Aluminum alloy chemical mechanical polishing solution as well as preparation method and application thereof

Abstract

The invention relates to an aluminum alloy chemical mechanical polishing solution and a preparation method and application thereof.The polishing solution is prepared from, by mass, 20%-30% of grinding materials, 1%-5% of oxidizing agents, 0.01%-1% of complexing agents, 0.01%-1% of pH regulators and the balance deionized water; wherein the complexing agent is a mixture of a first complexing agent and a second complexing agent, the first complexing agent is short-carbon-chain organic acid with the carbon atom number of 2-4, and the second complexing agent is long-carbon-chain organic acid with the carbon atom number of 8-10; the grinding material is a mixture of aluminum oxide and silicon dioxide, and the silicon dioxide is a mixture with the particle size of 10-40 nm, 40-70 nm and 90-110 nm. Compared with the prior art, the method has the advantages that the removal rate can be increased, and the surface roughness of the workpiece is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of metal surface treatment, and in particular to an aluminum alloy chemical mechanical polishing liquid and a preparation method and application thereof. Background Art

[0002] Aluminum alloy materials are widely used in metal reflectors, 3C digital product manufacturing, micro-nano manufacturing, optical sensors and large-scale integrated circuits due to their low density, good thermal and electrical conductivity, corrosion resistance and optical reflectivity. In addition, aluminum alloy materials are easy to recycle and protect the environment, meeting the requirements of green design. In recent years, with the development of high-tech, higher requirements have been put forward for material planar processing technology with extremely high precision and almost no defects. In some planar devices, some key or important components require some alloy materials to achieve ultra-precision planar processing with extremely high precision and almost no defects. In addition, due to the low hardness of aluminum and its aluminum products (density is only 2.g / cm 3 During the processing and forming process, the surface is easily damaged by mechanical means, resulting in surface defects such as wear and scratches, which puts higher requirements on the performance of aluminum alloy polishing liquid in all aspects.

[0003] Chemical Mechanical Polishing (CMP) of aluminum alloy is an ultra-precision machining technology that combines chemical and mechanical effects. This technology is mainly used to improve the flatness and finish of aluminum alloy surfaces and achieve global flattening to meet the modern industry's requirements for extremely high precision and nearly defect-free material surfaces. CMP technology was first used in the semiconductor industry, especially in 64-bit RAM manufacturing, and later expanded to the entire semiconductor industry and gradually found application in other fields.

[0004] CMP technology involves the workpiece material being subjected to both chemical and mechanical effects in the polishing system to achieve the removal of surface material to achieve the desired brightness and flattening effect. Unlike mechanical polishing, the polishing liquid used in CMP contains a variety of chemical components, which not only oxidizes the workpiece surface, but also includes the full contact between the abrasive medium and the rough parts of the material surface during mechanical polishing to reduce the surface roughness of the material.

[0005] Currently, aluminum alloy polishing liquids on the market are mainly divided into two types: acid polishing liquid and alkaline polishing liquid. The earliest and most mature acid polishing liquid is the traditional three-acid chemical polishing liquid, which is composed of concentrated sulfuric acid, concentrated phosphoric acid and concentrated nitric acid in different proportions. However, during the polishing process, nitric acid will produce a large amount of yellow nitrogen oxides NO xGas (commonly known as "yellow smoke") pollutes the environment. Even if subsequent studies have shown that nitric acid can be omitted, for example, publication number CN106757039A provides an aluminum alloy polishing liquid that does not contain nitric acid, but in terms of overall degree, the surface of the aluminum alloy after polishing is rough and the glossiness is insufficient. Compared with acidic polishing liquid, alkaline polishing liquid is environmentally friendly. For example, CN102925900A discloses an alkaline chemical polishing liquid composed of sodium hydroxide, sodium nitrate, sodium fluoride, sodium phosphate and water, but the polishing effect is poor and the surface quality is poor.

