Cerium oxide particles, method for their production and their use in chemical mechanical polishing

Abstract

The invention relates to ceria particles having a roughness index RI of at least 5, a method for their manufacture, and their use in chemical mechanical polishing applications.

Description

[0001] This invention is a divisional application. The original application was filed on March 10, 2022, with application number 202280021012.5, and the invention title was "Cerium oxide particles, their manufacturing method and their use in chemical mechanical polishing". Technical Field

[0002] This invention relates to cerium oxide particles and their use as components in compositions for grinding, particularly chemical mechanical grinding (CMP) compositions. The invention also relates to methods for preparing these cerium oxide particles.

[0003] More specifically, the present invention provides cerium oxide particles that exhibit good grinding properties when applied in chemical mechanical grinding compositions; and a simple, economical, and easily implemented method for preparing such particles on an industrial scale. Background Technology

[0004] Cerium dioxide is commonly used in polishing applications. The development of the electronics industry demands a growing and substantial use of compositions for polishing various components, such as disks or dielectric compounds. These compositions, typically commercialized as dispersions, must exhibit a number of characteristics. For example, they must provide a high degree of material removal, reflecting their polishing power. They must also have the lowest possible defectivity; the term "defectivity" specifically refers to the number of scratches exhibited on a substrate once treated with the composition. For stability and ease of use, these dispersions typically contain submicron-sized particles (i.e., generally less than 300 nm). Furthermore, the presence of particles that are too fine in these dispersions reduces their polishing power, while particles that are too large can increase defectivity.

[0005] Therefore, several types of cerium oxide particles specifically designed for chemical mechanical grinding applications are known in the prior art.

[0006] WO 2015 / 197656 discloses cerium oxide particles doped with metals.

[0007] WO 08043703 discloses a suspension of cerium oxide particles in a liquid phase, the particles being secondary particles having an average size of up to 200 nm, and the secondary particles comprising primary particles having an average size of up to 100 nm, wherein the standard deviation is up to 30% of the average size value of the primary particles.

[0008] WO 2015 / 091495 discloses a suspension of cerium oxide particles in a liquid phase, wherein the particles comprise secondary particles containing primary particles, wherein the secondary particles have an average size D50 between 105 and 1000 nm, wherein the standard deviation is between 10% and 50% of the average size value of the secondary particles; and the primary particles have an average size D50 between 100 and 300 nm, wherein the standard deviation is between 10% and 30% of the average size value of the primary particles.

[0009] We believe there is still room for improvement in providing new cerium oxide particles that exhibit improved performance in chemical mechanical grinding, as well as simple, economical, and easily implementable methods for preparing such particles on an industrial scale. Summary of the Invention

[0010] The applicant has refined new cerium oxide particles that can solve the above problems.

[0011] Therefore, one subject of the present invention is cerium oxide particles exhibiting a roughness index (RI) of at least 5, particularly ranging from 5 to 20, and particularly ranging from 6 to 17. More particularly, the roughness index of the particles is defined by the following formula: Wherein “TEM size” refers to the average size of the particles measured on a transmission electron microscope (TEM) image. Preferably, to obtain this average size, at least 80 particles are measured on the transmission electron microscope image.

[0012] "SSA size" refers to the theoretical average size of a particle, determined by its BET (Brunauer, Emmett, and Teller) specific surface area. More specifically, it can be calculated using the following formula: Where SSA represents the BET specific surface area of ​​these particles, and ρ represents the density of cerium oxide (IV) which is equal to 7.22 g / cm³. 3 More specifically, the BET surface area can be determined by nitrogen adsorption.

[0013] To the best of the inventors' knowledge, the particles of the present invention achieve a roughness index higher than that of cerium oxide particles in the prior art. It is believed that when such particles are used as abrasive particles in chemical mechanical polishing compositions or methods, they contribute to achieving higher polishing efficiency.

[0014] The present invention also relates to a method for manufacturing the cerium oxide particles of the present invention, the method comprising at least the following steps: (a) Under an inert atmosphere, (i) an aqueous solution of a base, (ii) containing NO3 - Ce III Optional Ce IV (iii) contacting an aqueous solution of an organic acid or a salt thereof to obtain a mixture, wherein the organic acid is a substituted or unsubstituted C1-C20-alkyl, alkenyl or alkynyl carboxylic acid; (b) subjecting the mixture obtained in step (a) to heat treatment; (c) Optionally, acidify the mixture obtained in step (b); (d) Optionally, wash the solid material obtained at the end of step (b) or (c) with water; (e) Optionally, the solid material obtained at the end of step (d) may be subjected to mechanical treatment to deagglomerate the particles.

[0015] Advantageously, this method enables the preparation of the cerium oxide particles of the present invention in a simple manner.

