Concentrated solution of ITO glass polishing liquid and preparation method thereof

Abstract

The application provides an ITO glass polishing liquid concentrate and a preparation method thereof, according to the weight component, the polishing liquid concentrate comprises the following components: alumina slurry 30wt%-60wt%, inorganic salt 0.1wt%-5wt%, complexing agent 0.001wt%-1wt%, bactericide 0.001wt%-0.1wt%, and the balance is water; the solid content of the alumina slurry is 20wt%-50wt%, and the alumina slurry further comprises a suspending agent and an alkali, and the alkali is used for adjusting the pH of the polishing liquid concentrate to 11.5-13. The polishing liquid concentrate of the application is diluted by 5 times for ITO glass polishing, and the polishing rate can reach 40-45nm / min, meanwhile, the surface of the ITO glass after polishing is not scratched, the surface roughness can be reduced to within 0.6nm, and the haze can reach ≤0.5%, so that the polishing rate and the surface quality are considered.

Description

Technical Field

[0001] This invention relates to the field of polishing slurry technology, and in particular to an ITO glass polishing slurry concentrate and its preparation method. Background Technology

[0002] Transparent conductive oxide glass (ITO glass) is a basic optoelectronic material made by depositing a layer of indium tin oxide (ITO) conductive film onto sodium-calcium-based or borosilicate-based glass substrates using methods such as magnetron sputtering. This material possesses both excellent optical transmittance and good electrical conductivity, and is therefore widely used in flat panel displays and touchscreens such as touchscreens, liquid crystal displays (LCDs), organic light-emitting diodes (OLEDs), and electronic paper. In recent years, with the development of intelligent and electric vehicles, ITO glass has also been increasingly used in key optical components of automotive touchscreen displays, intelligent dimming sunroofs, anti-fog and defrosting windows, and head-up display (HUD) systems, becoming one of the core materials for improving the driving experience and the quality of human-vehicle interaction.

[0003] In the preparation and subsequent processing of ITO glass, chemical mechanical polishing (CMP) is often required to ensure atomic-level flatness of the conductive film surface, remove oxide layers or microparticle contaminants generated in previous processes, and meet the stringent cleanliness requirements of subsequent microelectronic lithography processes. The polishing slurry, as a core consumable in this process, directly determines the final quality of the ITO glass. To maintain the polishing rate, existing polishing slurries typically use large-diameter abrasive particles (such as cerium oxide and aluminum oxide). However, these particles easily cause microscopic mechanical damage such as scratches and pits on the ITO film surface during polishing, disrupting the conductive network and leading to a decrease in yield. On the other hand, using small-diameter abrasive particles results in low polishing efficiency, making it impossible to simultaneously achieve a high polishing rate and the surface quality of the polished glass. Furthermore, existing polishing slurries generally contain high levels of metallic impurity ions (such as sodium, calcium, iron, and copper ions). During polishing, these ions can enter the ITO film through surface adsorption or grain boundary diffusion, leading to abnormally high local resistance, deterioration of conductivity uniformity, and accelerated electrochemical corrosion of the ITO material, significantly shortening device lifespan.

[0004] More importantly, for high-end applications such as automotive glass, the existing polishing slurries result in excessively high haze in ITO glass, failing to achieve an "ultra-clear" effect. While the haze value of ITO glass polished with existing technology can meet the national standard requirement of ≤5%, this haze is still relatively high. On in-vehicle touchscreens, this can cause the image to appear washed out and the contrast to drop significantly in bright light. In smart dimming sunroofs or HUD systems, high haze can cause stray light scattering, resulting in blurred images, ghosting, and glare, directly threatening driving safety. Therefore, existing polishing slurries are insufficient to meet the ultra-low haze standards of less than 0.8% commonly required in the high-end automotive market, or even the ≤0.5% standard required for AR-HUD modules.

[0005] In summary, developing a new polishing fluid that combines high removal efficiency, low scratch damage, low impurity metal ion content, and enables ITO glass to achieve ultra-clear haze standards (haze ≤ 0.5%) is of significant technical and industrial value for expanding the application of ITO glass in automotive intelligence and high-end display fields, and for solving the performance degradation and safety risks caused by excessive haze and ion contamination in current automotive optical systems. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an ITO glass polishing slurry concentrate and its preparation method, which solves the problems of poor polishing efficiency, easy scratching of the ITO layer, and excessive haze of the polished ITO glass that cannot achieve the "ultra-clear" effect.

