JP2013089819A - Composition for grinding, grinding method using the same, and method for manufacturing substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding composition suitable for grinding of noble metal, and an application thereof.SOLUTION: The grinding composition of the invention is used in application in grinding an object to be polished which has a noble metal-containing barrier layer and a metal wiring layer. The grinding composition comprises grinding grains, a certain oxidant and water. The oxidant has the structure of a peroxy group (-O-O-) with oxygen substituted with one material selected from ammonium, alkali metals, and alkali-earth metals. The grinding composition optionally includes one or both of a grinding accelerator and a protection-film-forming agent. The grinding accelerator has the effect of keeping or increasing the speed of grinding the noble metal-containing barrier layer. The protection-film-forming agent never suppresses the speed of grinding the noble metal-containing barrier layer.

Description

  The present invention relates to a polishing composition suitable for polishing noble metals and use thereof.

  In recent years, new microfabrication techniques have been developed along with higher integration and higher performance of LSIs. The chemical mechanical polishing (hereinafter referred to as CMP) method is one of them, and is frequently used in the LSI manufacturing process, especially in the multilayer wiring formation process, flattening of interlayer insulation film, metal plug formation, and embedded wiring (damascene wiring) formation. Technology. This technique is disclosed in Patent Document 1, for example. Damascene wiring technology can simplify the wiring process, improve yield and reliability, and its application is expected to expand in the future.

  As damascene wiring, copper is mainly used as a wiring metal for high-speed logic devices because of its low resistance. In addition, the use is expected to be expanded to memory devices represented by 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 where the pressure (hereinafter 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 to prevent copper diffusion into the interlayer insulating film under the copper or copper alloy of the wiring. Therefore, it is necessary to remove the exposed barrier layer by CMP except for the wiring portion in which copper or copper alloy is embedded. However, since the barrier layer conductor film generally has a higher hardness than copper or a copper alloy, a sufficient CMP rate cannot often be obtained by a combination of polishing materials for copper or copper alloy.

  On the other hand, tantalum, tantalum alloy, tantalum compound, and the like used as the barrier layer are chemically stable and difficult to etch, and have high hardness, so mechanical polishing is not as easy as copper and copper alloy. In recent years, ruthenium, ruthenium alloys, and ruthenium compounds have been studied as materials for the barrier layer. Ruthenium, a ruthenium alloy, and a ruthenium compound are superior in that they have a lower resistivity than tantalum, a tantalum alloy, and a tantalum compound, can be formed by chemical vapor deposition (CVD), and can handle narrow wiring. However, ruthenium, ruthenium alloys, and ruthenium compounds are difficult to polish because they are chemically stable and have high hardness like tantalum, tantalum alloys, and tantalum compounds.

  The polishing agent used in CMP is generally composed of an oxidizing agent and abrasive grains. The basic mechanism of CMP by this CMP polishing agent is to first oxidize the surface of the metal film with the oxidizing agent, It is considered to be scraped off with 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 with the progress of CMP.

  In CMP, a high polishing rate for a wiring metal, polishing rate stability, and a low defect density on a polishing surface are required. However, ruthenium films are chemically stable and harder than other damascene wiring metal films such as copper and tungsten, and are therefore difficult to polish. As such a noble metal, especially ruthenium film polishing polishing liquid, for example, a polishing liquid as shown in Patent Document 2 has been proposed. However, since removal of chemically stable noble metal oxides generally takes time, there is a strong need for further improvements to improve throughput for this type of polishing composition.

U.S. Pat. No. 4,944,836 JP 2004-172326 A

  Accordingly, an object of the present invention is to provide a polishing composition having a high removal rate with respect to an object to be polished having a barrier layer containing a noble metal and a metal wiring layer, particularly a barrier layer containing a noble metal, and a polishing method and substrate using the same. It is to provide a manufacturing method.

  As a result of intensive studies, the inventors of the present invention have a high removal rate with respect to a polishing object having a barrier layer containing a noble metal and a metal wiring layer, particularly a barrier layer containing a noble metal, by including abrasive grains and a specific oxidizing agent. The polishing composition which has this was discovered.

