JP2017179333A - Composition for polishing used for polishing of polishing object having metal-containing layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for polishing, in the polishing for tungsten, capable of sufficiently attaining flatness or capable of securing a low etching rate and a high polishing rate in a well balance.SOLUTION: Provided is a composition for polishing used for the polishing of a polishing object having a metal-containing layer, comprising abrasives, an oxidizer, a dispersion medium and an anticorrosive including an acidic functional group and a basic functional group. The acid value of the anticorrosive is 5 to 150 mgKOH/g and its amine value is 5 to 150 mgKOH/g. The compound represented by formula (1) is preferable(R1 and R2 denote H or a substituted or nonsubstituted 8 to 16C alkyl group; Y1 and Y2 denote a single bond or -(R3O)n-*; R3 respectively independently denotes a 2 to 6 polyoxyalkylene group; n denotes the integer of 2 to 200; * denotes a position combined to R1 or R2; and X+ denotes an ammonium ion or the primary to quarternary ammonium ion).SELECTED DRAWING: None

Description

  The present invention relates to a polishing composition used for polishing a polishing object having a layer containing a metal.

  In recent years, electronic devices such as computers have achieved high performance such as downsizing, multi-functionality, and high speed due to high integration brought about by miniaturization of LSI manufacturing processes. A chemical mechanical polishing (CMP) method is used in a new microfabrication technology accompanying such high integration of LSI. The CMP method is a technique frequently used in planarization of an interlayer insulating film, formation of a metal plug, and formation of a buried wiring (damascene wiring) in an LSI manufacturing process, particularly in a multilayer wiring forming process.

  In general, a metal plug or a wiring in a semiconductor device is formed by forming a conductor layer made of a metal as described above on an insulator layer made of silicon oxide having a recess and then forming a conductor layer on the insulator layer. This is done by removing a portion by polishing until the insulator layer is exposed. This polishing process is roughly divided into a main polishing process for performing polishing for removing most of the conductor layer to be removed, and a buff polishing process for final polishing of the conductor layer and the insulator layer.

  A general method of CMP is to apply a polishing pad on a circular polishing platen (platen), immerse the surface of the polishing pad with a polishing composition, and press the surface on which the metal film of the substrate is formed. A polishing platen is rotated with a predetermined pressure (polishing pressure) applied, and the metal film (for example, tungsten) is removed by mechanical friction between the polishing composition and the metal film. Further, the action of chemical components contained in the polishing composition increases the mechanical polishing effect due to the relative movement of the polishing composition and the object to be polished, and a high-speed and smooth polishing surface can be obtained.

  A polishing composition used in a semiconductor device manufacturing process generally includes a polishing accelerator such as an acid, an oxidizing agent, and abrasive grains. In contrast, in Patent Document 1, a peroxy oxidant-free CMP polishing slurry composition has been reported on the assumption that the use of a peroxy oxidant causes a recess in the tungsten plug (a phenomenon in which tungsten is excessively polished). ing.

JP2013-42131A

However, when the polishing composition of Patent Document 1 is used in a process for forming a tungsten plug or a tungsten wiring, particularly in a buff polishing step in the same process, it has been confirmed that the polished surface of tungsten is roughened.

  In the composition of Patent Document 1, the surface after polishing becomes rough, and sufficient flattening cannot be achieved.

  Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a polishing composition used for polishing a polishing object having a metal-containing layer that can achieve sufficient planarization.

  Another object of the present invention is to provide a polishing composition used for polishing an object to be polished having a metal-containing layer that can ensure a low etching rate and a high polishing rate in a balanced manner.

  In order to solve the above-mentioned problems, the present inventors have intensively studied. As a result, the inventors found that the above problems can be solved by using an anticorrosive agent having an acidic functional group and a basic functional group in the composition, and completed the present invention.

  That is, the above objects are polishing compositions used for polishing an object to be polished having a metal-containing layer, and include abrasive grains, an oxidizing agent, a dispersion medium, an acidic functional group, and a basic functional group. It can achieve by the polishing composition containing the anticorrosive which has.

  By using the polishing composition of the present invention, a polishing object having a metal-containing layer can be polished smoothly. In addition, by using the polishing composition of the present invention, a polishing object having a metal-containing layer can be polished at a high polishing rate while keeping the etching rate low.

  A polishing composition used for polishing an object to be polished having a metal-containing layer according to the present invention includes abrasive grains, an oxidizing agent, a dispersion medium, and an anticorrosive having an acidic functional group and a basic functional group. Polishing composition. According to the polishing composition having the above configuration, a polishing object having a metal-containing layer can be polished smoothly. In addition, according to the polishing composition of the present invention, a polishing object having a metal-containing layer that is a polishing object can be polished at a high polishing rate while keeping the etching rate low.

  In the present specification, “a polishing composition used for polishing a polishing object having a metal-containing layer” is also simply referred to as “a polishing composition according to the present invention” or “a polishing composition”. The “polishing object having a metal-containing layer” is also simply referred to as “metal polishing object”.

The composition of Patent Document 1 includes a diquaternary compound of formula (I) (particularly a quaternary amine compound; paragraph “0029”) composed of a divalent cation moiety and a divalent anion moiety. The presence of this diquaternary compound can surely keep the etching rate low. However, since the cation portion of the diquaternary compound is adsorbed on the surface of the abrasive grains (for example, Si ⁻ ) and induces aggregation and settling of the abrasive grains, the stability of the abrasive grains decreases. At the same time, since the secondary particle diameter of the abrasive grains becomes large, the surface after polishing becomes rough (the value of the surface roughness RMS is high). Since the start of the CMP process, tungsten has been applied because of its high electrical conductivity and high embeddability. However, it is widely known that tungsten is difficult to process due to its high hardness and brittleness, and the final finished surface roughness is poor compared to metals such as copper and aluminum. In addition to the above, surface roughness of tungsten crystal grains has become an important issue due to recent miniaturization (high integration). This surface roughness is also referred to as chemical mechanical polishing (hereinafter simply referred to as “CMP”). It is required to be resolved with For this reason, with the composition of the said patent document 1, the planarization currently requested | required cannot fully be achieved. In the composition of Patent Document 1, potassium iodate is essentially used as an oxidizing agent, and this oxidizing agent promotes the formation of a metal oxide film (for example, a tungsten oxide (WO ₃ ) film). However, this potassium iodate causes iodine gas to be generated. Iodine gas induces coughing, wheezing, breathing difficulty, etc. when inhaled by humans.Therefore, when manufacturing a composition or polishing work using the composition, ventilation should be sufficient, and workers should wear protective gloves and protective clothing. It is necessary to strictly manage the work environment, such as the need to wear an iron, and in view of the health of the work environment in recent years, it is desirable not to use compounds containing iodine as much as possible.

