TW201739893A - Polishing composition - Google Patents

Abstract

Provided is a polishing composition for polishing a material to be polished. This polishing composition contains diamond abrasive and non-diamond abrasive, and in terms of weight, the ratio (B/A) of the content of non-diamond abrasive (B) to diamond abrasive (A) is greater than 2.

Description

Grinding composition

The present invention relates to a composition for polishing. Specifically, the polishing composition used for polishing the polishing target material.

In addition, the present application is based on the Japanese Patent Application No. 2016-071477 filed on March 31, 2016, the priority of which is incorporated herein by reference. In.

The surface of materials such as diamond, sapphire (alumina), tantalum carbide, boron carbide, tungsten carbide, tantalum nitride, titanium nitride, etc., is usually processed by lapping the diamond abrasive grains to the grinding platen. . However, in the polishing using the diamond abrasive grains, scratches occur on the surface of the object to be polished. Further, the diamond abrasive grains remain on the surface of the object to be polished. Therefore, defects or deformation are likely to occur on the surface of the object to be polished. Then, after polishing using the diamond abrasive grains, the polishing pad is used to supply a polishing slurry between the polishing pad and the object to be polished, and polishing (polishing) is performed. Or instead of the grinding, review polishing. Patent Documents 1 and 3 are cited as documents for revealing such conventional techniques.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Application Publication No. 2011-121153

Patent Document 2: Japanese Patent Application Publication No. 2012-248569

Patent Document 3: Japanese Invention Patent Application Publication No. 2014-24154

In the above-mentioned conventional technical literature, it is proposed to improve the polishing rate or the surface flatness after polishing by working on the components of the abrasive (the polishing composition) used for polishing, such as abrasive grains or oxidizing agents. Here, the so-called polishing rate means the amount of the surface on which the object to be polished is removed per unit time. However, even with such a technique, there is still insufficient room for improvement in terms of practical requirements related to polishing rate and surface flatness.

The present invention has been made in view of the above circumstances. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a polishing composition which can achieve both a polishing rate and a surface flatness at a high level. Another object of the association is to provide a method of producing an abrasive using the above-described polishing composition.

According to the present invention, there is provided a polishing composition used for polishing a material to be polished. The abrasive composition comprises diamond abrasive particles and non-diamond abrasive particles. Further, the ratio (B/A) of the content B of the non-diamond abrasive grains to the content A of the diamond abrasive grains is 2 < (B/A) on a weight basis.

By combining the diamond abrasive grains and the non-diamond abrasive grains in such a manner as to have the specific content ratio described above, it is possible to achieve both the polishing rate and the surface flatness at a high level.

Further, according to the present invention, there is provided a method of producing an abrasive. This manufacturing method includes supplying any of the polishing compositions disclosed herein to an object to be polished, and polishing the object to be polished. By such a manufacturing method, it is possible to efficiently provide an abrasive having a polished surface having a good surface flatness.

Form of implementing the invention

Hereinafter, a suitable embodiment of the present invention will be described. Further, in the present specification, what is necessary for the implementation of the present invention other than the matters specifically mentioned by the present invention is based on the prior art in the field, and can be grasped as a design matter. The present invention can be implemented in accordance with the teachings of the present disclosure and the technical common knowledge in the field.

<grinding object>

The polishing composition disclosed herein can be applied to polishing of an object to be polished made of various materials. The material of the object to be polished may be, for example, a metal or a semimetal such as tantalum, aluminum, nickel, tungsten, copper, tantalum, titanium, stainless steel or tantalum, or an alloy thereof; quartz glass, aluminosilicate glass, glassy carbon Glassy materials such as alumina, vermiculite, sapphire, tantalum nitride, tantalum nitride, titanium carbide, etc.; compounds such as tantalum carbide, gallium nitride, gallium arsenide, indium arsenide, indium phosphide, etc. A semiconductor substrate material; a resin material such as a polyimide resin or the like. Among these, it may be an object to be polished which is composed of a plurality of materials. Among them, it is preferably used for the grinding of a high hardness material having a Vickers hardness of 1500 Hv or more. The Vickers hardness of the material to be polished is preferably 1800 Hv or more. The Vickers hardness of the material to be polished is, for example, 2000 Hv or more, and is typically 2200 Hv or more. The upper limit of the Vickers hardness is not particularly limited, but may be about 7000 Hv or less. The upper limit of the Vickers hardness is, for example, 5000 Hv or less, and typically 3000 Hv or less. Further, in the present specification, the Vickers hardness is measured in accordance with JIS R 1610:2003. The international standard corresponding to the above JIS standard is ISO 14705:2000.

Examples of the material having a Vickers hardness of 1500 Hv or more include diamond, sapphire (alumina), tantalum carbide, boron carbide, zirconium carbide, tungsten carbide, tantalum nitride, titanium nitride, and gallium nitride. The polishing composition disclosed herein is preferably applicable to a single crystal surface of the above materials which are mechanically and chemically stable. Among them, the surface of the object to be polished is preferably composed of tantalum carbide. Tantalum carbide is expected to be a semiconductor substrate material which is excellent in power loss and heat resistance. Improve the surface property shape of the tantalum carbide substrate The practical advantages are particularly large. The polishing composition disclosed herein is particularly preferably applied to the single crystal surface of tantalum carbide.

<grinding composition> (abrasive grain)

The abrasive compositions disclosed herein comprise diamond abrasive particles and non-diamond abrasive particles. Further, the ratio (B/A) of the content B of the non-diamond abrasive grains to the content A of the diamond abrasive grains is 2 < (B/A) on a weight basis. Thus, by combining diamond abrasive grains and non-diamond abrasive grains in a specific content ratio, even for a high hardness material surface, both the polishing rate and the surface flatness can be achieved at a high level. As a reason for obtaining such an effect, for example, it is considered as follows. In other words, in the polishing using the polishing composition containing a small amount of diamond abrasive grains with respect to the non-diamond abrasive grains, since the diamond particles having high hardness are present between the non-diamond particles, the surface of the polishing object due to the diamond particles is suppressed. In the case of cracking, the unevenness of the surface of the object to be polished is efficiently reduced (flattened). Judging this helps the polishing rate and surface flatness increase. However, it is not construed as limited by this reason.