That is, the gist of the present invention is as follows.
<1> A polishing composition used for polishing a polishing object having a barrier layer containing a noble metal and a metal wiring layer, comprising abrasive grains, an oxidizing agent, water, and optionally a polishing accelerator and a protective film. And / or the oxidizing agent has a structure in which any one selected from ammonium, alkali metal, and alkaline earth metal is substituted on oxygen of a peroxy group (—O—O—). A polishing composition characterized by the above.
<2> The oxidizing agent is any one or more selected from ammonium salts, alkali metal salts, and alkaline earth metal salts of peroxomonosulfuric acid.
<3> Further contains a polishing accelerator.
<4> The polishing accelerator has an effect of maintaining or improving the polishing rate of the barrier layer containing the noble metal.
<5> Further contains a protective film forming agent.
<6> The protective film forming agent does not maintain or suppress the polishing rate of the barrier layer containing the noble metal.
<7> The noble metal is ruthenium.
<8> A polishing method comprising polishing the surface of a polishing object having a barrier layer containing a noble metal and a metal wiring layer, using the polishing composition according to any one of <1> to <7>.
<9> Using the polishing composition according to any one of <1> to <8>, a barrier layer containing a noble metal and a metal wiring layer to obtain a substrate containing a barrier layer containing a noble metal and a metal wiring layer A method for producing a substrate having a barrier layer containing a noble metal, comprising removing a part of the barrier layer containing a noble metal by polishing a surface of an object to be polished.

  According to the present invention, a polishing object having a barrier layer containing a noble metal and a metal wiring layer, particularly a polishing composition having a high removal rate with respect to a barrier layer containing a noble metal, and a polishing method and substrate using the same. A method is provided.

Embodiments of the present invention will be described below.
The polishing composition of the present embodiment is prepared by mixing abrasive grains and a specific oxidizing agent in water and adding a pH adjuster as necessary to adjust the pH to a desired value. Therefore, the polishing composition of the present embodiment contains abrasive grains, a specific oxidizing agent and water, and further contains a pH adjuster as necessary. This polishing composition is used for polishing noble metal, more specifically, by polishing a surface of an object to be polished having a barrier layer containing a noble metal and a metal wiring layer to remove a part of the barrier layer portion containing the noble metal. Used in the production of a substrate having a barrier layer containing a noble metal. The noble metal generally corresponds to silver, gold, palladium, platinum, rhodium, iridium, ruthenium, and osmium. Therefore, the polishing composition of the present embodiment is used for polishing these noble metals. Especially, it uses suitably for the use which grind | polishes the barrier layer containing palladium, platinum, rhodium, iridium, ruthenium, or osmium, especially the use which grind | polishes the barrier layer containing ruthenium.

(Oxidant)
The oxidizing agent contained in the polishing composition has a structure in which any one selected from ammonium, alkali metal, and alkaline earth metal is substituted on oxygen of a peroxy group (—O—O—) (hereinafter, “ A specific oxidant). For example, ruthenium can be oxidized to the +2, +3, +4, +6, +7, and +8 oxidation states (eg, M. Pourbaix,
Atlas of Electrochemical Equilibria in Aqueous Solutions, 343-349 (Pergamon Press
1966)). Common oxidation forms are Ru ₂ O ₃ , ie, Ru (OH) ₃ and RuO ₂ , where ruthenium is oxidized to the +3 and +4 oxidation states, respectively. +4 oxidation of ruthenium to the oxidation state, i.e. formation of RuO ₂ results in the formation of a protective layer to the surface of the ruthenium, also +3 ruthenium oxide in the oxidation state, i.e. Ru (OH) ₃ formation, the protective Resulting in unintended layers. Therefore, in any state, it is considered that mechanical removal with the abrasive grains is possible, and ruthenium can be oxidized into +3 and +4 oxidation states by using the oxidizing agent under the above conditions. Examples of the oxidizing agent having a structure in which any one selected from ammonium, alkali metal, and alkaline earth metal is substituted on oxygen of the peroxy group (—O—O—) include, for example, peroxypropionic acid (CH ₃ CH ₂ C (═O) —O—OH), diperoxysuccinic acid (HO—O—C (═O) CH ₂ CH ₂ —C (═O) —O—OH), perbenzoic acid (C ₆ H) ₁₁ C (═O) —O—OH), cyclohexaneperoxycarboxylic acid (cyclo-C ₆ H ₁₁ C (═O) —O—OH), monoperoxyhexanedioic acid (HO—C (═O) — (CH _{2) 4 -C (= O)} -O-OH), mono peroxy terephthalate _{(HO-C (= O)} -C 6 H 4 -C (= O) -O-OH), cyclohexane monoperoxyphthalate -1, 4-dicarboxylic acid (HO-C _{= O) -C 6 H 10 -C} (= O) -O-OH), peracetic acid _{(CH 3 -C (= O)} -O-OH), peroxo transient chlorate (HO-O-Cl (= _O) 3), peroxo monophosphate _{((HO) 2 -PO-O} -OH), peroxomonosulfuric carbonate (HO-C (= O) -O-OH) and peroxomonosulfuric acid _(HO-SO 2 -O- And a salt in which the H group at the terminal of (OH) is substituted with an ammonium salt, an alkali metal salt, or an alkaline earth metal. These are preferably selected from alone or a combination thereof, and preferably contain at least one oxidizing agent. Among them, preferably, it is at least one selected from ammonium salt, alkali metal salt, and alkaline earth metal salt of peroxomonosulfuric acid (HO—SO ₂ —O—OH), and most preferably potassium salt of peroxomonosulfuric acid ( _HO-SO 2 _-O-OK) is.

