JP2015129217A - Polishing agent, polishing agent set and method for polishing substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing agent, a polishing agent set and a polishing method capable of obtaining a polishing speed for a useful insulating material and improving smoothness of a substrate surface.SOLUTION: There is provided a polishing agent which comprises water, cerium oxide particles, saccharides having 140 or less carbon atoms, a nonionic surfactant and an organic acid, where the cerium oxide particles are single-crystal particles, the surface potential in the polishing agent is negative. The primary particle diameter (crystallite diameter) of abrasive grains is 1 nm or more and 300 nm or less.

Description

  The present invention relates to an abrasive, an abrasive set, and a method for polishing a substrate using the abrasive or the abrasive set. In particular, the present invention relates to an abrasive used in a planarization process of a substrate surface, a polishing agent set, and a polishing method for a substrate using the polishing agent or the polishing agent set, which is a manufacturing technique of a semiconductor element. More specifically, the present invention relates to a polishing agent and a polishing agent set used in a planarization process of a shallow trench isolation (shallow trench isolation, hereinafter referred to as “STI”) insulating material, premetal insulating material, interlayer insulating material, and the like. Further, the present invention relates to a method for polishing a substrate using the abrasive or the abrasive set.

  In recent semiconductor device manufacturing processes, the importance of processing technology for higher density and miniaturization is increasing. CMP (Chemical Mechanical Polishing), which is one of the processing techniques, is used to form STI, planarize premetal insulating material or interlayer insulating material, plug or embedded metal wiring in the manufacturing process of semiconductor devices. This technology is essential for formation.

  The most frequently used CMP abrasive is a silica-based CMP abrasive containing silica (silicon oxide) particles such as fumed silica and colloidal silica as abrasive grains. Silica-based CMP abrasives are characterized by high versatility, and a wide variety of materials can be polished regardless of insulating materials or conductive materials by appropriately selecting the abrasive content, pH, additives, and the like.

  On the other hand, the demand for CMP abrasives containing cerium compound particles as abrasive grains, mainly for insulating materials such as silicon oxide, is increasing. For example, a cerium oxide-based CMP abrasive containing cerium oxide (ceria) particles as abrasive grains can polish silicon oxide at high speed even with a lower abrasive grain content than silica-based CMP abrasives (for example, Patent Documents 1 and 2 below) reference).

  However, in recent years, in the manufacturing process of semiconductor elements, it has been required to achieve further miniaturization of wiring, and polishing scratches that occur during polishing have become a problem. That is, even when a fine polishing flaw occurs when polishing using a conventional cerium oxide-based abrasive, there is no problem if the size of the polishing flaw is smaller than the conventional wiring width. However, when trying to achieve further miniaturization of the wiring, there is a problem even if the polishing scratches are minute.

  By the way, as a conventional cerium oxide-based abrasive, there is known a method (hereinafter referred to as “calcination method”) in which a cerium raw material is fired and pulverized to obtain cerium oxide particles. Particles obtained by the firing method remove large particles that cause abrasive scratches in the purification step. However, large particles that could not be removed and mixed into the abrasive were the main cause of polishing scratches.

  As a method for fundamentally preventing the mixing of coarse cerium oxide particles that cannot be pulverized, a method for producing fine cerium oxide particles without using pulverization has been studied (for example, the following patent document). 3). These techniques are intended to obtain a suspension of cerium oxide particles by a manufacturing method using a crystal growth method, and can be used as an abrasive. In the cerium oxide particles thus obtained, each particle becomes a single crystal.

Japanese Patent Laid-Open No. 10-106994 Japanese Patent Application Laid-Open No. 08-022970 Special table 2010-505735 gazette

  By the way, in the CMP process for forming the STI, polysilicon, silicon nitride, or the like is used as a constituent material of the stopper (polishing stop layer) (hereinafter referred to as “stopper material”). Usually, the polishing is generally stopped when an insulating material such as silicon oxide is polished and the portion of the stopper material is exposed. In this case, for the purpose of improving the flatness and suppressing erosion (overpolishing of the stopper material), an additive capable of improving the flatness and an additive capable of suppressing the polishing of the stopper material are added. This improves the smoothness of the substrate surface after polishing.

  Abrasives using cerium oxide particles obtained by the firing method can improve flatness and polishing selectivity by using polycarboxylic acid-based anionic polymer polymers and nonionic water-soluble polymers as additives. did it. However, it is difficult to obtain a polishing rate of an insulating material useful for the STI CMP process when the additive is used for the cerium oxide particles produced by the crystal growth method.

  The present invention is intended to solve such a technical problem. In addition to cerium oxide particles obtained by a firing method, single crystal cerium oxide particles produced by a crystal growth method are used as abrasive grains. It is an object of the present invention to provide a polishing agent, a polishing agent set and a polishing method capable of obtaining a polishing rate of a useful insulating material and improving the smoothness of a substrate surface even with a polishing agent that has been used. To do.

  The present invention is an abrasive containing water, cerium oxide particles, a saccharide having 140 or less carbon atoms, a nonionic surfactant, and an organic acid, wherein the cerium oxide particles are single crystals. The present invention relates to an abrasive that is a particle and has a negative surface potential in the abrasive.

  The cerium oxide particles may have a negative surface potential in the abrasive by being dispersed in water using an anionic dispersant. The cerium oxide particles are preferably produced by a crystal growth method.

Moreover, this invention relates to the said abrasive | polishing agent whose primary particle diameter is 1 nm or more and 300 nm or less.
The present invention also relates to the above abrasive, wherein the primary particle diameter of the abrasive grains is 1 nm or more and 300 nm or less, and the primary particle diameter of 160 nm or less is 90% or more of the whole.
The present invention also relates to the above abrasive, wherein the primary particle diameter of the abrasive grains is 1 nm or more and 300 nm or less, and the primary particle diameter of 160 nm or less is 99% or more of the whole.
The primary particle diameter of the abrasive grains refers to the crystallite diameter of the abrasive grains.

Moreover, this invention relates to the said abrasive | polishing agent whose saccharide | sugar does not contain a carboxyl group in a structure.
Moreover, this invention relates to the said abrasive | polishing agent whose organic acid is C4 or less monocarboxylic acid.

  According to the polishing agent of the present invention, even when single-crystal or cerium oxide particles produced by a crystal growth method are used as abrasive grains, the stopper material does not excessively decrease the polishing rate of the insulating material. It is possible to improve the polishing selectivity of the insulating material with respect to. Thereby, a highly flat surface can be obtained. In addition, according to the polishing agent of the present invention, these insulating materials can be highly planarized, particularly in CMP technology for planarizing STI insulating materials, premetal insulating materials, interlayer insulating materials, and the like. Furthermore, according to the abrasive | polishing agent which concerns on this invention, an insulating material can also be grind | polished with a low grinding | polishing damage | wound, planarizing an insulating material highly.

  The content of saccharides having 140 or less carbon atoms is preferably 0.1% by mass or more based on the total mass of the abrasive. Thereby, the flatness of the surface to be polished can be improved without reducing the polishing rate of the insulating material.

