JP2007299942A - Metal polishing composition, and chemical-mechanical polishing method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal polishing composition and a chemical-mechanical polishing method using it, which suppresses dishing or erosion with high cleaning property after polishing. <P>SOLUTION: The metal polishing composition contains (a) abrasive grain obtained by surface-modifying colloidal silica using ulmin acid ion or boric acid ion, and (b) a complex aromatic ring compound which comprises anionic substituent with three or more nitrogen atoms contained in molecule. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polishing composition, and more particularly to a metal polishing composition used in a wiring formation step in semiconductor device manufacture and a chemical mechanical polishing method using the same.

  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 the uniformity of polishing within the wafer surface becomes 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 for the purpose of preventing 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 a slurry 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 agent containing abrasive grains has a characteristic that a high polishing rate can be obtained. However, when the pH of the polishing liquid is neutral to acidic, the abrasive grains tend to aggregate, and dishing progresses or scratches occur. It was. As neutral to acidic and stable abrasive grains, Patent Document 5 discloses a polishing composition using colloidal silica surface-modified with boron as abrasive grains, and Patent Document 6 discloses a part of the surface of silica particles. Alternatively, colloidal silica for surface polishing coexisting with a metal insulating film entirely covered with aluminum is disclosed. Abrasive grains imparted with a negative charge by surface modification with these boron and aluminum can prevent aggregation from neutral to acidic, but the surface potential of metals such as copper is normally positively charged from neutral to acidic. Therefore, there are problems that dishing and erosion occur due to the abrasive particles electrostatically adsorbed on the metal surface, and that the abrasive particles adsorb to the metal surface after polishing and the detergency is poor.
US Pat. No. 4,944,836 JP-A-2-278822 JP 49-122432 A JP 2001-127019 A JP 2003-183631 A JP 2003-197573 A Journal of Electrochemical Society, 1991, Vol. 11, No. 11, pages 3460-3464 Journal of Electrochemical Society, 2000, Vol. 147, No. 10, pages 3907-3913

  An object of the present invention is to provide a metal polishing composition with good cleaning properties after polishing, which suppresses dishing and erosion, and also provides a chemical mechanical polishing method using the metal polishing composition. There is to do.

In view of the above circumstances, the present inventors have conducted extensive research and found that the above problems can be solved, thereby completing the present invention.
That is, the present invention is achieved by the following means.

<1> (a) Abrasive grains obtained by surface modification of colloidal silica with aluminate ions or borate ions, and (b) a complex having an anionic substituent and having three or more nitrogen atoms in the molecule. A metal polishing composition comprising an aromatic ring compound.
<2> (a) Abrasive grains obtained by surface modification of colloidal silica with aluminate ions or borate ions, and (b) a complex having an anionic substituent and having three or more nitrogen atoms in the molecule. The metal according to the above <1>, comprising an aromatic ring compound and (c) a heteroaromatic ring compound having 3 or more nitrogen atoms in the molecule and having no anionic substituent. Polishing composition.

<3> The metal polishing composition as described in <1> or <2> above, wherein the pH of the metal polishing composition is 3 to 7.
<4> The metal polishing material according to any one of <1> to <3>, wherein a surface to be polished when the metal polishing composition is polished is copper or a copper alloy. Composition.

<5> (a) Abrasive grains obtained by surface modification of colloidal silica with aluminate ions or borate ions, and (b) a complex having an anionic substituent and having three or more nitrogen atoms in the molecule. A chemical mechanical polishing method comprising polishing at a polishing pressure of 3 psi (0.0207 MPa) or less using a metal polishing composition containing an aromatic ring compound.
<6> (a) Abrasive grains obtained by surface modification of colloidal silica with aluminate ions or borate ions, and (b) a complex having an anionic substituent and having three or more nitrogen atoms in the molecule. Using a metal polishing composition containing an aromatic ring compound and (c) a heteroaromatic ring compound having 3 or more nitrogen atoms in the molecule and having no anionic substituent, the polishing pressure is 3 psi ( The chemical mechanical polishing method according to <5>, wherein polishing is performed at 0.0207 MPa or less.

According to the present invention, it is possible to provide a metal polishing composition with good cleanability after polishing which prevents electrostatic adsorption of negatively charged abrasive grains to a metal surface and suppresses dishing and erosion. it can.
In addition, a chemical mechanical polishing method using the metal polishing composition can be provided.

