JP2014165318A - Polishing composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing composition suitable for polishing of a material including a precious metal or tantalum and capable of increasing through-put.SOLUTION: A polishing composition includes a polishing accelerator and a pH adjuster. The polishing accelerator is a compound having an amino group, a cyano group and a sulfur atom. The sulfur atom includes a compound having a bond with hydrogen, carbon or metal.

Description

  The present invention relates to a polishing composition, and more particularly to a polishing composition suitable for polishing noble metals or tantalum.

  In recent years, new microfabrication techniques have been developed along with higher integration and higher performance of LSIs. Chemical mechanical polishing (hereinafter also simply referred to as CMP) is one of them, and is frequently used in LSI manufacturing processes, particularly in the formation of interlayer insulating films, metal plugs, and embedded wiring (damascene wiring) in the multilayer wiring forming process. The technology used. This technique is disclosed in Patent Document 1, for example. Damascene wiring technology can simplify the wiring process and improve yield and reliability, and its application is expected to expand in the future.

  In high-speed logic devices, copper is mainly used as a wiring metal because of its low resistance as damascene wiring. Copper is expected to be used in memory devices such as DRAMs in the future. . A general method of metal CMP is to apply a polishing pad on a circular polishing platen (platen), immerse the surface of the polishing pad with an abrasive and press the surface on which the metal film of the substrate is formed. In this state, the polishing platen is rotated in a state in which the pressure (hereinafter also simply referred to as polishing pressure) is applied, and the metal film on the convex portion is removed by mechanical friction between the abrasive and the convex portion of the metal film.

  On the other hand, tantalum, a tantalum alloy, a tantalum compound, or the like is formed as a barrier layer in a lower layer such as copper or copper alloy of the wiring to prevent copper diffusion into the interlayer insulating film. Therefore, it is necessary to remove the exposed barrier layer by CMP except for the wiring portion in which copper or a copper alloy is embedded. However, since the barrier layer is generally harder than copper or copper alloy, CMP using a combination of polishing materials for copper or copper alloy often does not provide a sufficient CMP rate.

  On the other hand, tantalum, tantalum alloy, or tantalum compound used as a barrier layer is chemically stable and difficult to etch, and has high hardness, so mechanical polishing is not as easy as copper or copper alloy. In recent years, noble metal materials such as ruthenium, ruthenium alloys, and ruthenium compounds have been studied as materials for the barrier layer. Precious metal materials such as ruthenium, ruthenium alloys, and ruthenium compounds have a lower resistivity than tantalum, tantalum alloys, or tantalum compounds, and can be deposited by chemical vapor deposition (CVD) for thinner wiring. It is excellent in that it can be handled. However, noble metal materials such as ruthenium, ruthenium alloys, and ruthenium compounds are difficult to polish because they are chemically stable and high in hardness, like tantalum, tantalum alloys, or tantalum compounds.

The noble metal material is used as an electrode material in a manufacturing process of a DRAM capacitor structure, for example. Then, polishing using a polishing composition is used to remove part of a portion made of a material containing a noble metal such as ruthenium simple substance or ruthenium oxide (RuO _x ). However, similar to the aforementioned noble metal materials for the barrier layer, removal of the chemically stable noble metal-containing material is generally time consuming, and this type of polishing composition further increases throughput. There is a strong need for improvement.

  Abrasives used in CMP generally include an oxidizer and abrasive grains. It is believed that the basic mechanism of CMP by this CMP abrasive is that the surface of the metal film is first oxidized by an oxidizing agent, and the resulting oxide layer on the surface of the metal film is scraped off by abrasive grains. Since the oxide layer on the surface of the metal film in the concave portion does not touch the polishing pad so much and the effect of scraping off by the abrasive grains is not exerted, the metal film on the convex portion is removed and the substrate surface is flattened as CMP proceeds.

  In CMP, a high polishing rate with respect to a wiring metal, stability of the polishing rate, and a low defect density on the polishing surface are required. However, since the film containing ruthenium is chemically more stable and harder than other damascene wiring metal films such as copper and tungsten, an oxide film is formed with an oxidant and removed mechanically. It is difficult to obtain a high throughput by the conventional polishing method. For example, in Patent Document 2, as a polishing agent for a tantalum-based metal film used for a barrier layer of a copper wiring, as a polishing accelerator for a copper-based metal film in addition to abrasive grains, ammonium nitrate as an oxidizing agent, and water, A polishing slurry containing 2,4-triazole is disclosed.

  Patent Document 3 discloses a method of forming an oxide film functioning as an etching barrier on the surface of copper or copper alloy with an oxidizing agent and then etching copper or copper alloy with aminoacetic acid.

U.S. Pat. No. 4,944,836 JP 2004-259867 A JP 2002-43260 A

  However, the polishing agent described in Patent Document 2 or 3 has not yet achieved a sufficient throughput, and cannot be an effective polishing method for noble metals or tantalum.

  Therefore, an object of the present invention is to provide a polishing composition which is suitable for polishing a material containing a noble metal or tantalum and can improve the throughput.

