Particles and selection method thereof, abrasive grain manufacturing method, polishing liquid manufacturing method, polishing method, component manufacturing method, and semiconductor component manufacturing method

Abstract

To provide a method for selecting particles for obtaining abrasive grains, which allows adjustment of the polishing rate of a material to be polished when the material is polished using the abrasive grains.SOLUTION: There is provided a method for selecting particles for obtaining abrasive grains, the particles containing cerium are selected on the basis of an average positron lifetime measured by positron annihilation spectroscopy. There is also provided a method for manufacturing abrasive grains containing cerium, the particles being selected by the particle selection method are pulverized. There is also provided a method for manufacturing a polishing liquid, including mixing abrasive grains obtained by the method for manufacturing abrasive grains with water. There is provided a polishing method, including polishing a workpiece using the polishing liquid obtained by the method for manufacturing a polishing liquid.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to particles and a method for selecting the particles, a method for manufacturing abrasive grains, a method for manufacturing a polishing liquid, a polishing method, a method for manufacturing parts, a method for manufacturing semiconductor parts, and the like. [Background technology]

[0002] In recent years, processing technologies for achieving higher density and miniaturization have become increasingly important in the manufacturing process of electronic devices. CMP (Chemical Mechanical Polishing), one of the processing technologies, is essential in the manufacturing process of electronic devices for forming shallow trench isolation (STI), planarizing pre-metal insulating materials or interlayer insulating materials, and forming plugs or buried metal wiring. Known polishing solutions used in CMP include those containing abrasive grains containing cerium oxide (see, for example, Patent Documents 1 and 2 listed below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-106994 [Patent Document 2] Japanese Patent Application Publication No. 08-022970 Summary of the Invention [Problem to be solved by the invention]

[0004] The abrasive grains used in the polishing liquid can be obtained by subjecting particles to a grinding process, etc. For polishing liquids containing such abrasive grains, it is necessary to adjust the polishing rate of the material to be polished depending on the application, and a new method for adjusting the polishing rate of the material to be polished is required.

[0005] One aspect of the present disclosure aims to provide a method for selecting particles for obtaining abrasive grains, the method being capable of adjusting the polishing rate of a material to be polished when the material is polished using the abrasive grains. Another aspect of the present disclosure aims to provide a method for manufacturing abrasive grains using particles selected by the particle selection method. Another aspect of the present disclosure aims to provide a method for manufacturing a polishing liquid using abrasive grains obtained by the method for manufacturing abrasive grains. Another aspect of the present disclosure aims to provide a polishing method using a polishing liquid obtained by the method for manufacturing a polishing liquid. Another aspect of the present disclosure aims to provide a method for manufacturing a component using a polished member polished by the polishing method. Another aspect of the present disclosure aims to provide a method for manufacturing a semiconductor component using a polished member polished by the polishing method. Another aspect of the present disclosure aims to provide particles for obtaining abrasive grains, the method being capable of adjusting the polishing rate of a material to be polished when the material is polished using the abrasive grains. [Means for solving the problem]

[0006] In some aspects, the present disclosure relates to the following [1] to

[11] , etc. [1] A method for selecting particles for obtaining abrasive grains, the particles containing cerium, and the particles are selected based on the average value of the positron lifetime measured by positron annihilation spectroscopy. [2] The method for selecting particles according to [1], wherein the particles contain cerium oxide. [3] A method for producing abrasive grains containing cerium, which comprises pulverizing particles selected by the particle selection method described in [1] or [2]. [4] The method for producing abrasive grains according to [3], wherein the abrasive grains contain cerium oxide. [5] A method for producing a polishing liquid, which comprises mixing abrasive grains obtained by the method for producing abrasive grains according to [3] or [4] with water. [6] A polishing method, comprising polishing a workpiece using the polishing liquid obtained by the method for producing a polishing liquid according to [5]. [7] The polishing method according to [6], wherein the polished member contains silicon oxide. [8] A method for manufacturing a part, comprising obtaining a part using a polished member polished by the polishing method according to [6] or [7]. [9] A method for manufacturing a semiconductor component, comprising obtaining a semiconductor component using a polished member polished by the polishing method according to [6] or [7].

[10] Particles for obtaining abrasive grains, which contain cerium and have an average positron lifetime of 330 ps or more as measured by positron annihilation spectroscopy.

[11] The particles according to

[10] , which contain cerium oxide. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, there is provided a method for selecting particles for obtaining abrasive grains, the method being capable of adjusting the polishing rate of a material to be polished when the material is polished using the abrasive grains. According to another aspect of the present disclosure, there is provided a method for manufacturing abrasive grains using particles selected by the particle selection method. According to another aspect of the present disclosure, there is provided a method for manufacturing a polishing liquid using abrasive grains obtained by the abrasive grain manufacturing method. According to another aspect of the present disclosure, there is provided a polishing method using a polishing liquid obtained by the polishing liquid manufacturing method. According to another aspect of the present disclosure, there is provided a method for manufacturing a component using a polished member polished by the polishing method. According to another aspect of the present disclosure, there is provided a method for manufacturing a semiconductor component using a polished member polished by the polishing method. According to another aspect of the present disclosure, there is provided particles for obtaining abrasive grains, the method being capable of adjusting the polishing rate of a material to be polished when the material is polished using the abrasive grains. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described, but the present disclosure is not limited to the following embodiments.