[0016] The present invention also relates to cerium oxide particles that can be obtained or obtained by the above methods, a dispersion of the cerium oxide particles of the present invention in a liquid medium, the use of the dispersion or the particles of the present invention in preparing a chemimechanical polishing composition, a chemimechanical polishing composition comprising the dispersion or the particles, a polishing method wherein the chemimechanical polishing composition is used to remove a portion of a substrate, and a semiconductor comprising a substrate thus polished. Attached Figure Description

[0017] Figures 1 to 4 This is an image of the particles of the present invention observed by a transmission electron microscope.

[0018] Figure 5 These are images of cerium oxide particles observed using a transmission electron microscope, employing existing technology.

[0019] These images were obtained using a JEM-1400 (Japan Electronics Corporation (JEOL)) device operating at 120 kV. Detailed Implementation

[0020] In this disclosure, expressions such as "included between" should be understood as including limit values.

[0021] The term "cerium oxide" in relation to the particles of this invention refers to cerium oxide (IV), also known as cerium dioxide. Cerium oxide generally has a purity of at least 99.8% by weight relative to the oxide. Cerium oxide is generally crystalline cerium dioxide. Certain impurities other than cerium may be present in the oxide. These impurities may originate from the raw materials or starting materials used in the method for preparing cerium oxide. The total proportion of these impurities is generally less than 0.2% by weight relative to cerium oxide. In this application, residual nitrates are not considered impurities.

[0022] The term "dispersion" in relation to the dispersion of cerium oxide particles in this invention refers to a system consisting of submicron-sized solid fine cerium oxide particles stably dispersed in a liquid medium, the particles possibly also optionally containing residual amounts of bound or adsorbed ions, such as nitrate or ammonium ions.

[0023] The invention will now be described in more detail according to different embodiments thereof.

[0024] As explained above, one subject of the present invention is cerium oxide particles that exhibit a roughness index (RI) of at least 5. More particularly, the roughness index of the particles of the present invention can be in the range of 5 to 20, particularly from 6 to 17, and even more particularly from 7 to 14.

[0025] The roughness index (RI) of a particle is defined by the following formula: Here, "TEM size" represents the average size of these particles measured in transmission electron microscopy images, and "SSA size" represents the theoretical average size of these particles determined by their BET (Brunauer, Emmett, and Teller) specific surface areas. Specifically, the SSA size can be calculated using the following formula: Where SSA represents the BET specific surface area of ​​these particles, and ρ represents the density of cerium oxide (IV) which is equal to 7.22 g / cm³. 3 In particular, the size of the SSA can be determined by nitrogen adsorption.

[0026] TEM size is the effective average size of the particles. Measurements are preferably performed on a large number of particles, for example, at least 80, preferably at least 90, more preferably at least 100, to obtain statistical analysis. Measurements are typically performed on one or more photographs of the same sample of cerium oxide particles. The particles retained are preferably such that their images are clearly visible on one or more photographs. According to an embodiment detailed later, the number of spherical particles preferably corresponds to at least 80.0%, more particularly at least 90.0%, and even more particularly at least 95.0% of the particles.

[0027] Specific surface area (SSA) can be determined by the Brunauer-Emmett-Teller method (BET method) via nitrogen adsorption onto a powder of cerium oxide particles. This method is disclosed in standard ASTM D 3663-03 (re-approved in 2015). It is also described in the journal *The Journal of the American Chemical Society*, 60, 309 (1938). SSA can be determined automatically using the Micromeritics TriStar 3000 apparatus, following the manufacturer's instructions. Prior to measurement, the powdered sample is degassed in static air by heating at a temperature of up to 210°C to remove adsorbed material.

[0028] The BET specific surface area determination allows for the calculation of the SSA size using the formula given above: for a given SSA, this formula provides the theoretical size of the cerium oxide (IV) particles, assuming the particles are spherical. Therefore, the ratio of TEM size to SSA size is an indicator of particle roughness: the higher the ratio, the higher the particle roughness. It is believed that cerium oxide particles with an increased roughness index have improved efficiency when used in grinding methods such as chemical mechanical polishing.

[0029] According to a preferred embodiment, the cerium oxide particles of the present invention are spherical in shape. To the inventors' knowledge, the combination of a specific roughness index and a specific spherical morphology of the particles contributes to enhanced results in chemical mechanical polishing using them, compared to conventional cerium oxide particles (i.e., non-spherical and not exhibiting the desired roughness index).

[0030] The spherical cerium oxide particles of the present invention can exhibit a sphericity ratio SR between 0.8 and 1.0, more particularly between 0.85 and 1.0, and even more particularly between 0.90 and 1.0. SR can preferably be between 0.90 and 1.0, or between 0.95 and 1.0. The sphericity ratio of the particles is calculated from the perimeter P and area A of the measured particle projection using the following equation: For an ideal sphere, SR is 1.0, and for spherical particles it is less than 1.0.

[0031] Sphericity ratio is typically determined by dynamic image analysis (DIA). Examples of devices that can be used to perform DIA include Retsch's CAMSIZER® P4 or Sympatec's QicPic®.

