JP2000144109A - Polishing agent slurry for polishing chemical machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polishing agent slurry having a removal selectivity for tungsten to silicon nitride, improved in polishing rate for the tungsten and titanium and excellent in storage stability. SOLUTION: This aqueous polishing agent slurry at pH 1-6 contains (a) 0.1-15 wt.% of abrasive grains having 0.001-1 μm grain diameter, (b) 0.5-15 wt.% of an oxidizing agent, (c) 0.1-10 wt.% of an onium salt obtained by reacting a compound having hydroxyl group and selected from a tetraalkylammonium hydroxide, a tetraarylammonium hydroxide, a tetraalkylphosphonium hydroxide and a tetraarylphosphonium hydroxide with an inorganic acid and (d) an inorganic acid or an organic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slurry for chemical mechanical polishing (CMP) used for polishing a metal film and an insulating film in a single step in the manufacture of integrated circuits and semiconductors.

[0002]

2. Description of the Related Art The reason why chemical mechanical polishing is performed in a semiconductor wafer manufacturing process is that the depth of focus of lithography becomes shallower with the miniaturization of semiconductor devices, and it becomes difficult to secure the yield without planarization by CMP. That is, the CMP process is indispensable in the dual damascene process represented by the Cu wiring.
For example, a semiconductor wafer has a plurality of integrated circuits formed on a silicon or arsenic gallium substrate. Integrated circuits are chemically and physically integrated into a substrate by patterning regions within the substrate and layers on the substrate. The layer is made of various materials having any of conductivity, insulation and semiconductivity. Also, the number of layers for patterning is as many as 3 to 5 layers.

In the process of manufacturing the semiconductor wafer, the surface of the wafer is subjected to chemical mechanical polishing (CMP polishing) in order to remove the insulating layer and expose the metal layer flat on the surface. For example, in the case of chemical mechanical polishing of a wafer having a metal layer of a titanium nitride layer and a tungsten film, an insulating film of silicon dioxide, silicon nitride or the like, and having a wiring of copper, aluminum or the like, usually, alumina, silica, cerium oxide or the like is used. An abrasive slurry having a pH of 1 to 6 containing abrasive grains and an oxidizing agent such as hydrogen peroxide, iron nitrate, ammonium cerium nitrate, acid and pure water is used.

Japanese Patent Application Laid-Open No. Hei 8-197414 discloses that 3% by weight of fumed alumina abrasive grains having a surface area of 40 to 430 m ² / g and an aggregate diameter of less than about 0.4 μm, ferric nitrate
Example 1 proposes a CMP abrasive slurry consisting of 5% by weight and the balance of deionized water. This slurry is excellent at a low pressure, a low platen rotation speed, a metal polishing rate of 3000 ng / min, and a metal layer polishing rate ratio of 110: 1 to the oxide layer polishing rate. However,
Although a very high polishing rate is obtained depending on the polishing conditions as described in paragraph 0029 of the publication,
Low surface quality wafers may be produced.

[0005] Also, Japanese Patent Application Laid-Open No. 10-67986 discloses that
CM consisting of 3% by weight of alumina abrasive grains, 5% by weight of ferric nitrate, 0.01 to 2% by weight of fluorinated substances such as ammonium fluoride, hydrogen fluoride and fluorosilicic acid, and the rest of deionized water
P abrasive slurry is proposed. In this case, the polishing rate of tungsten is improved, but further improvement of the polishing rate is desired. Japanese Patent Laid-Open No. Hei 10-226784 discloses that
9% by weight, 0.2 to 10% by weight of a primary oxidizing agent of hydrogen peroxide, and 0.1% by weight of a secondary oxidizing agent of potassium persulfate or ammonium persulfate.
An aqueous abrasive slurry having a pH of 2 to 8 containing 5 to 10% by weight and 0.5 to 15% by weight of an organic acid is disclosed. This shows a high polishing rate for Ti, TiN and Ai-Cu.

