TWI729095B - Polishing composition for polishing a polishing object having a metal-containing layer - Google Patents

Abstract

The subject of the present invention is to provide a polishing composition for polishing an object to be polished having a metal-containing layer that can achieve sufficient planarization.

The solution of the present invention is a polishing composition, which is used for polishing a polishing object having a metal-containing layer, and is characterized by containing abrasive grains, an oxidizing agent, and a dispersing medium, and having an acidic property. Anti-corrosion agent for functional groups and basic functional groups.

Description

Polishing composition for polishing a polishing object having a metal-containing layer

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

In recent years, due to the high integration brought about by the miniaturization of LSI manufacturing process, the electronic equipment that started with the computer has achieved high performance such as miniaturization, versatility, and high speed. In such a new microfabrication technology that accompanies the high integration of LSI, the chemical mechanical polishing (CMP) method is used. The CMP method is a technology that is frequently used in the LSI manufacturing process, especially the planarization of the interlayer insulating film in the multilayer wiring formation step, the formation of metal plugs, and the formation of embedded wiring (damascene wiring).

In the formation of metal plugs or wiring of semiconductor devices, generally speaking, a conductive layer made of the above-mentioned metal is formed on an insulator layer made of silicon oxide that forms recesses, and then polished to A part of the conductor layer on the insulator layer exposes the insulator layer and is removed. This grinding step is roughly divided into the main grinding step of grinding to remove most of the conductor layer that should be removed, and the polishing and grinding of the conductor layer and insulation. The buffing and grinding step of the rim body layer.

The general method of CMP is to attach a polishing pad on a circular polishing platform (press plate), impregnate the surface of the polishing pad with a polishing composition, press the surface of the metal film of the substrate, and apply a predetermined pressure from the back surface (grinding The polishing platform is rotated under pressure), and the metal film (for example, tungsten) is removed by mechanical friction between the polishing composition and the metal film. In addition, the chemical components contained in the polishing composition increase the mechanical polishing effect by the relative movement of the polishing composition and the object to be polished, thereby obtaining a high-speed and smooth polishing surface.

The polishing composition used in the semiconductor device manufacturing process is generally a polishing accelerator containing an acid or the like, an oxidizing agent, and abrasive grains. Regarding this, in Japanese Patent Laid-Open No. 2013-42131, the use as a peroxy oxidant causes recesses in the tungsten plug (phenomenon caused by excessive grinding of tungsten), and it is reported that there is no peroxy oxidant for CMP polishing slurry composition.

However, in the process of forming tungsten plugs or tungsten wiring, especially when the polishing and polishing step of the same process uses the polishing composition of JP 2013-42131, it is confirmed that the polished surface of tungsten is rough. That is, the composition in the above-mentioned Japanese Patent Application Publication No. 2013-42131 has a problem that the surface after polishing becomes rough, and sufficient planarization cannot be achieved.

Accordingly, the present invention was made in view of the above-mentioned matters, and aims to provide a polishing composition for polishing an object to be polished having a metal-containing layer that can achieve sufficient planarization.

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

The inventors of the present invention have made diligent studies to solve the above-mentioned problems. As a result, it was found that the above-mentioned problems can be solved by using an anticorrosive agent having an acidic functional group and a basic functional group in the composition, and the present invention has been completed.

That is, the above-mentioned objectives can be achieved by the following means.

1. A polishing composition, which is a polishing composition used for polishing a polishing object having a metal-containing layer, characterized by containing abrasive grains, an oxidizing agent, and a dispersing medium, and an acidic functional group and an alkali Anti-corrosion agent for functional groups.

2. The polishing composition according to 1, wherein the aforementioned metal is tungsten.

3. The polishing composition of 1 or 2, wherein the acid value of the anticorrosive agent is 5 to 150 mgKOH/g, and the amine value is 5 to 150 mgKOH/g.

4. The polishing composition according to any one of 1 to 3, wherein the anticorrosive agent 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 with 8 to 16 carbon atoms, and 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 with 2-6 carbon atoms, and the plural R ³ may be the same or different respectively, n is an integer of 2 to 200, and * means the same as R ^{1 in formula (1)} Or where R ^{2 is} bonded, X ⁺ is an ammonium ion, a first-order ammonium ion, a second-order ammonium ion, a third-order ammonium ion, or a fourth-order ammonium ion.

5. The polishing composition according to any one of 1 to 4, wherein the oxidizing agent is peroxide.

6. The polishing composition according to 5, wherein the aforementioned peroxide is selected from hydrogen peroxide, peracetic acid, percarbonate, carbamide peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, and potassium monopersulfate And at least one of the group consisting of potassium peroxymonosulfate (Oxone).

7. The polishing composition according to any one of 1 to 6, wherein the abrasive grains are organic acid-immobilized silica.

8. The polishing composition according to any one of 1 to 7, which further contains a pH adjusting agent.

9. A method of manufacturing a polishing composition, which comprises the steps of mixing abrasive grains, an anticorrosive agent with a dispersion medium to prepare a preliminary composition, and a step of adding an oxidizing agent to the preliminary composition just before polishing.

10. A polishing method for polishing an object to be polished having a metal-containing layer with the polishing composition according to any one of 1 to 8.

11. A method of manufacturing a substrate, which includes polishing such as 10 Method of grinding steps.

The polishing composition of the present invention for polishing an object to be polished having a metal-containing layer includes abrasive grains, an oxidizing agent, a dispersion medium, and an anticorrosive agent having acidic functional groups and basic functional groups. Things. In the case of the polishing composition having the above-mentioned structure, it is possible to smoothly polish an object to be polished having a layer containing a metal. Furthermore, according to the polishing composition of the present invention, the polishing target, that is, the polishing target having a metal-containing layer, can be polished at a low etching rate and can be polished at a high polishing rate.

In this specification, the "polishing composition used for polishing of a polishing object having a metal-containing layer" is also simply referred to as the "polishing composition related to the present invention" or the "polishing composition". The "object to be polished having a layer containing metal" is also simply referred to as the "object to be polished metal".