  In order to solve the above-mentioned problems, the present inventors have intensively studied. As a result, a polishing accelerator and a pH adjuster are included, and the polishing accelerator is a compound having an amino group or a cyano group and a sulfur atom, and the sulfur atom is bonded to hydrogen, carbon, or a metal. It has been found that the above-mentioned problems can be solved by using a polishing composition containing a compound having the following. And based on the said knowledge, it came to complete this invention.

  That is, the present invention includes a polishing accelerator and a pH adjuster, and the polishing accelerator is a compound having an amino group or a cyano group and a sulfur atom, and the sulfur atom is hydrogen, carbon, or a metal. It is polishing composition containing the compound which has a coupling | bonding.

  ADVANTAGE OF THE INVENTION According to this invention, it is suitable for grinding | polishing the material containing a noble metal or a tantalum, and the polishing composition which can improve a throughput can be provided.

It is a section schematic diagram showing an example of the polish subject concerning the present invention. It is a graph at the time of evaluating the corrosion potential about the reference examples 1-4 by the Tafel plot method.

  The present invention includes a polishing accelerator and a pH adjuster, wherein the polishing accelerator is a compound having an amino group or a cyano group and a sulfur atom, and the sulfur atom is hydrogen, carbon, or a metal. It is polishing composition containing the compound which has a coupling | bonding. With such a configuration, the polishing rate of a material containing noble metal or tantalum is improved, and high throughput can be achieved.

  Although the detailed reason why the polishing rate of the material containing noble metal or tantalum is improved by using the polishing composition of the present invention is unknown, the following mechanism is assumed. The sulfur atom contained in the polishing accelerator acts as a soft base because of its high covalent bond, and can form a strong bond with a noble metal or a late metal such as tantalum, particularly ruthenium. In addition, since the polishing accelerator contains a nitrogen atom having a high electron donating property, the nucleophilicity of the sulfur atom is increased, whereby the polishing accelerator is more easily coordinated to a noble metal such as ruthenium or tantalum (polishing). Accelerators are susceptible to oxidation). By this coordination, the metal-metal bond of noble metal or tantalum is weakened, the noble metal or tantalum can be efficiently scraped off by the abrasive grains, and the generated complex has an amino group or the like. Therefore, it is considered that the throughput is improved. In addition, the said mechanism is based on estimation and this invention is not limited to the said mechanism at all.

[Polishing object]
An example of a polishing object and a semiconductor wiring process according to the present invention will be described with reference to FIG. The semiconductor wiring process usually includes the following steps.

  As shown in FIG. 1A, a barrier layer 13 and a metal wiring layer 14 are sequentially formed on an insulator layer 12 having a trench 11 provided on a substrate (not shown). In the present invention, the barrier layer 13 contains a noble metal or tantalum. Prior to the formation of the metal wiring layer 14, the barrier layer 13 is formed on the insulator layer 12 so as to cover the surface of the insulator layer 12. The thickness of the barrier layer 13 is smaller than the depth and width of the trench 11. Following the formation of the barrier layer 13, the metal wiring layer 14 is formed on the barrier layer 13 so that at least the trench 11 is filled.

  When removing at least the outer portion of the metal wiring layer 14 and the outer portion of the barrier layer 13 by CMP, first, most of the outer portion of the metal wiring layer 14 is removed as shown in FIG. Next, as shown in FIG. 1C, the remainder of the outer portion of the metal wiring layer 14 is removed to expose the upper surface of the outer portion of the barrier layer 13.

  Thereafter, at least a portion of the metal wiring layer 14 located outside the trench 11 (outside portion of the metal wiring layer 14) and a portion of the barrier layer 13 located outside the trench 11 (outside portion of the barrier layer 13) are obtained by CMP. Remove. As a result, as shown in FIG. 1D, at least a part of the portion of the barrier layer 13 located in the trench 11 (inner portion of the barrier layer 13) and the metal wiring layer 14 located in the trench 11. At least a part of the portion (the inner portion of the metal wiring layer 14) remains on the insulator layer 12. That is, a part of the barrier layer 13 and a part of the metal wiring layer 14 remain inside the trench 11. Thus, the portion of the metal wiring layer 14 remaining inside the trench 11 functions as a wiring.

  The polishing composition of the present invention is particularly suitable for polishing a polishing object having a layer containing a noble metal or tantalum as described above.

  The noble metal contained in the layer containing noble metal or tantalum such as the barrier layer 13 and capacitor electrode material in FIG. 1 is not particularly limited, and examples thereof include gold, silver, platinum, palladium, rhodium, ruthenium, iridium, osmium and the like. It is done.

  These noble metals or tantalum may be contained in a layer containing the noble metal or tantalum in the form of an alloy or a compound. Ruthenium, silver, gold, palladium, platinum, rhodium, iridium, osmium and tantalum are preferable. These noble metals or tantalum may be used alone or in combination of two or more.

  Moreover, the metal contained in the metal wiring layer 14 is not particularly limited, and examples thereof include copper, aluminum, hafnium, cobalt, nickel, titanium, and tungsten. These metals may be contained in the metal wiring layer 14 in the form of an alloy or a metal compound. Copper or copper alloy is preferable. These metals may be used alone or in combination of two or more.