[0007] To achieve the above and other related objectives, the present invention provides an ITO glass polishing slurry concentrate and a method for preparing the same.

[0008] The first aspect of this invention provides an ITO glass polishing slurry concentrate, which, by weight, comprises the following components: 30wt%-60wt% alumina slurry, 0.1wt%-5wt% inorganic salt, 0.001wt%-1wt% complexing agent, 0.001wt%-0.1wt% bactericide, and the balance being water; the alumina slurry has a solid content of 20wt%-50wt%, and the alumina slurry further comprises a suspending agent and an alkali, wherein the alkali is used to adjust the pH of the polishing slurry concentrate to ≥11.5.

[0009] To balance the polishing rate and the surface quality of the ITO glass, the mass fraction of alumina slurry in the polishing slurry concentrate is preferably 40wt%-60wt%; for example, it can be 40wt%, 45wt%, 50wt%, 55wt%, or 60wt%.

[0010] More preferably, the mass fraction of alumina slurry in the polishing slurry concentrate is 45wt%-55wt%.

[0011] To balance the polishing rate and the surface quality of ITO glass, the inorganic salt content in the polishing slurry concentrate is preferably 0.5wt%-5wt%; for example, it can be 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, 2.5wt%, 3.0wt%, 3.5wt%, 4.0wt%, 4.5wt%, or 5wt%.

[0012] More preferably, the mass fraction of inorganic salts in the polishing slurry concentrate is 1wt%-3wt%.

[0013] The addition of inorganic salts can increase the polishing rate of the polishing slurry. By adjusting the ionic strength of the polishing slurry, the chemical reaction rate between the polishing slurry and the ITO glass surface can be changed, thereby accelerating the polishing process.

[0014] Preferably, the inorganic salt is potassium chloride.

[0015] To reduce the content of impurity metal ions in the polishing slurry concentrate while balancing the polishing rate and the surface quality of the ITO glass, the mass fraction of the complexing agent in the polishing slurry concentrate is preferably 0.01wt%-1wt%; for example, it can be 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, 0.1wt%, 0.2wt%, 0.5wt%, 0.8wt%, or 1wt%.

[0016] More preferably, the mass fraction of the complexing agent in the polishing slurry concentrate is 0.02wt%-0.5wt%.

[0017] The addition of complexing agents can complex all metal ions in the solution except for K and Al, reduce the metal ion content in the polishing solution, and prevent other metal ions besides K and Al from contacting the ITO glass surface during the polishing process, thus affecting the conductivity and haze of the ITO glass.

[0018] In order to achieve effective sterilization without causing side reactions with other components in the polishing liquid concentrate, the bactericide preferably has a mass fraction of 0.002wt%-0.008wt%; for example, it can be 0.002wt%, 0.005wt%, 0.006wt%, or 0.008wt%.

[0019] Preferably, the pH of the polishing slurry concentrate is 11.5-14.

[0020] More preferably, the pH of the polishing slurry concentrate is 12-13.

[0021] The main components of ITO are indium oxide (In₂O₃) and tin oxide (SnO₂), both of which react with high concentrations of OH radicals in a strongly alkaline environment. - The reaction generates soluble indium and stannate ions, which corrode and soften the ITO surface, creating a chemically reacted layer that is easily removed by mechanical grinding. The higher the pH, the greater the OH⁻ concentration and the faster the chemical etching rate. However, to ensure the surface quality after polishing, the pH value cannot be too high to prevent excessive corrosion that could damage the surface quality.

[0022] In order to simultaneously consider the polishing rate and the surface quality after polishing, the solid content of the alumina slurry is preferably 30wt%-50wt%; for example, it can be 30wt%, 35wt%, 40wt%, 45wt%, or 50wt%.

[0023] More preferably, the solid content of the alumina slurry is 35wt%-45wt%.

[0024] Too low an alumina concentration in the alumina slurry will result in a significant decrease in the polishing rate, while too high an alumina concentration will cause some particles to fail to suspend, resulting in particle stratification and deposition.

