JPWO2016043088A1 - Abrasive composition for sapphire substrate - Google Patents

Abstract

Disclosed is a sapphire substrate abrasive composition that is free from surface defects such as scratches and that provides a highly polished surface at a high polishing rate. Ingredients contain inorganic abrasive particles, a polishing accelerator and water. The inorganic abrasive particles are alumina particles, the polishing accelerator is an organic carboxylic acid chelating compound, and the pH is 9.0 to 13.0.

Description

  The present invention relates to an abrasive composition, in particular, an abrasive composition for sapphire.

What is generally called a hard and brittle material includes glass, ceramics, stone, semiconductor crystal material, and the like. What is called a hard and brittle material is a material to be polished that is difficult to process, slows the polishing rate, requires a lot of processing time, and requires a high-quality polished surface with high flatness with very few scratches and defects. Has been. A typical example of such a material to be polished is a sapphire substrate.
Sapphire substrates are frequently used in applications such as LED element substrates, and their production volume has increased in recent years. For example, the LED is obtained by growing a GaN film on a sapphire substrate by CVD coating. Sapphire is also used in the cover glass of smartphones and tablets.
As the demand for sapphire substrates increases and the market expands, the need for lower prices and higher quality has increased, and global competition has intensified. Since sapphire is a chemically stable and extremely hard material having a Mohs hardness of 9, processing such as cutting, lapping and polishing is extremely difficult, and processing requires a very long time. Various attempts have been made to reduce the processing time and reduce the cost as much as possible. Conventionally, a sapphire wafer cut from a sapphire ingot is subjected to a lapping process in which diamond abrasive grains harder than sapphire are changed in a multi-stage from large abrasive grains to small abrasive grains, followed by a silica-based abrasive, especially colloidal silica-based A sapphire substrate has been produced by final polishing in a polishing process using an abrasive.
However, in these steps, there is a problem that production cost increases because an expensive abrasive such as diamond is used and processing time becomes long in a plurality of processing steps. Furthermore, because it is a process using a high-hardness diamond abrasive, scratches are likely to enter the surface of the processed substrate, and “latent scratches” that cannot be visually confirmed easily enter the substrate. There is a problem that it is difficult to perform high quality processing. For this reason, it is very difficult to achieve low-cost substrates, cost reduction, and high-quality processing required by the market.

  In polishing sapphire substrates, an abrasive composition for achieving both a high polishing rate and a reduction in scratches and defects and an improvement in flatness is disclosed.

  Patent Document 1 discloses an abrasive for sapphire having a basic pH containing a salt compound in an aqueous medium in which alumina particles, colloidal silica and the like are suspended. The salt compound is an alkali metal or alkaline earth metal salt of an acid, and the acid here is hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid, ascorbic acid, oxalic acid or picoline. There is a description that it is an acid. However, Patent Document 1 does not disclose the use of an organic carboxylic acid chelating compound.

  Patent Document 2 discloses an abrasive composition containing colloidal silica and composite abrasive grains such as aluminum oxide and used for polishing an alumina substrate or the like. However, Patent Document 2 does not disclose the use of an organic carboxylic acid chelating compound.

  Patent Document 3 discloses an abrasive composition used for polishing an aluminum-containing ceramic substrate, which contains an abrasive containing alumina particles and an additive containing a phosphorus compound, and has a pH of about 8 or higher. However, Patent Document 3 does not disclose the use of an organic carboxylic acid chelating compound.

  Patent Document 4 discloses a sapphire polishing slurry containing alumina abrasive grains characterized by having a pH in the range of 10.0 to 14.0. However, Patent Document 4 does not disclose the use of an organic carboxylic acid chelating compound.

In Patent Document 5, as an abrasive composition for hard and brittle materials having a Vickers hardness of 1500 Hv or more, an abrasive composition containing aluminum oxide abrasive grains having a pH of 8.5 or more and a surface area of 20 m ² / g or less. Things are disclosed. However, Patent Document 5 does not disclose the use of an organic carboxylic acid chelating compound.

Special table 2008-531319 gazette JP-A-5-156238 JP 2011-62815 A International Publication No. 2011-136387 International Publication No. 2012/115020

However, in Patent Document 1 in which colloidal silica is used for abrasive grains, a satisfactory polished surface can be obtained, but a sufficient polishing rate cannot be obtained.
In Patent Documents 2 to 5, since alumina, which is relatively hard particles, is used for the abrasive grains, the polishing rate is improved, but it cannot be said that a sufficient polishing rate is obtained. In addition, a highly accurate polished surface is not obtained after polishing.

The present invention has been intensively studied in view of such problems, and is a polishing composition for a sapphire substrate capable of obtaining a highly accurate polished surface with high scratching speed, low scratches, low surface roughness, and the like. Is to provide.
The present invention also provides an abrasive composition that can be used not only for sapphire substrates but also for hard and brittle materials such as hard glass substrates, quartz substrates, silicon and semiconductor substrates having the same problems as described above.

  The present inventor is an abrasive composition for a sapphire substrate containing inorganic abrasive particles, a polishing accelerator, and water, wherein the inorganic abrasive particles are alumina particles, and the polishing accelerator is organic. It discovered that the said subject could be solved by using the abrasive | polishing agent composition for sapphire substrates which is a carboxylic acid type | system | group chelating compound and pH is 9.0-13.0. That is, the present invention relates to the following [1] to [18].