The content ratio (B/A) of the diamond abrasive grains to the non-diamond abrasive grains in the polishing composition may be more than 2. That is, 2 < (B / A). From the viewpoint of achieving both the polishing rate and the surface flatness, the content ratio (B/A) is, for example, 10 or more, and is usually 50 or more, and for example, 100 or more. The polishing composition used in combination of the diamond abrasive grains and the non-diamond abrasive grains in such a content ratio (B/A) is such that an appropriate amount of the diamond particles exists between the non-diamond particles. In this way, it can be properly played The applicable effects of the techniques disclosed herein. The upper limit of the content ratio (B/A) is not particularly limited, and may be, for example, 10,000 or less, preferably 8,000 or less, more preferably 5,000 or less, still more preferably 2,000 or less, and particularly preferably 1,500 or less. The content ratio (B/A) may be, for example, 1000 or less, and is typically 500 or less, and may be, for example, 300 or less. When the above content ratio (B/A) is made small, the polishing rate improving effect of the surface of the polishing target material can be achieved at a higher level. The technique disclosed herein is preferably carried out, for example, in such a manner that the ratio (B/A) of the content of the diamond abrasive grains and the non-diamond abrasive grains in the polishing composition is 100 or more and 10,000 or less. The above B/A can be preferably carried out, for example, at 120 or more and 1,500 or less, and typically 150 or more and 300 or less.

The diamond particles contained in the above-mentioned diamond abrasive grains may be various diamond particles containing diamond as a main component. Here, the diamond particles containing diamond as a main component means that 90% by weight or more (generally 95% by weight or more, typically 98% by weight or more) of the particles are particles of diamond. Examples of the diamond particles that can be used include single crystal diamonds, polycrystalline diamonds, natural diamonds, synthetic diamonds, and the like. However, diamond particles that can be used are not limited by these. Examples of the synthetic diamonds referred to herein include diamonds obtained by graphite in a high-temperature and high-pressure metal solvent by static ultrahigh pressure method (static pressure method), and dynamic ultrahigh pressure method using high temperature and high pressure by explosion. A diamond obtained by (impact method) or a diamond obtained by super-high-pressure sintering of fine particles of a single crystal diamond by a metal binder. The diamond abrasive grains of the technique disclosed herein may include one or a combination of two or more of such diamond particles.

The shape of the diamond abrasive particles, that is, the shape, may be spherical or non-spherical. Specific examples of the non-spherical diamond abrasive grains include a plate shape, a needle shape, and a spindle shape. In the technique disclosed herein, the diamond abrasive grains contained in the polishing composition may be in the form of primary particles or in the form of secondary particles in which a plurality of primary particles are combined. Further, the diamond abrasive grains in the form of primary particles and the diamond abrasive grains in the form of secondary particles may be mixed.

As the diamond abrasive grains, those having an average primary particle diameter (hereinafter also referred to simply as "D1 _A ") of 10 nm or less are preferably used. The D1 _{A of the} diamond abrasive grains is preferably 8 nm or less, more preferably 6 nm or less, from the viewpoint of increasing the surface flatness after polishing or the number of particles per weight. The lower limit of D1 _A is not particularly limited, and is, for example, 0.1 nm or more, and is usually 0.3 nm or more, and typically 0.5 nm or more. From the viewpoint of the polishing rate and the like, D1 _{A is} preferably 1 nm or more, more preferably 2 nm or more. For example, diamond abrasive grains having a D1 _A of 0.1 nm or more and 10 nm or less are preferable, and diamond abrasive grains of 1 nm or more and 8 nm or less are more preferable, and particularly preferably 2 nm or more and 6 nm or less.

The content A of the diamond abrasive grains in the polishing composition is typically 0.001% by weight or more, and is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, and particularly preferably 0.1% from the viewpoint of shortening the processing time. More than weight%. However, the content A is not particularly limited as long as the above relationship is satisfied between the content B and the content B of the non-diamond abrasive grains. Here, when the diamond abrasive grains contain a plurality of types of diamond particles, the content A is the total content of the plurality of diamond particles of the same type. From the stability of grinding and cost reduction, etc. In view of the above, the content A of the diamond abrasive grains is usually 3% by weight or less, preferably 1% by weight or less, more preferably 0.5% by weight or less, and still more preferably 0.2% by weight or less. The technique disclosed herein is preferably carried out, for example, in such a manner that the content A of the diamond abrasive grains of the polishing composition is 0.005% by weight or more and 0.5% by weight or less. The above content A is preferably from 0.015% by weight to 0.2% by weight.

The non-diamond particles contained in the non-diamond abrasive grains are not particularly limited as long as they are particles made of a material other than diamond. For example, the non-diamond particles may be any of inorganic particles, organic particles, and organic-inorganic composite particles. For example, oxide particles such as vermiculite particles, alumina particles, cerium oxide particles, chromium oxide particles, titanium oxide particles, zirconia particles, magnesium oxide particles, manganese oxide particles, zinc oxide particles, or iron oxide particles may be mentioned; Nitride particles such as tantalum nitride particles and boron nitride particles; carbide particles such as niobium carbide particles and boron carbide particles; and abrasive grains substantially composed of any of carbonate or calcium carbonate. The non-diamond particles may be used singly or in combination of two or more. Among them, oxide particles such as vermiculite particles, alumina particles, cerium oxide particles, chromium oxide particles, zirconia particles, manganese oxide particles, and iron oxide particles are preferably formed into a good surface with high efficiency. Among them, vermiculite particles, alumina particles, zirconia particles, chromium oxide particles, and iron oxide particles are more preferable, and vermiculite particles, alumina particles, and zirconia particles are particularly preferable.

