Polishing composition and polishing method using the same

Abstract

Provided is a means for being able to reduce the abrasive grain residue on the surface of an object to be polished after polishing. The polishing composition of the present invention is a polishing composition including abrasive grains and a dispersion medium, wherein the abrasive grains are silica particles having an average particle size (D50) larger than 1.0 μm and a primary particle circularity of 0.90 or more.

Description

[Technical Field]

[0001] The present invention relates to a polishing composition and a polishing method using the same. [Background technology]

[0002] Conventionally, various studies have been conducted on polishing compositions made of various materials containing resins.

[0003] JP 2016-183212 A discloses a polishing composition for polishing an object to be polished, which contains a resin having high rigidity and high strength. More specifically, JP 2016-183212 A discloses that a polishing composition containing abrasive grains having a Mohs hardness and surface acidity of a predetermined value or more and a dispersion medium can polish even a resin having high rigidity and high strength at a high polishing rate. JP 2016-183212 A also discloses that, from the viewpoint of polishing rate, abrasive grains mainly composed of α-alumina are preferred.

[0004] Japanese Patent Laid-Open No. 2007-063442 discloses a polishing composition for polishing synthetic resin objects. More specifically, Japanese Patent Laid-Open No. 2007-063442 discloses that by using a polishing composition containing a polyurethane polymer surfactant with a specific structure and having a predetermined viscosity range, it is possible to suppress the decrease in polishing ability when polishing synthetic resins. Furthermore, Japanese Patent Laid-Open No. 2007-063442 also discloses that, from the viewpoint of polishing speed, it is preferable that the polishing composition further contains α-alumina as abrasive grains. Summary of the Invention

[0005] However, there is still room for improvement in the polishing rate.

[0006] Therefore, the present invention has been made in consideration of the above circumstances, and has an object to provide a means for improving the polishing rate of an object to be polished (particularly an object to be polished that contains a resin and a filler).

[0007] The present inventors have conducted extensive research to solve the above problems, and as a result, have found that the above problems can be solved by using silica particles having a specific particle size and circularity as abrasive grains, thereby completing the present invention.

[0008] That is, the above-mentioned problems of the present invention can be solved by the following means.

[0009] A polishing composition comprising abrasive grains and a dispersion medium, wherein the abrasive grains have an average particle diameter (D 50 ) is greater than 1.0 μm and the circularity of the primary particles is 0.90 or more.

[0010] Hereinafter, embodiments of the present invention will be described. Note that the present invention is not limited to the following embodiments and can be modified in various ways within the scope of the claims. Throughout this specification, singular expressions should be understood to include the plural concept unless otherwise specified. Therefore, singular articles (e.g., "a," "an," "the," etc. in English) should be understood to include the plural concept unless otherwise specified. Furthermore, terms used in this specification should be understood to have the meaning commonly used in the relevant field unless otherwise specified. Therefore, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the case of conflict, the present specification (including definitions) will prevail.

[0011] In this specification, the range "X to Y" includes X and Y and means "X or more and Y or less." Unless otherwise specified, operations and measurements of physical properties are performed at room temperature (20°C or more and 25°C or less) and at a relative humidity of 40% RH or more and 50% RH or less.

[0012] <Polishing composition> One aspect of the present invention is a polishing composition comprising abrasive grains and a dispersion medium, wherein the abrasive grains have an average particle diameter (D 50The present invention relates to a polishing composition comprising silica particles having a particle size (particle diameter) of greater than 1.0 μm and a primary particle circularity of 0.90 or more. According to the present invention, the polishing rate of an object to be polished (particularly an object to be polished containing a resin and a filler) can be improved. By using silica particles having the above-mentioned specific particle size and circularity as abrasive grains, the polishing rate of an object to be polished (particularly an object to be polished containing a resin and a filler) can be improved. Abrasive grain residue on the surface of an object to be polished (particularly an object to be polished containing a resin and a filler) after polishing can be reduced. When polishing an object to be polished (particularly an object to be polished containing a resin and a filler), a good balance can be achieved between a high polishing rate and minimal abrasive grain residue on the surface after polishing.

[0013] The polishing composition of the present invention is typically supplied to a polishing object in the form of a polishing liquid containing the polishing composition and used to polish the object. The polishing composition of the present invention may be used as a polishing liquid after dilution (typically with water), or may be used as a polishing liquid as is. That is, the concept of the polishing composition in the technology of the present invention encompasses both a polishing composition (working slurry) that is supplied to a polishing object and used to polish the object, and a concentrated liquid (raw solution of working slurry) that is diluted and used for polishing. The concentration ratio of the concentrated liquid can be, for example, about 2 to 100 times on a volume basis, and is usually about 5 to 50 times.

[0014] [Abrasive grain] <Silica particles> The abrasive grains contained in the polishing composition of the present invention have an average particle diameter (D 50 ) and a primary particle circularity of 0.90 or more. In this specification, unless otherwise specified, the abrasive grains are silica particles having an average particle diameter (D 50 ) and a primary particle circularity of 0.90 or more are also simply referred to as "silica particles according to the present invention" or "silica particles".

[0015] In one embodiment of the present invention, both dry silica particles and wet silica particles are preferably used as the silica particles. The silica particles can be easily produced by appropriately referring to known production methods. In addition, the silica particles have an average particle diameter (D 50 ) and the circularity of the primary particles are satisfied, commercially available products may be used. Methods for producing dry silica particles include the flame hydrolysis method, the deflagration method, and the fusion method. Methods for producing wet silica particles (particularly colloidal silica particles) include the sodium silicate method, the alkoxide method, and the sol-gel method. Regardless of the method used, the silica particles produced by any of these methods can be used in accordance with the average particle diameter (D 50 As long as the above requirements are met, the silica particles of the present invention can be suitably used. Among these silica particles, dry silica particles are particularly preferred. Furthermore, the preferred methods for producing the dry silica particles are the deflagration method and the melting method.

