WO2023080014A1 - Polishing agent, additive liquid and polishing method - Google Patents

Polishing agent, additive liquid and polishing method Download PDF

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Publication number
WO2023080014A1
WO2023080014A1 PCT/JP2022/039682 JP2022039682W WO2023080014A1 WO 2023080014 A1 WO2023080014 A1 WO 2023080014A1 JP 2022039682 W JP2022039682 W JP 2022039682W WO 2023080014 A1 WO2023080014 A1 WO 2023080014A1
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Prior art keywords
polishing
abrasive
metal salt
metal
water
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PCT/JP2022/039682
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French (fr)
Japanese (ja)
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友洋 渋谷
有造 岡村
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Ａｇｃ株式会社
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Publication of WO2023080014A1 publication Critical patent/WO2023080014A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • 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
    • 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting

Definitions

  • the present invention relates to an abrasive, an additive liquid, and a polishing method.
  • CMP chemical mechanical polishing
  • STI shallow trench isolation
  • FIGS. 1A and 1B An example of STI will be described with reference to FIGS. 1A and 1B.
  • FIGS. 1A and 1B first, as shown in FIG. 1A, after masking the device region of the silicon substrate 1 with a silicon nitride film 2 or the like, trenches 3 are formed in the silicon substrate 1 and filled in.
  • An insulating film such as a silicon oxide film 4 is deposited. Next, by CMP, the silicon oxide film 4 on the silicon nitride film 2, which is a convex portion, is polished and removed while leaving the silicon oxide film 4 in the trench 3, which is a concave portion. An element isolation structure is obtained in which the silicon oxide film 4 is embedded in the silicon oxide film 3 .
  • Patent Document 1 discloses a polishing agent containing a specific water-soluble polymer, cerium oxide particles, and water and having a pH of 4-9. According to the polishing agent of Patent Document 1, the polishing rate for a silicon nitride film can be kept low while maintaining a high polishing rate for a silicon oxide film. In the examples of FIGS. 1A and 1B, the silicon nitride film 2 serves as a polishing stopper film, so that a good flat surface can be obtained.
  • FIGS. 2A-2C Another example of STI is described with reference to FIGS. 2A-2C.
  • a laminated body in which a silicon nitride film 13 and a silicon oxide film 14 are laminated on an element region of a silicon substrate 10 is to be polished.
  • the silicon substrate 10 is divided into crystalline silicon 11 and amorphous silicon 12 for the sake of convenience, but the configuration is not limited to this. Also, the boundary between the crystalline silicon 11 and the amorphous silicon 12 may not be clear.
  • a silicon nitride film can be polished at a high speed in order to uniformly polish a silicon oxide film and a silicon nitride film while maintaining a sufficiently high polishing rate, and also from the viewpoint of polishing a silicon nitride film alone. Abrasives were required.
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polishing agent containing cerium oxide and a metal salt capable of polishing a silicon nitride film at high speed.
  • the abrasive according to the present invention contains abrasive grains (A), a sparingly water-soluble metal salt (B), and water.
  • the metal salt (B) contains at least one metal salt selected from the group consisting of metal carbonate, metal sulfate, metal phosphate, metal acetate and metal oxalate. You can
  • the metal carbonate may contain at least one metal salt selected from the group consisting of barium carbonate and strontium carbonate.
  • the metal sulfate may contain at least one metal salt selected from the group consisting of barium sulfate and strontium sulfate.
  • the content of the metal salt (B) in the abrasive may be 0.1% by mass or more and 5% by mass or less with respect to the total mass of the abrasive.
  • the content of the metal salt (B) may be 0.1 to 20 in mass ratio (B/A) to the abrasive grains (A).
  • the abrasive grains (A) may contain at least one selected from the group consisting of cerium oxide and colloidal silica.
  • the additive liquid according to the present invention contains a sparingly water-soluble metal salt (B), a dispersant (C), and water.
  • the polishing method according to the present invention is a polishing method in which a surface to be polished and a polishing pad are brought into contact with each other while a polishing agent is supplied, and polishing is performed by relative movement of the two, and the polishing agent according to the present invention is used as the polishing agent. Then, the surface to be polished containing silicon oxide and/or silicon nitride of the semiconductor substrate is polished.
  • the present invention provides a polishing agent containing cerium oxide capable of polishing a silicon nitride film at high speed.
  • the term "surface to be polished” refers to a surface to be polished of an object to be polished, and means, for example, a surface.
  • the "surface to be polished” includes an intermediate stage surface appearing on the semiconductor substrate in the process of manufacturing a semiconductor device.
  • silicon oxide is mainly silicon dioxide, but is not limited thereto and may contain silicon oxides other than silicon dioxide.
  • "-" indicating a numerical range includes the numerical values described before and after it as a lower limit and an upper limit. For clarity of explanation, the following description and drawings have been simplified where appropriate. Also, for the sake of explanation, the scale of each member in the drawings may differ greatly.
  • the abrasive according to the present invention (hereinafter also referred to as the present abrasive) comprises abrasive grains (A), a sparingly water-soluble metal salt (B) (simply referred to as metal salt (B)), and water. It may contain other components as long as the effect of the present invention is exhibited.
  • This abrasive contains abrasive grains (A).
  • Abrasive grains can be appropriately selected and used from those used as abrasive grains for CMP.
  • the abrasive grains are preferably metal oxide particles from the viewpoint of excellent polishing rate for silicon nitride and silicon oxide.
  • Metal oxides include metal oxides selected from the group consisting of cerium oxide (ceria), alumina, silica, titania, and zirconia. Among them, cerium oxide or colloidal silica is preferable from the viewpoint of excellent polishing rate of silicon nitride or silicon oxide.
  • the abrasive grains (A) can be used singly or in combination of two or more.
  • Cerium oxide particles for abrasive grains can be appropriately selected from known ones and used. Examples thereof include cerium oxide particles produced by the methods described in JP-A-11-12561, JP-A-2001-35818, and JP-A-2010-505735. Specifically, cerium oxide particles obtained by adding an alkali to an aqueous solution of cerium(IV) ammonium nitrate to prepare a cerium hydroxide gel, filtering, washing and calcining the gel; , cerium oxide particles obtained by pulverization and classification; and cerium oxide particles obtained by chemically oxidizing cerium (III) salt in liquid.
  • the average particle size of the abrasive grains (A) is preferably 0.01-0.5 ⁇ m, more preferably 0.03-0.3 ⁇ m. If the average particle size is 0.5 ⁇ m or less, the occurrence of polishing flaws such as scratches on the surface to be polished is suppressed. Further, when the average particle diameter is 0.01 ⁇ m or more, coarse agglomeration of the abrasive grains (A) is suppressed, the storage stability of the abrasive is excellent, and the polishing rate is also excellent. Since the abrasive grains (A) exist as aggregated particles (secondary particles) in which the primary particles are aggregated in the liquid, the preferred particle size of the abrasive grains (A) is represented by the average secondary particle size.
  • the average particle size indicated in the above numerical range is usually the average secondary particle size.
  • the average secondary particle size is measured using a particle size distribution meter such as a laser diffraction/scattering type using a dispersion liquid dispersed in a dispersion medium such as pure water.
  • the content (concentration) of the abrasive grains (A) is preferably 0.05 to 2.0% by mass, more preferably 0.1 to 0.5% by mass, relative to the total abrasive. If the content of abrasive grains is at least the above lower limit, an excellent polishing rate can be obtained. On the other hand, if the content of the abrasive grains is equal to or less than the above upper limit, the increase in viscosity of the present polishing agent is suppressed, and the handleability is excellent.
  • ⁇ Metal salt (B)> This abrasive is characterized by containing a metal salt (B) that is sparingly soluble in water.
  • the inventor presumes as follows about the effect of increasing the polishing rate of the silicon nitride film by containing the metal salt (B).
  • 5A and 5B are schematic cross-sectional views for explaining the action of the metal salt (B).
  • This abrasive contains abrasive grains (A) 31 and metal salt (B) 32 dispersed in water, which is a solvent. In the example of FIG.
  • the surface of the silicon nitride film 13, which is the surface to be polished, is hydrated by contact with water, and it is presumed that part of the silicon nitride is changed to silicon oxide 13a (FIG. 5B).
  • the presence of the metal salt (B) 32 near the surface of the silicon nitride film 13 accelerates the hydration.
  • the exposed outermost surface of the silicon nitride film 13 is sequentially changed into silicon oxide having a high polishing speed due to the action of the metal salt (B), thereby increasing the polishing speed of the abrasive grains (A). be done.
  • the metal salt (B) and the sparingly water-soluble metal salt can be appropriately selected and used in the abrasive of the present invention.
  • "sparingly soluble in water” means that the solubility at 25°C is less than 1 g, preferably 0.5 g or less, more preferably 0.1 g or less.
  • the sparingly water-soluble metal salt (B) metal carbonate, metal sulfate, metal phosphate, metal oxalate, metal acetate, and the like are mentioned from the viewpoint of further improving the polishing rate of the silicon nitride film.
  • the metal constituting the metal salt (B) is preferably an alkaline earth metal or a lanthanide from the viewpoint of further improving the polishing rate of the silicon nitride film. Strontium is more preferred.
  • sparingly water-soluble metal salt (B) examples include barium carbonate, strontium carbonate, lanthanum carbonate, cerium carbonate, barium sulfate, strontium sulfate, lanthanum sulfate, cerium sulfate, barium phosphate, strontium phosphate, and phosphoric acid.
  • metal salt (B) can be used individually by 1 type or in combination of 2 or more types.
  • the average particle size of the metal salt (B) is not particularly limited, but may be, for example, 5 nm to 3 ⁇ m, preferably 10 nm to 2 ⁇ m.
  • the average particle size of the metal salt (B) is equal to or less than the above upper limit, the occurrence of polishing flaws such as scratches on the surface to be polished is suppressed.
  • the content is at least the above lower limit, coarse agglomeration of the metal salt (B) is suppressed, and the storage stability of the polishing agent is excellent, and the polishing rate is also excellent.
  • the method for measuring the average particle size of the metal salt (B) is the same as that for the abrasive grains (A).
  • the content of the metal salt (B) is preferably 0.1% by mass or more and 5% by mass or less with respect to the total mass of the polishing agent, from the viewpoint of further improving the polishing rate of the silicon nitride film. Further, the content of the metal salt (B) is preferably 0.1 to 20 in mass ratio (B/A) to the abrasive grains (A) from the viewpoint of further improving the polishing rate of the silicon nitride film. .
  • the abrasive of the present invention contains water as a medium for dispersing the abrasive grains (A) and the metal salt (B).
  • the type of water is not particularly limited, it is preferable to use pure water, ultrapure water, ion-exchanged water, etc. in consideration of effects on water-soluble polymers, etc., prevention of contamination by impurities, effects on pH, etc. .
  • the polishing agent may further contain other components within the range in which the effects of the present invention are exhibited.
  • Other ingredients include dispersants, pH modifiers, lubricants, polymers, and the like.
  • a dispersant (C) is optionally used to improve the dispersibility and dispersion stability of the abrasive grains (A) and/or the metal salt (B).
  • the dispersing agent it can be used by appropriately selecting from known ones used for abrasive applications. Examples include ionic, nonionic, and amphoteric polymer compounds, and one or more of these can be used.
  • a water-soluble organic polymer or an anionic surfactant is preferred.
  • a polymer having a carboxyl group or a carboxylate ammonium salt or the like is preferable, and polyacrylic acid or polyacrylic acid salt is particularly preferable.
  • the content ratio is the total of the abrasive grains (A) and the metal salt (B) from the viewpoint of the dispersibility and dispersion stability of the abrasive grains (A) and/or the metal salt (B). It is preferably 0.0001 to 10 parts by mass, more preferably 0.0001 to 5 parts by mass, even more preferably 0.001 to 1 part by mass, based on 100 parts by mass.
  • a pH adjuster may be used to adjust the pH of the abrasive.
  • As the pH adjuster it is possible to appropriately select and use water-soluble inorganic acids, organic acids, basic compounds, amphoteric compounds such as amino acids, and salts thereof.
  • inorganic acids include nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, etc., and their ammonium salts, sodium salts, potassium salts, etc. may be used.
  • examples of organic acids include carboxylic acids, organic sulfonic acids, organic phosphoric acids and the like, and their ammonium salts, sodium salts, potassium salts and the like may be used.
  • carboxylic acids include acetic acid, propionic acid, lactic acid, tartaric acid, oxalic acid, and maleic acid.
  • organic sulfonic acids include benzenesulfonic acid and tosylic acid.
  • organic phosphoric acids include methylphosphonic acid and dimethylphosphinic acid.
  • Basic compounds include ammonia, potassium hydroxide, tetramethylammonium hydroxide, ethylenediamine, and the like.