[0006] The alkaline polishing liquid for aluminum alloys currently on the market still has the problems of low polishing rate during use, which may cause scratches on the surface of aluminum alloys, high surface roughness, low yield rate, etc. Therefore, a chemical mechanical polishing liquid is needed that can achieve trace removal of workpiece materials, obtain ultra-smooth, less / no damage processing surface, and is green and environmentally friendly. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide an aluminum alloy chemical mechanical polishing liquid and its preparation method and application, which can improve the removal rate and reduce the surface roughness of the workpiece.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] One of the technical solutions of the present invention is to provide an aluminum alloy chemical mechanical polishing liquid. The raw materials for preparing the polishing liquid include the following components in terms of mass percentage: 20% to 30% abrasive, 1% to 5% oxidant, 0.01% to 1% complexing agent, 0.01% to 1% pH regulator, and the rest is deionized water;

[0010] Wherein, the complexing agent is a mixture of a first complexing agent and a second complexing agent, the first complexing agent is a short-chain organic acid with 2 to 4 carbon atoms, and the second complexing agent is a long-chain organic acid with 8 to 10 carbon atoms;

[0011] The abrasive is a mixture of aluminum oxide and silicon dioxide, and the silicon dioxide is a mixture with particle sizes of 10-40nm, 40-70nm and 90-110nm.

[0012] Furthermore, the silicon dioxide is a mixture of particles with diameters of 25 to 35 mm, 55 to 65 mm and 95 to 105 mm, and exists in the form of a solution, wherein the mass content of silicon dioxide is 10% to 40%.

[0013] Furthermore, the first complexing agent includes one or more of succinic acid, oxalic acid, glycine, citric acid, and ammonium malate; preferably oxalic acid and glycine; more preferably a mixture of oxalic acid and glycine, with a mass ratio of 1:(0.5-2).

[0014] Furthermore, the second complexing agent includes one or more of suberic acid, alpha-carboxyisooctanoic acid, and (2-carboxy-4-isopropyl-3-pyrrolidineacetic acid; preferably alpha-carboxyisooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid; more preferably a mixture of alpha-carboxyisooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid, with a mass ratio of 1:(0.5~2).

[0015] Furthermore, the mass ratio of the first complexing agent to the second complexing agent is 1:(1-10), preferably 1:(4-8).

[0016] Furthermore, the mass ratio of silicon dioxide having particle sizes of 10 to 40 nm, 40 to 70 nm, and 90 to 110 nm is 1:(0.2 to 0.5):(0.02 to 0.05).

[0017] Furthermore, the particle size of the aluminum oxide is 30nm to 40nm.

[0018] Furthermore, the mass ratio of aluminum oxide to silicon dioxide is 1:(1-5).

[0019] Furthermore, the oxidant includes one or more of hydrogen peroxide, phosphoric acid, sulfuric acid, nitric acid, acetic acid, and ammonium bifluoride; preferably hydrogen peroxide.

[0020] Furthermore, the pH of the polishing liquid is 9-10, and the pH adjuster used includes an inorganic acid and an inorganic base, the inorganic acid includes hydrochloric acid, phosphoric acid or nitric acid, and the inorganic base includes potassium hydroxide or sodium hydroxide.

[0021] The second technical solution of the present invention is to provide a method for preparing an aluminum alloy chemical mechanical polishing liquid, comprising the following steps:

[0022] The abrasive, the complexing agent, the pH regulator and the oxidant are uniformly mixed to obtain the polishing liquid.

[0023] Furthermore, the abrasive is mixed with the complexing agent, the pH regulator is added, the oxidant is added, and the mixture is mixed evenly to obtain the polishing liquid.

[0024] The third technical solution of the present invention is to provide an application of an aluminum alloy chemical mechanical polishing liquid, and use the polishing liquid to polish the aluminum alloy.

[0025] Furthermore, before polishing the aluminum alloy, the aluminum alloy is ground with sandpaper and the surface is cleaned.

[0026] Furthermore, the polishing pad is adhered to the polishing plate to apply pressure, and the aluminum alloy is polished using the polishing liquid.

[0027] Furthermore, the polishing pad has a thickness of 1.3 to 1.5 mm, a hardness of 50 to 65A, a compression rate of 10% to 15%, and a pore size of 40 to 55 μm.

