A chemical mechanical polishing liquid, its preparation method and application

Abstract

The present invention provides a chemical mechanical polishing liquid, a preparation method thereof and an application. The chemical mechanical polishing liquid comprises: abrasive particles, an oxidizing agent, a corrosion inhibitor, a pH regulator, a polishing accelerator and water. By introducing a corrosion inhibitor into the chemical mechanical polishing liquid, the present invention can preferably inhibit the corrosion of gallium arsenide wafers and obtain a good polishing effect. The removal rate of gallium arsenide can reach 10,000 Å / min or more, the surface roughness after polishing can be as low as 0.32 nm, and the static corrosion rate can be as low as 125.31 Å / min. It can achieve a high polishing rate and good surface roughness, and at the same time has a low static corrosion rate and low production cost, realizing the efficient and stable polishing of gallium arsenide polishing liquid.

Description

Technical Field

[0001] The present invention belongs to the field of chemical reagents for semiconductor manufacturing, and particularly relates to a chemical mechanical polishing liquid, a preparation method thereof, and an application thereof. Background Art

[0002] Gallium arsenide is a second-generation semiconductor material of group III-V, with characteristics such as high electron mobility (8500 cm 2 / V·s) and band gap (1.43 eV). It is the most mature compound semiconductor material recognized internationally after "silicon" and is also one of the most important supporting materials in the optoelectronic and microelectronic industries. It is widely used in the manufacturing of integrated circuit fields such as high-frequency, high-speed, high-power, low-noise, high-temperature resistance, and radiation resistance, and has developed into a key technology for "modern electronic information products" and "information highways".

[0003] The surface quality of gallium arsenide wafers directly affects the performance and yield of devices. The better the surface quality of polished wafers, the higher the performance and yield of devices. Chemical mechanical polishing (CMP), as a common processing process for the fine processing of semiconductor material planarization, is considered the most effective processing method for achieving global planarization of materials currently. The CMP process is a combined process of the synergistic effect of chemical corrosion and mechanical grinding. In this process, the wafer is placed on a chemical mechanical polishing machine tool, and a certain downward pressure is applied to it, so that the wafer can mechanically rub against the rotating polishing pad; and an appropriate flow rate of polishing liquid is injected into it to form an easily removable corrosion oxide film on the wafer surface, and the planarization of the wafer is achieved under the synergistic effect of chemical film formation and mechanical film removal.

[0004] Currently, from the perspective of the removal mechanism of gallium arsenide, under the synergistic effect of mechanical force and chemical force, among which, the chemical effect has a more significant impact on the removal rate. When using conventional oxidants such as hydrogen peroxide and sodium hypochlorite for polishing, although a good polishing rate can be obtained, phenomena such as slight corrosion of the polished surface or severe corrosion of the unpolished surface usually occur during the polishing process, which greatly affects the yield of devices. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a chemical mechanical polishing liquid, a preparation method thereof, and an application thereof. The chemical mechanical polishing liquid is used for gallium arsenide polishing, and on the basis of achieving a high polishing rate and good surface roughness, it has a low static corrosion rate and low production cost.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a chemical mechanical polishing liquid, comprising: abrasive particles, an oxidant, a corrosion inhibitor, a pH regulator, a polishing promoter, and water;

[0008] The corrosion inhibitor is selected from at least one of nitrogen-containing five-membered heterocyclic compounds, amino alcohol compounds, amino acids or amino acid derivatives.

[0009] Preferably, the number of N atoms in the nitrogen-containing five-membered heterocyclic compound ≥ 3.

[0010] Preferably, the nitrogen-containing five-membered heterocyclic compound is a triazole compound with an electron-donating group, and the electron-donating group includes any one or more of amino, methyl or hydroxyl.

[0011] Preferably, the amino alcohol compound is an amino alcohol compound with a straight-chain main chain and the number of carbon atoms ≤ 8.

[0012] Preferably, the amino acid or amino acid derivative does not contain an electron-withdrawing group, and the electron-withdrawing group includes any one or more of carbonyl, acyl or ester group.

[0013] Preferably, the triazole compound with an electron-donating group is selected from at least one of 4-methyl-1H-benzotriazole, 5-methyl-benzotriazole, 5,6-dimethyl-1,2,3-benzotriazole, 1-hydroxybenzotriazole, 3-methyl-1H-1,2,4-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole or 3,5-diamino-1,2,4-triazole.

[0014] Preferably, the amino alcohol compound is selected from at least one of 2-diethylamino-1-ethanol, 2-dipropylaminoethanol, 2-dimethylamino-2-methyl-1-propanol, 1-dimethylamino-2-propanol, 2-amino-2-methyl-1-propanol, DL-2-amino-1-butanol, 2-amino-2-pentanol or 3-amino-4-octanol.

[0015] Preferably, the amino acid is selected from at least one of L-arginine, L-proline, methionine, L-serine or creatine.

[0016] Preferably, the amino acid derivative is selected from tris(hydroxymethyl)methylglycine.

[0017] Preferably, the abrasive particles are selected from at least one of modified silica, silica sol, fumed silica, alumina or cerium oxide.

[0018] Preferably, the particle size of the abrasive particles is 20 - 200 nm.

[0019] Preferably, the modified silica is obtained by modifying silica with a silane reagent, and the zeta potential of the modified silica under acidic conditions > 30 mV.

[0020] Preferably, the silane reagent is selected from 3-aminopropyltrimethoxysilane.

[0021] Preferably, the mass ratio of the silica to the silane reagent is (750 - 1000):5.

[0022] Preferably, the polishing accelerator includes at least one of sodium nitrate, potassium nitrate or ammonium nitrate.

[0023] Preferably, the oxidant is a peroxide, and the peroxide includes at least one of hydrogen peroxide, sodium peroxide, ammonium persulfate or peracetic acid.

[0024] Preferably, the pH regulator includes a pH acid regulator or a pH base regulator. The pH acid regulator includes organic acids and / or inorganic acids. The inorganic acids are selected from at least one of hydrochloric acid, nitric acid or sulfuric acid. The organic acids are selected from at least one of succinic acid, malonic acid, tartaric acid or gluconic acid. The pH base regulator includes potassium hydroxide and / or sodium hydroxide.

