JP2008251730A - Polishing solution and substrate for semiconductor integrated circuit polished by using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing solution that exerts a quick polishing speed and excellent copper/barrier-metal polishing selectivity to a copper wiring, and also, improves planarity while having almost no dishing. <P>SOLUTION: The polishing solution includes a heterocyclic compound and polymer particles respectively having a functional group capable of forming a complex with copper ions in the side chain. As the functional group capable of forming a complex with copper ions, it is preferable to be an amino-carboxylic acid group, an amino-phosphorous acid group, an imino-diacetic acid group, an imino-diphosphoric acid group, their ester groups or their nitrile groups. As the heterocyclic compound, it is preferable to include at least one kind of a benzotriazole derivative, a tetrazole and a tetrazole derivative, and a triazole and a triazole derivative. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polishing liquid used for manufacturing a semiconductor device and a semiconductor integrated circuit substrate polished using the same, and more particularly, chemical mechanical planarization of a copper wiring provided on the semiconductor integrated circuit substrate. The present invention relates to a polishing liquid used for the above.

In the development of semiconductor devices typified by semiconductor integrated circuits (hereinafter referred to as “LSI”), high density and high integration by miniaturization and lamination of wiring are required for high integration and high speed. It has been. As a technique for this purpose, chemical mechanical polishing (Chemical Mechanical Polishing) that polishes an insulating thin film (SiO ₂ or the like) or a metal thin film used for wiring and smoothes the substrate or removes excess metal thin film during wiring formation. Various techniques such as Polishing, hereinafter referred to as “CMP”) have been used.
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.
A metal polishing solution used for CMP generally contains abrasive grains (eg, alumina, silica) and an oxidizing agent (eg, hydrogen peroxide, persulfuric acid), and oxidizes the metal surface with the oxidizing agent. It is thought that it is grind | polishing by removing the oxide film with an abrasive grain.

However, when CMP is performed using a polishing liquid containing such solid abrasive grains, scratches (scratches), a phenomenon in which the entire polished surface is polished more than necessary (thinning), the polished metal surface is not flat, A phenomenon in which the central part is polished deeper to form a dish-shaped dent (dishing), an insulator between metal wirings is polished more than necessary, and a plurality of wiring metal surface surfaces form dish-shaped recesses ( Erosion) may occur.
In order to solve such problems in the conventional solid abrasive grains, a polishing liquid which does not contain abrasive grains and is composed of hydrogen peroxide / malic acid / benzotriazole / ammonium polyacrylate and water is disclosed (for example, , See Patent Document 1). By using this polishing liquid, 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, but it is much more mechanical than conventional solid abrasive grains. In addition, since CMP proceeds due to friction with a soft polishing pad, it is difficult to obtain a sufficient polishing rate.

  On the other hand, an LSI using copper having low wiring resistance has been developed as a metal for wiring in place of conventional general-purpose tungsten or aluminum as a metal for wiring. Along with the miniaturization of wiring aiming at higher density, it is necessary to improve the conductivity and electron migration resistance of the copper wiring, and accordingly, use a copper alloy in which a small amount of a third component such as silver is added to high purity copper. This is beginning to be considered. 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.

  Recently, in order to improve productivity, the diameter of a wafer at the time of manufacturing an LSI has been increased. Currently, a diameter of 200 mm or more is widely used, and manufacture with a size of 300 mm or more has also started. With such an increase in size, the difference in polishing rate between the wafer center and the periphery has increased, and the demand for improvement in in-plane uniformity has increased.

As a chemical polishing method having no mechanical polishing means for copper and a copper alloy, a chemical polishing method using only a dissolving action is also known (see, for example, Patent Document 2). However, as compared with CMP in which the metal film of the convex portion is selectively chemically and mechanically polished, problems due to the occurrence of dishing and the like are likely to occur, and ensuring flatness is an issue.
In addition, for the purpose of flattening the level difference of the polishing surface, an aqueous dispersion for chemical mechanical polishing that suppresses deterioration of the polishing pad (see, for example, Patent Document 3), iminoniacetic acid useful for correcting the wafer surface, and its A processing fluid containing a chelating agent selected from salts (for example, see Patent Document 4), a chemical mechanical polishing composition containing an α-amino acid (for example, see Patent Document 5), and the like have been proposed.
By these polishing techniques, improvement in polishing performance in copper wiring can be seen. Usually, after high-speed polishing of copper wiring, tantalum or its alloys often used as a barrier metal of copper wiring and copper are polished precisely to smooth the vicinity of the wiring. For this reason, at the time of polishing copper wiring, the copper and barrier metal polishing selectivity (hereinafter referred to as “copper / barrier metal polishing selectivity” as appropriate) that copper is easily scraped and barrier metal such as tantalum is difficult to scrape. )) Is desirable.

JP 2001-127019 A JP 49-122432 A JP 2001-279231 A Special Table 2002-538284 Publication Special table 2003-507894 gazette

  The present invention has been made in order to increase the productivity of LSIs, and to realize faster polishing of wirings made of copper metal and copper alloy as raw materials. That is, the main object of the present invention is to provide a polishing capable of providing a rapid polishing speed and good copper / barrier metal polishing selectivity to copper wiring, and further improving flatness with less dishing. To provide liquid.

As a result of intensive studies, the present inventors have found that the above object can be achieved with the following polishing liquid, and have completed the present invention.
<1> A polishing liquid comprising polymer particles having a functional group capable of forming a complex with a copper ion in a side chain, and a heterocyclic compound.

<2> The functional group capable of forming a complex with the copper ion is an aminocarboxylic acid group, an aminophosphoric acid group, an iminodiacetic acid group, an iminodiphosphoric acid group, or an ester group thereof, or a nitrile group. The polishing liquid according to <1>.

<3> The polishing liquid according to <1> or <2>, wherein the heterocyclic compound contains a benzotriazole derivative.

<4> The polishing liquid according to <1> or <2>, wherein the heterocyclic compound contains at least one of tetrazole and a tetrazole derivative.

<5> The polishing liquid according to <1> or <2>, wherein the heterocyclic compound contains at least one of triazole and a triazole derivative.

