Composition for polishing and polishing method

Abstract

To provide means capable of reducing thickness unevenness of a polishing object after polishing while polishing a resin material at high speed, in polishing of the polishing object containing a resin material.SOLUTION: The present invention relates to a composition for polishing which is used in polishing of a polishing object containing a resin material, the composition containing silica particles and water, wherein the silica particles have an average particle diameter D50 of 50 nm or more.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Planarization techniques are used to increase the flatness of various substrate surfaces. Chemical mechanical polishing (CMP) is one of the planarization techniques commonly used in the semiconductor industry. Chemical mechanical polishing is a method of planarizing the surface of an object to be polished (workpiece) such as a semiconductor substrate using a polishing composition containing abrasive grains such as silica or ceria, an anticorrosive agent, a surfactant, etc.

[0003] Furthermore, substrates containing resin materials (hereinafter referred to as "objects to be polished containing resin materials") are becoming more common. Therefore, the need for polishing compositions applicable to polishing objects to be polished containing resin materials is gradually increasing. For example, Patent Document 1 discloses a polishing composition for polishing objects to be polished containing resin materials, which contains abrasive grains, a pyrrolidone compound, and / or polyvinyl caprolactam. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2008-537704 Summary of the Invention [Problem to be solved by the invention]

[0005] The surface of a polishing object containing a resin material is generally finished to a high quality through a lapping process and a subsequent polishing process. After the lapping process, many defects exist on the surface of the polishing object. In order to reduce these defects, in the polishing process, a polishing pad is pressed against the surface of the polishing object and a polishing composition is supplied to the interface, thereby polishing the polishing object. In this case, there is a concern that local variations in the polishing effect on the polishing object may reduce the polishing efficiency or cause uneven thickness of the polished object (also referred to as the "polished object").

[0006] Therefore, for polishing objects containing resin materials, there is a need for a polishing composition that can efficiently polish the resin material while reducing thickness unevenness of the polished object after polishing. However, at present, no satisfactory polishing composition has been obtained.

[0007] Therefore, an object of the present invention is to provide a means for polishing an object containing a resin material, which can polish the resin material at high speed while reducing unevenness in the thickness of the object after polishing. [Means for solving the problem]

[0008] 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 the following means, thereby completing the present invention.

[0009] That is, the above-mentioned object of the present invention is to provide a polishing composition used for polishing an object to be polished that contains a resin material, the polishing composition containing silica particles and water, wherein the silica particles have an average particle diameter D 50 The aforementioned problems can be solved by a polishing composition having a particle size of 50 nm or more. [Effects of the Invention]

[0010] According to the present invention, there is provided a means for polishing a resin material at high speed while reducing unevenness in the thickness of the polished object after polishing. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes embodiments of the present invention. The embodiments shown here are provided as examples to embody the technical concept of the present invention and are not intended to limit the present invention. Therefore, all other possible embodiments, methods of use, and operational techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included in the scope and spirit of the present invention, as well as in the scope of the inventions described in the claims and their equivalents. The embodiments described in this specification can be combined in any manner to create other embodiments.

[0012] In this specification, "X to Y" means "X or more and Y or less," with the preceding and following numerical values ​​(X and Y) being included as upper and lower limits. When multiple "X to Y" are used, for example, "X1 to Y1 or X2 to Y2," the disclosure of each numerical value as an upper limit, the disclosure of each numerical value as a lower limit, and combinations of the upper and lower limits are all disclosed (i.e., they constitute legitimate grounds for amendment). Specifically, amendments to X1 or more, amendments to Y2 or less, amendments to X1 or less, amendments to Y2 or more, amendments between X1 and X2, and amendments between X1 and Y2 must all be deemed legitimate. Unless otherwise specified, in this specification, operations and measurements of physical properties, etc. are performed at room temperature (20°C to 25°C) and a relative humidity of 40% RH to 50% RH. Additionally, where features or aspects of the present disclosure are described in terms of a Markush group, those skilled in the art will recognize that the present disclosure is thereby described in terms of any individual component or subgroup of components of the Markush group. Also, all combinations of embodiments and descriptions disclosed herein should be understood to be disclosed in this application, i.e., should be understood to be grounds for amendment.

[0013] A first aspect of the present invention is a polishing composition used for polishing an object to be polished, which includes a resin material, and contains silica particles and water, and the silica particles have an average particle diameter D 50 The polishing composition has a particle size of 50 nm or more.

[0014] A second aspect of the present invention is a polishing composition used for polishing an object to be polished, including a resin material, comprising silica particles, a polishing accelerator, and water, wherein the polishing accelerator is at least one selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound, and wherein the particle diameter of the silica particles at which the cumulative frequency from the small particle diameter side in a volume-based particle size distribution is 50% is defined as D. 50 The BET specific surface area is SA, and the D 50 When SA' is the theoretical specific surface area calculated from the above formula, the irregularity N expressed as N=SA / SA' is 1.5 or more.

[0015] The polishing compositions according to the first and second embodiments having the above-described configuration polish resin materials at high speed while reducing unevenness in thickness of the object to be polished after polishing.

[0016] A third aspect of the present invention includes polishing an object to be polished by supplying a polishing composition between an object to be polished containing a resin material and a polishing pad, wherein the polishing composition contains silica particles and water, and the silica particles have an average particle diameter D 50 This is a polishing method in which the surface roughness is 50 nm or more.

