WO2018100686A1 - Suspension, liquide de polissage, procédé de production de ladite suspension, procédé de production dudit liquide de polissage, et procédé de polissage de substrat - Google Patents

Suspension, liquide de polissage, procédé de production de ladite suspension, procédé de production dudit liquide de polissage, et procédé de polissage de substrat Download PDF

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Publication number
WO2018100686A1
WO2018100686A1 PCT/JP2016/085589 JP2016085589W WO2018100686A1 WO 2018100686 A1 WO2018100686 A1 WO 2018100686A1 JP 2016085589 W JP2016085589 W JP 2016085589W WO 2018100686 A1 WO2018100686 A1 WO 2018100686A1
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polishing
ceria
polishing liquid
slurry
particles
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PCT/JP2016/085589
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English (en)
Japanese (ja)
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春仙 玉田
敬太 荒川
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日立化成株式会社
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Priority to PCT/JP2016/085589 priority Critical patent/WO2018100686A1/fr
Publication of WO2018100686A1 publication Critical patent/WO2018100686A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting

Definitions

  • the present invention relates to a slurry, a polishing liquid, a manufacturing method thereof, and a polishing method for a substrate.
  • CMP Chemical Mechanical Polishing
  • an inorganic insulating film such as a silicon oxide film is formed by a method such as plasma-CVD (chemical vapor deposition) or low-pressure CVD (chemical vapor deposition).
  • a chemical mechanical polishing liquid for planarizing the inorganic insulating film it has been generally studied to use a fumed silica-based polishing liquid.
  • the fumed silica-based polishing liquid is produced by adjusting the pH of a slurry containing particles obtained by grain growth by a method such as thermal decomposition of tetrachlorosilicic acid.
  • a fumed silica-based polishing liquid has a technical problem that the polishing rate is low.
  • STI is used for element isolation in the integrated circuit.
  • a CMP technique using a colloidal silica-based polishing liquid is used to remove an excess silicon oxide film formed on the substrate.
  • a stopper film having a low polishing rate is formed under the silicon oxide film.
  • a silicon nitride film or the like is used for the stopper film.
  • it is desirable that the ratio of the polishing rate of the silicon oxide film to the polishing rate of the stopper film is large.
  • the conventional colloidal silica-based polishing liquid does not have a characteristic that can withstand practical use for STI.
  • a cerium oxide-based polishing liquid containing cerium oxide particles is used as a polishing liquid for glass surfaces such as photomasks and lenses.
  • the hardness of cerium oxide particles is lower than the hardness of silica particles and alumina particles. Therefore, when a cerium oxide-based polishing liquid containing cerium oxide particles is used, the polishing surface is less likely to be damaged when polishing compared to the case where a polishing liquid containing silica particles or alumina particles is used.
  • This polishing liquid is useful for finish mirror polishing.
  • the cerium oxide-based polishing liquid has an advantage that the polishing rate is faster than silica-based polishing liquids such as fumed silica type and colloidal silica type.
  • Patent Document 1 discloses an abrasive having a volume average particle diameter of 1 nm to 95 nm and a number of particles having a diameter of 0.56 ⁇ m or more of 1 million or less per ml.
  • a polishing liquid for CMP process characterized by comprising water is disclosed.
  • Patent Document 2 discloses a cerium oxide abrasive containing a slurry in which cerium oxide particles having a particle diameter of more than 10 nm and less than 100 nm of primary particles of 90% or more are dispersed in a medium. Yes.
  • the present invention has been made in view of such circumstances, and obtains a polishing liquid that has an excellent polishing rate compared to a polishing liquid containing ceria particles having the same average primary particle diameter, and the polishing liquid. It is an object of the present invention to provide a slurry that can be used, a manufacturing method thereof, and a method of polishing a substrate using the polishing liquid.
  • the present invention is a method for producing a slurry containing ceria particles and water, comprising a crushing step of crushing colloidal ceria dispersed in water to obtain ceria particles.
  • This is a slurry production method in which grinding is performed so that the ratio of the average primary particle diameter of ceria particles to the average primary particle diameter of ceria is less than 0.8.
  • the present invention is a method for producing a slurry containing ceria particles and water, comprising a crushing step of crushing colloidal ceria dispersed in water to obtain ceria particles.
  • This is a slurry manufacturing method in which crushing is performed so that the ratio of sphericity of ceria particles to sphericity of ceria is 0.97 or less.
  • the colloidal ceria may be pulverized using a bead mill.