[0028] Furthermore, the polishing conditions include: a polishing pressure of 8 to 19 kg, a polishing disc rotation speed of 10 to 85 rpm, a polishing disc temperature of 25 to 40° C., and a polishing liquid feed speed of 1 to 5 mL / min.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] (1) The present invention selects a first complexing agent with a short carbon chain and a second complexing agent with a long carbon chain to achieve a relatively good complexing effect. The short carbon chain complexing agent has a compact structure and can quickly combine with the target metal ions, while the long carbon chain complexing agent can disperse the metal ions more effectively due to its chain length advantage, making up for the limitations of the short carbon chain complexing agent and enhancing the stability of the overall system. In addition, the silicon dioxide and aluminum oxide are compounded in the abrasive and then react with the complexing agent, which can alleviate the disadvantage that the short carbon chain cannot disperse the aluminum ions in the polishing process, and at the same time, a relatively good polishing effect can be obtained, and the stability of the product can be relatively high.

[0031] (2) The present invention selects the abrasive as a mixture of aluminum oxide and silicon dioxide, wherein the silicon dioxide is a mixture of particles with diameters of 10 to 40 nm, 40 to 70 nm, and 90 to 110 nm, so that the aluminum alloy has good mechanical force during the polishing process and can achieve good polishing removal efficiency on the aluminum alloy surface.

[0032] (3) The present invention adds 1%-5% oxidant to accelerate the oxidation rate of the aluminum alloy surface and form an oxide film, which can protect the surface and improve the smoothness and flatness of the aluminum alloy surface.

[0033] (4) The present invention adds 0.01%-1% of a complexing agent to the system. A complexing agent with strong complexing ability can serve as a catalyst for the oxidation of the aluminum substrate, so that more metal cations are generated in the fluid, which is beneficial to the dissolution of the Al matrix. A complexing agent with large steric hindrance and high electrostatic repulsion (high charge density) can form a stable boundary layer on the substrate surface and is beneficial to the nanoparticles formed during the dispersion process, thereby improving the polishing removal efficiency of the aluminum alloy and improving the surface quality.

[0034] (5) The preparation method of the present invention is simple, does not generate pollutants, and is easy to produce on a large scale. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments. Based on the given embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0036] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art.

[0037] In the following examples, the CAS number of alpha-carboxyisooctanoic acid is 3974-36-5, which was purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; the CAS number of 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid is 52497-36-6, which was purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0038] Example 1

[0039] A chemical mechanical polishing liquid for aluminum alloy, wherein the raw materials for preparing the polishing liquid include the following components in terms of mass percentage: 20% abrasive, 1% hydrogen peroxide (oxidant), 0.05% complexing agent, nitric acid and potassium hydroxide as pH regulators to make the pH of the polishing liquid 10, and the rest being deionized water.

[0040] The abrasive is aluminum oxide and silicon dioxide; the particle size of the silicon dioxide is a mixture of 30nm, 60nm and 100nm, and the mass ratio is 1:0.33:0.033; the particle size of aluminum oxide is 30nm; the mass ratio of aluminum oxide to silicon dioxide is 1:3. The mass content of silicon dioxide is 20%.

[0041] The complexing agent includes a first complexing agent and a second complexing agent, wherein the first complexing agent is oxalic acid and glycine, and the second complexing agent is alpha-carboxy isooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid. The mass ratio of oxalic acid, glycine, alpha-carboxy isooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid is 1:1:6:6.

[0042] The concentration of the nitric acid is 40wt%, and the concentration of the potassium hydroxide is 1mol / L.

[0043] The specific preparation steps of the polishing liquid are as follows:

[0044] 0.05% of complexing agent is added to the abrasive and stirred evenly; pH ​​regulator is added to the obtained mixture to make the pH value 10 and stirred evenly; oxidant is added and stirred evenly, and the obtained mixed solution is the aluminum alloy chemical mechanical polishing liquid.