The composition of the above-mentioned Japanese Patent Application Publication No. 2013-42131 includes the second grade 4 compound of formula (I) composed of a divalent cation part and a divalent anion part (for example, the fourth grade described in the paragraph "0029"). Amine compound). With the presence of the aforementioned two fourth-level compounds, the etching rate of tungsten can be suppressed to a low level. However, the two compounds 4 cation portion of sorption because the abrasive grains (e.g. Si ^-) surface, the agglomerated abrasive grain precipitation derived Further, reduced stability of abrasive grains. At the same time, as the secondary particle size of the abrasive grains increases, the surface of the object to be polished after polishing becomes coarser (the value of surface roughness RMS increases). From the early stage of the CMP process, tungsten has been used because of high electrical conductivity or high embedding. However, tungsten is difficult to process due to its high hardness or brittleness. The final roughness of the polished surface is inferior to that of metals such as copper or aluminum. It has been widely known. In addition to the above, the surface roughness of tungsten crystal grains has become an important problem due to the miniaturization (high accumulation) in recent years. It is being sought to use Chemical Mechanical Polishing (Chemical Mechanical Polishing; hereinafter also simply referred to as "CMP"). )eliminate. As a result, the composition of the aforementioned Japanese Patent Application Laid-Open No. 2013-42131 cannot sufficiently achieve the flattening of the object to be polished that is currently required. In addition, in the composition of Japanese Patent Application Laid-Open No. 2013-42131, potassium iodate must be 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, the aforementioned potassium iodate becomes a cause of iodine gas. When iodine gas is inhaled into the human body, it may induce coughing, wheezing, dyspnea, etc., or during the manufacture of the composition or the grinding operation using the composition, adequate ventilation, the operator must wear a protective handbag or protective clothing, etc. It is necessary to strictly manage the working environment, and when evaluating the improvement of the working environment in recent years, it is expected that compounds containing iodine should not be used as much as possible.

In this regard, the present invention is characterized by being used as an anticorrosive agent having acidic functional groups and basic functional groups in the composition. With this configuration, even without using the aforementioned second and fourth-level compounds, it is possible to smoothly polish (at low surface roughness (RMS)) an object to be polished having a metal-containing layer. Furthermore, by using the polishing composition of the present invention, a polishing target having a metal-containing layer can be polished at a high polishing rate while suppressing the etching rate at a low level. Although the detailed mechanism for exerting the above effects is not clear, it is considered as follows. However, the following mechanisms are speculations and do not limit the technical scope of the present invention. That is, as mentioned above, in the past, since it is difficult to etch tungsten as a metal film for the first time, the emphasis has been placed on polishing an object to be polished with a metal-containing layer at a fast polishing rate. However, in recent years, as the technology for thinning the metal-containing layer (the polishing object with the metal-containing layer) has been developed, the improvement of polishing speed is not so important. Instead, the focus of miniaturization accompanying the LSI manufacturing process has been replaced. Flatten on the surface. Generally, the chemical mechanical polishing (CMP) of the 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 to form a metal oxide film on the surface of the substrate. The metal oxide film is polished by physical scraping by abrasive grains, and the polished metal surface is oxidized by an oxidizing agent to form a metal oxide film, and the cycle of scraping the metal oxide film with abrasive grains is repeated. However, in the conventional method, there is a problem that the surface of the substrate after polishing does not have sufficient smoothness. When the present inventors diligently studied the above-mentioned problems, they presumed that the corrosion of the grain boundaries between crystal grains is the cause of the decrease in surface roughness. That is, it can be inferred that although metal oxides (such as tungsten oxide) are brought into contact with water to dissolve metal hydroxides (such as tungsten hydroxide), the rate of dissolution by this chemical reaction is higher than that by abrasive grains. Scrape faster, increase the etching speed, and produce surface roughness. Here, increasing the scraping speed by abrasive grains has also been studied as one of the solutions, but it is necessary to increase the concentration of abrasive grains, which is considered to be low in practicality due to high cost. Therefore, the inventors of the present invention conducted diligent research on the above-mentioned dissolution, that is, other means of suppressing the etching rate, and found that the anticorrosive agent having an acidic functional group and a basic functional group used in the polishing composition is effective. Specifically, the corrosion inhibitor having acidic functional groups (anionic functional groups) and basic functional groups (cationic functional groups) is adsorbed on the surface of metal oxides (for example, tungsten oxide), and is formed by coating the metal oxides Etching suppresses the coating and suppresses the dissolution of metal oxides. When the polishing composition containing such an anticorrosive agent is used, the dissolution (elution) of the substrate from the metal (for example, tungsten) is suppressed during polishing, and the surface roughness after polishing can be reduced. Further, in the case of using a No. 2013-42131 cationic bis 4 Level anticorrosive compound of Publication of Laid-Open Japanese, since the abrasive grains (e.g. Si ^-) Chek surface potential of the charged him a negative number, easily anticorrosive Adsorbed on the surface of abrasive grains, although in order to obtain a good anti-corrosion effect, a large amount of anti-corrosion agent must be used, but when a high-concentration anti-corrosion agent is used, the abrasive grains may aggregate and cause precipitation. In order to avoid agglomeration of abrasive grains, when reducing the amount of anti-corrosion agent used, a good effect of inhibiting the etching rate cannot be obtained. On the other hand, the anti-corrosion agent of the present invention already has a cationic basic functional group and an anionic acidic functional group. Since the cationic functional group is adsorbed on the metal oxide, the anionic functional group is also self-organized. In the case of metal oxides, a relatively small amount of anticorrosive agent can be used to prevent the abrasive particles from condensing on the surface of the metal oxide to form a film, and the etching rate can be suppressed.

Accordingly, according to the polishing composition of the present invention, the metal-containing layer (object to be polished) can be suppressed at a low etching rate and can be polished at a high polishing rate. In addition, since the elution of metal can be suppressed, when a layer containing a metal (object to be polished) is polished with the polishing composition of the present invention, the surface roughness (RMS) can be reduced, and a layer (substrate) having a flat surface can be obtained . Furthermore, according to the polishing composition of the present invention, even if the concentration of abrasive grains is not increased, the metal-containing layer (polishing object) can be suppressed at a low etching rate and can be polished on a smooth surface at a high polishing rate.

Hereinafter, an embodiment of the present invention will be described. However, the present invention is not limited to only the following embodiments.

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

〔Object to be polished〕

The object to be polished according to the present invention includes a metal layer. Here, the metal-containing layer may be one where at least the surface to be polished contains metal. Therefore, the metal-containing layer can be a substrate made of metal, a substrate having a metal-containing layer, or a metal-containing layer (for example, a polymer or other metal substrate is provided with a metal-containing layer or a metal The layer of the substrate). It is preferable that the layer containing a metal is a layer made of a metal (for example, a substrate) or a polishing object having a layer made of a metal (for example, a substrate).