Suitable examples of the non-diamond particles usable in the technique disclosed herein include vermiculite particles. As the vermiculite particles, colloidal vermiculite, dry vermiculite or the like is preferably used. In the example of the dry method vermiculite as referred to herein, a vermiculite (smoked stone) obtained by burning a decane compound such as hafnium tetrachloride or trichloromethane, which is typically produced in a hydrogen flame, or by a metal A meteorite formed by the reaction of hydrazine with oxygen. Further, in the case of the colloidal vermiculite, a solution containing an alkali metal containing Na, K or the like and a phthalic acid-containing liquid of SiO ₂ (for example, a liquid containing sodium citrate) is used for the raw material, or A vermiculite (alkoxide-based vermiculite) produced by a hydrolysis condensation reaction of an alkoxydecane such as tetraethoxynonane or tetramethoxynonane.

When the vermiculite particles are used as the non-diamond particles, the proportion of the vermiculite particles contained in the entire non-diamond abrasive grains contained in the polishing composition is preferably 70% by weight or more. The technique disclosed herein is preferably carried out in such a manner that the total proportion of the vermiculite particles in the total weight of the non-diamond abrasive grains contained in the polishing composition is greater than 85% by weight. The proportion of the above-mentioned vermiculite particles is more preferably 95% by weight or more, particularly preferably 98% by weight or more, and particularly preferably 99% by weight or more. In particular, it is preferred that the polishing composition of the non-diamond abrasive grains contained in the polishing composition is a polishing composition of vermiculite particles.

The shape of the non-diamond abrasive grains, that is, the shape, may be spherical or non-spherical. Specific examples of the non-diamond non-diamond abrasive grains include a peanut shape (that is, a shape of a shell of a groundnut), a cocoon shape, a jelly color shape, and a football shape. In the technique disclosed herein, the non-diamond abrasive grains contained in the polishing composition may be in the form of primary particles or in the form of secondary particles in which a plurality of primary particles are combined. Also, in the form of primary particles, diamond abrasive grains and diamonds in the form of secondary particles Abrasive grains may also be present in admixture. In a preferred aspect, at least a portion of the non-diamond abrasive particles are included in the polishing composition in the form of secondary particles.

As the non-diamond abrasive grains, it is preferable to use an average primary particle diameter (hereinafter also referred to as "D1 _B " only) which is larger than 10 nm. From the viewpoint of the polishing rate and the like, D1 _{B is} preferably 15 nm or more, more preferably 20 nm or more, still more preferably 25 nm or more, and particularly preferably 30 nm or more. The upper limit of D1 _B is not particularly limited, but is preferably about 3,000 nm or less, preferably 2,000 nm or less, and more preferably 800 nm or less. For example, D1 _B may be 500 nm or less (for example, 300 nm or less), typically 200 nm or less (for example, 130 nm or less), and may be, for example, 110 nm or less (typically 80 nm or less). For example, from the viewpoint of achieving a higher polishing rate and surface flatness, D1 _B is preferably a non-diamond abrasive grain of 12 nm or more and 80 nm or less, more preferably a non-diamond abrasive grain of 15 nm or more and 60 nm or less. It is preferably 20 nm or more and 50 nm or less. For example, D1 _B may be a non-diamond abrasive grain of 25 nm or more and 40 nm or less (for example, 35 nm or less).

In a preferred aspect, the D1 _B system of the non-diamond abrasive particles is larger than the D1 _{A of the} diamond abrasive particles. That is, D1 _A <D1 _B is satisfied. Thereby, the unevenness of the surface of the object to be polished can be more effectively eliminated. For example, the relationship between D1 _A and D1 _B is preferably such that 1 < (D1 _B / D1 _A ) < 500, more preferably 2 < (D1 _B / D1 _A ) < 200, and particularly preferably 2.5 ≦ (D1 _B) /D1 _A ) ≦ 50, especially good for 2.5 ≦ (D1 _B / D1 _A ) ≦ 20. By combining the diamond abrasive grains and the non-diamond abrasive grains in a specific average primary particle diameter ratio, the polishing rate and the surface flatness can be achieved at a higher level. The technique disclosed herein may, for example, satisfy the relationship between D1 _A and D1 _B by 3≦(D1 _B /D1 _A )≦12, preferably 5≦(D1 _B /D1 _A )≦10, and especially 5≦(D1 _B /D1) _A ) The aspect of ≦8 is preferably implemented.

From the viewpoint of more effectively exerting the effect by the combination of the diamond abrasive grains and the non-diamond abrasive grains, D1 _{B is} preferably 10 nm or more larger than D1 _A. Further, the value obtained by subtracting D1 _A from D1 _B (i.e., D1 _{B -} D1 _A ) is preferably 60 nm or less, more preferably 50 nm or less, and particularly preferably 40 nm or less. For example, D1 _{B -} D1 _A may also be 30 nm or less.

Furthermore, in the technique disclosed herein, the average primary particle diameter of the diamond abrasive grains and the non-diamond abrasive grains refers to the specific surface area (BET value) measured by the BET method, by the average primary particle diameter [nm ] = 6000 / (true density [g / cm ³ ] × BET value [m ² / g]) calculated particle size. For example, when the non-diamond abrasive grains are composed of vermiculite particles, the average primary particle diameter can be calculated by an average primary particle diameter [nm] = 2727 / BET value [m ² /g]. The measurement of the specific surface area can be carried out, for example, by using the surface name measuring device manufactured by MICROMERITICS Co., Ltd. under the trade name "Flow Sorb II 2300".