[0009] In this specification, numerical ranges indicated with "to" indicate a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. A numerical range "A or greater" means a range exceeding A and A. A numerical range "A or less" means a range less than A and A. In numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of a numerical range of another stage. In numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in an experimental example. "A or B" may include either A or B, or may include both. Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition refers to the total amount of those multiple substances present in the composition, unless otherwise specified. The term "process" does not only refer to an independent process, but also includes processes that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. "Abrasive grain" refers to a collection of multiple particles, but for convenience, a single particle that makes up an abrasive grain may be called an abrasive grain.

[0010] The particles and the selection method thereof according to this embodiment are particles and a selection method thereof for obtaining abrasive grains (abrasive grains used in polishing liquids). In the particles and the selection method according to this embodiment, the particles contain cerium. In the particle selection method according to this embodiment, particles are selected based on the average value of positron lifetimes (average positron lifetime) measured by positron annihilation spectroscopy. The particles according to this embodiment have any value as the average value (average positron lifetime) of positron lifetimes (positron lifetimes of particles) measured by positron annihilation spectroscopy, depending on the application.

[0011] The present inventors have focused on cerium-containing particles as particles for obtaining abrasive grains by grinding or other processes, and have found that by adjusting the average positron lifetime of the particles measured by positron annihilation spectroscopy, the polishing rate of the material being polished using the abrasive grains can be adjusted. According to the particles and selection method of the present embodiment, particles are selected based on the average positron lifetime measured by positron annihilation spectroscopy, and abrasive grains are obtained using such particles, thereby adjusting the polishing rate of the material being polished using the abrasive grains. According to the particles and selection method of the present embodiment, the particles are ground (which may be classified to a specific particle size after grinding) to obtain abrasive grains, thereby adjusting the polishing rate of the material being polished using the abrasive grains. According to the present embodiment, a polishing rate adjustment method can be provided, in which the polishing rate of the material being polished is adjusted based on the average positron lifetime of the particles used to obtain the abrasive grains (the average positron lifetime measured by positron annihilation spectroscopy).

[0012] According to one aspect of the particles and the method for selecting the particles of this embodiment, it is possible to adjust the polishing rate of the material to be polished on the patterned wafer (for example, the polishing rate 60 seconds after the start of polishing). According to one aspect of the particles and the method for selecting the particles of this embodiment, it is possible to adjust the polishing rate of the material to increase the polishing rate of the material to be polished, and it is also possible to adjust the polishing rate of the material to decrease the polishing rate of the material to be polished. According to one aspect of the particles and the method for selecting the particles of this embodiment, it is possible to adjust the polishing rate of the insulating material, and it is possible to adjust the polishing rate of silicon oxide.

[0013] The particles used to obtain the abrasive grains contain cerium (cerium element) and may contain a cerium compound. Examples of cerium compounds include cerium oxide, cerium hydroxide, ammonium cerium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromate, cerium bromide, cerium chloride, cerium oxalate, cerium nitrate, and cerium carbonate. The particles may contain cerium oxide to facilitate adjustment of the polishing rate of the material to be polished. The cerium oxide may be CeO2 (cerium (IV) oxide, ceria) or Ce2O3 (cerium (III) oxide).

[0014] Particles for obtaining abrasive grains can be obtained by oxidizing a cerium source containing cerium (e.g., a cerium salt). Examples of oxidation methods include a calcination method in which the cerium source is calcined at 600 to 900°C or the like; and a chemical oxidation method in which the cerium source is oxidized using an oxidizing agent such as hydrogen peroxide. Examples of cerium sources include cerium carbonate, cerium oxycarbonate, cerium trimesate, cerium acetate, cerium stearate, cerium nitrate, cerium sulfate, cerium oxalate, and cerium hydroxide. The particles for obtaining abrasive grains may contain particles derived from cerium oxycarbonate, which facilitates adjustment of the polishing rate of the material to be polished.

[0015] Positron lifetime measurements can evaluate atomic-level defects, intermolecular voids, pore structures, and the like by measuring the time it takes for a positron incident on a material to annihilate. The average positron lifetime is the component derived from a sample when a three-component analysis is performed using two components, a Kapton component and an adhesive component, as the radiation source components after measuring the positron lifetime by positron annihilation. The average positron lifetime can be used, for example, as an indicator of the average size of oxygen defects. In addition to the average positron lifetime, positron lifetime measurements can also obtain a minor component value (the numerical value of the minor component) and a major component value (the numerical value of the major component) of the positron lifetime. The minor component value of the positron lifetime is the smallest positron lifetime among the positron lifetimes derived from a sample when a four-component analysis is performed after measuring the positron lifetime by positron annihilation, and the major component value of the positron lifetime is the second smallest positron lifetime among the positron lifetimes derived from the sample when the four-component analysis is performed. The minor component value of the positron lifetime can be used, for example, as an indicator of a single oxygen defect. The large component value of the positron lifetime can be used, for example, as an index of oxygen vacancy clusters. The average value, small component value, and large component value of the positron lifetime can be measured by the method described in the experimental examples below. The average value, small component value, and large component value of the positron lifetime can be adjusted by the particle preparation conditions for obtaining abrasive grains, etc. For example, the higher the firing temperature of the cerium source, the shorter the positron lifetime tends to be.