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, etc. can be cited. The above-mentioned metal may be contained in the form of an alloy or a metal compound. These metals can be used alone or in combination of two or more kinds. The polishing composition of the present invention can be suitably used in the high-integration technology brought about by the miniaturization of the LSI manufacturing process, and is especially suitable for polishing materials for plugs or through holes around transistors. In addition, as the filling material, tungsten, copper, aluminum, and cobalt are preferable, and tungsten is more preferable. That is, according to the preferred form of the present invention, the metal is tungsten (that is, the polishing composition of the present invention is preferably used when it contains Polishing of the object to be polished of the tungsten layer).

〔Composition for polishing〕

The polishing composition of the present invention includes abrasive grains, an oxidizing agent, a dispersing medium, and an anticorrosive agent having an acidic functional group and a basic functional group. Hereinafter, each component of the polishing composition of the present invention will be described in detail.

(Abrasive grain)

The polishing composition of the present invention must contain abrasive grains. The abrasive particles contained in the polishing composition have the function of mechanically polishing the object to be polished, and increase the polishing rate of the object to be polished by the polishing composition.

The abrasive particles that can be used in the present invention may be any of inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of inorganic particles include particles made of metal oxides such as silicon dioxide, aluminum oxide, cerium oxide, and titanium oxide, silicon nitride particles, silicon carbide particles, and boron nitride particles. As a specific example of organic particles, for example, polymethyl methacrylate (PMMA) particles can be cited. The aforementioned abrasive grains can be used singly or as a mixture of two or more kinds. In addition, as the aforementioned abrasive grains, commercially available products can also be used as synthetic products.

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

The abrasive particles can be surface-modified. Normally, colloidal silica has a cheek potential close to zero under acidic conditions. Under acidic conditions, the silica particles will not electrically repel each other and easily cause agglomeration. In this regard, the acid strip The surface-modified abrasive particles have a relatively large negative value for the cheek potential, even under acidic conditions, they strongly repel each other and are well dispersed. 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 metals such as aluminum, titanium, or zirconium, or oxides thereof with abrasive grains, and doping them on the surface of the abrasive grains.

Among them, organic acid-immobilized silica is preferred, and organic acid-immobilized colloidal silica is particularly preferred. The immobilization of the organic acid on the surface of the colloidal silica contained in the polishing composition is performed, for example, by chemically bonding the functional groups of the organic acid on the surface of the colloidal silica. Merely allowing the coexistence of colloidal silica and organic acid, it is unable to achieve the immobilization of the organic acid of colloidal silica. If one of the organic acids, that is, sulfonic acid, is immobilized on colloidal silica, for example, the method described in "Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups", Chem. Commun. 246-247 (2003) can be carried out. Specifically, by coupling a silane coupling agent with a thiol group such as 3-mercaptopropyltrimethoxysilane to colloidal silica and then oxidizing the thiol group with hydrogen peroxide, the sulfonic acid can be immobilized on Colloidal silica on the surface. Or if carboxylic acid is immobilized on colloidal silica, for example, "Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel", Chemistry Letters, 3, 228-229 (2000) The method described is carried out. Specifically, by coupling a silane coupling agent containing photoreactive 2-nitrobenzyl ester to colloidal silica and irradiating it with light, the colloidal silica with carboxylic acid immobilized on the surface can be obtained.

The average degree of association (Degree of association) of the abrasive grains is preferably less than 5.0, more preferably 3.0 or less, and still more preferably 2.5 or less. As the average degree of connection of the abrasive grains becomes smaller, the surface roughness due to the shape of the abrasive grains can be made good. The average degree of connection of the abrasive grains is preferably 1.0 or more, more preferably 1.05 or more. As the average degree of connection of the abrasive grains increases, the polishing rate of the object to be polished by the polishing composition has an advantageous effect of increasing. The aforementioned average degree of correlation is obtained by dividing the value of the average secondary particle size of the abrasive grains by the value of the average primary particle size.

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 still more preferably 20 nm or more. In addition, 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 still more preferably 100 nm or less. If it is in such a range, the polishing rate of the polishing object with the polishing composition is increased, and the occurrence of surface defects on the surface of the polishing object after polishing with the polishing composition can be further suppressed. The average primary particle size of the abrasive grains is calculated based on the specific surface area of the abrasive grains measured by the 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 still more preferably 30 nm or more. In addition, the upper limit of the average secondary particle size of the abrasive grains is preferably 300 nm or less, more preferably 260 nm or less, and still more preferably 220 nm or less. If it is in such a range, the polishing rate of the object to be polished by the polishing composition is increased, and it is possible to further suppress the occurrence of surface defects on the surface of the object to be polished after polishing with the polishing composition. Here, the so-called secondary particles refer to particles formed by agglomeration of abrasive grains in the polishing composition. An example of the average secondary particle size of the secondary particles For example, it can be determined by dynamic light scattering method.

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. If it is in such a range, the surface roughness due to the shape of the abrasive grains can be made good. Furthermore, the aspect ratio is obtained by scanning electron microscope to obtain the smallest rectangle circumscribed to the image of abrasive particles. By dividing the length of the long side of the rectangle by the length of the short side of the same rectangle, the average value can be obtained. 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.

For the abrasive particles in the polishing composition, in the particle size distribution obtained by the laser diffraction scattering method, the particle diameter (D90) when the integrated particle weight from the side of the fine particles reaches 90% of the total particle weight is equal to The lower limit of the ratio D90/D10 of the diameter (D10) of the particle at 10% of the total particle weight of the whole particle is 1.1 or more, preferably 1.2 or more, and more preferably 1.3 or more. In addition, in the abrasive grains in the polishing composition, in the particle size distribution obtained by the laser diffraction scattering method, the particle diameter (D90) when the integrated particle weight from the side of the fine particles reaches 90% of the total particle weight Although the upper limit of the ratio D90/D10 to the diameter (D10) of the particle when it reaches 10% of the total particle weight of the whole particle is not particularly limited, it is preferably 2.04 or less. If it is in such a range, the surface roughness due to the shape of the abrasive grains can be made good.

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. In addition, 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 still more preferably 20% by mass or less. If it is within such a range, the polishing rate of the polishing object can be increased, and the cost of the polishing composition can be suppressed, and the occurrence of surface defects on the surface of the polishing object after polishing with the polishing composition can be further suppressed.

(Anti-corrosion agent)

The polishing composition of the present invention must contain an anticorrosive agent having an acidic functional group and a basic functional group. The presence of the aforementioned corrosion inhibitor suppresses the dissolution (elution) of the metal contained in the object to be polished, and smoothly (with low surface roughness (RMS)) polishes the layer containing the metal (the object to be polished). In addition, the etching rate can be kept low and the metal-containing layer (object to be polished) can be polished at a high polishing rate.