[0045] The preparation process of the aluminum alloy polishing is:

[0046] The aluminum alloy was polished with 2000-grit sandpaper for 1 minute, and the surface was cleaned with deionized water; the aluminum alloy was placed in a polishing liquid, a polishing pad was attached to a polishing disk for pressure application, the aluminum alloy was polished with the polishing liquid, washed with water, and then cleaned with anhydrous ethanol and dried to obtain a polished aluminum alloy workpiece.

[0047] The polishing pad has a thickness of 1.4 mm, a hardness of 60A, a compression rate of 15%, and a pore size of 50 μm. The polishing conditions include: a polishing pressure of 12 kg, a polishing disc rotation speed of 50 rpm, a polishing disc temperature of 35° C., and a polishing liquid feed speed of 2.5 mL / min.

[0048] Example 2

[0049] Compared with Example 1, most of them are the same except for the selection of the complexing agent.

[0050] A chemical mechanical polishing liquid for aluminum alloy, wherein the raw materials for preparing the polishing liquid include the following components in terms of mass percentage: 20% abrasive, 1% hydrogen peroxide (oxidant), 0.05% complexing agent, nitric acid and potassium hydroxide as pH regulators to make the pH of the polishing liquid 10, and the rest being deionized water.

[0051] The abrasive is aluminum oxide and silicon dioxide; the particle size of the silicon dioxide is a mixture of 30nm, 60nm and 100nm, and the mass ratio is 1:0.33:0.033; the particle size of aluminum oxide is 30nm; the mass ratio of aluminum oxide to silicon dioxide is 1:3. The mass content of silicon dioxide is 20%.

[0052] The complexing agent includes a first complexing agent and a second complexing agent, the first complexing agent is oxalic acid, the second complexing agent is 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid, and the mass ratio of the oxalic acid to the 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid is 1:6.

[0053] The concentration of the nitric acid is 40wt%, and the concentration of the potassium hydroxide is 1mol / L.

[0054] The specific preparation steps of the polishing liquid are as follows:

[0055] 0.05% of complexing agent is added to the abrasive and stirred evenly; pH ​​regulator is added to the obtained mixture to make the pH value 10 and stirred evenly; oxidant is added and stirred evenly, and the obtained mixed solution is the aluminum alloy chemical mechanical polishing liquid.

[0056] The preparation process of the aluminum alloy polishing is:

[0057] The aluminum alloy was polished using a SG0031 portable polisher. The aluminum alloy was polished using 2000-grit sandpaper for 1 minute, and the surface was cleaned using deionized water; the aluminum alloy was placed in a polishing liquid, the polishing pad was attached to the polishing disk for pressure, and the aluminum alloy was polished using the polishing liquid, washed with water, and then cleaned with anhydrous ethanol and dried to obtain a polished aluminum alloy workpiece.

[0058] The polishing pad has a thickness of 1.4 mm, a hardness of 60A, a compression rate of 15%, and a pore size of 50 μm. The polishing conditions include: a polishing pressure of 12 kg, a polishing disc rotation speed of 50 rpm, a polishing disc temperature of 35° C., and a polishing liquid feed speed of 2.5 mL / min.

[0059] Example 3

[0060] Compared with Example 1, most of them are the same, except that the mass ratios of oxalic acid, glycine, alpha-carboxyisooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid are different.

[0061] A chemical mechanical polishing liquid for aluminum alloy, wherein the raw materials for preparing the polishing liquid include the following components in terms of mass percentage: 20% abrasive, 1% hydrogen peroxide (oxidant), 0.05% complexing agent, nitric acid and potassium hydroxide as pH regulators to make the pH of the polishing liquid 10, and the rest being deionized water.

[0062] The abrasive is aluminum oxide and silicon dioxide; the particle size of the silicon dioxide is a mixture of 30nm, 60nm and 100nm, and the mass ratio is 1:0.33:0.033; the particle size of aluminum oxide is 30nm; the mass ratio of aluminum oxide to silicon dioxide is 1:3. The mass content of silicon dioxide is 20%.

[0063] The complexing agent includes a first complexing agent and a second complexing agent, wherein the first complexing agent is oxalic acid and glycine, and the second complexing agent is alpha-carboxy isooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid. The mass ratio of oxalic acid, glycine, alpha-carboxy isooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid is 1:1:1:1.

