JP2009081300A - Metal polishing composition and polishing method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal polishing composition which has an excellent polishing speed to a conductor film composed of copper or a copper alloy and is capable of suppressing the occurrence of dishing, and to provide a polishing method using the same. <P>SOLUTION: The metal polishing composition which contains respective components as follows and is used for chemical-mechanical polishing in the manufacture process of a semiconductor device and the polishing method using the same are provided: (1) peroxodisulfate; (2A) an anion surface active agent having at least one sulfo group or its salt in a molecule; (2B) an anion surface active agent having at least one carboxyl group or its salt in the molecule; and (3) a heteroaromatic ring compound. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal polishing composition and a polishing method using the same, and more particularly, to a metal polishing composition used when performing chemical mechanical planarization in a semiconductor device manufacturing process and the same. It relates to the polishing method used.

In the development of semiconductor devices typified by semiconductor integrated circuits (hereinafter sometimes referred to as “LSI”), in order to increase the integration and speed of semiconductor devices, wiring miniaturization and lamination methods are studied. Has been. As a technique for this purpose, various techniques such as chemical mechanical polishing (hereinafter sometimes referred to as “CMP”) are employed. CMP is used to polish an interlayer insulating film (such as SiO ₂ ) or a metal thin film used for wiring to smooth the substrate or remove an excess metal thin film during wiring formation (for example, patents). Reference 1).

A general method of CMP is as follows.
A polishing pad is affixed on a circular polishing platen (platen), and the surface of the polishing pad is immersed in a polishing liquid. The surface of the substrate (wafer) is pressed against the polishing pad, and both the polishing platen and the substrate are rotated with a predetermined pressure (polishing pressure) applied from the back surface.
In CMP, the surface of a substrate is flattened by mechanical friction generated by the above operation.

  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. A damascene method is known as a method for wiring copper (see, for example, Patent Document 2). 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 is shipped.

  However, in recent years, in order to miniaturize the wiring in accordance with the demand for higher density, improvements in the conductivity and electronic characteristics of the copper wiring are required. On the other hand, the use of a copper alloy obtained by adding a third component to high-purity copper has begun to be studied.

  There is also a need for high-speed metal polishing means that can increase productivity without contaminating high-definition and high-purity materials. In particular, since copper is a soft metal, when polishing copper or copper alloys, only the center is polished deeper, resulting in dish-like depressions (dishing), or the surface of multiple wiring metal surfaces is a dish. A phenomenon (erosion) that forms a concave-shaped recess and a polishing flaw (scratch) are likely to occur, and an increasingly accurate polishing technique is required.

  In recent years, wafers have become larger in order to improve productivity. Currently, wafers with a diameter of 200 mm or more are widely used, and the manufacture of wafers with a diameter of 300 mm or more has started. As the size of the wafer increases, the difference in polishing rate between the central portion and the peripheral portion of the wafer tends to increase, and there is a strong demand for uniform polishing within the wafer surface.

  On the other hand, as a chemical polishing method in which mechanical polishing means is not applied to copper and a copper alloy, a chemical polishing method based only on a dissolving action is disclosed (for example, see Patent Document 3). However, since such a chemical polishing method polishes only by a chemical dissolution action, there is a problem such as recess recessing, that is, dishing, as compared with CMP in which the metal film of the protrusion is selectively chemically and mechanically polished. Is likely to occur, and flatness is a problem.

In addition, when copper wiring is used in LSI manufacturing, a diffusion prevention layer called a barrier film 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 film is formed of a barrier material such as TaN, TaSiN, Ta, TiN, Ti, Nb, W, WN, Co, Zr, ZrN, Ru, CuTa alloy, MnSi _x O _y and MnO _x , and has one or two layers. It is a layer provided more than a layer.

  Since the barrier material constituting the barrier film itself has a conductive property, the barrier film on the insulating layer must be completely removed in order to prevent an error such as a leakage current. For this removal processing, a method similar to that for polishing the bulk of the metal wiring material can be applied. This is what is called barrier CMP.

  In addition, in the bulk polishing of copper, dishing is likely to occur particularly in a wide metal wiring portion. Therefore, it is desirable that the amount of polishing and removal can be adjusted between the wiring portion and the barrier portion in order to be finally flattened. For this reason, it is desired that the polishing liquid for barrier polishing has an optimal polishing selectivity of copper / barrier metal. 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, peroxodisulfate). There is. The basic mechanism of CMP using such a metal polishing liquid is thought to be that the metal surface is oxidized by an oxidizing agent and the oxide film is removed by abrasive grains for polishing. (For example, refer nonpatent literature 1.).

  Although the metal polishing liquid containing peroxodisulfate as an oxidizing agent has a feature that a high polishing rate can be obtained, there is a problem that dishing and erosion are likely to proceed. As one means for solving dishing, benzotriazoles are used as anticorrosives that suppress polishing of a metal film (see, for example, Patent Document 4). According to such a method, a protective film is formed on the metal film in the semiconductor substrate, and the metal film is left in the concave portion while the convex portion is removed by the abrasive grains, thereby obtaining a desired conductor pattern. Occurrence of dishing is suppressed by the protective film of the recess, and high flatness is obtained.

However, even when these anticorrosives that provide high flatness as described above are used, the occurrence of erosion due to the corrosion of the barrier film cannot be suppressed, and further improvement is required for the flatness necessary for manufacturing the device. It was being done.
US Pat. No. 4,944,836 JP-A-2-278822 JP 49-122432 A JP-A-2005-116987 Journal of Electrochemical Society, 1991, 138, 11, 3460-3464 Journal of Electrochemical Society, 2000, 147, 10, 3907-3913

  The present invention is based on the background that there is a demand for a metal polishing composition for CMP that can realize faster polishing of wiring using copper metal or copper alloy as a raw material in order to increase the productivity of LSI. It was made.

Accordingly, an object of the present invention is to provide a metal polishing composition that is excellent in the polishing rate for a conductor film made of copper or a copper alloy and that can suppress the occurrence of dishing.
Another object of the present invention is to provide a polishing method that is excellent in the polishing rate of a conductor film made of copper or copper metal and that can suppress the occurrence of dishing.