[0017] A fourth aspect of the present invention comprises polishing an object to be polished, which comprises supplying a polishing composition between an object to be polished containing a resin material and a polishing pad, the polishing composition comprising silica particles, a polishing accelerator, and water, the polishing accelerator being at least one selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound, and the silica particles are selected from the group consisting of a particle diameter at which the cumulative frequency from the small particle diameter side in a volume-based particle size distribution is 50% and a particle diameter at which the cumulative frequency from the small particle diameter side in a volume-based particle size distribution is 50%. 50 The BET specific surface area is SA, and the D 50 When SA' is the theoretical specific surface area calculated from the above formula, the irregularity N expressed as N=SA / SA' is 1.5 or more.

[0018] A fifth aspect of the present invention is a polishing system including an object to be polished containing a resin material, a polishing pad, and a polishing composition, wherein the polishing composition contains silica particles and water; and the silica particles have an average particle diameter D 50 is 50 nm or more; and the surface of the object to be polished is brought into contact with the polishing pad and the polishing composition.

[0019] A sixth aspect of the present invention is a polishing system including an object to be polished containing a resin material, a polishing pad, and a polishing composition, wherein the polishing composition contains silica particles, a polishing accelerator, and water; the polishing accelerator is at least one selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound; and the silica particles have a particle size D at which a cumulative frequency from the small particle size side in a volume-based particle size distribution of the silica particles is 50%. 50 The BET specific surface area is SA, and the D 50 where SA' is the theoretical specific surface area calculated from the above formula, the irregularity N, expressed as N=SA / SA', is 1.5 or more; and the surface of the object to be polished is brought into contact with the polishing pad and the polishing composition.

[0020] According to the polishing method and / or polishing system having the configurations of the third to sixth embodiments, it is possible to polish a resin material at high speed while reducing unevenness in the thickness of the polished object after polishing.

[0021] The present invention will be described in detail below. In this specification, the description of "the polishing composition according to this embodiment" is common to the first to sixth embodiments. In addition, in this specification, the term "polishing removal rate" is synonymous with the terms "polishing rate" and "polishing rate."

[0022] [Polished object] The polishing composition according to the present invention is particularly suitable for polishing substrates made of resin materials, and the technical effects of the present invention are fully exhibited when polishing such substrates.

[0023] The resin material contained in the object to be polished is not particularly limited, but examples thereof include poly(meth)acrylates ((meth)acrylic resins) such as polymethyl methacrylate (PMMA) and polycyclohexyl methacrylate (PCHMA); polyethylene terephthalate (PET); polycarbonate (PC); polyvinyl chloride (PVC); polystyrene (PS); thiourethane resins; polysulfides; episulfide resins; polyolefins such as polyethylene (PE), ultra-high molecular weight polyethylene (UHMWPE), and polypropylene (PP); polyureaurethane; poly(meth)(thio)acrylates; allyl diglycidyl carbonate; polybenzoxazole (PBO); Examples include polybutylene terephthalate (PBT); polyimide (PI); polyamide (PA); epoxy resin; urethane acrylate resin; polyester resin; unsaturated polyester resin; phenolic resin; polynorbornene resin; polyacetal (POM); modified polyphenylene ether (m-PPE); syndiotactic polystyrene (SPS); amorphous polyarylate (PAR); polysulfone (PSF); polyethersulfone (PES); polyphenylene sulfide (PPS); polyetheretherketone (PEEK); polyetherimide (PEI); benzocyclobutene (BCB); fluororesin; and liquid crystal polymer (LCP).

[0024] In the polishing composition according to this embodiment, the resin material contained in the object to be polished is preferably an optical resin. That is, according to one embodiment, in the polishing composition according to this embodiment, the resin material is an optical resin material. The optical resin is a light-transmitting resin, and is used as a material for constituting optical components such as films, plates (e.g., optical waveguides, diffusion plates, light guide plates (waveguides), and polarizing plates for surface light source devices such as liquid crystal screens, light-emitting displays, light-emitting signs, signs, and lighting) and lenses (e.g., films, substrates, and prism sheets used in liquid crystal display devices; lenses in signal reading lens systems of optical disc devices; Fresnel lenses for projection screens; lenticular lenses, etc.) used in various optical-related devices.

[0025] Examples of such optical resins (light-transmitting resins) include poly(meth)acrylates ((meth)acrylic resins) such as polymethyl methacrylate (PMMA) and polycyclohexyl methacrylate (PCHMA); polyethylene terephthalate (PET); polycarbonate (PC); polyvinyl chloride (PVC); polystyrene (PS); thiourethane resins; polysulfides; episulfide resins; polyolefins such as polyethylene (PE), ultra-high molecular weight polyethylene (UHMWPE), and polypropylene (PP); polyureaurethane; poly(meth)(thio)acrylates; allyl diglycidyl carbonate; polyimide (PI); polyamide (PA); polyester resins; and derivatives thereof. Therefore, the polishing composition according to this embodiment is preferably used for polishing an object containing one or more selected from the group consisting of poly(meth)acrylate (preferably polymethyl methacrylate (PMMA), polycyclohexyl methacrylate (PCHMA), etc.), polyethylene terephthalate (PET), polycarbonate (PC), polyvinyl chloride (PVC), polystyrene (PS), thiourethane resin, polysulfide, episulfide resin, polyolefin (preferably polyethylene (PE), ultra-high molecular weight polyethylene (UHMWPE), polypropylene (PP), etc.), polyureaurethane, poly(meth)(thio)acrylate, allyl diglycidyl carbonate, polyimide (PI), polyamide (PA), polyester resin, and derivatives thereof. This allows for efficient polishing of resin materials at high speed while reducing thickness unevenness of the polished object after polishing.

