WO2009104465A1 - Dispersion aqueuse pour polissage mécano-chimique et procédé de polissage mécano-chimique - Google Patents

Dispersion aqueuse pour polissage mécano-chimique et procédé de polissage mécano-chimique Download PDF

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WO2009104465A1
WO2009104465A1 PCT/JP2009/051582 JP2009051582W WO2009104465A1 WO 2009104465 A1 WO2009104465 A1 WO 2009104465A1 JP 2009051582 W JP2009051582 W JP 2009051582W WO 2009104465 A1 WO2009104465 A1 WO 2009104465A1
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chemical mechanical
mechanical polishing
aqueous dispersion
polishing
acid
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PCT/JP2009/051582
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English (en)
Japanese (ja)
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裕貴 仕田
崇文 清水
正俊 池田
翔 窪内
陽介 柴田
民智明 安藤
和一 内倉
彰浩 竹村
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Jsr株式会社
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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]
    • 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
    • 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
    • C09K3/1454—Abrasive powders, suspensions and pastes for polishing
    • C09K3/1463—Aqueous liquid suspensions

Definitions

  • the present invention relates to a chemical mechanical polishing aqueous dispersion and a chemical mechanical polishing method.
  • low dielectric constant interlayer insulating film (hereinafter also referred to as “low dielectric constant insulating film”) has been studied in order to prevent an increase in signal delay due to the multilayer wiring of semiconductor devices.
  • a low dielectric constant insulating film for example, materials described in Japanese Patent Application Laid-Open Nos. 2001-308089 and 2001-298023 have been studied.
  • the low dielectric constant insulating film as described above is used as the interlayer insulating film, high electrical conductivity is required for the wiring material, and thus copper or copper alloy is generally used.
  • the first polishing step it is required to selectively polish only the wiring material at a high speed.
  • the end of the first polishing step when another type of material film such as a barrier metal film is exposed, it is extremely difficult to suppress dishing and erosion of the wiring portion while maintaining a high polishing rate for the wiring material. It is difficult to.
  • only the polishing rate is increased, it may be achieved by increasing the applied pressure during polishing and increasing the frictional force applied to the wafer, but dishing and erosion of the wiring part is also accompanied by an increase in the polishing rate.
  • the approach from the polishing method was limited because it deteriorated.
  • the second polishing step a characteristic of smoothly polishing the surface to be polished is required. Therefore, in order to further improve the flatness of the surface to be polished in the second polishing step, a design change of the semiconductor device structure has been studied. Specifically, when using a low dielectric constant insulating film having low mechanical strength, (1) surface defects called peeling or scratches are generated on the surface to be polished by chemical mechanical polishing, and (2) fine When polishing a wafer having a wiring structure, the polishing rate of the low dielectric constant insulating film is remarkably increased, so that it is impossible to obtain a flat and highly accurate finished surface.
  • the chemical mechanical polishing aqueous dispersion is generally composed of abrasive grains and additive components.
  • the development of an aqueous dispersion for chemical mechanical polishing has mainly focused on the combination of additive components.
  • Studies have been made to improve the polishing characteristics by controlling the properties of the grains.
  • An object of the present invention is to reduce a polishing rate for a low dielectric constant insulating film without causing defects in a metal film or a low dielectric constant insulating film, and to achieve a high polishing rate and a high polishing rate for an interlayer insulating film (cap layer) such as a TEOS film.
  • an aqueous dispersion for chemical mechanical polishing that has flattening characteristics, has less metal contamination of the wafer, and can suppress surface defects such as dishing, erosion, scratches or fangs, and a chemical mechanical polishing method using the same. .
  • Another object of the present invention is to have a high polishing rate and a high polishing selectivity for a copper film without causing defects in the metal film and the low dielectric constant insulating film even under normal pressure conditions, An aqueous dispersion for chemical mechanical polishing with less metal contamination and a chemical mechanical polishing method using the same are provided.
  • “fang” is a phenomenon that occurs particularly when the metal film is made of copper or a copper alloy, and includes a region containing copper or copper alloy fine wiring and a copper or copper alloy fine wiring. This refers to a polishing defect in which dishing or erosion is locally generated by chemical mechanical polishing at the interface with a region (field portion) that does not contain.
  • fangs One factor causing fangs is that the components contained in the chemical mechanical polishing aqueous dispersion are non-uniform at the interface between the region containing fine copper or copper alloy wiring and the region not containing copper or copper alloy fine wiring. It is considered that the vicinity of the interface is excessively polished. For example, if the abrasive grain component contained in the chemical mechanical polishing aqueous dispersion is present at a high concentration in the vicinity of the interface, the polishing rate at the interface is locally increased and excessively polished. Thus, when it grind
  • the object to be processed 100 includes an insulating film 12 having a wiring recess 20 such as a groove formed on a substrate 10, the surface of the insulating film 12, and the bottom and inner wall surfaces of the wiring recess 20.
  • the barrier metal film 14 provided so as to cover the wiring recess 20 is filled, and a film 16 made of copper or a copper alloy formed on the barrier metal film 14 is sequentially laminated.
  • the to-be-processed object 100 contains the area
  • FIG. 2 shows a state after the film 16 made of copper or copper alloy is polished by chemical mechanical polishing until the barrier metal film 14 appears on the surface. At this stage, fangs have not yet occurred.
  • FIG. 3 shows a state after the barrier metal film 14 is cut and chemical mechanical polishing is performed until the insulating film 12 appears on the surface.
  • fine scratches 26 may be generated at the interface between the region 22 including the fine wiring of copper or copper alloy and the region 24 not including the fine wiring of copper or copper alloy.
  • FIG. 4 shows a state after further performing chemical mechanical polishing and cutting the insulating film 12. At this stage, the fine scratch 26 becomes a groove-like scratch fang 28.
  • This fang may be a defect as a semiconductor device, which is not preferable from the viewpoint of reducing the yield of semiconductor device manufacturing.
  • the first chemical mechanical polishing aqueous dispersion according to the present invention comprises: (A) silica particles; (B1) an organic acid, An aqueous dispersion for chemical mechanical polishing containing The (A) silica particles have the following chemical properties.
  • the silanol group density calculated from the specific surface area measured using the BET method and the amount of silanol groups measured by titration is 1.0 to 3.0 / nm 2 .
  • the first chemical mechanical polishing aqueous dispersion according to the present invention may have the following aspects.
  • the (B1) organic acid can be an organic acid having two or more carboxyl groups.
  • Acid dissociation index pKa of the organic acid having two or more carboxyl groups at 25 ° C. (However, in the case of an organic acid having two carboxyl groups, the pKa of the second carboxyl group is changed to 3 or more carboxyl groups. In the case of the organic acid having, the pKa of the third carboxyl group is used as an index.) Can be 5.0 or more.
  • the organic acid having two or more carboxyl groups may be at least one selected from maleic acid, malonic acid, and citric acid.
  • (C1) a nonionic surfactant can be contained.
  • the (C1) nonionic surfactant may have at least one acetylene group.
  • the (C1) nonionic surfactant may be a compound represented by the following general formula (1).
  • n and n are each independently an integer of 1 or more and satisfy m + n ⁇ 50.
  • (D1) a water-soluble polymer having a weight average molecular weight of 50,000 to 5,000,000 can be contained.
  • the water-soluble polymer may be a polycarboxylic acid.
  • the polycarboxylic acid may be poly (meth) acrylic acid.
  • the content of the water-soluble polymer (D1) can be 0.001% by mass to 1.0% by mass with respect to the total mass of the chemical mechanical polishing aqueous dispersion.
  • the ratio (Rmax / Rmin) of the major axis (Rmax) and minor axis (Rmin) of the silica particles can be 1.0 to 1.5.
  • the average particle size calculated from the specific surface area of the (A) silica particles measured using the BET method can be 10 nm to 100 nm.
  • PH can be 6-12.
  • the second chemical mechanical polishing aqueous dispersion according to the present invention comprises: (A) silica particles; (B2) an amino acid; An aqueous dispersion for chemical mechanical polishing for polishing a copper film containing
  • the (A) silica particles have the following chemical properties.
  • the silanol group density calculated from the specific surface area measured using the BET method and the amount of silanol groups measured by titration is 1.0 to 3.0 / nm 2 .
  • the second chemical mechanical polishing aqueous dispersion according to the present invention can have the following aspects.
  • the (B2) amino acid may be at least one selected from glycine, alanine and histidine.
  • an organic acid having a nitrogen-containing heterocyclic ring and a carboxyl group can be contained.
  • (C2) an anionic surfactant can be contained.
  • the (C2) anionic surfactant can have a carboxyl group, a sulfonic acid group, a phosphoric acid group, and at least one functional group selected from ammonium salts and metal salts of these functional groups.
  • the (C2) anionic surfactant is an alkyl sulfate, an alkyl ether sulfate, an alkyl ether carboxylate, an alkyl benzene sulfonate, an alpha sulfo fatty acid ester, an alkyl polyoxyethylene sulfate, an alkyl phosphate, It can be one selected from monoalkyl phosphate esters, naphthalene sulfonates, alpha olefin sulfonates, alkane sulfonates and alkenyl succinates.
  • the (C2) anionic surfactant may be a compound represented by the following general formula (2).
  • R 1 and R 2 each independently represent a hydrogen atom, a metal atom, or a substituted or unsubstituted alkyl group
  • R 3 represents a substituted or unsubstituted alkenyl group or sulfonic acid group.
  • —SO 3 X where X represents a hydrogen ion, an ammonium ion or a metal ion.
  • (D2) a water-soluble polymer having properties as a Lewis base having a weight average molecular weight of 10,000 to 1,500,000 can be contained.
  • the water-soluble polymer may have at least one molecular structure selected from a nitrogen-containing heterocyclic ring and a cationic functional group.
  • the (D2) water-soluble polymer may be a homopolymer having a nitrogen-containing monomer as a repeating unit or a copolymer containing a nitrogen-containing monomer as a repeating unit.
  • the nitrogen-containing monomers include N-vinylpyrrolidone, (meth) acrylamide, N-methylolacrylamide, N-2-hydroxyethylacrylamide, acryloylmorpholine, N, N-dimethylaminopropylacrylamide and its diethyl sulfate, N, N -Dimethylacrylamide, N-isopropylacrylamide, N-vinylacetamide, N, N-dimethylaminoethylmethacrylic acid and its diethyl sulfate salt, and at least one selected from N-vinylformamide.
