WO2016038995A1 - 研磨用組成物 - Google Patents
研磨用組成物 Download PDFInfo
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- WO2016038995A1 WO2016038995A1 PCT/JP2015/069198 JP2015069198W WO2016038995A1 WO 2016038995 A1 WO2016038995 A1 WO 2016038995A1 JP 2015069198 W JP2015069198 W JP 2015069198W WO 2016038995 A1 WO2016038995 A1 WO 2016038995A1
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- Prior art keywords
- polishing
- acid
- cobalt
- group
- polishing composition
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09G—POLISHING COMPOSITIONS; SKI WAXES
- C09G1/00—Polishing compositions
- C09G1/02—Polishing compositions containing abrasives or grinding agents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
- B24B37/042—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor
- B24B37/044—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor characterised by the composition of the lapping agent
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/14—Anti-slip materials; Abrasives
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/14—Anti-slip materials; Abrasives
- C09K3/1409—Abrasive particles per se
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
- H01L21/321—After treatment
- H01L21/32115—Planarisation
- H01L21/3212—Planarisation by chemical mechanical polishing [CMP]
Definitions
- the present invention relates to a polishing composition, and more particularly to a polishing composition suitable for polishing a polishing object having a layer containing copper and a layer containing cobalt.
- CMP Chemical mechanical polishing
- a general method of CMP is to apply a polishing pad on a circular polishing platen (platen), immerse the polishing pad surface with an abrasive, press the surface on which the metal film of the substrate is formed, The polishing surface plate is rotated in a state where 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.
- polishing pressure hereinafter also simply referred to as polishing pressure
- a barrier layer is formed below the conductive material (copper, copper alloy, etc.) forming the damascene wiring in order to prevent the conductive material from diffusing into the interlayer insulating film.
- conductive material copper, copper alloy, etc.
- tantalum, a tantalum alloy, a tantalum compound, or the like has been used as a material constituting the barrier layer (see, for example, Japanese Patent Laid-Open Nos. 2001-85372 and 2001-139937).
- damascene wiring technology In the damascene wiring technology, generally, after forming a barrier layer and a metal wiring layer on an insulator layer provided with a trench, an operation of removing excess wiring material (metal wiring layer) and the barrier layer other than the wiring portion by CMP is performed. Done.
- a polishing composition capable of suppressing dissolution of the layer containing cobalt element while exhibiting a high polishing rate for the layer containing copper. Is required.
- this invention can suppress melt
- An object is to provide a polishing composition.
- the present inventors have conducted intensive research. As a result, it discovered that the said subject could be solved by using the polishing composition containing an oxidizing agent and the cobalt dissolution inhibitor selected from a specific compound group. More specifically, as a cobalt dissolution inhibitor, copper is contained by using at least one organic compound selected from the group consisting of a compound having a nitrogen-containing five-membered ring structure and a compound having two or more carboxyl groups.
- the present invention has been completed based on the knowledge that dissolution of cobalt is effectively suppressed while expressing a high polishing rate for the layer.
- the present invention is a polishing composition for use in polishing an object to be polished having a layer containing copper and a layer containing cobalt, and includes an oxidizing agent and a cobalt dissolution inhibitor,
- the cobalt dissolution inhibitor is a polishing composition that is at least one selected from the group consisting of a compound having a nitrogen-containing five-membered ring structure and a compound having two or more carboxyl groups.
- 1 is an SEM (scanning electron microscope) photograph showing a cross section of a pattern after polishing a cobalt / copper patterning wafer using the polishing composition of Example 10, wherein 1 indicates a barrier layer (Ta layer), 2 Indicates a layer containing copper. It is a SEM (scanning electron microscope) photograph which shows the cross section of the pattern after grind
- the present invention provides a polishing composition used for polishing an object to be polished having a copper-containing layer and a cobalt-containing layer, comprising an oxidizing agent and a cobalt dissolution inhibitor, wherein the cobalt dissolution
- the inhibitor is a polishing composition that is at least one selected from the group consisting of a compound having a nitrogen-containing five-membered ring structure and a compound having two or more carboxyl groups.
- Cobalt that constitutes the barrier layer or the like is water used during polishing when it is weakly acidic to alkaline (about pH of 4 or more and 12 or less) which is a general barrier layer (and metal wiring layer) polishing condition. It is easy to be oxidized by etc. As a result, it is considered that the cobalt whose surface is oxidized is easily dissolved when CMP is performed.
- the outermost surface of cobalt is covered with a hydroxy group (—OH) or the like.
- the cobalt dissolution inhibitor according to the present invention is in such a form that it is coordinated to this hydroxy group or forms a complex, so to speak, it is considered that a protective film is formed on the surface of cobalt. As a result, it is considered that dissolution of the layer containing cobalt can be effectively suppressed.
- the oxidizing agent has an action of developing a high polishing rate for the layer containing copper. Therefore, according to the polishing composition of the present invention, dissolution of the layer containing cobalt can be suppressed while developing a high polishing rate for the layer containing copper.
- the semiconductor wiring process usually includes the following steps.
- an insulator layer having a trench is formed on a substrate.
- a barrier layer, a layer containing cobalt, and a layer containing copper which is a metal wiring layer are sequentially formed on the insulator layer.
- “including cobalt” indicates an aspect in which a cobalt element is included in a layer, and the cobalt in the layer may be a simple substance, a cobalt oxide, a cobalt compound, It may exist in the form of a cobalt alloy or the like.
- “including copper” indicates an aspect in which a copper element is included in a layer, and the copper in the layer may be a simple substance, a copper oxide, or a copper compound. Or may exist in the form of a copper alloy or the like.
- the barrier layer and the layer containing cobalt are formed on the insulator layer so as to cover the surface of the insulator layer prior to the formation of the layer containing copper (metal wiring layer).
- the method for forming these layers is not particularly limited, and can be formed by a known method such as sputtering or plating.
- the thickness of the barrier layer and the layer containing cobalt is smaller than the depth and width of the trench.
- the layer containing copper (metal wiring layer) is formed on the barrier layer so that at least the trench is filled.
- the method for forming the layer containing copper (metal wiring layer) is not particularly limited, and can be formed by a known method such as sputtering or plating.