  • the colloidal ceria may be pulverized using a jet mill.
  • the present invention is a method for producing a polishing liquid containing ceria particles, water, and an additive, wherein the slurry obtained by the above production method is mixed with an additive to obtain a polishing liquid.
  • a method for producing a polishing liquid is a method for producing a polishing liquid.
  • the present invention is a slurry obtained by the above-described slurry manufacturing method.
  • the present invention is a polishing liquid obtained by the above polishing liquid manufacturing method.
  • the present invention is a method for polishing a substrate, comprising a polishing step of polishing a film to be polished formed on the surface of the substrate using the polishing liquid.
  • a polishing liquid having an excellent polishing rate, a slurry constituting the polishing liquid, a manufacturing method thereof, and the polishing A method for polishing a substrate using a liquid can be provided.
  • slurry means a composition containing at least ceria particles (abrasive grains) and water
  • polishing liquid means a composition containing at least ceria particles (abrasive grains), additives and water.
  • the slurry manufacturing method according to the present embodiment is a slurry manufacturing method containing ceria particles and water.
  • colloidal ceria is prepared (preparation process).
  • the colloidal ceria may be, for example, a known one obtained through a process of growing ceria crystals by a liquid phase method. Examples of the liquid phase method include (1) sol-gel method, (2) hydrothermal synthesis method, and (3) precipitation method. Colloidal ceria may be obtained by any method.
  • the average primary particle diameter of colloidal ceria is, for example, 10 to 200 nm.
  • the average primary particle diameter of colloidal ceria is calculated
  • the average secondary particle diameter of colloidal ceria is, for example, 20 to 600 nm.
  • the average secondary particle size of colloidal ceria is a value of D50 (median diameter of volume distribution, cumulative median value) measured using a laser diffraction particle size distribution analyzer (for example, product name: Master Sizer Microplus manufactured by Malvern). ).
  • a sample obtained by diluting the colloidal ceria dispersion to a concentration at which the measurement transmittance (H) with respect to the He—Ne laser is 60 to 70% is used. Measurement is performed under the conditions of laser and absorption: 0.
  • the sphericity of colloidal ceria is, for example, 60 to 100%.
  • the sphericity of colloidal ceria is calculated
  • S (%) r / R ⁇ 100 (1)
  • r indicates the maximum radius (nm) of a circle that can be drawn in one colloidal ceria grain in an image obtained by SEM observation
  • R includes one colloidal ceria grain in the image obtained by SEM observation.
  • the sphericity of 50 colloidal ceria randomly selected from the image of colloidal ceria obtained by SEM observation is similarly determined, and the average value thereof is defined as the sphericity of the colloidal ceria.
  • colloidal ceria dispersed in water is pulverized to obtain ceria particles (pulverization step).
  • colloidal ceria pulverized through a pulverization step is referred to as ceria particles.
  • the method for pulverizing colloidal ceria is not particularly limited.
  • the colloidal ceria may be pulverized using, for example, a bead mill or pulverized using a jet mill.
  • a bead mill first, beads having a hardness equal to or higher than that of a substance to be pulverized (colloidal ceria) are filled in a container (pulverization chamber) for pulverization. After filling, the beads are moved by rotating the rotating shaft in the center of the grinding chamber.
  • colloidal ceria dispersed in water (colloidal ceria aqueous dispersion, also referred to as “water dispersion”) is sent to the grinding chamber, colliding the beads with the colloidal ceria, and grinding the colloidal ceria to crush the colloidal ceria. .
  • colloidal ceria water dispersion of colloidal ceria
  • colloidal ceria water dispersion of colloidal ceria
  • water dispersion of colloidal ceria water dispersion of colloidal ceria
  • colloidal ceria is pulverized by colliding a colloidal ceria with a substance having hardness equal to or higher than that of colloidal ceria.
  • the shape of the substance to be collided is not particularly limited, and examples thereof include a spherical shape, a cylindrical shape, and a lump shape.
  • the substance to be collided is preferably a dispersion in which colloidal ceria is dispersed.
  • the ratio of the average primary particle diameter of the ceria particles to the average primary particle diameter of the colloidal ceria is less than 0.8. So that colloidal ceria is crushed.
  • the ratio of the average primary particle diameter of the ceria particles to the average primary particle diameter of the colloidal ceria may be 0.79 or less, 0.78 or less, or 0.70 or less, for example, 0.10 or more. .
