JP2011040427A - Abrasive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abrasive composition with which a hard substrate can be polished at a high polishing speed. <P>SOLUTION: The abrasive composition contains abrasive grains of polycrystalline diamond and/or single-crystal diamond of 0.1 to 15 μm in average particle size, and an aqueous dispersion medium containing polyhydric alcohol and water, and has a viscosity of 2.0 to 100 mPa s. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an abrasive composition. More specifically, the present invention relates to an abrasive composition useful for efficiently polishing a hard substrate having a semiconductor crystal film.

  Semiconductor parts, optical parts, magnetic disks, and the like are subjected to polishing by fixed abrasive polishing or loose abrasive polishing.

  In loose abrasive polishing, an abrasive composition is supplied between a metal surface plate and a surface to be polished, and the surface plate is rotated while pressing the abrasive particles against the surface to be polished. At this time, the abrasive composition used for polishing free abrasive grains is obtained by dispersing various particles such as diamond, alumina, silica, zirconia as abrasive grains in a dispersion medium.

  The abrasive composition used for polishing the free abrasive grains of a hard substrate made of sapphire, zinc oxide, spinel, group III nitride, silicon carbide, etc. includes, for example, artificial diamond abrasive grains disclosed in Patent Document 1. There is an oily polishing slurry to contain.

JP 2008-138097 A

  However, conventionally known abrasive compositions including the oil-based polishing slurry described in Patent Document 1 cannot be used to polish free abrasive grains at a sufficiently high polishing rate on a hard substrate.

  In view of the above problems, an object of the present invention is to provide an abrasive composition capable of polishing a hard substrate at a high polishing rate.

  In order to solve the above-mentioned problems, the present inventors have intensively studied the polyhydric alcohol and abrasive grains contained in the abrasive composition, and as a result, completed the present invention. That is, according to the present invention, the following abrasive composition is provided.

[1] A monocrystalline diamond and / or polycrystalline diamond abrasive having an average particle size of 0.1 to 15 μm, an aqueous dispersion medium containing a polyhydric alcohol and water, and a viscosity of 2.0 to 100 mPa An abrasive composition that is s.

[2] The abrasive composition according to [1], wherein 30 to 90% by mass of the polyhydric alcohol is contained in the total amount.

[3] The abrasive according to [1] or [2], wherein the polyhydric alcohol is at least one selected from the group consisting of compounds having a structure represented by the following chemical formula (I) or (II). Composition.

HO— (CHR ¹ ) _n —R ² (I)

(In the chemical formula (I), n is a natural number of ¹ to 6. R ¹ represents H or OH, and n R ^{1 s} may be the same or different. R ² represents H or OH. Provided that at least one of n R ¹ and R ² is OH.)

HO — ((CHR ³ ) _m —O) _n —H (II)

(In the chemical formula (II), m is 2 or 3, and n is 2 or 3. R ³ represents H, OH, or CH ₃ , and m R ³ may be the same or different. Good.)

[4] The abrasive composition according to [3], wherein the polyhydric alcohol includes at least one selected from the group consisting of glycerin, diglycerol, and ethylene glycol.

[5] The abrasive composition according to any one of [1] to [4], wherein the pH is 3 to 12.

[6] The polishing agent according to any one of [1] to [5], which is used when polishing a hard substrate made of at least one of sapphire, zinc oxide, spinel, group III nitride, and silicon carbide. Composition.

  The abrasive composition of the present invention is a surface to be polished in which the diamond abrasive grains are uniformly dispersed and the diamond abrasive grains are uniformly dispersed even during polishing and the supply amount per unit time is substantially constant. And can be polished at a high polishing rate. Furthermore, the polishing composition of the present invention can polish a hard substrate made of at least one of sapphire, zinc oxide, spinel, group III nitride, and silicon carbide at a high polishing rate.

