TW201434899A - Substrate wettability-promoting composition, polishing composition containing same, and method for producing substrates using same - Google Patents

Abstract

Provided is a high-quality substrate wettability-promoting composition that is free of or almost free of impurities. The present invention contains a hydrophilic component composed mainly of a cellulose derivative, and a solvent component. Impurities derived from producing the cellulose derivative are equal to or less than 0.1 mass%.

Description

Promoting substrate wettability composition, polishing composition containing the same, and manufacturing method using the same

The present invention relates to a substrate-wetting composition, a polishing composition containing the same, and a method for producing a substrate using the same.

Since the polymer compound has various properties such as mechanical properties and thermal properties which are not possessed by the low molecular compound, it has been used in a wide range of fields.

For example, when a polymer compound having a specific structure such as a cellulose derivative is dissolved in water, the surface tension is lowered, so that excellent wettability is exhibited. An aqueous solution containing a polymer compound having such wettability has been used in applications such as polishing or welding.

For example, Japanese Laid-Open Patent Publication No. 2011-97050 discloses a polishing composition comprising a diamine compound (grinding aid) having a specific structure, a compound having a polyalkylene glycol structure, and a water-soluble polymer compound. According to Japanese Laid-Open Patent Publication No. 2011-97050, it is described that wettability (hydrophilization) is improved by using a water-soluble polymer (and a compound having a polyalkylene glycol structure) in combination with the above-mentioned polishing aid. Further, Japanese Laid-Open Patent Publication No. 2011-97050 discloses that it is used in the polishing process of a silicon wafer. The aforementioned abrasive composition of high wettability. Further, the water-soluble polymer is exemplified by water-soluble polysaccharides, specifically hydroxymethylcellulose, hydroxyethylcellulose (HEC), and the like.

As described above, the aqueous solution containing the polymer compound exhibits excellent wettability. However, in Japanese Laid-Open Patent Publication No. 2011-97050, it is known that an aqueous solution of a cellulose derivative such as hydroxymethylcellulose or hydroxyethylcellulose (HEC) as a polymer compound has a large amount of impurities. Unable to obtain a high quality aqueous solution. Further, it has been found that, in particular, when an aqueous solution of a cellulose derivative containing a large amount of impurities is used for polishing a substrate, the performance of the substrate to be polished may be deteriorated.

Accordingly, it is an object of the present invention to provide a high quality substrate-wetting composition which is free or substantially free of impurities. Further, in a preferred embodiment of the present invention, it is an object of the present invention to provide a means for preventing or reducing defects of a substrate to be polished for use in polishing a substrate.

The present inventors conducted active research. As a result, it has been found that the above problems can be solved by setting the content of the impurities contained in the cellulose derivative derived from the production step to a certain value or less, and thus the present invention has been completed.

That is, the present invention relates to a substrate-wetting composition comprising a hydrophilic component having a cellulose derivative as a main component and a solvent component. In this case, the impurity derived from the production of the cellulose derivative is 0.1% by mass or less.

Moreover, the present invention relates to a polishing composition comprising fibers The pigment derivative is a hydrophilic component as a main component, a ceria particle, a basic compound, and a solvent component, and the impurity is 0.1% by mass or less.

Hereinafter, the form for carrying out the invention will be described in detail.

<Promoting substrate wettability composition>

According to one aspect of the present invention, there is provided a substrate-inducing composition (hereinafter also simply referred to as "composition") comprising a hydrophilic component containing a cellulose derivative as a main component and a solvent component. In this case, the impurity derived from the production of the cellulose derivative is 0.1% by mass or less. It may further contain a conventional additive as needed.

According to the present invention, it is possible to provide a high-quality substrate-wetting composition which is free from or almost free from impurities.

According to a particularly preferred embodiment of the present invention, a composition for preventing wettability of a substrate which prevents or reduces defects of the substrate to be polished can be provided.

In addition, in this specification, "substrate" means the one which promotes wettability by the composition of this form. The substrate differs depending on the use of the above composition. For example, when the composition is used for polishing, the substrate is exemplified by a substrate on which an inorganic insulating film such as a hafnium oxide film or a tantalum nitride film is formed, a substrate on which a polycrystalline germanium film is formed, and a germanium single crystal substrate (tantalum wafer). . In these, the substrate is preferably a germanium wafer.

[hydrophilic component]

The hydrophilic component is mainly composed of a cellulose derivative. The hydrophilic component may also contain other conventional hydrophilic compounds. At this time, the aforementioned hydrophilic component contains impurities derived from the production of the cellulose derivative. In the present specification, the term "main component" means that the total mass of the hydrophilic component is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass. Further, the upper limit is 100% by mass, but may be 99% by mass or less.

The content of the hydrophilic component is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more based on the total amount of the substrate wettability-promoting composition. In addition, the content of the hydrophilic component is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 3% by mass or less based on the total amount of the substrate wettability-promoting composition. When the content of the hydrophilic component is in the above range, it is preferred because the substrate wettability promoting composition exhibits excellent wettability.

(cellulose derivative)

The cellulose derivative means a derivative of cellulose which becomes water-soluble by replacing at least one of the hydroxyl groups of the water-insoluble cellulose with a substituent.

The cellulose is a polymer obtained by polymerizing a plurality of β-glucose molecules into a linear chain by glycoside bonding, and the constituent units of cellulose have hydroxyl groups at the C2, C3 and C6 positions. Since the aforementioned hydroxyl group forms a strong hydrogen bond between molecules, cellulose is generally insoluble in water or an organic solvent. However, by replacing at least a part of the hydrogen bond with at least a part of the hydroxyl group of the cellulose with a substituent, the cellulose derivative exhibits water solubility.

The substituent is not particularly limited, but may be exemplified by methyl or ethyl. Base, hydroxymethyl, hydroxyethyl, hydroxypropyl, carboxymethyl, carboxyethyl, and the like. When the cellulose has a plurality of substituents, the substituents may be the same or different.

Examples of specific cellulose derivatives are hydroxymethylcellulose, hydroxyethylcellulose (HEC), hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, and A. Cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose, and the like. Among these, the cellulose derivative is preferably hydroxyethyl cellulose (HEC) from the viewpoint of imparting a wettability effect. These cellulose derivatives may be used singly or in combination of two or more.

The weight average molecular weight (in terms of polyethylene oxide) of the cellulose derivative is preferably 1,000 or more, more preferably 10,000 or more, still more preferably 100,000 or more. When the weight average molecular weight of the cellulose derivative is 1,000 or more, it is preferably used for polishing, for example, because the hydrophilicity of the polished surface is improved.

Further, the weight average molecular weight (in terms of polyethylene oxide) of the cellulose derivative is preferably 2,000,000 or less, more preferably 1,500,000 or less, still more preferably 1,000,000 or less, particularly preferably 500,000 or less, and still more preferably 300,000 or less. When the weight average molecular weight of the cellulose derivative is 2,000,000 or less, it is preferable to obtain high dispersion stability when adding cerium oxide particles or the like, for example, in polishing applications.

The above cellulose derivative may be produced by itself or a commercially available product, but it is preferable to use a commercially available product from the viewpoint of cost. The commercial products are listed as AL-15, AL-15F, AH-25, SV-25F, CF-G, CF-V (Sumitomo Chemical Co., Ltd.), SP200, SP400, EP850, SE400, SE600, EE820 (made by Daicel Precision Chemical Co., Ltd.), K100, PremiumLV, E4M, Premium (made by Dow Chemical Co., Ltd.). Commercially available cellulose derivatives are generally manufactured in the industry and are generally produced by the steps of preparing cellulose and converting cellulose to cellulose derivatives.

As described above, the step of preparing cellulose comprises obtaining cellulose from natural raw materials such as wood, wheat stem, sugar cane, waste paper, kapok and the like. More specifically, it is a method of modulating pulp by physical and/or chemical action from wood, wheat stem, sugar cane, waste paper, etc., and thereby obtaining cellulose; a method of obtaining cellulose from kapok.