[0016] The smaller the average value, minor component value, or major component value of the positron lifetime, the higher the polishing rate (e.g., the polishing rate 60 seconds after the start of polishing). It is presumed that the smaller the positron lifetime (average value, minor component value, or major component value) of the particles used to obtain the abrasive grains, the smaller the oxygen defects inside the particles, and that the oxygen defects inside the abrasive grains obtained using such particles are also small. It is presumed that such small oxygen defects inside the abrasive grains make them less likely to crack during polishing, suppress a decrease in the mechanical polishing power of the abrasive grains, and make it easier to obtain a high polishing rate.

[0017] The particle selection method according to this embodiment includes a selection step of selecting particles (particles for obtaining abrasive grains) based on the average value of the positron lifetime measured by positron annihilation spectroscopy. In the selection step, particles may be selected based on at least one value selected from the group consisting of the minor and major component values ​​of the positron lifetime, in addition to the average value of the positron lifetime. In the selection step, particles may be selected based on whether the average value of the positron lifetime is within any of the following ranges, and particles may be selected based on whether at least one value selected from the group consisting of the minor and major component values ​​of the positron lifetime, in addition to the average value of the positron lifetime, is within any of the following ranges. In the particles according to this embodiment, the average value of the positron lifetime may be within any of the following ranges, and at least one value selected from the group consisting of the minor and major component values ​​of the positron lifetime may be within any of the following ranges.

[0018] The average positron lifetime may be 200 ps or more, 250 ps or more, 280 ps or more, 285 ps or more, 300 ps or more, 310 ps or more, 320 ps or more, 330 ps or more, 335 ps or more, 340 ps or more, 345 ps or more, 350 ps or more, 355 ps or more, or 360 ps or more. The average positron lifetime may be 500 ps or less, 450 ps or less, 400 ps or less, 390 ps or less, 380 ps or less, 370 ps or less, 365 ps or less, 360 ps or less, 355 ps or less, 350 ps or less, 345 ps or less, 340 ps or less, or 335 ps or less. From these viewpoints, the average value of the positron lifetime may be 200 to 500 ps, ​​200 to 370 ps, ​​200 to 355 ps, 300 to 500 ps, ​​300 to 370 ps, ​​300 to 355 ps, 350 to 500 ps, ​​350 to 370 ps, ​​or 350 to 355 ps.

[0019] The value of the minor component of the positron lifetime may be 100 ps or more, 150 ps or more, 200 ps or more, 210 ps or more, 220 ps or more, 230 ps or more, 240 ps or more, 250 ps or more, 260 ps or more, 270 ps or more, 280 ps or more, or 285 ps or more. The value of the minor component of the positron lifetime may be 400 ps or less, 350 ps or less, 300 ps or less, 290 ps or less, 285 ps or less, 280 ps or less, 270 ps or less, 260 ps or less, 250 ps or less, 240 ps or less, 230 ps or less, or 220 ps or less. From these viewpoints, the value of the minor component of the positron lifetime may be 100 to 400 ps, ​​100 to 300 ps, ​​100 to 250 ps, ​​200 to 400 ps, ​​200 to 300 ps, ​​200 to 250 ps, ​​245 to 400 ps, ​​245 to 300 ps, ​​or 245 to 250 ps.

[0020] The value of the major component of the positron lifetime may be 300 ps or more, 350 ps or more, 400 ps or more, 410 ps or more, 420 ps or more, 425 ps or more, 430 ps or more, 435 ps or more, 440 ps or more, 445 ps or more, 450 ps or more, 455 ps or more, 460 ps or more, 470 ps or more, 480 ps or more, 490 ps or more, 495 ps or more, 500 ps or more, 505 ps or more, or 510 ps or more. The value of the large component of the positron lifetime may be 600 ps or less, 550 ps or less, 540 ps or less, 530 ps or less, 520 ps or less, 515 ps or less, 510 ps or less, 505 ps or less, 500 ps or less, 495 ps or less, 490 ps or less, 480 ps or less, 470 ps or less, 460 ps or less, 455 ps or less, 450 ps or less, 445 ps or less, 440 ps or less, or 435 ps or less. From these viewpoints, the value of the large component of the positron lifetime may be 300 to 600 ps, ​​300 to 520 ps, ​​300 to 500 ps, ​​400 to 600 ps, ​​400 to 520 ps, ​​400 to 500 ps, ​​450 to 600 ps, ​​450 to 520 ps, ​​or 450 to 500 ps.

[0021] The crystallite size of the particles used to obtain the abrasive grains may be in the following ranges. The crystallite size may be 1 nm or more, 5 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, 21 nm or more, 22 nm or more, 23 nm or more, 24 nm or more, 25 nm or more, 25.5 nm or more, 26 nm or more, 27 nm or more, or 28 nm or more. The crystallite size may be 50 nm or less, 45 nm or less, 40 nm or less, 35 nm or less, 30 nm or less, 29 nm or less, 28 nm or less, 27 nm or less, 26 nm or less, 25.5 nm or less, or 25 nm or less. From these perspectives, the crystallite size may be 1 to 50 nm, 1 to 40 nm, 1 to 30 nm, 10 to 50 nm, 10 to 40 nm, 10 to 30 nm, 20 to 50 nm, 20 to 40 nm, or 20 to 30 nm. The crystallite size can be measured by the method described in the Experimental Examples below. The crystallite size can be adjusted by the particle production conditions for obtaining the abrasive grains (for example, the firing temperature of the cerium source).

