JP2017190363A - Polishing liquid composition for sapphire plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing liquid composition for a sapphire plate which can achieve both high-speed polishing and reduction in thickness unevenness, and to provide a method of manufacturing a sapphire plate and a method of polishing a sapphire plate to be polished each using the composition.SOLUTION: The polishing liquid composition for a sapphire plate contains: abrasive grains A; at least one amphoteric surfactant B selected from an amphoteric surfactant B1 represented by alkyl dimethylamine oxide, amphoteric surfactants B2 represented by alkyl betaine and alkyl amidopropyl betaine, and an amphoteric surfactant B3 represented by 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine; and an aqueous medium.SELECTED DRAWING: None

Description

  The present invention relates to a polishing composition for a sapphire plate, a method for producing a sapphire plate using the same, and a method for 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, an artificial sapphire plate is used as a material for various applications such as an integrated circuit board, an infrared detection lens, a portable terminal device such as a watch and a smartphone. In particular, with the rapid spread of LEDs, the demand for sapphire plates used as substrates is rapidly increasing. The sapphire substrate for LED is desired to have 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 liquid composition is performed. By using abrasive grains having a hardness lower than that of the sapphire (α-alumina, Mohs hardness 9) plate, pits and scratches are not generated on the surface of the sapphire plate. However, although sapphire is excellent in mechanical, chemical, and thermal stability, there is a problem that the polishing rate is low in finish polishing.

  Patent Document 1 aims to polish an object to be polished at a high polishing rate, and to suppress generation of defects such as scratches on the surface of the object to be polished and generation of scratches on a polishing pad or a holding jig, As an additive for reducing unnecessary frictional resistance between the polishing pad and the object to be polished, for example, at least one selected from the group consisting of an anionic surfactant and an anionic water-soluble polymer A polishing composition containing an additive is disclosed. Patent Document 2 and Cited Document 3 disclose a fluorine-based compound having an alkanolamine compound and a perfluoroalkyl group for the purpose of polishing an object to be polished at a high polishing rate and reducing the surface roughness of the surface to be polished. A polishing composition comprising at least one of the compounds is disclosed. In Patent Document 4, a hydrophilic group is used for polishing a semiconductor substrate material, a glass substrate material, etc., for polishing an object to be polished at a high polishing rate, and improving the smoothness and uniformity of the surface to be polished. And a polishing composition containing a fluorine-containing compound having a fluorinated hydrocarbon group. Patent Document 5 discloses a polishing composition comprising a polymer compound having a sulfo group and / or a salt thereof and containing an aromatic ring for the purpose of achieving both a high polishing rate and a good quality of the surface to be polished. ing.

Japanese Patent Application Laid-Open No. 2015-203081 JP 2009-297818 A JP 2014-39054 A JP 2001-303027 A JP 2014-204064 A

  However, the amount of polishing in the vicinity of the outer periphery of the sapphire plate may be larger than the amount of polishing in the inner portion, and thickness unevenness may occur such that the thickness in the vicinity of the outer periphery is smaller than the thickness in the inner portion. . Further, for the purpose of improving productivity, it is desired to further improve the polishing rate of the sapphire plate.

  Accordingly, the present invention provides a polishing liquid composition for a sapphire plate, a method for producing a sapphire plate using the same, and a method for polishing a sapphire plate to be polished, which can achieve both high-speed polishing and reduction in thickness unevenness.

ただし、Ｒ¹及びＲ⁷は、同一又は異なって、炭素数が６以上２４以下の炭化水素基であり、Ｒ⁴は、炭素数が５以上２３以下の炭化水素基であり、Ｒ²，Ｒ³，Ｒ⁵，及びＲ⁶は、同一又は異なって、炭素数が１以上３以下の炭化水素基であり、Ｘは、ＣＨ₂又はＣＯＮＨ(Ｃ_nＨ_2n)であり、Ｙは、Ｃ_mＨ_2mであり、ｎは２以上４以下、ｍは１以上４以下である。 The polishing composition for sapphire plates of the present invention comprises abrasive grains A, an amphoteric surfactant B1 represented by the following formula (1), an amphoteric surfactant B2 represented by the following formula (2), and the following formula (3 Is a polishing liquid composition for sapphire plates containing at least one amphoteric surfactant B selected from the group consisting of amphoteric surfactants B3 represented by formula (1) and an aqueous medium.

R ¹ and R ⁷ are the same or different and are hydrocarbon groups having 6 to 24 carbon atoms, R ⁴ is a hydrocarbon group having 5 to 23 carbon atoms, R ² , R ³ , R ⁵ , and R ⁶ are the same or different and are hydrocarbon groups having 1 to 3 carbon atoms, X is CH ₂ or CONH (C _n H _2n ), and Y is C _m H _2m , n is 2 or more and 4 or less, and m is 1 or more and 4 or less.

  One example of the method for producing a sapphire plate of the present invention is a method for producing a sapphire plate, comprising a step of supplying the polishing composition for a sapphire plate of the present invention to the polished sapphire plate and polishing the polished sapphire plate. Is the method.

  Another example of the method for producing a sapphire plate of the present invention includes a step of supplying the polishing composition for a sapphire plate of the present invention to the polished sapphire plate and polishing the polished sapphire plate, and the above step. And a step of polishing a polished sapphire plate different from the polished sapphire plate using the used sapphire plate polishing liquid composition.

  An example of a polishing method for a polished sapphire plate of the present invention includes a step of supplying the polishing composition for a sapphire plate of the present invention to the polished sapphire plate and polishing the polished sapphire plate. A polishing method for a polished sapphire plate.