[0016] In one embodiment, the raw silica particles are silica particles obtained by a sodium silicate method, which is a method of growing particles from activated silicic acid, typically obtained by ion-exchanging an aqueous solution of an alkali silicate such as water glass, as a raw material.

[0017] In one embodiment, the raw silica particles are silica particles obtained by the alkoxide method, which typically uses alkoxysilane as a raw material and subjects it to a hydrolysis and condensation reaction.

[0018] In one embodiment, the raw silica particles are obtained by a vaporized metal combustion (VMC) method. The VMC method is a method of producing silica particles by burning a combustion enhancer (such as a hydrocarbon gas) with a burner in an oxygen-containing atmosphere to form a chemical flame, adding metallic silica to the chemical flame in an amount sufficient to form a dust cloud, and causing a deflagration.

[0019] In one embodiment, the raw silica particles are obtained by a fusion method, which involves introducing silica into a flame, melting it, and then cooling it to obtain silica particles.

[0020] The type of silica particles used is not particularly limited, but for example, surface-modified silica particles can be used. For example, the silica particles may have a cationic group. Preferred examples of silica particles having a cationic group include silica particles with an amino group fixed to the surface. Examples of methods for producing silica particles having such cationic groups include those described in Japanese Patent Laid-Open No. 2005-162533, in which a silane coupling agent having an amino group, such as aminoethyltrimethoxysilane, aminopropyltrimethoxysilane, aminoethyltriethoxysilane, aminopropyltriethoxysilane, aminopropyldimethylethoxysilane, aminopropylmethyldiethoxysilane, or aminobutyltriethoxysilane, is fixed to the surface of abrasive grains. This allows silica particles with an amino group fixed to the surface (amino group-modified silica particles) to be obtained.

[0021] Silica particles may have anionic group.Preferably, as the silica particles having anionic group, the silica particles that have anionic group such as carboxylic acid group, sulfonic acid group, phosphonic acid group, aluminic acid group, etc. fixed on the surface.The method for producing the silica particles having such anionic group is not particularly limited, and for example, the method of reacting the silane coupling agent having anionic group at the end with silica particles can be mentioned.

[0022] As a specific example, sulfonic acid groups can be immobilized on silica particles by the method described in "Sulfonic acid-functionalized silica through thiol groups," Chem. Commun. 246-247 (2003). Specifically, a silane coupling agent having a thiol group, such as 3-mercaptopropyltrimethoxysilane, is coupled to silica particles, and then the thiol group is oxidized with hydrogen peroxide to obtain silica particles having sulfonic acid groups immobilized on the surface.

[0023] Alternatively, to immobilize carboxylic acid groups on silica particles, this can be achieved by, for example, the method described in "Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel," Chemistry Letters, 3, 228-229 (2000). Specifically, silica particles having carboxylic acid groups immobilized on their surfaces can be obtained by coupling a silane coupling agent containing a photolabile 2-nitrobenzyl ester to silica particles and then irradiating the particles with light.

[0024] The average particle diameter (D 50 ) is larger than 1.0 μm. Usually, the polishing rate tends to increase in proportion to the increase in the average particle diameter of the abrasive grains. The inventors of the present invention have conducted various studies on the size of silica particles and have surprisingly found that the polishing rate increases almost in proportion to the average particle diameter up to an average particle diameter of 1.0 μm, but the polishing rate increases significantly above 1.0 μm. Here, the average particle diameter (D 50 If the average particle diameter (D) of the silica particles is 1.0 μm or less, the polishing rate is insufficient. 50) is preferably greater than 1.2 μm, more preferably 1.5 μm or more, and particularly preferably 1.8 μm or more. 50 ) is preferably 20 μm or less, more preferably less than 10.0 μm, and particularly preferably less than 7.0 μm. In particular, the average particle diameter (D 50 When the average particle diameter (D) of the silica particles is less than 10.0 μm (particularly less than 7.0 μm), a high polishing rate can be maintained while the abrasive grain residue can be more effectively reduced. 50 A preferred example of the particle diameter is preferably more than 1.2 μm and not more than 20 μm, more preferably 1.5 μm or more and less than 10.0 μm, and particularly preferably 1.8 μm or more and less than 7.0 μm. Within the above range, the polishing speed of the object to be polished (particularly the object to be polished containing a resin and a filler) can be improved. In addition, the abrasive grain residue on the surface of the object to be polished (particularly the object to be polished containing a resin and a filler) after polishing can be reduced, and a better balance can be achieved between an improved polishing speed and a reduced abrasive grain residue. Furthermore, within this range, a smaller particle diameter is more suitable for reducing abrasive grain residue, and a larger particle diameter is more suitable for improving the polishing speed. The average particle diameter (average secondary particle diameter) of silica particles is the particle diameter (D) at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution reaches 50%. 50 ) where the average particle diameter of the silica particles (D 50 ) can be determined by dynamic light scattering, laser diffraction, laser scattering, or pore electrical resistance, etc. Specifically, the value determined by the measurement method described in the Examples below is used.

[0025] The circularity of the primary particles of silica particles, which are abrasive grains contained in the polishing composition of the present invention (hereinafter simply referred to as "circularity"), is 0.90 or more. If the circularity of the primary particles of silica particles is less than 0.90, the abrasive grains may remain stuck on the surface of the object to be polished due to the unevenness of the surface, resulting in an excessive increase in abrasive grain residue on the surface after polishing (Comparative Examples 1 to 3 below). The circularity of the primary particles of silica particles is preferably 0.92 or more, more preferably 0.95 or more, and particularly preferably greater than 0.95. A preferred example of the circularity of the primary particles of silica particles is preferably 0.92 to 1.00, more preferably 0.95 to 1.00, and particularly preferably greater than 0.95 to 1.00. Within the above range, the polishing rate of the object to be polished (particularly an object to be polished containing a resin and a filler) can be improved. Furthermore, it is possible to reduce abrasive grain residue on the surface of the polished object (especially an object containing resin and filler) after polishing, thereby achieving a better balance between improving the polishing rate and reducing abrasive grain residue.In this specification, the circularity of the primary particles of the silica particles is determined to three decimal places using the method described in the Examples below, and the value obtained by rounding off the three decimal places is used.The closer the circularity is to 1 (1.00), the closer it is to a perfect sphere, and therefore, the closer the circularity is to 1 (1.00), the higher the proportion of particles that are nearly spherical in the silica particles.The use of particles that are more nearly spherical as abrasive grains may make it easier to achieve the above-mentioned effects.