  • the ratio (Rmax / Rmin) of the major axis (Rmax) and minor axis (Rmin) of the silica particles can be 1.0 to 1.5.
  • the average particle size calculated from the specific surface area of the (A) silica particles measured using the BET method can be 10 nm to 100 nm.
  • PH can be 6-12.
  • the (A) silica particles may further have the following chemical properties.
  • a polished surface of a semiconductor device having at least one selected from a metal film, a barrier metal film, and an insulating film is formed using the first chemical mechanical polishing aqueous dispersion. It is characterized by polishing.
  • the polishing rate for the low dielectric constant insulating film is reduced, and both the high polishing rate and the high planarization characteristic for the interlayer insulating film (cap layer) such as the TEOS film are achieved. be able to. Further, according to the first chemical mechanical polishing aqueous dispersion, surface defects such as dishing, erosion, scratch or fang are suppressed without causing defects in the metal film or the low dielectric constant insulating film. Chemical mechanical polishing can be realized and metal contamination of the wafer can be reduced.
  • both a high polishing rate and a high polishing selectivity for the copper film can be achieved.
  • high-quality chemical mechanical polishing is realized without causing defects in the metal film and the low dielectric constant insulating film, even under normal pressure conditions, and Metal contamination of the wafer can be reduced.
  • FIG. 1 is a cross-sectional view for explaining a fang generation process.
  • FIG. 2 is a cross-sectional view for explaining a fang generation process.
  • FIG. 3 is a cross-sectional view for explaining a fang generation process.
  • FIG. 4 is a cross-sectional view for explaining a fang generation process.
  • FIG. 5 is a conceptual diagram schematically showing the major axis and minor axis of the silica particles.
  • FIG. 6 is a conceptual diagram schematically showing the major axis and minor axis of the silica particles.
  • FIG. 7 is a conceptual diagram schematically showing the major axis and minor axis of the silica particles.
  • FIG. 8 is a cross-sectional view showing an object to be processed used in the chemical mechanical polishing method according to the present embodiment.
  • FIG. 9 is a cross-sectional view for explaining a polishing step of the chemical mechanical polishing method according to the present embodiment.
  • FIG. 10 is a cross-sectional view for explaining a polishing step of the chemical mechanical polishing method according to the present embodiment.
  • FIG. 11 is a cross-sectional view for explaining a polishing step of the chemical mechanical polishing method according to the present embodiment.
  • a first chemical mechanical polishing aqueous dispersion according to the present embodiment includes (A) silica particles and (B1) an organic acid.
  • the (A) silica particle is “a silanol group density calculated from the specific surface area measured using the BET method and the amount of silanol groups measured by titration is 1.0 to 3.0. / Nm 2 ”.
  • silica particle in the present embodiment refers to a hydroxyl group directly bonded to a silicon atom on the surface of the silica particle, and the configuration or configuration is not particularly limited. Moreover, the production
  • the “silanol group density” in the present embodiment is the number of silanol groups per unit area on the surface of the silica particles, and serves as an index representing the electrical characteristics or chemical characteristics of the surface of the silica particles.
  • Silanol group the chemical mechanical polishing aqueous dispersion H + is taken by SiO of SiOH - because it exists stably in the state, it is normally negatively charged. Thereby, the electrical characteristics or chemical characteristics of the silica particles are developed.
  • the unit of silanol group density is expressed in units / nm 2 .
  • the silanol group density of (A) silica particles used in this embodiment is calculated from the surface area of silica particles measured using the BET method and the amount of silanol groups measured by titration.
  • the amount of silanol groups in the silica particles can be determined by a generally known potentiometric titration, an aqueous dispersion of silica particles as described in 2005 Precision Engineering Society Spring Conference Proceedings, p847-848, or It can be measured by titrating a chemical mechanical polishing aqueous dispersion in which silica particles are dispersed with a known base such as sodium hydroxide.
  • the silica particles (A) used in this embodiment have a silanol group density of 1.0 to 3.0 / nm 2 , more preferably 1.1 to 2.8 / nm 2 , and particularly preferably. Is 1.2 to 2.6 pieces / nm 2 .
  • the additive or component such as organic acid or water-soluble polymer contained in the chemical mechanical polishing aqueous dispersion is attracted or rejected due to the electrical or chemical characteristics of the silica particle surface. To do.
  • the additive component in the chemical mechanical polishing aqueous dispersion produces a minute concentration gradient around the silica particles, forming an optimal chemical mechanical polishing aqueous dispersion to achieve good polishing characteristics. Can be considered.
  • the components contained in the chemical mechanical polishing aqueous dispersion are localized in the vicinity of the interface between the region containing the fine wiring of copper or copper alloy and the region not containing the fine wiring of copper or copper alloy (field portion).
  • the silanol group density is within the above range, (A) a fine concentration gradient is generated around the silica particles, so that the generation of fangs is suppressed. You can also.
  • the chemical mechanical polishing aqueous dispersion is moderately stabilized by the interaction between the silica particles and other additives in the chemical mechanical polishing aqueous dispersion. It becomes possible to disperse stably in the interior, and no agglomeration that causes defects occurs during polishing. If the silanol group density exceeds 3.0 / nm 2 , such a balanced dispersion state cannot be obtained, which is not preferable because an insufficient polishing rate ratio and insufficient planarization characteristics are obtained.
  • the silanol group density is less than 1.0 / nm 2
  • the dispersion stability of the silica particles in the chemical mechanical polishing aqueous dispersion is inferior, the silica particles are aggregated, and the storage stability is deteriorated. It is not preferable.
  • the (A) silica particles used in the present embodiment may contain sodium in an amount of preferably 5 to 500 ppm, more preferably 10 to 400 ppm, and particularly preferably 15 to 300 ppm. Further, it can contain 100 to 20000 ppm of at least one selected from potassium and ammonium ions.
  • the content of potassium is preferably 100 to 20000 ppm, more preferably 500 to 15000 ppm, and particularly preferably 1000 to 10,000 ppm.
  • the ammonium ion content is preferably 100 to 20000 ppm, more preferably 200 to 10000 ppm, and particularly preferably 500 to 8000 ppm.
  • the total content of potassium and ammonium ions is preferably 100 to 20000 ppm, more preferably 500 to 15000 ppm, and particularly preferably May be in the range of 1000 to 10,000 ppm.
  • the pH of the silica particle dispersion may become too high and silica may dissolve.
  • at least one selected from potassium and ammonium ions is less than 100 ppm, the dispersion stability of the silica particles is lowered, and the silica particles are aggregated, thereby causing defects on the wafer. .
  • the content of sodium and potassium contained in the silica particles described above is a value quantified using ICP emission spectrometry (ICP-AES) or ICP mass spectrometry (ICP-MS).
  • ICP emission analyzer for example, “ICPE-9000 (manufactured by Shimadzu Corporation)” or the like can be used.
  • ICP mass spectrometer for example, “ICPM-8500 (manufactured by Shimadzu Corporation)”, “ELAN DRC PLUS (manufactured by Perkin Elmer)”, etc. can be used.
  • the content of ammonium ions contained in the silica particles described above is a value quantified using an ion chromatography method.
  • a non-suppressor ion chromatograph “HIS-NS (manufactured by Shimadzu Corporation)”, “ICS-1000 (manufactured by DIONEX)”, or the like can be used.
  • the sodium and potassium contained in the silica particles may be sodium ion and potassium ion, respectively.
  • content of the sodium, potassium, and ammonium ion described in this specification is the weight of sodium, potassium, and ammonium ions with respect to the weight of the silica particles.
  • the silica particles can be stably dispersed in the chemical mechanical polishing aqueous dispersion. Aggregation of silica particles that cause defects does not occur. Moreover, if it is in the said range, the metal contamination of the wafer after grinding
  • the average particle size calculated from the specific surface area of silica particles measured using the BET method is preferably 10 to 100 nm, more preferably 10 to 90 nm, and particularly preferably 10 to 80 nm.
  • the average particle diameter of the silica particles is within the above range, it is excellent in storage stability as a chemical mechanical polishing aqueous dispersion, and a smooth polished surface free from defects can be obtained.
  • the average particle size of the silica particles is less than the above range, the polishing rate for the interlayer insulating film (cap layer) such as the TEOS film becomes too small, which is not practical.
  • the average particle diameter of the silica particles exceeds the above range, the storage stability of the silica particles is inferior, which is not preferable.
  • the average particle diameter of the silica particles is calculated from the specific surface area measured using the BET method with a flow-type specific surface area automatic measuring device “micrometrics FlowSorb II 2300 (manufactured by Shimadzu Corporation)”, for example.
  • Average particle diameter (nm) 2727 / S (m 2 / g) (3)
  • all the average particle diameters of the silica particles in this specification are calculated based on the formula (3).
  • the ratio Rmax / Rmin of the major axis (Rmax) to the minor axis (Rmin) of the silica particles is preferably 1.0 to 1.5, more preferably 1.0 to 1.4, and particularly preferably 1.0 to 1. 3.
  • Rmax / Rmin is within the above range, a high polishing rate and high planarization characteristics can be exhibited without causing defects in the metal film or the insulating film. If Rmax / Rmin is greater than 1.5, defects after polishing occur, which is not preferable.
  • the major axis (Rmax) of the silica particles means the longest distance among the distances connecting the end portions of the images of one independent silica particle image taken by a transmission electron microscope.
  • the short diameter (Rmin) of the silica particles means the shortest distance among the distances connecting the end portions of the image of one independent silica particle image taken with a transmission electron microscope.
  • the major axis a of the elliptical shape is determined as the major axis (Rmax) of the silica particle
  • the elliptical minor axis b is determined as the minor axis (Rmin) of the silica particles.
  • the longest distance c connecting the end portions of the image is expressed as follows.
  • the longest diameter (Rmax) of the silica particles is determined, and the shortest distance d connecting the end portions of the image is determined as the short diameter (Rmin) of the silica particles.