[0026] The resin material contained in the object to be polished preferably contains one or more selected from the group consisting of thiourethane resin, episulfide resin, polycarbonate, polymethyl methacrylate, and polypropylene. The above resin materials can be used alone or in combination of two or more. By containing the above resin material in the object to be polished, it is possible to efficiently polish the resin material at high speed while reducing unevenness in the thickness of the object to be polished after polishing.

[0027] The polishing composition of this embodiment can efficiently reduce thickness unevenness of the polished object after polishing by polishing a thin object to be polished at high speed while polishing the resin material. That is, the thickness of the object to be polished (the object to be polished before polishing) is preferably 3.0 mm or less, more preferably 2.0 mm or less, even more preferably 1.0 mm or less, particularly preferably 0.8 mm or less, and most preferably 0.6 mm or less. According to one embodiment, the object to be polished before polishing with the polishing composition of this embodiment has an average thickness of 1 mm or less. When polishing with the polishing composition of this embodiment, the change in thickness of the object to be polished before and after polishing can be about 0.1 mm. Therefore, the thickness of the object to be polished (the object to be polished after polishing) is preferably 3.0 mm or less, more preferably 2.0 mm or less, even more preferably 1.0 mm or less, even more preferably 0.9 mm or less, particularly preferably 0.8 mm or less, and most preferably 0.6 mm or less. According to one embodiment, the polishing composition of this embodiment polishes an object to be polished to an average thickness of 1 mm or less. In this specification, the average thickness of the object to be polished can be measured with a micrometer or the like.

[0028] In the polishing composition of this embodiment, the object to be polished (the object to be polished before polishing) is preferably flat. In this specification, flat means that the GBIR (Global Backside Ideal Range) measured in the Examples described later is less than 2.0 μm. The GBIR of the object to be polished (the object to be polished before polishing) is more preferably 1.5 μm or less, even more preferably 1.2 μm, particularly preferably 1.0 μm or less, and most preferably 0.8 μm or less. The lower limit of GBIR is 0 μm. The GBIR is measured by adsorbing the entire backside of the object to be polished onto a flat chuck surface, using the backside as a reference surface, and measuring the height of the entire wafer from the reference surface, and expressing the distance from the highest to lowest height. The GBIR is a value obtained by the measurement method described in the Examples described later.

[0029] Therefore, the polishing composition according to this embodiment is suitable for polishing a polishing object (an object to be polished before polishing) that is flat (i.e., GBIR less than 2.0 μm) and has a thickness of 1.5 mm or less (preferably 1 mm or less, more preferably 1.0 mm or less, even more preferably 0.8 mm or less, particularly preferably 0.7 mm or less, and most preferably 0.6 mm or less). This allows for efficient polishing of resin materials at high speed while reducing unevenness in the thickness of the polished object after polishing.

[0030] [Polishing composition] In the present invention, the polishing composition includes a first embodiment and a second embodiment. Below, the constitution of the main components contained in the polishing composition according to the first embodiment and the constitution of the main components contained in the polishing composition according to the second embodiment will be described in order.

[0031] <Polishing composition according to the first embodiment> The polishing composition according to the first embodiment is a polishing composition used for polishing an object to be polished that contains a resin material, and contains silica particles and water, and the silica particles have an average particle diameter D 50 The polishing composition has a particle size of 50 nm or more.

[0032] [Silica particles] The polishing composition according to the first embodiment contains silica particles as abrasive grains. The abrasive grains mechanically polish the object to be polished, improving the polishing removal rate. The silica particles have an appropriate hardness to reduce defects in the resin material.

[0033] <Secondary particle diameter D 50 > In the polishing composition according to the first embodiment, the D of the silica particles 50 (The particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 50% (the secondary particle diameter at which the cumulative frequency from the small particle diameter side is 50%)) is 50 nm or more (0.05 μm or more). 50 If the thickness is less than 50 nm, the polishing removal rate of the resin material (object to be polished) decreases.

[0034] When polishing a resin-containing object, the object is first polished using a lapping process to adjust the thickness. However, this process leaves many defects on the surface of the object. To reduce these defects, the surface of the object is polished using a polishing composition during the polishing process. However, there is concern that local variations in the polishing effect on the object may cause thickness unevenness during polishing. For example, as polishing time passes, the supplied polishing composition may accumulate at the outer edge of the object, further increasing the local variations in the polishing effect. In other words, the longer it takes to reduce defects during the polishing process, the greater the thickness unevenness tends to become. Therefore, a higher polishing speed is required for objects to be polished that contain resin materials. The present inventors have discovered that using abrasive grains with a specific particle size or larger can achieve a significantly higher polishing speed and reduce thickness unevenness of the object after polishing. In other words, the polishing composition of the first embodiment can polish at a significantly high polishing rate, while reducing the local variation in the polishing effect that may occur during polishing, and can maintain or improve the flatness of the object to be polished.In addition, it has also been found that the polishing composition of the first embodiment has low surface roughness (Rms) and few scratches on the surface of the object to be polished after polishing.That is, the polishing composition of the first embodiment can reduce defects on the surface of the object to be polished, and can also improve the surface quality of the object to be polished after polishing.