In contrast, the present invention is characterized by using an anticorrosive agent having an acidic functional group and a basic functional group in the composition. According to this configuration, an object to be polished having a metal-containing layer can be polished smoothly (low surface roughness (RMS)) without using the diquaternary compound. In addition, by using the polishing composition of the present invention, a polishing object having a metal-containing layer can be polished at a high polishing rate while keeping the etching rate low. Although the detailed mechanism which has the said effect is unknown, it thinks as follows. The following mechanism is speculative and does not limit the technical scope of the present invention. That is, as described above, conventionally, since metal films including tungsten are difficult to be etched, emphasis has been placed on polishing an object to be polished having a metal-containing layer at a high polishing rate. However, in recent years, technology that can reduce the thickness of metal-containing layers (polishing objects having metal-containing layers) has been developed, so improvement in the polishing rate is not so important. As a result, the emphasis has been placed on the flattening of the surface. In general, chemical mechanical polishing (CMP) of a metal-containing layer is performed by the following mechanism: The surface of the metal-containing layer is oxidized by the oxidizing agent contained in the polishing composition, and the metal is deposited on the substrate surface. An oxide film is formed. The metal oxide film is polished by being physically scraped by abrasive grains, and the polished metal surface is also oxidized by an oxidizing agent to form a metal oxide film, and the metal oxide film is scraped by abrasive grains. Repeat the cycle. However, the conventional method has a problem that the substrate surface after polishing does not have sufficient smoothness. The inventors of the present invention have made extensive studies on the above problems, and have estimated that the corrosion of the grain boundary between crystal grains is the cause of the decrease in the surface roughness. That is, when a metal oxide (for example, tungsten oxide) comes into contact with water and dissolves as a metal hydroxide (for example, tungsten hydroxide), dissolution by this chemical reaction is faster than scraping with abrasive grains. It was estimated that the etching rate increased and surface roughness occurred. Here, increasing the scraping speed with abrasive grains has been studied as one of the means for solving the problem, but it is necessary to increase the abrasive grain concentration, and the practicality is low due to high cost. For this reason, the present inventors have intensively studied other means for suppressing the dissolution, that is, the etching rate, and use an anticorrosive having an acidic functional group and a basic functional group in the polishing composition. Was considered effective. Specifically, the anticorrosive having an acidic functional group (anionic functional group) and a basic functional group (cationic functional group) is adsorbed on the surface of a metal oxide (eg, tungsten oxide) and covers the metal oxide. An etching-inhibiting film is formed on the surface to suppress dissolution of the metal oxide. When a polishing composition containing such an anticorrosive agent is used, dissolution (elution) of a metal (for example, tungsten) from a substrate can be suppressed during polishing, and the surface roughness after polishing can be reduced. Moreover, when using the cationic anticorrosive of the diquaternary compound like patent document 1, since the zeta potential of the abrasive grain (for example, Si ⁻ ) surface is negatively charged, the anticorrosive is abrasive. When a large amount of an anticorrosive agent is used to obtain a good anticorrosive effect, it causes agglomeration and further sedimentation of the abrasive grains. If the amount of the anticorrosive used is reduced in order to avoid agglomeration of the abrasive grains, it becomes impossible to obtain a good etching rate suppressing effect. However, the anticorrosive agent according to the present invention has a cationic basic functional group and an anionic acidic functional group, and the cationic functional group is adsorbed to the metal oxide, and at the same time, the anionic functional group is also self-organized. Therefore, a relatively small amount of anticorrosive agent can be used to form a film on the surface of the metal oxide without causing agglomeration of the abrasive grains, and the etching rate can be suppressed. .

  Therefore, according to the polishing composition of the present invention, a metal-containing layer (polishing object) can be polished at a high polishing rate while keeping the etching rate low. In addition, since metal elution can be suppressed, when a metal-containing layer (polishing object) is polished with the polishing composition of the present invention, the surface roughness (RMS) can be reduced and the layer has a flat surface (substrate). Can be obtained. In addition, according to the polishing composition of the present invention, a metal-containing layer (polishing object) can be polished to a smooth surface at a high polishing rate while keeping the etching rate low without increasing the abrasive concentration.

  Embodiments of the present invention will be described below. In addition, this invention is not limited only to the following embodiment.

  In the present specification, unless otherwise specified, measurement of operation and physical properties is performed under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50% RH.

[Polishing object]
The polishing object according to the present invention is a layer containing a metal. Here, the layer containing a metal should just be a thing in which the surface used as grinding | polishing object contains a metal at least. For this reason, the metal-containing layer is a substrate made of metal, a layer containing a metal, or a substrate having a layer made of metal (eg, from a layer containing metal or a metal on a polymer or other metal substrate). It may be a substrate on which a layer to be formed is disposed. Preferably, the layer containing a metal is a layer made of metal (for example, a substrate) or an object to be polished (for example, a substrate) having a layer made of a metal.

  Here, the metal is not particularly limited. For example, tungsten, copper, aluminum, cobalt, hafnium, nickel, titanium, tantalum, gold, silver, platinum, palladium, rhodium, ruthenium, iridium, osmium, and the like can be given. The metal may be contained in the form of an alloy or a metal compound. These metals may be used alone or in combination of two or more. The polishing composition of the present invention can be suitably used for a high integration technique brought about by miniaturization of an LSI manufacturing process, and is particularly suitable for polishing a material for plugs and via holes around a transistor. Moreover, as a material to fill, tungsten, copper, aluminum, and cobalt are preferable, and tungsten is more preferable. That is, according to a preferred embodiment of the present invention, the metal is tungsten (the polishing composition of the present invention is used for polishing an object to be polished having a layer containing tungsten).

[Polishing composition]
The polishing composition of the present invention comprises abrasive grains, an oxidizing agent, a dispersion medium, and an anticorrosive agent having an acidic functional group and a basic functional group. Hereinafter, the structure of the polishing composition of this invention is demonstrated.

(Abrasive grains)
The polishing composition of the present invention essentially contains abrasive grains. The abrasive grains contained in the polishing composition have an action of mechanically polishing the object to be polished, and improve the polishing rate of the object to be polished by the polishing composition.

  The abrasive used may be any of inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of the inorganic particles include particles made of metal oxides such as silica, alumina, ceria, titania, silicon nitride particles, silicon carbide particles, and boron nitride particles. Specific examples of the organic particles include polymethyl methacrylate (PMMA) particles. These abrasive grains may be used alone or in combination of two or more. The abrasive grains may be commercially available products or synthetic products.

  Among these abrasive grains, silica is preferable, and colloidal silica is particularly preferable.

  The abrasive grains may be surface-modified. Since ordinary colloidal silica has a zeta potential value close to zero under acidic conditions, silica particles are not electrically repelled with each other under acidic conditions and are likely to agglomerate. In contrast, abrasive grains whose surfaces are modified so that the zeta potential has a relatively large negative value even under acidic conditions are strongly repelled from each other and dispersed well even under acidic conditions. As a result, the storage stability of the polishing composition can be improved. Such surface-modified abrasive grains can be obtained, for example, by mixing a metal such as aluminum, titanium or zirconium or an oxide thereof with the abrasive grains and doping the surface of the abrasive grains.