  • Rmin short diameter
  • FIG. 7 when an image of one independent silica particle 30c photographed by a transmission electron microscope is an aggregate of three or more particles, the longest distance e connecting the end portions of the image is shown. Is the long diameter (Rmax) of the silica particles, and the shortest distance f connecting the end portions of the image is determined to be the short diameter (Rmin) of the silica particles.
  • the major axis and minor axis (Rmin) of 50 silica particles by measuring the major axis (Rmax) and minor axis (Rmin) of 50 silica particles by the above-described determination method, and calculating the average value of major axis (Rmax) and minor axis (Rmin), the major axis and The ratio to the minor axis (Rmax / Rmin) can be calculated and obtained.
  • the content of the silica particles (A) is preferably 1 to 20% by mass, more preferably 1 to 15% by mass with respect to the total mass of the chemical mechanical polishing aqueous dispersion at the time of use. Preferably, it is 1 to 10% by mass.
  • the content of the silica particles is less than the above range, a sufficient polishing rate cannot be obtained, which is not practical.
  • the content of the silica particles exceeds the above range, the cost increases and a stable chemical mechanical polishing aqueous dispersion may not be obtained.
  • the method for producing (A) silica particles used in the present embodiment is not particularly limited as long as silica particles in which the content of sodium, potassium and ammonium ions is within the above range are obtained, and a conventionally known method is applied. be able to. For example, it can be produced according to the method for producing a silica particle dispersion described in JP-A No. 2003-109921 and JP-A No. 2006-80406.
  • the alkali silicate aqueous solution include a sodium silicate aqueous solution, an ammonium silicate aqueous solution, a lithium silicate aqueous solution, and a potassium silicate aqueous solution that are generally known as water glass.
  • ammonium silicate include silicates made of ammonium hydroxide and tetramethylammonium hydroxide.
  • a sodium silicate aqueous solution containing 20 to 38% by mass of silica and having a SiO 2 / Na 2 O molar ratio of 2.0 to 3.8 is diluted with water, and diluted silica with a silica concentration of 2 to 5% by mass A sodium aqueous solution is used.
  • a dilute sodium silicate aqueous solution is passed through the hydrogen-type cation exchange resin layer to generate an active silicate aqueous solution from which most of the sodium ions have been removed.
  • This aqueous silicic acid solution is aged with heat while adjusting the pH to 7-9 with alkali, and grown to the desired particle size to produce colloidal silica particles.
  • an active silicic acid aqueous solution and small particles of colloidal silica are added in small amounts to prepare silica particles having a target particle size in the range of, for example, an average particle size of 10 to 100 nm.
  • the silica particle dispersion thus obtained is concentrated to increase the silica concentration to 20 to 30% by mass, and then passed again through the hydrogen-type cation exchange resin layer to remove most of the sodium ions and pH with an alkali.
  • silica particles containing 5 to 500 ppm of sodium and 100 to 20000 ppm of at least one selected from potassium and ammonium ions can be produced.
  • the content of sodium, potassium and ammonium ions contained in the silica particles is obtained by recovering the silica component by a known method such as centrifugation, ultrafiltration, etc., of the chemical mechanical aqueous dispersion containing the silica particles, It can be calculated by quantifying sodium, potassium and ammonium ions contained in the recovered silica component. Therefore, by analyzing the silica component recovered from the chemical mechanical polishing aqueous dispersion by the above method by a known method, it can be confirmed that the constituent requirements of the present invention are satisfied.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment contains (B1) an organic acid.
  • the (B1) organic acid is preferably an organic acid having two or more carboxyl groups. The following points are mentioned as an effect of the organic acid having two or more carboxyl groups.
  • polishing rate for a polishing target such as a copper film, a barrier metal film, and a TEOS film.
  • a water-soluble polymer described later the water-soluble polymer may cause a decrease in the polishing rate by protecting the surface to be polished. Even in such a case, the polishing rate for the polishing object can be increased by using an organic acid having two or more carboxyl groups in combination.
  • the dispersion stability of the silica particles can be enhanced by adsorbing to the surface of the silica particles. As a result, the storage stability of silica particles and the number of scratches estimated to be caused by aggregated particles can be greatly suppressed.
  • the organic acid having two or more carboxyl groups preferably has an acid dissociation index (pKa) at 25 ° C. in at least one dissociation stage of 5.0 or more.
  • the acid dissociation index (pKa) in the present invention is based on the pKa value of the second carboxyl group for an organic acid having two carboxyl groups, and the third carboxyl for an organic acid having three or more carboxyl groups.
  • the pKa value of the group is used as an index.
  • the acid dissociation index (pKa) is 5.0 or more, it has higher coordination ability to metal ions such as copper, tantalum, and titanium that are eluted into the chemical mechanical polishing aqueous dispersion by polishing. , Metal precipitation can be prevented.
  • the pH change in the polishing composition during the polishing process can be suppressed by buffering, and the (A) silica particles used in the present invention are suppressed from aggregating due to the pH change during the polishing process. can do.
  • the acid dissociation index (pKa) is less than 5.0, the above effect cannot be expected.
  • the acid dissociation index (pKa) is, for example, (a) The Journal of Physical Chemistry vol. 68, number 6, page 1560 (1964), (b) a method using an automatic potentiometric titrator (COM-980Win, etc.) manufactured by Hiranuma Sangyo Co., Ltd., and (c) The Chemical Society of Japan. It is possible to use the acid dissociation index described in the chemical manual of the edition (revised edition 3, June 25, 1984, published by Maruzen Co., Ltd.), (d) a database such as pKaBASE manufactured by Comprugrug, etc. it can.
  • Examples of organic acids having two or more carboxyl groups having an acid dissociation index (pKa) of 5.0 or more include the organic acids listed in Table 1.
  • the pKa values shown in Table 1 represent the pKa value of the second carboxyl group in the case of an organic acid having two carboxyl groups, and the pKa value of the third carboxyl group in an organic acid having three or more carboxyl groups. Represents a value.
  • organic acids having two or more carboxyl groups described in Table 1 maleic acid, malonic acid, and citric acid are more preferable, and maleic acid is particularly preferable.
  • Such an organic acid not only has a preferable pKa value, but also has a small steric hindrance due to its molecular structure, so that metal ions such as copper, tantalum, and titanium that are eluted into the chemical mechanical polishing aqueous dispersion by polishing. On the other hand, it has a high coordination ability and can prevent metal deposition.
  • the content of the organic acid (B1) is preferably 0.001 to 3.0% by mass, more preferably 0.01 to 2.0% by mass, based on the total mass of the chemical mechanical polishing aqueous dispersion. is there.
  • content of the (B1) organic acid is less than the above range, surface defects such as many scratches on the copper film may occur.
  • the silica particles may be aggregated and storage stability may be impaired.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment may contain (C1) a nonionic surfactant.
  • (C1) By adding a nonionic surfactant, the polishing rate for the interlayer insulating film can be controlled. That is, the polishing rate for the low dielectric constant insulating film can be suppressed, and the polishing rate for the cap layer such as the TEOS film can be increased.
  • Examples of the (C1) nonionic surfactant include a nonionic surfactant having at least one acetylene group such as an acetylene glycol ethylene oxide adduct, acetylene alcohol, a silicone surfactant, and an alkyl ether surfactant. , Polyvinyl alcohol, cyclodextrin, polyvinyl methyl ether, and hydroxyethyl cellulose. Although the said (C1) nonionic surfactant can be used individually by 1 type, you may use 2 or more types together.
  • nonionic surfactant having at least one acetylene group is preferable, and a nonionic surfactant represented by the following general formula (1) is more preferable.
  • n and n are each independently an integer of 1 or more and satisfy m + n ⁇ 50.
  • the hydrophilic / lipophilic balance can be adjusted by controlling m and n representing the number of added moles of ethylene oxide.
  • m and n are preferably 20 ⁇ m + n ⁇ 50, and more preferably 20 ⁇ m + n ⁇ 40.
  • the HLB value of the (C1) nonionic surfactant is preferably 5 to 20, and more preferably 8 to 17. If the HLB value is less than 5, the solubility in water is too small, which may not be suitable for use.
  • silica particles having a high content of sodium or potassium are used in the chemical mechanical polishing aqueous dispersion
  • sodium or potassium derived from the silica particles remains on the surface of the object to be polished even by a cleaning operation after polishing. It causes deterioration of the electrical characteristics of the device.
  • the (C1) nonionic surfactant is more easily formed on the surface of the low dielectric constant insulating film having relatively high hydrophobicity than the ionic surfactant. Presumed to tend to adsorb.
  • the adsorbed nonionic surfactant has a small molecular polarity and can be easily removed by a cleaning operation, it does not remain on the surface of the object to be polished and does not deteriorate the electrical characteristics of the device.
  • the content of the (C1) nonionic surfactant is preferably 0.001 to 1.0% by mass, more preferably 0.005 to 0.00%, based on the total mass of the chemical mechanical polishing aqueous dispersion. 5% by mass. (C1) When the content of the nonionic surfactant is within the above range, it is possible to achieve both an appropriate polishing rate and a good surface to be polished.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment may contain (D1) a water-soluble polymer having a weight average molecular weight of 50,000 to 5,000,000.
  • D1 a water-soluble polymer having a weight average molecular weight of 50,000 to 5,000,000.
  • a technique for adding a water-soluble polymer to an aqueous dispersion for chemical mechanical polishing is known, but in the present invention, from the viewpoint of reducing the polishing pressure exerted on the low dielectric constant insulating film, it is heavier than a commonly used water-soluble polymer. It is characterized in that a water-soluble polymer having a large average molecular weight is used.
  • the weight average molecular weight of the (D1) water-soluble polymer for example, a weight average molecular weight (Mw) in terms of polyethylene glycol measured by GPC (gel permeation chromatography) can be applied.
  • the weight average molecular weight (Mw) of the (D1) water-soluble polymer may be 50,000 to 5,000,000, preferably 200,000 to 5,000,000, more preferably 200,000 to 1,500,000.
  • the polishing rate for the interlayer insulating film (cap layer) can be increased while greatly reducing the polishing friction. Further, metal film dishing and metal film corrosion can be suppressed, and the metal film can be polished stably.