<6> A substrate for a semiconductor integrated circuit, which is chemically and mechanically polished using the polishing liquid according to any one of <1> to <5>.

  ADVANTAGE OF THE INVENTION According to this invention, the polishing liquid which exhibits quick polishing speed and favorable copper / barrier metal polishing selectivity with respect to copper wiring, and can improve flatness with less dishing is provided. The

Hereinafter, a polishing liquid according to the present invention and a method for polishing a substrate for a semiconductor integrated circuit provided with a copper wiring using the polishing liquid will be described in detail.
The polishing liquid according to the present invention contains polymer particles having a functional group capable of forming a complex with copper ions in the side chain, and a heterocyclic compound. In the polishing liquid of the present invention, it is considered that the above-described polymer particles interact with copper ions, thereby improving the working efficiency as particles and consequently increasing the polishing rate.

<Polymer particles>
The polishing liquid of the present invention contains polymer particles having a functional group capable of forming a complex with copper ions. The functional group capable of forming a complex with the copper ion is a functional group capable of forming a complex with a copper ion derived from a metal film (copper wiring) to be polished. Specific examples of the functional group capable of forming a complex with a copper ion include a carboxyl group, a phosphoric acid group, a sulfonic acid group, a hydroxyl group, an amino group, preferably an aminocarboxylic acid group, an aminophosphoric acid group, an iminodiacetic acid group, Examples include imino diphosphate groups and nitrile groups, or ester groups of aminocarboxylic acid groups, amino phosphate groups, imino diacetic acid groups, and imino diphosphate groups, and imino diacetic acid groups are particularly preferable.

The polymer particles contained in the polishing liquid of the present invention are a monomer containing a functional group capable of complexing with copper ions and an olefinic double bond (hereinafter sometimes referred to as “functional group-containing monomer”). It can be obtained by polymerization. Thereby, the polymer particle containing the unit structure derived from the monomer containing the functional group which can form a complex with a copper ion, and an olefinic double bond can be obtained.
Here, as the functional group-containing monomer, for example, a monomer containing an aminocarboxylic acid group or an ester thereof and an olefinic double bond, an aminophosphate group or an ester thereof and an olefinic double bond are used. A monomer containing an iminodiacetic acid group or ester thereof and an olefinic double bond, a monomer containing an iminodiphosphate group or ester thereof and an olefinic double bond, a nitrile group And a monomer containing an olefinic double bond.

  Specific examples of the functional group-containing monomer in the present invention [compounds represented by formulas (M-1) to (M-8)] are shown below. However, the functional group-containing monomer for obtaining the polymer particles used in the polishing liquid of the present invention is not limited to these, and a functional group-containing monomer different from those exemplified below is used. Also good.

  As a production example of a functional group-containing monomer, for example, when producing a monomer containing an ester of iminodiacetic acid group and an olefinic double bond, a glycidyl ether group such as glycidyl (meth) acrylate, Examples thereof include a method in which an ester of iminodiacetic acid is added to a glycidyl ether group of a monomer containing an olefinic double bond. In order to obtain polymer particles having iminodiacetic acid groups, polymer particles are obtained by the method described later using the addition reaction product as a monomer, and then the iminodiacetic acid ester groups are hydrolyzed with a base. Then, although the iminodiacetic ester group at the terminal of the polymer particle is hydrolyzed, the (meth) acrylate group tends not to be hydrolyzed from the polymer particle.

The polymer particles used in the polishing liquid of the present invention further contain a monomer containing an olefinic double bond (hereinafter referred to as copolymerizable monomer) without containing a functional group capable of forming a complex with copper ions. In some cases, the structural unit may be included.
Examples of such copolymerizable monomers include: ethylene; α-olefin (eg, propylene, 1-butene, etc.); aromatic vinyl compound (eg, styrene, vinyl toluene, α-methylstyrene, etc.); ) Acrylic acid esters (for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, etc.), vinyl halide compounds (for example, vinyl chloride, vinylidene chloride, etc.); polyfunctional vinyl Aromatic compounds (eg, divinylbenzene, trivinylbenzene, divinyltoluene, divinylxylene, divinylnaphthalene, etc.); polyvinyl ethers or polyallyl ethers (eg, ethylene glycol divinyl ether, ethylene glycol diallyl ether, etc.); polyvalent (meth) Acrylate compounds (e.g. And ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and the like.

  In addition, as content of the structural unit derived from the functional group containing monomer in the polymer particle used by this invention, it is 20% or more normally with respect to polymer particle, Preferably it is about 55 to 75%. If the content of the structural unit is 20% or more, the polishing rate tends to be improved, which is preferable.

In order to improve the hardness of polymer particles, olefinic double bonds such as polyfunctional vinyl aromatic compounds such as divinylbenzene and polyvalent (meth) acrylate compounds such as ethylene glycol di (meth) acrylate are incorporated in the molecule. The polymer particles may contain structural units derived from a plurality of copolymerizable monomers.
The proportion of structural units derived from a copolymerizable monomer containing a plurality of olefinic double bonds in the polymer particles is usually 50% or less, preferably about 10% to 20%. .

As a method for polymerizing a monomer containing a functional group capable of forming a complex with a copper ion and an olefinic double bond, an ordinary method (for example, radical polymerization) can be used. For example, as a general synthesis method, a monomer and an initiator are dissolved in a solvent and the polymerization is carried out by heating, a batch polymerization method, emulsion polymerization, a solution of monomer species and an initiator in a heating solvent for 1 hour to 10 hours. Examples thereof include a dropping polymerization method which is added dropwise over time, and the dropping polymerization method is particularly preferable.
Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, cyclohexanone and the like can be mentioned.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon.

Examples of the polymerization initiator include redox polymerization initiators (for example, persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate, oxidizing agents such as hydrogen peroxide, L-ascorbate, and D-ascorbine. Acid, sulfite, phosphite, longalite, ferrous sulfate, tartaric acid, etc.), azo initiators (for example, azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2, 2′-azobis (2-methylpropionate) and the like).
A chain transfer agent such as a thiol compound may be used in combination with the polymerization initiator. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60 ° C to 100 ° C.

