Chemical mechanical polishing solution as well as preparation method and application thereof

Abstract

The invention provides a chemical mechanical polishing solution as well as a preparation method and application thereof. The chemical mechanical polishing liquid comprises grinding particles, an oxidizing agent, a corrosion inhibitor, a pH regulator, a polishing accelerant and water. By introducing the corrosion inhibitor into the chemical mechanical polishing solution, corrosion of gallium arsenide wafers can be well inhibited, a good polishing effect is obtained, the removal rate of gallium arsenide can reach 10000 / min or above, the surface roughness after polishing can be as low as 0.32 nm, the static corrosion rate can be as low as 125.31 / min, the high polishing rate and the good surface roughness can be achieved, and the chemical mechanical polishing solution can be applied to polishing of gallium arsenide wafers. And meanwhile, the gallium arsenide polishing solution has relatively low static corrosion rate and low production cost, and efficient and stable polishing of the gallium arsenide polishing solution is realized.

Description

Technical Field

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

[0002] Gallium arsenide is a second-generation semiconductor material of the III-V group with high electron mobility (8500 cm 2 / V·s) and bandgap width (1.43 eV). It is internationally recognized as the most mature compound semiconductor material after "silicon" and one of the most important supporting materials for optoelectronics and microelectronics industries. It is widely used in the manufacture of high-frequency, high-speed, high-power, low-noise, high-temperature resistant, and radiation-resistant integrated circuits, and has developed into a key technology for "modern electronic information products" and "information superhighway".

[0003] The surface quality of GaAs 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) is a common process for flattening and fine processing of semiconductor materials, and is considered to be the most effective processing method for achieving global flattening of materials. The CMP process is a combined process of the synergistic effects of chemical corrosion and mechanical grinding. The process places the wafer on a chemical mechanical polishing machine and applies a certain downward pressure to it, so that the wafer can be mechanically rubbed against the rotating polishing pad; and a polishing liquid with an appropriate flow rate is injected into it to form an easily removable corrosive oxide film on the surface of the wafer, and the wafer is flattened under the synergistic effect of chemical film formation and mechanical film removal.

[0004] At present, from the perspective of the removal mechanism of GaAs, under the synergistic effect of mechanical force and chemical force, 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, the polished surface is usually slightly corroded or the unpolished surface is severely corroded during the polishing process, which greatly affects the device yield. Summary of the invention

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

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

[0007] In a first aspect, the present invention provides a chemical mechanical polishing liquid, comprising: abrasive particles, an oxidant, a corrosion inhibitor, a pH adjuster, a polishing accelerator 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 is ≥3.

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

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

[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 a carbonyl group, an acyl group or an 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 and 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 is greater than 30 mV.

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

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

[0022] Preferably, the polishing accelerator comprises 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 comprises a pH acid regulator or a pH base regulator, the pH acid regulator comprises 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 comprises potassium hydroxide and / or sodium hydroxide.

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

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

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

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

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

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

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

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

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

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

[0035] Preferably, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, 4-amino-1,2,4-triazole, potassium nitrate, water and a pH adjuster;

[0036] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 4-amino-1,2,4-triazole, sodium nitrate, water and a pH adjuster;

[0037] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, 5-methylbenzotriazole, ammonium nitrate, water and a pH adjuster;

[0038] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, sodium nitrate, water and a pH adjuster;

[0039] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, potassium nitrate, water and a pH adjuster;

[0040] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 3-amino-1,2,4-triazole, ammonium nitrate, water and a pH adjuster;

[0041] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 3-amino-1,2,4-triazole, sodium nitrate, water and a pH adjuster;

[0042] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, potassium nitrate, water and a pH adjuster;

[0043] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, ammonium nitrate, water and a pH adjuster;

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

[0045] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, L-arginine, sodium nitrate, water and a pH adjuster;

[0046] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, L-proline, potassium nitrate, water and a pH adjuster;

[0047] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, L-proline, ammonium nitrate, water and a pH adjuster;

[0048] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, methionine, sodium nitrate, water and a pH adjuster;

[0049] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, methionine, potassium nitrate, water and a pH adjuster;

[0050] Or, the chemical mechanical polishing liquid comprises silicon dioxide abrasive particles, hydrogen peroxide, L-serine, ammonium nitrate, water and a pH adjuster;