  Of these, colloidal silica having an organic acid immobilized thereon is particularly preferable. The organic acid is immobilized on the surface of the colloidal silica contained in the polishing composition, for example, by chemically bonding a functional group of the organic acid to the surface of the colloidal silica. If the colloidal silica and the organic acid are simply allowed to coexist, the organic acid is not fixed to the colloidal silica. For immobilizing sulfonic acid, which is a kind of organic acid, on colloidal silica, see, for example, “Sulphonic acid-functionalized silica through quantitative oxides of thiol groups”, Chem. Commun. 246-247 (2003). Specifically, a silane coupling agent having a thiol group such as 3-mercaptopropyltrimethoxysilane is coupled to colloidal silica, and then the sulfonic acid is immobilized on the surface by oxidizing the thiol group with hydrogen peroxide. The colloidal silica thus obtained can be obtained. Alternatively, if the carboxylic acid is immobilized on colloidal silica, for example, “Novel Silene Coupling Agents Containing a Photolabile 2-Nitrobenzoyl Ether for the Introducing the Carboxy Group” 229 (2000). Specifically, colloidal silica having a carboxylic acid immobilized on the surface can be obtained by irradiating light after coupling a silane coupling agent containing a photoreactive 2-nitrobenzyl ester to colloidal silica. .

  The average degree of association of the abrasive grains is also preferably less than 5.0, more preferably 3.0 or less, and even more preferably 2.5 or less. As the average degree of association of the abrasive grains becomes smaller, the surface roughness due to the shape of the abrasive grains can be improved within such a range. The average degree of association of the abrasive grains is also preferably 1.0 or more, and more preferably 1.05 or more. This average degree of association is obtained by dividing the value of the average secondary particle diameter of the abrasive grains by the value of the average primary particle diameter. As the average degree of association of the abrasive grains increases, there is an advantageous effect that the polishing rate of the object to be polished by the polishing composition is improved.

  The lower limit of the average primary particle diameter of the abrasive grains is preferably 10 nm or more, more preferably 15 nm or more, and further preferably 20 nm or more. Further, the upper limit of the average primary particle diameter of the abrasive grains is preferably 200 nm or less, more preferably 150 nm or less, and further preferably 100 nm or less. Within such a range, the polishing rate of the object to be polished by the polishing composition is improved, and the occurrence of surface defects on the surface of the object to be polished after polishing with the polishing composition is further suppressed. be able to. In addition, the average primary particle diameter of an abrasive grain is calculated based on the specific surface area of the abrasive grain measured by BET method, for example.

  The lower limit of the average secondary particle diameter of the abrasive grains is preferably 15 nm or more, more preferably 20 nm or more, and further preferably 30 nm or more. Further, the upper limit of the average secondary particle diameter of the abrasive grains is preferably 300 nm or less, more preferably 260 nm or less, and further preferably 220 nm or less. Within such a range, the polishing rate of the object to be polished by the polishing composition is improved, and the occurrence of surface defects on the surface of the object to be polished after polishing with the polishing composition is further suppressed. be able to. The secondary particles referred to here are particles formed by association of abrasive grains in the polishing composition, and the average secondary particle diameter of the secondary particles is measured by, for example, a dynamic light scattering method. be able to.

  The upper limit of the aspect ratio of the abrasive grains in the polishing composition is less than 2.0, preferably 1.8 or less, and more preferably 1.5 or less. Within such a range, the surface roughness caused by the shape of the abrasive grains can be made favorable. The aspect ratio is a value obtained by taking the smallest rectangle circumscribing the image of the abrasive grains with a scanning electron microscope and dividing the length of the long side of the rectangle by the length of the short side of the same rectangle. And can be obtained using general image analysis software. The lower limit of the aspect ratio of the abrasive grains in the polishing composition is 1.0 or more. The closer to this value, the better the surface roughness due to the shape of the abrasive grains.

  The particle diameter (D90) and the total particle weight of all particles when the cumulative particle weight reaches 90% of the total particle weight from the fine particle side in the particle size distribution obtained by the laser diffraction scattering method in the abrasive grains in the polishing composition The lower limit of D90 / D10, which is the ratio to the particle diameter (D10) when reaching 10%, is 1.1 or more, preferably 1.2 or more, and preferably 1.3 or more. More preferred. Further, the particle diameter (D90) when the accumulated particle weight reaches 90% of the total particle weight from the fine particle side in the particle size distribution obtained by the laser diffraction scattering method in the abrasive grains in the polishing composition, and the total of all the particles The upper limit of the ratio D90 / D10 to the particle diameter (D10) when reaching 10% of the particle weight is not particularly limited, but is preferably 2.04 or less. Within such a range, the surface roughness caused by the shape of the abrasive grains can be made favorable.

  The lower limit of the content of the abrasive grains in the polishing composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and most preferably 1% by mass or more. . Further, the upper limit of the content of the abrasive grains in the polishing composition is preferably 50% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less. Within such a range, the polishing rate of the polishing object can be improved, and the cost of the polishing composition can be reduced, and the surface on the surface of the polishing object after polishing with the polishing composition can be reduced. It is possible to further suppress the occurrence of defects.

(Anticorrosive)
The polishing composition of the present invention essentially contains an anticorrosive agent having an acidic functional group and a basic functional group. Due to the presence of the anticorrosive agent according to the present invention, dissolution (elution) of the metal to be polished is suppressed, and the metal-containing layer (polishing object) can be polished smoothly (with low surface roughness (RMS)). Further, the metal-containing layer (polishing object) can be polished at a high polishing rate while keeping the etching rate low.

  Examples of the acidic functional group of the anticorrosive according to the present invention include a carboxyl group, an acid anhydride group, a sulfo group, a thiol group, a phosphoric acid group, an acidic phosphoric acid ester group, and a phosphonic acid group. From the viewpoint of film formation speed and film strength on the metal surface, it is preferable that the acidic functional group of the anticorrosive is a carboxyl group, a phosphate group, and a salt thereof, and an acidic phosphate group and a salt thereof. The acidic phosphate group is a group in which some phosphorus-bonded hydroxyl groups are alkoxylated. Examples of the alkoxy group include lower alkoxy groups such as a methoxy group, an ethoxy group, and a propoxy group. The number of carbon atoms in the lower alkoxy group is preferably 1-8.

  Examples of the basic functional group of the anticorrosive according to the present invention include an amino group, an imino group, an ammonium base, and a heterocyclic group having a basic nitrogen atom. From the viewpoint of dispersion stability as a composition, the basic functional group of the anticorrosive agent is preferably an amino group or an ammonium base. The amino group may be a substituted or unsubstituted primary amino group, secondary amino group, or tertiary amino group. The ammonium base may be a tertiary ammonium base or a quaternary ammonium base.

  The acid value of the anticorrosive according to the present invention is preferably 5 to 300 mgKOH / g, more preferably 5 to 150 mgKOH / g. The amine value of the anticorrosive according to the present invention is preferably 5 to 300 mgKOH / g, more preferably 5 to 150 mgKOH / g. That is, according to the preferable form of this invention, the acid value of an anticorrosive agent is 5-150 mgKOH / g, and an amine value is 5-150 mgKOH / g. When the acid value and the amine value are within the above ranges, the anticorrosive agent can effectively form an anticorrosive film on the surface of the object to be polished without causing aggregation of abrasive grains.