  When a monomer containing an ester group such as an aminocarboxylic acid group and an olefinic double bond is used as the functional group-containing monomer, the polymer containing the obtained polymer particles is converted to an alkali metal hydroxide. Products, alkaline earth metal hydroxides, alkali metal carbonates, alkali metal hydrogen carbonates, by hydrolysis with bases such as ammonia, carboxyl groups, phosphate groups, sulfonate groups, hydroxyl groups, amino groups, amino groups A method of inducing polymer particles having a carboxylic acid group, an aminophosphoric acid group, an iminodiacetic acid group, an iminodiphosphoric acid group or the like is preferable.

  The average particle diameter of the polymer particles used in the polishing liquid of the present invention is usually about 0.001 μm to 1 μm, and preferably about 0.005 μm to 0.5 μm. When the average particle size of the polymer particles is 0.001 μm or more, the stability of the polymer particles in the dispersion tends to be improved, and when the average particle size is 1.0 μm or less, dishing tends to be reduced. This is preferable.

The polishing liquid of the present invention contains the polymer particles obtained as described above as essential components, and when polishing using the polishing liquid of the present invention, the copper wiring has a high polishing rate and good copper / barrier metal polishing. In order to reliably achieve the selectivity and the reduction in the occurrence of dishing, the content of the polymer particles having a functional group capable of forming a complex with the copper ion in the polishing liquid in the side chain is preferably 0.00. 001-50 mass%, more preferably 0.01-10 mass%, particularly preferably 0.1-5 mass%.
The total content (% by mass) of the functional group-containing monomer and the hydrolysis product derived from the monomer (hereinafter sometimes referred to as residual monomer) is preferably 0.2% or less. More preferably, it is 0.1% or less. When the total content of the residual monomers is 0.2% or less, the etching rate of the copper wiring is remarkably suppressed at the time of polishing the semiconductor device, and dishing of the copper wiring can be extremely effectively prevented. Copper wiring can be polished at high speed.

<Heterocyclic compound>
The polishing liquid of the present invention contains a heterocyclic compound as a compound (passive film forming agent) that forms a passive film on the copper surface to be polished.

  The “heterocyclic compound” is a compound having a heterocyclic ring containing a hetero atom, and specific examples include a benzotriazole derivative, a tetrazole or tetrazole derivative, a triazole or triazole derivative, and the like.

The benzotriazole derivative that can be contained in the polishing liquid of the present invention will be described in detail.
The benzotriazole derivative contained in the polishing liquid of the present invention is a compound represented by the following formula (J) or (K) (hereinafter, appropriately referred to as “benzotriazole derivative”).

In the above formula, each of R ^{a to} R ^h independently represents a hydrogen atom, a carboxy group, a hydroxy group, an amino group, an alkyl group, an aryl group, a heterocyclic group, a nitro group, a halogen group, a sulfonyl group, or these groups. Represents a substituent contained as a partial structure. R ¹ and R ² represent a carboxy group, a hydroxy group, an amino group, an alkyl group, an aryl group, a heterocyclic group, or a substituent containing these groups as a partial structure.

  The benzotriazole derivative represented by the formula (J) or (K) includes a carboxy group, a hydroxy group, an amino group, an alkyl group, an aryl group, a heterocyclic group, a nitro group, a halogen group, and these groups in the molecule. It is mentioned as a preferred embodiment that at least one selected from the group consisting of substituents containing as a partial structure is introduced.

Examples of the substituent that can be introduced into R ¹ and R ² of formula (J) or (K) include a substituent containing a carboxy group as a partial structure, a substituent containing a hydroxyl group as a partial structure, and an amino group as a partial structure. Substituents and alkyl groups are preferred. Particularly preferred are N, N-bis (hydroxyethyl) aminomethyl, hydroxymethyl, 1,2-dicarboxyethyl, 2,3-dihydroxypropyl, carboxymethyl, carboxyethyl, and 2-aminocarboxy. It is an ethyl group.

  Specific examples of the benzotriazole derivative in the present invention [compounds represented by formula (A-1) to formula (A-21), formula (B1) to formula (B-18b)] are shown below, but are not limited thereto. Is not to be done.

In addition, the benzotriazole derivative which can be included in the polishing liquid of the present invention can be used alone or in combination of two or more.
The content of the benzotriazole derivative in the polishing liquid of the present invention is preferably 0.00001 to 5 mol, more preferably 0.00005 to 0.005 in 1 liter of the polishing liquid (use liquid) used for polishing. 5 mol.

The tetrazole or tetrazole derivative that can be contained in the polishing liquid of the present invention will be described in detail.
The tetrazole or tetrazole derivative is preferably an unsubstituted tetrazole or a tetrazole derivative containing a carboxyl group, an amino group, a hydroxy group, or an alkyl group substituted with at least one of them as a substituent. More preferably, it is an unsubstituted tetrazole or a tetrazole derivative containing at least one carboxy group or amino group. For example, 1H-tetrazole, 5-carboxy-1H-tetrazole, 1H-tetrazole-5-acetic acid, 1H-tetrazole-5-propionic acid, 5-amino-1H-tetrazole.

  The content of tetrazole or tetrazole derivative in the polishing liquid of the present invention is preferably 0.00001 to 5 mol, more preferably 0.00005 to 0.5 mol, in 1 L of the polishing liquid (use liquid) when used for polishing. It is.

The triazole or triazole derivative that can be contained in the polishing liquid of the present invention will be described in detail.
Examples of the triazole or triazole derivative include 1,2,3-triazole, 1,2,3-triazole derivative, 1,2,4-triazole, and 1,2,4-triazole derivative. Preferred are 1,2,3-triazole and 1,2,3-triazole derivatives.

  The 1,2,3-triazole or 1,2,3-triazole derivative is preferably an unsubstituted 1,2,3-triazole or a substituent selected from the group consisting of a hydroxy group, a carboxy group and an amino group Or a 1,2,3-triazole derivative containing, as a substituent, a group or an alkyl group substituted with at least one of these substituents. More preferably, it is an unsubstituted 1,2,3-triazole or a 1,2,3-triazole derivative containing at least one hydroxy group or an alkyl group substituted with at least one hydroxy group as a substituent. For example, 1H-1,2,3-triazole, 4-hydroxy-1H-1,2,3-triazole, 4-hydroxymethyl-1H-1,2,3-triazole, 4-1H-1,2,3 -Triazole.