  As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by the following metal polishing composition and a polishing method using the same, and have completed the present invention. That is, the means for solving the problems of the present invention are as follows.

<1> A metal polishing composition comprising the following components and used for chemical mechanical polishing in a manufacturing process of a semiconductor device.
(1) Peroxodisulfate (2A) Anionic surfactant having at least one sulfo group or salt thereof in the molecule (2B) Anionic surfactant having at least one carboxyl group or salt in the molecule (3) Heteroaromatic compounds

  <2> The metal polishing composition according to <1>, further comprising abrasive grains.

  <3> In a semiconductor device manufacturing process, a substrate having a conductor film made of copper or a copper alloy and a barrier film is chemically and mechanically treated using the metal polishing composition according to <1> or <2>. A polishing method characterized by polishing.

ADVANTAGE OF THE INVENTION According to this invention, the composition for metal polishing which is excellent in the grinding | polishing speed | rate with respect to the conductor film which consists of copper or a copper alloy, and can suppress generation | occurrence | production of dishing can be provided.
Moreover, according to this invention, the grinding | polishing method which is excellent in the grinding | polishing speed | rate of the conductor film which consists of copper or copper metal, and can suppress generation | occurrence | production of dishing can be provided.

  Hereinafter, the metal polishing composition of the present invention and the polishing method using the same will be described in detail.

[Metal polishing composition]
The metal polishing composition of the present invention contains the following components, and is used for chemical mechanical polishing in a semiconductor device manufacturing process.
(1) Peroxodisulfate (2A) Anionic surfactant having at least one sulfo group or salt thereof in the molecule (2B) Anionic surfactant having at least one carboxyl group or salt in the molecule (3) Heteroaromatic compounds

  The metal polishing composition of the present invention comprises (1) peroxodisulfate, (2A) an anionic surfactant having at least one sulfo group or salt thereof in the molecule, and (2B) at least one carboxyl in the molecule. By containing each component of an anionic surfactant having a group or a salt thereof, and (3) a heteroaromatic ring compound, a conductor film made of copper or copper metal when CMP is performed in a semiconductor device manufacturing process It has a high polishing rate and exhibits an excellent suppression effect on the occurrence of dishing on the object to be polished.

  One of the features in the present invention is that a specific anionic surfactant is used in combination. Depending on the type of surfactant, there are those that increase the polishing rate, those that are effective in suppressing erosion and dishing, and those that change the selection ratio, but there are few that satisfy all the performance with one type. In the case of a water-based polishing liquid, when surfactants having different charges are used, aggregation tends to occur in the polishing liquid depending on the pH, and it is necessary to select a pH for the combined use. In the metal polishing composition of the present invention, in the metal polishing composition containing a peroxodisulfate salt and a heteroaromatic ring compound, by using a specific anionic surfactant as described above in combination, a surfactant can be used in combination. There is additivity without impairing the effects when used alone, and it is also possible to exert excellent effects on dishing and polishing rate.

  The metal polishing composition of this invention may contain other arbitrary components other than the essential component shown above as needed.

  Each component contained in the metal polishing composition of the present invention may be only one type, or two or more types may be used in combination. Hereinafter, the essential components and optional components contained in the metal polishing composition of the present invention will be described in order.

<(1) Peroxodisulfate>
The metal polishing composition of the present invention contains (1) peroxodisulfate as a compound (oxidizing agent) that can oxidize a metal (copper or copper alloy) that is a suitable polishing target.

  Among the peroxodisulfates, ammonium peroxodisulfate and potassium peroxodisulfate are preferable, and ammonium peroxodisulfate is most preferable from the viewpoint of high polishing rate and low dishing.

  The peroxodisulfate content in the metal polishing composition of the present invention is preferably 0.003 mol to 0.5 mol, preferably 0.03 mol to 0 mol, per liter of the polishing composition when used for polishing. More preferably, the content is 0.2 mol, and particularly preferably 0.1 mol to 0.1 mol. That is, the content of peroxodisulfate that is an oxidizing agent is preferably 0.003 mol or more from the viewpoint of sufficient metal oxidation and ensuring a high CMP rate, and 0.5 mol from the viewpoint of preventing roughening of the polished surface. The following is preferred.

-Other oxidizing agents-
In the present invention, other oxidizing agents can be used in combination with peroxodisulfate. Examples of other oxidizing agents include hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, and heavy chromium Acid salts, permanganates, ozone water, silver (II) salts, iron (III) salts, and the like, and one or more other oxidizing agents can be used in combination with peroxodisulfate. As other oxidizing agents that can be used in combination with peroxodisulfate, hydrogen peroxide, nitrate, iodate, and periodate are preferable, and hydrogen peroxide is particularly preferable.

<(2A) Anionic surfactant having at least one sulfo group or salt thereof in the molecule>
The metal polishing composition of the present invention contains an anionic surfactant having at least one sulfo group or a salt thereof in the molecule (hereinafter, appropriately referred to as “anionic surfactant (A)”) as an essential component. .

