JP6425992B2 - Polishing liquid composition for sapphire plate - Google Patents

Description

  The present invention relates to a polishing composition for a sapphire plate, a method of manufacturing a sapphire plate using the same, and a method of polishing a sapphire plate to be polished.

  Hard and brittle materials such as sapphire are indispensable as optical materials, electronic materials or mechanical materials.

  For example, artificial sapphire plates are used as materials for various applications such as integrated circuit substrates, lenses for infrared detection, clocks, and portable terminal devices such as smartphones. In particular, with the rapid spread of LEDs, the demand for sapphire plates used as the substrate thereof is rapidly increasing. It is desirable that the sapphire substrate for an LED has high surface smoothness in order to improve the light emission efficiency of the LED element.

  In order to satisfy the surface smoothness of the sapphire plate, finish polishing using a polishing composition containing silica particles is performed. The use of silica (Mohs hardness 7) particles having a hardness lower than that of a sapphire (.alpha.-alumina, Mohs hardness 9) plate as abrasive grains prevents pits and scratches from being generated on the surface of the sapphire plate. However, although sapphire is excellent in mechanical, chemical and thermal stability, it has a problem that the polishing rate is low in finish polishing using silica particles.

  For the problem of polishing rate, for example, Patent Document 1 discloses a polishing composition for a sapphire plate containing a salt compound having a basic pH such as sodium chloride or potassium chloride and dissolved. Patent Documents 2 and 3 disclose abrasive liquid compositions in which alumina particles are used as abrasive grains for the purpose of improving the polishing rate, and which contain an additive such as a phosphorus compound. Patent Document 4 discloses a polishing composition capable of improving the polishing rate by containing a phosphoric acid or phosphonic acid-based compound and having a pH in an acidic region. Patent Document 5 discloses that two or more types of abrasive particles are used for the purpose of suppressing a reduction in polishing rate associated with repeated use. Patent Document 6 discloses a water-based processed polishing liquid which is a stainless steel to be polished, uses a diamond abrasive as polishing particles, and contains a phosphate and an alkylene glycol. Patent Document 7 discloses a polishing composition for a sapphire substrate containing at least one of an alkanolamine and a fluorine compound having a perfluoroalkyl group for the purpose of improving the polishing rate. Patent Document 8 discloses a polishing composition containing a surface adsorbent such as a vinyl polymer and a polyalkylene oxide for the purpose of reducing surface defects (orange peel) of an object to be polished such as aluminum oxide.

Japanese Patent Application Publication No. 2008-531319 Japanese Patent Application Publication No. 2006-524583 JP, 2011-62815, A Japanese Patent Application Publication No. 2009-538236 WO 13/099595 JP 2004-331686 A JP, 2009-297818, A JP, 2014-641, A

  On the other hand, at the same time as further improving the polishing rate of the sapphire plate for the purpose of improving the productivity, it is desired to secure good surface smoothness.

  The present invention provides a polishing composition for a sapphire plate capable of achieving both high-speed polishing and low surface roughness, a method of manufacturing a sapphire plate using the same, and a method of polishing a sapphire plate to be polished.

The polishing composition for a sapphire plate of the present disclosure contains the following components A to C, and the pH at 25 ° C. is 8 or more.
Component A: Silica particle component B: Inorganic phosphate component C: alkanolamine, fluorine-based compound having a perfluoroalkyl group, water-soluble vinyl-based polymer, and water-soluble polymer compound containing a polyalkylene oxide skeleton 1 More than a class of additives

  One example of a method of manufacturing a sapphire plate of the present disclosure includes the steps of supplying the polishing liquid composition for sapphire plate of the present invention to a polishing sapphire plate and polishing the sapphire plate. It is a method.

  The method for polishing a sapphire plate to be polished according to the present invention includes the step of supplying the polishing liquid composition for a sapphire plate according to the present invention to the sapphire plate to be polished and polishing the sapphire plate to be polished Polishing method.

  According to the present invention, it is possible to provide a polishing composition for a sapphire plate capable of achieving both high-speed polishing and low surface roughness, a method of manufacturing a sapphire plate using the same, and a method of polishing a sapphire plate to be polished.

  The present invention relates to an inorganic phosphate (component B), an alkanolamine and a peroxy amine when the polishing composition containing silica particles (component A) and an aqueous medium (component D) has a pH of 8 or more. High-speed polishing and low surface roughness by including at least one additive (component C) selected from fluorine-based compounds having a fluoroalkyl group, water-soluble vinyl-based polymers, and polymers containing a polyalkylene oxide skeleton Based on the knowledge that both

  The polishing composition for a sapphire plate of the present invention (hereinafter sometimes abbreviated as "polishing composition") may be a silica particle (component A), an inorganic phosphate (component B), an alkanolamine, a perfluoroalkyl And at least one additive (component C) selected from a fluorine-based compound having a group, a water-soluble vinyl-based polymer, and a water-soluble polymer compound containing a polyalkylene oxide skeleton, and an aqueous medium (component D). It is not clear why it is possible to achieve both high speed polishing and low surface roughness by including the inorganic phosphate (component B) and the additive (component C) in the polishing composition of the present invention. It is guessed that.

  When an alkaline polishing composition is supplied to the surface of the sapphire substrate to be polished, alkali hydrolysis of sapphire softens the crystal structure of the surface of the sapphire substrate to be polished. When the surface of the softened sapphire substrate is polished, high-speed polishing and reduction of the surface roughness can be performed as compared to the case where the surface of the unrefined sapphire plate is not polished. When an inorganic phosphate is contained in a polishing composition containing silica particles and an aqueous medium and having a pH of 8 or more at 25 ° C., sapphire reacts with the inorganic phosphate to produce aluminum phosphate. . With the formation of aluminum phosphate, an alkali is generated as a by-product, and the alkali softens the crystal structure to a deeper portion of the sapphire plate to be polished, and additionally, the additive (component C) is as follows: By contributing to the reduction of the surface roughness and / or the improvement of the polishing rate, it is presumed that both high speed polishing and low surface roughness can be achieved.

  Among the additives (component C), alkanolamines capture sapphire polishing debris, improve the removal rate of sapphire polishing debris from the polished sapphire plate and contribute to the improvement of the dispersibility of silica particles. It is presumed that this contributes to the reduction of the surface roughness and the improvement of the polishing rate. The fluorine compound having a perfluoroalkyl group reduces the frictional resistance between the sapphire plate to be polished and the polishing pad, and improves the circulation of the silica particles between the sapphire plate to be polished and the polishing pad, thereby making the surface rough. It is presumed that it contributes to the reduction of the thickness and the improvement of the polishing rate. It is presumed that a water-soluble polymer containing a water-soluble vinyl polymer or a polyalkylene oxide skeleton contributes to the reduction of the surface roughness by adsorbing to the surface of the silica particles and the sapphire plate to be polished. However, the present invention is not limited to these estimations.