The step of converting the aforementioned cellulose into a cellulose derivative comprises subjecting the above-prepared cellulose to a chemical reaction. Thereby, a cellulose derivative can be produced. The aforementioned transformation method can use a suitable conventional method. For example, cellulose can be converted to a cellulose derivative by the following method. That is, the cellulose can be suspended in water, a base is added, and alkali cellulose (alkali treatment) is added, and then the reagent is added to the cellulose to obtain a cellulose derivative.

In this case, a conventional base such as sodium hydroxide or potassium hydroxide can be used as the base.

Further, the above reagents used a reagent which can obtain a desired cellulose derivative. For example, when producing hydroxyethyl cellulose (HEC), ethylene oxide or the like is used as a reagent. Further, in the case of producing cellulose acetate, acetic anhydride or the like is used as a reagent. Further, a catalyst for promoting the reaction or the like may be used as the above reagent.

The degree of substitution or the weight average molecular weight of the cellulose derivative can be controlled by appropriately changing the type of the base or the reagent, the reaction temperature, the reaction time, and the like.

Further, the cellulose derivative obtained by the chemical reaction is appropriately subjected to neutralization, purification, drying, granulation, or the like using an acid such as phosphoric acid or nitric acid.

By producing a cellulose derivative by the above method, a large amount of cellulose derivative can be produced, which is advantageous from the viewpoint of cost. Therefore, the above cellulose derivative is preferably a cellulose derivative obtained by subjecting a material derived from a natural raw material to alkali treatment, and more preferably a cellulose derivative obtained by subjecting cotton or pulp to alkali treatment.

(known hydrophilic compounds)

The above-mentioned hydrophilic compound is not particularly limited as long as it is a cellulose derivative, and examples thereof include an imine derivative such as poly(N-fluorenylalkyleneimine); polyvinyl alcohol; and modification (cation modification) Phenolic, anionically modified, or nonionic modified) polyvinyl alcohol; polyvinylpyrrolidone; polyethylene caprolactam; polyoxyalkylene groups such as polyoxyethylene; and the like Copolymer. Further, the copolymer form when the hydrophilic compound is a copolymer may be any of a block copolymer, a random copolymer, a graft copolymer, and an interactive copolymer. These conventional hydrophilic compounds may be used singly or in combination of two or more.

The weight average molecular weight (in terms of polyethylene oxide) of the conventional hydrophilic compound is preferably 1,000 or more, more preferably 10,000 or more, still more preferably 100,000 or more, and most preferably 200,000 or more. Hydrophilic combination When the weight average molecular weight of the material is 1,000 or more, for example, in polishing, the hydrophilicity of the surface to be polished can be improved, which is preferable.

Further, the weight average molecular weight (in terms of polyethylene oxide) of the conventional hydrophilic compound is preferably 2,000,000 or less, more preferably 1,500,000 or less, still more preferably 1,000,000 or less, and most preferably 500,000 or less. When the weight average molecular weight of the conventional hydrophilic compound is 2,000,000 or less, it is preferable to obtain high dispersion stability when adding cerium oxide particles or the like, for example, in polishing applications.

The content of the conventional hydrophilic compound is preferably less than 50% by mass, more preferably 40% by mass or less, still more preferably 1 to 30% by mass based on the total mass of the hydrophilic component.

[solvent component]

The solvent component is not particularly limited, but water is preferred from the viewpoints of environmental surface, ease of handling, and the like. At this time, the water is preferably one which is as free from impurities as possible. The water is preferably water which removes impurity ions by an ion exchange resin, water which removes impurities by a filter, water which removes foreign matter by distillation, or the like. These waters are listed as ion-exchanged water, pure water, ultrapure water, distilled water, and the like.

The content of the solvent component is preferably 90% by mass or more, more preferably 95% by mass or more, and still more preferably 97% by mass or more based on the total amount of the substrate wettability promoting composition. Further, the content of the solvent component is preferably 99.98 mass% or less, more preferably 99.95% by mass or less, still more preferably 99.9% by mass or less, based on the total amount of the substrate wettability promoting composition.

[impurities]

The impurities are contained in the production step of the cellulose derivative. This impurity is especially contained in the industrial production of cellulose derivatives.

The impurities are not particularly limited, and examples thereof include inorganic salts, agglomerates, and other impurities which are poorly soluble.

The poorly soluble inorganic salt is exemplified by a phosphate such as zinc phosphate, calcium hydrogen phosphate, magnesium hydrogen phosphate, magnesium phosphate or magnesium ammonium phosphate; a citrate such as calcium citrate or magnesium citrate. The poorly soluble inorganic salt is usually caused by a base treatment step in the production of a cellulose derivative, a reagent added in a step of acid neutralization, an ion contained in a solvent component (water or the like), and the like.

The agglomerates are exemplified by, for example, agglomerates of cerium oxide (SiO ₂ ); aggregates of other oxides, and the like. The agglomerate is usually a ruthenium or a group 2 element contained in a ruthenium dioxide, a solvent (water, etc.) contained in an antifoaming agent used for producing a cellulose derivative, a pulp or cotton which is used as a cellulose raw material. Or the like, and usually has an average particle diameter of about 1 to 200 μm.

As for the other impurities mentioned above, they are listed as unreacted cellulose. The unreacted cellulose is caused by unreacted unconverted material when converting cellulose into a cellulose derivative.

In the present invention, the impurity derived from the production of the cellulose derivative is 0.1% by mass or less. The content of the impurities is preferably 0.05% by mass or less, more preferably 0.01% by mass or less, and most preferably 0.005% by mass or less. When the content of the impurities is 0.1% by mass or less, the substrate wettability promoting composition is remarkably reduced. Further, the content of the impurities is a content relative to the total amount of the substrate wettability promoting composition. The lower limit of the impurity content is 0 mass %, but can also be 1 ppb or more.

Furthermore, in one embodiment of the present invention, the impurities include at least one of magnesium and calcium, and the content of at least one of the magnesium and the calcium is preferably 15 ppb or less based on the total amount of the substrate-wettable composition. More preferably, it is 10 ppb or less, more preferably 5 ppb or less, and the above-mentioned magnesium and calcium are caused by the above-mentioned poorly soluble inorganic salt. Therefore, the content of magnesium and/or calcium may sometimes be correlated with the content of the above-mentioned poorly soluble inorganic salt. The lower limit of the content of at least one of the above magnesium and calcium is 0 ppb, but may be 0.001 ppb or more. In addition, in the present specification, the content of the "magnesium content" and the "calcium content" means the content of the magnesium element and the calcium element in the composition, and is a composition in which the concentration of the hydrophilic component is adjusted to 1% by mass. The value measured by inductively coupled high frequency plasma spectrometry (ICP-AES).

<Method for Producing Substrate Wettability Composition>

According to an embodiment of the present invention, there is provided a method for producing a substrate-wetting composition comprising a hydrophilic component containing a cellulose derivative as a main component and a solvent component.

The substrate wettability promoting composition is not particularly limited and can be produced by a known method. For example, a method in which a hydrophilic component is added to a solvent component and stirred is exemplified.

In this case, the cellulose derivative contained in the substrate wettability-promoting composition of the present embodiment may contain impurities derived from the production steps. Therefore, in the above production method, the step of removing or reducing the impurities is preferably included. By this, the shape In the substrate-wettable composition, the impurities derived from the production of the cellulose derivative are 0.1% by mass or less.

The step of removing or reducing the aforementioned impurities is not particularly limited as long as it can remove or reduce impurities derived from the production of the cellulose derivative, but is preferably (A) a step of dissolving the filter cellulose derivative, and (B) The step of classifying the cellulose derivative, or (C) the step of dissolving the cellulose derivative and removing the cations contained in the impurities derived from the manufacture of the cellulose derivative.

That is, in a preferred embodiment, the method for producing a substrate wettability composition preferably comprises a step selected from the group consisting of (A) a step of dissolving a filter cellulose derivative, (B) a step of classifying a cellulose derivative, and (C) And at least one of the group consisting of the steps of dissolving the cellulose derivative and removing the cations contained in the impurities derived from the manufacture of the cellulose derivative.

The steps of dissolving the filtered cellulose derivative, (B) the step of classifying the cellulose derivative, and (C) the step of removing the cation contained in the impurity derived from the production of the cellulose derivative are explained in the following.