[0026] In one embodiment, the silica particles have a modified Mohs hardness of 5 to 9. Such a hardness allows for a better balance between an improvement in the removal rate and a reduction in abrasive grain residue.

[0027] The silica particles may be used alone or in combination of two or more kinds.

[0028] The concentration (content) of silica particles in the polishing composition of the present invention is not particularly limited. In the case of a polishing composition that is used as a polishing liquid for polishing a polishing object as is (typically a slurry-like polishing liquid, sometimes referred to as a working slurry or polishing slurry), the concentration (content) of silica particles is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably more than 1% by mass, and particularly preferably 2% by mass or more, based on the total mass of the polishing composition. The higher the concentration of silica particles, the more improved the polishing rate. Furthermore, the concentration (content) of silica particles is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably less than 10% by mass, and particularly preferably 8% by mass or less, based on the total mass of the polishing composition. Within the above range, the occurrence of defects such as abrasive grain residue is further reduced. A preferred example of the concentration (content) of silica particles is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, even more preferably more than 1% by mass or more and 10% by mass or less, and particularly preferably 2% by mass or more and 8% by mass or less, based on the total mass of the polishing composition. Within the above range, the polishing rate of the object to be polished (particularly an object to be polished containing a resin and a filler) can be improved. Furthermore, the amount of abrasive residue on the surface of the object to be polished (particularly an object to be polished containing a resin and a filler) after polishing can be reduced, resulting in a better balance between improved polishing rate and reduced abrasive residue. When two or more types of silica particles are used, the concentration (content) of the silica particles refers to the total amount of all silica particles.

[0029] Furthermore, in the case of a polishing composition that is diluted and used for polishing (i.e., a concentrate or a raw solution for a working slurry), the content of silica particles is usually appropriate to be 30% by mass or less, and more preferably 25% by mass or less, from the viewpoints of storage stability, filterability, etc. Furthermore, from the viewpoint of utilizing the advantages of forming a concentrate, the content of abrasive grains is preferably 1% by mass or more, more preferably 5% by mass or more.

[0030] The abrasive grains are essentially of average particle diameter (D 50 ) is greater than 1.0 μm and the circularity of the primary particles is 0.90 or more (silica particles according to the present invention). Here, "the abrasive grains are substantially composed of silica particles according to the present invention" means that the total content of silica particles contained in the polishing composition is greater than 99% by mass (upper limit: 100% by mass) of the total content of abrasive grains contained in the polishing composition. Preferably, the abrasive grains are composed only of silica particles according to the present invention (the total content of the silica particles according to the present invention is 100% by mass of all the abrasive grains).

[0031] [Dispersion medium] The polishing composition of the present invention contains a dispersion medium that disperses or dissolves each component.

[0032] The dispersion medium preferably contains water.Furthermore, from the viewpoint of preventing the influence of impurities on other components of the polishing composition, it is preferable to use water with as high purity as possible.Specifically, it is preferable to use pure water or ultrapure water, which has been removed impurity ions by ion exchange resin and then filtered to remove foreign matter, or distilled water.Furthermore, the dispersion medium may further contain an organic solvent or the like for the purpose of controlling the dispersibility of other components of the polishing composition.

[0033] [pH adjuster] The polishing composition according to one embodiment of the present invention preferably further contains a pH adjuster, which can contribute to adjusting the pH of the polishing composition by selecting the type and amount of the pH adjuster.

[0034] The pH adjuster is not particularly limited as long as it is a compound having a pH adjusting function, and known compounds can be used. The pH adjuster is not particularly limited as long as it is a compound having a pH adjusting function, and examples thereof include acids and alkalis.

[0035] The acid may be either inorganic or organic. Inorganic acids include, but are not limited to, sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. Organic acids include, but are not limited to, carboxylic acids such as 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid, as well as methanesulfonic acid, ethanesulfonic acid, and isethionic acid. Among these, organic acids are preferred, and 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), malic acid, citric acid, and maleic acid are more preferred. When inorganic acids are used, nitric acid, sulfuric acid, and phosphoric acid are preferred.

[0036] The alkali is not particularly limited, but examples thereof include alkali metal hydroxides such as potassium hydroxide, ammonia, quaternary ammonium salts such as tetramethylammonium and tetraethylammonium, amines such as ethylenediamine and piperazine, etc. Among these, potassium hydroxide and ammonia are preferred.

[0037] The pH adjusters may be used alone or in combination of two or more.

[0038] The content of the pH adjuster is not particularly limited, and is preferably an amount that allows the pH value to be adjusted to a value within the preferred range described below.

[0039] [Redispersant] The polishing composition according to one embodiment of the present invention preferably further comprises a redispersant (a redispersant for abrasive grain precipitates). The use of the redispersant can facilitate redispersion of the polishing composition after storage. Therefore, it is advantageous in terms of handling the polishing composition.

[0040] Redispersant is not particularly limited as long as it is a compound that can easily redisperse the polishing composition after storage, and can use known compounds.Specifically, there are organic redispersants such as crystalline cellulose, sodium polyacrylate, polyacrylic acid (PAA), hydroxyethyl cellulose (HEC), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol (PEG), etc.; inorganic redispersants such as alumina sol, layered silicate, silica sol, etc., whose average particle size is less than 1.0 μm (particularly less than 0.2 μm).Among these, organic redispersants are preferred, and crystalline cellulose and sodium polyacrylate are more preferred.