[Metal polishing composition]
The metal polishing composition of the present invention comprises (a) abrasive grains obtained by surface modification of colloidal silica with aluminate ions or borate ions, (b) anionic substituents, and three in the molecule. And a heteroaromatic ring compound having the above nitrogen atom.
Moreover, you may contain another compound as needed.
The metal 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 obtained by dissolving each component.
The metal 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 metal polishing composition of this invention, pH is 3-7, More preferably, pH is 4-7.
When the pH is less than 3, aggregation tends to occur, and when the pH exceeds 7, dishing may deteriorate.

  Although each component which comprises a metal polishing composition is explained in full detail below, each component may use only 1 type and may use 2 or more types together.

  In the present invention, the metal polishing composition (hereinafter also referred to as “polishing composition”) is not limited to the composition (concentration) used for polishing, but may be used as diluted as necessary during use. In the present invention, unless otherwise specified, it is referred to as a metal polishing composition. 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 surface-modified with aluminate ions or borate ions>
The polishing composition of the present invention contains (a) colloidal silica surface-modified with aluminate ions or borate ions (hereinafter referred to as “specific colloidal silica” as appropriate).
The specific colloidal silica functions as an abrasive in the polishing composition of the present invention.

In the present invention, “colloidal silica surface-modified with aluminate ions or borate ions” means that an aluminum atom or a boron atom is present on the surface of colloidal silica having a site containing a silicon atom having a coordination number of 4. It means that there is a state.
For example, an aluminum atom coordinated with four oxygen atoms may be bonded to the colloidal silica surface to form a new surface in which the aluminum atom is fixed in a four-coordinate state. It may be in a state in which silicon atoms present in the metal are once extracted and a new surface replacing aluminum atoms is generated.
Further, the surface of the colloidal silica may be bonded to a boron atom coordinated with four oxygen atoms, and a new surface in which the boron atom is fixed in a four-coordinate state may be generated. It may be in a state in which a silicon surface existing on the surface is once extracted and a new surface is formed in which the boron atom is replaced.

The colloidal silica used for the preparation of the specific colloidal silica is more preferably a colloidal silica obtained by hydrolysis of alkoxysilane that does not contain impurities such as alkali metals inside the particles. On the other hand, although colloidal silica produced by a method of removing alkali from an alkali silicate aqueous solution can also be used, in this case, there is a concern that the alkali metal remaining in the particles gradually elutes and affects the polishing performance. Therefore, from such a viewpoint, a material obtained by hydrolysis of the alkoxysilane is more preferable 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.

-(A1) Colloidal silica surface-modified with aluminate ion-
As a method for obtaining a specific colloidal silica by replacing silicon atoms on the surface of the 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. it can. 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.

  The specific colloidal silica is acidic in that the aluminosilicate site generated by the reaction between the tetracoordinate aluminate ion and the silanol group on the surface of the colloidal silica fixes a negative charge and gives the particle a large negative zeta potential. 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 preferably such that the surface atom substitution rate (number of introduced aluminum atoms / number of surface silicon atom sites) of colloidal silica is 0.001% or more and 20% or less. 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 impurities by ion exchange, ultrafiltration, etc., and obtaining specific colloidal silica is mentioned.

-(A2) Colloidal silica surface-modified with borate ions-
As a method for obtaining a specific colloidal silica by substituting a silicon atom on the surface of the colloidal silica particle with a boron atom, for example, it can be obtained by modifying the surface of the colloidal silica using boric acid and a silane coupling agent. These methods are described in detail in JP-T-2003-525191, EP943648, EP941995, and this description can be applied to the present invention.
Specific colloidal silica is dispersed even in acidity by the site generated by the reaction of tetracoordinate borate ions and silanol groups on the surface of colloidal silica fixing negative charges and giving the particles a large negative zeta potential. Excellent in properties. Therefore, it is important that the specific colloidal silica produced by the method as described above exists in a state where the boron atom is coordinated to four oxygen atoms.

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

  The zeta potential on the colloidal silica surface is 0 to -10 mV at pH 3 to pH 5, but decreases to -10 to -20 mV by treatment with borate ions. Although it is −10 mV to −20 mV at pH 5 to pH 7, it decreases from −20 mV to −40 mV by treatment with borate ions.