[Step (A): Step of dissolving and filtering the cellulose derivative]

This step is a step in which a cellulose derivative is dissolved in a solvent to prepare a cellulose derivative solution, followed by filtration. By this step, impurities derived from the production of the cellulose derivative can be removed, and at least a part of the aggregate can be preferably removed.

The solvent is not particularly limited as long as it can dissolve the cellulose derivative, but the above solvent component can be used. Furthermore, based on improving fiber It is preferred to add a basic compound to the above solvent in terms of dispersion stability of the derivative.

The pH of the cellulose derivative solution is preferably more than 7, more preferably 8 or more, still more preferably 10 or more.

The content of the cellulose derivative in the cellulose derivative solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more. When the content of the cellulose derivative is 0.01% by mass or more, a predetermined amount or more of the cellulose derivative solution can be filtered, which is preferable from the viewpoint of productivity.

Further, the content of the cellulose derivative in the cellulose derivative solution is preferably 10% by mass or less, more preferably 5% by mass or less. When the content of the cellulose derivative is 10% by mass or less, the viscosity of the cellulose derivative solution is not excessively high, and a high filtration speed can be obtained, which is preferable.

The material used in the filtration of the cellulose derivative solution is not particularly limited, but is exemplified by polypropylene, polystyrene, polyether oxime, nylon, cellulose, polyethylene terephthalate (PTFE), and polycarbonate. , glass, etc.

The filter structure is not particularly limited, and is exemplified by a depth structure, a pleat structure, a film structure, and the like.

The opening degree of the filter is not particularly limited, but is preferably 0.05 μm or more, more preferably 0.1 μm or more, and still more preferably 0.2 μm or more. When the pore opening degree of the filter is 0.05 μm or more, a high filtration speed can be obtained, which is preferable.

Further, the pore opening degree of the filter is preferably 100 μm or less, more preferably 70 μm or less, and still more preferably 50 μm or less. When the pore opening degree of the filter is 100 μm or less, the precision of filtration is improved, which is preferable.

The filtration method may be any of natural filtration, suction filtration, pressure filtration, and centrifugal filtration at atmospheric pressure.

This step can be performed more than 2 times. At this time, it is preferable to appropriately change conditions such as the opening degree of the filter. For example, the first dissolution filtration system uses a filter having a larger pore opening degree to remove coarse particles, and the second dissolution filtration system uses a filter having a narrow pore opening degree to remove fine particles. By performing two or more dissolution filtrations, impurities can be removed more effectively.

[Step (B): Step of classifying cellulose derivative]

This step is a step of classifying the cellulose derivative. By this step, impurities derived from the production of the cellulose derivative can be removed, and it is preferably a poorly soluble inorganic salt, an agglomerate, an unreacted cellulose, and more preferably at least a part of a poorly soluble inorganic salt or agglomerate. In the present specification, the term "classifying" means separating impurities having a certain particle diameter or more from a cellulose derivative containing impurities. This classification is usually carried out using a classification device.

The classification device is exemplified by a sieve separation device such as a vibration sifter, a low-mesh screen, an electromagnetic sieve, a dry separation device such as a micro-separator or a cyclone, and a decanter ( A wet classifier such as a decanter type centrifugal separator, a liquid blast device, a drag classifier, or the like. These classifying devices can also be combined as appropriate.

This step can also be performed more than 2 times. In this case, it is preferable to appropriately change the conditions of the type of the sieve machine, the classification method, and the like. For example, the first classification is performed by using a blower, and the second classification is by using a vibration sieve machine. Method of grading, etc. The decomposing of the cellulose derivative can also be carried out between the fractions. By performing classification of more than 2 times, impurities can be removed more effectively.

[Step (C): Step of removing cations contained in impurities derived from the production of cellulose derivatives]

This step is a step of removing the cation after dissolving the cellulose derivative in a solvent to prepare a cellulose derivative solution. By this step, impurities derived from the production of the cellulose derivative can be removed, preferably at least a part of the poorly soluble inorganic salt.

The type of the solvent and the content of the cellulose derivative in the cellulose derivative solution are the same as those in the step of dissolving the filtered cellulose derivative, and thus the description thereof will be omitted.

The method of removing the cation is not particularly limited, and an ion exchange method can be utilized. The ion exchange method is exemplified by a method of passing a cellulose derivative solution through a column packed with an ion exchange resin and separating the cellulose derivative from impurities derived from the cellulose derivative.

The ion exchange resin to be used is not particularly limited, and examples thereof include a strongly acidic cation exchange resin and a weakly acidic cation exchange resin.

The exchange group which the aforementioned strongly acidic cation exchange resin has is exemplified by a sulfonic acid group or the like.

The exchange group of the weakly acidic cation exchange resin is exemplified by a carboxyl group, a phenolic hydroxyl group or the like.

Commercially available products can be used as the ion exchange resin, and the commercial products are listed as Diaion (trademark) series (manufactured by Mitsubishi Chemical Corporation), Amberlite. (trademark), Anberjet (trademark) (made by Organo Co., Ltd.), and the like.

This step can also be performed more than 2 times. In this case, conditions such as the pH of the cellulose derivative solution or the type of the ion exchange resin are preferably appropriately changed. For example, a low pH (weakly basic) cellulose derivative is used in the first ion exchange, and the pH of the cellulose derivative solution is adjusted before the second ion exchange to prepare a high pH (strong alkaline). After the cellulose derivative solution, the second ion exchange method or the like is performed. By performing ion exchange twice or more, impurities can be removed more effectively.

Moreover, it is preferred to remove the anion simultaneously with the removal of the cation. It is better to remove the anions after the cations are removed. The anion can be removed by residual cation bonding which is slightly present after the cation removal step, thereby reducing the possibility of formation of poorly soluble inorganic substances.

The ion exchange resin used for removing the anion is not particularly limited, and examples thereof include a strongly basic anion exchange resin type I, a strongly basic anion exchange resin type II, and a weakly basic anion exchange resin.

The exchange group which is the type I of the strongly basic anion exchange resin is exemplified by a trimethylammonium group or the like.

The exchange group which the above-mentioned strongly basic anion exchange resin type II has is exemplified by a dimethylethanolammonium group or the like.

The exchange group which the aforementioned weakly basic anion exchange resin has is exemplified by a tertiary amine group or the like.

The above steps (A) to (C) may be carried out separately or in combination of two or more steps. At this time, when combining two or more steps, you can follow any The order is carried out. That is, it can be carried out in the order of steps (A) - (B), in the order of steps (A) - (C), and in the order of steps (A) - (B) - (C), It is carried out in the order of step (A) - step (C) - step (B), and in the order of step (B) - step (A) - step (C). Among these, it is preferred to carry out the steps (B) to (A) to (C).

Further, each of the above steps may be performed at 2 degrees or more. Therefore, step (A) - step (B) - step (A) - step (C), step (B) - step (B) - step (A) - step (C), step (B) - step ( B) - Step (A) - Step (C) - Step (C) and the like are carried out in various orders and combinations.

Further, when two or more steps (A) to (C) are combined, it is a matter of course that conventional treatment such as pulverization treatment, pH adjustment treatment or other purification treatment may be performed between the respective steps.

By the step of removing or reducing the aforementioned impurities as described above, a composition derived from the production of the cellulose derivative can be obtained in an amount of 0.1% by mass or less.

<Polishing composition>

The above-mentioned substrate-wetting composition is used for various purposes. For example, it is used in applications such as polishing, cleaning after polishing, and welding. Among these, it is preferably used in cleaning applications after polishing and polishing. Hereinafter, the above composition will be specifically described for the purpose of polishing.

According to an embodiment of the present invention, there is provided a method comprising the present invention A polishing composition for entering the substrate wettable composition. According to the polishing composition of the present embodiment, the substrate to be polished (object to be polished) has excellent performance.

In the past, the polishing composition containing a cellulose derivative, particularly an industrial cellulose derivative, may have different properties depending on the batch of the cellulose derivative to be used. As a result, an object to be polished having different properties can be obtained by replacing a batch of the cellulose derivative, and as a result, it is particularly affected by the field of semiconductors requiring precision of the nanometer level.

The results of the above-described performance changes were examined in detail, and it was found that Light Point Defects (LPD) occurred on the surface of the object to be polished with low performance. Moreover, as a result of a more detailed review, it was determined that the number of the LPD differs depending on the batch of the cellulose derivative.

