JP5030431B2 - Polishing composition - Google Patents

Description

  The present invention relates to a polishing composition, and more particularly to a polishing composition used in a wiring formation step in semiconductor device manufacturing.

  In the development of semiconductor devices typified by semiconductor integrated circuits (hereinafter referred to as “LSI” where appropriate), in recent years, miniaturization and stacking of wiring has led to higher density and higher integration for miniaturization and higher speed. It has been demanded. For this purpose, various techniques such as chemical mechanical polishing ((Chemical Mechanical Polishing, hereinafter referred to as “CMP” as appropriate)) have been used, which is used for processing a film to be processed such as an interlayer insulating film. This technique is essential when performing surface planarization, plug formation, formation of embedded metal wiring, etc., and this technique is used to smooth the substrate and remove excess metal thin film during wiring formation (for example, , See Patent Document 1).

  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 liquid, press the surface of the substrate (wafer) against the pad, In a state where pressure (polishing pressure) is applied, both the polishing platen and the substrate are rotated, and the surface of the substrate is flattened by the generated mechanical friction.

Conventionally, tungsten and aluminum have been widely used in interconnect structures as wiring metals. However, LSIs using copper, which has lower wiring resistance than these metals, have been developed with the aim of achieving higher performance. As a method of wiring this copper, for example, a damascene method described in Patent Document 2 is known. Further, a dual damascene method in which a contact hole and a wiring groove are simultaneously formed in an interlayer insulating film and a metal is embedded in both has been widely used. As a target material for copper wiring, a high-purity copper target of five nines or more has been shipped.
However, in recent years, with the miniaturization of wiring aiming at further higher density, it has become necessary to improve the conductivity and electronic characteristics of copper wiring, and accordingly, a copper alloy in which a third component is added to high-purity copper is required. It is also beginning to be considered for use. At the same time, there is a need for high-speed metal polishing means that can exhibit high productivity without contaminating these high-definition and high-purity materials. In copper metal polishing, because it is a particularly soft metal, only the center is polished deeper and a dish-like dent is formed (dishing), and the surface of a plurality of wiring metal surfaces forms a dish-shaped recess. (Erosion) and polishing scratches (scratches) are likely to occur, and a highly accurate polishing technique is increasingly required.

Furthermore, in recent years, the diameter of wafers during LSI manufacturing has been increased for the purpose of improving productivity. Currently, the diameter of 200 mm or more is widely used, and the manufacture of 300 mm or more has started. As the size of the wafer increases, a difference in polishing rate between the central portion of the wafer and the peripheral portion tends to occur, and the demand for uniformity of polishing within the wafer surface is becoming increasingly severe.
As a chemical polishing method in which mechanical polishing means is not applied to copper and a copper alloy, a method described in Patent Document 3 is known. However, the chemical polishing method using only the chemical dissolution action has a greater problem in flatness due to the occurrence of dishing of the recess, that is, the occurrence of dishing, as compared with CMP in which the metal film of the protrusion is selectively chemically and mechanically polished. Remaining.

  In addition, when copper wiring is used in LSI manufacturing, a diffusion preventing layer called a barrier layer is generally provided between the wiring portion and the insulating layer in order to prevent copper ions from diffusing into the insulating material. The barrier layer is formed of one or more layers made of a barrier material selected from TaN, TaSiN, Ta, TiN, Ti, Nb, W, WN, Co, Zr, ZrN, Ru, and CuTa alloy. Since these barrier materials themselves have conductive properties, the barrier material on the insulating layer must be completely removed in order to prevent the occurrence of errors such as leakage current. This removal processing is achieved by a method similar to the bulk polishing of the metal wiring material (barrier CMP).

  Further, in bulk polishing of copper, dishing is likely to occur particularly in a wide metal wiring portion. Therefore, in order to achieve final planarization, it is desirable to be able to adjust the amount of polishing and removal in the wiring portion and the barrier portion. For this reason, it is desired that the polishing liquid for barrier polishing has an optimum copper / barrier metal polishing selectivity. Further, since the wiring pitch and the wiring density are different in each level of the wiring layer, it is further desirable that the polishing selectivity can be adjusted as appropriate.

  The metal polishing composition (metal polishing liquid) used for CMP generally contains solid abrasive grains (eg, alumina, silica) and an oxidizing agent (eg, hydrogen peroxide, persulfuric acid). It is considered that the basic mechanism of CMP using such a metal polishing liquid is that the metal surface is oxidized by an oxidizing agent and the oxide film is removed by abrasive grains, and polishing is performed. This is described in Patent Document 1.

  However, when CMP is performed using a metal polishing liquid containing such solid abrasive grains, polishing scratches, a phenomenon in which the entire polishing surface is polished more than necessary (thinning), and the polishing metal surface on the plate There are cases where a phenomenon of bending (dishing), an insulator between metal wirings is unnecessarily polished, and a phenomenon that a plurality of wiring metal surfaces bend on a plate (erosion). In addition, in a cleaning process usually performed to remove the polishing liquid remaining on the semiconductor surface after polishing, the cleaning process becomes complicated by using a polishing liquid containing solid abrasive grains. In order to treat (waste liquid), there is a problem in terms of cost, for example, it is necessary to settle and separate solid abrasive grains.

  As one means for solving these problems, for example, a metal surface polishing method using a combination of a polishing liquid not containing abrasive grains and dry etching is disclosed in Non-Patent Document 2, and Patent Document 4 discloses a method of peroxidation. A metal polishing fluid comprising hydrogen / malic acid / benzotriazole / ammonium polyacrylate and water is disclosed. According to these methods, the metal film on the convex portion of the semiconductor substrate is selectively CMPed, and the metal film is left in the concave portion to obtain a desired conductor pattern. Since CMP proceeds by friction with a polishing pad that is much mechanically softer than that containing conventional solid abrasive grains, the occurrence of scratches is reduced. However, there is a drawback that it is difficult to obtain a sufficient polishing rate due to a decrease in physical polishing power.

On the other hand, a polishing liquid containing abrasive grains has a feature that a high polishing rate can be obtained, but there are problems of dishing due to agglomeration of abrasive grains, generation of scratches and deterioration of polishing performance (shelf life). For example, Patent Document 5 discloses a technique in which a part or all of the surface of colloidal silica produced by a method of removing alkali from an alkali silicate aqueous solution is coated with aluminum. Colloidal silica is disclosed. However, the polishing liquid disclosed in the patent document has an insufficient shelf life when a performance guarantee longer than 3 months is required. Further, when the pH of the polishing liquid exceeds 6, there is a problem that the colloidal silica abrasive grains are agglomerated and scratches are increased.
US Pat. No. 4,944,836 JP-A-2-278822 JP 49-122432 A JP 2001-127019 A JP 2003-197573 A Journal of Electrochemical Society, 1991, 138, 11, 3460-3464 Journal of Electrochemical Society, 2000, 147, 10, 3907-3913

  An object of the present invention is to provide a polishing composition having excellent polishing performance and a long shelf life.

  As a result of intensive studies on the problems related to the polishing composition, the present inventor has found that the problems can be solved by the following metal polishing composition, and has completed the present invention.

