JP2019165071A - Structure and method of manufacturing the same - Google Patents

Abstract

To provide a structure used for an electronic component capable of obtaining the electronic component with high yield.SOLUTION: A structure 100 includes: a substrate 10 having a plurality of convex portions and concave portions on a surface thereof; stoppers 20 disposed on the convex portions of the substrate 10; and insulating portions 30 disposed in concave portions of the substrate 10. The stoppers 20 include polysilicon. The stopper 20 and the insulating portions 30 are exposed on the surface of the structure 100. In the surface of the structure 100, surfaces of the stoppers 20 disposed on at least one of the convex portions have no dent defect.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a structure and a manufacturing method thereof.

  In recent years, research and development of processing techniques for increasing the density and miniaturization of electronic components have been promoted. One of the processing techniques, CMP (Chemical Mechanical Polishing), is a process for planarizing an interlayer insulating film and shallow trench isolation (shallow trench isolation) in the manufacturing process of electronic components. (Hereinafter referred to as “STI”), a plug formation process, a buried metal wiring formation process (damascene process), and the like. In the planarization process using CMP technology (hereinafter referred to as “CMP process”), the surface to be polished is generally supplied while supplying a polishing liquid between a polishing pad (polishing cloth) and the surface to be polished of the object to be polished. This is done by polishing. As a polishing liquid for CMP (hereinafter referred to as “CMP polishing liquid”), a ceria-based polishing liquid (for example, Patent Document 1 below) containing cerium oxide (ceria) particles as abrasive grains is known.

Japanese Patent Laid-Open No. 10-106994

  In the CMP process, the insulating portion may be selectively polished using a stopper. For example, an object to be polished comprising a substrate having a plurality of convex portions and concave portions on the surface, a stopper disposed on the convex portion of the substrate, and an insulating portion disposed on the concave portion of the substrate and disposed on the stopper. By polishing the insulating portion until the stopper is exposed, the insulating portion using the stopper can be selectively polished.

  In the technique of selectively polishing the insulating part using a stopper, the polishing rate ratio of the insulating material to the stopper material (polishing selectivity) is suppressed while suppressing the polishing rate of the stopper material in order to increase the density and miniaturization of electronic components. : Polishing rate of insulating material / polishing rate of stopper material) is required to be increased. However, even when a polishing liquid capable of obtaining a high polishing rate ratio is used, a dent defect may occur in the stopper after the CMP process (see FIG. 1). Since the stopper is also used as a conductive part that constitutes the gate electrode of the transistor or the like, if a dent defect occurs in the stopper, it greatly affects the reliability of the electronic component, so that the yield of electronic components (manufacturing yield) is large. Influence.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a structure that can be used for an electronic component and that can obtain the electronic component with a high yield, and a method for manufacturing the structure.

  The structure according to the present invention includes a substrate having a plurality of convex portions and concave portions on the surface, a stopper disposed on the convex portion of the substrate, and an insulating portion disposed on the concave portion of the substrate. A structure, wherein the stopper includes polysilicon, the stopper and the insulating portion are exposed on a surface of the structure, and are disposed on at least one of the convex portions on the surface of the structure. The surface of the stopper thus formed has no dent defect.

  The structure manufacturing method according to the present invention includes a substrate having a plurality of convex portions and concave portions on the surface, a stopper disposed on the convex portion of the substrate, and the stopper disposed on the concave portion of the substrate. A structure having an exposed surface of the stopper and the insulating portion is obtained by polishing and removing the insulating portion of the object to be polished including the insulating portion disposed on the surface until the stopper is exposed. The stopper includes polysilicon, and the surface of the stopper disposed on at least one of the convex portions has no dent defect on the surface of the structure.

  A “dent defect” is different from a polishing flaw and is difficult to detect visually. For example, when observed using an optical microscope, a circular or circular defect as shown in FIG. It shows a shape having a series of defects, for example, a width of 0.5 μm or more and a depth of 100 nm or less. “The surface of the stopper does not have a dent defect” means that the surface of the stopper after polishing is set with a 20 × objective lens using an optical microscope (for example, product name: DSX-510, manufactured by Olympus Corporation). The average value (average value of 5 images) of the number of concave defects (unit: piece / field of view) in five images (field range: 700 μm × 700 μm) obtained by photographing the central portion in FIG. (See FIG. 2).

  In the structure according to the present invention and the structure obtained by the method for manufacturing a structure according to the present invention, the surface of the stopper disposed on at least one of the convex portions has a dent defect on the surface of the structure. No. By manufacturing an electronic component using such a structure, the electronic component can be obtained with a high yield.

  ADVANTAGE OF THE INVENTION According to this invention, it is a structure used for an electronic component, Comprising: The structure which can obtain an electronic component with a sufficient yield, and its manufacturing method can be provided.

FIG. 1 is a diagram illustrating an example of a state in which the surface of the stopper has a dent defect. FIG. 2 is a diagram illustrating an example of a state in which the surface of the stopper does not have a dent defect. FIG. 3 is a schematic cross-sectional view illustrating an example of a structure. FIG. 4 is a schematic cross-sectional view for explaining an example of a method for manufacturing a structure.

  Hereinafter, embodiments of the present invention will be described.

<Structure and manufacturing method thereof>
FIG. 3 is a schematic cross-sectional view showing an example of a structure according to the present embodiment. 3 includes a substrate 10 having a plurality of convex portions (active portions) and concave portions (trench portions) on the surface, a stopper 20 disposed on the convex portions of the substrate 10, and concave portions of the substrate 10. And an insulating part 30 arranged. The convex portions and concave portions of the substrate 10 constitute an uneven pattern. The stopper 20 includes polysilicon. The insulating part 30 is arranged so as to fill the concave part of the concave-convex pattern of the substrate 10. The stopper 20 and the insulating part 30 are exposed on the surface of the structure 100.

  On the surface of the structure 100 (the surface on which the stopper 20 and the insulating portion 30 are exposed), the surface of the stopper 20 disposed on at least one of the plurality of convex portions does not have a dent defect. By using the structure 100 including the stopper 20 having a surface not having a dent defect as the structure used for the electronic component, the electronic component can be obtained with a high yield.

  The structure 100 can be used for manufacturing various electronic components. Electronic components include: semiconductor elements; optical glasses such as photomasks, lenses, and prisms; inorganic conductive films such as ITO; optical integrated circuits composed of glass and crystalline materials; optical switching elements; optical waveguides; Examples include optical single crystals such as scintillators; solid laser single crystals; sapphire substrates for blue laser LEDs; semiconductor single crystals such as SiC, GaP and GaAs; glass substrates for magnetic disks; magnetic heads and the like. By using the structure body 100, high integration can be achieved and excellent characteristics can be secured.

  The structure 100 only needs to have at least one stopper 20 having a surface that does not have a dent defect. For example, the structure 100 may be a mode in which the surfaces of the plurality of stoppers 20 disposed on the plurality of convex portions do not have a dent defect, and all the structures disposed on the plurality of convex portions may be provided. The aspect which the surface of the stopper 20 does not have a dent defect may be sufficient.

  As the substrate 10, for example, an insulating part is formed on a semiconductor substrate such as a substrate related to semiconductor element manufacturing (for example, a semiconductor substrate at a stage where a circuit element and a wiring pattern are formed, a semiconductor substrate at a stage where a circuit element is formed). Substrate). In addition, although the uneven | corrugated pattern is formed in the surface of the board | substrate shown in FIG. 3, you may use the board | substrate with which the uneven | corrugated pattern is not formed in the surface.

  The shape of the stopper 20 is not particularly limited, and is, for example, a film shape (a stopper film such as a polysilicon film).