[1] An abrasive composition for a sapphire substrate containing inorganic abrasive particles, a polishing accelerator, and water,
The inorganic abrasive particles are alumina particles;
The polishing accelerator is an organic carboxylic acid chelating compound,
pH is 9.0-13.0,
An abrasive composition for a sapphire substrate, characterized in that.

[2] The organic carboxylic acid chelating compound is ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetetraacetic acid, triethylenetetraaminehexaacetic acid, hydroxyethyliminodiacetic acid, dihydroxyethylglycine, dicarboxymethyl. The abrasive for sapphire substrates according to [1] above, which is at least one selected from the group consisting of glutamic acid and ethylenediamine-N, N ″ -disuccinic acid and sodium, potassium, ammonium and amine salts thereof. Composition.

[3] The polishing composition for a sapphire substrate according to [2], wherein the organic carboxylic acid-based chelating compound is ethylenediaminetetraacetic acid-tetrapotassium salt or hydroxyethylethylenediaminetetraacetic acid-trisodium salt.

[4] Any of [1] to [3], wherein the content of the organic carboxylic acid chelating compound is 0.01 to 5% by mass relative to the mass of the abrasive composition for sapphire substrate. The abrasive | polishing agent composition for sapphire substrates as described in one.

[5] The polishing for sapphire substrate according to [4], wherein the content of the organic carboxylic acid chelating compound is 0.01 to 2% by mass with respect to the mass of the polishing composition for sapphire substrate. Agent composition.

[6] The abrasive composition for a sapphire substrate according to any one of [1] to [5], wherein the alumina particles have a specific surface area of 0.1 to 15 m ² / g.

[7] The abrasive composition for sapphire substrates according to any one of [1] to [6], wherein the alumina particles are α-alumina particles.

[8] The abrasive composition for sapphire substrates according to any one of [1] to [7], wherein the alumina particles have a D50 value of 0.01 to 1.0 μm.

[9] The alumina particles, boehmite Al ₂ O ₃ · H ₂ O and / or pseudoboehmite Al ₂ O ₃ nH ₂ O and (n = 1 to 2) is aluminum oxide as a raw material, the [1] to [8] The abrasive composition for sapphire substrates according to any one of [8].

[10] The sapphire substrate according to any one of [1] to [9], wherein the content of the alumina particles is 5 to 50% by mass with respect to the mass of the abrasive composition for sapphire substrate. Abrasive composition.

[11] The abrasive composition for sapphire substrates according to any one of [1] to [10], further containing a dispersant.

[12] The above-mentioned dispersant is at least one selected from the group consisting of polycarboxylic acids (salts), copolymers containing repeating units of polycarboxylic acids (salts), and condensed phosphates. The abrasive | polishing agent composition for sapphire substrates of description.

[13] The sapphire substrate according to [11] or [12], wherein the content of the dispersant is 0.005 to 0.5 mass% with respect to the mass of the sapphire substrate polishing composition. Abrasive composition.

[14] The composition according to any one of [1] to [13], further including a dispersion aid, wherein the dispersion aid is at least one compound selected from the group consisting of alumina sol and celluloses. An abrasive composition for sapphire substrates.

[15] The abrasive composition for a sapphire substrate according to [14], wherein the alumina sol is at least one selected from the group consisting of a solubilized composition of an aluminum salt and a boehmite sol.

[16] Polishing for sapphire substrate according to [14] or [15], wherein the content of the dispersion aid is 0.01 to 5% by mass relative to the mass of the abrasive composition for sapphire substrate. Agent composition.

[17] A polishing method for a sapphire substrate, comprising polishing using the sapphire substrate abrasive composition according to any one of [1] to [16].

[18] A method for producing a sapphire substrate, comprising a step of polishing using the sapphire substrate abrasive composition according to any one of [1] to [16].

The abrasive composition of the present invention can polish a hard and brittle material such as a sapphire substrate at high speed, and can finish the polished surface to a high quality polished surface with high flatness and few scratches and defects. The abrasive composition of the present invention is particularly suitable for polishing sapphire substrates.
Moreover, the abrasive composition of the present invention can reduce the polishing time and polish a sapphire substrate or the like at a low cost.

  Embodiments of the present invention will be described below. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the invention.

  The abrasive composition for a sapphire substrate of the present invention contains inorganic abrasive particles, a polishing accelerator, and water, the inorganic abrasive particles are alumina particles, and the polishing accelerator is an organic carboxylic acid chelate. The pH of the sapphire substrate polishing composition is 9.0 to 13.0.

[Inorganic abrasive particles]
The abrasive composition of the present invention contains inorganic abrasive particles, and the inorganic abrasive particles are alumina particles. If necessary, silicon oxide, zircon, zirconium oxide, cerium oxide, silicon nitride, silicon carbide, etc. may be added to the inorganic abrasive particles.