In polishing such a wafer having both an insulating layer and a metal layer, the polishing rate ratio between the two is important from the viewpoint of flattening. Japanese Patent Application Laid-Open No. Hei 10-275858 discloses a method of forming a metal wiring layer and an interlayer insulating film on a substrate and, if necessary, performing a plasma treatment on the surface of the interlayer insulating film to form a silicon nitride protective film having a low polishing rate. Then, an opening is formed in the interlayer insulating film, and a wafer provided with wiring such as a titanium nitride film or a tungsten film on the interlayer insulating film including the opening is polished by chemical mechanical polishing, leaving only the wiring in the opening. Abrasive slurry for CMP polishing used to process
About. It is proposed to provide a plasma oxidation protection layer on the interlayer insulating film layer so that the interlayer insulating film layer is not polished excessively. The polishing rate of the protective layer is 10 with respect to the wiring layer.
We suggest that this is the case. However, it does not disclose the composition of the abrasive slurry.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous abrasive slurry having excellent storage stability and a high polishing rate.

[0008]

According to the present invention, there are provided: (a) 0.1 to 15% by weight of abrasive grains having a particle size of 0.001 μm; (b) 0.5 to 15% by weight of an oxidizing agent; Onium salts obtained by reacting a compound having a hydroxyl group selected from alkylammonium hydroxide, tetraarylammonium hydroxide, tetraalkylphosphonium hydroxide and tetraarylphosphonium hydroxide with an inorganic acid 0.1 to 10 The present invention provides an aqueous abrasive slurry having a pH of 1 to 6 and containing, by weight, and (d) an inorganic acid or an organic acid.

[0009]

The storage stability of the abrasive slurry can be improved by including an onium salt obtained by reacting a tetraalkylammonium hydroxide or a tetraalkylphosphonium hydroxide with an inorganic acid in the abrasive slurry. Was. Particularly, an abrasive slurry using a tetraalkylammonium hydrogen maleate or a tetraalkylammonium hydrogen phthalate as an organic acid has a high polishing rate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Abrasive grains (a): As abrasive grains in the abrasive slurry, silicon dioxide such as colloidal silica and fumed silica;
Examples include aluminum oxide such as mite, alumina, alumina sol, and fumed alumina, cerium oxide, silicon carbide, and chromium oxide. These abrasives have an average particle size of 0.001 to 1.0 μm, preferably 0.02 to 0.
The particles have a size of 5 μm and may have a surface modified by nickel ions, copper ions, or the like. Preferably, colloidal silica, fumed silica, boehmite, and alumina are used.

The solid content of the abrasive grains of the component (a) in the abrasive slurry varies depending on the type and use of the abrasive grains, but is 0.1 to 20% by weight, preferably 0.5 to 10% by weight. %, More preferably 1 to 3% by weight. 0.1% by weight
If it is less than this, a practical polishing rate cannot be obtained. If the content exceeds 20% by weight, no further improvement in the effect can be expected, and it is economically disadvantageous to use many of them.

Oxidizing agent (b): Examples of the oxidizing agent include aqueous hydrogen peroxide, peracetic acid, iron nitrate, potassium iodate, potassium ferricyanide, ammonium cerium nitrate, diethylenetriaminepentaacetate and ethylenediaminetetraacetate. Is mentioned. These differ depending on the target metal. Usually, Ti and W are commercially available 30
% Hydrogen peroxide solution is used, and iron nitrate is used for Cu, but may be used in combination with other oxidizing agents. The oxidizing agent is 0.5 to 15% by weight, preferably 3 to 15% by weight in the abrasive slurry.
8% by weight is used.

Onium salt (c): The onium salt improves the polishing rate and contributes to the storage stability of the abrasive slurry. The onium salt is obtained by reacting a compound having a hydroxyl group selected from tetraalkylammonium hydroxide, tetraarylammonium hydroxide, tetraalkylphosphonium hydroxide and tetraarylphosphonium hydroxide with an inorganic acid. Examples of the inorganic acid as a raw material include hydrofluoric acid, boric acid, sulfuric acid, and phosphoric acid.

The starting material tetraalkylammonium hydroxide includes tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, dimethyldiethylammonium hydroxide, trimethylethylammonium hydroxide, triethylmethylammonium hydroxide, Trimethylbutylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylbutylammonium hydroxide, diethylmethylbutylammonium hydroxide and triethylbenzylammonium hydroxide.