[0025] Preferably, the suspending agent is xanthan gum.

[0026] Preferably, the xanthan gum has a viscosity range of 1000-2000 cP at 25°C; for example, it can be 1000 cP, 1200 cP, 1400 cP, 1500 cP, 1600 cP, 1800 cP, or 2000 cP.

[0027] Preferably, the amount of xanthan gum added is 0.001wt%-0.1wt% based on the total weight of the alumina slurry.

[0028] More preferably, the amount of xanthan gum added is 0.01wt%-0.1wt% based on the total weight of the alumina slurry; for example, it can be 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, or 0.1wt%.

[0029] More preferably, the amount of xanthan gum added is 0.01wt%-0.05wt% based on the total weight of the alumina slurry.

[0030] If the amount of suspending agent added is too small, the alumina will not be able to suspend; if the amount added is too large, the polishing slurry will be too viscous and affect polishing.

[0031] To ensure the dispersion of xanthan gum, more preferably, the xanthan gum is a 1wt%-5wt% aqueous solution of xanthan gum.

[0032] Preferably, the alkali is KOH.

[0033] Preferably, the alumina particle size in the alumina slurry is 300-600 nm; for example, it can be 300 nm, 400 nm, 500 nm, or 600 nm.

[0034] Preferably, the complexing agent is any one or more selected from hydroxyethylidene diphosphonic acid, EDTA, and citric acid.

[0035] More preferably, the complexing agent is hydroxyethylidene diphosphonic acid.

[0036] Preferably, the bactericide is selected from Kathon, 1,2-benzisothiazolin-3-one, and 1,3-dichloro-5,5-dimethylhydantoin.

[0037] More preferably, the bactericide is 1,2-benzisothiazolin-3-one.

[0038] A second aspect of the present invention provides an ITO glass polishing slurry, which is obtained by diluting the above-mentioned polishing slurry concentrate by 4-6 times.

[0039] Preferably, the content of impurity metal ions in the polishing solution is <5 ppm.

[0040] The heterometal ion content mentioned in this invention refers to the content of all metal ions other than K and Al.

[0041] Preferably, the polishing slurry obtained by diluting the above-mentioned concentrated polishing slurry 5 times, under the conditions of polishing pressure of 6 psi, polishing speed of upper / lower plate of 90 / 70 rpm, polishing slurry flow rate of 200 mL / min, polishing time of 1 min, and polishing temperature of 25℃, has a polishing rate of ≥40 nm / min on ITO glass.

[0042] More preferably, the polishing slurry obtained by diluting the above-mentioned polishing slurry concentrate by 5 times, under the conditions of polishing pressure of 6 psi, polishing speed of upper / lower plate of 90 / 70 rpm, polishing slurry flow rate of 200 mL / min, polishing time of 1 min, and polishing temperature of 25°C, has a polishing rate of 40-45 nm / min on ITO glass.

[0043] Preferably, the polishing slurry obtained by diluting the above-mentioned concentrated polishing slurry by 5 times, under the conditions of polishing pressure of 6 psi, polishing speed of upper / lower plate of 90 / 70 rpm, polishing slurry flow rate of 200 mL / min, polishing time of 1 min, and polishing temperature of 25℃, after polishing ITO glass, the surface roughness Ra of ITO glass is ≤0.6nm.

[0044] More preferably, the polishing slurry obtained by diluting the above-mentioned polishing slurry concentrate by 5 times, under the conditions of polishing pressure of 6 psi, polishing speed of upper / lower plate of 90 / 70 rpm, polishing slurry flow rate of 200 mL / min, polishing time of 1 min, and polishing temperature of 25°C, after polishing ITO glass, the surface roughness Ra of ITO glass is 0.4-0.6 nm.

[0045] The third aspect of the present invention provides a method for preparing the above-mentioned polishing slurry concentrate, the method comprising: dispersing alumina slurry in water, and sequentially adding inorganic salt, complexing agent and bactericide under stirring conditions to obtain the polishing slurry concentrate.

[0046] Preferably, the preparation method of the polishing slurry concentrate includes the following steps:

[0047] S1. Add water and alumina slurry into the reactor and stir at a speed of 100-200 r / min;

[0048] S2. Add inorganic salt and stir for 8-15 minutes at a speed of 100-200 r / min.