[0051] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, L-serine, sodium nitrate, water and a pH adjuster;

[0052] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, creatine, potassium nitrate, water and a pH adjuster;

[0053] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, creatine, ammonium nitrate, water and a pH adjuster;

[0054] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, tris(hydroxymethyl)methylglycine, sodium nitrate, water and a pH adjuster;

[0055] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, tris(hydroxymethyl)methylglycine, potassium nitrate, water and a pH adjuster;

[0056] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 2-amino-2-methyl-1-propanol, potassium nitrate, water and a pH adjuster;

[0057] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, DL-2-amino-1-butanol, sodium nitrate, water and a pH adjuster;

[0058] Or, the chemical mechanical polishing liquid includes silicon dioxide abrasive particles, hydrogen peroxide, DL-2-amino-1-butanol, potassium nitrate, water and a pH adjuster;

[0059] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 3-amino-4-octanol, ammonium nitrate, water and a pH adjuster;

[0060] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 3-amino-4-octanol, sodium nitrate, water and a pH adjuster;

[0061] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, methionine, ammonium nitrate, water and a pH adjuster;

[0062] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, 2-aminobenzimidazole, sodium nitrate, water and a pH adjuster;

[0063] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, ammonium nitrate, water and a pH adjuster;

[0064] Or, the chemical mechanical polishing solution comprises modified silicon dioxide abrasive particles, hydrogen peroxide, L-arginine, sodium nitrate, water and a pH adjuster;

[0065] Or, the chemical mechanical polishing solution comprises modified silicon dioxide abrasive particles, hydrogen peroxide, 2-amino-2-methyl-1-propanol, potassium nitrate, water and a pH adjuster;

[0066] Or, the chemical mechanical polishing solution comprises modified silicon dioxide abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, ammonium nitrate, water and a pH adjuster;

[0067] Alternatively, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, creatine, sodium nitrate, water and a pH adjuster.

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

[0069] After the abrasive particles, oxidant, corrosion inhibitor, polishing accelerator and water are uniformly mixed, the pH value is adjusted by using a pH adjuster to obtain a chemical mechanical polishing liquid.

[0070] In a third aspect, the present invention further provides an application of the chemical mechanical polishing solution in polishing gallium arsenide-containing wafers.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] The chemical mechanical polishing liquid provided by the present invention can effectively inhibit the corrosion of gallium arsenide wafers by introducing corrosion inhibitors, and obtain good polishing results. The gallium arsenide removal rate can reach 10000 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, the chemical mechanical polishing liquid provided by the present invention can still maintain a removal rate of more than 80% when the concentration of abrasive particles is reduced from 20% to 1%, and can still meet most process requirements on the basis of cost savings. In addition, the abrasive particle content 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 surface after polishing is significantly reduced, thereby reducing surface pollutants.

[0074] In summary, the chemical mechanical polishing solution provided by the present invention can achieve a lower static corrosion rate, provide a higher gallium arsenide removal rate and good post-polishing roughness, thereby improving the surface condition of the wafer after polishing. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 This is a photograph of a gallium arsenide wafer after static corrosion testing in the polishing solution of Comparative Example 16;

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

[0077] Figure 3 Schematic diagram of the roughness results of the unpolished GaAs wafer surface tested by Nanosurf atomic force microscope;

[0078] Figure 4 This is a schematic diagram of the roughness results of the gallium arsenide wafer surface after being polished by the polishing liquid of comparative example 6 and tested by Nanosurf atomic force microscope;

[0079] Figure 5 The GaAsSER diagrams obtained when the corrosion inhibitor in the chemical mechanical polishing solution is different nitrogen-containing heterocyclic compounds;

[0080] Figure 6 SER diagrams of GaAs obtained when the corrosion inhibitor in the chemical mechanical polishing solution is different amino acids or amino acid derivatives;

[0081] Figure 7 The GaAs SER graphs obtained when the corrosion inhibitor in the chemical mechanical polishing solution is different amino alcohols;

[0082] Figure 8 This is a schematic diagram of the roughness results of the gallium arsenide wafer surface after polishing with the polishing solution of Example 32 tested by Nanosurf atomic force microscope;

[0083] Fig. 9 This is a schematic diagram of the roughness results of the gallium arsenide wafer surface after polishing with the polishing solution of Example 37 tested by Nanosurf atomic force microscope;