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

1. Abrasive composition:
1-1. Summary of the abrasive composition of the present invention:
The abrasive composition of the present invention contains diamond abrasive grains having an average particle size of 0.1 to 15 μm, an aqueous dispersion medium containing a polyhydric alcohol and water, and has a viscosity of 2.0 to 100 mPa · s. It is characterized by that.

  For the abrasive grains of diamond contained in the abrasive composition of the present invention, only single crystal diamond, only polycrystalline diamond, or both polycrystalline diamond and single crystal diamond may be used. From the viewpoint of improving the polishing rate, it is preferable to use polycrystalline diamond as the abrasive contained in the abrasive composition of the present invention rather than single crystal diamond.

  In the abrasive | polishing agent composition of this invention, the average particle diameter of the abrasive grain of a single crystal and a polycrystalline diamond is 0.1-15 micrometers. As a result, it is possible to maintain a polishing rate equal to or higher than a certain rate that meets practical use, to prevent generation of scratches and scratches on the surface to be polished, and to reduce the surface roughness of the surface to be polished.

  Furthermore, from the viewpoint of reliably realizing a high polishing rate, the average particle diameter of single crystal and polycrystalline diamond abrasive grains is preferably 1.0 μm or more, and prevention of generation of scratches and scratches on the surface to be polished, From the viewpoint of ensuring the reduction of the surface roughness, the average grain size of the single crystal and polycrystalline diamond abrasive grains is preferably 10 μm or less.

  In addition, the average particle diameter of the diamond abrasive grain here is a median diameter measured by a laser diffraction method.

  The content of diamond abrasive grains in the abrasive composition of the present invention is not particularly limited as long as the viscosity of the abrasive composition is 2.0 to 100 mPa · s.

  The content of diamond abrasive grains in the abrasive composition of the present invention is preferably 0.01 to 10% by mass in the total amount from the viewpoint of improving the polishing rate by increasing the dispersibility of the abrasive grains. From the viewpoint of reliably realizing polishing at the polishing rate, 0.1 to 5% by mass is more preferable. The numerical ranges of these contents correspond to both single crystal diamond and polycrystalline diamond.

  In the abrasive composition of the present invention, one compound or two or more compounds may be contained as the polyhydric alcohol. The type and concentration of the polyhydric alcohol are not limited as long as the viscosity of the abrasive composition is 2.0 to 100 mPa · s.

  Examples of the water contained in the abrasive composition of the present invention include distilled water and ion exchange water.

  The viscosity here is measured at a temperature of 25 ° C. of the abrasive composition in a viscosity measuring method using a single cylindrical rotational viscometer defined in JIS standard Z8803 (last revised date: August 1, 1991). Shall be.

  In the abrasive composition of the present invention, the abrasive grains of diamond are uniformly dispersed by setting the viscosity to 2.0 to 100 mPa · s. For example, in a usage mode in which the abrasive composition of the present invention is stored in a container or the like, and the abrasive composition is sprayed from the container using a nozzle or the like and supplied to the surface to be polished, the abrasive composition of the present invention is Since it has an appropriate viscosity as described above, it is supplied to the surface to be polished through a nozzle or the like while maintaining a uniformly dispersed state of diamond abrasive grains. That is, in the case of supplying the polishing composition of the present invention to the surface to be polished continuously or intermittently within a predetermined polishing time, the polishing composition that reaches the surface to be polished at any time within the polishing time. The concentration of diamond abrasive grains is substantially constant, and diamond abrasive grains are distributed almost evenly over the entire surface to be polished at any time. For this reason, the abrasive composition of the present invention can be reproducibly polished at a high polishing rate.

  The abrasive | polishing agent composition of this invention can also be set as embodiment described in detail below, providing the characteristic described above.