[0041] That is, in one embodiment of the present invention, the redispersion agent includes an organic redispersion agent. In one embodiment of the present invention, the redispersion agent includes at least one of crystalline cellulose and sodium polyacrylate. In one embodiment of the present invention, the redispersion agent is at least one of crystalline cellulose and sodium polyacrylate.

[0042] Alternatively, at least one phosphorus-containing acid selected from the group consisting of phosphoric acid and its condensates, organic phosphoric acid, phosphonic acid, and organic phosphonic acid may be used as the redispersing agent. In this specification, "organic phosphoric acid" refers to an organic compound having at least one phosphoric acid group (-OP(=O)(OH)2), and "organic phosphonic acid" refers to an organic compound having at least one phosphonic acid group (-P(=O)(OH)2). In this specification, "phosphoric acid and its condensates, and organic phosphoric acid" are also referred to simply as "phosphoric acid-based acids," and "phosphonic acid and organic phosphonic acid" are also referred to simply as "phosphonic acid-based acids."

[0043] Specific examples of phosphorus-containing acids include phosphoric acid (orthophosphoric acid), pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, hexametaphosphoric acid, methyl acid phosphate, ethyl acid phosphate, ethyl glycol acid phosphate, isopropyl acid phosphate, phytic acid (myo-inositol-1,2,3,4,5,6-hexaphosphate), nitrilotris(methylenephosphonic acid) (NTMP), ethylenediaminetetra(methylenephosphonic acid) (EDTMP), diethylenetriaminepenta(methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, ethanehydroxy-1,1,2-triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid, and methanehydroxyphosphonic acid. Among these, from the viewpoint of achieving a good balance between redispersibility, polishing rate, and etching rate, phosphonic acids are preferred, organic phosphonic acids are more preferred, and 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), nitrilotris(methylenephosphonic acid) (NTMP), and ethylenediaminetetra(methylenephosphonic acid) (EDTMP) are even more preferred. The phosphorus-containing acid may be used alone or in combination of two or more. The phosphorus-containing acid may also function as the pH adjuster.

[0044] The redispersing agents may be used alone or in combination of two or more.

[0045] The concentration (content) of the redispersant in the polishing composition of the present invention is not particularly limited and can be appropriately selected depending on the desired redispersibility of the polishing composition after storage. In the case of a polishing composition that is used as a polishing liquid directly for polishing a polishing object (typically a slurry-like polishing liquid, sometimes referred to as a working slurry or polishing slurry), the concentration (content) of the redispersant is preferably 0.1 mass% or more, and even more preferably more than 0.3 mass%, relative to the total mass of the polishing composition. Furthermore, the concentration (content) of the redispersant is preferably 5 mass% or less, and more preferably 1 mass% or less, relative to the total mass of the polishing composition. A preferred example of the concentration (content) of the redispersant is preferably 0.1 mass% or more and 5 mass% or less, more preferably more than 0.3 mass% and 5 mass% or less, and even more preferably more than 0.3 mass% and 1 mass% or less, relative to the total mass of the polishing composition. Within the above range, the polishing composition can be easily redispersed after storage. When two or more redispersants are used, the concentration (content) of the redispersant refers to the total amount of all the redispersants.

[0046] In addition, in the case of a polishing composition that is diluted and used for polishing (i.e., a concentrate, a raw solution of a working slurry), the concentration (content) of the redispersant is usually 20% by mass or less, and more preferably 10% by mass or less. In addition, from the viewpoint of utilizing the advantages of a concentrate, the content of abrasive grains is preferably 1% by mass or more, more preferably 3% by mass or more.

[0047] [Other ingredients] The polishing composition of the present invention may further contain known components such as abrasive grains, chelating agents, thickeners, oxidizing agents, dispersants, surface protective agents, wetting agents, surfactants, anticorrosives (rust inhibitors), preservatives, and antifungal agents, other than those described above, within the range that does not impair the effects of the present invention. The contents of other components may be appropriately set depending on the purpose of their addition.

[0048] In one embodiment of the present invention, the polishing composition of the present invention has an average particle diameter (D 50) and silica particles having a primary particle circularity of 0.90 or more (silica particles according to the present invention), a dispersion medium and a redispersant, and at least one of a pH adjuster and an antifungal agent.

[0049] In one embodiment of the present invention, the polishing composition of the present invention has an average particle diameter (D 50 ) and a primary particle circularity of 0.90 or more (silica particles according to the present invention), a dispersion medium, a redispersant, and at least one of a pH adjuster and an anti-fungal agent. Here, "substantially composed of silica particles according to the present invention, a dispersion medium, a redispersant, and at least one of a pH adjuster and an anti-fungal agent" means that the total content of the silica particles, dispersion medium, redispersant, pH adjuster, and anti-fungal agent exceeds 98% by mass, preferably exceeds 99% by mass (upper limit: 100% by mass), relative to the polishing composition. That is, in the above embodiment, the polishing composition according to the present invention is a polishing composition having an average particle diameter (D 50 ) and silica particles having a primary particle circularity of 0.90 or more (silica particles according to the present invention), a dispersion medium and a redispersant, and at least one of a pH adjuster and an anti-mold agent, and the total content of the silica particles, the dispersion medium and redispersant, and at least one of a pH adjuster and an anti-mold agent is more than 98% by mass and less than 100% by mass (preferably more than 99% by mass and less than 100% by mass) or 100% by mass relative to the polishing composition.