  ADVANTAGE OF THE INVENTION According to this invention, the polishing liquid composition for sapphire plates which can perform both high-speed grinding | polishing and reduction of thickness nonuniformity, the manufacturing method of a sapphire board using the same, and the grinding | polishing method of a to-be-polished sapphire board are provided.

  The present invention is based on the knowledge that the polishing composition for a sapphire plate containing abrasive grains and an aqueous medium contains a specific amphoteric surfactant, so that both high-speed polishing and reduction in thickness unevenness can be achieved.

  The polishing liquid composition for sapphire plates of the present invention (hereinafter, “the polishing liquid composition for sapphire plates” may be abbreviated as “polishing liquid composition”) includes abrasive grains A and a specific amphoteric surfactant B. And an aqueous medium. The reason why the polishing composition of the present invention contains the specific amphoteric surfactant B can achieve both high-speed polishing and reduction in thickness unevenness is not clear, but is presumed as follows.

  The specific amphoteric surfactant B contained in the polishing liquid composition of the present invention has a hydrocarbon group and a hydrophilic group having both a negative charge and a positive charge, and the hydrophilic group is adsorbed on the abrasive grains. The hydrocarbon group is adsorbed on the polished sapphire plate by hydrophobic interaction and exhibits a binder effect. As a result, the wettability of abrasive grains to the polished sapphire plate has been improved, the fluidity of the polishing composition on the surface to be polished has been improved, and both high-speed polishing and reduction in thickness unevenness have been made possible. It is guessed. However, the present invention is not limited to these estimations.

[Abrasive A]
The polishing liquid composition of the present invention contains abrasive grains A. As the abrasive grains A, inorganic particles are preferable from the viewpoint of improving the polishing rate. Silica particles, alumina particles, silicon carbide particles, diamond particles, cerium oxide particles, zirconium oxide particles, aluminum oxide particles, manganese oxide particles, boron nitride Examples thereof include one or more particles selected from particles and titanium oxide particles. The abrasive grain A is preferably one or more particles selected from silica particles, alumina particles, silicon oxide particles, and diamond particles, more preferably silica particles and alumina particles, from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. And one or more kinds of particles selected from diamond particles, more preferably silica particles.

  The average secondary particle size of the abrasive grains A is preferably 1 nm or more, more preferably 10 nm or more, still more preferably 50 nm or more, still more preferably 80 nm or more, from the viewpoint of improving the polishing rate, and high-speed polishing and thickness unevenness. From the standpoint of coexistence of reduction, the thickness is preferably 10,000 nm or less, more preferably 1000 nm or less, still more preferably 500 nm or less, and still more preferably 200 nm or less.

  The content of the abrasive grains A in the polishing composition of the present invention is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, from the viewpoint of improving the polishing rate. And from a viewpoint of the cost reduction of a polishing liquid composition, and the improvement of storage stability, Preferably it is 55 mass% or less, More preferably, it is 50 mass% or less, More preferably, it is 45 mass% or less.

(Silica particles)
The average secondary particle size of silica particles (hereinafter also referred to as “silica particles A”) as the preferred abrasive grains A is preferably 10 nm or more, more preferably 50 nm or more, and still more preferably 80 nm or more, from the viewpoint of improving the polishing rate. From the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness, the thickness is preferably 500 nm or less, more preferably 300 nm or less, and even more preferably 200 nm or less. The average secondary particle size can be measured by a dynamic light scattering method, for example, by the method described in the examples.

From the viewpoint of improving the polishing rate, the BET specific surface area of the silica particles A 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, and from the same viewpoint, Preferably it is 200 m < ² > / g or less, More preferably, it is 100 m < ² > / g or less, More preferably, it is 60 m < ² > / g or less. The specific surface area can be measured, for example, by the method described in Examples.

  The average primary particle size of the silica particles A is preferably 500 nm or less, more preferably 300 nm or less, still more preferably 200 nm or less, and even more preferably 150 nm or less, from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. From the viewpoint of improving the polishing rate, the thickness is preferably 45 nm or more, more preferably 70 nm or more. The average primary particle size can be determined, for example, by the method described in Examples described later.

  Examples of the particle shape of the silica particles A contained in the polishing liquid composition of the present invention include spherical and non-spherical silica particles. From the viewpoint of improving the polishing rate, preferably the spherical silica particles and the following irregular shapes are used. From the viewpoint of achieving both a high polishing rate and a reduction in thickness unevenness, spherical silica particles are more preferable. The “spherical silica particles” refer to spherical particles (generally commercially available colloidal silica particles) close to true spheres.

  The average value of the absolute maximum length of the non-spherical silica particles (hereinafter also referred to as “average absolute maximum length”) is preferably 80 nm or more, more preferably 90 nm or more, and still more preferably 100 nm or more, from the viewpoint of improving the polishing rate. Even more preferably 110 nm or more, still more preferably 120 nm or more, and from the same viewpoint, preferably 500 nm or less, more preferably 400 nm or less, still more preferably 300 nm or less, even more preferably 200 nm or less, and even more Preferably it is 150 nm or less. Here, the absolute maximum length refers to the maximum length of the distance between any two points on the outline of the particle projected by electron microscope observation or the like. The average absolute maximum length can be determined by the method described in Examples.

  The average value of the area ratio (a / b × 100) of the non-spherical silica particles is preferably 90% or less from the viewpoint of improving the polishing rate, and preferably 50% or more, more preferably from the same viewpoint. Is 60% or more, more preferably 65% or more, and still more preferably 70% or more. Here, the area ratio (a / b × 100) is obtained by dividing the projected area a of the particle obtained by electron microscope observation by the area b of a circle whose diameter is the absolute maximum length of the particle and multiplying by 100. Value (%). The average value of the area ratio (a / b × 100) can be obtained by the method described in Examples.