Similarly, the raw material tetraarylammonium hydroxide includes tetraphenylammonium hydroxide, tetranaphthylammonium hydroxide, tetrachlorophenylammonium hydroxide,
Trimethylphenylammonium hydroxide. Similarly, tetraalkylphosphonium hydroxide constituting an onium salt includes tetramethylphosphonium hydroxide, tetraethylphosphonium hydroxide, tetrabutylphosphonium hydroxide, dimethyldiethylphosphonium hydroxide, trimethylethylphosphonium hydroxide, and triethylmethylphosphonium hydroxide. And trimethylbutylphosphonium hydroxide, trimethylbenzylphosphonium hydroxide, trimethylbutylphosphonium hydroxide, diethylmethylbutylphosphonium hydroxide and triethylbenzylphosphonium hydroxide. , Tetranaphthylphosphonium Hydroxide, tetra-chlorophenyl phosphonium hydroxide, and trimethyl phenyl phosphonium hydroxide. The onium salt is used in an amount of 0.1 to 10% by weight in the abrasive slurry. Usually, 0.04 to 5 parts by weight of the abrasive grains (a)
Parts by weight, preferably 0.1 to 2 parts by weight.

Inorganic acid and organic acid (d): The inorganic acid and the organic acid are added to adjust the pH of the slurry to 1 to 6 in order to keep the polishing slurry away from the isoelectric point, It acts to increase the polishing rate by forming an oxide. As such an inorganic acid, a strong acid such as hydrofluoric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, fluorosilicic acid, and hydrochloric acid is preferable from the viewpoint of improving the polishing rate. Also, as the organic acid,
Acetic acid, maleic acid, phthalic acid, citric acid, fumaric acid,
And tetraalkylammonium hydrogen maleate and tetraalkylammonium hydrogen phthalate. Among them, tetramethyl ammonium hydrogen maleate, tetraethyl ammonium hydrogen maleate, triethyl monomethyl ammonium hydrogen maleate, trimethyl monoethyl ammonium hydrogen maleate, tetramethyl ammonium hydrogen phthalate, tetraethyl ammonium hydrogen phthalate
G, triethyl monomethyl ammonium hydrogen maleate,
Tetraalkylammonium hydrogen maleate and tetraalkylammonium hydrogen phthalate, such as trimethylmonoethylammonium hydrogen maleate and diethyldimethylammonium hydrogen phthalate, are preferred in terms of slurry storage stability. The acid is present in the abrasive slurry at 0.0
It is used at a ratio of 5 to 10% by weight, preferably 0.1 to 2% by weight.

Aqueous medium: As a dispersion medium, water alone or water as a main component (70 to 99% by weight in the dispersion medium), and a water-soluble organic solvent such as alcohol or glycol as an auxiliary component (1)
-30% by weight) can be used. The water is preferably pure water or ion-exchanged water which is obtained by filtration with a 0.1 μm cartridge filter and contains as little macroparticles as possible. Alcohols include methyl alcohol,
Ethyl alcohol and isopropyl alcohol include glycols such as ethylene glycol, tetramethylene glycol, diethylene glycol, propylene glycol, and polyethylene glycol. The content of the aqueous dispersion medium in the abrasive slurry is 75 to 9%.
It is 5% by weight, preferably 85-90% by weight. If it is less than 75% by weight, the viscosity of the slurry becomes high and the abrasive slurry becomes
Is poor on the substrate.

Polishing Aid: In addition to the above-mentioned components, a polishing slurry, a rust preventive, a surfactant, a dispersing aid, an antifoaming agent, and the like may be added to the abrasive slurry. As the polishing oil, ethylene glycol, propylene glycol, polyethylene glycol, polyoxyethylene alkyl ether,
And polyoxyethylene alkylphenyl ethers, pronic nonionic surfactants (addition products of ethylene oxide and propylene oxide) and the like. The polishing oil is contained in the abrasive slurry at a ratio of 1 to 10% by weight.

Examples of the surfactant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, a combination of an anionic surfactant and a nonionic surfactant, and an anionic surfactant. Use of a surfactant and an amphoteric surfactant Combination of a cationic surfactant and a nonionic surfactant, and use of a combination of a cationic surfactant and an amphoteric surfactant. The surfactant is contained in the abrasive slurry in an amount of 1 to 3% by weight.