[0035] As mentioned above, the D 50 When the D of the silica particles is 50 nm or more (0.05 μm or more), the polishing removal rate of the resin material can be improved and the thickness unevenness of the polished object can be more efficiently reduced after polishing. 50 is preferably greater than 0.05 μm (greater than 50 nm), more preferably 0.06 μm or more, even more preferably 0.08 μm or more, particularly preferably 0.1 μm or more, and most preferably 0.15 μm or more. 50Preferably, the diameter of the silica particles is 1 μm or less, may be 0.8 μm or less, more preferably 0.5 μm or less, even more preferably 0.3 μm or less, particularly preferably 0.25 μm or less, and most preferably 0.2 μm or less. According to one embodiment, the silica particles have a diameter of D 50 is 50 nm or more and less than 200 nm.

[0036] Silica particle D 10 is the particle size at which the cumulative frequency from the small particle size side is 10% in the volume-based particle size distribution (secondary particle size at which the cumulative frequency from the small particle size side is 10%). 10 is D 50 The diameter of the silica particles is not particularly limited as long as it is 50 nm or more, but is preferably 0.005 μm or more, more preferably 0.01 μm or more, even more preferably 0.02 μm or more, particularly preferably 0.05 μm or more, and most preferably 0.07 μm or more. 10 The D of the silica particles is preferably 0.5 μm or less, may be 0.3 μm or less, more preferably 0.25 μm or less, even more preferably 0.2 μm or less, particularly preferably 0.15 μm or less, and most preferably 0.13 μm or less. 10 When the polishing rate is within the above range, it is possible to more efficiently improve the polishing removal rate of the resin material and reduce unevenness in the thickness of the object to be polished after polishing.

[0037] Silica particle D 90 is the particle size at which the cumulative frequency from the small particle size side is 90% in the volume-based particle size distribution (the secondary particle size at which the cumulative frequency from the small particle size side is 90%). 90 is D 50 The diameter of the silica particles is not particularly limited as long as it is 50 nm or more, but is preferably 0.1 μm or more, more preferably 0.12 μm or more, even more preferably 0.15 μm or more, particularly preferably 0.2 μm or more, and most preferably 0.3 μm or more. 90The D of the silica particles is preferably 1.5 μm or less, may be 1.2 μm or less, more preferably 1.0 μm or less, even more preferably 0.8 μm or less, particularly preferably 0.7 μm or less, and most preferably 0.5 μm or less. 90 When the polishing rate is within the above range, it is possible to more efficiently improve the polishing removal rate of the resin material and reduce unevenness in the thickness of the object to be polished after polishing.

[0038] Silica particle D 10 D against 90 The ratio of (hereinafter referred to as "D 90 / D 10 ") is preferably 1.2 or more, more preferably 1.5 or more, even more preferably 1.8 or more, particularly preferably 2.0 or more, and most preferably 2.5 or more. In addition, the D 90 / D 10 is preferably 6.5 or less, more preferably 6.0 or less, even more preferably 5.0 or less, particularly preferably 4.0 or less, and most preferably 3.5 or less. 90 / D 10 When the polishing rate is within the above range, it is possible to more efficiently improve the polishing removal rate of the resin material and reduce unevenness in the thickness of the object to be polished after polishing.

[0039] According to one embodiment, the polishing composition of the first type has a particle size where the cumulative frequency from the small particle size side in the volume-based particle size distribution of silica particles is 10%. 10 The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution of silica particles is 90% is defined as D 90 When the D of silica particles 10 D against 90 The ratio (D 90 / D 10 ) is 2.0 or greater.

[0040] Silica particle D 10 , D 50 , and D 90can be determined by dynamic light scattering, laser diffraction, laser scattering, or pore electrical resistance, etc. In this specification, the values ​​used are those determined from the particle diameters at which the cumulative frequency from the small particle diameter side is 10%, 50%, and 90% in the volume-based particle size distribution measured using a laser diffraction particle size distribution analyzer. More specifically, it can be measured by the method described in the Examples.

[0041] <Deformity degree N> The silica particles contained in the polishing composition according to the first embodiment have a particle size D where the cumulative frequency from the small particle size side in the volume-based particle size distribution is 50%. 50 The BET specific surface area is SA, and D 50 When SA' is the theoretical specific surface area calculated from the above, the irregularity N, expressed as N = SA / SA', is preferably 1.2 or more. The irregularity N is a parameter that indicates the degree of irregularity of the particle shape relative to a perfect sphere of the same particle diameter, and the larger the irregularity N is above 1, the greater the degree of irregularity of the particle shape. An irregularity N of 1 indicates that the particle is a perfect sphere. The silica particles according to the first embodiment have an irregularity N of preferably 1.2 or more (more preferably 1.5 or more), and therefore have a large degree of irregularity of the particle shape.