  • the average primary particle diameter of the ceria particles is preferably 5 to 250 nm, more preferably 10 to 200 nm, and still more preferably 10 to 150 nm. If the average primary particle diameter of the ceria particles is 5 nm or more, a better polishing rate tends to be obtained. If the average primary particle size of the ceria particles is 250 nm or less, the film to be polished tends not to be damaged.
  • the measuring method of the average primary particle diameter of ceria particles is the same as the measuring method of the average primary particle diameter of colloidal ceria.
  • the average secondary particle size of the ceria particles is preferably 10 to 500 nm, more preferably 20 to 400 nm, and still more preferably 50 to 300 nm. If the average secondary particle diameter of the ceria particles is 10 nm or more, a better polishing rate tends to be obtained. If the average secondary particle diameter of the ceria particles is 500 nm or less, the film to be polished tends to be hardly damaged.
  • the measuring method of the average secondary particle diameter of ceria particles is the same as the measuring method of the average secondary particle diameter of colloidal ceria.
  • the ratio of the sphericity of the ceria particles to the sphericity of the colloidal ceria is 0.97 or less in the grinding step.
  • Crush colloidal ceria The ratio of the sphericity of the ceria particles to the sphericity of the colloidal ceria may be 0.965 or less, 0.96 or less, or 0.955 or less, for example, 0.30 or more.
  • the sphericity of the ceria particles is, for example, 30 to 90%, 35 to 85%, or 40 to 80%.
  • the method for measuring the sphericity of ceria particles is the same as the method for measuring the sphericity of colloidal ceria.
  • colloidal ceria before pulverization is a regular crystal shape, for example, a shape close to a tetrahedron, a hexahedron, a true sphere, etc., whereas the shape of the crushed colloidal ceria is particularly undefined. Shape.
  • the ceria particles after pulverization may contain colloidal ceria remaining without being pulverized. Moreover, you may mix a ceria particle and the colloidal ceria before a grinding
  • an additive Before the pulverization step, an additive may be added to the aqueous dispersion containing colloidal ceria to mix them. Further, after the pulverization step, an additive may be added to the aqueous dispersion containing ceria particles to mix them.
  • the additive used here may be the same as the additive used for the polishing liquid described later. Examples of the mixing method of the colloidal ceria and the additive and the mixing method of the ceria particles and the additive include a mixing method using stirring, a homogenizer, an ultrasonic disperser, or the like.
  • the ratio of the average primary particle diameter of the ceria particles to the average primary particle diameter of the colloidal ceria is less than 0.8, or the sphericity of the ceria particles relative to the sphericity of the colloidal ceria.
  • the method for producing a polishing liquid according to this embodiment is a method for producing a polishing liquid containing ceria particles, water, and an additive, and the slurry obtained by the above production method is mixed with the additive and polished.
  • a step of obtaining a liquid (additive mixing step) is provided.
  • the method for mixing the slurry and the additive include the same method as the method for mixing the colloidal ceria and the additive and the method for mixing the ceria particles and the additive.
  • the content of the ceria particles is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, based on the total amount of the polishing liquid, from the viewpoint of obtaining a good polishing rate.
  • the content of the ceria particles is preferably 20% by mass or less, more preferably 5% by mass or less, and still more preferably 1.5% by mass from the viewpoint that aggregation of the ceria particles is suppressed and the film to be polished is hardly damaged. It is as follows.
  • the additive examples include a dispersant that increases the dispersibility of abrasive grains, a polishing rate improver that improves the polishing rate, a flattening agent (a flattening agent that reduces unevenness of the polished surface after polishing, a substrate after polishing, For example, a global planarizing agent for improving the global planarity), and a selectivity improving agent for improving the polishing selectivity of the inorganic insulating film with respect to the stopper film such as a silicon nitride film and a polysilicon film.
  • a dispersant that increases the dispersibility of abrasive grains
  • a polishing rate improver that improves the polishing rate
  • a flattening agent a flattening agent that reduces unevenness of the polished surface after polishing, a substrate after polishing
  • a global planarizing agent for improving the global planarity
  • a selectivity improving agent for improving the polishing selectivity of the inorganic insulating film with respect to the stopper film
  • Examples of the dispersant for enhancing the dispersibility of the abrasive grains include a water-soluble anionic dispersant, a water-soluble nonionic dispersant, a water-soluble cationic dispersant, and a water-soluble amphoteric dispersant.
  • the dispersant for enhancing the dispersibility of the abrasive grains is preferably a water-soluble anionic dispersant.