Examples of the acidic functional group of the anticorrosive agent of the present invention include carboxyl group, acid anhydride group, sulfo group, thiol group, phosphoric acid group, acidic phosphate ester group, phosphonic acid group, and these salt groups. From the viewpoint of film formation speed and film strength on the metal surface, it is preferable that the acidic functional group of the corrosion inhibitor is a carboxyl group, a phosphoric acid group, an acidic phosphoric acid ester group, and a salt group of these. The aforementioned acidic phosphate group refers to a part of the phosphorous bond hydroxyl group that has been alkoxylated. Examples of the alkoxy group include lower alkoxy groups such as methoxy, ethoxy, and propoxy. Preferably, the number of carbon atoms of the lower alkoxy group is 1-8.

As the basic functional group of the anticorrosive agent of the present invention, an amine group, an imine group, an ammonium base, and a heterocyclic group having a basic nitrogen atom can be cited. From the standpoint of dispersion stability as a composition, alkali, which is an anticorrosive agent, is preferred The functional groups are amino groups and ammonium bases. The aforementioned amino group may be any of a substituted or unsubstituted first-level amino group, a second-level amino group, or a third-level amino group. The aforementioned ammonium base may be a third-level ammonium base or a fourth-level ammonium base.

The acid value of the anticorrosive agent of the present invention is preferably 5 to 300 mgKOH/g, more preferably 5 to 150 mgKOH/g. The amine value of the anticorrosive agent of the present invention is preferably 5 to 300 mgKOH/g, more preferably 5 to 150 mgKOH/g. That is, according to the preferred form of the present invention, the acid value of the corrosion inhibitor is 5 to 150 mgKOH/g, and the amine value is 5 to 150 mgKOH/g. If 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 this specification, the "acid value" refers to the acid value per 1 g of the solid content of the anticorrosive agent of the present invention, which can be obtained by potentiometric titration in accordance with JIS-K-0070. The so-called "amine value" refers to the value of the amine value per 1g of the solid content of the anticorrosive agent of the present invention, which is obtained by potentiometric titration using a 0.1N aqueous hydrochloric acid solution, and converted into the equivalent of potassium hydroxide.

The acidic functional group is self-organized and adsorbs on the surface of the metal oxide, which is the object to be polished, and the basic functional group is adsorbed on the surface of the metal oxide, which is the object to be polished, which has a negative potential. It is an anticorrosive agent. A film is formed on the surface of the metal oxide. The coating made of the anticorrosive agent suppresses the dissolution (elution) of the metal, reduces the etching rate, and smoothly polishes the object to be polished.

The anticorrosion agent with the acidic functional group and the basic functional group of the present invention, Preferably, it is a polymer anticorrosion agent. In the case of using a polymer anticorrosion agent, the weight average molecular weight of the anticorrosion agent is usually 1,000 or more. The weight average molecular weight is preferably 1,000 to 100,000, more preferably 1,000 to 10,000. If the weight average molecular weight of the corrosion inhibitor is 1,000 or more, the acidic or basic functional groups of the corrosion inhibitor are adsorbed on the surface of the object to be polished, and the anticorrosion film can be effectively formed with the part of the polymer chain of the corrosion inhibitor. On the other hand, if the weight average molecular weight of the corrosion inhibitor is 100,000 or less, it prevents aggregation with abrasive grains. Furthermore, the above-mentioned weight average molecular weight can be measured by gel permeation chromatography (GPC) using polystyrene as a standard substance. As an anticorrosion agent, in the case of using a polymer anticorrosion agent, the bonding position of the acidic functional group and the basic functional group of the polymer is not particularly limited, and it can be the main chain, the side chain, or the main chain. And both sides of the side chain.

In one embodiment of the present invention, the corrosion inhibitor having acidic functional groups and basic functional groups is a compound represented by the following formula (1):

In the 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 substituted or unsubstituted octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, etc. , More specifically, for example, n-octyl, n-decyl, n-undecyl, lauryl (n-dodecyl), n-tridecyl, n-tetradecyl , N-pentadecyl, isotridecyl, s-tridecyl, t-tridecyl. 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 preferred. More preferably, it is a substituted or unsubstituted linear or branched alkyl group with 13 carbon atoms (n-tridecyl, isotridecyl, s-tridecyl, t-tridecyl) .

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 ethylene, n-propylene, i-propylene, n-butylene, i-butylene, n-pentylene, n-hexylene, etc., and the plural R ³ can be They are the same or different. Among these, from the viewpoint of more effectively exhibiting the effects of the present invention, R ³ is preferably a vinyl group.

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

* Indicates the position of bonding with ^{R 1} or R ² in formula (1).

X ⁺ is an ammonium ion, a first-stage ammonium ion, a second-stage ammonium ion, a third-stage ammonium ion, or a fourth-stage ammonium ion. Specific examples include ammonium ion, methylammonium ion, dimethylammonium ion, trimethylethylammonium ion, trimethylpropylammonium ion, trimethylhexylammonium ion, tetrapentylammonium ion, etc. Among these, X ⁺ is preferably 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, and the like. 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) Ears = 70), polyoxyethylene lauryl ether ammonium phosphate (addition moles of ethylene oxide = 20), dipolyoxyethylene (C12-15) alkyl ether ammonium phosphate (addition moles of ethylene oxide) Ears = 2), polyoxyethylene (C12-15) alkyl ether ammonium phosphate (addition moles of ethylene oxide = 2), sodium dipolyoxyethylene lauryl ether phosphate (addition moles of ethylene oxide =10), dipolyoxyethylene (C12-15) alkyl ether ammonium phosphate (addition molar number of ethylene oxide = 4), dipolyoxyethylene (C12-15) alkyl ether ammonium phosphate (addition of ethylene oxide Mole number = 6), dipolyoxyethylene (C12-15) alkyl ether ammonium phosphate (addition mole number of ethylene oxide = 10), polyoxyethylene lauryl ether ammonium phosphate (addition mole number of ethylene oxide) Ears = 10), polyoxyethylene (C12-15) alkyl ether ammonium phosphate (addition moles of ethylene oxide = 4), etc. Furthermore, the "C12-15" in the name of the above-mentioned compound means those with 12 to 15 carbon atoms in the alkyl group and mixtures thereof.

The anti-corrosion agent related to the present invention may be used alone or in combination of two or more kinds.