  Specific examples of the anionic surfactant (A) in the present invention include alkyl sulfonates (for example, dioctyl sulfosuccinate ester salts), alkyl benzene sulfonic acids (for example, dodecyl benzene sulfonic acid (soft), (hard), ( Branched), ammonium dodecylbenzenesulfonate (soft), (hard), (branched), triethanolamine dodecylbenzenesulfonate, pentadecylbenzenesulfonate, 1/2 calcium salt of dodecylbenzenesulfonate, sodium salt of xylenesulfonate) Alkyl diphenyl ether disulfonate (eg, sodium alkyl diphenyl ether disulfonate), alkyl diphenyl ether monosulfonate (eg, sodium alkyl diphenyl ether monosulfonate), Lunaphthalene sulfonate (eg, monoisopropyl naphthalene sulfonic acid, diisopropyl naphthalene sulfonic acid, ammonium triisopropyl naphthalene sulfonate, sesquibutyl naphthalene sulfonate sodium salt), alkyl sulfosuccinate (eg, sodium dialkyl sulfosuccinate, polyoxyethylene) Lauryl ether sulfosuccinic acid disodium salt, sulfosuccinic acid di-2-ethylhexyl ester sodium salt, dioctyl sulfosuccinic acid sodium salt, dihexyl sulfosuccinic acid sodium salt, dicyclohexylsulfosuccinic acid sodium salt, diamylsulfosuccinic acid sodium salt, ditridecylsulfosuccinic acid sodium salt, Octadecylsulfosuccinamide disodium salt, lauryl disulfosuccinate Thorium salt, polyoxyethylene lauryl ether sulfosuccinic acid half-ester disodium salt, polyoxyethylene alkyl ether sulfosuccinic acid half-ester disodium salt, lauroyl ethanol sulfosuccinic acid amide disodium salt), α-olefin sulfonate, Igepon T (product) Name, IGFARBENINDUSTRIE), Igepon A (trade name, IGFARBENINDUSTRIE), Nekar (trade name, manufactured by BASF), Tamol (trade name, manufactured by BASF), N-acyl sulfonate (for example, palm Oil fatty acid methyl taurine sodium, polyoxyethylene coconut oil aliphatic monoethanolamide sodium sulfate, lauryl methyl tauric acid sodium salt, myristyl methyl tauric acid sodium salt, palmityl methyl tauric acid sodium salt, stearyl methyl tauric acid sodium Thorium salt, tallow oil fatty acid methyl taurate sodium salt), naphthalene and other aromatic sulfonic acid formalin condensates (for example, sodium salt of β-naphthalene sulfonic acid formalin condensate, sodium salt of special aromatic sulfonic acid formalin condensate) , Sodium alkane sulfonate, isethionate, coconut oil fatty acid (coconut oil residues are generally lauryl group, myristyl group, palmityl group, stearyl group) ethyl ester sulfonate sodium salt and the like.

  Among these anionic surfactants that can be used as the anionic surfactant (A), alkylbenzene sulfonic acids, alkyl diphenyl ether sulfonic acid, alkyl diphenyl ether monosulfonic acid, alkyl sulfosuccinic acid, alkyl naphthalene sulfone are used in terms of polishing rate and dishing. Coconut oil fatty acid as acid, α-olefin sulfonate, Igepon T, Igepon A, Necar, Tamol, N-acyl sulfonate, naphthalene and other aromatic sulfonic acid formalin condensate, alkane sulfonic acid sodium salt, isethionate Alkylbenzene sulfonic acids, alkyl diphenyl ether sulfonic acid, alkyl diphenyl ether monosulfonic acid, alkyl sulfosuccinic acid, alkyl naphthalene sulfonic acid, α-o Refin sulfonate, Igepon T, Igepon A, Necar, Tamol, N-acyl sulfonate, naphthalene and other aromatic sulfonic acid formalin condensate, coconut oil fatty acid are more preferable, alkylbenzene sulfonic acids, alkyl diphenyl ether sulfonic acid, alkyl Diphenyl ether monosulfonic acid, alkylsulfosuccinic acid, alkylnaphthalenesulfonic acid, α-olefin sulfonate, Igepon T, Igepon A, Nekar, Tamol, N-acyl sulfonate, and coconut oil fatty acid are more preferable.

  The content of the anionic surfactant (A) in the metal polishing composition of the present invention is 0.00001 g to 10 g per liter of the metal polishing composition when used for polishing in terms of polishing speed and dishing. It is preferable to set it to 0.0002 g to 7 g, and particularly preferably 0.00005 g to 6 g.

<(2B) Anionic surfactant having at least one carboxyl group or salt thereof in the molecule>
The metal polishing composition of the present invention contains an anionic surfactant having at least one carboxyl group or salt thereof in the molecule (hereinafter, appropriately referred to as “anionic surfactant (B)”) as an essential component.

  Examples of the anionic surfactant (B) in the present invention include fatty acid salts (for example, beef tallow fatty acid soda, sodium stearate, potassium oleate, castor oil potash, marcel soap sodium salt, potassium myristate, potassium laurate, lauric acid soap. TEA salt, coconut oil fatty acid soap potassium salt, coconut oil fatty acid soap TEA salt), N-acyl amino acid salt (for example, coconut oil fatty acid sarcosine triethanolamine, coconut oil fatty acid sarcosine sodium salt, lauroyl sarcosine sodium salt, oleoyl sarcosine sodium) Salt), ether carboxylate (for example, polyoxyethylene or polyoxypropylene alkyl ether carboxylate, polyoxyethylene tridecyl ether carboxylate, polyoxyethylene oleyl ether carboxylate) Acylated peptide, polycarboxylic acid type polymer surfactant, alkyl ether carboxylic acid or salt thereof), gum rosin disproportionated rosin soap sodium salt, rosin soap sodium salt, maleic acid modified rosin soap sodium salt, alkenyl succinic acid di (Mono) potassium salt, alanine type surfactant (for example, coconut oil methyl-β-alanine sodium salt, lauroyl-β-alanine sodium salt, myristoyl-β-alanine sodium salt) and the like.

  Among these anionic surfactants that can be used as the anionic surfactant (B), fatty acid salts, N-acyl amino acid salts, acylated peptides, gum rosin-based disproportionated rosin soap sodium salts are preferable in terms of polishing rate and dishing. Rosin soap sodium salt, maleic acid modified rosin soap sodium salt, alkenyl succinic acid di (mono) potassium salt, alanine type surfactant is preferable, fatty acid salt, N-acyl amino acid salt, acylated peptide, gum rosin disproportionation Rosin soap sodium salt, maleic acid-modified rosin soap sodium salt, alkenyl succinic acid di (mono) potassium salt, and alanine type surfactants are more preferred, fatty acid salt, N-acyl amino acid salt, acylated peptide, maleic acid-modified rosin soap Sodium salt, alkenyl succinic acid di (mono) potassium salt Alanine type surfactants are more preferred.