- the layer containing copper (metal wiring layer), the layer containing cobalt, and the barrier layer other than the wiring portion are removed by CMP.
- the layer containing copper (metal wiring layer), the layer containing cobalt, and the barrier layer other than the wiring portion are removed by CMP.
- at least a part of the part of the barrier layer located in the trench (inner part of the barrier layer), at least a part of the part of the layer containing cobalt (inner part of the layer containing cobalt) located in the trench In addition, at least a part of the copper-containing layer (metal wiring layer) portion (inner portion of the copper-containing layer) located in the trench remains on the insulator layer. That is, a part of the barrier layer, a part of the layer containing cobalt, and a part of the layer containing copper remain inside the trench.
- the portion of the layer containing copper remaining inside the trench functions as a wiring.
- the metal contained in the barrier layer include, for example, tantalum, titanium, tungsten; noble metals such as gold, silver, platinum, palladium, rhodium, ruthenium, iridium, and osmium. These other metals may be used alone or in combination of two or more.
- the layer containing copper may contain a metal other than copper.
- a metal other than copper For example, aluminum, hafnium, cobalt, nickel, titanium, tungsten, etc. are mentioned. These metals may be contained in a layer containing copper in the form of an alloy or a metal compound. These metals may be used alone or in combination of two or more.
- the polishing composition according to the present invention contains an oxidizing agent.
- An oxidizing agent has the effect
- Usable oxidizing agent is, for example, peroxide.
- peroxides include, for example, halogen elements such as hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, perchlorate, chlorate, chlorite, and hypochlorite.
- halogen elements such as hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, perchlorate, chlorate, chlorite, and hypochlorite.
- Examples include oxoacid salts and persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate.
- persulfate and hydrogen peroxide are preferable from the viewpoint of polishing rate, and hydrogen peroxide is particularly preferable from the viewpoint of stability in an aqueous solution and environmental load.
- the lower limit of the content of the oxidizing agent in the polishing composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and more preferably 0.1% by mass or more. Further preferred. As the content of the oxidizing agent increases, the polishing rate of the layer containing copper can be further improved. Further, the upper limit of the content of the oxidizing agent in the polishing composition is preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% by mass or less. 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.
- the polishing composition of the present invention contains a cobalt dissolution inhibitor.
- the cobalt dissolution inhibitor is added for the purpose of suppressing the dissolution of cobalt during CMP.
- the cobalt dissolution inhibitor is at least one selected from the group consisting of a compound having a nitrogen-containing five-membered ring structure and a compound having two or more carboxyl groups.
- Compound having a nitrogen-containing five-membered ring structure examples include pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, indolizine compounds, indole compounds, isoindole compounds, indazole compounds, purine compounds, thiazole compounds, isoforms. Examples include thiazole compounds, oxazole compounds, isoxazole compounds, and furazane compounds.
- pyrrole compounds include 1H-pyrrole, 3-methylpyrrole, 3-hexylpyrrole, 3-phenylpyrrole, N-phenylpyrrole, N-ethylsulfonate pyrrole, 3, 4-cyclohexylpyrrole, N- (4-fluorophenyl) pyrrole, N- (4-chlorophenyl) pyrrole, N- (4-cyanophenyl) pyrrole, N- (4-nitrophenyl) pyrrole, N- (4-amino Phenyl) pyrrole, N- (4-methoxyphenyl) pyrrole, N- (4- (1-oxoethyl) phenyl) pyrrole, N- (4-trifluoromethylphenyl) pyrrole, N- (4-carbomethoxyphenyl) pyrrole N- (4-carboxyphenyl) pyrrole, N- (1-naphth
- pyrazole compounds include, for example, 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-methylpyrazole, 3-amino-5-methyl Pyrazole, 4-amino-pyrazolo [3,4-d] pyrimidine, 1,2-dimethylpyrazole, 4-chloro-1H-pyrazolo [3,4-D] pyrimidine, 3,4-dihydroxy-6-methylpyrazolo (3 , 4-B) -pyridine, 6-methyl-1H-pyrazolo [3,4-b] pyridin-3-amine, etc. It is below.
- imidazole compounds include 1H-imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, benzimidazole, and 5,6-dimethyl.
- Benzimidazole, 2-aminobenzimidazole, 2-chlorobenzimidazole, 2-methylbenzimidazole, 2- (1-hydroxyethyl) benzimidazole, 2-hydroxybenzimidazole, 2-phenylbenzimidazole, 2,5-dimethylbenz Examples include imidazole, 5-methylbenzimidazole, and 5-nitrobenzimidazole.
- 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-1,2 , 4-to Azole, 4- (1,2,4-triazol-1-yl) phenol, 4-amino-1,2,4-triazole,
- tetrazole compounds include, for example, 1H-tetrazole, 5,5′-bis-1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 5- Mercapto-1H-tetrazole, 1-methyl-1H-tetrazole, 1-phenyl-1H-tetrazole, 1-amino-1H-tetrazole, 1-mercapto-1H-tetrazole, 1-phenyl-5-methyl-1H-tetrazole, Examples thereof include 1-phenyl-5-amino-1H-tetrazole and 1-phenyl-5-mercapto-1H-tetrazole.
- indolizine compounds examples include indolizine and the like.
- indole compounds include, for example, 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 Indole, 5-chloro-1H-indole, 6-chloro-1H Indo
- isoindole compounds examples include 2H-isoindole and the like.
- 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 the purine compound include purine and the like.
- Examples of thiazole compounds include 1,3-thiazole and the like.
- Examples of isothiazole compounds include 1,2-thiazole and the like.
- Examples of oxazole compounds include 1,3-oxazole and the like.
- Examples of isoxazole compounds include 1,2-oxazole and the like.
- Examples of the furazane compound include 1,2,5-oxadiazole.
- 1H-benzotriazole 5-methyl-1H-benzotriazole
- 1H-imidazole 1H-imidazole
- 1H-tetrazole from the viewpoint of ensuring a high polishing rate for the layer containing copper.