The present inventors have found that the occurrence of LPD is related to the impurities contained in the cellulose derivative, and it has been found that the occurrence of LPD can be prevented or suppressed by removing or reducing the impurities.

The polishing composition of the present aspect comprises the above-mentioned substrate-wetting composition, cerium oxide particles, and a basic compound.

More specifically, the polishing composition of the present embodiment contains a hydrophilic component containing a cellulose derivative as a main component, cerium oxide particles, a basic compound, and a solvent component. In addition, other additives may also be included as needed. In this case, the polishing composition contains impurities (hereinafter also referred to as "impurities for polishing composition") of 0.1% by mass or less, preferably 0.05% by mass or less, more preferably 0.01% by mass or less, and most preferably 0.005 mass% under. Further, the lower limit of the impurity content of the polishing composition is 0% by mass, but may be 1 ppb or more. Further, the impurity content of the polishing composition is based on the total amount of the polishing composition.

Furthermore, in one embodiment of the present invention, the impurity of the polishing composition contains at least one of magnesium and calcium, and the content of at least one of the magnesium and calcium is preferably 10 ppb based on the total amount of the polishing composition. Hereinafter, it is preferably 5 ppb or less. Further, the lower limit of the content of at least one of the above magnesium and calcium is 0 ppb, but may be 0.001 ppb or more. Further, the method for measuring the magnesium content and the calcium content in the polishing composition is the same as in the case of promoting the substrate wettability composition.

The pH of the polishing composition is preferably 8 or more, more preferably 8.5 or more, still more preferably 9 or more. When the pH of the polishing composition is 8 or more, the function of the chemical polishing surface can be improved, and the dispersibility of the cerium oxide particles or the like can be improved.

Further, the pH of the polishing composition is preferably 12.5 or less, more preferably 12 or less, still more preferably 11.5 or less. When the pH of the polishing composition is 12.5 or less, the smoothness of the polished surface can be improved, which is preferable. The pH of the polishing composition can be adjusted by using a basic compound, a pH adjusting agent, and the like described later.

Hereinafter, each component contained in the polishing composition will be described in detail.

[hydrophilic component]

As a hydrophilic component, due to the use of the above cellulose derivatives or Since a hydrophilic compound or the like is known, the description thereof is omitted here.

Since the impurities derived from the production of the cellulose derivative contained in the substrate wettable composition are 0.1% by mass or less, the impurities of the polishing composition are also 0.1% by mass or less. As a result, by using the polishing composition of the present embodiment, occurrence of LPD of the object to be polished can be prevented or suppressed, and foreign matter on the polishing surface can be prevented from remaining.

The content of the hydrophilic component in the polishing composition is preferably 0.002% by mass or more, more preferably 0.004% by mass or more, still more preferably 0.006% by mass or more, and most preferably 0.01% based on the total amount of the polishing composition. More than % by mass. When the content of the hydrophilic component in the polishing composition is 0.002% by mass or more, the wettability of the polished surface can be further improved, which is preferable.

In addition, the content of the hydrophilic component in the polishing composition is preferably 0.5% by mass or less, more preferably 0.2% by mass or less, and still more preferably 0.1% by mass or less based on the total amount of the polishing composition. When the content of the hydrophilic component in the polishing composition is 0.5% by mass or less, the dispersion stability of the polishing composition can be improved, which is preferable.

[cerium oxide particles]

The cerium oxide particles have a function of mechanically grinding the surface to be polished.

The cerium oxide particles are not particularly limited, and examples thereof include colloidal cerium oxide, fumed cerium oxide, and sol-gel cerium oxide. In the above, the cerium oxide particles are preferably colloidal cerium oxide or fumes from the viewpoint of preventing or suppressing scratches on the polishing surface when the ruthenium substrate is used as the substrate. Cerium dioxide is better as colloidal cerium oxide. Further, the cerium oxide particles preferably contain no aggregates of cerium oxide derived from one of the impurities produced by the cellulose derivative. Even if it is contained, it is 0.1 mass % or less. The agglomerates of the cerium oxide are also described by the average particle diameter of the above-mentioned impurities, and have an extremely large particle diameter in comparison with the average primary particle diameter or the average secondary particle diameter of the cerium oxide particles described later.

The cerium oxide particles can also be surface modified. Since the zeta potential is relatively large by the surface modification of the cerium oxide particles, the dispersibility of the polishing composition is improved, and the storage stability of the polishing composition is improved.

The surface-modified cerium oxide particles are preferably cerium oxide particles (preferably colloidal cerium oxide) which is surface-modified with an organic acid. In this case, the organic acid is not particularly limited, and examples thereof include a sulfonic acid, a carboxylic acid, and a phosphoric acid.

The method of surface-modifying the cerium oxide is not particularly limited, and a conventional method is suitably applied. For example, when the colloidal ceria is surface-modified with a sulfonic acid, it can be carried out by the method described in "Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups" (Chem. Commun. 246-247 (2003)). Specifically, after coupling a decane coupling agent having a thiol group such as 3-mercaptopropyltrimethoxydecane to a colloidal cerium oxide, the thiol group is oxidized with hydrogen peroxide to obtain a surface modification by a sulfonic acid. Colloidal cerium oxide. Moreover, "Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica" may be utilized for the surface modification of colloidal cerium oxide with a carboxylic acid. Gel" (Chemistry Latters, 3, 228-229 (2000)). Specifically, after coupling a photoreactive 2-nitrobenzyl ester decane coupling agent to colloidal cerium oxide, By illuminating, a colloidal cerium oxide modified by a carboxylic acid surface can be obtained.

These cerium oxide particles may be used singly or in combination of two or more.

The average primary particle diameter of the cerium oxide particles is preferably 5 nm or more, more preferably 10 nm or more, and still more preferably 20 nm or more. When the average primary particle diameter of the cerium oxide particles is 5 nm or more, the polishing rate of the ruthenium substrate can be improved, which is preferable.

Further, the average primary particle diameter of the cerium oxide particles is preferably 100 nm or less, more preferably 70 nm or less, still more preferably 50 nm or less. When the average primary particle diameter of the cerium oxide particles is 100 nm or less, the dispersion stability of the polishing composition can be improved, which is preferable. In the present specification, the value of the "average primary particle diameter of the cerium oxide particles" is the value of the specific surface area measured by the BET method using Flow Sorb II 2300 (manufactured by Micrometrics Co., Ltd.).

The average secondary particle diameter of the cerium oxide particles is preferably 10 nm or more, more preferably 20 nm or more, and still more preferably 30 nm or more. When the average secondary particle diameter of the cerium oxide particles is 10 nm or more, a high polishing rate can be obtained at the time of polishing, which is preferable.

Further, the average secondary particle diameter of the cerium oxide particles is preferably 200 nm or less, more preferably 150 nm or less, still more preferably 100 nm or less. When the average secondary particle diameter of the cerium oxide particles is 200 nm or less, the polishing can be improved. It is preferred to use the dispersion stability of the composition. In the present specification, the value of the "average secondary particle diameter of the cerium oxide particles" is measured by a dynamic light scattering method using FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.).

The average value of the aspect ratio (long diameter/short diameter ratio) of the cerium oxide particles is preferably 1.0 or more, more preferably 1.05 or more, still more preferably 1.1 or more. When the average value of the aspect ratio of the cerium oxide particles is 1.0 or more, a high polishing rate can be obtained at the time of polishing, which is preferable.

Further, the average value of the aspect ratio (long diameter/short diameter ratio) of the cerium oxide particles is preferably 3.0 or less, more preferably 2.0 or less, still more preferably 1.5 or less. When the average value of the aspect ratio of the cerium oxide particles is 3.0 or less, it is preferable to prevent or reduce the scratches generated on the polished surface. In addition, in the present specification, the "average aspect ratio (longitudinal diameter/short diameter ratio)" is calculated by the following method. That is, 200 particles were observed using a scanning electron microscope (SEM), and the smallest rectangle circumscribing the respective particle images was drawn. Next, the length (length of the long diameter) of the long side of the obtained rectangle was measured with respect to the length of the short side (the value of the short diameter), and the average value was calculated and obtained.