In general, as the raw material of the alumina particles, gibbsite _{Al 2 O 3 · 3H 2 O} , boehmite _{Al 2 O 3 · H 2 O} , pseudoboehmite _{Al 2 O 3 · nH 2 O} (n = 1~2), ammonium Examples thereof include aluminum salts such as alum AlNH ₄ (SO ₄ ) ₂ · 12H ₂ O and ammonium dosonite NH ₄ AlCO ₃ (OH) ₂ . These alumina raw materials are prepared, for example, by the following method.
(1) Gibbsite Al ₂ O ₃ 3H ₂ O
It is obtained by dissolving bauxite with a hot solution of sodium hydroxide, removing impurities by filtration, and cooling the resulting solution to dry the resulting precipitate. This method is generally called the buyer method.
(2) Boehmite Al ₂ O ₃ .H ₂ O
It can be obtained by hydrolyzing an aluminum alkoxide Al (OR) ₃ obtained by a reaction between metallic aluminum and alcohol. This method is generally called an aluminum alkoxide method.
(3) Pseudoboehmite Al ₂ O ₃ .nH ₂ O (n = 1 to 2)
It is obtained by treating gibbsite or bayerite with water vapor in an alkaline atmosphere.
(4) Aluminum salt For example, ammonium alum is obtained by cooling an aqueous solution of ammonium sulfate and aluminum sulfate and precipitating from the solution. Ammonium dosonite is obtained by reacting ammonium alum and ammonium carbonate.

  Alumina can be obtained by firing or pyrolyzing these alumina raw materials. Alumina particles can be obtained by pulverizing and classifying the obtained alumina. Alumina particles have various crystal forms such as α-alumina, γ-alumina, δ-alumina, and θ-alumina, and any crystal form can be used.

Raw material of the alumina particles used in the present invention is not particularly limited, boehmite Al ₂ O ₃ · H ₂ O and / or pseudoboehmite _{Al 2 O 3 · nH 2 O} (n = 1~2) was used as a raw material Particularly preferred is alumina.

Compared to alumina particles prepared from other raw materials, alumina particles made from boehmite or pseudo-boehmite can be used to obtain round and polycrystalline alumina particles, which makes it easier to obtain relatively high-purity alumina particles. Further, when preparing the particle size, it is easy to obtain fine particles with few coarse particles, narrow particle size distribution, and few corners.
Since alumina particles having such characteristics are used, when alumina particles made from boehmite or pseudoboehmite are used in the abrasive composition for sapphire substrates of the present invention, scratches on the substrate are reduced and a high polishing rate is obtained. Can do.

The D50 value (median diameter) of the inorganic abrasive particles of the present invention is preferably 0.01 to 1.00 μm. When D50 is smaller than 0.01 μm, it is difficult to obtain a sufficient polishing rate. When D50 is larger than 1.00 μm, surface quality deterioration of the polished surface such as generation of scratches and latent scratches, deterioration of surface roughness, and deterioration of flatness is caused. You may be invited. In addition, when D50 is larger than 1.00 μm, the dispersion stability (how long a dispersed state can be maintained in an aqueous medium without settling of particles) may be deteriorated. D50 is more preferably 0.10 to 0.90 μm, still more preferably 0.20 to 0.70 μm.
D50 can be measured using a laser diffraction particle size distribution analyzer (for example, SALD2200, manufactured by Shimadzu Corporation). D50 is the particle size distribution measured on the basis of volume based on the laser diffraction method. When the measured particle diameters are integrated in order of increasing particle diameter starting from the smallest particle diameter, It is the particle diameter that occupies 50% of the volume of the particles. For example, D50 of 0.45 μm means that the total volume of particles having a particle diameter of 0.45 μm or less occupies 50% of the total volume of all target particles.

The specific surface area of the inorganic abrasive particles of the present invention is preferably from 0.1 to 15 m ² / g. The specific surface area of the alumina abrasive grains gradually becomes a small value by firing or pyrolysis of the alumina raw material, and can be adjusted according to the firing and pyrolysis conditions.
When the specific surface area is smaller than 0.1 m ² / g, the surface roughness increases and scratches may increase. When the specific surface area is larger than 15 m ² / g, it is difficult to obtain a sufficient polishing rate. The specific surface area is more preferably 1 to 14 m ² / g.
The specific surface area can be measured as a BET value using a flow type specific surface area automatic measuring device (for example, Flowsorb II manufactured by Shimadzu Corporation). The BET value is a specific surface area determined by the BET method (gas adsorption method).

The crystal form of the alumina particles of the present invention is preferably α-alumina. When the alumina raw material is fired or pyrolyzed, it undergoes a crystal phase transition to an α crystal, which is a high-temperature stable phase, through crystal phases such as γ crystal, δ crystal, and θ crystal. Since the crystal phase increases in hardness and the size of crystal grains grows as firing and pyrolysis occur, the crystal phase can be adjusted according to the firing and pyrolysis conditions. For example, as described in paragraph 0021 of Japanese Patent No. 4290799, the alumina raw material can be crystallized to α crystal by subjecting the alumina raw material to firing or thermal decomposition at a temperature of 1000 ° C. or higher.
Since α-alumina is a crystal form having sufficient hardness, a high polishing rate can be obtained when α-alumina particles are used in the abrasive composition of the present invention.

  It is preferable that content of the inorganic abrasive particle of this invention is 5-50 mass% with respect to the mass of the abrasive | polishing agent composition for sapphire substrates. If the content is less than 5% by mass, it is difficult to obtain a sufficient polishing rate. Even if the content is more than 50% by mass, no further improvement in the polishing rate is recognized and it is not economical. Dispersibility deteriorates and the viscosity of the abrasive composition increases, so that the polishing rate may decrease, and the liquid feeding resistance may increase when the abrasive composition is circulated and cause problems. is there. The content of the inorganic abrasive particles is more preferably 5 to 20% by mass and further preferably 8 to 15% by mass with respect to the mass of the sapphire substrate abrasive composition.