  Examples of the insulating material constituting the insulating portion 30 include inorganic insulating materials and organic insulating materials. Examples of inorganic insulating materials include silicon-based insulating materials. Examples of the silicon-based insulating material include silica-based materials such as silicon oxide, carbon-containing silicon oxide, fluorosilicate glass, organosilicate glass, and hydrogenated silsesquioxane; silicon carbide; silicon nitride (silicon nitride) and the like. Examples of the organic insulating material include a wholly aromatic low dielectric constant insulating material. The insulating material is preferably silicon oxide. The insulating material may be doped with an element such as phosphorus or boron. The shape of the insulating portion 30 is not particularly limited, and is, for example, a film shape (insulating film).

  FIG. 4 is a schematic cross-sectional view for explaining an example of the structure manufacturing method according to the present embodiment, and shows an object to be polished (substrate) 200 for obtaining the structure 100 shown in FIG. 4 includes a substrate 10 having a plurality of convex portions and concave portions on the surface, a stopper 20 disposed on the convex portions of the substrate 10, a concave portion of the substrate 10, and the substrate 10 and And an insulating part 30 disposed on the stopper 20. The surface of the insulating part 30 of the object to be polished 200 has an uneven pattern similar to the uneven pattern on the surface of the substrate 10.

  As the insulating portion 30 of the object to be polished 200, an insulating film formed on a semiconductor substrate; an inorganic insulating material such as silicon oxide, glass, silicon nitride formed on a wiring board having a predetermined wiring; Al, Cu, Ti, A material mainly containing TiN, W, Ta, TaN or the like can be used. Polishing of the insulating portion 30 of the object to be polished 200 may be performed by a planarization process of an interlayer insulating film, a BPSG film, or the like; a shallow trench isolation (STI) formation process, or the like.

  Examples of the object to be polished 200 include individual semiconductors such as diodes, transistors, compound semiconductors, thermistors, varistors, and thyristors; DRAM (dynamic random access memory), SRAM (static random access memory), EPROM ( Memory elements such as erasable programmable read only memory (ROM), mask ROM (mask read only memory), EEPROM (electrically erasable programmable read only memory), flash memory; microprocessor, DSP, A theoretical circuit element such as ASIC; an integrated circuit element such as a compound semiconductor typified by MMIC (monolithic microwave integrated circuit); a hybrid integrated circuit (hybrid IC); Ord, and a substrate having a like photoelectric conversion element such as a charge coupled device.

  The manufacturing method of the structure 100 (polishing method of the object to be polished 200) includes removing the insulating part 30 of the object to be polished 200 by polishing (CMP) until the stopper 20 is exposed, thereby removing the stopper 20 and the insulating part 30. A polishing step of obtaining a structure 100 having a surface where the surface is exposed. In the polishing step, the insulating portion 30 of the object to be polished 200 can be polished using a polishing liquid. In the polishing step, a polishing liquid obtained by mixing a slurry and an additive liquid in a polishing liquid set described later may be used. In the polishing step, the insulating material (insulating portion) can be selectively (preferentially) polished with respect to the stopper material (stopper). For example, silicon oxide can be selectively (preferentially) polished with respect to polysilicon. The polishing step may be a step of polishing silicon oxide using polysilicon as a stopper material.

  The polishing step can be performed using, for example, a general polishing apparatus having a holder capable of holding the object to be polished and a polishing surface plate to which a polishing pad can be attached. The polishing step is performed, for example, according to the following procedure. First, the object to be polished 200 is placed on the polishing pad so that the surface of the object to be polished 200 (the surface of the insulating portion 30 and the surface formed of an insulating material) faces the polishing pad. Next, in a state where the surface of the object to be polished 200 is pressed against the polishing pad of the polishing surface plate, a polishing liquid is supplied between the polishing pad and the insulating portion 30 so that the object to be polished 200 and the polishing surface plate are relatively moved. The surface of the object 200 is polished by moving. The insulating portion 30 is polished and removed until the stopper 20 is exposed. Thereby, the unevenness | corrugation of the surface of the to-be-polished body 200 is eliminated, and the structure 100 which has a smooth surface can be obtained.

  In the polishing step, it is preferable to end the polishing when all of the surfaces of the stopper 20 that are parallel to the surface of the substrate 10 are exposed. In the polishing step, a part of the stopper 20 may be polished together with the insulating portion 30, but it is preferable not to polish the stopper 20 from the viewpoint of preventing the stopper 20 from having a dent defect.

  Examples of the polishing apparatus include a polishing apparatus manufactured by APPLIED MATERIALS (trade name: Mirra-3400, Reflexion LK), a polishing apparatus manufactured by Ebara Corporation (trade name: F-REX300), and the like.

  As the polishing pad, a general nonwoven fabric, foam, non-foam, or the like can be used. The material of the polishing pad is polyurethane, acrylic resin, polyester, acrylic-ester copolymer, polytetrafluoroethylene, polypropylene, polyethylene, poly-4-methylpentene, cellulose, cellulose ester, polyamide (for example, nylon (trade name)) And aramid), polyimide, polyimide amide, polysiloxane copolymer, oxirane compound, phenol resin, polystyrene, polycarbonate, epoxy resin and the like. The material of the polishing pad is preferably at least one selected from the group consisting of foamed polyurethane and non-foamed polyurethane, particularly from the viewpoint of easily obtaining an excellent polishing rate and surface flatness. The polishing pad may be grooved so that the polishing liquid accumulates.

Polishing conditions are not particularly limited. The rotation speed of the polishing platen is preferably 200 min ⁻¹ (rpm) or less so that the object 200 is not popped out of the polishing platen. The polishing pressure (working load) applied to the object to be polished 200 is preferably 100 kPa or less from the viewpoint of easily suppressing the occurrence of polishing scratches on the polished surface. In the polishing step, it is preferable to continuously supply the polishing liquid to the polishing pad with a pump or the like while polishing. The supply amount of the polishing liquid is not limited, but it is preferable that the surface of the polishing pad is always covered with the polishing liquid.

  Finally, the structure after polishing is thoroughly washed in running water to remove particles adhering to the structure. For cleaning, dilute hydrofluoric acid or ammonia water may be used in addition to pure water, and a brush may be used to improve cleaning efficiency. In addition, after washing, it is preferable to dry the structure after removing water droplets adhering to the structure using spin drying or the like.

  The manufacturing method of the structure 100 may include a to-be-polished body preparation step for preparing the to-be-polished body 200 before the polishing step. In the object preparation step, the object to be polished may be obtained by forming the insulating portion 30 on the one surface of the substrate 10 provided with the stopper 20 on one surface. For example, after preparing a laminate having the substrate 10 and the stopper 20 formed on the convex portion of the substrate 10, an insulating material constituting the insulating portion 30 is made of the substrate 10 so as to fill the concave portion on the surface of the substrate 10. Further, the object to be polished may be obtained by depositing on the stopper 20. Examples of the method for forming the insulating portion 30 include a low pressure CVD method, a plasma CVD method, and a coating method.

When the insulating part 30 is a silicon oxide film made of silicon oxide, the silicon oxide film is formed by low-pressure CVD using monosilane (SiH ₄ ) as the Si source and oxygen (O ₂ ) as the oxygen source. be able to. A silicon oxide film can be obtained by performing this SiH ₄ —O ₂ -based oxidation reaction at a low temperature of 400 ° C. or lower. A silicon oxide film obtained by CVD can be heat-treated at a temperature of 1000 ° C. or lower. In the case where the silicon oxide film is doped with phosphorus in order to planarize the surface by high-temperature reflow, a SiH ₄ —O ₂ —PH ₃ -based reactive gas can be preferably used.