  The 1,2,4-triazole derivative is preferably an unsubstituted 1,2,4-triazole, one substituted with a carboxyl group or a hydroxy group, or substituted with at least one of a hydroxy group and a carboxy group It is a 1,2,4-triazole derivative containing an alkyl group as a substituent. More preferably, it is an unsubstituted 1,2,4-triazole or a 1,2,4-triazole derivative containing at least one alkyl group substituted with at least one carboxy group as a substituent. For example, 1H-1,2,4-triazole, 3-hydroxy-1,2,4-triazole, 3,5-dicarboxy-1,2,4-triazole, 1,2,4-triazole-3-acetic acid Etc.

  The content of triazole or triazole derivative in the polishing liquid of the present invention is preferably 0.00001 to 5 mol, more preferably 0.00005 to 0.5 mol, in 1 liter of the polishing liquid (use liquid) used for polishing. It is.

The polishing liquid of the present invention is not particularly limited in its formulation except that it contains essential constituents, that is, polymer particles having a functional group capable of forming a complex with copper ions in the side chain and a heterocyclic compound. As long as the effects of the present invention are not impaired, compounds used in known polishing liquids can be selected and added depending on the purpose.
In general, the polishing liquid contains, for example, an oxidizing agent, an organic acid, and abrasive grains, but the polishing liquid of the present invention does not necessarily contain abrasive grains. On the other hand, the polishing liquid of the present invention may further contain other components. Examples of preferable other components include surfactants, water-soluble polymers, dispersants, preservatives, antifoaming agents, and various additives. An agent can be mentioned. Two or more of the above components may be added to the polishing liquid of the present invention.

  In the present invention, the “polishing liquid” is not limited to a polishing liquid used for polishing (that is, a polishing liquid diluted as necessary. In this specification, it may be referred to as “use liquid”). Including a concentrate of polishing liquid. Specifically, the concentrated liquid or the concentrated polishing liquid means a polishing liquid prepared with a higher solute concentration than the polishing liquid (use liquid) used for polishing. In this specification, “concentration” and “concentrated liquid” are used in accordance with conventional expressions meaning “thick” and “thick liquid” rather than the state of use, and involve physical concentration operations such as evaporation. The meaning of common terms is different.

Such concentrated liquid or concentrated polishing liquid is diluted with water or an aqueous solution when used for polishing. The dilution factor is generally 1 to 20 volume times.
In addition, when producing the concentrate of polishing liquid, it is preferable to consider the solubility of a structural component. For example, among the components to be added, the amount of the component having a solubility in water at room temperature of less than 5% by mass is the amount of solubility in water at room temperature in terms of preventing precipitation when the concentrate is cooled to 5 ° C. It is preferably within 2 times, more preferably within 1.5 times.

  Hereinafter, components other than the essential components that can be used in the polishing liquid of the present invention will be described.

<Oxidizing agent>
The polishing liquid of the present invention preferably contains a compound (oxidant) capable of oxidizing the metal (copper wiring) to be polished.
Specifically, hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, dichromium Examples thereof include acid salts, permanganates, ozone water, silver (II) salts, and iron (III) salts, and hydrogen peroxide is more preferably used.

  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 in 1 L of the polishing liquid used for polishing. Is particularly preferred. That is, the addition amount of the oxidizing agent is preferably 0.003 mol or more from the viewpoint of sufficiently oxidizing the copper to be polished to ensure a high CMP rate, and preferably 8 mol or less from the viewpoint of preventing roughening of the polished surface.

<Organic acid>
The polishing liquid of the present invention preferably contains an organic acid separately from the oxidizing agent. The organic acid here is a compound having a structure different from that of an oxidizing agent for oxidizing a metal, and does not include an acid that functions as the above-described oxidizing agent.
The organic acid is preferably water-soluble, and amino acids or other acids can be used.
As the amino acid, one selected from the following group is more suitable.
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 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-quinurenin, L-histidine, 1-methyl-L-histidine, 3-methyl -Amino acids such as L-histidine, ergothioneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin II and antipine.
Furthermore, the following general formula (1), general formula (2), and their ammonium salts and alkali metal salts are exemplified.

In general formula (1), R ¹ represents a single bond, an alkylene group, or a phenylene group. R ² and R ³ each independently 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. R ⁴ and R ⁵ each independently represents 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.

In general formula (2), R ⁶ represents a single bond, an alkylene group, or a phenylene group. R ⁷ and R ⁸ each independently 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. R ⁹ represents a hydrogen atom, a halogen atom, a carboxyl group, or an alkyl group. R ¹⁰ 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.

Hereinafter, although the specific example of the organic acid shown by General formula (1) and (2) is shown, it is not limited to this.

As the organic acid contained in the polishing liquid of the present invention, in particular, the amino acid derivatives containing the general formula (1) and the general formula (2) can effectively suppress the etching rate while maintaining a practical CMP rate. Is preferable.
As organic acids other than amino acids, those selected from the following group are more suitable.
Formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid , N-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, Examples thereof include tartaric acid, citric acid, lactic acid, hydroxyethyliminodiacetic acid, iminodiacetic acid, dihydroxyethylglycine, and salts such as ammonium salts and alkali metal salts thereof. Among these, malic acid, tartaric acid, citric acid, hydroxyethyliminodiacetic acid, iminodiacetic acid, dihydroxyethylglycine and the like are preferable in that the etching rate can be effectively suppressed while maintaining a practical CMP rate.

  The addition amount of the organic acid is preferably 0.0005 to 0.5 mol, more preferably 0.005 mol to 0.3 mol, and more preferably 0.01 mol to 1 mol in 1 L of the polishing liquid used for polishing. The amount is particularly preferably 0.1 mol. That is, the addition amount of the organic acid is preferably 0.5 mol or less from the viewpoint of suppressing etching, and 0.0005 mol or more is preferable for obtaining a sufficient effect.