The content B of the non-diamond abrasive grains in the polishing composition is about 1% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more, and particularly preferably 20% by weight, from the viewpoint of polishing rate and the like. %the above. However, the content B is not particularly limited as long as the above relationship is satisfied between the content A and the diamond abrasive grains. Here, when the non-diamond abrasive grains contain a plurality of types of particles, the content B is the total content of the plurality of types of particles. From the viewpoint of surface flatness after polishing or stability of polishing, the content B of the non-diamond abrasive grains is preferably about 50% by weight or less. It is preferably 45 wt% or less, more preferably 40 wt% or less, still more preferably 30 wt% or less. The technique disclosed herein can be preferably carried out, for example, in such a manner that the content B of the non-diamond abrasive grains in the polishing composition is 10% by weight or more and 40% by weight or less (preferably 20% by weight or more and 30% by weight or less).

In a preferred aspect, the diamond abrasive particles and the non-diamond abrasive particles are each selected to be suitable for the non-diamond abrasive particles of the diamond abrasive particles at the pH of the polishing composition and the pH of the polishing composition. The 仄 other potential shows the reverse polarity (the opposite charge) and is used. Further, it is preferable to use a metastatic potential of the diamond abrasive grains at the pH of the polishing composition and a metamorphic potential of the polishing target material at the pH of the polishing composition. The technique disclosed herein is a state in which the other potentials of the diamond abrasive grains of the polishing composition at the pH of the polishing composition and the non-diamond abrasive grains and the polishing target material at the pH of the polishing composition are reverse polarity. It is preferably implemented. For example, when the non-diamond abrasive grains and the other potential of the material to be polished exhibit a negative polarity (negative), it is preferable to use a diamond abrasive grain exhibiting a positive (positive) positive potential. If this is the case, the diamond particles can be pulled to the surface of the non-diamond particles or the object to be polished by electrostatic attraction in the polishing composition. Further, it is possible to suitably achieve a state in which the diamond particles are present between the non-diamond particles and the surface of the object to be polished. Therefore, the performance improvement effect by using a small amount of diamond abrasive grains with respect to non-diamond abrasive grains can be more suitably exhibited.

Further, the zeta potential of the diamond abrasive grains, the non-diamond abrasive grains, and the material to be polished at the pH of the polishing composition is, for example, electrophoresis Measured by dynamic light scattering or electroacoustic spectroscopy. For the measurement of the electrophoretic dynamic light scattering method, for example, "ELS-Z" manufactured by Otsuka Electronics Co., Ltd. can be used. For the measurement of the electroacoustic spectroscopy, for example, "DT-1200" manufactured by Dispersion Technology Inc. can be used. Further, the measurement of the other potential of the material to be polished can be replaced by the measurement of the other potential of the fine particles formed of the same material as the material to be polished. Alternatively, for example, a scanning electron microscope can also be used. The material to be polished may be immersed in a liquid containing fine particles having a known gas potential, and the surface of the material to be polished after washing may be observed. Here, the washing is performed, for example, in running water for about 10 seconds. At this time, the amount of the fine particles adhering to the surface of the polishing target material after washing can be known as the sign of the value of the potential of the polishing target material in the same liquid. That is, it can be known that the polarity of the potential is positive or negative. When the object to be measured is diamond abrasive grains or non-diamond abrasive grains, each of the abrasive grains is dispersed in pure water as a specific procedure to prepare an aqueous solution for measurement having an abrasive concentration of 1 to 30% by weight. Then, the pH is adjusted to the same pH as the polishing composition by, for example, a pH adjuster such as potassium hydroxide or nitric acid. Thereafter, the metastatic potential of each abrasive grain can be obtained by using the above-described solar potential measuring apparatus. In addition, when the object to be measured is a material to be polished, the particles (powder material) formed of the material to be polished are dispersed in pure water to prepare an aqueous solution for measurement having a particle concentration of 1 to 30% by weight. Then, the pH is adjusted to the same pH as the polishing composition by, for example, a pH adjuster such as potassium hydroxide or nitric acid. Thereafter, the statist potential of the material to be polished can be obtained by using the above-described sputum potential measuring device. The amphoteric potential of the diamond abrasive particles and the non-diamond abrasive particles can be adjusted, for example, by changing the material of the abrasive particles or modifying the surface of the abrasive particles. Modified example of abrasive surface For example, an organofunctional group modification can be mentioned.

(grinding aid)

The polishing composition disclosed herein preferably contains a grinding aid. The grinding aid is a component that enhances the effect of polishing. Water-soluble grinding aids are typically used. It is considered that the polishing aid exhibits an effect of deteriorating the surface of the object to be polished during polishing, and contributes to the grinding of the abrasive grains by causing the surface of the object to be polished to be weak. Here, as a deterioration, oxidative deterioration is exemplified. However, it is not to be construed as being limited by these functions or institutions.

Examples of the polishing aid include a peroxide such as hydrogen peroxide; a nitrate compound such as nitric acid, a salt of ferric nitrate, silver nitrate, aluminum nitrate or a complex of ammonium cerium nitrate; potassium peroxysulfate and peroxygen peroxide; a persulfuric acid compound such as persulfuric acid such as disulfuric acid, ammonium persulfate or potassium persulfate thereof; a chlorine compound such as chloric acid or a salt thereof; perchloric acid or a salt thereof; potassium bromate having a salt thereof; a bromine compound; an iodine compound such as iodic acid, ammonium iodate, a periodic acid, a sodium periodate or a potassium periodate; or a ferric acid such as ferric acid or a salt thereof; Permanganic acid such as permanganic acid, sodium permanganate or potassium permanganate; chromic acid such as chromic acid, potassium chromate or potassium dichromate; vanadic acid, ammonium vanadate , vanadic acid such as sodium vanadate or potassium vanadate; tannic acid such as perrhenic acid or its salt; molybdic acid such as molybdic acid, its molybdenum ammonium, disodium molybdate, etc.; perrhenic acid or its salt Terpenic acid; tungstic acid such as tungstic acid or a salt thereof, such as disodium tungstate. These may be used alone or in combination of two or more.