  In the present specification, the “acid value” represents an acid value per 1 g of the anticorrosive solid content according to the present invention, and can be determined by potentiometric titration according to JIS-K-0070. The “amine value” represents the amine value per 1 g of the solid content of the anticorrosive agent according to the present invention. The value is calculated by the potentiometric titration method using a 0.1N hydrochloric acid aqueous solution, and then converted into the equivalent value of potassium hydroxide. Say.

  Acidic functional groups adsorb on the surface of the metal oxide that is the object to be polished in a self-organized manner, and basic functional groups adsorb on the surface of the metal oxide that is the object to be polished having a negative zeta potential. By doing so, the anticorrosive forms a film on the surface of the metal oxide. By the coating made of the anticorrosive agent, dissolution (elution) of the metal is suppressed, the etching rate is reduced, and the object to be polished can be polished smoothly.

  The anticorrosive agent having an acidic functional group and a basic functional group of the present invention is preferably a polymer anticorrosive agent. When using a polymer anticorrosive, the weight average molecular weight of the anticorrosive is usually 1,000 or more. The weight average molecular weight is preferably 1,000 to 100,000, and more preferably 1,000 to 10,000. If the weight average molecular weight of the anticorrosive is 1,000 or more, the acidic or basic functional group of the anticorrosive adsorbs on the surface of the object to be polished, and effectively forms an anticorrosion film together with the polymer chain portion of the anticorrosive. it can. On the other hand, if the weight average molecular weight of the anticorrosive agent is 100,000 or less, aggregation with abrasive grains is prevented. The weight average molecular weight can be measured by gel permeation chromatography (GPC) using polystyrene as a standard substance. When using a polymeric anticorrosive as the anticorrosive, the binding position of the acidic functional group and the basic functional group to the polymer is not particularly limited and may be a main chain or a side chain. Both main chain and side chain may be used.

  In one embodiment of the present invention, the anticorrosive agent having an acidic functional group and a basic functional group is a compound represented by the following formula (1):

In formula (1), R ¹ and R ² are each independently a hydrogen atom or a substituted or unsubstituted linear or branched alkyl group having 8 to 16 carbon atoms. Specific examples include a substituted or unsubstituted octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, and the like. More specifically, for example, n- Octyl group, n-decyl group, n-undecyl group, lauryl group (n-dodecyl group), n-tridecyl group, n-tetradecyl group, n-pentadecyl group, isotridecyl group, s-tridecyl group, t-tridecyl group Can be mentioned. Among these, from the viewpoint of suppressing the etching rate, a substituted or unsubstituted linear or branched alkyl group having 12 to 15 carbon atoms is preferable. It is more preferably a substituted or unsubstituted linear or branched alkyl group having 13 carbon atoms (n-tridecyl group, isotridecyl group, s-tridecyl group, t-tridecyl group).

Y ¹ and Y ² are each independently a single bond or a group represented by the following formula (i), and at least one of Y ¹ and Y ² is a group represented by the following formula (i);

In formula (i), R ³ is an alkylene group having 2 to 6 carbon atoms. Specific examples include an ethylene group, an n-propylene group, an i-propylene group, an n-butylene group, an i-butylene group, an n-pentylene group, an n-hexylene group, and a plurality of R ³ are the same. Or different. Among these, R ³ is preferably an ethylene group from the viewpoint of more effectively exerting the effects of the present invention.

  n is an integer of 2 to 200, and among them, n is preferably an integer of 4 to 200, and more preferably an integer of 4 to 130, from the viewpoint of suppressing the etching rate.

* Represents a position bonded to R ¹ or R ² in the formula (1).

X ⁺ is an ammonium ion, a primary ammonium ion, a secondary ammonium ion, a tertiary ammonium ion, or a quaternary ammonium ion. Specific examples include ammonium ion, methylammonium ion, dimethylammonium ion, trimethylethylammonium ion, trimethylpropylammonium ion, trimethylhexylammonium ion, tetrapentylammonium ion and the like. Among these, X ⁺ is an ammonium ion (NH ₄ ⁺ ).

  Specifically, the compound used as the anticorrosive agent of the present invention includes alkyl ether ammonium phosphate having a polyoxyethylene structure. More specifically, for example, polyoxyethylene isotridecyl ether ammonium phosphate (addition mole number of ethylene oxide = 130), polyoxyethylene isotridecyl ether ammonium phosphate (addition mole number of ethylene oxide = 70), polyoxyethylene Ammonium dodecyl ether phosphate (added mole number of ethylene oxide = 20), dipolyoxyethylene (C12-15) alkyl ether ammonium phosphate (added mole number of ethylene oxide = 2), polyoxyethylene (C12-15) alkyl ether phosphorus Ammonium acid (added mole number of ethylene oxide = 2), dipolyoxyethylene lauryl ether sodium phosphate (added mole number of ethylene oxide = 10), dipolyoxyethylene (C12-15) alkyl ether Ammonium ruphosphate (addition moles of ethylene oxide = 4), dipolyoxyethylene (C12-15) alkyl ether ammonium phosphate (addition moles of ethylene oxide = 6), dipolyoxyethylene (C12-15) alkyl ether phosphate Ammonium (added mole number of ethylene oxide = 10), polyoxyethylene lauryl ether ammonium phosphate (added mole number of ethylene oxide = 10), polyoxyethylene (C12-15) alkyl ether ammonium phosphate (added mole number of ethylene oxide = 4) ) And the like. In addition, “C12-15” in the above compound names means those having 12 to 15 carbon atoms in the alkyl group and mixtures thereof.

  The anticorrosive agent according to the present invention may be used alone or in combination of two or more.

  As the anticorrosive agent according to the present invention, a synthetic product or a commercially available product may be used.

  When using a polymer anticorrosive as an anticorrosive having an acidic functional group and a basic functional group, a synthetic polymer may be used. Typical examples of synthetic polymers that can be used are vinyl polymerization polymers and condensation polymerization polymers. The acidic functional group and the basic functional group in the vinyl polymerization polymer having an acidic functional group and a basic functional group are derived from monomers at the time of vinyl polymerization, respectively. Examples of vinyl monomers having an acidic functional group include carboxyls such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, crotonic acid, fumaric acid, maleic acid monoalkyl ester, and fumaric acid monoalkyl ester. And group-containing vinyl monomers. Examples of the monomer having a basic function include N, N-dimethylaminoethyl (meth) acrylate, N-methylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, and N, N-dimethylaminopropyl. Examples thereof include aminoalkyl group-containing acrylates and aminoalkyl group-containing methacrylates such as (meth) acrylate, Nt-butylaminoethyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, and N, N-dimethyl. Examples include aminoalkyl group-containing acrylamide and aminoalkyl group-containing methacrylamide such as aminoethyl (meth) acrylamide and N, N-dimethylaminopropyl (meth) acrylamide. The term “(meth) acryl” means “acryl or methacryl”. Block polymerization may be performed after polymerizing the acidic functional group-containing vinyl monomer and the basic functional group-containing vinyl monomer, respectively, or only one of them may be polymerized and then the other graft-polymerized. Good. Polycondensation polymers such as polyurethane, polyester, polyoxyalkylene, polyoxyalkylene / polyester copolymer, polyamide, phenol resin, urea resin, melamine resin, polycarbonate, epoxy resin, alkyd resin, polyalkyleneimine (polyethyleneimine, etc.), Nitrogen-containing polymers such as polyvinyl pyrrolidone, polyallylamine, polyether polyamine (polyoxyethylene polyamine, etc.) are mentioned.