The true specific gravity of the cerium oxide particles is not particularly limited, and is preferably 1.5 or more, more preferably 1.6 or more, and still more preferably 1.7 or more. When the true specific gravity of the cerium oxide particles is 1.5 or more, a high polishing rate can be obtained at the time of polishing, which is preferable.

Further, the true specific gravity of the cerium oxide particles is preferably 2.2 or less, more preferably 2.1 or less. In addition, in the present specification, the value of "true specific gravity" is determined by the mass of the particles when they are dried, and when the known capacity of ethanol is filled therein. The value of the quality calculation.

The content of the cerium oxide particles in the polishing composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and still more preferably 0.3% by mass or more based on the total amount of the polishing composition. When the content of the cerium oxide particles in the polishing composition is 0.1% by mass or more, the surface processing property such as the polishing rate of the surface to be polished can be improved.

In addition, the content of the cerium oxide particles in the polishing composition is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 3% by mass or less based on the total amount of the polishing composition. When the content of the cerium oxide particles in the polishing composition is 10% by mass or less, the dispersion stability of the polishing composition can be improved, and the residue of the cerium oxide particles on the polished surface can be reduced.

[basic compound]

The basic compound has a function of chemically polishing the surface to be polished. Moreover, it has the function of increasing the polishing speed. Further, it has a function of improving the dispersion stability of the polishing composition.

The basic compound is not particularly limited, and examples thereof include ammonia, an amine, a quaternary ammonium hydroxide or a salt, an alkali metal hydroxide or a salt. In this case, the salt is exemplified by a carbonate, a hydrogencarbonate, a sulfate, an acetate or the like.

Specific examples of the amine are exemplified by methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylene Diamine, di-ethyltriamine, tri-ethyltetramine, anhydrous piperidine, piperidine hexahydrate, 1-(2-aminoethyl)piperidine, N-methyl Piperidine, hydrazine, etc.

The quaternary ammonium hydroxide or salt is exemplified by tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, ammonium hydrogencarbonate, ammonium carbonate and the like.

The hydroxide or salt of an alkali metal is exemplified by potassium hydroxide, potassium carbonate, potassium hydrogencarbonate, potassium sulfate, potassium acetate, potassium chloride, sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, sodium sulfate, sodium acetate, and chlorination. Sodium and so on.

Among the above basic compounds, ammonia, a quaternary ammonium hydroxide or a salt, an alkali metal hydroxide or a salt is preferred, and more preferably ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide or carbonic acid. Ammonium hydroxide, ammonium carbonate, potassium hydroxide, potassium carbonate, potassium hydrogencarbonate, sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, and more preferably ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide potassium hydroxide Sodium hydroxide, preferably ammonia, tetramethylammonium hydroxide, and preferably ammonia.

These basic compounds may be used singly or in combination of two or more.

The content of the basic compound in the polishing composition is preferably 0.001% by mass or more, more preferably 0.002% by mass or more, still more preferably 0.003% by mass or more, and most preferably 0.004, based on the total amount of the polishing composition. More than % by mass. When the content of the basic compound in the polishing composition is 0.001% by mass or more, the chemical polishing action of the surface to be polished can be improved, and the dispersion stability of the polishing composition can be improved, which is preferable.

Further, the content of the basic compound in the polishing composition is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, still more preferably 0.2% by mass or less, based on the total amount of the polishing composition. It is 0.1% by mass or less. The content of the basic compound in the polishing composition is 1.0% by mass. In the case of the lower side, the smoothness of the surface to be polished can be improved, which is preferable.

[solvent component]

Since the solvent component can use the above, the description is omitted here.

[Impurity of the composition for polishing]

The impurities of the polishing composition are exemplified by impurities derived from the production of the cellulose derivative and/or impurities derived from at least one selected from the group consisting of cerium oxide particles, basic compounds, and solvent components. In other words, the impurities of the polishing composition are different from the impurities (the impurities derived from the production of the cellulose derivative) in the substrate wettability promoting composition.

The impurities derived from the production of the cellulose derivative are exemplified above.

The at least one impurity selected from the group consisting of cerium oxide particles, a basic compound, and a solvent component is exemplified by, for example, agglomeration of cerium oxide particles in the production process of the polishing composition. Agglomerates of cerium oxide, and the like.

[Other additives]

The additive contained in the polishing composition is not particularly limited, and examples thereof include abrasive grains, a pH adjuster, a surfactant, an organic acid or a salt thereof, an inorganic acid or a salt thereof, a chelating agent, a preservative, and an antifungal agent.

(abrasive grain)

The abrasive grains are cerium oxide particles and mechanically ground to become abrasive The function of the face of the object.

The abrasive grains are exemplified by inorganic particles other than cerium oxide particles, organic particles, and organic-inorganic composite particles.

The inorganic particles other than the cerium oxide particles are exemplified by alumina (Al ₂ O ₃ ) particles, cerium oxide (CeO ₂ ) particles, titanium oxide (TiO ₂ ) particles, tantalum nitride particles, cerium carbide particles, and boron nitride particles. Wait.

The organic particles are exemplified by polymethyl methacrylate (PMMA) particles and the like.

The content of the abrasive grains is not particularly limited and may be appropriately set depending on the use of the polishing composition or the like.

(pH adjuster)

The pH adjuster has a function of adjusting the pH of the polishing composition. By adjusting the pH, the polishing rate or the dispersibility of the cerium oxide particles can be controlled.

The pH adjusting agent is not particularly limited and is exemplified by a conventional acid, a base, or a salt thereof.

The acid is exemplified by inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid; formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-Hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid , glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid , tartaric acid, citric acid, lactic acid, glycolic acid, 2-furan An organic acid such as 2-furancarboxylic acid, 2,5-furandicarboxylic acid, 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, methoxyacetic acid, methoxyphenylacetic acid or phenoxyacetic acid. Among these, the pH adjuster is preferably sulfuric acid, nitric acid, phosphoric acid, glycolic acid, succinic acid, maleic acid, citric acid, tartaric acid, malic acid, glutaric acid or itaconic acid.

The base is exemplified by an amine such as an aliphatic amine or an aromatic amine, an organic base, or a hydroxide of an alkaline earth metal, in addition to the above basic compound. Among these, the base is preferably potassium hydroxide or ammonia from the viewpoint of easiness of availability.

Further, a salt such as an ammonium salt or an alkali metal salt described above may be used in place of or in combination with the above acid or base as a pH adjuster. In particular, when a weak acid and a strong base, a strong acid and a weak base, a combination of a weak acid and a weak base are used, a buffering effect of pH can be obtained.

The amount of the pH adjuster to be added is not particularly limited, and can be appropriately set so that the polishing composition has a desired pH.

(surfactant)

The surfactant has a function of suppressing the roughness of the polished surface. By suppressing the roughness of the polished surface, the turbidity of the polished surface can be reduced. Further, since the polishing composition of the present embodiment contains a basic compound which is chemically polished, it is possible to more effectively suppress the roughness of the polished surface by adding a surfactant.

The surfactant is not particularly limited and is exemplified by a nonionic or ionic surfactant having a weight average molecular weight of less than 1,000.

The aforementioned nonionic surfactants are exemplified by oxyalkylene polymerization. , polyoxyalkylene alkyl adducts, and the like.

The above-mentioned oxyalkylene polymer is exemplified by polyethylene glycol, polypropylene glycol or the like.