[0025] Preferably, the pH value of the chemical mechanical polishing liquid is 3 - 5.

[0026] Preferably, the chemical mechanical polishing liquid further includes an auxiliary agent, and the auxiliary agent includes a bacteriostatic agent and / or a dispersant.

[0027] Preferably, the mass percentage content of the abrasive particles in the chemical mechanical polishing liquid is 0.5 - 30 wt%.

[0028] More preferably, the mass percentage content of the abrasive particles in the chemical mechanical polishing liquid is 0.5 - 20 wt%.

[0029] Preferably, the mass percentage content of the oxidant in the chemical mechanical polishing liquid is 0.5 - 10 wt%.

[0030] More preferably, the mass percentage content of the oxidant in the chemical mechanical polishing liquid is 3 - 7 wt%.

[0031] Preferably, the mass percentage content of the corrosion inhibitor in the chemical mechanical polishing liquid is 0.025 - 0.3 wt%.

[0032] More preferably, the mass percentage content of the corrosion inhibitor in the chemical mechanical polishing liquid is 0.025 - 0.1 wt%.

[0033] Preferably, the mass percentage content of the polishing accelerator in the chemical mechanical polishing liquid is 0.2 - 5 wt%.

[0034] More preferably, the mass percentage content of the polishing promoter in the chemical mechanical polishing liquid is 0.5 - 2 wt%.

[0035] Preferably, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 4-amino-1,2,4-triazole, potassium nitrate, water and a pH regulator;

[0036] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 4-amino-1,2,4-triazole, sodium nitrate, water and a pH regulator;

[0037] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 5-methylbenzotriazole, ammonium nitrate, water and a pH regulator;

[0038] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, sodium nitrate, water and a pH regulator;

[0039] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, potassium nitrate, water and a pH regulator;

[0040] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 3-amino-1,2,4-triazole, ammonium nitrate, water and a pH regulator;

[0041] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 3-amino-1,2,4-triazole, sodium nitrate, water and a pH regulator;

[0042] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, potassium nitrate, water and a pH regulator;

[0043] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, ammonium nitrate, water and a pH regulator;

[0044] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, L-arginine, ammonium nitrate, water and a pH regulator;

[0045] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, L-arginine, sodium nitrate, water and a pH regulator;

[0046] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, L-proline, potassium nitrate, water and a pH regulator;

[0047] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, L-proline, ammonium nitrate, water and a pH regulator;

[0048] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, methionine, sodium nitrate, water and a pH regulator;

[0049] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, methionine, potassium nitrate, water and a pH regulator;

[0050] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, L-serine, ammonium nitrate, water and a pH regulator;

[0051] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, L-serine, sodium nitrate, water and a pH regulator;

[0052] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, creatine, potassium nitrate, water and a pH regulator;

[0053] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, creatine, ammonium nitrate, water and a pH regulator;

[0054] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, tris(hydroxymethyl)methylglycine, sodium nitrate, water and a pH regulator;

[0055] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, tris(hydroxymethyl)methylglycine, potassium nitrate, water and a pH regulator;

[0056] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, 2-amino-2-methyl-1-propanol, potassium nitrate, water and a pH regulator;

[0057] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, DL-2-amino-1-butanol, sodium nitrate, water and a pH regulator;

[0058] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, DL-2-amino-1-butanol, potassium nitrate, water and a pH regulator;

[0059] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, 3-amino-4-octanol, ammonium nitrate, water and a pH regulator;

[0060] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, 3-amino-4-octanol, sodium nitrate, water and a pH regulator;

[0061] Alternatively, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, methionine, ammonium nitrate, water and a pH regulator;

[0062] Alternatively, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 2-aminobenzimidazole, sodium nitrate, water and a pH regulator;

[0063] Alternatively, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, ammonium nitrate, water and a pH regulator;

[0064] Alternatively, the chemical mechanical polishing liquid comprises modified silica abrasive particles, hydrogen peroxide, L-arginine, sodium nitrate, water and a pH regulator;

[0065] Alternatively, the chemical mechanical polishing liquid comprises modified silica abrasive particles, hydrogen peroxide, 2-amino-2-methyl-1-propanol, potassium nitrate, water and a pH regulator;

[0066] Alternatively, the chemical mechanical polishing liquid comprises modified silica abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, ammonium nitrate, water and a pH regulator;

[0067] Alternatively, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, creatine, sodium nitrate, water and a pH regulator.

[0068] In a second aspect, the present invention further provides a method for preparing the above chemical mechanical polishing liquid, comprising the following steps:

[0069] Mix the abrasive particles, oxidant, corrosion inhibitor, polishing accelerator and water evenly, and then adjust the pH value with a pH regulator to obtain the chemical mechanical polishing liquid.

[0070] In a third aspect, the present invention also provides an application of the above chemical mechanical polishing liquid in polishing a gallium arsenide wafer.

[0071] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0072] By introducing a corrosion inhibitor, the chemical mechanical polishing liquid provided by the present invention can preferably inhibit the corrosion of the gallium arsenide wafer and obtain good polishing results. The removal rate of gallium arsenide can reach 10,000 Å / min or more, the surface roughness after polishing can be as low as 0.32 nm, and the static corrosion rate can be as low as 125.31 Å / min.

[0073] Furthermore, for the chemical mechanical polishing liquid provided by the present invention, when the concentration of abrasive particles is reduced from 20% to 1%, the removal rate can still be maintained above 80%. On the basis of cost savings, most of the process requirements can still be met. In addition, the content of abrasive particles in the chemical mechanical polishing liquid of the present invention can be as low as 1%, which can save about 90% of the cost, and the particle residue on the polished surface is significantly reduced, thereby reducing surface contaminants.