[pH]
The pH of the abrasive composition of the present invention is 9.0 to 13.0. The above pH is suitable for polishing the sapphire substrate for the following reasons.
Sapphire is single crystal alumina, but it is known that the surface of sapphire acts as a solid acid in water. Therefore, when frictional heat is generated locally during polishing, it is considered that sapphire is alkaline liquid and the surface dissolution reaction is likely to occur due to frictional heat. It is considered that polishing is started by this dissolution reaction. When the pH is less than 9, the dissolution reaction does not start and the polishing rate is remarkably reduced. Even if the value exceeds 13.0, no further improvement in the polishing rate is recognized, and it is dangerous during handling.
The pH is more preferably 10.0 to 13.0.

[Polishing accelerator]
The polishing accelerator accelerates the reaction on the surface of the sapphire substrate at a pH of 9.0 to 13.0 of the polishing composition and provides a high polishing rate.
As the polishing accelerator, an organic carboxylic acid chelating compound is used in the present invention. The abrasive composition of the present invention may optionally use an oxoacid salt as a polishing accelerator.
The polishing accelerator as used in the present invention is considered to have an action of promoting removal of the altered layer due to dissolution generated on the surface of the sapphire substrate by the abrasive composition having a pH of 9.0 to 13.0. Then, an altered layer due to dissolution is generated again by the abrasive composition having a pH of 9.0 to 13.0 on the surface of the sapphire substrate from which the altered layer has been removed, and polishing proceeds by removing the altered layer with a polishing accelerator. It seems to improve the polishing rate.

[Organic carboxylic acid chelating compound]
The organic carboxylic acid chelating compound is a compound having a polydentate ligand that forms a chelate compound with a metal ion, and includes a carboxylic acid or a salt of a carboxylic acid as a ligand. It is.
From the viewpoint of setting the pH of the abrasive composition to 9.0 to 13.0, the organic carboxylic acid chelating compound preferably forms a salt with an alkali metal, ammonia, an amine or the like. These salts can also be produced in the abrasive composition by adding an organic carboxylic acid chelate compound and an alkali metal hydroxide, ammonia or amine, respectively, to the abrasive composition.

Examples of organic carboxylic acid chelating compounds include ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), hydroxyethylethylenediaminetetraacetic acid (HEDTA), triethylenetetraaminehexaacetic acid (TTHA), hydroxy Ethyliminodiacetic acid (HIDA), dihydroxyethylglycine (DHEG), dicarboxymethyl glutamic acid (GMGA), ethylenediamine-N, N ″ -disuccinic acid (EDDS) and their sodium, potassium, ammonium and amine salts Etc. Said compound may be used independently and may be used in combination of 2 or more type. Preferred organic carboxylic acid chelating compounds include ethylenediaminetetraacetic acid-tetrapotassium salt, hydroxyethylethylenediaminetetraacetic acid-trisodium salt, and the like.
Organic carboxylic acid-type chelating compounds are known and can be easily obtained in the market or can be prepared.

  The content of the organic carboxylic acid chelating compound is preferably in the range of 0.01 to 5% by mass with respect to the mass of the sapphire substrate polishing composition. If the amount is less than 0.01% by mass, the effect of promoting the polishing rate is not sufficient, and if the amount exceeds 5% by mass, no further improvement in the polishing rate is recognized and it is not economical, but the dispersibility starts to deteriorate. Sometimes. The content of the organic carboxylic acid chelating compound is more preferably 0.01 to 2% by mass, and still more preferably 0.1 to 1% by mass, with respect to the mass of the sapphire substrate polishing composition. .

[Oxo acid salt]
In the abrasive composition of the present invention, an oxoacid salt may optionally be used in combination as a polishing accelerator.
The oxo acid of the oxo acid salt optionally used in the present invention is preferably an oxo acid of one or more elements selected from the group consisting of aluminum, silicon and boron. These oxo acid salts include aluminates, silicates, aluminosilicates and borates. Among these, use of aluminate is preferable.

  The salt of the oxo acid salt used in the present invention is preferably one or more salts selected from the group consisting of alkali metal salts and alkaline earth metal salts. These oxo acid salts include sodium salts, potassium salts, lithium salts, calcium salts and the like. Of these, the use of sodium salt or potassium salt is preferred.

The oxoacid salt used in the present invention preferably contains sodium aluminate or potassium aluminate, and most preferably contains sodium aluminate.
Oxo acid salts are known and are readily available in the market or can be prepared.

  When the oxo acid salt is used in combination as the polishing accelerator, the content of the oxo acid salt is preferably in the range of 0.01 to 5% by mass relative to the mass of the sapphire substrate polishing composition. If the amount is less than 0.01% by mass, the effect of promoting the polishing rate is not sufficient, and if it exceeds 5% by mass, the dispersibility may begin to deteriorate. The content of the oxoacid salt is more preferably 0.01 to 2% by mass, still more preferably 0.01 to 0.5% by mass, and most preferably 0.00%, based on the mass of the abrasive composition for sapphire substrates. It is in the range of 1 to 0.4% by mass.

  Aggregation of inorganic abrasive particles in the abrasive composition may result in a decrease in polishing surface quality and a decrease in polishing rate such as generation of scratches and deterioration in surface roughness.