The plasma CVD method has an advantage that a chemical reaction requiring a high temperature can be performed at a low temperature under normal thermal equilibrium. There are two methods for generating plasma, a capacitive coupling type and an inductive coupling type. The reaction gases, SiH ₄ as an Si source, _SiH 4 -N ₂ O-containing gas using _{N 2} O as an oxygen source, TEOS-O-based gas using tetraethoxysilane (TEOS) as 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.

When the insulating part 30 is a silicon nitride film made of silicon nitride, the formation of the silicon nitride film by the low pressure CVD method uses dichlorosilane (SiH ₂ Cl ₂ ) as the Si source and ammonia (NH ₃ ) as the nitrogen source. Can be done. A silicon nitride film can be obtained by performing this SiH ₂ Cl ₂ —NH ₃ -based oxidation reaction at a high temperature such as 900 ° C. Examples of the reactive gas in the formation of the silicon nitride film by the plasma CVD method 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.

In the workpiece preparation step, the stopper 20 may be formed on the substrate 10 by the CVD method. The formation of the polysilicon film by the CVD method can be performed at a substrate temperature of 600 to 1000 ° C. using SiH ₄ as a Si source, for example.

<Polishing liquid>
The structure according to the present embodiment can be obtained, for example, by polishing and removing the insulating portion of the object to be polished until the stopper is exposed using a polishing liquid. Hereinafter, an example of the polishing liquid according to the present embodiment will be described.

The polishing liquid according to the present embodiment includes a substrate having a plurality of convex portions and concave portions on the surface, a stopper disposed on the convex portion of the substrate, and an insulating portion disposed on the concave portion of the substrate and disposed on the stopper. A polishing liquid (CMP) used to obtain a structure having a surface where the stopper and the insulating portion are exposed by removing the insulating portion of the object to be polished by polishing (CMP) until the stopper is exposed. Polishing liquid). The polishing liquid according to this embodiment contains, for example, abrasive grains containing cerium, a nonionic water-soluble compound A, and water, and the content of the basic pH adjuster is the total mass of the polishing liquid. Is less than 1.3 × 10 ⁻² mol / kg. The polishing liquid according to the present embodiment may contain a basic pH adjuster or may not contain a basic pH adjuster. When the polishing liquid according to this embodiment does not contain a basic pH adjusting agent, the content of the basic pH adjusting agent may be 0 mol / kg.

  According to such a polishing liquid, it is possible to achieve both an excellent polishing rate ratio of the insulating material to the stopper material and suppression of the occurrence of the dent defect of the stopper.

  Hereinafter, the components of the polishing liquid according to this embodiment will be described in detail.

(Abrasive grains)
The abrasive grains contain cerium from the viewpoint of obtaining a polishing action on an insulating material (silicon oxide, carbon-containing silicon oxide, etc.). In the present specification, “abrasive grains” means particles contained in the polishing liquid or aggregates thereof and are also referred to as “abrasive particles”. Abrasive grains are generally solid particles. In polishing using abrasive grains, it is considered that the object to be removed is removed by the mechanical action of the abrasive grains and the chemical action of the abrasive grains (mainly the surface of the abrasive grains). The polishing mechanism using grains is not limited to this.

  Constituents of abrasive grains containing cerium include cerium oxide (ceria), cerium hydroxide, ammonium cerium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromate, cerium bromide, cerium chloride, cerium oxalate, nitric acid Examples include cerium, cerium carbonate, and cerium-modified products. In other words, the polishing liquid according to the present embodiment may include particles containing the above-described components (cerium oxide, cerium hydroxide, etc.) as abrasive grains containing cerium. Examples of the particles containing a modified cerium include those obtained by modifying the surface of particles containing cerium oxide, cerium hydroxide, etc. with an alkyl group, and composite particles in which other particles are attached to the surface of particles containing cerium. . Abrasive grains preferably contain at least one selected from the group consisting of cerium oxide and cerium hydroxide, from the viewpoint of obtaining an effect such that the polishing rate of the insulating material is stable and the amount of dishing is easily reduced. More preferably, it contains cerium oxide.

  The particles containing cerium oxide (hereinafter referred to as “cerium oxide particles”) are not particularly limited, and known particles can be used. Preferred cerium oxide particles are particles obtained by oxidizing cerium salts such as carbonates, nitrates, sulfates, and oxalates. Examples of the oxidation method include a firing method in which the cerium salt is fired at about 600 to 900 ° C., and a chemical oxidation method in which the cerium salt is oxidized using an oxidizing agent such as hydrogen peroxide. As a method for producing the cerium oxide particles, a firing method is preferable from the viewpoint of easily obtaining a high polishing rate of the insulating material, and a chemical oxidation method is preferable from the viewpoint that polishing scratches are unlikely to occur on the surface after polishing.

  When the cerium oxide particles are used, the larger the crystallite diameter (crystallite diameter) of the cerium oxide particles and the smaller the crystal distortion (that is, the higher the crystallinity), the faster the polishing is possible. Abrasion scratches are likely to enter the polished surface. From such a viewpoint, preferable cerium oxide particles include particles composed of two or more crystallites and having a crystal grain boundary. Among these, particles having a crystallite diameter of 5 to 300 nm are more preferable. Another preferable cerium oxide particle includes colloidal ceria particles having a crystallite diameter of 5 to 300 nm (for example, colloidal ceria manufactured by Rhodia).

  The average grain size of the abrasive grains is preferably 10 nm or more, more preferably 20 nm or more, and further preferably 50 nm or more from the viewpoint of obtaining a better polishing rate for the insulating material. The average grain size of the abrasive grains is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less, from the viewpoint that the surface to be polished is less likely to be scratched and the occurrence of dent defects is easily suppressed. . From these viewpoints, the average particle size of the abrasive grains is preferably 10 to 500 nm, more preferably 20 to 400 nm, and still more preferably 50 to 300 nm.

  Here, the average particle size of the abrasive grains is measured as a refractive index of 1.93 and an absorption of 0 using a laser diffraction particle size distribution analyzer (for example, product name: LA-920, manufactured by Horiba, Ltd.). The value of D50 (median diameter of volume distribution, cumulative median value) of the measurement sample. For the measurement of the average particle diameter, a sample having an appropriate content (for example, a content at which the measurement transmittance (H) with respect to a He—Ne laser is 60 to 70%) is used. In addition, when the polishing liquid containing abrasive grains is stored separately in a cerium slurry in which abrasive grains are dispersed in water and an additive liquid, the cerium slurry can be diluted to an appropriate content and measured. it can.

  The abrasive may contain components other than cerium. Examples of the components other than cerium include at least one selected from the group consisting of silica, alumina, zirconia, manganese oxide, magnesium oxide, titania, germania, resin, diamond, silicon carbide, cubic boron nitride, and modified products thereof. Can be mentioned. In other words, the polishing liquid according to this embodiment may contain particles containing the above components (for example, silica, alumina, etc.) as abrasive grains. Colloidal alumina can also be used as the particles containing alumina. Particles containing the above modified product include particles containing silica, alumina, zirconia, titania, germania, manganese oxide, magnesium oxide, etc., modified with alkyl groups, and other particles attached to the surface of one particle. Composite particles and the like. An abrasive grain can be used individually by 1 type or in combination of 2 or more types.

  The abrasive grains may be obtained by any manufacturing method. For example, oxide production methods include solid phase methods such as firing; liquid phase methods such as precipitation methods, sol-gel methods, and hydrothermal synthesis methods; gas phase methods such as sputtering methods, laser methods, and thermal plasma methods. Can be used.

