JP2014072336A - Polishing composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing composition capable of suppressing an occurrence of a recess at a side of a wiring while suppressing dishing.SOLUTION: The polishing composition used for polishing an object to be polished having a conductive material layer includes a polishing accelerator and a first metal anticorrosive, wherein a ratio (X/Y) of molecular weight X of the polishing accelerator and molecular weight Y of the metal anticorrosive is 1 or over.

Description

  The present invention relates to a polishing composition.

  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.

  When forming a wiring of a semiconductor device, generally, first, a barrier layer and a conductive material layer are sequentially formed on an insulating film having a trench. Then, by chemical mechanical polishing (CMP), at least a portion of the conductive material layer located outside the trench (an outer portion of the conductive material layer) and a portion of the barrier layer located outside the trench (the outer portion of the barrier layer) Remove. The polishing for removing at least the outer portion of the conductive material layer and the outer portion of the barrier layer is usually performed in a first polishing step and a second polishing step. In the first polishing step, a part of the outer portion of the conductive material layer is removed to expose the upper surface of the barrier layer. In the subsequent second polishing step, at least the remaining portion of the outer portion of the conductive material layer and the outer portion of the barrier layer are removed in order to expose the insulating film and obtain a flat surface.

  In CMP for forming the wiring of such a semiconductor device, it is common to use a polishing composition containing a polishing accelerator such as an acid and an oxidizing agent, and further containing abrasive grains as necessary. is there. It has also been proposed to use a polishing composition to which a metal anticorrosive is further added in order to improve the flatness of the polished object after polishing, that is, to suppress dishing in which the wiring portion is overpolished. For example, Patent Document 1 discloses a polishing composition containing aminoacetic acid and / or amidosulfuric acid, an oxidizing agent, benzotriazole, and water. Patent Document 2 discloses a polishing composition containing an anionic surfactant such as polyoxyethylene lauryl ether ammonium sulfate, a protective film forming agent such as benzotriazole, and a nonionic surfactant such as polyoxyethylene alkyl ether. It is disclosed. Further, Patent Document 3 discloses a polishing composition containing an epihalohydrin-modified polyamide.

JP-A-8-83780 JP 2008-41781 A JP 2002-110595 A

  When the wiring of a semiconductor device, particularly a semiconductor device whose conductive material layer is made of copper or a copper alloy, is formed by CMP, an unintended indentation may occur on the side of the formed wiring. This dent on the side of the wiring is thought to be caused mainly by the corrosion of the surface of the portion of the conductive material layer located near the boundary with the insulating film during polishing. When the polishing composition as disclosed is used, dishing is suppressed, but it is difficult to prevent the recesses on the side of the wiring from occurring.

  Then, an object of this invention is to provide the polishing composition which can suppress that the dent of a wiring side arises, suppressing dishing.

  In order to solve the above-mentioned problems, the present inventors have intensively studied. As a result, a polishing composition comprising a polishing accelerator and a metal anticorrosive, wherein the ratio (X / Y) of the molecular weight X of the polishing accelerator to the molecular weight Y of the metal anticorrosive is 1 or more is used. Then, it discovered that the said subject could be solved. And based on the said knowledge, it came to complete this invention.

  That is, the present invention is a polishing composition used for polishing an object to be polished having a conductive material layer, comprising a polishing accelerator and a first metal anticorrosive, and the polishing acceleration It is polishing composition whose ratio (X / Y) of the molecular weight X of an agent and the molecular weight Y of a said 1st metal anticorrosive is 1 or more.

  ADVANTAGE OF THE INVENTION According to this invention, the polishing composition which can suppress that the dent of a wiring side arises can be provided.