The polyoxyalkylene alkyl adducts are exemplified by polyoxyethylene ethyl propyl ether, polyoxyethylene ethyl butyl ether, polyoxyethylene ethyl pentyl ether, polyoxyethylene ethyl hexyl ether, polyoxyethylene P-octyl ether, polyoxyethylene ethyl-2-ethylhexyl ether, polyoxyethyl ether, polyoxyethyl ether, polyoxyethylene ethyl isodecyl ether, polyoxyethylene Tridecyl ether, polyoxyethylene ethyl lauryl ether, polyoxyethylene ethyl cetyl ether, polyoxyethylene ethyl stearyl ether, polyoxyethylene ethyl isostearyl ether, polyoxyl extension Polyoxyethylene ethyl ether such as ethyl oleyl ether; polyoxyethylene ethyl phenyl ether, polyoxyethyl octyl phenyl ether, polyoxyethyl phenyl ether, polyoxyethylene Polyoxyethylene ethyl phenyl ether such as dodecyl ether, polyoxyethylidene styrene phenyl ether; polyoxyethylene ethyl laurylamine, polyoxyethylene ethyl stearylamine, poly Polyoxyethylene ethylamine, such as oxygen-extension ethyl oleylamine; polyoxyethylene ethyl decylamine such as polyoxyethylene ethyl stearylamine, polyoxyethylene ethyl decylamine; polyoxyalkylene Ethyl monolaurate, polyoxyethylidene monostearate, polyoxyethylene ethyl stearate Polyoxyethylene ethyl oleate, polyoxyethylidene dioleate, polyoxyethylidene ether fatty acid ester; polyoxyethylene ethyl glyceryl ether fatty acid ester; monolauric acid polyoxyethylene ethyl sorbitol Sugar alcohol anhydride, monopalmitic acid polyoxyethylene ethyl sorbitan, monostearic acid polyoxyethylene sorbitan, monooleic acid polyoxyethylene sorbitan, trioleic acid polyoxygen Polyoxyethylene sorbitan fatty acid esters such as ethyl sorbitan, tetraoleic acid polyoxyethylene sorbitan, etc.; polyoxylated ethyl castor oil, polyoxyethylene ethyl hardened castor oil Such as castor oil; polyoxy-extension ethyl polyoxypropyl propyl copolymer Polymer, etc.

Among the above surfactants, in order to reduce the foaming property, it is easy to prepare the polishing composition at the time of preparation or use, and it is preferable to use a nonionic surfactant from the viewpoint of easy pH adjustment. .

These surfactants may be used singly or in combination of two or more.

(Organic acid or its salt ‧ mineral acid or its salt)

The organic acid or a salt thereof, the inorganic acid or a salt thereof has a function of improving the hydrophilicity of the polished surface.

The organic acid is not particularly limited, and is exemplified by fatty acids such as formic acid, acetic acid, and propionic acid; aromatic carboxylic acids such as benzoic acid and phthalic acid; citric acid, oxalic acid, tartaric acid, malic acid, maleic acid, fumaric acid, and succinic acid. Such as polycarboxylic acid; organic sulfonic acid; organic phosphoric acid and the like.

The organic acid salt is not particularly limited, and examples thereof include alkali metal salts such as sodium salts and potassium salts of the above organic acids; ammonium salts and the like.

The inorganic acid is not particularly limited, and examples thereof include sulfuric acid, nitric acid, hydrochloric acid, and carbonic acid.

The inorganic acid salt is not particularly limited, and examples thereof include an alkali metal salt such as a sodium salt or a potassium salt of the above inorganic acid; an ammonium salt;

Among these, an ammonium salt of an organic acid or an inorganic acid is preferably used from the viewpoint of suppressing metal contamination of the abrasive article.

The organic acid or a salt thereof, the inorganic acid or a salt thereof may be used singly or in combination of two or more.

(chelating agent)

The chelating agent has a function of preventing or suppressing metal contamination of the abrasive article by forming a complex compound with metal impurities to capture metal impurities.

The chelating agent is not particularly limited, and examples thereof include an aminocarboxylic acid-based chelating agent and an organic phosphonic acid-based chelating agent.

The above-mentioned aminocarboxylic acid-based chelating agent is exemplified by ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrogen triacetic acid, sodium nitrotriacetate, ammonium nitroacetate, hydroxyethylethylenediaminetriacetic acid, and hydroxy group. Ethyl ethylenediamine triacetate, diamethylenetriamine pentaacetic acid, sodium diethylenediaminepentaacetate, triamethylenetetraamine hexaacetic acid, sodium triamethylenetetraacetate, and the like.

The aforementioned organic phosphonic acid chelating agents are exemplified by 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotris(methylenephosphonic acid), ethylenediamine oxime (Asian). Methylphosphonic acid), diethylenetriamine penta (methylene phosphonic acid), triamethylenetetramine hexa (methylene phosphonic acid), ethane-1,1-diphosphonic acid, ethane-1, 1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, ethane-1-hydroxy-1,1,2-triphosphonic acid, ethane-1,2-dihydroxy- 1,2-diphosphonic acid, methane hydroxyphosphonic acid, 2-phosphinobutane-1,2-dicarboxylic acid, 1-phosphinobutane-2,3,4-tricarboxylic acid, α-methylphosphine Succinic acid and the like.

Among the above chelating agents, an organic phosphonic acid-based chelating agent is preferred, and ethylenediamine hydrazine (methylene phosphonic acid) is more preferred.

These chelating agents may be used singly or in combination of two or more.

(preservatives, anti-mold agents)

The preservative ‧ antifungal agent is not particularly limited, and is exemplified by isomethylthiazoline such as 2-methyl-4-isothiazolin-3-one or 5-chloro-2-methyl-4-isothiazolin-3-one. Compounds; p-hydroxybenzoic acid esters; phenoxyethanol and the like.

The above-mentioned preservatives and antifungal agents may be used singly or in combination of two or more.

<Method for Producing Composition for Grinding>

The method for producing the polishing composition is not particularly limited, and a conventional method can be applied. As a specific example, a hydrophilic component, a cerium oxide particle, a basic compound, and an arbitrary additive can be produced by sequentially adding to a solvent component. Further, the cerium oxide particles and the basic compound may be added to the solvent component, and a solution containing a hydrophilic component and a solvent component (promoting the substrate wettability component) may be added to the mixed liquid to prepare a polishing composition. Things. Among these, a polishing composition is preferably produced by the latter method. That is, in a preferred embodiment, the method for producing a polishing composition includes a step of adding a cerium oxide particle and a basic compound to a solvent component to prepare a mixed solution, and a solution containing a hydrophilic component and a solvent component ( A step of adding a substrate wettability composition to the mixed liquid. In this case, any of the additives may be added to the mixed liquid or may be added to the substrate wettable composition. Hereinafter, a manufacturing method according to the above preferred embodiment will be described.

[Step of adding cerium oxide particles and a basic compound to a solvent component to prepare a mixed solution]

This step is to prepare a mixed solution.

The mixed solution contains cerium oxide particles, a basic compound, and a solvent component. It may also contain any additives as needed.

The content of the cerium oxide component in the mixed liquid is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more based on the total amount of the mixed liquid. When the content of the cerium oxide particles is 1% by mass or more, it is preferable to adjust the content of the cerium oxide particles in the polishing composition to be produced.

Further, the content of the cerium oxide particles in the mixed liquid is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less based on the total amount of the mixed liquid. When the content of the cerium oxide particles is 50% by mass or less, aggregation of the cerium oxide particles can be prevented, which is preferable.

The content of the basic compound in the mixed liquid is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more based on the total amount of the mixed liquid. When the content of the basic compound is 0.01% by mass or more, aggregation of the cerium oxide particles can be suppressed, which is preferable.

Further, the content of the basic compound in the mixed liquid is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 3% by mass or less based on the total amount of the mixed liquid. When the content of the basic compound is 10% by mass or less, it is preferred to adjust the content of the basic compound in the polishing composition to be produced.

The pH of the above mixed liquid is preferably more than 7 (basic), more preferably 8 or more, still more preferably 9 or more. When the pH exceeds 7 (basic), it is possible to suppress the substrate wettability composition from being added to a mixed liquid containing cerium oxide particles or the like. Coagulation of cerium oxide particles. Thereby, it is preferable to increase the effect of volatilization to improve the dispersion stability of the finally obtained polishing composition.

Further, the pH of the mixed liquid is preferably 12 or less, more preferably 10.5 or less. When the pH is 12 or less, it is preferred to suppress the dissolution of the cerium oxide particles.

The content of any additive can be appropriately set depending on the desired performance or the like.

[Step of adding a solution containing a hydrophilic component and a solvent component (promoting the substrate wettability composition) to the mixed solution]

In this step, a solution containing a hydrophilic component and a solvent component (a substrate-wetting composition is added) is added to the mixed solution prepared in the above step. In this case, the solution containing the hydrophilic component and the solvent component (the substrate wettability promoting composition) may optionally contain any additives.