  Next, the structure of the polishing composition of the present invention will be described in detail.

[Polishing accelerator]
The polishing accelerator used in the present invention is a compound having an amino group or a cyano group and a sulfur atom, and the sulfur atom essentially contains a compound having a bond with hydrogen, carbon, or a metal. These polishing accelerators may be used alone or in combination of two or more.

Examples of the compound having these characteristics include a compound having an amino group (—NH ₂ group) and a thiol group (—SH group), a compound having a thioamide group, and a compound having a thiocyano group.

Examples of the compound having an amino group (—NH ₂ group) and a thiol group (—SH group) include, for example, 2-aminoethanethiol, L-cysteine, homocysteine, D-penicylamine, 2-mercaptobenzeneamine, 2 -Amino-1,3,4-thiadiazole-5-thiol, 3-amino-1H-1,2,4-triazole-5-thiol, 1-aminoethanethiol, selenodimercaptoethylamine, bis (mercaptomethyl) amine Cysteamine hydrochloride, monoethanolamine thioglycolate, (mercaptocarbonyl) methanamine, N- (2,2-dimethyl-4,6-dioxo-1,3-dioxane-5-ylidenemercaptomethyl) -N-methyl Amine, 2-mercapto-p-phenylenediamine, 12-mercaptododeca -1,1-diamine, 2,7-dimercapto-1,8-octanediamine, 1- (2-pyridinyl) -3-[(2-mercaptoethyl) thio] -1H-1,2,4-triazole- 5-amine, N- (2-mercaptopropyl) trimethylenediamine, 4,5,6,7-tetrahydro-5-[(2-mercaptophenyl) sulfonyl] thiazolo [5,4-c] pyridin-2-amine Bis (2-aminoethyl) 2-[(2-mercapto-1,2-dimethylpropyl) amino] ethylamine, 5-[(6-mercaptobenzothiazol-2-yl) azo] quinolin-8-amine, N , N′-bis [2-mercapto-3- (aminomethyl) -5-tert-butylbenzyl] -1,3-propanediamine, 5- (2-furyl) -3-mercapto- H-1,2,4-triazol-4-amine, N, N-bis (2-mercaptoethyl) -1,1′-biphenyl-4,4′-diamine, 2-mercaptobenzylamine, 9- (10 -Mercaptodecyl) -9H-purin-6-amine, N- (1,2-dimethyl-2-mercaptopropylidene) -N '-(2-aminoethyl) ethylenediamine, O- (3-mercaptopropyl) hydroxylamine N- [3- (benzylamino) propyl] -3-mercapto-1,4-butanediamine, N- (2-mercaptophenethyl) -1,3,5-triazine-2,4-diamine, 5- ( 4-methoxyphenyl) -3-mercapto-4H-1,2,4-triazol-4-amine, 5- (4-bromophenyl) -3-mercapto-4H-1,2,4-tri Azole-4-amine, 5- [4- (5-mercaptopentyloxy) benzylideneamino] pyrimidine-2,4,6-triamine, 3-amino-1-propanethiol, 3,3′-bismethylmercaptobenzidine, 2-amino-4,6-dimercaptopyrimidine, mercaptophosphoranylideneaminoaminophosphine sulfide, thiocytosine, 4-amino-5-ethyl-4H-1,2,4-triazole-3-thiol, 11-amino-1 -Undecanethiol, 5-amino-1,3,4-thiadiazole-2-thiol, 4-amino-4H-1,2,4-triazole-3-thiol, 16-aminohexadecane-1-thiol, 4-amino- 5-methyl-4H-1,2,4-triazole-3-thiol, 3- [2- [bis (2-amino Noethyl) amino] ethylimino] -2-methyl-2-butanethiol, 2,5-diamino-1,4-benzenedithiol, sulfenamide, 4,6-diaminopyrimidine-2-thiol, 5-bromo-2- Aminobenzenethiol, 4-amino-5-phenyl, 2,5-diamino-1,4-benzenedithiol, sulfenamide, 4,6-diaminopyrimidine-2-thiol, 5-bromo-2-aminobenzenethiol, 4-amino-benzenethiol, 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol, 3-amino-1H-1,2,4-triazole-5-thiol, 4-amino -5- (3-pyridinyl) -4H-1,2,4-triazole-3-thiol, 2-[(3-aminopropyl) amino] ethane -1-thiol, 2-amino-1-propanethiol, 4-amino-5-[(2-methoxyphenoxy) methyl] -4H-1,2,4-triazole-3-thiol, 2-amino-5 Methylbenzenethiol, propamine, 1,4-diamino-2,3-benzenedithiol, 1-aminoethanethiol, 2,6-diaminopyridine-4-thiol, 4-amino-4H-1,2,4-triazole- 3,5-dithiol, 2-amino-5-chlorobenzenethiol, 4-amino-5- (2-methylphenyl) -4H-1,2,4-triazole-3-thiol, 4-amino-5- (4 -Methyl-2-quinolyloxymethyl) -4H-1,2,4-triazole-3-thiol, 4-amino-5- (4-chlorophenyl) -4H-1,2,4 Triazole-3-thiol, and the like. Of these, 2-aminoethanethiol, L-cysteine, homocysteine, and D-penicylamine are preferable.