  As the non-spherical silica particles, from the viewpoint of improving the polishing rate, preferably, a plurality of precursor particles are aggregated or formed by using silica particles having a particle size smaller than the secondary particle size of the silica particles A as precursor particles. It is a fused shape. From the same viewpoint, the non-spherical silica particles are preferably at least one selected from gold flat sugar-type silica particles Aa, irregular-shaped silica particles Ab, and odd-shaped and gold flat sugar-type silica particles Ac. Ab is more preferred.

  The confetti-type silica particles Aa (hereinafter also referred to as “particles Aa”) are silica particles having unique hook-shaped protrusions on the spherical particle surface. The particle Aa preferably has a shape in which the largest precursor particle a1 and one or more precursor particles a2 having a particle size of 1/5 or less of the precursor particle a1 are aggregated or fused. The particles Aa are preferably in a state in which a plurality of precursor particles a2 having a small particle size are partially embedded in one precursor particle a1 having a large particle size. The particles Aa can be obtained, for example, by the method described in JP 2008-137822 A. The particle diameter of the precursor particles can be obtained as an equivalent circle diameter measured in one precursor particle in an observation image by TEM or the like, that is, the diameter of a circle having the same area as the projected area of the precursor particles. The particle diameters of the precursor particles in the silica particles Ab and the silica particles Ac can be obtained in the same manner.

  The irregular-shaped silica particles Ab (hereinafter also referred to as “particles Ab”) are silica particles having a shape in which two or more precursor particles, preferably two or more and ten or less precursor particles are aggregated or fused. Say. The particle Ab preferably has a shape in which two or more precursor particles having a particle size of 1.5 times or less are aggregated or fused on the basis of the particle size of the smallest precursor particle. The particles Ab can be obtained, for example, by the method described in JP-A-2015-86102.

  The irregular and confetti type silica particles Ac have the particle Ab as a precursor particle c1, the largest precursor particle c1, and one or more precursor particles having a particle size of 1/5 or less of the precursor particle c1. c2 is an aggregated or fused shape.

  Examples of the silica particles A include colloidal silica and fumed silica. Colloidal silica is preferable from the viewpoint of improving the smoothness of a polished object to be polished.

  When the silica particles A are colloidal silica, from the viewpoint of ease of production and economy, a method by particle growth using an alkali silicate aqueous solution as a raw material (hereinafter also referred to as “water glass method”) or a hydrolyzate of alkoxysilane It is preferable that it is obtained by the method of condensation, and it is more preferable that it is obtained by the water glass method. Silica particles obtained by the water glass method can be produced by a conventionally known method. The usage form of the silica particles A is preferably a slurry from the viewpoint of operability.

The silica particles A may be those whose surface is treated with a silane coupling agent or the like, and are preferably silica particles that are not surface-treated from the viewpoint of improving the polishing rate. The silica particles A may contain inorganic elements other than Si, such as Al and Zr. The content of SiO ₂ in the silica particles is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 99% by mass or more in terms of anhydrous oxide from the viewpoint of improving the polishing rate.

When the abrasive grains A contained in the polishing liquid composition of the present invention are silica particles, the content of the silica particles contained in the polishing liquid composition is converted to anhydrous oxide (SiO ₂ ) from the viewpoint of improving the polishing rate. The concentration is preferably 1% by mass or more, more preferably 5% by mass or more, and still more preferably 10% by mass or more, and from the viewpoint of cost reduction and improvement in storage stability of the polishing composition, in terms of SiO ₂ The concentration is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less.

(Alumina particles)
Examples of the alumina particles include α-alumina, intermediate alumina, amorphous alumina, fumed alumina, and the like. Among these, α-alumina is preferable from the viewpoint of improving the polishing rate.

  The average secondary particle size of the alumina particles is preferably 200 nm or more, more preferably 250 nm or more, still more preferably 300 nm or more, and even more preferably 350 nm or more, from the viewpoint of improving the polishing rate, and thickness unevenness can be reduced. From the viewpoint, it is preferably 10,000 nm or less, more preferably 950 nm or less, still more preferably 900 nm or less, and even more preferably 800 nm or less. The average secondary particle diameter can be measured by a dynamic light scattering method, and can be determined by, for example, the method described in Examples.

  The alpha conversion rate of the alumina particles is preferably 50% or more, more preferably 60% or more, from the viewpoint of improving the polishing rate and reducing the number of scratches. The said alpha formation rate can be measured by powder X-ray diffraction, for example, can be measured by the method of an Example.

The BET specific surface area of the alumina particles in the polishing composition of the present invention is preferably 1 m ² / g or more, more preferably 2 m ² / g or more, and further preferably 4 m, from the viewpoint of improving the operational stability of the polishing machine. and ² / g or more, and, from the viewpoint of increasing the polishing rate, preferably 200 meters ² / g or less, more preferably 100 m ² / g or less, still more preferably not more than 60 m ² / g.

  When the abrasive grains A contained in the polishing composition of the present invention are alumina particles, the content of alumina particles contained in the polishing composition is preferably 3% by mass or more from the viewpoint of improving the polishing rate. Preferably, it is 5% by mass or more, more preferably 7% by mass or more, still more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably from the viewpoint of reducing adhesion of abrasive grains to the polishing machine. Is 45% by mass or less, more preferably 40% by mass or less.