[0032] Sphericity ratio can be measured more specifically according to ISO 13322-2 (2006). DIA typically requires statistically significant analysis of a large number of particles (e.g., at least 80).

[0033] According to one embodiment, the cerium oxide particles of the present invention can exhibit an average size greater than or equal to 30 nm. Typically, the particle size is greater than or equal to 70 nm. The cerium oxide particles of the present invention can exhibit an average size less than or equal to 500 nm. Typically, the particle size is less than or equal to 300 nm, particularly less than or equal to 150 nm. In one aspect, the cerium oxide particles of the present invention can exhibit an average size including between 140 and 300 nm, particularly between 145 and 270 nm, more particularly between 150 and 250 nm, and even more particularly between 155 and 240 nm. The average size is preferably measured by TEM imaging. The measurement is preferably performed on at least 80 particles.

[0034] According to one embodiment, the cerium oxide particles of the present invention can exhibit a specific surface area between 30 and 100 m² / g, more particularly between 32 and 80 m² / g, more particularly between 35 and 70 m² / g, and even more particularly between 36 and 60 m² / g. As explained above, the specific surface area is determined by nitrogen adsorption onto the powder using the Bruno-Emmett-Teller method (BET method).

[0035] Specifically, the specific surface area ranges from 15 to 100 m² / g, and more specifically between 20 and 40 m² / g. In another aspect, the present invention relates to cerium oxide particles, characterized in that the particles are spherical and exhibit a roughness index RI of at least 2, particularly at least 3.5, wherein RI is defined by the following formula: Where “TEM size” represents the average size of the particle measured on a transmission electron microscope image, and “SSA size” represents the theoretical average size of the particle according to the following formula: Wherein SSA represents the BET specific surface area of ​​the particles as determined by nitrogen adsorption, and ρ represents the density of cerium oxide (IV) which is equal to 7.22 g / cm3, and the particles exhibit a carbon weight ratio ranging from 0.001 wt% to 5 wt%, particularly from 0.1 wt% to 2.5 wt%.

[0036] In a specific embodiment, the roughness index RI in this aspect is less than 5.

[0037] As the inventors know, the carbon weight ratio in the cerium oxide particles according to this aspect contributes to the compatibility of the cerium oxide particles with other components of dispersions and grinding compositions commonly used in chemical mechanical grinding applications.

[0038] The spherical shape, particle size, and specific surface area of ​​this aspect are characterized as described above.

[0039] According to one embodiment, the cerium oxide particles of the present invention can exhibit a carbon weight ratio ranging from 0.001 wt% to 5 wt%, particularly from 0.1 wt% to 2.5 wt%. Trace carbon levels can be a footprint of the synthetic method used to prepare the particles, which requires specific organic acids. The dosage of elemental carbon can be determined using a carbon and sulfur analyzer such as a Horiba EMIA 320-V2.

[0040] The present invention also relates to a method for manufacturing the cerium oxide particles of the present invention, the method comprising at least the following steps: (a) Under an inert atmosphere, (i) an aqueous solution of a base, (ii) containing NO3 - Ce III Optional Ce IV (iii) contacting an aqueous solution of an organic acid or a salt thereof to obtain a mixture, wherein the organic acid is a substituted or unsubstituted C1-C20-alkyl, alkenyl or alkynyl carboxylic acid; (b) subjecting the mixture obtained in step (a) to heat treatment; (c) Optionally, acidify the mixture obtained in step (b); (d) Optionally, wash the solid material obtained at the end of step (b) or (c) with water; (e) Optionally, the solid material obtained at the end of step (d) may be subjected to mechanical treatment to deagglomerate the particles.

[0041] Advantageously, high-purity salts and ingredients are used. The purity of these salts can be at least 99.5 wt%, more specifically at least 99.9 wt%.

[0042] In step (a), an aqueous solution of a base is used (i). Hydroxide-type products can be particularly used as the base. Alkali metal hydroxides or alkaline earth metal hydroxides and ammonia may be mentioned. Secondary amines, tertiary amines, or quaternary amines may also be used. The aqueous solution of the base may also be pre-degassed by bubbling with an inert gas.

[0043] The amount of base used in step (a) (expressed as molar base / total Ce) is preferably between 4 and 10, and more preferably between 5 and 8.

[0044] In step (a), NO3 is used - Ce III and optional Ce IV (ii) Aqueous solutions. Nitrates or cerium can be used specifically to prepare solutions. If Ce IV If it exists in aqueous solution, then Ce IV The total Ce molar ratio is preferably between 1 / 500,000 and 1 / 4,000. This molar ratio can be particularly between 1 / 6,000 and 1 / 4,000. The Ce used in the examples can be used. IV / Total Ce molar ratio.