[0049] S3. Add the complexing agent and stir for 8-15 minutes at a speed of 100-200 r / min.

[0050] S4. Add bactericide and stir for 25-35 minutes at a speed of 100-200 r / min.

[0051] S5. Filling.

[0052] Preferably, the method for preparing the alumina slurry includes: dispersing alumina in water, adding alkali and suspending agent sequentially under stirring conditions to obtain a mixture, homogenizing the mixture to obtain the alumina slurry.

[0053] More preferably, the method for preparing the alumina slurry includes the following steps:

[0054] S1. Add water to the reactor and stir at a speed of 30-60 r / min;

[0055] S2. Add alumina and stir for 25-35 minutes at a speed of 100-200 r / min.

[0056] S3. Add alkali and stir for 8-15 minutes at a speed of 100-200 r / min;

[0057] S4. Add the suspending agent and stir at 100-200 r / min for 25-35 min to obtain the mixture;

[0058] S5. Homogenize the mixture to obtain alumina slurry.

[0059] Preferably, the homogenization pressure is 10,000-20,000 psi; for example, it can be 10,000 psi, 12,000 psi, 14,000 psi, 15,000 psi, 16,000 psi, 18,000 psi, or 20,000 psi.

[0060] Preferably, the homogenization temperature is 10-15℃; for example, it can be 10℃, 11℃, 12℃, 13℃, 14℃, or 15℃.

[0061] If the homogenization temperature is too low (e.g., 8℃), the slurry viscosity will be too high, the fluidity will be poor, and it will be difficult to effectively disperse the abrasive. If the homogenization temperature is too high (e.g., 25℃), the abrasive will easily collide and thermally agglomerate, which is not conducive to dispersion.

[0062] Preferably, the number of cycles during homogenization is 1 or 2.

[0063] The fourth aspect of the present invention provides an application of the above-mentioned polishing slurry concentrate, after dilution, as an ITO glass polishing slurry.

[0064] Preferably, polished ITO glass is used as automotive glass.

[0065] More preferably, the polished ITO glass is automotive roof glass and / or window glass.

[0066] Preferably, the haze of the ITO glass after polishing is ≤0.5%.

[0067] More preferably, the haze of the ITO glass after polishing is 0.2%-0.5%.

[0068] Preferably, the surface roughness Ra of the ITO glass after polishing is ≤0.6nm.

[0069] Preferably, the surface roughness Ra of the ITO glass after polishing is 0.4-0.6 nm.

[0070] As described above, the ITO glass polishing slurry concentrate and its preparation method of the present invention have the following beneficial effects:

[0071] The polishing slurry concentrate of this invention, when diluted 5 times for polishing ITO glass, can achieve a polishing rate of 40-45 nm / min. At the same time, the surface of the ITO glass is free of scratches after polishing, and the surface roughness can be reduced to within 0.6 nm, achieving a balance between polishing rate and surface quality. The haze can reach ≤0.5%, and the low haze ensures high visual clarity, meeting the standards for high-end automotive glass.

[0072] The polishing slurry of this invention, after dilution, has a metal ion content of <5ppm, which effectively avoids the contamination of the ITO film by metal ions during the polishing process, ensuring that the conductivity and optical transmittance of the ITO glass are not affected after polishing. In addition, compared with the direct use of finished polishing slurry, the concentrated form significantly reduces storage and transportation costs, and the amount used can be flexibly formulated according to actual needs, reducing material waste. Detailed Implementation

[0073] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0074] Unless otherwise specified, all process equipment or devices not specifically described in the embodiments are conventional equipment or devices in the art. Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the presence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps. It should also be understood that the combined connection relationship between one or more devices / devices mentioned in the present invention does not preclude the existence of other devices / devices before or after the combined devices / devices, or the insertion of other devices / devices between these explicitly mentioned devices / devices. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not intended to limit the order of the method steps or limit the scope of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.

[0075] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention; in the specification and claims of the present invention, unless otherwise expressly stated in the text, the singular forms "a", "an" and "this" include the plural forms.