  • the dispersant may be one kind of these, or a mixture of two or more kinds.
  • the water-soluble anionic dispersant is preferably a polymer compound containing acrylic acid as a copolymerization component and a salt thereof, more preferably a salt of the polymer compound.
  • the polymer compound containing acrylic acid as a copolymerization component and a salt thereof include, for example, polyacrylic acid and an ammonium salt thereof, a copolymer of acrylic acid and methacrylic acid and an ammonium salt thereof, and acrylic acid amide and acrylic acid. And copolymers thereof and ammonium salts thereof.
  • water-soluble anionic dispersants include, for example, lauryl sulfate triethanolamine, ammonium lauryl sulfate, polyoxyethylene alkyl ether sulfate triethanolamine, and special polycarboxylic acid type polymer dispersants.
  • water-soluble nonionic dispersant examples include polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyethylene glycol monooleate, polyoxyethylene alkylamine, polyoxyethylene hydrogenated castor oil, 2 -Hydroxyethyl methacrylate and alkyl alkanolamides.
  • water-soluble cationic dispersant examples include polyvinyl pyrrolidone, coconut amine acetate, and stearyl amine acetate.
  • water-soluble amphoteric dispersant examples include lauryl betaine, stearyl betaine, lauryl dimethylamine oxide and 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine.
  • Examples of the dispersant other than the above include a polymer compound having at least one selected from the group consisting of a carboxylic acid group and a carboxylic acid group.
  • the polymer compound is preferably a polymer obtained by polymerizing a monomer containing at least one selected from the group consisting of acrylic acid and methacrylic acid, or a salt thereof.
  • Examples of the polymer or a salt thereof include acrylic acid homopolymer (polyacrylic acid), methacrylic acid homopolymer (polymethacrylic acid), a copolymer of acrylic acid and methacrylic acid, acrylic acid or methacrylic acid and Examples include at least one selected from the group consisting of copolymers with other monomers, copolymers of acrylic acid and methacrylic acid with other monomers, and salts thereof.
  • An ammonium acid is mentioned.
  • the content of the dispersant is preferably 0.001 to 10% by mass on the basis of the total amount of the polishing liquid from the viewpoint of improving the dispersibility of the ceria particles to suppress sedimentation and further reducing polishing scratches on the film to be polished. .
  • the weight average molecular weight of the polymer is not particularly limited, but is preferably 100 to 150,000, more preferably 1000 to 20000.
  • the weight average molecular weight of the polymer is 100 or more, a better polishing rate tends to be easily obtained when a film to be polished such as a silicon oxide film or a silicon nitride film is polished.
  • the weight average molecular weight of the polymer is 150,000 or less, the storage stability of the polishing liquid tends to be difficult to decrease.
  • the weight average molecular weight is a value measured by GPC and converted based on standard polyoxyethylene.
  • the method for producing a polishing liquid may further include a step (mixing step) of mixing ceria particles and water.
  • a step (mixing step) of mixing ceria particles and water examples include the same method as the mixing method of the colloidal ceria and the additive and the mixing method of the ceria particles and the additive.
  • Water is not particularly limited, but preferably includes deionized water, ion-exchanged water, ultrapure water, and the like. It suffices if water is contained in the polishing liquid, and the content of water may be the remainder of the polishing liquid excluding the content of other components, and is not particularly limited.
  • the polishing liquid may further contain a solvent other than water as necessary. Examples of the solvent other than water include polar solvents such as ethanol and acetone.
  • the pH of the polishing liquid at room temperature (25 ° C.) is, for example, 4.0 or more and 8.0 or less.
  • the pH of the polishing liquid is preferably 4.5 or more, more preferably 4.8 or more.
  • the pH of the polishing liquid is 8.0 or less, the flatness improving effect tends to be sufficiently exhibited.
  • the pH of the polishing liquid is preferably 7.5 or less, more preferably 7.0 or less.
  • the pH of the polishing liquid is determined by measuring with a pH meter (for example, Model PH81 (trade name) manufactured by Yokogawa Electric Corporation).
  • the pH of the polishing solution is 2 using, for example, a standard buffer solution (phthalate pH buffer solution, pH: 4.21 (25 ° C.), neutral phosphate pH buffer solution, pH 6.86 (25 ° C.)).
  • a standard buffer solution phthalate pH buffer solution, pH: 4.21 (25 ° C.), neutral phosphate pH buffer solution, pH 6.86 (25 ° C.)