[0050] In one embodiment of the present invention, the polishing composition according to the present invention is a polishing composition (typically a slurry-like polishing liquid, sometimes referred to as a working slurry or a polishing slurry) that is used as a polishing liquid as it is for polishing an object to be polished, and has an average particle diameter (D 50) and silica particles having a primary particle circularity of 0.90 or more (silica particles according to the present invention), a dispersion medium, a redispersant, a pH adjuster, and at least one additional component selected from the group consisting of a chelating agent, a thickener, an oxidizing agent, a dispersant, a surface protective agent, a wetting agent, a surfactant, an anticorrosive (rust inhibitor), an antiseptic, and an antifungal agent, and the content of the additional component is 0% by mass or more and 2% by mass or less relative to the polishing composition.

[0051] In one embodiment of the present invention, the polishing composition of the present invention is a polishing composition (i.e., a concentrated solution, a raw solution of a working slurry) that is diluted and used for polishing, and has an average particle diameter (D 50 ) and silica particles having a primary particle circularity of 0.90 or more (silica particles according to the present invention), a dispersion medium, a redispersant, a pH adjuster, and at least one additional component selected from the group consisting of a chelating agent, a thickener, an oxidizing agent, a dispersant, a surface protective agent, a wetting agent, a surfactant, an anticorrosive (rust inhibitor), an antiseptic, and an antifungal agent, and the content of the additional component is 0% by mass or more and 10% by mass or less relative to the polishing composition.

[0052] [pH] In the case of a polishing composition that is used as a polishing liquid for polishing an object to be polished as it is, the pH of the polishing composition according to this embodiment is preferably 2.0 or more and 7.0 or less, more preferably more than 2.0 and less than 5.0, and even more preferably 2.5 or more and less than 4.0. Within the above range, it is possible to achieve a better balance between improving the polishing rate and reducing the abrasive grain residue. In this specification, the pH of the polishing composition is determined by the measurement method described in the Examples below.

[0053] In the case of a polishing composition that is diluted before use in polishing (i.e., a concentrated solution), the pH of the polishing composition is suitably 2.5 or higher, preferably greater than 2.5, and more preferably 3.0 or higher. The pH of the polishing composition is suitably 7.5 or lower, preferably less than 5.5, and more preferably less than 4.5.

[0054] <Method for producing polishing composition> The manufacturing method (preparation method) of the polishing composition is not particularly limited, and for example, a manufacturing method including preparing silica particles having the above-mentioned specific average particle diameter and circularity, stirring and mixing a dispersion medium (preferably water) and, if necessary, a redispersant and / or other components, can be appropriately adopted. That is, another aspect of the present invention is a manufacturing method including preparing silica particles having the above-mentioned specific average particle diameter and circularity, stirring and mixing the dispersion medium (preferably water) and, if necessary, a redispersant and / or other components, 50 The method for producing a polishing composition comprises selecting silica particles as abrasive grains having a diameter greater than 1.0 μm and a primary particle circularity of 0.90 or more, and mixing the silica particles with a dispersion medium. Note that the silica particles, dispersion medium, redispersant, and other components are the same as those described above in the section on <Polishing Composition>, and therefore further description thereof will be omitted here.

[0055] In one embodiment of the present invention, the average particle size (D 50 Silica particles having an average particle diameter (D ) of more than 1.0 μm and a primary particle circularity of 0.90 or more can be obtained by selecting silica particles that satisfy the above-mentioned specific conditions from commercially available silica particles. In one embodiment of the present invention, 50 Silica particles having an average particle diameter (D ) of more than 1.0 μm and a primary particle circularity of 0.90 or more can be obtained by producing silica particles under conditions that satisfy the above-mentioned specific conditions. In one embodiment of the present invention, 50 Silica particles having a diameter greater than 1.0 μm and a primary particle circularity of 0.90 or more can be obtained by controlling silica particles that do not satisfy the above-mentioned specific conditions so that they satisfy the above-mentioned specific conditions. In this case, known methods can be used as the control method, either in the same manner or with appropriate modifications. For example, in the case of the deflagration method, methods such as controlling the particle size, supply rate, and mixing ratio with oxygen of the metallic silicon can be applied.

[0056] A polishing composition is prepared by stirring and mixing the silica particles selected as abrasive grains as described above with a dispersion medium (preferably water) and, if necessary, a redispersant and / or other components. The order in which the components are mixed is not particularly limited. For example, when the polishing composition contains silica particles, a dispersion medium, and a redispersant, the silica particles, dispersion medium, and redispersant are added all at once, and a pH adjuster is added, if necessary, to adjust the pH; the silica particles and redispersant are added to the dispersion medium, and a pH adjuster is added, if necessary, to adjust the pH; the silica particles and redispersant are added to the dispersion medium in this order, and a pH adjuster is added, if necessary, to adjust the pH; the redispersant and silica particles are added to the dispersion medium in this order, and a pH adjuster is added, if necessary, to adjust the pH; and the redispersant and silica particles are added to the dispersion medium in this order, and a pH adjuster is added, if necessary, to adjust the pH. The temperature at which the components are stirred and mixed is not particularly limited, but is preferably 10 to 40°C. Heating may be used to increase the dissolution rate. The mixing time is also not particularly limited.

[0057] <Object to be polished> The object to be polished with the polishing composition of the present invention is not particularly limited. Preferably, the object to be polished contains a resin and a filler. That is, in a preferred embodiment of the present invention, the polishing composition is used to polish an object to be polished containing a resin and a filler. When the polishing composition of the present invention is used with the specific silica particles as abrasives to polish an object to be polished containing a resin and a filler, polishing proceeds by simultaneously stripping off the filler and the surrounding resin, thereby achieving a specifically high polishing rate compared to other polishing abrasives. Furthermore, when simultaneously polishing a resin portion containing a filler and a metal portion such as copper, penetration of the abrasive particles into the metal surface can be suppressed or prevented (damage to the metal can be suppressed or prevented), i.e., abrasive residue on the surface after polishing can be reduced. Therefore, when polishing an object to be polished containing a resin and a filler, both a high polishing rate and low abrasive residue on the surface after polishing can be achieved. On the other hand, when alumina particles (ground alumina particles), which are commonly used in polishing, are used as abrasives, polishing proceeds by sequentially scraping off the filler and resin from the surface. Furthermore, when a resin part containing a filler and a metal part such as copper are polished simultaneously, the abrasive grains are likely to pierce the metal part, which means that the amount of abrasive grain residue on the polished surface is likely to increase.