The amount of substitution of silicon atoms on the surface of the colloidal silica with boron atoms is such that the surface atom substitution rate (number of introduced boron atoms / number of surface silicon atom sites) of the 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 replacing silicon atoms on the surface of colloidal silica with boron atoms, the amount of substitution with boron atoms should be controlled appropriately by controlling the amount (concentration) of the boric acid compound added to the colloidal silica dispersion. Can do.

The preparation of colloidal silica surface-modified with boric acid will be described below, but is not limited thereto.
For example, boric acid powder (268 g) is dissolved in ultrapure water (5.6 kg) to prepare a boric acid solution.
Next, a 20% colloidal silica solution (colloidal silica having an average particle diameter of 20 nm) dealkalized with an H-type ion exchange resin is slowly added to the boric acid solution (about 1.2 ml at a speed of about 200 ml / min). In addition, 10 g of tetramethoxysilane is added and the mixture is maintained at temperature (55 ° C.-60 ° C.) with stirring. After completion of the addition, the mixture is stirred (5.5 hours) while being heated (about 60 ° C.).
Subsequently, the obtained solution is filtered through a 1 micron (1 μm) ceramic filter to obtain colloidal silica surface-modified with boron.

  In the present invention, the size (volume equivalent diameter) of the colloidal silica surface-modified with the above-mentioned aluminate ions or borate ions, that is, the specific colloidal silica is preferably 3 to 200 nm, more preferably 5 to 100 nm. 10 nm to 60 nm is particularly preferable. 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 the specific colloidal silica is preferably equal to or greater than twice the specific colloidal silica.

<(B) Heteroaromatic ring compound having an anionic substituent and having 3 or more nitrogen atoms in the molecule>
The polishing composition of the present invention has a heteroaromatic ring compound having an anionic substituent as the component (b) and having three or more nitrogen atoms in the molecule (hereinafter also referred to as (b) heteroaromatic ring compound). .) As an essential component.
One type may be used alone, or two or more types may be used in combination.

  Examples of the heteroaromatic ring compound having an anionic substituent and having three or more nitrogen atoms in the molecule include tetrazole derivatives, 1,2,3-triazole derivatives, and 1,2,4- A triazole derivative is preferred.

(Tetrazole derivatives)
There is no substituent on the nitrogen atom forming the tetrazole ring, and an anionic substituent at the 5-position of tetrazole (for example, carboxyl group, sulfo group, hydroxyl group, amino group, carbamoyl group, carbonamido group, sulfamoyl group) And a substituent having a group selected from the group consisting of sulfonamide groups, preferably a carboxyl group, a sulfo group, and more preferably a carboxyl group).

(1,2,3-triazole derivative)
There is no substituent on the nitrogen atom forming the 1,2,3-triazole ring, and an anionic substituent (for example, carboxyl group, sulfo group at the 4-position and / or 5-position of 1,2,3-triazole) A substituent having a group selected from the group consisting of a group, a hydroxyl group, an amino group, a carbamoyl group, a carbonamido group, a sulfamoyl group, and a sulfonamido group, preferably a carboxyl group, a sulfo group, and more preferably a carboxyl group) 1,2,3-triazole derivative characterized by having.

(1,2,4-triazole derivative)
There is no substituent on the nitrogen atom forming the 1,2,4-triazole ring, and an anionic substituent (for example, carboxyl group, sulfo group at the 3-position and / or 5-position of 1,2,4-triazole) A substituent having a group selected from the group consisting of a group, a hydroxyl group, an amino group, a carbamoyl group, a carbonamido group, a sulfamoyl group, and a sulfonamido group, preferably a carboxyl group, a sulfo group, and more preferably a carboxyl group) 1,2,4-triazole derivative characterized by having.

  Specific examples of the (b) heteroaromatic ring compound in the present invention include the following exemplified compounds (I-2) to (I-4) and (I-6) to (I-16). It is not limited to.

  The amount of the (b) heteroaromatic ring compound added in the polishing composition of the present invention is preferably 0.0001% by mass or more and 0.005% by mass or less, and more preferably, with respect to 1 kg of the polishing composition. 0.0005 mass% or more and 0.002 mass% or less.