[0022] The abrasive grains and the method for manufacturing the same according to the present embodiment are abrasive grains containing cerium and a method for manufacturing the same. In the method for manufacturing the abrasive grains according to the present embodiment, it is possible to obtain abrasive grains by processing particles selected by the method for selecting particles according to the present embodiment. For example, the abrasive grains may be obtained by pulverizing the particles selected by the method for selecting particles according to the present embodiment. The abrasive grains according to the present embodiment are abrasive grains obtained by processing particles selected by the method for selecting particles according to the present embodiment (abrasive grains obtained by the method for manufacturing the abrasive grains according to the present embodiment). For example, the abrasive grains may be abrasive grains obtained by pulverizing the particles selected by the method for selecting particles according to the present embodiment. The pulverized product according to the present embodiment is a pulverized product of particles selected by the method for selecting particles according to the present embodiment.

[0023] The abrasive grains contain cerium (elemental cerium) and may contain a cerium compound. Examples of cerium compounds include cerium oxide, cerium hydroxide, ammonium cerium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromate, cerium bromide, cerium chloride, cerium oxalate, cerium nitrate, and cerium carbonate. The abrasive grains may contain cerium oxide, which facilitates increasing the polishing rate of the material to be polished. The cerium oxide may be CeO2 (cerium (IV) oxide, ceria) or Ce2O3 (cerium (III) oxide).

[0024] The method for manufacturing abrasive grains according to this embodiment may include a grinding step in which particles selected by the particle selection method according to this embodiment are ground to obtain a ground product, and may include a classification step in which the ground product is classified after the grinding step. In the classification step, coarse particles can be removed. The grinding method used in the grinding step is not particularly limited, and various grinding methods such as wet grinding and dry grinding can be used. The classification method used in the classification step is not particularly limited, and examples thereof include centrifugation.

[0025] The polishing liquid according to this embodiment contains the abrasive grains according to this embodiment (abrasive grains obtained by the method for manufacturing abrasive grains according to this embodiment) and water. The polishing liquid according to this embodiment may contain, in addition to the abrasive grains and water, components other than the abrasive grains and water (e.g., various components described below). The multi-component polishing liquid according to this embodiment includes Liquid A containing the abrasive grains according to this embodiment (abrasive grains obtained by the method for manufacturing abrasive grains according to this embodiment) and water, and Liquid B containing the abrasive grains, water, and components other than the abrasive grains and water (e.g., various components described below). Liquid A may contain components other than the abrasive grains and water (e.g., various components described below), or it may not contain components other than the abrasive grains and water (e.g., various components described below). In the method for manufacturing a polishing liquid according to this embodiment, the polishing liquid may be obtained by mixing the abrasive grains according to this embodiment (abrasive grains obtained by the method for manufacturing abrasive grains according to this embodiment) with water, or the polishing liquid may be obtained by mixing Liquid A and Liquid B of the multi-component polishing liquid according to this embodiment. Liquid A can be obtained by mixing the abrasive grains according to this embodiment (abrasive grains obtained by the method for manufacturing abrasive grains according to this embodiment) with water. Liquid B may be a plurality of liquids, for example, a plurality of liquids having different types of components other than the abrasive grains and water.

[0026] The content of the abrasive grains may be in the following ranges based on the total mass of the polishing liquid or the total mass of water: From the viewpoint of easily increasing the polishing rate of the material to be polished, the content of the abrasive grains may be 0.01 mass % or more, 0.05 mass % or more, 0.1 mass % or more, 0.2 mass % or more, 0.3 mass % or more, 0.4 mass % or more, or 0.5 mass % or more. The content of the abrasive grains may be 10% by mass or less, 8% by mass or less, 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.8% by mass or less, or 0.5% by mass or less, from the viewpoint of easily suppressing an increase in the viscosity of the polishing liquid, aggregation of the abrasive grains, etc. From these viewpoints, the content of the abrasive grains may be 0.01 to 10% by mass, 0.01 to 5% by mass, 0.01 to 1% by mass, 0.05 to 10% by mass, 0.05 to 5% by mass, 0.05 to 1% by mass, 0.1 to 10% by mass, 0.1 to 5% by mass, or 0.1 to 1% by mass.

[0027] Water may be contained as the remainder after removing other components from the polishing liquid. The water content may be in the following ranges based on the total mass of the polishing liquid. The water content may be 90% by mass or more, 91% by mass or more, 92% by mass or more, 93% by mass or more, 94% by mass or more, 95% by mass or more, 96% by mass or more, 97% by mass or more, 98% by mass or more, or 99% by mass or more. The water content may be less than 100% by mass, 99.9% by mass or less, 99.8% by mass or less, 99.7% by mass or less, 99.6% by mass or less, 99.5% by mass or less, 99.4% by mass or less, 99.3% by mass or less, or 99.2% by mass or less. From these perspectives, the water content may be 90% by mass or more but less than 100% by mass, 95% by mass or more but less than 100% by mass, or 98% by mass or more but less than 100% by mass.