  The content of the nonionic surfactant is preferably 0.01% by mass or more based on the total mass of the abrasive. Thereby, the flatness on the surface to be polished can be improved while improving the polishing selectivity of the insulating material with respect to the stopper material without reducing the polishing rate of the insulating material.

  The crystallite size (primary particle size) of the cerium oxide particles is preferably 1 nm or more and 300 nm or less. Thereby, generation | occurrence | production of a grinding | polishing damage | wound can be suppressed, further improving the polishing selectivity of the insulating material with respect to a stopper material, without reducing the grinding | polishing speed | rate of an insulating material.

  The content of the cerium oxide particles is preferably 0.1% by mass or more and 5% by mass or less based on the total mass of the abrasive. Thereby, generation | occurrence | production of a grinding | polishing damage | wound can be suppressed, further improving the polishing selectivity of the insulating material with respect to a stopper material, without reducing the grinding | polishing speed | rate of an insulating material.

  The pH of the abrasive according to the present invention is preferably 4.0 or more and 7.0 or less. Accordingly, it is possible to suppress the occurrence of polishing flaws while further improving the flatness on the surface to be polished and the polishing selectivity of the insulating material with respect to the stopper material without reducing the polishing speed of the insulating material.

  Another aspect of the present invention relates to the use of the abrasive in a polishing method for polishing a surface to be polished containing silicon oxide. That is, the abrasive according to the present invention is preferably used for polishing a surface to be polished containing silicon oxide.

  In the abrasive set according to the present invention, the constituents of the abrasive are stored separately in a plurality of liquids, the first liquid contains the cerium oxide particles, and the second liquid is a saccharide having 140 or less carbon atoms. , Nonionic surfactants and organic acids. According to the abrasive set according to the present invention, the flatness on the surface to be polished and the polishing selectivity of the insulating material with respect to the stopper material can be improved without excessively reducing the polishing rate of the insulating material.

  The substrate polishing method of the present invention may comprise a step of polishing the surface to be polished of the substrate using the abrasive, and the first liquid and the second liquid in the abrasive set are mixed. You may provide the process of grind | polishing the to-be-polished surface of a base | substrate using the obtained abrasive | polishing agent. According to these polishing methods, by using the polishing agent or the polishing agent set, flatness on the surface to be polished can be achieved without excessively reducing the polishing rate of the insulating material as compared with the case of using the conventional polishing agent. The occurrence of polishing flaws can be suppressed while improving the polishing selectivity of the insulating material with respect to the stopper material.

  The substrate polishing method of the present invention may be a polishing method in which the substance to be removed is an insulating material and the stopper material is polysilicon. That is, the method for polishing a substrate according to the present invention is a method for polishing a substrate having an insulating material and polysilicon, and includes a step of selectively polishing the insulating material with respect to polysilicon using the abrasive. Alternatively, a step of selectively polishing the insulating material with respect to polysilicon using an abrasive obtained by mixing the first liquid and the second liquid in the abrasive set may be provided. According to these polishing methods, by using the polishing agent or the polishing agent set, flatness on the surface to be polished can be achieved without excessively reducing the polishing rate of the insulating material as compared with the case of using the conventional polishing agent. The occurrence of polishing flaws can be suppressed while improving the polishing selectivity of the insulating material with respect to the stopper material.

  According to the present invention, for example, even when cerium oxide particles that are single crystals produced by a crystal growth method are used as abrasive grains, flatness on the surface to be polished can be achieved without excessively reducing the polishing rate of the insulating material. Further, it is possible to provide a polishing agent, a polishing agent set and a polishing method capable of suppressing the generation of polishing flaws while improving the polishing selectivity of the insulating material with respect to the stopper material. In addition, according to the present invention, in particular, in CMP technology for flattening an STI insulating material, a premetal insulating material, an interlayer insulating material, etc., the flatness on the surface to be polished without excessively reducing the polishing rate of the insulating material, A polishing agent, a polishing agent set, and a polishing method that can suppress the generation of polishing flaws while improving the polishing selectivity of the insulating material with respect to the stopper material can be provided. Furthermore, according to the present invention, the insulating material can be polished with low polishing scratches while the insulating material is highly planarized.

It is a schematic cross section which shows the pattern wafer used in the Example.

  Hereinafter, the abrasive | polishing agent which concerns on embodiment of this invention, an abrasive | polishing agent set, and the grinding | polishing method of the base | substrate using the said abrasive | polishing agent or the said abrasive | polishing agent set are demonstrated in detail.

  The abrasive | polishing agent which concerns on this embodiment is a composition which touches a to-be-polished surface at the time of grinding | polishing, for example, is a CMP abrasive | polishing agent. Specifically, the abrasive according to this embodiment contains at least water, cerium oxide particles, a saccharide having 140 or less carbon atoms, a nonionic surfactant, and an organic acid, and the cerium oxide. These particles are single crystal particles and have a negative surface potential in the abrasive. Hereafter, each component and the component which can be added arbitrarily are demonstrated.

(Abrasive grains)
The abrasive according to the present embodiment includes cerium oxide particles, which are single crystal particles, and have a negative surface potential in the abrasive. Due to the single crystal particles having a negatively charged surface potential, generation of defects such as polishing scratches can be suppressed. The surface potential can be measured, for example, using a product name: Delsa NanoC manufactured by Beckman Coulter. The surface potential is not particularly limited, but is usually −250 to −5 mV. The abrasive grains are preferably single-crystal cerium oxide particles that have been anion-dispersed. The “single crystal cerium oxide particles” are single crystal cerium oxide particles having no crystal grain boundaries, and can be produced by, for example, the method described in Patent Document 3.

  The abrasive | polishing agent which concerns on this embodiment can contain particle | grains other than the said cerium oxide particle as an abrasive grain. Examples of such particles include cerium oxide particles, silica particles, alumina particles, zirconia particles, and resin particles obtained by a firing method.

  The crystallite size of the single crystal cerium oxide particles is preferably 1 nm or more and 300 nm or less. The crystallite diameter can be measured by a TEM photograph image or an SEM image. Further, the primary particle diameter of 160 nm or less is more preferably 90% or more of the whole, and particularly preferably 99% or more of the whole. By being 90% or more, it is possible to suppress the occurrence of polishing flaws while further improving the polishing selectivity of the insulating material with respect to the stopper material without reducing the polishing speed of the insulating material. Note that “90% or more of the whole” is in terms of the number of single crystal cerium oxide particles.

  From the viewpoint of further improving the polishing rate of the insulating material, the lower limit of the crystallite diameter of the single crystal cerium oxide particles in the abrasive or the abrasive set described later is preferably 1 nm or more, more preferably 10 nm or more, and 20 nm or more. Further preferred. The upper limit of the crystallite diameter of the single crystal cerium oxide particles is preferably 300 nm or less, more preferably 200 nm or less, still more preferably 150 nm or less, and particularly preferably 100 nm or less, from the viewpoint of further suppressing scratches on the polished surface. 60 nm or less is extremely preferable. From the above viewpoint, the crystallite diameter of the single crystal cerium oxide particles is more preferably 1 nm or more and 300 nm or less. Furthermore, the average particle diameter of the secondary particles of the cerium oxide particles is preferably 1 nm or more and 150 nm or less. Thereby, generation | occurrence | production of a grinding | polishing damage | wound can be suppressed, further improving the polishing selectivity of the insulating material with respect to a stopper material, without reducing the grinding | polishing speed | rate of an insulating material.