  • Amphoteric compounds include glycine, alanine, phenylalanine, and the like.
  • the pH of the polishing agent is preferably 3 or more and 12 or less. When the pH of the polishing agent is within this range, the effect of polishing the silicon nitride film at high speed while polishing the silicon oxide film at high speed is sufficiently obtained.
  • the pH of the polishing agent is more preferably 4 or more and 11 or less, and particularly preferably 4.5 or more and 10 or less, from the viewpoint of further improving the polishing rate of the silicon nitride film.
  • the content of the pH adjuster may be appropriately adjusted so as to achieve the above pH. As an example, it can be 0.005 to 2.0% by mass, preferably 0.01 to 1.5% by mass, more preferably 0.01 to 0.3% by mass, based on the entire polishing agent.
  • the lubricant is used as necessary to improve the lubricity of the polishing agent and improve the in-plane uniformity of the polishing rate.
  • examples of lubricants include water-soluble polymers such as polyethylene glycol and polyglycerin.
  • the absolute value of the .zeta.-potential of the abrasive is preferably 30 mV or more. When the .zeta.-potential of the polishing agent is within this range, the effect of polishing the silicon nitride film at high speed while maintaining the dispersion stability is sufficiently obtained.
  • the ⁇ potential of the abrasive is more preferably 40 mV or more in absolute value, and particularly preferably 50 mV or more in absolute value. Note that the .zeta.-potential can be adjusted by selecting the above dispersant or the like.
  • the preparation method of this polishing agent is selected from among the methods of uniformly dispersing or dissolving the abrasive grains (A), the sparingly water-soluble metal salt (B), and optional components in water, which is a medium. It can be selected as appropriate.
  • a polishing liquid containing a sparingly water-soluble metal salt (B), a dispersant (C), and water, and a slurry containing abrasive grains (A) are separately prepared, and these are mixed to perform the main polishing. Preparation of agents is preferred.
  • the polishing agent may be prepared just before use by carrying out the above-described mixing in a polishing apparatus.
  • the abrasive of the present invention comprises a dispersion of abrasive grains (hereinafter also referred to as dispersion ⁇ ), a sparingly water-soluble metal salt (B), a dispersant (C), and a water-containing dispersion (hereinafter also referred to as dispersion ⁇ ) may be separately prepared and mixed at the time of use.
  • This dispersion ⁇ is the additive liquid for polishing described below.
  • the (polishing) additive liquid of the present invention is an additive liquid for preparing a polishing agent by mixing with a dispersion liquid of abrasive grains (dispersion liquid ⁇ described above), and comprises a sparingly water-soluble metal salt (B) , dispersant (C) and water.
  • a dispersion liquid of abrasive grains dispersion liquid ⁇ described above
  • a sparingly water-soluble metal salt (B) , dispersant (C) and water By using this additive liquid for polishing in the preparation of a polishing agent, the convenience of storing and transporting the polishing agent can be improved.
  • the sparingly water-soluble metal salt (B), dispersant (C), and water are the same as those described for each component contained in the polishing agent and the pH of the solution. is.
  • the content (concentration) of the sparingly water-soluble metal salt (B) is not particularly limited. From the viewpoint of ease of application, it is preferably 0.1% by mass or more and 10% by mass or less with respect to the total amount of the additive liquid.
  • the content ratio (concentration) of the dispersant (C) is not particularly limited, but from the viewpoint of ease of handling of the additive liquid and ease of mixing with the dispersion liquid of abrasive grains. Therefore, it is preferably 0.1% by mass or more and 10% by mass or less with respect to the total amount of the additive liquid.
  • the content ratio (concentration) of the abrasive grains in the liquid is determined from the viewpoint of dispersibility of the abrasive grains and ease of handling of the dispersion liquid. 0.01 mass % or more and 40 mass % or less are preferable. 0.01% by mass or more and 20% by mass or less is more preferable, and 0.01% by mass or more and 10% by mass or less is particularly preferable.
  • the above-described polishing agent that polishes both the silicon oxide film and the silicon nitride at a high speed while maintaining sufficiently high flatness of the silicon oxide film is obtained.
  • the polishing additive liquid may be added to the abrasive grain dispersion liquid and mixed, or the abrasive grain dispersion liquid may be added to the polishing additive liquid. You may add and mix.
  • the mixing ratio of the polishing additive liquid and the dispersion liquid of abrasive grains is not particularly limited. (Concentration) is preferably 0.1% by mass or more and 5% by mass or less and 0.0002% by mass or more and 2% by mass or less with respect to the total mass of the abrasive. From the standpoint of ease of mixing the additive liquid for polishing and the dispersion liquid of abrasive grains, it is preferable to mix the additive liquid for polishing and the dispersion liquid of abrasive grains at a mass ratio of 130:1 to 1:130.
  • the abrasive of the present invention does not necessarily have to be supplied to the polishing site as a mixture of all constituent polishing components in advance.
  • the polishing components When supplied to the polishing station, the polishing components may be mixed into the composition of the abrasive.
  • the abrasive of the present invention is prepared separately as two liquids, a dispersion of abrasive grains (dispersion ⁇ ) and the above polishing additive liquid (dispersion ⁇ ). May be mixed.
  • the sparingly water-soluble metal salt (B) and the dispersing agent ( The concentration of C) and water may be concentrated to, for example, about 10 times the concentration of the abrasive when used, and after mixing, diluted with water to a predetermined concentration before use.
  • polishing method using the present abrasive there is a method in which the surface to be polished of the object to be polished and the polishing pad are brought into contact while supplying the present polishing agent, and polishing is performed by relative movement of the two.
  • the surface to be polished includes, for example, a blanket wafer in which a silicon nitride film and a silicon oxide film are laminated on the surface of a semiconductor substrate, a pattern wafer in which these film types are arranged in a pattern, and the like. mentioned. According to this polishing method, for example, as shown in FIG.
  • a laminate obtained by laminating a silicon nitride film 13 and a silicon oxide film 14 on an element region of a silicon substrate 10 is to be polished.
  • a so-called PE-TEOS film which is formed by plasma CVD using tetraethoxysilane (TEOS) as a raw material, can be used as the silicon oxide film on the STI substrate.
  • TEOS tetraethoxysilane
  • a silicon oxide film a so-called HDP film formed by a high-density plasma CVD method can be mentioned.
  • a HARP film or FCVD film formed by other CVD methods, or an SOD film formed by spin coating can also be used.
  • Examples of the silicon nitride film include those formed by low-pressure CVD, plasma CVD, and ALD using silane or dichlorosilane and ammonia as raw materials.
  • FIG. 4 is a schematic diagram showing an example of a polishing apparatus.
  • the polishing apparatus 20 shown in the example of FIG. 4 includes a polishing head 22 holding a semiconductor substrate 21 such as an STI substrate, a polishing surface plate 23, a polishing pad 24 attached to the surface of the polishing surface plate 23, and a polishing surface. and an abrasive supply pipe 26 for supplying an abrasive 25 to the pad 24 .
  • the surface to be polished of the semiconductor substrate 21 held by the polishing head 22 is brought into contact with the polishing pad 24 while the polishing agent 25 is being supplied from the polishing agent supply pipe 26, and the polishing head 22 and the polishing platen 23 are relatively rotated. It is configured to be moved and polished.
  • the polishing head 22 may perform linear motion as well as rotational motion.
  • the polishing surface plate 23 and the polishing pad 24 may be of the same size as or smaller than the semiconductor substrate 21 . In that case, it is preferable to polish the entire surface of the semiconductor substrate 21 to be polished by relatively moving the polishing head 22 and the polishing platen 23 .
  • the polishing platen 23 and the polishing pad 24 may not be rotating, and may be belt-type and move in one direction.
  • the polishing conditions of the polishing apparatus 20 are not particularly limited, but by applying a load to the polishing head 22 and pressing it against the polishing pad 24, the polishing pressure can be increased and the polishing speed can be improved.
  • the polishing pressure is preferably about 0.5 to 50 kPa, and more preferably about 3 to 40 kPa from the viewpoint of uniformity and flatness of the polishing rate in the surface to be polished of the semiconductor substrate 21, and prevention of polishing defects such as scratches.
  • the number of revolutions of the polishing surface plate 23 and the polishing head 22 is preferably about 50 to 500 rpm. Further, the supply amount of the polishing agent 25 is appropriately adjusted depending on the composition of the polishing agent, the above polishing conditions, and the like.
  • the polishing pad 24 one made of non-woven fabric, foamed polyurethane, porous resin, non-porous resin, or the like can be used.
  • the surface of the polishing pad 24 is grooved in a lattice, concentric, spiral, or the like. may be applied. If necessary, a pad conditioner may be brought into contact with the surface of the polishing pad 24 to condition the surface of the polishing pad 24 while polishing.
  • Polishing characteristics were evaluated by performing the following polishing using a fully automatic CMP polishing apparatus (manufactured by Applied Materials, apparatus name: Mirra). A two-layer polyurethane pad (with a Shore D value of 65) was used as the polishing pad, and a CVD diamond pad conditioner (manufactured by Kinik, trade name: Pyradia 179B) was used for conditioning the polishing pad.
  • the polishing conditions were a polishing pressure of 21 kPa, a polishing platen rotation speed of 77 rpm, and a polishing head rotation speed of 73 rpm. Also, the supply rate of the abrasive was set to 200 ml/min.
  • polishing speed measuring device A film thickness meter UV-1280SE manufactured by KLA-Tencor was used to measure the film thickness of each film, and the polishing speed (polishing rate) was calculated from changes in polishing time and film thickness.
  • Example 1 Preparation of abrasive
  • About 30 g of cerium oxide having an average particle size of 100 nm was placed in a container containing 270 mL of pure water, and irradiated with an ultrasonic homogenizer for 5 minutes to be pulverized and dispersed.
  • the injection collision treatment was repeated five times, followed by pulverization and dispersion treatment to obtain slurry in which cerium oxide was dispersed.
  • US-600TCVP Appatus name
  • NIHONSEIKI KAISHA was used as an ultrasonic homogenizer
  • Starburst Mini manufactured by Sugino Machine was used as a wet jet mill.
  • the resulting 10% cerium oxide slurry was diluted to form the Example 1 abrasive.
  • Example 2 Preparation of abrasive
  • barium carbonate manufactured by Kanto Kagaku Co., Ltd.
  • a dispersant ammonium polyacrylate
  • the injection collision treatment was repeated five times, followed by pulverization and dispersion treatment to obtain a slurry in which barium carbonate was dispersed.
  • the resulting 10% barium carbonate slurry was diluted to form the Example 2 abrasive.
  • the metal salts (B) of Examples 3 to 12 were also subjected to the same dispersion treatment.
  • Example 3 Preparation of abrasive
  • a slurry was prepared by adding 3.0 g of lanthanum carbonate octahydrate (manufactured by Kanto Kagaku Co., Ltd.) to the polishing agent of Example 1.
  • the resulting cerium oxide slurry was diluted to form the polishing agent of Example 3.
  • Example 4 Preparation of abrasive
  • a slurry was prepared by adding cerium carbonate octahydrate (manufactured by Kanto Kagaku Co., Ltd.) to the abrasive of Example 1 so that the amount of cerium carbonate was 3.0 g.
  • the obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 4.
  • Example 5 Preparation of abrasive
  • a slurry was prepared by adding 3.0 g of barium carbonate (manufactured by Kanto Kagaku Co., Ltd.) to the polishing agent of Example 1.
  • the obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 5.
  • Example 6 Preparation of abrasive
  • a slurry was prepared by adding 1.5 g of barium carbonate (manufactured by Kanto Kagaku Co., Ltd.) to the abrasive of Example 1.
  • the obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 6.
  • Example 7 Preparation of abrasive
  • a slurry was prepared by adding 0.3 g of barium carbonate (manufactured by Kanto Kagaku Co., Ltd.) to the polishing agent of Example 1.
  • the obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 7.
  • Example 8 Preparation of abrasive
  • a slurry was prepared by adding 3.0 g of barium carbonate BW-KH30 (manufactured by Sakai Chemical Industry Co., Ltd.) to the abrasive of Example 1.
  • the resulting cerium oxide slurry was diluted to obtain the polishing agent of Example 8.
  • Example 9 Preparation of abrasive
  • a slurry was prepared by adding 3.0 g of strontium carbonate SW-K40 (manufactured by Sakai Chemical Industry Co., Ltd.) to the abrasive of Example 1.
  • the obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 9.
  • Example 10 Preparation of abrasive
  • a slurry was prepared by adding an appropriate amount of an aqueous nitric acid solution to the polishing agent of Example 8 and adjusting the pH to 4.5.
  • the resulting cerium oxide slurry was diluted to form the polishing agent of Example 10.