[0074] In summary, the chemical mechanical polishing liquid provided by the present invention can obtain a lower static corrosion rate, provide a higher gallium arsenide removal rate and good post-polishing roughness, thereby improving the surface condition of the polished wafer. Description of the Drawings

[0075] Figure 1 It is a photograph of a gallium arsenide wafer after static corrosion test in the polishing liquid of Comparative Example 16;

[0076] Figure 2 It is a photograph of a gallium arsenide wafer after static corrosion test in the polishing liquid of Example 24;

[0077] Figure 3 It is a schematic diagram of the roughness result of the surface of an unpolished gallium arsenide wafer tested by a Nanosurf atomic force microscope;

[0078] Figure 4 It is a schematic diagram of the roughness result of the surface of a gallium arsenide wafer polished with the polishing liquid of Comparative Example 6 tested by a Nanosurf atomic force microscope;

[0079] Figure 5 It is a GaAsSER diagram obtained when the corrosion inhibitor in the chemical mechanical polishing liquid is different nitrogen-containing heterocyclic compounds;

[0080] Figure 6 It is a GaAs SER diagram obtained when the corrosion inhibitor in the chemical mechanical polishing liquid is different amino acids or amino acid derivatives;

[0081] Figure 7 It is a GaAs SER diagram obtained when the corrosion inhibitor in the chemical mechanical polishing liquid is different amino alcohols;

[0082] Figure 8 It is a schematic diagram of the roughness result of the surface of a gallium arsenide wafer polished with the polishing liquid of Example 32 tested by a Nanosurf atomic force microscope;

[0083] Figure 9 It is a schematic diagram of the roughness result of the surface of a gallium arsenide wafer polished with the polishing liquid of Example 37 tested by a Nanosurf atomic force microscope;

[0084] Figure 10Schematic diagram of the roughness result of the surface of a gallium arsenide wafer polished with the polishing liquid of Example 38 after being tested by a Nanosurf atomic force microscope;

[0085] Figure 11 Schematic diagram of the roughness result of the surface of a gallium arsenide wafer polished with the polishing liquid of Example 24 after being tested by a Nanosurf atomic force microscope;

[0086] Figure 12 Comparison chart of particle size distributions of Example 37 and Example 38 after being placed in an oven at 55 °C for 28 days. Detailed implementation manners

[0087] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0088] The present invention provides a chemical mechanical polishing liquid for gallium arsenide wafers, which contains: abrasive particles, oxidants, corrosion inhibitors, pH regulators, polishing accelerators and water.

[0089] In the present invention, the abrasive particles are used to provide abrasive mechanical force for the chemical mechanical polishing liquid, lubricate the polishing pad and the wafer surface, and at the same time serve as a carrier for transporting the polishing accelerator. The abrasive particles can specifically be selected from at least one of modified silica, silica sol, fumed silica, alumina or cerium oxide, and preferably modified silica.

[0090] For modified silica, the present invention can take 10 g of modified silica sample, adjust the pH to acidic (pH is 3.0 - 5.0), and test the zeta potential to observe whether the modification is successful. Generally, when the zeta potential > 30 mV, it proves that the modification is successful. In this way, good stability of the colloid can be ensured.

[0091] In some embodiments of the present invention, the modified silica is obtained by modifying silica with a silane reagent, and more preferably by modifying silica sol with 3-aminopropyltrimethoxysilane. Its preparation method can be:

[0092] Weigh 750 - 1000 g of silica sol into a container, continuously stir, then take 5 g of 3-aminopropyltrimethoxysilane and dissolve it in an appropriate amount of methanol, and slowly drip it into the container within 30 min. Subsequently, continue to stir for 20 min.

[0093] The time and the amount of substances in the above preparation method can be adjusted as needed.

[0094] The present invention modifies the above-mentioned 3-aminopropyltrimethoxysilane on silica, and the obtained product is subjected to zeta potential test under acidic conditions (pH is 3.0 - 5.0). It is found that its zeta potential is greater than 30 mV, indicating successful modification.

[0095] It should be noted that after the present invention modifies silica sol with 3-(2-aminoethylamino)propylmethyldimethoxysilane and adjusts the pH to acidic, the silica sol agglomerates and cannot be used. Therefore, the selection of the above-mentioned 3-aminopropyltrimethoxysilane to modify silica sol in the present invention requires creative labor.

[0096] In the present invention, by mass percentage, the mass percentage content of the abrasive particles in the chemical mechanical polishing liquid is 0.5 - 30 wt%, preferably 0.5 - 20 wt%, and more preferably 1 - 5 wt%.

[0097] In the present invention, the particle size of the abrasive particles is 20 - 200 nm, preferably 50 - 120 nm. In some embodiments of the present invention, the particle size of the abrasive particles is 75 nm.

[0098] In the present invention, the oxidant can be at least one of peroxides such as hydrogen peroxide (also known as hydrogen dioxide), sodium peroxide, ammonium persulfate, peracetic acid, etc., and hydrogen peroxide is preferred.

[0099] In the present invention, by mass percentage, the mass percentage content of the oxidant in the chemical mechanical polishing liquid is 0.5 - 10 wt%, preferably 3 - 7 wt%.

[0100] In the present invention, the corrosion inhibitor is used for anti-corrosion, and specifically can be selected from at least one of nitrogen-containing five-membered heterocyclic compounds (N atoms ≥ 3), amino alcohol compounds, amino acids or amino acid derivatives.

[0101] In the present invention, the nitrogen-containing five-membered heterocyclic compound is a triazole compound with an electron-donating group. Preferably, the electron-donating group is an amino group, a methyl group, a hydroxyl group, etc. It should be noted that under acidic conditions, the surface of gallium arsenide usually has a large amount of positive charges. When the corrosion inhibitor surface has an electron-donating group, it can better generate electrostatic adsorption with the wafer surface, facilitate the formation of a protective film on the surface, and thus play a role in inhibiting corrosion.

[0102] In some embodiments of the present invention, the triazole compound with an electron-donating group is selected from at least one of 4-methyl-1H-benzotriazole, 5-methyl-benzotriazole, 5,6-dimethyl-1,2,3-benzotriazole, 1-hydroxybenzotriazole, 3-methyl-1H-1,2,4-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, or 3,5-diamino-1,2,4-triazole.

[0103] In the present invention, the amino alcohol compound is an amino alcohol compound with a straight-chain main chain and a carbon atom number ≤ 8. Compared with cyclic amino alcohols, it can ensure more effective contact with the wafer surface.

[0104] In some embodiments of the present invention, the amino alcohol compound is selected from at least one of 2-diethylamino-1-ethanol, 2-dipropylaminoethanol, 2-dimethylamino-2-methyl-1-propanol, 1-dimethylamino-2-propanol, 2-amino-2-methyl-1-propanol, DL-2-amino-1-butanol, 2-amino-2-pentanol, or 3-amino-4-octanol.