  When the cerium oxide particles are aggregated, for example, a dispersing agent described later can be used for dispersion using a homogenizer, an ultrasonic disperser, a wet ball mill, or the like, in addition to a dispersion treatment using a normal stirrer.

  As a method for further reducing the average particle size of the secondary particles of the cerium oxide particles dispersed by the above method, for example, a sedimentation classification method can be used. The sedimentation classification method is a method in which slurry is forcedly settled after being centrifuged with a small centrifuge and only the supernatant liquid is taken out. In addition, a high-pressure homogenizer that collides the cerium oxide particles in the dispersion medium with each other at high pressure may be used.

  From the viewpoint of further improving the polishing rate of the insulating material, the lower limit of the average particle size of the abrasive grains in the slurry or the abrasive set described later is preferably 1 nm or more, more preferably 10 nm or more, and 20 nm or more. Further preferred. The upper limit of the average particle size of the abrasive grains is preferably 150 nm or less, more preferably 140 nm or less, still more preferably 130 nm or less, particularly preferably 120 nm or less, and 110 nm or less, from the viewpoint of further suppressing scratches on the surface to be polished. Is very preferred. From the above viewpoint, the average grain size of the abrasive grains is more preferably 1 nm or more and 150 nm or less.

  Specifically, the average particle size of the cerium oxide particles is obtained by diluting the CMP polishing liquid or slurry to be measured to a concentration suitable for measurement, and putting this measurement sample into the laser diffraction / scattering particle size distribution analyzer. Can be measured. More specifically, the average particle diameter of the cerium oxide particles can be measured as follows using LA-920 (light source: He—Ne laser and W laser) manufactured by Horiba, Ltd. First, a measurement sample is obtained by diluting the CMP polishing liquid or slurry to be measured to a concentration suitable for measurement so that the transmittance (H) during measurement with respect to the He—Ne laser becomes 60 to 70%. And this measurement sample is thrown into LA-920, and an average particle diameter is obtained as an arithmetic average diameter (mean size) obtained at that time.

  The content of abrasive grains in the slurry in the abrasive or the abrasive set described later is preferably 0.1 to 5 mass%, more preferably 0.1 to 3.0 mass%, based on the total mass of the CMP polishing liquid. Preferably, 0.2 to 2.0 mass% is more preferable, and 0.3 to 1.5 mass% is particularly preferable.

  The content of the cerium oxide particles in the slurry in the abrasive or the abrasive set described later is preferably 0.1 to 5% by mass, and 0.1 to 3.0% by mass based on the total mass of the CMP polishing liquid. More preferably, 0.2-2.0 mass% is still more preferable, and 0.3-1.5 mass% is especially preferable.

  The abrasive according to this embodiment may include a water-soluble dispersant. Thereby, the cerium oxide particles can be more stably dispersed in water. Here, that the dispersant is water-soluble is defined as having a solubility in water of 0.1% by mass or more.

  The dispersant is not particularly limited as long as it can be dissolved in water, and specific examples include an anionic dispersant, a cationic dispersant, a nonionic dispersant, and an amphoteric dispersant. An anionic dispersant is preferable from the viewpoint of making the surface potential of abrasive grains containing cerium oxide particles negative in the abrasive. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the anionic dispersant include lauryl sulfate triethanolamine, ammonium lauryl sulfate, polyoxyethylene alkyl ether sulfate triethanolamine, and polycarboxylic acid type polymer dispersants. Among them, cerium oxide particles are used. A polycarboxylic acid type polymer dispersant is preferred from the viewpoint of easily making the surface potential of the abrasive grains contained negative. These can be used individually by 1 type or in combination of 2 or more types.

The weight average molecular weight of the polycarboxylic acid type polymer dispersant is preferably 100,000 or less. In addition, a weight average molecular weight can be measured using GPC on the following conditions, for example.
(conditions)
Sample: 10 μL
Standard polystyrene: Standard polystyrene manufactured by Tosoh Corporation (molecular weight: 190000, 17900, 9100, 2980, 578, 474, 370, 266)
Detector: manufactured by Hitachi, Ltd., RI-monitor, trade name “L-3000”
Integrator: Hitachi, Ltd., GPC integrator, product name “D-2200”
Pump: Hitachi, Ltd., trade name “L-6000”
Degassing device: Showa Denko Co., Ltd., trade name "Shodex DEGAS"
Column: Hitachi Chemical Co., Ltd., trade names “GL-R440”, “GL-R430”, “GL-R420” connected in this order and used as eluent: tetrahydrofuran (THF)
Measurement temperature: 23 ° C
Flow rate: 1.75 mL / min Measurement time: 45 minutes

(Additive)
The abrasive | polishing agent which concerns on this embodiment can contain an additive. Here, the term “additive” refers to polishing properties such as polishing rate, flatness and polishing selectivity; and other than water and abrasive particles in order to adjust abrasive properties such as abrasive dispersibility and storage stability. Refers to a substance added to the abrasive.

[First additive: saccharides having 140 or less carbon atoms]
The abrasive according to this embodiment contains a saccharide having 140 or less carbon atoms as the first additive. The first additive can prevent the insulating material from being excessively polished after exposure of the stopper, thereby obtaining high flatness. It is presumed that when the first additive covers the insulating material, the progress of polishing by the abrasive grains is alleviated and the polishing rate is prevented from becoming excessively high.

  Examples of the saccharide having 140 or less carbon atoms include monosaccharides such as ribose, glucose, and fructose; sugar polymers such as sucrose, maltose, raffinose, dextrin, dextran, and cyclodextrin.

  In addition, in the saccharide contained in the abrasive according to the present embodiment, one or more hydroxyl groups may be substituted with hydrogen or amino groups, and a carbonyl group may be reduced. It is preferable not to use (uronic acid, aldaric acid, etc.). By not using a saccharide containing a carboxyl group, higher flatness can be obtained.

  A 1st additive can be used individually by 1 type or in combination of 2 or more types in order to adjust grinding | polishing characteristics, such as flatness.

The upper limit of the weight average molecular weight of the first additive is preferably 5000 or less, more preferably 4500 or less, still more preferably 4000 or less, particularly preferably 3500 or less, from the viewpoint of improving flatness on the polished surface. Is very preferred. Further, the lower limit of the weight average molecular weight of the first additive is preferably 90 or more, more preferably 100 or more, and still more preferably 110 or more, from the viewpoint of further improving the flatness on the polished surface. From the above viewpoint, the weight average molecular weight of the first additive is preferably 90 or more and 5000 or less. In addition, a weight average molecular weight can be measured on condition of the following by the gel permeation chromatography method (GPC) using the calibration curve of a standard polystyrene, for example.
Equipment used: Hitachi L-6000 (manufactured by Hitachi, Ltd.)
Column: Gel Pack GL-R420 + Gel Pack GL-R430 + Gel Pack GL-R440 [Hitachi Chemical Co., Ltd., trade name, total of 3]
Eluent: Tetrahydrofuran Measurement temperature: 40 ° C
Flow rate: 1.75 mL / min Detector: L-3300RI [manufactured by Hitachi, Ltd.]