  When the abrasive grains are aggregated, the aggregated abrasive grains may be mechanically pulverized. As the pulverization method, for example, a dry pulverization method using a jet mill or the like, and a wet pulverization method using a planetary bead mill or the like are preferable. For the jet mill, for example, a method described in “Chemical Engineering Journal”, Vol. 6, No. 5, (1980), pages 527 to 532 can be applied.

  When the abrasive grains are applied to the polishing liquid, the polishing liquid is preferably obtained by dispersing the abrasive grains in water which is a main dispersion medium. Examples of the dispersion method include a method using a homogenizer, an ultrasonic disperser, a wet ball mill, and the like in addition to a dispersion treatment using a normal stirrer. Regarding the dispersion method and the particle size control method, for example, the method described in Chapter 3 “Latest Development Trends and Selection Criteria of Various Dispersers” in “Dispersion Technology Complete Collection” [Information Organization, July 2005] Can be used. Moreover, the dispersibility of an abrasive grain can also be improved by lowering the electrical conductivity of a dispersion containing abrasive grains (for example, 500 mS / m or less). As a method of lowering the electrical conductivity of the dispersion, solid-liquid separation is performed by centrifugation to separate the abrasive grains from the dispersion medium, the supernatant liquid (dispersion medium) is discarded, and a dispersion medium with low electrical conductivity is added. Examples of the method of redispersing include ultrafiltration, a method using an ion exchange resin, and the like.

  The abrasive grains dispersed by the above method may be further finely divided. Examples of the fine particle method include a sedimentation classification method (a method in which abrasive grains are centrifuged with a centrifuge and then forcedly settled, and only the supernatant liquid is taken out). In addition, a high-pressure homogenizer that causes the abrasive grains in the dispersion medium to collide with each other at a high pressure may be used.

  The content of cerium in the abrasive grains is preferably 50% by mass or more, more preferably 60% by mass or more, based on the total mass of the abrasive grains, from the viewpoint that the effect of improving the polishing rate of the insulating material is easily obtained. Yes, more preferably 70% by mass or more, particularly preferably 80% by mass or more, and very preferably 90% by mass or more. The content of cerium in the abrasive grains may be 100% by mass based on the total mass of the abrasive grains. The content is the content of cerium in the entire abrasive grains, but the content of cerium in one abrasive grain may be in the above range.

  The content of abrasive grains containing cerium (for example, cerium oxide particles) is from the viewpoint of suppressing the agglomeration of the abrasive grains, making it easier to suppress the occurrence of dent defects, and making it easier to suppress the occurrence of dishing, and the like. Based on the total mass of the polishing liquid, it is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, particularly preferably 3% by mass or less, Preferably it is 1 mass% or less. The content of abrasive grains containing cerium (for example, cerium oxide particles) is preferably 0.01% by mass or more based on the total mass of the polishing liquid from the viewpoint of easily obtaining an effect of improving the polishing rate of the insulating material. More preferably, it is 0.1 mass% or more, More preferably, it is 0.2 mass% or more. From these viewpoints, the content of abrasive grains (for example, cerium oxide particles) is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, based on the total mass of the polishing liquid. Yes, more preferably 0.2 to 5% by mass, particularly preferably 0.2 to 3% by mass, and most preferably 0.2 to 1% by mass.

  The content of the abrasive grains is preferably 20% by mass or less, more preferably 10% by mass, based on the total mass of the polishing liquid, from the viewpoint of suppressing the aggregation of the abrasive grains and easily suppressing the occurrence of dent defects. Or less, more preferably 5% by mass or less, particularly preferably 3% by mass or less, and most preferably 1% by mass or less. The content of the abrasive grains is preferably 0.01% by mass or more, more preferably 0.1% by mass, based on the total mass of the polishing liquid, from the viewpoint that an effect of improving the polishing rate of the insulating material is easily obtained. It is above, More preferably, it is 0.2 mass% or more. From these viewpoints, the content of the abrasive grains is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, and still more preferably 0, based on the total mass of the polishing liquid. .2 to 5% by mass, particularly preferably 0.2 to 3% by mass, and most preferably 0.2 to 1% by mass.

(Water-soluble compound A)
The water-soluble compound A is a nonionic water-soluble compound. The water-soluble compound A contributes to suppressing the polishing of the stopper. This is presumably because the nonionic water-soluble compound has an affinity for the stopper material rather than the insulating material, and is more likely to adhere to the surface of the stopper than the surface of the insulating portion. That is, it is assumed that the polishing of the stopper is suppressed by the water-soluble compound A adhering to the surface of the stopper when the polishing of the insulating portion proceeds and the stopper is exposed in the CMP process. In the present specification, the “water-soluble compound” is defined as a compound that dissolves 0.1 g or more in 100 g of water at 25 ° C.

  As the water-soluble compound A, a wide variety of water-soluble compounds used as polishing inhibitors for stopper materials can be used. Examples of the water-soluble compound A include a compound having a (poly) oxyalkylene chain (for example, a (poly) oxyethylene adduct of a polyalkylene glycol, a polyoxyalkylene derivative and an acetylene-based diol); an acetylene-based diol (for example, 2,4 , 7,9-tetramethyl-5-decyne-4,7-diol); polyglycerol; vinyl alcohol polymer (excluding compounds corresponding to compounds having a (poly) oxyalkylene chain); acrylamide, methacryl A water-soluble polymer compound having an N-mono-substituted or N, N-di-substituted skeleton of any compound selected from the group consisting of amides and α-substituted thereof (for example, N-mono substituted and Polymers having at least one N, N-disubstituted product as a monomer) are preferred. These can be used singly or in combination of two or more.

  Examples of the polyalkylene glycol include polyethylene glycol and polypropylene glycol.

  Examples of the polyoxyalkylene derivative include a compound obtained by introducing a substituent into polyalkylene glycol, a compound obtained by adding polyalkylene oxide to an organic compound, and the like. Examples of the substituent include alkyl ether, alkylphenyl ether, phenyl ether, styrenated phenyl ether, alkylamine, fatty acid ester, glycol ester, polyglyceryl ether, diglyceryl ether, sugar ether, sugar ester and the like.

  Examples of the polyoxyalkylene derivative include polyoxyethylene styrenated phenyl ether (for example, Neugen (registered trademark) EA series manufactured by Daiichi Kogyo Seiyaku Co., Ltd.); polyoxyethylene alkyl ether (for example, Kao Corporation, Emulgen) (Registered trademark) series); polyoxyethylene alkyl phenyl ether (for example, Daimaru Kogyo Seiyaku Co., Ltd., Emulgit (registered trademark) series); polyoxyethylene sorbitan fatty acid ester (for example, Daiichi Kogyo Seiyaku Co., Ltd., Sorgen) (Registered trademark) TW series); polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyethylene glycol monooleate, polyoxyethylene hydrogenated castor oil, etc. Oxyethylene fatty acid esters (for example, Emanon (registered trademark) series manufactured by Kao Corporation); polyoxyethylene alkylamine (for example, Amiradin (registered trademark) D manufactured by Daiichi Kogyo Seiyaku Co., Ltd.); polyoxypropylene sorbitol (for example, Manufactured by NOF Corporation, Uniol (registered trademark) HS-1600D); polyoxyethylene diglyceryl ether (for example, SC-E series manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.), polyoxypropylene diglyceryl ether (for example, Sakamoto Yakuhin) Polyoxyalkylene diglyceryl ether such as Kogyo Co., Ltd. (SY-DP series); polyoxyalkylene polyglyceryl ether such as polyoxyethylene polyglyceryl ether and polyoxypropylene polyglyceryl ether; Compounds obtained by adding an de (for example, Air Products Japan, Inc., Surfynol (registered trademark) 465; Nippon emulsifier Co., Ltd., TMP series) and the like are preferable.