(Diamond particles)
Examples of the diamond particles include single crystal diamond particles, single crystal diamond particles obtained by heat-treating single crystal diamond particles, and polycrystalline diamond particles. Among them, polycrystalline diamond particles are preferable from the viewpoint of reducing manufacturing costs. is there.

  The average secondary particle size of the diamond particles is preferably 1 nm or more, more preferably 5 nm or more, further preferably 10 nm or more from the viewpoint of improving the polishing rate, and preferably 1000 nm or less from the viewpoint of reducing thickness unevenness. More preferably, it is 500 nm or less, More preferably, it is 300 nm or less. The average secondary particle diameter of the diamond particles can be determined by the method described in Examples described later.

  When the abrasive grains A contained in the polishing composition of the present invention are diamond particles, the content of diamond particles contained in the polishing composition is preferably 0.01% by mass or more from the viewpoint of improving the polishing rate. More preferably 3% by mass or more, still more preferably 5% by mass or more, still more preferably 10% by mass or more, and from the viewpoint of economy, it is preferably 50% by mass or less, more preferably 45% by mass or less. More preferably, it is 40 mass% or less.

ただし、Ｒ¹及びＲ⁷は、同一又は異なって、炭素数が６以上２４以下の炭化水素基であり、Ｒ⁴は、炭素数が５以上２３以下の炭化水素基であり、Ｒ²，Ｒ³，Ｒ⁵，及びＲ⁶は、同一又は異なって、炭素数が１以上３以下の炭化水素基であり、Ｘは、ＣＨ₂又はＣＯＮＨ(Ｃ_nＨ_2n)であり、Ｙは、Ｃ_mＨ_2mであり、ｎは２以上４以下、ｍは１以上４以下である。 <Amphoteric surfactant B>
The amphoteric surfactant B contained in the polishing composition of the present invention is an amphoteric surfactant B1 represented by the following formula (1) and the following formula (2) from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. It is at least one amphoteric surfactant selected from the group consisting of the amphoteric surfactant B2 represented and the amphoteric surfactant B3 represented by the following formula (3).

R ¹ and R ⁷ are the same or different and are hydrocarbon groups having 6 to 24 carbon atoms, R ⁴ is a hydrocarbon group having 5 to 23 carbon atoms, R ² , R ³ , R ⁵ , and R ⁶ are the same or different and are hydrocarbon groups having 1 to 3 carbon atoms, X is CH ₂ or CONH (C _n H _2n ), and Y is C _m H _2m , n is 2 or more and 4 or less, and m is 1 or more and 4 or less.

The amphoteric surfactant B1 is preferably alkyldimethylamine oxide from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. In the above formula (1), R ¹ is preferably an alkyl group from the same viewpoint. From the same viewpoint, the carbon number of R ¹ is preferably 8 or more, more preferably 10 or more, still more preferably 12 or more, and from the same viewpoint, preferably 18 or less, more preferably 16 or less, Preferably it is 14 or less.

The amphoteric surfactant B2 is preferably at least one selected from alkylbetaines and alkylamidopropylbetaines, more preferably alkylbetaines, from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. In the above formula (2), R ⁴ is preferably an alkyl group from the same viewpoint, and X is preferably CH ₂ from the same viewpoint. The carbon number of R ⁴ is preferably 7 or more, more preferably 9 or more, still more preferably 11 or more from the same viewpoint, and from the same viewpoint, preferably 17 or less, more preferably 15 or less, Preferably it is 13 or less. In the above formula (2), n is preferably 2 or more and 3 or less from the same viewpoint, and m is preferably 1 or more and 3 or less from the same viewpoint.

The amphoteric surfactant B3 is preferably 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. In the above formula (3), R ⁷ is preferably an alkyl group from the same viewpoint. From the same viewpoint, the number of carbon atoms of R ⁷ is preferably 8 or more, more preferably 10 or more, still more preferably 12 or more, and from the same viewpoint, preferably 18 or less, more preferably 16 or less, Preferably it is 14 or less.

  The amphoteric surfactant B is preferably at least one selected from the double-sided surfactants B1 and B2, more preferably the double-sided surfactant B1, from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. From the same viewpoint, the amphoteric surfactant B is preferably a group consisting of alkyldimethylamine oxide, alkyl betaine, alkylamidopropyl betaine, and 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine. And at least one selected from alkyldimethylamine oxide and alkylbetaine, more preferably alkyldimethylamine oxide.

  The content of the amphoteric surfactant B in the polishing composition of the present invention is preferably 0.1 ppm by mass or more, more preferably 0.5 ppm by mass or more, from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. More preferably, it is 1.0 mass ppm or more, and from the same viewpoint, it is preferably 40 mass ppm or less, more preferably 20 mass ppm or less, still more preferably 15 mass ppm or less.

  In the polishing composition of the present invention, the content (unit: part by mass) of the amphoteric surfactant B with respect to 100 parts by mass of the abrasive grains A is preferably 0.025 or less, from the viewpoint of reducing thickness unevenness. Preferably it is 0.010 or less, more preferably 0.005 or less, and from the viewpoint of improving the polishing rate, it is preferably 0.00025 or more, more preferably 0.0005 or more, still more preferably 0.001 or more. .

[Aqueous medium]
Examples of the aqueous medium contained in the polishing liquid composition of the present invention include water such as ion-exchanged water and ultrapure water, or a mixed medium of water and a solvent. The solvent is a solvent that can be mixed with water. (For example, alcohol such as ethanol) is preferred. As the aqueous medium, ion-exchanged water or ultrapure water is more preferable, and ultrapure water is more preferable. When the aqueous medium is a mixed medium of water and a solvent, the ratio of water to the entire mixed medium is not particularly limited, but is preferably 95% by mass or more, and 98% by mass from the viewpoint of economy. The above is more preferable, substantially 100% by mass is still more preferable, and 100% by mass is even more preferable.

