Corporation) and polishing pad (product name: SUBA 600, manufacturer: Dow Chemical), platen pressure 7 psi, head rotation Polishing of the silicon wafer was performed using the abrasive slurry shown in Table 7 below under conditions of a number of 100 rpm, a platen rotation speed of 100 rpm, and a flow rate of 80 ml/min of the abrasive slurry according to Synthesis Examples 1 to 5 I did.

Abrasive slurry Comparative Example 1 No.1 (Synthesis Example 1) Comparative Example 2 No.2 (Synthesis Example 2) Comparative Example 3 No.3 (Synthesis Example 3) Comparative Example 4 No.4 (Synthesis Example 4) Comparative Example 5 No.5 (Synthesis Example 5)

Comparative Examples 6 to 15.

A silicon wafer was polished under the same conditions as in Comparative Examples 1 to 5, except that the conditions of Table 8 were used.

Abrasive slurry Comparative Example 6 No.6 (Synthesis Example 6) Comparative Example 7 No. 7 (Synthesis Example 7) Comparative Example 8 No.8 (Synthesis Example 8) Comparative Example 9 No.9 (Synthesis Example 9) Comparative Example 10 No. 11 (Synthesis Example 11) Comparative Example 11 No.12 (Synthesis Example 12) Comparative Example 12 No. 13 (Synthesis Example 13) Comparative Example 13 No. 16 (Synthesis Example 16) Comparative Example 14 No. 21 (Synthesis Example 21) Comparative Example 15 No. 26 (Synthesis Example 26)

Examples 1 to 15.

A silicon wafer was polished under the same conditions as Comparative Examples 1 to 5, except that the conditions of Table 9 were used.

Abrasive slurry Example 1 No.10 (Synthesis Example 10) Example 2 No. 14 (Synthesis Example 14) Example 3 No.15 (Synthesis Example 15) Example 4 No. 17 (Synthesis Example 17) Example 5 No.18 (Synthesis Example 18) Example 6 No. 19 (Synthesis Example 19) Example 7 No. 20 (Synthesis Example 20) Example 8 No.22 (Synthesis Example 22) Example 9 No. 23 (Synthesis Example 23) Example 10 No. 24 (Synthesis Example 24) Example 11 No.25 (Synthesis Example 25) Example 12 No. 27 (Synthesis Example 27) Example 13 No. 28 (Synthesis Example 28) Example 14 No. 29 (Synthesis Example 29) Example 15 No.30 (Synthesis Example 30)

Experimental Example 1. Analysis of Zirconia Particles in Abrasive Slurry

The average particle diameter of the abrasive particles contained in the abrasive slurry according to Synthesis Examples 1 to 30 was measured by electron microscopy (device name: TEM, Transmission Electron Microscopy, JEOL), and crystallographic analysis was performed.

Average particle diameter (nm) Monoclinic structure Tetragonal structure No.1 80.6 O - No.2 50.3 O - No.3 35.2 O - No.4 25.1 O - No.5 20.8 O -

Average particle diameter (nm) Monoclinic structure Tetragonal structure No.6 60.7 O - No.7 23.1 O O No.8 17.5 O O No.9 12.3 O O No.10 8.4 - O

Average particle diameter (nm) Monoclinic structure Tetragonal structure No.11 50.3 O - No.12 11.7 O O No.13 10.2 O O No.14 8.6 - O No.15 7.5 - O

Average particle diameter (nm) Monoclinic structure Tetragonal structure No.16 45.9 O - No.17 10.8 - O No.18 8.6 - O No.19 7.3 - O No.20 6.9 - O

Average particle diameter (nm) Monoclinic structure Tetragonal structure No.21 40.1 O - No.22 10.3 - O No.23 8.3 - O No.24 7.7 - O No.25 6.1 - O

Average particle diameter (nm) Monoclinic structure Tetragonal structure No.26 35.2 O - No.27 10.1 - O No.28 8.8 - O No.29 6.7 - O No.30 5.2 - O

Referring to Tables 10 to 15, since monoclinic crystals have a relatively large volume compared to tetragonal crystals, particles composed of only monoclinic crystals have a relatively high average particle diameter, When monoclinic crystals and tetragonal crystals were mixed, the average particle diameter was higher than that of particles composed of only tetragonal crystals. This affects the material removal rate and surface roughness, which will be described later, and it can be seen that it is an important factor to control the crystallinity of the particles with a tetragonal crystal, and control the crystallinity of the particles to have a tetragonal crystal. By doing so, the average particle diameter of the particles could be reduced to a range of about 5 to 11 nm.