  The upper limit of the content of the oxidizing agent in the polishing composition is preferably 3% by mass, more preferably 2% by mass, and still more preferably 1% by mass. As the content of the oxidizing agent decreases, the polishing rate of the metal wiring layer can be suppressed and defects such as dishing can be suppressed.

  The lower limit of the content of the oxidizing agent in the polishing composition is preferably 0.001% by mass, more preferably 0.01% by mass, and still more preferably 0.1% by mass. As the content of the oxidizing agent increases, the polishing rate improves.

(Abrasive grains)
The polishing composition contains abrasive grains. The abrasive grains 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, and silicon nitride particles, silicon carbide particles, and boron nitride particles. Specific examples of the organic particles include polymethyl methacrylate (PMMA) particles. Among these, silica particles are preferable, and colloidal silica is particularly preferable.

  The abrasive grains may be surface-modified. Since ordinary colloidal silica has a zeta potential value close to zero under acidic conditions, silica particles are not electrically repelled with each other under acidic conditions and are likely to agglomerate. On the other hand, abrasive grains whose surfaces are modified so that the zeta potential has a relatively large positive or negative value even under acidic conditions are strongly repelled and dispersed well even under acidic conditions. This will improve the storage stability. Such surface-modified abrasive grains are, for example, doped with metal such as aluminum, titanium or zirconium or their oxides and mixed with the abrasive grains, or by sulfonic acid groups or phosphonic acid groups, It can be obtained by modifying the surface of the abrasive grains using a silane coupling agent having an amino group.

  The content of abrasive grains in the polishing composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1% by mass or more. As the content of the abrasive grains increases, there is an advantage that the removal rate of the object to be polished by the polishing composition is improved.

  The content of abrasive grains in the polishing composition is also preferably 25% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less. As the content of the abrasive grains decreases, the material cost of the polishing composition can be reduced, and in addition, aggregation of the abrasive grains hardly occurs. Moreover, it is easy to obtain a polished surface with few surface defects by polishing an object to be polished using the polishing composition.

  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. As the average primary particle diameter of the abrasive grains increases, there is an advantage that the removal rate of the object to be polished by the polishing composition is improved. In addition, the value of the average primary particle diameter of an abrasive grain can be calculated based on the specific surface area of the abrasive grain measured by BET method, for example.

  The average primary particle diameter of the abrasive grains is also preferably 100 nm or less, more preferably 90 nm or less, and still more preferably 80 nm or less. As the average primary particle diameter of the abrasive grains decreases, it is easy to obtain a polished surface with few surface defects by polishing the object to be polished using the polishing composition.

  The average secondary particle diameter of the abrasive grains is preferably 150 nm or less, more preferably 120 nm or less, and still more preferably 100 nm or less. As the value of the average secondary particle diameter of the abrasive grains, for example, a volume average particle diameter obtained by a laser light scattering method can be used.

  The average degree of association of the abrasive grains obtained by dividing the value of the average secondary particle diameter of the abrasive grains by the value of the average primary particle diameter is preferably 1.2 or more, more preferably 1.5 or more. . There is an advantage that the removal rate of the object to be polished by the polishing composition is improved as the average degree of association of the abrasive grains increases.

  The average degree of association of the abrasive grains is also preferably 4 or less, more preferably 3 or less, and still more preferably 2 or less. As the average degree of association of the abrasive grains decreases, it is easy to obtain a polished surface with few surface defects by polishing the object to be polished using the polishing composition.