[0076] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0077] The surface quality of ITO films used in automotive glass (such as roof windows and side windows) has extremely stringent requirements. As components that directly receive sunlight and external visibility, roof windows require extremely low haze (typically ≤1%) and high light transmittance. Any microscopic scratches or excessive roughness can lead to light scattering, glare, and visual distortion, directly affecting driving safety and passenger experience. Furthermore, roof windows are exposed to harsh environments such as high temperatures, extreme cold, and rain / snow erosion for extended periods, and surface defects can become corrosion initiation points, causing ITO film failure. In addition, roof windows often integrate antennas, defrosting, and heating functions, requiring the ITO film to have extremely low levels of metallic impurity ions to avoid signal attenuation and electrical performance degradation.

[0078] Based on the above requirements, this invention provides a concentrated ITO glass polishing slurry. This concentrated slurry, after dilution during polishing, achieves excellent surface quality with a surface roughness ≤0.6nm, zero scratches, and haze ≤0.5%, while maintaining a high polishing rate. The concentrated form avoids the high storage and transportation costs of traditional finished polishing slurries, which cannot simultaneously meet the requirements of efficiency, smoothness, and purity. Therefore, the concentrated polishing slurry of this invention can meet the requirements of automotive glass and has broad application prospects.

[0079] The alumina particles used in the following embodiments of the present invention have a particle size of 0.4-0.6 μm and a curved morphology.

[0080] The xanthan gum used in Examples 1-3 and Comparative Examples 4-6 of the present invention has a viscosity of 1500 cp.

[0081] Example 1

[0082] This embodiment 1 provides an ITO glass polishing slurry concentrate. Based on the total weight of the concentrate, the concentrate specifically includes the following components: 50wt% alumina slurry, 1.5wt% inorganic salt (KCl), 0.1wt% complexing agent (hydroxyethylidene diphosphonic acid), 0.005wt% bactericide (1,2-benzisothiazolin-3-one), and the balance being water.

[0083] Based on the total weight of the alumina slurry, the alumina slurry specifically includes: 40 wt% alumina, 53.5 wt% water, 1.5 wt% suspending agent (2% xanthan gum), and the balance being alkali (50% KOH).

[0084] The specific preparation method of the above-mentioned polishing slurry concentrate is as follows:

[0085] 1) Preparation of alumina slurry

[0086] S1. Add water to a clean reactor according to the ratio and start stirring at a speed of 50±2 r / min;

[0087] S2. Add alumina according to the ratio and continue stirring until it is dissolved evenly. Stirring time is 30±2 min and speed is 160±5 r / min.

[0088] S3. Keep the rotation speed constant and continue to add KOH, stirring for 10±1 min;

[0089] S4. Keep the rotation speed constant and continue to add xanthan gum. Stir for 30±2 minutes to obtain the slurry.

[0090] S5. Pass the slurry through a homogenizer (homogenization pressure 15000±50psi, temperature 12-14℃, 1 cycle) to obtain an alumina slurry with a solid content of 40wt%.

[0091] 2) Preparation of polishing slurry concentrate

[0092] S1. Add alumina slurry to a clean reactor according to the specified ratio, start stirring, and set the stirring speed to 150±5 r / min;

[0093] S2. Add inorganic salts according to the ratio, stir for 10±1 min, and rotate at 150 r / min.

[0094] S3. Keep the rotation speed constant and continue to add complexing agent, stirring for 10±1 min;

[0095] S4. Keep the rotation speed constant and continue to add bactericide, stirring for 30±2 minutes;

[0096] S5. Filling.

[0097] Example 2

[0098] Example 2 provides an ITO glass polishing slurry concentrate, which differs from Example 1 in that the amount of alumina slurry added is replaced with 45wt%; the remaining components and preparation methods are the same as in Example 1.

[0099] Example 3

[0100] Example 3 provides a concentrated ITO glass polishing slurry, which differs from Example 1 in that: the alumina slurry has a solid alumina content of 35wt% and a xanthan gum content of 1wt%; the remaining components and preparation methods are the same as in Example 1.

[0101] Comparative Example 1

[0102] Comparative Example 1 provides an ITO glass polishing slurry concentrate, which differs from Example 1 in that 2% xanthan gum is replaced with 2% sodium carboxymethyl cellulose; the remaining components and preparation methods are the same as in Example 1.