  The lower limit of the content of the anticorrosive agent in the polishing composition is preferably 0.001% by mass or more, more preferably 0.003% by mass or more, and 0.005% by mass or more. Is more preferable. Further, the upper limit of the content of the anticorrosive agent in the polishing composition is preferably 1% by mass or less, more preferably 0.1% by mass or less, and 0.05% by mass or less. Is more preferable. If it is such a range, the grinding | polishing speed | rate of a grinding | polishing target object will improve more, and it can suppress more that a surface defect arises on the surface of the grinding | polishing target object after grind | polishing using a polishing composition.

(Oxidant)
The polishing composition of the present invention essentially contains an oxidizing agent. The oxidizing agent according to the present invention is not particularly limited, but a peroxide is preferable. That is, according to a preferred embodiment of the present invention, the oxidizing agent is a peroxide. Specific examples of such peroxides include, but are not limited to, hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, potassium monopersulfate and oxone. Etc. The oxidizing agents may be used alone or in combination of two or more. That is, according to a preferred embodiment of the present invention, the peroxide is a group consisting of hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, potassium monopersulfate and oxone. It is at least one selected from more. As the oxidizing agent, persulfates (sodium persulfate, potassium persulfate, ammonium persulfate) and hydrogen peroxide are more preferable, and hydrogen peroxide is particularly preferable.

  The lower limit of the content (concentration) of the oxidizing agent in the polishing composition is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and 0.01% by mass or more. More preferably it is. There is an advantage that the polishing rate by the polishing composition is improved as the content of the oxidizing agent is increased. Further, the upper limit of the content (concentration) of the oxidizing agent in the polishing composition is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 1% by mass or less. preferable. As the content of the oxidizing agent decreases, the material cost of the polishing composition can be reduced, and the processing of the polishing composition after polishing, that is, the advantage of reducing the load of waste liquid treatment can be achieved. Have. Further, excessive oxidation of the surface of the object to be polished is less likely to occur, and there is an advantage of reducing the roughness of the metal surface after polishing.

  In addition, since an oxide film is formed on the surface of the layer containing a metal by the oxidizing agent, the oxidizing agent is preferably added immediately before polishing.

(Dispersion medium)
The polishing composition of the present invention contains a dispersion medium in order to disperse or dissolve each component. Here, the dispersion medium is not particularly limited, but water is preferable. From the viewpoint of suppressing the inhibition of the action of other components, water containing as little impurities as possible is more preferable. Specifically, after removing impurity ions with an ion exchange resin, foreign matters are removed through a filter. Pure water, ultrapure water, or distilled water is preferred.

(Other ingredients)
As described above, the polishing composition of the present invention essentially contains abrasive grains, an oxidizing agent, an anticorrosive agent, and a dispersion medium, but may contain other additives in addition to the above components. Here, it does not restrict | limit especially as another additive, The additive normally added to polishing composition can be used. Specific examples include a pH adjuster, a complexing agent, a metal anticorrosive, an antiseptic, an antifungal agent, a reducing agent, a water-soluble polymer, an organic solvent for dissolving a hardly soluble organic substance, and the like. In addition, the polishing composition of this invention does not contain the diquaternary compound described in Unexamined-Japanese-Patent No. 2013-42131 substantially, for example. Further, the polishing composition of the present invention does not substantially contain an iodine compound (for example, potassium iodate) that can trigger generation of iodine gas. Here, “substantially free” means that the target substance is present in a proportion of 10% by mass or less (lower limit: 0% by mass) with respect to the polishing composition. % Or less (lower limit: 0% by mass).

  Hereinafter, among the above-mentioned other additives, a pH adjuster, a complexing agent, a metal anticorrosive, an antiseptic, and an antifungal agent will be described.

(PH adjuster)
The polishing composition of the present invention may further contain a pH adjuster. The pH can be adjusted by adding an appropriate amount of a pH adjusting agent. The pH adjuster used as necessary to adjust the pH of the polishing composition to a desired value may be either acid or alkali, and may be either an inorganic compound or an organic compound. Good. Specific examples of the acid include inorganic acids such as sulfuric acid, nitric 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, glycol Acids, 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 and lactic acid and other carboxylic acids, and methanesulfonic acid, And organic acids such as organic sulfuric acid such as ethanesulfonic acid and isethionic acid. Specific examples of the alkali include ammonia, amines such as ethylenediamine and piperazine, and quaternary ammonium salts such as tetramethylammonium and tetraethylammonium. These pH regulators can be used alone or in combination of two or more.

  The lower limit of the pH of the polishing composition of the present invention is preferably 1.0 or more, more preferably 1.05 or more, and particularly preferably 1.1 or more. As the pH of the polishing composition increases, the handling of the polishing composition becomes easier.

  Moreover, it is preferable that the upper limit of pH of polishing composition is 7 or less, More preferably, it is 5 or less, Most preferably, it is 4.0 or less. As the pH of the polishing composition decreases, the polishing rate of the metal that is the polishing object is improved.

(Complexing agent)
The complexing agent that can be included if necessary in the polishing composition has a function of chemically etching the surface of the polishing object, and more effectively improves the polishing rate of the polishing object by the polishing composition. It can be made.

  Examples of complexing agents that can be used include inorganic acids or salts thereof, organic acids or salts thereof, nitrile compounds, amino acids, and chelating agents. These complexing agents may be used alone or in admixture of two or more. The complexing agent may be a commercially available product or a synthetic product.

  As a complexing agent, the inorganic acid or the salt of the organic acid may be used. In particular, when a salt of a weak acid and a strong base, a salt of a strong acid and a weak base, or a salt of a weak acid and a weak base is used, a pH buffering action can be expected. Examples of such salts include, for example, potassium chloride, sodium sulfate, potassium nitrate, potassium carbonate, potassium tetrafluoroborate, potassium pyrophosphate, potassium oxalate, trisodium citrate, (+)-potassium tartrate, hexafluoro A potassium phosphate etc. are mentioned.

  Specific examples of the nitrile compound include acetonitrile, aminoacetonitrile, propionitrile, butyronitrile, isobutyronitrile, benzonitrile, glutaronitrile, methoxyacetonitrile, and the like.