[Dispersant]
In the abrasive composition of the present invention, a dispersant may be used in combination for the purpose of improving the dispersion state of the inorganic abrasive particles and improving the above problems.
Examples of the dispersant include a polymer type dispersant, a surfactant type dispersant, an inorganic type dispersant, and the like. In the abrasive composition of the present invention, it is preferable to use a polymer type dispersant and an inorganic type dispersant.
Examples of the polymeric dispersant include polycarboxylic acids (salts), copolymers containing polycarboxylic acid (salt) repeating units, and inorganic dispersants include condensed phosphates.
As polycarboxylic acid (salt), polyacrylic acid, polymethacrylic acid, polyacrylic acid alkali metal salt, polymethacrylic acid alkali metal salt, polyacrylic acid ammonium salt, polymethacrylic acid ammonium salt, polyacrylic acid amine Examples thereof include salts and polymethacrylic acid amine salts.
Examples of the copolymer containing a repeating unit of polycarboxylic acid (salt) include a copolymer of polyacrylic acid and a structural unit containing a sulfonic acid group, a copolymer of polyacrylic acid and a polyacrylate ester, and the like. It is done.
Examples of the condensed phosphate include sodium hexametaphosphate, sodium pyrophosphate, potassium pyrophosphate, sodium tripolyphosphate, sodium acid metaphosphate, and sodium acid pyrophosphate.

  It is preferable that content of a dispersing agent is the range of 0.005-0.5 mass% with respect to the mass of the abrasive | polishing agent composition for sapphire substrates. If it is less than 0.005% by mass, the effect of improving the dispersion state of the inorganic abrasive particles is not sufficient, and if it exceeds 0.5% by mass, the effect of improving the dispersion state of the inorganic abrasive particles reaches its peak and is economical. Not. The content of the dispersant is more preferably 0.01 to 0.5% by mass, still more preferably 0.02 to 0.3% by mass, with respect to the mass of the sapphire substrate abrasive composition. Most preferably, it is 0.05-0.2 mass%.

  When the abrasive composition is allowed to stand in a state where it is contained in a bottle, settling of alumina abrasive grains takes place, and when using the abrasive composition again, it takes time to make it uniformly dispersed again. There is a case. In polishing a sapphire substrate or the like, the abrasive composition is generally supplied in a circulating manner when the abrasive composition is supplied to a polishing machine. In this case, the alumina abrasive grains may settle in the abrasive composition flow path, the abrasive composition tank, or the transport tube, which may cause a reduction in the polishing rate.

[Dispersion aid]
For the purpose of solving the problems such as sedimentation and re-dispersion as described above, a dispersion aid may be used in combination in the abrasive composition of the present invention. Examples of the dispersion aid include alumina sol and celluloses. The reason why the dispersibility of the inorganic abrasive particles is improved by the addition of the dispersion aid is presumed to be because the abrasive particles are trapped in a chemical interaction network such as alumina sol or cellulose.

  Further, the effect of improving the polishing rate by adding a dispersion aid is also recognized.

  The alumina sol is a colloidal dispersion of aluminum hydroxide or hydrated alumina in an aqueous dispersion medium. Examples of the hydrated alumina include boehmite, pseudoboehmite, diaspore, dibsite, and bayerite.

Examples of the alumina sol in which aluminum hydroxide is colloidally dispersed in an aqueous dispersion medium include a sol product of an aluminum salt.
The aluminum salt solation product is obtained by reacting an aluminum salt with a substance that easily reacts with water to generate a hydroxyl group or a compound containing a hydroxyl group.
Examples of the aluminum salt used include aluminum sulfate, aluminum chloride, and aluminum nitrate. Examples of substances that easily react with water and generate hydroxyl groups include ammonia, alkylamines, amine-based chelate compounds, aminocarboxylic acids, aminocarboxylic acid-based chelate compounds, and aminophosphonic acid-based chelate compounds. Examples of the compound containing a hydroxyl group used include sodium hydroxide and potassium hydroxide.

An example of the alumina sol in which hydrated alumina is colloidally dispersed in an aqueous dispersion medium is boehmite sol.
Boehmite sol is obtained by solding boehmite and / or pseudo boehmite with an aluminum salt, an inorganic acid or an organic acid.
Examples of the aluminum salt used include aluminum sulfate, aluminum chloride, and aluminum nitrate. Nitric acid, hydrochloric acid, etc. are mentioned as an inorganic acid used. Examples of the organic acid used include acetic acid and gluconic acid.

  As the boehmite sol, one prepared by the above-mentioned method can be used. However, a solidified boehmite sol that is commercially available can be dissolved in water at the time of use to produce a boehmite sol.

  Examples of celluloses include cellulose, crystalline cellulose, carboxymethylcellulose, hydroxypropylmethylcellulose and the like.

  As the dispersion aid used in the present invention, alumina sol is preferable, and aluminum salt solation product and boehmite sol are more preferable.

  The content of the dispersion aid is preferably 0.01 to 5% by mass with respect to the mass of the sapphire substrate abrasive composition. When the amount is less than 0.01% by mass, the dispersion effect of the inorganic abrasive particles cannot be sufficiently obtained. When the amount is more than 5% by mass, an increase in the viscosity of the abrasive composition is observed, which hinders circulation use. Further, when the content of the dispersion aid is more than 5% by mass, the polishing rate may be lowered. The content of the dispersion aid is more preferably 0.01 to 2% by mass with respect to the mass of the abrasive composition for sapphire substrate.

[Other]
The abrasive composition of the present invention may contain a pH adjusting agent in order to obtain a predetermined pH. Examples of the pH adjuster include inorganic bases, organic bases, inorganic acids, organic acids and the like. Examples of the inorganic base include sodium hydroxide, potassium hydroxide, ammonia and the like. Examples of the organic base include tetramethylammonium hydroxide and alkanolamine. Examples of the inorganic acid include sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid and the like. Examples of the organic acid include citric acid and malic acid.