  The polishing liquid of the present invention may further contain other components, and examples thereof include a surfactant, a hydrophilic polymer, and other additives.

<Surfactant / Hydrophilic polymer>
The polishing liquid of the present invention preferably contains a surfactant and a hydrophilic polymer.
Both the surfactant and the hydrophilic polymer have an effect of reducing the contact angle of the surface to be polished, and have an effect of promoting uniform polishing. As the surfactant and hydrophilic polymer added to the abrasive of the present invention, those selected from the following group are suitable.
Examples of the anionic surfactant include carboxylate, sulfonate, sulfate ester salt, phosphate ester salt and the like. Examples of the cationic surfactant include aliphatic amine salt, aliphatic quaternary ammonium salt, benzalkco chloride. Examples thereof include nium salts, benzethonium chloride, pyridinium salts, and imidazolinium salts. Examples of amphoteric surfactants include carboxybetaine type, aminocarboxylate, imidazolinium betaine, lecithin, alkylamine oxide and the like. Nonionic surfactants include alcohol type, amide type, ether type, ether ester type, ester type, nitrogen-containing type, and fluorine type surfactants.
Furthermore, examples of the hydrophilic polymer include polyglycols such as polyethylene glycol, polysaccharides such as polyvinyl alcohol, polovinyl pyrrolidone, and alginic acid, and carboxylic acid-containing polymers such as polymethacrylic acid and polyacrylic acid.

  Of the above, the acid or its ammonium salt is preferably free from contamination by alkali metals, alkaline earth metals, halides and the like. Among the above exemplified compounds, cyclohexanol, polyacrylic acid ammonium salt, polyvinyl alcohol, succinic acid amide, polo vinyl pyrrolidone, polyethylene glycol, and polyoxyethylene polyoxypropylene block polymer are more preferable.

  The weight average molecular weight of these surfactants and hydrophilic polymers is preferably from 500 to 100,000, particularly preferably from 2,000 to 50,000.

  The total amount of the surfactant and / or hydrophilic polymer added is preferably 0.001 to 10 g and more preferably 0.01 to 5 g in 1 L of a polishing liquid used for polishing. It is particularly preferably 0.1 to 3 g.

<PH adjuster>
In order to make the polishing liquid of the present invention have a predetermined pH, it is preferable to add an alkali, an acid, or a buffer as a pH adjuster.
Examples of the alkali, acid, or buffer include non-metallic alkaline agents such as organic ammonium hydroxides such as ammonium hydroxide and tetramethylammonium hydroxide, alkanolamines such as diethanolamine, triethanolamine, and triisopropanolamine. Alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, inorganic acids such as nitric acid, sulfuric acid and phosphoric acid, carbonates such as sodium carbonate, phosphates and borates such as trisodium phosphate Preferred examples include tetraborate and hydroxybenzoate. Particularly preferred alkali agents are ammonium hydroxide, potassium hydroxide, lithium hydroxide and tetramethylammonium hydroxide.

The addition amount of alkali, acid, or buffering agent may be an amount that maintains the pH of the polishing agent in a preferable range, and 0.0001 mol to 1.0 mol in 1 L of a polishing liquid used for polishing. It is preferable to do it, and it is more preferable to set it as 0.003 mol-0.5 mol.
3-12 are preferable, as for pH of the polishing liquid at the time of using for grinding | polishing, More preferably, it is 4-9, and 5-8 are especially preferable. The polishing liquid of the present invention can exhibit particularly excellent effects at a pH in the above range.

<Chelating agent>
The polishing liquid of the present invention may contain a chelating agent as necessary in order to reduce adverse effects such as mixed polyvalent metal ions. As a chelating agent, for example, a general-purpose hard water softening agent that is a precipitation inhibitor of calcium or magnesium or a similar compound thereof can be used, and two or more of these may be used in combination as necessary. The addition amount of the chelating agent may be an amount sufficient to sequester metal ions such as mixed polyvalent metal ions, for example, 0.0003 mol to 0.07 mol in 1 L of a polishing liquid used for polishing. Add to be.

<Antifoaming agent>
The polishing liquid of the present invention may further contain an antifoaming agent. Examples of the antifoaming agent include polyether type, special ester type, emulsion type, silicon base emulsion type, special nonion type, silicone type and the like. Of these, silicone-based emulsion type and silicone type antifoaming agents are preferred. When the polishing liquid of the present invention contains an antifoaming agent, two or more kinds may be contained.
The content (% by mass) of the antifoaming agent in the polishing liquid of the present invention is usually 0.0001 to 5%, preferably 0.005 to 3%, and more preferably 0.05 to 1%.

<Abrasive>
The polishing liquid of the present invention can also contain abrasive grains other than polymer particles. Examples of preferable abrasive grains include silica (precipitated silica, fumed silica, colloidal silica, synthetic silica), ceria, alumina, titania, zirconia, germania, manganese oxide, silicon carbide, polystyrene, polyacryl, polyterephthalate, and the like. However, it is more preferable to use colloidal silica.
The average grain size of the abrasive grains is preferably 5 nm to 1000 nm, particularly preferably 10 nm to 200 nm.
The addition amount of the abrasive grains is preferably 0.01 to 20% by mass with respect to the total mass of the polishing liquid in use when it is desired to exert the effect of the abrasive grains, and 0.05 to 5%. More preferably, it is in the range of mass%. For obtaining a sufficient effect by the abrasive grains, 0.01% by mass or more is preferable, and since the polishing rate by CMP is saturated, 20% by mass or less is preferable. However, it is particularly preferable that the polishing liquid of the present invention does not contain abrasive grains in order to sufficiently exhibit the copper / barrier metal polishing selectivity.