- aminocarboxylic acids having two or more carboxyl groups include, for example, N, N′-bis (2-hydroxybenzyl) ethylenediamine-N, N′-diacetic acid, diethylenetriaminepentaacetic acid, triethylenetetramine-N, N , N ′′, N ′′, N ′ ′′, N ′ ′′-hexaacetic acid, nitrilotriacetic acid, N- (2-hydroxyethyl) iminodiacetic acid, N- (2-hydroxyethyl) ethylenediamine-N, N ′, N′-triacetic acid, 1,2-diaminopropane-N, N, N ′, N′-tetraacetic acid, 1,3-diaminopropane-N, N, N ′, N′-tetraacetic acid, trans -Cyclohexanediamine-N, N, N, N, N′-bis (2-hydroxybenzyl) ethylenediamine-N
- diethylenetriaminepentaacetic acid triethylenetetramine-N, N, N ′′, N ′′, N ′ ′′, N ′ ′′-hexaacetic acid from the viewpoint of securing a high polishing rate for the copper-containing layer.
- the lower limit of the content of the cobalt dissolution inhibitor in the polishing composition is preferably 0.001 mol / L or more, more preferably 0.005 mol / L or more, and 0.01 mol / L or more. More preferably. As the content of the cobalt dissolution inhibitor increases, dissolution of the layer containing cobalt can be further suppressed.
- the upper limit of the content of the cobalt dissolution inhibitor in the polishing composition is preferably 100 mol / L or less, more preferably 50 mol / L or less, and even more preferably 10 mol / L or less. . As the content of the cobalt dissolution inhibitor decreases, storage stability can be ensured.
- the polishing composition of the present invention comprises abrasive grains, a dispersion medium, a solvent, a pH adjuster, a polishing accelerator, a metal anticorrosive, a surfactant, an antiseptic, an antifungal agent, a water-soluble polymer, and the like as necessary.
- Other components may be further included. Hereinafter, the other components will be described.
- the polishing composition of the present invention preferably contains 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.
- 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.
- PMMA polymethyl methacrylate
- silica and alumina 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, the abrasive grains surface-modified so that the zeta potential has a relatively large negative value even under acidic conditions are strongly repelled and dispersed well even under acidic conditions. Storage 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.
- colloidal silica in which an organic acid is immobilized.
- 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.
- the organic acid cannot be immobilized on the colloidal silica simply by allowing the colloidal silica and the organic acid to coexist.
- a silane coupling agent having a thiol group such as 3-mercaptopropyltrimethoxysilane is coupled to colloidal silica and then oxidized with hydrogen peroxide to fix the sulfonic acid on the surface.
- the colloidal silica thus obtained can be obtained.
- 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).
- 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. .
- Cationic sol Cationic silica produced by adding a basic aluminum salt or basic zirconium salt as disclosed in JP-A-4-214222 can also be used as abrasive grains.
- the lower limit of the average primary particle diameter of the abrasive grains is preferably 3 nm or more, more preferably 5 nm or more, and even more preferably 7 nm or more.
- the upper limit of the average primary particle diameter of the abrasive grains is preferably 200 nm or less, more preferably 150 nm or less, and further preferably 100 nm or less.
- 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.
- 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 average secondary particle diameter of the abrasive grains is preferably 10 nm or more, more preferably 15 nm or more, and further preferably 20 nm or more.
- the upper limit of the average secondary particle diameter of the abrasive grains is preferably 300 nm or less, more preferably 260 nm or less, and further preferably 220 nm or less.
- the secondary particles referred to here are particles formed by association of abrasive grains in the polishing composition, and the average secondary particle diameter of the secondary particles is measured by, for example, a dynamic light scattering method. be able to.
- the lower limit of the content of abrasive grains in the polishing composition of the present invention is preferably 0.005% by mass or more and 0.01% by mass or more from the viewpoint of improving the polishing rate of the object to be polished. It is more preferable that the content is 0.1% by mass or more.
- the upper limit of the content of the abrasive grains in the polishing composition is 50% by mass or less from the viewpoint of reducing the cost of the polishing composition and suppressing the occurrence of surface defects on the surface of the polished object after polishing. It is preferable that it is preferably 30% by mass or less, and more preferably 20% by mass or less.
- a dispersion medium or a solvent for dispersing or dissolving each component is usually used.
- the dispersion medium or solvent an organic solvent and water are conceivable, and among them, water is preferably included. From the viewpoint of inhibiting the action of other components, water containing as little impurities as possible is preferable. Specifically, pure water, ultrapure water, or distilled water from which foreign ions are removed through a filter after removing impurity ions with an ion exchange resin is preferable.
- the pH of the polishing composition according to the present invention can be adjusted by adding an appropriate amount of a pH adjusting agent if necessary.
- the pH adjuster may be either acid or alkali, and may be either an inorganic compound or an organic compound. As a result, the polishing rate of the object to be polished, the dispersibility of the abrasive grains, and the like can be controlled.
- a pH adjuster can be used individually or in mixture of 2 or more types.
- the pH adjusting agent known acids, bases, or salts thereof can be used.
- the acid include, for example, 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, cit
- the base that can be used as the pH adjusting agent include alkali metal hydroxides or salts, Group 2 element hydroxides or salts, quaternary ammonium hydroxide or salts thereof, ammonia, amines, and the like.
- the alkali metal include potassium and sodium.
- Specific examples of the salt include carbonate, hydrogen carbonate, sulfate, acetate, and the like.
- Specific examples of the quaternary ammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium and the like.
- Examples of the quaternary ammonium hydroxide compound include quaternary ammonium hydroxide or a salt thereof, and specific examples include tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide.
- amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N- ( ⁇ -aminoethyl) ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, anhydrous piperazine Piperazine hexahydrate, 1- (2-aminoethyl) piperazine, N-methylpiperazine, guanidine and the like. These bases may be used individually by 1 type, and may be used in combination of 2 or more type.
- ammonia, ammonium salts, alkali metal hydroxides, alkali metal salts, quaternary ammonium hydroxide compounds, and amines are preferable. More preferably, ammonia, potassium compound, sodium hydroxide, quaternary ammonium hydroxide compound, ammonium hydrogen carbonate, ammonium carbonate, sodium hydrogen carbonate, and sodium carbonate are applied. Moreover, it is more preferable that the polishing composition contains a potassium compound as a base from the viewpoint of preventing metal contamination. Examples of the potassium compound include potassium hydroxide or salt, and specific examples include potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, potassium sulfate, potassium acetate, potassium chloride and the like.