[0103] Comparative Example 2

[0104] Comparative Example 2 provides an ITO glass polishing slurry concentrate, which differs from Example 1 in that the xanthan gum with a viscosity of 1500 cp is replaced with xanthan gum with a viscosity of 500 cp; the remaining components and preparation methods are the same as in Example 1.

[0105] Comparative Example 3

[0106] Comparative Example 3 provides an ITO glass polishing slurry concentrate, which differs from Example 1 in that the xanthan gum with a viscosity of 1500 cp is replaced with xanthan gum with a viscosity of 2500 cp; the remaining components and preparation methods are the same as in Example 1.

[0107] Comparative Example 4

[0108] Comparative Example 4 provides an ITO glass polishing solution concentrate, which differs from Example 1 in that the amount of alkali added is reduced so that the pH of the concentrate is 11.2; the remaining components and preparation methods are the same as in Example 1.

[0109] Comparative Example 5

[0110] Comparative Example 5 provides an ITO glass polishing slurry concentrate, which differs from Example 1 in that: no inorganic salts are added; the remaining components and preparation methods are the same as in Example 1.

[0111] Comparative Example 6

[0112] Comparative Example 6 provides an ITO glass polishing slurry concentrate, which differs from Example 1 in that: no complexing agent is added; the remaining components and preparation methods are the same as in Example 1.

[0113] The formulations of the concentrates in the above embodiments and comparative examples are shown in Tables 1 and 2.

[0114] Table 1 Alumina slurry formulation

[0115]

[0116] Table 2 Polishing slurry concentrate formulation

[0117]

[0118] Test section

[0119] The performance of the polishing slurry concentrates prepared in the above embodiments and comparative examples of this application was tested. The concentrates were diluted five times to prepare polishing slurries for subsequent performance testing. The specific testing methods are as follows:

[0120] 1) Polishing Rate Test: Process conditions were as follows: Polishing object: 8-inch ITO glass with an indium tin oxide (ITO) thickness of 430 nm; polishing pad: SUBA800 polishing pad; polishing disk diameter: 914 mm; polishing pressure: 6 psi; polishing disk rotation speed: 90 / 70 rpm; polishing fluid flow rate: 200 mL / min; polishing time: 1 min; polishing temperature: 25℃. The polishing rate was measured using a KLA non-metallic film thickness gauge (F50). Specifically, the thickness of the single-crystal silicon wafer was measured before and after polishing. The polishing rate was calculated by dividing the difference in film thickness before and after polishing by the polishing time. The test results are shown in Table 3.

[0121] 2) Surface roughness: The surface roughness was tested using an atomic force microscope. The test area at each location was 10μm*10μm. The average roughness of the three locations was calculated, and the results are shown in Table 3.

[0122] 3) Surface scratches: The polished ITO glass was observed using a laser microscope, and the scratches were counted (scratches with a length > 0.16 μm were included). The results are shown in Table 3.

[0123] 4) Haze test: The haze of the polished ITO glass was tested using a ColorSpectrum CS-720 haze meter.

[0124] 5) The content of metal ions in the solution was tested using inductively coupled plasma optical emission spectrometry (ICP-OES). Except for Comparative Example 6, the content of heterometallic ions (excluding K and Al ions) in all experimental examples was <5 ppm, while the content of heterometallic ions in Comparative Example 6 was 11 ppm.

[0125] Table 3. Performance test results of polishing slurry

[0126]

[0127] According to the performance test results in Table 3, when ITO glass is polished using the polishing solution obtained by diluting the concentrate in Examples 1-3 of this application, the polishing rate is ≥40nm / min, the surface roughness Ra of the ITO glass after polishing is ≤0.6, no scratches are produced on the glass, and the haze can reach the standard of <0.5%.