  • the weight average molecular weight When the weight average molecular weight is smaller than the lower limit, the polishing friction is reduced and the effect of suppressing metal film dishing and metal film corrosion is inferior. Further, when the weight average molecular weight is larger than the above upper limit, the stability of the chemical mechanical polishing aqueous dispersion is deteriorated, the viscosity of the aqueous dispersion is excessively increased, and the polishing liquid supply device is loaded. Problems can arise. In particular, when the weight average molecular weight of the (D1) water-soluble polymer exceeds 5 million, precipitation may occur due to aggregation of abrasive components when the aqueous dispersion is stored for a long period of time, and the storage temperature is slightly low. A water-soluble polymer may precipitate with the change, and it becomes difficult to obtain stable polishing characteristics.
  • water-soluble polymer (D1) examples include polyacrylic acid and salts thereof, polymethacrylic acid and salts thereof, polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylamide.
  • polymethacrylic acid having a carboxyl group in a repeating unit and a salt thereof, polyacrylic acid and a salt thereof, or a derivative thereof is preferable.
  • Polyacrylic acid and polymethacrylic acid are more preferable in that they do not affect the stability of the abrasive grains.
  • Polyacrylic acid is particularly preferable because it can impart an appropriate viscosity to the chemical mechanical polishing aqueous dispersion according to the present embodiment.
  • the content of the water-soluble polymer (D1) is preferably 0.001 to 1.0% by mass or less, more preferably 0.01 to 0.5%, based on the total mass of the chemical mechanical polishing aqueous dispersion. % By mass. (D1) When the content of the water-soluble polymer is less than the above range, the polishing rate for the low dielectric constant interlayer insulating film is not improved. On the other hand, when the content of the (D1) water-soluble polymer exceeds the above range, the silica particles may be aggregated.
  • the ratio of the content of the organic acid (B) to the content of the water-soluble polymer (D1) is preferably 1: 1 to 1:40, more preferably 1: 4 to 1:30. is there.
  • the ratio of the content of the (B) organic acid to the content of the (D1) water-soluble polymer is within the above range, it is possible to more surely achieve both an appropriate polishing rate and good flatness of the surface to be polished. Can be achieved.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment may contain an oxidizing agent as necessary.
  • the oxidizing agent include ammonium persulfate, potassium persulfate, hydrogen peroxide, ferric nitrate, diammonium cerium nitrate, iron sulfate, ozone, hypochlorous acid and its salts, potassium periodate, and peracetic acid. Is mentioned.
  • These oxidizing agents can be used alone or in combination of two or more. Of these oxidants, ammonium persulfate, potassium persulfate, and hydrogen peroxide are particularly preferred in view of oxidizing power, compatibility with the protective film, ease of handling, and the like.
  • the content of the oxidizing agent is preferably 0.05 to 5% by mass, more preferably 0.08 to 3% by mass, based on the total mass of the chemical mechanical polishing aqueous dispersion.
  • the content of the oxidizing agent is less than the above range, a sufficient polishing rate may not be ensured.
  • the content exceeds the above range, corrosion or dishing of a metal film such as a copper film may increase.
  • the pH of the chemical mechanical polishing aqueous dispersion according to this embodiment is preferably 6 to 12, more preferably 7 to 11.5, and particularly preferably 8 to 11.
  • the pH is less than 6, hydrogen bonds between silanol groups present on the surface of the silica particles cannot be broken, and the silica particles may be aggregated.
  • the pH is higher than 12, the basicity is too strong, which may cause wafer defects.
  • adjusting the pH for example, adjusting the pH by adding a pH adjuster represented by a basic salt such as potassium hydroxide, ammonia, ethylenediamine, TMAH (tetramethylammonium hydroxide), etc. Can do.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment is obtained by adding (A) silica particles, (B1) organic acid, and other additives directly to pure water. And can be prepared by mixing and stirring.
  • the chemical mechanical polishing aqueous dispersion thus obtained may be used as it is, but a chemical mechanical polishing aqueous dispersion containing each component in a high concentration (concentrated) is prepared and desired at the time of use. It may be used after diluting to a concentration of.
  • a plurality of liquids for example, two or three liquids
  • this may be supplied to the chemical mechanical polishing apparatus, or a plurality of liquids may be supplied individually to the chemical mechanical polishing apparatus.
  • a chemical mechanical polishing aqueous dispersion may be formed on a surface plate.
  • liquid (I) which is an aqueous dispersion containing water and (A) silica particles, and water (II) containing water and (B1) an organic acid are mixed.
  • a kit for preparing an aqueous dispersion can be mentioned.
  • the concentration of each component in the liquids (I) and (II) is particularly as long as the concentration of each component in the chemical mechanical polishing aqueous dispersion finally prepared by mixing these liquids is within the above range. It is not limited. For example, liquids (I) and (II) containing each component at a concentration higher than the concentration of the chemical mechanical polishing aqueous dispersion are prepared, and the liquids (I) and (II) are diluted as necessary at the time of use. Then, these are mixed to prepare a chemical mechanical polishing aqueous dispersion in which the concentration of each component is in the above range.
  • the liquids (I) and (II) when the liquids (I) and (II) are mixed at a weight ratio of 1: 1, the liquids (I) and (I) having a concentration twice the concentration of the chemical mechanical polishing aqueous dispersion. II) may be prepared. Moreover, after preparing liquid (I) and (II) of the density
  • the method and timing of mixing the liquid (I) and the liquid (II) are not particularly limited as long as the chemical mechanical polishing aqueous dispersion is formed at the time of polishing.
  • this may be supplied to a chemical mechanical polishing apparatus, or the liquid (I) and the liquid ( II) may be supplied independently to a chemical mechanical polishing apparatus and mixed on a surface plate.
  • the liquid (I) and the liquid (II) may be independently supplied to the chemical mechanical polishing apparatus and mixed in line in the apparatus, or a mixing tank is provided in the chemical mechanical polishing apparatus, You may mix.
  • a line mixer or the like may be used in order to obtain a more uniform chemical mechanical polishing aqueous dispersion.
  • the second chemical mechanical polishing aqueous dispersion according to the present invention is a chemical for polishing a copper film containing (A) silica particles and (B2) amino acids.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment contains (A) silica particles.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment contains (B2) an amino acid.
  • the (B2) amino acid is preferably at least one amino acid selected from glycine, alanine and histidine. These amino acids have a property of easily forming a coordinate bond with a copper ion, and form a coordinate bond with the surface of the copper film that is the surface to be polished. Thus, the surface roughness of the copper film can be suppressed and high flatness can be maintained, the affinity with copper and copper ions can be increased, and the polishing rate for the copper film can be promoted.
  • these amino acids can be easily coordinated with copper ions eluted into the slurry by polishing the copper film, and can prevent the precipitation of copper. As a result, it is possible to suppress the occurrence of polishing defects such as scratches on the copper film. Furthermore, these amino acids can efficiently capture unnecessary metals from the surface of the object to be polished after polishing, and can efficiently remove unnecessary metals from the surface of the object to be polished.
  • (D2) a water-soluble polymer, which will be described later, is used in combination, depending on the type and amount of addition, (D2) the water-soluble polymer adsorbs on the surface of the copper film to hinder polishing and reduce the polishing rate. May decrease.
  • the combined use of the amino acid (B2) has an effect of increasing the polishing rate of the copper film despite the addition of the water-soluble polymer. Moreover, by containing the (B2) amino acid, it is possible to promote the liberation into the solution by inhibiting the adsorption of sodium ions and potassium ions, which are crushed during polishing and eluted from the silica particles, onto the copper film surface. As a result, it can be effectively removed from the surface of the workpiece.
  • the content of the (B2) amino acid is preferably 0.001 to 3.0% by mass, more preferably 0.01 to 2.0% by mass, based on the total mass of the chemical mechanical polishing aqueous dispersion. . If the content of the (B2) amino acid is less than the above range, dishing of the copper film may occur. On the other hand, when the content of the (B2) amino acid exceeds the above range, the silica particles may aggregate.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment may contain (C2) an anionic surfactant.
  • (C2) an anionic surfactant when abrasive grains containing a large amount of sodium or potassium are used in the chemical mechanical polishing aqueous dispersion, sodium or potassium derived from the abrasive grains remains on the surface of the workpiece even after the cleaning operation after polishing. It has been considered that it causes deterioration of the electrical characteristics of the product, and its use has been avoided.
  • the (C2) anionic surfactant has a high affinity with copper and copper ions, and is preferentially adsorbed to copper rather than cations such as sodium ions and potassium ions to protect the surface.
  • the (C2) anionic surfactant can enhance the dispersion stability of the particles by adsorbing to the surface of the silica particles. As a result, the storage stability of the particles and the number of scratches estimated to be caused by the aggregated particles can be greatly suppressed.
  • the content of the (C2) anionic surfactant is preferably 0.0001 to 2.0% by mass, more preferably 0.0005 to 1.0%, based on the total mass of the chemical mechanical polishing aqueous dispersion. % By mass.
  • the content of the (C2) anionic surfactant is less than the above range, the protective action of the copper film surface is weakened, and as a result of corrosion and excessive etching, dishing and erosion may occur.
  • the content of the (C2) anionic surfactant exceeds the above range, the protective effect on the surface of the copper film becomes too strong, so that a sufficient polishing rate cannot be obtained and a copper residue (copper residue) is generated. There is. Moreover, there is a possibility that the silica particles are aggregated, resulting in practical problems such as intense foaming.
  • the (C2) anionic surfactant used in this embodiment has a carboxyl group, a sulfonic acid group, a phosphoric acid group, and at least one functional group selected from ammonium salts and metal salts of these functional groups. It is preferable.
  • Such (C2) anionic surfactants include fatty acid salts, alkyl sulfates, alkyl ether sulfate esters, alkyl ester carboxylates, alkyl benzene sulfonates, linear alkyl benzene sulfonates, alpha sulfo fatty acid ester salts, Alkyl polyoxyethylene sulfate, alkyl phosphate, monoalkyl phosphate ester salt, naphthalene sulfonate, alpha olefin sulfonate, alkane sulfonate, alkenyl succinate and the like can be mentioned.
  • alkylbenzene sulfonate linear alkylbenzene sulfonate, naphthalene sulfonate, and alkenyl succinate are more preferable.