1-2. Polyhydric alcohol:
In the abrasive | polishing agent composition of this invention, when polyhydric alcohol is contained in 30-90 mass% in the whole quantity, it is preferable. As a result, the uniform dispersibility of the diamond abrasive grains in the above-described abrasive composition and the stability of the abrasive composition on the surface to be polished while maintaining the uniformly dispersed state of the diamond abrasive grains are maintained. More reliable supply, and thus stable polishing at a high polishing rate can be ensured. In order to further enhance such effects, it is more preferable that the abrasive composition of the present invention contains 40 to 80% by mass of polyhydric alcohol in the total amount.

  In the abrasive composition of the present invention, the polyhydric alcohol is a compound having a linear alkylene skeleton, or a compound having a linear alkylene skeleton having one or more ether bonds in the molecule. It is preferable that the chain has two or more hydroxyl groups, and the hydroxyl group of the side chain of the linear alkylene skeleton is directly bonded to the linear alkylene group.

  Among the polyhydric alcohols described above, the polyhydric alcohol contained in the polishing composition of the present invention is represented by the following chemical formula (I) or (II) and is a compound having two or more hydroxyl groups in the molecule. More preferably, it is at least one selected from the group consisting of:

HO— (CHR ¹ ) _n —R ² (I)

(In the chemical formula (I), n is a natural number of ¹ to 6. R ¹ represents H or OH, and n R ^{1 s} may be the same or different. R ² represents H or OH. Provided that at least one of n R ¹ and R ² is OH.)

HO — ((CHR ³ ) _m —O) _n —H (II)

(In the chemical formula (II), m is 2 or 3, and n is 2 or 3. R ³ represents H, OH, or CH ₃ , and m R ³ may be the same or different. Good.)

  Specific examples of the compound having a structure represented by the above chemical formula (I) contained as a polyhydric alcohol in the abrasive composition of the present invention include ethylene glycol, 1,2-propanediol, 1,3- Examples include propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and glycerin.

  Specific examples of the compound having the structure represented by the chemical formula (II) include diglycerol, dihydroxydiethyl ether, 2,2′-ethylenedioxybis (ethanol), dipropylene glycol, tripropylene glycol and the like. be able to.

  When the polishing composition of the present invention contains a compound having the structure represented by the above chemical formula (I) or (II) as a polyhydric alcohol, the physical repulsive force between the diamond abrasive grains and the polishing surface plate during polishing. Is kept low, and the diamond abrasive grains are held in a state of being adhered to the polishing surface plate, so that polishing can be performed at a higher polishing rate.

  Although the mechanism of action that produces such an effect is not exactly clear, the following states arise from the chemical properties common to the compounds having the structure represented by the chemical formula (I) or (II). It is assumed that When the abrasive composition of the present invention contains the above compound, the hydrophobic portion of the fatty chain of the compound is adsorbed on the surface of the diamond abrasive grains, and the compound is exposed to a hydroxyl group having a high degree of hydrophilicity on the outside. It tends to be in a state of enveloping diamond abrasive grains. Therefore, when the diamond abrasive grains are coated on the surface, the hydrophilicity of the surface is increased, and the physical repulsive force between the diamond abrasive grains and the polishing surface plate is low as described above. It is thought that it is restrained.

  In particular, among the compounds having the structure represented by the chemical formula (I) or (II), glycerin has a particularly high physical adsorptive power between the fat chain which is a hydrophobic group and the surface of the diamond abrasive grain. In the state where all the three hydroxyl groups are exposed to the outside, the glycerin is easy to wear, and the physical repulsive force between the diamond abrasive grains and the polishing surface plate is further reduced.

  Therefore, in the abrasive | polishing agent composition of this invention, it is further more preferable to contain glycerin as a polyhydric alcohol, and it is much more preferable when glycerin is included in 50-70 mass% in the whole quantity in an abrasive | polishing agent composition from a viewpoint which can improve a polishing rate. preferable.

  Moreover, when only 1 type of glycerol is contained as a polyhydric alcohol, it is preferable that the density | concentration of glycerol is 50-70 mass%.