When the mixed liquid exceeds 7, the cerium oxide particles in the mixed liquid have high dispersion stability, so that it is possible to prevent or suppress the addition of a solution containing a hydrophilic component and a solvent component (promoting the substrate wettability composition). Coagulation of cerium oxide.

The speed at which the solution containing the hydrophilic component and the solvent component (the substrate wettability-promoting composition) is put into the mixed solution is preferably 0.1 mL/min or more, more preferably 1 mL/min or more, and more preferably 1 L of the mixed solution. Good is 5mL / min or more. When the input speed is 0.1 mL/min or more, the production efficiency of the polishing composition can be improved, which is preferable.

In addition, the aforementioned solution containing a hydrophilic component and a solvent component (promoting The substrate wettability composition) is preferably used in an amount of 500 mL/min or less, more preferably 100 mL/min or less, and more preferably 50 mL/min or less, based on 1 L of the mixed liquid. When the input speed is 500 mL/min or less, it is preferable to suppress the aggregation of cerium oxide.

The polishing composition can also be prepared by diluting a stock solution of the polishing composition with water. The dilution ratio in this case is preferably 2 times or more, more preferably 5 times or more, and still more preferably 10 times or more. When the dilution ratio is twice or more, the transportation cost of the stock solution for the polishing composition becomes relatively low, and the storage place can be saved, which is preferable.

Further, the above dilution ratio is preferably 100 times or less, more preferably 50 times or less, still more preferably 40 times or less. When the dilution ratio is 100 times or less, it is easy to maintain the stability of the polishing composition stock solution.

The polishing composition of the present embodiment is characterized in that the impurities (impurities of the polishing composition) are 0.1% by mass or less as described above. Therefore, when the above-mentioned polishing composition is produced, it is necessary to appropriately set the raw materials, the production conditions, and the like, and the impurities of the polishing composition are made 0.1% by mass or less.

The means for setting the impurity of the polishing composition to 0.1% by mass or less is not particularly limited, and it is exemplified to remove or reduce the cellulose derivative derived by using at least one step including the above steps (A) to (C). A method for using a cellulose derivative or a polishing composition after the production of impurities as a raw material; and preventing the second step by controlling the order of the input of the cerium oxide particles, the input speed, the pH of the liquid to be charged, the pH after the input, and the like A method of agglomerating cerium oxide particles, and the like. Moreover, when the polishing composition is produced by using the cellulose derivative produced in the step (C) as a raw material, the polishing composition is preferably reduced. The tendency of the content of at least one of magnesium and calcium contained in the polishing composition.

<Method of Manufacturing Substrate>

The above polishing composition can be used for substrate polishing. The substrate is exemplified by a substrate on which an inorganic insulating film such as a ruthenium oxide film or a tantalum nitride film is formed, a substrate on which a polysilicon film is formed, a germanium wafer, or the like. In these cases, since the polishing composition of the present embodiment contains cerium oxide particles, it is preferable to use a substrate on which polycrystalline germanium is formed or a germanium wafer as a substrate, and it is preferable to use a germanium wafer. Thereby, a high performance germanium wafer can be manufactured.

That is, according to one aspect of the present invention, a method of manufacturing a tantalum wafer is provided. The method for manufacturing a tantalum wafer includes polishing a tantalum wafer with a polishing composition.

In most cases, a germanium single crystal ingot is formed by a Cz method (Czochralski method) or a Fz method (Floating Zone method), and is processed and manufactured. In this case, the polishing composition can be subjected to a rough polishing step (primary polishing, secondary polishing) for planarizing the surface of the substrate from which the single crystal ingot is cut into a disk shape, and further removing the rough polishing step. The final polishing step is performed by mirroring the fine concavities and convexities on the surface of the substrate. In order to obtain an object to be polished having excellent properties, the above-mentioned polishing composition is preferably used in the final polishing step.

The polishing apparatus to be used is not particularly limited, and a holder for holding a substrate having an object to be polished or the like, a motor capable of changing the number of revolutions, and the like, and a polishing platen to which a polishing pad (polishing cloth) can be attached can be used. General grinding equipment.

The polishing pad is not particularly limited, and a general nonwoven fabric, a polyurethane, a porous fluororesin or the like can be used. At this time, the polishing pad is preferably processed by a groove which allows the polishing liquid to accumulate.

The polishing conditions are not particularly limited and can be appropriately set. For example, the number of revolutions of the grinding platen is preferably from 10 to 500 rpm. Further, the pressure (grinding pressure) applied to the substrate having the object to be polished is preferably from 0.5 to 10 psi.

The method of supplying the polishing composition to the polishing pad is not particularly limited, and for example, a method of continuously supplying the pump or the like can be employed. In this case, the amount of supply is not limited, but it is preferred to cover the surface of the polishing pad with the polishing composition of the present invention.

When the substrate is polished using the polishing composition, the polishing composition used in the polishing can be recovered once and used again for polishing the substrate. The method of reusing the polishing composition is exemplified by a method in which the polishing composition discharged from the polishing apparatus is collected in a tank and circulated to the re-grinding apparatus. Further, by using the polishing composition, the environmental load can be reduced by reducing the amount of the polishing composition discharged as the waste liquid, and the substrate polishing can be suppressed by reducing the amount of the polishing composition to be used. It is useful in terms of cost.

Further, when the polishing composition is further used, it is preferred to add a part or all of each of the components such as the hydrophilic component which is consumed by polishing to the loss, as a composition adjusting agent. Further, the method for preparing the hydrophilic component can be appropriately referred to the description of the method for producing the polishing composition.

The polishing composition can also be applied to a polishing composition for obtaining an abrasive article other than a tantalum wafer. Specific examples of abrasive products other than silicon wafers It is a metal such as stainless steel, a plastic substrate, a glass substrate, a quartz substrate, or the like. Further, the components contained in the polishing composition may be appropriately changed depending on the polishing product.

[Examples]

Hereinafter, the present invention will be described by way of examples, but the invention is not limited thereto.

(Comparative Example 1)

First, a commercially available hydroxyethyl cellulose (HEC) powder (weight average molecular weight: 250,000 (in terms of polyethylene oxide), product name: SE-400, manufactured by Daicel Precision Chemical Co., Ltd.) was prepared.

Water was added thereto so that the concentration of HEC became 1% by mass, and the substrate wettability promoting composition was produced by stirring.

(Example 1)

The substrate wettability promoting composition was produced using the HEC obtained in the above step (C).

More specifically, a HEC powder (weight average molecular weight: 250,000 (polyethylene oxide), product name: SE-400, manufactured by Daicel Precision Chemical Co., Ltd.) of a commercial product is used first, so that the concentration of HEC becomes 1 Water is added thereto in a mass % manner, and a cellulose derivative solution is produced by stirring.

Next, the obtained cellulose derivative solution is filled with a strong acid cation. A column of an ion exchange resin (exchange group: sulfonic acid group, product name: UBK-116, manufactured by Mitsubishi Chemical Corporation) was used to remove cations contained in impurities derived from the production of the cellulose derivative.

The obtained cellulose derivative solution was adjusted so that the concentration of HEC became 1% by mass, and a composition for promoting wettability of the substrate was produced.

(Example 2)

The HEC production-promoting substrate wettability composition obtained in the above steps (B) and (C) was sequentially used.

First, proceed to step (B).

Specifically, a commercially available HEC powder (product weight average molecular weight 250,000 (polyethylene oxide equivalent)) was used using a vibrating screen machine (product name: electromagnetic sieve vibrating machine, AS controller, manufactured by Retsch Co., Ltd.). , product name: SE-400, classified by Daicel Precision Chemical Co., Ltd.). At this time, the recovery is passed through a stainless steel test sieve according to JIS ( 200mm × H45mm, opening degree 100μm).

Then proceed to step (C).

Specifically, the step (C) was carried out in the same manner as in Example 1 except that the HEC powder of the commercial product was changed to the HEC powder classified in the step (B).

The cellulose derivative solution obtained in the step (C) was adjusted so that the concentration of the HEC became 1% by mass to produce a substrate-wetting composition.

(Example 3)

The HEC production-promoting substrate wettability composition obtained in the above steps (A) and (C) was sequentially used.