(Inorganic and organic salts)
The polishing composition can further contain one or more selected from inorganic salts and organic salts, in addition to the abrasive grains and the specific oxidizing agent. When the inorganic salt and the organic salt are used together with the specific oxidizing agent in the present embodiment, the stability of the specific oxidizing agent can be maintained or improved. Although the kind of inorganic salt and organic salt is not particularly limited, specific examples of the anion constituting the inorganic salt and organic salt include a sulfate group, a phosphate group, a nitrate group, and a chloride. On the other hand, specific examples of the cations that form a pair with these anions include ammonium salts, alkali metal salts, and alkaline earth metals. These inorganic salts and organic salts are selected from alone or a combination thereof, and preferably contain at least one or more inorganic salts and organic salts. Moreover, you may provide in the form which comprised the specific oxidizing agent and double salt of this embodiment. Among these, Preferably it is 1 or more chosen from potassium chloride, potassium sulfate, and potassium hydrogen sulfate.

  The upper limit of the content of the inorganic salt and organic salt in the polishing composition is not particularly limited, but is preferably 0.05 mol / L, more preferably 0.03 mol / L, still more preferably 0.01 mol / L. As the content of the inorganic salt and the organic salt decreases, the cost of the material for the polishing composition can be reduced, which is preferable.

  The lower limit of the content of the inorganic salt and organic salt in the polishing composition is not particularly limited, but is preferably 0.00001 mol / L, more preferably 0.0001 mol / L, still more preferably 0.001 mol / L. As the content of inorganic salt and organic salt increases, the stability of a specific oxidizing agent contained in the polishing composition is improved, which is preferable.

(Polishing accelerator)
The polishing composition can optionally further contain a polishing accelerator in addition to the abrasive grains and the specific oxidizing agent. If the polishing accelerator is, for example, a complexing agent, it has a function of chemically etching the surface of the barrier layer containing the noble metal, and functions to improve the polishing rate by the polishing composition. However, when used together with the specific oxidizing agent in this embodiment, the polishing accelerator must have an effect of maintaining or improving the polishing rate of the barrier layer containing the noble metal. That is, it should not be a substance that impairs the stability of the oxidizing agent, and a polishing accelerator that does not inhibit the oxidizing action of the oxidizing agent on the barrier layer containing the noble metal should be selected. Examples of such a polishing accelerator include inorganic acids, organic acids and their salts, and organic solvents that do not have a chelating action. Specific examples of the inorganic acid having no chelate structure include hydrochloric acid, nitric acid, sulfuric acid, boric acid, carbonic acid, phosphoric acid, hypophosphorous acid, phosphorous acid, and salts thereof. Examples of organic acids having no chelating activity 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-methyl Pentanoic 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 , Carboxylic acids such as pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid and lactic acid, and organic sulfuric acids such as methanesulfonic acid, ethanesulfonic acid and isethionic acid. Moreover, as an organic solvent, what can be mixed with water arbitrarily is preferable. For example, carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; lactones such as butyrolactone and propyrolactone; ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, and the like Glycol, glycol monoether glycol, diether; ethers such as tetrahydrofuran, dioxane, dimethoxyethane, polyethylene oxide, ethylene glycol monomethyl acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate; methanol, ethanol, propanol, n-butanol, n- Alcohols such as butanol, n-hexanol, isopropanol; ketones such as acetone and methyl ethyl ketone; carboxylic acid esters such as ethyl acetate and ethyl lactate; other acetonitrile, dimethyl sulfoxide, phenol, dimethylformamide, formaldehyde, n-methylpyrrolidone, sulfolane, etc. Can be mentioned.

These are preferably selected from a single or a combination thereof and contain at least one polishing accelerator. Among these, potassium carbonate, isethionic acid, formic acid, acetonitrile, formaldehyde or a salt thereof is preferable.

  The upper limit of the content of the polishing accelerator in the polishing composition is not particularly limited, but is preferably 50% by mass, more preferably 10% by mass, and further preferably 1% by mass. As the polishing accelerator content decreases, defect effects such as dishing of the metal wiring layer can be improved.

  The lower limit of the content of the polishing accelerator in the polishing composition is not particularly limited, but is preferably 0.001% by mass, more preferably 0.01% by mass, and still more preferably 0.1% by mass. . As the content of the polishing accelerator is increased, the polishing rate is improved.