- the addition amount of the pH adjusting agent is not particularly limited, and may be appropriately adjusted so that the polishing composition has a desired pH.
- the lower limit of the pH range of the polishing composition of the present invention is preferably 3 or more from the viewpoint of the dissolution of the polishing object progressing and the polishing rate by the polishing composition improving as the pH increases. More preferably, it is more preferably 5.
- the upper limit of the pH range is preferably less than 14 from the viewpoint of easy handling as the pH is lowered.
- the polishing composition of the present invention preferably contains a polishing accelerator.
- the polishing accelerator has an action of chemically etching the surface of the object to be polished, and improves the polishing rate of the object to be polished by the polishing composition.
- polishing accelerator examples include inorganic acids or salts thereof, organic acids or salts thereof, nitrile compounds, amino acids, and chelating agents. These polishing accelerators may be used alone or in combination of two or more.
- the polishing accelerator may be a commercially available product or a synthetic product.
- the inorganic acid include sulfuric acid, nitric acid, carbonic acid, boric acid, tetrafluoroboric acid, hypophosphorous acid, phosphorous acid, phosphoric acid, pyrophosphoric acid and the like.
- organic acid examples include, for example, 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, Examples thereof include monovalent carboxylic acids such as n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, lactic acid, glycolic acid, glyceric acid, benzoic acid, and salicylic acid. Also, sulfonic acids such as methanesulfonic acid, ethanesulfonic acid and isethionic acid can be used.
- the inorganic acid or organic acid salt may be used.
- a salt of a weak acid and a strong base a salt of a strong acid and a weak base, or a salt of a weak acid and a weak base
- a pH buffering action can be expected.
- salts include, for example, potassium chloride, sodium sulfate, potassium nitrate, potassium carbonate, potassium tetrafluoroborate, potassium pyrophosphate, potassium oxalate, trisodium citrate, (+)-potassium tartrate, hexafluoro A potassium phosphate etc. are mentioned.
- nitrile compounds include acetonitrile, aminoacetonitrile, propionitrile, butyronitrile, isobutyronitrile, benzonitrile, glutaronitrile, methoxyacetonitrile, and the like.
- amino acids include glycine, ⁇ -alanine, ⁇ -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, ⁇ - (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,
- the chelating agent include N, N, N-trimethylenephosphonic acid, ethylenediamine-N, N, N ′, N′-tetramethylenesulfonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1 -Hydroxyethylidene-1,1-diphosphonic acid, 1,2-dihydroxybenzene-4,6-disulfonic acid and the like.
- At least one selected from the group consisting of an inorganic acid or a salt thereof, a carboxylic acid or a salt thereof, and a nitrile compound is preferable, from the viewpoint of stability of a complex structure with a metal compound contained in a polishing object.
- An inorganic acid or a salt thereof is more preferable.
- the lower limit of the content (concentration) of the polishing accelerator in the polishing composition is not particularly limited because the effect is exhibited even with a small amount, but is preferably 0.001 g / L or more, and 0.01 g / L. It is more preferably L or more, and further preferably 1 g / L or more. As the content increases, the polishing rate is further improved. Further, the upper limit of the content (concentration) of the polishing accelerator in the polishing composition is preferably 200 g / L or less, more preferably 150 g / L or less, and further preferably 100 g / L or less. preferable. As the content decreases, the dissolution of cobalt is prevented and the step resolution is improved.
- the polishing composition of the present invention may contain a metal anticorrosive.
- a metal anticorrosive By adding a metal anticorrosive to the polishing composition, it is possible to suppress deterioration of the surface condition such as surface roughness of the polishing surface by preventing dissolution of the metal, particularly dissolution of the layer containing copper.
- the usable metal anticorrosive agent is not particularly limited, but is preferably a heterocyclic compound.
- 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.
- Nitrogen-containing heterocyclic compounds such as cinnoline compounds, buteridine compounds, and furazane compounds.
- 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. As the content of the metal anticorrosive increases, the dissolution of the metal can be prevented and the level difference elimination can be improved. Further, the upper limit of the content of the metal anticorrosive in the polishing composition is preferably 10 g / L or less, more preferably 5 g / L or less, and further preferably 2 g / L or less. As the content of the metal anticorrosive decreases, the polishing rate increases.
- the polishing composition of the present invention preferably contains a surfactant.
- the surfactant can suppress dishing on the polished surface after polishing.
- the surfactant may be any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.
- anionic surfactant examples include polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl sulfate ester, alkyl sulfate ester, polyoxyethylene alkyl sulfate, alkyl sulfate, alkylbenzene sulfonic acid, alkyl phosphate ester, polyoxyethylene ester Ethylene alkyl phosphate ester, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthalene sulfonic acid, alkyl diphenyl ether disulfonic acid, salts thereof and the like are included.
- cationic surfactant examples include alkyltrimethylammonium salt, alkyldimethylammonium salt, alkylbenzyldimethylammonium salt, alkylamine salt and the like.
- amphoteric surfactants include alkyl betaines and alkyl amine oxides.
- nonionic surfactants include polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, alkyl alkanolamides, and the like. included. These surfactants may be used individually by 1 type, and may be used in combination of 2 or more type.
- a 1 to A 3 are each independently a hydrogen atom, a methyl group, an ethyl group or a polyoxyalkylene aryl ether group, provided that at least one of A 1 to A 3 Is a polyoxyalkylene aryl ether group, and the polyoxyalkylene aryl ether group is
- Ar represents an aryl group having 6 to 20 carbon atoms that may have a substituent
- E represents an alkylene group having 1 to 3 carbon atoms
- n represents 1 to 100.
- a surfactant represented by the formula is also preferably used.
- the surfactant represented by the above formula 1 contains a phosphoric acid skeleton and has a chelating effect on metal wiring (for example, copper, copper alloy), but has a polyoxyalkylene aryl ether group. Then, the chelating ability is lowered and adjusted to an appropriate chelating ability. As a result, it is possible to prevent dishing of the metal wiring while expressing the polishing rate of the metal wiring.