<Polishing target>
With respect to an object to be polished using the polishing liquid of the present invention, a semiconductor integrated circuit substrate having a copper wiring is suitable.
Among them, a substrate for a semiconductor integrated circuit to be polished (hereinafter sometimes referred to as “semiconductor device”) is preferably an LSI having a wiring made of copper metal and / or a copper alloy, particularly a copper alloy wiring. Is preferred. Furthermore, the copper alloy containing silver is preferable among copper alloys.
The content of silver contained in the copper alloy wiring is preferably 40% by mass or less in the copper alloy, particularly 10% by mass or less, more preferably 1% by mass or less, and 0.00001 to 0.1% by mass. The most excellent effect can be exhibited with respect to the copper alloy in the range.
The interlayer insulating film of a semiconductor device is not particularly limited, for example, SiO ₂ and the like.

<Thickness of wiring>
For semiconductor devices to be polished using the polishing liquid of the present invention, for example, in the case of a DRAM device system, the half pitch is preferably 0.15 μm or less, more preferably 0.10 μm or less, particularly What is 0.08 micrometer or less is preferable.
On the other hand, in the case of an MPU device system, the half pitch is preferably 0.12 μm or less, more preferably 0.09 μm or less, and particularly preferably 0.07 μm or less.
For such LSI, the polishing liquid of the present invention can exhibit particularly excellent effects.

<Barrier metal>
In the semiconductor device to be polished in the present invention, it is preferable that a barrier layer for preventing diffusion of copper is provided between a wiring made of copper metal and / or a copper alloy and an interlayer insulating film.
The barrier layer is preferably a low-resistance metal material, particularly TiN, TiW, Ta, TaN, W, or WN, and particularly preferably Ta or TaN.

  The size of the wafer (semiconductor integrated circuit substrate) to be subjected to CMP with the polishing liquid of the present invention is not particularly limited, but the diameter is preferably 200 mm or more, more preferably 300 mm or more. The effect of the present invention can be remarkably exhibited when the wafer diameter is 300 mm or more.

<Chemical mechanical planarization: polishing method>
A method for polishing the copper wiring of the substrate for a semiconductor integrated circuit by chemical mechanical polishing using the polishing liquid of the present invention is not particularly limited. For example, a general polishing apparatus that includes a holder for holding a semiconductor integrated circuit substrate to be polished, a motor whose rotation speed can be changed, and the like, and a polishing platen to which a polishing pad is attached is used. Then, the polishing liquid of the present invention is supplied to the polishing pad on the polishing surface plate, brought into contact with the surface to be polished of the substrate held by the holder, and polishing can be performed by relatively moving the surface to be polished and the polishing pad. preferable.

Preferred embodiments when using the polishing liquid of the present invention include, for example, (1) a concentrated liquid which is diluted by adding water or an aqueous solution when used for polishing, and (2) Examples include preparing each component in the form of an aqueous solution to be described later, mixing them, and adding water to dilute if necessary to obtain a working solution, and (3) a mode already prepared as a working solution.
Any of the above embodiments can be applied as a method for polishing using the polishing liquid of the present invention.

<Polishing pad>
The polishing pad is not particularly limited as long as it can be used for polishing the copper wiring of the semiconductor integrated circuit substrate, and may be a non-foamed structure pad or a foamed structure pad. The non-foamed structure pad uses a hard synthetic resin bulk material as a pad like a plastic plate. Further, the foam structure pad is further divided into three types, that is, an independent foam (dry foam system), a continuous foam (wet foam system), and a two-layer composite (laminated system). ) Is preferred. Foaming in the polishing pad may be uniform or non-uniform.
The polishing pad may further contain abrasive grains (for example, ceria, silica, alumina, resin, etc.) that can be included in the polishing liquid of the present invention. Moreover, the hardness of a polishing pad has a soft thing and a hard thing, Either can be used. In the laminated system, it is preferable to use one having a different hardness for each layer.
As the material for the polishing pad, non-woven fabric, artificial leather, polyamide, polyurethane, polyester, polycarbonate and the like are preferable. Further, the surface that comes into contact with the surface to be polished (substrate) may be subjected to processing such as lattice grooves, holes, concentric grooves, and spiral grooves.

The polishing conditions are not particularly limited, but the rotation speed of the polishing surface plate is preferably set to 200 rpm or less so that the substrate being polished does not pop out.
The rotation speed of the holder for holding the semiconductor integrated circuit substrate is not particularly limited.
The pressure applied to the polishing pad of the semiconductor integrated circuit substrate is preferably ⁵ to 500 g / cm ² , and 12 to 240 g / cm ² in order to further improve the uniformity of the polishing rate within the wafer surface and the flatness of the pattern. ² is more preferable.

During polishing, the polishing liquid of the present invention is continuously supplied to the polishing pad by a pump or the like. The supply amount of the polishing liquid is not particularly limited, but it is preferable that the surface of the polishing pad is always covered with the polishing liquid.
The polishing liquid supply rate is preferably 10 to 1000 ml / min, and more preferably 170 to 800 ml / min in order to further improve the uniformity of the polishing rate within the wafer surface and the flatness of the pattern.

  After the polishing, the semiconductor integrated circuit substrate is preferably thoroughly washed in running water, and then dried after removing water droplets adhering to the substrate using a spin dryer or the like.

When the substrate is polished using the polishing liquid of the present invention, the aqueous solution shown below can be used when diluting the concentrated liquid as in the method (1).
The aqueous solution for dilution is preferably an aqueous solution in which at least one of an oxidizing agent, an organic acid, an additive, and a surfactant is preliminarily contained in water, and is diluted with the components contained in this aqueous solution. A component obtained by adding up the components contained in the concentrated liquid is used as a polishing liquid used for polishing, that is, a component of the used liquid.
When the concentrated solution is diluted with an aqueous solution in this way, components that are difficult to dissolve can be added later in the form of an aqueous solution, so that a more concentrated concentrated solution can be prepared.

  Further, as a method of diluting by adding water or an aqueous solution to the concentrated liquid, for example, a pipe for supplying a concentrated polishing liquid and a pipe for supplying water or an aqueous solution are joined together and mixed, and diluted by mixing. There is a method of supplying a used liquid of the polishing liquid to the polishing pad. Mixing of concentrated liquid and water or aqueous solution is a method of colliding and mixing liquids through a narrow passage with pressure applied, filling the pipe with a filler such as a glass tube, and separating and separating the liquid flow. Ordinary methods such as a method of repeatedly performing and a method of providing blades that rotate by power in the pipe can be employed.