It is the photograph which observed the dent by the side of the wiring of a grinding | polishing target object with the scanning electron microscope (SEM), after grind | polishing a grinding | polishing target object using the polishing composition of Example 1. FIG. It is the photograph which observed the dent by the side of the wiring of a grinding | polishing target object by SEM, after grind | polishing a grinding | polishing target object using the polishing composition of Example 2. FIG. It is the photograph which observed the dent by the side of the wiring of a grinding | polishing target object by SEM, after grind | polishing a grinding | polishing target object using the polishing composition of Example 3. FIG. 6 is a photograph of a polishing object observed by SEM after polishing the polishing object using the polishing composition of Comparative Example 1 and then polishing the wiring side of the polishing object. 6 is a photograph of a polishing object observed by SEM after polishing the polishing object using the polishing composition of Comparative Example 2 and then polishing the wiring side of the polishing object. 6 is a photograph of a polishing object observed by SEM after polishing the polishing object with the polishing composition of Comparative Example 3 and then polishing the wiring side recess of the polishing object.

  The present invention is a polishing composition for use in polishing an object to be polished having a conductive material layer, comprising a polishing accelerator and a first metal anticorrosive, and the polishing accelerator It is polishing composition whose ratio (X / Y) of molecular weight X and molecular weight Y of said 1st metal anticorrosive is 1 or more. By setting it as such a structure, it can suppress that the dent of the wiring side arises, suppressing dishing.

  Although the detailed reason why the above-described effects can be obtained by using the polishing composition of the present invention is unknown, the smaller the molecular weight of the metal anticorrosive, the more uniform the anticorrosion film can be formed, and the As a result, the anticorrosion effect at the side of the wiring can be obtained more efficiently. On the other hand, when a polishing accelerator having a molecular weight smaller than that of the metal anticorrosive agent is used so that X / Y is less than 1, polishing is further promoted, and dents on the wiring side are likely to occur. Therefore, by using a combination of a polishing accelerator and a metal anticorrosive so that the above X / Y is 1 or more, while maintaining the polishing acceleration effect, dishing is suppressed and a dent on the side of the wiring is generated. It is thought that it can be suppressed. In addition, the said mechanism is based on estimation and this invention is not limited to the said mechanism at all.

[Polishing object]
The object to be polished according to the present invention has a conductive material layer and, if necessary, a barrier layer and an insulating film.

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

  The material contained in the barrier layer is not particularly limited, and examples thereof include tantalum, titanium, tungsten, cobalt; noble metals such as gold, silver, platinum, palladium, rhodium, ruthenium, iridium, and osmium. These metals may be contained in the barrier layer in the form of an alloy or a metal compound. These metals may be used alone or in combination of two or more.

  Examples of the material included in the insulating film include TEOS (tetraethoxysilane).

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

[Polishing accelerator]
The polishing composition according to the present invention contains a polishing accelerator. The polishing accelerator functions to improve the polishing rate of the polishing object by the polishing composition by complexing and bonding to the surface of the polishing object and forming an insoluble brittle film on the surface of the polishing object. . Further, the etching action of the polishing accelerator has an advantageous effect that the polishing rate of the object to be polished by the polishing composition is improved.

  As the polishing accelerator, for example, an inorganic acid, an organic acid, an amino acid, a nitrile compound, a chelating agent, 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, cytosine Phosphorus, .delta.-hydroxy - lysine, creatine, histidine, 1-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 acetonitrile, aminoacetonitrile, propionitrile, butyronitrile, isobutyronitrile, benzonitrile, glutaronitrile, methoxyacetonitrile, and the like.

  Specific examples of chelating agents include nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, N, N, N-trimethylenephosphonic acid, ethylenediamine-N, N, N ′, N′-tetramethylenesulfonic acid, transcyclohexane Diamine tetraacetic 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 diacetate, 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-dihydroxybenzene-4,6 Such as disulfonic acid and the like.

  Among these polishing accelerators, a polishing accelerator having a molecular weight X of 90 or less is preferable, a polishing accelerator having a molecular weight X of 65 or more and 90 or less is preferable, and an inorganic acid or an organic acid having a molecular weight X of 65 or more and 90 or less, Or an amino acid is still more preferable. By using such a compound, the effect of the present invention can be obtained more efficiently.