[0105] In the present invention, the amino acid or amino acid derivative does not contain an electron-withdrawing group. Preferably, the electron-withdrawing group is a carbonyl group, an acyl group, an ester group, etc.

[0106] In some embodiments of the present invention, the amino acid or amino acid derivative is selected from at least one of L-arginine, L-proline, methionine, L-serine, creatine, or tris(hydroxymethyl)methylglycine.

[0107] In the present invention, based on mass percentage, the mass percentage content of the corrosion inhibitor in the chemical mechanical polishing liquid is 0.025 - 0.3 wt%, preferably 0.025 - 0.1 wt%.

[0108] In the present invention, the pH regulator is used to adjust the pH value of the mechanical polishing liquid, including a pH acid regulator and a pH base regulator. The pH acid regulator includes organic acids and / or inorganic acids. The inorganic acid is selected from at least one of hydrochloric acid, nitric acid, or sulfuric acid. The organic acid is selected from at least one of succinic acid, malonic acid, tartaric acid, or gluconic acid. The pH base regulator includes potassium hydroxide and / or sodium hydroxide. The present invention preferably has the pH value of the chemical mechanical polishing liquid as 3 - 5, more preferably 3 - 4.

[0109] In the present invention, the polishing accelerator is at least one of sodium nitrate, potassium nitrate, or ammonium nitrate.

[0110] In the present invention, based on mass percentage, the mass percentage content of the polishing accelerator is 0.2 - 5 wt%, preferably 0.5 - 2 wt%.

[0111] In some technical solutions of the present invention, the chemical mechanical polishing liquid may further include auxiliary agents such as bacteriostatic agents and / or dispersants. The present invention has no particular limitation on the types of bacteriostatic agents and dispersants, and those well-known to those skilled in the art can be used.

[0112] In the present invention, the water is preferably deionized water.

[0113] In some preferred embodiments of the present invention, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, 4-amino-1,2,4-triazole, potassium nitrate, water, and a pH regulator;

[0114] Or, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, 4-amino-1,2,4-triazole, sodium nitrate, water, and a pH regulator;

[0115] Or, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, 5-methylbenzotriazole, ammonium nitrate, water, and a pH regulator;

[0116] Or, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, methyl-1H-benzotriazole, sodium nitrate, water, and a pH regulator;

[0117] Or, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, methyl-1H-benzotriazole, potassium nitrate, water, and a pH regulator;

[0118] Or, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, 3-amino-1,2,4-triazole, ammonium nitrate, water, and a pH regulator;

[0119] Or, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, 3-amino-1,2,4-triazole, sodium nitrate, water, and a pH regulator;

[0120] Or, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, 1-hydroxybenzotriazole, potassium nitrate, water, and a pH regulator;

[0121] Or, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, 1-hydroxybenzotriazole, ammonium nitrate, water, and a pH regulator;

[0122] Or, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, L-arginine, ammonium nitrate, water, and a pH regulator;

[0123] Or, the chemical mechanical polishing liquid includes silica abrasive grains, hydrogen peroxide, L-arginine, sodium nitrate, water, and a pH regulator;

[0124] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, L-proline, potassium nitrate, water and a pH regulator;

[0125] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, L-proline, ammonium nitrate, water and a pH regulator;

[0126] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, methionine, sodium nitrate, water and a pH regulator;

[0127] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, methionine, potassium nitrate, water and a pH regulator;

[0128] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, L-serine, ammonium nitrate, water and a pH regulator;

[0129] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, L-serine, sodium nitrate, water and a pH regulator;

[0130] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, creatine, potassium nitrate, water and a pH regulator;

[0131] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, creatine, ammonium nitrate, water and a pH regulator;

[0132] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, tris(hydroxymethyl)methylglycine, sodium nitrate, water and a pH regulator;

[0133] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, tris(hydroxymethyl)methylglycine, potassium nitrate, water and a pH regulator;

[0134] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 2-amino-2-methyl-1-propanol, potassium nitrate, water and a pH regulator;

[0135] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, DL-2-amino-1-butanol, sodium nitrate, water and a pH regulator;

[0136] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, DL-2-amino-1-butanol, potassium nitrate, water and a pH regulator;

[0137] Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 3-amino-4-octanol, ammonium nitrate, water and a pH regulator;

[0138] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, 3-amino-4-octanol, sodium nitrate, water and a pH regulator;

[0139] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, methionine, ammonium nitrate, water and a pH regulator;

[0140] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, 2-aminobenzimidazole, sodium nitrate, water and a pH regulator;

[0141] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, methyl-1H-benzotriazole, ammonium nitrate, water and a pH regulator;

[0142] Or, the chemical mechanical polishing liquid comprises modified silica abrasive grains, hydrogen peroxide, L-arginine, sodium nitrate, water and a pH regulator;

[0143] Or, the chemical mechanical polishing liquid comprises modified silica abrasive grains, hydrogen peroxide, 2-amino-2-methyl-1-propanol, potassium nitrate, water and a pH regulator;

[0144] Or, the chemical mechanical polishing liquid comprises modified silica abrasive grains, hydrogen peroxide, 1-hydroxybenzotriazole, ammonium nitrate, water and a pH regulator;

[0145] Or, the chemical mechanical polishing liquid comprises silica abrasive grains, hydrogen peroxide, creatine, sodium nitrate, water and a pH regulator.