  The lower limit of the content of the first additive is preferably 0.1% by mass or more and more preferably 0.3% by mass or more based on the total mass of the abrasive from the viewpoint of further improving the flatness on the polished surface. Preferably, 0.5 mass% or more is more preferable. The upper limit of the content of the first additive is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, based on the total mass of the abrasive, from the viewpoint of obtaining an appropriate polishing rate. 0 mass% or less is still more preferable. From the above viewpoint, the content of the first additive is preferably 0.1% by mass or more and 5.0% by mass or less based on the total mass of the abrasive. In addition, when using a some compound as a 1st additive, it is preferable that the sum total of content of each compound satisfy | fills the said range.

[Second additive: nonionic surfactant]
The abrasive | polishing agent which concerns on this embodiment contains a nonionic surfactant as a 2nd additive other than a 1st additive.

  By coating the stopper material, the second additive has an effect of suppressing an excessive increase in the polishing rate of the stopper material by the abrasive grains. Thereby, according to the abrasive | polishing agent which concerns on this embodiment, the grinding | polishing selectivity of the insulating material with respect to a stopper material can be improved.

  Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene polyoxypropylene ether derivative, polyoxypropylene glyceryl ether, and polyethylene. Ether type surfactants such as oxyethylene adducts of glycol, methoxypolyethylene glycol and acetylenic diols; ester type surfactants such as sorbitan fatty acid esters and glycerol borate fatty acid esters; amino ether type interfaces such as polyoxyethylene alkylamines Activator; polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycerol borate fatty acid ester, polyoxyethylene alkyl ester Ether ester surfactants such as fatty acid alkanolamides, alkanolamide surfactants such as polyoxyethylene fatty acid alkanolamides; oxyethylene adducts of acetylenic diols; polyvinylpyrrolidone; acrylamides such as polyacrylamide and polydimethylacrylamide A polymer etc. are mentioned.

  The content of the nonionic surfactant is preferably 0.01 to 1.0% by mass, more preferably 0.02 to 0.7% by mass, and 0.03 to 0% based on the total mass of the CMP polishing liquid. More preferably, 5% by mass. When the content of the nonionic surfactant is 1.0% by mass or less, the polishing rate of the silicon oxide film is further improved. When the content of the nonionic surfactant is 0.01% by mass or more, an increase in the polishing rate of the polysilicon film can be further suppressed. When a nonionic surfactant is used as the dispersant, the total amount of the nonionic surfactant as the dispersant and the nonionic surfactant in the additive solution satisfies the above range. Is preferred.

[Third additive: Organic acid]
The abrasive | polishing agent which concerns on this embodiment contains an organic acid as a 3rd additive.

  The third additive can obtain a useful polishing rate of the insulating material due to the effect of affecting the surface reactivity of the cerium oxide particles and the insulating material. Thereby, according to the abrasive | polishing agent which concerns on this embodiment, the grinding | polishing selectivity of the insulating material with respect to a stopper material can be improved.

  Examples of the organic acid include carboxylic acid and amino acid. These can be used individually by 1 type or in combination of 2 or more types. Among these, carboxylic acids and amino acids are preferred from the viewpoint of excellent balance between abrasive dispersibility and polishing characteristics.

  Carboxylic acid has the effect of stabilizing the pH and further improving the polishing rate of the insulating material. Examples of the carboxylic acid include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, lactic acid and the like, and acetic acid and propionic acid are preferable.

  An amino acid has an effect of improving the dispersibility of abrasive grains containing a hydroxide of a tetravalent metal element and further improving the polishing rate of the insulating material. Amino acids include arginine, lysine, aspartic acid, glutamic acid, asparagine, glutamine, histidine, proline, tyrosine, tryptophan, serine, threonine, glycine, alanine, β-alanine, methionine, cysteine, phenylalanine, leucine, valine, isoleucine, etc. And glycine and alanine are preferable. In addition, although an amino acid has a carboxyl group, it shall differ from carboxylic acid.

(Abrasive properties)
The lower limit of the pH (25 ° C.) of the abrasive according to this embodiment is preferably 4.0 or more, more preferably 4.2 or more, and even more preferably 4.4 or more, from the viewpoint of further improving the polishing rate of the insulating material. 4.6 or more is preferable. The upper limit of the pH is preferably 7.0 or less, more preferably 6.8 or less, and even more preferably 6.6 or less from the viewpoint of further improving the polishing rate of the insulating material. From the above viewpoint, the pH of the abrasive is preferably 4.0 or more and 7.0 or less.

  The pH of the abrasive can be adjusted by alkali components such as ammonia, sodium hydroxide, tetramethylammonium hydroxide (TMAH), and imidazole. A buffer may be added to stabilize the pH. Moreover, you may add a buffer as a buffer (liquid containing a buffer). Examples of such a buffer include acetate buffer and phthalate buffer.

  The pH of the abrasive according to this embodiment can be measured with a pH meter using a general glass electrode. Specifically, for example, trade name: Model (F-51) manufactured by HORIBA, Ltd. can be used for measuring pH. The pH of the additive solution is as follows: phthalate pH standard solution (pH: 4.01), neutral phosphate pH standard solution (pH: 6.86), and borate pH standard solution (pH: 9.18). ) Is used as a pH standard solution, the pH meter is calibrated at three points, the electrode of the pH meter is placed in the additive solution, and the value after 2 minutes has elapsed and stabilized is measured. At this time, the liquid temperatures of the standard buffer solution and the additive solution can both be 25 ° C., for example. The pH of the slurry can be measured by the same method.

  The abrasive according to this embodiment may be stored as a one-part abrasive containing at least abrasive grains, a first additive, a second additive, a third additive and water, A multiple liquid type (for example, two liquids) in which the constituents of the abrasive are divided into the slurry and the additive liquid so that the slurry (first liquid) and the additive liquid (second liquid) are mixed to become the abrasive. It may be stored as an abrasive set of formula). The slurry includes at least abrasive grains, for example. The additive liquid contains, for example, at least one selected from the group consisting of a first additive, a second additive, and a third additive. It is preferable that the first additive, the second additive, the third additive, the water-soluble polymer, and the buffering agent are included in the additive liquid among the slurry and the additive liquid. The constituents of the abrasive may be stored as an abrasive set divided into three or more liquids. For example, the constituents of the abrasive are stored separately in a slurry containing abrasive grains and water, an additive liquid containing a first additive and water, and an additive liquid containing a second additive and water. Also good.

  In the abrasive set, slurry and additive liquid are mixed immediately before or during polishing to produce an abrasive. In addition, the one-component abrasive is stored as an abrasive storage solution with a reduced water content, and may be diluted with water during polishing. The multi-liquid type abrasive set may be stored as a slurry storage solution or an additive storage solution with a reduced water content, and may be diluted with water during polishing.

  In the case of a one-pack type abrasive, as a method of supplying the abrasive onto the polishing surface plate, a method of feeding and supplying the abrasive directly; a storage solution for abrasive and water are sent through separate pipes, A method in which these are combined, mixed and supplied; a method in which an abrasive stock solution and water are mixed and supplied in advance can be used.