In a preferred aspect, the polishing composition comprises a composite Metal oxides act as grinding aids. Examples of the composite metal oxide include a nitrate metal salt, a ferrite, a permanganic acid, a chromic acid, a vanadic acid, a decanoic acid, a molybdic acid, a decanoic acid, and a tungstic acid. Among them, vanadic acid, molybdic acid, and tungstic acid are preferred, and vanadic acid is more preferred.

In a more preferable aspect, as the above composite metal oxide, a composite metal oxide CMO having a monovalent or divalent metal element or a transition metal element of a Group 5 or Group 6 of the periodic table is used. However, the monovalent or divalent metal element herein does not include a transition metal element. Suitable examples of the above-mentioned monovalent or divalent metal element or ammonia include Na, K, Mg, Ca, and ammonia. Among them, more preferred are Na and K. The transition metal element of the Group 5 or Group 6 of the periodic table is preferably selected from the 4th cycle, the 5th cycle, and the 6th cycle, and more preferably selected from the 4th cycle and the 5th cycle, and more preferably Choose between 4 cycles. The above transition metal element is preferably selected from Group 5. Specific examples thereof include V, Nb, Ta, Cr, Mo, and W. Among them, more preferably V, Mo, W, and particularly preferably V.

When the polishing composition disclosed herein contains a composite metal oxide as a polishing aid, it is preferable that the polishing aid other than the composite metal oxide further contains an oxygen-containing material capable of supplying oxygen to the composite metal oxide. Thereby, the chemical action of the composite metal oxide is continuously exerted. Moreover, the polishing rate of the polishing is meaningfully increased, and the smoothness and flatness of the material to be polished can be highly balanced. Here, the composite metal oxide is preferably a composite metal oxide CMO. Suitable examples of the oxygen-containing material include hydrogen peroxide, ozone, and peracid. Among them, hydrogen peroxide is particularly preferred.

The concentration of the grinding aid in the polishing composition, that is, The amount is usually 0.1% by weight or more as appropriate. The concentration is preferably 0.5% by weight or more, and more preferably 1% by weight or more (for example, 1.5% by weight or more) from the viewpoint of efficiently and efficiently balancing the polishing rate and the flatness. Moreover, the concentration of the above-mentioned polishing aid is usually 15% by weight or less, preferably 10% by weight or less, and more preferably 8% by weight or less, from the viewpoint of improvement in smoothness. The concentration of the above polishing aid is, for example, preferably 5% by weight or less or 3% by weight or less.

When the oxygen atom is supplied to the composite metal oxide and the metal oxide as the polishing aid, the concentration of the composite metal oxide is usually 0.1% by weight or more. Here, the composite metal oxide is preferably a composite metal oxide GMO. The concentration is preferably 0.5% by weight or more, and more preferably 1.5% by weight or more from the viewpoint of efficiently and efficiently balancing the polishing rate and the flatness. Further, the concentration of the above composite metal oxide is usually 10% by weight or less, more preferably 3% by weight or less, and particularly preferably 2.5% by weight or less. The concentration of the oxygen-containing substance is usually 0.1 to 10% by weight, and the concentration is preferably 0.5 to 3% by weight, more preferably 1 to 2% by weight, from the viewpoint of preferably exhibiting an oxygen supply.

(other ingredients)

The polishing composition disclosed herein may further contain a chelating agent, a tackifier, a dispersing agent, a surface protecting agent, a wetting agent, a pH adjusting agent, a surfactant, and the like, within a range not impairing the effects of the present invention. Well-known additives which can be used in the polishing composition of organic acids, organic acid salts, inorganic acids, inorganic acid salts, rust inhibitors, preservatives, antifungal agents and the like. The polishing composition referred to herein is a composition for polishing a high hardness material, for example, a composition for polishing a tantalum carbide substrate. The content of the above additives may be appropriately set according to the purpose of the addition, and the detailed description is omitted since it is not a feature of the present invention.

(solvent)

The solvent used in the polishing composition is not particularly limited as long as it can disperse the abrasive grains. As the solvent, ion-exchanged water (deionized water), pure water, ultrapure water, distilled water or the like can be preferably used. The polishing composition disclosed herein may further contain an organic solvent which can be uniformly mixed with water as needed. Examples of the organic solvent that can be uniformly mixed with water include a lower alcohol and a lower ketone. Usually, 90% by volume or more of the solvent contained in the polishing composition is preferably water, and 95% by volume or more (typically 99 to 100% by volume) is more preferably water.

The pH of the polishing composition is usually about 2 to 12, which is suitable. When the pH of the polishing composition is within the above range, it is easy to achieve a practical polishing rate. The pH of the polishing composition is preferably from 3 to 11, more preferably from 4 to 10, from the viewpoint of more exerting the effects of the techniques disclosed herein.

<Modulation of polishing composition>

The method for producing the polishing composition disclosed herein is not particularly limited. Each component contained in the polishing composition can be mixed using a well-known mixing device. As a well-known mixing device, for example, wing stirring can be mentioned. Machine, ultrasonic disperser, homogenizer, etc. The aspect in which these components are mixed is not particularly limited. For example, all the components may be mixed at once, or may be mixed in an appropriately set order.

The polishing composition disclosed herein may be in one dosage form or in a multiple dosage form including two dosage forms. For example, the liquid A containing the component of a part of the components of the polishing composition and the liquid B containing the remaining component may be mixed and used for polishing the object to be polished. Here, the liquid A is typically a component other than a solvent.