[0146] In some specific embodiments of the present invention, the chemical mechanical polishing liquid specifically comprises:

[0147] 1 wt% of silica abrasive grains with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of 4-amino-1,2,4-triazole, 1 wt% of potassium nitrate, and the pH is 4;

[0148] 1 wt% of silica abrasive grains with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 4-amino-1,2,4-triazole, 1 wt% of sodium nitrate, and the pH is 4;

[0149] 1 wt% of silica abrasive grains with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of 5-methylbenzotriazole, 1 wt% of ammonium nitrate, and the pH is 4;

[0150] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 5-methylbenzotriazole, 1 wt% of ammonium nitrate, pH is 4;

[0151] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of methyl-1H-benzotriazole, 1 wt% of sodium nitrate, pH is 4;

[0152] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of methyl-1H-benzotriazole, 1 wt% of potassium nitrate, pH is 4;

[0153] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of 3-amino-1,2,4-triazole, 1 wt% of ammonium nitrate, pH is 4;

[0154] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 3-amino-1,2,4-triazole, 1 wt% of sodium nitrate, pH is 4;

[0155] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of 1-hydroxybenzotriazole, 1 wt% of potassium nitrate, pH is 4;

[0156] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 1-hydroxybenzotriazole, 1 wt% of ammonium nitrate, pH is 4;

[0157] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of L-arginine, 1 wt% of ammonium nitrate, pH is 4;

[0158] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of L-arginine, 1 wt% of sodium nitrate, pH is 4;

[0159] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of L-proline, 1 wt% of potassium nitrate, pH is 4;

[0160] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of L-proline, 1 wt% of ammonium nitrate, pH is 4;

[0161] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of methionine, 1 wt% of sodium nitrate, pH is 4;

[0162] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of methionine, 1 wt% of potassium nitrate, pH is 4;

[0163] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of L-serine, 1 wt% of ammonium nitrate, pH is 4;

[0164] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of L-serine, 1 wt% of sodium nitrate, pH is 4;

[0165] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of creatine, 1 wt% of potassium nitrate, pH is 4;

[0166] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of creatine, 1 wt% of ammonium nitrate, pH is 4;

[0167] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of tris(hydroxymethyl)methylglycine, 1 wt% of sodium nitrate, pH is 4;

[0168] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of tris(hydroxymethyl)methylglycine, 1 wt% of potassium nitrate, pH is 4;

[0169] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of 2-amino-2-methyl-1-propanol, 1 wt% of potassium nitrate, pH is 4;

[0170] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 2-amino-2-methyl-1-propanol, 1 wt% of potassium nitrate, pH is 4;

[0171] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of DL-2-amino-1-butanol, 1 wt% of sodium nitrate, pH is 4;

[0172] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of DL-2-amino-1-butanol, 1 wt% of potassium nitrate, pH is 4;

[0173] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of 3-amino-4-octanol, 1 wt% of ammonium nitrate, pH is 4;

[0174] 1 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 3-amino-4-octanol, 1 wt% of sodium nitrate, pH is 4;

[0175] 20 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of 3-amino-1,2,4-triazole, 1 wt% of ammonium nitrate, pH is 4;

[0176] 20 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of methionine, 0.8 wt% of ammonium nitrate, pH is 4;

[0177] 10 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 5-methyl-benzotriazole, 1.2 wt% of sodium nitrate, pH is 4;

[0178] 20 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 2-amino-2-methyl-1-propanol, 1 wt% of potassium nitrate, pH is 4;

[0179] 10 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of L-arginine, 1.2 wt% of sodium nitrate, pH is 4;

[0180] 5 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 2-amino-2-methyl-1-propanol, 1 wt% of potassium nitrate, pH is 4;

[0181] 5 wt% of silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of methyl-1H-benzotriazole, 0.8 wt% of ammonium nitrate, pH is 4;

[0182] 5 wt% of modified silica grinding particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of L-arginine, 1.2 wt% of sodium nitrate, pH is 4;

[0183] 5 wt% of silica abrasive particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 2-amino-2-methyl-1-propanol, 1 wt% of potassium nitrate, pH is 4;

[0184] 5 wt% of modified silica abrasive particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 2-amino-2-methyl-1-propanol, 1 wt% of potassium nitrate, pH is 4;

[0185] 1 wt% of silica abrasive particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of DL-2-amino-1-butanol, 1.2 wt% of sodium nitrate, pH is 4;

[0186] 1 wt% of modified silica abrasive particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.1 wt% of 1-hydroxybenzotriazole, 1.4 wt% of ammonium nitrate, pH is 4;

[0187] 1 wt% of silica abrasive particles with a particle size of 75 nm, 5 wt% of hydrogen peroxide, 0.025 wt% of creatine, 1 wt% of sodium nitrate, pH is 4.

[0188] In the formula of the above chemical mechanical polishing liquid, after the dosage of each component is determined and the target pH is obtained, the balance is water.

[0189] The present invention also provides a preparation method of a chemical mechanical polishing liquid, which can be obtained by the following method:

[0190] Mix the abrasive particles, oxidant, corrosion inhibitor, polishing promoter and water evenly, and then adjust to the target pH value with a pH regulator to obtain the chemical mechanical polishing liquid.

[0191] Preferably, first add deionized water and various components except the abrasive particles and the pH regulator into a container and stir evenly, then add a certain amount of abrasive particles, stir evenly, and adjust to the required pH value with the pH regulator.

[0192] The above chemical polishing liquid provided by the present invention can be applied to the polishing of gallium arsenide wafers. Preferably, the polishing parameters are as follows: the down pressure is 6.0 psi, the flow rate is 100 mL / min, the rotation speed of the polishing pad is 50 rpm, the rotation speed of the polishing head is 60 rpm, the polishing time is 30 min, and the polishing liquid is recycled. The polishing pad is suba 400.

[0193] After testing, it is found that the chemical mechanical polishing liquid can better inhibit the corrosion of gallium arsenide wafers and obtain good polishing results. The removal rate of gallium arsenide can reach 10,000 Å / min or more, the surface roughness after polishing can be as low as 0.32 nm, and the static corrosion rate can be as low as 125.31 Å / min. At the same time, for the polishing liquid provided by the present invention, when the concentration of abrasive particles is reduced from 20% to 1%, the removal rate can still be maintained above 80%, and most of the process requirements can still be met on the basis of cost savings. In addition, the content of abrasive particles in the polishing liquid of the present invention can be as low as 1%, which can save about 90% of the cost, and the particle residue on the surface after polishing is significantly reduced, thereby reducing surface contaminants.

[0194] In summary, the present invention provides a chemical mechanical polishing liquid suitable for gallium arsenide wafers, which has a high polishing rate, good surface roughness, low static corrosion rate and low production cost, and realizes efficient and stable polishing of gallium arsenide polishing liquid.