  The lower limit of the content of the polishing accelerator in the polishing composition is preferably 0.01 g / L or more, more preferably 0.1 g / L or more, and further preferably 1 g / L or more. As the content of the polishing accelerator increases, the polishing rate of the object to be polished by the polishing composition is improved. On the other hand, the upper limit of the content of the polishing accelerator in the polishing composition is preferably 50 g / L or less, more preferably 30 g / L or less, and even more preferably 15 g / L or less. As the content of the polishing accelerator decreases, the material cost of the polishing composition can be reduced.

[Metal anticorrosive]
The polishing composition according to the present invention contains a metal anticorrosive. By adding a metal anticorrosive to the polishing composition, it serves to further suppress the formation of dents on the side of the wiring formed by polishing using the polishing composition. Moreover, it plays the role which suppresses more that dishing arises on the surface of the grinding | polishing target object after grind | polishing using a polishing composition.

  The metal anticorrosive essentially includes those having a molecular weight Y that is the same as or smaller than the molecular weight X of the polishing accelerator, that is, those satisfying the relationship that X / Y is 1 or more (in this specification, this relationship The metal anticorrosive satisfying the above condition is also referred to as a first metal anticorrosive, and is not particularly limited. From the viewpoint of obtaining the effect of the present invention more efficiently, the X / Y is preferably 1.05 or more.

  Although the 1st metal anticorrosive which can be used is not specifically limited, Preferably it is a heterocyclic compound. 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. In addition, the said 1st metal anticorrosive agent can be used individually or in combination of 2 or more types.

  More specific examples of compounds that can be used as the first metal corrosion inhibitor include, for example, pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, pyridine compounds, pyrazine compounds, pyridazine compounds, pyridine compounds, and India. Lysine compound, indole 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, Nitrogen-containing heterocyclic compounds, such as an oxazole compound, an isoxazole compound, and a furazane compound, are mentioned.

  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, 1H-1,2,3-triazole, 1H-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-triazole, 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-be Zotriazole, 1- (1 ′, 2′-dicarboxyethyl) benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, 1- [N, N-bis (hydroxyethyl) amino Methyl] -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, a preferable first metal anticorrosive is a nitrogen-containing five-membered ring compound, and at least one selected from the group consisting of 1H-pyrazole, 1,2,4-triazole, and 1H-tetrazole is more preferable. By using these compounds, corrosion of the interface between the wiring and the insulating film can be suppressed when the wafer on which the wiring is formed is polished.

  The lower limit of the content of the first metal anticorrosive in the polishing composition is preferably 0.001 g / L or more, more preferably 0.005 g / L or more, and still more preferably 0.01 g / L or more. It is. Moreover, it is preferable that the upper limit of content of the 1st metal anticorrosive agent in polishing composition is 10 g / L or less, More preferably, it is 5 g / L or less, More preferably, it is 2 g / L or less. If it is such a range, the flatness of the surface of the grinding | polishing target object after grind | polishing using a polishing composition will improve, and the grinding | polishing speed | rate of the grinding | polishing target object by polishing composition will improve.

  The polishing composition according to the present invention further includes a second metal anticorrosive agent that is different from the first metal anticorrosive agent (that is, X / Y is less than 1) from the viewpoint of preventing corrosion of the wiring metal. Form is preferred. At this time, the second metal anticorrosive can be arbitrarily selected from the metal anticorrosives exemplified above. The lower limit of the content in the polishing composition when using the second metal corrosion inhibitor is preferably 0.01 g / L or more, more preferably 0.05 g / L or more, and still more preferably 0. .1 g / L or more. Moreover, it is preferable that the upper limit of content of the 2nd metal anticorrosive agent in polishing composition is 10 g / L or less, More preferably, it is 5 g / L or less, More preferably, it is 2 g / L or less. In addition, the said 2nd metal corrosion inhibitor can be used individually or in combination of 2 or more types.

[water]
The polishing composition of the present invention preferably contains 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.

[Other ingredients]
The polishing composition of the present invention comprises abrasive grains, complexing agents, metal anticorrosives, antiseptics, antifungal agents, oxidizing agents, reducing agents, water-soluble polymers, surfactants, and poorly soluble materials as necessary. Other components such as an organic solvent for dissolving the organic substance may be further included. Hereinafter, abrasive grains, an oxidizing agent, and a surfactant, which are other preferable components, will be described.