  The content of the aqueous medium in the polishing composition of the present invention is not particularly limited, and may be the abrasive grains A, the amphoteric surfactant B, and the remainder of the optional components described below.

  The pH at 25 ° C. of the polishing composition of the present invention is preferably 7 or more, more preferably 9 or more, still more preferably 10 or more, and the abrasive grains are silica particles from the viewpoint of improving the polishing rate. From the viewpoint of suppressing the dissolution of the silica particles and improving the storage stability of the polishing composition, it is preferably 12 or less.

  The polishing composition of the present invention may further contain conventionally known optional components depending on the intended use. When the polishing liquid composition of the present invention is, for example, a polishing liquid composition for sapphire substrates for electronic components such as semiconductor elements (for example, a polishing liquid composition for sapphire substrates for LEDs), the polishing liquid composition of the present invention. May further contain a compound having a sugar skeleton, a pH adjuster (acid, alkali), an oxidizing agent, a rust inhibitor, an antibacterial agent, an antistatic agent, an inorganic phosphate compound described later, and the like. Specific examples of the compound having a sugar skeleton, the pH adjuster (acid, alkali), and the oxidant include those described in JP-A-2015-227446.

[Inorganic phosphate compounds]
The polishing composition of the present invention preferably contains an inorganic phosphate compound from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. The inorganic phosphate compound includes at least one inorganic phosphate selected from the group consisting of orthophosphate, phosphite, and hypophosphite from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. Compounds are preferred, and orthophosphates and phosphites are more preferred. The inorganic phosphate compound is preferably an alkali metal salt, an alkaline earth metal salt, or an ammonium salt. As the alkali metal or alkaline earth metal, magnesium, calcium, sodium, and potassium are preferable. Among these, from the viewpoint of suppressing the aggregation of abrasive grains, the inorganic phosphate compound is more preferably at least one selected from sodium salts, potassium salts, and ammonium salts.

Specific examples of the inorganic phosphate compound include sodium phosphate (Na ₃ PO ₄ ), potassium phosphate (K ₃ PO ₄ ), and disodium monohydrogen phosphate from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. (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 ), phosphoric acid Orthophosphate such as dipotassium monohydrogen (K ₂ HPO ₄ ), diammonium monohydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ); sodium phosphite (Na ₂ HPO ₃ ), potassium phosphite (K ₂ Phosphites such as HPO ₃ ); sodium hypophosphite (NaH ₂ PO ₂ ), potassium hypophosphite (KH ₂ PO ₂ ), ammonium hypophosphite (NH ₄ H ₂ PO ₂ ) and the like Phosphites and these Among them, from the viewpoint of reduction in the level of high-speed polishing and thickness unevenness, disodium hydrogen phosphate, potassium monohydrogen phosphate, disodium phosphite, sodium hypophosphite, monohydrogen phosphate diammonium ((NH ₄ ) One or more inorganic phosphate compounds selected from the group consisting of ₂ HPO ₄ ) and ammonium hypophosphite are preferred. These inorganic salts may have a hydrate structure.

  The content of the inorganic phosphate compound contained in the polishing liquid composition of the present invention is preferably 1 ppm by mass or more, more preferably 10 ppm by mass or more, and still more preferably from the viewpoint of achieving both high-speed polishing and reduction in thickness unevenness. Is 100 ppm by mass or more, still more preferably 200 ppm by mass or more, still more preferably 500 ppm by mass or more, and even more preferably 800 ppm or more, and from the viewpoint of reducing the thickness unevenness of the polished object to be polished, Preferably it is 5000 mass ppm or less, More preferably, it is 4000 mass ppm or less, More preferably, it is 3000 mass ppm or less, More preferably, it is 2000 mass ppm or less.

  In the polishing composition of the present invention, the content ratio between the abrasive grains A and the inorganic phosphate compound [the content of abrasive grains A (mass ppm) / the content of inorganic phosphate compounds (mass ppm)] is From the viewpoint of reducing thickness unevenness, it is preferably 2 or more, more preferably 20 or more, still more preferably 100 or more, and from the same viewpoint, preferably 10,000 or less, more preferably 4000 or less, and still more preferably 1000 or less. is there.

[Method for preparing polishing liquid composition]
The polishing liquid composition of this invention can be prepared by mixing each component by a well-known method. The polishing composition is usually produced as a concentrated solution from the viewpoint of economy, and it is often diluted at the time of use. The polishing composition may be used as it is, or diluted if it is a concentrated solution. When diluting the concentrate, the dilution factor 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 for producing a sapphire plate of the present invention using the polishing liquid composition of the present invention (hereinafter sometimes abbreviated as “an example of a method of production of the present invention”) and the coating of the present invention. An example of the polishing method for the polished sapphire plate (hereinafter, also referred to as “an example of the polishing method of the present invention” in some cases) will be described.