  The abrasive composition of the present invention includes a rust inhibitor, antibacterial agent, cleaning agent, surface modifier, scratch reducing agent, viscosity modifier, antifoaming agent, antioxidant, surfactant for other purposes, etc. Can also be used together as necessary.

  The abrasive composition of the present invention can be prepared by mixing each component.

  The abrasive composition of the present invention is an electronic component material such as an LED element, an optical component such as an optical filter, an electrically insulating material, a watch cover or window material, a sapphire substrate used as an abrasion resistant material, a glass substrate, It can be used for polishing a quartz substrate, silicon, a semiconductor substrate, or the like.

  Examples and Comparative Examples will be described in detail below, but the present invention is not limited to these Examples.

(1) Preparation method of abrasive | polishing agent composition The alumina particle used by an Example and a comparative example was prepared with the following method.
(Preparation example of alumina particles 1)
Commercially available boehmite alumina (CA alumina manufactured by Sasol Corporation) was fired at 1160 ° C. for 9 hours so as to have a specific surface area BET of ⁴ m ² / g. The crystal form of the alumina after firing was α-alumina. The fired product was wet pulverized and adjusted to D50 of 0.35 μm, 0.45 μm, and 0.70 μm. The specific surface area of the prepared alumina particles was as shown in the table.
(Example of preparation of alumina particles 2)
Commercially available alumina (APA-0.4AF manufactured by Sasol Co., Ltd.) having a crystal form of α-alumina using boehmite alumina as a raw material was wet pulverized to adjust D50 to 0.35 μm. The specific surface area of the prepared alumina particles was BET 11 m ² / g.

D50 of the alumina particles was measured using a laser diffraction particle size distribution measuring machine (SALD2200, manufactured by Shimadzu Corporation). The particle size distribution of the alumina particles is based on volume.
The specific surface area of the alumina particles was measured using a flow type specific surface area automatic measuring device (Shimadzu Corporation, Flowsorb II).

Alumina sol as a dispersion aid used in Examples and Comparative Examples was prepared by the following method.
(Preparation example of alumina sol 1)
77 g of commercially available boehmite alumina (CA alumina manufactured by Sasol Corporation), 44 g of aluminum chloride and 879 g of water were mixed and stirred with a homomixer to prepare a sol.
(Preparation example of alumina sol 2)
107 g of 25% aqueous ammonia was added to an aqueous aluminum sulfate solution in which 179 g of aluminum sulfate was dissolved in 714 g of water, and the mixture was mixed and stirred with a homomixer to prepare a sol.
(Preparation example of alumina sol 3)
100 g of commercially available boehmite sol (Dispal 23N4-80, manufactured by Sasol) was added to 888 g of water, and the mixture was well mixed and stirred to prepare a sol.