  Furthermore, examples of the (b) heteroaromatic ring compound include benzotriazole-4-carboxylic acid, benzotriazole-4-sulfonic acid, and the like.

<(C) Heteroaromatic ring compound having 3 or more nitrogen atoms in the molecule and having no anionic substituent>
The metal polishing composition of the present invention comprises (c) a heteroaromatic ring compound having 3 or more nitrogen atoms in the molecule and having no anionic substituent (hereinafter referred to as “(c) heteroaromatic ring compound”). It is preferable to contain.
By containing the (c) heteroaromatic ring compound, the negative charge density of the passive film on the copper surface can be adjusted.
In the present invention, (c) the heteroaromatic ring compound having three or more nitrogen atoms in the molecule and having no anionic substituent includes the anion in the aromatic ring of the (b) heteroaromatic ring compound. And a heteroaromatic ring compound having no functional substituent.
That is, it is a compound having only a heteroaromatic ring and having no substituent bonded to the heteroaromatic ring.

  The addition amount of the (c) 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 based on 1 kg of the polishing composition. 0.0005 mass% or more and 0.002 mass% or less.

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

<(D) Surfactant and / or hydrophilic polymer>
The polishing composition of the present invention can contain (d) 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, pectic 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.

<(E) Compound (amino acid) having at least one carboxyl group and at least one amino group in the molecule>
The polishing composition of the present invention can contain (e) 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: Is suitable.

  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 acid or aminopolyacid that can be used in the present invention is preferably an amino acid or aminopolycarboxylic acid, and particularly preferably a compound represented by the following formula (1) or formula (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.
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 as 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.
The alkylene chain in the compound represented by the general formula (I) may have a hetero atom such as an oxygen atom or a sulfur atom. Here, the alkylene chain refers to a case where, for example, when the alkyl group is divided into a terminal part and a connecting part, the connecting part is an alkylene group.

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 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.
Examples of the substituent that each group as 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.
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.
The alkylene chain in the compound represented by the general formula (I) may have a hetero atom such as an oxygen atom or a sulfur atom. Here, the alkylene chain refers to a case where, for example, when the alkyl group is divided into a terminal part and a connecting part, the connecting part is an alkylene group.

  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 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 is 0.1% by mass or more and 5% by mass from the viewpoint of both polishing speed and flatness. % By mass or less is preferable, and 0.5% by mass to 2% by mass is 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.
The pH in the polishing composition of the present invention is as described above.

<(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-hydroxybenzidine ) Ethylenediamine -N, it includes 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, and 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.

[Wiring thickness]
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 3 psi (0.0207 MPa) or less, preferably 0.1 to 2 psi (0.00069 MPa to 0.0138 MPa). More preferably, in order to satisfy the uniformity of the polishing rate within the wafer surface and the flatness of the pattern, it is more preferably 0.5 to 1.5 psi (0.00345 MPa to 0.0104 MPa).

During polishing, the polishing composition is continuously supplied to the polishing pad with a pump or the like. Although the supply amount is not limited, it is preferable that the surface of the polishing pad is always covered with the polishing composition.
After the polishing, the semiconductor substrate 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. When the polishing composition of the present invention is used, polishing is performed. The subsequent detergency becomes good. This is presumed to be due to electrostatic repulsion between the abrasive grains and the wiring metal.
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, the pipe for supplying the concentrated polishing composition and the pipe for supplying the water are mixed together and mixed, mixed and diluted for polishing. There is a method of supplying a composition to a 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 an aqueous solution or the like, a pipe for supplying the polishing composition and a pipe for supplying water or an aqueous solution are independently provided, and a predetermined amount of liquid is supplied from each of them. And polishing while 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 are mixed in one container and then mixed, and then the mixed polishing composition is supplied to a polishing pad for polishing.

In another polishing method of the present invention, the component to be contained in the polishing composition is divided into at least two components, and when these components are used, they are diluted by adding water and supplied to the polishing pad on the polishing platen. In this method, the surface to be polished and the polishing pad are moved relative to each other and brought into contact with the surface to be polished.
For example, an oxidant is one component (A), an acid, an additive, a surfactant, and water are one component (B), and when they are used, the component (A) and the component are made with water. Dilute (B) for 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 components are used, water is added to dilute component (A) and component (B).
In this example, three pipes for supplying the component (A), the component (B), and water are required, and dilution mixing is performed by combining the three pipes into one pipe that supplies the polishing pad. There is a method of mixing in the pipe. In this case, it is also possible to combine the two pipes and then connect the other one pipe.