First, proceed to step (A).

Specifically, a commercially available HEC powder (weight average molecular weight: 250,000 (polyethylene oxide), product name: SE-400, manufactured by Daicel Precision Chemical Co., Ltd.) was used to make the concentration of HEC 1 mass. In the manner of %, water was added thereto, and a cellulose derivative solution was produced by stirring.

Next, the obtained cellulose derivative solution was filtered with a polypropylene filter (opening degree: 1 μm, product name: Profile II, manufactured by Nippon Pall Co., Ltd.).

Then proceed to step (C).

Specifically, in the same manner as in Example 1, except that the cellulose derivative solution obtained by dissolving the commercially available HEC powder in water was changed to the filtrate obtained in the step (A), the step (C) was carried out in the same manner as in Example 1. .

The cellulose derivative solution (derived from the filtrate) obtained in the step (C) was adjusted so that the concentration of the HEC became 1% by mass to produce a substrate-wetting composition.

(Example 4)

The substrate-wettable composition was produced by sequentially performing the HEC obtained in the above steps (B), (A), and (C).

First, proceed to step (B).

Specifically, the classified method was obtained in the same manner as in Example 2. HEC powder.

Next, the step (A) is carried out.

Specifically, the step (A) was carried out in the same manner as in Example 3 except that the HEC powder of the commercial product was changed to the HEC powder classified in the step (B).

Finally, proceed to step (C).

Specifically, in the same manner as in Example 1, except that the cellulose derivative solution obtained by dissolving the commercially available HEC powder in water was changed to the filtrate obtained in the step (A) of the present Example, Carry out step (C).

The cellulose derivative solution (derived from the filtrate) obtained in the step (C) was adjusted so that the concentration of the HEC became 1% by mass to produce a substrate-wetting composition.

(Comparative Example 2)

The substrate wettability promoting composition was produced using the HEC obtained in the above step (B).

More specifically, a substrate-inducing wettable composition was produced in the same manner as in Example 2 except that the step (C) was not carried out.

(Comparative Example 3)

The substrate wettability promoting composition was produced using the HEC obtained by the above step (A).

In more detail, except that step (C) is not carried out, In the same manner as in Example 3, a substrate-inducing wettable composition was produced.

(Comparative Example 4)

The substrate-wettable composition was produced by sequentially performing the HEC obtained in the above steps (B) and (A).

More specifically, a substrate-improving substrate wettability composition was produced in the same manner as in Example 4 except that the step (C) was not carried out.

[Performance Evaluation]

The substrate wettability-promoting materials produced in the above Examples 1 to 4 and Comparative Examples 1 to 4 were used to evaluate various properties.

(Measurement of strong heat residue)

The strong thermal residue of the substrate wettability promoting composition was determined.

Specifically, the empty weight of the magnetic crucible is first measured.

Next, the substrate wettability-promoting composition was placed in a constant temperature drier at 105 ° C for 24 hours to obtain a dried product of the composition (hereinafter referred to as "measurement sample").

Subsequently, about 1 g of the measurement sample was placed in a magnetic crucible, and the weight of the magnetic crucible was measured, and the weight (S (g)) of the measurement sample was determined from the difference from the empty weight of the magnetic crucible.

Next, 3 mL of sulfuric acid was placed in a magnetic mortar and stirred with a glass rod. Next, the magnetic crucible was heated using an electric heater, and the heating was terminated when the measurement sample no longer produced white smoke. Subsequently, the magnetic crucible was placed at 600 ° C in an electric furnace. Heat for 180 minutes.

After air cooling, the weight of the magnetic crucible was measured, and the weight of the ash (W (g)) was determined from the difference between the empty weight of the magnetic crucible, and the strong heat residue (% by weight) was calculated by the following formula (1). .

[Number 1] Strong heat residue (% by weight) = 100 × W / S (1)

In the above formula (1), S is a measured sample weight (g), and W is an ash weight (g).

Further, the ash contains ash derived from impurities such as poorly soluble inorganic salts, aggregates, and unreacted cellulose.

(Measurement of magnesium content and calcium content)

The magnesium content and the calcium content in the substrate wettability composition (hydrophilic component: 1% by mass) were determined.

Specifically, the substrate-wettable composition was produced using ICPS-8100 (manufactured by Shimadzu Corporation) as a measuring device, and inductively coupled high-frequency plasma spectrometry (ICP-AES) was used to determine the wettability of the substrate. Magnesium content and calcium content in the composition. At this time, the average value of n=3 is obtained, and the decimal point is rounded off.

(Measurement of LPC)

Determination of LPC (large particle number) in the substrate wettability composition (Large Particle Count)). Here, the number of coarse particles of 0.7 μm or more which are present in the substrate wettability composition is measured.

Specifically, LPC was measured using Accusizer (registered trademark) FX (manufactured by Particle Sizing Systems, USA) as a measuring device. At this time, the average value of n=3 is obtained, and the decimal point is rounded off.

The performance evaluation results of Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1 below.

From the results of Comparative Example 1 of Table 1, the amount of the strong heat residue, the amount of calcium, and the amount of magnesium in the substrate wettability composition were increased for the HEC powder used this time. Further, the number of LPCs of 0.7 μm or more in the substrate wettability composition is also increased.

Therefore, the substrate-wettable composition of Comparative Example 1 was not obtained. The possibility of excellent wettability. Further, when the substrate-wettable composition of Comparative Example 1 is used for polishing a substrate such as a tantalum wafer, since the substrate wettability-promoting composition contains impurities, it is understood that defects such as LPD may occur on the polished substrate. possibility.

Further, when comparing Comparative Example 1 and Examples 1 to 4, it is understood that the amount of the strong heat residue, the amount of calcium, and the amount of magnesium are reduced by the step of removing or reducing impurities in the cellulose derivative, so the above impurities Most are derived from the manufacturer of cellulose derivatives.

From the comparison of Examples 1 to 4 of Table 1 with Comparative Examples 2 to 4, it can be understood that most of the steps of removing the cations contained in the impurities derived from the production of the cellulose derivative by the step (C) are removed. Impurities. Therefore, it is understood that the HEC powder used this time is a large part of impurities which are poorly soluble inorganic salts.

In addition, from the comparison of the results of Examples 1 and 2 of Table 1 with the results of Examples 3 and 4, it can be understood that by including the step (A), that is, the step of dissolving and filtering the cellulose derivative, the LPC can be intentionally reduced. number. Therefore, the use of the substrate-wettable composition which utilizes the cellulose derivative of the step (A) is used, and for example, when the substrate is polished, there is a possibility that LPD due to coarse particles can be prevented. Further, from the comparison of the results of Examples 2 and 4 of Table 1, it is understood that by including the step (A), the strong heat residue, the calcium content, the magnesium content, and the LPC are all reduced.

Furthermore, from the comparison of the results of Examples 3 and 4 of Table 1, it can be understood that by including the step (B), the step of classifying the cellulose derivative, the strong heat residue, the calcium content, the magnesium content and the LPC all. Both are reduced.

Further, the present application is based on Japanese Patent Application No. 2012-274893, filed on Dec. 17, 2012, and Japanese Patent Application No. 2012-283170, filed on Dec. Quoted.

Claims (6)

A substrate-wetting composition comprising a hydrophilic component containing a cellulose derivative as a main component and a solvent component, and impurities derived from the production of the cellulose derivative are 0.1% by mass or less. The substrate-wettable composition according to claim 1, wherein the impurity contains at least one of magnesium and calcium, and the content of at least one of the magnesium and the calcium is 15 ppb or less based on the total amount of the substrate-wettable composition. A polishing composition comprising the substrate-improving substrate wettable composition according to claim 1 or 2, cerium oxide particles, and a basic compound. A polishing composition comprising a hydrophilic component containing a cellulose derivative as a main component, cerium oxide particles, a basic compound, and a solvent component, and the impurities are 0.1% by mass or less. The polishing composition according to claim 4, wherein the impurities include at least one of magnesium and calcium, and the content of at least one of the magnesium and the calcium is 10 ppb or less based on the total amount of the polishing composition. A method of producing a substrate, comprising: polishing a substrate with the polishing composition according to any one of claims 3 to 5.