<1> Colloidal silica obtained by hydrolyzing alkoxysilane, and a part of the surface of which is covered with aluminum atoms; 2-methyl-4-isothiazolin-3-one and 5 A compound having at least one isothiazolin-3-one skeleton selected from -chloro-2-methyl-4-isothiazolin-3-one, glycine, and no substituent on the nitrogen atom forming the tetrazole ring And at the 5-position of tetrazole, a substituent selected from the group consisting of a sulfo group, an amino group, a carbamoyl group, a carbonamido group, a sulfamoyl group and a sulfonamido group, or a hydroxy group, a carboxy group, a sulfo group, an amino group A group consisting of a group, a carbamoyl group, a carbonamido group, a sulfamoyl group, and a sulfonamido group A polishing composition comprising a heteroaromatic ring compound which is a tetrazole derivative having an alkyl group substituted with at least one selected substituent .
<2> Colloidal silica obtained by hydrolyzing alkoxysilane and having a part of its surface covered with aluminum atoms; 2-methyl-4-isothiazolin-3-one and 5 A compound having at least one isothiazolin-3-one skeleton selected from -chloro-2-methyl-4-isothiazolin-3-one, glycine and a nitrogen atom forming a 1,2,3-triazole ring; There are no substituents, and hydroxy groups, carboxy groups, sulfo groups, amino groups, carbamoyl groups, carbonamido groups, sulfamoyl groups, and sulfones at the 4-position and / or 5-position of 1,2,3-triazole A substituent selected from the group consisting of amide groups, or a hydroxy group, carboxy group, sulfo group, amino group, carbamoyl group, A heteroaromatic compound which is a 1,2,3-triazole derivative having an alkyl group or an aryl group substituted with at least one substituent selected from the group consisting of a amide group, a sulfamoyl group, and a sulfonamide group, or There is no substituent on the nitrogen atom forming the 1,2,4-triazole ring, and a sulfo group, a carbamoyl group, a carbonamido group is present at the 2-position and / or 5-position of the 1,2,4-triazole. Or a substituent selected from the group consisting of a sulfamoyl group and a sulfonamido group, or a group selected from the group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carbonamido group, a sulfamoyl group, and a sulfonamide group 1,2,4-triazo having an alkyl or aryl group substituted with at least one substituted group A polishing composition comprising a heteroaromatic ring compound which is a diol derivative .

  According to the present invention, it is possible to provide a polishing composition having excellent polishing performance and a long shelf life.

[Polishing composition]
The polishing composition of the present invention is colloidal silica obtained by hydrolyzing alkoxysilane, and colloidal silica in which part of the surface is covered with aluminum atoms, and 2-methyl-4-isothiazoline. A compound having at least one isothiazolin-3-one skeleton selected from -3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, glycine, and a specific heteroaromatic compound described later , And may contain other compounds as necessary. The polishing composition of the present invention usually takes the form of a slurry in which the colloidal silica (abrasive grains) is dispersed in an aqueous solution in which each component is dissolved.
The polishing composition of the present invention is useful as a polishing composition used for chemical mechanical polishing of an object to be polished in the production of semiconductor devices.

  Moreover, as a preferable aspect of the polishing liquid for this invention, it is that pH is 2-8, More preferably, pH is 3.8-8.0.

  Each component constituting the metal polishing liquid will be described in detail below, but each component may be used alone or in combination of two or more.

  In the present invention, the “polishing composition” is not limited to the aspect of the composition (concentration) used for polishing, but the aspect to be diluted as necessary during use is also used unless otherwise specified in the present invention. Called. When the concentrated liquid is used for polishing, it is diluted with water or an aqueous solution and used for polishing, and the dilution ratio is generally 1 to 20 times by volume.

<(A) Colloidal silica obtained by hydrolysis of alkoxysilane, and a part of the surface thereof is covered with aluminum atoms>
The polishing composition of the present invention is colloidal silica obtained by hydrolyzing alkoxysilane as at least a part of abrasive grains , and a part of the surface of the colloidal silica is covered with aluminum atoms ( hereinafter, containing occasionally referred to as "specific colloidal silica".). The specific colloidal silica functions as an abrasive grain in the polishing composition of the present invention.

  In the present invention, “a colloidal silica whose surface is partially covered with aluminum” means a state in which aluminum atoms are present on the surface of colloidal silica having a site containing a silicon atom having a coordination number of 4. A colloidal silica surface may be bonded to an aluminum atom coordinated with four oxygen atoms to form a new surface in which the aluminum atom is fixed in a four-coordinate state, and It may be in a state in which silicon atoms existing on the surface are once extracted and a new surface is formed in which aluminum atoms are replaced.

The colloidal silica used in the preparation of the specific colloidal silica, containing no impurities such as alkali metal inside the particles, Ru colloidal silica der obtained by hydrolysis of alkoxysilane. On the other hand, in the case of colloidal silica mosquitoes prepared by the method of removing alkali from the alkali silicate aqueous solution, since the alkali metal remaining inside the particles gradually eluted, there is influence concern polishing performance, such viewpoints pressurized et al, those obtained by hydrolysis of the alkoxysilane used as a raw material.
The particle size of the colloidal silica used as a raw material is appropriately selected according to the purpose of use of the abrasive grains, but is generally about 10 to 200 nm.

As a method for obtaining a specific colloidal silica by replacing silicon atoms on the surface of such colloidal silica particles with an aluminum atom, for example, a method of adding an aluminate compound such as sodium aluminate to a dispersion of colloidal silica is preferably used. be able to. These methods are described in detail in Japanese Patent No. 3463328 and Japanese Patent Laid-Open No. 63-123807, and this description can be applied to the present invention.
As another method, a method of adding aluminum alkoxide to a dispersion of colloidal silica can be mentioned.

  In particular colloidal silica, the aluminosilicate site generated by the reaction of tetracoordinate aluminate ion and the silanol group on the surface of colloidal silica fixes negative charge and gives large negative zeta potential to the particles. Is also excellent in dispersibility. Therefore, it is important that the specific colloidal silica produced by the method as described above exists in a state where an aluminum atom is coordinated to four oxygen atoms.

  Such a structure, that is, the occurrence of substitution of silicon atoms and aluminum atoms on the colloidal silica surface can be easily confirmed, for example, by measuring the zeta potential of the abrasive grains.

The amount of substitution of silicon atoms on the surface of colloidal silica with aluminum atoms is such that the surface atom substitution rate (number of introduced aluminum atoms / number of surface silicon atom sites) of colloidal silica is preferably 0.001% or more and 20% or less, and more preferably. Is from 0.01% to 10%, particularly preferably from 0.1% to 5%.
When the silicon atom on the surface of the colloidal silica is replaced with an aluminum atom, the substitution amount with the aluminum atom is controlled by controlling the addition amount (concentration) of an aluminate compound, aluminum alkoxide, etc. added to the colloidal silica dispersion. It can be appropriately controlled.