For the anticorrosive agent of the present invention, synthetic products can be used, or commercially available products can also be used.

As the corrosion inhibitor having acidic functional groups and basic functional groups, in the case of using a polymer corrosion inhibitor, synthetic polymers can be used. As can The synthetic polymers used are typically vinyl polymerization polymers and polycondensation polymers. The acidic functional group and the basic functional group in the vinyl polymer polymer with acidic functional group and basic functional group are respectively derived from monomers during vinyl polymerization. Examples of vinyl monomers having acidic functional groups include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, crotonic acid, fumaric acid, monoalkyl maleate, Vinyl monomers containing carboxyl groups such as monoalkyl fumarate. Examples of monomers having basic functions include N,N-dimethylaminoethyl (meth)acrylate, N-methylaminoethyl (meth)acrylate, N,N-di Ethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, Nt-butylaminoethyl (meth)acrylate, N,N- Dimethylaminobutyl (meth)acrylate and other amino alkyl-containing acrylates or amino alkyl-containing methacrylates, such as N,N-dimethylaminoethyl (meth) Yl)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, etc., containing aminoalkyl acrylamide or aminoalkyl containing methacrylamide. Still, the term "(meth)acryloyl" means "acryloyl or methacryloyl". After separately polymerizing vinyl monomers containing acidic functional groups and vinyl monomers containing basic functional groups, or block polymerization, or polymerizing only one side of these, the other side can be graft-polymerized Way to proceed. Examples of polycondensation polymers include polyurethane, polyester, polyoxyalkylene, polyoxyalkylene/polyester copolymer, polyamide, phenol resin, urea resin, melamine resin, polycarbonate, cyclic Oxygen resin, alkyd resin, polyalkyleneimine (polyethyleneimine, etc.), polyvinylpyrrolidone, polyallylamine, polyether polyamine (polyoxy Nitrogen-containing polymers such as ethylene polyamine, etc.).

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 still more preferably 0.005% by mass or more. In addition, 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 still more preferably 0.05% by mass or less. If it is within such a range, the polishing speed of the polishing object can be further increased, and the occurrence of surface defects on the surface of the polishing object after polishing with the polishing composition can be more suppressed.

(Oxidant)

The polishing composition of the present invention must contain an oxidizing agent. Although the oxidizing agent of the present invention is not particularly limited, it is preferably peroxide. That is, according to the preferred embodiment of the present invention, the oxidizing agent is peroxide. As specific examples of such peroxides, although not limited to the following, examples include hydrogen peroxide, peracetic acid, percarbonate, carbamide peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, and monopersulfuric acid. Potassium and potassium peroxymonosulfate (Oxone), etc. The above-mentioned oxidants can be used alone or in combination of two or more kinds. That is, according to the preferred form of the present invention, the peroxide is selected from hydrogen peroxide, peracetic acid, percarbonate, carbamide peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, potassium monopersulfate and At least one of the group consisting of potassium peroxymonosulfate (Oxone). The oxidizing agent is more preferably persulfate (sodium persulfate, potassium persulfate, ammonium persulfate) and hydrogen peroxide, particularly preferably hydrogen peroxide.

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 still more preferably 0.01% by mass or more. As the content of the oxidant increases, there is an advantage of increasing the polishing speed of the polishing composition. In addition, 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 still more preferably 1% by mass or less. As the content of the oxidant decreases, in addition to suppressing the material cost of the polishing composition, it also has the advantage of reducing the processing of the polishing composition after polishing use, and also reducing the load of waste liquid treatment. In addition, it has the advantage of not easily causing excessive oxidation on the surface of the object to be polished, and reducing the roughness of the metal surface after polishing.

Furthermore, since an oxidizing agent is used to form an oxide film on the surface of the metal-containing layer, the oxidizing agent is preferably added immediately before polishing.

(Dispersed medium)

The polishing composition of the present invention contains a dispersion medium in order to disperse or dissolve each component. Here, although the dispersion medium is not particularly limited, it is preferably water. From the viewpoint of inhibiting the effect of hindering other components, it is more preferably water that contains no impurities as much as possible. Specifically, pure water or ultra-pure water that removes foreign matter through a filter after ion exchange resin removes impurity ions. Water, or distilled water.

(Other ingredients)

As described above, although the polishing composition of the present invention must contain abrasive grains, an oxidizing agent, an anticorrosive agent, and a dispersing medium, it may contain other additives in addition to the above-mentioned components. Here, as other additives, it is not particularly limited It is possible to use additives that are usually added to polishing compositions. Specifically, pH adjusters, complexing agents, metal anticorrosive agents, preservatives, antifungal agents, reducing agents, water-soluble polymers, organic solvents for dissolving poorly soluble organic substances, and the like can be cited. In addition, the polishing composition of the present invention, for example, does not substantially contain the second-level compound described in JP 2013-42131 A. In addition, the polishing composition of the present invention does not substantially contain an iodine compound (for example, potassium iodate) that can be a trigger for the generation of iodine gas. Here, the term "substantially not included" 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, and preferably 5% by mass or less ( Lower limit: 0% by mass).

Hereinafter, among the above-mentioned other additives, the pH adjuster, the complexing agent, the metal anticorrosive agent, the anticorrosive agent, and the 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 pH adjuster. In order to adjust the pH of the polishing composition to a desired value, if necessary, the pH adjuster used may be either an acid or a base, and may also be either an inorganic compound or an organic compound. Specific examples of acids include, for example, 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, oxalic acid, 2-methylbutyric acid, n -Hexanoic acid, 3,3-dimethylbutanoic acid, 2-ethylbutanoic acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid , Benzoic acid, glycolic acid, salicylic acid 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 Organic acids such as methanesulfonic acid, ethanesulfonic acid and 2-isethionic acid (Isethionic acid). Specific examples of the base include amines such as ammonia, ethylenediamine, and piperazine, and fourth-level ammonium salts such as tetramethylammonium and tetraethylammonium. These pH adjusters can be used alone or in combination of two or more kinds.

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.

In addition, the upper limit of the pH of the polishing composition is preferably 7 or less, more preferably 5 or less, and particularly preferably 4.0 or less. As the pH of the polishing composition decreases, the polishing rate of the metal that is the object to be polished is increased.

(Dissolving agent)

If necessary, the compounding agent can be included in the polishing composition to chemically etch the surface of the object to be polished, which can more effectively increase the polishing rate of the object to be polished by the polishing composition.