[0064] The concentration of the nitric acid is 40wt%, and the concentration of the potassium hydroxide is 1mol / L.

[0065] The specific preparation steps of the polishing liquid are as follows:

[0066] 0.05% of complexing agent is added to the abrasive and stirred evenly; pH ​​regulator is added to the obtained mixture to make the pH value 10 and stirred evenly; oxidant is added and stirred evenly, and the obtained mixed solution is the aluminum alloy chemical mechanical polishing liquid.

[0067] The preparation process of the aluminum alloy polishing is:

[0068] The aluminum alloy was polished using a SG0031 portable polisher. The aluminum alloy was polished using 2000-grit sandpaper for 1 minute, and the surface was cleaned using deionized water; the aluminum alloy was placed in a polishing liquid, the polishing pad was attached to the polishing disk for pressure, and the aluminum alloy was polished using the polishing liquid, washed with water, and then cleaned with anhydrous ethanol and dried to obtain a polished aluminum alloy workpiece.

[0069] The polishing pad has a thickness of 1.4 mm, a hardness of 60A, a compression rate of 15%, and a pore size of 50 μm. The polishing conditions include: a polishing pressure of 12 kg, a polishing disc rotation speed of 50 rpm, a polishing disc temperature of 35° C., and a polishing liquid feed speed of 2.5 mL / min.

[0070] Example 4

[0071] Compared with Example 1, most of them are the same, except that the raw materials for preparing the polishing liquid include the following components: 30% abrasive, 5% hydrogen peroxide (oxidant), 1% complexing agent, pH adjusters are nitric acid and potassium hydroxide, so that the pH of the polishing liquid is 10, and the rest is deionized water.

[0072] Example 5

[0073] Compared with Example 1, most of them are the same, except that the raw materials for preparing the polishing liquid include the following components: 25% abrasive, 3% hydrogen peroxide (oxidant), 0.1% complexing agent, pH adjusters are nitric acid and potassium hydroxide, so that the pH of the polishing liquid is 10, and the rest is deionized water.

[0074] Example 6

[0075] Compared with Example 1, most of them are the same, except that the mass ratio of oxalic acid, glycine, alpha-carboxy isooctanoic acid, and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid is different, and the mass ratio of oxalic acid, glycine, alpha-carboxy isooctanoic acid, and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid is 1:1:10:10.

[0076] Example 7

[0077] Compared with Example 1, most of the contents are the same, except that the mass ratio of the silica particles of 30 nm, 60 nm and 100 nm is adjusted to 1:0.2:0.02.

[0078] Example 8

[0079] Compared with Example 1, most of the contents are the same, except that the mass ratio of the silica particles of 30 nm, 60 nm and 100 nm is adjusted to 1:0.5:0.05.

[0080] Comparative Example 1

[0081] Compared with Example 1, most of them are the same except that the selection of silicon dioxide is different.

[0082] A chemical mechanical polishing liquid for aluminum alloy, wherein the raw materials for preparing the polishing liquid include the following components in terms of mass percentage: 20% abrasive, 1% hydrogen peroxide (oxidant), 0.05% complexing agent, nitric acid and potassium hydroxide as pH regulators to make the pH of the polishing liquid 10, and the rest being deionized water.

[0083] The abrasive is aluminum oxide and silicon dioxide; the particle size of the silicon dioxide is 30 nm; the mass ratio of aluminum oxide to silicon dioxide is 1:3, and the mass content of silicon dioxide is 20%.

[0084] The complexing agent includes a first complexing agent and a second complexing agent, wherein the first complexing agent is oxalic acid and glycine, and the second complexing agent is alpha-carboxy isooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid. The mass ratio of oxalic acid, glycine, alpha-carboxy isooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid is 1:1:6:6.

[0085] The concentration of the nitric acid is 40wt%, and the concentration of the potassium hydroxide is 1mol / L.