  • the electrode is put into a polishing liquid and measured as a value after being stabilized at 25 ° C. for 2 minutes or more.
  • the ratio of the average primary particle diameter of the ceria particles to the average primary particle diameter of the colloidal ceria is less than 0.8, or the spheres of the ceria particles with respect to the sphericity of the colloidal ceria
  • the polishing liquid according to this embodiment is preferably used for polishing a film to be polished, which will be described later, and is also preferably used for shallow trench isolation.
  • the polishing liquid according to the present embodiment may be stored as a one-part polishing liquid containing ceria particles, an additive, and water, and a ceria particle dispersion (first liquid) containing ceria particles, a dispersant, and water; And an additive liquid (second liquid) containing an additive other than the dispersant and water, and may be stored as a two-component polishing liquid.
  • the polishing liquid is preferably stored as a two-part polishing liquid.
  • additives other than the dispersant may be contained in the ceria particle dispersion.
  • planarization characteristics and polishing rate can be adjusted by arbitrarily changing the blend of these two liquids.
  • the polishing liquid may be stored as a two-part polishing liquid composed of a first liquid containing ceria particles and water and a second liquid containing an additive and water.
  • a two-part polishing liquid composed of a first liquid containing ceria particles and water and a second liquid containing an additive and water.
  • the slurry and polishing liquid according to the present embodiment is a slurry storage liquid that is used after being diluted with a liquid medium such as water at the time of use, for example, by a factor of 2 or more, from the viewpoint of suppressing costs related to storage, transportation, storage, and the like. Or it can be stored as a stock solution for polishing liquid.
  • the dilution rate of the stock solution is preferably 2 times or more, more preferably 3 times or more, from the viewpoint that the higher the magnification, the higher the cost-saving effect related to storage, transportation, storage and the like.
  • the upper limit of the dilution ratio of the stock solution is not particularly limited, but from the viewpoint of increasing the amount of components contained in the stock solution (higher concentration) and lowering the stability during storage as the magnification increases. In general, it is preferably 10 times or less, more preferably 7 times or less, and still more preferably 5 times or less. In addition, you may divide a structural component into 3 or more liquids, and also in that case, the dilution rate is the same as the above.
  • substrate polishing method Next, a method for polishing a substrate according to the present embodiment will be described.
  • a substrate on which a film to be polished is formed is prepared (substrate preparing step).
  • the substrate on which the film to be polished is formed is obtained, for example, by forming a film to be polished on the substrate by a low-pressure CVD method, a plasma CVD method, or the like, which will be described later.
  • Examples of the substrate include a substrate (semiconductor substrate) for manufacturing a semiconductor element.
  • Examples of the substrate related to the manufacture of the semiconductor element include a semiconductor substrate in which an inorganic insulating film is formed on the semiconductor substrate. For example, the semiconductor substrate in the stage where the circuit element and the wiring pattern are formed, the stage in which the circuit element is formed And the like.
  • Examples of the film to be polished include interlayer insulating films, BPSG films (silicon dioxide films doped with boron and phosphorus), STI formation films, and the like.
  • Examples of the interlayer insulating film include inorganic insulating films.
  • Examples of the inorganic insulating film include a silicon oxide film, a silicon nitride film, a composite film of a silicon oxide film, and the like.
  • the polishing film formed on the substrate surface is polished using the polishing liquid (polishing step). More specifically, for example, while the polishing film formed on the substrate surface is pressed against the polishing pad of the polishing surface plate, the polishing liquid is supplied between the polishing film and the polishing pad while the polishing liquid is being supplied between the polishing film and the polishing pad.
  • the film to be polished is polished by moving the disk relatively.
  • the ceria particle dispersion and additive liquid are sent through separate pipes, and these pipes are merged just before the outlet of the supply pipe to mix the two liquids, thereby polishing the pad.
  • the ceria particle dispersion liquid and the additive liquid may be mixed immediately before polishing.
  • a polishing liquid When using a stock solution for polishing liquid, a polishing liquid may be obtained by diluting the stock solution for polishing liquid with a liquid medium before the polishing step (stock solution diluting step).
  • the polishing liquid is obtained, for example, by supplying a polishing storage liquid and a liquid medium onto a polishing pad and diluting the polishing liquid on the polishing pad.
  • the storage liquid for polishing liquid in the polishing process, the film to be polished is polished using the polishing liquid obtained in the storage liquid dilution process.
  • the polishing liquid may be adjusted to a desired pH before the polishing step (pH adjustment step).