  Examples of the compound having a thioamide group include thioacetamide, (dimethylamino) acetothioamide, thiosemicarbazide, dithioxamide, ambazone, 3-ethoxy-1,2-butanedione bis (thiosemicarbazone), and 1-methyl. -3-thiosemicarbazonoindoline-2-one, dithiobiurea, dithiobiuret, thiobenzamide, 5-nitrothioanthranilic acid, 1-phenylthiosemicarbazide, pyrazinecarbothioamide, pyridine-4-carbothioamide, 4-hydroxybenzaldehyde thiosemi Carbazone, 4-nitrobenzaldehyde thiosemicarbazone, benzaldehyde thiosemicarbazone, 4-methoxybenzaldehyde thiosemicarbazone, tilaldehyde thiosemicarbazone, isonicotine Oamide 1-oxide, 3-cyclohexene-1-carbothioamide, 2,4-dichlorobenzothioamide, thioformamide, 2-methylcyclohexanone thiosemicarbazone, benzenethioacetamide, pyridine-3-carbothioamide, 2-aminothiobenzamide 2,2-dimethylpropanethioamide, propanethioamide, 2-chlorobenzaldehyde thiosemicarbazone, 4-chlorobenzaldehyde thiosemicarbazone, 2,6-pyridinedicarbothioamide, 6-methyl-2-pyridinecarbothioamide, 2 , 4-dimethylthiosemicarbazide, pyridine-2-carbothioamide, 1-methyl-2- (1-methylethylidene) hydrazinecarbothioamide, 2-methylthiosemicarbazide and the like. Of these, thioacetamide is preferable.

  Furthermore, examples of the compound having a thiocyano group include sodium thiocyanate, thiocyanate, guanidine thiocyanate, thiamine thiocyanate, erythromycin thiocyanate, allyl isothiocyanate, heptyl isothiocyanate, ethyl rhodanate, ethylthio Cyanate, 1-naphthyl isothiocyanate, allyl thiocyanate, 4-fluorophenyl isothiocyanate, ammonium thiocyanate, methyl isothiocyanate, potassium thiocyanate, barium thiocyanate, isothiocyanate, phenyl isothiocyanate, isobutyl Isothiocyanate, bisthiocyanatomercury (II), calcium thiocyanate, cyclohexyl isothiocyanate, ethyl isothiocyanate, phenethylisothio Anato, silver thiocyanate, cadmium thiocyanate, copper (I) thiocyanate, lead (II) bisthiocyanate, lithium thiocyanate, nickel (II) thiocyanate, zinc thiocyanate, mercuric thiocyanate, mercury mercury thiocyanate (II) etc. are mentioned. Of these, sodium thiocyanate is preferable.

  The polishing composition of the present invention may further include a polishing accelerator other than the compound having the specific structure described above. As the polishing accelerator other than the compound having the above specific structure, conventionally known compounds can be used. For example, inorganic acids, organic acids, amino acids, nitrile compounds, chelating agents, and the like can be used. Specific examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, phosphoric acid and the like. Specific examples of organic acids include 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, malein Examples include acid, phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid. Organic sulfuric acids such as methanesulfonic acid, ethanesulfonic acid and isethionic acid can also be used. A salt such as an alkali metal salt of an inorganic acid or an organic acid may be used instead of the inorganic acid or the organic acid or in combination with the inorganic acid or the organic acid.

Specific examples of amino acids include glycine, α-alanine, β-alanine, N-methylglycine, N, N-dimethylglycine, 2-aminobutyric acid, norvaline, valine, leucine, norleucine, isoleucine, phenylalanine, proline, sarcosine, Ornithine, lysine, taurine, serine, threonine, homoserine, tyrosine, bicine, tricine, 3,
5-diiodo-tyrosine, β- (3,4-dihydroxyphenyl) -alanine, thyroxine, 4-hydroxy-proline, cysteine, methionine, ethionine, lanthionine,
Cystathionine, cystine, cysteic acid, aspartic acid, glutamic acid, S- (carboxymethyl) -cysteine, 4-aminobutyric acid, asparagine, glutamine, azaserine, arginine, canavanine, citrulline, δ-hydroxy-lysine, creatine, histidine, 1- Examples include methyl-histidine, 3-methyl-histidine, and tryptophan. Of these, glycine, alanine, malic acid, tartaric acid, citric acid, glycolic acid, isethionic acid or salts thereof are preferred.

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

Specific examples of chelating agents include 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 ether diamine tetraacetic 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-hydroxybenzyl) ethylenediamine-N, N′-diacetic acid, 1,2-
And dihydroxybenzene-4,6-disulfonic acid.