  As the (poly) oxyethylene adduct of acetylene-based diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol-dipolyoxyethylene ether, 2,4,7,9-tetra And methyl-5-decyne-4,7-diol-monopolyoxyethylene ether. From the viewpoints of both water solubility and surface tension reduction, 2,4,7,9-tetramethyl-5-decyne-4,7-diol-dipolyoxyethylene ether is particularly preferable.

Since vinyl alcohol tends not to exist as a stable compound by itself, a vinyl alcohol polymer is generally obtained by polymerizing a vinyl carboxylate monomer such as a vinyl acetate monomer to obtain a vinyl polycarboxylate. Obtained by saponification (hydrolysis). Therefore, for example, a vinyl alcohol polymer obtained using a vinyl acetate monomer as a raw material has an OCOCH ₃ group and a hydrolyzed hydroxyl group (OH group) in the molecule, and is generated by hydrolysis. The proportion of the hydroxyl group is defined as the degree of saponification. That is, a vinyl alcohol polymer whose saponification degree is not 100% has a structure substantially like a copolymer of a vinyl carboxylate monomer and vinyl alcohol. In addition, the vinyl alcohol polymer is obtained by copolymerizing a vinyl carboxylate monomer such as vinyl acetate monomer and other vinyl group-containing monomers (for example, ethylene, propylene, styrene, vinyl chloride, etc.) It may be a saponified part or all of the derived part. Specific examples of such a vinyl alcohol polymer include PVA-403 manufactured by Kuraray Co., Ltd., JC-25 manufactured by Nihon Acetate / Poval Co., Ltd. In this specification, these are collectively defined as “vinyl alcohol polymer”.

  The vinyl alcohol polymer is a vinyl alcohol homopolymer derivative (ie, a polymer having a saponification degree of 100%), a vinyl alcohol monomer and other vinyl group-containing monomers (eg, ethylene, propylene, styrene, vinyl chloride, vinyl acetate, etc. Or a derivative of a copolymer thereof. Examples of such a derivative include a compound in which at least a part of the hydroxyl group is substituted with an amino group, a carboxyl group, an ester group, or the like, a compound in which at least a part of the hydroxyl group is modified, and the like. Specifically, reactive polyvinyl alcohol (for example, GOHSEIMER (registered trademark) Z manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), cationized polyvinyl alcohol (for example, GOHSEIMER (registered trademark) manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) (Trademark) K), anionized polyvinyl alcohol (for example, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., GOCERAN (registered trademark) L, GOHSENAL (registered trademark) T), hydrophilic group-modified polyvinyl alcohol (for example, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) , Ecomatic (registered trademark)) and the like.

  The water-soluble polymer compound having an N-mono-substituted or N, N-di-substituted skeleton is a highly water-soluble polymer having a structural unit derived from an N-mono-substituted or N, N-di-substituted skeleton as a basic skeleton. It is a molecular compound. Examples of N-mono-substituted or N, N-di-substituted are N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-isopropylacrylamide, N-butylacrylamide, N-isobutylacrylamide, and N-tertiary. Butylacrylamide, N-heptylacrylamide, N-octylacrylamide, N-tertiaryoctylacrylamide, N-dodecylacrylamide, N-octadecylacrylamide, N-methylolacrylamide, N-acetylacrylamide, N-diacetoneacrylamide, N-methylmethacryl Amide, N-ethylmethacrylamide, N-propylmethacrylamide, N-isopropylmethacrylamide, N-butylmethacrylamide, N-isobutylmethacrylamide N-tertiarybutylmethacrylamide, N-heptylmethacrylamide, N-octylmethacrylamide, N-tertioctylmethacrylamide, N-dodecylmethacrylamide, N-octadecylmethacrylamide, N-methylolmethacrylamide, N-acetyl N-monosubstituted products such as methacrylamide, N-diacetone methacrylamide; N, N-dimethylacrylamide, N, N-diethylacrylamide, N, N-dipropylacrylamide, N, N-diisopropylacrylamide, N, N- Dibutylacrylamide, N, N-diisobutylacrylamide, N, N-ditertiarybutylacrylamide, N, N-diheptylacrylamide, N, N-dioctylacrylamide, N, N-ditertiaryoctylacrylic Amide, N, N-didodecylacrylamide, N, N-dioctadecylacrylamide, N, N-dimethylolacrylamide, N, N-diacetylacrylamide, N, N-diacetoneacrylamide, N, N-dimethylmethacrylamide, N , N-diethylmethacrylamide, N, N-dipropylmethacrylamide, N, N-diisopropylmethacrylamide, N, N-dibutylmethacrylamide, N, N-diisobutylmethacrylamide, N, N-ditertiarybutylmethacrylamide, N, N-diheptyl methacrylamide, N, N-dioctyl methacrylamide, N, N-ditertioctyl methacrylamide, N, N-didodecyl methacrylamide, N, N-dioctadecyl methacrylamide, N, N-di Methylol methacrylate Examples include N, N-disubstituted products such as luamide, N, N-diacetylmethacrylamide, N, N-diacetone methacrylamide, acryloylpiperidine, acryloylmorpholine, acryloylthiomorpholine, and acryloylpyrrolidine.

  As the water-soluble compound A, 2-hydroxyethyl methacrylate, alkyl alkanolamide, or the like may be used.

  The weight average molecular weight of the water-soluble compound A is preferably 200 or more, more preferably 500 or more, still more preferably 1000 or more, and particularly preferably 2000 or more. There exists a tendency for the effect which suppresses polishing of a stopper to become high, so that the weight average molecular weight of the water-soluble compound A is large. The weight average molecular weight of the water-soluble compound A is preferably 3 million or less, more preferably 1 million or less, still more preferably 50,000 or less, particularly preferably 20,000 or less, and extremely preferably 10,000 or less. If the weight average molecular weight of the water-soluble compound A becomes too large, the viscosity of the polishing liquid increases, and problems such as precipitation of abrasive grains may occur. From these viewpoints, the weight average molecular weight of the water-soluble compound A is preferably 2 to 3 million, more preferably 5 to 3 million, still more preferably 1000 to 1 million, and particularly preferably 2000 to 5 million. It is 10,000, very preferably 2000 to 20,000, and even more preferably 2000 to 10,000.

The weight average molecular weight can be measured by the following method and reading the value obtained as “Mw”.
{Measuring method}
Equipment used (detector): Hitachi, Ltd., “L-3300” differential refractometer for liquid chromatograph Pump: Hitachi, Ltd., “L-7100” for liquid chromatograph
Degas equipment: None Data processing: GPC integrator “D-2520” manufactured by Hitachi, Ltd.
Column: “Shodex Asahipak GF-710HQ” manufactured by Showa Denko KK, inner diameter 7.6 mm × 300 mm
Eluent: 50 mM Na ₂ HPO ₄ aqueous solution / acetonitrile = 90/10 (v / v)
Measurement temperature: 25 ° C
Flow rate: 0.6 mL / min (L represents liter. The same applies hereinafter)
Measurement time: 30 minutes Sample: Sample prepared by adjusting the concentration with a solution having the same composition as the eluent so as to have a resin concentration of 2% by mass, and filtering through a 0.45 μm polytetrafluoroethylene filter Injection amount: 0 .4 μL
Reference material: Polymer Laboratories, narrow molecular weight sodium polyacrylate

  The content of the water-soluble compound A is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.05% by mass or more, based on the total mass of the polishing liquid. It is. When the content of the water-soluble compound A is 0.005% by mass or more, it is easy to obtain a polishing suppressing effect on the stopper material (particularly polysilicon). The content of the water-soluble compound A is preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.3% by mass or less, based on the total mass of the polishing liquid. . When the content of the water-soluble compound A is 2% by mass or less, the polishing rate of the insulating material (particularly silicon oxide) is likely to be sufficient, and the fluidity is not easily lowered due to gelation of the polishing liquid. From these viewpoints, the content of the water-soluble compound A is preferably 0.005 to 2% by mass, more preferably 0.005 to 1% by mass, and still more preferably based on the total mass of the polishing liquid. Is 0.005 to 0.3% by mass, particularly preferably 0.01 to 0.3% by mass, and most preferably 0.05 to 0.3% by mass.