[To be polished]
An example of the manufacturing method of the present invention and an object to be polished in the example of the polishing method of the present invention are nonpolar surfaces (A surface, etc.), semipolar surfaces (M surface, R surface, etc.) of the sapphire plate, and Any of the polar surfaces (C surface and the like) may be used, and the polar surface (C surface) is preferable from the viewpoint of more prominently achieving the effects of the present invention. The shape of the object to be polished may be a shape having a curved surface portion such as a lens as well as a shape having a flat portion such as a disk shape, a plate shape, a slab shape, or a prism shape. Moreover, the said to-be-polished object is various, such as a sapphire board used as a cover glass of portable terminal devices, such as a smart phone, and a sapphire substrate for LED, The polishing liquid composition of this invention is portable, such as a sapphire substrate for LED, a smart phone. It is suitable as a polishing composition used in the polishing step of the method for producing a sapphire plate used as a cover glass for a 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 plate for a cover glass of a mobile terminal device such as a sapphire substrate for LED or a smartphone, and the polishing liquid composition of the present invention is used. And a step of polishing the polished sapphire plate. Moreover, an example of the polishing method of the to-be-polished sapphire plate of the present invention is a polishing method of a sapphire plate such as a sapphire plate for a cover glass of a mobile terminal device such as a sapphire substrate for LED or a smartphone, and the polishing liquid composition of the present invention The process of grind | polishing a to-be-polished sapphire board using a thing is included.

  The step of polishing the sapphire plate to be polished includes a first polishing step (rough polishing step) for planarizing a wafer obtained by slicing a sapphire single crystal ingot into a thin disc shape, and after etching the rough polished wafer The polishing liquid composition of the present invention can be used in both 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 common to use a polishing composition containing diamond as abrasive grains.

  As an example of the manufacturing method of the present invention and a polishing apparatus used in an example of the polishing method of the present invention, for example, a jig (carrier: glass epoxy material or the like) that holds the polished sapphire plate and a polishing cloth (polishing pad) An equipped polishing apparatus can be used, and either a double-side polishing apparatus or a single-side polishing apparatus may be used.

  A conventionally well-known thing can be used for the said polishing pad. Examples of the material for the polishing pad include organic polymers, and examples of the organic polymer include polyurethane. The shape of the polishing pad is preferably a nonwoven fabric. For example, SUBA800 (manufactured by Nitta Haas) is suitably used as the nonwoven fabric polishing pad.

  In one example of the production method of the present invention and one example of the polishing method of the present invention, the sapphire plate to be polished is sandwiched between polishing sapphire plates held by a carrier and a polishing pad attached thereto, and the polishing composition of the present invention Is supplied between the polishing pad and the polished sapphire plate, and the polished sapphire plate is polished by moving the polishing pad and / or the polished sapphire plate while contacting the polished sapphire plate and the polishing pad. Process.

The polishing load in one example of the production method and one example of the polishing method of the present invention is preferably 50 g / cm ² or more, more preferably 100 g / cm ² or more, further preferably 150 g / cm ² or more, from the viewpoint of improving the polishing rate. Even more preferably, it is 200 g / cm ² or more, and considering the durability of the device, pad, etc., it is preferably 400 g / cm ² or less, more preferably 350 g / cm ² or less. The polishing load can be adjusted by applying air pressure or weight to the surface plate or the polished sapphire plate. The polishing load means the pressure of the surface plate applied to the polishing surface of the polished sapphire plate during polishing.

  The method of supplying the polishing liquid composition of the present invention is a method of supplying a polishing pad between a polishing pad and a sapphire plate to be polished by a pump or the like in a state where the constituents of the polishing liquid composition are sufficiently mixed in advance. And the like. A method of supplying a polishing liquid composition between a polishing pad and a sapphire plate to be polished with a pump or the like in a state where constituents of the polishing liquid composition are sufficiently mixed in advance from the viewpoint of improving the polishing rate and reducing the load on the apparatus Is preferred.

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

  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, both high-speed polishing and reduction in thickness unevenness can be achieved.

  In another example of the production method of the present invention, a polishing liquid composition of the present invention is supplied to a polished sapphire plate to polish the polished sapphire plate, and the polishing liquid composition used in the step And polishing a polished sapphire plate different from the polished sapphire plate using an object.

  Examples 1-16, Comparative Example 1 using abrasive grains A, amphoteric surfactant B or its comparison object, ion-exchanged water, pH adjuster, and inorganic phosphate compound as required -8 polishing liquid compositions were prepared. In the polishing composition of Examples 1 to 16 and Comparative Examples 1 to 8, the contents of the abrasive grains, the amphoteric surfactant B or its comparison object, and the inorganic phosphate compound are as shown in Table 1, respectively. It was. The addition amount of the pH adjuster was set so that the pH at 25 ° C. of the polishing composition of Examples 1 to 16 and Comparative Examples 1 to 8 was the value shown in Table 1. The content of ion-exchanged water in the polishing liquid composition is the remaining amount excluding the abrasive grains, the amphoteric surfactant B or its comparison object, the pH adjuster, and the inorganic phosphate compound.

<Examples 1-4>
After adding the betaine-type amphoteric surfactants listed in Table 1 into a beaker containing ion-exchanged water, spherical colloidal silica particles (BET specific surface area: 31.7 m ² / g) and an aqueous dispersion are added. Were added to obtain an aqueous dispersion containing additive-added spherical colloidal silica particles. Immediately thereafter, the pH of the additive-added spherical colloidal silica particle aqueous dispersion was adjusted to 9.6 using a 48 mass% aqueous sodium hydroxide solution (manufactured by Kanto Chemical Co., Inc.) as a pH adjuster, and Examples 1-4 A polishing liquid composition was obtained.

<Example 5>
A polishing liquid composition of Example 5 was prepared in the same manner as in Example 1 except that the amine oxide type amphoteric surfactant B was used in place of the betaine type amphoteric surfactant B.

<Examples 6 to 9>
The polishing composition of Examples 6-9 was prepared like Example 5 except having changed content of an amine oxide type amphoteric surfactant.