1-3. pH:
In the abrasive composition of the present invention, agglomeration and sedimentation of diamond abrasive grains occurs in a strongly acidic region of less than pH 3 and a strongly alkaline region of more than pH 12, so that the pH is preferably 3-12. Furthermore, the pH is preferably 4 to 11, and more preferably 5 to 10. In order to adjust the pH within such a numerical range, a pH adjuster may be added to the abrasive composition of the present invention.

  The pH adjuster for adjusting the pH to the alkaline side is not particularly limited, but examples of the pH adjuster for the inorganic alkali component include ammonium compounds, alkali metal compounds, alkaline earth metal compounds, and the like. Examples of the pH adjuster for the organic alkali component include organic amine compounds. Specifically, sodium compounds such as ammonia, ammonium carbonate, sodium hydroxide, sodium carbonate, sodium phosphate, sodium borate, potassium compounds such as potassium hydroxide, potassium carbonate, potassium phosphate, potassium borate, etc. Can be mentioned. Organic amine compounds include methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, amylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, trimethylamine, triethylamine. , Tributylamine, ethanolamine, propanolamine, butanolamine, diethanolamine, dipropanolamine, dibutanolamine, triethanolamine, tripropanolamine, tributanolamine, ethylenediamine and the like. Of these, inorganic alkali components are preferred in view of cost and environmental impact, and sodium hydroxide and potassium hydroxide are particularly preferred.

  The pH adjuster that adjusts the pH to the acidic side is not particularly limited, but for example, an organic acid component is preferable, specifically, malic acid, maleic acid, lactic acid, succinic acid, acetic acid, citric acid, Examples include succinic acid, malonic acid, glycolic acid, adipic acid, ascorbic acid, itaconic acid, iminodiacetic acid, glyoxylic acid, formic acid, acrylic acid, crotonic acid, nicotinic acid, citraconic acid, tartaric acid and the like.

1-4. Workpiece:
The abrasive composition of the present invention can be used for polishing a hard substrate having a semiconductor crystal film. In particular, the abrasive composition of the present invention is higher in hard substrate composed of at least one of sapphire, zinc oxide, spinel, group III nitride, and silicon carbide than conventionally known abrasive compositions for hard substrates. It can be effectively polished at the polishing rate. Examples of the group III nitride include gallium nitride, indium gallium nitride, aluminum gallium nitride, aluminum indium gallium nitride, aluminum nitride, and indium nitride.

  In addition, in the abrasive | polishing agent composition of this invention, you may contain surfactant and another additive according to various requirements, such as grinding | polishing conditions, a to-be-polished object, or the state of a grinding | polishing surface.

  Examples of the surfactant that can be contained in the abrasive composition of the present invention include anionic surfactants, nonionic surfactants, and cationic surfactants, and anionic surfactants. Examples thereof include compounds having carboxylic acid, sulfonic acid, phosphoric acid or salts thereof. Nonionic surfactants include compounds having oxyethylene group or oxypropylene group, and cationic surface activity. Examples of the agent include compounds having tetraalkylammonium or a salt thereof. These surfactants may be used alone or in combination of two or more.

  Other additives that can be contained in the abrasive composition of the present invention include corrosion inhibitors, antifreeze agents, oxidizing agents, chelating agents, and the like.

2. Manufacturing method of abrasive composition:
The abrasive composition of the present invention can be prepared by mixing diamond, water, polyhydric alcohol, and, if necessary, other components such as the above additives by a known method. For specific examples of the method for producing the abrasive composition of the present invention, refer to the following examples.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

(Examples 1-14, Comparative Examples 1-5)
In the composition shown in Table 1, an abrasive composition containing diamond abrasive grains and an aqueous dispersion medium was obtained. Below, an abrasive grain, an aqueous dispersion medium, and mixing stirring are demonstrated in detail first, Then, the evaluation test of the obtained abrasive | polishing agent composition and its result are demonstrated. In addition, the density | concentration (mass%) shown to each item in Table 1 is based on the mass of the abrasive | polishing agent composition which is a final product.