  • Example 11 Preparation of abrasive
  • a slurry was prepared by adjusting the pH to 10 by adding an appropriate amount of an aqueous potassium hydroxide solution to the polishing agent of Example 8.
  • the resulting cerium oxide slurry was diluted to form the polishing agent of Example 11.
  • Example 12 Preparation of abrasive
  • a slurry was prepared by adding 3.0 g of strontium sulfate (manufactured by Kanto Kagaku Co., Ltd.) to the polishing agent of Example 1.
  • the obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 12.
  • Example 13 Preparation of abrasive
  • a slurry was prepared by adding 3.0 g of strontium oxalate (manufactured by Kanto Kagaku Co., Ltd.) to the abrasive of Example 1.
  • the obtained cerium oxide slurry was used as the polishing agent of Example 13.
  • Example 14 Preparation of abrasive
  • a slurry was prepared by adding 3.0 g of barium oxalate (manufactured by Kanto Kagaku Co., Ltd.) to the polishing agent of Example 1.
  • the resulting cerium oxide slurry was used as the polishing agent of Example 14.
  • Example 15 Preparation of abrasive
  • a slurry was prepared by adding 3.0 g of barium phosphate (manufactured by Kanto Kagaku Co., Ltd.) to the abrasive of Example 1.
  • the resulting cerium oxide slurry was used as the polishing agent of Example 15.
  • All of the metal salts (B) of Examples 2 to 12 and Examples 13 to 15 are sparingly water-soluble metal salts.
  • the abrasive of Example 2 which did not contain abrasive grains (A), did not show abrasiveness even though the metal salt (B) was in the form of particles.
  • a silicon oxide film was formed. It was shown to improve the polishing rate of silicon nitride films while keeping the polishing rate approximately constant.
  • the cerium oxide of the present invention has a high polishing rate not only for silicon oxide films but also for silicon nitride films. Therefore, for example, in CMP of a surface to be polished on which silicon oxide and silicon nitride are arranged in a pattern, the polishing rate is sufficiently high. While maintaining the above, the silicon oxide film and the silicon nitride can be polished at a uniform speed or adjusted to a desired selectivity. Therefore, the cerium oxide of the present invention is suitable for planarization of insulating films for STI in semiconductor device manufacturing.

Abstract

The present invention provides: a polishing agent which contains cerium oxide and a metal salt, and which is capable of polishing a silicon nitride film at a high speed; and a polishing method.　The present invention provides: a polishing agent which contains (A) abrasive grains, (B) a metal salt that is poorly soluble in water, and water; and a polishing method wherein a surface to be polished and a polishing pad are brought into contact with each other, while supplying the polishing agent thereto, and polishing is carried out by means of a relative motion of the surface to be polished and the polishing pad. With respect to this polishing method, a surface to be polished of a semiconductor substrate and a polishing pad are brought into contact with each other, while supplying a polishing agent for polishing the surface to be polished containing silicon oxide and/or silicon nitride; and polishing is carried out by means of a relative motion of the surface to be polished and the polishing pad.

Description

研磨剤、添加液および研磨方法Polishing agent, additive liquid and polishing method
　本発明は、研磨剤、添加液および研磨方法に関する。 The present invention relates to an abrasive, an additive liquid, and a polishing method.
　近年、半導体集積回路の高集積化や高機能化に伴い、半導体素子の微細化および高密度化のための微細加工技術の開発が進められている。従来から、半導体集積回路装置（以下、半導体デバイスともいう。）の製造においては、層表面の凹凸（段差）がリソグラフィの焦点深度を越えて十分な解像度が得られなくなるなどの問題を防ぐため、化学的機械的平坦化法（Ｃｈｅｍｉｃａｌ　Ｍｅｃｈａｎｉｃａｌ　Ｐｏｌｉｓｈｉｎｇ：以下、ＣＭＰという。）を用いて、層間絶縁膜や埋め込み配線等を平坦化することが行われている。素子の高精細化や微細化の要求が厳しくなるにしたがって、ＣＭＰによる高平坦化の重要性はますます増大している。 In recent years, as semiconductor integrated circuits have become more highly integrated and highly functional, microfabrication technology has been developed to miniaturize and increase the density of semiconductor elements. Conventionally, in the manufacture of semiconductor integrated circuit devices (hereinafter also referred to as semiconductor devices), in order to prevent problems such as unevenness (steps) on a layer surface exceeding the depth of focus of lithography and sufficient resolution not being obtained, 2. Description of the Related Art Chemical mechanical polishing (hereinafter referred to as CMP) is used to planarize interlayer insulating films, embedded wiring, and the like. As the demand for higher definition and miniaturization of devices becomes stricter, the importance of high planarization by CMP is increasing more and more.
　また近年、半導体デバイスの製造において、半導体素子のより高度な微細化を進めるために、素子分離幅の小さいシャロートレンチによる分離法（Ｓｈａｌｌｏｗ　Ｔｒｅｎｃｈ　Ｉｓｏｌａｔｉｏｎ：以下、ＳＴＩという。）が導入されている。
　ＳＴＩは、シリコン基板にトレンチ（溝）を形成し、トレンチ内に絶縁膜を埋め込むことで、電気的に絶縁された素子領域を形成する手法である。図１Ａ、図１Ｂを参照して、ＳＴＩの一例を説明する。図１Ａ、図１Ｂの例ではまず、図１Ａに示すように、シリコン基板１の素子領域を窒化ケイ素膜２等でマスクした後、シリコン基板１にトレンチ３を形成し、トレンチ３を埋めるように酸化ケイ素膜４等の絶縁膜を堆積する。次いで、ＣＭＰによって、凹部であるトレンチ３内の酸化ケイ素膜４を残しながら、凸部である窒化ケイ素膜２上の酸化ケイ素膜４を研磨し除去することで、図１Ｂに示すように、トレンチ３内に酸化ケイ素膜４が埋め込まれた素子分離構造が得られる。 In recent years, in the manufacture of semiconductor devices, an isolation method using a shallow trench isolation (hereinafter referred to as STI) with a small element isolation width has been introduced in order to promote further miniaturization of semiconductor elements.
STI is a method of forming an electrically insulated element region by forming a trench in a silicon substrate and embedding an insulating film in the trench. An example of STI will be described with reference to FIGS. 1A and 1B. In the example of FIGS. 1A and 1B, first, as shown in FIG. 1A, after masking the device region of the silicon substrate 1 with a silicon nitride film 2 or the like, trenches 3 are formed in the silicon substrate 1 and filled in. An insulating film such as a silicon oxide film 4 is deposited. Next, by CMP, the silicon oxide film 4 on the silicon nitride film 2, which is a convex portion, is polished and removed while leaving the silicon oxide film 4 in the trench 3, which is a concave portion. An element isolation structure is obtained in which the silicon oxide film 4 is embedded in the silicon oxide film 3 .
　例えば、特許文献１には、特定の水溶性ポリマーと、酸化セリウム粒子と、水を含有し、ｐＨが４～９の研磨剤が開示されている。当該特許文献１の研磨剤によれば、酸化ケイ素膜に対する高い研磨速度を維持しながら、窒化ケイ素膜に対する研磨速度を低く抑えることができる。図１Ａ、図１Ｂの例では、窒化ケイ素膜２が研磨のストッパー膜となることで、良好な平坦面が得られる。 For example, Patent Document 1 discloses a polishing agent containing a specific water-soluble polymer, cerium oxide particles, and water and having a pH of 4-9. According to the polishing agent of Patent Document 1, the polishing rate for a silicon nitride film can be kept low while maintaining a high polishing rate for a silicon oxide film. In the examples of FIGS. 1A and 1B, the silicon nitride film 2 serves as a polishing stopper film, so that a good flat surface can be obtained.
特開２０１９－８７６６０号公報JP 2019-87660 A
　図２Ａ～図２Ｃを参照して、ＳＴＩの別の一例を説明する。図２Ａ～図２Ｃの例では、図２Ａに示すように、シリコン基板１０の素子領域上に窒化ケイ素膜１３と酸化ケイ素膜１４とが積層した積層体を研磨対象とする。なお図２Ａにおいてシリコン基板１０は結晶性シリコン１１とアモルファスシリコン１２を便宜的に区別しているが、このような構成に限られない。また結晶性シリコン１１とアモルファスシリコン１２の境界は明確でないことがある。
　図２Ａの積層体において、酸化ケイ素膜１４と共に窒化ケイ素膜１３も研磨し除去することが求められることがある（図２Ｃ）。しかしながら従来の研磨剤では一般的に酸化ケイ素膜１４の研磨速度に対し窒化ケイ素膜１３の研磨速度が遅いため、当該研磨剤で研磨を進めると図２Ｃの酸化ケイ素膜１４のくぼみが大きくなる恐れがある。そのため、一旦酸化ケイ素膜１４を研磨した後（図２Ｂ）、酸化ケイ素膜の研磨を抑制する添加剤などを添加した研磨剤を用いて窒化ケイ素膜１３を研磨することが一般的であった。しかしながら当該手法は、研磨プロセスの高速化を妨げるという問題があった。
　ＣＭＰにおいて、十分に高い研磨速度を維持しながら、酸化ケイ素膜と窒化ケイ素とを等速研磨するために、また、窒化ケイ素膜を単独で研磨する観点からも、窒化ケイ素膜を高速に研磨できる研磨剤が求められていた。 Another example of STI is described with reference to FIGS. 2A-2C. In the examples of FIGS. 2A to 2C, as shown in FIG. 2A, a laminated body in which a silicon nitride film 13 and a silicon oxide film 14 are laminated on an element region of a silicon substrate 10 is to be polished. In FIG. 2A, the silicon substrate 10 is divided into crystalline silicon 11 and amorphous silicon 12 for the sake of convenience, but the configuration is not limited to this. Also, the boundary between the crystalline silicon 11 and the amorphous silicon 12 may not be clear.
In the stack of FIG. 2A, it may be desired to polish and remove the silicon nitride film 13 as well as the silicon oxide film 14 (FIG. 2C). However, since the polishing speed of the silicon nitride film 13 is generally lower than that of the silicon oxide film 14 with the conventional polishing agent, the depression of the silicon oxide film 14 shown in FIG. There is Therefore, it was common to polish the silicon nitride film 13 using a polishing agent to which an additive or the like for suppressing the polishing of the silicon oxide film was added after the silicon oxide film 14 was once polished (FIG. 2B). However, this method has a problem of hindering the speeding up of the polishing process.
In CMP, a silicon nitride film can be polished at a high speed in order to uniformly polish a silicon oxide film and a silicon nitride film while maintaining a sufficiently high polishing rate, and also from the viewpoint of polishing a silicon nitride film alone. Abrasives were required.
　本発明は、上記実情に鑑みてなされたものであり、窒化ケイ素膜を高速研磨可能な酸化セリウムと金属塩を含む研磨剤の提供を目的とする。 The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polishing agent containing cerium oxide and a metal salt capable of polishing a silicon nitride film at high speed.
　本発明に係る研磨剤は、砥粒（Ａ）、水に難溶性の金属塩（Ｂ）、および水を含有する。 The abrasive according to the present invention contains abrasive grains (A), a sparingly water-soluble metal salt (B), and water.
　上記研磨剤は、前記金属塩（Ｂ）が、炭酸金属塩、硫酸金属塩、リン酸金属塩、酢酸金属塩およびシュウ酸金属塩からなる群から選択される少なくとも１種の金属塩を含んでいてもよい。 In the abrasive, the metal salt (B) contains at least one metal salt selected from the group consisting of metal carbonate, metal sulfate, metal phosphate, metal acetate and metal oxalate. You can
　上記研磨剤は、前記炭酸金属塩が、炭酸バリウムおよび炭酸ストロンチウムからなる群から選択される少なくも１種の金属塩を含んでいてもよい。 In the polishing agent, the metal carbonate may contain at least one metal salt selected from the group consisting of barium carbonate and strontium carbonate.
　上記研磨剤は、前記硫酸金属塩が、硫酸バリウムおよび硫酸ストロンチウムからなる群から選択される少なくも１種の金属塩を含んでいてもよい。 In the abrasive, the metal sulfate may contain at least one metal salt selected from the group consisting of barium sulfate and strontium sulfate.
　上記研磨剤は、前記金属塩（Ｂ）の含有割合が、研磨剤の全質量に対して０．１質量％以上５質量％以下であってもよい。 The content of the metal salt (B) in the abrasive may be 0.1% by mass or more and 5% by mass or less with respect to the total mass of the abrasive.
　上記研磨剤は、前記金属塩（Ｂ）の含有割合が、前記砥粒（Ａ）に対する質量比（Ｂ／Ａ）で０．１～２０であってもよい。 In the polishing agent, the content of the metal salt (B) may be 0.1 to 20 in mass ratio (B/A) to the abrasive grains (A).