  Specific examples of amino acids include glycine, α-alanine, β-alanine, N-methylglycine, N, N-dimethylglycine, 2-aminobutyric acid, norvaline, valine, leucine, norleucine, isoleucine, phenylalanine, proline, sarcosine, Ornithine, lysine, taurine, serine, threonine, homoserine, tyrosine, bicine, tricine, 3,5-diiodo-tyrosine, β- (3,4-dihydroxyphenyl) -alanine, thyroxine, 4-hydroxy-proline, cysteine, methionine , Ethionine, lanthionine, cystathionine, cystine, cysteic acid, aspartic acid, glutamic acid, S- (carboxymethyl) -cysteine, 4-aminobutyric acid, asparagine, glutamine, azaserine, arginine, canavanine, cytosine Phosphorus, .delta.-hydroxy - lysine, creatine, histidine, 1-methyl - histidine, 3-methyl - include histidine and tryptophan.

  Specific examples of chelating agents include nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, N, N, N-trimethylenephosphonic acid, ethylenediamine-N, N, N ′, N′-tetramethylenesulfonic acid, transcyclohexane Diamine tetraacetic acid, 1,2-diaminopropanetetraacetic acid, glycol ether diamine tetraacetic acid, ethylenediamine orthohydroxyphenylacetic acid, ethylenediamine disuccinic acid (SS form), N- (2-carboxylateethyl) -L-aspartic acid, β -Alanine diacetate, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, N, N'-bis (2-hydroxybenzyl) ethylenediamine-N, N'-diacetic acid 1,2-dihydroxybenzene-4,6 Such as disulfonic acid and the like.

  Among these, at least one selected from the group consisting of an inorganic acid or a salt thereof, a carboxylic acid or a salt thereof, and a nitrile compound is preferable, from the viewpoint of stability of a complex structure with a metal compound contained in a polishing object. An inorganic acid or a salt thereof is more preferable.

  In the case where the polishing composition contains a complexing agent, the content (concentration) of the complexing agent is not particularly limited. For example, the lower limit of the content (concentration) of the complexing agent is not particularly limited because the effect is exhibited even in a small amount, but is preferably 0.001 g / L or more, and 0.01 g / L or more. More preferably, it is more preferably 1 g / L or more. Further, the upper limit of the content (concentration) of the complexing agent is preferably 20 g / L or less, more preferably 15 g / L or less, and further preferably 10 g / L or less. If it is such a range, the grinding | polishing speed | rate of a grinding | polishing target object will improve, and it is advantageous when improving the smoothness of the surface of a grinding | polishing target object after grind | polishing using a polishing composition.

(Metal anticorrosive)
Next, the metal anticorrosive agent that can be included in the polishing composition if necessary is a metal anticorrosive agent other than the above-mentioned anticorrosive agents having an acidic functional group and a basic functional group. It acts to suppress deterioration of the surface condition such as surface roughness. However, since the anticorrosive agent according to the present invention acts as a metal anticorrosive agent, the polishing composition of the present invention can sufficiently suppress and prevent the dissolution of metal without adding a metal anticorrosive agent separately.

  The metal anticorrosive that can be used is not particularly limited, but is preferably a heterocyclic compound or a surfactant. The number of heterocyclic rings in the heterocyclic compound is not particularly limited. The heterocyclic compound may be a monocyclic compound or a polycyclic compound having a condensed ring. These metal anticorrosives may be used alone or in combination of two or more. In addition, as the metal anticorrosive, a commercially available product or a synthetic product may be used.

  Specific examples of heterocyclic compounds that can be used as metal anticorrosives include, for example, pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, pyridine compounds, pyrazine compounds, pyridazine compounds, pyridine compounds, indolizine compounds, indoles. Compound, isoindole compound, indazole compound, purine compound, quinolidine compound, quinoline compound, isoquinoline compound, naphthyridine compound, phthalazine compound, quinoxaline compound, quinazoline compound, cinnoline compound, buteridine compound, thiazole compound, isothiazole compound, oxazole compound, iso Examples thereof include nitrogen-containing heterocyclic compounds such as oxazole compounds and furazane compounds.

  More specific examples include pyrazole compounds such as 1H-pyrazole, 4-nitro-3-pyrazolecarboxylic acid, 3,5-pyrazolecarboxylic acid, 3-amino-5-phenylpyrazole, 5 -Amino-3-phenylpyrazole, 3,4,5-tribromopyrazole, 3-aminopyrazole, 3,5-dimethylpyrazole, 3,5-dimethyl-1-hydroxymethylpyrazole, 3-methylpyrazole, 1-methyl Pyrazole, 3-amino-5-methylpyrazole, 4-amino-pyrazolo [3,4-d] pyrimidine, allopurinol, 4-chloro-1H-pyrazolo [3,4-D] pyrimidine, 3,4-dihydroxy-6 -Methylpyrazolo (3,4-B) -pyridine, 6-methyl-1H-pyrazolo [3,4-b] pyridine - amine.

  Examples of imidazole compounds include, for example, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1,2-dimethylpyrazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, benzimidazole, 5,6-dimethylbenzimidazole, 2-aminobenzimidazole, 2-chlorobenzimidazole, 2-methylbenzimidazole, 2- (1-hydroxyethyl) benzimidazole, 2-hydroxybenzimidazole, 2-phenylbenzimidazole, 2 , 5-dimethylbenzimidazole, 5-methylbenzimidazole, 5-nitrobenzimidazole and the like.

  Examples of the triazole compound include, for example, 1,2,3-triazole (1H-BTA), 1,2,4-triazole, 1-methyl-1,2,4-triazole, methyl-1H-1,2, 4-triazole-3-carboxylate, 1,2,4-triazole-3-carboxylic acid, methyl 1,2,4-triazole-3-carboxylate, 1H-1,2,4-triazole-3-thiol, 3,5-diamino-1H-1,2,4-triazole, 3-amino-1,2,4-triazole-5-thiol, 3-amino-1H-1,2,4-triazole, 3-amino- 5-benzyl-4H-1,2,4-triazole, 3-amino-5-methyl-4H-1,2,4-triazole, 3-nitro-1,2,4-triazole, 3-bromo-5 Nitro , 2,4-triazole, 4- (1,2,4-triazol-1-yl) phenol, 4-amino-1,2,4-triazole, 4-amino-3,5-dipropyl-4H-1, 2,4-triazole, 4-amino-3,5-dimethyl-4H-1,2,4-triazole, 4-amino-3,5-dipeptyl-4H-1,2,4-triazole, 5-methyl- 1,2,4-triazole-3,4-diamine, 1H-benzotriazole, 1-hydroxybenzotriazole, 1-aminobenzotriazole, 1-carboxybenzotriazole, 5-chloro-1H-benzotriazole, 5-nitro- 1H-benzotriazole, 5-carboxy-1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H Benzotriazole, 1- (1 ′, 2′-dicarboxyethyl) benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, 1- [N, N-bis (hydroxyethyl) amino Methyl] -5-methylbenzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] -4-methylbenzotriazole, and the like.

  Examples of the tetrazole compound include 1H-tetrazole, 5-methyltetrazole, 5-aminotetrazole, and 5-phenyltetrazole.

  Examples of indazole compounds include, for example, 1H-indazole, 5-amino-1H-indazole, 5-nitro-1H-indazole, 5-hydroxy-1H-indazole, 6-amino-1H-indazole, 6-nitro-1H -Indazole, 6-hydroxy-1H-indazole, 3-carboxy-5-methyl-1H-indazole and the like.