[0045] An aqueous solution of cerium nitrate obtained by the reaction of nitric acid with hydrated cerium oxide can be used in the preparation method. Cerium oxide is conventionally prepared by reacting a cerium salt solution with an aqueous ammonia solution in the presence of aqueous hydrogen peroxide to remove Ce. III Cations are converted to Ce IV It is prepared by using cations. It is also particularly advantageous to use a cerium nitrate solution obtained by electrolytic oxidation of a cerium nitrate solution as disclosed in FR 2570087. The cerium nitrate solution obtained according to the teachings of FR 2570087 can exhibit an acidity of about 0.6 N.

[0046] Ce IV It can be provided by a salt (if present in step (a)), which can be cerium IV nitrate or cerium ammonium nitrate.

[0047] The amount of nitrate ions in the aqueous solution used in step (a) (as NO3) - / Ce III (Molar ratio expressed) is typically between 1 / 3 and 5 / 1. The acidity of the aqueous solution used in step (a) is preferably between 0.8 N and 12.0 N.

[0048] In step (a), a specific organic acid (iii) is used, which is a substituted or unsubstituted C1-C20 -alkyl, -alken, or -alkynyl carboxylic acid or a salt thereof. The chain length of the -alkyl, -alken, or -alkynyl group may particularly be in the C1-C12, C1-C6, or even C1-C3 range. The organic acid is preferably an -alkyl or -alkenyl carboxylic acid, more preferably an -alkyl carboxylic acid.

[0049] According to one embodiment, the organic acid is substituted. Examples of substituents include halogens, lower alkyl groups (i.e., alkyl groups having fewer than six carbon atoms), aryl groups, alkoxy groups, hydroxyl groups, amino groups, alkylamino groups, arylamino groups, alkylsulfinyl groups, alkylsulfonyl groups, arylsulfinyl groups, and arylsulfonyl groups. Preferred substituents are lower alkyl groups, and more particularly C1-C3 alkyl groups, especially methyl groups. One or more substituents may be present in -alkyl, -alkenyl, or -ynyl groups, particularly one or more C1-C3 alkyl groups, especially one or more methyl groups. Preferably, the organic acid is a C1-C6 alkyl carboxylic acid substituted with at least one C1-C3 alkyl group, more preferably a C1-C3 alkyl carboxylic acid substituted with at least one C1-C2 alkyl group, more preferably a C1-C3 alkyl carboxylic acid substituted with at least one methyl group, and even more preferably terpentine.

[0050] According to another alternative embodiment, the organic solvent is unsubstituted. In this case, the organic acid is preferably an unsubstituted C1-C20 alkyl carboxylic acid, more preferably an unsubstituted C1-C12 alkyl carboxylic acid, more preferably an unsubstituted C1-C6 alkyl carboxylic acid, more preferably an unsubstituted C1-C3 alkyl carboxylic acid, and even more preferably propionic acid.

[0051] In yet another embodiment, the organic acid is a dicarboxylic acid, such as a C2-C8 dicarboxylic acid, like malonic acid, succinic acid, and preferably adipic acid. As described above, the dicarboxylic acid can be substituted or, in particular, unsubstituted.

[0052] Ammonium salts can be mentioned as suitable salts of the aforementioned organic acids.

[0053] According to one embodiment, the organic acid is in the form of an aqueous solution. The concentration of the organic acid in the aqueous solution can be, for example, from 1 to 20 wt%, particularly from 2 to 10 wt%, and more particularly from 3 to 7 wt%. According to another embodiment, pure (i.e., undiluted) organic acid is used.

[0054] In step (a), the components (i), (ii), and (iii) that come into contact to form the mixture can be contacted in any order. Particularly according to one embodiment, an aqueous solution of the base (i) and an organic acid (iii) are contacted together, and the resulting mixture is contacted with an aqueous solution (ii) containing one or more cerium nitrates. In this case, since the base solution (i) is already in aqueous solution form, pure (i.e., undiluted) organic acid (iii) can be used. Contacting the mixture of (i) and (iii) with (ii) may include adding (ii) to the mixture, preferably under stirring and / or inert gas bubbling.

[0055] According to an alternative embodiment, an aqueous solution (ii) containing one or more cerium nitrates is contacted with an aqueous solution (i) of a base, and the resulting mixture is then contacted with an organic acid (iii). In this case, the organic acid (iii) may be used in its aqueous solution form. The contact between (ii) and (i) may include adding (ii) to (i), preferably under stirring and / or inert gas bubbling.

[0056] The organic acid (iii) can be used at concentrations ranging from 1 to 245 mmol / L, particularly from 2 to 150 mmol / L, more particularly from 5 to 100 mmol / L, and even more particularly from 5 to 50 mmol / L relative to the total volume of the mixture obtained in step (a). This range is particularly suitable for forming well-defined particles.

[0057] The amount of free oxygen in the mixture should be carefully controlled and minimized. This can be done by bubbling with an inert gas to degas one or more of the components (i), (ii), and (iii) and / or the resulting mixture. The term "inert gas" or "inert atmosphere" is intended to mean an atmosphere or gas free of oxygen, which may be, for example, nitrogen or argon.