　上記研磨剤は、前記砥粒（Ａ）が、酸化セリウムおよびコロイダルシリカからなる群から選択される少なくとも１種を含んでいてもよい。 In the abrasive, the abrasive grains (A) may contain at least one selected from the group consisting of cerium oxide and colloidal silica.
　本発明に係る添加液は、水に難溶性の金属塩（Ｂ）、分散剤（Ｃ）、および水を含有する。 The additive liquid according to the present invention contains a sparingly water-soluble metal salt (B), a dispersant (C), and water.
　本発明に係る研磨方法は研磨剤を供給しながら被研磨面と研磨パッドを接触させ、両者の相対運動により研磨を行う研磨方法であって、前記研磨剤として上記本発明に係る研磨剤を使用し、半導体基板の酸化ケイ素および／または窒化ケイ素を含む被研磨面を研磨する。 The polishing method according to the present invention is a polishing method in which a surface to be polished and a polishing pad are brought into contact with each other while a polishing agent is supplied, and polishing is performed by relative movement of the two, and the polishing agent according to the present invention is used as the polishing agent. Then, the surface to be polished containing silicon oxide and/or silicon nitride of the semiconductor substrate is polished.
　本発明により、窒化ケイ素膜を高速研磨可能な酸化セリウムを含む研磨剤が提供される。 The present invention provides a polishing agent containing cerium oxide capable of polishing a silicon nitride film at high speed.
従来の研磨方法の一例を示す図であり、研磨対象物の研磨前の状態を示す断面図である。It is a figure which shows an example of the conventional polishing method, and is sectional drawing which shows the state before grinding|polishing of the grinding|polishing target object. 従来の研磨方法の一例を示す図であり、研磨対象物の研磨後の状態を示す断面図である。It is a figure which shows an example of the conventional polishing method, and is sectional drawing which shows the state after grinding|polishing of the grinding|polishing target object. 従来の研磨方法の研磨工程の一例を示す図であり、研磨対象物の研磨前の状態を示す断面図である。It is a figure which shows an example of the grinding|polishing process of the conventional polishing method, and is sectional drawing which shows the state before grinding|polishing of the grinding|polishing target object. 従来の研磨方法の研磨工程の一例を示す図であり、研磨対象物の研磨中の状態を示す断面図である。It is a figure which shows an example of the grinding|polishing process of the conventional polishing method, and is sectional drawing which shows the state during grinding|polishing of the grinding|polishing target object. 従来の研磨方法の研磨工程の一例を示す図であり、研磨対象物の研磨後の状態を示す断面図である。It is a figure which shows an example of the grinding|polishing process of the conventional polishing method, and is sectional drawing which shows the state after grinding|polishing of the grinding|polishing target object. 本発明の研磨方法の一例を示す図であり、研磨対象物の研磨前の状態を示す断面図である。It is a figure which shows an example of the grinding|polishing method of this invention, and is sectional drawing which shows the state before grinding|polishing of the grinding|polishing target object. 本発明の研磨方法の一例を示す図であり、研磨対象物の研磨後の状態を示す断面図である。It is a figure which shows an example of the grinding|polishing method of this invention, and is sectional drawing which shows the state after grinding|polishing of the grinding|polishing target object. 研磨装置の一例を示す模式図である。It is a schematic diagram which shows an example of a polishing apparatus. 金属塩（Ｂ）の作用を説明するための模式的な断面図である。It is a typical sectional view for explaining the action of metal salt (B). 金属塩（Ｂ）の作用を説明するための模式的な断面図である。It is a typical sectional view for explaining the action of metal salt (B).
　以下、本発明の実施形態について説明する。本発明は以下の実施形態に限定されるものではなく、本発明の趣旨に合致する限り、他の実施の形態も本発明の範疇に属し得る。説明を明確にするため、以下の記載及び図面は、適宜、簡略化されている。また、説明のため図面中の各部材は縮尺が大きく異なることがある。 Embodiments of the present invention will be described below. The present invention is not limited to the following embodiments, and other embodiments may also belong to the scope of the present invention as long as they are consistent with the gist of the present invention. For clarity of explanation, the following description and drawings have been simplified where appropriate. Also, for the sake of explanation, the scale of each member in the drawings may differ greatly.
　なお、本発明において「被研磨面」とは、研磨対象物の研磨される面であり、例えば表面を意味する。本明細書においては、半導体デバイスを製造する過程で半導体基板に現れる中間段階の表面も、「被研磨面」に含まれる。
　本発明において「酸化ケイ素」は主に二酸化ケイ素であるが、それに限定されず、二酸化ケイ素以外のケイ素酸化物を含んでいてもよい。
　また、数値範囲を示す「～」は、その前後に記載された数値を下限値および上限値として含む。
　説明を明確にするため、以下の記載および図面は、適宜、簡略化されている。また、説明のため図面中の各部材は縮尺が大きく異なることがある。 In the present invention, the term "surface to be polished" refers to a surface to be polished of an object to be polished, and means, for example, a surface. In this specification, the "surface to be polished" includes an intermediate stage surface appearing on the semiconductor substrate in the process of manufacturing a semiconductor device.
In the present invention, "silicon oxide" is mainly silicon dioxide, but is not limited thereto and may contain silicon oxides other than silicon dioxide.
In addition, "-" indicating a numerical range includes the numerical values described before and after it as a lower limit and an upper limit.
For clarity of explanation, the following description and drawings have been simplified where appropriate. Also, for the sake of explanation, the scale of each member in the drawings may differ greatly.
［研磨剤］
　本発明に係る研磨剤（以下、本研磨剤とも記す。）は、砥粒（Ａ）と、水に難溶性の金属塩（Ｂ）（単に金属塩（Ｂ）とも記す。）、および水を含有し、本発明の効果を奏する範囲で更に他の成分を含有してもよいものである。 [Abrasive]
The abrasive according to the present invention (hereinafter also referred to as the present abrasive) comprises abrasive grains (A), a sparingly water-soluble metal salt (B) (simply referred to as metal salt (B)), and water. It may contain other components as long as the effect of the present invention is exhibited.
＜砥粒（Ａ）＞
　本研磨剤は砥粒（Ａ）を含有する。砥粒としては、ＣＭＰ用の砥粒として用いられるものの中から、適宜選択して用いることができる。窒化ケイ素や酸化ケイ素の研磨速度に優れる点からは、砥粒が金属酸化物粒子であることが好ましい。
　金属酸化物としては、酸化セリウム（セリア）、アルミナ、シリカ、チタニア、ジルコニアからなる群より選択される金属の酸化物が挙げられる。窒化ケイ素や酸化ケイ素の研磨速度に優れる点からは、中でも、酸化セリウムまたはコロイダルシリカが好ましい。なお砥粒（Ａ）は１種類を単独でまたは２種以上を組み合わせて用いることができる。 <Abrasive grain (A)>
This abrasive contains abrasive grains (A). Abrasive grains can be appropriately selected and used from those used as abrasive grains for CMP. The abrasive grains are preferably metal oxide particles from the viewpoint of excellent polishing rate for silicon nitride and silicon oxide.
Metal oxides include metal oxides selected from the group consisting of cerium oxide (ceria), alumina, silica, titania, and zirconia. Among them, cerium oxide or colloidal silica is preferable from the viewpoint of excellent polishing rate of silicon nitride or silicon oxide. The abrasive grains (A) can be used singly or in combination of two or more.
　砥粒用の酸化セリウム粒子は、公知のものから適宜選択して用いることができる。例えば、特開平１１－１２５６１号公報、特開２００１－３５８１８号公報、特表２０１０－５０５７３５号に記載された方法で製造された酸化セリウム粒子が挙げられる。具体的には、硝酸セリウム（ＩＶ）アンモニウム水溶液にアルカリを加えて水酸化セリウムゲルを作製し、これをろ過、洗浄、焼成して得られた酸化セリウム粒子；高純度の炭酸セリウムを粉砕後焼成し、さらに粉砕、分級して得られた酸化セリウム粒子；液中でセリウム（ＩＩＩ）塩を化学的に酸化して得られた酸化セリウム粒子などが挙げられる。 Cerium oxide particles for abrasive grains can be appropriately selected from known ones and used. Examples thereof include cerium oxide particles produced by the methods described in JP-A-11-12561, JP-A-2001-35818, and JP-A-2010-505735. Specifically, cerium oxide particles obtained by adding an alkali to an aqueous solution of cerium(IV) ammonium nitrate to prepare a cerium hydroxide gel, filtering, washing and calcining the gel; , cerium oxide particles obtained by pulverization and classification; and cerium oxide particles obtained by chemically oxidizing cerium (III) salt in liquid.
　砥粒（Ａ）の平均粒子径は、０．０１～０．５μｍが好ましく、０．０３～０．３以下がより好ましい。平均粒子径が０．５μｍ以下であれば、被研磨面に生じるスクラッチ等の研磨キズの発生が抑制される。また、平均粒子径が０．０１μｍ以上であれば、砥粒（Ａ）の粗大な凝集が抑制され研磨剤の保存安定性に優れるとともに、研磨速度にも優れている。
　砥粒（Ａ）は、液中において一次粒子が凝集した凝集粒子（二次粒子）として存在しているので、砥粒（Ａ）の好ましい粒径を、平均二次粒子径で表すものとする。すなわち、上記数値範囲を示した平均粒子径は、通常、平均二次粒子径である。平均二次粒子径は、純水などの分散媒中に分散した分散液を用いて、レーザー回折・散乱式などの粒度分布計を使用して測定される。 The average particle size of the abrasive grains (A) is preferably 0.01-0.5 μm, more preferably 0.03-0.3 μm. If the average particle size is 0.5 μm or less, the occurrence of polishing flaws such as scratches on the surface to be polished is suppressed. Further, when the average particle diameter is 0.01 μm or more, coarse agglomeration of the abrasive grains (A) is suppressed, the storage stability of the abrasive is excellent, and the polishing rate is also excellent.
Since the abrasive grains (A) exist as aggregated particles (secondary particles) in which the primary particles are aggregated in the liquid, the preferred particle size of the abrasive grains (A) is represented by the average secondary particle size. . That is, the average particle size indicated in the above numerical range is usually the average secondary particle size. The average secondary particle size is measured using a particle size distribution meter such as a laser diffraction/scattering type using a dispersion liquid dispersed in a dispersion medium such as pure water.
　砥粒（Ａ）の含有割合（濃度）は、研磨剤全体に対して０．０５～２．０質量％が好ましく、０．１～０．５質量％がより好ましい。砥粒の含有割合が上記下限値以上であれば、優れた研磨速度が得られる。一方、砥粒の含有割合が上記上限値以下であれば、本研磨剤の粘度の上昇が抑制され、取扱い性に優れている。 The content (concentration) of the abrasive grains (A) is preferably 0.05 to 2.0% by mass, more preferably 0.1 to 0.5% by mass, relative to the total abrasive. If the content of abrasive grains is at least the above lower limit, an excellent polishing rate can be obtained. On the other hand, if the content of the abrasive grains is equal to or less than the above upper limit, the increase in viscosity of the present polishing agent is suppressed, and the handleability is excellent.
＜金属塩（Ｂ）＞
　本研磨剤は、水に難溶性の金属塩（Ｂ）を含有することを特徴とする。金属塩（Ｂ）を含有することで窒化ケイ素膜の研磨速度が上昇する作用について発明者は下記のように推定する。
　図５Ａ、図５Ｂは、金属塩（Ｂ）の作用を説明するための模式的な断面図である。本研磨剤は溶媒である水中に砥粒（Ａ）３１と金属塩（Ｂ）３２とが分散している。図５Ａの例において被研磨面である窒化ケイ素膜１３の表面は水と接触することで水和して、窒化ケイ素の一部が酸化ケイ素１３ａに変化していると推定される（図５Ｂ）。金属塩（Ｂ）３２が窒化ケイ素膜１３の表面付近に存在すると当該水和作用が促進されるものと推定される。本研磨剤は当該金属塩（Ｂ）の作用により露出した窒化ケイ素膜１３最表面が順次研磨速度の速い酸化ケイ素に変化していくことで砥粒（Ａ）による研磨速度が上昇するものと推測される。 <Metal salt (B)>
This abrasive is characterized by containing a metal salt (B) that is sparingly soluble in water. The inventor presumes as follows about the effect of increasing the polishing rate of the silicon nitride film by containing the metal salt (B).
5A and 5B are schematic cross-sectional views for explaining the action of the metal salt (B). This abrasive contains abrasive grains (A) 31 and metal salt (B) 32 dispersed in water, which is a solvent. In the example of FIG. 5A, the surface of the silicon nitride film 13, which is the surface to be polished, is hydrated by contact with water, and it is presumed that part of the silicon nitride is changed to silicon oxide 13a (FIG. 5B). . Presumably, the presence of the metal salt (B) 32 near the surface of the silicon nitride film 13 accelerates the hydration. In this polishing agent, it is presumed that the exposed outermost surface of the silicon nitride film 13 is sequentially changed into silicon oxide having a high polishing speed due to the action of the metal salt (B), thereby increasing the polishing speed of the abrasive grains (A). be done.