<concentrate>

The polishing composition disclosed herein may be in a concentrated form (that is, in the form of a concentrated liquid of the polishing liquid) before being supplied to the object to be polished. The polishing composition of such a concentrated form is advantageous from the viewpoints of convenience in production, distribution, storage, and the like, and cost reduction. The concentration ratio can be, for example, about 2 to 5 times in terms of volume.

The polishing composition in the form of the concentrated liquid can be diluted at a desired timing to prepare a polishing liquid, and the polishing liquid can be used in the form of being supplied to the object to be polished. The above dilution can be usually carried out by adding the above-mentioned solvent to the concentrate and mixing. In addition, when the solvent is a mixed solvent, only a part of the components of the solvent may be added and diluted, or a mixed solvent containing a constituent component different from the solvent may be added and diluted. Further, as described later, in the polishing composition for a plurality of dosage forms, a part of the agents may be diluted, and then the other agent may be mixed to prepare a polishing liquid, or the mixture may be diluted and mixed. The composition is prepared to prepare a slurry.

The content of the abrasive grains in the above concentrate may be, for example, 70% by weight or less. The content may be 60% by weight or less, or may be 50% by weight or less (for example, 40% by weight or less) from the viewpoint of stability of the polishing composition, filterability, and the like. Here, the stability of the polishing composition is, for example, the dispersion stability of the abrasive grains. Moreover, the content of the abrasive grains can be, for example, 2% by weight or more, preferably 10% by weight or more, and more preferably 20% by weight or more from the viewpoints of convenience in production, distribution, storage, and the like. For example, 30% by weight or more).

<grinding method>

The polishing composition disclosed herein is used for polishing of an object to be polished, for example, by including the following operation.

That is, a polishing liquid (slurry) containing any of the polishing compositions disclosed herein is prepared. In order to prepare the polishing liquid, an operation of applying concentration adjustment, pH adjustment, or the like to the polishing composition may be included to prepare a polishing liquid. Here, as the concentration adjustment, for example, dilution can be mentioned. Alternatively, the above polishing composition may be used as a polishing liquid as it is. Further, in the case of preparing a polishing composition for a plurality of dosage forms, in order to prepare the polishing liquid, one or a plurality of agents may be mixed before the mixing, and the mixture may be diluted after the mixing.

Next, the polishing liquid is supplied to the surface of the object to be polished, and is ground by a usual method. For example, an object to be polished is placed on a general polishing apparatus, and the polishing liquid is supplied to the grinding liquid by the polishing pad of the polishing apparatus. Grinding the surface of the object (grinding the object surface). Typically, while the slurry is continuously supplied, the polishing pad is pressed against the surface of the object to be polished, and the two are relatively moved (for example, rotationally moved). Through the polishing step, the grinding of the object to be polished is completed.

According to this specification, a polishing method for polishing a material to be polished and a method for producing an abrasive using the polishing method are provided. The polishing method is characterized by comprising the step of polishing the object to be polished using the polishing composition disclosed herein. A preferred aspect of the grinding process comprises a preliminary polishing step and a finishing polishing step. The preliminary polishing step described here is a step of performing preliminary polishing on the object to be polished. In a typical aspect, the preliminary polishing step is performed in a polishing step immediately prior to the completion of the polishing step. The preliminary polishing step may be a polishing step of one stage or a polishing step of a plurality of stages of two or more stages. Further, the finishing polishing step as described herein is a step of performing finish polishing on the object to be polished which has been subjected to preliminary polishing, and refers to a polishing step which is finally disposed in the polishing step using the polishing slurry containing the abrasive grains. That is, the finishing polishing step refers to a grinding step disposed on the most downstream side. In the polishing method comprising the preliminary polishing step and the finishing polishing step, the polishing composition disclosed herein can be used in the preliminary polishing step, in the finishing polishing step, or in the preliminary polishing step and completion. Used in both polishing steps.

In a preferred aspect, the polishing step using the polishing composition described above completes the polishing step. The polishing composition disclosed herein is effective in reducing the surface roughness on the surface after grinding, It is particularly preferable to use a polishing composition used in the finishing polishing step of the surface of the material to be polished. That is, it is particularly useful as a composition for finishing polishing.

In other preferred aspects, the polishing step using the polishing composition described above may be a preliminary polishing step. The polishing composition disclosed herein is suitable as a polishing composition used in the preliminary polishing step of the surface of the polishing target material in view of achieving a high polishing rate. That is, it is suitable as a composition for preliminary polishing. When the preliminary polishing step includes a polishing step of a plurality of stages of two or more stages, the polishing step of two or more of them may be carried out using any of the polishing compositions disclosed herein. The polishing composition disclosed herein can be preferably applied to the preliminary polishing of the front stage. That is, the polishing composition can be preferably applied to the preliminary polishing on the upstream side. For example, it can also be preferably used in the first preliminary polishing step which is subjected to a polishing step to be described later. It is also preferably used in one grinding step.

The preliminary polishing and the finishing polishing can also be applied to any of the polishing of the single-side polishing device and the polishing of the double-sided polishing device. In the single-side polishing apparatus, an object to be polished is attached to a ceramic plate with a wax, or a holder called a carrier is used to hold the object to be polished. Then, while the polishing composition is supplied, the polishing pad is pressed against one surface of the object to be polished, and both are relatively moved (for example, rotationally moved), and one surface of the object to be polished is polished. In the double-side polishing apparatus, a holder called a carrier is used to hold the object to be polished. Then, while supplying the polishing composition from above the object to be polished, the polishing pad is pressed against the opposing surface of the object to be polished. By rotating the opposing polishing pads in opposite directions while simultaneously grinding Grind the two sides of the object.

The polishing pad used in each polishing step disclosed herein is not particularly limited. For example, any of a non-woven fabric type, a suede type, a rigid foamed polyurethane type, an abrasive-containing one, and an abrasive-free one can be used.