- a 1 to A 3 are each independently a hydrogen atom, a methyl group, an ethyl group or a polyoxyalkylene aryl ether group, provided that at least one of A 1 to A 3 is a poly An oxyalkylene aryl ether group; However, one of A 1 to A 3 is preferably a polyoxyalkylene aryl ether group from the viewpoint of the effect of suppressing etching of the metal surface. In view of dispersibility of the surfactant in the polishing composition, at least one of A 1 to A 3 is preferably a hydrogen atom.
- a 1 ⁇ A 3 one is a polyoxyalkylene aryl ether group having the formula 3 described below as Ar, balance are hydrogen atoms And preferred.
- the compound of Formula 1 may be 1 type, and 2 or more types may be sufficient as it.
- the surfactant represented by the above formula 1 may be in the form of a salt.
- the salt include monovalent or divalent metal salts, ammonium salts, and amine salts.
- the monovalent or divalent metal salt include lithium salt, sodium salt, potassium salt, magnesium salt, calcium salt and the like.
- amine salts and potassium salts are preferred from the viewpoint of metal impurities in the polishing composition for semiconductors.
- specific examples of the amine salt include triethanolamine and trimethanolamine, and triethanolamine is preferable from the viewpoint of polishing performance.
- the salt form refers to a form in which when one or more of A 1 to A 3 are hydrogen atoms, some or all of the hydrogen atoms are substituted with the salts listed above.
- Ar represents an aryl group having 6 to 20 carbon atoms that may have a substituent
- E represents an alkylene group having 1 to 3 carbon atoms
- n represents 1 to 100. Indicated.
- the aryl group has 6 to 20 carbon atoms, preferably 6 to 15 carbon atoms, more preferably 6 to 13 carbon atoms, and still more preferably 6 carbon atoms. ⁇ 8.
- the carbon number is in such a range, the desired effect of the present invention can be efficiently achieved.
- examples thereof include a phenyl group, a naphthyl group, and an anthracenyl group. In particular, when the phenyl group is used, the desired effect of the present invention can be efficiently achieved. Can do.
- Ar is represented by the following formula 3:
- each of R 1 to R 5 is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 21 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms. Indicated by
- the carbon number of the alkyl group in the substituted or unsubstituted alkyl group having 1 to 21 carbon atoms is more preferably 1 to 18, further preferably 1 to 10, and still more preferably. 1 to 5, particularly preferably 1 to 3.
- specific examples of the alkyl group are not particularly limited and may be linear or branched, and may be a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group.
- Pentyl group isopentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, 2-ethylhexyl group, tridecyl group, tetradecyl group , Pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group and the like.
- a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group are preferable, and a methyl group, an ethyl group, a propyl group, and an isopropyl group are more preferable.
- a methyl group and an ethyl group are preferred.
- the substituent in the substituted or unsubstituted alkyl group having 1 to 21 carbon atoms is preferably an aryl group or a halogen atom
- the aryl group is preferably a phenyl group or a naphthyl group
- the halogen atom is , Chlorine, bromine, iodine and the like are suitable.
- an aryl group is present as a substituent, the Cu surface becomes water-repellent when adsorbed on the Cu surface, and it becomes difficult for the abrasive grains and complexing agent to come into contact with the Cu surface. Can be prevented.
- the number of substitution by alkyl groups in R 1 to R 5 is preferably an integer of 1 to 3 from the viewpoint of dispersion stability.
- the substitution site of the alkyl group in R 1 to R 5 is not particularly limited, but from the viewpoint of realizing a high polishing rate, a low step, and suppressing etching, when the substitution number is 1, It is preferable that when the number of substitutions is 3, 2-position, 4-position and 6-position are preferred.
- An aryl group is a functional group or substituent derived from an aromatic hydrocarbon.
- the aryl group has 6 to 20 carbon atoms. From the viewpoint of dispersion stability, the aryl group preferably has 6 to 14 carbon atoms, more preferably 6 to 8 carbon atoms. There is no restriction
- the substituent in the substituted or unsubstituted aryl group having 6 to 20 carbon atoms an alkyl group having 1 to 21 carbon atoms, a halogen atom, or the like is preferable. The above examples are equally applicable to examples of alkyl groups having 1 to 21 carbon atoms.
- r is an integer of 1 to 5, and from the viewpoint of dispersion stability, more preferably an integer of 1 to 3;
- s is an integer of 1 to 5, and is preferably an integer of 1 to 3, more preferably an integer of 1 to 2, and particularly preferably 1 from the viewpoint of dispersion stability.
- alkylene group having 1 to 3 carbon atoms in “E” in the above formula 2 are not particularly limited, and may be linear or branched.
- a methylene group, an ethylene group, A trimethylene group, a propylene group, etc. are mentioned, and when it is an ethylene group especially, the desired effect of the present invention mentioned above can be produced efficiently.
- N is 1 to 100, but is preferably an integer of 4 to 80, more preferably an integer of 8 to 50, from the viewpoint of dispersion stability.
- a surfactant represented by the following formulas 4 to 6 or a salt thereof is preferably used.
- a surfactant that is a compound represented by Formula 6 or a salt thereof is suitable, and considering coexistence with polishing performance, A surfactant which is a compound represented by Formula 4 or a salt thereof is preferred.
- the phenyl group phenyl ether group
- the effect of high polishing rate and high etching suppression can be efficiently achieved.
- the number average molecular weight (Mn) of the surfactant having a polyoxyalkylene aryl ether group is preferably in the range of 200 to 100,000, and more preferably in the range of 300 to 5,000.
- the value of polystyrene conversion measured by GPC (gel permeation chromatography) method shall be employ
- the surfactant represented by the above formula 1 has a polyoxyalkylene aryl ether group
- a commercially available product may be purchased, and if necessary, referring to known knowledge or a combination thereof. Can also be synthesized.
- the lower limit of the content of the surfactant in the polishing composition is preferably 0.0001 g / L or more, and more preferably 0.001 g / L or more. As the surfactant content increases, dishing after polishing can be further reduced.
- the upper limit of the content of the surfactant in the polishing composition is preferably 20 g / L or less, and more preferably 10 g / L or less. As the surfactant content decreases, it is possible to suppress a decrease in the polishing rate.