[0084] Fig.10This is a schematic diagram of the roughness results of the gallium arsenide wafer surface after polishing with the polishing solution of Example 38 tested by Nanosurf atomic force microscope;

[0085] Fig.11 This is a schematic diagram of the roughness results of the surface of the gallium arsenide wafer after polishing with the polishing solution of Example 24 tested by Nanosurf atomic force microscope;

[0086] Fig.12 This is a comparison chart of the particle size distribution of Example 37 and Example 38 after being placed in an oven at 55°C for 28 days. DETAILED DESCRIPTION

[0087] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0088] The invention provides a chemical mechanical polishing liquid for gallium arsenide wafers, which contains abrasive particles, an oxidant, a corrosion inhibitor, a pH regulator, a polishing accelerator and water.

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

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

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

[0092] Weigh 750-1000 g of silica sol into a container and stir continuously. Then take 5 g of 3-aminopropyltrimethoxysilane and dissolve it in an appropriate amount of methanol. Slowly add it dropwise into the container within 30 min. Then continue stirring for 20 min.

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

[0094] The present invention modifies silicon dioxide with the 3-aminopropyltrimethoxysilane, and the obtained product is tested for zeta potential under acidic conditions (pH 3.0-5.0), and it is found that the zeta potential is greater than 30 mV, indicating that the modification is successful.

[0095] It should be noted that after the present invention uses 3-(2-aminoethylamino)propylmethyldimethoxysilane to modify the silica sol, after the pH is adjusted to acidic, the silica sol agglomerates and cannot be used. Therefore, the present invention selects the above-mentioned 3-aminopropyltrimethoxysilane to modify the silica sol, which requires creative labor.

[0096] In the present invention, the mass percentage 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 to 200 nm, preferably 50 to 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 may be at least one of hydrogen peroxide (also known as hydrogen peroxide), sodium peroxide, ammonium persulfate, peracetic acid and the like peroxides, preferably hydrogen peroxide.

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

[0100] In the present invention, the corrosion inhibitor is used for anti-corrosion, and can be specifically 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 carries a large amount of positive charge. When the surface of the corrosion inhibitor carries an electron-donating group, it can better produce electrostatic adsorption with the wafer surface, which is convenient for forming a protective film on the surface, thereby playing 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 and 3,5-diamino-1,2,4-triazole.

[0103] In the present invention, the amino alcohol compound is an amino alcohol compound whose main chain is a straight chain and the number of carbon atoms is ≤8, which can ensure that it contacts the wafer surface more effectively compared with cyclic amino alcohols.

[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, and the like.

[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, the corrosion inhibitor has a mass percentage of 0.025-0.3 wt %, preferably 0.025-0.1 wt %, in the chemical mechanical polishing solution.

[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 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, and 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 a pH value of 3 to 5, more preferably 3 to 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, the polishing accelerator has a mass percentage of 0.2-5 wt %, preferably 0.5-2 wt %.

[0111] In some technical solutions of the present invention, the chemical mechanical polishing liquid may also include additives such as antibacterial agents and / or dispersants. The present invention has no particular restrictions on the types of antibacterial agents and dispersants, which are well known to those skilled in the art.

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

[0113] In some preferred embodiments of the present invention, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, 4-amino-1,2,4-triazole, potassium nitrate, water and a pH adjuster;

[0114] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 4-amino-1,2,4-triazole, sodium nitrate, water and a pH adjuster;

[0115] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, 5-methylbenzotriazole, ammonium nitrate, water and a pH adjuster;

[0116] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, sodium nitrate, water and a pH adjuster;

[0117] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, potassium nitrate, water and a pH adjuster;

[0118] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 3-amino-1,2,4-triazole, ammonium nitrate, water and a pH adjuster;

[0119] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 3-amino-1,2,4-triazole, sodium nitrate, water and a pH adjuster;

[0120] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, potassium nitrate, water and a pH adjuster;

[0121] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, ammonium nitrate, water and a pH adjuster;

[0122] Or, the chemical mechanical polishing liquid comprises silicon dioxide abrasive particles, hydrogen peroxide, L-arginine, ammonium nitrate, water and a pH adjuster;

[0123] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, L-arginine, sodium nitrate, water and a pH adjuster;

[0124] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, L-proline, potassium nitrate, water and a pH adjuster;