(Polymer Compound B)
The polishing liquid according to the present embodiment can contain a polymer compound B having at least one selected from the group consisting of a carboxylic acid group and a carboxylic acid group, if necessary. The polymer compound B contributes to reducing the dishing amount in the insulating portion. The high molecular compound B may be used individually by 1 type, and may use 2 or more types together. In addition, the high molecular compound B can also be used for dispersion | distribution of an abrasive grain.

  The number of carboxylic acid groups and carboxylic acid groups in the polymer compound B is not particularly limited. The polymer compound B may be a monocarboxylic acid or a salt thereof, and may be a polycarboxylic acid or a salt thereof. The polymer compound B may be, for example, a special polycarboxylic acid type polymer compound (such as DEMOL (registered trademark) EP manufactured by Kao Corporation).

  As the polymer compound B, 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 (hereinafter referred to as “(meth) acrylic acid polymer”). Are collectively referred to as “.” The monomer may contain other monomers copolymerizable with acrylic acid or methacrylic acid (excluding acrylic acid and methacrylic acid).

  As the high molecular compound B, a homopolymer of acrylic acid (polyacrylic acid), a homopolymer of methacrylic acid (polymethacrylic acid), a copolymer of acrylic acid and methacrylic acid, acrylic acid or methacrylic acid and other It may be at least one selected from the group consisting of copolymers with monomers, copolymers of acrylic acid and methacrylic acid with other monomers, and salts thereof. Among them, the (meth) acrylic acid polymer is selected from the group consisting of a homopolymer of acrylic acid (polyacrylic acid) and a salt thereof from the viewpoint of good adsorption to the material to be polished (insulating material, etc.). At least one of these is preferred. Examples of the polymer salt (polymer having a carboxylate group) include ammonium salts. Examples of the ammonium salt include ammonium polyacrylate. In addition, a (meth) acrylic-acid type polymer may be used individually by 1 type, and may use 2 or more types together.

  Other monomers (other monomers copolymerizable with acrylic acid or methacrylic acid) include, for example, crotonic acid, pentenoic acid, hexenoic acid, heptenoic acid, octenoic acid, nonenic acid, decenoic acid, undecenoic acid And unsaturated carboxylic acids such as dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid and heptadecenoic acid; and vinyl compounds such as ethylene, propylene and styrene.

  Although the weight average molecular weight of the high molecular compound B does not have a restriction | limiting in particular, Preferably it is 500-150,000, More preferably, it is 1000-80000. When the weight average molecular weight of the polymer compound B is 500 or more, it becomes easy to obtain a good polishing rate when polishing an insulating material (such as silicon oxide). When the weight average molecular weight of the polymer compound B is 150,000 or less, the storage stability of the polishing liquid is hardly lowered. The weight average molecular weight of the polymer compound B can be measured by the same method as that for the water-soluble compound A.

  The content of the polymer compound B in the polishing liquid is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and still more preferably 0.05, based on the total mass of the polishing liquid. It is at least mass%, particularly preferably at least 0.1 mass%. The content of the polymer compound B is preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, based on the total mass of the polishing liquid. Preferably it is 0.35 mass% or less, Very preferably it is 0.30 mass% or less, Very preferably it is 0.25 mass% or less, More preferably, it is 0.20 mass% or less. When the content of the polymer compound B is 0.001 to 2% by mass, the storage stability can be improved, and the dishing amount, wiring density dependency, etc. are reduced, and the surface flatness is improved. There is a tendency to be able to. That is, when the content of the polymer compound B is 0.001% by mass or more, the dishing amount can be reduced, and the surface flatness tends to be sufficiently secured. When the amount is 2% by mass or less, the storage stability of the abrasive grains is improved, so that the aggregation of the abrasive grains is difficult to occur, the occurrence of the dent defect is easily suppressed, the dishing amount is easily reduced, etc. There is a tendency to obtain the effect. From these viewpoints, the content of the polymer compound B is preferably 0.001 to 2% by mass, more preferably 0.01 to 1% by mass, and still more preferably 0.05 to 0.5% by mass. %, Particularly preferably 0.05 to 0.35% by mass, very preferably 0.05 to 0.25% by mass, and still more preferably 0.1 to 0.25% by mass.

(PH adjuster)
The polishing liquid according to the present embodiment can contain a pH adjuster (for example, a basic pH adjuster) as necessary. Thereby, it can adjust to desired pH. The pH adjuster is not particularly limited, but for example, inorganic acid components such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid and boric acid; basic such as sodium hydroxide, ammonia, imidazole, potassium hydroxide and calcium hydroxide Ingredients (basic pH adjuster) can be mentioned. The pH can also be adjusted using an organic acid component. When the polishing liquid is used for semiconductor polishing, ammonia or an acid component can be used.

The content of the basic pH adjusting agent contained in the polishing liquid is based on the total mass of the polishing liquid from the viewpoint of suppressing the occurrence of dent defects in the stopper (polishing stop layer made of a stopper material such as polysilicon). It is less than 1.3 × 10 ⁻² molmol / kg. From the same viewpoint, the content of the basic pH adjusting agent is preferably 1.4 × 10 ⁻² mol / kg or less, more preferably 6.0 × 10 ^{−3 based on} the total mass of the polishing liquid. mol / kg or less, still more preferably not more than 5.0 × ¹⁰ -3 mol / kg, particularly preferably less than 5.0 × ¹⁰ -3 mol / kg, very preferably 4.0 × 10 ^{- It is 3} mol / kg or less, and more preferably less than 4.0 × 10 ⁻³ mol / kg. The lower limit of the content of the basic pH adjuster is not particularly limited, but from the viewpoint of adjusting to a pH at which good storage stability of the abrasive grains is obtained, 1.0 × 10 6 based on the total mass of the polishing liquid. ⁻⁴ mol / kg, 1.2 × 10 ⁻⁴ mol / kg, or 1.8 × 10 ⁻⁴ mol / kg.

(PH)
The pH of the polishing liquid is preferably 4.0 or more, more preferably 4.5 or more, still more preferably 4.7 or more, and particularly preferably 5.0 or more. The pH of the polishing liquid is preferably 6.0 or less, more preferably 5.8 or less, still more preferably 5.7 or less, and particularly preferably 5.6 or less. When the pH is 4.0 to 6.0, excellent storage stability can be obtained while having an excellent polishing rate of the insulating material. Moreover, there is a tendency that the amount of dishing can be reduced and the surface flatness can be improved while suppressing the occurrence of dent defects in the stopper. That is, when the pH of the polishing liquid is 4.0 or more, the storage stability of the abrasive grains is improved, so that the aggregation of the abrasive grains is less likely to occur, and the dishing amount that makes it easy to suppress the occurrence of dent defects is reduced. There exists a tendency for the effect of becoming easy to reduce etc. to be acquired. Further, if the pH of the polishing liquid is 6.0 or less, the dishing amount can be reduced while suppressing the occurrence of dent defects, and the surface flatness tends to be sufficiently secured. From these viewpoints, the pH of the polishing liquid is preferably 4.0 to 6.0, more preferably 4.5 to 6.0, still more preferably 4.7 to 6.0, particularly Preferably it is 5.0 to 6.0, very preferably 5.0 to 5.8, even more preferably 5.0 to 5.7, very preferably 5.0 to 5.6. It is. The pH of the polishing liquid may be 4.5 to 5.8 or 4.7 to 5.6.