(Protective film forming agent)
The polishing composition can further contain a protective film forming agent in addition to the abrasive grains and the specific oxidizing agent. The protective film forming agent here is a substance having an action of forming a protective film on the surface of the metal wiring layer (see, for example, JP-A-2005-150757). However, when used together with the specific oxidizing agent in this embodiment, the protective film forming agent forms a protective film on the surface of the metal wiring layer while maintaining or suppressing the polishing rate of the barrier layer containing the noble metal. It must be a substance that has the action of That is, it should not be a substance that impairs the stability of the oxidant, and a protective film forming agent that does not inhibit the oxidant's oxidation action on the barrier layer containing the noble metal should be selected. As such a protective film forming agent, for example, a protective film forming agent which does not have a structure exhibiting a chelating action and does not have a —N═N— bond can be mentioned. For example, alkylamines such as ammonia, dimethylamine, trimethylamine, triethylamine, propylenediamine, amines such as ethylenediaminetetraacetic acid (hereinafter abbreviated as EDTA), sodium diethyldithiocarbamate and chitosan, 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-proli , L-cysteine, 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, L-asparagine, L-glutamine, azaserine, L-arginine, L-canavanine, L-citrulline, δ-hydroxy-L-lysine, creatine, L-quinurenin, L-histidine, 1-methyl- Amino acids such as L-histidine, 3-methyl-L-histidine, ergothioneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin II and antipine, nonyl mercaptan, dodecyl mercaptan, triazine thiol, triazine dithiol, tria Mercaptans such as N-trithiol, sugars such as glucose and cellulose, 1-propanol, 2-propanol, 2-propyn-1-ol, allyl alcohol, ethylene cyanohydrin, 1-butanol, 2-butanol, (S)-(+) 2-butanol, 2-methyl-1-propanol, t-butyl alcohol, perfluoro-t-butyl alcohol, crotyl alcohol, 1-pentanol, 2,2-dimethyl-1-propanol, 2-methyl-2 -Butanol, 3-methyl-1-butanol, S-amyl alcohol, 1-hexanol, 4-hydroxy-4-methyl-2-pentanone, 4-methyl-2-pentanol, cyclohexanol, DL-3-hexyl alcohol 1-heptanol, 2-ethylhexyl alcohol, (S )-(+)-2-octanol, 1-octanol, DL-3-octyl alcohol, 2-hydroxybenzyl alcohol, 2-nitrobenzyl alcohol, 3,5-dihydroxybenzyl alcohol, 3,5-dinitrobenzyl alcohol, 3 -Fluorobenzyl alcohol, 3-hydroxybenzyl alcohol, 4-fluorobenzyl alcohol, 4-hydroxybenzyl alcohol, benzyl alcohol, m- (trifluoromethyl) benzyl alcohol, m-aminobenzyl alcohol, m-nitrobenzyl alcohol, o- Aminobenzyl alcohol, o-hydroxybenzyl alcohol, p-hydroxybenzyl alcohol, p-nitrobenzyl alcohol, 2- (p-fluorophenyl) ethanol, 2-aminophenethyla Cole, 2-methoxybenzyl alcohol, 2-methyl-3-nitrobenzyl alcohol, 2-methylbenzyl alcohol, 2-nitrophenethyl alcohol, 2-phenylethanol, 3,4-dimethylbenzyl alcohol, 3-methyl-2-nitro Benzyl alcohol, 3-methyl-4-nitrobenzyl alcohol, 3-methylbenzyl alcohol, 4-fluorophenethyl alcohol, 4-hydroxy-3-methoxybenzyl alcohol, 4-methoxybenzyl alcohol, 4-methyl-3-nitrobenzyl alcohol , 5-methyl-2-nitrobenzyl alcohol, DL-α-hydroxyethylbenzene, o- (trifluoromethyl) benzyl alcohol, p- (trifluoromethyl) benzyl alcohol, p-aminophenethyla Alcohol such as alcohol, p-hydroxyphenylethanol, p-methylbenzyl alcohol and S-phenethyl alcohol, phenol such as 4-methylphenol, 4-ethylphenol and 4-propylphenol, glycerin ester, sorbitan ester, methoxyacetic acid, ethoxy Esters such as acetic acid, 3-ethoxypropionic acid and alanine ethyl ester, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol alkyl ether, polyethylene glycol alkenyl ether, alkyl polyethylene glycol, alkyl polyethylene glycol alkyl ether, alkyl polyethylene glycol alkenyl Ether, alkenyl polyethylene glycol, alkeni Polyethylene glycol alkyl ether, alkenyl polyethylene glycol alkenyl ether, polypropylene glycol alkyl ether, polypropylene glycol alkenyl ether, alkyl polypropylene glycol, alkyl polypropylene glycol alkyl ether, alkyl polypropylene glycol alkenyl ether, alkenyl polypropylene glycol, alkenyl polypropylene glycol