Examples of the complexing agent that can be used include, for example, inorganic acids or their salts, organic acids or their salts, nitrile compounds, amino acids, and chelating agents. These modifiers can be used alone or in combination of two or more kinds. In addition, a commercially available product or a synthetic product can be used for this dissolving agent.

As the complexing agent, the salt of the aforementioned inorganic acid or the aforementioned organic acid can be used. Especially the use of weak acid and strong base salt, strong acid and weak base salt, or weak acid and In the case of weak base salts, the buffering effect of pH can be expected. Examples of such salts include potassium chloride, sodium sulfate, potassium nitrate, potassium carbonate, potassium tetrafluoroborate, potassium pyrophosphate, potassium oxalate, trisodium citrate, (+)-potassium tartrate, potassium hexafluorophosphate Wait.

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

Specific examples of amino acids include glycine, α-alanine, β-alanine, N-methylglycine, N,N-dimethylglycine, 2-aminobutyric acid, Valine, Valine, Leucine, Norleucine, Isoleucine, Phenylalanine, Proline, Creatine, Ornithine, Lysine, Taurine, Seramine Acid, hydroxybutyric acid, serine-like acid, tyrosine, diglycine (Bicine), tricine (Tricine), 3,5-diiodo-tyrosine, β-(3,4- Dihydroxyphenyl)-alanine, thyroxine, 4-hydroxy-proline, cysteine, methionine, ethionine, lanthionine, cystathionine, cystine, sulfo Alanine, aspartic acid, glutamic acid, S-(carboxymethyl)-cysteine, 4-aminobutyric acid, aspartic acid, glutamic acid, azoserine, refined Amino acid, canavalinic acid, citrulline, delta-hydroxy-lysine, creatine, histidine, 1-methyl-histidine, 3-methyl-histidine, and tryptophan.

Specific examples of the chelating agent include nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, N,N,N-trimethylenephosphonic acid, ethylenediamine-N,N,N', N'-tetramethylene sulfonic acid, trans-cyclohexanediaminetetraacetic acid, 1,2-diaminopropanetetraacetic acid, glycol ether diaminetetraacetic acid, ethylenediamine o-hydroxybenzene Glycolic acid, ethylenediamine disuccinic acid (SS body), N-(2-carboxylate ethyl)-L-aspartic acid, β-alanine diacetic acid, 2-phosphoranylbutane-1, 2,4-Tricarboxylic acid, 1-hydroxyethylene-1,1-diphosphonic acid, N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid, 1, 2-Dihydroxybenzene-4,6-disulfonic acid, etc.

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

The content (concentration) of the complexing agent when the polishing composition contains the complexing agent is not particularly limited. For example, the lower limit of the content (concentration) of the dissolving agent is effective even in a small amount. Although not particularly limited, it is preferably 0.001 g/L or more, more preferably 0.01 g/L or more, and still more preferably 1 g/L. Above L. In addition, the upper limit of the content (concentration) of the dissolving agent is preferably 20 g/L or less, more preferably 15 g/L or less, and still more preferably 10 g/L or less. If it is in such a range, the polishing speed of the polishing object is increased, and it is also advantageous in improving the smoothness of the surface of the polishing object after polishing with the polishing composition.

(Metal corrosion inhibitor)

Secondly, if necessary, the metal anticorrosion agent that can be included in the polishing composition is a metal anticorrosion agent other than the anticorrosion agent having the above-mentioned acidic functional group and basic functional group. By preventing the dissolution of the metal, it can inhibit the roughness of the polished surface. The deterioration of the surface condition. However, because of the The anticorrosion agent functions as a metal anticorrosion agent, and the polishing composition of the present invention can sufficiently inhibit and prevent the dissolution of the metal even if the metal anticorrosion agent is not added separately.

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

As specific examples of heterocyclic compounds that can be used as metal corrosion inhibitors, for example, pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, pyridine compounds, pyrazine compounds, pyridazine compounds, and nitrogen indoles ( Pyrindine compound, indolizine compound, indole compound, isoindole compound, indazole compound, purine compound, quinolizine compound, quinoline compound, isoquinoline compound, naphthyridine compound, phthalazine (Phthalazine) compounds, quinoxaline compounds, quinazoline compounds, cinnoline compounds, pteridine compounds, thiazole compounds, isothiazole compounds, oxazole compounds, isoxazole compounds, furoxan compounds and other nitrogen-containing heterocyclic compounds.

Furthermore, when specific examples are given, examples of pyrazole compounds include, for example, 1H-pyrazole, 4-nitro-3-pyrazolecarboxylic acid, 3,5-pyrazolecarboxylic acid, and 3-amino-5 -Phenylpyrazole, 5-amino-3-phenylpyrazole, 3,4,5-tribromopyrazole, 3-aminopyrazole, 3,5-dimethylpyrazole, 3,5- Dimethyl-1-hydroxymethylpyridine Azole, 3-methylpyrazole, 1-methylpyrazole, 3-amino-5-methylpyrazole, 4-amino-pyrazolo[3,4-d]pyrimidine, isopurinol, 4 -Chloro-1H-pyrazolo[3,4-D]pyrimidine, 3,4-dihydroxy-6-methylpyrazolo(3,4-B)-pyridine, 6-methyl-1H-pyrazole And [3,4-b]pyridine-3-amine and so on.

Examples of imidazole compounds include 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)benzo (Benz) imidazole, 2-hydroxybenzo (Benz) imidazole, 2-phenyl benzo (Benz) imidazole, 2,5-dimethylbenzo (Benz) imidazole, 5-methyl Benzimidazole, 5-nitrobenzo (Benz) imidazole, etc.

As an example of the triazole compound, 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-carboxylic acid ester, 1,2,4-triazole-3-carboxylic acid, 1,2,4-triazole-3-carboxylic acid methyl ester, 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-1,2,4-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-amine Group-3,5-dimethyl-4H-1,2,4-triazole, 4-amino-3,5-diheptyl-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)aminomethyl]-5-methyl Benzotriazole, 1-[N,N-bis(hydroxyethyl)aminomethyl]-4-methylbenzotriazole, etc.

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

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

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 Indole, 7-hydroxy-1H-indole, 4-methoxy-1H-indole, 5-methoxy-1H-indole, 6-methoxy-1H-indole, 7-methoxy- 1H-indole, 4-chloro-1H-indole, 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 Base-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 Indole, 2,3-dimethyl-1H-indole, 5-amino-2,3-dimethyl-1H-indole, 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 so on.