  The pH of the polishing liquid can be measured using a pH meter (for example, Model PH81 (trade name) manufactured by Yokogawa Electric Corporation). Specifically, for example, a pH meter is calibrated at two points using a phthalate pH buffer solution (pH: 4.01) and a neutral phosphate pH buffer solution (pH: 6.86) as standard buffers. After that, the electrode of the pH meter is put into the polishing liquid, and the value after being stabilized at 25 ° C. for 2 minutes or more is measured. At this time, both the standard buffer solution and the polishing solution are set to 25 ° C.

(water)
Although it does not restrict | limit especially as water, Deionized water, ion-exchange water, ultrapure water, etc. are preferable. The water content is not particularly limited as long as it is the remainder of the content of each of the above-described components and is contained in the polishing liquid. The polishing liquid may further contain a solvent other than water (for example, a polar solvent such as ethanol or acetone) as necessary.

(Other additives)
The polishing liquid according to this embodiment can contain abrasives, a water-soluble compound A, a polymer compound B, a pH adjuster, and other additives different from water. Examples of other additives include water-soluble polymer compounds (excluding water-soluble compound A and polymer compound B), dispersants, organic acid components, and the like. Examples of the water-soluble polymer compound include alginic acid, pectic acid, carboxymethylcellulose, agar, curdlan, pullulan, dextrin, cyclic dextrin and other polysaccharides.

  When the polishing liquid is stored separately in the cerium slurry and the additive liquid, preferably, other additives are contained in the additive liquid. These additives may be used alone or in combination of two or more.

  The constituent components of the polishing liquid according to the present embodiment may be stored in two or more liquids so as to be the polishing liquid. For example, a two-component type polishing liquid set composed of abrasive grains containing cerium and cerium slurry containing water (first liquid) and an additive liquid containing water-soluble compound A and water (second liquid). It may be stored as (for example, a CMP polishing liquid set), and the polishing liquid may be obtained by mixing both. In this case, components (polymer compound B, pH adjuster, etc.) other than the abrasive grains may be contained in the second liquid. The pH adjuster may be contained in the first liquid as long as the polarity of the potential of the abrasive grains contained in the first liquid does not change. Each component described in “Other additives” is preferably contained in the second liquid. The constituents of the polishing liquid may be stored as a polishing liquid set divided into three or more liquids.

  In the polishing liquid set, the slurry and additive liquid are mixed immediately before or during polishing to prepare the polishing liquid. Further, the one-part polishing liquid is stored as a stock liquid for polishing liquid with a reduced water content, and may be used by diluting with water immediately before polishing or at the time of polishing. The two-component polishing liquid set is stored as a slurry storage liquid and an additive liquid storage liquid with a reduced water content, and may be diluted with water immediately before or during polishing.

  Hereinafter, although an example of an experiment explains the present invention, the present invention is not limited to these examples.

<Preparation of abrasive grains>
40 kg of commercially available cerium carbonate hydrate was placed in an alumina container and baked in air at 830 ° C. for 2 hours to obtain 20 kg of yellowish white powder. When the phase of this powder was identified by the X-ray diffraction method, it was confirmed to be cerium oxide. 20 kg of the obtained cerium oxide powder was dry-ground using a jet mill to obtain a cerium oxide powder containing cerium oxide particles (abrasive grains).

<Preparation of water-soluble compound A>
Polyethylene glycol (Daiichi Kogyo Seiyaku Co., Ltd., trade name: PGE-4000) was prepared as the water-soluble compound A.

<Preparation of polymer compound B>
As the polymer compound B-1, polyacrylic acid having a weight average molecular weight of 2500 (sodium polyacrylate conversion value) was prepared. Moreover, the ammonium polyacrylate of the weight average molecular weight 8000 (polyacrylic acid sodium conversion value) was prepared as high molecular compound B-2.

<Preparation of basic pH adjuster>
As the basic pH adjuster 1, ammonia (25% by mass aqueous solution) was prepared. Moreover, imidazole was prepared as the basic pH adjuster 2.

<Preparation of test wafer for evaluation>
As the first evaluation test wafer and the second evaluation test wafer, blanket wafers (Blanket wafers) having no pattern structure shown below were prepared.
First test wafer for evaluation: wafer having a silicon oxide film having a thickness of 1000 nm formed on a silicon (Si) substrate (diameter: 200 mm) using a TEOS-plasma CVD method (p-TEOS wafer)
Second test wafer for evaluation: wafer having a polysilicon film on a silicon (Si) substrate (diameter: 200 mm)

<Preparation of polishing liquid (CMP polishing liquid)>
(Experimental example 1)
200.0 g of cerium oxide powder prepared as described above and 795.0 g of deionized water were mixed, and 5 g of an aqueous solution of ammonium polyacrylate (an aqueous solution containing 40% by mass of polymer compound B-2) was added and stirred. Then, ultrasonic dispersion was performed to obtain a cerium oxide dispersion. Ultrasonic dispersion was performed at an ultrasonic frequency of 400 kHz and a dispersion time of 20 minutes.

  Thereafter, 1 kg of cerium oxide dispersion was placed in a 1 L container (height: 170 mm) and allowed to stand, and sedimentation classification was performed. After 15 hours of classification time, the supernatant above a depth of 130 mm from the water surface was pumped up. The obtained supernatant cerium oxide dispersion was diluted with deionized water so that the solid content was 5% by mass to obtain a cerium oxide slurry containing cerium oxide and polymer compound B-2.

  In order to measure the average particle diameter (D50) of cerium oxide in the cerium oxide slurry, the slurry was diluted so that the measurement transmittance (H) with respect to the He—Ne laser was 60 to 70% to obtain a measurement sample. . When D50 of the measurement sample was measured with a laser diffraction particle size distribution meter (manufactured by Horiba, Ltd., trade name: LA-920, refractive index: 1.93, light source: He—Ne laser, absorption 0), the value of D50 Was 150 nm.

The prepared cerium oxide slurry, water-soluble compound A, polymer compound B-1 and pure water are mixed to obtain a mixed solution, and then basic pH adjuster 1 is added to the mixed solution. The pH was adjusted to 5.3. Thereby, 1.0 mass% of cerium oxide particles (abrasive grains), 0.10 mass% of water-soluble compound A, 0.20 mass% of polymer compound B-1, and polymer compound B-2 Of 0.01% by mass and 0.0075% by mass (4.40 × 10 ⁻³ mol / kg) of basic pH adjuster 1 were obtained (content standard: polishing liquid Total mass).

The pH of the polishing liquid was measured according to the following.
Measuring instrument: pH meter (trade name: Model PH81, manufactured by Yokogawa Electric Corporation)
Measurement method: After calibrating two pH meters using phthalate pH buffer solution (pH: 4.01) and neutral phosphate pH buffer solution (pH: 6.86) as standard buffers Then, the pH meter electrode was placed in the polishing liquid, and the value after 2 minutes or more had elapsed at 25 ° C. was measured. At this time, both the standard buffer solution and the polishing solution were set to 25 ° C.