  The content of the anionic surfactant (B) in the metal polishing composition of the present invention is 0.00001 g to 10 g per liter of the metal polishing composition when used for polishing in terms of polishing rate and dishing. It is preferable to set it to 0.0002 g to 7 g, and particularly preferably 0.0005 g to 6 g.

  The content ratio (mass ratio) between the anionic surfactant (A) and the anionic surfactant (B) is 1 part by weight of the anionic surfactant (A). 0.001-1000 mass parts is preferable, 0.005-500 mass parts is more preferable, and 0.01-100 mass parts is further more preferable.

<(2C) Other surfactant>
In addition to the anionic surfactant (A) and the anionic surfactant (B), which are essential components, the metal polishing composition of the present invention includes other anionic surfactants and nonionics listed below as necessary. A surfactant, a cationic surfactant, and an amphoteric surfactant may be contained as optional components. However, among these other surfactants, the cationic surfactant may cause aggregation depending on the pH of the composition. Therefore, in use, a surfactant that does not cause aggregation is appropriately selected according to the design of the composition. There is a need.

  Other anionic surfactants include, for example, sulfate salts such as sulfated oils, alkyl sulfates (for example, sodium lauryl sulfate, higher alcohol sodium sulfate, lauryl sulfate triethanolamine, ammonium lauryl sulfate), alkyl ether sulfates ( For example, polyoxyethylene or polyoxypropylene alkyl ether sulfate (for example, sodium polyoxyethylene lauryl sulfate, polyoxyethylene lauryl ether sulfate triethanolamine), alkylamide sulfate; alkyl phosphate ( For example, potassium octyl phosphate, potassium lauryl phosphate, potassium octyl ether phosphate), polyoxyethylene or polyoxypropylene alkyl allyl ether phosphate For example, polyoxyethylene alkyl phenyl ether phosphoric acid), and the like.

  Examples of the nonionic surfactant include ether type, ether ester type, ester type, and nitrogen-containing type. Specifically, polyoxyalkylene alkyl and polyoxyalkylene alkyl phenyl ether (for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyalkylene alkyl ether) Ethylene higher alcohol ether, polyoxyethylene myristol ether, polyoxyethylene octyldodecyl ether), polyoxyethylene derivatives (for example, polyoxyethylene disulfonated phenyl ether), polyoxyethylene polyoxypropylene glycol, alkylallyl formaldehyde condensed polyoxy Ethylene ether, polyoxyethylene polyoxypropylene block polymer, polyoxyethylene polio Dipropylene alkyl ethers, and the like. As ether ester type, polyoxyethylene ether of glycerin ester, polyoxyethylene fatty acid ester (for example, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyoxyethylene hydrogenated castor oil), polyoxyethylene Sorbitan fatty acid esters (for example, polyoxyethylene sorbitan monococonut oil fatty acid ester, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxy Ethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbate Emissions triisostearate, polyoxyethylene sorbitan mono coconut fatty acid ester, polyoxyethylene sorbit tetraoleate), include polyoxyethylene ethers of sorbitol esters. As ester types, sorbitan fatty acid esters (for example, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan sesquioleate), glycerin fatty acid esters (for example Glycerol monostearate, glycerol monooleate), polyglycerol ester, sorbitan ester, propylene glycol ester, sucrose ester and the like. Examples of the nitrogen-containing type include fatty acid alkanolamide (for example, coconut fatty acid diethanolamide), polyoxyethylene alkylamine (for example, polyoxyethylene laurylamine), polyoxyethylene alkylamide (for example, polyoxyethylene lauric acid amide), and the like. It is done. Moreover, a fluorine-type surfactant, an acetylene containing nonionic surfactant (For example, diisobutyl dimethyl butynediol polyoxyethylene glycol ether) etc. are mentioned.

  Examples of the cationic surfactant include alkylamine salts (for example, coconut amine acetate, stearylamine acetate), quaternary ammonium salts (for example, lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, distearyl). Dimethylammonium chloride, alkylbenzyldimethylammonium chloride), alkylpyridinium salts (for example, cetylpyridinium chloride), and the like.

  Examples of amphoteric surfactants include alkylbetaine type (for example, lauric betaine (lauryldimethylaminoacetic acid betaine, stearylbetaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine), amine oxide type (for example, Lauryl dimethylamine oxide).

The total content of the surfactant in the metal polishing composition of the present invention is preferably 0.00001 g to 10 g, and 0.0002 g to 7 g in 1 L of the metal polishing composition when used for polishing. It is more preferable to make it 0.0005 g to 6 g.
Here, the total content of the surfactant is an essential component in the metal polishing composition of the present invention, an anionic surfactant (A), an anionic surfactant (B), and other optionally used It means the total amount of surfactant.

<(3) Heteroaromatic ring compound>
The metal polishing composition of the present invention contains at least one heteroaromatic ring compound as a compound that forms a passive film on the surface of a metal (copper or copper alloy) to be polished.

  Here, the “heteroaromatic ring compound” is a compound having a heterocycle containing one or more heteroatoms. A hetero atom means an atom other than a carbon atom and a hydrogen atom. A heterocycle means a cyclic compound having at least one heteroatom. A heteroatom means only those atoms that form part of a heterocyclic ring system, either external to the ring system, separated from the ring system by at least one non-conjugated single bond, Atoms that are part of a further substituent of are not meant.

  A hetero atom is preferably a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom, and more preferably a nitrogen atom, a sulfur atom, an oxygen atom, and a selenium atom. And particularly preferably a nitrogen atom, a sulfur atom and an oxygen atom, and most preferably a nitrogen atom and a sulfur atom.

First, the heteroaromatic ring that is the mother nucleus is described.
The number of members of the heterocyclic ring of the heteroaromatic ring compound that can be used in the present invention is not particularly limited, and it may be a monocyclic compound or a polycyclic compound having a condensed ring. The number of members in the case of a single ring is preferably 3 to 8, more preferably 5 to 7, and particularly preferably 5 and 6. The number of rings in the case of having a condensed ring is preferably 2 to 4, more preferably 2 or 3.