  • anionic surfactants can be used singly or in combination of two or more.
  • the alkenyl succinate is particularly preferably a compound represented by the following general formula (2).
  • R 1 and R 2 are each independently a hydrogen atom, a metal atom, or a substituted or unsubstituted alkyl group.
  • R 1 and R 2 are alkyl groups, it is preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms.
  • R ⁇ 1 >, R ⁇ 2 > is a metal atom, it is preferable that it is an alkali metal atom, and it is more preferable that it is sodium or potassium.
  • R 3 represents a substituted or unsubstituted alkenyl group or sulfonic acid group (—SO 3 X).
  • R 3 is an alkenyl group, it is preferably a substituted or unsubstituted alkenyl group having 2 to 8 carbon atoms.
  • R 3 is a sulfonic acid group (—SO 3 X)
  • X is a hydrogen ion, an ammonium ion or a metal ion.
  • X is a metal ion, X is preferably a sodium ion or a potassium ion.
  • the compound represented by the general formula (2) has a particularly high effect of adsorbing on the surface of the copper film and protecting it from excessive etching and corrosion. Thereby, a smooth to-be-polished surface can be obtained.
  • the most effective combination of the (C2) anionic surfactant is a combination of ammonium dodecylbenzenesulfonate, which is an alkylbenzene sulfonate, and dipotassium alkenyl succinate, which is an alkenyl succinate. It has been clarified by studies by the authors.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment comprises (D2) a water-soluble polymer having properties as a Lewis base having a weight average molecular weight of 10,000 to 1,500,000. It is preferable to contain.
  • the (D2) water-soluble polymer has properties as a Lewis base, and is thus easily adsorbed (coordinated bond) on the surface of the copper film, and has an effect of suppressing the occurrence of dishing and corrosion of the copper film.
  • the (D2) water-soluble polymer preferably has at least one molecular structure selected from a nitrogen-containing heterocyclic ring and a cationic functional group.
  • a cationic functional group an amino group is preferable.
  • the nitrogen-containing heterocyclic ring and the cationic functional group have a property as a Lewis base, and are effectively adsorbed (coordinated bond) on the surface of the copper film, and are effective in suppressing the occurrence of dishing and corrosion of the copper film. is there.
  • it is preferable that the object to be polished is not contaminated.
  • the (D2) water-soluble polymer is more preferably a homopolymer having a nitrogen-containing monomer as a repeating unit or a copolymer containing a nitrogen-containing monomer as a repeating unit.
  • the nitrogen-containing monomer include N-vinylpyrrolidone, (meth) acrylamide, N-methylolacrylamide, N-2-hydroxyethylacrylamide, acryloylmorpholine, N, N-dimethylaminopropylacrylamide and its diethyl sulfate, N , N-dimethylacrylamide, N-isopropylacrylamide, N-vinylacetamide, N, N-dimethylaminoethyl methacrylic acid and its diethyl sulfate, and N-vinylformamide.
  • N-vinylpyrrolidone having a nitrogen-containing hetero five-membered ring in the molecular structure is particularly preferable.
  • N-Vinylpyrrolidone is easy to form a coordination bond with a copper ion via a nitrogen atom on the ring, enhances the affinity with copper and copper ion, and can be adsorbed on the surface of the copper film and appropriately protected. it can.
  • the (D2) water-soluble polymer is a copolymer containing a nitrogen-containing monomer as a repeating unit
  • the monomers are nitrogen-containing monomers, and at least one of the nitrogen-containing monomers is used.
  • the monomer that can be copolymerized with the nitrogen-containing monomer include acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, vinyl ethyl ether, divinylbenzene, vinyl acetate, and styrene.
  • the (D2) water-soluble polymer is preferably a homopolymer or copolymer having a cationic functional group.
  • it may be a homopolymer or copolymer (hereinafter also referred to as “specific polymer”) containing at least one of the repeating units represented by the following general formula (4) or (5).
  • R 1 represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms
  • R 2 represents a substituted or unsubstituted methylene group or 2 carbon atoms.
  • R 3 , R 4 and R 5 each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms
  • A represents a single bond or — .M representing O- or a -NH- - represents an anion).
  • A represents —O— or —NH—, and —O— is more preferable.
  • A is —NH—, the stability of the silica particles is lowered in relation to the content of the specific polymer or other components, and the silica particles may settle when stored for a long time. In such a case, redispersion processing such as ultrasonic dispersion is required before use, which increases the work burden.
  • the counter anion (M ⁇ ) is preferably a halide ion, an organic anion, or an inorganic anion. More preferred are hydroxide ion, chloride ion, bromide ion, NH 3 -conjugated base NH 2 ⁇ , alkyl sulfate ion, perchlorate ion, hydrogen sulfate ion, acetate ion and alkylbenzene sulfonate ion. Particularly preferred are chloride ion, alkyl sulfate ion, hydrogen sulfate ion, acetate ion and alkylbenzene sulfonate ion.
  • an organic anion metal contamination of the object to be polished can be avoided, and alkyl sulfate ions are particularly preferable from the viewpoint that they can be easily removed after completion of polishing.
  • the specific polymer is more preferably a copolymer containing a repeating unit represented by the following general formula (6).
  • the copolymer containing the repeating unit represented by the following general formula (6) is represented by the repeating unit represented by the general formula (4) and the general formula (5) and the following general formula (6).
  • the polymer may be a polymer in which the repeating units are randomly bonded, and the repeating unit represented by the general formula (4) and the general formula (5) and the repeating unit represented by the following general formula (6). It may be a block copolymer.
  • R 6 represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.
  • the repeating represented by the general formula (4) is used.
  • the number of moles of the unit is n and the number of moles of the repeating unit represented by the general formula (5) is m
  • the ratio is preferably 10/0 to 1/9, more preferably 10/0 to 2/8, particularly preferably 9/1 to 3/7. it can.
  • content of the repeating unit represented by the said General formula (4) and the repeating unit represented by the said General formula (5) is computed from the preparation amount of the monomer containing an amino group, and subsequent neutralization amount. It can also be measured by titrating a specific polymer with an acid or a base.
  • the specific polymer is a copolymer containing the repeating unit represented by the general formula (4) or (5) and the repeating unit represented by the general formula (6)
  • the number of moles of the repeating unit represented is q
  • the number of moles of the repeating unit represented by the general formula (4) or (5) is p
  • the molar ratio q / p is 9/1 to 1/9. Particularly good results can be obtained when it is within the range.
  • the amino group content of the specific polymer can be 0 to 0.100 mol / g, preferably 0.0005 to 0.010 mol / g, more preferably when calculated from the charged amount of monomer. Is 0.002 to 0.006 mol / g.
  • the cationic functional group content of the specific polymer can be 0 to 0.100 mol / g, preferably 0.0005 to 0.010 mol / g, as calculated from the monomer charge. More preferably, it is 0.002 to 0.006 mol / g.
  • the weight average molecular weight of the (D2) water-soluble polymer for example, a weight average molecular weight (Mw) in terms of polyethylene glycol measured by GPC (gel permeation chromatography) can be applied.
  • the weight average molecular weight (Mw) of the (D2) water-soluble polymer is 10,000 to 1,500,000, preferably 40,000 to 1,200,000.
  • polishing friction can be reduced, and dishing and corrosion of the copper film can be suppressed.
  • the copper film can be polished stably. If the weight average molecular weight is less than 10,000, the effect of reducing polishing friction is small, so that dishing and corrosion of the copper film may not be suppressed.
  • the weight average molecular weight exceeds 1,500,000
  • the dispersion stability of the silica particles is impaired, and the aggregated silica particles may increase the scratches on the copper film.
  • the viscosity of the chemical mechanical polishing aqueous dispersion may increase excessively, causing a problem such as a load on the slurry supply apparatus.
  • the occurrence of copper residue on the pattern becomes remarkable, which is not practical.
  • the content of the water-soluble polymer (D2) is preferably 0.001 to 1.0% by mass or less, more preferably 0.01 to 0.5% with respect to the total mass of the chemical mechanical polishing aqueous dispersion. % By mass.
  • the content of the (D2) water-soluble polymer is less than the above range, dishing of the copper film cannot be effectively suppressed.
  • the silica particles may be aggregated or the polishing rate may be reduced.
  • the (D2) water-soluble polymer has properties as a Lewis base, it can be efficiently coordinated to the surface of the copper film as the surface to be polished. Thereby, the surface of the copper film is effectively protected, the adsorption of sodium and potassium to the surface of the copper film can be suppressed, and the sodium and potassium can be easily removed from the surface of the copper film by washing. It becomes. Further, since the water-soluble polymer can be easily removed by a cleaning operation, it does not remain on the surface of the copper film and deteriorate the electrical characteristics of the device.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment can contain an organic acid having a nitrogen-containing heterocycle and a carboxyl group.
  • the organic acid having a nitrogen-containing heterocyclic ring and a carboxyl group can enhance the effect of the amino acid (B2) when used in combination with the amino acid (B2).
  • Examples of the organic acid having a nitrogen-containing heterocycle and a carboxyl group include organic acids containing a hetero 6-membered ring having at least one nitrogen atom, and organic acids containing a hetero compound consisting of a hetero 5-membered ring.
  • quinaldic acid quinolinic acid, quinoline-8-carboxylic acid, picolinic acid, xanthurenic acid, quinurenic acid, nicotinic acid, anthranilic acid and the like can be mentioned.
  • the content of the organic acid having a nitrogen-containing heterocycle and a carboxyl group is preferably 0.001 to 3.0% by mass, more preferably 0.01 to 3.0% by mass with respect to the total mass of the chemical mechanical polishing aqueous dispersion. 2.0% by mass. If the content of the organic acid having a nitrogen-containing heterocyclic ring and a carboxyl group is less than the above range, dishing of the copper film may be caused. On the other hand, when the content of the organic acid having a nitrogen-containing heterocyclic ring and a carboxyl group exceeds the above range, the silica particles may aggregate.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment may contain an oxidizing agent as required.
  • the oxidizing agent include ammonium persulfate, potassium persulfate, hydrogen peroxide, ferric nitrate, diammonium cerium nitrate, iron sulfate, ozone, hypochlorous acid and its salts, potassium periodate, and peracetic acid. Is mentioned.