Here, the amount of aluminum atoms introduced into the colloidal silica surface (number of introduced aluminum atoms / number of surface silicon atom sites) is consumed from the unreacted aluminum compound remaining after the reaction among the aluminum compounds added to the dispersion. The amount of the obtained aluminum compound was calculated, assuming that they reacted 100%, the surface area converted from the colloidal silica diameter, the specific gravity of colloidal silica 2.2, and the number of silanol groups per unit surface area (5-8 pieces / nm ²⁾ it can be estimated from actual measurements obtained specific colloidal silica per se and elemental analysis, aluminum is not present inside the particles, assuming spread uniformly and thinly on the surface, the colloidal silica The surface area / specific gravity and the number of silanol groups per unit surface area are obtained.

As a specific production method, for example, colloidal silica is dispersed in water in the range of 1 to 50% by mass, a pH adjuster is added to the dispersion to adjust the pH to 7 to 11, and then at around room temperature, Add aqueous ammonium aluminate and stir at that temperature for 1-10 hours. Then, the method of removing an impurity by ion exchange, ultrafiltration, etc., and obtaining specific colloidal silica is mentioned.
The size (volume equivalent diameter) of the specific colloidal silica obtained is preferably 3 m to 200 nm, more preferably 5 nm to 100 nm, and particularly preferably 10 nm to 60 nm. In addition, the value measured by the dynamic light scattering method is employ | adopted for the particle size (volume equivalent diameter) of specific colloidal silica.

Among the abrasive grains contained in the polishing composition of the present invention, the mass ratio of the specific colloidal silica is preferably 50% or more, and particularly preferably 80% or more. All of the contained abrasive grains may be a specific colloidal silica.
The content of the specific colloidal silica in the polishing liquid when using the polishing composition is preferably 0.001% by mass to 5% by mass, and more preferably 0.01% by mass to 0.5% by mass. Yes, particularly preferably 0.05% by mass or more and 0.2% by mass or less.

In addition to the specific colloidal silica, the polishing composition of the present invention can contain abrasive grains other than the specific colloidal silica as long as the effects of the present invention are not impaired. As the abrasive grains that can be used here, fumed silica, colloidal silica, ceria, alumina, titania and the like are preferable, and colloidal silica is particularly preferable.
The size of the abrasive grains other than colloidal silica in which at least a part of silicon atoms on the surface are replaced with aluminum atoms is preferably equal to or more than twice that of the specific colloidal silica.

  The polishing composition of the present invention may contain abrasive grains other than the specific colloidal silica. Among all the abrasive grains contained in the metal polishing slurry, the content of the specific colloidal silica is preferably 50% by mass or more, and particularly preferably 80% by mass or more.

  In the polishing composition of the present invention, fumed silica, colloidal silica, ceria, alumina, titania and the like are preferable, and colloidal silica is particularly preferable. These sizes are preferably equal to or more than that of the specific colloidal silica, and are preferably twice or less.

<(B) Compound having isothiazoline-3-one skeleton>
The polishing composition of the present invention contains at least one compound having an isothiazolin-3-one skeleton as an essential component as the component (b). Two or more kinds of compounds having an isothiazolin-3-one skeleton may be mixed and used.

  As the compound having an isothiazolin-3-one skeleton in the present invention, a compound containing no halogen is more preferable. Further, it may be dissolved in water using a solvent.

Specific examples of the compound having the isothiazolin-3-one skeleton include 2-methyl-4-isothiazolin-3-one (abbreviation: MIT), 5-chloro-2-methyl-4-isothiazolin-3-one (abbreviation). : CIT), 2-n-octyl-4-isothiazolin-3-one (OIT), Nn-butyl-1,2-benzisothiazolin-3-one 1,2-benzisothiazolin-3-one, 4- Preferred examples include chloro-2methyl-isothiazolin-3-one and the like. In the present invention, from 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one It is necessary to contain at least one selected .

  Moreover, a commercial item can also be used as a compound which has an isothiazolin-3-one frame | skeleton, for example, ACTICIDE by Thor, Rocima by Rohm & Haas, ZONEN by Chemicrea, etc. are mentioned.

  The content of the compound having an isothiazolin-3-one skeleton in the polishing composition of the present invention is 1 to 500 from 1 L of the polishing composition from the viewpoint of coexistence of polishing performance such as polishing speed and dishing and shelf life. It is preferable that it is, it is more preferable that it is 5-100, and it is especially preferable that it is 10-50.

  The polishing composition of the present invention may contain an optional component as necessary in addition to the above-described essential components. Hereinafter, optional components applicable to the polishing composition of the present invention will be described.

<(C) Surfactant and / or hydrophilic polymer>
The polishing composition of the present invention preferably contains (c) a surfactant and / or a hydrophilic polymer.
As the surfactant and / or the hydrophilic polymer, an acid form is desirable, and in the case of taking a salt structure, ammonium salt, potassium salt, sodium salt and the like can be mentioned, and ammonium salt and potassium salt are particularly preferable.

  Both the surfactant and the hydrophilic polymer have the action of reducing the contact angle to the surface to be polished and the action of promoting uniform polishing. As the surfactant and / or hydrophilic polymer to be used, those selected from the following group are suitable.

  Examples of the anionic surfactant include carboxylate, sulfonate, sulfate ester salt and phosphate ester salt. As the carboxylate salt, soap, N-acyl amino acid salt, polyoxyethylene or polyoxypropylene alkyl ether carboxyl Acid salt, acylated peptide; as sulfonate, alkyl sulfonate, alkyl benzene and alkyl naphthalene sulfonate, naphthalene sulfonate, sulfosuccinate, α-olefin sulfonate, N-acyl sulfonate; sulfate ester Salts include sulfated oil, alkyl sulfates, alkyl ether sulfates, polyoxyethylene or polyoxypropylene alkyl allyl ether sulfates, alkyl amide sulfates; phosphate ester salts such as alkyl phosphates, polyoxyethylene or polyoxy B pyrene alkyl allyl ether phosphate can be exemplified.

As cationic surfactant, aliphatic amine salt, aliphatic quaternary ammonium salt, benzalkonium chloride salt, benzethonium chloride, pyridinium salt, imidazolinium salt; as amphoteric surfactant, carboxybetaine type, sulfobetaine type, Mention may be made of aminocarboxylates, imidazolinium betaines, lecithins, alkylamine oxides.
Nonionic surfactants include ether type, ether ester type, ester type and nitrogen-containing type. Ether type includes polyoxyethylene alkyl and alkylphenyl ether, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene poly Examples include oxypropylene block polymer, polyoxyethylene polyoxypropylene alkyl ether, ether ester type, glycerin ester polyoxyethylene ether, sorbitan ester polyoxyethylene ether, sorbitol ester polyoxyethylene ether, ester type, Polyethylene glycol fatty acid ester, glycerin ester, polyglycerin ester, sorbitan ester, propylene glycol ester Le, sucrose esters, nitrogen-containing type, fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkyl amide, and the like.
In addition, fluorine surfactants, silicone surfactants, and the like can be given.

  Polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol alkyl ether, polyethylene glycol alkenyl ether, alkyl polyethylene glycol, alkyl polyethylene glycol alkyl ether, alkyl polyethylene glycol alkenyl ether, alkenyl polyethylene glycol, alkenyl polyethylene glycol alkyl ether, alkenyl polyethylene glycol Alkenyl ether, polypropylene glycol alkyl ether, polypropylene glycol alkenyl ether, alkyl polypropylene glycol, alkyl polypropylene glycol alkyl ether, alkyl polypropylene glycol alkenyl ether, alkenyl poly Ethers such as pyrene glycol, alkenyl polypropylene glycol alkyl ether and alkenyl polypropylene glycol alkenyl ether; polysaccharides such as alginic acid, pectinic acid, carboxymethylcellulose, curdlan and pullulan; amino acid salts such as glycine ammonium salt and glycine sodium salt; polyaspartic acid , Polyglutamic acid, polylysine, polymalic acid, polymethacrylic acid, polymethacrylic acid ammonium salt, polymethacrylic acid sodium salt, polymaleic acid, polyitaconic acid, polyfumaric acid, poly (p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, Amino polyacrylamide, polyacrylic acid ammonium salt, polyacrylic acid sodium salt, polyamic acid, polyamic acid ammonia Salts, polycarboxylic acids and salts thereof, such as polyamic acid sodium salt and polyglyoxylic acid; polyvinyl alcohol, vinyl polymers such as polyvinyl pyrrolidone and acrolein and the like.

  However, when the substrate to be applied is a silicon substrate for a semiconductor integrated circuit or the like, contamination by alkali metal, alkaline earth metal, halide, etc. is not desirable, so an acid type is desirable. desirable. This is not the case when the substrate is a glass substrate or the like. Among the above exemplified compounds, polyacrylic acid ammonium salt, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, and polyoxyethylene polyoxypropylene block polymer are more preferable.

The total amount of the surfactant and / or hydrophilic polymer added is preferably 0.001 to 10 g, and preferably 0.01 to 5 g in 1 L of the polishing composition when used for polishing. More preferably, it is 0.02 to 3 g. That is, the addition amount of the surfactant and / or the hydrophilic polymer is preferably 0.001 g or more for obtaining a sufficient effect, and is preferably 10 g or less from the viewpoint of preventing the CMP rate from being lowered. Moreover, as a weight average molecular weight of these surfactant and / or hydrophilic polymer, 500-100000 are preferable, and 2000-50000 are especially preferable.
Only one type of surfactant may be used, two or more types may be used, and different types of surfactants may be used in combination.

<(D) Compound having at least one carboxyl group and at least one amino group in the molecule>
The polishing composition of the present invention preferably contains (d) a compound having at least one carboxyl group and at least one amino group in the molecule. More preferably, at least one of the amino groups of the compound is a secondary or tertiary amino group. The compound may further have a substituent.

The compound having at least one carboxyl group and at least one amino group in the molecule that can be used in the present invention is preferably an amino acid or an aminopolyacid, and more preferably one selected from the following group: Among them, in the present invention, it is necessary to contain glycine .

  As amino acids, glycine, hydroxyethyl glycine, dihydroxyethyl glycine, glycyl glycine, N-methyl glycine, L-alanine, β-alanine, L-2-aminobutyric acid, L-norvaline, L-valine, L-leucine, L-norleucine, L-isoleucine, L-alloisoleucine, L-phenylalanine, L-proline, sarcosine, L-ornithine, L-lysine, taurine, L-serine, L-threonine, L-allothreonine, L-homoserine, L-tyrosine, 3,5-diiodo-L-tyrosine, β- (3,4-dihydroxyphenyl) -L-alanine, L-thyroxine, 4-hydroxy-L-proline, L-cystine, L-methionine, L -Ethionine, L-Lanthionine, L-cystathionine, L-cystine, L-cystine Stinic acid, L-aspartic acid, L-glutamic acid, S- (carboxymethyl) -L-cysteine, 4-aminobutyric acid, L-asparagine, L-glutamine, azaserine, L-arginine, L-canavanine, L-citrulline, δ-hydroxy-L-lysine, creatine, L-kynurenine, L-histidine, 1-methyl-L-histidine, 3-methyl-L-histidine, ergothioneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin Amino acids such as II and antipine. Among these, glycine, L-alanine, L-histidine, L-proline, L-lysine, and dihydroxyethylglycine are preferable.

  Examples of aminopolyacids include iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, nitrilotrismethylenephosphonic acid, ethylenediamine-N, N, N ′, N′-tetramethylene. Sulfonic acid, transcyclohexanediaminetetraacetic acid, 1,2-diaminopropanetetraacetic acid, glycol etherdiaminetetraacetic acid, ethylenediamine orthohydroxyphenylacetic acid, ethylenediamine disuccinic acid (SS form), N- (2-carboxylate ethyl) -L -Aspartic acid, β-alanine diacetate, N, N′-bis (2-hydroxybenzyl) ethylenediamine-N, N′-diacetic acid, and the like.

The amino acids or amino poly acid can be used in the present invention may be a compound represented by the following following formula (1) or (2).

R ¹ in the general formula (1) represents a single bond, an alkylene group, or a phenylene group. R ² and R ³ in the general formula (1) each independently represent a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, or an aryl group. R ⁴ and R ⁵ in the general formula (1) each independently represent a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group, or an acyl group.
However, when R ¹ is a single bond, at least one of R ⁴ and R ⁵ is not a hydrogen atom.

The alkylene group as R ¹ in the general formula (1) may be linear, branched or cyclic, and preferably has 1 to 8 carbon atoms, and examples thereof include a methylene group and an ethylene group. Can do.
Examples of the substituent that the alkylene group may have include a hydroxyl group and a halogen atom.

The alkyl group as R ² and R ³ in the general formula (1) preferably has 1 to 8 carbon atoms, and examples thereof include a methyl group and a propyl group.
The cycloalkyl group as R ² and R ³ in the general formula (1) preferably has 5 to 15 carbon atoms, and examples thereof include a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.
The alkenyl group as R ² and R ³ in the general formula (1) preferably has 2 to 9 carbon atoms, and examples thereof include a vinyl group, a propenyl group, and an allyl group.
The alkynyl group as R ² and R ³ in the general formula (1) preferably has 2 to 9 carbon atoms, and examples thereof include an ethynyl group, a propynyl group, and a butynyl group.

The aryl group as R ² and R ³ in the general formula (1) preferably has 6 to 15 carbon atoms, and examples thereof include a phenyl group.
The alkylene chain in these groups may have a hetero atom such as an oxygen atom or a sulfur atom.
Examples of the substituent that each group represented by R ² and R ³ in the general formula (1) may have include a hydroxyl group, a halogen atom, an aromatic ring (preferably having 3 to 15 carbon atoms), a carboxyl group, and an amino group. Can be mentioned.

The alkyl group as R ⁴ and R ⁵ in the general formula (1) preferably has 1 to 8 carbon atoms, and examples thereof include a methyl group and an ethyl group.
The acyl group preferably has 2 to 9 carbon atoms, and examples thereof include a methylcarbonyl group.
Examples of the substituent that each group represented by R ⁴ and R ⁵ in the general formula (1) may have include a hydroxyl group, an amino group, and a halogen atom.