<Silica particles (component A)>
The silica particles (component A) contained in the polishing composition of the present invention act as abrasive grains. As these silica particles, colloidal silica, fumed silica and the like can be mentioned, but from the viewpoint of improving the smoothness of the object to be polished, colloidal silica is more preferable.

  The use of the silica particles is preferably in the form of a slurry from the viewpoint of operability. When the silica particles contained in the polishing composition of the present invention are colloidal silica, the colloidal silica may be obtained from a hydrolyzate of water glass or alkoxysilane from the viewpoint of easiness of production and economy. Preferably, it is more preferably obtained from water glass. Silica particles obtained from water glass can be produced by a conventionally known method.

The silica particles may be silica particles whose surface is surface-treated with a silane coupling agent or the like, but from the viewpoint of improving the polishing rate, silica particles which are not surface-treated are preferable. The silica particles may contain an inorganic element other than Si such as Al or Zr, but from the viewpoint of improving the polishing rate, the main component of the solid content is preferably SiO ₂ , in terms of anhydrous oxide The SiO ₂ content is preferably 90% by mass or more, more preferably 95% by mass or more, and still more preferably 99% by mass or more.

The content of the silica particles in the polishing composition of the present invention is preferably 1% by mass or more, more preferably 5% by mass or more, and 10% by mass or more in terms of SiO ₂ conversion concentration from the viewpoint of improving the polishing rate. More preferable. In addition, the content of the silica particles in the polishing composition of the present invention is preferably 40% by mass or less in terms of SiO ₂ concentration, from the viewpoint of cost reduction of the polishing composition and improvement of storage stability. % Or less is more preferable, and 25 mass% or less is more preferable.

  The average secondary particle size (average particle size) measured by the dynamic light scattering method of the silica particles is preferably 10 nm or more, more preferably 50 nm or more, still more preferably 80 nm or more, from the viewpoint of improving the polishing rate. From the viewpoint of improving the smoothness of the object to be polished, the thickness is preferably 500 nm or less, more preferably 300 nm or less, and still more preferably 200 nm or less. In addition, the average secondary particle size measured by the dynamic light scattering method of the said silica particle can be calculated | required by the method as described in the Example mentioned later.

The BET specific surface area of the silica particles in the polishing composition of the present invention is preferably 10 m ² / g or more, more preferably 20 m ² / g or more, still more preferably 30 m ² / g or more, from the viewpoint of improving the polishing rate. From the same viewpoint, 200 m ² / g or less is preferable, 100 m ² / g or less is more preferable, and 60 m ² / g or less is more preferable.

  The average primary particle diameter of the silica particles is preferably 500 nm or less, more preferably 300 nm or less, still more preferably 200 nm or less, still more preferably 150 nm or less, from the viewpoint of improving the smoothness of the polished sapphire plate surface. From the viewpoint of securing a high polishing rate, 45 nm or more is preferable, and 70 nm or more is more preferable. In addition, the average primary particle diameter of the said silica particle is a number average of the particle diameter calculated | required as a circle equivalent diameter in an electron microscope (TEM) observation image, as described in the Example mentioned later.

The following coefficient of variation of the average primary particle diameter of the silica particles in the polishing composition of the present invention is preferably 1% to 50%, and is 1% to 30% from the viewpoint of improving the polishing rate. And more preferably 1% to 10%.
Coefficient of variation = (standard deviation / average primary particle size)

  The particle shape of the silica particles (component A) contained in the polishing liquid composition of the present invention may be any shape such as spherical, gold palm sugar type, association type etc., but spherical or gold palm sugar type Preferably, spherical shape is more preferable from the viewpoint of coexistence with surface roughness reduction.

<Inorganic phosphate (component B)>
The polishing composition of the present invention contains an inorganic phosphate (component B) from the viewpoint of achieving both high-speed polishing and low surface roughness. As the inorganic phosphate, one or more inorganic phosphates selected from the group consisting of orthophosphates, phosphites, and hypophosphites from the viewpoint of achieving both high-speed polishing and low surface roughness Preferably, orthophosphate and phosphite are more preferable. The inorganic phosphate is preferably at least one selected from the group consisting of alkali metal salts, alkaline earth metal salts and ammonium salts. As the alkali metal or alkaline earth metal, magnesium, calcium, sodium and potassium are preferable. Among these, from the viewpoint of aggregation suppression of silica particles, the inorganic phosphate is more preferably at least one selected from sodium salt, potassium salt and ammonium salt.

Specific examples of the inorganic phosphate (component B) include sodium phosphate (Na ₃ PO ₄ ), potassium phosphate (K ₃ PO ₄ ), and phosphoric acid monobasic from the viewpoint of achieving both high-speed polishing and low surface roughness. Disodium hydrogen (Na ₂ HPO ₄ ), monosodium dihydrogen phosphate (NaH ₂ PO ₄ ), monopotassium dihydrogen phosphate (KH ₂ PO ₄ ), monoammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ) , Orthophosphates such as dipotassium monohydrogen phosphate (K ₂ HPO ₄ ), diammonium monohydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ), etc .; sodium phosphite (Na ₂ HPO ₃ ), potassium phosphite Phosphites such as (K ₂ HPO ₃ ); sodium hypophosphite (NaH ₂ PO ₂ ), potassium hypophosphite (KH ₂ PO ₂ ), ammonium hypophosphite (NH ₄ H ₂ PO ₂ ) And other hypophosphites. Among them, from the viewpoint of achieving both high-speed polishing and low surface roughness, preferably, disodium monohydrogen phosphate, dipotassium monohydrogen phosphate, sodium phosphite, sodium hypophosphite, and ammonium hypophosphite are preferable. At least one inorganic phosphate selected from the group consisting of: at least one inorganic phosphate selected from the group consisting of disodium monohydrogen phosphate, dipotassium monohydrogen phosphate, and sodium phosphite, more preferably It is a phosphate, more preferably disodium monohydrogenphosphate. Also, these inorganic salts may have a hydrate structure.

  The content of the inorganic phosphate (component B) contained in the polishing composition of the present invention is preferably 0.0001% by mass or more, more preferably 0. from the viewpoint of achieving both high-speed polishing and low surface roughness. The content is 001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.02% by mass or more, and still more preferably 0.05% by mass or more and 0.08% by mass or more. The content of the inorganic phosphate (component B) contained in the polishing composition of the present invention is preferably 1% by mass or less, more preferably from the viewpoint of reducing the surface roughness of the object to be polished. It is 0.4% by mass or less, more preferably 0.3% by mass or less, and still more preferably 0.2% by mass or less.