[0125] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, L-proline, ammonium nitrate, water and a pH adjuster;

[0126] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, methionine, sodium nitrate, water and a pH adjuster;

[0127] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, methionine, potassium nitrate, water and a pH adjuster;

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

[0129] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, L-serine, sodium nitrate, water and a pH adjuster;

[0130] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, creatine, potassium nitrate, water and a pH adjuster;

[0131] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, creatine, ammonium nitrate, water and a pH adjuster;

[0132] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, tris(hydroxymethyl)methylglycine, sodium nitrate, water and a pH adjuster;

[0133] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, tris(hydroxymethyl)methylglycine, potassium nitrate, water and a pH adjuster;

[0134] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 2-amino-2-methyl-1-propanol, potassium nitrate, water and a pH adjuster;

[0135] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, DL-2-amino-1-butanol, sodium nitrate, water and a pH adjuster;

[0136] Or, the chemical mechanical polishing liquid includes silicon dioxide abrasive particles, hydrogen peroxide, DL-2-amino-1-butanol, potassium nitrate, water and a pH adjuster;

[0137] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 3-amino-4-octanol, ammonium nitrate, water and a pH adjuster;

[0138] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, 3-amino-4-octanol, sodium nitrate, water and a pH adjuster;

[0139] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, methionine, ammonium nitrate, water and a pH adjuster;

[0140] Or, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, 2-aminobenzimidazole, sodium nitrate, water and a pH adjuster;

[0141] Or, the chemical mechanical polishing solution includes silicon dioxide abrasive particles, hydrogen peroxide, methyl-1H-benzotriazole, ammonium nitrate, water and a pH adjuster;

[0142] Or, the chemical mechanical polishing solution comprises modified silicon dioxide abrasive particles, hydrogen peroxide, L-arginine, sodium nitrate, water and a pH adjuster;

[0143] Or, the chemical mechanical polishing solution comprises modified silicon dioxide abrasive particles, hydrogen peroxide, 2-amino-2-methyl-1-propanol, potassium nitrate, water and a pH adjuster;

[0144] Or, the chemical mechanical polishing solution comprises modified silicon dioxide abrasive particles, hydrogen peroxide, 1-hydroxybenzotriazole, ammonium nitrate, water and a pH adjuster;

[0145] Alternatively, the chemical mechanical polishing solution comprises silicon dioxide abrasive particles, hydrogen peroxide, creatine, sodium nitrate, water and a pH adjuster.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0182] 5 wt % of modified silica abrasive 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 4;

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

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

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

[0188] In the formula of the 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 method for preparing a chemical mechanical polishing liquid, which can be prepared by the following method:

[0190] After the abrasive particles, oxidant, corrosion inhibitor, polishing accelerator and water are uniformly mixed, a pH adjuster is used to adjust the pH value to a target value to obtain a chemical mechanical polishing solution.

[0191] Preferably, deionized water and various components except the abrasive particles and the pH adjuster are first added to the container and stirred evenly, and then a certain amount of abrasive particles are added, stirred evenly, and then the pH value is adjusted to the desired pH value with the pH adjuster.

[0192] The 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 polishing disc speed is 50 rpm, the polishing head speed is 60 rpm, the polishing time is 30 min, and the polishing liquid is circulated. The polishing pad is suba 400.

[0193] After testing, it was found that the chemical mechanical polishing liquid can effectively inhibit the corrosion of gallium arsenide wafers and obtain good polishing results. The removal rate of gallium arsenide can reach 10,000 Å / min and above, 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, the polishing liquid provided by the present invention can still maintain a removal rate of more than 80% when the concentration of abrasive particles is reduced from 20% to 1%, and can still meet most process requirements 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 pollutants.

[0194] In summary, the present invention proposes a chemical mechanical polishing liquid suitable for gallium arsenide wafers, which not only achieves a higher polishing rate and good surface roughness, but also has a lower static corrosion rate and low production cost, thereby realizing efficient and stable polishing of gallium arsenide polishing liquid.