[0086] The specific preparation steps of the polishing liquid are as follows:

[0087] 0.05% of complexing agent is added to the abrasive and stirred evenly; pH ​​regulator is added to the obtained mixture to make the pH value 10 and stirred evenly; oxidant is added and stirred evenly, and the obtained mixed solution is the aluminum alloy chemical mechanical polishing liquid.

[0088] The preparation process of the aluminum alloy polishing is:

[0089] The aluminum alloy was polished using a SG0031 portable polisher. The aluminum alloy was polished using 2000-grit sandpaper for 1 minute, and the surface was cleaned using deionized water; the aluminum alloy was placed in a polishing liquid, the polishing pad was attached to the polishing disk for pressure, and the aluminum alloy was polished using the polishing liquid, washed with water, and then cleaned with anhydrous ethanol and dried to obtain a polished aluminum alloy workpiece.

[0090] The polishing pad has a thickness of 1.4 mm, a hardness of 60A, a compression rate of 15%, and a pore size of 50 μm. The polishing conditions include: a polishing pressure of 12 kg, a polishing disc rotation speed of 50 rpm, a polishing disc temperature of 35° C., and a polishing liquid feed speed of 2.5 mL / min.

[0091] Comparative Example 2

[0092] Compared to Example 1, most of the details are the same, except that the abrasive is silica and does not contain alumina.

[0093] A chemical mechanical polishing liquid for aluminum alloy, wherein the raw materials for preparing the polishing liquid include the following components in terms of mass percentage: 20% abrasive, 1% hydrogen peroxide (oxidant), 0.05% complexing agent, nitric acid and potassium hydroxide as pH regulators to make the pH of the polishing liquid 10, and the rest being deionized water.

[0094] The abrasive is silicon dioxide; the particle size of the silicon dioxide is a mixture of 30 nm, 60 nm and 100 nm, and the mass ratio is 3:1:0.1; and the mass content of the silicon dioxide is 20%.

[0095] The complexing agent includes a first complexing agent and a second complexing agent, wherein the first complexing agent is oxalic acid and glycine, and the second complexing agent is alpha-carboxy isooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid. The mass ratio of oxalic acid, glycine, alpha-carboxy isooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid is 1:1:6:6.

[0096] The concentration of the nitric acid is 40wt%, and the concentration of the potassium hydroxide is 1mol / L.

[0097] The specific preparation steps of the polishing liquid are as follows:

[0098] 0.05% of complexing agent is added to the abrasive and stirred evenly; pH ​​regulator is added to the obtained mixture to make the pH value 10 and stirred evenly; oxidant is added and stirred evenly, and the obtained mixed solution is the aluminum alloy chemical mechanical polishing liquid.

[0099] The preparation process of the aluminum alloy polishing is:

[0100] The aluminum alloy was polished using a SG0031 portable polisher. The aluminum alloy was polished using 2000-grit sandpaper for 1 minute, and the surface was cleaned using deionized water; the aluminum alloy was placed in a polishing liquid, the polishing pad was attached to the polishing disk for pressure, and the aluminum alloy was polished using the polishing liquid, washed with water, and then cleaned with anhydrous ethanol and dried to obtain a polished aluminum alloy workpiece.

[0101] The polishing pad has a thickness of 1.4 mm, a hardness of 60A, a compression rate of 15%, and a pore size of 50 μm. The polishing conditions include: a polishing pressure of 12 kg, a polishing disc rotation speed of 50 rpm, a polishing disc temperature of 35° C., and a polishing liquid feed speed of 2.5 mL / min.

[0102] Comparative Example 3

[0103] Compared with Example 1, most of them are the same, except that the complexing agent is the second complexing agent, and the first complexing agent is not included.

[0104] A chemical mechanical polishing liquid for aluminum alloy, wherein the raw materials for preparing the polishing liquid include the following components in terms of mass percentage: 20% abrasive, 1% hydrogen peroxide (oxidant), 0.05% complexing agent, nitric acid and potassium hydroxide as pH regulators to make the pH of the polishing liquid 10, and the rest being deionized water.