[0195] To further illustrate the present invention, the following examples are used for detailed description. The experimental raw materials used in the following examples of the present invention are generally commercially available products.

[0196] Static etch rate (SER): The chemical mechanical polishing liquids of the following comparative examples and examples were placed in a 50°C water bath, and the wafers were immersed in the polishing liquid for 30 min. The surface state of the wafers before the static corrosion test was good.

[0197] The surface roughness (Ra) was measured by a Nanosurf Alphacen 300 Flex atomic force microscope, and the material removal rate (MRR) was calculated by weighing the masses (m1, m2) of the wafers before and after polishing with a precision electronic balance, and then calculated by the following formula:

[0198] MRR = (m1 – m2) / (ρ × A × t);

[0199] Wherein, m1 is the mass of the wafer before polishing, m2 is the mass of the wafer after polishing, ρ is the density of the gallium arsenide wafer, 5.32 g / cm 2 ; A is the area of the gallium arsenide wafer, 4 cm 2 (4 square wafers of 1 cm); t is the polishing time, 30 min.

[0200] The Zeta potential was measured by the zeta potential module of a Nicomp 3000 series nano laser particle size analyzer, and the particle size of the abrasive particles was measured by a CPS disc centrifugal nano particle size analyzer.

[0201] The modified SiO2 involved in the following examples was prepared according to the following method:

[0202] Weigh 750 g of silica sol into a container and continuously stir. Then, dissolve 5 g of 3-aminopropyltrimethoxysilane in an appropriate amount of methanol and slowly add it dropwise into the container, completing within 30 min. Subsequently, continue stirring for 20 min. Take 10 g of the sample, adjust the pH to 4.0, and measure the zeta potential. It is found that the zeta potential is 48.6 mV, which is greater than 30 mV, indicating successful modification.

[0203] Examples 1 - 41

[0204] The formulations of the chemical mechanical polishing fluids of Examples 1 - 41 are shown in Table 1-1 (Examples 1 - 8) and Table 1-2 (Examples 9 - 41) as follows:

[0205] Table 1-1

[0206]

[0207] Table 1-2

[0208]

[0209] The specific preparation method is as follows:

[0210] Mix various materials uniformly with water in proportion, and then adjust to the appropriate pH value with a pH regulator. After standing for 30 min, the polishing fluid is obtained, with continuous stirring during this period.

[0211] Comparative Examples 1 - 40

[0212] The formulations of the chemical mechanical polishing fluids of Comparative Examples 1 - 40 are shown in Table 2, and the preparation method refers to Examples 1 - 41:

[0213] Table 2

[0214]

[0215] The corrosion test results and polishing results of the above Examples and Comparative Examples are shown in Table 3-1 (Comparative Examples 1 - 25) and Table 3-2 (Comparative Examples 26 - 40 and Examples 1 - 29, Example 32, Example 33, Examples 36 - 38, Examples 40 - 41) as follows:

[0216] Table 3-1

[0217]

[0218] Table 3-2

[0219]

[0220] From the results of Comparative Examples 1 to 8, it can be seen that after adding 1 wt% hydrogen peroxide, only under acidic and weakly acidic conditions will the gallium arsenide wafer not be corroded; under alkaline conditions, the surface and backside corrosion generated during the polishing process is difficult to remove through the CMP process, which has a greater impact on subsequent processes, or the wafer may be scrapped due to irreversible corrosion, as shown in Figure 1 ; when Comparative Example 6 is used for gallium arsenide polishing, although the backside of the crystal is corroded, the surface roughness is reduced significantly, as shown in Figure 4 . From the results of Comparative Examples 9 to 15, it can be seen that under alkaline conditions, the gallium arsenide wafer will not be corroded only when the concentration of hydrogen peroxide used is lower than 0.05 wt%, but at this time, the concentration of the oxidant is low and the chemical action is weak; similarly, adding sodium hypochlorite with different concentrations under alkaline conditions also causes the gallium arsenide wafer to be corroded.

[0221] Before polishing, the surface roughness of the gallium arsenide wafer is dozens or even hundreds of nanometers, and the planarization degree is very poor, as shown in Figure 3 . In Comparative Example 1, after adding 1 wt% hydrogen peroxide, due to the imbalance between the chemical force and the mechanical force, the surface of gallium arsenide shows an obvious foggy appearance after polishing. In addition, after polishing using the above comparative examples, the removal rate of gallium arsenide is relatively low, which cannot meet the requirements, and the chemical force needs to be further improved.

[0222] In summary, in the following examples, an acidic polishing solution is still selected as the corrosion inhibitor for gallium arsenide polishing.

[0223] Under acidic conditions, after adding a higher concentration of hydrogen peroxide, adding 250 - 1000 ppm of unbranched triazole compounds (Comparative Examples 17 - 20) does not play a role in inhibiting the SER value; similarly, reagents such as tetrazole, imidazole, and pyridazine (six-membered ring), even with electron-donating groups such as amino and mercapto, cannot inhibit the corrosion of gallium arsenide wafers (Comparative Examples 21 - 32); after adding 250 - 1000 ppm of triazole compounds with electron-donating groups (such as amino, methyl, and hydroxyl) (Examples 1 - 10), the corrosion of gallium arsenide wafers can be better inhibited, as shown in Figure 5 .

[0224] When the addition amount is 250 - 1000 ppm, when the amino acid used has an electron-withdrawing group (such as carbonyl, acyl, and ester groups), a relatively high SER value will be obtained (Comparative Examples 33 - 36), and the corrosion effect cannot be inhibited; while when the amino acid used has an electron-donating group (such as amino, methyl, hydroxyl, methylthio, and hydroxymethyl), it can inhibit the corrosion of the wafer (Examples 11 - 22). At the same time, when the concentration of the amino acid is increased, the effect of the above compounds is also enhanced, as shown in Figure 6 .

[0225] In the present invention, amino alcohol is used as a corrosion inhibitor. The structural formula contains an electron-donating group, amino, which can more significantly reduce the corrosion effect. Whether at low concentration or high concentration, amino alcohols with shorter main carbon chain structures can significantly reduce the SER value of GaAs under acidic conditions, enabling a smoother and mirror-like surface state to be obtained under polishing conditions. When the carbon chain of such compounds is further lengthened, the corrosion inhibition effect decreases accordingly, as shown in Figure 7 .