  The lower limit of the content (concentration) of the polishing accelerator in the polishing composition of the present invention is not particularly limited because it exhibits an effect even in a small amount, but is 0.0001 M (mol / L) or more. Preferably, it is 0.0005M (mol / L) or more, more preferably 0.001M (mol / L) or more. The upper limit of the content (concentration) of the polishing accelerator in the polishing composition of the present invention is preferably 10 M (mol / L) or less, more preferably 5 M (mol / L) or less. More preferably, it is 1 M (mol / L) or less. If it is this range, the effect of this invention can be acquired more efficiently. And it is preferable that a polishing accelerator contains the compound which has the specific structure mentioned above as a main component, Specifically, Content of the compound which has the specific structure mentioned above which occupies 100 mass% of the whole quantity of a polishing accelerator. Is preferably 50% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100% by mass.

[PH adjuster]
The pH adjuster used in the polishing composition of the present invention may be either acid or alkali, and may be either an inorganic compound or an organic compound. Specific examples of the acid include inorganic acids such as sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid and phosphoric acid; formic acid, acetic acid, propionic acid, butyric acid, 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, glycol Acids, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid and lactic acid and other carboxylic acids, and methanesulfonic acid, And organic acids such as organic sulfuric acid such as ethanesulfonic acid and isethionic acid. Specific examples of the alkali include ammonia, amines such as ethylenediamine and piperazine, and quaternary ammonium salts such as tetramethylammonium and tetraethylammonium. These pH regulators can be used alone or in combination of two or more.

  The pH of the polishing composition of the present invention is adjusted by the pH adjusting agent. The lower limit of the pH of the polishing composition of the present invention is not particularly limited, but from the viewpoint of safety, it is preferably 1 or more, preferably 1.5 or more, and more preferably 2 or more. . Further, the upper limit of the pH of the polishing composition of the present invention is not particularly limited, but is preferably 12 or less, preferably 11.5 or less, and 11 or less in order to prevent dissolution of abrasive grains. Is more preferable.

[Other ingredients]
The polishing composition of the present invention is water, abrasive grains, complexing agent, metal anticorrosive, antiseptic, antifungal agent, oxidizing agent, reducing agent, polymer, surfactant, sparingly soluble as necessary. Other components such as an organic solvent for dissolving the organic substance may be further included. Hereinafter, preferable other components, such as water, abrasive grains, metal anticorrosive, oxidizing agent, preservative, and antifungal agent, will be described.

[water]
The polishing composition of the present invention may contain water as a dispersion medium or solvent for dispersing or dissolving each component. From the viewpoint of suppressing the inhibition of the action of other components, water containing as little impurities as possible is preferable. Specifically, after removing impurity ions with an ion exchange resin, pure water from which foreign matters are removed through a filter is used. Water, ultrapure water, or distilled water is preferred.

[Abrasive]
The polishing composition of the present invention may contain abrasive grains. The abrasive has an action of mechanically polishing the object to be polished, and improves the polishing rate of the object to be polished by the polishing composition.

  The abrasive used may be any of inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of the inorganic particles include particles made of metal oxides such as silica, alumina, ceria, titania, silicon nitride particles, silicon carbide particles, and boron nitride particles. Specific examples of the organic particles include polymethyl methacrylate (PMMA) particles. These abrasive grains may be used alone or in combination of two or more. The abrasive grains may be commercially available products or synthetic products.

  Among these abrasive grains, silica is preferable, and colloidal silica is particularly preferable. The abrasive grains may be surface modified.

  The lower limit of the average primary particle diameter of the abrasive grains is preferably 5 nm or more, more preferably 7 nm or more, and further preferably 10 nm or more. Further, the upper limit of the average primary particle diameter of the abrasive grains is preferably 500 nm or less, more preferably 100 nm or less, and further preferably 70 nm or less. Within such a range, the polishing rate of the object to be polished by the polishing composition is improved, and the occurrence of dishing on the surface of the object to be polished after polishing with the polishing composition is further suppressed. Can do. In addition, the average primary particle diameter of an abrasive grain is calculated based on the specific surface area of the abrasive grain measured by BET method, for example.

  The lower limit of the content of abrasive grains in the polishing composition is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, with respect to 100% by mass of the total amount of the composition. The content is more preferably 0.1% by weight or more, and most preferably 1% by weight or more. Further, the upper limit of the content of the abrasive grains in the polishing composition is preferably 50% by weight or less, more preferably 30% by weight or less, with respect to 100% by mass of the total amount of the composition. More preferably, it is not more than% by weight. Within such a range, the polishing speed of the object to be polished can be improved, and the cost of the polishing composition can be reduced, and the surface of the object to be polished after being polished with the polishing composition is scratched. Can be further suppressed.

[Metal anticorrosive]
The polishing composition of the present invention may contain a metal anticorrosive. By adding a metal anticorrosive to the polishing composition, it is possible to further suppress the formation of a dent on the side of the wiring in the polishing using the polishing composition. Moreover, it can suppress more that dishing arises on the surface of the grinding | polishing target object after grind | polishing using a polishing composition.