[0195] In order to further illustrate the present invention, the following examples are provided 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 liquid of the following comparative examples and embodiments was placed in a 50°C water bath, and the wafer was immersed in the polishing liquid for 30 minutes. The surface condition of the wafer 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 mass of the wafer before and after polishing (m1, m2) using a precision electronic balance:

[0198] MRR = (m1–m2) / (ρ×A×t);

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

[0200] The zeta potential was measured by the zeta potential module of the Nicomp 3000 series nano-laser particle size analyzer, and the particle size of the ground particles was measured by a CPS disc centrifugal nanoparticle 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 in a container and stir continuously. Then take 5 g of 3-aminopropyltrimethoxysilane and dissolve it in an appropriate amount of methanol. Slowly add it to the container and complete it within 30 min. Then continue stirring for 20 min. Take 10 g of the sample, adjust the pH to 4.0, and test the zeta potential. It is found that the zeta potential is 48.6 mV, which is greater than 30 mV, indicating that the modification is successful.

[0203] Embodiments 1 to 41

[0204] The formulas of the chemical mechanical polishing solutions of Examples 1 to 41 are shown in Table 1-1 (Examples 1 to 8) and Table 1-2 (Examples 9 to 41):

[0205] Table 1-1 Table 1-2

[0206] The specific preparation method is as follows:

[0207] After various materials are uniformly mixed with water in proportion, the pH adjuster is adjusted to a suitable pH value, and the polishing liquid is obtained after standing for 30 minutes, during which stirring is uninterrupted.

[0208] Comparative Examples 1~40

[0209] The formulas of the chemical mechanical polishing solutions of Comparative Examples 1 to 40 are shown in Table 2, and the preparation methods are as shown in Examples 1 to 41:

[0210] Table 2

[0211] The corrosion test results and polishing results of the above embodiments and comparative examples are shown in Table 3-1 (Comparative Examples 1 to 25) and Table 3-2 (Comparative Examples 26 to 40 and Examples 1 to 29, Example 32, Example 33, Examples 36 to 38, and Examples 40 to 41):

[0212] Table 3-1 Table 3-2

[0213] From the results of Comparative Examples 1 to 8, it can be seen that after adding 1 wt% hydrogen peroxide, the gallium arsenide wafer will not corrode only under acidic and weakly acidic conditions; under alkaline conditions, the surface and back corrosion generated during the polishing process is difficult to remove by the CMP process, which has a great impact on the subsequent processes, or the wafer may be scrapped due to irreversible corrosion. Figure 1Comparative Example 6 for gallium arsenide polishing, although the back of the crystal is corroded, but the surface roughness is reduced a lot, see 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 oxidant concentration is low and the chemical effect is weak; similarly, adding different concentrations of sodium hypochlorite under alkaline conditions also causes the gallium arsenide wafer to be corroded.

[0214] Before polishing, the surface roughness of GaAs wafers is tens or even hundreds of nanometers, and the flatness is very poor. Figure 3 In comparative example 1, 1 wt% hydrogen peroxide was added. Due to the imbalance between chemical force and mechanical force, the surface of gallium arsenide showed obvious fog after polishing. In addition, after polishing using the above comparative example, the removal rate of gallium arsenide was low and could not meet the demand, and the role of chemical force still needed to be further improved.

[0215] In summary, the following examples still select the acidic polishing solution for screening the corrosion inhibitor in the gallium arsenide polishing.

[0216] Under acidic conditions, after adding a higher concentration of hydrogen peroxide, adding 250-1000 ppm of unbranched triazole compounds thereto (Comparative Examples 17-20) did not inhibit the SER value; similarly, tetrazole, imidazole and pyridazine (six-membered ring) and other types of reagents, even with electron-donating groups such as amino, thiol, etc., could not 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, hydroxyl, etc.) (Examples 1-10), the corrosion of gallium arsenide wafers could be well inhibited, as shown in FIG. Figure 5 .

[0217] 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, etc.), a relatively high SER value will be obtained (Comparative Examples 33-36), and the corrosion effect cannot be inhibited; when the amino acid used has an electron-donating group (such as amino, methyl, hydroxyl, methylthio and hydroxymethyl, etc.), 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 improved, as shown in Figure 6 .

[0218] In the present invention, amino alcohols are used as corrosion inhibitors, and the structure contains an electron-donating amino group, which can significantly reduce the corrosion effect. Whether at low or high concentrations, amino alcohols with shorter main carbon chain structures have the effect of significantly reducing the SER value of GaAs under acidic conditions, so that it can obtain a smoother and mirror-like surface state under polishing conditions. When the carbon chain of such compounds is further lengthened, the corrosion inhibition effect also decreases. Figure 7 .