  Content ratio of silica particles (component A) and inorganic phosphate (component B) in the polishing composition of the present invention [content of silica particles (mass%) / content of inorganic phosphate (mass %) Is preferably 2 or more, more preferably 20 or more, still more preferably 100 or more, preferably 10000 or less, more preferably 5000 or less, from the viewpoint of reducing the surface roughness of the object to be polished It is 2000 or less.

[Additive (Component C)]
The polishing composition of the present invention is an aqueous solution containing an alkanolamine, a fluorine-based compound having a perfluoroalkyl group, a water-soluble vinyl-based polymer, and a polyalkylene oxide skeleton, from the viewpoint of reducing surface roughness and improving polishing rate. Containing one or more additives selected from organic polymer compounds. Here, "water soluble" means having a solubility of 2 g / 100 ml or more in water.

(Alkanolamine)
The alkanolamine contained in the polishing composition of the present invention is preferably a compound represented by the following general formula (1) from the viewpoint of improving the removal rate of sapphire polishing debris and the dispersibility of the silica particles. However, in the general formula (1), a is 2 or more and 5 or less, b is 1 or more and 3 or less, c is 0 or more and 2 or less, and b + c = 3.
(H) _c N [(CH ₂ ) _a OH] _b (1)

In general formula (1), (CH ₂ ) _a represents an alkylene group having 2 or more and 5 or less carbon atoms, but from the viewpoint of improving the removal rate of sapphire polishing scraps and the dispersibility of silica particles, a is Preferably, it is 2 or more, and in view of the basicity of alkanolamine, a is preferably 5 or less. Specifically, the alkanolamine contained in the polishing composition of the present invention is ethanolamine, propanolamine, butanolamine, pentanolamine, diethanolamine, dipropanolamine, dibutanolamine, dipentanolamine, triethanolamine And tripropanolamine, tributanolamine, and tripentanolamine, but from the group consisting of ethanolamine, diethanolamine, and triethanolamine from the viewpoint of improving the removal rate of sapphire polishing debris and improving the dispersibility of silica particles. One or more selected alkanolamines are more preferred.

  The content of the alkanolamine contained in the polishing composition of the present invention is preferably 0.1% by mass or more, more preferably 0.1% by mass from the viewpoint of improving the removal rate of sapphire polishing debris and improving the dispersibility of silica particles. It is 5% by mass or more, more preferably 0.7% by mass or more, and preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less from the viewpoint of economy.

(Fluorinated compound having a perfluoroalkyl group)
The fluorine compound having a perfluoroalkyl group contained in the polishing composition of the present invention reduces the frictional resistance between the sapphire plate to be polished and the polishing pad, and the silica particles are between the sapphire plate to be polished and the polishing pad. From the viewpoint of improving the circulation, the compound is preferably a compound represented by the following general formula (2). However, in general formula (2), n and m are 1 or more and 10 or less as n, 0 or more and 3 or less as m, or 2 or more and 13 or less as n + m, X is an amino group, carboxylic acid group, ammonium group, amine oxide Or betaine.
CF ₃ (CF ₂ ) _n (CH ₂ ) _m X (2)

  In the general formula (2), n represents the number of carbon atoms in the chain-like fluoroethyl group, but preferably 1 or more, from the viewpoint of improving the circulation of the silica particles between the polishing sapphire plate and the polishing pad. It is more preferably 3 or more, further preferably 4 or more, and preferably 10 or less, more preferably 6 or less from the viewpoint of the dissolution rate of the fluorine-containing compound having a perfluoroalkyl group in water. m represents the number of carbon atoms of the alkylene group, but is preferably 0 or more and 3 or less from the viewpoint of easiness of synthesis of the fluorine-based compound having a perfluoroalkyl group. The fluorine-based compound having a perfluoroalkyl group contained in the polishing liquid composition of the present invention is, among the compounds represented by the above general formula (2), recyclability between the abrasive sapphire plate to be polished of silica particles and the polishing pad. From the viewpoint of improving the properties, at least one fluorine system selected from the group consisting of perfluoroalkylamino acid salts, perfluoroalkylcarboxylates, perfluoroalkyltrialkylammonium salts, perfluoroalkylamine oxides, and perfluoroalkylbetaines The compound is more preferable, and at least one fluorine-based compound selected from perfluoroalkylbetaine and perfluoroalkylamine oxide is more preferable.

  The content of the fluorine-containing compound having a perfluoroalkyl group contained in the polishing composition of the present invention is preferably 0.0001% by mass from the viewpoint of improving the circulation between the sapphire plate to be polished and the polishing pad. Or more, more preferably 0.0005% by mass or more, still more preferably 0.001% by mass, still more preferably 0.005% by mass, and from the viewpoint of economy, preferably 2% by mass or less, more preferably 1 It is at most mass%, more preferably at most 0.1 mass%, even more preferably at most 0.01 mass%.

  When the polishing composition of the present invention contains a water-soluble additive of at least one of an alkanolamine and a fluorine compound having a perfluoroalkyl group, the alkanolamine from the viewpoint of reduction of surface roughness and improvement of polishing rate. It is preferable to include both of the above and a fluorine-based compound having a perfluoroalkyl group. The combination of an alkanolamine and a fluorine compound having a perfluoroalkyl group is preferably diethanolamine and perfluoroalkyl betaine, triethanolamine and perfluoroalkylamine oxide, from the viewpoint of achieving both reduction in surface roughness and improvement in polishing rate. , Triethanolamine and perfluoroalkylbetaine, but more preferably triethanolamine and perfluoroalkylbetaine. When the polishing composition of the present invention contains both an alkanolamine and a fluorine-based compound having a perfluoroalkyl group, the mass ratio thereof (an alkanolamine / a fluorine-based compound having a perfluoroalkyl group) has a surface roughness. From the viewpoint of reducing the polishing rate and improving the polishing rate, it is preferably 80 or more, and preferably 500 or less.