  • the pH is adjusted by, for example, a pH adjuster.
  • a pH adjuster for example, an acid and a base are mentioned.
  • the acid include nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, boric acid, and acetic acid.
  • the base include sodium hydroxide, ammonia, potassium hydroxide and calcium hydroxide.
  • the base is preferably ammonia.
  • the pH adjuster include ammonium salts of water-soluble polymers that have been partially neutralized with ammonia in advance.
  • the method for polishing a substrate by polishing the film to be polished using the above polishing liquid, unevenness on the surface of the film to be polished (for example, an inorganic insulating film) is eliminated, and the entire surface of the substrate is removed. A smooth surface can be obtained.
  • unevenness on the surface of the film to be polished for example, an inorganic insulating film
  • a substrate on which an inorganic insulating film is formed is prepared (first step).
  • the substrate on which the inorganic insulating film is formed can be obtained, for example, by forming an inorganic insulating film on the substrate by a low pressure CVD method, a plasma CVD method or the like.
  • the inorganic insulating film examples include a silicon oxide film and a silicon nitride film.
  • the silicon oxide film may be doped with elements such as phosphorus and boron.
  • the silicon oxide film In the formation of the silicon oxide film by the low pressure CVD method, monosilane: SiH 4 is used as the Si source, and oxygen: O 2 is used as the oxygen source.
  • SiH 4 —O 2 -based oxidation reaction By performing the SiH 4 —O 2 -based oxidation reaction at a low temperature of 400 ° C. or lower, a silicon oxide film can be obtained.
  • the silicon oxide film obtained by the low temperature CVD method is heat-treated at a temperature of 1000 ° C. or lower.
  • the silicon oxide film is doped with phosphorus: P in order to achieve surface planarization by high-temperature reflow, the silicon oxide film is preferably doped with phosphorus using a SiH 4 —O 2 —PH 3 based reaction gas.
  • Formation of a silicon oxide film by plasma CVD has an advantage that a chemical reaction requiring a high temperature can be performed at a low temperature under normal thermal equilibrium.
  • the plasma generation method there are two methods of capacitive coupling type and inductive coupling type.
  • the reaction gases SiH 4 as an Si source, SiH 4 -N 2 O-containing gas using N 2 O as oxygen source, and TEOS-O-based gas using tetraethoxysilane (TEOS) in an Si source (TEOS- Plasma CVD method).
  • the substrate temperature is preferably 250 to 400 ° C.
  • the reaction pressure is preferably 67 to 400 Pa.
  • SiH 2 Cl 2 —NH 3 oxidation reaction By performing the SiH 2 Cl 2 —NH 3 oxidation reaction at a high temperature of 900 ° C., a silicon nitride film can be obtained.
  • reaction gas used for forming the silicon nitride film by the plasma CVD method examples include SiH 4 —NH 3 based gas using SiH 4 as the Si source and NH 3 as the nitrogen source.
  • the substrate temperature is preferably 300 to 400 ° C.
  • the substrate on which the inorganic insulating film is formed is placed in a polishing apparatus (second step).
  • the substrate is arranged so that the inorganic insulating film on the substrate faces the polishing pad of the polishing apparatus.
  • a polishing apparatus As a polishing apparatus, a general polishing apparatus having a holder for holding a substrate such as a semiconductor substrate having a film to be polished, a motor capable of changing the number of rotations, and a polishing surface plate to which a polishing pad (polishing cloth) can be attached Is mentioned.
  • the polishing apparatus include polishing apparatuses manufactured by Ebara Corporation: F-REX, MIRRA manufactured by AMAT, and Reflexion.
  • the polishing pad is not particularly limited, and examples thereof include general nonwoven fabrics, foamed polyurethane, and porous fluororesins.
  • the polishing pad is preferably grooved so that the polishing liquid is accumulated.
  • the film to be polished is polished using the polishing liquid (third step).
  • the method for polishing the film to be polished is the same as the method for polishing the film to be polished in the polishing step.
  • the polishing liquid is continuously supplied to the polishing pad with a pump or the like during polishing.
  • Polishing conditions are not limited.
  • the rotation speed of the polishing platen is preferably a low rotation of 200 rotations / minute or less so that the semiconductor substrate does not jump out.
  • the pressure (processing load) applied to the semiconductor substrate is preferably 100 kPa or less so as not to cause scratches after polishing.
  • the supply amount of the polishing liquid is not particularly limited, but is preferably such an amount that the surface of the polishing pad is always covered with the polishing liquid.