[0105] The abrasive is aluminum oxide and silicon dioxide; the particle size of the silicon dioxide is a mixture of 30nm, 60nm and 100nm, and the mass ratio is 3:1:0.1; the particle size of aluminum oxide is 30nm; the mass ratio of aluminum oxide to silicon dioxide is 1:3. The mass content of silicon dioxide is 20%.

[0106] The complexing agent is and the second complexing agent, the second complexing agent is alpha-carboxy isooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidine acetic acid. The mass ratio of the alpha-carboxy isooctanoic acid and 2-carboxy-4-isopropyl-3-pyrrolidine acetic acid is 1:1.

[0107] The concentration of the nitric acid is 40wt%, and the concentration of the potassium hydroxide is 1mol / L.

[0108] The specific preparation steps of the polishing liquid are as follows:

[0109] 0.05% of complexing agent is added to the abrasive and stirred evenly; pH ​​regulator is added to the obtained mixture to make the pH value 10 and stirred evenly; oxidant is added and stirred evenly, and the obtained mixed solution is the aluminum alloy chemical mechanical polishing liquid.

[0110] The preparation process of the aluminum alloy polishing is:

[0111] The aluminum alloy was polished using a SG0031 portable polisher. The aluminum alloy was polished using 2000-grit sandpaper for 1 minute, and the surface was cleaned using deionized water; the aluminum alloy was placed in a polishing liquid, the polishing pad was attached to the polishing disk for pressure, and the aluminum alloy was polished using the polishing liquid, washed with water, and then cleaned with anhydrous ethanol and dried to obtain a polished aluminum alloy workpiece.

[0112] The polishing pad has a thickness of 1.4 mm, a hardness of 60A, a compression rate of 15%, and a pore size of 50 μm. The polishing conditions include: a polishing pressure of 12 kg, a polishing disc rotation speed of 50 rpm, a polishing disc temperature of 35° C., and a polishing liquid feed speed of 2.5 mL / min.

[0113] The polishing rate MRR and surface roughness Ra of the aluminum alloy after polishing of Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1.

[0114] Table 1 Polishing rate MRR and surface roughness Ra results of aluminum alloy after polishing

[0115] Polishing rate MRR / (nm / min) Surface roughness Ra / nm Example 1 350 0.12 Example 2 330 0.30 Example 3 337 0.20 Comparative Example 1 332 0.24 Comparative Example 2 281 0.55 Comparative Example 3 266 0.60

[0116] The polishing liquids prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were placed at room temperature for 150 days, and their properties are shown in Table 2.

[0117] Table 2 Polishing liquid performance test results

[0118] Characteristics Example 1 Stablize Example 2 Stablize Example 3 Stablize Comparative Example 1 Small amount of precipitation Comparative Example 2 Stablize Comparative Example 3 Small amount of precipitation

[0119] It can be seen from Table 1 and Table 2 that the polishing rate MRR and surface roughness Ra of the aluminum alloy after polishing in Examples 1 to 3 are relatively high, and the polishing liquid is relatively stable.

[0120] In Comparative Example 1, the abrasives are aluminum oxide and silicon dioxide; the silicon dioxide with a particle size of 30 nm has a high polishing rate MRR and surface roughness Ra of the aluminum alloy after polishing, but the polishing liquid is precipitated by a small part after standing for 150 days, and its stability is poor. The silicon dioxide particles with a smaller particle size have a larger specific surface area, which may lead to an increase in the van der Waals attraction between the particles, thereby reducing stability. In addition, small-particle silicon dioxide is more likely to condense at a lower concentration, because the repulsive potential energy between particles is proportional to the particle diameter, and the repulsion between small particles is weaker, and it is easier to aggregate.

[0121] In Comparative Example 2, silicon dioxide is selected as an abrasive and aluminum oxide is not included. The polishing rate MRR and surface roughness Ra of the aluminum alloy after polishing are low. This is because the first complexing agent with a short carbon chain and the second complexing agent with a long carbon chain can achieve a better complexing effect, but the first complexing agent with a short carbon chain cannot disperse the aluminum ions in the polishing process. Silicon dioxide and aluminum oxide are compounded in the abrasive and then react with the complexing agent, which can alleviate the shortcomings of the above-mentioned short carbon chain, obtain a better polishing effect, and make the product more stable. The abrasive in Comparative Example 2 does not contain aluminum oxide, so it cannot alleviate the shortcomings of the short carbon chain.