For example, a component containing an additive that hardly dissolves is mixed with another component, a mixing path is lengthened to ensure a dissolution time, and then a water pipe is further coupled.
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 are added. When diluting and using, it can also be made 40 degrees C or less 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 colloidal silica (A-1) treated with aluminate]
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 ammine acid-treated colloidal silica (A-1) was 40 nm, and the aluminum coating amount determined by the above-described method was 1%. Moreover, the thickening and gelation after preparation were not seen for the ammine acid-treated specific colloidal silica (A-1).

[Preparation of colloidal silica (A-2) treated with boric acid]
A boric acid solution was prepared by dissolving 268 g of boric acid powder in 5.6 kg of ultrapure water.
Next, colloidal silica (product name: Quattron PL-3, manufacturer: Fuso Chemical) with an average abrasive grain size (average primary particle diameter) of 35 nm obtained by hydrolyzing tetraethoxysilane into this boric acid solution. 15000 g of a 20% by weight aqueous dispersion is slowly added over a period of about 1.2 hours at a rate of about 200 ml / min. Further, 10 g of tetramethoxysilane is added, and the temperature is changed from 55 to 60 ° C. while stirring the mixture. Maintained. After completion of the addition, the mixture was stirred for 5.5 hours while being heated to about 60 ° C.
Subsequently, the obtained solution was filtered through a 1 micron (1 μm) ceramic filter to obtain colloidal silica (A-2) surface-modified with boron.

[Preparation of polishing composition]
The polishing composition of Example 1 was prepared with the composition shown below using the ammine acid-treated 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-
・ (A) Abrasive grains (Ammic acid-treated colloidal silica (A-1)) 50 g / L
(B) Heteroaromatic ring compound (1,2,3 triazole-4,5 carboxylic acid) 50 mg / L
(E) Amino acid (glycine) 10 g / L
・ (H) Oxidizing agent (30% hydrogen peroxide) 15g / L

(Example 2)
In Example 1, instead of 1,2,3-triazole-4,5-carboxylic acid, 1,2,3,4-tetrazole-5-acetic acid was added and the abrasive grains were changed to A-2. A polishing composition of Example 2 was prepared in the same manner as Example 1.

(Example 3)
In Example 1, except that 1,2,3-triazole-4,5-dicarboxylic acid and 1,2,3-triazole were added instead of 1,2,3-triazole-4,5-dicarboxylic acid. A polishing composition of Example 3 was prepared in the same manner as Example 1.

(Comparative Example 1)
In Example 1, a comparative polishing composition was prepared in the same manner as in Example 1 except that 1,2,3-triazole was added instead of 1,2,3-triazole-4,5-dicarboxylic acid. Prepared.

(Comparative Example 2)
In Example 1, instead of 1,2,3-triazole-4,5-dicarboxylic acid, 1,2,3,4-tetrazole was added and the abrasive grains were changed to A-2. A comparative polishing composition was prepared in the same manner as described above.

  After preparing the polishing composition (polishing liquid) prepared in Examples 1 to 3 and Comparative Examples 1 and 2 and storing it at room temperature for 6 months, polishing was performed by the following polishing method to obtain polishing performance (dishing, erosion) ) Was evaluated. The evaluation results are shown in Table 3.

(Polishing test)
The apparatus provided by Lappmaster Co., Ltd. “LGP-612” was used as a polishing apparatus, and the film provided on each wafer was polished under the following conditions while supplying slurry.
-Substrate: (1) Silicon wafer with 8 inch copper film (2) For erosion evaluation; Copper wiring wafer (pattern wafer) with a diameter of 200 mm (Mask pattern 754CMP (ATDF))
Table rotation speed: 64 rpm
-Head rotation speed: 65 rpm
(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-Polishing rate measurement: Film pressure was converted from electrical resistance before and after polishing. Specifically, the measurement was performed by polishing rate (nm / min) = (thickness of copper film before polishing−thickness of copper film after polishing) / polishing time.