alkyl ether and alkenyl polypropylene glycol Ethers such as alkenyl ether, alginic acid, pectic acid, carboxymethylcellulose, polysaccharides such as curdlan and pullulan, amino acid salts such as glycine ammonium salt and glycine sodium salt, polyaspartic acid, polyglutamic acid, polylysine , Polymalic acid, polymethacrylic acid, polymethacrylic acid ammonium salt, polymethacrylic acid sodium salt, polyamic acid, polymaleic acid, polyitaconic acid, polyfumaric acid, poly (p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopoly Acrylamide, polyacrylic acid ammonium salt, polyacrylic acid sodium salt, polyamic acid, polyamic acid ammonium salt, polyamic acid sodium salt such as polyglyoxylic acid and salts thereof, vinyl such as polyvinyl alcohol, polyvinyl pyrrolidone and polyacrolein Polymers, methyl taurate ammonium salt, methyl taurate sodium salt, methyl sodium sulfate salt, ethyl ammonium sulfate salt, butyl ammonium sulfate salt, vinyl sulfonate sodium salt Lium salt, 1-allylsulfonic acid sodium salt, 2-allylsulfonic acid sodium salt, methoxymethylsulfonic acid sodium salt, ethoxymethylsulfonic acid ammonium salt, 3-ethoxypropylsulfonic acid sodium salt, methoxymethylsulfonic acid sodium salt, ethoxy Methylsulfonic acid ammonium salt, 3-ethoxypropylsulfonic acid sodium salt, benzenesulfonic acid salt and sulfosuccinic acid sodium salt and other sulfonic acids and their salts, methyl phosphate, dimethyl phosphate, trimethyl phosphate, ethyl phosphate, phosphoric acid Diethyl, triethyl phosphate, butyl phosphate, dibutyl phosphate, tributyl phosphate, dimethyl 2-hydroxyethylphosphonate, dimethyl phosphite, diethyl phosphite, 1-hydroxyethane-1,1-diphosphonic acid, nitro Lotrismethylenephosphonic acid, tetrakis (hydroxymethyl) -phosphonium sulfate, α-naphthyl phosphate, phenyl phosphate, diphenyl phosphate, triphenyl phosphate, p-ethylbenzenephosphonic acid, phenylphosphonic acid, phenylphosphinic acid, these Esters and salts thereof, aromatic amines such as aniline, N, N-dimethylaniline and benzylamine, nitriles such as acetonitrile and benzonitrile, propionamide, acrylamide, methylurea, nicotinamide, succinamide, phenylacetamide Amides such as pyridine-4-carboxamide, N, N′-dibenzyl-L-tartaric acid amide and sulfanilamide, 1,1′-azobis (cyclohexane-1-carbonitrile), 1,1′-azobis (1-acetoxy -1-phenylethane), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis ( Isobutyric acid) dimethyl, 2,2′-azobis (isobutyronitrile), 2- [2- (3,5-dibromopyridyl) azo] -5-dimethylaminobenzoic acid, 4,4′-azobis (4- Cyanovaleric acid), 4,4′-azoxyanisole, azoxymethane, azobenzene, azoxybenzene, azodicarbonamide, diisopropyl azodicarboxylate, di (t-butyl) azodicarboxylate, phenazine, malachite green, methyl orange, Congo -Azo compounds such as red and crystal violet, disodium molybdate (VI) dihydrate and hexamolybdate (VI) acid hexa Molybdenum compounds such as ammonium tetrahydrate, lauryl sulfate triethanolamine, ammonium lauryl sulfate, laurylbenzenesulfonic acid triethanolamine, polyoxyethylene lauryl ether sulfate triethanolamine, polycarboxylic acid type polymer surfactant, coconut oil fatty acid Anionic surfactants such as acylalanine triethanolamine, coconut oil fatty acid glutamate triethanolamine, lauric acid glutamate triethanolamine, coconut oil fatty acid alaninate triethanolamine, sarcosine derivatives, lauric acid triethanolamine, polyoxyethylene lauryl Ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene high grade Lucol ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyalkylene alkyl ether, polyoxyethylene derivatives, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostea Rate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbite tetraoleate, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate , Polyethylene glycol monooleate, polyoxyethylene alkyl Nonionic surfactants such as amine, polyoxyethylene hydrogenated castor oil, alkyl alkanolamide, coconut amine acetate, stearylamine acetate, etc., and water-soluble amphoteric surfactants include, for example, lauryl betaine, stearyl betaine And cationic surfactants such as lauryldimethylamine oxide and 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine.