(1) Abrasive grains Polycrystalline diamond and single crystal diamond having the average particle diameter shown in Table 1 were used as abrasive grains. The source of polycrystalline diamond is, for each average particle size, an average particle size of 0.046 μm (manufactured by Sumiishi Materials Co., Ltd., SCM FINE DIA 0.025), an average particle size of 5 μm (manufactured by Sumiishi Materials Co., Ltd.) SCM FINE DIA 5), average particle diameter 6 μm (manufactured by Sumiishi Materials Co., Ltd., SCM FINE DIA 4-8), and average particle diameter 10 μm (manufactured by Sumiishi Materials Co., Ltd., SCM FINE DIA 6-12). The source of the single crystal diamond was an average particle size of 7 μm (manufactured by Tome Dia Co., Ltd., product number IRM 5-12). In addition, the average particle diameter of the diamond abrasive grains shown in Table 1 is a median diameter, and in the case of diamond abrasive grains having an average particle diameter of 5 μm or more (Examples 1 to 14 and Comparative Examples 2 to 5), a laser diffraction method is used. In the case of 0.046 μm diamond abrasive grains (Comparative Example 1), the measurement was performed by the dynamic light scattering method.

(2) Aqueous dispersion medium The aqueous dispersion medium was prepared in the composition shown in Table 1 with polyhydric alcohol, surfactant, and water (pure water). As the polyhydric alcohol, glycerin (manufactured by Miyoshi Oil Co., Ltd., food additive glycerin), ethylene glycol (manufactured by Mitsui Chemicals, Inc., monoethylene glycol), diglycerol (manufactured by Sakamoto Pharmaceutical Co., Ltd., diglycerin S) was used. . The surfactant is a carboxylic acid copolymer (ammonium salt) (Aron A-6114, manufactured by Toa Gosei Co., Ltd.) as a polycarboxylic acid surfactant, and polyethylene glycol-polypropylene glycol-polyethylene as a polyethylene glycol surfactant. Glycol (block copolymer) (manufactured by NOF Corporation, Pronon # 104) was used.

(3) Preparation of abrasive composition A necessary amount of polyhydric alcohol was weighed at room temperature. When two or more types of polyhydric alcohols were used, the polyhydric alcohols were mixed before mixing the ion exchange water. In addition, when mixing a polyhydric alcohol, surfactant, etc., it stirred for 10 minutes with the three one motor or the magnetic stirrer.

  Subsequently, the above-mentioned polyhydric alcohol or the like is mixed with a necessary amount of ion-exchanged water, stirred with a three-one motor or a magnetic stirrer for 10 minutes, and then the obtained mixed solution is filtered through a nylon mesh having an opening of 41 μm. As a result, an aqueous dispersion medium was obtained.

  Further, a required amount of diamond abrasive grains was weighed, put into the above-mentioned aqueous dispersion medium, and stirred for 45 minutes with a three-one motor while ultrasonically dispersing to obtain an abrasive composition.

(4) Viscosity Single cylindrical rotational viscometer defined in JIS standard Z8803 (last revised date: August 1, 1991) for the viscosity of the abrasive compositions of Examples 1 to 14 and Comparative Examples 1 to 5 The viscosity was measured by the viscosity measuring method. Specific measurement conditions were measured using a TVB-10 viscometer (manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25 ° C. of the abrasive composition. Table 1 shows the measurement results of the viscosities of the abrasive compositions of Examples 1 to 14 and Comparative Examples 1 to 5.

(5) pH
PH of the abrasive | polishing agent composition of Examples 1-14 and Comparative Examples 1-5 was measured by pH meter D51 (made by Horiba, Ltd.). Table 1 shows the measurement results of pH of the abrasive compositions of Examples 1 to 14 and Comparative Examples 1 to 5.

(6) Polishing Using the abrasive compositions of Examples 1 to 14 and Comparative Examples 1 to 5, the sapphire substrate was polished using a single-side polishing machine under the following polishing conditions.