  • These oxidizing agents can be used alone or in combination of two or more. Of these oxidants, ammonium persulfate, potassium persulfate, and hydrogen peroxide are particularly preferred in view of oxidizing power, compatibility with the protective film, ease of handling, and the like.
  • the content of the oxidizing agent is preferably 0.05 to 5% by mass, more preferably 0.08 to 3% by mass, based on the total mass of the chemical mechanical polishing aqueous dispersion.
  • the content of the oxidizing agent is less than the above range, a sufficient polishing rate for the copper film may not be obtained. On the other hand, if the above range is exceeded, dishing or corrosion of the copper film may occur.
  • the pH of the chemical mechanical polishing aqueous dispersion according to this embodiment is preferably 6 to 12, more preferably 7 to 11.5, and particularly preferably 8 to 11.
  • a pH adjuster represented by a basic salt such as potassium hydroxide, ammonia, ethylenediamine, TMAH (tetramethylammonium hydroxide), etc. Can do.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment can be suitably used for chemical mechanical polishing of an object to be processed (for example, a semiconductor device) having a copper film on its surface. That is, according to the chemical mechanical polishing aqueous dispersion according to this embodiment, (B2) containing amino acids suppresses the surface roughness of the copper film and maintains high flatness, while maintaining affinity with copper and copper ions. And the polishing rate for the copper film can be promoted. Thereby, the copper film on the surface can be polished at high speed and selectively without causing defects in the copper film and the low dielectric constant insulating film even under normal polishing pressure conditions. Moreover, according to the chemical mechanical polishing aqueous dispersion according to this embodiment, metal contamination of the wafer can be reduced.
  • the chemical mechanical polishing aqueous dispersion according to the present embodiment uses, for example, a damascene method in which a semiconductor device using a low dielectric constant insulating film as an insulating film and copper or a copper alloy as a wiring material is used.
  • the present invention can be applied to a process (first polishing process) in which the copper film on the barrier metal film is removed by chemical mechanical polishing.
  • the “copper film” means a film formed from copper or a copper alloy, and the copper content in the copper alloy is preferably 95% by mass or more.
  • the chemical mechanical polishing aqueous dispersion according to this embodiment is obtained by directly adding (A) silica particles, (B2) amino acids, and other additives to pure water. Can be prepared by mixing and stirring.
  • the chemical mechanical polishing aqueous dispersion thus obtained may be used as it is, but a chemical mechanical polishing aqueous dispersion containing each component in a high concentration (concentrated) is prepared and desired at the time of use. It may be used after diluting to a concentration of.
  • a plurality of liquids for example, two or three liquids
  • this may be supplied to the chemical mechanical polishing apparatus, or a plurality of liquids may be supplied individually to the chemical mechanical polishing apparatus.
  • a chemical mechanical polishing aqueous dispersion may be formed on a surface plate.
  • the chemical mechanical polishing water is composed of a liquid (I) which is an aqueous dispersion containing water and (A) silica particles, and a liquid (II) containing water and (B2) an amino acid.
  • a kit for preparing a system dispersion can be mentioned.
  • the concentration of each component in the liquids (I) and (II) is particularly as long as the concentration of each component in the chemical mechanical polishing aqueous dispersion finally prepared by mixing these liquids is within the above range. It is not limited. For example, liquids (I) and (II) containing each component at a concentration higher than the concentration of the chemical mechanical polishing aqueous dispersion are prepared, and the liquids (I) and (II) are diluted as necessary at the time of use. Then, these are mixed to prepare a chemical mechanical polishing aqueous dispersion in which the concentration of each component is in the above range.
  • the liquids (I) and (II) when the liquids (I) and (II) are mixed at a weight ratio of 1: 1, the liquids (I) and (I) having a concentration twice the concentration of the chemical mechanical polishing aqueous dispersion. II) may be prepared. Moreover, after preparing liquid (I) and (II) of the density
  • the method and timing of mixing the liquid (I) and the liquid (II) are not particularly limited as long as the chemical mechanical polishing aqueous dispersion is formed at the time of polishing.
  • this may be supplied to a chemical mechanical polishing apparatus, or the liquid (I) and the liquid ( II) may be supplied independently to a chemical mechanical polishing apparatus and mixed on a surface plate.
  • the liquid (I) and the liquid (II) may be independently supplied to the chemical mechanical polishing apparatus and mixed in line in the apparatus, or a mixing tank is provided in the chemical mechanical polishing apparatus, You may mix.
  • a line mixer or the like may be used in order to obtain a more uniform chemical mechanical polishing aqueous dispersion.
  • FIG. 8 shows an object to be treated 200 used in the chemical mechanical polishing method according to this embodiment.
  • the low dielectric constant insulating film 40 is formed by a coating method or a plasma CVD method.
  • the low dielectric constant insulating film 40 include inorganic insulating films and organic insulating films.
  • Parylene film (k 2.7 to 3.0)
  • An insulating film 50 is formed on the low dielectric constant insulating film 40 by using a CVD method or a thermal oxidation method.
  • Examples of the insulating film 50 include a TEOS film.
  • the wiring recess 40 is formed by etching so that the low dielectric constant insulating film 40 and the insulating film 50 are communicated.
  • the barrier metal film 70 is formed so as to cover the surface of the insulating film 50 and the bottom and inner wall surface of the wiring recess 60 using the CVD method.
  • the barrier metal film 70 is preferably Ta or TaN from the viewpoint of excellent adhesion to the copper film and diffusion barrier properties with respect to the copper film.
  • the barrier metal film 70 is not limited to this and is Ti, TiN, Co, Mn, Ru, or the like. May be.
  • the object 200 is obtained by depositing copper on the barrier metal film 70 to form the copper film 80.
  • the second chemical mechanical polishing aqueous system is used in order to remove the copper film 80 deposited on the barrier metal film 70 of the object 200. Chemical mechanical polishing is performed using the dispersion. The copper film 80 is continuously polished by chemical mechanical polishing until the barrier metal film 70 is exposed. Usually, it is necessary to stop polishing after confirming that the barrier metal film 70 is exposed. However, while the second chemical mechanical polishing aqueous dispersion has a very high polishing rate for the copper film, it hardly polishes the barrier metal film. For this reason, as shown in FIG. 9, since the chemical mechanical polishing cannot proceed at the time when the barrier metal film 70 is exposed, the chemical mechanical polishing can be self-stopped.
  • a commercially available chemical mechanical polishing apparatus can be used.
  • a commercially available chemical mechanical polishing apparatus for example, model “EPO-112”, “EPO-222” manufactured by Ebara Manufacturing Co., Ltd .; model “LGP-510”, “LGP-552” manufactured by Lapmaster SFT, Applied Materials Manufactured, model “Mirra” and the like.
  • Preferred polishing conditions in the first step should be appropriately set depending on the chemical mechanical polishing apparatus to be used. For example, when “EPO-112” is used as the chemical mechanical polishing apparatus, the following conditions should be used. Can do. ⁇ Surface plate rotation speed: preferably 30 to 120 rpm, more preferably 40 to 100 rpm Head rotation speed: preferably 30 to 120 rpm, more preferably 40 to 100 rpm -Ratio of surface plate rotation / head rotation: preferably 0.5 to 2, more preferably 0.7 to 1.5 Polishing pressure: preferably 60 to 200 gf / cm 2 , more preferably 100 to 150 gf / cm 2 Chemical chemical polishing aqueous dispersion supply rate; preferably 50 to 400 mL / min, more preferably 100 to 300 mL / min
  • a surface to be polished having excellent flatness can be obtained, and chemical mechanical polishing can be self-stopped without excessively polishing the copper film.
  • the load on the low dielectric constant insulating film 40 can be reduced.
  • the barrier metal film 70 and the copper film 80 are simultaneously subjected to chemical mechanical polishing using the first chemical mechanical polishing aqueous dispersion. As shown in FIG. 10, even after the insulating film 50 is exposed, the chemical mechanical polishing is still continued to remove the insulating film 50. As shown in FIG. 11, the semiconductor device 90 is obtained by stopping the chemical mechanical polishing when the low dielectric constant insulating film 40 is exposed.
  • the commercially available chemical mechanical polishing apparatus shown in the first step described above can be used.
  • Preferred polishing conditions in the second step should be set as appropriate depending on the chemical mechanical polishing apparatus used. For example, when “EPO-112” is used as the chemical mechanical polishing apparatus, the following conditions should be used. Can do. ⁇ Surface plate rotation speed: preferably 30 to 120 rpm, more preferably 40 to 100 rpm Head rotation speed: preferably 30 to 120 rpm, more preferably 40 to 100 rpm -Ratio of surface plate rotation / head rotation: preferably 0.5 to 2, more preferably 0.7 to 1.5 Polishing pressure: preferably 60 to 200 gf / cm 2 , more preferably 100 to 150 gf / cm 2 Chemical chemical polishing aqueous dispersion supply rate; preferably 50 to 300 mL / min, more preferably 100 to 200 mL / min
  • the dispersion aqueous solution containing the silica particles is concentrated under reduced pressure (boiling point 78 ° C.), and the silica concentration is 32.0 mass%, the average particle diameter of silica is 26 nm, and the pH is 9.8. Got.
  • This silica particle dispersion is again passed through the hydrogen-type cation exchange resin layer to remove most of sodium, and then 10% by mass of potassium hydroxide aqueous solution is added, and the silica particle concentration: 28.0% by mass, pH A silica particle dispersion A of 10.0 was obtained.
  • the obtained silica particle dispersion A was titrated with a 0.1N aqueous sodium hydroxide solution in a pH range of 4 to 9, and the silanol group density was calculated from the titration value and the value of the BET specific surface area. / Nm 2 .
  • Silica particles are recovered from the silica particle dispersion A by centrifugation, the silica particles recovered with dilute hydrofluoric acid are dissolved, and sodium is added using ICP-MS (manufactured by PerkinElmer, model number “ELAN DRC PLUS”). And potassium was measured. Further, ammonium ions were measured using ion chromatography (manufactured by DIONEX, model number “ICS-1000”). As a result, the sodium content was 88 ppm, the potassium content was 5500 ppm, and the ammonium ion content was 5 ppm.