In general formula (1), it is preferable that either one of R ⁴ and R ⁵ is not a hydrogen atom. In the general formula (1), it is particularly preferable that R ¹ is a single bond, and R ² and R ⁴ are hydrogen atoms. In this case, R ³ represents a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, or an aryl group, and particularly preferably a hydrogen atom or an alkyl group. R ⁵ represents a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group, or an acyl group, and an alkyl group is particularly preferable. As the substituent that the alkyl group as R ³ may have, a hydroxyl group, a carboxyl group, or an amino group is preferable. As the substituent that the alkyl group as R ⁵ may have, a hydroxyl group or an amino group is preferable.

R ⁶ in the general formula (2) represents a single bond, an alkylene group, or a phenylene group. R ⁷ and R ⁸ in the general formula (2) each independently represent a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, or an aryl group. R ⁹ in the general formula (2) represents a hydrogen atom, a halogen atom, a carboxyl group, or an alkyl group. R ¹⁰ in the general formula (2) represents an alkylene group. However, when R ¹⁰ is —CH ₂ —, R ⁶ is not a single bond, or at least R ⁹ is not a hydrogen atom.

The alkylene group as R ⁶ and R ¹⁰ in the general formula (2) may be linear, branched or cyclic, and preferably has 1 to 8 carbon atoms, such as a methylene group or an ethylene group. Can be mentioned.
Examples of the substituent that the alkylene group and phenylene group may have include a hydroxyl group and a halogen atom.

The alkyl group as R ⁷ and R ⁸ in the general formula (2) preferably has 1 to 8 carbon atoms, and examples thereof include a methyl group and a propyl group.
The cycloalkyl group as R ⁷ and R ⁸ in the general formula (2) preferably has 5 to 15 carbon atoms, and examples thereof include a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.
The alkenyl group as R ⁷ and R ⁸ in the general formula (2) preferably has 2 to 9 carbon atoms, and examples thereof include a vinyl group, a propenyl group, and an allyl group.
The alkynyl group as R ⁷ and R ⁸ in the general formula (2) preferably has 2 to 9 carbon atoms, and examples thereof include an ethynyl group, a propynyl group, and a butynyl group.

The aryl group as R ⁷ and R ⁸ in the general formula (2) preferably has 6 to 15 carbon atoms, and examples thereof include a phenyl group.
The alkylene chain in these groups may have a hetero atom such as an oxygen atom or a sulfur atom.
Examples of the substituent that each group represented by R ⁷ and R ⁸ in the general formula (2) may have include a hydroxyl group, a halogen atom, and an aromatic ring (preferably having 3 to 15 carbon atoms).

The alkyl group as R ⁹ in the general formula (2) preferably has 1 to 8 carbon atoms, and examples thereof include a methyl group and an ethyl group.
The acyl group as R ⁹ in the general formula (2) preferably has 2 to 9 carbon atoms, and examples thereof include a methylcarbonyl group.
The alkylene chain in these groups may have a hetero atom such as an oxygen atom or a sulfur atom.
Examples of the substituent that each group as R ⁹ in the general formula (2) may have include a hydroxyl group, an amino group, a halogen atom, and a carboxyl group.
In the general formula (2), R ⁹ is preferably not a hydrogen atom.

  Although the preferable specific example of a compound represented by General formula (1) or General formula (2) below is given, it does not limit to these.

  There is no restriction | limiting in particular as a synthesis method of the compound represented by General formula (1) or (2), It can synthesize | combine by a well-known method. Moreover, a commercially available compound may be used as the compound represented by the general formula (1) or (2).

  The polishing composition of the present invention further preferably contains two or more compounds having at least one carboxyl group and at least one amino group in the molecule. Among these compounds, one carboxyl group is present in the molecule. It is particularly preferable to use a compound having only 2 and a compound having 2 or more carboxyl groups in the molecule.

As the addition amount of the compound having at least one carboxyl group and at least one amino group in the molecule in the polishing composition of the present invention,
From the standpoint of achieving both polishing speed and flatness, it is preferably 0.1% by mass or more and 5% by mass or less, more preferably 0.5% by mass or more and 2% by mass or less.

<(E) Heteroaromatic ring compound>
The polishing composition of the present invention, it contains (e) a heterocyclic aromatic ring compound.

The heteroaromatic ring compound in the present invention includes a specific heteroaromatic ring compound which is a tetrazole derivative, a 1,2,3-triazole derivative, or a 1,2,4-triazole derivative as described below .

(Tetrazole derivatives)
On a nitrogen atom forming a tetrazole ring having no substituent, one 且, select the 5-position of the tetrazole, sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group, and from the group consisting of a sulfonamide group Or an alkyl group substituted with at least one substituent selected from the group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carbonamido group, a sulfamoyl group, and a sulfonamido group A tetrazole derivative characterized by comprising:

(1,2,3-triazole derivative)
Do not have a substituent on a nitrogen atom forming a 1,2,3-triazole ring, one 且, the 4-position and / or 5-position of 1,2,3-triazole, a hydroxy group, a carboxy group, a sulfo group , A substituent selected from the group consisting of an amino group, a carbamoyl group, a carbonamido group, a sulfamoyl group, and a sulfonamido group, or a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carbonamido group, and a sulfamoyl group And a 1,2,3-triazole derivative having an alkyl group or an aryl group substituted with at least one substituent selected from the group consisting of sulfonamide groups.

(1,2,4-triazole derivative)
Do not have a substituent on a nitrogen atom forming a 1,2,4-triazole ring, one 且, in the 2-position and / or 5-position of 1,2,4-triazole, a sulfo group, a carbamoyl group, a carbonamide A substituent selected from the group consisting of a group, a sulfamoyl group, and a sulfonamide group, or a group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carbonamido group, a sulfamoyl group, and a sulfonamide group A 1,2,4-triazole derivative having an alkyl group or an aryl group substituted with at least one selected substituent.

Specific examples of the heteroaromatic ring compound in the present invention include the following exemplary compounds (I- 6 ) to (I-16), but are not limited thereto.

  The addition amount of the heteroaromatic ring compound in the polishing composition of the present invention is preferably 0.0001% by mass or more and 0.005% by mass or less, more preferably 0.001% by mass or less with respect to 1 kg of the polishing composition. It is 0005 mass% or more and 0.002 mass% or less.

<(F) Compound having at least one amino group and at least one sulfo group in the molecule>
The polishing composition of the present invention preferably contains (f) a compound having at least one amino group and at least one sulfo group in the molecule. Examples of the compound include aminomethanesulfonic acid and taurine, and taurine is preferable.

  The addition amount of the compound having at least one amino group and at least one sulfo group in the molecule in the polishing composition of the present invention is preferably 0.1% by mass or more and 10% by mass or less with respect to 1 kg of the polishing composition. 1 mass% or more and 5 mass% or less are still more preferable.

<(G) Phosphate or phosphite>
The polishing composition of the present invention preferably contains (g) a phosphate or a phosphite when it contains an inorganic component other than abrasive grains.

In the polishing composition of the present invention, due to the reactivity and adsorptivity to the polishing surface, the solubility of the polishing metal, the electrochemical properties of the surface to be polished, the dissociation state of the compound functional group, the stability as a liquid, etc. It is preferable to appropriately set the kind of component, the amount added, or the pH.
As described above, the polishing composition of the present invention preferably has a pH of 2 to 8, more preferably a pH of 3.8 to 8.