[0028] The polishing liquid according to this embodiment may contain a phosphate compound as needed. The phosphate compound may be used as a dispersant for abrasive grains. As the phosphate compound, at least one selected from the group consisting of phosphates and their derivatives (phosphate derivatives) may be used. As the hydrogen phosphate compound, at least one selected from the group consisting of hydrogen phosphates and their derivatives (hydrogen phosphate derivatives) may be used.

[0029] Examples of phosphates include potassium phosphate, sodium phosphate, ammonium phosphate, calcium phosphate, etc., and specific examples include tripotassium phosphate, trisodium phosphate, ammonium phosphate, tricalcium phosphate, etc. Examples of phosphate derivatives include sodium diphosphate, potassium diphosphate, potassium polyphosphate, ammonium polyphosphate, calcium polyphosphate, etc.

[0030] Examples of hydrogen phosphate salts include potassium hydrogen phosphate salt, sodium hydrogen phosphate salt, ammonium hydrogen phosphate salt, calcium hydrogen phosphate salt, etc., and specific examples include dipotassium hydrogen phosphate, disodium hydrogen phosphate, diammonium hydrogen phosphate, calcium hydrogen phosphate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, ammonium dihydrogen phosphate, calcium dihydrogen phosphate, etc. Examples of hydrogen phosphate salt derivatives include potassium dodecyl hydrogen phosphate, sodium dodecyl hydrogen phosphate, dodecylammonium hydrogen phosphate, etc.

[0031] The polishing liquid according to this embodiment may contain hydrogen phosphate or ammonium dihydrogen phosphate, from the viewpoint of easily increasing the polishing rate of the material to be polished.

[0032] The content of the phosphate compound may be in the following ranges based on the total mass of the polishing liquid or the total mass of water. From the viewpoint of easily increasing the polishing rate of the material to be polished, the content of the phosphate compound may be 0.0001% by mass or more, 0.0005% by mass or more, 0.001% by mass or more, 0.002% by mass or more, 0.003% by mass or more, 0.004% by mass or more, or 0.005% by mass or more. From the viewpoint of easily suppressing aggregation of abrasive grains, the content of the phosphate compound may be 1% by mass or less, 0.5% by mass or less, 0.1% by mass or less, 0.08% by mass or less, 0.05% by mass or less, 0.03% by mass or less, 0.01% by mass or less, 0.008% by mass or less, or 0.005% by mass or less. From these viewpoints, the content of the phosphate compound may be 0.0001 to 1 mass%, 0.0001 to 0.1 mass%, 0.0001 to 0.05 mass%, 0.001 to 1 mass%, 0.001 to 0.1 mass%, 0.001 to 0.05 mass%, 0.003 to 1 mass%, 0.003 to 0.1 mass%, or 0.003 to 0.05 mass%.

[0033] The content of the phosphate compound may be in the following ranges relative to 100 parts by mass of abrasive grains. From the viewpoint of easily increasing the removal rate of the material to be polished, the content of the phosphate compound may be 0.1 parts by mass or more, 0.3 parts by mass or more, 0.5 parts by mass or more, 0.8 parts by mass or more, 1 part by mass or more, 1.2 parts by mass or more, 1.5 parts by mass or more, 1.8 parts by mass or more, or 2 parts by mass or more. From the viewpoint of easily suppressing aggregation of the abrasive grains, the content of the phosphate compound may be 50 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, 10 parts by mass or less, 8 parts by mass or less, 5 parts by mass or less, 4 parts by mass or less, 3 parts by mass or less, or 2 parts by mass or less. From these viewpoints, the content of the phosphate compound may be 0.1 to 50 parts by mass, 0.1 to 10 parts by mass, 0.1 to 5 parts by mass, 0.5 to 50 parts by mass, 0.5 to 10 parts by mass, 0.5 to 5 parts by mass, 1 to 50 parts by mass, 1 to 10 parts by mass, or 1 to 5 parts by mass.

[0034] The polishing liquid according to this embodiment may contain a polymer, if necessary. Examples of the polymer include homopolymers (e.g., polyacrylic acid) of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid; ammonium salts or amine salts of the homopolymers; copolymers of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid with monomers such as alkyl acrylates (e.g., methyl acrylate, ethyl acrylate), hydroxyalkyl acrylates (e.g., hydroxyethyl acrylate), alkyl methacrylates (e.g., methyl methacrylate, ethyl methacrylate), hydroxyalkyl methacrylates (e.g., hydroxyethyl methacrylate), styrene compounds (e.g., styrene, alkylstyrene, styrene sulfonic acid), vinyl acetate, and vinyl alcohol; and ammonium salts or amine salts of the copolymers. The polishing liquid according to this embodiment may contain a copolymer P having, as monomer units, at least one selected from the group consisting of acrylic acid and methacrylic acid and a styrene compound, or may contain a styrene / acrylic acid copolymer, in order to facilitate an increase in the polishing rate of the material to be polished.