[Abrasive]
The abrasive grains contained in the polishing composition have an action of mechanically polishing the object to be polished, and improve 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. 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 negative value even under acidic conditions are strongly repelled from each other and dispersed well even under acidic conditions, resulting in storage of the polishing composition. Stability will be improved. Such surface-modified abrasive grains can be obtained, for example, by mixing a metal such as aluminum, titanium or zirconium or an oxide thereof with the abrasive grains and doping the surface of the abrasive grains.

  Of these, colloidal silica having an organic acid immobilized thereon is particularly preferable. The organic acid is immobilized on the surface of the colloidal silica contained in the polishing composition, for example, by chemically bonding a functional group of the organic acid to the surface of the colloidal silica. If the colloidal silica and the organic acid are simply allowed to coexist, the organic acid is not fixed to the colloidal silica. If sulfonic acid, which is a kind of organic acid, is immobilized on colloidal silica, for example, the method described in “Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups”, Chem. Commun. 246-247 (2003). It can be carried out. Specifically, a silane coupling agent having a thiol group such as 3-mercaptopropyltrimethoxysilane is coupled to colloidal silica, and then the sulfonic acid is immobilized on the surface by oxidizing the thiol group with hydrogen peroxide. The colloidal silica thus obtained can be obtained. Alternatively, if the carboxylic acid is immobilized on colloidal silica, for example, “Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel”, Chemistry Letters, 3, 228- 229 (2000). Specifically, colloidal silica having a carboxylic acid immobilized on the surface can be obtained by irradiating light after coupling a silane coupling agent containing a photoreactive 2-nitrobenzyl ester to colloidal silica. .

  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 0.005% by weight or more, more preferably 0.01% by weight or more, and more preferably 0.1% by weight or more. More preferred is 3% 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, and further preferably 15% by weight or less. Within such a range, the polishing rate of the polishing object can be improved, and the cost of the polishing composition can be reduced, and dishing is performed on the surface of the polishing object after polishing using the polishing composition. Can be further suppressed.

〔Oxidant〕
The oxidizing agent contained in the polishing composition has an action of oxidizing the surface of the object to be polished, and improves the polishing rate of the object to be polished by the polishing composition.

  An oxidizing agent that can be used is, for example, a peroxide. Specific examples of the peroxide include hydrogen peroxide, peracetic acid, percarbonate, urea peroxide and perchloric acid, and persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate. These oxidizing agents may be used alone or in combination of two or more. Of these, persulfate and hydrogen peroxide are preferable, and hydrogen peroxide is particularly preferable.

  The content of the oxidizing agent in the polishing composition is preferably 0.1 g / L or more, more preferably 1 g / L or more, and further preferably 3 g / L or more. As the content of the oxidizing agent increases, the polishing rate of the object to be polished by the polishing composition increases.

  The content of the oxidizing agent in the polishing composition is also preferably 200 g / L or less, more preferably 100 g / L or less, and still more preferably 40 g / L or less. As the content of the oxidizing agent decreases, the material cost of the polishing composition can be reduced, and the load on the processing of the polishing composition after polishing, that is, the waste liquid treatment can be reduced. In addition, the possibility of excessive oxidation of the surface of the object to be polished by the oxidizing agent can be reduced.

[Surfactant]
When a surfactant is added to the polishing composition, dents are less likely to be formed on the sides of the wiring formed by polishing using the polishing composition, and polishing is performed using the polishing composition. There is an advantage that dishing is less likely to occur on the surface of the polished object after the polishing.

  The surfactant used may be any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant and a nonionic surfactant, and among them, an anionic surfactant and Nonionic surfactants are preferred. A plurality of types of surfactants may be used in combination, and it is particularly preferable to use a combination of an anionic surfactant and a nonionic surfactant.