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

  Specific examples of heterocyclic compounds that can be used as metal anticorrosives include, for example, pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, pyridine compounds, pyrazine compounds, pyridazine compounds, pyridine compounds, indolizine compounds, indoles. Compound, isoindole compound, indazole compound, purine compound, quinolidine compound, quinoline compound, isoquinoline compound, naphthyridine compound, phthalazine compound, quinoxaline compound, quinazoline compound, cinnoline compound, buteridine compound, thiazole compound, isothiazole compound, oxazole compound, iso Examples thereof include nitrogen-containing heterocyclic compounds such as oxazole compounds and furazane compounds.

  More specific examples include pyrazole compounds such as 1H-pyrazole, 4-nitro-3-pyrazolecarboxylic acid, 3,5-pyrazolecarboxylic acid, 3-amino-5-phenylpyrazole, 5 -Amino-3-phenylpyrazole, 3,4,5-tribromopyrazole, 3-aminopyrazole, 3,5-dimethylpyrazole, 3,5-dimethyl-1-hydroxymethylpyrazole, 3-methylpyrazole, 1-methyl Pyrazole, 3-amino-5-methylpyrazole, 4-amino-pyrazolo [3,4-d] pyrimidine, allopurinol, 4-chloro-1H-pyrazolo [3,4-D] pyrimidine, 3,4-dihydroxy-6 -Methylpyrazolo (3,4-B) -pyridine, 6-methyl-1H-pyrazolo [3,4-b] pyridine - amine.

  Examples of imidazole compounds include, for example, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1,2-dimethylpyrazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, benzimidazole, 5,6-dimethylbenzimidazole, 2-aminobenzimidazole, 2-chlorobenzimidazole, 2-methylbenzimidazole, 2- (1-hydroxyethyl) benzimidazole, 2-hydroxybenzimidazole, 2-phenylbenzimidazole, 2 , 5-dimethylbenzimidazole, 5-methylbenzimidazole, 5-nitrobenzimidazole, 1H-purine and the like.

  Examples of triazole compounds include, for example, 1,2,3-triazole, 1,2,4-triazole, 1-methyl-1,2,4-triazole, methyl-1H-1,2,4-triazole-3. -Carboxylate, 1,2,4-triazole-3-carboxylic acid, methyl 1,2,4-triazole-3-carboxylate, 1H-1,2,4-triazole-3-thiol, 3,5-diamino -1H-1,2,4-triazole, 3-amino-1,2,4-triazole-5-thiol, 3-amino-1H-1,2,4-triazole, 3-amino-5-benzyl-4H -1,2,4-triazole, 3-amino-5-methyl-4H-1,2,4-triazole, 3-nitro-1,2,4-triazole, 3-bromo-5-nitro-1, , 4-tri Sol, 4- (1,2,4-triazol-1-yl) phenol, 4-amino-1,2,4-triazole, 4-amino-3,5-dipropyl-4H-1,2,4-triazole 4-amino-3,5-dimethyl-4H-1,2,4-triazole, 4-amino-3,5-dipeptyl-4H-1,2,4-triazole, 5-methyl-1,2,4 -Triazole-3,4-diamine, 1H-benzotriazole, 1-hydroxybenzotriazole, 1-aminobenzotriazole, 1-carboxybenzotriazole, 5-chloro-1H-benzotriazole, 5-nitro-1H-benzotriazole, 5-carboxy-1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazo 1- (1 ′, 2′-dicarboxyethyl) benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl ] -5-methylbenzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] -4-methylbenzotriazole, and the like.

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

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

  Examples of indole compounds include 1H-indole, 1-methyl-1H-indole, 2-methyl-1H-indole, 3-methyl-1H-indole, 4-methyl-1H-indole, 5-methyl-1H- Indole, 6-methyl-1H-indole, 7-methyl-1H-indole, 4-amino-1H-indole, 5-amino-1H-indole, 6-amino-1H-indole, 7-amino-1H-indole, 4-hydroxy-1H-indole, 5-hydroxy-1H-indole, 6-hydroxy-1H-indole, 7-hydroxy-1H-indole, 4-methoxy-1H-indole, 5-methoxy-1H-indole, 6- Methoxy-1H-indole, 7-methoxy-1H-indole, 4-chloro-1H- Ndole, 5-chloro-1H-indole, 6-chloro-1H-indole, 7-chloro-1H-indole, 4-carboxy-1H-indole, 5-carboxy-1H-indole, 6-carboxy-1H-indole, 7-carboxy-1H-indole, 4-nitro-1H-indole, 5-nitro-1H-indole, 6-nitro-1H-indole, 7-nitro-1H-indole, 4-nitrile-1H-indole, 5- Nitrile-1H-indole, 6-nitrile-1H-indole, 7-nitrile-1H-indole, 2,5-dimethyl-1H-indole, 1,2-dimethyl-1H-indole, 1,3-dimethyl-1H- Indole, 2,3-dimethyl-1H-indole, 5-amino-2,3-dimethyl-1H- Ndole, 7-ethyl-1H-indole, 5- (aminomethyl) indole, 2-methyl-5-amino-1H-indole, 3-hydroxymethyl-1H-indole, 6-isopropyl-1H-indole, 5-chloro -2-methyl-1H-indole and the like.