　本発明の研磨剤において金属塩（Ｂ）、水に難溶性の金属塩を適宜選択して用いることができる。なお本発明において水に難溶性とは、２５℃における溶解度が１ｇ未満であることをいい、好ましくは０．５ｇ以下、より好ましくは０．１ｇ以下であることをいう。 The metal salt (B) and the sparingly water-soluble metal salt can be appropriately selected and used in the abrasive of the present invention. In the present invention, "sparingly soluble in water" means that the solubility at 25°C is less than 1 g, preferably 0.5 g or less, more preferably 0.1 g or less.
　水に難溶性の金属塩（Ｂ）としては、窒化ケイ素膜の研磨速度をより向上する点から、炭酸金属塩、硫酸金属塩、リン酸金属塩、シュウ酸金属塩、酢酸金属塩などが挙げられ、中でも、炭酸金属塩、硫酸金属塩、リン酸金属塩、酢酸金属塩およびシュウ酸金属塩からなる群から選択される少なくとも１種の金属塩を含むことが好ましく、炭酸金属塩または硫酸金属塩がより好ましい。
　また、金属塩（Ｂ）を構成する金属としては、窒化ケイ素膜の研磨速度をより向上する点から、アルカリ土類金属またはランタノイドが好ましく、中でも、バリウム、ストロンチウム、ランタンまたはセリウムが好ましく、バリウムまたはストロンチウムが更に好ましい。 As the sparingly water-soluble metal salt (B), metal carbonate, metal sulfate, metal phosphate, metal oxalate, metal acetate, and the like are mentioned from the viewpoint of further improving the polishing rate of the silicon nitride film. Among them, it is preferable to contain at least one metal salt selected from the group consisting of metal carbonate, metal sulfate, metal phosphate, metal acetate and metal oxalate, and metal carbonate or metal sulfate Salt is more preferred.
Further, the metal constituting the metal salt (B) is preferably an alkaline earth metal or a lanthanide from the viewpoint of further improving the polishing rate of the silicon nitride film. Strontium is more preferred.
　水に難溶性の金属塩（Ｂ）の具体例としては、炭酸バリウム、炭酸ストロンチウム、炭酸ランタン、炭酸セリウム、硫酸バリウム、硫酸ストロンチウム、硫酸ランタン、硫酸セリウム、リン酸バリウム、リン酸ストロンチウム、リン酸ランタン、リン酸セリウム、シュウ酸バリウム、シュウ酸ストロンチウム、シュウ酸ランタン、シュウ酸セリウム、酢酸セリウム（ＩＩＩ）などが挙げられ、窒化ケイ素膜の研磨速度をより向上する点から、中でも、炭酸バリウム、炭酸ストロンチウム、硫酸バリウム、硫酸ストロンチウム、シュウ酸バリウムまたはシュウ酸ストロンチウムが好ましい。なお金属塩（Ｂ）は１種類を単独でまたは２種以上を組み合わせて用いることができる。 Specific examples of the sparingly water-soluble metal salt (B) include barium carbonate, strontium carbonate, lanthanum carbonate, cerium carbonate, barium sulfate, strontium sulfate, lanthanum sulfate, cerium sulfate, barium phosphate, strontium phosphate, and phosphoric acid. Lanthanum, cerium phosphate, barium oxalate, strontium oxalate, lanthanum oxalate, cerium oxalate, cerium (III) acetate, etc., and from the viewpoint of further improving the polishing rate of the silicon nitride film, barium carbonate, Strontium carbonate, barium sulfate, strontium sulfate, barium oxalate or strontium oxalate are preferred. In addition, metal salt (B) can be used individually by 1 type or in combination of 2 or more types.
　金属塩（Ｂ）の平均粒径は特に限定されないが、例えば５ｎｍ～３μｍであればよく１０ｎｍ～２μｍが好ましい。金属塩（Ｂ）の平均粒子径が上記上限値以下であれば、被研磨面に生じるスクラッチ等の研磨キズの発生が抑制される。また、上記下限値以上であれば、金属塩（Ｂ）粗大な凝集が抑制され研磨剤の保存安定性に優れるとともに、研磨速度にも優れている。
　なお金属塩（Ｂ）の平均粒子径の測定方法は、前記砥粒（Ａ）と同様である。 The average particle size of the metal salt (B) is not particularly limited, but may be, for example, 5 nm to 3 μm, preferably 10 nm to 2 μm. When the average particle size of the metal salt (B) is equal to or less than the above upper limit, the occurrence of polishing flaws such as scratches on the surface to be polished is suppressed. Moreover, when the content is at least the above lower limit, coarse agglomeration of the metal salt (B) is suppressed, and the storage stability of the polishing agent is excellent, and the polishing rate is also excellent.
The method for measuring the average particle size of the metal salt (B) is the same as that for the abrasive grains (A).
　金属塩（Ｂ）の含有割合は、窒化ケイ素膜の研磨速度をより向上する点から、本研磨剤の全質量に対して０．１質量％以上５質量％以下であることが好ましい。
　また、金属塩（Ｂ）の含有割合は、窒化ケイ素膜の研磨速度をより向上する点から、前記砥粒（Ａ）に対する質量比（Ｂ／Ａ）で０．１～２０であることが好ましい。 The content of the metal salt (B) is preferably 0.1% by mass or more and 5% by mass or less with respect to the total mass of the polishing agent, from the viewpoint of further improving the polishing rate of the silicon nitride film.
Further, the content of the metal salt (B) is preferably 0.1 to 20 in mass ratio (B/A) to the abrasive grains (A) from the viewpoint of further improving the polishing rate of the silicon nitride film. .
＜水＞
　本発明の研磨剤は、砥粒（Ａ）と金属塩（Ｂ）とを分散させる媒体として水を含有する。水の種類については特に限定されないものの、水溶性ポリマー等への影響、不純物の混入の防止、ｐＨ等への影響を考慮して、純水、超純水、イオン交換水等を用いることが好ましい。 <Water>
The abrasive of the present invention contains water as a medium for dispersing the abrasive grains (A) and the metal salt (B). Although the type of water is not particularly limited, it is preferable to use pure water, ultrapure water, ion-exchanged water, etc. in consideration of effects on water-soluble polymers, etc., prevention of contamination by impurities, effects on pH, etc. .
＜他の成分＞
　本研磨剤は、上記本発明の効果を奏する範囲で、更に他の成分を含有してもよい。他の成分としては、分散剤、ｐＨ調整剤、潤滑剤、ポリマーなどが挙げられる。 <Other ingredients>
The polishing agent may further contain other components within the range in which the effects of the present invention are exhibited. Other ingredients include dispersants, pH modifiers, lubricants, polymers, and the like.
（分散剤（Ｃ））
　分散剤（Ｃ）は、砥粒（Ａ）および／または金属塩（Ｂ）の分散性および分散安定性を向上するために必要に応じて用いられる。分散剤としては、研磨剤用途に用いられる公知のものの中から適宜選択して用いることができ、例えば、陰イオン性、陽イオン性、ノニオン性、両性の界面活性剤や、陰イオン性、陽イオン性、ノニオン性、両性の高分子化合物が挙げられ、これらの１種または２種以上を用いることができる。
　分散剤としては、水溶性の有機高分子や陰イオン性の界面活性剤が好ましい。水溶性の有機高分子としては、カルボキシ基またはカルボン酸アンモニウム塩等を有するポリマーが好ましく、ポリアクリル酸またはポリアクリル酸塩が特に好ましい。
　分散剤（Ｃ）を用いる場合その含有割合は、砥粒（Ａ）および／または金属塩（Ｂ）の分散性および分散安定性の点から、砥粒（Ａ）および金属塩（Ｂ）の合計質量１００質量部に対して０．０００１～１０質量部が好ましく、０．０００１～５質量部がより好ましく、０．００１～１質量部がさらに好ましい。 (Dispersant (C))
A dispersant (C) is optionally used to improve the dispersibility and dispersion stability of the abrasive grains (A) and/or the metal salt (B). As the dispersing agent, it can be used by appropriately selecting from known ones used for abrasive applications. Examples include ionic, nonionic, and amphoteric polymer compounds, and one or more of these can be used.
As the dispersant, a water-soluble organic polymer or an anionic surfactant is preferred. As the water-soluble organic polymer, a polymer having a carboxyl group or a carboxylate ammonium salt or the like is preferable, and polyacrylic acid or polyacrylic acid salt is particularly preferable.
When the dispersant (C) is used, the content ratio is the total of the abrasive grains (A) and the metal salt (B) from the viewpoint of the dispersibility and dispersion stability of the abrasive grains (A) and/or the metal salt (B). It is preferably 0.0001 to 10 parts by mass, more preferably 0.0001 to 5 parts by mass, even more preferably 0.001 to 1 part by mass, based on 100 parts by mass.
（ｐＨ調整剤）
　本研磨剤のｐＨを調節するためにｐＨ調整剤を用いてもよい。ｐＨ調整剤としては、水溶性の無機酸、有機酸、塩基性化合物や、アミノ酸などの両性化合物、およびこれらの塩の中から、適宜選択して用いることができる。
　無機酸としては、例えば、硝酸、硫酸、塩酸、リン酸等が挙げられ、これらのアンモニウム塩、ナトリウム塩、カリウム塩等を用いてもよい。
　有機酸としては、例えば、カルボン酸類、有機スルホン酸類、有機リン酸類などが挙げられ、これらのアンモニウム塩、ナトリウム塩、カリウム塩等を用いてもよい。
　カルボン酸類としては、例えば、酢酸、プロピオン酸、乳酸、酒石酸、シュウ酸、マレイン酸などが挙げられる。有機スルホン酸類としては、例えば、ベンゼンスルホン酸、トシル酸などが挙げられる。また有機リン酸類としては、メチルホスホン酸、ジメチルホスフィン酸などが挙げられる。
　塩基性化合物としては、アンモニア、水酸化カリウム、テトラメチルアンモニウムヒドロキシド、エチレンジアミンなどが挙げられる。
　また、両性化合物としては、グリシン、アラニン、フェニルアラニンなどが挙げられる。 (pH adjuster)
A pH adjuster may be used to adjust the pH of the abrasive. As the pH adjuster, it is possible to appropriately select and use water-soluble inorganic acids, organic acids, basic compounds, amphoteric compounds such as amino acids, and salts thereof.
Examples of inorganic acids include nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, etc., and their ammonium salts, sodium salts, potassium salts, etc. may be used.
Examples of organic acids include carboxylic acids, organic sulfonic acids, organic phosphoric acids and the like, and their ammonium salts, sodium salts, potassium salts and the like may be used.
Examples of carboxylic acids include acetic acid, propionic acid, lactic acid, tartaric acid, oxalic acid, and maleic acid. Examples of organic sulfonic acids include benzenesulfonic acid and tosylic acid. Examples of organic phosphoric acids include methylphosphonic acid and dimethylphosphinic acid.
Basic compounds include ammonia, potassium hydroxide, tetramethylammonium hydroxide, ethylenediamine, and the like.
Amphoteric compounds include glycine, alanine, phenylalanine, and the like.
　本研磨剤のｐＨは３以上１２以下が好ましい。研磨剤のｐＨがこの範囲である場合には、酸化ケイ素膜を高速に研磨しながら、窒化ケイ素膜も高速に研磨するという効果が十分に得られる。窒化ケイ素膜の研磨速度をより向上する点から、研磨剤のｐＨは、４以上１１以下がより好ましく、４．５以上１０以下が特に好ましい。
　ｐＨ調整剤の含有割合は、上記ｐＨになるように適宜調整すればよい。一例として、本研磨剤全体に対して０．００５～２．０質量％とすることができ、０．０１～１．５質量％が好ましく、０．０１～０．３質量％がより好ましい。 The pH of the polishing agent is preferably 3 or more and 12 or less. When the pH of the polishing agent is within this range, the effect of polishing the silicon nitride film at high speed while polishing the silicon oxide film at high speed is sufficiently obtained. The pH of the polishing agent is more preferably 4 or more and 11 or less, and particularly preferably 4.5 or more and 10 or less, from the viewpoint of further improving the polishing rate of the silicon nitride film.
The content of the pH adjuster may be appropriately adjusted so as to achieve the above pH. As an example, it can be 0.005 to 2.0% by mass, preferably 0.01 to 1.5% by mass, more preferably 0.01 to 0.3% by mass, based on the entire polishing agent.