Alumina particles prepared by the above method as alumina abrasive grains, tetradiamine salt of ethylenediaminetetraacetic acid (EDTA-4K), trisodium salt of hydroxyethylethylenediaminetetraacetic acid (HEDTA-3Na) and sodium aluminate as polishing accelerators, An abrasive composition was prepared by the following method using sodium hexametaphosphate as a dispersant and alumina sol prepared by the above method as a dispersion aid.
Example 1
Alumina particles 1 (D50: 0.45 μm, BET 10 m ² / g), ethylenediaminetetraacetic acid tetrapotassium salt (EDTA-4K) and water were stirred and mixed so as to have the ratios in Table 1 to obtain an abrasive composition. Was prepared. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.
(Example 2)
Alumina particles 1 (D50: 0.45 μm, BET 10 m ² / g), ethylenediaminetetraacetic acid tetrapotassium salt (EDTA-4K), sodium hexametaphosphate (hexameta), alumina sol 1 and water so as to have the ratio in Table 1. The mixture was stirred and mixed to prepare an abrasive composition. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.
(Example 3)
Stir and mix alumina particles 1 (D50: 0.45 μm, BET 10 m ² / g), tetrapotassium salt of ethylenediaminetetraacetic acid (EDTA-4K), sodium hexametaphosphate (hexameta) and water in the proportions shown in Table 1. Thus, an abrasive composition was prepared. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.
Example 4
Alumina particles 1 (D50: 0.45 μm, BET 10 m ² / g), ethylenediaminetetraacetic acid tetrapotassium salt (EDTA-4K), alumina sol 1 and water were stirred and mixed so as to have the ratios in Table 1 and polished. An agent composition was prepared. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.
(Example 5)
Ratio of alumina particles 1 (D50: 0.45 μm, BET 10 m ² / g), tetrapotassium salt of ethylenediaminetetraacetic acid (EDTA-4K), sodium aluminate, sodium hexametaphosphate (hexameta), alumina sol 1 and water in Table 1 Then, the mixture was stirred and mixed to prepare an abrasive composition. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.
(Example 6)
Alumina particles 1 (D50: 0.45 μm, BET 10 m ² / g), hydroxyethylethylenediaminetetraacetic acid trisodium salt (HEDTA-3Na), sodium hexametaphosphate (hexameta), alumina sol 2 and water are in the proportions in the table. The mixture was stirred and mixed to prepare an abrasive composition, and tetramethylammonium hydroxide (TMAH) was further added to adjust the pH in Table 1. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.
(Example 7)
The abrasive composition was prepared in the same manner as in Example 2 except that alumina particles 1 (D50: 0.35 μm, BET 13 m ² / g) were used as alumina abrasive grains, and the concentration of EDTA-4K was 0.6 mass%. Prepared. A polishing test was conducted using the obtained abrasive composition.
(Example 8)
The abrasive composition was prepared in the same manner as in Example 2 except that alumina particles 1 (D50: 0.70 μm, BET 8 m ² / g) were used as alumina abrasive grains and the concentration of EDTA-4K was 0.6 mass%. Prepared. A polishing test was conducted using the obtained abrasive composition.
Example 9
Stir and mix alumina particles 2 (D50: 0.35 μm, BET 11 m ² / g), tetrapotassium salt of ethylenediaminetetraacetic acid (EDTA-4K), sodium aluminate, alumina sol 3 and water so as to have the ratios in Table 1. Thus, an abrasive composition was prepared. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.
(Comparative Example 1)
Alumina particles 1 (D50: 0.45 μm, BET 10 m ² / g) and water were stirred and mixed so as to have the ratios shown in the table to prepare an abrasive composition, and sodium hydroxide was further added thereto. Adjusted to medium pH. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.
(Comparative Example 2)
Alumina particles 1 (D50: 0.45 μm, BET 10 m ² / g), sodium hexametaphosphate (hexameta), alumina sol 1 and water were stirred and mixed so as to have the ratio in the table to prepare an abrasive composition, Further, sodium hydroxide was added to adjust the pH in Table 1. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.
(Comparative Example 3)
Alumina particles 1 (D50: 0.45 μm, BET 10 m ² / g), organic sulfonic acid-based chelating compound hydroxyethylidene diphosphonic acid (HEDP), sodium hexametaphosphate (hexameta), alumina sol 1 and water in the ratio The mixture was stirred and mixed to prepare an abrasive composition, and sodium hydroxide was further added to adjust the pH in Table 1. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.
(Comparative Example 4)
An abrasive composition was prepared in the same manner as in Comparative Example 2 except that alumina particles 1 (D50: 0.35 μm, BET 13 m ² / g) were used as alumina abrasive grains. A polishing test was conducted using the obtained abrasive composition.
(Comparative Example 5)
An abrasive composition was prepared in the same manner as in Comparative Example 2 except that alumina particles 1 (D50: 0.70 μm, BET 8 m ² / g) were used as alumina abrasive grains. A polishing test was conducted using the obtained abrasive composition.
(Comparative Example 6)
Alumina particles 2 (D50: 0.35 μm, BET 11 m ² / g), alumina sol 3 and water are stirred and mixed so as to have the ratio in the table to prepare an abrasive composition, and sodium hydroxide is further added. The pH in Table 1 was adjusted. In addition, water was added so that it might become the remainder which remove | excluded the other component from the composition. A polishing test was conducted using the obtained abrasive composition.

The description of the chelating compound in the table refers to the following.
EDTA-4K: ethylenediaminetetraacetic acid-tetrapotassium salt HEDTA-3Na: hydroxyethylethylenediaminetetraacetic acid-trisodium salt HEDP: hydroxyethylidene diphosphonic acid

The description of the oxo acid salt in the table indicates the following.
Na aluminate: Sodium aluminate

The description of the dispersant in the table refers to the following.
Hexmeta: sodium hexametaphosphate

The description of the pH adjuster in the table refers to the following.
TMAH: Tetramethylammonium hydroxide NaOH: Sodium hydroxide

  Using the resulting abrasive composition, a sapphire substrate was polished under the following polishing conditions.

(2) Polishing conditions Polishing machine: Speedfam air pressure 6B double-side polishing machine Polishing pad: SUBA-800 (manufactured by Nitta Haas)
Surface plate rotation speed: Lower 60rpm, Upper 20rpm
Load: 120 g / cm ²
Polishing time: 420 minutes (7 hours)
Abrasive composition supply amount: 120 ml / min Circulating polishing work: φ7.62 cm (3 inch) sapphire wafer × 3P

(3) Evaluation of polished substrate The polished substrate was evaluated by washing and drying the sapphire substrate polished by the above method, and then using the following measuring method and measuring machine.

(3-1) Polishing rate Polishing rate [μm / hr] = (mass before polishing of sapphire substrate−mass after polishing) [g] ÷ polishing area of sapphire substrate [45 cm ² ] ÷ density of sapphire substrate [3.98 g / Cm ³ ] ÷ polishing time [420 minutes] × 10000 [μm / cm] × 60 [minute / hr], and shown in the table.

(3-2) Surface roughness Ra
The surface roughness Ra of the sapphire substrate was measured with an atomic force microscope AFM (SPA-500 type manufactured by SII Technology) in a non-contact mode, a scan rate of 1.0 Hz, and a visual field of 10 μm ² .

(3-3) Scratches The sapphire substrate was observed with MICRO-MAX (VMX-2200Z-PL) manufactured by Tanaka Kikai Co., Ltd., and the number of scratches was counted.
When the total number of scratches on both sides is 2 or less, evaluation 1 is evaluated, 3 is evaluated 2, evaluation 4 is evaluated 3, evaluation 5 to 8 is evaluation 4, evaluation 9 or more is evaluation 5.

(4) Evaluation of redispersibility of slurry About the redispersibility of a slurry, the prepared abrasive | polishing agent composition was evaluated by the following method.
Put 1kg of the abrasive composition into a 1L container, let it stand day and night, turn the container upside down, shake it 20 times, and settling solids in the slurry will not remain on the bottom. Even a small amount was left as “settling residue”.