[0226] The difference between Comparative Example 37 and Comparative Example 40 lies only in the type of polishing accelerator. In Comparative Example 40, iron nitrate is used as the polishing accelerator, with a low removal rate and a high surface roughness, indicating that when the cation in the nitrate is a metal ion with strong oxidizing properties, it is not suitable for the polishing of gallium arsenide.

[0227] Comparative Example 38 does not contain an oxidant and contains 1 wt% of the polishing accelerator potassium nitrate. The removal rate of gallium arsenide is 4560.7 Å / min, and the surface roughness is 1.81 nm. Comparative Example 39 contains an oxidant and no polishing accelerator. The removal rate of gallium arsenide is 2566.7 Å / min, and the surface roughness is 4.25 nm. Example 24 contains both an oxidant and 1 wt% of the polishing accelerator potassium nitrate. The removal rate of gallium arsenide is 8330 Å / min, showing a significant increase, and the surface roughness is 0.59 nm (see Figure 11 ), showing an obvious improvement. It can be seen that the oxidant and the polishing accelerator show a synergistic effect on the improvement of the removal rate of gallium arsenide and the surface roughness.

[0228] The difference between Comparative Example 37 and Comparative Example 39 lies in the presence or absence of the polishing accelerator. Compared with Comparative Example 39, the removal rate of gallium arsenide in Comparative Example 37 increases from 2566.7 Å / min to 6140 Å / min. However, due to the lack of an effect of uniform thickness reduction, the surface roughness is still relatively high.

[0229] The difference between Comparative Example 37 and Example 24 lies only in the content of the polishing accelerator potassium nitrate. In Comparative Example 37, the addition amount of potassium nitrate is 0.1 wt%, while in Example 24, the addition amount of the polishing accelerator is 1 wt%. The removal rate of gallium arsenide increases to 8330 Å / min, and at the same time, the surface roughness also remains at a low level.

[0230] Comparative Example 39 contains an oxidizing agent and no polishing accelerator, with a gallium arsenide removal rate of 2566.7 Å / min and a surface roughness of 4.25 nm; Comparative Example 38 contains no oxidizing agent and 1 wt% polishing accelerator potassium nitrate, with a gallium arsenide removal rate of 4560.7 Å / min and a surface roughness of 1.81 nm; Example 24 contains both an oxidizing agent and 1 wt% polishing accelerator potassium nitrate, with a gallium arsenide removal rate of 8330 Å / min, showing a significant increase, and a surface roughness of 0.59 nm, showing obvious improvement; from this, it can be seen that the oxidizing agent and the polishing accelerator show a synergistic effect on the improvement of the gallium arsenide removal rate and the surface roughness.

[0231] In Examples 24 and 40, the content of SiO2 was reduced to 1 wt%, however, in the case of containing an oxidizing agent and a polishing accelerator, a relatively high material removal rate could still be maintained; in Examples 29 and 32, when the content of SiO2 was increased to 20 wt% in the case of containing an oxidizing agent and a polishing accelerator, the material removal rates were increased to 11038 Å / min and 11200 Å / min, and using any of the corrosion inhibitors screened out in Examples 1 to 28 within the concentration range of 0.025 to 0.1 wt% would not affect the removal rate.

[0232] In summary, adding sodium nitrate, potassium nitrate or ammonium nitrate as a polishing accelerator to the polishing liquid containing an oxidizing agent, the two can play a synergistic role, significantly improving the gallium arsenide removal rate and reducing the surface roughness. The polishing accelerators sodium nitrate, potassium nitrate or ammonium nitrate have a relatively high ion concentration. After adding, the electric double layer of the abrasive particles is compressed to a certain extent, making the charge carried on the surface of the abrasive particles have a stronger electrostatic adsorption effect with the charge carried on the surface of gallium arsenide, thereby increasing the material removal rate. However, the addition of the polishing accelerator to enhance the ionic strength also has a negative impact on the stability of the polishing liquid. The higher the ionic strength in the polishing liquid, the stronger the shielding effect on the surface potential of the particles, resulting in a decrease in the zeta potential of the abrasive particles, thereby reducing the shelf life of the polishing liquid.

[0233] Therefore, in the present invention, 3-aminopropyltrimethoxysilane was used to modify the silica sol. After the SiO2 abrasive particles in Examples 36, 38, and 40 were modified, when the pH was 3, the measured zeta potential was 46.8 mV, in a very stable state. After being placed in an oven at 55 °C for 28 days, that is, it can be placed at room temperature for about 224 days, and the particle size of the abrasive particles did not further increase (see Figure 12), and the polishing performance remains unchanged. While in Example 37, it can only be stored for about 50 days at room temperature, indicating that after the modification of the abrasive particles, the shelf life of the polishing liquid can be further extended without reducing the removal rate of gallium arsenide. However, after modifying the silica sol with 3-(2-aminoethylamino)propylmethyldimethoxysilane and adjusting the pH to acidic in the present invention, the silica sol agglomerates and cannot be used.

[0234] When the polishing liquid provided by the present invention is used for polishing gallium arsenide, a removal rate higher than 8000 Å / min can be obtained and the mirror surface is bright (the effect is shown in Figure 2 ), with a surface state of low roughness. When the concentration of the abrasive particles is further reduced from 20 wt% to 1 wt%, nearly 90% of the cost can be saved at this time, and the removal rate still remains above 80%. On the basis of cost savings, most of the process requirements can still be met.

[0235] In addition, in Examples 32, 37, and 38, when using higher concentrations or modified abrasive particles, good surface roughness can also be obtained, which are 0.32 nm, 0.47 nm, and 0.57 nm respectively (see Figure 8 , 9 and 10).