(Surface adsorbent)
The polishing composition of the present invention contains, from the viewpoint of surface roughness reduction, at least one surface adsorbent selected from the group consisting of water-soluble vinyl polymers and water-soluble polymer compounds containing a polyalkylene oxide skeleton. . The water-soluble vinyl polymer is preferably selected from polyacrylic acid, polyvinyl alcohol, polyvinyl pyrrolidone, and n-polyvinyl formamide from the viewpoint of reducing the surface roughness by adsorbing to the surface of the silica particles and the sapphire plate to be polished. One or more surface adsorbents. The water-soluble polymer compound containing a polyalkylene oxide skeleton is preferably a polyalkylene glycol from the viewpoint of reducing the surface roughness by adsorbing to the surface of the silica particles and the sapphire plate to be polished, and is preferably polyethylene glycol (more preferably polyethylene glycol). PEG), polyethylene oxide (PEO), polypropylene glycol (PPG), and one or more selected from the group consisting of ethylene glycol and propylene glycol copolymers. Among the above-mentioned surface adsorbents, from the viewpoint of improving the polishing rate, it is preferably a water-soluble polymer compound having a polyalkylene oxide skeleton, more preferably polyethylene glycol.

  The weight average molecular weight of the water-soluble vinyl polymer contained in the polishing composition of the present invention is preferably 1000 or more, more preferably 5000 or more, because it easily adsorbs to the surface of the object to be polished and forms a protective film. Preferably it is 1000000 or less, More preferably, it is 500000 or less. Here, the weight average molecular weight of the surface adsorbent can be determined by the method described in the examples described later.

  The weight average molecular weight of the water-soluble polymer compound having a polyalkylene oxide skeleton contained in the polishing composition of the present invention is preferably 1,000 or more, because it easily adsorbs to the surface of the object to be polished and forms a protective film. More preferably, it is 5000 or more, Preferably it is 100000 or less, More preferably, it is 50000 or less. Here, the weight average molecular weight of the surface adsorbent can be determined by the method described in the examples described later.

  The content of the surface adsorbent contained in the polishing composition of the present invention is preferably 0.002% by mass or more, more preferably 0.004% by mass or more, still more preferably 0 from the viewpoint of reducing surface roughness. The content is preferably not less than 0.5% by mass, more preferably not more than 0.2% by mass, and still more preferably not more than 0.1% by mass from the viewpoint of polishing rate.

[Aqueous medium (component D)]
Examples of the aqueous medium (component D) contained in the polishing composition of the present invention include water such as ion-exchanged water and ultrapure water, or a mixed medium of water and a solvent. Solvents which can be mixed (eg, alcohols such as ethanol) are preferred. Among them, ion exchange water or ultrapure water is more preferable, and ultrapure water is more preferable. When Component D of the present invention is a mixed medium of water and a solvent, the ratio of water to the entire mixed medium is not particularly limited, but from the viewpoint of economy, 95% by mass or more is preferable, 98 % Or more is more preferable, substantially 100% by mass is further preferable, and 100% by mass is further more preferable.

  The content of the aqueous medium (component D) in the polishing composition of the present invention is not particularly limited, and may be the remainder of component A, component B, component C, and optional components described later.

  The pH of the polishing composition of the present invention at 25 ° C. is pH 8 or more, preferably 9 or more, more preferably 10 or more from the viewpoint of improving the polishing rate, and the dissolution suppression of silica particles and the stability improvement From the viewpoint, it is preferably less than 14, and more preferably less than 13. The pH at 25 ° C. of the polishing composition of the present invention can be determined by the method described in the examples described later.

  The polishing composition of the present invention may further contain conventionally known optional components depending on the use application. When the polishing composition of the present invention is, for example, a polishing composition for sapphire substrates for electronic components such as semiconductor devices (for example, a polishing composition for sapphire substrates for LEDs), the polishing composition of the present invention May further contain a surfactant other than the component C, a rust inhibitor, a dispersant, a pH adjuster, an antibacterial agent, an antistatic agent and the like. The polishing composition of the present invention may contain an oxidizing agent such as hydrogen peroxide if it is in a small amount, but it is preferable not to contain an oxidizing agent such as hydrogen peroxide from the viewpoint of improving the polishing rate.

[Method of preparing polishing composition]
The polishing composition of the present invention can be prepared by mixing the respective components by a known method. The polishing composition is usually produced as a concentrate from the viewpoint of economy, and is often diluted at the time of use. The polishing composition may be used as it is, or it may be diluted if it is a concentrated solution. When the concentrate is diluted, the dilution ratio is not particularly limited, and can be appropriately determined according to the concentration of each component in the concentrate, polishing conditions, and the like. In addition, content of each above-mentioned component is content at the time of use.

  Next, an example of a method of producing a sapphire plate of the present invention using the polishing composition of the present invention and an example of a method of polishing a sapphire substrate to be polished of the present invention will be described.

[Object to be polished]
An example of the method for producing a sapphire plate of the present invention (sometimes abbreviated as "an example of the method for producing the present invention"), and an example of a method for polishing a sapphire plate to be polished of the present invention ("the polishing method of the present invention There is no particular limitation on the shape of the object to be polished, which may be abbreviated as “an example.” There is no particular limitation, and for example, it is not only a shape having flat portions such as disc, plate, slab or prism, but also lenses It may be a shape having a curved surface portion, etc. The object to be polished is various, such as a sapphire plate used as a cover glass of a portable terminal device such as a smartphone, a sapphire substrate for an LED, etc., but the polishing composition of the present invention is a sapphire substrate for an LED, a smartphone, etc. It is suitable as a polishing composition used in the polishing step of the method of manufacturing a sapphire plate used as a cover glass of a portable terminal device.

  Therefore, an example of the method for producing a sapphire plate of the present invention is a method for producing a sapphire plate such as a sapphire substrate for LEDs or a sapphire plate for cover glass of portable terminal devices such as smartphones. And polishing the sapphire plate. Further, an example of the method for polishing a sapphire plate to be polished according to the present invention is a method for polishing a sapphire plate such as a sapphire substrate for LEDs or a sapphire plate for cover glass of portable terminal devices such as smartphones. Polishing the sapphire plate using a metal.

  In the step of polishing the sapphire plate to be polished, a first polishing step (rough polishing step) of planarizing a wafer obtained by slicing a sapphire single crystal ingot into a thin disk shape and etching of the roughly polished wafer The present invention is divided into a second polishing step (finishing polishing) for mirror-finishing the wafer surface, but the polishing composition of the present invention can be used in any of the first polishing step and the second polishing step. However, the polishing composition of the present invention is preferably used in the second polishing step from the viewpoint of improving the surface smoothness and productivity of the sapphire plate. In the first polishing step, it is general to use a polishing composition containing diamond as abrasive grains.

  There is no restriction | limiting in particular as a polishing apparatus used by one example of the manufacturing method of this invention, and one example of the grinding | polishing method of this invention, A jig (Carrier: Material made of glass epoxy etc.) which holds a to-be-polished sapphire plate And a double-side polishing apparatus and a single-side polishing apparatus may be used.