<(H) Oxidizing agent>
The polishing composition of the present invention preferably contains a compound (oxidant) that can oxidize a metal that is a suitable polishing target.
Examples of the oxidizing agent include hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, Bichromate, permanganate, ozone water and silver (II) salt, iron (III) salt are mentioned.
Examples of iron (III) salts include inorganic iron (III) salts such as iron nitrate (III), iron chloride (III), iron sulfate (III), iron bromide (III), and organic iron (III) salts. Complex salts are preferably used.

  When an organic complex salt of iron (III) is used, examples of complex-forming compounds constituting the iron (III) complex salt include acetic acid, citric acid, oxalic acid, salicylic acid, diethyldithiocarbamic acid, succinic acid, tartaric acid, glycolic acid, glycine , Alanine, aspartic acid, thioglycolic acid, ethylenediamine, trimethylenediamine, diethylene glycol, triethylene glycol, 1,2-ethanedithiol, malonic acid, glutaric acid, 3-hydroxybutyric acid, propionic acid, phthalic acid, isophthalic acid, 3 Aminopolycarboxylic acid and its salt are mentioned other than -hydroxy salicylic acid, 3,5-dihydroxy salicylic acid, gallic acid, benzoic acid, maleic acid, etc. and these salts.

  Examples of aminopolycarboxylic acids and salts thereof include ethylenediamine-N, N, N ′, N′-tetraacetic acid, diethylenetriaminepentaacetic acid, 1,3-diaminopropane-N, N, N ′, N′-tetraacetic acid, , 2-Diaminopropane-N, N, N ′, N′-tetraacetic acid, ethylenediamine-N, N′-disuccinic acid (racemic), ethylenediamine disuccinic acid (SS), N- (2-carboxylate ethyl) ) -L-aspartic acid, N- (carboxymethyl) -L-aspartic acid, β-alanine diacetic acid, methyliminodiacetic acid, nitrilotriacetic acid, cyclohexanediaminetetraacetic acid, iminodiacetic acid, glycol etherdiaminetetraacetic acid, ethylenediamine 1-N, N'-diacetic acid, ethylenediamine orthohydroxyphenylacetic acid, N, N-bis (2-hydroxybenzyl) ethylenedi Min -N, include and salts thereof such as N- diacetic acid. The kind of the counter salt is preferably an alkali metal salt or an ammonium salt, and particularly preferably an ammonium salt.

Among them, hydrogen peroxide, iodate, hypochlorite, chlorate, persulfate, and an organic complex salt of iron (III) are preferable, and a preferable complex-forming compound when an organic complex salt of iron (III) is used is Citric acid, tartaric acid, aminopolycarboxylic acid (specifically, ethylenediamine-N, N, N ′, N′-tetraacetic acid, diethylenetriaminepentaacetic acid, 1,3-diaminopropane-N, N, N ′, N '-Tetraacetic acid, ethylenediamine-N, N'-disuccinic acid (racemic), ethylenediaminedisuccinic acid (SS), N- (2-carboxylateethyl) -L-aspartic acid, N- (carboxymethyl)- L-aspartic acid, β-alanine diacetic acid, methyliminodiacetic acid, nitrilotriacetic acid, iminodiacetic acid).
Among the oxidizing agents, hydrogen peroxide, persulfate, and iron (III) ethylenediamine-N, N, N ′, N′-tetraacetic acid, 1,3-diaminopropane-N, N, N ′, N′— Most preferred is a complex of tetraacetic acid and ethylenediamine disuccinic acid (SS form).

  The addition amount of the oxidizing agent is preferably 0.003 mol to 8 mol, more preferably 0.03 mol to 6 mol, more preferably 0.1 mol to 4 mol, per liter of the polishing composition when used for polishing. It is particularly preferable to do this. That is, the addition amount of the oxidizing agent is preferably 0.003 mol or more from the viewpoint of sufficient metal oxidation and ensuring a high CMP rate, and is preferably 8 mol or less from the viewpoint of preventing roughening of the polished surface.

[Raw metal materials]
In the present invention, the semiconductor to be polished is preferably an LSI having wiring made of copper metal and / or copper alloy, and particularly preferably a copper alloy. Furthermore, the copper alloy containing silver is preferable among copper alloys. The silver content contained in the copper alloy is preferably 40% by mass or less, particularly 10% by mass or less, more preferably 1% by mass or less, and most preferably in the range of 0.00001 to 0.1% by mass. Exhibits excellent effects.

[Thickness of wiring]
In the present invention, the semiconductor to be polished is, for example, a DRAM device system having a half pitch of 0.15 μm or less, particularly 0.10 μm or less, more preferably 0.08 μm or less, while MPU device system is 0.12 μm or less. In particular, an LSI having a wiring of 0.09 μm or less, more preferably 0.07 μm or less is preferable. The polishing liquid of the present invention exhibits particularly excellent effects on these LSIs.

[Barrier metal]
In the present invention, it is preferable to provide a barrier layer for preventing the diffusion of copper between the wiring in which the semiconductor is made of copper metal and / or a copper alloy and the interlayer insulating film. As the barrier layer, a low-resistance metal material is preferable, and TiN, TiW, Ta, TaN, W, WN, and Ru are particularly preferable, and Ta and TaN are particularly preferable.

[Polishing method]
The polishing composition of the present invention is a concentrated liquid, and when used, it is diluted with water to make a working liquid, or each component is mixed in the form of an aqueous solution described in the next section, and if necessary, In some cases, it is diluted with water to make a working solution, or it may be prepared as a working solution. The polishing method using the polishing composition of the present invention can be applied to any case, and the polishing liquid is supplied to the polishing pad on the polishing surface plate and brought into contact with the surface to be polished to thereby connect the surface to be polished and the polishing pad. This is a polishing method in which polishing is performed by relative movement.
As an apparatus for polishing, there is a general polishing apparatus having a polishing surface plate with a holder for holding a semiconductor substrate having a surface to be polished and a polishing pad attached (a motor etc. capable of changing the number of rotations is attached). Can be used. As the polishing pad, a general nonwoven fabric, foamed polyurethane, porous fluororesin, or the like can be used, and there is no particular limitation. The polishing conditions are not limited, but the rotation speed of the polishing surface plate is preferably a low rotation of 200 rpm or less so that the substrate does not jump out. The pressure applied to the polishing pad of the semiconductor substrate having the surface to be polished (film to be polished) is preferably ⁵ to 500 g / cm ² in order to satisfy the uniformity of the polishing rate within the wafer surface and the flatness of the pattern. Is more preferably 12 to 240 g / cm ² .

  During polishing, the polishing composition is continuously supplied to the polishing pad with a pump or the like. Although there is no restriction | limiting in this supply amount, it is preferable that the surface of a polishing pad is always covered with polishing liquid. The semiconductor substrate after polishing is thoroughly washed in running water, and then dried after removing water droplets adhering to the semiconductor substrate using a spin dryer or the like. In the polishing method of the present invention, the aqueous solution to be diluted is the same as the aqueous solution described below. The aqueous solution is water containing at least one of an oxidizing agent, an acid, an additive, and a surfactant in advance, and a component obtained by adding up the components contained in the aqueous solution and the components of the polishing composition to be diluted is polished. It becomes a component at the time of grind | polishing using the composition for water. When diluted with an aqueous solution and used, components that are difficult to dissolve can be blended in the form of an aqueous solution, and a more concentrated polishing composition can be prepared.