[0058] Step (a) involves reacting components (i), (ii), and (iii). Step (a) is preferably carried out under an inert atmosphere, particularly in a closed reactor or as a purge with an inert gas in a semi-closed reactor. The contact is typically carried out in a stirred reactor.

[0059] Step (a) is typically performed at a temperature between 5°C and 50°C. This temperature can be between 20°C and 25°C.

[0060] Step (b) is the reaction medium obtained at the end of the previous step after heat treatment. It may include (i) a heating sub-step and (ii) an aging sub-step.

[0061] The heating sub-step (i) may include heating the medium at a temperature typically between 75°C and 95°C, and more particularly between 80°C and 90°C.

[0062] The aging sub-step (ii) may include maintaining the medium at a temperature between 75°C and 95°C, more particularly between 80°C and 90°C. The duration of this aging sub-step (ii) is between 2 hours and 20 hours. Empirically, the higher the temperature of the aging sub-step, the shorter the duration of the aging sub-step. For example, when the temperature of the aging sub-step is between 85°C and 90°C (e.g., 88°C), the duration of the aging sub-step may be between 2 hours and 15 hours, more particularly between 4 hours and 15 hours. When the temperature of the aging sub-step is between 75°C and 85°C (e.g., 80°C), the duration of the aging sub-step may be between 15 hours and 30 hours.

[0063] During step (b), Ce occurs III To Ce IV Oxidation. This step can also be carried out under an inert atmosphere, and the description of this atmosphere in step (a) also applies here. Similarly, this heat treatment can be carried out in a stirred reactor.

[0064] In step (c), the mixture obtained at the end of step (b) may optionally be acidified. This step (c) can be carried out using nitric acid. The reaction mixture can be acidified with HNO3 to a pH below 3.0, more particularly including a pH between 1.5 and 2.5.

[0065] In step (d), the solid material obtained at the end of step (b) or (c) is washed with water, preferably deionized water. This operation reduces the amount of residual nitrate in the dispersion and achieves the target conductivity. This step can be performed by filtering the solid from the mixture and redispersing the solid in water. Multiple filtrations and redispersions may be performed if necessary.

[0066] In step (e), the solid material obtained at the end of step (d) may be subjected to mechanical treatment to deagglomerate the particles. This step can be performed by dual-jet treatment or ultrasonic deagglomeration. This step typically results in a sharp particle size distribution and reduces the number of large agglomerate particles. According to an embodiment, the cerium oxide particles undergo deagglomeration mechanical treatment. According to another embodiment, the cerium oxide particles are not subjected to deagglomeration mechanical treatment.

[0067] Following step (e), the solid material can be dried to obtain cerium oxide particles in powder form. Following step (e), water or a mixture of water and a miscible organic compound can also be added to obtain a dispersion of cerium oxide particles in a liquid medium.

[0068] Another object of the present invention is cerium oxide particles that can be obtained or acquired by the methods described above.

[0069] This invention also relates to a dispersion of cerium oxide particles in a liquid medium. The dispersion comprises the cerium oxide particles of this invention and a liquid medium. The liquid medium may be water or a mixture of water and a water-miscible organic liquid. The water-miscible organic liquid should not cause the particles to precipitate or agglomerate. The water-miscible organic liquid may be, for example, alcohols such as isopropanol, ethanol, 1-propanol, methanol, 1-hexanol; ketones such as acetone, diacetone alcohol, methyl ethyl ketone; esters such as ethyl formate, propyl formate, ethyl acetate, methyl acetate, methyl lactate, butyl lactate, ethyl lactate. The water / organic liquid ratio may be between 80 / 20 and 99 / 1 (wt / wt).

[0070] The proportion of cerium oxide particles in the dispersion can range from 1.0 wt% to 40.0 wt%, expressed as the weight of the cerium oxide particles relative to the total weight of the dispersion. This proportion can also range from 10.0 wt% to 35.0 wt%.

[0071] This dispersion can also exhibit conductivity below 300 µS / cm, more particularly below 150 µS / cm, and even more particularly below 100 µS / cm or 50 µS / cm. The conductivity was measured using a conductivity meter 9382-10D from HORIBA, Ltd.

[0072] The cerium oxide particles or dispersions of the present invention can be used to prepare grinding compositions, more specifically, chemimechanical grinding compositions. They are used as components of grinding compositions, more specifically, chemimechanical grinding compositions.

[0073] This invention also relates to a chemical mechanical polishing composition. A chemical mechanical polishing composition (or chemi-mechanical polishing composition) is an polishing composition used to selectively remove material from the surface of a substrate. It is used in the fields of integrated circuits and other electronic devices. In practice, in the manufacture of integrated circuits and other electronic devices, multiple layers of conductive, semi-conductive, and dielectric materials are deposited onto or removed from the surface of a substrate. When material layers are sequentially deposited onto and removed from the substrate, the uppermost surface of the substrate may become uneven and require planarization. Planarization (or “polishing”) is the process of removing material from the substrate surface to form a generally uniform planar surface. Planarization can be used to remove unwanted surface features and surface defects such as rough surfaces, agglomerated material, lattice damage, scratches, and contamination layers or materials. Planarization can also be used to form features on a substrate by removing excess deposited material used to fill features and providing a uniform surface for subsequent metallization and processing.