[0042] After extensive research into reducing thickness unevenness while reducing surface defects of the object to be polished during the lapping process when polishing an object containing a resin material, the inventors discovered that irregularities in the shape of the abrasive grains can significantly increase the polishing rate and reduce thickness unevenness of the object to be polished after polishing. If the irregularity N of the silica particles is 1.2 or higher, defects on the surface of the object to be polished can be reduced, and the surface quality of the object to be polished after polishing can also be improved. The upper limit of the irregularity N of the silica particles is not particularly limited, but in practice it is 3.0 or less. The irregularity N of the silica particles is preferably 1.6 or more, more preferably 1.7 or more, even more preferably 1.8 or more, and particularly preferably 1.9 or more.

[0043] The BET specific surface area SA of the silica particles and the theoretical specific surface area SA' of the silica particles used in calculating the irregularity N can be calculated in the same manner as described below in the polishing composition of the second embodiment.

[0044] The shape of the silica particles is not particularly limited. Examples of the shape of the silica particles include polygonal prisms such as triangular prisms and quadrangular prisms, cylinders, bale-shaped cylinders in which the center is bulged more than the ends, donut-shaped discs with a central hole, plates, cocoon-shaped discs with a central constriction, associative spheres in which a plurality of particles are integrated, confetti-shaped discs with a plurality of protrusions on the surface, rugby ball-shaped discs, truncated cones, pyramidal discs, truncated pyramidal discs, hemispheres, needles, and irregular shapes.

[0045] The concentration (content) of silica particles in the polishing composition is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, even more preferably 2% by mass or more, particularly preferably 5% by mass or more, and most preferably 10% by mass or more, based on the total mass of the polishing composition. As the concentration of silica particles increases, the polishing removal rate is further improved and thickness unevenness of the polished object can be reduced after polishing. Furthermore, the concentration (content) of silica particles is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less, even more preferably 30% by mass or less, particularly preferably 25% by mass or less, and most preferably 20% by mass or less, based on the total mass of the polishing composition. Within the above range, the polishing removal rate of the resin material can be further improved and thickness unevenness of the polished object can be reduced after polishing. A preferred example of the concentration (content) of silica particles is preferably 0.1% by mass or more and 50% by mass or less, more preferably 0.5% by mass or more and 40% by mass or less, even more preferably 1% by mass or more and 35% by mass or less, even more preferably 2% by mass or more and 30% by mass or less, particularly preferably 5% by mass or more and 25% by mass or less, and most preferably 10% by mass or more and 20% by mass or less, based on the total mass of the polishing composition.Silica particles can be used alone or in combination of two or more types.When two or more types of silica particles are used, the concentration (content) of the silica particles is the total amount.

[0046] The silica particles are preferably colloidal silica. Methods for producing colloidal silica include the sodium silicate method and the sol-gel method, and colloidal silica produced by either method can be suitably used. The D of silica particles (preferably colloidal silica) 50 To make the D of the silica particles 50 nm or more, it is possible to appropriately control the conditions during the production (for example, reaction temperature, reaction concentration, etc.). Commercially available silica particles may be used. In this case, the D of the silica particles 50By measuring the above, silica particles to be used in the polishing composition of the first embodiment can be selected.

[0047] In addition, the D of silica particles 10 , D 90 The degree of irregularity N can also be appropriately controlled by selecting the conditions for producing the silica particles.

[0048] [Polishing accelerator] The polishing composition of the first type preferably contains a polishing accelerator. The polishing accelerator is one or more selected from the group consisting of aluminum salts of monovalent acids, pyrrolidone compounds, and caprolactam compounds. The polishing accelerator has the effect of assisting polishing with abrasive grains. According to one embodiment, the polishing composition of the first type further contains a polishing accelerator, and the polishing accelerator is one or more selected from the group consisting of aluminum salts of monovalent acids, pyrrolidone compounds, and caprolactam compounds.

[0049] Examples of aluminum salts of monovalent acids include aluminum salts of monovalent inorganic acids or monovalent organic acids. Specific examples of monovalent inorganic acids include nitric acid, hydrochloric acid, perchloric acid, nitrous acid, hypochlorous acid, hypophosphorous acid (phosphinic acid; HPO(OH)), and sulfamic acid. Specific examples of monovalent organic acids include lactic acid, nicotinic acid, acetic acid, formic acid, propionic acid, valeric acid, caproic acid, caprylic acid, capric acid, cyclohexanecarboxylic acid, phenylacetic acid, benzoic acid, crotonic acid, methacrylic acid, methanesulfonic acid, ethanesulfonic acid, aminoethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, 1-naphthalenesulfonic acid, and 2-naphthalenesulfonic acid. When the aluminum salt of a monovalent acid contains water of hydration, the content of these acids excludes the water of hydration. Preferred examples of aluminum salts of monovalent acids include aluminum nitrate and aluminum chloride.