[0219] The only difference between Example 37 and Example 40 is the type of polishing accelerator. In Example 40, iron nitrate is used as the polishing accelerator, and the removal rate is low and the surface roughness is high, indicating that when the cations in the nitrate are highly oxidizing metal ions, it is not suitable for polishing gallium arsenide.

[0220] Comparative Example 38 does not contain an oxidant and contains 1 wt% polishing accelerator potassium nitrate, and the gallium arsenide removal rate is 4560.7Å / min and the surface roughness is 1.81 nm; Comparative Example 39 contains an oxidant and does not contain a polishing accelerator, and the gallium arsenide removal rate is 2566.7Å / min and the surface roughness is 4.25 nm; Example 24 contains both an oxidant and 1 wt% polishing accelerator potassium nitrate, and the gallium arsenide removal rate is 8330Å / min, which is significantly improved, and the surface roughness is 0.59 nm (see Fig.11 ), and a significant improvement was obtained; thus, it can be seen that the oxidant and the polishing accelerator show a synergistic effect in improving the removal rate of gallium arsenide and the improvement of surface roughness.

[0221] The difference between Example 37 and Example 39 lies in the presence or absence of a polishing accelerator. Relative to Example 39, the gallium arsenide removal rate of Example 37 is increased from 2566.7 Å / min to 6140 Å / min, but the surface roughness is still relatively high, probably because the uniform thickening effect is not achieved.

[0222] The only difference between Comparative Example 37 and Example 24 is the content of polishing accelerator potassium nitrate. In Comparative Example 37, the amount of potassium nitrate added is 0.1 wt%, while in Example 24, the amount of polishing accelerator added is 1 wt%. The gallium arsenide removal rate is increased to 8330Å / min, and the surface roughness is also maintained at a low level.

[0223] Comparative Example 39 contains an oxidant but no polishing accelerator, and the gallium arsenide removal rate is 2566.7 Å / min, and the surface roughness is 4.25 nm; Comparative Example 38 does not contain an oxidant but contains 1 wt% polishing accelerator potassium nitrate, and the gallium arsenide removal rate is 4560.7 Å / min, and the surface roughness is 1.81 nm; Example 24 contains both an oxidant and 1 wt% polishing accelerator potassium nitrate, and the gallium arsenide removal rate is 8330 Å / min, which is significantly improved, and the surface roughness is 0.59 nm, which is significantly improved; it can be seen that the oxidant and the polishing accelerator show a synergistic effect on the improvement of gallium arsenide removal rate and surface roughness.

[0224] In Examples 24 and 40, the SiO2 content was reduced to 1 wt%, but in the presence of an oxidant and a polishing accelerator, a relatively high material removal rate was still maintained; in Examples 29 and 32, when the SiO2 content was increased to 20 wt%, the material removal rate was increased to 11038 Å / min and 11200 Å / min in the presence of an oxidant and a polishing accelerator, and the use of any corrosion inhibitor selected in Examples 1 to 28 had no effect on the removal rate within the concentration range of 0.025 to 0.1 wt%.

[0225] In summary, sodium nitrate, potassium nitrate or ammonium nitrate is added as a polishing accelerator to the polishing liquid containing an oxidant. The two can play a synergistic role, significantly improve the removal rate of gallium arsenide and reduce the surface roughness. The polishing accelerators sodium nitrate, potassium nitrate or ammonium nitrate have a high ion concentration. After being added, the double layer of the abrasive particles is compressed to a certain extent, so that the charge on the surface of the abrasive particles and the charge on the surface of gallium arsenide produce a stronger electrostatic adsorption effect, thereby improving the material removal rate. However, the addition of polishing accelerators to enhance the ionic strength also has a negative impact on the stability of the polishing liquid. When the ionic strength in the polishing liquid is higher, the shielding effect on the electric potential of the particle surface is stronger, resulting in a decrease in the zeta potential of the abrasive particles, thereby reducing the shelf life of the polishing liquid.