  Specific examples of the anionic surfactant include, for example, polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl ether sulfuric acid, alkyl ether sulfuric acid, polyoxyethylene alkyl sulfuric acid ester, alkyl sulfuric acid ester, polyoxyethylene alkyl sulfuric acid, alkyl Examples include sulfuric acid, alkylbenzene sulfonic acid, alkyl phosphoric acid ester, polyoxyethylene alkyl phosphoric acid ester, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthalene sulfonic acid, alkyl diphenyl ether disulfonic acid, and salts thereof. Of these, polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl ether sulfate, alkyl ether sulfate and alkylbenzene sulfonate are preferred. Since these preferable anionic surfactants have a high chemical or physical adsorption force to the surface of the object to be polished, a stronger protective film is 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 with the polishing composition.

  Specific examples of the cationic surfactant include, for example, alkyl trimethyl ammonium salt, alkyl dimethyl ammonium salt, alkyl benzyl dimethyl ammonium salt, and alkyl amine salt.

  Specific examples of amphoteric surfactants include alkyl betaines and alkyl amine oxides.

  Specific examples of nonionic surfactants include, for example, polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ether, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkyl amines, and alkyl alkanols. Amides are mentioned. Of these, polyoxyalkylene alkyl ether is preferred. Since polyoxyalkylene alkyl ether has high chemical or physical adsorption force to the surface of the polishing object, it forms a stronger protective film on the surface of the polishing object. This is advantageous in improving the flatness of the surface of the object to be polished after polishing with the polishing composition.

  The content of the surfactant in the polishing composition is preferably 0.001 g / L or more, more preferably 0.005 g / L or more, and still more preferably 0.01 g / L or more. As the content of the surfactant increases, there is an advantage that the flatness of the surface of the object to be polished after polishing with the polishing composition is improved. The content of the surfactant in the polishing composition is also preferably 10 g / L or less, more preferably 5 g / L or less, and further preferably 1 g / L or less. As the surfactant content decreases, there is an advantage that the polishing rate of the polishing composition is improved.

[PH of polishing composition]
The lower limit of the pH of the polishing composition of the present invention is preferably 3 or more. As the pH of the polishing composition increases, the risk of excessive etching of the surface of the object to be polished by the polishing composition can be reduced.

  Moreover, it is preferable that the upper limit of pH of polishing composition is 10 or less. As the pH of the polishing composition decreases, it is possible to further suppress the formation of a dent on the side of the wiring formed by polishing using the polishing composition.

  A pH adjusting agent may be used to adjust the pH of the polishing composition to a desired value. The pH adjuster to be used may be either acid or alkali, and may be any of inorganic and organic compounds. In addition, a pH adjuster can be used individually or in mixture of 2 or more types. Moreover, when using what has pH adjustment function (for example, various acids etc.) as various additives mentioned above, you may utilize the said additive as at least one part of a pH adjuster.

[Method for producing polishing composition]
The manufacturing method in particular of the polishing composition of this invention is not restrict | limited, For example, it can obtain by stirring and mixing a polishing accelerator, a metal anticorrosive, and other components as needed.

  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 conductive substance layer. Therefore, this invention provides the grinding | polishing method which grind | polishes the grinding | polishing target object which has an electroconductive substance layer using 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 an electroconductive substance layer 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 drying with a spin dryer or the like, and dried to obtain a substrate having a conductive material layer.

  The polishing composition of the present invention may be a one-component type or a multi-component type including a two-component type. The polishing composition of the present invention may be prepared by diluting the stock solution of the polishing composition, for example, 10 times or more using a diluent such as water.

  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.

(Examples 1-4, Comparative Examples 1-4)
Colloidal silica (average primary particle size 30 nm) 0.1% by weight as abrasive grains, hydrogen peroxide 15 g / L as oxidant, ammonium lauryl ether sulfate 0.1 g / L as surfactant, and polyoxyethylene alkyl ether 0.5 g / L L, and the polishing accelerator and the metal anticorrosive shown in Table 3 below are stirred and mixed in water so as to have the concentrations shown above or in Table 3, respectively (mixing temperature: about 25 ° C., mixing time: about 10 minutes), A polishing composition was prepared. The pH of the polishing composition was adjusted to pH 6.5 by adding potassium hydroxide or nitric acid.