[0050] The concentration (content) of the aluminum salt of a monovalent acid in the polishing composition is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, particularly preferably 2% by mass or more, particularly preferably 3% by mass or more, and most preferably 5% by mass or more, relative to the total mass of the polishing composition. As the concentration of the aluminum salt of a monovalent acid increases, the polishing removal rate improves and thickness unevenness of the polished object can be reduced after polishing. Furthermore, the concentration (content) of the aluminum salt of a monovalent acid is preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 18% by mass or less, even more preferably 15% by mass or less, particularly preferably 12% by mass or less, and most preferably 10% by mass or less, relative to the total mass of the polishing composition. Within the above range, the polishing removal rate of the resin material can be further improved and thickness unevenness of the polished object can be reduced. A preferred example of the concentration (content) of the aluminum salt of a monovalent acid is preferably 0.1% by mass or more and 25% by mass or less, more preferably 0.5% by mass or more and 20% by mass or less, even more preferably 1% by mass or more and 18% by mass or less, even more preferably 2% by mass or more and 15% by mass or less, particularly preferably 3% by mass or more and 12% by mass or less, and most preferably 5% by mass or more and 10% by mass or less, based on the total mass of the polishing composition. The aluminum salt of a monovalent acid can be used alone or in combination of two or more. When two or more types of aluminum salts of a monovalent acid are used, the concentration (content) of the aluminum salt of a monovalent acid is the total amount.

[0051] Examples of pyrrolidone compounds include 2-pyrrolidone or 2-pyrrolidone derivatives, and polymers having structural units derived from 2-pyrrolidone derivatives. Examples of 2-pyrrolidone derivatives include 2-pyrrolidone, N-octyl-2-pyrrolidone, N-dodecyl-2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, N-butyl-2-pyrrolidone, N-hexyl-2-pyrrolidone, N-decyl-2-pyrrolidone, N-octadecyl-2-pyrrolidone, N-hexadecyl-2-pyrrolidone, and N-vinyl-2-pyrrolidone. Examples of polymers having structural units derived from 2-pyrrolidone derivatives include homopolymers (hereinafter also referred to as "polyvinylpyrrolidone" or "PVP") and copolymers of N-vinyl-2-pyrrolidone. These pyrrolidone compounds may be used alone or in combination of two or more. Among these, polyvinylpyrrolidone is preferred as the pyrrolidone compound.

[0052] The concentration (content) of the pyrrolidone compound in the polishing composition is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.003% by mass or more, even more preferably 0.005% by mass or more, particularly preferably 0.007% by mass or more, particularly preferably 0.008% by mass or more, and most preferably 0.01% by mass or more, relative to the total mass of the polishing composition. As the concentration of the pyrrolidone compound increases, the polishing removal rate is further improved and thickness unevenness of the polished object can be reduced after polishing. Furthermore, the concentration (content) of the pyrrolidone compound is preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1.5% by mass or less, even more preferably 1.2% by mass or less, particularly preferably 1% by mass or less, and most preferably 0.5% by mass or less, relative to the total mass of the polishing composition. Within the above range, the polishing removal rate of the resin material can be further improved and thickness unevenness of the polished object can be reduced after polishing. A preferred example of the concentration (content) of the pyrrolidone compound is, relative to the total mass of the polishing composition, preferably 0.001% by mass or more and 3% by mass or less, more preferably 0.003% by mass or more and 2% by mass or less, even more preferably 0.005% by mass or more and 1.5% by mass or less, particularly preferably 0.007% by mass or more and 1.2% by mass or less, particularly preferably 0.008% by mass or more and 1% by mass or less, and most preferably 0.01% by mass or more and 0.5% by mass or less. When two or more pyrrolidone compounds are used, the concentration (content) of the pyrrolidone compounds is the total amount.

[0053] In one embodiment of the polishing composition of the first type, the pyrrolidone compound is polyvinylpyrrolidone. In this case, the weight-average molecular weight (Mw) of polyvinylpyrrolidone is preferably 2,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, and particularly preferably 7,500 or more. Furthermore, the weight-average molecular weight (Mw) of polyvinylpyrrolidone is preferably 900,000 or less, more preferably 500,000 or less, even more preferably 250,000 or less, particularly preferably 100,000 or less, and most preferably 55,000 or less. Polyvinylpyrrolidone with a weight-average molecular weight within the above range can more efficiently improve the polishing removal rate of resin materials and reduce thickness unevenness of the polished object after polishing.

[0054] Examples of the caprolactam compound include ε-caprolactam or its derivatives, and polymers having structural units derived from ε-caprolactam or its derivatives. Caprolactam compounds can be used as a substitute for pyrrolidone compounds. Examples of the caprolactam compound include ε-caprolactam, nylon 6, etc.

[0055] The concentration (content) of the caprolactam compound in the polishing composition is not particularly limited, but is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, and even more preferably 0.1 mass% or more, based on the total mass of the polishing composition.Furthermore, the concentration (content) of the caprolactam compound is preferably 5 mass% or less, more preferably 2 mass% or less, and even more preferably 1 mass% or less.If the content of the caprolactam compound is within the above range, it can more efficiently improve the polishing removal rate of the resin material and reduce the thickness unevenness of the polished object after polishing.

[0056] The pyrrolidone compound and the caprolactam compound may be commercially available products or may be synthesized by a known method.

[0057] According to one embodiment, in the polishing composition of the first embodiment, the polishing accelerator contains an aluminum salt of a monovalent acid and a pyrrolidone compound. By containing an aluminum salt of a monovalent acid and a pyrrolidone compound as a polishing accelerator, the polishing removal rate of the resin material can be improved and thickness unevenness of the polished object can be more efficiently reduced after polishing.