  When storing as a slurry set of multiple liquids divided into slurry and additive liquid, the polishing rate can be adjusted by arbitrarily changing the composition of these liquids. In the case of polishing using an abrasive set, methods for supplying the abrasive onto the polishing surface plate include the following methods. For example, the slurry and the additive liquid are sent through separate pipes, and these pipes are combined, mixed and supplied; the slurry storage liquid, the additive liquid storage liquid and water are sent through separate pipes, A method of supplying these by merging and mixing them; a method of supplying a mixture of slurry and additive solution in advance; a method of supplying a mixture of slurry storage solution, storage solution for additive solution and water in advance, etc. Can do. Moreover, the method of supplying the slurry and additive liquid in the said abrasive | polishing agent set on a polishing surface plate, respectively can also be used. In this case, the surface to be polished is polished using an abrasive obtained by mixing the slurry and the additive liquid on the polishing platen.

(Substrate polishing method)
The substrate polishing method according to the present embodiment may include a polishing step of polishing the surface to be polished of the substrate using the one-part polishing agent, and the slurry and additive liquid in the polishing agent set are mixed. You may provide the grinding | polishing process of grind | polishing the to-be-polished surface of a base | substrate using the obtained abrasive | polishing agent. Further, the substrate polishing method according to this embodiment may be a method for polishing a substrate having an insulating material and polysilicon. For example, the one-part abrasive or the slurry and additive liquid in the abrasive set And a polishing step of selectively polishing the insulating material with respect to polysilicon using a polishing agent obtained by mixing the above. In this case, the base may have, for example, a member containing an insulating material and a member containing polysilicon.

  In the polishing step, for example, the abrasive is supplied between the material to be polished and the polishing pad in a state where the material to be polished of the substrate having the material to be polished is pressed against the polishing pad (polishing cloth) of the polishing surface plate. The surface to be polished of the material to be polished is polished by relatively moving the substrate and the polishing surface plate. In the polishing step, for example, at least a part of the material to be polished is removed by polishing.

  Examples of the substrate to be polished include a substrate. For example, a material to be polished is formed on a substrate for manufacturing a semiconductor element (for example, a semiconductor substrate on which an STI pattern, a gate pattern, a wiring pattern, etc. are formed). A substrate is mentioned. Examples of materials to be polished include insulating materials such as silicon oxide; stopper materials such as polysilicon and silicon nitride. The material to be polished may be a single material or a plurality of materials. When a plurality of materials are exposed on the surface to be polished, they can be regarded as materials to be polished. The material to be polished may be in the form of a film, and may be a silicon oxide film, a polysilicon film, a silicon nitride film, or the like.

  The material to be polished (such as an insulating material such as silicon oxide) formed on such a substrate is polished with the above-mentioned abrasive and the excess portion is removed, thereby eliminating the unevenness on the surface of the material to be polished and A smooth surface can be formed over the entire surface of the abrasive material. The abrasive according to this embodiment is preferably used for polishing a surface to be polished containing silicon oxide.

  In this embodiment, an insulating material in a base body having an insulating material containing at least silicon oxide on the surface, a stopper (polishing stop layer) disposed under the insulating material, and a semiconductor substrate disposed under the stopper is polished. it can. The stopper material constituting the stopper is a material whose polishing rate is lower than that of the insulating material, and polysilicon, silicon nitride and the like are preferable. In such a base, since the polishing is stopped when the stopper is exposed, the insulating material can be prevented from being excessively polished, and thus the flatness of the insulating material after polishing can be improved. Stopping the polishing when the stopper is exposed means that the polishing is finished (with a predetermined thickness left) before all the stoppers are removed.

  As a method for producing a material to be polished by the polishing agent according to the present embodiment, a low pressure CVD method, a quasi-atmospheric pressure CVD method, a plasma CVD method or the like CVD method; a spin coating method in which a liquid material is applied to a rotating substrate Etc.

Silicon oxide can be obtained, for example, by thermally reacting monosilane (SiH ₄ ) and oxygen (O ₂ ) using a low pressure CVD method. Silicon oxide can be obtained, for example, by thermally reacting tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) and ozone (O ₃ ) using a quasi-atmospheric pressure CVD method. As another example, silicon oxide is similarly obtained by causing plasma reaction between tetraethoxysilane and oxygen.

  Silicon oxide is obtained, for example, by applying a liquid raw material containing inorganic polysilazane, inorganic siloxane or the like on a substrate using a spin coating method and performing a thermosetting reaction in a furnace body or the like.

  Examples of the method for producing polysilicon include a low pressure CVD method in which monosilane is thermally reacted, a plasma CVD method in which monosilane is subjected to plasma reaction, and the like.

  As a method for producing silicon nitride, for example, a low pressure CVD method in which dichlorosilane and ammonia are thermally reacted, a plasma CVD method in which monosilane, ammonia and nitrogen are subjected to plasma reaction, and the like can be given. The silicon nitride obtained by the above method may contain elements other than silicon and nitrogen, such as carbon and hydrogen, in order to adjust the material.

  In order to stabilize materials such as silicon oxide, polysilicon, and silicon nitride obtained by the above method, heat treatment may be performed at a temperature of 200 to 1000 ° C. as necessary. Further, the silicon oxide obtained by the above method may contain a small amount of boron (B), phosphorus (P), carbon (C) or the like in order to improve the embedding property.

  Hereinafter, the polishing method according to this embodiment will be described by taking a polishing method of a semiconductor substrate on which an insulating material is formed as an example. In the polishing method according to the present embodiment, as a polishing apparatus, a general polishing apparatus having a holder capable of holding a substrate such as a semiconductor substrate having a surface to be polished and a polishing surface plate to which a polishing pad can be attached. Can be used. Each of the holder and the polishing surface plate is provided with a motor capable of changing the rotation speed. As a polishing apparatus, for example, a polishing apparatus: MIRRA 3400 manufactured by APPLIED MATERIALS can be used.

  As the polishing pad, a general nonwoven fabric, foam, non-foam, or the like can be used. As a material of the polishing pad, polyurethane, acrylic, polyester, acrylic-ester copolymer, polytetrafluoroethylene, polypropylene, polyethylene, poly-4-methylpentene, cellulose, cellulose ester, polyamide (for example, nylon (registered trademark) and Aramid), polyimide, polyimide amide, polysiloxane copolymer, oxirane compound, phenol resin, polystyrene, polycarbonate, epoxy resin and the like can be used. As the material of the polishing pad, in particular, foamed polyurethane and non-foamed polyurethane are preferable from the viewpoint of polishing speed and flatness. It is preferable that the polishing pad is grooved so as to collect the abrasive.

Although there is no limitation on the polishing conditions, the rotation speed of the polishing platen is preferably 200 min ⁻¹ or less so that the semiconductor substrate does not pop out, and the polishing pressure (processing load) applied to the semiconductor substrate is such that polishing flaws occur. From the viewpoint of sufficient suppression, 300 kPa or less is preferable. During polishing, it is preferable to continuously supply the polishing agent to the polishing pad with a pump or the like. Although there is no restriction | limiting in this supply amount, it is preferable that the surface of a polishing pad is always covered with the abrasive | polishing agent.