These may be used alone or in appropriate combination. Among these, polyacrylic acid, benzenesulfonic acid, benzonitrile, phenylphosphonic acid, coconut oil fatty acid sarcosine triethanolamine are preferable.

  Although the upper limit of content of the protective film formation agent in polishing composition is not specifically limited, It is preferable that it is 50 mass%, More preferably, it is 10 mass%, More preferably, it is 1 mass%. As the content of the protective film forming agent decreases, the polishing rate increases.

  The lower limit of the content of the protective film forming agent in the polishing composition is not particularly limited, but is preferably 0.001% by mass, more preferably 0.01% by mass, and still more preferably 0.1% by mass. is there. As the content of the protective film forming agent increases, defects such as dishing of the metal wiring layer can be suppressed.

  Examples of substances that impair the stability of the specific oxidizing agent in the present embodiment with respect to the protective film forming agent include dithizone, cuproin (2,2′-biquinoline), neocuproin (2,9-dimethyl-1,10-). Imines such as phenanthroline), bathocuproine (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and cuperazone (biscyclohexanone oxalylhydrazone), benzimidazole-2-thiol, 2- [2- (benzothiazolyl) Thiopropionic acid, 2- [2- (benzothiazolyl)] thiobutyric acid, 2-mercaptobenzothiazole), 1,2,3-triazole, 1,2,4-triazole, 3-amino-1H-1,2, 4-triazole, benzotriazole, 1-hydroxybenzotriazole, 1 Dihydroxypropylbenzotriazole, 2,3-dicarboxypropylbenzotriazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole, 4-methoxycarbonyl-1H-benzotriazole, 4-butoxycarbonyl-1H-benzotriazole, 4-octyloxycarbonyl-1H-benzotriazole, 5-hexylbenzotriazole, N- (1,2,3-benzotriazolyl-1-methyl) -N- (1,2,4-triazolyl-1-methyl) And azoles such as 2-ethylhexylamine, tolyltriazole, naphthotriazole, and bis [(1-benzotriazolyl) methyl] phosphonic acid. The reason why these impair the stability of the specific oxidant in this embodiment is not clear, but the structure that probably exhibits chelating action, and the —N═N— bond is preferentially different from the specific oxidant in this embodiment. It seems to be because it reacts.

  In the polishing composition, it is preferable that a substance that impairs the stability of the specific oxidizing agent in the present embodiment is not contained as much as possible or has a low content. In this case, the upper limit of the content is preferably 5% by mass.

(Polishing composition pH and pH adjuster)
Although the upper limit of pH of polishing composition is not specifically limited, It is preferable that it is 12, More preferably, it is 10, More preferably, it is 8. As the pH of the polishing composition decreases, there is an effect of improving the stability of the oxidizing agent, and as a result, the effect of increasing the reproducibility of the polishing rate with high Ru and its stability can be obtained.

  The lower limit of the pH of the polishing composition is not particularly limited, but is preferably 4, more preferably 3, and still more preferably 2. As the pH of the polishing composition decreases, there is a further effect of improving the stability of the oxidizing agent. As a result, it is possible to obtain the effect of increasing the reproducibility of the polishing rate with high Ru and its stability.

  The pH adjuster used as necessary to adjust the pH of the polishing composition to a desired value may be either acid or alkali, and may be any of inorganic and organic compounds. . What is necessary is just to select suitably so that the effect of the polishing rate improvement by the polishing composition of this embodiment may not be impaired.

According to this embodiment, the following operations and effects can be obtained.
The polishing composition of this embodiment contains abrasive grains and a specific oxidizing agent. This oxidizing agent has an ability to bring the surface of a barrier layer containing a noble metal having stable characteristics into an oxidized state, that is, an ability to form an oxide film of noble metal. Thereby, mechanical removal of an abrasive grain is attained. This is considered to be the reason why a high removal rate can be obtained when a barrier layer containing a noble metal is polished using the polishing composition of the present embodiment. Therefore, the polishing composition of the present embodiment is used for polishing a noble metal, more specifically, by polishing the surface of an object to be polished having a barrier layer containing the noble metal to remove a part of the noble metal oxide portion. It can be suitably used in applications for producing a substrate having a barrier layer containing.