[0122] In contrast, in Example 3, a second complexing agent with a longer carbon chain length, which is commonly used, is selected to complex with aluminum ions, which produces a sustained release effect. The polishing rate MRR and surface roughness Ra of the aluminum alloy after polishing are low, and the polishing liquid is partially precipitated after standing for 150 days, and its stability is poor.

[0123] In summary, the present invention selects a first complexing agent with a short carbon chain and a second complexing agent with a long carbon chain to achieve a better complexing effect; and the silicon dioxide and aluminum oxide are compounded in the abrasive and then reacted with the complexing agent, which can alleviate the disadvantage that the short carbon chain cannot disperse the aluminum ions in the polishing process, and obtain a better polishing effect while making the product more stable.

[0124] Although the present invention has been described in detail above by means of general description, specific implementation methods and tests, it is obvious to those skilled in the art that some modifications or improvements may be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A chemical mechanical polishing liquid for aluminum alloy, It is characterized in that The raw materials for preparing the polishing liquid include the following components in terms of mass percentage: 20% to 30% abrasive, 1% to 5% oxidant, 0.01% to 1% complexing agent, 0.01% to 1% pH regulator, and the rest is deionized water; Wherein, the complexing agent is a mixture of a first complexing agent and a second complexing agent, the first complexing agent is a short-chain organic acid with 2 to 4 carbon atoms, and the second complexing agent is a long-chain organic acid with 8 to 10 carbon atoms; The abrasive is a mixture of aluminum oxide and silicon dioxide, and the silicon dioxide is a mixture with particle sizes of 10-40nm, 40-70nm and 90-110nm.

2. The aluminum alloy chemical mechanical polishing liquid according to claim 1, It is characterized in that The first complexing agent includes one or more of succinic acid, oxalic acid, glycine, citric acid, and ammonium malate.

3. The aluminum alloy chemical mechanical polishing liquid according to claim 1, It is characterized in that The second complexing agent includes one or more of suberic acid, alpha-carboxyisooctanoic acid, and 2-carboxy-4-isopropyl-3-pyrrolidineacetic acid.

4. The aluminum alloy chemical mechanical polishing liquid according to claim 1, It is characterized in that The mass ratio of the first complexing agent to the second complexing agent is 1:(1-10).

5. The aluminum alloy chemical mechanical polishing liquid according to claim 1, It is characterized in that The mass ratio of the silicon dioxide with particle sizes of 10-40nm, 40-70nm and 90-110nm is 1: (0.2-0.5): (0.02-0.05).

6. The aluminum alloy chemical mechanical polishing liquid according to claim 1, It is characterized in that The particle size of the aluminum oxide is 30nm-40nm; the mass ratio of the aluminum oxide to silicon dioxide is 1:(1-5).

7. The aluminum alloy chemical mechanical polishing liquid according to claim 1, It is characterized in that The oxidant includes one or more of hydrogen peroxide, phosphoric acid, sulfuric acid, nitric acid, acetic acid, and ammonium bifluoride.

8. The aluminum alloy chemical mechanical polishing liquid according to claim 1, It is characterized in that The pH of the polishing liquid is 9-10, and the pH regulator used includes inorganic acid and inorganic base. The inorganic acid includes hydrochloric acid, phosphoric acid or nitric acid, and the inorganic base includes potassium hydroxide or sodium hydroxide.

9. A method for preparing an aluminum alloy chemical mechanical polishing liquid according to any one of claims 1 to 8, It is characterized in that The following steps are involved: The abrasive, the complexing agent, the pH regulator and the oxidant are uniformly mixed to obtain the polishing liquid.

10. Use of the aluminum alloy chemical mechanical polishing liquid as claimed in any one of claims 1 to 8, It is characterized in that The aluminum alloy is polished using the polishing liquid.