Specific examples of these heteroaromatic rings include the following. However, it is not limited to these.
For example, pyrrole ring, thiophene ring, furan ring, pyran ring, thiopyran ring, imidazole ring, pyrazole ring, thiazole ring, isothiazole ring, oxazole ring, isoxazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, pyrrolidine Ring, pyrazolidine ring, imidazolidine ring, isoxazolidine ring, isothiazolidine ring, piperidine ring, piperazine ring, morpholine ring, thiomorpholine ring, chroman ring, thiochroman ring, isochroman ring, isothiochroman ring, indoline ring, isoindoline ring , Pyridine, indolizine, indole, indazole, purine, quinolidine, isoquinoline, quinoline, naphthyridine, phthalazine, quinoxaline, quinazoline, cinnoline, pteridine, Lysine ring, perimidine ring, phenanthroline ring, carbazole ring, carboline ring, phenazine ring, antilysine ring, thiadiazole ring, oxadiazole ring, triazine ring, triazole ring, tetrazole ring, benzimidazole ring, benzoxazole ring, benzothiazole ring Benzothiadiazole ring, benzofuroxan ring, naphthimidazole ring, benzotriazole ring, tetraazaindene ring and the like, more preferably triazole ring and tetrazole ring.

Next, substituents that the heteroaromatic ring may have will be described.
In the present invention, when a specific moiety is referred to as a “group”, the moiety may be unsubstituted or substituted with one or more (up to the maximum possible) substituents. Means good. For example, “alkyl group” means a substituted or unsubstituted alkyl group.

Examples of the substituent that the heteroaromatic ring compound may have include the following. However, it is not limited to these.
For example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched or cyclic alkyl group, and even a polycyclic alkyl group such as a bicycloalkyl group is active. A methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regardless of the position of substitution), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a heterocyclic oxycarbonyl group, a carbamoyl group ( Examples of the carbamoyl group having a substituent include an N-hydroxycarbamoyl group, an N-acylcarbamoyl group, an N-sulfonylcarbamoyl group, an N-carbamoylcarbamoyl group, a thiocarbamoyl group, and an N-sulfamoylcarbamoyl group), a carbazoyl group. , Carboxyl group or salt thereof, oxalyl group, oxy Moyl group, cyano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (including groups containing repeating ethyleneoxy or propyleneoxy group units), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy Or aryloxy) carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, sulfonamido group, ureido group, thioureido group, N-hydroxyureido group, Imido group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfur Nylureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, heterocyclic group containing a quaternized nitrogen atom (for example, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group ), Isocyano group, imino group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group , A sulfo group or a salt thereof, a sulfamoyl group (the sulfamoyl group having a substituent is, for example, an N-acylsulfamoyl group or an N-sulfonylsulfamoyl group) or a salt thereof, a phosphino group, a phosphinyl group, a phosphinyloxy Group, phosphinylamino group, silyl group, etc. It is.

  Here, “active methine group” means a methine group substituted with two electron-attracting groups. “Electron withdrawing group” means, for example, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, trifluoromethyl group, cyano group, nitro group, carvone An imidoyl group is meant. Two electron-withdrawing groups may be bonded to each other to form a cyclic structure. The “salt” means a cation such as alkali metal, alkaline earth metal or heavy metal, or an organic cation such as ammonium ion or phosphonium ion.

Among these, preferable substituents in the heteroaromatic ring compound include, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched or cyclic alkyl group, and bicycloalkyl). A group such as a polycyclic alkyl group or an active methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regarding the position of substitution), an acyl group, an alkoxycarbonyl group, Aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group, N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group, A carbazoyl group, an oxalyl group, an oxamoyl group, Ano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (including groups containing repeating ethyleneoxy group or propyleneoxy group units), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy or aryloxy) ) Carbonyloxy group, carbamoyloxy group, sulfonyloxy group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, sulfonamide group, ureido group, thioureido group, N-hydroxyureido group, imide group, (alkoxy or Aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonylureido group, N- Silureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, quaternized heterocyclic group containing nitrogen atom (for example, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group), isocyano group, imino group Group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or a salt thereof Sulfamoyl group, N-acylsulfamoyl group, N-sulfonylsulfamoyl group or a salt thereof, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, silyl group and the like.
Here, the active methine group means a methine group substituted with two electron-withdrawing groups, and the electron-withdrawing group here means an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkyl group. Examples thereof include a sulfonyl group, an arylsulfonyl group, a sulfamoyl group, a trifluoromethyl group, a cyano group, a nitro group, and a carbonimidoyl group.

  More preferably, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched or cyclic alkyl group, and a polycyclic alkyl group such as a bicycloalkyl group) And may contain an active methine group), an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group (regarding the position of substitution).

  In addition, two of the above-described substituents can be combined to form a ring (aromatic or non-aromatic hydrocarbon ring or heteroaromatic ring), and these can be further combined to form a polycyclic fused ring. Benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring, biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, Pyrimidine ring, pyridazine ring, indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenant Lysine ring, acridine ring, phena Tororin ring, thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, phenazine ring, also form mentioned are) is.

  Specific examples of the heteroaromatic ring compound include, but are not limited to, the following.

  That is, 1,2,3,4-tetrazole, 5-amino-1,2,3,4-tetrazole, 5-methyl-1,2,3,4-tetrazole, 1H-tetrazole-5-acetic acid, 1H- Tetrazole-5-succinic acid, 1,2,3-triazole, 4-amino-1,2,3-triazole, 4,5-diamino-1,2,3-triazole, 4-carboxy-1H-1,2, , 3-triazole, 4,5-dicarboxy-1H-1,2,3-triazole, 1H-1,2,3-triazole-4-acetic acid, 4-carboxy-5-carboxymethyl-1H-1,2 , 3-triazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, 3-carboxy-1,2,4-triazole 3,5-di Rubokishi-1,2,4-triazole, 1,2,4-triazole-3-acetic acid, 1H-benzotriazole, a 1H- benzotriazole-5-carboxylic acid.