  As a method of diluting the concentrated polishing composition by adding water or an aqueous solution, the pipe for supplying the concentrated polishing composition and the pipe for supplying the water or the aqueous solution are joined together and mixed, mixed and diluted. There is a method of supplying the polished polishing composition to the polishing pad. Mixing is a method in which liquids collide with each other through a narrow passage under pressure, a method in which a filling such as a glass tube is filled in the pipe, and the flow of liquid is repeatedly separated and merged. Conventional methods such as a method of providing blades that rotate in the above can be employed.

  The supply rate of the polishing composition is preferably 10 to 1000 ml / min, and more preferably 170 to 800 ml / min in order to satisfy the uniformity of the polishing rate within the wafer surface and the flatness of the pattern.

  As a method of diluting and polishing the concentrated polishing composition with water or an aqueous solution, a pipe for supplying the polishing composition and a pipe for supplying water or an aqueous solution are provided independently, and a predetermined amount of liquid is supplied from each. This is a method of polishing while supplying to the polishing pad and mixing by the relative movement of the polishing pad and the surface to be polished. Alternatively, there is a method in which a predetermined amount of a concentrated polishing composition and water or an aqueous solution are mixed in one container, and then the mixed polishing composition is supplied to a polishing pad for polishing.

According to another polishing method of the present invention, a component to be contained in a polishing composition is divided into at least two components, and when these components are used, a water or aqueous solution is added to dilute the polishing pad on a polishing platen. The surface to be polished is brought into contact with the surface to be polished, and the surface to be polished and the polishing pad are moved relative to each other for polishing.
For example, an oxidizing agent is one component (A), an acid, an additive, a surfactant, and water are one component (B), and when they are used, the component (A) The component (B) is diluted before use.
In addition, the low-solubility additive is divided into two components (A) and (B), and the oxidizing agent, additive and surfactant are one component (A), and the acid, additive, surfactant and Water is used as one component (B), and when these are used, water or an aqueous solution is added to dilute the component (A) and the component (B). In the case of this example, three pipes for supplying the component (A), the component (B), and water or an aqueous solution are required, and dilution mixing is performed on one pipe that supplies the three pads to the polishing pad. There is a method of combining and mixing in the pipe. In this case, it is also possible to combine two pipes and then connect another pipe.

  For example, it is a method in which a component containing an additive that is difficult to dissolve is mixed with another component, a mixing path is lengthened to ensure a dissolution time, and then a pipe for water or an aqueous solution is further combined. Other mixing methods are as described above, in which the three pipes are each guided directly to the polishing pad and mixed by the relative movement of the polishing pad and the surface to be polished, and the three components are mixed in one container. The diluted polishing composition is supplied to the polishing pad. In the above polishing method, one constituent component containing an oxidizing agent is made 40 ° C. or lower, the other constituent components are heated in the range of room temperature to 100 ° C., and one constituent component and another constituent component or water or an aqueous solution When the mixture is diluted and used, it can be adjusted to 40 ° C. or lower after mixing. Since solubility becomes high when temperature is high, it is a preferable method for increasing the solubility of raw materials with low solubility of the polishing composition.

  A raw material in which other components not containing an oxidizing agent are heated and dissolved in the range of room temperature to 100 ° C. is precipitated in the solution when the temperature is lowered. It is necessary to dissolve what is deposited by heating. For this, a means for feeding a heated component solution and a means for stirring the liquid containing the precipitate, feeding the liquid, and heating and dissolving the pipe can be employed. When the temperature of one component containing an oxidant is increased to 40 ° C. or higher, the oxidant may be decomposed. Therefore, the heated component and the oxidation for cooling the heated component When mixed with one component containing an agent, the temperature is set to 40 ° C. or lower.

  In the present invention, as described above, the components of the polishing composition may be divided into two or more parts and supplied to the polishing surface. In this case, it is preferable to divide and supply the component containing an oxide and the component containing an acid. Further, the polishing composition may be used as a concentrated liquid and supplied to the polishing surface separately from the dilution water.

〔pad〕
The polishing pad may be a non-foamed structure pad or a foamed structure pad. The former uses a hard synthetic resin bulk material like a plastic plate for a pad. Further, the latter further includes three types of a closed foam (dry foam system), a continuous foam (wet foam system), and a two-layer composite (laminated system), and a two-layer composite (laminated system) is particularly preferable. Foaming may be uniform or non-uniform.
Further, it may contain abrasive grains (for example, ceria, silica, alumina, resin, etc.) used for polishing. In addition, the hardness may be either soft or hard, and either may be used. In the laminated system, it is preferable to use a different hardness for each layer. The material is preferably non-woven fabric, artificial leather, polyamide, polyurethane, polyester, polycarbonate or the like. In addition, the surface contacting the polishing surface may be subjected to processing such as lattice grooves / holes / concentric grooves / helical grooves.

[Wafer]
The target wafer to be subjected to CMP with the polishing composition of the present invention preferably has a diameter of 200 mm or more, particularly preferably 300 mm or more. The effect of the present invention is remarkably exhibited when the thickness is 300 mm or more.

  Hereinafter, the present invention will be described by way of examples. The present invention is not limited to these examples.

[Preparation of specific colloidal silica (A-1)]
To 1000 g of a 20 mass% aqueous dispersion of colloidal silica (product name: Quatron PL-3, manufacturer: Fuso Chemical) obtained by hydrolyzing tetraethoxysilane and having an average abrasive grain size (average primary particle diameter) of 35 nm, Ammonia water is added to adjust the pH to 9.0, and then the aqueous solution of sodium aluminate having an Al ₂ O ₃ concentration of 3.6% by mass and a Na ₂ O / Al ₂ O ₃ molar ratio of 1.50 is stirred at room temperature. 15.9 g was slowly added within a few minutes and stirred for 0.5 hours. The obtained sol was placed in a SUS autoclave apparatus, heated at 130 ° C. for 4 hours, and then filled with a hydrogen-type strongly acidic cation exchange resin (Amberlite IR-120B), and a hydroxyl-type strongly basic anion exchange resin. A column packed with (Amberlite IRA-410) was passed through the column at a space velocity of 1 h ⁻¹ at room temperature, and the initial distillation was cut.
The volume average particle diameter of the specific colloidal silica (A-1) was 40 nm, and the aluminum coating amount determined by the above-described method was 1%. Moreover, the specific colloidal silica (A-1) did not show thickening or gelation after preparation.

[Preparation of polishing composition]
A polishing composition of Example 1 was prepared with the composition shown below using the specific colloidal silica (A-1) obtained as described above as abrasive grains. The pH of the composition was adjusted with ammonia and nitric acid.