<Example 10>
Furthermore, a polishing composition of Example 10 was prepared in the same manner as Example 5 except that sodium phosphite was added.

<Example 11>
A polishing liquid composition of Example 11 was prepared in the same manner as in Example 5 except that the addition amount of a 48 mass% sodium hydroxide aqueous solution (manufactured by Kanto Chemical Co., Inc.) was changed to pH 8.0.

<Example 12>
A polishing liquid composition of Example 12 was prepared in the same manner as Example 5 except that the addition amount of 48 mass% sodium hydroxide aqueous solution (manufactured by Kanto Chemical Co., Inc.) was changed to 11.5.

<Example 13>
The same polishing liquid composition as in Example 5 was prepared as a polishing liquid composition for polishing the A surface.

<Example 14>
Example 14 was carried out in the same manner as in Example 5 except that α-alumina particles (abrasive grains, α conversion 90%, crystallite size 32 nm) were used in place of the spherical colloidal silica particle aqueous dispersion. A polishing liquid composition was prepared.

<Example 15>
Instead of using the spherical silica particle aqueous dispersion, the modified silica particle Ab (shown as “irregular silica” in Table 1; BET specific surface area: 34.2 m ² / g) was used except that an aqueous dispersion was used. The polishing composition of Example 15 was prepared in the same manner as Example 5. The non-spherical silica particles Ab have an average absolute maximum length of 122.6 nm and an average area ratio (a / b × 100) of 72.8%.

<Example 16>
A polishing composition of Example 16 was prepared in the same manner as in Example 5 except that the aqueous dispersion of diamond particles was used instead of the aqueous dispersion of spherical silica particles.

<Comparative Example 1>
A polishing liquid composition of Comparative Example 1 was prepared in the same manner as in Example 1 except that the amphoteric surfactant was not added.

<Comparative example 2>
A polishing liquid composition of Comparative Example 2 was prepared in the same manner as in Example 1 except that linear alkylbenzenesulfonic acid was added instead of the betaine type amphoteric surfactant.

<Comparative Example 3>
A polishing liquid composition of Comparative Example 3 was prepared in the same manner as Comparative Example 1 except that the addition amount of a 48 mass% sodium hydroxide aqueous solution (manufactured by Kanto Chemical Co., Inc.) was changed to pH 8.0.

<Comparative Example 4>
A polishing liquid composition of Comparative Example 4 was prepared in the same manner as Comparative Example 1 except that the addition amount of a 48 mass% sodium hydroxide aqueous solution (manufactured by Kanto Chemical Co., Inc.) was changed to pH 11.5.

<Comparative Example 5>
The same polishing liquid composition as that of Comparative Example 2 was prepared as a polishing liquid composition for polishing the A surface.

<Comparative Example 6>
A polishing liquid composition of Comparative Example 6 was prepared in the same manner as in Example 1 except that sodium polystyrene sulfonate was added instead of the betaine-type amphoteric surfactant.

<Comparative Example 7>
A polishing composition of Comparative Example 7 was prepared in the same manner as in Example 1 except that polyvinyl alcohol was added instead of the betaine-type amphoteric surfactant.

<Comparative Example 8>
A polishing liquid composition of Comparative Example 8 was prepared in the same manner as in Example 1 except that perfluoroalkylamine oxide was added instead of the betaine-type amphoteric surfactant.

2. Measurement method of various parameters [Measurement of average primary particle size of abrasive grains]
The average primary particle size (nm) of the abrasive grains was calculated by the following formula using the specific surface area S (m ² / g) calculated by the BET (nitrogen adsorption) method.
Average primary particle size (nm) = 2727 / S = 6 / (ρ × S)
ρ: Material density (kg / m ³ )

  The specific surface area of the abrasive grains is subjected to the following [pretreatment], and then approximately 0.1 g of a measurement sample is precisely weighed to 4 digits after the decimal point in a measurement cell, and immediately under the measurement at 110 ° C. for 30 minutes immediately before the measurement of the specific surface area. After drying, the surface area was measured by a nitrogen adsorption method (BET method) using a specific surface area measuring device (Micromeritic automatic specific surface area measuring device Flowsorb III 2305, manufactured by Shimadzu Corporation).

[Preprocessing]
(A) The slurry containing abrasive grains is adjusted to pH 2.5 ± 0.1 with an aqueous nitric acid solution.
(B) The slurry is taken in a petri dish and dried in a hot air dryer at 150 ° C. for 1 hour.
(C) After drying, the obtained sample is finely ground in an agate mortar.
(D) The pulverized sample is suspended in ion exchange water at 40 ° C. and filtered through a membrane filter having a pore size of 1 μm.
(E) The filtrate on the filter is washed 5 times with 20 g of ion exchange water (40 ° C.).
(F) The filter with the filtrate attached is taken in a petri dish and dried in an atmosphere of 110 ° C. for 4 hours.
(G) The dried filtrate (abrasive grains) was taken so as not to be mixed with filter waste, and finely pulverized with a mortar to obtain a measurement sample.