[0128] Compared to Example 1, in Comparative Example 1, the suspending agent was replaced with an equal amount of sodium carboxymethyl cellulose. The resulting concentrated solution was diluted and used to polish ITO glass, leading to a significant increase in the surface roughness Ra of the polished ITO glass and the formation of two scratches on the glass surface, failing to meet the standards for automotive glass. This is because sodium carboxymethyl cellulose cannot effectively suspend and stabilize the alumina particles in the polishing solution, resulting in particle deposition or agglomeration. This reduces the number of effectively cutting particles, lowers the polishing rate, and the agglomerated abrasive damages the glass surface, leading to increased surface roughness. In Comparative Example 2, the suspending agent was replaced with an equal amount of low-viscosity xanthan gum, which had insufficient suspending capacity for alumina abrasives. This resulted in insufficient and unevenly distributed abrasives delivered to the polishing interface, directly reducing the material removal rate and damaging the ITO glass surface. Increased surface roughness and scratches occurred. In Comparative Example 3, the suspending agent was replaced with an equal amount of high-viscosity xanthan gum. The high-viscosity suspending agent hindered the flow and mass transfer of the polishing slurry, slowing down the polishing rate. The high-viscosity suspending agent coated the abrasive surface, forming a thick and hard film that easily damaged the ITO glass surface during polishing. In Comparative Example 4, the pH of the concentrate was lowered to 11.2. The decrease in pH slowed down the etching rate of the polishing slurry, and polishing mainly relied on the mechanical grinding of the abrasive, resulting in increased surface roughness of the ITO glass after polishing and scratches on the glass surface. In Comparative Example 5, no inorganic salts were added, resulting in a reduced polishing rate and increased surface roughness and haze of the ITO glass after polishing. In Comparative Example 6, no complexing agent was added, and the content of impurity metal ions in the polishing slurry increased, leading to a significant increase in haze of the ITO glass after polishing.

[0129] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A concentrated ITO glass polishing slurry, characterized in that, The polishing slurry concentrate comprises the following components by weight: 30wt%-60wt% alumina slurry, 0.1wt%-5wt% inorganic salt, 0.001wt%-1wt% complexing agent, 0.001wt%-0.1wt% bactericide, and the balance being water; the alumina slurry has a solid content of 20wt%-50wt%, and the alumina slurry also includes a suspending agent and an alkali, wherein the alkali is used to adjust the pH of the polishing slurry concentrate to ≥11.

5.

2. The polishing slurry concentrate according to claim 1, characterized in that, The suspending agent is xanthan gum; And / or, the base is KOH; And / or, the alumina particle size in the alumina slurry is 300-600 nm.

3. The polishing slurry concentrate according to claim 2, characterized in that, The xanthan gum has a viscosity of 1000-2000 cP at 25°C; And / or, based on the total weight of the alumina slurry, the amount of xanthan gum added is 0.001wt%-0.1wt%.

4. The polishing slurry concentrate according to claim 1, characterized in that, The inorganic salt is potassium chloride; And / or, the complexing agent is any one or more selected from hydroxyethylidene diphosphonic acid, EDTA, and citric acid; And / or, the bactericide is selected from Kathon, 1,2-benzisothiazolin-3-one, and 1,3-dichloro-5,5-dimethylhydantoin.

5. An ITO glass polishing slurry, characterized in that, The polishing slurry is obtained by diluting the concentrated polishing slurry of any one of claims 1-4 by 4-6 times. Preferably, the content of impurity metal ions in the polishing slurry is <5ppm.

6. A method for preparing a polishing slurry concentrate as described in any one of claims 1-4, characterized in that, The preparation method includes: dispersing alumina slurry in water, and sequentially adding inorganic salt, complexing agent and bactericide under stirring conditions to obtain the polishing liquid concentrate.

7. The preparation method according to claim 6, characterized in that, The method for preparing the alumina slurry includes: dispersing alumina in water, adding alkali and suspending agent sequentially under stirring conditions to obtain a mixture, homogenizing the mixture to obtain the alumina slurry.

8. The preparation method according to claim 7, characterized in that, The homogenization pressure is 10,000-20,000 psi; And / or, the homogenization temperature is 10-15°C; And / or, the number of cycles during homogenization is 1 or 2; And / or, the stirring speed is 100-200 r / min.

9. The use of the polishing slurry concentrate as described in any one of claims 1-4, after dilution, as an ITO glass polishing slurry.

10. The application according to claim 9, characterized in that, Polished ITO glass is used as automotive glass; And / or, the haze of the ITO glass after polishing is ≤0.5%; and / or, the surface roughness Ra of the ITO glass after polishing is ≤0.6nm.

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