Examples of the anionic surfactant include metal soaps such as sodium palmitate, sodium stearate, calcium oleate, aluminum stearate, and sodium / potassium palmitate; alkyl polyoxyethylene ether carboxylate; Alkyl phenyl polyoxyethylene ether carboxylate, sulfated fatty acid alkyl ester, monoacylglycerol sulfate, secondary alkane sulfonate, N-acyl-N-methyltauric acid, dodecylbenzenesulfonic acid soda, alkyl ether Telluric acid, alkyl polyoxyethylene phosphate, alkyl phenyl polyoxyethylene phosphate,
Sodium naphthalene sulfonate, perfluoroalkyl phosphate, sulfonic acid-modified silicone oil, and the like can be mentioned.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, fatty acid polyoxyethylene ester, fatty acid polyoxyethylene sorbitan ester,
Polyoxyethylene castor oil, fatty acid sucrose ester, polyoxyethylene / oxypropylene alkyl ether and the like can be mentioned. Examples of the amphoteric surfactant include N-alkyl sulfobetaine-modified silicone oil, N-alkyl nitrilotriacetic acid, N-alkyl dimethyl betaine, α-
Trimethylammonio fatty acid, N-alkyl β-aminopropionic acid, N-alkyl β-iminodipropionate, N-alkyloxymethyl-N, N-diethylbetaine, 2-alkylimidazoline derivative, N-alkylsulfobetaine, etc. Is mentioned.

As the dispersing aid, sodium hexametaphosphate
And oleic acid and monobasic calcium phosphate. As the rust inhibitor, alkanolamine / alkanolamine boric acid condensate, monoethanolamine, diethanolamine, triethanolamine, alkanol borate
And nitrogen-containing organic compounds such as ruamine salts and benzisothiazolines. As antifoaming agents, liquid paraffin,
Dimethylsilicone oil, monostearic acid, a mixture of di-glycerides, sorbitan monopalmitiate, and the like. Examples of the inorganic fluoride that improves the polishing rate of Ti include fluorosilicic acid, potassium hydrogen difluoride, ammonium hydrogen difluoride, potassium fluoride, and ammonium fluoride. These are in the abrasive slurry,
0.05 to 1% by weight is blended.

[0023]

The present invention will be described in more detail with reference to the following examples. Example 1 88 parts by weight of water passed through a 0.1 μm cartridge filter, 3 parts by weight of alumina having an average particle size of 0.3 μm, 5 parts by weight of ferric nitrate, 0.5 part by weight of tetramethylammonium hydroxide Parts, triethylmethylammonium hydrogen phthalate 0.2 parts by weight, lauryl alcohol polyoxyethylene ether 1 part by weight, polyethylene glycol (molecular weight 300) 2 parts by weight, ammonium hydrogen difluoride 0.2 part by weight Part of the mixture was mixed with a homogenizer, and further added with hydrofluoric acid to adjust the pH.
An abrasive slurry of 1.4 was prepared. After the abrasive slurry thus obtained was left for 5 hours, a 6000 angstrom thick tungsten and titanium blanket wafer was subjected to chemical mechanical polishing under the following conditions.

Platen rotation speed 45 rpm Wafer (chuck mechanism) rotation speed 45 rpm Abrasive slurry supply amount 100 cc Pressing on wafer 5 psi Tungsten polishing rate is 2600 Å
The polishing rate for titanium and titanium was 1450 angstroms. When a pilot test piece on which a silicon dioxide (SiO ₂ ) film was formed was polished by plasma discharge of tetraethylorthosilicate under the above-mentioned polishing conditions, the polishing rate was 130 Å.

Comparative Example 1 To 89 parts by weight of water passed through a 0.1 μm cartridge filter, 3 parts by weight of alumina having an average particle size of 0.2 μm, 5 parts by weight of ferric nitrate, lauryl alcohol polyoxyethylene ether A mixture of 1 part by weight of ter, 2 parts by weight of polyethylene glycol (molecular weight 300), and 0.2 part by weight of ammonium hydrogen difluoride was mixed with a homogenizer, and an aqueous solution of potassium hydroxide was added to adjust the pH to 1.6.
Abrasive slurry was prepared.