[0074] The substrate that can be ground using an abrasive composition or a chemimechanical abrasive composition can be, for example, a silicon dioxide substrate, glass, a semiconductor, or a wafer.

[0075] The particles or dispersions of the present invention can be used to prepare chemimechanical milling compositions. Therefore, the present invention also relates to chemimechanical milling compositions comprising cerium oxide particles or dispersions as defined above.

[0076] This grinding composition or chemical mechanical grinding composition typically contains different components other than cerium oxide particles. The grinding composition may contain one or more of the following components: - Abrasive particles other than the cerium oxide particles or dispersions of the present invention; and / or - pH adjuster; and / or - Surfactants; and / or - Rheology control agents, including viscosity enhancers and coagulants; and / or - Additives selected from the following: nonionic polymers, cationic polymers, anionic polymers, quaternary ammonium compounds, silanes, sulfonated monomers, phosphomeric monomers, acrylates, starch, cyclodextrins, and combinations thereof.

[0077] The pH of this grinding composition is typically between 1 and 6. Typically, the grinding composition has a pH of 3.0 or higher. Furthermore, the pH of this grinding composition is typically 6.0 or lower.

[0078] The present invention also relates to a method for removing a portion of a substrate, the method comprising grinding the substrate with the grinding composition described above.

[0079] Finally, this invention relates to a semiconductor ground by this method.

[0080] If any disclosure of any patent, patent application, or publication incorporated herein by reference conflicts with the description of this application to the extent that it may lead to ambiguity in terminology, then this description shall take precedence.

[0081] The invention will now be further illustrated by examples, without any intention to limit the invention.

[0082] Example Example 1 A cerium nitrate solution was prepared by mixing 111.3 g of 2.87 M trivalent cerium nitrate, 16.82 g of 68% HNO3, and 3.26 g of deionized water. This solution was placed in a 250 mL semi-closed container. Cerium (IV) nitrate was then added to the cerium nitrate solution at a molar ratio of 1 / 5000 cerium IV / total cerium. An ammonia solution was prepared by mixing 74.55 g of 13.35 M ammonia and 623.03 g of deionized water. This solution was placed in a 1 L semi-closed jacketed reactor and bubbled with N2 gas at a flow rate of 210 L / h for 1 hour with stirring. The cerium nitrate solution was added to the ammonia solution over approximately 30 min under the same stirring and N2 bubbling conditions. An organic acid solution was prepared by adding 0.90 g of pentyl acid to 20 g of deionized water, bubbling it with N2 gas for 1 hour, and then adding it to the reactor. The reaction mixture was heated to 85°C over approximately 1 hour and maintained for approximately 4 hours under the same stirring conditions and a reduced N2 bubbling flow rate (below 10 L / h). The reaction mixture was cooled and acidified to pH 2 with 68% HNO3. After decantation, the supernatant was removed and NH4OH was added to the slurry to achieve pH 8.

[0083] The reaction mixture was washed with deionized water by centrifugation. The washing was repeated when the conductivity of the washing solution was less than 0.04 mS / cm.

[0084] The BET specific surface area, determined by nitrogen adsorption, was 37.9 m² / g. The suspension was observed by TEM; for approximately 80 particles representative of the suspension, each particle was counted and measured. The average particle size was 193 nm, and the standard deviation was 39 nm (corresponding to 20% of the average particle size). The SSA size, determined as described in this specification, was equal to 22, and the roughness index RI, determined as described in this specification, was 8.8. The percentage of carbon was determined to be %C = 0.4 wt%. TEM images of the obtained spherical rough particles are shown in [images / images]. Figure 1 Report from the Central Committee.

[0085] Example 2 A cerium nitrate solution was prepared by mixing 111.3 g of 2.87 M trivalent cerium nitrate, 16.81 g of 68% HNO3, and 3.25 g of deionized water. This solution was placed in a 250 mL semi-closed container. Cerium (IV) nitrate was then added to the cerium nitrate solution at a molar ratio of 1 / 5000 cerium IV / total cerium. An ammonia solution was prepared by mixing 74.20 g of 13.35 M ammonia, 643.50 g of deionized water, and 0.92 g of pentanoic acid. This solution was placed in a 1 L semi-closed jacketed reactor and bubbled with N2 gas at a flow rate of 210 L / h for 1 hour with stirring. The cerium nitrate solution was added to the ammonia solution over approximately 30 min under the same stirring and N2 bubbling conditions. The reaction mixture was heated to 85 °C over approximately 1 hour and maintained for approximately 4 hours with the same stirring and a reduced N2 bubbling flow rate (below 10 L / h). The reaction mixture was cooled and acidified to pH 2 with 68% HNO3. After decantation, the supernatant was removed and NH4OH was added to the slurry to achieve pH 8.