Experimental Example 2. Material removal rate analysis

The 2-inch disk polished by the abrasive slurry was immersed in a solution of distilled water and ethanol, and then ultrasonicated for 30 minutes and dried at 80° C. for 1 hour.

Thereafter, the material removal rate of the sapphire wafer to which Equation 1 was applied was measured before and after polishing using a precision balance (±0.0001 g), and the material removal rate was calculated through Equation 1 below. Here, the density (D) of the sapphire wafer was 4.1 g/cm ^3, and the cross-sectional area (A) of the sapphire 2-inch wafer was 20.3 cm ² .

[Equation 1]

In Equation 1, the weight before polishing (g), the weight after polishing (g), density (D) and cross-sectional area (A) are for a sapphire wafer.

The sapphire wafer was washed with distilled water for 30 minutes and acetone for 30 minutes and dried at 60° C. for 1 hour, and the results are shown in Tables 16 and 17 below.

Material removal rate (MRR)(Å/min) Comparative Example 1 821.8 Comparative Example 2 1040.2 Comparative Example 3 1243.5 Comparative Example 4 1472.6 Comparative Example 5 1617.6 Comparative Example 6 946.9 Comparative Example 7 1688.5 Comparative Example 8 2292.6 Comparative Example 9 3576.1 Comparative Example 10 1040.2 Comparative Example 11 2588.2 Comparative Example 12 3696.0 Comparative Example 13 1088.9 Comparative Example 14 1165.0 Comparative Example 15 1243.5

Material removal rate (MRR)(Å/min) Example 1 5091.0 Example 2 5031.4 Example 3 5387.8 Example 4 4489.8 Example 5 5031.4 Example 6 5461.1 Example 7 5617.2 Example 8 4597.5 Example 9 5121.6 Example 10 5317.4 Example 11 5974.2 Example 12 4642.8 Example 13 4973.9 Example 14 5700.4 Example 15 6470.5

Referring to Tables 16 and 17, when polishing a sapphire wafer according to Examples 1 to 15, the material removal rate was from a minimum of 4489.8 Å/min to a maximum of 6470.5 Å/min, which improved the material removal rate (MRR), which was a comparative example. It was confirmed that process time and cost can be reduced compared to 1 to 15.

Experimental Example 3. Analysis of surface roughness of polished sapphire wafer

The surface roughness (Ra) of the sapphire wafer polished surface was measured using an atomic force microscope (product name: D-3100 (AFM, Atomic Force Microscopy, manufacturer: Veeco, USA), and the results are shown in Tables 18 and 19 below. .

Ra Comparative Example 1 8.9 Comparative Example 2 7.1 Comparative Example 3 5.9 Comparative Example 4 5.0 Comparative Example 5 4.5 Comparative Example 6 7.8 Comparative Example 7 4.7 Comparative Example 8 4.1 Comparative Example 9 3.4 Comparative Example 10 7.1 Comparative Example 11 3.3 Comparative Example 12 3.1 Comparative Example 13 6.7 Comparative Example 14 6.3 Comparative Example 15 5.9

Ra Example 1 2.8 Example 2 2.8 Example 3 2.6 Example 4 3.2 Example 5 2.8 Example 6 2.6 Example 7 2.5 Example 8 3.1 Example 9 2.8 Example 10 2.7 Example 11 2.4 Example 12 3.1 Example 13 2.9 Example 14 2.5 Example 15 2.2