- Preservatives and fungicides examples include 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one. And the like, isothiazoline-based preservatives such as paraoxybenzoates, and phenoxyethanol. These antiseptics and fungicides may be used alone or in combination of two or more.
- the polishing composition according to the present invention may contain a water-soluble polymer or a salt thereof.
- a water-soluble polymer or a salt thereof By adding a water-soluble polymer or a salt thereof, the dispersion stability of the polishing composition is improved, and the supply of the polishing composition can be stabilized by making the slurry concentration uniform. Moreover, the surface roughness of the object to be polished after polishing with the polishing composition can be further reduced.
- water-soluble polymer examples include, for example, polystyrene sulfonate, polyisoprene sulfonate, polyacrylate, polymaleic acid, polyitaconic acid, polyvinyl acetate, polyvinyl alcohol, polyglycerin, polyvinyl pyrrolidone, and isoprene sulfonic acid.
- acrylic acid copolymer polyvinylpyrrolidone-polyacrylic acid copolymer, polyvinylpyrrolidone-vinyl acetate copolymer, salt of naphthalenesulfonic acid formalin condensate, diallylamine hydrochloride-sulfur dioxide copolymer, carboxymethylcellulose, Examples include salts of carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, pullulan, chitosan, and chitosan salts. These water-soluble polymers may be used alone or in combination of two or more.
- the lower limit of the content of the water-soluble polymer or salt thereof in the polishing composition is preferably 0.0001 g / L or more, and more preferably 0.001 g / L or more. As the content of the water-soluble polymer or salt thereof increases, the surface roughness of the polishing surface by the polishing composition is further reduced.
- the upper limit of the content of the water-soluble polymer or salt thereof in the polishing composition is preferably 10 g / L or less, and more preferably 1 g / L or less. As the content of the water-soluble polymer or salt thereof decreases, the remaining amount of the water-soluble polymer or salt thereof on the polishing surface is reduced, and the cleaning efficiency is further improved.
- the method for producing the polishing composition of the present invention is not particularly limited, and for example, by stirring and mixing an oxidizing agent, a cobalt dissolution inhibitor, and other components as necessary in a dispersion medium or solvent such as water. Obtainable.
- the temperature at the time of mixing each component is not particularly limited, but is preferably 10 to 40 ° C., and may be heated to increase the dissolution rate. Further, the mixing time is not particularly limited.
- the polishing composition of the present invention is suitably used for polishing a polishing object having a layer containing copper and a layer containing cobalt. Therefore, this invention provides the grinding
- a polishing apparatus 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.
- 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.
- the rotation speed of the polishing surface plate is preferably 10 to 500 rpm, and the pressure applied to the object to be polished (polishing pressure) is preferably 0.1 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.
- the object to be polished is washed in running water, and water droplets adhering to the object to be polished are removed by a spin dryer or the like, and dried to obtain a polished object to be polished.
- a cobalt / copper patterning wafer (having a Ta layer as a barrier layer) was polished using the obtained polishing compositions (Examples 10 to 13 and Comparative Example 12) under the polishing conditions shown in Table 2 below.