[0236] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A chemical mechanical polishing liquid for a gallium arsenide wafer, characterized in that, It consists of the following components: abrasive particles, an oxidizing agent, a corrosion inhibitor, a pH regulator, a polishing accelerator, and water; The corrosion inhibitor is selected from at least one of nitrogen-containing five-membered heterocyclic compounds, amino alcohol compounds, amino acids, or amino acid derivatives; The number of N atoms in the nitrogen-containing five-membered heterocyclic compound is ≥3; The nitrogen-containing five-membered heterocyclic compound is a triazole compound with an electron-donating group, and the electron-donating group includes any one or more of amino, methyl, or hydroxyl; The amino alcohol compound is an amino alcohol compound with a straight-chain main chain and the number of carbon atoms ≤8; The amino acid or amino acid derivative does not contain an electron-withdrawing group, and the electron-withdrawing group includes any one or more of carbonyl, acyl, or ester group; The pH value of the chemical mechanical polishing liquid is 3-5; The polishing accelerator is at least one of sodium nitrate, potassium nitrate, or ammonium nitrate; 2. The chemical mechanical polishing liquid according to claim 1, wherein The abrasive particles are selected from at least one of modified silica, silica sol, fumed silica, alumina, or cerium oxide, and the particle size of the abrasive particles is 20-200 nm; And / or, the oxidizing agent is a peroxide, and the peroxide includes at least one of hydrogen peroxide, sodium peroxide, ammonium persulfate, or peracetic acid; 3. The chemical mechanical polishing liquid according to claim 2, wherein The zeta potential of the modified silica under acidic conditions >30 mV; And / or, the triazole compound with an electron-donating group is selected from at least one of 4-methyl-1H-benzotriazole, 5-methyl-benzotriazole, 5,6-dimethyl-1,2,3-benzotriazole, 1-hydroxybenzotriazole, 3-methyl-1H-1,2,4-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, or 3,5-diamino-1,2,4-triazole; And / or, the amino alcohol compound is selected from at least one of 2-diethylamino-1-ethanol, 2-dipropylaminoethanol, 2-dimethylamino-2-methyl-1-propanol, 1-dimethylamino-2-propanol, 2-amino-2-methyl-1-propanol, DL-2-amino-1-butanol, 2-amino-2-pentanol, or 3-amino-4-octanol; And / or, the amino acid is selected from at least one of L-arginine, L-proline, methionine, L-serine, or creatine; And / or, the amino acid derivative is selected from tris(hydroxymethyl)methylglycine; And / or, the pH regulator includes a pH acid regulator or a pH base regulator. The pH acid regulator includes an organic acid and / or an inorganic acid. The inorganic acid is selected from at least one of hydrochloric acid, nitric acid, or sulfuric acid. The organic acid is selected from at least one of succinic acid, malonic acid, tartaric acid, or gluconic acid. The pH base regulator includes potassium hydroxide and / or sodium hydroxide; 4. The chemical mechanical polishing liquid according to claim 3, wherein The modified silica is obtained by modifying silica with a silane reagent, and the zeta potential of the modified silica under acidic conditions >30 mV; The silane reagent is 3-aminopropyltrimethoxysilane; The mass ratio of the silica to the silane reagent is (750-1000):

5.

5. The chemical mechanical polishing liquid according to claim 1, wherein The chemical mechanical polishing liquid further includes an auxiliary agent, and the auxiliary agent includes a bacteriostatic agent and / or a dispersant.

6. The chemical mechanical polishing liquid according to claim 1, wherein By mass percentage, the mass percentage content of the abrasive particles in the chemical mechanical polishing liquid is 0.5 - 30 wt%; and / or, the mass percentage content of the oxidant in the chemical mechanical polishing liquid is 0.5 - 10 wt%; and / or, the mass percentage content of the corrosion inhibitor in the chemical mechanical polishing liquid is 0.025 - 0.3 wt%; and / or, the mass percentage content of the polishing accelerator in the chemical mechanical polishing liquid is 0.2 - 5 wt%.

7. The chemical mechanical polishing liquid according to claim 1, wherein By mass percentage, the mass percentage content of the abrasive particles in the chemical mechanical polishing liquid is 0.5 - 20 wt%; and / or, the mass percentage content of the oxidant in the chemical mechanical polishing liquid is 3 - 7 wt%; and / or, the mass percentage content of the corrosion inhibitor in the chemical mechanical polishing liquid is 0.025 - 0.1 wt%; and / or, the mass percentage content of the polishing accelerator in the chemical mechanical polishing liquid is 0.5 - 2 wt%.

8. The chemical mechanical polishing liquid according to claim 1, wherein The chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, 4-amino-1,2,4-triazole, potassium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, 4-amino-1,2,4-triazole, sodium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, 5-methylbenzotriazole, ammonium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, sodium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, potassium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, 3-amino-1,2,4-triazole, ammonium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, 3-amino-1,2,4-triazole, sodium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, potassium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, ammonium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, L-arginine, ammonium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, L-arginine, sodium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, L-proline, potassium nitrate, water and a pH regulator; or, the chemical mechanical polishing liquid includes silica abrasive particles, hydrogen peroxide, L-proline, ammonium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, methionine, sodium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, methionine, potassium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, L-serine, ammonium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, L-serine, sodium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, creatine, potassium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, creatine, ammonium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, tris(hydroxymethyl)methylglycine, sodium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, tris(hydroxymethyl)methylglycine, potassium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 2-amino-2-methyl-1-propanol, potassium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, DL-2-amino-1-butanol, sodium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, DL-2-amino-1-butanol, potassium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 3-amino-4-octanol, ammonium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 3-amino-4-octanol, sodium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, methionine, ammonium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, 2-aminobenzimidazole, sodium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, ammonium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises modified silica abrasive particles, hydrogen peroxide, L-arginine, sodium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises modified silica abrasive particles, hydrogen peroxide, 2-amino-2-methyl-1-propanol, potassium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises modified silica abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, ammonium nitrate, water and a pH regulator; Or, the chemical mechanical polishing liquid comprises silica abrasive particles, hydrogen peroxide, creatine, sodium nitrate, water and a pH regulator.

9. A method for preparing a chemical mechanical polishing liquid according to any one of claims 1 to 8, characterized in that, Comprising the following steps: After uniformly mixing the abrasive particles, the oxidant, the corrosion inhibitor, the polishing accelerator and water, adjusting the pH value with a pH regulator to obtain the chemical mechanical polishing liquid.

10. Use of the chemical mechanical polishing liquid according to any one of claims 1 to 8 or the chemical mechanical polishing liquid prepared by the preparation method according to claim 9 in polishing a gallium arsenide wafer.

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