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

As yet another polishing method, the component to be contained in the polishing liquid of the present invention is divided into at least two components, and when these components are used, they are diluted by adding water or an aqueous solution to the polishing pad on the polishing platen. There is a method in which polishing is performed by supplying and contacting the surface to be polished of the substrate and moving the surface to be polished and the polishing pad relative to each other.
For example, an oxidant is used as the component (A), an organic acid, an additive, a surfactant, and water are used as the component (B). Each component (B) can be diluted.
Further, an additive having low solubility is divided into two constituent components (A) and (B). For example, an oxidizing agent, an additive, and a surfactant are used as the constituent component (A), and an organic acid, an additive, and a surface active agent are used. An agent and water can be used as the component (B), and when they are used, water or an aqueous solution can be added to dilute the component (A) and the component (B).

When performing the above-described dilution and mixing, for example, three pipes for supplying the component (A), the component (B), and water or an aqueous solution are provided, and these three pipes are further provided. There is a method in which a polishing pipe is connected to one pipe for supplying a polishing liquid and mixed in the pipe. In this case, it is possible to join two pipes and then join another pipe. Specifically, first, a constituent component containing an additive that is difficult to dissolve is mixed with another constituent component, the mixing path is lengthened to ensure a dissolution time, and further combined with a water or aqueous solution pipe. Is the method.
As other mixing methods, the above-mentioned three pipes are each guided directly to the polishing pad and mixed by relative movement of the polishing pad and the surface to be polished of the substrate, or three components are mixed in one container. Then, there is a method of supplying a diluted polishing liquid (use liquid) to the polishing pad.

  Further, when polishing is performed by supplying the polishing liquid of the present invention as described above, for example, the temperature of one component (A) containing an oxidizing agent is set to 40 ° C. or less, and the other component (B) The temperature is raised in the range of room temperature to 100 ° C., and when these components are mixed, or when diluted by adding water or an aqueous solution, the temperature of the polishing liquid is adjusted to 40 ° C. or lower. This method is a preferable method for increasing the solubility of a component having a low solubility in the polishing liquid by utilizing the phenomenon that the solubility increases at a high temperature.

  A part of the raw material in which the constituent component (B) is dissolved by heating in the range of room temperature to 100 ° C. may be precipitated in the solution when the temperature is lowered. When the component (B) in such a low temperature state is used, it may be heated in advance and the precipitated raw material may be dissolved. For this, there are means for feeding the component (B) in which the raw material is dissolved by heating, means for stirring the liquid containing the precipitate, and heating and dissolving the piping when feeding the liquid, etc. Can be adopted. In addition, since there exists a possibility that an oxidizing agent may decompose | disassemble when the temperature of the structural component (A) containing an oxidizing agent is raised to 40 degreeC or more with the heated structural component (B), this heated structural component (B) and When the component (A) containing an oxidizing agent is mixed, it is preferable that the temperature is 40 ° C. or lower.

  Thus, in the polishing method using the polishing liquid of the present invention, the components of the polishing liquid may be divided and supplied in two or more. In this case, it is preferable that the component containing the oxidizing agent and the component containing the organic acid be supplied separately. Alternatively, the polishing liquid may be a concentrated liquid, and diluted water may be separately supplied to the polishing surface.

Preferred embodiments in the present invention are as follows.
(1) A polishing liquid used for chemical mechanical planarization of semiconductor devices, containing a unit structure derived from a monomer containing a functional group capable of forming a complex with copper ions and an olefinic double bond A polishing liquid comprising polymer particles to be processed.
(2) The polishing liquid according to (1), comprising at least one benzotriazole derivative.
(3) The polishing liquid according to (1), comprising at least one tetrazole or a tetrazole derivative.
(4) The polishing liquid according to (1), which contains at least one triazole or triazole derivative.
(5) The functional group capable of forming a complex with a copper ion is a carboxyl group, a phosphoric acid group, a sulfonic acid group, a hydroxyl group, an amino group, an aminocarboxylic acid group, an aminophosphoric acid group, an iminodiacetic acid group, or an iminodiphosphoric acid. The polishing liquid according to any one of (1) to (4), which is a group, any of those ester groups, or a nitrile group.
(6) The polishing liquid according to (1) to (5), which contains at least one amino acid.
(7) The polishing liquid according to any one of (1) to (5), wherein the polishing liquid contains at least one compound represented by the general formula (1) or the general formula (2).

The polishing liquid of the present invention is extremely useful as a polishing liquid used for chemical mechanical planarization of copper wiring of a substrate for a conductor integrated circuit in a semiconductor device manufacturing process. That is, by using the polishing liquid of the present invention, the polishing rate and the copper / barrier metal (such as tantalum) polishing selectivity are excellent, and the flatness can be improved with less dishing.
This also makes it possible to maintain a low level of occurrence of defects due to local non-uniformity of polishing such as corrosion, scratching, thinning, and erosion in LSI.

  The polishing slurry for CMP of the present invention can be suitably used as a polishing material for a substrate on which a copper wiring such as a printed wiring board is formed in addition to a semiconductor device having an integrated circuit such as an LSI, a diode, a transistor, or a semiconductor chip.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

-Preparation of polymer particle-containing liquid-
Monomer (M-1), styrene, and divinylbenzene were charged and dissolved in propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 70/30 at a ratio of 70/10/20. To this solution, 6 mol% of a polymerization initiator V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added, and this was stirred at 80 ° C. for 2 hours in a nitrogen atmosphere. To this solution was further added 10 mol% of 10% aqueous potassium hydroxide solution, and the mixture was stirred at 50 ° C. for 5 hours.
This was concentrated, neutralized with hydrochloric acid, and then purified by electrodialysis (microacyler S3, manufactured by ASTOM, the same applies hereinafter. Dialysis conditions: automatic flow velocity, automatic voltage, the same applies hereinafter), and polymer particle-containing solution P was obtained. Obtained. In the polymer particle-containing liquid P, 15% by mass of polymer particles and 1.2% by mass of the component derived from the monomer (X-1) were contained.