The abrasives ground by the methods disclosed herein are typically washed after polishing. This cleaning can be carried out using a suitable cleaning solution. The washing liquid to be used is not particularly limited, and can be suitably used by a well-known person.

Also, the polishing method disclosed herein may include any other steps in addition to the above-described preliminary polishing step and finishing polishing step. As such a step, a polishing step performed before the preliminary polishing step can be mentioned. The polishing step is a step of polishing the object to be polished by, for example, pressing the surface of the polishing platen such as a cast iron platen to the object to be polished. Therefore, no polishing pad is used in the grinding step. The polishing step is typically performed by supplying abrasive grains between the polishing platen and the object to be polished. Here, diamond abrasive grains are typically used. Again, the grinding method disclosed herein may include additional steps prior to the preliminary polishing step or between the preliminary polishing step and the finished polishing step. As a procedure added here, a washing step or a polishing step can be mentioned.

<Method for Producing Abrasives>

In the technique disclosed herein, a method of manufacturing an abrasive comprising a polishing step using the above-described polishing composition and by the method The manufactured abrasive. That is, in accordance with the technique disclosed herein, there is provided a method of producing an abrasive, and an abrasive produced by the method, comprising: supplying any of the polishing disclosed herein to an object to be polished composed of a material to be polished The object to be polished is ground with a composition. The above manufacturing method can be carried out by suitably employing the contents of any of the polishing methods disclosed herein. According to the above manufacturing method, the abrasive having the polished surface having good surface flatness can be efficiently provided. Here, examples of the polishing material include a tantalum carbide substrate.

As described above, according to the present embodiment, the polishing composition used for polishing the polishing target material is provided. The abrasive composition comprises diamond abrasive particles and non-diamond abrasive particles. Further, the ratio (B/A) of the content B of the non-diamond abrasive grains to the content A of the diamond abrasive grains is 2 < (B/A) on a weight basis.

By combining the diamond abrasive grains and the non-diamond abrasive grains in such a specific content ratio, the polishing rate and the surface flatness can be achieved at a high level.

In a preferred aspect of the polishing composition disclosed herein, the ratio (B/A) is 100 Å (B/A) ≦ 2000. If it is within the range of such a content ratio (B/A), the polishing rate and the surface flatness are more suitably exhibited.

In a preferred aspect of the polishing composition disclosed herein, the diamond primary abrasive particles have an average primary particle diameter D1 _A of 10 nm or less. The diamond abrasive grain system having such an average primary particle diameter D1 _A can effectively contribute to both the polishing rate and the surface flatness.

In a preferred aspect of the polishing composition disclosed herein, the relationship between the average primary particle diameter D1 _{A of the} diamond abrasive grains and the average primary particle diameter D1 _B of the non-diamond abrasive particles satisfies the following formula: 1< (D1 _B /D1 _A ) <500. By combining the diamond abrasive grains and the non-diamond abrasive grains in such a manner as to achieve the above specific average primary particle diameter ratio, the polishing rate and the surface flatness can be achieved at a higher level.

The technique disclosed herein may be at least one of the amphoteric potential of the diamond abrasive grains of the pH of the polishing composition and the non-diamond abrasive grains and the polishing target material at a pH of the polishing composition. It is preferred to carry out the potential of the opposite polarity. Thus, by using a diamond abrasive grain, which exhibits a reverse polarity of the other potential of at least one of the non-diamond abrasive particles and the object to be polished, the polishing rate and the surface flatness can be achieved at a higher level.

In a preferred aspect of the polishing composition disclosed herein, the metastatic potential of the diamond abrasive particles at the pH of the polishing composition and the aforementioned non-diamond abrasive particles at the pH of the polishing composition. And the other potential of the material to be polished is reverse polarity. In a further preferred aspect, the amphoteric potential of the diamond abrasive grains at the pH of the polishing composition is positive, and the non-diamond abrasive grains and the polishing target material at a pH of the polishing composition are The potential of 仄 is negative. The above effect can be more satisfactorily obtained by making the potential of the diamond abrasive grains in the polishing composition positive.

In a preferred aspect of the polishing composition disclosed herein, the material to be polished has a Vickers hardness of 1500 Hv or more. Yu Yan The polishing target material is a polishing composition of a high hardness material, and the application effect of the embodiment can be more suitably exhibited.

In a preferred aspect of the polishing composition disclosed herein, the material to be polished is tantalum carbide. In the polishing composition in which the polishing target material is tantalum carbide, the application effect of the present embodiment can be more suitably exhibited.

In a preferred aspect of the polishing composition disclosed herein, the non-diamond abrasive particles comprise vermiculite particles. In the polishing using the vermiculite particles as the non-diamond abrasive grains, the effect of using a small amount of the diamond abrasive grains in combination with the non-diamond abrasive grains can be more satisfactorily exhibited.

Example

In the following, several embodiments related to the present invention are described, but the present invention is not intended to be limited to the embodiments. Further, in the following description, "%" is based on the weight unless otherwise specified.

<Modulation of polishing composition> (Example 1)

Mixed diamond abrasive grains (average primary particle diameter: 4 nm) and vermiculite abrasive grains (average primary particle diameter: 33 nm) as non-diamond abrasive grains and sodium metavanadate (NaVO ₃ ) as a grinding aid and hydrogen peroxide ( H ₂ O ₂ ) and deionized water were used to prepare a polishing composition. The content A of the diamond abrasive grains was 0.16%, the content B of the vermiculite abrasive grains was 24%, the content of NaVO ₃ was 1.8%, and the content of the H ₂ O ₂ was 1.2%. The pH of the polishing composition was 6.5.

(Example 2)

The polishing composition was prepared in the same manner as in Example 1 except that the content A of the diamond abrasive grains was set to 0.082%.

(Example 3)

The polishing composition was prepared in the same manner as in Example 1 except that the content A of the diamond abrasive grains was changed to 0.016%.