  The polishing pad is not particularly limited, and conventionally known polishing pads can be used. Examples of the material of the polishing pad include organic polymers and the like, and examples of the organic polymers include polyurethane and the like. The shape of the polishing pad is preferably non-woven. For example, SUBA 800 (manufactured by Nitta Haas Co., Ltd.) is suitably used as a non-woven fabric polishing pad.

  In one example of the manufacturing method of the present invention and one example of the polishing method of the present invention using the polishing apparatus, the sapphire plate is sandwiched by a polishing table which holds the sapphire plate to be polished with a carrier and a polishing pad is attached. The polishing composition of the present invention is supplied between a polishing pad and a sapphire plate to be polished, and the polishing pad and / or the sapphire plate to be polished are moved while contacting the sapphire plate to be polished and the polishing pad. And polishing the sapphire plate.

The polishing load in one example of the production method of the present invention and one example of the polishing method is preferably 50 g / cm ² or more, more preferably 100 g / cm ² or more, and still more preferably 150 g / cm ² or more from the viewpoint of improving the polishing rate. 200 g / cm ² or more is even more preferable. Further, the polishing load, device, considering the durability, such as pad, preferably 400 g / cm ² or less, 350 g / cm ² or less being more preferred. The adjustment of the polishing load can be performed by the load of air pressure or a weight on a surface plate, a sapphire plate to be polished, or the like. The polishing load means the pressure of the platen applied to the polishing surface of the sapphire plate to be polished during polishing.

  The method for supplying a polishing composition according to the present invention includes a method of supplying a pump or the like between a polishing pad and a sapphire plate to be polished in a state in which components of the polishing composition are sufficiently mixed in advance; It is possible to use a method of mixing and supplying the above-mentioned components, etc. A method of supplying a polishing composition between a polishing pad and a sapphire plate with a pump or the like in a state in which the components of the polishing composition are sufficiently mixed in advance from the viewpoint of improving polishing speed and reducing load of apparatus Is preferred.

The supply rate of the polishing composition is preferably 20 mL / min or less, more preferably 10 mL / min or less, and still more preferably 5 mL / min or less, per cm ^{2 of the} sapphire plate from the viewpoint of cost reduction. The supply rate is preferably 0.01 mL / min or more per 1 cm ^{2 of the} polished sapphire plate, more preferably 0.1 mL / min or more, and still more preferably 0.5 mL / min or more from the viewpoint of improving the polishing rate.

  In one example of the production method of the present invention and one example of the polishing method of the present invention, since the polishing composition of the present invention is used, the polishing rate of the sapphire plate to be polished is fast, and the surface roughness of the substrate surface after polishing is obtained. It can be reduced.

  In another example of the manufacturing method of the present invention, the polishing liquid composition used in the step of supplying the polishing composition of the present invention to the polishing sapphire plate to polish the sapphire plate, and the polishing liquid composition used in the step Polishing an object-to-be-polished sapphire plate different from the object-to-be-polished sapphire plate using an object.

  The present invention further discloses the following <1> to <25>.