  The content of the heteroaromatic ring compound in the metal polishing composition of the present invention is the total amount of the metal polishing composition used for polishing (that is, for metal polishing after dilution when diluted with water or an aqueous solution). Composition) In 1 L, the range of 0.0001 mol to 1.0 mol is preferable, more preferably 0.0005 mol to 0.5 mol, and still more preferably 0.0005 mol to 0.05 mol.

<Organic acid>
The metal polishing composition in the present invention preferably further contains at least one organic acid. The organic acid here is not a metal oxidizing agent, but has an action of promoting oxidation, adjusting pH, and buffering agent.

  The organic acid is preferably water-soluble. Those selected from the following group are more suitable. That is, 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-methyl Hexanoic 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, apple Acid, tartaric acid, citric acid, lactic acid, hydroxyethyliminodiacetic acid, iminodiacetic acid, acedamidoiminodiacetic acid, nitrilotripropanoic acid, nitrilotrimethylphosphonic acid, dihydroxyethylglycine, tricine, and ammonium salts and alkali metals thereof Examples thereof include salts such as salts, ammonium salts, and mixtures thereof.

Moreover, as an amino acid, a water-soluble thing is preferable. As the water-soluble amino acid, those selected from the following group are more suitable.
That is, 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-cysteic acid , L-aspartic acid, L-glutamic acid, S- (carboxymethyl) -L-cysteine, 4-aminobutyric acid 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, Examples include 3-methyl-L-histidine, ergothioneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin II, and antipine.

In the present invention, among the above organic acids or amino acids, the following amino acids are particularly preferably used.
Glycine, iminodiacetic acid, methyliminodiacetic acid, N-methylglycine, nitrilotripropanoic acid, hydroxyethyliminodiacetic acid, L-alanine, β-alanine, glycylglycine, dihydroxyethylglycine, acetamidoiminodiacetic acid, tricine Etc.

  The content of the organic acid is preferably 0.005 mol to 0.5 mol, more preferably 0.01 mol to 0.3 mol in 1 L of the metal polishing composition used for polishing. It is especially preferable to set it as 0.05 mol-0.3 mol. That is, the addition amount of the organic acid is preferably 0.01 mol or more from the viewpoint of improving the polishing rate, and 0.3 mol or less is preferable from the viewpoint of not deteriorating dishing.

  In the metal polishing composition of the present invention, the organic acid may be used alone or in combination of two or more. These organic acids can be synthesized according to a conventional method, or commercially available products may be used.

<Abrasive grains>
The polishing composition of the present invention preferably contains abrasive grains.
Examples of preferable abrasive grains include silica (precipitated silica, fumed silica, colloidal silica, synthetic silica), ceria, alumina, titania, zirconia, germania, manganese oxide, diamond, and the like. Among these, silica, ceria, alumina, titania and the like are preferably used.

  The average particle size (primary particle size) of the abrasive grains contained in the polishing composition of the present invention is preferably in the range of 5 nm to 300 nm, more preferably 10 nm to 200 nm. Particles of 20 nm or more are preferred for the purpose of achieving a sufficient polishing speed. The particle size is preferably 100 nm or less for the purpose of preventing excessive frictional heat during polishing.

  In addition, not only the general inorganic abrasive grains as described above but also organic polymer particles can be used in combination as long as the effects of the present invention are not impaired. In addition, colloidal silica surface-modified with aluminate ions or borate ions, colloidal silica with controlled surface potential, colloidal silica with various surface treatments, composite abrasive grains made of multiple materials, etc. It is also possible to use it accordingly.

The content of the abrasive grains in the metal polishing composition of the present invention is appropriately selected according to the purpose, but generally used in the range of 0 to 30% by mass with respect to the total mass of the metal polishing composition. It is done.
In the present invention, the content of abrasive grains is preferably 20% by mass or less, and more preferably 15% by mass or less from the viewpoint of suppressing scratches caused by abrasive grains.

  Only one type of abrasive grain may be used, or two or more types may be used in combination. It is also possible to use the same type of different sizes or different types of abrasive grains.

<PH of metal polishing composition>
In the metal polishing composition of the present invention, 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 functional group of the compound, the stability as a liquid It is preferable to appropriately set the type, amount of addition, or pH of the above-described components by, for example.

  The pH of the metal polishing composition of the present invention is preferably 3 to 12 and more preferably in the range of 8.0 to 12.0 from the viewpoint of planarization performance. The pH can be easily adjusted by appropriately selecting a buffering agent, an alkaline agent and the like and adding them to the composition.

<Chelating agent>
In the metal polishing composition of the present invention, a chelating agent (that is, a hard water softening agent) can be added as necessary in order to reduce adverse effects such as mixed polyvalent metal ions.

  Chelating agents include general water softeners and related compounds that are calcium and magnesium precipitation inhibitors, such as nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, N, N, N-trimethylenephosphonic acid. , Ethylenediamine-N, N, N ′, N′-tetramethylenesulfonic acid, transcyclohexanediaminetetraacetic acid, 1,2-diaminopropanetetraacetic acid, glycol etherdiaminetetraacetic acid, ethylenediamine orthohydroxyphenylacetic acid, ethylenediamine disuccinic acid ( SS form), N- (2-carboxylateethyl) -L-aspartic acid, β-alanine diacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, N , N′-bis (2-hydroxy Njiru) ethylenediamine -N, N'-diacetic acid, 1,2-dihydroxy-4,6-disulfonic acid.

Two or more chelating agents may be used in combination as necessary.
The content of the chelating agent may be an amount sufficient to sequester metal ions such as mixed multivalent metal ions. For example, in 1 L of a metal polishing composition used for polishing, 0.0003 mol to It adds so that it may become the range of 0.07 mol.

  The metal polishing composition of the present invention described above can be suitably used for the polishing method described in detail below.

[Polishing method]
The polishing method of the present invention comprises chemically and mechanically polishing a substrate having a conductor film made of copper or a copper alloy and a barrier film using the metal polishing composition of the present invention in a semiconductor device manufacturing process. It is characterized by.