　また上記潤滑剤は、研磨剤の潤滑性を向上し、研磨速度の面内均一性を向上させるために必要に応じて用いられる。潤滑剤の例として、ポリエチレングリコール、ポリグリセリンなどの水溶性高分子が挙げられる。 In addition, the lubricant is used as necessary to improve the lubricity of the polishing agent and improve the in-plane uniformity of the polishing rate. Examples of lubricants include water-soluble polymers such as polyethylene glycol and polyglycerin.
（ζ電位）
　本研磨剤のζ電位は、絶対値で３０ｍＶ以上が好ましい。研磨剤のζ電位がこの範囲である場合には、分散安定性を維持しながら、窒化ケイ素膜も高速に研磨するという効果が十分に得られる。研磨剤のζ電位は、絶対値で４０ｍＶ以上がより好ましく、絶対値で５０ｍＶ以上が特に好ましい。
　なおζ電位は、上記分散剤等を選択することにより調整することができる。 (ζ potential)
The absolute value of the .zeta.-potential of the abrasive is preferably 30 mV or more. When the .zeta.-potential of the polishing agent is within this range, the effect of polishing the silicon nitride film at high speed while maintaining the dispersion stability is sufficiently obtained. The ζ potential of the abrasive is more preferably 40 mV or more in absolute value, and particularly preferably 50 mV or more in absolute value.
Note that the .zeta.-potential can be adjusted by selecting the above dispersant or the like.
＜本研磨剤の調製方法＞
　本研磨剤の調製方法は、媒体である水中に、砥粒（Ａ）、水に難溶性の金属塩（Ｂ）と必要に応じて用いられる各成分が均一に分散ないし溶解する方法の中から適宜選択すればよい。
　例えば、水に難溶性の金属塩（Ｂ）、分散剤（Ｃ）、および水を含有する研磨液と、砥粒（Ａ）を含むスラリーとをそれぞれ準備し、これらを混合することで本研磨剤を調製することが好ましい。本研磨剤は研磨装置内で上記混合を行って用時調製してもよい。 <Method for preparing the present abrasive>
The preparation method of this polishing agent is selected from among the methods of uniformly dispersing or dissolving the abrasive grains (A), the sparingly water-soluble metal salt (B), and optional components in water, which is a medium. It can be selected as appropriate.
For example, a polishing liquid containing a sparingly water-soluble metal salt (B), a dispersant (C), and water, and a slurry containing abrasive grains (A) are separately prepared, and these are mixed to perform the main polishing. Preparation of agents is preferred. The polishing agent may be prepared just before use by carrying out the above-described mixing in a polishing apparatus.
　本発明の研磨剤は、保管や輸送の利便性のため、砥粒の分散液（以下、分散液αともいう。）と、水に難溶性の金属塩（Ｂ）、分散剤（Ｃ）、および水を含有する分散液（以下、分散液βともいう。）の２液として、別々に準備し、使用時に混合してもよい。なお、この分散液βが、以下に示す研磨用添加液である。
＜研磨用添加液＞
　本発明の（研磨用）添加液は、砥粒の分散液（上記の分散液α）と混合して研磨剤を調製するための添加液であって、水に難溶性の金属塩（Ｂ）、分散剤（Ｃ）と、水を含有する。研磨剤の調製において、この研磨用添加液を用いることで、研磨剤の保管や輸送の利便性を向上させることができる。
　本発明の研磨用添加液において、水に難溶性の金属塩（Ｂ）、分散剤（Ｃ）、および水については、前記研磨剤に含有される各成分および液のｐＨについて記載したものと同様である。
　本発明の研磨用添加液において、水に難溶性の金属塩（Ｂ）の含有割合（濃度）は、特に限定されないが、添加液の取り扱いのし易さや、砥粒の分散液との混合のし易さの観点から、添加液の全量に対して０．１質量％以上１０質量％以下が好ましい。
　本発明の研磨用添加液において、分散剤（Ｃ）の含有割合（濃度）は、特に限定されないが、添加液の取り扱いのし易さや、砥粒の分散液との混合のし易さの観点から、添加液の全量に対して０．１質量％以上１０質量％以下が好ましい。
　このような研磨用添加液と混合される砥粒の分散液において、液中の砥粒の含有割合（濃度）は、砥粒の分散性および分散液の取り扱いのし易さ等の観点から、０．０１質量％以上４０質量％以下が好ましい。０．０１質量％以上２０質量％以下がより好ましく、０．０１質量％以上１０質量％以下が特に好ましい。
　本発明の研磨用添加液を、砥粒の分散液と混合することで、酸化ケイ素膜に対する十分に高い平坦性を維持しながら、酸化ケイ素膜と窒化ケイ素とを共に高速研磨する前記研磨剤を実現することができる。なお、研磨用添加液と砥粒の分散液との混合においては、研磨用添加液を砥粒の分散液に添加して混合してもよいし、研磨用添加液に砥粒の分散液を添加して混合してもよい。 For convenience in storage and transportation, the abrasive of the present invention comprises a dispersion of abrasive grains (hereinafter also referred to as dispersion α), a sparingly water-soluble metal salt (B), a dispersant (C), and a water-containing dispersion (hereinafter also referred to as dispersion β) may be separately prepared and mixed at the time of use. This dispersion β is the additive liquid for polishing described below.
<Additive liquid for polishing>
The (polishing) additive liquid of the present invention is an additive liquid for preparing a polishing agent by mixing with a dispersion liquid of abrasive grains (dispersion liquid α described above), and comprises a sparingly water-soluble metal salt (B) , dispersant (C) and water. By using this additive liquid for polishing in the preparation of a polishing agent, the convenience of storing and transporting the polishing agent can be improved.
In the polishing additive solution of the present invention, the sparingly water-soluble metal salt (B), dispersant (C), and water are the same as those described for each component contained in the polishing agent and the pH of the solution. is.
In the polishing additive solution of the present invention, the content (concentration) of the sparingly water-soluble metal salt (B) is not particularly limited. From the viewpoint of ease of application, it is preferably 0.1% by mass or more and 10% by mass or less with respect to the total amount of the additive liquid.
In the additive liquid for polishing of the present invention, the content ratio (concentration) of the dispersant (C) is not particularly limited, but from the viewpoint of ease of handling of the additive liquid and ease of mixing with the dispersion liquid of abrasive grains. Therefore, it is preferably 0.1% by mass or more and 10% by mass or less with respect to the total amount of the additive liquid.
In the dispersion liquid of abrasive grains mixed with such a polishing additive liquid, the content ratio (concentration) of the abrasive grains in the liquid is determined from the viewpoint of dispersibility of the abrasive grains and ease of handling of the dispersion liquid. 0.01 mass % or more and 40 mass % or less are preferable. 0.01% by mass or more and 20% by mass or less is more preferable, and 0.01% by mass or more and 10% by mass or less is particularly preferable.
By mixing the additive liquid for polishing of the present invention with a dispersion liquid of abrasive grains, the above-described polishing agent that polishes both the silicon oxide film and the silicon nitride at a high speed while maintaining sufficiently high flatness of the silicon oxide film is obtained. can be realized. In the mixing of the polishing additive liquid and the abrasive grain dispersion liquid, the polishing additive liquid may be added to the abrasive grain dispersion liquid and mixed, or the abrasive grain dispersion liquid may be added to the polishing additive liquid. You may add and mix.
　研磨用添加液と砥粒の分散液との混合比率は、特に限定されず、混合後の研磨剤において、水に難溶性の金属塩（Ｂ）、分散剤（Ｃ）、および水の含有割合（濃度）が、研磨剤の全量に対して、それぞれ研磨剤の全質量に対して０．１質量％以上５質量％以下および０．０００２質量％以上２質量％以下となる混合比率が好ましい。研磨用添加液および砥粒の分散液の混合のし易さの観点からは、研磨用添加液：砥粒の分散液＝１３０：１～１：１３０の質量比率で混合することが好ましい。
　本発明の研磨剤は、必ずしも予め構成する研磨成分をすべて混合したものとして、研磨の場に供給する必要はない。研磨の場に供給する際に、研磨成分が混合されて研磨剤の組成になってもよい。
　本発明の研磨剤は、保管や輸送の利便性のため、砥粒の分散液（分散液α）と、上記の研磨用添加液（分散液β）の２液として別々に準備し、使用時に混合してもよい。分散液αと分散液βとの２液に分け、これらを混合して研磨剤を調製する場合は、上記のように、分散液βにおける水に難溶性の金属塩（Ｂ）、分散剤（Ｃ）、および水の濃度を、研磨剤使用時の例えば１０倍程度に濃縮しておき、混合後所定の濃度になるように水で希釈してから使用してもよい。 The mixing ratio of the polishing additive liquid and the dispersion liquid of abrasive grains is not particularly limited. (Concentration) is preferably 0.1% by mass or more and 5% by mass or less and 0.0002% by mass or more and 2% by mass or less with respect to the total mass of the abrasive. From the standpoint of ease of mixing the additive liquid for polishing and the dispersion liquid of abrasive grains, it is preferable to mix the additive liquid for polishing and the dispersion liquid of abrasive grains at a mass ratio of 130:1 to 1:130.
The abrasive of the present invention does not necessarily have to be supplied to the polishing site as a mixture of all constituent polishing components in advance. When supplied to the polishing station, the polishing components may be mixed into the composition of the abrasive.
For the convenience of storage and transportation, the abrasive of the present invention is prepared separately as two liquids, a dispersion of abrasive grains (dispersion α) and the above polishing additive liquid (dispersion β). May be mixed. When the abrasive is prepared by dividing the two liquids of the dispersion liquid α and the dispersion liquid β and mixing them, as described above, the sparingly water-soluble metal salt (B) and the dispersing agent ( The concentration of C) and water may be concentrated to, for example, about 10 times the concentration of the abrasive when used, and after mixing, diluted with water to a predetermined concentration before use.
［本研磨剤を用いた研磨方法］
　本研磨剤を用いた研磨方法としては、例えば、本研磨剤を供給しながら研磨対象物の被研磨面と研磨パッドとを接触させ、両者の相対運動により研磨を行う方法が挙げられる。
　ここで、研磨が行われる被研磨面は、例えば、半導体基板の表面に窒化ケイ素膜と酸化ケイ素膜とが積層されたブランケットウェハ、およびこれらの膜種がパターン状に配置されたパターンウェハなどが挙げられる。
　本研磨方法によれば、例えば、図３Ａに示すように、シリコン基板１０の素子領域上に窒化ケイ素膜１３と酸化ケイ素膜１４とが積層した積層体を研磨対象とし、１段階の研磨工程により、窒化ケイ素膜１３と酸化ケイ素膜１４とを研磨することも可能である（図３Ｂ）。 [Polishing method using the present abrasive]
As a polishing method using the present polishing agent, for example, there is a method in which the surface to be polished of the object to be polished and the polishing pad are brought into contact while supplying the present polishing agent, and polishing is performed by relative movement of the two.
Here, the surface to be polished includes, for example, a blanket wafer in which a silicon nitride film and a silicon oxide film are laminated on the surface of a semiconductor substrate, a pattern wafer in which these film types are arranged in a pattern, and the like. mentioned.
According to this polishing method, for example, as shown in FIG. 3A, a laminate obtained by laminating a silicon nitride film 13 and a silicon oxide film 14 on an element region of a silicon substrate 10 is to be polished. , it is also possible to polish the silicon nitride film 13 and the silicon oxide film 14 (FIG. 3B).
　ＳＴＩ用基板における酸化ケイ素膜としては、テトラエトキシシラン（ＴＥＯＳ）を原料にしてプラズマＣＶＤ法で成膜された、いわゆるＰＥ－ＴＥＯＳ膜が挙げられる。また、酸化ケイ素膜として、高密度プラズマＣＶＤ法で成膜された、いわゆるＨＤＰ膜を挙げることができる。また、その他のＣＶＤ法で成膜されたＨＡＲＰ膜やＦＣＶＤ膜、スピンコートで製膜されるＳＯＤ膜を使用することもできる。窒化ケイ素膜としては、シランまたはジクロロシランとアンモニアを原料として、低圧ＣＶＤ法やプラズマＣＶＤ法で成膜したものやＡＬＤ法で成膜したものが挙げられる。 A so-called PE-TEOS film, which is formed by plasma CVD using tetraethoxysilane (TEOS) as a raw material, can be used as the silicon oxide film on the STI substrate. Moreover, as a silicon oxide film, a so-called HDP film formed by a high-density plasma CVD method can be mentioned. A HARP film or FCVD film formed by other CVD methods, or an SOD film formed by spin coating can also be used. Examples of the silicon nitride film include those formed by low-pressure CVD, plasma CVD, and ALD using silane or dichlorosilane and ammonia as raw materials.