  • Silica particle dispersion A was diluted to 0.01% with ion-exchanged water, placed on a collodion membrane having Cu grit having a mesh size of 150 ⁇ m, and dried at room temperature.
  • the particle size was measured at 20000 times using a transmission electron microscope (H-7650, manufactured by Hitachi High-Technologies Corporation). Images were taken, the major axis and minor axis of 50 colloidal silica particles were measured, and the average value was calculated.
  • the ratio (Rmax / Rmin) was calculated from the average value of the major axis (Rmax) and the average value of the minor axis (Rmin), it was 1.1.
  • the average particle size calculated from the specific surface area measured using the BET method was 26 nm.
  • recovered by concentrating and drying the silica particle dispersion A was used.
  • Silica particle dispersions B to D, F, and J were obtained by the same method as described above while controlling the heat aging time, the type and amount of basic compound, and the like.
  • the silica particle dispersion E was produced as follows. First, 35 kg of high-purity colloidal silica (product number: PL-2; solid content concentration 20 mass%, pH 7.4, average secondary particle size 66 nm) manufactured by Fuso Chemical Industry Co., Ltd. and 140 kg of ion-exchanged water were charged into a 40 L autoclave. Hydrothermal treatment was performed at 160 ° C. for 3 hours under a pressure of 0.5 MPa. Next, the dispersion aqueous solution containing the silica particles was concentrated under reduced pressure at a boiling point of 78 ° C.
  • silica particle dispersion E having a silica concentration of 20% by mass, an average secondary particle size of 62 nm, and a pH of 7.5.
  • the obtained silica particle dispersion E was titrated in a pH range of 4 to 9 using a 0.1N aqueous sodium hydroxide solution, and the silanol group density was calculated from the titration value and the value of the BET specific surface area. Pieces / nm 2 .
  • the silica particle dispersion G was produced by a known method using a sol-gel method using tetraethoxysilane as a raw material.
  • Silica particle dispersion H was obtained by a method similar to the method for preparing silica particle dispersion A described above, followed by further hydrothermal treatment (in the preparation of silica particle dispersion, autoclaving was further performed for a long time. The silanol condensation was advanced).
  • Silica particle dispersion I was prepared as follows. First, high purity colloidal silica (product number: PL-2; solid content concentration 20 mass%, pH 7.4, average secondary particle size 66 nm) manufactured by Fuso Chemical Industry Co., Ltd. and dispersed in 140 kg of ion-exchanged water to obtain a silica concentration Produced a silica particle dispersion I having a solid content concentration of 20% by mass, an average secondary particle diameter of 62 nm, and a pH of 7.5.
  • high purity colloidal silica product number: PL-2; solid content concentration 20 mass%, pH 7.4, average secondary particle size 66 nm
  • the obtained silica particle dispersion I was titrated in a pH range of 4 to 9 using a 0.1N aqueous sodium hydroxide solution, and the silanol group density was calculated from the titration value and the value of the BET specific surface area. Pieces / nm 2 .
  • Table 2 summarizes the physical property values of the silica particle dispersions A to J produced.
  • the obtained polyvinylpyrrolidone (K30) was measured by gel permeation chromatography (manufactured by Tosoh Corporation, apparatus model number “HLC-8120”, column model number “TSK-GEL ⁇ -M”, eluent is NaCl aqueous solution / acetonitrile).
  • Mw weight average molecular weight in terms of polyethylene glycol
  • the amount of amino group calculated from the charged amount of monomer was 0 mol / g
  • the amount of cationic functional group was 0 mol / g.
  • polyvinyl pyrrolidone (K60) and polyvinyl pyrrolidone (K90) were produced by appropriately adjusting the amount of the components added, the reaction temperature, and the reaction time.
  • Mw weight average molecular weight
  • the amount of amino group calculated from the charged amount of monomer was 0 mol / g, and the amount of cationic functional group was 0 mol / g.
  • diethyl sulfate having a molar number of 0.35 times that of 1 mol of diethylaminoethyl methacrylate was added and heated under reflux at 50 ° C. for 10 hours under a nitrogen stream to synthesize a vinylpyrrolidone / diethylaminomethyl methacrylate copolymer. .
  • the obtained copolymer was measured by gel permeation chromatography (manufactured by Tosoh Corporation, apparatus model number “HLC-8120”, column model number “TSK-GEL ⁇ -M”, eluent is NaCl aqueous solution / acetonitrile),
  • the weight average molecular weight (Mw) in terms of polyethylene glycol was 100,000.
  • the amount of amino group calculated from the charged amount of monomer was 0.001 mol / g, and the amount of cationic functional group was 0.0006 mol / g.
  • vinylpyrrolidone / diethylaminomethyl methacrylate copolymers having a weight average molecular weight of 400,000 and 1.8 million were synthesized by appropriately adjusting the addition amount of the components, reaction temperature, and reaction time.
  • N-vinylpyrrolidone 70 parts by mass of N-vinylpyrrolidone and 30 parts by mass of DMAPAA (N, N-dimethylaminopropylacrylamide) were added, and a polymerization reaction was performed at 75 ° C. for 5 hours in a nitrogen stream.
  • DMAPAA N, N-dimethylaminopropylacrylamide
  • 0.2 part by mass of 2,2′-azobis (2-methylpropionamidine) dihydrochloride (manufactured by Wako Pure Chemical Industries, Ltd., trade name “V-50”) was added, and the mixture was added at 70 ° C. under nitrogen flow.
  • the mixture was heated under reflux for an hour to obtain an aqueous dispersion containing 11% by mass of vinylpyrrolidone / dimethylaminopropylacrylamide copolymer.
  • the polymerization yield was 99%.
  • the obtained copolymer was measured by gel permeation chromatography (manufactured by Tosoh Corporation, apparatus model number “HLC-8120”, column model number “TSK-GEL ⁇ -M”, eluent is NaCl aqueous solution / acetonitrile),
  • the weight average molecular weight (Mw) in terms of polyethylene glycol was 600,000.
  • the amount of amino group calculated from the charged amount of monomer is 0.0010 mol / g, and the amount of cationic functional group is 0.0006 mol / g.
  • the obtained polyacrylic acid was measured by gel permeation chromatography (manufactured by Tosoh Corporation, apparatus model number “HLC-8120”, column model number “TSK-GEL ⁇ -M”, eluent is NaCl aqueous solution / acetonitrile),
  • the weight average molecular weight (Mw) in terms of polyethylene glycol was 1,000,000.
  • polyacrylic acid having a weight average molecular weight (Mw) of 200,000 was obtained by appropriately adjusting the addition amount of the above components, the reaction temperature, and the reaction time.
  • ion-exchanged water is added so that the total amount of all the components becomes 100 parts by mass, and then filtered through a filter having a pore diameter of 5 ⁇ m to obtain an aqueous dispersion S1 for chemical mechanical polishing having a pH of 10.0. It was.
  • Silica particles are recovered from the chemical mechanical polishing aqueous dispersion S1 by centrifugation, and the silica particles recovered with dilute hydrofluoric acid are dissolved. Then, ICP-MS (manufactured by PerkinElmer, model number “ELAN DRC PLUS”) is used. Used to measure sodium and potassium. Further, ammonium ions were measured using ion chromatography (manufactured by DIONEX, model number “ICS-1000”). As a result, the sodium content was 88 ppm, the potassium content was 5500 ppm, and the ammonium ion content was 5 ppm.
  • silica particles are recovered from the chemical mechanical polishing aqueous dispersion, sodium, potassium and ammonium ions contained in the silica particles can be quantified, and the same result as the silica particle dispersion can be obtained. I understood.
  • the chemical mechanical polishing aqueous dispersions S2 to S41 are the same as those described above except that the types and contents of the silica particle dispersion, organic acid, and other additives are changed as shown in Tables 3 to 8. It was produced in the same manner as the polishing aqueous dispersion S1.
  • “Surfinol 465” and “Surfinol 485” are both 2,4,7,9-tetramethyl-5-decyne-4,7-diol-di, produced by Air Products. It is a trade name of polyoxyethylene ether (acetylenediol type nonionic surfactant), and the number of moles of polyoxyethylene added is different. “Emulgen 104P” is a trade name of polyoxyethylene lauryl ether (an alkyl ether type nonionic surfactant) manufactured by Kao Corporation.
  • polishing conditions and head rotation speed 70 rpm Head load: 200 gf / cm 2 ⁇ Table rotation speed: 70rpm -Supply speed of chemical mechanical polishing aqueous dispersion: 200 mL / min
  • the supply speed of the chemical mechanical polishing aqueous dispersion refers to a value obtained by assigning the total supply amount of all supply liquids per unit time.
  • polishing rate calculation method For the copper film and the tantalum film, the film thickness after the polishing treatment is measured using an electric conduction film thickness measuring instrument (manufactured by KLA Tencor, model “Omnimap RS75”), The polishing rate was calculated from the film thickness reduced by chemical mechanical polishing and the polishing time.
  • the film thickness after polishing treatment is measured using an optical interference film thickness measuring instrument (Nanometrics Japan, model “Nanospec6100”), and reduced by chemical mechanical polishing.
  • the polishing rate was calculated from the obtained film thickness and polishing time.
  • the PETEOS film and the low dielectric constant insulating film were polished in the same manner as in “4.4.1a Measurement of polishing rate”.
  • the substrate was subjected to vapor phase decomposition treatment, and diluted hydrofluoric acid was dropped on the surface to dissolve the surface oxide film, and the dissolved liquid was then added to ICP-MS (manufactured by Perkin Elmer, model number “ELAN DRC”). PLUS ").
  • ultrapure water is dropped on the surface of the substrate to extract the residual metal on the surface of the low dielectric constant insulating film, and then the extracted solution is ICP-MS (manufactured by Yokogawa Analytical Systems, model number “Agilent 7500s”). )).
  • Wafer contamination is preferably 3.0atom / cm 2 or less, and more preferably 2.5atom / cm 2 or less.
  • Patterned wafer A silicon nitride film having a thickness of 1000 ⁇ is deposited on a silicon substrate, a low dielectric constant insulating film (Black Diamond film) is further stacked thereon in a thickness of 4500 ⁇ , and a PETEOS film is sequentially stacked in a thickness of 500 ⁇ .