[Measurement of average secondary particle size of abrasive grains]
The average secondary particle size (dispersed particle size) of the abrasive grains is measured under the following conditions using a dynamic light scattering (DLS) particle size distribution meter (manufactured by Malvern, Zetasizer Nano S). The particle size (D50) was determined as the average secondary particle size (dispersed particle size).
Solvent: water (refractive index 1.333)
Abrasive grains: colloidal silica particles (refractive index 1.45, attenuation coefficient 0.02)
Measurement temperature: 25 ° C

[Average value of average absolute maximum length and area ratio (a / b × 100) of abrasive grains]
A photograph obtained by observing the abrasive grains with a transmission electron microscope (TEM) manufactured by JEOL (trade name “JEM-2000FX”, 80 kV, 1 to 50,000 times) is captured as image data with a scanner on a personal computer, and analysis software “WinROOF (Ver. .3.6) "(distributor: Mitani Corporation), the projection area a and the absolute maximum length of each abrasive grain were determined for 1000 to 2000 abrasive grain data. The average absolute maximum length was defined as the average absolute maximum length. The area of a circle whose diameter is the absolute maximum length of each abrasive grain is b, the area ratio (a / b × 100) (%) is calculated, and the average value is the average of the area ratio (a / b × 100). Value.

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

3. Evaluation [Evaluation of polishing rate]
The sapphire plate was subjected to cyclic polishing for 3 hours using the polishing composition under the following polishing conditions. And the weight change before and behind grinding | polishing of a sapphire board was calculated | required, and polishing rate (micrometer / h) was computed from the sapphire density (3.98g / cm < ³ >) and the sapphire board area. The area of the polished surface of the sapphire plate, for C face for 45.6cm ^2, A plane was set to 20.3 cm ^2. The polishing rate when the polishing liquid compositions of Examples 1 to 16 and Comparative Examples 1 to 8 are used is a relative value when the polishing rate when the polishing liquid composition of Comparative Example 1 is used is “100”. The results are shown in Table 1.

(Polishing conditions)
Single-side polishing machine (TR15M-TRK1, made by Technolize, platen diameter 38cm)
Nonwoven polishing pad (Nitta Haas SUBA800)
Polishing load 300g / cm ²
Plate rotation speed 120rpm
Carrier rotation speed 120rpm
Polishing fluid flow rate: C surface polishing 120mL / min (circulation)
A side polishing 120mL / min (circulation)
After polishing the sapphire plate under the above polishing conditions, the sapphire plate was immersed in ultrapure water, and then washed with running water (ultrapure water) and dried.

[TTV (Total Thickness Value) measurement method]
After polishing the sapphire plate using the polishing composition, it is immersed in ultrapure water, then rinsed with running water (ultra pure water) and dried,
With a Digimatic Micrometer (MDH-25M manufactured by Mitutoyo Corporation) under the conditions of one point at the center of the substrate and five points at the outer periphery of the substrate (position 0.5 mm from the end of the substrate). The TTV was determined by taking the difference of the average value of the substrate thickness at five points on the outer periphery of the substrate from the substrate thickness value at the center of the substrate. TTV when using the polishing liquid compositions of Examples 1 to 16 and Comparative Examples 1 to 8 is a relative value when TTV when using the polishing liquid composition of Comparative Example 1 is “100”. It is shown in Table 1.

  As shown in Table 1, when the polishing liquid composition of the example is used, both high-speed polishing and reduction in thickness unevenness can be performed better than when the comparative polishing liquid composition is used.

  As explained above, in polishing of a polished sapphire plate using the polishing composition of the present invention, both high-speed polishing and reduction in thickness unevenness can be achieved. Therefore, if the polishing liquid composition of this invention is used, productivity, such as a sapphire board used for manufacture of cover glass of portable terminal devices, such as manufacture of LED and a smart phone, will improve, for example.

Claims (9)

Abrasive grains A;
At least one amphoteric surfactant selected from amphoteric surfactant B1 represented by the following formula (1), amphoteric surfactant B2 represented by the following formula (2), and amphoteric surfactant B3 represented by the following formula (3) Surfactant B,
A polishing liquid composition for a sapphire plate containing an aqueous medium.

R ¹ and R ⁷ are the same or different and are hydrocarbon groups having 6 to 24 carbon atoms, R ⁴ is a hydrocarbon group having 5 to 23 carbon atoms, R ² , R ³ , R ⁵ , and R ⁶ are the same or different and are hydrocarbon groups having 1 to 3 carbon atoms, X is CH ₂ or CONH (C _n H _2n ), and Y is C _m H _2m , n is 2 or more and 4 or less, and m is 1 or more and 4 or less.   The polishing liquid composition according to claim 1, wherein the abrasive grains A are silica particles.   The polishing composition according to claim 1 or 2, further comprising one or more inorganic phosphate compounds selected from the group consisting of orthophosphate, phosphite, and hypophosphite.   The polishing liquid composition according to any one of claims 1 to 3, wherein the inorganic phosphate compound is one or more of an alkali metal salt, an alkaline earth metal salt, and an ammonium salt. .   In the said polishing liquid composition, content of the said amphoteric surfactant B with respect to 100 mass parts of said abrasive grains A is 0.00025 or more and 0.025 or less, It is any one of Claim 1 to 4 characterized by the above-mentioned. The polishing liquid composition as described.   The polishing composition according to any one of claims 1 to 6, wherein the polishing composition has a pH of 7 or more and 12 or less at 25 ° C.   The manufacturing method of a sapphire board including the process of supplying the polishing liquid composition as described in any one of Claims 1-6 with respect to a to-be-polished sapphire board, and grind | polishing the said to-be-polished sapphire board.   The polishing liquid composition according to any one of claims 1 to 6 is supplied to a polished sapphire plate, the step of polishing the polished sapphire plate, and the polishing liquid composition used in the step Polishing a sapphire plate to be polished, which is different from the sapphire plate to be polished, using an object.   A polishing method for a polished sapphire plate, comprising a step of supplying the polishing liquid composition according to any one of claims 1 to 6 to the polished sapphire plate and polishing the polished sapphire plate.