The embodiment may be modified as follows.
The polishing composition of the above embodiment is not a substance that impairs the stability of a specific oxidizing agent, and is a substance that does not inhibit the oxidizing action of a specific oxidizing agent on a barrier layer containing a noble metal, as necessary. You may further contain well-known additives, such as surfactant, water-soluble polymer, and antiseptic | preservative.
The polishing composition of the above embodiment may be a one-component type or a multi-component type including a two-component type.
-The polishing composition of the said embodiment may be prepared by diluting the undiluted | stock solution of polishing composition with water.

Next, examples and comparative examples of the present invention will be described.
The polishing composition of Examples 1-12 and Comparative Examples 1-26 was adjusted by mixing each component so that it might become a composition of Table 1 and Table 2. The “content (mass%)” column in the “abrasive grain” column in Tables 1 and 2 shows the content of the abrasive grains in each polishing composition. As the abrasive grains here, colloidal silica having a volume average particle size of about 70 nm (average primary particle size of 35 nm, average association degree of 2) was used. In the “Kind” column of the “Oxidizing agent” column in Tables 1 and 2, the type of oxidizing agent contained in each polishing composition in each Example or Comparative Example is shown. Further, the “content (mass%)” column in the “oxidant” column of Tables 1 and 2 shows the content of the oxidant in each polishing composition. In “Type” column of “Polishing accelerator or protective film forming agent” column in Table 2, formation of polishing accelerator or protective film contained in each polishing composition in each Example or Comparative Example shown in Table 2 Indicates the type of agent. In addition, the parenthesis written under the substance name in the same column indicates the purpose of adding the substance in each polishing composition. Further, the “content (mass%)” column of the “polishing accelerator or protective film forming agent” column of Table 2 shows the content of the polishing accelerator or protective film forming agent in each polishing composition. The “-” notation here indicates that the additive is not contained. The “pH” column in Tables 1 and 2 shows the pH in each polishing composition. The pH was adjusted to a predetermined value by appropriately adding a 70% by mass aqueous solution of isethionic acid or a 48% by mass aqueous potassium hydroxide solution.

  Using each of the polishing compositions of Examples 1 to 12 and Comparative Examples 1 to 26, Ru blanket wafers were polished under the conditions shown in Table 3. The polishing rate when polishing for a certain period of time under the conditions shown in Table 3 was determined by dividing the difference in thickness of the patterned wafer before and after polishing obtained from the measurement of sheet resistance by the direct current four-probe method by the polishing time. The results are shown in the “Removal Rate” column of the “Evaluation” column of Tables 1 and 2.

  As shown in Table 1 and Table 2, when the polishing compositions of Examples 1 to 12 were used, the polishing rate was higher than that of the polishing compositions of Comparative Examples 1 to 26 that did not satisfy the conditions of the present invention. It was confirmed that the method had a remarkably excellent effect.

Claims (9)

A polishing composition used for polishing a polishing object having a barrier layer containing a noble metal and a metal wiring layer,
Containing abrasive grains, oxidant, and water,
The polishing composition according to claim 1, wherein the oxidizing agent has a structure in which any one selected from ammonium, an alkali metal, and an alkaline earth metal is substituted on oxygen of a peroxy group (—O—O—).   The polishing composition according to claim 1, wherein the oxidizing agent is at least one selected from ammonium salts of peroxomonosulfuric acid, alkali metal salts, and alkaline earth metal salts.   The polishing composition according to claim 1 or 2, further comprising a polishing accelerator.   The polishing composition according to claim 3, wherein the polishing accelerator has an effect of maintaining or improving the polishing rate of the barrier layer containing the noble metal.   The polishing composition according to any one of claims 1 to 4, further comprising a protective film forming agent.   The polishing composition according to claim 5, wherein the protective film forming agent maintains or does not suppress the polishing rate of the barrier layer containing the noble metal.   The polishing composition according to claim 1, wherein the noble metal is ruthenium.   A polishing method comprising polishing the surface of an object to be polished having a barrier layer containing a noble metal and a metal wiring layer using the polishing composition according to claim 1.   A polishing object having a barrier layer containing a noble metal and a metal wiring layer in order to obtain a substrate containing a barrier layer containing a noble metal and a metal wiring layer using the polishing composition according to any one of claims 1 to 8. A method for manufacturing a substrate having a barrier layer containing a noble metal, comprising polishing a surface of an object to remove a part of the barrier layer containing a noble metal.