  • the polished substrate may be washed and dried (cleaning and drying step).
  • the substrate is thoroughly washed in running water, for example, and then dried by removing water droplets adhering to the substrate using a spin dryer or the like.
  • the method for polishing a substrate it is possible to obtain a high polishing rate by polishing the film to be polished using the above polishing liquid (the film to be polished can be quickly polished).
  • polishing an inorganic insulating film, which is a film to be polished, with the above-described polishing liquid surface irregularities can be eliminated and the entire surface of the substrate can be made smooth.
  • the substrate polishing method according to the present embodiment can be applied not only to polishing an inorganic insulating film formed on a semiconductor substrate but also to manufacturing processes of various semiconductor devices.
  • the substrate polishing method according to the present embodiment includes, for example, a silicon oxide film formed on a wiring board having predetermined wiring, an inorganic insulating film such as glass and silicon nitride, polysilicon, Al, Cu, Ti, TiN, W , Optical glass such as photomasks, lenses and prisms, inorganic conductive films such as ITO, optical integrated circuits, optical switching elements, optical waveguides, optical fibers Polishing of the end face of the substrate, optical single crystal such as scintillator, solid laser single crystal, sapphire substrate for blue laser LED, semiconductor single crystal such as SiC, GaP and GaAs, glass substrate for magnetic disk, magnetic head, etc. Can be applied.
  • the semiconductor substrate is manufactured as follows, for example. First, a flattened shallow trench is formed, then a metal wiring such as aluminum is formed on the inorganic insulating film, and an inorganic insulating film is formed again between and on the wiring. Thereafter, the inorganic insulating film is polished using a polishing liquid to obtain a smooth surface. By repeating these steps a predetermined number of times, a semiconductor substrate having a desired number of layers can be obtained.
  • Example 1 (Production of slurry) An aqueous dispersion containing colloidal ceria having an average primary particle diameter of 90 nm and an average secondary particle diameter of 213 nm was prepared. The bead mill treatment was performed for 100 minutes, and colloidal ceria was pulverized until the average primary particle size was 50 nm and the average secondary particle size was 145 nm, to obtain a slurry containing ceria particles (ground abrasive grains) and water.
  • the ratio R2 / R1 of the average primary particle diameter (R2) of the ceria particles to the average primary particle diameter (R1) of the colloidal ceria is 0.56
  • the sphericity S of the ceria particles relative to the sphericity S a of the colloidal ceria the ratio S b / S a and b were crushed colloidal ceria as 0.95 or less.
  • Colloidal ceria before the bead mill treatment and ceria particles after the bead mill treatment were observed with an SEM. The obtained image is shown in FIG.
  • the average primary particle size of colloidal silica before pulverization and ceria particles after pulverization was determined by image analysis by SEM observation. That is, first, an image of ceria particles was obtained by SEM observation, and the obtained image of ceria particles was approximated by a circle, and the diameter of the circle was measured as the primary particle diameter. The primary particle diameters of 50 particles randomly selected from the image of the particles obtained by SEM observation were measured, and the average value was defined as the average primary particle diameter.
  • the average secondary particle size of the ceria particles contained in the slurry was measured using a laser diffraction particle size distribution meter (trade name: Master Sizer Microplus manufactured by Malvern). That is, first, the slurry for measurement was obtained by diluting the slurry to a concentration at which the measurement transmittance (H) for the He—Ne laser was 60 to 70%. The value of D50 obtained by measurement under the conditions of a refractive index of 1.93, a light source He—Ne laser, and zero absorption was taken as the average secondary particle diameter.
  • the sphericity of colloidal ceria before pulverization and ceria particles after pulverization was determined as follows. That is, first, image analysis by SEM observation was performed, and the true sphericity was obtained by the following formula (1).
  • S (%) r / R ⁇ 100 (1)
  • S represents the sphericity ratio (%)
  • r represents the maximum radius of a circle that can be drawn in one particle obtained by SEM observation
  • R represents one particle obtained by SEM observation. Indicates the minimum radius of the circle that contains.
  • the sphericity of 50 particles randomly selected from the image of the particles obtained by SEM observation was determined by the above method, and the average value thereof was defined as the sphericity.
  • a polishing liquid (content of pulverized abrasive: 0.25% by mass) having a total amount of 1000 g and a pH of 6.0 (25 ° C.).
  • the ceria particles contained in the polishing liquid had an average primary particle size of 50 nm and an average secondary particle size of 145 nm.