[0226] Therefore, the present invention uses 3-aminopropyltrimethoxysilane to modify the silica sol. After the SiO2 abrasive particles in Examples 36, 38, and 40 were modified, the zeta potential was measured to be 46.8 mV at pH 3, which was in a very stable state. The abrasive particles were placed in an oven at 55°C for 28 days, that is, they could be placed at room temperature for about 224 days without further increasing in particle size (see Fig.12), while the polishing performance did not change. However, Example 37 can only be placed at room temperature for about 50 days, indicating that the modified abrasive particles can further extend the shelf life of the polishing liquid without reducing the gallium arsenide removal rate. However, after the present invention uses 3-(2-aminoethylamino)propylmethyldimethoxysilane to modify the silica sol, after adjusting the pH to acidic, the silica sol agglomerates and cannot be used.

[0227] When the polishing liquid provided by the present invention is used to polish gallium arsenide, a removal rate of more than 8000 Å / min and a bright mirror surface can be obtained (the effect is shown in Figure 2 ), low roughness surface state. When the concentration of abrasive particles is further reduced from 20 wt% to 1 wt%, nearly 90% of the cost can be saved, and the removal rate can still be maintained at more than 80%, which can still meet most process requirements on the basis of cost savings.

[0228] 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).

[0229] 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 apparent to those skilled in the art, and the general principles defined herein may 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 the 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, characterized in that: include: Abrasive particles, oxidants, corrosion inhibitors, pH adjusters, polishing accelerators 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.

2. The chemical mechanical polishing solution according to claim 1, characterized in that: 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 to 200 nm; And / or, the oxidant is a peroxide, and the peroxide includes at least one of hydrogen peroxide, sodium peroxide, ammonium persulfate or peracetic acid; And / or, the nitrogen-containing five-membered heterocyclic compound is a triazole compound having an electron-donating group, and the electron-donating group includes any one or more of an amino group, a methyl group or a hydroxyl group; And / or, the amino alcohol compound is an amino alcohol compound with a straight main chain and ≤8 carbon atoms; and / or, the amino acid or amino acid derivative does not contain an electron-withdrawing group, wherein the electron-withdrawing group includes any one or more of a carbonyl group, an acyl group or an ester group; And / or, the pH value of the chemical mechanical polishing solution is 3-5; And / or, the polishing accelerator includes at least one of sodium nitrate, potassium nitrate or ammonium nitrate.

3. The chemical mechanical polishing solution according to claim 2, characterized in that: The zeta potential of the modified silica under acidic conditions is greater than 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 and 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 and 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, and the pH base regulator includes potassium hydroxide and / or sodium hydroxide.

4. The chemical mechanical polishing solution according to claim 3, characterized in that: The modified silica is obtained by modifying silica with a silane reagent, and the zeta potential of the modified silica under acidic conditions is greater than 30 mV; The silane reagent is 3-aminopropyltrimethoxysilane; The mass ratio of the silicon dioxide to the silane reagent is (750-1000):

5.

5. The chemical mechanical polishing solution according to claim 1, characterized in that: The chemical mechanical polishing liquid also includes an auxiliary agent, and the auxiliary agent includes an antibacterial agent and / or a dispersant.

6. The chemical mechanical polishing solution according to claim 1, characterized in that: In terms of mass percentage, the mass percentage of the abrasive particles in the chemical mechanical polishing solution is 0.5-30 wt %; And / or, the mass percentage of the oxidant in the chemical mechanical polishing solution is 0.5-10 wt %; And / or, the mass percentage of the corrosion inhibitor in the chemical mechanical polishing liquid is 0.025-0.3 wt %; And / or, the mass percentage of the polishing accelerator in the chemical mechanical polishing solution is 0.2-5 wt %.

7. The chemical mechanical polishing solution according to claim 1, characterized in that: In terms of mass percentage, the mass percentage of the abrasive particles in the chemical mechanical polishing solution is 0.5-20 wt %; And / or, the mass percentage of the oxidant in the chemical mechanical polishing solution is 3-7 wt %; And / or, the mass percentage of the corrosion inhibitor in the chemical mechanical polishing liquid is 0.025-0.1 wt %; And / or, the mass percentage of the polishing accelerator in the chemical mechanical polishing solution is 0.5-2 wt %.

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

9. A method for preparing a chemical mechanical polishing solution as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: After the abrasive particles, oxidant, corrosion inhibitor, polishing accelerator and water are uniformly mixed, the pH value is adjusted by using a pH adjuster to obtain a chemical mechanical polishing liquid.

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

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