[0035] The content of the styrene compound monomer units in copolymer P may be in the following ranges based on the entire copolymer P. From the viewpoint of easily increasing the removal rate of the material to be polished, the content of the styrene compound monomer units may be 10 mol% or more, 15 mol% or more, 20 mol% or more, 25 mol% or more, or 30 mol% or more. From the viewpoint of easily increasing the removal rate of the material to be polished, the content of the styrene compound monomer units may be 60 mol% or less, 55 mol% or less, 50 mol% or less, 45 mol% or less, 40 mol% or less, 35 mol% or less, or 30 mol% or less. From these viewpoints, the content of the styrene compound monomer units may be 10 to 60 mol%, 10 to 50 mol%, 10 to 40 mol%, 20 to 60 mol%, 20 to 50 mol%, 20 to 40 mol%, 30 to 60 mol%, 30 to 50 mol%, or 30 to 40 mol%.

[0036] From the viewpoint of easily increasing the removal rate of the material to be polished, the polymer content may be in the following ranges based on the total mass of the polishing liquid or the total mass of water. The polymer content may be 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, 0.12% by mass or more, 0.15% by mass or more, 0.18% by mass or more, or 0.2% by mass or more. The polymer content may be 10% by mass or less, 5% by mass or less, 3% by mass or less, 2% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, or 0.2% by mass or less. From these viewpoints, the content of the polymer may be 0.01 to 10 mass%, 0.01 to 1 mass%, 0.01 to 0.5 mass%, 0.05 to 10 mass%, 0.05 to 1 mass%, 0.05 to 0.5 mass%, 0.1 to 10 mass%, 0.1 to 1 mass%, or 0.1 to 0.5 mass%.

[0037] The polishing liquid according to this embodiment may contain an acid component (excluding compounds corresponding to phosphate compounds) as needed. Examples of the acid component include organic acids such as propionic acid and acetic acid (excluding compounds corresponding to amino acids), inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and boric acid, and amino acids such as glycine.

[0038] From the viewpoint of easily increasing the polishing rate of the material to be polished, the content of the acid component may be in the following ranges based on the total mass of the polishing liquid or the total mass of water. The content of the acid component may be 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, 0.12% by mass or more, 0.15% by mass or more, 0.18% by mass or more, or 0.2% by mass or more. The content of the acid component may be 10% by mass or less, 5% by mass or less, 3% by mass or less, 2% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, or 0.2% by mass or less. From these viewpoints, the content of the acid component may be 0.01 to 10 mass%, 0.01 to 1 mass%, 0.01 to 0.5 mass%, 0.05 to 10 mass%, 0.05 to 1 mass%, 0.05 to 0.5 mass%, 0.1 to 10 mass%, 0.1 to 1 mass%, or 0.1 to 0.5 mass%.

[0039] The polishing liquid according to this embodiment may contain components other than the abrasive grains, water, phosphate compound, polymer, and acid component according to this embodiment. Such components are not particularly limited, and may include cerium-free abrasive grains, basic compounds, etc.

[0040] The pH of the polishing liquid according to this embodiment may be in the following ranges, from the viewpoint of easily increasing the polishing rate of the material to be polished. The pH of the polishing liquid may be 1.0 or more, 1.5 or more, 2.0 or more, 2.5 or more, 3.0 or more, 3.5 or more, 4.0 or more, 4.5 or more, or 5.0 or more. The pH of the polishing liquid may be 8.0 or less, 7.5 or less, 7.0 or less, less than 7.0, 6.5 or less, 6.0 or less, or 5.5 or less. From these viewpoints, the pH of the polishing liquid may be 1.0 to 8.0, 1.0 to 7.0, 1.0 to 6.0, 3.0 to 8.0, 3.0 to 7.0, 3.0 to 6.0, 4.0 to 8.0, 4.0 to 7.0, or 4.0 to 6.0. The pH of the polishing liquid according to this embodiment can be measured by the method described in the Experimental Examples below.

[0041] The polishing method according to this embodiment includes a polishing step of polishing a member to be polished using the polishing liquid according to this embodiment (the polishing liquid obtained by the method for producing a polishing liquid according to this embodiment). In the polishing step, the surface to be polished of the member to be polished can be polished. In the polishing step, at least a portion of the material to be polished in the member to be polished can be polished and removed. Examples of the material to be polished include insulating materials such as silicon oxide. The member to be polished may contain silicon oxide. The member to be polished is not particularly limited and may be a wafer (e.g., a semiconductor wafer) or a chip (e.g., a semiconductor chip). The member to be polished may be a wiring board or a circuit board.

[0042] The component manufacturing method according to this embodiment includes a component fabrication step in which a component is obtained using a polished member polished by the polishing method according to this embodiment. The component according to this embodiment is a component obtained by the component manufacturing method according to this embodiment. The component according to this embodiment is not particularly limited and may be an electronic component (e.g., a semiconductor component such as a semiconductor package), a wafer (e.g., a semiconductor wafer), or a chip (e.g., a semiconductor chip). As one aspect of the component manufacturing method according to this embodiment, an electronic component is obtained using a polished member polished by the polishing method according to this embodiment. As one aspect of the component manufacturing method according to this embodiment, a semiconductor component (e.g., a semiconductor package) is obtained using a polished member polished by the polishing method according to this embodiment. The component manufacturing method according to this embodiment may include a polishing step in which a polished member is polished by the polishing method according to this embodiment before the component fabrication step.