  Examples of indole compounds include 1H-indole, 1-methyl-1H-indole, 2-methyl-1H-indole, 3-methyl-1H-indole, 4-methyl-1H-indole, 5-methyl-1H- Indole, 6-methyl-1H-indole, 7-methyl-1H-indole, 4-amino-1H-indole, 5-amino-1H-indole, 6-amino-1H-indole, 7-amino-1H-indole, 4-hydroxy-1H-indole, 5-hydroxy-1H-indole, 6-hydroxy-1H-indole, 7-hydroxy-1H-indole, 4-methoxy-1H-indole, 5-methoxy-1H-indole, 6- Methoxy-1H-indole, 7-methoxy-1H-indole, 4-chloro-1H- Ndole, 5-chloro-1H-indole, 6-chloro-1H-indole, 7-chloro-1H-indole, 4-carboxy-1H-indole, 5-carboxy-1H-indole, 6-carboxy-1H-indole, 7-carboxy-1H-indole, 4-nitro-1H-indole, 5-nitro-1H-indole, 6-nitro-1H-indole, 7-nitro-1H-indole, 4-nitrile-1H-indole, 5- Nitrile-1H-indole, 6-nitrile-1H-indole, 7-nitrile-1H-indole, 2,5-dimethyl-1H-indole, 1,2-dimethyl-1H-indole, 1,3-dimethyl-1H- Indole, 2,3-dimethyl-1H-indole, 5-amino-2,3-dimethyl-1H- Ndole, 7-ethyl-1H-indole, 5- (aminomethyl) indole, 2-methyl-5-amino-1H-indole, 3-hydroxymethyl-1H-indole, 6-isopropyl-1H-indole, 5-chloro -2-methyl-1H-indole and the like.

  Among these, preferred heterocyclic compounds are triazole compounds, and in particular, 1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole, 1- [N, N-bis (hydroxy Ethyl) aminomethyl] -5-methylbenzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] -4-methylbenzotriazole, 1,2,3-triazole, and 1,2,4-triazole Is preferred. Since these heterocyclic compounds have high chemical or physical adsorptive power to the surface of the object to be polished, a stronger protective film can be formed on the surface of the object to be polished. This is advantageous in improving the smoothness of the surface of the object to be polished after polishing with the polishing composition of the present invention.

  Examples of the surfactant used as the metal anticorrosive include an anionic surfactant, a cationic surfactant, and an amphoteric surfactant.

  Examples of anionic surfactants include, for example, polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl sulfuric acid ester, alkyl sulfuric acid ester, polyoxyethylene alkyl ether sulfuric acid, alkyl ether sulfuric acid, alkylbenzene sulfonic acid, alkyl phosphoric acid ester , Polyoxyethylene alkyl phosphate ester, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthalene sulfonic acid, alkyl diphenyl ether disulfonic acid, and salts thereof.

  Examples of the cationic surfactant include alkyl trimethyl ammonium salt, alkyl dimethyl ammonium salt, alkyl benzyl dimethyl ammonium salt, alkyl amine salt and the like.

  Examples of amphoteric surfactants include alkyl betaines and alkyl amine oxides.

  Specific examples of nonionic surfactants include, for example, polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ether, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkyl amines, and alkyl alkanols. Amides are mentioned. Of these, polyoxyalkylene alkyl ether is preferred.

  Among these, preferred surfactants are polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl ether sulfate, alkyl ether sulfate, and alkylbenzene sulfonate. Since these surfactants have a high chemical or physical adsorption force to the surface of the object to be polished, a stronger protective film can be formed on the surface of the object to be polished. This is advantageous in improving the flatness of the surface of the object to be polished after polishing using the polishing composition of the present invention.

  In the case where the polishing composition contains a metal anticorrosive, the content (concentration) of the metal anticorrosive is not particularly limited. For example, the lower limit of the content (concentration) of the metal anticorrosive is preferably 0.001 g / L or more, more preferably 0.005 g / L or more, and 0.01 g / L or more. Further preferred. Further, the upper limit of the content (concentration) of the metal anticorrosive is preferably 10 g / L or less, more preferably 5 g / L or less, and further preferably 2 g / L or less. If it is such a range, melt | dissolution of a metal can be prevented and deterioration of surface conditions, such as surface roughness of a grinding | polishing surface, can be suppressed.

(Preservatives and fungicides)
Furthermore, examples of antiseptics and fungicides that may be included in the polishing composition include 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazoline-3. -Isothiazoline preservatives such as ON, paraoxybenzoates, phenoxyethanol and the like. These antiseptics and fungicides may be used alone or in combination of two or more.

[Method for producing polishing composition]
The production method of the polishing composition of the present invention is not particularly limited, and for example, abrasive grains, an oxidizing agent, an anticorrosive agent, and other additives as necessary are stirred and mixed in a dispersion medium (for example, water). Can be obtained. As described above, the oxidant promotes the formation of an oxide film on the surface of the metal-containing layer. First, abrasive grains, anticorrosives, and other additives as necessary are added to a dispersion medium (for example, water ) To prepare a preliminary composition, and the oxidizing agent is preferably added to the preliminary composition immediately before polishing.

  Although the temperature at the time of mixing each component is not specifically limited, 10-40 degreeC is preferable and you may heat in order to raise a dissolution rate. Further, the mixing time is not particularly limited as long as uniform mixing can be performed.

[Polishing method and substrate manufacturing method]
As described above, the polishing composition of the present invention is suitably used for polishing a metal-containing layer (polishing object). Therefore, this invention also provides the grinding | polishing method which grind | polishes the grinding | polishing target object which has a layer containing a metal with the polishing composition of this invention. Moreover, this invention provides the manufacturing method of a board | substrate including the process of grind | polishing the layer (polishing target object) containing a metal with the said grinding | polishing method.

  As a polishing apparatus, a general holder having a polishing surface plate on which a holder for holding a substrate having a polishing object and a motor capable of changing the number of rotations are attached and a polishing pad (polishing cloth) can be attached. A polishing apparatus can be used.

  As the polishing pad, a general nonwoven fabric, polyurethane, porous fluororesin, or the like can be used without particular limitation. It is preferable that the polishing pad is grooved so that the polishing liquid accumulates.

  As for polishing conditions, for example, the rotational speed of the polishing platen is preferably 10 to 500 rpm. The pressure (polishing pressure) applied to the substrate having the object to be polished is preferably 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 with a pump or the like is employed. Although the supply amount is not limited, it is preferable that the surface of the polishing pad is always covered with the polishing composition of the present invention.

  After the polishing is completed, the substrate is washed in running water, and water droplets adhering to the substrate are removed by a spin dryer or the like, and dried to obtain a substrate having a metal-containing layer.

  The polishing composition of the present invention may be a one-component type or a multi-component type including a two-component type. As described above, the oxidizing agent promotes the formation of an oxide film on the surface of the layer containing a metal. For this reason, a first liquid and an oxidizing agent containing abrasive grains, an anticorrosive agent, a dispersion medium (for example, water), and other additives as required, and a second liquid containing a dispersion medium (for example, water) if necessary. A two-component type consisting of a liquid is preferred. The polishing composition of the present invention may be prepared by diluting the stock solution of the polishing composition, for example, 10 times or more using a diluent such as water.