<1> At least one selected from a water-soluble polymer compound containing a silica particle, an inorganic phosphate, an alkanolamine, a fluorine-based compound having a perfluoroalkyl group, a water-soluble vinyl-based polymer, and a polyalkylene oxide skeleton The polishing liquid composition for sapphire boards which have the pH of 8 or more in 25 degreeC, and the additive of these.
<2> The inorganic phosphate is preferably at least one inorganic phosphate selected from the group consisting of orthophosphate, phosphite and hypophosphite, more preferably orthophosphate The polishing liquid composition for sapphire plates as described in said <1> which is 1 or more types of inorganic phosphates chosen from the group which consists of and phosphite.
<3> The inorganic phosphate is preferably at least one inorganic phosphate selected from the group consisting of alkali metal salts, alkaline earth metal salts and ammonium salts, more preferably sodium salts and potassium salts The polishing liquid composition for sapphire plates as described in said <1> or <2> which is at least 1 sort (s) chosen from and and ammonium salt.
<4> The inorganic phosphate is preferably sodium phosphate (Na ₃ PO ₄ ), potassium phosphate (K ₃ PO ₄ ), disodium monohydrogen phosphate (Na ₂ HPO ₄ ), monohydrogen phosphate monobasic Sodium (NaH ₂ PO ₄ ), monopotassium dihydrogen phosphate (KH ₂ PO ₄ ), monoammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ), dipotassium monohydrogen phosphate (K ₂ HPO ₄ ), phosphorus Diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ), sodium phosphite (Na ₂ HPO ₃ ), potassium phosphite (K ₂ HPO ₃ ), sodium hypophosphite (NaH ₂ PO ₂ ), and sodium hypophosphite (NaH ₂ PO ₂ ) It is at least one inorganic phosphate selected from potassium phosphite (KH ₂ PO ₂ ) and ammonium hypophosphite (NH ₄ H ₂ PO ₂ ), more preferably disodium monohydrogen phosphate, phosphorus Oxygen and hydrogen At least one inorganic phosphate selected from the group consisting of sodium, sodium phosphite, sodium hypophosphite, and ammonium hypophosphite, more preferably disodium monohydrogen phosphate, monohydrogen phosphate At least one inorganic phosphate selected from the group consisting of dipotassium and sodium phosphite, and even more preferably disodium monohydrogenphosphate, in any one of the above <1> to <3> Polishing liquid composition for sapphire boards as described.
<5> The content of the inorganic phosphate contained in the polishing composition for a sapphire plate is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, and still more preferably 0.01% by mass. %, Still more preferably 0.02% by mass or more, still more preferably 0.05% by mass or more, still more preferably 0.08% by mass or more, preferably 1% by mass or less, more preferably 0. The polishing composition for a sapphire plate according to any one of <1> to <4>, which is 4% by mass or less, more preferably 0.3% by mass or less, still more preferably 0.2% by mass or less.
<6> The content ratio of the silica particles to the inorganic phosphate [content of silica particles (mass%) / content of inorganic phosphate (mass%) contained in the polishing liquid composition for sapphire plate ] Is preferably 2 or more, more preferably 20 or more, still more preferably 100 or more, preferably 10000 or less, more preferably 5000 or less, still more preferably 2000 or less, any one of the above <1> to <5> Polishing liquid composition for sapphire boards given in a.
<7> The polishing composition for a sapphire plate according to any one of <1> to <6>, wherein the alkanolamine is preferably a compound represented by the following general formula (1).
(H) _c N [(CH ₂ ) _a OH] _b (1)
However, in the general formula (1), a is 2 or more and 5 or less, b is 1 or more and 3 or less, c is 0 or more and 2 or less, and b + c = 3.
<8> The alkanolamine is preferably ethanolamine, propanolamine, butanolamine, pentanolamine, diethanolamine, dipropanolamine, dibutanolamine, dipentanolamine, triethanolamine, tripropanolamine, tributanolamine, And <1> at least one alkanolamine selected from the group consisting of ethanolamine, diethanolamine, and triethanolamine, more preferably one or more alkanolamines selected from the group consisting of Polishing liquid composition for sapphire boards as described.
<9> The content of the alkanolamine contained in the polishing liquid composition for a sapphire plate is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and still more preferably 0.7% by mass or more. The polishing liquid composition for a sapphire plate according to any one of <1> to <8>, wherein the content is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less.
<10> The polishing liquid composition for a sapphire plate according to any one of <1> to <9>, wherein the fluorine-based compound having a perfluoroalkyl group is preferably a compound represented by the following general formula (2) .
CF ₃ (CF ₂ ) _n (CH ₂ ) _m X (2)
However, in general formula (2), n and m are 1 or more and 10 or less as n, 0 or more and 3 or less as m, or 2 or more and 13 or less as n + m, X is an amino group, carboxylic acid group, ammonium group, amine oxide Or betaine.
<11> The fluorine-based compound having a perfluoroalkyl group is preferably a perfluoroalkylamino acid salt, a perfluoroalkylcarboxylic acid salt, a perfluoroalkyltrialkylammonium salt, a perfluoroalkylamine oxide, and a perfluoroalkylbetaine. The polishing liquid for a sapphire plate according to <10>, which is at least one fluorine-based compound selected from the group consisting of at least one fluorine-based compound selected from perfluoroalkylbetaine and perfluoroalkylamine oxide. Composition.
<12> The content of the fluorine-based compound having a perfluoroalkyl group in the polishing liquid composition for sapphire plate is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, still more preferably 0. The content is 001% by mass, more preferably 0.005% by mass, preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.1% by mass or less, still more preferably 0.01% by mass The polishing liquid composition for sapphire boards in any one of said <1> to <11> which is the following.
<13> The polishing liquid composition for a sapphire plate contains both the alkanolamine and the fluorine compound having the perfluoroalkyl group, and the combination of the alkanolamine and the fluorine compound having the perfluoroalkyl group is preferable. Are selected from diethanolamine and perfluoroalkylbetaine, triethanolamine and perfluoroalkylamine oxide, triethanolamine and perfluoroalkylbetaine, more preferably triethanolamine and perfluoroalkylbetaine from <1> to <6>. Polishing liquid composition for sapphire boards given in either.
<14> The polishing liquid composition for a sapphire plate according to <13>, wherein the mass ratio (the alkanolamine / fluorinated compound having a perfluoroalkyl group) is preferably 80 or more, preferably 500 or less.
<15> The water-soluble vinyl polymer is preferably one or more compounds selected from polyacrylic acid, polyvinyl alcohol, polyvinyl pyrrolidone, and n-polyvinyl formamide, and more preferably polyvinyl alcohol, polyvinyl pyrrolidone, and n− The polishing liquid composition for sapphire plates in any one of said <1> to <14> which is 1 or more types of compounds chosen from a polyvinyl formamide.
<16> The weight-average molecular weight of the water-soluble vinyl polymer is preferably 1000 or more, more preferably 5000 or more, preferably 1,000,000 or less, more preferably 500000 or less. The polishing liquid composition for sapphire plates in any one.
<17> The water-soluble polymer compound containing a polyalkylene oxide skeleton is preferably selected from polyalkylene glycols, more preferably polyethylene glycol (PEG), polypropylene glycol (PPG), and a copolymer of ethylene glycol and propylene glycol The polishing liquid composition for sapphire boards in any one of said <1> to <16> which is at least 1 type of compound.
<18> The weight average molecular weight of the water-soluble polymer compound containing a polyalkylene oxide skeleton is preferably 1000 or more, more preferably 5000 or more, preferably 1,000,000 or less, more preferably 500000 or less. ] The polishing liquid composition for sapphire boards in any one of <17>.
<19> The polishing composition for a sapphire plate contains, as a surface adsorbent, at least one additive of the water-soluble vinyl polymer and the water-soluble polymer compound containing the polyalkylene oxide skeleton, and the surface adsorption The content of the agent is preferably 0.002% by mass or more, more preferably 0.004% by mass or more, still more preferably 0.006% by mass or more, preferably 0.5% by mass or less, more preferably The polishing liquid composition for sapphire plates in any one of said <1> to <18> which is 0.2 mass% or less, More preferably, it is 0.1 mass% or less.
<20> The pH of the polishing composition for a sapphire plate at 25 ° C. is preferably 9 or more, more preferably 10 or more, preferably less than 14 and more preferably less than 13. The polishing liquid composition for sapphire plates in any one of <19>.
<21> The content of the silica particles is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 40% by mass or less, in terms of SiO ₂ concentration. The polishing composition for a sapphire plate according to any one of <1> to <20>, wherein the following is more preferable, and 25 mass% or less is more preferable.
<22> The average secondary particle size (average particle size) measured by the dynamic light scattering method of the silica particles is preferably 10 nm or more, more preferably 50 nm or more, still more preferably 80 nm or more, and preferably 500 nm or less, The polishing liquid composition for sapphire plates in any one of said <1> to <21> whose 300 nm or less is more preferable and 200 nm or less is still more preferable.
<23> The average primary particle diameter of the silica particles is preferably 500 nm or less, more preferably 300 nm or less, still more preferably 200 nm or less, still more preferably 150 nm or less, preferably 45 nm or more, and more preferably 70 nm or more. The polishing liquid composition for sapphire plates in any one of <1> to <22>.
<24> A sapphire comprising the step of supplying the polishing composition for a sapphire plate according to any one of <1> to <23> to a sapphire plate to be polished, and polishing the sapphire plate to be polished How to make a board.
<25> A process for polishing a sapphire plate by supplying the polishing composition for a sapphire plate according to any one of <1> to <23> to a sapphire plate to be polished, and polishing the sapphire plate to be polished Polishing method of sapphire plate.

  The polishing liquid compositions of Examples 1 to 20 and Comparative Examples 1 to 12 were prepared as described below. The contents and types of the silica particles, the inorganic phosphate or the comparison target compound thereof and the additives in the polishing liquid compositions of Examples 1 to 20 and Comparative Examples 1 to 12 were as described in Table 1, respectively. . The remaining component is ion exchanged water.