[0058] Hereinafter, an embodiment in which the object to be polished contains a resin and a filler will be described in detail, but the present invention is not limited to the following embodiment.

[0059] Here, the resin is not particularly limited, but examples thereof include acrylic resins such as polymethyl(meth)acrylate, methyl methacrylate-methyl acrylate copolymer, and urethane(meth)acrylate resin; epoxy resin; olefin resin such as ultra-high molecular weight polyethylene (UHPE); phenolic resin; polyamide resin (PA); polyimide resin (PI); polyester resin such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and unsaturated polyester resin; polycarbonate resin (PC); polyphenylene sulfide resin; polystyrene resin such as syndiotactic polystyrene (SPS); polynorbornene resin; polybenzoxazole (PBO); polyacetal (POM); modified polyphenylene ether (m-PPE); amorphous polyarylate (PAR); polysulfone (PSF); polyethersulfone (PES); polyphenylene sulfide (PPS); polyetheretherketone (PEEK); polyetherimide (PEI); fluororesin; and liquid crystal polymer (LCP). In this specification, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid, as well as both acrylic acid and methacrylic acid. Similarly, in this specification, "(meth)acrylate" refers to acrylate or methacrylate, as well as both acrylate and methacrylate. Of these, from the viewpoint of processability, it is preferable that the resin has a cyclic molecular structure. That is, in a preferred embodiment of the present invention, the resin has a cyclic molecular structure. As resins having such a cyclic molecular structure, epoxy resins, polycarbonate resins, and polyphenylene sulfide resins are preferably used. The above resins can be used alone or in combination of two or more. The above resins may also be cured with a curing agent.

[0060] Furthermore, the material constituting the filler is not particularly limited, and examples thereof include glass, carbon, calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, titanium oxide, alumina, zinc oxide, silica (silicon dioxide), kaolin, talc, glass beads, sericite activated clay, bentonite, aluminum nitride, polyester, polyurethane, rubber, etc. Among these, from the viewpoint of processability, glass and silica are preferred, and silica is particularly preferred.

[0061] Examples of the shape of the filler include powder, sphere, fiber, and needle. Of these, from the viewpoint of processability, spherical and fibrous shapes are preferred, with spherical shapes being more preferred. The size of the filler is not particularly limited. For example, when the filler is spherical, the average particle diameter is, for example, 0.01 to 50 μm, preferably 1.0 to 6.5 μm. Here, the average particle diameter of the filler is determined by randomly selecting 200 fillers from an image of the object to be polished taken with a scanning electron microscope (SEM) (manufactured by Hitachi High-Tech Corporation, product name: SU8000), measuring the particle diameter of each, and averaging these values. Furthermore, when the filler is fibrous, the average major axis is, for example, 100 to 300 μm, preferably 150 to 250 μm, and the average minor axis is, for example, 1 to 30 μm, preferably 10 to 20 μm. Here, the average major axis and the average minor axis of the filler are determined by randomly selecting 200 fillers from an image of the object to be polished taken with a scanning electron microscope (SEM) (manufactured by Hitachi High-Tech Corporation, product name: SU8000), measuring the major axis and minor axis of each, and averaging these values ​​to obtain the average major axis (μm) and the average minor axis (μm), respectively.

[0062] The silica particles as abrasive grains and the filler may be in any combination, but it is preferable that the size (average particle diameter) of the silica particles as abrasive grains is larger than the size (average particle diameter) of the filler. That is, in a preferred embodiment of the present invention, when the object to be polished contains a resin and a filler, the average particle diameter (D 50) is larger than the average particle size of the filler. In the above embodiment, the relationship between the size of the silica particles and the size of the filler is not particularly limited, but the ratio of the average particle size of the abrasive grains to the average particle size of the filler (D 50 ) is preferably more than 1 and not more than 15, more preferably 1.5 or more and less than 10.0, and even more preferably more than 1.6 and less than 7.0. In the above, the average particle size of the filler means the average particle size when the filler is spherical, and means the average minor axis when the filler is fibrous.

[0063] The above fillers can be used alone or in combination of two or more.

[0064] Furthermore, the polishing object may contain, as a polishing surface, materials other than the resin and filler, such as copper (Cu), aluminum (Al), tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titanium nitride (TiN), nickel (Ni), ruthenium (Ru), cobalt (Co), tungsten (W), and tungsten nitride (WN).

[0065] The polishing target may be prepared from resin and filler, or may be prepared using commercially available products, such as the interlayer insulating material "Ajinomoto Build-up Film" (ABF) GX13, GX92, GX-T31, and GZ41 (all from Ajinomoto Fine-Techno Co., Ltd.), the glass fiber-reinforced polycarbonate (PC) resin "Panlite®" (all from Teijin Limited), GF-reinforced DURAFIDE® PPS, and GF / inorganic filler-reinforced DURAFIDE® PPS (all from Polyplastics Co., Ltd.).

[0066] <Polishing method> Another aspect of the present invention relates to a polishing method comprising a step of polishing an object to be polished using the above-mentioned polishing composition. Preferred examples of the object to be polished according to this aspect are the same as those described in the description of the <object to be polished>. For example, it is preferable to polish an object to be polished that contains a resin and a filler on the polishing surface. That is, a preferred aspect of the polishing method according to the present invention comprises a step of polishing an object to be polished that contains a resin and a filler using the above-mentioned polishing composition.