　本研磨方法には、公知の研磨装置を使用できる。図４は、研磨装置の一例を示す模式図である。図４の例に示す研磨装置２０は、ＳＴＩ基板のような半導体基板２１を保持する研磨ヘッド２２と、研磨定盤２３と、研磨定盤２３の表面に貼り付けられた研磨パッド２４と、研磨パッド２４に研磨剤２５を供給する研磨剤供給配管２６とを備えている。研磨剤供給配管２６から研磨剤２５を供給しながら、研磨ヘッド２２に保持された半導体基板２１の被研磨面を研磨パッド２４に接触させ、研磨ヘッド２２と研磨定盤２３とを相対的に回転運動させて研磨を行うように構成されている。 A known polishing apparatus can be used for this polishing method. FIG. 4 is a schematic diagram showing an example of a polishing apparatus. The polishing apparatus 20 shown in the example of FIG. 4 includes a polishing head 22 holding a semiconductor substrate 21 such as an STI substrate, a polishing surface plate 23, a polishing pad 24 attached to the surface of the polishing surface plate 23, and a polishing surface. and an abrasive supply pipe 26 for supplying an abrasive 25 to the pad 24 . The surface to be polished of the semiconductor substrate 21 held by the polishing head 22 is brought into contact with the polishing pad 24 while the polishing agent 25 is being supplied from the polishing agent supply pipe 26, and the polishing head 22 and the polishing platen 23 are relatively rotated. It is configured to be moved and polished.
　研磨ヘッド２２は、回転運動だけでなく直線運動をしてもよい。また、研磨定盤２３および研磨パッド２４は、半導体基板２１と同程度またはそれ以下の大きさであってもよい。その場合は、研磨ヘッド２２と研磨定盤２３とを相対的に移動させることにより、半導体基板２１の被研磨面の全面を研磨できるようにすることが好ましい。さらに、研磨定盤２３および研磨パッド２４は回転運動を行うものでなくてもよく、例えばベルト式で一方向に移動するものであってもよい。 The polishing head 22 may perform linear motion as well as rotational motion. Also, the polishing surface plate 23 and the polishing pad 24 may be of the same size as or smaller than the semiconductor substrate 21 . In that case, it is preferable to polish the entire surface of the semiconductor substrate 21 to be polished by relatively moving the polishing head 22 and the polishing platen 23 . Furthermore, the polishing platen 23 and the polishing pad 24 may not be rotating, and may be belt-type and move in one direction.
　このような研磨装置２０の研磨条件には特に制限はないが、研磨ヘッド２２に荷重をかけて研磨パッド２４に押し付けることでより研磨圧力を高め、研磨速度を向上させることができる。研磨圧力は０．５～５０ｋＰａ程度が好ましく、研磨速度における半導体基板２１の被研磨面内の均一性、平坦性、スクラッチなどの研磨欠陥防止の観点から、３～４０ｋＰａ程度がより好ましい。研磨定盤２３および研磨ヘッド２２の回転数は、５０～５００ｒｐｍ程度が好ましい。また、研磨剤２５の供給量については、研磨剤の組成や上記各研磨条件等により適宜調整される。 The polishing conditions of the polishing apparatus 20 are not particularly limited, but by applying a load to the polishing head 22 and pressing it against the polishing pad 24, the polishing pressure can be increased and the polishing speed can be improved. The polishing pressure is preferably about 0.5 to 50 kPa, and more preferably about 3 to 40 kPa from the viewpoint of uniformity and flatness of the polishing rate in the surface to be polished of the semiconductor substrate 21, and prevention of polishing defects such as scratches. The number of revolutions of the polishing surface plate 23 and the polishing head 22 is preferably about 50 to 500 rpm. Further, the supply amount of the polishing agent 25 is appropriately adjusted depending on the composition of the polishing agent, the above polishing conditions, and the like.
　研磨パッド２４としては、不織布、発泡ポリウレタン、多孔質樹脂、非多孔質樹脂などからなるものを使用することができる。研磨パッド２４への研磨剤２５の供給を促進し、あるいは研磨パッド２４に研磨剤２５が一定量溜まるようにするために、研磨パッド２４の表面に格子状、同心円状、らせん状などの溝加工を施してもよい。また、必要に応じて、パッドコンディショナーを研磨パッド２４の表面に接触させて、研磨パッド２４表面のコンディショニングを行いながら研磨してもよい。 As the polishing pad 24, one made of non-woven fabric, foamed polyurethane, porous resin, non-porous resin, or the like can be used. In order to promote the supply of the polishing agent 25 to the polishing pad 24 or to allow a certain amount of the polishing agent 25 to accumulate in the polishing pad 24, the surface of the polishing pad 24 is grooved in a lattice, concentric, spiral, or the like. may be applied. If necessary, a pad conditioner may be brought into contact with the surface of the polishing pad 24 to condition the surface of the polishing pad 24 while polishing.
　以下、本発明を実施例および比較例により具体的に説明するが、本発明はこれらの実施例に限定されるものではない。以下の例において、「％」は、特に断らない限り質量％を意味する。また、特性値は下記の方法により測定し評価した。なお、例１～２は比較例であり、例３～例１５は実施例である。 Although the present invention will be specifically described below with reference to examples and comparative examples, the present invention is not limited to these examples. In the following examples, "%" means % by mass unless otherwise specified. Moreover, the characteristic values were measured and evaluated by the following methods. Examples 1 and 2 are comparative examples, and Examples 3 to 15 are examples.
［ｐＨ］
　ｐＨは、東亜ディーケーケー社製のｐＨメータＨＭ－３０Ｒを使用して測定した。 [pH]
The pH was measured using a pH meter HM-30R manufactured by DKK Toa.
［ζ電位］
　ζ電位は、協和界面科学株式会社製ＺｅｔａＰｒｏｂｅを使用して測定した。 [ζ potential]
The ζ potential was measured using ZetaProbe manufactured by Kyowa Interface Science Co., Ltd.
［研磨特性］
　研磨特性は、全自動ＣＭＰ研磨装置（Ａｐｐｌｉｅｄ　Ｍａｔｅｒｉａｌｓ社製、装置名：Ｍｉｒｒａ）を用いて以下の研磨を行い評価した。研磨パッドは、２層ポリウレタンパッド（ＳｈｏｒｅＤ値が６５のもの）を使用し、研磨パッドのコンディショニングには、ＣＶＤダイヤモンドパッドコンディショナー（Ｋｉｎｉｋ社製、商品名：Ｐｙｒａｄｉａ　１７９Ｂ）を使用した。研磨条件は、研磨圧力を２１ｋＰａ、研磨定盤の回転数を７７ｒｐｍ、研磨ヘッドの回転数を７３ｒｐｍとした。また、研磨剤の供給速度は２００ミリリットル／分とした。 [Polishing characteristics]
Polishing characteristics were evaluated by performing the following polishing using a fully automatic CMP polishing apparatus (manufactured by Applied Materials, apparatus name: Mirra). A two-layer polyurethane pad (with a Shore D value of 65) was used as the polishing pad, and a CVD diamond pad conditioner (manufactured by Kinik, trade name: Pyradia 179B) was used for conditioning the polishing pad. The polishing conditions were a polishing pressure of 21 kPa, a polishing platen rotation speed of 77 rpm, and a polishing head rotation speed of 73 rpm. Also, the supply rate of the abrasive was set to 200 ml/min.
［研磨速度測定装置］
　各膜の膜厚の測定には、ＫＬＡ－Ｔｅｎｃｏｒ社の膜厚計ＵＶ－１２８０ＳＥを使用し、研磨時間と膜厚の変化から研磨速度（研磨レート）を算出した。 [Polishing speed measuring device]
A film thickness meter UV-1280SE manufactured by KLA-Tencor was used to measure the film thickness of each film, and the polishing speed (polishing rate) was calculated from changes in polishing time and film thickness.
［例１：研磨剤の調製］
　平均粒子径が１００ｎｍの酸化セリウム約３０ｇを、純水２７０ｍＬを含む容器に入れ、超音波ホモジナイザーを５分間照射し、解砕、分散処理を施した。次に噴射衝突処理を５回繰り返して行い、解砕、分散処理を施して、酸化セリウムが分散したスラリーを得た。超音波ホモジナイザーは、ＮＩＨＯＮＳＥＩＫＩ　ＫＡＩＳＨＡ社製のＵＳ－６００ＴＣＶＰ（装置名）を使用し、湿式ジェットミルはスギノマシン社製のスターバーストミニ（装置名）を使用した。得られた１０％の酸化セリウムスラリーを希釈して例１の研磨剤とした。 [Example 1: Preparation of abrasive]
About 30 g of cerium oxide having an average particle size of 100 nm was placed in a container containing 270 mL of pure water, and irradiated with an ultrasonic homogenizer for 5 minutes to be pulverized and dispersed. Next, the injection collision treatment was repeated five times, followed by pulverization and dispersion treatment to obtain slurry in which cerium oxide was dispersed. US-600TCVP (apparatus name) manufactured by NIHONSEIKI KAISHA was used as an ultrasonic homogenizer, and Starburst Mini (apparatus name) manufactured by Sugino Machine was used as a wet jet mill. The resulting 10% cerium oxide slurry was diluted to form the Example 1 abrasive.
［例２：研磨剤の調製］
　炭酸バリウム（関東化学株式会社製）約３０ｇを、純水２７０ｍＬを含む容器に入れ、超音波ホモジナイザーを５分間照射し、解砕、分散剤（ポリアクリル酸アンモニウム）を用いて分散処理を施した。次に噴射衝突処理を５回繰り返して行い、解砕、分散処理を施して、炭酸バリウムが分散したスラリーを得た。得られた１０％の炭酸バリウムスラリーを希釈して例２の研磨剤とした。例３～例１２の金属塩（Ｂ）も同様の分散処理を行った。 [Example 2: Preparation of abrasive]
About 30 g of barium carbonate (manufactured by Kanto Kagaku Co., Ltd.) was placed in a container containing 270 mL of pure water, irradiated with an ultrasonic homogenizer for 5 minutes, crushed, and dispersed using a dispersant (ammonium polyacrylate). . Next, the injection collision treatment was repeated five times, followed by pulverization and dispersion treatment to obtain a slurry in which barium carbonate was dispersed. The resulting 10% barium carbonate slurry was diluted to form the Example 2 abrasive. The metal salts (B) of Examples 3 to 12 were also subjected to the same dispersion treatment.
［例３：研磨剤の調製］
　例１の研磨剤に炭酸ランタンとして３．０ｇになるように炭酸ランタン八水和物（関東化学株式会社製）を入れたスラリーを作製した。得られた酸化セリウムスラリーを希釈して例３の研磨剤とした。 [Example 3: Preparation of abrasive]
A slurry was prepared by adding 3.0 g of lanthanum carbonate octahydrate (manufactured by Kanto Kagaku Co., Ltd.) to the polishing agent of Example 1. The resulting cerium oxide slurry was diluted to form the polishing agent of Example 3.
［例４：研磨剤の調製］
　例１の研磨剤に炭酸セリウムとして３．０ｇになるように炭酸セリウム八水和物（関東化学株式会社製）を入れたスラリーを作製した。得られた酸化セリウムスラリーを希釈し例４の研磨剤とした。 [Example 4: Preparation of abrasive]
A slurry was prepared by adding cerium carbonate octahydrate (manufactured by Kanto Kagaku Co., Ltd.) to the abrasive of Example 1 so that the amount of cerium carbonate was 3.0 g. The obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 4.
［例５：研磨剤の調製］
　例１の研磨剤に炭酸バリウム（関東化学株式会社製）３．０ｇを入れたスラリーを作製した。得られた酸化セリウムスラリーを希釈し例５の研磨剤とした。 [Example 5: Preparation of abrasive]
A slurry was prepared by adding 3.0 g of barium carbonate (manufactured by Kanto Kagaku Co., Ltd.) to the polishing agent of Example 1. The obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 5.
［例６：研磨剤の調製］
　例１の研磨剤に炭酸バリウム（関東化学株式会社製）１．５ｇを入れたスラリーを作製した。得られた酸化セリウムスラリーを希釈し例６の研磨剤とした。 [Example 6: Preparation of abrasive]
A slurry was prepared by adding 1.5 g of barium carbonate (manufactured by Kanto Kagaku Co., Ltd.) to the abrasive of Example 1. The obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 6.
［例７：研磨剤の調製］
　例１の研磨剤に炭酸バリウム（関東化学株式会社製）０．３ｇを入れたスラリーを作製した。得られた酸化セリウムスラリーを希釈して例７の研磨剤とした。 [Example 7: Preparation of abrasive]
A slurry was prepared by adding 0.3 g of barium carbonate (manufactured by Kanto Kagaku Co., Ltd.) to the polishing agent of Example 1. The obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 7.