  Among these, preferred heterocyclic compounds are triazole compounds, and in particular, 1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole, 1- [N, N-bis (hydroxy Ethyl) aminomethyl] -5-methylbenzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] -4-methylbenzotriazole, 1,2,3-triazole, and 1,2,4-triazole Is preferred. Since these heterocyclic compounds have high chemical or physical adsorptive power to the surface of the object to be polished, a stronger protective film can be formed on the surface of the object to be polished. This is advantageous in improving the flatness of the surface of the object to be polished after polishing using the polishing composition of the present invention.

  Further, the surfactant used as the metal anticorrosive may be any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

  Examples of anionic surfactants include, for example, polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl sulfuric acid ester, alkyl sulfuric acid ester, polyoxyethylene alkyl ether sulfuric acid, alkyl ether sulfuric acid, alkylbenzene sulfonic acid, alkyl phosphoric acid ester , Polyoxyethylene alkyl phosphate ester, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthalene sulfonic acid, alkyl diphenyl ether disulfonic acid, and salts thereof.

  Examples of the cationic surfactant include alkyl trimethyl ammonium salt, alkyl dimethyl ammonium salt, alkyl benzyl dimethyl ammonium salt, alkyl amine salt and the like.

  Examples of amphoteric surfactants include alkyl betaines and alkyl amine oxides.

  Examples of nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, and alkyl alkanolamide. Is mentioned.

  Among these, preferable surfactants are polyoxyethylene alkyl ether acetate, polyoxyethylene alkyl ether sulfate, alkyl ether sulfate, alkylbenzene sulfonate, and polyoxyethylene alkyl ether. Since these surfactants have a high chemical or physical adsorption force to the surface of the object to be polished, a stronger protective film can be formed on the surface of the object to be polished. This is advantageous in improving the flatness of the surface of the object to be polished after polishing using the polishing composition of the present invention.

  The lower limit of the content of the metal anticorrosive in the polishing composition is preferably 0.001 g / L or more, more preferably 0.005 g / L or more, and 0.01 g / L or more. Is more preferable. Further, the upper limit of the content of the metal anticorrosive in the polishing composition is preferably 50 g / L or less, more preferably 25 g / L or less, and further preferably 5 g / L or less. Within such a range, the surface flatness of the polishing object after polishing with the polishing composition can be improved, and the polishing rate of the polishing object with the polishing composition can be maintained. .

〔Oxidant〕
The polishing composition of the present invention may contain an oxidizing agent. Specific examples of the oxidizing agent include hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, perchloric acid; persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate. These oxidizing agents may be used alone or in combination of two or more.

  Among them, persulfate and hydrogen peroxide are preferable, and hydrogen peroxide is particularly preferable.

  The lower limit of the content (concentration) of the oxidizing agent in the polishing composition is preferably 0.001 M (mol / l) or more, more preferably 0.005 M (mol / l) or more, 0 More preferably, it is 0.01 M (mol / l) or more. There is an advantage that the polishing rate by the polishing composition is improved as the content of the oxidizing agent is increased.

  In addition, the upper limit of the content (concentration) of the oxidizing agent in the polishing composition is preferably 50 M (mol / l) or less, more preferably 25 M (mol / l) or less, and 10 M (mol). / L) More preferably, it is less than or equal to. As the content of the oxidizing agent decreases, the material cost of the polishing composition can be reduced, and the processing of the polishing composition after polishing, that is, the advantage of reducing the load of waste liquid treatment can be achieved. Have. In addition, there is an advantage that excessive oxidation of the surface of the object to be polished by the oxidizing agent hardly occurs.

[Preservatives and fungicides]
Examples of the antiseptic and fungicide used in the present invention include isothiazoline-based antiseptics such as 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, Paraoxybenzoates, phenoxyethanol and the like can be mentioned. These antiseptics and fungicides may be used alone or in combination of two or more.

[Method for producing polishing composition]
The method for producing the polishing composition of the present invention is not particularly limited. For example, the polishing accelerator, the pH adjuster, and other components as necessary are stirred and mixed in a solvent or dispersion medium such as water. Can be obtained.

  Although the temperature at the time of mixing each component is not specifically limited, 10-40 degreeC is preferable and you may heat in order to raise a dissolution rate. Further, the mixing time is not particularly limited.

[Polishing method and substrate manufacturing method]
As described above, the polishing composition of the present invention is suitably used for polishing a polishing object having a layer containing a noble metal or tantalum. Therefore, this invention provides the grinding | polishing method which grind | polishes the grinding | polishing target object which has a layer containing a noble metal or a tantalum with the polishing composition of this invention. Moreover, this invention provides the manufacturing method of a board | substrate including the process of grind | polishing the grinding | polishing target object which has a layer containing a noble metal or a tantalum with the said grinding | polishing method.

  As a polishing apparatus, a general holder having a polishing surface plate on which a holder for holding a substrate having a polishing object and a motor capable of changing the number of rotations are attached and a polishing pad (polishing cloth) can be attached. A polishing apparatus can be used.