[Examples 1 to 20]
After a source of inorganic phosphate was added to a beaker containing 500 g of ion-exchanged water so that the concentration of the active component reached a predetermined value, an additive was then added. Thereafter, 625 g of an aqueous dispersion of 40% by mass colloidal silica (average primary particle size 80 nm, Catalodic SI-80P manufactured by JGC Catalysts Chemical Co., Ltd.) is added, and the mixture is stirred to contain an inorganic phosphate and an additive. An aqueous silica dispersion was obtained. Immediately thereafter, the pH was adjusted to a value described in Table 1 using a pH adjuster to obtain polishing liquid compositions of Examples 1 to 20. In the case of increasing the pH value as the pH adjusting agent, the one obtained by diluting a 48% by mass aqueous sodium hydroxide solution (manufactured by Kanto Chemical Co., Ltd.) to 0.1% by mass with water and reducing the pH value Used a solution of 62.5% sulfuric acid (manufactured by Tayca) diluted with water to 0.1% by mass. In addition, when the inorganic phosphate is disodium monohydrogenphosphate, phosphorous acid is used as a source, such as disodium monohydrogenphosphate dihydrate (manufactured by Wako Pure Chemical Industries, Ltd.) When it is sodium, sodium phosphite pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) is used as its source, and when it is dipotassium monohydrogen phosphate, it is used as its source. When potassium (Wako Pure Chemical Industries, Ltd.) is used and diammonium monohydrogen phosphate is used, diammonium monohydrogen phosphate (manufactured by Wako Pure Chemical Industries, Ltd.) is used as its supply source .

Comparative Example 1
A polishing composition of Comparative Example 1 was prepared in the same manner as the polishing composition of Example 1, except that the inorganic phosphate or the source of the comparison target compound and the additive were not added.

Comparative Example 2
A polishing composition of Comparative Example 2 was prepared in the same manner as the polishing composition of Example 1, except that triethanolamine was not added and the pH of the polishing composition was 10.0.

Comparative Example 3
A polishing composition of Comparative Example 3 was prepared in the same manner as the polishing composition of Example 3 except that the inorganic phosphate or the source of the comparison target compound was not added.

Comparative Example 4
A polishing composition of Comparative Example 4 was prepared in the same manner as the polishing composition of Example 4 except that the inorganic phosphate or the source of the comparison target compound was not added.

Comparative Example 5
A polishing composition of Comparative Example 5 was prepared in the same manner as the polishing composition of Example 3 except that sodium chloride was added as a compound to be compared with the inorganic phosphate.

Comparative Example 6
A polishing composition of Comparative Example 6 was prepared in the same manner as the polishing composition of Example 4 except that sodium chloride was added as a compound to be compared with the inorganic phosphate.

Comparative Example 7
Comparison was carried out in the same manner as in the polishing composition of Example 3 except that HEDP (1-hydroxyethylidene-1,1-diphosphonic acid, manufactured by Italmatch Japan) was added as a compound to be compared with the inorganic phosphate. The polishing composition of Example 7 was prepared.

Comparative Example 8
The polishing liquid of Comparative Example 8 was prepared in the same manner as the polishing composition of Example 3, except that ATMP (amino tri (methylene phosphonic acid) (manufactured by Italmatch Japan) was added as a compound to be compared with the inorganic phosphate. The composition was prepared.

Comparative Example 9
Comparative Example was the same as the polishing composition of Example 3 except that 62.5% sulfuric acid (manufactured by Tayca) was used as a pH adjuster, and the pH of the polishing composition at 25 ° C. was 2.0. A polishing composition of 7 was prepared.

Comparative Example 10
A polishing composition of Comparative Example 8 was prepared in the same manner as the polishing composition of Example 3 except that the pH of the polishing composition was 7.1.

Comparative Example 11
45% by mass of alumina particles (average secondary particle diameter: 0.8 μm, alpha conversion rate) instead of 625 g of 40% by mass colloidal silica (average primary particle diameter: 80 nm, cataloid SI-80P, manufactured by JGC Catalysts Chemical Co., Ltd.) A polishing composition of Comparative Example 9 was prepared in the same manner as the polishing composition of Example 3, except that 488 g of a 90% aqueous solution with a crystallite size of 32 nm was added.

Comparative Example 12
A polishing composition of Comparative Example 12 was prepared in the same manner as the polishing composition of Comparative Example 11 except that the inorganic phosphate or the source of the comparison target compound was not added.

[Method of measuring volume average particle diameter (D50) of alumina particles]
The volume average particle diameter (average secondary particle diameter) of the alumina particles (abrasive particles) used in the preparation of the polishing composition of Comparative Examples 11 and 12 is 0.5% Poise 530 (manufactured by Kao; special polycarboxylic acid) Type polymer surfactant) aqueous solution is used as a dispersion medium, the dispersion medium is charged into the following measuring apparatus, and then a sample (alumina particles) is charged so that the transmittance is 75 to 95%, and then 5 After ultrasonication for a minute, it was measured.
Measuring equipment: Horiba, Ltd. Laser diffraction / scattering type particle size distribution analyzer LA920
Circulation strength: 4
Ultrasonic intensity: 4
The particle diameter at which the cumulative volume frequency of the obtained volume distribution particle diameter is 50% is defined as the volume average particle diameter (D50) of the alumina particles, and is shown in Table 1 as the average secondary particle diameter.

[Method for measuring the degree of alpha conversion and crystallite size of alumina particles]
20 g of the alumina slurry was dried at 105 ° C. for 5 hours, and the obtained dried product was crushed in a mortar to obtain a sample for powder X-ray diffraction. Each sample was analyzed by a powder X-ray diffraction method, and the peak area on the 104 side was compared with the peak area of α-alumina (manufactured by Showa Denko, WA-1000) having a degree of gelatinization of 99.9%. The measurement conditions by powder X-ray diffraction were as follows.
(Measurement condition)
Device: Powder X-ray analyzer RINT2500VC manufactured by Rigaku Corporation
X-ray generated voltage: 40kV
Radiation: Cu-Kα1 ray (λ = 0.154050 nm)
Current: 120 mA
Scan Speed: 10 ° / min Measurement step: 0.02 ° / min α conversion rate (%) = specific peak area of α-alumina ピ ー ク WA-1000 peak area × 100
In addition, the crystallite size was calculated from the obtained powder X-ray diffraction spectrum, using a powder X-ray diffraction pattern comprehensive analysis software JADE (MDI company, automatic calculation according to Schiller's equation) attached to the powder X-ray diffractometer. The calculation processing by the above software was performed based on the instruction manual of the above software (Jade (Ver. 5) software, instruction manual Manual No. MJ13133E02, Rigaku Denki Co., Ltd.).