[0086] The reaction mixture was washed with deionized water by centrifugation. The washing was repeated when the conductivity of the washing solution was less than 0.04 mS / cm.

[0087] The BET specific surface area, determined by nitrogen adsorption, was 44.8 m² / g. The suspension was observed by TEM; for approximately 80 particles representative of the suspension, each particle was counted and measured. The average particle size was 165 nm with a standard deviation of 50 nm (corresponding to 30% of the average particle size). The SSA size, determined as described in this specification, was equal to 19, and the roughness index RI, determined as described in this specification, was 8.9. The percentage of carbon was determined to be %C = 0.37 wt%. TEM images of the obtained spherical rough particles are shown in […]. Figure 2 Report from the Central Committee.

[0088] Example 3 A cerium nitrate solution was prepared by mixing 222.4 g of 2.87 M trivalent cerium nitrate and 33.9 g of 68% HNO3. This solution was placed in a 250 mL semi-closed container. Cerium (IV) nitrate was then added to the cerium nitrate solution at a molar ratio of 1 / 5000 of cerium IV to total cerium. An ammonia solution was prepared by mixing 133.1 g of 15 M ammonia, 1297.7 g of deionized water, and 0.83 g of pentanoic acid. This solution was placed in a 2 L semi-closed jacketed reactor and bubbled with N2 gas at a flow rate of 100 L / h for 1 hour with stirring. The cerium nitrate solution was added to the ammonia solution over approximately 30 min under the same stirring and N2 bubbling conditions. The reaction mixture was heated to 80 °C over approximately 1 hour and maintained for approximately 4 hours under the same stirring and reduced N2 bubbling flow rate (below 10 L / h). The reaction mixture was cooled and acidified to pH 2 with 68% HNO3. After decantation, the supernatant is removed and NH4OH is added to the slurry to achieve pH 8.

[0089] The reaction mixture was washed with deionized water by centrifugation. The washing was repeated when the conductivity of the washing solution was less than 0.04 mS / cm.

[0090] The BET specific surface area, determined by nitrogen adsorption, was 23 m² / g. The suspension was observed by TEM; for approximately 150 particles representative of the suspension, each particle was counted and measured. The average particle size was 81 nm with a standard deviation of 30 nm (corresponding to 37% of the average particle size). The SSA size, determined as described in this specification, was 36, and the roughness index RI, determined as described in this specification, was 2.2. The percentage of carbon was determined to be %C = 0.21 wt%. TEM images of the obtained spherical rough particles are shown in […]. Figure 3 Report from the Central Committee.

[0091] Example 4 A cerium nitrate solution was prepared by mixing 222.4 g of 2.87 M trivalent cerium nitrate and 33.9 g of 68% HNO3. This solution was placed in a 250 mL semi-closed container. Cerium (IV) nitrate was then added to the cerium nitrate solution at a molar ratio of 1 / 5000 of cerium IV to total cerium. An ammonia solution was prepared by mixing 133.9 g of 14.9 M ammonia, 1296.8 g of deionized water, and 1.18 g of adipic acid. This solution was placed in a 2 L semi-closed jacketed reactor and bubbled with N2 gas at a flow rate of 100 L / h for 1 hour with stirring. The cerium nitrate solution was added to the ammonia solution over approximately 30 min under the same stirring and N2 bubbling conditions. The reaction mixture was heated to 80 °C over approximately 1 hour and maintained for approximately 4 hours under the same stirring and reduced N2 bubbling flow rate (below 10 L / h). The reaction mixture was cooled and acidified to pH 2 with 68% HNO3. After decantation, the supernatant was removed and NH4OH was added to the slurry to achieve pH 8.

[0092] The reaction mixture was washed with deionized water by centrifugation. The washing was repeated when the conductivity of the washing solution was less than 0.04 mS / cm.

[0093] The BET specific surface area, determined by nitrogen adsorption, was 35 m² / g. The suspension was observed by TEM; for approximately 220 particles representative of the suspension, each particle was counted and measured. The average particle size was 87 nm with a standard deviation of 34 nm (corresponding to 39% of the average particle size). The SSA size, determined as described in this specification, was equal to 24, and the roughness index RI, determined as described in this specification, was 3.6. The percentage of carbon was determined to be %C = 0.61 wt%. TEM images of the obtained spherical rough particles are shown in […]. Figure 4 Report from the Central Committee.