- the polishing speed is determined by polishing the difference in thickness between the copper-containing layer and the cobalt-containing layer in the cobalt / copper patterning wafer before and after polishing, which is measured using a sheet resistance measuring instrument based on the DC 4 probe method. Determined by dividing by time. The results are shown in Table 3 below.
- a substrate (cobalt / copper patterning wafer having a barrier layer) having various sizes of lines and spaces (L / S) is polished under the polishing conditions shown in Table 2 until the barrier layer is exposed, and contains cobalt.
- the topography of the surface of the layer was measured with an atomic force microscope (AFM).
- Table 3 shows the observation results of the polishing rate, topography, and recess of the layer containing cobalt.
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Abstract
Description
まず、本発明に係る研磨対象物および半導体配線プロセスの一例を説明する。半導体配線プロセスは、通常、以下の工程を含む。
(酸化剤)
本発明に係る研磨用組成物は、酸化剤を含む。酸化剤は、銅を含む層に対する高い研磨速度を発現させる作用を有する。
本発明の研磨用組成物は、コバルト溶解抑制剤を含む。コバルト溶解抑制剤は、上述の通り、CMPを行う際、コバルトが溶解してしまうことを抑制する目的で添加される。本発明において、コバルト溶解抑制剤は、含窒素五員環構造を有する化合物、およびカルボキシル基を2つ以上有する化合物からなる群より選択される少なくとも1種である。
含窒素五員環構造を有する化合物としては、例えば、ピロール化合物、ピラゾール化合物、イミダゾール化合物、トリアゾール化合物、テトラゾール化合物、インドリジン化合物、インドール化合物、イソインドール化合物、インダゾール化合物、プリン化合物、チアゾール化合物、イソチアゾール化合物、オキサゾール化合物、イソオキサゾール化合物、フラザン化合物等が挙げられる。
カルボキシル基を2つ以上有するアミノカルボン酸の例としては、例えば、N,N’-ビス(2-ヒドロキシベンジル)エチレンジアミン-N,N’-二酢酸、ジエチレントリアミン五酢酸、トリエチレンテトラミン-N,N,N’’,N’’,N’’’,N’’’-六酢酸、ニトリロ三酢酸、N-(2-ヒドロキシエチル)イミノ二酢酸、N-(2-ヒドロキシエチル)エチレンジアミン-N,N’,N’-三酢酸、1,2-ジアミノプロパン-N,N,N’,N’-四酢酸、1,3-ジアミノプロパン-N,N,N’,N’-四酢酸、trans-シクロヘキサンジアミン-N,N,N’,N’-四酢酸、イミノ二酢酸、エチルエーテルジアミン四酢酸、グリコールエーテルジアミン四酢酸、エチレンジアミン四プロピオン酸、フェニレンジアミン四酢酸等が挙げられる。
本発明の研磨用組成物は、必要に応じて、砥粒、分散媒、溶媒、pH調整剤、研磨促進剤、金属防食剤、界面活性剤、防腐剤、防カビ剤、水溶性高分子等の他の成分をさらに含んでもよい。以下、上記他の成分について説明する。
本発明の研磨用組成物は砥粒を含むことが好ましい。砥粒は、研磨対象物を機械的に研磨する作用を有し、研磨用組成物による研磨対象物の研磨速度を向上させる。
≪表面修飾≫
砥粒は表面修飾されていてもよい。通常のコロイダルシリカは、酸性条件下でゼータ電位の値がゼロに近いために、酸性条件下ではシリカ粒子同士が互いに電気的に反発せず凝集を起こしやすい。これに対し、酸性条件下でもゼータ電位が比較的大きな負の値を有するように表面修飾された砥粒は、酸性条件下においても互いに強く反発して良好に分散する結果、研磨用組成物の保存安定性を向上させることになる。このような表面修飾砥粒は、例えば、アルミニウム、チタンまたはジルコニウムなどの金属あるいはそれらの酸化物を砥粒と混合して砥粒の表面にドープさせることにより得ることができる。
本発明に係る研磨用組成物に含まれる砥粒として、特に好ましいのは、有機酸を固定化したコロイダルシリカである。研磨用組成物中に含まれるコロイダルシリカの表面への有機酸の固定化は、例えばコロイダルシリカの表面に有機酸の官能基が化学的に結合することにより行われている。コロイダルシリカと有機酸とを単に共存させただけではコロイダルシリカへの有機酸を固定化することはできない。有機酸の一種であるスルホン酸をコロイダルシリカに固定化する場合、例えば、“Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups”, Chem. Commun. 246-247 (2003)に記載の方法で行うことができる。具体的には、3-メルカプトプロピルトリメトキシシラン等のチオール基を有するシランカップリング剤をコロイダルシリカにカップリングさせた後に過酸化水素でチオール基を酸化することにより、スルホン酸が表面に固定化されたコロイダルシリカを得ることができる。あるいは、カルボン酸をコロイダルシリカに固定化する場合、例えば、“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)に記載の方法で行うことができる。具体的には、光反応性2-ニトロベンジルエステルを含むシランカップリング剤をコロイダルシリカにカップリングさせた後に光照射することにより、カルボン酸が表面に固定化されたコロイダルシリカを得ることができる。
また、特開平4-214022号公報に開示されるような、塩基性アルミニウム塩または塩基性ジルコニウム塩を添加して製造したカチオン性シリカを砥粒として用いることもできる。
・平均一次粒子径
砥粒の平均一次粒子径の下限は、3nm以上であることが好ましく、5nm以上であることがより好ましく、7nm以上であることがさらに好ましい。また、砥粒の平均一次粒子径の上限は、200nm以下であることが好ましく、150nm以下であることがより好ましく、100nm以下であることがさらに好ましい。
砥粒の平均二次粒子径の下限は、10nm以上であることが好ましく、15nm以上であることがより好ましく、20nm以上であることがさらに好ましい。また、砥粒の平均二次粒子径の上限は、300nm以下であることが好ましく、260nm以下であることがより好ましく、220nm以下であることがさらに好ましい。このような範囲であれば、研磨用組成物による研磨対象物の研磨速度は向上し、また、研磨用組成物を用いて研磨した後の研磨対象物の表面に表面欠陥が生じるのをより抑えることができる。なお、ここでいう二次粒子とは、砥粒が研磨用組成物中で会合して形成する粒子をいい、この二次粒子の平均二次粒子径は、例えば動的光散乱法により測定することができる。
本発明の研磨用組成物中の砥粒の含有量の下限としては、研磨対象物の研磨速度の向上という観点から0.005質量%以上であることが好ましく、0.01質量%以上であることがより好ましく、0.1質量%以上であることがさらに好ましい。また、研磨用組成物中の砥粒の含有量の上限は、研磨用組成物のコスト低減、研磨後の研磨対象物の表面に表面欠陥が生じるのを抑制する観点から、50質量%以下であることが好ましく、30質量%以下であることがより好ましく、20質量%以下であることがさらに好ましい。