［例８：研磨剤の調製］
　例１の研磨剤に炭酸バリウムＢＷ－ＫＨ３０（堺化学工業株式会社製）３．０ｇを入れたスラリーを作製した。得られた酸化セリウムスラリーを希釈して例８の研磨剤とした。 [Example 8: Preparation of abrasive]
A slurry was prepared by adding 3.0 g of barium carbonate BW-KH30 (manufactured by Sakai Chemical Industry Co., Ltd.) to the abrasive of Example 1. The resulting cerium oxide slurry was diluted to obtain the polishing agent of Example 8.
［例９：研磨剤の調製］
　例１の研磨剤に炭酸ストロンチウムＳＷ－Ｋ４０（堺化学工業株式会社製）３．０ｇを入れたスラリーを作製した。得られた酸化セリウムスラリーを希釈して例９の研磨剤とした。 [Example 9: Preparation of abrasive]
A slurry was prepared by adding 3.0 g of strontium carbonate SW-K40 (manufactured by Sakai Chemical Industry Co., Ltd.) to the abrasive of Example 1. The obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 9.
［例１０：研磨剤の調製］
　例８の研磨剤に硝酸水溶液を適量加えｐＨ４．５に調整したスラリーを作製した。得られた酸化セリウムスラリーを希釈して例１０の研磨剤とした。 [Example 10: Preparation of abrasive]
A slurry was prepared by adding an appropriate amount of an aqueous nitric acid solution to the polishing agent of Example 8 and adjusting the pH to 4.5. The resulting cerium oxide slurry was diluted to form the polishing agent of Example 10.
［例１１：研磨剤の調製］
　例８の研磨剤に水酸化カリウム水溶液を適量加えｐＨ１０に調整したスラリーを作製した。得られた酸化セリウムスラリーを希釈して例１１の研磨剤とした。 [Example 11: Preparation of abrasive]
A slurry was prepared by adjusting the pH to 10 by adding an appropriate amount of an aqueous potassium hydroxide solution to the polishing agent of Example 8. The resulting cerium oxide slurry was diluted to form the polishing agent of Example 11.
［例１２：研磨剤の調製］
　例１の研磨剤に硫酸ストロンチウム（関東化学株式会社製）３．０ｇを入れたスラリーを作製した。得られた酸化セリウムスラリーを希釈し例１２の研磨剤とした。 [Example 12: Preparation of abrasive]
A slurry was prepared by adding 3.0 g of strontium sulfate (manufactured by Kanto Kagaku Co., Ltd.) to the polishing agent of Example 1. The obtained cerium oxide slurry was diluted to obtain the polishing agent of Example 12.
［例１３：研磨剤の調製］
　例１の研磨剤にシュウ酸ストロンチウム（関東化学株式会社製）３．０ｇを入れたスラリーを作製した。得られた酸化セリウムスラリーを例１３の研磨剤とした。 [Example 13: Preparation of abrasive]
A slurry was prepared by adding 3.0 g of strontium oxalate (manufactured by Kanto Kagaku Co., Ltd.) to the abrasive of Example 1. The obtained cerium oxide slurry was used as the polishing agent of Example 13.
［例１４：研磨剤の調製］
　例１の研磨剤にシュウ酸バリウム（関東化学株式会社製）３．０ｇを入れたスラリーを作製した。得られた酸化セリウムスラリーを例１４の研磨剤とした。 [Example 14: Preparation of abrasive]
A slurry was prepared by adding 3.0 g of barium oxalate (manufactured by Kanto Kagaku Co., Ltd.) to the polishing agent of Example 1. The resulting cerium oxide slurry was used as the polishing agent of Example 14.
［例１５：研磨剤の調製］
　例１の研磨剤にリン酸バリウム（関東化学株式会社製）３．０ｇを入れたスラリーを作製した。得られた酸化セリウムスラリーを例１５の研磨剤とした。 [Example 15: Preparation of abrasive]
A slurry was prepared by adding 3.0 g of barium phosphate (manufactured by Kanto Kagaku Co., Ltd.) to the abrasive of Example 1. The resulting cerium oxide slurry was used as the polishing agent of Example 15.
　各例の研磨液を用い、上述の方法で酸化ケイ素膜および窒化ケイ素膜をそれぞれ研磨し、研磨レートを測定した。結果を表１に示す。 Using the polishing solution of each example, the silicon oxide film and the silicon nitride film were each polished by the method described above, and the polishing rate was measured. Table 1 shows the results.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　例２～例１２及び例１３～例１５の金属塩（Ｂ）はいずれも水に難溶性の金属塩である。砥粒（Ａ）を含有しない例２の研磨剤は、金属塩（Ｂ）が粒子状であっても研磨性を示さなかった。例１と例３～例１２及び例１３～例１５との比較により示されるとおり、砥粒（Ａ）と水に難溶性の金属塩（Ｂ）とを組み合わせて用いることにより、酸化ケイ素膜の研磨速度を概ね一定に保持しながら窒化ケイ素膜の研磨速度を向上することが示された。 All of the metal salts (B) of Examples 2 to 12 and Examples 13 to 15 are sparingly water-soluble metal salts. The abrasive of Example 2, which did not contain abrasive grains (A), did not show abrasiveness even though the metal salt (B) was in the form of particles. As shown by comparison between Example 1 and Examples 3 to 12 and Examples 13 to 15, by using a combination of abrasive grains (A) and a sparingly water-soluble metal salt (B), a silicon oxide film was formed. It was shown to improve the polishing rate of silicon nitride films while keeping the polishing rate approximately constant.
　本発明の酸化セリウムは、酸化ケイ素膜だけでなく、窒化ケイ素膜の研磨速度も高いため、例えば、酸化ケイ素と窒化ケイ素がパターン状に配置された被研磨面のＣＭＰにおいて、十分に高い研磨速度を維持しながら、酸化ケイ素膜と窒化ケイ素とを等速研磨、あるいは所望の選択比に調整して研磨を行うことができる。したがって、本発明の酸化セリウムは、半導体デバイス製造におけるＳＴＩ用絶縁膜の平坦化に適している。 The cerium oxide of the present invention has a high polishing rate not only for silicon oxide films but also for silicon nitride films. Therefore, for example, in CMP of a surface to be polished on which silicon oxide and silicon nitride are arranged in a pattern, the polishing rate is sufficiently high. While maintaining the above, the silicon oxide film and the silicon nitride can be polished at a uniform speed or adjusted to a desired selectivity. Therefore, the cerium oxide of the present invention is suitable for planarization of insulating films for STI in semiconductor device manufacturing.
　この出願は、２０２１年１１月４日に出願された日本出願特願２０２１－１８００４９を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2021-180049 filed on November 4, 2021, and the entire disclosure thereof is incorporated herein.
　１…シリコン基板、２…窒化ケイ素膜、３…トレンチ、４…酸化ケイ素膜、１０…シリコン基板、１１…結晶性シリコン、１２…アモルファスシリコン、１３…窒化ケイ素膜、１３ａ…酸化ケイ素、１４…酸化ケイ素膜、２０…研磨装置、２１…半導体基板、２２…研磨ヘッド、２３…研磨定盤、２４…研磨パッド、２５…研磨剤、２６…研磨剤供給配管、３１…砥粒（Ａ）、３２…金属塩（Ｂ）。 DESCRIPTION OF SYMBOLS 1... Silicon substrate 2... Silicon nitride film 3... Trench 4... Silicon oxide film 10... Silicon substrate 11... Crystalline silicon 12... Amorphous silicon 13... Silicon nitride film 13a... Silicon oxide 14... Silicon oxide film 20 Polishing device 21 Semiconductor substrate 22 Polishing head 23 Polishing surface plate 24 Polishing pad 25 Polishing agent 26 Polishing agent supply pipe 31 Abrasive grain (A) 32... Metal salt (B).

Claims (9)

  1. 　砥粒（Ａ）、水に難溶性の金属塩（Ｂ）、および水を含有する研磨剤。 Abrasives containing abrasive grains (A), water-insoluble metal salts (B), and water.
  2. 　前記金属塩（Ｂ）が、炭酸金属塩、硫酸金属塩、リン酸金属塩、酢酸金属塩およびシュウ酸金属塩からなる群から選択される少なくとも１種の金属塩を含む、請求項１に記載の研磨剤。 2. The method according to claim 1, wherein said metal salt (B) comprises at least one metal salt selected from the group consisting of metal carbonate, metal sulfate, metal phosphate, metal acetate and metal oxalate. Abrasives.
  3. 　前記炭酸金属塩が、炭酸バリウムおよび炭酸ストロンチウムからなる群から選択される少なくも１種の金属塩を含む、請求項２に記載の研磨剤。 The abrasive according to claim 2, wherein the metal carbonate contains at least one metal salt selected from the group consisting of barium carbonate and strontium carbonate.
  4. 　前記硫酸金属塩が、硫酸バリウムおよび硫酸ストロンチウムからなる群から選択される少なくも１種の金属塩を含む、請求項２に記載の研磨剤。 The abrasive according to claim 2, wherein the metal sulfate contains at least one metal salt selected from the group consisting of barium sulfate and strontium sulfate.
  5. 　前記金属塩（Ｂ）の含有割合が、研磨剤の全質量に対して０．１質量％以上５質量％以下である、請求項１～４のいずれか一項に記載の研磨剤。 The abrasive according to any one of claims 1 to 4, wherein the content of the metal salt (B) is 0.1% by mass or more and 5% by mass or less with respect to the total mass of the abrasive.
  6. 　前記金属塩（Ｂ）の含有割合が、前記砥粒（Ａ）に対する質量比（Ｂ／Ａ）で０．１～２０である、請求項１～５のいずれか一項に記載の研磨剤。 The abrasive according to any one of claims 1 to 5, wherein the content of the metal salt (B) is 0.1 to 20 in mass ratio (B/A) to the abrasive grains (A).
  7. 　前記砥粒（Ａ）が、酸化セリウムおよびコロイダルシリカからなる群から選択される少なくとも１種を含む、請求項１～６のいずれか一項に記載の研磨剤。 The abrasive according to any one of claims 1 to 6, wherein the abrasive grains (A) contain at least one selected from the group consisting of cerium oxide and colloidal silica.
  8. 　水に難溶性の金属塩（Ｂ）、分散剤（Ｃ）、および水を含有する添加液。 An additive liquid containing a sparingly water-soluble metal salt (B), a dispersant (C), and water.
  9. 　研磨剤を供給しながら被研磨面と研磨パッドを接触させ、両者の相対運動により研磨を行う研磨方法であって、前記研磨剤として請求項１～７のいずれか一項に記載の研磨剤を使用し、半導体基板の酸化ケイ素および／または窒化ケイ素を含む被研磨面を研磨する研磨方法。 A polishing method in which a surface to be polished and a polishing pad are brought into contact with each other while a polishing agent is being supplied, and polishing is performed by relative movement of the two, wherein the polishing agent according to any one of claims 1 to 7 is used as the polishing agent. A polishing method for polishing a surface to be polished of a semiconductor substrate containing silicon oxide and/or silicon nitride.
PCT/JP2022/039682 2021-11-04 2022-10-25 Polishing agent, additive liquid and polishing method WO2023080014A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0922887A (en) * 1995-07-04 1997-01-21 Fujitsu Ltd Abrasive, polishing method, and manufacture of semiconductor device
JP2003059868A (en) * 2001-08-10 2003-02-28 Hitachi Chem Co Ltd Cmp abrasive and method of polishing board
JP2005503678A (en) * 2001-09-24 2005-02-03 キャボット マイクロエレクトロニクス コーポレイション CMP process based on rare earth salts / oxidants
WO2018179062A1 (en) * 2017-03-27 2018-10-04 日立化成株式会社 Polishing liquid, polishing liquid set, additive liquid, and polishing method
JP2021158278A (en) * 2020-03-27 2021-10-07 株式会社フジミインコーポレーテッド Polishing composition, method for manufacturing polishing composition, polishing method, and method for manufacturing semiconductor substrate

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0922887A (en) * 1995-07-04 1997-01-21 Fujitsu Ltd Abrasive, polishing method, and manufacture of semiconductor device
JP2003059868A (en) * 2001-08-10 2003-02-28 Hitachi Chem Co Ltd Cmp abrasive and method of polishing board
JP2005503678A (en) * 2001-09-24 2005-02-03 キャボット マイクロエレクトロニクス コーポレイション CMP process based on rare earth salts / oxidants
WO2018179062A1 (en) * 2017-03-27 2018-10-04 日立化成株式会社 Polishing liquid, polishing liquid set, additive liquid, and polishing method
JP2021158278A (en) * 2020-03-27 2021-10-07 株式会社フジミインコーポレーテッド Polishing composition, method for manufacturing polishing composition, polishing method, and method for manufacturing semiconductor substrate

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