  • the average primary particle size and average secondary particle size of the ceria particles contained in the polishing liquid were determined in the same manner as the average primary particle size and average secondary particle size of the ceria particles contained in the slurry, respectively.
  • the pH of the polishing liquid was measured with a pH meter (Model PH81 (trade name) manufactured by Yokogawa Electric Corporation).
  • a blanket wafer on which no pattern was formed was used.
  • a silicon (Si) substrate having a silicon oxide film formed by a plasma TEOS method and a silicon (Si) substrate having a silicon nitride film formed by a low pressure CVD method were used.
  • the wafer was polished by a polishing apparatus (F-REX-300 manufactured by Ebara Corporation).
  • the wafer was set in a holder to which a substrate mounting suction pad was attached in a polishing apparatus.
  • the processing load is set to 210 gf / cm 2 (20.6 kPa), and the polishing platen and the wafer are rotated at 130 rpm for each time while the polishing liquid is dropped on the polishing pad at a rate of 250 ml / min.
  • the wafer was polished. After polishing, the wafer was thoroughly washed with pure water and dried.
  • the film thickness before and after polishing was measured using an optical interference type film thickness measuring apparatus to examine the polishing rate. The results are shown in Table 1.
  • Example 2 Slurry and polishing were carried out in the same manner as in Example 1 except that the processing time of the bead mill was changed as follows to pulverize the colloidal ceria until the average primary particle size and average secondary particle size shown in Table 1 were obtained.
  • a liquid was prepared. Using the prepared polishing liquid, the film to be polished was polished in the same manner as in Example 1, and the polishing rate was examined. The results are shown in Table 1. Processing time of bead mill Example 2: 50 minutes
  • Example 4 20 minutes
  • Example 3 A slurry and a polishing liquid were prepared in the same manner as in Example 1 except that a jet mill was used instead of the bead mill. Using the prepared polishing liquid, the film to be polished was polished in the same manner as in Example 1, and the polishing rate was examined. The results are shown in Table 1.
  • Example 3 A polishing liquid was prepared in the same manner as in Example 1 except that a slurry containing colloidal ceria having the average primary particle size and average secondary particle size shown in Table 1 and water was prepared without pulverizing the colloidal ceria. . Using the prepared polishing liquid, the film to be polished was polished in the same manner as in Example 1, and the polishing rate was examined. The results are shown in Table 1.
  • the polishing liquid obtained by subjecting colloidal ceria to the grinding treatment is the same as the polishing liquid obtained without performing the grinding treatment. It can be seen that the polishing rate is higher than that.

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Abstract

Un mode de réalisation de la présente invention est un procédé de production d'une suspension contenant des particules d'oxyde de cérium et de l'eau. Ce procédé de production d'une suspension comprend une étape de pulvérisation dans laquelle des particules d'oxyde de cérium sont obtenues par pulvérisation d'oxyde de cérium colloïdal dispersé dans de l'eau. Dans l'étape de pulvérisation, l'oxyde de cérium colloïdal est pulvérisé de telle sorte que le rapport du diamètre moyen de particule primaire des particules d'oxyde de cérium au diamètre de particule primaire moyen de l'oxyde de cérium colloïdal est inférieur à 0,8.
PCT/JP2016/085589 2016-11-30 2016-11-30 Suspension, liquide de polissage, procédé de production de ladite suspension, procédé de production dudit liquide de polissage, et procédé de polissage de substrat WO2018100686A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5012026B2 (ja) * 2004-11-08 2012-08-29 旭硝子株式会社 ＣｅＯ２微粒子の製造方法
JP5385306B2 (ja) * 2008-02-12 2014-01-08 サン−ゴバン セラミックス アンド プラスティクス，インコーポレイティド セリア材料およびセリア材料を形成する方法
JP5516396B2 (ja) * 2008-10-01 2014-06-11 旭硝子株式会社 研磨スラリー、その製造方法、研磨方法および磁気ディスク用ガラス基板の製造方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5012026B2 (ja) * 2004-11-08 2012-08-29 旭硝子株式会社 ＣｅＯ２微粒子の製造方法
JP5385306B2 (ja) * 2008-02-12 2014-01-08 サン−ゴバン セラミックス アンド プラスティクス，インコーポレイティド セリア材料およびセリア材料を形成する方法
JP5516396B2 (ja) * 2008-10-01 2014-06-11 旭硝子株式会社 研磨スラリー、その製造方法、研磨方法および磁気ディスク用ガラス基板の製造方法

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