[0058] [water] The polishing composition according to the first embodiment contains water. The water disperses or dissolves each component. From the viewpoint of preventing impurities from affecting other components of the polishing composition, it is preferable to use water of as high purity as possible. Specifically, pure water or ultrapure water, which has been filtered to remove impurity ions using an ion exchange resin, or distilled water, is preferred. Furthermore, the polishing composition may further contain an organic solvent as a dispersion medium in order to control the dispersibility of other components in the polishing composition.

[0059] <Polishing composition according to the second embodiment> The polishing composition according to the second embodiment is a polishing composition used for polishing an object to be polished, which includes a resin material, and contains silica particles, a polishing accelerator, and water. The polishing accelerator is at least one selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound. The particle diameter of the silica particles at which the cumulative frequency from the small particle diameter side in a volume-based particle size distribution is 50% is defined as D. 50 The BET specific surface area is SA, and the D 50 When SA' is the theoretical specific surface area calculated from the above formula, the irregularity N expressed as N=SA / SA' is 1.5 or more.

[0060] [Silica particles] The polishing composition according to the second embodiment contains silica particles as abrasive grains. The abrasive grains mechanically polish the object to be polished, improving the polishing removal rate. The silica particles have an appropriate hardness to reduce defects in the resin material.

[0061] <Deformity degree N> The silica particles contained in the polishing composition according to the second embodiment have a particle size D where the cumulative frequency from the small particle size side in the volume-based particle size distribution is 50%. 50 The BET specific surface area is SA, and D 50 When SA' is the theoretical specific surface area calculated from the above, the irregularity N, expressed as N = SA / SA', is 1.5 or more. The irregularity N is a parameter that indicates the degree of irregularity of the particle shape relative to a perfect sphere of the same particle diameter, and the larger the irregularity N is above 1, the greater the degree of irregularity of the particle shape. An irregularity N of 1 indicates that the particle is a perfect sphere. The silica particles according to the second embodiment have an irregularity N of 1.5 or more, and therefore have a large degree of irregularity of the particle shape.

[0062] When polishing a resin-containing object, the object is first polished using a lapping process to adjust the thickness. However, this process leaves many defects on the surface of the object. To reduce these defects, the surface of the object is polished using a polishing composition during the polishing process. However, there are concerns that local variations in the polishing effect on the object may lead to uneven thickness due to polishing. For example, as the polishing time progresses, the supplied polishing composition may accumulate at the outer edge of the object, further increasing the local variations in the polishing effect. In other words, the longer it takes to reduce defects during the polishing process, the greater the uneven thickness tends to be. Therefore, even higher polishing rates are required for objects containing resin-containing materials. It is generally known that relatively large abrasive grains have a high polishing removal rate, and that the polishing removal rate increases as the irregularity and aspect ratio of the abrasive grains increase. The inventors have found that the irregular shape of these abrasive grains, in the presence of a specific polishing accelerator, can bring about a significantly high polishing rate and reduce uneven thickness of the polished object after polishing. In other words, the polishing composition of the second embodiment can polish at a significantly high polishing rate, while reducing local variations in the polishing effect that may occur during polishing, and can maintain or improve the flatness of the polished object. It has also been found that the polishing composition of the second embodiment reduces scratches on the surface of the polished object after polishing. In other words, the polishing composition of the second embodiment can reduce defects on the surface of the polished object and improve the surface quality of the polished object after polishing.

[0063] If the irregularity N of the silica particles is less than 1.5, the polishing removal rate of the resin material (object to be polished) decreases. The upper limit of the irregularity N of the silica particles is not particularly limited, but in practice it is 3.0 or less. The irregularity N of the silica particles is preferably 1.6 or more, more preferably 1.7 or more, even more preferably 1.8 or more, and particularly preferably 1.9 or more.

[0064] The BET specific surface area SA of the silica particles used in calculating the degree of irregularity N is the specific surface area measured in accordance with JIS Z8830: 2013. More specifically, it can be measured by the method described in the examples.

[0065] The theoretical specific surface area SA' of silica particles is defined as D, which is the particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution is 50%. 50 The value was calculated using the following formula (1).

[0066]

number

[0067] In the above formula (1), ρ is the density of the silica particles, and is 1.80 to 2.20 g / cm 3 The density of the silica particles can be calculated, for example, by the method described in WO 2018 / 012176 (true density of silica).

[0068] Here, the D of silica particles 50 is the particle diameter at which the cumulative frequency from the small particle diameter side is 50% in the volume-based particle size distribution (secondary particle diameter at which the cumulative frequency from the small particle diameter side is 50%). 50 is not particularly limited as long as the degree of irregularity N is 1.5 or more, but is preferably 0.05 μm or more, more preferably 0.06 μm or more, even more preferably 0.08 μm or more, particularly preferably 0.1 μm or more, and most preferably 0.15 μm or more. 50 Preferably, the diameter of the silica particles is 1 μm or less, may be 0.8 μm or less, more preferably 0.5 μm or less, even more preferably 0.3 μm or less, particularly preferably 0.25 μm or less, and most preferably 0.2 μm or less. According to one embodiment, the silica particles have a diameter of D 50 The diameter of silica particles is 50 nm or more and less than 200 nm. 50When the polishing rate is within the above range, it is possible to more efficiently improve the polishing removal rate of the resin material and reduce unevenness in the thickness of the object to be polished after polishing.