(Polishing conditions)
Polishing machine: 12 inch single-side polishing machine EJ-300 manufactured by Engis
Surface plate: Copper (groove width: 2 mm, groove depth: 2 mm, land width: 3.6 mm)
Surface plate speed: 80 rpm
Polishing pressure: 46.7 kPa
Polishing time: 30 minutes Spray pressure of the abrasive composition: 55.2 kPa
Sapphire substrate: 2 inches in diameter

  In the evaluation of the characteristics of the surface to be polished, the polishing rate was determined by the following equation (1).

Polishing rate (μm / min) = (mass before polishing of sapphire substrate−mass after polishing of sapphire substrate) (g) ÷ (polished area of sapphire substrate) (cm ² ) ÷ (specific gravity of sapphire substrate) (g / cm ³ ) ÷ (Polishing time) (min) × 10000 (μm / cm) (Equation 1)

  Table 1 shows the results of the polishing rates of the abrasive compositions of Examples 1 to 14 and Comparative Examples 1 to 5.

  In the abrasive | polishing agent composition of Examples 1-14, the sapphire board | substrate was able to be grind | polished effectively with the grinding | polishing rate of 0.695 (micrometer / min) or more.

  The polishing composition containing glycerin as the polyhydric alcohol generally had a high polishing rate (see comparison between Examples 2-8 and Examples 9-12).

  Moreover, as shown in Examples 3 and 6 to 9, when glycerin and / or ethylene glycol is contained in a total of 60% by mass as a polyhydric alcohol, Example 3 containing 60% by mass of glycerin alone has the highest polishing rate. It was. In Examples 6 to 8 containing 60% by mass of two kinds of polyhydric alcohols of glycerin and ethylene glycol, the polishing rate tended to increase in the order of Examples 8, 7, and 6 in which the ratio of glycerin increased. .

  From the comparison between Examples 3 and 14, the abrasive composition of diamond using a polycrystalline diamond had a higher polishing rate than the one using single crystal diamond.

  Further, from the comparison between Examples 1, 3, and 13, the polishing rate increased as the average particle diameter of the polycrystalline diamond abrasive grains contained in the abrasive composition increased to 5 μm, 6 μm, and 10 μm.

  The present invention can be used as an abrasive composition useful for efficiently polishing a hard substrate having a semiconductor crystal film.

Claims (6)

Abrasive grains of single crystal diamond and / or polycrystalline diamond having an average particle size of 0.1 to 15 μm;
An aqueous dispersion medium containing a polyhydric alcohol and water,
An abrasive composition having a viscosity of 2.0 to 100 mPa · s.   The abrasive | polishing agent composition of Claim 1 which contains 30-90 mass% of the said polyhydric alcohol in the whole quantity. The abrasive composition according to claim 1 or 2, wherein the polyhydric alcohol is at least one selected from the group consisting of compounds having a structure represented by the following chemical formula (I) or (II).
HO— (CHR ¹ ) _n —R ² (I)
(In the chemical formula (I), n is a natural number of ¹ to 6. R ¹ represents H or OH, and n R ^{1 s} may be the same or different. R ² represents H or OH. Provided that at least one of n R ¹ and R ² is OH.)
HO — ((CHR ³ ) _m —O) _n —H (II)
(In the chemical formula (II), m is 2 or 3, and n is 2 or 3. R ³ represents H, OH, or CH ₃ , and m R ³ may be the same or different. Good.)   The abrasive | polishing agent composition of Claim 3 which contains at least 1 type chosen from the group which consists of glycerol, diglycerol, and ethylene glycol as said polyhydric alcohol.   The abrasive composition according to any one of claims 1 to 4, wherein the pH is 3 to 12.   The abrasive | polishing agent composition as described in any one of Claims 1-5 used when grind | polishing the hard board | substrate which consists of at least any one of a sapphire, a zinc oxide, a spinel, a group III nitride, and silicon carbide.