(Experimental example 2)
Except that the amount of the polymer compound B-1 and the basic pH adjuster 1 and the pH were changed, and in the same manner as in Experimental Example 1, the cerium oxide particles (abrasive grains) were 1.0% by mass, water-soluble. Compound A is 0.10% by mass, polymer compound B-1 is 0.15% by mass, polymer compound B-2 is 0.01% by mass, and basic pH adjuster 1 is 0.0057% by mass. A polishing liquid having a pH of 5.5 containing (3.35 × 10 ⁻³ mol / kg) was obtained (content standard: total mass of the polishing liquid).

(Experimental example 3)
Except having changed the quantity of the high molecular compound B-1 and the basic pH adjuster 1, it carried out similarly to Experimental example 1, 1.0 mass% of cerium oxide particles (abrasive grain), and 0 for the water-soluble compound A 10% by mass, 0.15% by mass of the polymer compound B-1, 0.01% by mass of the polymer compound B-2, and 0.004% by mass of the basic pH adjuster 1 (2.35). A polishing liquid having a pH of 5.3 containing x10 ⁻³ mol / kg) was obtained (content standard: total mass of the polishing liquid).

(Experimental example 4)
Except that the amount of the polymer compound B-1 and the basic pH adjuster 1 and the pH were changed, and in the same manner as in Experimental Example 1, the cerium oxide particles (abrasive grains) were 1.0% by mass, water-soluble. Compound A is 0.10% by mass, polymer compound B-1 is 0.10% by mass, polymer compound B-2 is 0.01% by mass, and basic pH adjuster 1 is 0.0055% by mass. A polishing liquid having a pH of 5.7 containing (3.23 × 10 ⁻³ mol / kg) was obtained (content standard: total mass of the polishing liquid).

(Experimental example 5)
Except that the amount of the polymer compound B-1 and the basic pH adjuster 1 and the pH were changed, and in the same manner as in Experimental Example 1, the cerium oxide particles (abrasive grains) were 1.0% by mass, water-soluble. Compound A is 0.10% by mass, polymer compound B-1 is 0.10% by mass, polymer compound B-2 is 0.01% by mass, and basic pH adjuster 1 is 0.004% by mass. A polishing liquid having a pH of 6.0 (2.35 × 10 ⁻³ mol / kg) was obtained (content standard: total mass of the polishing liquid).

(Experimental example 6)
Except that the amount of the polymer compound B-1 and the basic pH adjuster 1 and the pH were changed, and in the same manner as in Experimental Example 1, the cerium oxide particles (abrasive grains) were 1.0% by mass, water-soluble. Compound A is 0.10% by mass, polymer compound B-1 is 0.10% by mass, polymer compound B-2 is 0.01% by mass, and basic pH adjuster 1 is 0.0013% by mass. A polishing liquid having a pH of 5.0 containing (7.63 × 10 ⁻⁴ mol / kg) was obtained (content standard: total mass of the polishing liquid).

(Experimental example 7)
Except that the amount of the polymer compound B-1 and the basic pH adjuster 1 and the pH were changed, and in the same manner as in Experimental Example 1, the cerium oxide particles (abrasive grains) were 1.0% by mass, water-soluble. Compound A is 0.10% by mass, polymer compound B-1 is 0.05% by mass, polymer compound B-2 is 0.01% by mass, and basic pH adjuster 1 is 0.002% by mass. A polishing liquid having a pH of 5.7 containing (1.17 × 10 ⁻³ mol / kg) was obtained (content standard: total mass of the polishing liquid).

(Experimental example 8)
Except that the amount of the polymer compound B-1 and the basic pH adjuster 1 and the pH were changed, and in the same manner as in Experimental Example 1, the cerium oxide particles (abrasive grains) were 1.0% by mass, water-soluble. Compound A is 0.10% by mass, polymer compound B-1 is 0.05% by mass, polymer compound B-2 is 0.01% by mass, and basic pH adjuster 1 is 0.0003% by mass. A polishing liquid having a pH of 5.0 containing (1.76 × 10 ⁻⁴ mol / kg) was obtained (content standard: total mass of the polishing liquid).

(Experimental example 9)
The same as in Experimental Example 1 except that the basic pH adjuster 2 was used instead of the basic pH adjuster 1, the amounts of the polymer compound B-1 and the basic pH adjuster, and the pH were changed. Cerium oxide particles (abrasive grains) 1.0% by mass, water-soluble compound A 0.10% by mass, polymer compound B-1 0.10% by mass, and polymer compound B-2 A polishing liquid having a pH of 5.0 containing 0.01% by mass and 0.0029% by mass (4.26 × 10 ⁻⁴ mol / kg) of basic pH adjuster 2 was obtained (content standard: Total mass of polishing liquid).

<Evaluation>
(Polishing selectivity evaluation)
The first evaluation test wafer and the second evaluation test wafer were each polished using a polishing apparatus (manufactured by APPLIED MATERIALS, trade name: Mirra). Specifically, first, an evaluation test wafer was set in a holder to which a suction pad for mounting a substrate was attached. Next, a polishing pad made of porous urethane resin (Rohm and Haas Japan Co., Ltd., model number: IC1000) was attached to the polishing surface plate of the polishing apparatus. The holder was placed on the polishing platen with the surface on which the insulating film (silicon oxide film) or polysilicon film as the film to be polished was placed facing down, and the processing load was set to 3.6 psi (about 25 kPa). Next, while dropping the abrasive liquid to the polishing platen at a rate of 200 mL / min, and an evaluation test wafer and the polishing surface plate respectively ^93Min -1, rotated at 87Min ^-1, an evaluation test wafer Polished for 60 seconds. The polished wafer was thoroughly washed with pure water and then dried.

  Using an optical interference type film thickness measuring device (product name: RE-3000, manufactured by SCREEN Semiconductor Solutions Co., Ltd.), the film thicknesses of the silicon oxide film and the polysilicon film before and after polishing are measured, and the average value of the film thickness change amount Was divided by the polishing time to calculate the polishing rate (unit: nm / min) of silicon oxide and polysilicon in the blanket wafer. From the obtained polishing rate, the polishing rate ratio of silicon oxide to polysilicon (silicon oxide polishing rate / polysilicon polishing rate) was determined. In Experimental Example 1, the polishing rate ratio was in the range of 10-50. In Experimental Examples 2 to 9, a polishing rate ratio exceeding 50 was obtained.

(Evaluation of dent defects)
Using an optical microscope (manufactured by Olympus Corporation, trade name: DSX-510), the central portion of the second evaluation test wafer after polishing obtained by polishing selectivity evaluation with a setting of 20 × objective lens is 5 I took a picture. Then, the number of dent defects per photographed image was counted, and the average value of the five images was determined as the number of dent defects (unit: piece / field of view). In Experimental Examples 1 to 9, it was confirmed that the number of dent defects was 10.

  DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 20 ... Stopper, 30 ... Insulating part, 100 ... Structure, 200 ... To-be-polished body.

Claims (2)

A structure comprising a substrate having a plurality of convex portions and concave portions on the surface, a stopper disposed on the convex portion of the substrate, and an insulating portion disposed in the concave portion of the substrate,
The stopper includes polysilicon;
The stopper and the insulating part are exposed on the surface of the structure,
In the surface of the structure, the surface of the stopper disposed on at least one of the convex portions has no dent defect. A substrate having a plurality of convex portions and concave portions on the surface, a stopper disposed on the convex portion of the substrate, and an insulating portion disposed on the stopper and disposed on the concave portion of the substrate. Polishing and removing the insulating portion of the object to be polished until the stopper is exposed, thereby obtaining a structure having a surface with the stopper and the insulating portion exposed;
The stopper includes polysilicon;
The manufacturing method of a structure, wherein the surface of the stopper disposed on at least one of the convex portions does not have a dent defect on the surface of the structure.