  The polishing composition of the present invention is preferably used in a metal polishing step, particularly a tungsten polishing step. Further, the polishing composition of the present invention comprises a tungsten polishing step, a main polishing step performed to remove most of the tungsten-containing layer, and a buff polishing step for final polishing the tungsten-containing layer and the insulator layer. It is preferably used in the buffing process when roughly classified into

  The present invention will be described in further detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. Unless otherwise specified, “%” and “part” mean “% by mass” and “part by mass”, respectively. In the following examples, unless otherwise specified, the operation was performed under conditions of room temperature (25 ° C.) / Relative humidity 40 to 50% RH.

<Example>
In 1 L of pure water, the anticorrosive agent shown in Table 1 below is 0.01% by mass with respect to the final polishing composition, abrasive grains (sulfonic acid-fixed colloidal silica; average primary particle size: 30 nm, average secondary particle size) : 60 nm, aspect ratio: 1.24, D90 / D10: 2.01) is added in an amount of 2.0 mass% with respect to the final polishing composition, and the polishing composition has a pH of 2.1. Each polishing composition was prepared by adding a maleic acid aqueous solution (30%). Further, immediately before polishing the tungsten wafer, the above-mentioned polishing solution is stirred while stirring hydrogen peroxide water (30% by mass) as an oxidizing agent so that the final polishing composition is 0.2% by mass. Added to the composition. The pH of the polishing composition (liquid temperature: 25 ° C.) was confirmed with a pH meter (manufactured by Horiba, Ltd., model number: LAQUA).

  About the polishing composition obtained above, according to the following method, polishing rate (Removal Rate) (Å / min), etching rate (Etching Rate) (Å / min), and surface roughness (RMS) were evaluated. The results are shown in Table 1 below.

<Measurement of polishing rate>
Using each polishing composition, the polishing object is polished under the following polishing conditions. The thickness (film thickness) of the object to be polished before and after polishing was measured with a manual sheet resistor (VR-120, manufactured by Hitachi Kokusai Electric Co., Ltd.). The polishing rate (removal rate) (Å / min) was determined by dividing the difference in thickness (film thickness) of the polishing object before and after polishing by the polishing time according to the following (calculation method of polishing rate). A tungsten wafer (size: 32 mm × 32 mm) was used as an object to be polished.

(Polishing conditions)
Polishing machine: Single-side CMP polishing machine (ENGIS)
Polishing pad: Polyurethane pad (IC1010: manufactured by Rohm and Haas)
Pressure: 2.0 psi
Platen (surface plate) rotation speed: 70rpm
Head (carrier) rotation speed: 70 rpm
Flow rate of polishing composition: 150 ml / min
Polishing time: 60 sec
(Calculation method of polishing rate)
The polishing rate (polishing rate) (Å / min) is calculated by the following formula (1).

<Measurement of Etching Rate>
An etching test was performed by the following operation. That is, the polishing object was immersed for 10 minutes in a sample container in which 300 mL of each polishing composition was stirred at 300 rpm. After immersion, the wafer was washed with pure water for 30 seconds and dried by air blow drying with an air gun. The thickness (film thickness) of the object to be polished before and after the etching test is measured with a manual sheet resistor (VR-120, Hitachi Kokusai Electric). The etching rate (Å / min) was determined by dividing the difference in thickness (film thickness) of the object to be polished before and after the etching test by the etching test time according to the following (method for calculating the etching rate). A tungsten wafer (size: 32 mm × 32 mm) was used as an object to be polished.

(Etching rate calculation method)
The etching rate (etching rate) (Å / min) is calculated by the following formula (2).

<Measurement of surface roughness (RMS)>
The object to be polished was polished with the polishing composition in the same manner as in the above [Measurement of polishing rate (Removal Rate)]. The surface roughness (RMS) on the polished surface of the polished object after polishing was measured using a scanning probe microscope (SPM). As SPM, NANO-NAVI2 manufactured by Hitachi High-Technologies Corporation was used. The cantilever was SI-DF40P2. The measurement was performed three times at a scanning frequency of 0.86 Hz, X: 512 pt, and Y: 512 pt, and the average of these values was defined as surface roughness (RMS).

  In the table, POE means polyoxyethylene, and the number after POE means the number of moles of ethylene oxide added. For example, POE (130) isotridecyl ether ammonium phosphate refers to a compound with 130 moles of ethylene oxide added. “C12-15” means an alkyl group having 12 to 15 carbon atoms and mixtures thereof.

  From the results in Table 1 above, a polishing composition containing no anticorrosive agent (Comparative Example 1) or a comparative example using a polishing composition containing an anticorrosive agent having no acidic functional group and basic functional group at the same time ( In Comparative Examples 2 to 8), it can be seen that the etching rate is high and the surface roughness of the polishing object is also at a high level. On the other hand, it turns out that the etching rate of a metal (tungsten) board | substrate was suppressed by using the polishing composition containing the anticorrosive which has an acidic functional group and a basic functional group (Examples 1-11). Further, it is shown that a substrate having a polished surface with a smaller surface roughness (RMS) (ie, excellent smoothness) can be obtained by polishing with the polishing composition of the present invention. Furthermore, it has also been found that the larger the number of moles of ethylene oxide added to the anticorrosive contained in the polishing composition, the higher the polishing rate can be achieved while the etching rate is suppressed.

Claims (7)

A polishing composition used for polishing a polishing object having a layer containing a metal,
A polishing composition comprising abrasive grains, an oxidizing agent, a dispersion medium, and an anticorrosive having an acidic functional group and a basic functional group.   The polishing composition according to claim 1, wherein the metal is tungsten.   The polishing composition according to claim 1 or 2, wherein the anticorrosive has an acid value of 5 to 150 mgKOH / g and an amine value of 5 to 150 mgKOH / g. The anticorrosive agent has the following formula (1):
In Formula (1), R ¹ and R ² are each independently a hydrogen atom or a substituted or unsubstituted linear or branched alkyl group having 8 to 16 carbon atoms,
Y ¹ and Y ² are each independently a single bond or a group represented by the following formula (i), and at least one of Y ¹ and Y ² is a group represented by the following formula (i);
In formula (i), R ³ is an alkylene group having 2 to 6 carbon atoms, a plurality of R ³ may be the same or different, n is an integer of 2 to 200, and * is Represents a position bonded to R ¹ or R ² in formula (1),
X ⁺ is an ammonium ion, a primary ammonium ion, a secondary ammonium ion, a tertiary ammonium ion, or a quaternary ammonium ion;
Polishing composition of any one of Claims 1-3 which is a compound represented by these.   The polishing composition according to claim 1, wherein the oxidizing agent is a peroxide.   The peroxide is at least one selected from the group consisting of hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, potassium monopersulfate and oxone. The polishing composition according to claim 5. The polishing composition according to claim 1, further comprising a pH adjuster.