(Comparative Example 1)

The polishing composition was prepared in the same manner as in Example 1 except that the diamond abrasive grains were not used.

(Comparative Example 2)

The polishing composition was prepared in the same manner as in Example 1 except that the content A of the diamond abrasive grains was set to 0.25%, and the vermiculite abrasive grains were not used.

(Comparative Example 3)

The polishing composition was prepared in the same manner as in Example 1 except that the content A of the diamond abrasive grains was 0.77%, and the vermiculite abrasive grains were not used.

<Evaluation of grinding rate>

The prepared polishing composition is directly used as a polishing liquid, and SiC after preliminary polishing is performed on a polishing liquid containing alumina abrasive grains. The surface of the wafer was polished under the conditions described below. Further, the polishing rate was calculated in accordance with the following calculation formulas (1) and (2). The results are shown in this column of Table 1.

(1) Grinding amount [cm] = weight difference of SiC wafer before and after grinding [g] / density of SiC [g/cm ³ ] (= 3.21 g/cm ³ ) / area to be polished [cm ² ] (= 19.62cm ² )

(2) Grinding rate [nm/h] = grinding cutting amount [cm] × 10 ⁷ / grinding time (=1 hour)

[Polishing conditions]

Grinding device: Single-sided grinding device manufactured by ENGIS, Japan, type "EJ-380IN"

Polishing pad: "SUBA800" manufactured by Nitta-Haas

Grinding pressure: 300g/cm ²

Platen rotation number: 80 rev / min

Grinding time: 1 hour

Number of head rotations: 40 rpm

Supply rate of slurry: 20ml/min (overflow)

Temperature of the slurry: 25 ° C

Object to be polished: SiC wafer (conducting type: n type, crystalline type 4H 4° off) 2吋

For the diamond abrasive grains in the polishing composition used for the polishing, "ELS-Z" manufactured by Otsuka Electronics Co., Ltd. was used, and the metamorphic technology was used for the amphoteric abrasive grains and the statistic potential of the SiC particles. "DT-1200" manufactured by Dispersion Technology Inc. was measured by the aforementioned method. As a result, it was confirmed that the amphoteric potential of the diamond abrasive grains showed positive polarity (positive), and the abundance of the vermiculite abrasive grains and the SiC particles showed negative polarity (negative).

<surface roughness rms>

For the surface of the polished object after polishing, the surface roughness of the root mean square was measured using a non-contact surface shape measuring machine (trade name "NewView 5032", manufactured by Zygo Co., Ltd.) under a viewing angle of 5.6 mm × 4.2 mm. Rms[nm]. The results are shown in this column of Table 1.

As shown in Table 1, the polishing compositions of Examples 1 to 3 which were used by combining the diamond abrasive grains and the non-diamond abrasive grains at a specific content ratio were obtained, and the surface roughness rms was small while achieving a high polishing rate. Abrasive surface. In contrast, in Comparative Example 1 using only non-diamond abrasive grains, the surface roughness rms was larger than that of Examples 1 to 3, and the surface of the abrasive was flat. Insufficient. In Comparative Examples 2 and 3 in which only diamond abrasive grains were used, the surface roughness rms was also larger than that of Examples 1 to 3, and the flatness of the surface of the abrasive was insufficient. From this result, it was confirmed that by combining the diamond abrasive grains and the non-diamond abrasive grains at a specific content ratio, both the polishing rate and the surface flatness can be achieved.

The specific examples of the present invention have been described in detail above, but these are merely examples and are not intended to limit the scope of the invention. The technology described in the scope of the invention of the invention includes various modifications and changes to the specific examples exemplified above.

Industrial utilization possibility

According to the present invention, it is possible to provide a polishing composition which can achieve both a polishing rate and a surface flatness at a high level.

Claims (11)

A polishing composition for polishing a polishing target material, comprising diamond abrasive grains and non-diamond abrasive grains, wherein the content B of the non-diamond abrasive particles is relative to the diamond abrasive particles by weight The ratio of the content A (B/A) is 2 < (B/A). The polishing composition of claim 1, wherein the ratio (B/A) is 100 ≦ (B/A) ≦ 2000. The polishing composition according to claim 1 or 2, wherein the diamond abrasive grains have an average primary particle diameter D1 _A of 10 nm or less. The polishing composition according to any one of claims 1 to 3, wherein the relationship between the average primary particle diameter D1 _{A of the} diamond abrasive grains and the average primary particle diameter D1 _B of the non-diamond abrasive grains satisfies the following formula: 1<( D1 _B / D1 _A ) < 500. The polishing composition according to any one of claims 1 to 4, wherein the zeta potential of the diamond abrasive grains at the pH of the polishing composition and the aforementioned non-diamond of the pH of the polishing composition The other potential of the abrasive grains and the aforementioned polishing target material is reverse polarity. The polishing composition according to any one of claims 1 to 5, wherein the argon potential of the diamond abrasive grains at a pH of the polishing composition and the non-diamond abrasive grains at a pH of the polishing composition and The other potential of the material to be polished is reverse polarity. The polishing composition according to any one of claims 1 to 6, wherein the amphoteric potential of the diamond abrasive grains at the pH of the polishing composition is positive. The non-diamond abrasive grains at the pH of the polishing composition and the other potential of the polishing target material are negative. The polishing composition according to any one of claims 1 to 7, wherein the polishing target material has a Vickers hardness of 1500 Hv or more. The polishing composition according to any one of claims 1 to 8, wherein the material to be polished is tantalum carbide. The polishing composition according to any one of claims 1 to 9, which comprises vermiculite particles as the aforementioned non-diamond abrasive grains. A method for producing a polishing material, comprising supplying the polishing composition according to any one of claims 1 to 10 to an object to be polished, and polishing the object to be polished.