  • An 854 "mask pattern was processed, and a test substrate on which a 250 angstrom tantalum film, a 1000 angstrom copper seed film, and a 10,000 angstrom copper plating film were sequentially laminated was used.
  • Polishing conditions for the first polishing treatment step / Chemical mechanical polishing aqueous dispersion for the first polishing treatment step includes “CMS7401”, “CMS7452” (both manufactured by JSR Corporation), ion exchange A mixture of water and a 4% by mass aqueous ammonium persulfate solution at a mass ratio of 1: 1: 2: 4 was used.
  • the supply speed of the chemical mechanical polishing aqueous dispersion refers to a value obtained by assigning the total supply amount of all supply liquids per unit time.
  • Polishing time 2.75 minutes
  • polishing conditions in the second polishing treatment step As the aqueous dispersions for the second polishing treatment step, chemical mechanical polishing aqueous dispersions S1 to S12 were used. -Head rotation speed: 70 rpm Head load: 200 gf / cm 2 ⁇ Table rotation speed: 70rpm -Supply speed of chemical mechanical polishing aqueous dispersion: 200 mL / min In this case, the supply speed of the chemical mechanical polishing aqueous dispersion refers to a value obtained by assigning the total supply amount of all supply liquids per unit time. Polishing time: The time at which polishing was further performed for 30 seconds from the time when the PETEOS film was removed from the surface to be polished was defined as the polishing end point, and Table 3 to Table 4 described as “patterned substrate polishing time”.
  • a copper wiring width (line, L) is used using a high-resolution profiler (KLA Tencor, model “HRP240ETCH”).
  • KLA Tencor model “HRP240ETCH”.
  • Insulating film width space, S was measured for dishing amount (nm) in copper wiring portions of 100 ⁇ m / 100 ⁇ m, respectively.
  • the dishing amount was displayed as minus when the upper surface of the copper wiring was convex above the reference surface (upper surface of the insulating film).
  • the dishing amount is preferably -5 to 30 nm, more preferably -2 to 20 nm.
  • a portion where the fine wiring length is 1000 ⁇ m in a pattern in which the copper wiring width (line, L) / insulating film width (space, S) is 9 ⁇ m / 1 ⁇ m, respectively.
  • the amount of erosion was measured. Note that the erosion amount is indicated by minus when the upper surface of the copper wiring is convex above the reference surface (upper surface of the insulating film).
  • the amount of erosion is preferably ⁇ 5 to 30 nm, and more preferably ⁇ 2 to 20 nm.
  • the surface to be polished of the patterned wafer after the second polishing process step was evaluated by using a stylus type step gauge (model “HRP240”, manufactured by KLA Tencor) for the fan of the 100 ⁇ m wiring pattern portion.
  • the evaluation of the fang was performed on the gap between the insulating film or barrier metal film formed at the interface between the insulating film or barrier metal film on the wafer and the wiring portion. The smaller the fang, the better the planarization performance of the wiring part.
  • the fang is preferably 0 to 30 nm, and more preferably 0 to 25 nm.
  • the surface to be polished of the patterned wafer after the second polishing process step is subjected to the number of polishing scratches (scratches) using a defect inspection apparatus (model “2351” manufactured by KLA Tencor). It was measured. In Tables 3 to 4, the number of scratches per wafer is indicated by the unit “piece / wafer”. The number of scratches is preferably less than 100 / wafer.
  • S7 used in Comparative Example 1 corresponds to a composition in which components corresponding to organic acids are deleted from S3 used in Example 3.
  • the storage stability of the silica particles was good.
  • the polishing rate for the copper film and the barrier metal film was clearly higher in Example 3 than in Comparative Example 1.
  • scratches on the copper film were significantly reduced in Example 3 than in Comparative Example 1. From the above results, the superiority of using an organic acid was shown.
  • S11 used in Comparative Example 5 contains the silica particle dispersion H having a silanol group density of 0.8 / nm 2 , the storage stability of the silica particles was not excellent.
  • the polishing test of the polishing rate measuring substrate occurrence of wafer contamination was observed.
  • the polishing test of the patterned wafer many scratches were observed due to the agglomerated silica.
  • the polishing rate for the low dielectric constant insulating film is reduced, and the high polishing rate and the high polishing rate for the copper film, the tantalum film, and the PETEOS film are reduced. It was found that the flattening characteristics can be made compatible.
  • high-quality chemical mechanical polishing can be realized without causing defects in the metal film and the low dielectric constant insulating film, and metal contamination of the wafer can be achieved. It was found that can be reduced.
  • Polishing Rate Measurement Substrate Silicon substrate with an 8-inch thermal oxide film on which a copper film having a thickness of 15,000 angstroms is laminated. A silicon substrate with an 8-inch thermal oxide film on which a tantalum film having a thickness of 2,000 angstroms is laminated.
  • polishing conditions and head rotation speed 70 rpm Head load: 200 gf / cm 2 ⁇ Table rotation speed: 70rpm -Supply speed of chemical mechanical polishing aqueous dispersion: 200 mL / min
  • the supply speed of the chemical mechanical polishing aqueous dispersion refers to a value obtained by assigning the total supply amount of all supply liquids per unit time.
  • polishing rate calculation method For the copper film and the tantalum film, the film thickness after the polishing treatment was measured using an electroconductive film thickness measuring instrument (model “Omnimap RS75”, manufactured by KLA Tencor). The polishing rate was calculated from the film thickness decreased by mechanical polishing and the polishing time.
  • Wafer Contamination The copper film was polished in the same manner as in “4.5.1a Polishing Rate Measurement”. Subsequently, ultrapure water was dropped on the sample surface to extract the residual metal on the copper film surface, and the extract was quantified by ICP-MS (manufactured by Yokogawa Analytical Systems, model number “Agilent 7500s”). Wafer contamination, is preferably 3.0atom / cm 2 or less, and more preferably 2.5atom / cm 2 or less.
  • a chemical polishing machine (Ebara Corporation, model “EPO112”) is equipped with a porous polyurethane polishing pad (Nitta Haas, product number “IC1000”). While supplying any one of the mechanical polishing aqueous dispersions S13 to S41, with respect to the wafer with the following pattern, the point when the tantalum film was detected on the surface to be polished was determined as the polishing end point.
  • the polishing treatment was performed in the same manner as the polishing conditions in “5.1a Measurement of polishing rate”, and the flatness and the presence or absence of defects were evaluated by the following methods. The results are also shown in Tables 5 to 8.
  • Patterned wafer A silicon nitride film having a thickness of 1000 ⁇ is deposited on a silicon substrate, a low dielectric constant insulating film (Black Diamond film) is further stacked thereon in a thickness of 4500 ⁇ , and a PETEOS film is sequentially stacked in a thickness of 500 ⁇ .
  • An 854 "mask pattern was processed, and a test substrate on which a 250 angstrom tantalum film, a 1000 angstrom copper seed film, and a 10,000 angstrom copper plating film were sequentially laminated was used.
  • the amount of erosion is preferably ⁇ 5 to 30 nm, and more preferably ⁇ 2 to 20 nm.
  • the evaluation item “Cu residue” in the table represents the Cu residue on the pattern, and “ ⁇ ” represents that the Cu residue is completely eliminated and is the most preferable state. “ ⁇ ” represents a slightly preferable state in which Cu residue is present in some patterns. “X” indicates that Cu residue is generated in all patterns and the polishing performance is poor.
  • S36 used in Comparative Example 13 contains a silica particle dispersion G having a silanol group density of 4.2 particles / nm 2 , but the silica particles are dispersed by balancing the type and concentration of additives. It was possible to stabilize. However, in the polishing test of the substrate for measuring the polishing rate, the polishing rate for the copper film is not sufficient as 7,500 angstrom / min, while the polishing rate for the tantalum film becomes as large as 30 angstrom / min and the polishing selectivity is lowered. Was recognized. In the polishing test of the patterned wafer, dishing, erosion, corrosion, and copper residue were observed, and a good polished surface could not be obtained.
  • S37 used in Comparative Example 14 contains a silica particle dispersion G having a silanol group density of 4.2 particles / nm 2 , but the silica particles are dispersed by balancing the type and concentration of additives. It was possible to stabilize. However, in the polishing test of the substrate for polishing rate measurement, the polishing rate for the copper film was not sufficient at 6,000 angstroms / minute. In the polishing test of the patterned wafer, occurrence of copper residue was observed, and a good polished surface could not be obtained.
  • S40 used in Comparative Example 17 contains a silica particle dispersion I having a silanol group density of 3.8 particles / nm 2 , but by balancing the types and concentrations of additives, the silica particles It was possible to stabilize. However, in the polishing test of the substrate for measuring the polishing rate, the polishing rate for the copper film is reduced to 280 angstrom / min, while the polishing rate for the tantalum film is remarkably increased to 820 angstrom / min, and the polishing selectivity is deteriorated. It was.

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Abstract

L'invention porte sur une dispersion aqueuse pour polissage mécano-chimique, qui contient (A) des particules de silice et (B1) un acide organique. Les particules de silice (A) présentent une propriété chimique telle que leur densité de groupe silanol, calculée sur la base de la surface spécifique déterminée à l'aide d'un procédé BET et la quantité de groupes silanol déterminée par titrage, est de 1,0 à 3,0 groupes/nm2.
PCT/JP2009/051582 2008-02-18 2009-01-30 Dispersion aqueuse pour polissage mécano-chimique et procédé de polissage mécano-chimique WO2009104465A1 (fr)

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JP2017019978A (ja) * 2015-07-15 2017-01-26 株式会社フジミインコーポレーテッド 研磨用組成物、磁気ディスク基板製造方法および磁気ディスク基板
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WO2016063505A1 (fr) * 2014-10-22 2016-04-28 株式会社フジミインコーポレーテッド Composition pour polissage
JP2016084371A (ja) * 2014-10-22 2016-05-19 株式会社フジミインコーポレーテッド 研磨用組成物
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JP2020132478A (ja) * 2019-02-21 2020-08-31 三菱ケミカル株式会社 シリカ粒子の製造方法、シリカゾルの製造方法及び研磨方法
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