  The semiconductor substrate after the polishing is preferably washed well under running water to remove particles adhering to the substrate. For cleaning, dilute hydrofluoric acid or ammonia water may be used in addition to pure water, and a brush may be used in combination to increase cleaning efficiency. Further, after cleaning, it is preferable to dry the semiconductor substrate after water droplets adhering to the semiconductor substrate are removed using a spin dryer or the like.

  The abrasive | polishing agent, abrasive | polishing agent set, and grinding | polishing method which concern on this embodiment can be used also for grinding | polishing of a premetal insulating material. As the premetal insulating material, for example, phosphorus-silicate glass and boron-phosphorus-silicate glass are used in addition to silicon oxide, and silicon oxyfluoride, fluorinated amorphous carbon, and the like can also be used.

  The abrasive | polishing agent, abrasive | polishing agent set, and grinding | polishing method which concern on this embodiment are applicable also to materials other than insulating materials, such as a silicon oxide. Examples of such materials include high dielectric constant materials such as Hf-based, Ti-based, and Ta-based oxides; semiconductor materials such as silicon, amorphous silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, and organic semiconductors; GeSbTe Inorganic conductive materials such as ITO; Polymer resins such as polyimides, polybenzoxazoles, acrylics, epoxies, and phenols.

  The polishing agent, the polishing agent set, and the polishing method according to the present embodiment are not only film-like objects to be polished, but also various types composed of glass, silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, sapphire, plastic, or the like. It can also be applied to substrates.

  The polishing agent, the polishing agent set, and the polishing method according to the present embodiment are not only for manufacturing semiconductor elements, but also for image display devices such as TFTs and organic ELs; optical parts such as photomasks, lenses, prisms, optical fibers, and single crystal scintillators Optical elements such as optical switching elements and optical waveguides; light emitting elements such as solid lasers and blue laser LEDs; and magnetic storage devices such as magnetic disks and magnetic heads.

  Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

<Single-crystal cerium oxide treated with anion dispersion>
Hereinafter, as the single crystal cerium oxide of the example, diluted polishing liquid A obtained by diluting cerium oxide (product name: HC60 (2-), cerium oxide: 30% by mass) manufactured by RHODIA OPERATIONS to 10% by mass is used. I went.

(Confirmation of crystallite)
Using a scanning electron microscope (SEM), when the dried powder of HC60 (2-) manufactured by RHODIA OPERATIONS was observed, the primary particle diameter was about 40 nm to about 300 nm, and the cerium oxide particles of 40 nm to 160 nm were entirely present. It was 99% or more. Further, cerium oxide particles of 10 nm or less or 500 nm or more, which are recognized in cerium oxide produced by a pulverization method, were not recognized, and the crystallite size distribution was narrow. Further, no grain boundary was observed, and it was a single crystal cerium oxide.

(Measurement of average particle size)
The average particle diameter of HC60 (2-) manufactured by RHODIA OPERATIONS was measured using a product name manufactured by HORIBA, Ltd., trade name: LA-920, and found to be 103.5 nm.

  The measuring method is as follows. First, an HC60 (2-) diluted solution diluted to 4.0% by mass was prepared. Measurement was performed by adding 118 g of ultrapure water as a dispersion medium and 138 μl of the HC60 (2-) diluted solution, and the value displayed as the median diameter was read.

(Abrasive surface potential)
When the surface potential of HC60 (2-) manufactured by RHODIA OPERATIONS was measured using a product name: Delsa NanoC manufactured by Beckman Coulter, it was about -50 mV.

  The measuring method is as follows. First, an HC60 (2-) diluted solution diluted to 0.002% by mass was prepared. The HC60 (2-) diluted solution was put into a cell and set in an apparatus for measurement, and an average value displayed by three consecutive measurements was read.

<Preparation of CMP abrasive>
[Example 1]
D-glucose 10.0% by mass (molecular weight: 180), surfactant A (polyethoxylate of 2,4,7,9-tetramethyl-5-decyne-4,7-diol) 1.0% by mass, By mixing 100 g of an additive liquid storage solution containing acetic acid 0.08 mass%, imidazole 0.1 mass% and water 88.82 mass%, diluted polishing liquid A 67 g, and pure water 833 g, the cerium oxide particles are mixed. A CMP abrasive having a pH of 6.1 containing 0.67% by mass, glucose 1.0% by mass, surfactant A 0.1% by mass, and acetic acid 0.008% by mass was prepared.

[Example 2]
Except for changing the saccharide, the same procedure as in Example 1 was performed, except that cerium oxide particles were 0.67% by mass, fructose (molecular weight: 182) was 1.0% by mass, surfactant A was 0.1% by mass, and acetic acid was added. A CMP abrasive having a pH of 6.0 and containing 0.008% by mass was prepared.

[Example 3]
Except for changing the saccharide, the same procedure as in Example 1 was performed, except that cerium oxide particles were 0.67% by mass, sucrose (molecular weight: 342) was 1.0% by mass, surfactant A was 0.1% by mass, and acetic acid was added. A CMP abrasive having a pH of 6.0 and containing 0.008% by mass was prepared.

[Example 4]
Except for changing the saccharide, the same procedure as in Example 1 was performed, except that cerium oxide particles were 0.67% by mass, maltose (molecular weight: 342) was 1.0% by mass, surfactant A was 0.1% by mass, and acetic acid was added. A CMP abrasive having a pH of 6.0 and containing 0.008% by mass was prepared.

[Example 5]
Except for changing the saccharide, in the same manner as in Example 1, 0.67% by mass of cerium oxide particles, dextrin (manufactured by Sanwa Starch Co., Ltd .: Sandeck # 300, molecular weight: 4000, “Sandeck” is a registered trademark) A CMP abrasive having a pH of 6.0 containing 1.0% by mass, 0.1% by mass of surfactant A and 0.008% by mass of acetic acid was prepared.

[Example 6]
Except for changing the surfactant, the same procedure as in Example 1 was performed, except that cerium oxide particles were 0.67% by mass, glucose (molecular weight: 182) was 1.0% by mass, and surfactant B (polyoxyethylene styrenated phenyl) was used. A CMP abrasive having a pH of 6.1 containing 0.1% by mass of ether and 0.008% by mass of acetic acid was prepared.

[Example 7]
Except for changing the organic acid, the same procedure as in Example 1 was carried out, except that cerium oxide particles were 0.67% by mass, glucose (molecular weight: 182) was 1.0% by mass, surfactant A was 0.1% by mass, and propion. A CMP abrasive having a pH of 6.6 containing 0.008% by mass of acid was prepared.

[Comparative Example 1]
Polyacrylic acid 1.0% by mass (molecular weight: 4000), surfactant A (polyethoxylate of 2,4,7,9-tetramethyl-5-decyne-4,7-diol) 0.8% by mass, By mixing 100 g of an additive liquid storage solution containing 0.08% by mass of acetic acid, 0.28% by mass of 25% aqueous ammonia and 97.84% by mass of water, 67 g of diluted polishing liquid A, and 833 g of pure water, -Free CMP polishing at pH 5.2, containing 0.67% by mass of cerium oxide particles, 0.1% by mass of polyacrylic acid, 0.08% by mass of surfactant A, and 0.008% by mass of acetic acid An agent was prepared.