The abrasive slurry thus obtained was used immediately after preparation, and a tungsten and titanium blanket wafer having a thickness of 6000 angstroms and tetraethylorthosilicate were subjected to plasma discharge in silicon dioxide (SiO ₂ ). The pilot test piece on which the film was formed was subjected to chemical mechanical polishing under the same conditions as in Example 1. The polishing rate for tungsten was 2100 Å, the polishing rate for titanium was 1200 Å, and the polishing rate for silicon dioxide (SiO ₂ ) was 140 Å.

EXAMPLE 2 3 parts by weight of alumina having an average particle diameter of 0.3 μm, 5 parts by weight of ferric nitrate, and tetramethylphosphonium hydroxide borate were added to 88 parts by weight of water passed through a 0.1 μm cartridge filter. 0.4 parts by weight, 0.3 parts by weight of tetramethylammonium hydrogen maleate, 1 part by weight of lauryl alcohol polyoxyethylene ether, 2 parts by weight of polyethylene glycol (molecular weight 300), ammonium hydrogen difluoride 0.2 parts by weight of the mixture was mixed with a homogenizer, and hydrofluoric acid was added to adjust the pH to 1.
5 abrasive slurries were prepared.

The abrasive slurry thus obtained is left for 3 hours, and then a 6000 angstrom thick tungsten and titanium blanket wafer and tetraethyl orthosilicate are plasma-discharged to silicon dioxide (SiO _2). ) The pilot test piece on which the film was formed was subjected to chemical mechanical polishing under the same conditions as in Example 1. The polishing rate for tungsten was 2,300 angstroms, the polishing rate for titanium was 1,240 angstroms, and the polishing rate for silicon dioxide (SiO ₂ ) was 110 angstroms.

Example 3 88 parts by weight of water passed through a 0.1 μm cartridge filter, 3 parts by weight of alumina having an average particle diameter of 0.3 μm, 5 parts by weight of cerium nitrate, triethylphenylammonium hydroxide hydrofluoride 0.3 parts by weight, tetramethylammonium hydrogen maleate 0.3
Parts by weight, lauryl alcohol polyoxyethylene ether 1 part by weight, polyethylene glycol (molecular weight 20
0) A mixture of 2 parts by weight and 0.2 parts by weight of ammonium hydrogen difluoride was mixed with a homogenizer, and ammonium water was further added to prepare an abrasive slurry having a pH of 2.0.

After leaving the abrasive slurry thus obtained for 3 hours, a 6000 angstrom thick tungsten and titanium blanket wafer and tetraethylorthosilicate are subjected to plasma discharge to silicon dioxide (SiO _2). ) The pilot test piece on which the film was formed was subjected to chemical mechanical polishing under the same conditions as in Example 1. The polishing rate for tungsten was 2600 Å, the polishing rate for titanium was 1440 Å, and the polishing rate for silicon dioxide (SiO ₂ ) was 120 Å.

Example 4 90 parts by weight of water passed through a 0.1 μm cartridge filter was mixed with colloidal alumina 3 having an average particle size of 0.1 μm.
Parts by weight (solid content), ammonia cerium nitrate
4 parts by weight, dimethyl diethylammonium hydrofluoride 0.4 part by weight, triethylmethylammonium hydrogen phthalate 0.2 part by weight, lauryl alcohol polyoxyethylene ether 1 part by weight, polyethylene glycol (molecular weight) 200) A mixture of 2 parts by weight and 0.2 part by weight of ammonium hydrogen difluoride was homogenized.
And further added ammonium water to adjust the pH to 1.8.
Abrasive slurry was prepared.

After leaving the abrasive slurry thus obtained for 3 hours, a 6000 angstrom thick tungsten and titanium blanket wafer and tetraethylorthosilicate are subjected to plasma discharge to silicon dioxide (SiO _2). ) The pilot test piece on which the film was formed was subjected to chemical mechanical polishing under the same conditions as in Example 1. The polishing rate for tungsten was 2580 angstroms, the polishing rate for titanium was 1360 angstroms, and the polishing rate for silicon dioxide (SiO ₂ ) was 130 angstroms.