(Evaluation of dents beside wiring)
Using the obtained polishing composition, the surface of a copper pattern wafer (copper film thickness 700 nm before polishing, trench depth 300 nm) was polished under the first polishing conditions described below until the copper film thickness reached 250 nm. . Thereafter, the surface of the polished copper pattern wafer was polished using the same polishing composition until the barrier layer (material: tantalum) was exposed under the second polishing conditions described below. The surface of the copper pattern wafer after the two-step polishing in this way is observed using a scanning electron microscope (SEM), and a 0.18 μm wide wiring and a 0.18 μm wide insulating film (material) : Tantalum) and regions where 100 μm wide wiring and 100 μm wide insulating films (material: tantalum) are alternately arranged were checked for the presence or absence of dents on the side of the wiring. The evaluation results are shown in Table 3 below. In Table 3, ◎ (excellent) when no dent on the side of the wiring was confirmed in any region, ○ when dent on the side of the wiring having a width of less than 10 nm was confirmed in either region. (Good), if a dent on the side of the wiring having a width of 10 nm or more and less than 50 nm is confirmed in any one region, Δ (possible), if a dent having a width of 50 nm or more is confirmed in at least one of the regions X (defect).

  Moreover, after grind | polishing using the polishing composition of Examples 1-3 and Comparative Examples 1-3, the photograph (magnification: 5000 times) which observed the dent of the wiring side by SEM is shown to FIGS.

(Dishing rating)
Using the obtained polishing composition, the copper film thickness becomes 250 nm on the surface of the copper pattern wafer (copper film thickness 700 nm before polishing, trench depth 300 nm) under the first polishing conditions described in Table 1 below. Polished until. Thereafter, the polished copper pattern wafer surface was polished using the same polishing composition until the barrier layer (material: tantalum) was exposed under the second polishing conditions described in Table 2 below. The first region in which the 9 μm-width wiring and the 1 μm-width insulating film (material: tantalum) of the copper pattern wafer after the two-step polishing are alternately arranged, and the 5 μm-width wiring, In a second region where insulating films (material: tantalum) having a width of 1 μm were alternately arranged, the dishing amount (dishing depth) was measured using an atomic force microscope. The evaluation results are shown in Table 3 below. The measured dishing amount is 200 nm or less in the case of the first region and 120 nm or less in the case of the second region, which is a practical level. Was evaluated as “◯”, and “x” was used when neither or both were achieved.

  As shown in Table 3 and FIGS. 1 to 6, the polishing composition of the present invention (Examples 1 to 4) has a recess on the side of the wiring as compared with the polishing compositions of Comparative Examples 1 to 4. There was almost nothing, and dishing was at a practical level. As shown in FIGS. 4-6, when the polishing composition of Comparative Examples 1-3 is used, a dent will generate | occur | produce on the interface of copper and a tantalum, ie, wiring side.

Claims (7)

A polishing composition used for polishing a polishing object having a conductive material layer,
A polishing accelerator;
A first metal corrosion inhibitor;
Including
Polishing composition whose ratio (X / Y) of the molecular weight X of the said polishing accelerator and the molecular weight Y of the said 1st metal anticorrosive is 1 or more.   The polishing composition according to claim 1, wherein the polishing accelerator has a molecular weight X of 65 or more and 90 or less.   The polishing composition according to claim 1 or 2, wherein the first metal anticorrosive is a nitrogen-containing five-membered ring compound.   The first metal anticorrosive agent is at least one selected from the group consisting of 1H-pyrazole, 1H-1,2,4-triazole, and 1H-tetrazole. The polishing composition as described.   The polishing composition according to any one of claims 1 to 4, further comprising a second metal anticorrosive agent different from the first metal anticorrosive agent.   The grinding | polishing method which grind | polishes the grinding | polishing target object which has an electroconductive substance layer using the polishing composition of any one of Claims 1-5.   The manufacturing method of a board | substrate including the process of grind | polishing the grinding | polishing target object which has an electroconductive substance layer with the grinding | polishing method of Claim 6.