  As the polishing pad, a general nonwoven fabric, polyurethane, porous fluororesin, or the like can be used without particular limitation. It is preferable that the polishing pad is grooved so that the polishing liquid accumulates.

  The polishing conditions are not particularly limited, and for example, the rotation speed of the polishing platen is preferably 10 to 500 rpm, and the pressure (polishing pressure) applied to the substrate having the object to be polished is preferably 0.5 to 10 psi. The method of supplying the polishing composition to the polishing pad is not particularly limited, and for example, a method of continuously supplying with a pump or the like is employed. Although the supply amount is not limited, it is preferable that the surface of the polishing pad is always covered with the polishing composition of the present invention.

  After the polishing is completed, the substrate is washed in running water, and water droplets adhering to the substrate are removed by a spin dryer or the like and dried to obtain a substrate having a layer containing a noble metal or tantalum.

  The present invention will be described in further detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

(Reference Examples 1 to 11)
The corrosion potential was measured by Tafel plot method using a polishing accelerator as shown in Table 1. As a sample solution, a solution obtained by adding sodium sulfate to a polishing accelerator 0.01 M aqueous solution and adjusting the electric conductivity to 10 mS / cm was used. The apparatus and measurement conditions used are as shown in Table 1 below.

  The evaluation results are shown in Table 2 below and FIG. In Table 2 below, ○ in the corrosion potential column indicates that the corrosion potential is lower than that in Reference Example 3, and × indicates that the corrosion potential is not different from that in Reference Example 3. FIG. 2 is a graph when the corrosion potentials of Reference Examples 1 to 4 are evaluated.

As is clear from Table 2 and FIG. 2, it can be seen that the corrosion potential of Ru is lowered by adding the compounds having the amino group (—NH ₂ group) and thiol group (—SH group) of Reference Examples 1 and 2. . Therefore, it is suggested that the noble metal is easily oxidized by the compounds of Reference Examples 1 and 2.

(Examples 1-6, Comparative Examples 1-6)
As shown in Table 2, the polishing accelerator is 0.01M (mol / l), nitric acid or potassium hydroxide as the pH adjuster, hydrogen peroxide is 0.2M (mol / l) as the oxidizing agent, and the abrasive grains Colloidal silica having an average primary particle size of 35 nm and an average secondary particle size of 68 nm is stirred and mixed in water at an addition amount of 10% by weight with respect to 100% by mass of the total composition (mixing temperature: about 25 ° C., Mixing time: about 10 minutes), polishing compositions of Examples 1 to 6 and Comparative Examples 1 to 6 were prepared. The pH of the composition was confirmed with a pH meter. The average primary particle size is calculated from the surface area measurement measured by the BET method, and the average secondary particle size is measured by a dynamic light scattering type particle size measuring device.

Using the obtained polishing composition, the polishing rate when the surface of the ruthenium (Ru) wafer was polished under the polishing conditions shown in Table 3 below was measured. The polishing rate was determined by dividing the difference in Ru wafer thickness before and after polishing measured by using a sheet resistance measuring instrument based on the DC 4 probe method by the polishing time. Further, with respect to the used polishing accelerator, the corrosion potential was measured by the Tafel plot method under the conditions shown in Table 1 above. The evaluation results are shown in Table 4 below. The evaluation criteria for the corrosion potential are the same as in Table 2.

As is apparent from Table 4, an amino group or cyano group, such as a compound having an amino group (—NH ₂ group) and a thiol group (—SH group), a compound having a thioamide group, or a compound having a thiocyano group, and sulfur The polishing rate of a polishing composition containing a polishing accelerator, which is a compound having an atom and the sulfur atom has a bond with hydrogen, carbon, or metal, is higher than that of the polishing composition of the comparative example. I understood that. Therefore, the compound having an amino group or a cyano group and a sulfur atom according to the present invention, wherein the sulfur atom has a bond with hydrogen, carbon, or a metal, is a polishing of a noble metal such as ruthenium or tantalum. It turns out that it has the effect of increasing the rate.

11 Trench,
12 Insulating layer,
13 Barrier layer (layer containing noble metal or tantalum),
14 Metal wiring layer.

Claims (5)

A polishing accelerator;
a pH adjuster,
The polishing composition, wherein the polishing accelerator is a compound having an amino group or a cyano group and a sulfur atom, and the sulfur atom includes a compound having a bond with hydrogen, carbon, or a metal.   The polishing composition according to claim 1, which is used for polishing a polishing object having a layer containing a noble metal or tantalum.   The polishing composition according to claim 2, wherein the noble metal is at least one selected from the group consisting of gold, silver, platinum, palladium, rhodium, ruthenium, iridium, and osmium.   The grinding | polishing method which grind | polishes the grinding | polishing target object which has a layer containing a noble metal or a tantalum with the polishing composition of any one of Claims 1-3.   The manufacturing method of a board | substrate including the process of grind | polishing the grinding | polishing target object which has a layer containing a noble metal or a tantalum with the grinding | polishing method of Claim 4.