[0067] Polishing an object to be polished using a polishing composition can be carried out using equipment and conditions commonly used for polishing. Common polishing equipment includes single-sided polishing equipment and double-sided polishing equipment. In single-sided polishing equipment, the object to be polished is generally held using a holder called a carrier, and while a polishing composition is supplied from above, a platen with a polishing pad attached is pressed against one side of the object to be polished and the platen is rotated to polish one side of the object to be polished. In double-sided polishing equipment, the object to be polished is generally held using a holder called a carrier, and while a polishing composition is supplied from above, a platen with a polishing pad attached is pressed against the opposite side of the object to be polished, and the plates are rotated in relative directions to polish both sides of the object to be polished. During this process, polishing is achieved by the physical action of friction between the polishing pad and polishing composition and the object to be polished, and the chemical action of the polishing composition on the object to be polished. Porous materials such as nonwoven fabrics, polyurethane, and suede can be used as the polishing pad without any particular restrictions. It is preferable that the polishing pad be treated to allow the polishing liquid to accumulate.

[0068] Examples of polishing conditions include polishing load, platen rotation speed, carrier rotation speed, flow rate of polishing composition, and polishing time. There are no particular limitations on these polishing conditions. However, for example, the polishing load is preferably 0.1 psi (0.69 kPa) or more and 10 psi (69 kPa) or less per unit area of ​​the object to be polished, more preferably 0.5 psi (3.5 kPa) or more and 8.0 psi (55 kPa) or less, and even more preferably 1.0 psi (6.9 kPa) or more and 6.0 psi (41 kPa) or less. Generally, the higher the load, the higher the frictional force caused by the abrasive grains, improving the mechanical processing force and increasing the polishing rate. Within this range, a sufficient polishing rate can be achieved, and damage to the object to be polished due to the load and the occurrence of defects such as scratches on the surface can be suppressed. The platen rotation speed and carrier rotation speed are preferably 10 rpm (0.17 s -1 )~500rpm(8.3s -1 ) is preferable. The supply amount of the polishing composition is only required to be a supply amount (flow rate) that covers the entire object to be polished, and may be adjusted depending on conditions such as the size of the object to be polished. The method of supplying the polishing composition to the polishing pad is not particularly limited, and for example, a method of continuously supplying the polishing composition using a pump or the like is used. In addition, the processing time is not particularly limited as long as it is a time that can obtain the desired processing result, but it is preferable to use a shorter time due to the high polishing rate.

[0069] Yet another aspect of the present invention relates to a method for producing a polished object, comprising a step of polishing the object by the above-described polishing method. Preferred examples of the object to be polished according to this aspect are the same as those described in the description of the "object to be polished." A preferred example is a method for producing an electronic circuit board, comprising polishing an object to be polished containing resin and metal by the above-described polishing method. [Example]

[0070] The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively.

[0071] <Methods for measuring physical properties> [Average particle size of silica particles] The silica particles were measured using a particle size distribution analyzer (Microtrac particle size distribution analyzer MT3300EX II, manufactured by Microtrac-Bell Corporation) to determine the volumetric particle size distribution. In the obtained particle size distribution, the particle size at which the cumulative frequency from the small particle size side is 50% was determined as the average particle size (D 50 The average particle size of the alumina particles was also measured in the same manner as above.

[0072] [Circularity of silica particles] The silica particles were photographed using a scanning electron microscope (SEM) (Hitachi High-Tech Corporation, product name: SU8000), and the obtained SEM images were analyzed using image analysis software (Mitani Corporation, "WinROOF 2018"). Specifically, 30 silica particles were randomly selected as samples from the silica particles present in the SEM images, and the circularity of each particle (= 4πS / L 2 The circularity of the alumina particles was measured in the same manner as above.

[0073] [pH] The pH value of the polishing composition was confirmed using a pH meter (manufactured by Horiba Ltd., model number: LAQUA (registered trademark)).

[0074] [Examples 1 to 6 and Comparative Examples 1 to 5] The dry silica particles and alumina particles (abrasive grains), crystalline cellulose (redispersant), and 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) (pH adjuster) shown in Table 1 below were prepared. The silica particles or alumina particles (abrasive grains) shown in Table 1 were mixed with distilled water (dispersion medium) under stirring to a concentration of 2% by mass, and the crystalline cellulose (redispersant) was mixed to a concentration of 0.5% by mass, and then the pH was adjusted to 3.0 using HEDP (pH adjuster) to prepare a polishing composition (mixing temperature: about 25°C, mixing time: about 30 minutes). In Example 6, crystalline cellulose (redispersant) was not added.

[0075] The polishing compositions obtained above were evaluated for the polishing rate and the number of abrasive grains remaining on the surface of the object to be polished after polishing, according to the methods described below in [Polishing Rate (Polishing Speed)] and [Abrasive Grain Residue on Surface]. The results are shown in Table 1 below. In Table 1 below, the ratio of the average particle diameter of the abrasive grains to the average particle diameter of the filler (D 50 ) ratio ("abrasive grain size / filler diameter" in Table 1) is also shown.

[0076] <Evaluation> [Polishing rate (polishing speed)] As the object to be polished, a mixture of epoxy resin and filler (spherical silica, average particle size = 1.0 μm) was prepared so that the filler content was 70 mass % (object to be polished 1, specific gravity: 1.9 g / cm 3 ) In addition, a copper substrate was prepared (object to be polished 2). Subsequently, using each polishing composition, objects to be polished 1 and 2 (substrates) were simultaneously polished using the polishing apparatus and polishing conditions described below. After polishing was completed, the polishing rate (polishing rate) of the object to be polished was evaluated according to the following (polishing rate evaluation method).