<Measurement of Average Primary Particle Size of Silica Particles>
The average primary particle size of the silica particles is, as described below, a number average of particle sizes determined as equivalent circle diameters measured in an electron microscope (TEM) observation image. A photograph of silica particles observed with a transmission electron microscope (TEM) manufactured by JEOL Ltd. (trade name "JEM-2000FX", 80 kV, 1 to 50,000 magnifications) is taken into a computer as image data by a scanner, and analysis software "WinROOF (Ver The particle diameter determined as the equivalent circle diameter of one silica particle per 1000 to 2000 silica particle data is determined using “3.6.” (Sold by: Mitani Corporation), and the average primary particle diameter is determined by number average. I asked.

[Measurement of average secondary particle size of silica particles]
The average secondary particle size (dispersed particle size) of the silica particles (abrasive particles) is obtained by measurement under the following conditions using a dynamic light scattering (DLS) particle size distribution analyzer (manufactured by Malvern, Zetasizer Nano S). The volume conversion average particle diameter obtained was determined as an average secondary particle diameter (dispersed particle diameter).
Solvent: water (refractive index 1.333)
Abrasive grains: Colloidal silica (refractive index 1.45, damping coefficient 0.02)
Measurement temperature: 25 ° C

[Measurement of BET specific surface area of silica particles]
Regarding the specific surface area of the silica particles, about 0.1 g of the measurement sample is refined to 4 digits after the decimal point in the measurement cell for the powder sample dried at 100 ° C. for 24 hours, and immediately before the measurement of the specific surface area under an atmosphere of 200 ° C. After drying for 30 minutes, measurement was performed by a nitrogen adsorption method (BET method) using a specific surface area measurement device (Micromeritic automatic specific surface area measurement device Flowsorb III 2305, manufactured by Shimadzu Corporation). The BET specific surface area of the silica particle used for preparation of the polishing liquid composition of Examples 1-20 and Comparative Examples 1-12 was 40 m < ² > / g.

[Measurement of Weight Average Molecular Weight of Water-Soluble Vinyl Polymer, Water-Soluble Polymer Compound Containing Polyalkylene Oxide Skeleton]
The said weight average molecular weight was measured by the gel permeation chromatography (GPC) method in the following measurement conditions.
[GPC conditions]
Device: HLC-8320 GPC (Tosoh Corporation, detector integrated type)
Column: GMPWXL + GMPWXL (anion)
Eluent: 0.2 M phosphate buffer / CH3CN = 9/1 (volume ratio)
Temperature: 40 ° C
Flow rate: 0.5mL / min
Sample size: 5 mg / mL
Detector: RI
Conversion standard: Monodispersed polyethylene glycol of known molecular weight

<PH measurement of polishing composition>
The pH of the polishing composition was measured at 25 ° C. using a pH meter (HM-30G, manufactured by Toa Denpa Kogyo Co., Ltd.).

<Abrasive evaluation>
Circulating polishing was performed for 3 hours using the polishing composition of Examples 1 to 20 and Comparative Examples 1 to 12 on a sapphire plate (c surface) of 3 inches under the following polishing conditions. And the weight change before and behind grinding | polishing of a sapphire board was calculated | required, and the grinding | polishing speed (micrometer / h) was computed from sapphire density (3.98 g / cm < ³ >) and sapphire board area (45.6 cm < ² >). The polishing rate in the case of using the polishing composition of Examples 1 to 20 and Comparative Examples 1 to 12 is a relative value in the case of setting the polishing rate of the case of using the polishing composition of Comparative Example 1 to "100". And shown in Table 1.

(Polishing conditions)
Single-side Polishing Machine (Technolize TR15M-TRK1, Plate diameter 38 cm)
Non-woven fabric polishing pad (Nita Hearth SUBA 800)
Polishing load 300g / cm ²
Plate rotation speed 120rpm
Carrier rotation speed 120rpm
Polishing fluid flow rate 80 mL / min (circulation)

[Method of measuring surface roughness]
Using AFM (Digital Instrument NanoScope IIIa Multi Mode AFM), measure the center line average roughness AFM-at two different places in the central part of the inner and outer peripheral edges of the sapphire plate after cleaning under the conditions shown below. Ra was measured. The average value of the two points is shown as “surface roughness” and is shown in Table 1. The smaller the value is, the more the deterioration of the surface roughness is suppressed.
[Measurement conditions of AFM]
Mode: Tapping mode
Area: 5 × 5 μm
Scan rate: 1.0 Hz
Cantilever: OMCL-AC160TS-C3
Line: 512 × 512

  As shown in Table 1, when the polishing composition of the example is used, both high-speed polishing and low surface roughness can be achieved, compared to the case of using the polishing composition of the comparative example.

  As explained above, in the polishing of a sapphire plate to be polished using the polishing composition of the present invention, the polishing rate is high, and good surface smoothness is ensured for the sapphire plate after polishing. Therefore, using the polishing composition of the present invention, for example, the productivity of a sapphire plate or the like used for manufacturing an LED or a cover glass of a portable terminal device such as a smartphone can be improved.

Claims (7)

Silica particles,
Inorganic phosphate,
Water-soluble vinyl polymers, and viewed including the one or more additives selected from water-soluble polymer compound containing a polyalkylene oxide backbone and,
The content ratio of the silica particles to the inorganic phosphate [content of silica particles / content of inorganic phosphate] is 2 or more and 10000 or less.
Polishing liquid composition for sapphire boards whose pH at 25 ° C is 8 or more. The polishing solution according to claim 1, wherein the inorganic phosphate is at least one inorganic phosphate selected from the group consisting of orthophosphate, phosphite and hypophosphite. Composition.   The polishing solution according to claim 1 or 2, wherein the inorganic phosphate is at least one inorganic phosphate selected from the group consisting of alkali metal salts, alkaline earth metal salts, and ammonium salts. Composition. The polishing liquid composition for a sapphire plate according to any one of claims 1 to 3 , wherein the water-soluble vinyl polymer is one or more compounds selected from polyvinyl alcohol, polyvinyl pyrrolidone and n-polyvinyl formamide. The water-soluble polymer compound containing a polyalkylene oxide skeleton is at least one compound selected from polyethylene glycol (PEG), polypropylene glycol (PPG), and a copolymer of ethylene glycol and propylene glycol. The polishing liquid composition for sapphire plates of any one of 4 . The manufacturing method of a sapphire board including the process of supplying the polish liquid composition for sapphire boards given in any 1 paragraph of Claims 1 to 5 to a polish sapphire board, and grinding the above-mentioned sapphire board for polish. . A sapphire plate to be polished comprising the step of supplying the polishing liquid composition for a sapphire plate according to any one of claims 1 to 5 to a sapphire plate to be polished, and polishing the sapphire plate to be polished. Polishing method.