Among them, the heterocyclic compound is preferably a triazole compound, particularly preferably 1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole , 1-[N,N-bis(hydroxyethyl)aminomethyl]-5-methylbenzotriazole, 1-[N,N-bis(hydroxyethyl)aminomethyl]-4- Methylbenzotriazole, 1,2,3-triazole, and 1,2,4-triazole. Since these heterocyclic compounds have a high chemical or physical attraction to the surface of the object to be polished, a strong protective film can be formed on the surface of the object to be polished. This point is advantageous in improving the smoothness of the surface of the polishing object after polishing with the polishing composition of the present invention.

In addition, surfactants used as metal anticorrosive agents include anionic surfactants, cationic surfactants, and amphoteric surfactants.

Examples of anionic surfactants include, for example, polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl sulfate, alkyl sulfate, polyoxyethylene alkyl ether sulfuric acid, alkyl ether sulfuric acid, and alkyl benzene sulfonate. Acid, alkyl phosphate, polyoxyethylene alkyl phosphate, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthyl sulfonic acid, alkyl diphenyl ether disulfonic acid, and the like The salt and so on.

Examples of cationic surfactants include, for example, alkyl trimethyl ammonium salts, alkyl dimethyl ammonium salts, alkyl benzyl dimethyl ammonium salts, and alkyl amines. Salt etc.

As an example of an amphoteric surfactant, an alkyl betaine, an alkyl amine oxide, etc. are mentioned, for example.

Specific examples of nonionic surfactants include, for example, polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers, sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, and polyoxyethylene fatty acid esters. Vinyl alkyl amines, and alkyl alkanol amines. Among them, 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 on the surface of the object to be polished, a strong protective film can be formed on the surface of the object to be polished. This point is advantageous in improving the flatness of the surface of the polishing object after polishing with the polishing composition of the present invention.

The content (concentration) of the metal anticorrosion agent when the polishing composition contains the metal anticorrosion agent is not particularly limited. For example, the lower limit of the content (concentration) of the metal anticorrosive agent is preferably 0.001 g/L or more, more preferably 0.005 g/L or more, and still more preferably 0.01 g/L or more. In addition, the upper limit of the content (concentration) of the metal anticorrosive agent is preferably 10 g/L or less, more preferably 5 g/L or less, and still more preferably 2 g/L or less. If it is in such a range, it is possible to prevent the dissolution of the metal and suppress the deterioration of the surface condition such as roughness of the polished surface.

(Preservatives and antifungal agents)

Furthermore, as an antiseptic and an antifungal agent that may be included in the polishing composition as necessary, for example, 2-methyl-4-isothiazolin-3-one or 5-chloro-2-methyl Isothiazoline preservatives such as 4-isothiazolin-3-one, paraoxy benzoic acid esters, and phenoxyethanol. These preservatives and antifungal agents can be used alone or in combination of two or more.

〔Method of manufacturing polishing composition〕

The manufacturing method of the polishing composition of the present invention is not particularly limited. For example, it can be obtained by stirring and mixing abrasive grains, an oxidizing agent, an anticorrosive agent, and if necessary other additives in a dispersion medium (for example, water). Still, as mentioned above, since the oxidant promotes the formation of an oxide film on the surface of the metal-containing layer, it includes the step of adding abrasive grains, anti-corrosion agents, and other additives if necessary to a dispersing medium (such as water) to prepare a preliminary composition , It is better than the manufacturing method of the polishing composition in the step of adding the oxidizing agent to the aforementioned preliminary composition just before the polishing. In one embodiment, a method for manufacturing a polishing composition is provided, which includes the steps of mixing abrasive grains, an anticorrosive agent with a dispersion medium, preparing a preliminary composition, and adding an oxidizing agent to the preliminary composition just before polishing step.

Although the temperature when mixing each component is not particularly limited, it is preferably 10-40°C, and heating may be performed to increase the dissolution rate. In addition, the mixing time is not particularly limited as long as it can be uniformly mixed.

[Lapping method and substrate manufacturing method]

As described above, the polishing composition of the present invention is suitable for use in polishing of a metal-containing layer (object to be polished). Therefore, the present invention also provides a polishing method, which uses the present invention to polish an object having a metal-containing layer. The polishing composition is used for polishing. In addition, the present invention provides a method of manufacturing a substrate, which includes the step of polishing a layer (a polishing object) containing a metal by the aforementioned polishing method. In addition, the metal used in the aforementioned polishing method and substrate manufacturing method is preferably tungsten.

As the polishing device, a holder for holding a substrate with the object to be polished, a motor capable of changing the number of revolutions, etc. are installed, and a general polishing device with a polishing platform to which a polishing pad (polishing cloth) can be attached can be used.

As the aforementioned polishing pad, general non-woven fabric, polyurethane, porous fluororesin, and the like can be used without particular limitation. Among the polishing pads, it is better to perform groove processing that does not accumulate polishing liquid.

Regarding the grinding conditions, for example, the rotation speed of the grinding platform is preferably 10 to 500 rpm. The pressure (polishing pressure) on the substrate with the polishing object is preferably 0.5-10 psi. The method of supplying the polishing composition to the polishing pad is also not particularly limited. For example, a continuous supply method such as a pump is used. Although this supply amount is not limited, it is preferable that the surface of the polishing pad is often coated with the polishing composition of the present invention.

After polishing, the substrate is washed in running water, and the water droplets attached to the substrate are shaken off and dried by a spin dryer or the like to obtain a substrate with a metal-containing layer.

The polishing composition of the present invention may be a one-liquid type or a multi-liquid type that is initially a two-liquid type. As mentioned above, the oxidant promotes the formation of an oxide film on the surface of the metal-containing layer. Therefore, it is preferably composed of a first liquid containing abrasive grains, an anticorrosive agent, a dispersing medium (such as water), and other additives if necessary, and a second liquid containing an oxidizing agent and a dispersing medium (such as water) as necessary. It constitutes a two-component type. In addition, the polishing composition of the present invention can be prepared by diluting the original liquid of the polishing composition to a dilution solution such as water, for example, 10 times or more.

The polishing composition of the present invention is preferably used in the metal polishing step, especially the tungsten polishing step. Furthermore, the step of tungsten grinding is roughly divided into the main grinding step of grinding to remove most of the layer containing tungsten, and the buffing grinding step of polishing the layer containing tungsten and the insulator layer, preferably In order to use the polishing composition of the present invention for polishing and polishing.

[Example]

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 to only the following embodiments. However, unless otherwise stated, "%" and "parts" mean "mass %" and "parts by mass" respectively. In addition, in the following examples, unless otherwise specified, the operation is performed under the conditions of room temperature (25° C.)/relative humidity 40-50% RH.