  More specifically, in the polishing method of the present invention, the metal polishing composition of the present invention is supplied to a polishing pad on a polishing platen, and the polishing plate is rotated to rotate the polishing pad. It is a chemical mechanical polishing method characterized in that polishing is carried out by making a relative movement while contacting a surface to be polished of (a substrate having a conductor film and a barrier film). Hereinafter, this chemical mechanical polishing method will be described in detail.

(Polishing equipment)
First, an apparatus capable of carrying out the polishing method of the present invention will be described.
As a polishing apparatus applicable to the present invention, a holder for holding an object to be polished (semiconductor substrate or the like) having a surface to be polished and a polishing pad are attached (a motor or the like whose rotation speed can be changed is attached). A general polishing apparatus provided with a polishing surface plate can be used. For example, FREX300 (Ebara Seisakusho) can be used.

(Polishing pressure)
In the polishing method of the present invention, polishing is preferably performed at a polishing pressure, that is, a contact pressure between the surface to be polished and the polishing pad in the range of 3000 Pa to 25000 Pa, and more preferably in the range of 6500 Pa to 14000 Pa. .

(Number of rotations of polishing surface plate)
In the polishing method of the present invention, polishing is preferably performed at a rotation speed of the polishing platen of 500 rpm to 200 rpm, more preferably 60 rpm to 150 rpm.

(Polishing liquid supply method)
In the present invention, a metal polishing composition (polishing liquid, the same applies hereinafter) is continuously supplied by a pump or the like to a polishing pad on a polishing surface plate while polishing the target metal. Although there is no restriction | limiting in this supply amount, it is preferable that the surface of a polishing pad is always covered with polishing liquid.

  In the polishing method of the present invention, water or an aqueous solution can be added to a concentrated polishing liquid for dilution. As a dilution method, for example, a method of supplying a concentrated polishing liquid to a polishing pad by joining and mixing a pipe for supplying a concentrated polishing liquid and a pipe for supplying water or an aqueous solution together in the middle. Can be mentioned. In this case, mixing is a method in which liquids collide with each other through a narrow passage with pressure applied, a method in which a filling such as a glass tube is filled in the piping, a flow of liquid is separated and separated, and piping is repeated. Conventional methods such as a method of providing blades that rotate with power can be used.

Further, as another dilution method, a pipe for supplying a polishing liquid and a pipe for supplying water or an aqueous solution are provided independently, and a predetermined amount of liquid is supplied from each to the polishing pad, and the polishing pad and the surface to be polished are provided. A method of mixing by relative motion can also be used in the present invention.
Further, a method in which a predetermined amount of concentrated polishing liquid and water or an aqueous solution are mixed in one container, mixed and diluted to a predetermined concentration, and then the mixed liquid is supplied to the polishing pad is also applicable to the present invention. be able to.

  In addition to these methods, a method in which the component to be contained in the polishing liquid is divided into at least two components, and when these are used, water or an aqueous solution is added and diluted to be supplied to the polishing pad is also used in the present invention. be able to. In this case, it is preferable to divide and supply the component containing an oxidizing agent and the component containing the organic acid in the present invention.

  Specifically, the oxidizing agent is preferably one component (A), and the organic acid, additive, surfactant, heterocyclic compound, abrasive grains, and water are preferably one component (B). When using them, the component (A) and the component (B) are diluted with water or an aqueous solution. In this case, three pipes for supplying the component (A), the component (B), and water or an aqueous solution are necessary, and the three pipes are connected to one pipe for supplying the polishing pad, The two pipes may be combined and then another one pipe may be combined and mixed. For example, a component containing a hard-to-dissolve additive is mixed with other components, and the mixing path is lengthened to ensure a dissolution time, and then a polishing liquid is supplied by further coupling a water or aqueous solution pipe. It is also possible.

  Further, the above three pipes may be led to the polishing pad and mixed and supplied by the relative movement of the polishing pad and the surface to be polished. After mixing the three components in one container, the mixed solution is supplied. You may supply to a polishing pad. Further, the metal polishing composition may be used as a concentrate, and the diluted water may be separately supplied to the polishing surface.

(Abrasive supply amount)
In the polishing method of the present invention, the supply amount of the polishing liquid onto the polishing surface plate is preferably 50 ml / min to 500 ml / min, and more preferably 100 ml / min to 300 ml / min.

(Polishing pad)
The polishing pad used in the polishing method of the present invention is not particularly limited, and 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.

  The polishing pad in the present invention may further contain abrasive grains (for example, ceria, silica, alumina, resin, etc.) used for polishing. In addition, each has a softness and a hardness, and either of them 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. Further, the surface that contacts the polished surface may be subjected to processing such as lattice grooves / holes / concentric grooves / helical grooves.

  Next, an object to be polished (substrate, wafer) to be polished in the polishing method of the present invention will be described.

(Wiring metal material)
The object to be polished in the present invention is preferably a substrate (wafer) having wiring made of copper or a copper alloy. As the wiring metal material, a copper alloy containing silver is suitable among the copper alloys. The silver content contained in the copper alloy exhibits an excellent effect at 10% by mass or less, further 1% by mass or less, and the most excellent effect in the copper alloy in the range of 0.00001 to 0.1% by mass. Demonstrate.

(Wiring thickness)
In the DRAM device system, for example, the object to be polished in the present invention preferably has a wiring with a half pitch, preferably 0.15 μm or less, more preferably 0.10 μm or less, and further preferably 0.08 μm or less.
On the other hand, the MPU device system preferably has a wiring of preferably 0.12 μm or less, more preferably 0.09 μm or less, and still more preferably 0.07 μm or less.
The polishing liquid used in the present invention exhibits a particularly excellent effect on the object to be polished having such wiring.

(Barrier layer)
In the object to be polished in the present invention, a barrier layer for preventing copper diffusion is provided between a wiring (a conductor film made of copper or a copper alloy) and an insulating film (including an interlayer insulating film). As the barrier metal material constituting the barrier layer, a low-resistance metal material such as TiN, TiW, Ta, TaN, W, or WN is preferable, and Ta or TaN is particularly preferable.