<Evaluation>
1. Dishing evaluation A 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. Further, sputtering is performed. A Ta film having a thickness of 20 nm was formed by the method, a copper film having a thickness of 50 nm was subsequently formed by a sputtering method, and then a wafer having a copper film having a total thickness of 1000 nm formed by plating was cut into 6 × 6 cm.
Under this condition, the substrate is polished while supplying slurry onto the polishing cloth of the polishing surface plate of the polishing apparatus, and in addition to the time until the copper in the non-wiring portion is completely polished, 30% of the time Polishing was carried out by an extra amount (overpolish 30%), and the level difference in the line and space part (line 100 μm, space 100 μm) was measured using a stylus type level gauge to obtain dishing.

2. Erosion Evaluation In addition to the time until the copper in the non-wiring portion is completely polished on the same substrate as the pattern wafer for dishing, an extra polishing is performed for 20% of that time (overpolish 20%) Then, the step of the line and space part (line 100 μm, space 100 μm) was measured with a contact-type step gauge Dektak V3201 (Veeco).

3. Evaluation of Cleaning Effect As a device for detecting foreign matter on a wafer, there is a light scattering type foreign matter measuring device (for example, SP1-TB1 manufactured by KLA Tencor). In this type of device, in order to detect foreign matter on the wafer, a laser beam is not incident on the wafer surface and the specularly reflected light of this laser beam is detected, but a photodetector arranged in a predetermined direction. The foreign matter on the wafer is detected by measuring the light intensity of the laser light scattered by. Laser light sequentially scans the wafer surface, but if non-uniform portions such as foreign matter are present on the wafer surface, the scattering intensity changes. By comparing this scattered light intensity with the scattered light intensity calibrated with the standard particles in advance, this apparatus can display the size and position of the foreign matter obtained by converting the scattered light intensity with the standard particles.

The number of particles remaining on the surface after polishing and drying was evaluated by measuring the number of defects using SP1-TB1 manufactured by KLA-TENCOR after polishing, washing and drying with water. Furthermore, as a result of observing the surface with SEM (scanning electron microscope) and examining the number of silica particles per unit area, the particle removability could be classified into three as follows. The SEM used was JSM T220A manufactured by JEOL.
○: Almost no abrasive grains remaining (less than 100 / wafer)
Δ: Abrasive grains remaining (100 to less than 1000 pieces / wafer)
×: Abrasive grain residue remaining (1000 or more / wafer)

  As is apparent from Table 3, an example using a polishing composition containing specific abrasive grains and (b) a heteroaromatic ring compound having an anionic substituent and having three or more nitrogen atoms in the molecule. Was found to show an excellent effect in any case.

Claims (6)

(A) Abrasive grains obtained by surface modification of colloidal silica with aluminate ions or borate ions, and (b) a heteroaromatic ring compound having an anionic substituent and having three or more nitrogen atoms in the molecule. And a metal polishing composition comprising: (A) Abrasive grains obtained by surface modification of colloidal silica with aluminate ions or borate ions; (b) Heteroaromatic compounds having an anionic substituent and having three or more nitrogen atoms in the molecule And (c) a heteroaromatic ring compound having three or more nitrogen atoms in the molecule and having no anionic substituent, The metal polishing composition according to claim 1, . The metal polishing composition according to claim 1 or 2, wherein the metal polishing composition has a pH of 3 to 7. 4. The metal polishing composition according to claim 1, wherein a surface to be polished when the metal polishing composition is polished is copper or a copper alloy. 5. (A) Abrasive grains obtained by surface modification of colloidal silica with aluminate ions or borate ions; (b) Heteroaromatic compounds having an anionic substituent and having three or more nitrogen atoms in the molecule And a metal-mechanical polishing composition comprising: a polishing pressure of 3 psi (0.0207 MPa) or less. (A) Abrasive grains obtained by surface modification of colloidal silica with aluminate ions or borate ions; (b) Heteroaromatic compounds having an anionic substituent and having three or more nitrogen atoms in the molecule And a polishing pressure of 3 psi (0.0207 MPa) using a metal polishing composition containing (c) a heteroaromatic ring compound having three or more nitrogen atoms in the molecule and having no anionic substituent. 6. The chemical mechanical polishing method according to claim 5, wherein polishing is performed as follows.