<Example>

In 1L of pure water, by making the anticorrosive agent shown in Table 1 below 0.01% by mass with respect to the final polishing composition, the abrasive particles (sulfonic acid immobilized colloidal silica; average primary particle size: 30nm, average Secondary particle size: 60nm, aspect ratio: 1.24, D90/D10: 2.01) is added in an amount of 2.0% by mass relative to the final polishing composition to form the polishing composition Maleic acid aqueous solution (30% by mass) was added so that the pH became 2.1 to prepare each preliminary composition. In addition, just before polishing the tungsten wafer, as an oxidizing agent, hydrogen peroxide water (30% by mass) was added to the preliminary composition while stirring such that the amount of the final polishing composition was 0.2% by mass. To prepare each polishing composition. The pH of the composition (liquid temperature: 25°C) was confirmed with a pH meter (Model: LAQUA, manufactured by Horiba Manufacturing Co., Ltd.).

For each polishing composition obtained above, the removal rate (Å/min), the etching rate (Å/min), and the surface roughness (RMS) were evaluated according to the following method. As Examples 1-11 and Comparative Examples 1-8. The results are shown in Table 1 below.

<Measurement of Removal Rate>

Using each polishing composition, the polishing object was polished under the following polishing conditions. The thickness (film thickness) of the polishing object before and after polishing was measured with a manual sheet resistor (VR-120, manufactured by Hitachi Kokusai Electric Co., Ltd.). As for the calculation method of the polishing rate described below, the polishing rate (Removal Rate) (Å/min) is obtained by dividing the difference between the thickness (film thickness) of the object to be polished before and after polishing by the polishing time. Still, a tungsten wafer (size: 32mm×32mm) is used as the object to be polished.

(Grinding conditions)

Grinding machine: One-sided CMP grinding machine (ENGIS)

Polishing pad: Polyurethane pad (IC1010: manufactured by Rohm and Haas)

Pressure: 2.0psi

The number of rotations of the platen (platform): 70rpm

Number of revolutions of the head (carrier): 70rpm

Flow rate of grinding composition: 150ml/min

Grinding time: 60sec

(Calculation method of grinding speed)

The polishing rate (polishing rate) (Å/min) is calculated by the following formula (1).

<Measurement of Etching Rate>

The etching test was performed by the following operation. That is, 300 mL of each polishing composition was put into a sample container, and the object to be polished was immersed for 10 minutes while stirring at 300 rpm. The immersed wafers were rinsed with pure water for 30 seconds, and dried by blowing air from an air gun. The thickness (film thickness) of the object to be polished before and after the etching test was measured with a manual sheet resistor (VR-120, Hitachi International Electric). As for the calculation method of the etching rate described below, the etching rate (Etching Rate) (Å/min) is obtained by dividing the difference in the thickness (film thickness) of the object to be polished before and after the etching test by the etching test time. Still, a tungsten wafer (size: 32mm×32mm) is used as the object to be polished.

(Calculation method of etching rate)

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

<Measurement of Surface Roughness (RMS)>

In the same manner as the above-mentioned [Measurement of Polishing Rate (Removal Rate)], each polishing composition was used to polish the object to be polished. The surface roughness (RMS) of the polished surface of the polished object after polishing was measured using a scanning probe microscope (SPM). Still, use NANO-NAVI2 manufactured by Hitachi High-Tech as SPM. The cantilever system uses the SI-DF40P2 measurement system to perform 3 times with a scanning frequency of 0.86 Hz, X: 512pt, and Y: 512pt, and the average value of these is defined as the surface roughness (RMS).

In Table 1, the so-called 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 means a compound with 130 moles of addition of ethylene oxide. "C12-15" means alkyl groups with 12 to 15 carbon atoms and mixtures thereof.

From the results of Table 1 above, it is understood that the polishing composition (Comparative Example 1) that does not contain the corrosion inhibitor, or the polishing composition that contains the corrosion inhibitor that does not have both an acidic functional group and a basic functional group (Comparative Examples 2 to 8) There is a level where the etching rate is high and the surface roughness of the polishing object is also large. On the other hand, I learned that by using The polishing composition (Examples 1 to 11) of the anticorrosive agent for functional groups and basic functional groups suppresses the etching rate of metal (tungsten) substrates. In addition, it is shown that by polishing with the polishing composition of the present invention, a substrate having a polished surface with a smaller surface roughness (RMS) (that is, excellent in smoothness) is obtained. Furthermore, it is also understood that the greater the added molar number of ethylene oxide of the anticorrosive agent contained in the polishing composition, the more the etching rate can be suppressed and the polishing can be performed at a high polishing rate.

Claims (9)

A polishing composition used for polishing a polishing object having a metal-containing layer, characterized in that the metal is tungsten, contains abrasive grains, an oxidizer, and a dispersion medium, and has an acidic function Anti-corrosion agent of base and basic functional group, the aforementioned anti-corrosion agent 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 with 8 to 16 carbon atoms, and 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 with 2-6 carbon atoms, and the plural R ³ may be the same or different respectively, n is an integer of 2 to 200, and * means the same as R ^{1 in formula (1)} Or where R ^{2 is} bonded, X ⁺ is an ammonium ion, a first-order ammonium ion, a second-order ammonium ion, a third-order ammonium ion, or a fourth-order ammonium ion. Such as the polishing composition of claim 1, wherein the acid value of the aforementioned anticorrosive agent is 5 to 150 mgKOH/g, and the amine value is 5 to 150 mgKOH/g. Such as the polishing composition of claim 1 or 2, wherein the aforementioned oxygen The chemical agent is peroxide. The polishing composition of claim 3, wherein the aforementioned peroxide is selected from hydrogen peroxide, peracetic acid, percarbonate, carbamide peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, and potassium monopersulfate And at least one of the group consisting of potassium peroxymonosulfate (Oxone). The polishing composition of claim 1 or 2, wherein the abrasive grains are organic acid-immobilized silica. Such as the polishing composition of claim 1 or 2, which further contains a pH adjuster. A method for manufacturing a polishing composition as described in claim 1, comprising: mixing abrasive grains, an anticorrosive agent with a dispersing medium to prepare a preliminary composition, and adding an oxidizing agent to the preliminary composition just before polishing step. A polishing method for polishing an object to be polished having a metal-containing layer with the polishing composition according to any one of claims 1 to 6. A method for manufacturing a substrate, which includes the step of polishing with the polishing method of claim 8.