<Example 1>
A polishing liquid having the composition shown below was prepared, and the polishing liquid of Example 1 was obtained. Further, this polishing liquid was evaluated by conducting a polishing test by the following method.

-Composition of polishing liquid-
・ Hydrogen peroxide (oxidant) ... 5g
・ Benzotriazole derivative A-1 ... 1.0 g
・ Polymer particle-containing liquid P ... 40 g
-Pure water: The amount in which the total amount becomes 1000 ml The pH of the polishing liquid was adjusted to 6.6 by using ammonia water and nitric acid.
The masses of the hydrogen peroxide, the benzotriazole derivative, and the polymer particles indicate the masses of these components themselves.

-Polishing test-
-Polishing pad: IC1400XY + K Groove (Rohm and Haas)
・ Polisher: LGP-612 (LapmaSterSFT)
・ Pressing pressure: 140 hPa
Polishing liquid supply rate: 200 ml / min
・ Copper blanket wafer: Wafer (diameter 200 mm) on which a copper film with a thickness of 1.4 μm is formed
Tantalum blanket wafer: Wafer (diameter 200 mm) on which a tantalum film with a thickness of 1 μm is formed
Pattern wafer: CMP854 pattern wafer (200 mm diameter) manufactured by atdf
Polishing pad / wafer rotation speed: 95/120 rpm
-Surface plate temperature control: 20 ° C
・ Temperature when supplying polishing liquid: 25 ° C

-Evaluation method-
Polishing rate: For 49 points on the copper blanket wafer surface and 49 points on the tantalum blanket wafer surface, the film thickness of the metal film before and after CMP is converted from the electrical resistance value, and the respective average polishing rate is obtained. It was. Further, the obtained polishing rate was introduced into the following formula, and the polishing rate ratio of copper and tantalum (copper / tantalum polishing rate ratio) was calculated.

(Copper / tantalum polishing rate ratio) = (average polishing rate of copper) / (average polishing rate of tantalum)

-Dishing: In addition to the time until copper of the non-wiring portion is completely polished on the pattern wafer, polishing is performed for a time corresponding to 30% of the time, and the line and space portion (line 100 μm, space 100 μm) Dishing was measured with a stylus profilometer.
Table 1 below shows the average copper polishing rate, dishing, and copper / tantalum polishing rate ratio obtained by performing CMP using the above polishing liquid.

<Examples 2 to 5>
In the composition of the polishing liquid of Example 1, the polishing liquids of Examples 2 to 5 were prepared in the same manner as in Example 1 except that the benzotriazole derivative A-1 was replaced with the passive film forming agent shown in Table 1, respectively. Prepared.
Using the resulting polishing liquid, the copper average polishing rate, dishing, and copper / tantalum polishing rate ratio were determined in the same manner as in Example 1. The results are also shown in Table 1.

<Example 6>
A polishing liquid having the composition shown below was prepared to obtain a polishing liquid of Example 6. Using the resulting polishing liquid, the copper average polishing rate, dishing, and copper / tantalum polishing rate ratio were determined in the same manner as in Example 1. The results are also shown in Table 1.

-Composition of polishing liquid-
・ Hydrogen peroxide (oxidant) ... 5g
・ Benzotriazole derivative A-1 ... 1.0 g
・ Polymer particle-containing liquid P 20 g
・ Organic acid X-1 ... 5g
-Pure water: The amount in which the total amount becomes 1000 ml The pH of the polishing liquid was adjusted to 6.6 by using ammonia water and nitric acid.
The masses of the hydrogen peroxide, the benzotriazole derivative, and the polymer particles indicate the masses of these components themselves.

<Comparative Example 1>
A polishing liquid having the composition shown below was prepared, and a polishing liquid of Comparative Example 1 was obtained. Using the resulting polishing liquid, the copper average polishing rate, dishing, and copper / tantalum polishing rate ratio were determined in the same manner as in Example 1. The results are also shown in Table 1.

-Composition of polishing liquid-
・ Hydrogen peroxide (oxidant) ... 5g
・ Glycine ... 10g
・ Benzotriazole (aromatic ring compound) ・ ・ ・ 1.5g
・ Colloidal silica (abrasive) ... 12g
-Pure water: The amount in which the total amount becomes 1000 ml The pH of the polishing liquid was adjusted to 6.6 by using ammonia water and nitric acid.
The masses of hydrogen peroxide, glycine, benzotriazole, and colloidal silica indicate the masses of these components themselves.

As shown in Table 1, the polishing liquid containing the polymer particles according to the present invention (Examples 1 to 6) has a significantly higher copper polishing rate than the polishing liquid not containing this (Comparative Example 1). It became clear that dishing was greatly improved without reducing it.
In addition, the polishing liquids of Examples 1 to 6 have a higher copper / tantalum polishing rate ratio than the polishing liquid of Comparative Example 1, and in particular, a polishing liquid containing a passive film forming agent preferable in the present invention (Examples 1 to 4). 6) was found to further improve the copper / tantalum polishing rate ratio as compared with the polishing liquid containing benzotriazole as a passive film forming agent (Example 5).
From these results, it can be seen that the polishing liquid of the present invention can be suitably used mainly for polishing a substrate having copper wiring.

Claims (6)

  A polishing liquid comprising polymer particles having a functional group capable of forming a complex with a copper ion in a side chain, and a heterocyclic compound.   The functional group capable of forming a complex with the copper ion is an aminocarboxylic acid group, an aminophosphoric acid group, an iminodiacetic acid group, an iminodiphosphoric acid group, or an ester group thereof, or a nitrile group. Item 10. The polishing liquid according to Item 1.   The polishing liquid according to claim 1, wherein the heterocyclic compound contains a benzotriazole derivative.   The polishing liquid according to claim 1, wherein the heterocyclic compound contains at least one of tetrazole and a tetrazole derivative.   The polishing liquid according to claim 1, wherein the heterocyclic compound contains at least one of triazole and a triazole derivative.   A substrate for a semiconductor integrated circuit, which has been chemically and mechanically polished using the polishing liquid according to claim 1.