[0043] The component manufacturing method according to this embodiment may include, as one aspect of the component manufacturing process, a singulation step of singulating a polished member polished by the polishing method according to this embodiment. The singulation step may be, for example, a step of dicing a wafer (e.g., a semiconductor wafer) polished by the polishing method according to this embodiment to obtain chips (e.g., semiconductor chips). As one aspect of the component manufacturing method according to this embodiment, the electronic component manufacturing method according to this embodiment may include a step of singulating a polished member polished by the polishing method according to this embodiment to obtain electronic components (e.g., semiconductor components). As one aspect of the component manufacturing method according to this embodiment, the semiconductor component manufacturing method according to this embodiment may include a step of singulating a polished member polished by the polishing method according to this embodiment to obtain semiconductor components (e.g., semiconductor packages).

[0044] The component manufacturing method according to this embodiment may include, as one aspect of the component manufacturing process, a connecting process for connecting (e.g., electrically connecting) a member to be polished that has been polished by the polishing method according to this embodiment to another object to be connected. The object to be connected to the member to be polished by the polishing method according to this embodiment is not particularly limited and may be the member to be polished by the polishing method according to this embodiment, or may be a different object to be connected from the member to be polished by the polishing method according to this embodiment. In the connecting process, the member to be polished and the object to be connected may be directly connected (connected in a state where the member to be polished and the object to be connected are in contact with each other), or the member to be polished and the object to be connected may be connected via another member (such as a conductive member). The connecting process may be performed before the singulation process, after the singulation process, or before or after the singulation process.

[0045] The connecting step may be a step of connecting a polished surface of a polished member polished by the polishing method according to this embodiment to a connected body, or a step of connecting a connecting surface of a polished member polished by the polishing method according to this embodiment to a connecting surface of a connected body. The connecting surface of the polished member may be a polished surface polished by the polishing method according to this embodiment. A connected body including a polished member and a connected body can be obtained by the connecting step. In the connecting step, if the connecting surface of the polished member has a metal portion, the connected body may be brought into contact with the metal portion. In the connecting step, if the connecting surface of the polished member has a metal portion and the connecting surface of the connected body has a metal portion, the metal portions may be brought into contact with each other. The metal portion may include, for example, copper.

[0046] The device according to this embodiment (for example, an electronic device such as a semiconductor device) comprises a polished member polished by the polishing method according to this embodiment and at least one selected from the group consisting of the parts according to this embodiment. [Example]

[0047] Hereinafter, the present disclosure will be specifically described based on experimental examples, but the present disclosure is not limited to these experimental examples.

[0048] (Preparation of cerium oxide particles) Cerium oxycarbonate was prepared from various manufacturers, and different cerium oxycarbonate was used in each experiment. The cerium oxycarbonate was calcined in an electric furnace at 800°C in air for 1 hour to obtain cerium oxide particles (ceria particles).

[0049] (Positron lifetime measurement of cerium oxide particles) The positron lifetime (average value, minor component value, and major component value) of the above-mentioned cerium oxide particles was measured by the following procedure. The measurement results are shown in Table 1.

[0050] The cerium oxide particles described above were packed into a powder measurement cell to a height of 5 mm, and positron lifetime (positron annihilation lifetime) measurements were performed using the positron annihilation method under the following conditions. Using the positron lifetime measurements, three-component and four-component analyses were performed, including the lifetimes and strengths of the Kapton and adhesive contained in the radiation source. The lifetimes of the Kapton contained in the radiation source, τ1 (three-component analysis) and τ1' (four-component analysis), were found to be 0.38 ns, which is close to the positron lifetime of the sample. Therefore, to accurately measure the positron lifetime of the sample, the intensities of the Kapton contained in the radiation source, I1 (three-component analysis) and I1' (four-component analysis), must be fixed. Since I1 and I1' are known to be approximately 20–35%, they were fixed at 30% in this measurement. τ2 (three-component analysis) and τ2' (four-component analysis) are the lifetimes of the adhesive contained in the radiation source, and the corresponding I2 (three-component analysis) and I2' (four-component analysis) indicate the strength of the adhesive contained in the radiation source. The lifetime derived from cerium oxides obtained in the three-component analysis was taken as the average positron lifetime (τ3), and the corresponding intensity was taken as I3 (I1+I2+I3=100%). In the four-component analysis, the annihilation lifetimes derived from cerium oxides were taken as τ3' and τ4' in order of decreasing order, with τ3' being the small component of the positron lifetime and τ4' being the large component of the positron lifetime, and the corresponding intensities were taken as I3' and I4' (I1'+I2'+I3'+I4'=100%).

[0051] {Measurement conditions} Measuring device: Manufactured by Toyo Seiko Co., Ltd., product name “PSA Type L-II” Positron source: Thin film positron source (manufactured by Japan Radioisotope Association) Total count: 1,000,000 counts

[0052] (Measurement of crystallite size of cerium oxide particles) Diffraction spectra of the above-mentioned cerium oxide particles were obtained in the 2θ range of 27–30° using a powder X-ray diffractometer (XRD, Rigaku Corporation, Ultima IV, divergence high-limiting slit 10 mm, divergence slit 1°, scattering slit 1°, absorber Cukβ, receiving slit 0.15 mm, output 40 kV / 20 mA). Measurements were performed at a measurement interval of 0.02° / step and a scan rate of 4 steps / s. The crystallite diameter (average value) was calculated from the half-width of the CeO2 (111) peak and the Scherrer equation. A Scherrer constant of 0.89 was used. The measurement results are shown in Table 1.