When Example 1 and Comparative Example 1, Examples 2 and 6 and Comparative Example 2, Example 7 and Comparative Example 4, and Example 8 and Comparative Example 5 are compared, an organic carboxylic acid chelating compound is used as a polishing accelerator. It can be seen that a high polishing rate can be obtained by adding.
When Examples 2, 3, 4 and Example 1 are compared, it can be seen that the redispersibility of the slurry is improved when at least one of the dispersant and the dispersion aid is included.

The present invention is an electronic component material such as an LED element, an optical component such as an optical filter, an electrically insulating material, a watch cover or window material, a sapphire substrate used as a wear resistant material, a glass substrate, a quartz substrate, silicon, The present invention relates to an abrasive composition used for polishing a semiconductor substrate or the like. The present invention is not limited to these applications, and can be used as an abrasive composition for other hard and brittle materials.
In particular, the abrasive composition of the present invention is a heat-resistant chip for laser emission, a substrate for LED lighting, a material for electronic components such as a substrate for high-frequency power devices used as GaN on Sapphire, a polarizer holding plate for a liquid crystal projector, a camera, etc. Translucent optical parts used in slabs, electrical insulation materials, heat-resistant furnace window materials, sapphire tubes (thermocouple protective tubes), sapphire glass, high-end smart phone (multifunction mobile phone) cover glasses, camera Used for polishing sapphire substrates, which are used and studied for protective lenses, touch ID sensors, tablets (small plate-like portable information communication devices), cover glasses (screens) for car navigation, touch ID sensors, etc. Is suitable.

Claims (18)

A polishing composition for a sapphire substrate, comprising inorganic abrasive particles, a polishing accelerator, and water,
The inorganic abrasive particles are alumina particles;
The polishing accelerator is an organic carboxylic acid chelating compound,
pH is 9.0-13.0,
An abrasive composition for a sapphire substrate, characterized in that.   The organic carboxylic acid chelating compound is ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetetraacetic acid, triethylenetetraaminehexaacetic acid, hydroxyethyliminodiacetic acid, dihydroxyethylglycine, dicarboxymethylglutamic acid and ethylenediamine. The abrasive | polishing agent composition for sapphire substrates of Claim 1 which is 1 or more types selected from the group which consists of -N, N ''-disuccinic acid and those sodium salt, potassium salt, ammonium salt, and amine salt.   The abrasive | polishing agent composition for sapphire substrates of Claim 2 whose said organic carboxylic acid type chelating compound is ethylenediaminetetraacetic acid-tetrapotassium salt or hydroxyethylethylenediaminetetraacetic acid-trisodium salt.   Sapphire according to any one of claims 1 to 3, wherein the content of the organic carboxylic acid chelating compound is 0.01 to 5% by mass with respect to the mass of the abrasive composition for sapphire substrate. Abrasive composition for substrates.   The abrasive composition for sapphire substrates according to claim 4, wherein the content of the organic carboxylic acid chelating compound is 0.01 to 2% by mass with respect to the mass of the abrasive composition for sapphire substrates. The abrasive | polishing agent composition for sapphire substrates of any one of Claims 1-5 whose specific surface area of the said alumina particle is 0.1-15 m < ² > / g.   The abrasive | polishing agent composition for sapphire substrates of any one of Claims 1-6 whose said alumina particle is alpha alumina particle.   The abrasive | polishing agent composition for sapphire substrates of any one of Claims 1-7 whose D50 value of the said alumina particle is 0.01-1.0 micrometer. The alumina particles, boehmite Al ₂ O ₃ · H ₂ O and / or pseudoboehmite Al ₂ O ₃ nH ₂ O and (n = 1 to 2) is aluminum oxide as a raw material, any one of claims 1 to 8 The abrasive | polishing agent composition for sapphire substrates of 1 item | term.   The abrasive composition for sapphire substrates according to any one of claims 1 to 9, wherein the content of the alumina particles is 5 to 50 mass% with respect to the mass of the abrasive composition for sapphire substrates.   Furthermore, the abrasive | polishing agent composition for sapphire substrates of any one of Claims 1-10 containing a dispersing agent.   The sapphire according to claim 11, wherein the dispersant is at least one selected from the group consisting of a polycarboxylic acid (salt), a copolymer containing repeating units of polycarboxylic acid (salt), and a condensed phosphate. Abrasive composition for substrates.   The abrasive composition for sapphire substrates according to claim 11 or 12, wherein the content of the dispersant is 0.005 to 0.5 mass% with respect to the mass of the abrasive composition for sapphire substrates.   The abrasive for sapphire substrates according to any one of claims 1 to 13, further comprising a dispersion aid, wherein the dispersion aid is at least one compound selected from the group consisting of alumina sol and celluloses. Composition.   The abrasive | polishing agent composition for sapphire substrates of Claim 14 whose said alumina sol is 1 or more types selected from the group which consists of a sol-ized composition of aluminum salt, and boehmite sol.   The abrasive composition for sapphire substrates according to claim 14 or 15, wherein the content of the dispersion aid is 0.01 to 5 mass% with respect to the mass of the abrasive composition for sapphire substrates.   Polishing using the abrasive | polishing agent composition for sapphire substrates of any one of Claims 1-16, The polishing method of a sapphire substrate characterized by the above-mentioned.   The manufacturing method of a sapphire substrate including the process of grind | polishing using the abrasive | polishing agent composition for sapphire substrates of any one of Claims 1-16.