Example 1
-Polishing composition-
・ Abrasive grains (specific colloidal silica (A-1)) 5 g / L
・ 2-methyl-4-isothiazolin-3-one (abbreviation: MIT) 0.05 g / L
・ Glycine (acid) 10g / L
Exemplified compound (I-8) (heteroaromatic ring compound) 0.05 g / L
・ Hydrogen peroxide 15g / L

(Example 2)
Example 1 is the same as Example 1 except that 5-chloro-2-methyl-4-isothiazolin-3-one (abbreviation: CIT) is added instead of 2-methyl-4-isothiazolin-3-one. Similarly, the polishing composition of Example 2 was prepared.

(Comparative Example 1)
In Example 1, instead of the specific colloidal silica (A-1), comparative colloidal silica (A-2) (product name: Quatron PL-3, manufactured by Fuso Chemical Industry Co., Ltd., average primary particle size 35 nm) was used. A polishing composition of Comparative Example 2 was prepared in the same manner as in Example 1 except that 2-methyl-4-isothiazolin-3-one was not used.

(Comparative Example 2)
In Example 1, instead of the specific colloidal silica (A-1), a comparative example was obtained in the same manner as in Example 1 except that the comparative colloidal silica (A-2) (average primary particle size: 35 nm) was used. 1 polishing composition was prepared.

(Comparative Example 3)
A polishing composition of Comparative Example 3 was prepared in the same manner as in Example 1 except that hydrogen peroxide was added instead of 2-methyl-4-isothiazolin-3-one in Example 1.

(Comparative Example 4)
A polishing composition of Comparative Example 4 was prepared in the same manner as in Example 1 except that benzimidazole was added instead of 2-methyl-4-isothiazolin-3-one in Example 1.

(Comparative Example 5)
A polishing composition of Comparative Example 5 was prepared in the same manner as in Example 1 except that phenoxyethanol was added instead of 2-methyl-4-isothiazolin-3-one in Example 1.

  After preparing the polishing composition (polishing liquid) prepared in Examples 1 and 2 and Comparative Examples 1 to 5 and storing it at room temperature for 6 months, polishing was performed by the following polishing method, and polishing performance (polishing speed, polishing rate, The number of occurrences of dishing and scratching was evaluated. Furthermore, the shelf life of each polishing composition was also evaluated. The evaluation results are shown in Table 3.

(A lapping master apparatus “LGP-612” was used as a polishing apparatus, and the film provided on each wafer was polished while supplying slurry under the following conditions, and the polishing rate at that time was calculated.
Substrate: Silicon wafer table with 8 inch copper film Rotation speed: 64 rpm
Head rotation speed: 65rpm
(Processing linear velocity = 1.0 m / s)
Polishing pressure: 140 hPa
Polishing pad: Product number IC-1400 (K-grv) + (A21) manufactured by Rohm and Haas
Slurry supply rate: 200 ml / min Measurement of polishing rate: Film pressure was converted from electric resistance before and after polishing. In particular,
Polishing rate (nm / min) = (thickness of copper film before polishing−thickness of copper film after polishing) / polishing time.

<Evaluation>
1. Polishing rate The polishing rate was calculated from the electrical resistance before and after polishing and converted into the film thickness by the following formula.
Polishing rate (nm / min) = (thickness of copper film before polishing−thickness of copper film after polishing) / polishing time

2. The dishing evaluation substrate is formed by patterning a silicon oxide film by a photolithography process and a reactive ion etching process to form wiring grooves and connection holes having a width of 0.09 to 100 μm and a depth of 600 nm, and a sputtering method. After forming a Ta film having a thickness of 20 nm by the sputtering method, a copper film having a thickness of 50 nm was formed by a sputtering method, and then a wafer on which a copper film having a total thickness of 1000 nm was formed by a plating method was cut into 6 × 6 cm.
The substrate is polished under the above conditions while supplying slurry onto the polishing cloth of the polishing surface plate of the polishing apparatus, and the step in the 100 μm / 100 μm Line / Space with 30% over polish is measured with a stylus type step measuring instrument. Was measured and dishing was determined.

3. Number of scratches The number of scratches was measured by counting the number of scratches per wafer using Surfscan SP1 manufactured by KLA-Tencor and SEM Vision manufactured by Applied Materials. The evaluation criteria are as follows.
-Evaluation criteria-
No scratch: Less than 50 scratches of 0.14 μm or more per wafer Scratch more: 50 scratches of 0.14 μm or more per wafer

4). Shelf life evaluation method The sedimentation / dispersion behavior of the particles in the polishing composition was measured from the transmitted / scattered light using a Turbiscan MA-2000 (manufactured by Eiko Seiki Co., Ltd.). The evaluation criteria are as follows.
-Evaluation criteria-
Evaluation was based on the attenuation rate of transmitted light intensity. If the decay rate after 6 months was 25% or more, the shelf life was determined to be 6 months or less.

  As shown in Table 3, it can be seen that the polishing compositions of Examples containing specific colloidal silica and a compound having an isothiazolin-3-one skeleton can achieve excellent polishing performance and a very long shelf life. .

Claims (2)

  Colloidal silica obtained by hydrolyzing alkoxysilane and having a part of its surface covered with aluminum atoms; 2-methyl-4-isothiazolin-3-one and 5-chloro- A compound having at least one isothiazolin-3-one skeleton selected from 2-methyl-4-isothiazolin-3-one, glycine, and a nitrogen atom forming a tetrazole ring, and having no substituent, and At the 5-position of tetrazole, a substituent selected from the group consisting of a sulfo group, an amino group, a carbamoyl group, a carbonamido group, a sulfamoyl group, and a sulfonamido group, or a hydroxy group, a carboxy group, a sulfo group, an amino group, and a carbamoyl group Selected from the group consisting of a group, a carbonamido group, a sulfamoyl group, and a sulfonamido group. Polishing composition and heteroaromatic ring compound is a tetrazole derivative, characterized by containing having at least one substituted alkyl group substituted with groups. Colloidal silica obtained by hydrolyzing alkoxysilane and having a part of its surface covered with aluminum atoms; 2-methyl-4-isothiazolin-3-one and 5-chloro- At least one compound having an isothiazolin-3-one skeleton selected from 2-methyl-4-isothiazolin-3-one, glycine, and a substituent on a nitrogen atom forming a 1,2,3-triazole ring And from the hydroxy group, carboxy group, sulfo group, amino group, carbamoyl group, carbonamido group, sulfamoyl group, and sulfonamide group at the 4-position and / or 5-position of 1,2,3-triazole. A substituent selected from the group consisting of: hydroxy group, carboxy group, sulfo group, amino group, carbamoyl group, carboxyla A heteroaromatic ring compound which is a 1,2,3-triazole derivative having an alkyl group or an aryl group substituted with at least one substituent selected from the group consisting of an amide group, a sulfamoyl group, and a sulfonamide group, or There is no substituent on the nitrogen atom forming the 1,2,4-triazole ring, and a sulfo group, a carbamoyl group, a carbonamido group is present at the 2-position and / or 5-position of the 1,2,4-triazole. Or a substituent selected from the group consisting of a sulfamoyl group and a sulfonamido group, or a group selected from the group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carbonamido group, a sulfamoyl group, and a sulfonamide group 1,2,4-triazole having an alkyl or aryl group substituted with at least one substituted group Polishing composition characterized by containing the heteroaromatic ring compound which is a conductor, a.