Referring to Tables 18 and 19, when polishing using zirconia particles not doped with yttria (Comparative Examples 1 to 5), compared to the surface roughness of 4.5 to 8.9, the abrasive slurry of Examples 1 to 15 was used. When doing so, it was confirmed that the surface roughness of the polished silicon wafer was remarkably improved. Further, even if the yttria content gradually increased, when the sapphire wafer was polished with an abrasive slurry containing particles synthesized at a temperature of 100°C, the surface roughness of the polished sapphire wafer was slightly decreased. Therefore, it was confirmed that it is preferable to prepare the particles under conditions of 150 to 400°C.

Claims (15)

It is made of a tetragonal crystal structure, has an average particle diameter in the range of 3 to 15 nm, yttria (Y ₂ 0 ₃ ), calcium oxide (CaO), magnesia (MgO), alumina (Al ₂ O ₃ ) , Hafnium oxide (HfO ₂ ) and ceria (CeO ₂ ) Abrasives containing zirconia (ZrO ₂ ) particles doped with one or more of. delete The method of claim 1,
The abrasive is an aqueous dispersion slurry formulation. The method of claim 3,
An abrasive material having a surface roughness (Ra) of 3.3 or less. The method of claim 3,
An abrasive with a pH of 11.5 or higher. The method of claim 1,
The abrasive is for polishing a sapphire wafer. A polishing method comprising polishing a grinded and wrapped sapphire wafer with the abrasive according to claim 1. The method of claim 7,
When polishing a sapphire wafer that has been ground and wrapped with the abrasive according to claim 1, the material removal rate (MRR) by applying the following Equation 1 is 4400 Å/min or more:
[Equation 1]

In Equation 1, the weight before polishing (g), the weight after polishing (g), density (D) and cross-sectional area (A) are for a sapphire wafer. Treating a mixture of a dopant precursor of 1.5 to 10 mol% and a zirconia precursor of 90 to 98.5 mol% at 120 to 500°C to prepare zirconia particles,
When the mixture is a mixture of 6 to 10 mol% of a dopant precursor and 90 to 94 mol% of a zirconia precursor, heat treatment at 120 to 500°C,
When the mixture is a mixture of 4 to 6 mol% of a dopant precursor and 94 to 96 mol% of a zirconia precursor, heat treatment at 250 to 500 °C,
When the mixture is a mixture of 1.5 to 4 mol% of a dopant precursor and 96 to 98.5 mol% of a zirconia precursor, heat treatment at 400 to 500 °C,
Zirconia (ZrO ₂ ) particles have an average particle diameter in the range of 3 to 15 nm. delete The method of claim 9,
Dopant precursors are yttria (Y ₂ 0 ₃ ) precursor, calcium oxide (CaO) precursor, magnesia (MgO) precursor, alumina (Al ₂ O ₃ ) precursor, hafnium oxide (HfO ₂ ) precursor and ceria (CeO ₂ ) precursor. A method for producing an abrasive that is one or more. The method of claim 9,
Zirconia precursors are Zr(CH ₂ COO) ₂ , ZrO(NO ₃ ) ₂ , ZrOCl ₂ ·8H ₂ O, Zr(OH) ₄ ·xH ₂ O, ZrSO ₄ ·4H ₂ O, ZrO ₂ ·P ₂ O ₅ , And Zr(CH ₃ -CH ₂ COO) ₂ of one or more of the method for producing an abrasive. The method of claim 9,
After the step of preparing zirconia particles by treating a mixture of 1.5 to 10 mol% of a dopant precursor and 90 to 98.5 mol% of a zirconia precursor at 120 to 500°C,
A method of manufacturing an abrasive comprising the step of preparing an abrasive in a slurry form by dispersing zirconia particles in water. The method of claim 13,
The slurry formulation of the abrasive has a surface roughness (Ra) of 3.3 or less. The method of claim 13,
The aqueous dispersion slurry formulation of the abrasive is a method of manufacturing an abrasive having a pH of 11.5 or higher.

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