[0053] (Preparation of polishing solution) The cerium oxide particles, ammonium dihydrogen phosphate, and water were mixed to obtain a suspension. The content of the cerium oxide particles was 20 mass% based on the total mass of the suspension, and the content of the ammonium dihydrogen phosphate was 1 part by mass per 100 parts by mass of the cerium oxide particles.

[0054] The suspension was dispersed for 30 minutes using an ultrasonic disperser (manufactured by SND Corporation, trade name "US-105"), and then the cerium oxide particles in the suspension were pulverized (wet pulverized) using a wet atomizer (manufactured by Sugino Machine Corporation, trade name: Star Burst Labo, model number: HJP-25005) until the particle size reached approximately 200 nm.

[0055] After the above-mentioned grinding process, a classification process was carried out using a centrifuge (manufactured by Eppendorf-Himac Technologies, product name: CR-7) to remove coarse particles from the above-mentioned suspension and to make the particle size uniform to about 150 nm, thereby obtaining an aqueous dispersion of abrasive grains. The classification process was carried out by adding water to dilute the suspension to a cerium oxide particle content of 10 mass %, and then placing 400 g of the suspension in a centrifuge tube and centrifugation for 2600 to 2800 min. -1 This was done by centrifugation at 4°C for 5 minutes.

[0056] A polishing solution was obtained by mixing the aqueous dispersion with styrene / acrylic acid copolymer (manufactured by Toray Fine Chemicals Co., Ltd., product name: ASP-040, styrene monomer unit content: 30 mol%), acetic acid, and water. Based on the total mass of the polishing solution, the abrasive grain content was 0.5 mass%, the ammonium dihydrogen phosphate content was 0.005 mass%, the styrene / acrylic acid copolymer content was 0.2 mass%, and the acetic acid content was 0.1 mass%.

[0057] The pH of the polishing solution was measured using a pH meter (Horiba, Ltd., product name: LAQUA act D-71). After three-point calibration of the pH meter using three pH buffer solutions (pH 4.01, pH 6.86, and pH 9.18) as standard buffer solutions, the pH meter electrode was placed in the polishing solution, and the pH was measured three minutes after the pH had stabilized. The temperature of both the standard buffer solution and the polishing solution was 25°C, and the pH of the polishing solution in each experiment was 5.0.

[0058] A patterned wafer (manufactured by SEMATECH, product name: 12" SEMATECH764 (Stop on Nitride)) having SiO2 patterns and SiN patterns arranged alternately on a silicon substrate (12-inch diameter wafer) was prepared. This patterned wafer was obtained by forming a linear SiN pattern (thickness: 1500 nm) on a portion of the silicon substrate, then etching the silicon substrate in the portion without the SiN pattern by 350 nm to form linear recesses, and then forming a 600 nm thick silicon oxide portion on the SiN pattern and in the recesses. The patterned wafer has a pattern region where the line width (L / S; unit: μm) of the SiN pattern (line) and the SiO2 pattern (space) is 50 / 50.

[0059] In a polishing apparatus (Applied Materials, product name: Reflexion), the above-mentioned patterned wafer was attached to a substrate holder with an adsorption pad attached. The holder was placed on a platen with a polishing pad (Nitta DuPont, product name: IC1010) attached, with the silicon oxide portion facing the polishing pad. The above-mentioned polishing solution was supplied onto the polishing pad at a supply rate of 250 mL / min, while the patterned wafer was pressed against the polishing pad with a polishing load of 3 psi (1 psi = 6.9 kPa). The platen was then moved for 93 min. -1 , Holder 87min -1 The polishing was carried out for 60 seconds by rotating the wafer at 400°C. After polishing, the patterned wafer was thoroughly washed with pure water and then dried.

[0060] The polishing rate of silicon oxide was determined by measuring the change in thickness of SiO2 (one location) on SiN in the L / S = 50 / 50 pattern area before and after polishing using an optical interference film thickness measuring device (Nanometrics, product name: Nanospec AFT-5100). The results are shown in Table 1.

[0061] [Table 1]

Claims

1. A method for selecting particles to obtain abrasive grains, comprising the steps of: the particles comprise cerium; A method for selecting particles, wherein the particles are selected based on an average value of positron lifetime measured by positron annihilation.

2. The method of claim 1 , wherein the particles comprise cerium oxide.

3. A method for producing cerium-containing abrasive grains, comprising: A method for producing abrasive grains, comprising pulverizing particles selected by the particle selection method according to claim 1 or 2.

4. The method of claim 3 , wherein the abrasive grains comprise cerium oxide.

5. A method for producing a polishing liquid, comprising mixing the abrasive grains obtained by the method for producing abrasive grains according to claim 3 with water.

6. A polishing method, comprising polishing a workpiece with the polishing liquid obtained by the method for producing a polishing liquid according to claim 5.

7. The polishing method according to claim 6 , wherein the member to be polished comprises silicon oxide.

8. A method for manufacturing a part, comprising obtaining a part using a polished member polished by the polishing method according to claim 6.

9. A method for producing a semiconductor component, comprising obtaining a semiconductor component using a polished member polished by the polishing method according to claim 6.

10. Particles for obtaining abrasive grains, Contains cerium, Particles having an average positron lifetime of 330 ps or more as measured by positron annihilation.

11. The particles of claim 10 comprising cerium oxide.

Images