[0094] Comparison Example 1 A cerium nitrate solution was prepared by mixing 139.1 g of 2.87 M trivalent cerium nitrate, 21.1 g of 68% HNO3, and 4 g of deionized water. This solution was placed in a 250 mL semi-closed container. Cerium (IV) nitrate was then added to the cerium nitrate solution at a molar ratio of 1 / 5000 of cerium IV to total cerium. An ammonia solution was prepared by mixing 100.5 g of 13.35 M ammonia and 795.5 g of deionized water. This solution was placed in a 1 L semi-closed jacketed reactor and bubbled with N2 gas at a flow rate of 210 L / h for 1 hour with stirring. The cerium nitrate solution was added to the ammonia solution over approximately 30 min under the same stirring and N2 bubbling conditions. The reaction mixture was heated to 85 °C over approximately 1 hour and maintained for approximately 4 hours with the same stirring and a reduced N2 bubbling flow rate (below 10 L / h). The reaction mixture was cooled and acidified to pH 2 with 68% HNO3. After decantation, the supernatant was removed and NH4OH was added to the slurry to achieve pH 8.

[0095] The reaction mixture was washed with deionized water by centrifugation. The washing was repeated when the conductivity of the washing solution was less than 0.04 mS / cm.

[0096] The BET specific surface area, determined by nitrogen adsorption, was 16.8 m² / g. The suspension was observed by TEM; for approximately 150 particles representative of the suspension, each particle was counted and measured. The average particle size was 87 nm, and the standard deviation was 21 nm (corresponding to 24% of the average particle size). The SSA size, determined as described in this specification, was equal to 50, and the roughness index RI, determined as described in this specification, was 1.7. TEM images are available at [link to image]. Figure 5 Report from the Central Committee.

Claims

1. Cerium oxide particles, characterized in that, The particles are spherical in shape and exhibit a roughness index RI of at least 2, where RI is defined by the following formula: Wherein "TEM size" represents the average size of the particles measured from at least 80 particles in a transmission electron microscope image, and "SSA size" represents the theoretical average size of the particles according to the following formula: Where SSA represents the BET specific surface area of ​​the particles as determined by nitrogen adsorption, and ρ represents the density of cerium oxide (IV) equal to 7.22 g / cm³. 3 Furthermore, the particles described therein exhibit a sphericity ratio (SR) between 0.8 and 1.

0. The following equation is used to calculate SR from the perimeter P and area A of the measured particle projection: SR is determined by dynamic image analysis (DIA), particularly according to ISO 13322-2 (2006).

2. The cerium oxide particles according to claim 1, characterized in that... The roughness index RI is at least 3.

5.

3. The cerium oxide particles according to any one of claims 1 and 2, characterized in that... The particles exhibit a sphericity ratio SR between 0.85 and 1.0, and more particularly between 0.90 and 1.

4. The cerium oxide particles according to any one of claims 1 to 3, characterized in that, The particles exhibit characteristics including 30 and 100 m 2 Between / g, and more specifically between 32 and 80 m 2 Between / g, and more specifically between 35 and 70 m 2 Between / g, and even more specifically between 36 and 60 m 2 Specific surface area between / g.

5. The cerium oxide particles according to any one of claims 1 to 3, characterized in that, The particles exhibit characteristics including 20 and 40 m 2 Specific surface area between / g.

6. The cerium oxide particles according to any one of claims 1 to 5, characterized in that, The particles exhibit an average size ranging from 30 to 500 nm, particularly from 70 to 300 nm, which was measured by TEM images.

7. The cerium oxide particles according to any one of claims 1 to 5, characterized in that, The particles exhibit an average size between 140 and 300 nm, particularly between 145 and 270 nm, more particularly between 150 and 250 nm, and even more particularly between 155 and 240 nm, the average size being measured by TEM images.

8. A dispersion of cerium oxide particles in a liquid medium according to any one of claims 1 to 7.

9. The dispersion according to claim 8, characterized in that... The dispersion contains between 1.0 wt% and 40.0 wt% cerium oxide particles.

10. The dispersion according to claim 8 or 9, characterized in that... The liquid medium is water or a mixture of water and water-miscible organic liquids.

11. The dispersion according to any one of claims 8 to 10, characterized in that... The dispersion exhibits conductivity below 300 µS / cm, more particularly below 150 µS / cm, and even more particularly below 100 µS / cm or 50 µS / cm.

12. Use of the cerium oxide particles according to any one of claims 1 to 7 or the dispersion according to any one of claims 8 to 11 for the preparation of grinding compositions, more particularly CMP compositions.

13. A grinding composition comprising cerium oxide particles according to any one of claims 1 to 7 or a dispersion according to any one of claims 8 to 11.

14. The grinding composition according to claim 13, characterized in that... The composition further comprises one or more of the following ingredients: (i) Abrasive particles other than cerium oxide particles or dispersions; and / or (ii) pH adjusters; and / or (iii) Surfactants; and / or (iv) Rheology control agents, including viscosity enhancers and coagulants; and / or (v) The additives are selected from the following: nonionic polymers, cationic polymers, anionic polymers, quaternary ammonium compounds, silanes, sulfonated monomers, phosphomeric monomers, acrylates, starch, cyclodextrins, and combinations thereof.

15. The grinding composition according to claim 13 or 14, characterized in that... The composition exhibits a pH between 1 and 6.

16. A method for removing a portion of a substrate, the method comprising grinding the substrate with the abrasive composition according to claim 12.

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