[0077] (Polishing equipment and polishing conditions) Polishing device: Small desktop polishing machine (Engis Japan Co., Ltd. EJ380IN) Surface plate diameter: 380 [mm] Polishing pad: Hard polyurethane pad (Nitta DuPont IC1010) Platen rotation speed: 45 rpm Head (carrier) rotation speed: 45 rpm Polishing pressure (polishing load): 4.5 [psi] (316 [g / cm 2 〕) Flow rate of polishing composition: 100 [ml / min] Polishing time: 1 min.

[0078] (Method for evaluating polishing speed) 1. Using an analytical balance XS205 (Mettler-Toledo), the mass of the object to be polished was measured before and after polishing, and the mass change ΔM [kg] of the object to be polished before and after polishing was calculated from the difference between these values; 2. The change in mass of the object to be polished before and after polishing, ΔM (kg), is divided by the specific gravity of the object to be polished (specific gravity of the material to be polished) to obtain the change in volume of the object to be polished before and after polishing, ΔV (m 3 ] was calculated; 3. Volume change of the object to be polished before and after polishing ΔV [m 3 ] is the area of ​​the polishing surface of the object to be polished S [m 2 ] to calculate the thickness change Δd [m] of the polished object before and after polishing; 4. The thickness change Δd (m) of the workpiece before and after polishing was divided by the polishing time t (min) and then converted to μm / min. This value was taken as the polishing rate v (μm / min). Note that a higher polishing rate is preferable, but a rate of 5 μm / min or higher is acceptable, and a rate of 9.0 μm / min or higher is desirable.

[0079] [Abrasive grain residue on the surface] The copper wire surface after polishing used to evaluate the polishing rate was photographed using a scanning electron microscope (SEM) (Hitachi High-Tech Corporation, product name: SU8000), and the obtained SEM image was analyzed using image analysis software (Mitani Shoji Co., Ltd., "WinROOF 2018"). Specifically, the number of abrasive grains (silica particles or alumina particles) present within a 110 μm × 110 μm area of ​​the SEM image was counted, and this number was divided into 1 mm 2 Number of abrasive grains per mm 2) and this was taken as the number of abrasive grains remaining on the surface of the workpiece after polishing. 2 ) is preferably lower, but 1000×10 3 pieces / mm 2 Below 600×10 3 pieces / mm 2 It is desirable that it is less than 100 × 10 3 pieces / mm 2 It is particularly desirable that the number of abrasive grains remaining on the surface of the object to be polished after polishing is less than "<100" in Table 1. 2 ) is the number of abrasive grains remaining on the surface (×10 3 pieces / mm 2 )"

[0080] [Table 1]

[0081] As shown in Table 1, by using the polishing composition of the present invention, it is possible to achieve both a high polishing rate (removal speed) and a small number of abrasive grains remaining. On the other hand, when the polishing compositions of Comparative Examples 1 to 3, which used alumina particles as abrasive grains, were used, the results were inferior at least in terms of the number of abrasive grains remaining. Furthermore, when the polishing compositions of Comparative Examples 4 and 5, which contained silica particles as abrasive grains that satisfied the circularity requirement but had an average particle size outside the scope of the present invention, were used, the number of abrasive grains remaining was sufficiently low, but the polishing rate (removal speed) was significantly inferior.

[0082] The polishing composition of Example 6 and the polishing composition of Example 1 have the same composition except for the redispersant, and have the same polishing rate and number of abrasive grain residues. When the polishing compositions of Examples 1 to 5 containing the redispersant were placed in a bottle and left standing, the silica particles (abrasive grains) settled and separated into solid and liquid. However, when the bottle was turned over, the abrasive grain sediment was easily loosened and the abrasive grains dispersed in the liquid. On the other hand, even when the bottle was turned over after the silica particles (abrasive grains) settled and separated into solid and liquid when left standing in the bottle, the abrasive grain sediment did not easily loosen and the abrasive grains were difficult to redisperse in the liquid. These results demonstrate that the redispersant does not affect polishing performance such as the polishing rate (removal speed) or the number of abrasive grain residues, but it has an excellent effect on the handling of the polishing composition.

[0083] This application is based on Japanese Patent Application No. 2021-033188, filed on March 3, 2021, the disclosure of which is incorporated by reference in its entirety.

Claims

1. A polishing composition comprising an abrasive grain, a redispersant, and a dispersion medium, The abrasive grains have an average particle diameter (D ５０ ) is greater than 1.0 μm and the circularity of the primary particles is 0.90 or more, the redispersing agent contains at least one compound selected from the group consisting of crystalline cellulose, alumina sol having an average particle size of less than 1.0 μm, a condensate of phosphoric acid, an organic phosphoric acid, a phosphonic acid, and an organic phosphonic acid; Polishing composition.

2. The polishing composition described in claim 1, wherein the redispersant comprises crystalline cellulose.

3. 3. The polishing composition according to claim 1, which is used for polishing an object containing a resin and a filler.

4. The average particle diameter (D ５０ 4. The polishing composition according to claim 3, wherein the average particle size of the filler is greater than the average particle size of the filler.

5. The ratio of the average particle diameter of the silica particles to the average particle diameter of the filler (D ５０ 5. The polishing composition according to claim 4, wherein the ratio of (a) to (b) is greater than 1 and 15 or less.

6. Average particle diameter (D ５０ ) is larger than 1.0 μm and the circularity of the primary particles is 0.90 or more, and the silica particles are mixed with a re-dispersant and a dispersion medium; the redispersing agent contains at least one compound selected from the group consisting of crystalline cellulose, alumina sol having an average particle size of less than 1.0 μm, a condensate of phosphoric acid, an organic phosphoric acid, a phosphonic acid, and an organic phosphonic acid; A method for producing a polishing composition.

7. A method for producing a polishing composition as described in claim 6, wherein the redispersant contains crystalline cellulose.

8. 6. A polishing method comprising polishing an object containing a resin and a filler with the polishing composition according to claim 1.

9. The method of claim 8 , wherein the resin has a cyclic molecular structure.

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