本発明の研磨用組成物は、通常各成分の分散または溶解のための分散媒または溶媒が用いられる。分散媒または溶媒としては有機溶媒、水が考えられるが、その中でも水を含むことが好ましい。他の成分の作用を阻害するという観点から、不純物をできる限り含有しない水が好ましい。具体的には、イオン交換樹脂にて不純物イオンを除去した後フィルタを通して異物を除去した純水や超純水、または蒸留水が好ましい。
本発明に係る研磨用組成物のpHは、必要によりpH調整剤を適量添加することにより、調整することができる。pH調整剤は酸およびアルカリのいずれであってもよく、また、無機化合物および有機化合物のいずれであってもよい。これにより、研磨対象物の研磨速度や砥粒の分散性等を制御することができる。pH調整剤は、単独でもまたは2種以上混合しても用いることができる。
本発明の研磨用組成物は研磨促進剤を含むことが好ましい。研磨促進剤は、研磨対象物の表面を化学的にエッチングする作用を有し、研磨用組成物による研磨対象物の研磨速度を向上させる。
本発明の研磨用組成物は、金属防食剤を含んでもよい。研磨用組成物中に金属防食剤を加えることにより、金属の溶解、特に銅を含む層の溶解を防ぐことで研磨表面の面荒れ等の表面状態の悪化を抑えることができる。
本発明の研磨用組成物は界面活性剤を含むことが好ましい。界面活性剤は、研磨後の研磨表面にできるディッシングを抑制することができる。界面活性剤は、陰イオン性界面活性剤、陽イオン性界面活性剤、両性界面活性剤、および非イオン性界面活性剤のいずれであってもよい。
で示される界面活性剤も好適に用いられる。上記式1で示される界面活性剤は、リン酸骨格が含まれており、金属配線(例えば、銅、銅合金)に対してキレート効果を有しているが、ポリオキシアルキレンアリールエーテル基が存在すると、キレート能が低下して適度なキレート能に調整される。その結果、金属配線の研磨レートを発現させつつ、金属配線のディッシングを防ぐことができる。
本発明に係る研磨用組成物に添加し得る防腐剤および防カビ剤としては、例えば、2-メチル-4-イソチアゾリン-3-オンや5-クロロ-2-メチル-4-イソチアゾリン-3-オン等のイソチアゾリン系防腐剤、パラオキシ安息香酸エステル類、およびフェノキシエタノール等が挙げられる。これら防腐剤および防カビ剤は、単独でもまたは2種以上混合して用いてもよい。
本発明に係る研磨用組成物は、水溶性高分子またはその塩を含んでもよい。水溶性高分子またはその塩を添加することによって研磨用組成物の分散安定性が向上し、スラリー濃度の均一化により研磨用組成物の供給の安定化が可能になる。また、研磨用組成物を用いて研磨した後の研磨対象物の表面粗さをより低減させることができる。
本発明の研磨用組成物の製造方法は、特に制限されず、例えば、酸化剤、コバルト溶解抑制剤、および必要に応じて他の成分を水などの分散媒または溶媒中で攪拌混合することにより得ることができる。
上述のように、本発明の研磨用組成物は、銅を含む層とコバルトを含む層とを有する研磨対象物の研磨に好適に用いられる。よって、本発明は、銅を含む層とコバルトを含む層とを有する研磨対象物を本発明の研磨用組成物で研磨する研磨方法を提供する。本発明の効果をより効率よく得るために、銅を含む層とコバルトを含む層とを同時に研磨することが好ましい。また、本発明は、銅を含む層とコバルトを含む層とを有する研磨対象物を上記研磨方法で研磨する工程を含む基板の製造方法を提供する。
酸化剤として過酸化水素水(濃度:31質量%)30g/L(過酸化水素として研磨用組成物中に9.3g/L)、コバルト溶解抑制剤として下記表1に示す化合物を0.1mol/L、および研磨促進剤としてグリシン 10g/Lの含有量とそれぞれなるように水中で攪拌混合し(混合温度:約25℃、混合時間:約10分)、研磨用組成物を調製した。
砥粒としてコロイダルシリカ(平均一次粒子径:10nm、平均二次粒子径:28nm)3g/L、酸化剤として過酸化水素 10g/L、界面活性剤としてポリオキシエチレンアルキルエーテル 0.5g/Lおよび上記式4で示されるトリスチリルフェニルエーテルEOリン酸エステル(ローディア日華株式会社製、SOPROPHOR(登録商標)3D33)0.2g/L、下記表3に示すコバルト溶解抑制剤を0.1mol/L、研磨促進剤としてグリシン 10g/Lを、それぞれ記載の含有量となるように水中で攪拌混合(混合温度:約25℃、混合時間:約10分)した。さらに、pH調整剤として水酸化カリウムを用い、pHを7.0に調整することで研磨用組成物を得た。得られた研磨用組成物のpHは、pHメータにより25℃で確認した。
上記表2に記載の研磨条件で、種々の大きさのラインアンドスペース(L/S)を有する基板(バリア層を有するコバルト/銅パターニングウェハ)をバリア層が露出するまで研磨し、コバルトを含む層の表面のトポグラフィーを原子間力顕微鏡(AFM)で測定した。
実施例10~13、および比較例12の研磨用組成物を用いてコバルト/銅パターニングウェハを研磨した後のパターンの断面を、走査型電子顕微鏡により観察した。
Claims (9)
- 銅を含む層とコバルトを含む層とを有する研磨対象物を研磨する用途で用いられる研磨用組成物であって、
酸化剤と、
含窒素5員環構造を有する化合物、およびカルボキシル基を2つ以上有するアミノカルボン酸からなる群より選択される少なくとも1種のコバルト溶解抑制剤と、
を含有する、研磨用組成物。 - 前記含窒素5員環構造を有する化合物が、1H-ベンゾトリアゾール、5-メチル-1H-ベンゾトリアゾール、1H-イミダゾール、および1H-テトラゾールからなる群より選択される少なくとも1種である、請求項1に記載の研磨用組成物。
- 前記アミノカルボン酸が、ジエチレントリアミン五酢酸、トリエチレンテトラミン-N,N,N’’,N’’,N’’’,N’’’-六酢酸、ニトリロ三酢酸、N-(2-ヒドロキシエチル)イミノ二酢酸、およびN-(2-ヒドロキシエチル)エチレンジアミン-N,N’,N’-三酢酸からなる群より選択される少なくとも1種である、請求項1に記載の研磨用組成物。
- 研磨促進剤をさらに含有する、請求項1~3のいずれか1項に記載の研磨用組成物。
- 界面活性剤をさらに含有する、請求項1~4のいずれか1項に記載の研磨用組成物。
- 酸化剤と、含窒素5員環構造を有する化合物、およびカルボキシル基を2つ以上有するアミノカルボン酸からなる群より選択される少なくとも1種のコバルト溶解抑制剤と、を混合することを含む、研磨用組成物の製造方法。
- 銅を含む層とコバルトを含む層とを有する研磨対象物を研磨する方法であって、
請求項1~5のいずれか1項に記載の研磨用組成物、または請求項6に記載の製造方法により得られる研磨用組成物を用いて、前記銅を含む層と前記コバルトを含む層とを同時に研磨することを含む、研磨方法。 - 銅を含む層とコバルトを含む層とを有する研磨対象物を請求項7に記載の研磨方法で研磨する工程を含む、基板の製造方法。
- 請求項8に記載の製造方法により得られる、基板。
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| KR20190106679A (ko) * | 2018-03-07 | 2019-09-18 | 가부시키가이샤 후지미인코퍼레이티드 | 연마용 조성물 |
| WO2019239555A1 (ja) * | 2018-06-14 | 2019-12-19 | 日立化成株式会社 | 研磨液及び研磨方法 |
| US11043396B2 (en) * | 2018-07-31 | 2021-06-22 | Taiwan Semiconductor Manufacturing Company, Ltd. | Chemical mechanical polish slurry and method of manufacture |
| KR102082922B1 (ko) | 2019-03-04 | 2020-04-23 | 영창케미칼 주식회사 | 실리콘산화막 연마용 슬러리 조성물 및 그를 이용한 연마방법 |
| KR20210076571A (ko) * | 2019-12-16 | 2021-06-24 | 주식회사 케이씨텍 | Sti 공정용 연마 슬러리 조성물 |
| JP2024541266A (ja) * | 2021-10-28 | 2024-11-08 | フジフイルム エレクトロニック マテリアルズ ユー.エス.エー., インコーポレイテッド | 研磨組成物及びその使用方法 |
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