[Comparative Example 2]
CMP polishing at pH 6.0 containing 0.67% by mass of cerium oxide particles, 0.1% by mass of surfactant A and 0.008% by mass of acetic acid, as in Example 1 except that no saccharide was contained. An agent was prepared.

[Comparative Example 3]
PH 6 containing 0.67% by mass of cerium oxide particles, 1.0% by mass of glucose (molecular weight: 182), and 0.008% by mass of acetic acid in the same manner as in Example 1 except that the surfactant is not included. A zero CMP abrasive was prepared.

[Comparative Example 4]
Except for not containing an organic acid, the same procedure as in Example 1 was carried out, containing cerium oxide particles at 0.67% by mass, glucose (molecular weight: 182) at 1.0% by mass, and surfactant A at 0.1% by mass. A CMP abrasive having a pH of 6.0 was prepared.

<Liquid property evaluation>
The pH of the CMP abrasive and the average particle diameter of cerium oxide in the CMP abrasive were evaluated under the following conditions.

(Surface potential of abrasive grains in polishing liquid)
When the surface potential of the abrasive grains contained in the polishing liquid was measured using a product name: Delsa NanoC manufactured by Beckman Coulter, it was in the range of about -250 to -5 mV.

(PH)
Measurement temperature: 25 ± 5 ° C
Measuring device: manufactured by HORIBA, Ltd., model number F-51
Measurement method: standard buffer (phthalate pH buffer, pH: 4.01 (25 ° C.); neutral phosphate pH buffer, pH 6.86 (25 ° C.); borate pH buffer, pH 9. 18 (25 ° C.) was used to calibrate the three points, and then the electrode was put in a CMP abrasive and the pH after being stabilized after 2 minutes or more was measured with the measuring device.

(Average particle size)
The average particle diameter of the cerium oxide particles in the CMP abrasive was measured using a product name: LA-920, manufactured by HORIBA, Ltd. The measuring method is as follows. Measurement was performed by adding 118.0 g of ultrapure water as a dispersion medium and 824 μl of CMP abrasive, and the value displayed as the median diameter was read.

<CMP evaluation>
The substrate to be polished was polished under the following polishing conditions using a CMP abrasive.

(CMP polishing conditions)
Polishing device: MIRRA 3400 (Applied Materials)
・ CMP abrasive flow rate: 200 mL / min ・ Polished substrate:
(Unpatterned wafer)
As a blanket wafer on which no pattern was formed, a substrate in which a silicon oxide film having a thickness of 1 μm was formed on a silicon substrate by a plasma CVD method was used.
(Pattern wafer)
An 864 wafer (trade name, diameter: 200 mm) manufactured by SEMATECH was used as a pattern wafer on which a simulated pattern was formed. In the patterned wafer, after a polysilicon film is stacked on the silicon substrate as a stopper film, a trench is formed in an exposure process, and a silicon oxide as an insulating film is formed on the silicon substrate and the polysilicon film so as to fill the polysilicon film and the trench. It was a wafer obtained by laminating a film (SiO ₂ film). The silicon oxide film was formed by the HDP (High Density Plasma) method.
Polishing pad: foamed polyurethane resin with closed cells (Rohm and Haas Japan, model number IC1010), Shore D hardness: 60
Polishing pressure: 21.0 kPa (3.0 psi)
-Relative speed between substrate and polishing platen: 85 m / min-Polishing time: Blanket wafer was polished for 1 minute. The pattern wafer was polished until the polysilicon film as a stopper film was exposed. Further, the progress of dishing was confirmed by further grinding for the same time as the polishing time taken until the polysilicon film was exposed.
-Cleaning: After CMP treatment, cleaning with ultrasonic water was performed, followed by drying with a spin dryer.

  As the pattern wafer, a wafer having a line and space of 100 μm pitch and a convex pattern density (area) of 20%, 50%, and 80% was used. The pattern wafer has a pattern in which active parts (convex parts) masked with a polysilicon film and trench parts (concave parts) in which grooves are formed are alternately arranged as a simulated pattern. For example, “the line and space has a pitch of 100 μm” means that the total width of the line portion and the space portion is 100 μm. For example, “the line and space is 100 μm pitch and the convex pattern density is 20%” means a pattern in which convex portions having a convex portion width of 20 μm and concave portions having a width of 80 μm are alternately arranged.

  In the pattern wafer, the thickness of the silicon oxide film was 600 nm on both the silicon substrate and the polysilicon film. Specifically, as shown in FIG. 1, the thickness of the polysilicon film 2 on the silicon substrate 1 is 150 nm, the thickness of the convex portion of the silicon oxide film 3 is 600 nm, and the concave portion of the silicon oxide film 3 is formed. The thickness of the concave portion of the silicon oxide film 3 was 500 nm (trench depth 350 nm + polysilicon film thickness 150 nm).

  When polishing the pattern wafer, the silicon oxide film 3 shown in FIG. 1 has a film thickness of about 100 μm and a 50% density pattern by polishing the wafer using a known CMP abrasive (fumed silica). A wafer in a state of 250 nm was used. Specifically, a wafer polished for 55 seconds using an abrasive prepared by mixing SS-25 manufactured by Cabot Corporation and pure water at a ratio of 1: 1 was used.

<Polished product evaluation>
[Blanket wafer polishing speed]
The polishing rate (silicon oxide polishing rate: SiO ₂ RR) of the film to be polished (silicon oxide film) polished and cleaned under the above conditions was obtained from the following equation. In addition, the film thickness difference of the film to be polished before and after polishing was determined using an optical interference film thickness apparatus (manufactured by Filmetrics, trade name: F80).
(Polishing rate: RR) = (Thickness difference of the film to be polished before and after polishing (nm)) / (Polishing time (min))

[Pattern wafer evaluation]
By measuring the remaining film thickness of the polysilicon film or silicon oxide film on the convex part of the patterned wafer polished and cleaned under the above conditions and the residual film thickness of the silicon oxide film in the concave part, the amount of remaining step (dishing) is obtained from the following equation: Asked. The film thickness of the film to be polished before and after polishing was determined using an optical interference film thickness apparatus (manufactured by Nanometrics, trade name: Nanospec AFT-5100).
Residual step (dishing) = (350 + polysilicon film thickness (nm)) − (residual film thickness of recessed silicon oxide film (nm))

[Polishing scratch evaluation]
The substrate to be polished (blanket wafer substrate having a silicon oxide film) polished and cleaned under the above conditions was immersed in an aqueous solution of 0.5% by mass of hydrogen fluoride for 15 seconds, and then washed with water for 60 seconds. Subsequently, the surface of the film to be polished was washed for 1 minute while supplying water using a polyvinyl alcohol brush, and then dried. A defect of 0.2 μm or more on the surface of the film to be polished was detected using Complis made by APPLIED MATERIALS. Further, when the surface of the film to be polished was observed using the defect detection coordinates obtained by Complus and SEM Vision made by APPLIED MATERIALS, the number of polishing scratches of 0.2 μm or more on the surface of the film to be polished was In any of the comparative examples, it was about 0 to 10 (pieces / wafer), and the generation of polishing scratches was sufficiently suppressed.