[0033]

The abrasive slurry of the present invention has excellent storage stability and, when used as an abrasive slurry for semiconductor device wafers, has an improved selectivity for removing tungsten from silicon dioxide. The polishing rate of titanium is improved.

Claims (10)

[Claims] 1. (a) 0.1 to 15% by weight of abrasive grains having a particle size of 0.001 to 1 μm; (b) 0.5 to 15% by weight of an oxidizing agent; (c) tetraalkylammonium hydroxide; -Ammonium hydroxide, tetraalkylphosphonium hydroxide and tetraali-
PH containing 1 to 10% by weight of an onium salt obtained by reacting a compound having a hydroxyl group selected from ruphosphonium hydroxide with an inorganic acid, and (d) an inorganic acid or an organic acid. Aqueous abrasive slurry. 2. The abrasive slurry according to claim 1, wherein the onium salt is an onium compound selected from a fluoride, a borate, a sulfate and a phosphate. 3. The tetraalkylammonium hydroxide constituting the onium salt is tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, dimethyldiethylammonium hydroxide, trimethylethylammonium hydroxide, triethylmethylammonium hydroxide. 2. The abrasive slurry according to claim 1, wherein the abrasive slurry is a compound selected from the group consisting of trimethylbutylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylbutylammonium hydroxide, diethylmethylbutylammonium hydroxide and triethylbenzylammonium hydroxide. . 4. The tetraarylammonium hydroxide constituting the onium salt is a compound selected from tetraphenylammonium hydroxide, tetranaphthylammonium hydroxide, tetrachlorophenylammonium hydroxide and trimethylphenylammonium hydroxide. Item 4. The abrasive slurry according to Item 1. 5. The tetraalkylphosphonium hydroxide constituting the onium salt is tetramethylphosphonium hydroxide, tetraethylphosphonium hydroxide, tetrabutylphosphonium hydroxide, dimethyldiethylphosphonium hydroxide, trimethylethylphosphonium hydroxide, triethylmethylphosphonium. The abrasive slurry according to claim 1, wherein the abrasive slurry is a compound selected from hydroxide, trimethylbutylphosphonium hydroxide, trimethylbenzylphosphonium hydroxide, trimethylbutylphosphonium hydroxide, diethylmethylbutylphosphonium hydroxide, and triethylbenzylphosphonium hydroxide. -. 6. The tetraarylphosphonium hydroxide constituting the onium salt is a compound selected from tetraphenylphosphonium hydroxide, tetranaphthylphosphonium hydroxide, tetrachlorophenylphosphonium hydroxide, and trimethylphenylphosphonium hydroxide. Item 4. The abrasive slurry according to Item 1. 7. The polishing agent according to claim 1, wherein the oxidizing agent is a compound selected from aqueous hydrogen peroxide, peracetic acid, iron nitrate, potassium ferricyanide, ammonium cerium nitrate, and ethylenediaminetetraacetate. Slurry. 8. The inorganic acid is hydrofluoric acid, sulfuric acid, nitric acid,
The abrasive slurry according to claim 1, which is an inorganic acid selected from phosphoric acid, boric acid and fluorosilicic acid. 9. The organic acid is an organic acid selected from acetic acid, maleic acid, phthalic acid, citric acid, fumaric acid, tetraalkylammonium hydrogen maleate and tetraalkylammonium hydrogen phthalate. Item 4. The abrasive slurry according to Item 1. 10. A tetraalkylammonium hydrogen maleate and a tetraalkylammonium hydrogen phthalate.
Where tetramethylammonium hydrogen maleate, tetraethylammonium hydrogen maleate, triethylmonomethylammonium hydrogen maleate, trimethylmonoethylammonium hydrogen maleate, tetramethylammonium hydrogen phthalate, tetraethylammonium hydrogen phthalate
G, triethyl monomethyl ammonium hydrogen maleate,
The abrasive slurry according to claim 9, which is a compound selected from trimethylmonoethylammonium hydrogen maleate and diethyldimethylammonium hydrogen phthalate.