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

[Examples 1 to 10, Comparative Examples 1 to 5]
As the metal polishing compositions (polishing liquids) of Examples 1 to 10 and Comparative Examples 1 to 5, polishing liquids 101 to 110 and polishing liquids 201 to 205 were prepared, and polishing tests and evaluations were performed.

(Preparation of metal polishing composition)
The following compositions were mixed to prepare polishing liquids 101 to 110 and polishing liquids 201 to 205 which are metal polishing compositions.

-Composition of metal polishing composition-
-Anionic surfactant (A) or comparative surfactant-Types and contents shown in Table 1-Anionic surfactant (B) or comparative surfactant-Types and contents shown in Table 1-Abrasive grains: Table 1 10g / L of abrasive grains shown in
Organic acid: compounds shown in Table 1 5 g / L
・ Heterocyclic compound: benzotriazole 0.5 g / L
-Oxidizing agent The kind shown in Table 1 and content Pure water was added to make the total amount 1000 ml, and each was a metal polishing composition of PH 9.5.

(Polishing test)
Polishing was performed under the following conditions, and the polishing rate and dishing were evaluated.
・ Polishing equipment: FREX300 (Ebara Works)
-Object to be polished (wafer):
(1) For polishing rate calculation; a 1.5 μm thick Cu film was formed on a silicon substrate
300 mm diameter blanket wafer (2) For dishing evaluation; 300 mm diameter copper wiring wafer (pattern wafer)
(Mask pattern 754CMP (ATDF))
Polishing pad: IC1400-K Groove (Rodel)
・ Polishing conditions;
Polishing pressure (contact pressure between the surface to be polished and the polishing pad): 10.5 kPa
Polishing liquid supply rate: 200 ml / min
Polishing platen rotation speed: 104rpm
Polishing head rotation speed: 105 rpm (Processing linear velocity: 1.0 m / sec)

(Evaluation methods)
1) Polishing rate The polishing rate is calculated by polishing the blanket wafer of (1) for 60 seconds, and converting the metal film thickness before and after polishing from the electrical resistance value for 49 equally spaced locations on the wafer surface. The average value of the values obtained and divided by the polishing time was taken as the polishing rate.
2) Dishing The evaluation of dishing was performed on the pattern wafer of (2) above, in addition to the time until the copper in the non-wiring portion was completely polished, and further polishing by 25% of the time. The step of the and space part (line 10 μm, space 10 μm) was measured with a contact-type step gauge Dektak V3201 (manufactured by Veeco).
The results are shown in Table 1.

  The combinations shown in Table 1 as surfactants (1) and (2) are combinations of surfactants A and B in the present invention, or combinations of two surfactants that are outside the scope of the present invention. Show.

  As is apparent from Table 1, each of the polishing liquids of Examples containing two combinations of surfactants A and B, peroxodisulfate as an oxidizing agent, and a heteroaromatic ring compound is a chemical mechanical polishing method. It was found that when applied to (the polishing method of the present invention), both a high polishing rate and low dishing can be achieved. On the other hand, the comparative polishing liquid containing only one of surfactants A and B is difficult to achieve both high polishing rate and low dishing, and even when the amount of surfactant is increased, the polishing rate decreases. Or the dishing only worsened.

[Example 11]
In Example 1, a polishing liquid 111 was prepared in the same manner as in Example 1 except that 0.002 g / L of glycerol monostearate as a nonionic surfactant was further added. When polishing was performed in the same manner as in Example 1 using the obtained polishing liquid 111, dishing was equivalent to that in Example 1, and a polishing rate of 670 nm / min was obtained.

[Comparative Examples 6 and 7]
A polishing liquid 206 of Comparative Example 6 was obtained in the same manner as in Example 11 except that the coconut oil fatty acid sarcosine triethanolamine was not used in Example 11.
In Example 11, a polishing liquid 207 of Comparative Example 7 was prepared in the same manner as Example 11 except that dodecylbenzenesulfonic acid was not used.
Using the obtained polishing liquids 206 and 207, the same polishing as in Example 11 was performed, and the polishing speed and dishing were compared with the polishing liquid 111 of Example 11. As a result, the polishing liquid 206 had a polishing speed of It decreased to 320 nm / min, and with respect to the polishing liquid 207, the dishing deteriorated to 89 nm.

  From the results of Example 11 and Comparative Examples 6 and 7, it is understood that a high polishing rate and a low dishing can be achieved only when both the surfactants A and B are present.

[Example 12]
A polishing liquid 112 was prepared in the same manner as in Example 1 except that 0.001 g / L of beef fatty acid soda was further added as the surfactant A in Example 1, and the same evaluation as in Example 1 was performed. As a result, the polishing rate was 542 nm / min and the dishing was 17 nm.

[Comparative Example 8]
A polishing liquid 208 was prepared in the same manner as in Example 1 except that the oxidizing agent was changed to hydrogen peroxide (10 g / L) in Example 1, and the same polishing as in Example 1 was performed. As a result, the polishing rate was as low as 421 nm / min and the dishing was 156 nm.
This result shows that a high polishing rate and low dishing can be obtained for the first time when peroxodisulfate and surfactants A and B are used as oxidizing agents.

Claims (3)

A metal polishing composition comprising the following components and used for chemical mechanical polishing in a semiconductor device manufacturing process.
(1) Peroxodisulfate (2A) Anionic surfactant having at least one sulfo group or salt thereof in the molecule (2B) Anionic surfactant having at least one carboxyl group or salt in the molecule (3) Heteroaromatic compounds   Furthermore, an abrasive is contained, The metal polishing composition of Claim 1 characterized by the above-mentioned.   In a manufacturing process of a semiconductor device, a substrate having a conductor film made of copper or a copper alloy and a barrier film is chemically and mechanically polished using the metal polishing composition according to claim 1 or 2. A polishing method characterized by the above.