  Note that for the portion where the silicon oxide film could not be removed and the polysilicon film was not exposed, the film thickness of the silicon oxide remaining in the portion was measured (in the table, the number with * indicates the remaining silicon oxide film) Indicates thickness). In this case, the difference in the polysilicon film thickness is not measured.

  Tables 1 and 2 show the measurement results obtained in Examples 1 to 7 and Comparative Examples 1 to 4, respectively.

  Hereinafter, the results shown in Tables 1 and 2 will be described in detail.

  In Example 1, the p-Si film thickness of the 20% to 80% density part is 148 nm or more, and polishing of the p-Si film is suppressed as compared with the comparative example. Further, the remaining steps were 19 nm (20% density part), 3 nm (50% density part), and 0 nm (80% density part), respectively, and a result in which dishing was suppressed from the comparative example was obtained.

  In Example 2, the p-Si film thickness of the 20% to 80% density part is 148 nm or more, and polishing of the p-Si film is suppressed as compared with the comparative example. Further, the remaining steps were 18 nm (20% density part), 4 nm (50% density part), and 0 nm (80% density part), respectively, and a result in which dishing was suppressed from the comparative example was obtained.

  In Example 3, the p-Si film thickness of the 20% to 80% density part is 148 nm or more, and polishing of the p-Si film is suppressed as compared with the comparative example. Further, the remaining steps were 18 nm (20% density part), 4 nm (50% density part), and 0 nm (80% density part), respectively, and a result in which dishing was suppressed from the comparative example was obtained.

  In Example 4, the p-Si film thickness of the 20% to 80% density part is 148 nm or more, and polishing of the p-Si film is suppressed as compared with the comparative example. Further, the remaining steps were 13 nm (20% density part), 3 nm (50% density part), and 0 nm (80% density part), respectively, and a result in which dishing was suppressed from the comparative example was obtained.

  In Example 5, the p-Si film thickness of the 20% to 80% density part is 146 nm or more, and polishing of the p-Si film is suppressed as compared with the comparative example. Further, the remaining steps were 36 nm (20% density part), 8 nm (50% density part), and 0 nm (80% density part), respectively, and a result in which dishing was suppressed from the comparative example was obtained.

  In Example 6, the p-Si film thickness of the 20% to 80% density part is 146 nm or more, and polishing of the p-Si film is suppressed as compared with the comparative example. Further, the remaining steps were 16 nm (20% density part), 2 nm (50% density part), and 0 nm (80% density part), respectively, and a result in which dishing was suppressed from the comparative example was obtained.

  In Example 7, the p-Si film thickness of the 20% to 80% density part is 148 nm or more, and polishing of the p-Si film is suppressed as compared with the comparative example. Further, the remaining steps were 28 nm (20% density part), 2 nm (50% density part), and 0 nm (80% density part), respectively, and a result in which dishing was suppressed from the comparative example was obtained.

In Comparative Example 1, the SiO ₂ RR was 53 nm / min. Further, in the pattern wafer evaluation, the silicon oxide film on the convex portion could not be removed in 190 seconds.

  In Comparative Example 2, the p-Si film thickness of the 20% to 80% density part is 140 nm or more, and polishing of the p-Si film is suppressed as much as in the example. The remaining steps were 160 nm (20% density part), 77 nm (50% density part), and 23 nm (80% density part), respectively.

  In Comparative Example 3, the p-Si film thicknesses of the 20% to 80% density part were 100 nm (20% density part), 148 nm (50% density part), and 148 nm (80% density part), respectively. The remaining steps are 10 nm (20% density part), 6 nm (50% density part), and 0 nm (80% density part), respectively, but the 20% density p-Si is greatly polished.

In Comparative Example 4, the SiO ₂ RR was 180 nm / min. Further, in the pattern wafer evaluation, the silicon oxide film on the convex portion could not be removed in 190 seconds.

  According to the present invention, it is possible to provide a polishing agent, a polishing agent set, and a polishing method capable of suppressing generation of polishing flaws while improving flatness on a surface to be polished and polishing selectivity of an insulating material with respect to a stopper material. . Further, according to the present invention, in particular, in CMP technology for flattening an STI insulating material, a premetal insulating material, an interlayer insulating material, etc., polishing capable of obtaining a high level of flatness while suppressing generation of polishing flaws. An abrasive, an abrasive set and a polishing method can be provided.

  DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 2 ... Polysilicon film, 3 ... Silicon oxide film.

Claims (16)

  An abrasive containing water, cerium oxide particles, a saccharide having 140 or less carbon atoms, a nonionic surfactant, and an organic acid, wherein the cerium oxide particles are single crystal particles, An abrasive having a negative surface potential in the abrasive.   The abrasive | polishing agent of Claim 1 whose primary particle diameters of an abrasive grain are 1 nm or more and 300 nm or less.   The abrasive | polishing agent of Claim 1 whose primary particle diameter of an abrasive grain is 1 nm or more and 300 nm or less, and whose primary particle diameter of 160 nm or less is 90% or more of the whole.   The abrasive | polishing agent of Claim 1 whose primary particle diameter of an abrasive grain is 1 nm or more and 300 nm or less, and whose primary particle diameter of 160 nm or less is 99% or more of the whole.   The abrasive | polishing agent as described in any one of Claims 1-4 whose saccharide | sugar does not contain a carboxyl group.   The abrasive | polishing agent as described in any one of Claims 1-5 whose content of saccharides is 0.1 mass% or more on the basis of the total mass of an abrasive | polishing agent.   The abrasive | polishing agent as described in any one of Claims 1-6 whose content of a nonionic surfactant is 0.01 mass% or more on the basis of the total mass of an abrasive | polishing agent.   The abrasive | polishing agent as described in any one of Claims 1-7 whose organic acid is C4 or less monocarboxylic acid.   The abrasive | polishing agent as described in any one of Claims 1-8 whose content of an abrasive grain is 0.1 to 5 mass% on the basis of the total mass of an abrasive | polishing agent.   The abrasive | polishing agent as described in any one of Claims 1-9 whose pH is 4.0 or more and 7.0 or less.   The abrasive | polishing agent as described in any one of Claims 1-10 used in order to grind | polish the to-be-polished surface containing a silicon oxide.   The constituents of the abrasive according to any one of claims 1 to 11 are stored separately in a plurality of liquids, the first liquid contains abrasive grains, and the second liquid is a saccharide, a surfactant and an organic substance. An abrasive set comprising at least one selected from the group consisting of acids.   A method for polishing a substrate, comprising a step of polishing a surface to be polished of the substrate using the abrasive according to any one of claims 1 to 11.   A method for polishing a substrate, comprising a step of polishing a surface to be polished of a substrate using an abrasive obtained by mixing the first liquid and the second liquid in the abrasive set according to claim 12.   A method for polishing a substrate having an insulating material and polysilicon, comprising: selectively polishing the insulating material with respect to the polysilicon using the abrasive according to any one of claims 1 to 11. A method for polishing a substrate.   A method for polishing a substrate having an insulating material and polysilicon, wherein the insulating material is formed using an abrasive obtained by mixing a first liquid and a second liquid in the abrasive set according to claim 12. A method for polishing a substrate comprising a step of selectively polishing polysilicon.

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