[0069] Silica particle D 10 is the particle size at which the cumulative frequency from the small particle size side is 10% in the volume-based particle size distribution (secondary particle size at which the cumulative frequency from the small particle size side is 10%). 10 is not particularly limited as long as the degree of irregularity N is 1.5 or more, but is preferably 0.005 μm or more, more preferably 0.01 μm or more, even more preferably 0.02 μm or more, particularly preferably 0.05 μm or more, and most preferably 0.07 μm or more. 10 The D of the silica particles is preferably 0.5 μm or less, may be 0.3 μm or less, more preferably 0.25 μm or less, even more preferably 0.2 μm or less, particularly preferably 0.15 μm or less, and most preferably 0.13 μm or less. 10 When the polishing rate is within the above range, it is possible to more efficiently improve the polishing removal rate of the resin material and reduce unevenness in the thickness of the object to be polished after polishing.

[0070] Silica particle D 90 is the particle size at which the cumulative frequency from the small particle size side is 90% in the volume-based particle size distribution (the secondary particle size at which the cumulative frequency from the small particle size side is 90%). 90 is not particularly limited as long as the degree of irregularity N is 1.5 or more, but is preferably 0.07 μm or more, more preferably 0.1 μm or more, even more preferably 0.12 μm or more, particularly preferably 0.15 μm or more, and most preferably 0.2 μm or more. 90 The D of the silica particles is preferably 1.5 μm or less, may be 1.2 μm or less, more preferably 1.0 μm or less, even more preferably 0.8 μm or less, particularly preferably 0.7 μm or less, and most preferably 0.5 μm or less.90 When the polishing rate is within the above range, it is possible to more efficiently improve the polishing removal rate of the resin material and reduce unevenness in the thickness of the object to be polished after polishing.

[0071] Silica particle D 10 D against 90 The ratio of (hereinafter referred to as "D 90 / D 10 ") is preferably 1.2 or more, more preferably 1.5 or more, even more preferably 1.8 or more, particularly preferably 2.0 or more, and most preferably 2.5 or more. In addition, the D 90 / D 10 is preferably 6.5 or less, more preferably 6.0 or less, even more preferably 5.0 or less, particularly preferably 4.0 or less, and most preferably 3.5 or less. 90 / D 10 When the polishing rate is within the above range, it is possible to more efficiently improve the polishing removal rate of the resin material and reduce unevenness in the thickness of the object to be polished after polishing.

[0072] According to one embodiment, the polishing composition of the second type has a particle size where the cumulative frequency from the small particle size side in the volume-based particle size distribution of silica particles is 10%. 10 The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution of silica particles is 90% is defined as D 90 When the D of silica particles 10 D against 90 The ratio (D 90 / D 10 ) is 2.0 or greater.

[0073] Silica particle D 10 , D 50 , and D 90can be determined by dynamic light scattering, laser diffraction, laser scattering, or pore electrical resistance, etc. In this specification, the values ​​used are those determined from the particle diameters at which the cumulative frequency from the small particle diameter side is 10%, 50%, and 90% in the volume-based particle size distribution measured using a laser diffraction particle size distribution analyzer. More specifically, it can be measured by the method described in the Examples.

[0074] The shape of the silica particles is not particularly limited as long as the irregularity N is 1.5 or more. Examples of the shape of the silica particles include polygonal prisms such as triangular prisms and quadrangular prisms, cylinders, bale-shaped cylinders in which the center is bulging more than the ends, donut-shaped disks with a central hole, plates, cocoon-shaped disks with a central constriction, associative spheres in which multiple particles are integrated, confetti-shaped disks with multiple protrusions on the surface, rugby ball-shaped disks, truncated cones, pyramidal disks, hemispheres, needles, and irregular shapes.

[0075] The concentration (content) of silica particles in the polishing composition is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, even more preferably 2% by mass or more, particularly preferably 5% by mass or more, and most preferably 10% by mass or more, based on the total mass of the polishing composition. As the concentration of silica particles increases, the polishing removal rate is further improved and thickness unevenness of the polished object can be reduced after polishing. Furthermore, the concentration (content) of silica particles is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less, even more preferably 30% by mass or less, particularly preferably 25% by mass or less, and most preferably 20% by mass or less, based on the total mass of the polishing composition. Within the above range, the polishing removal rate of the resin material can be further improved and thickness unevenness of the polished object can be reduced after polishing. A preferred example of the concentration (content) of silica particles is preferably 0.1% by mass or more and 50% by mass or less, more preferably 0.5% by mass or more and 40% by mass or less, even more preferably 1% by mass or more and 35% by mass or less, even more preferably 2% by mass or more and 30% by mass or less, particularly preferably 5% by mass or more and 25% by mass or less, and most preferably 10% by mass or more and 20% by mass or less, based on the total mass of the polishing composition.Silica particles can be used alone or in combination of two or more types.When two or more types of silica particles are used, the concentration (content) of the silica particles is the total amount.

[0076] The silica particles are preferably colloidal silica. Methods for producing colloidal silica include the sodium silicate method and the sol-gel method, and colloidal silica produced by either method can be suitably used. The irregularity N of the silica particles (preferably colloidal silica) can be appropriately controlled to 1.5 or more by selecting the production conditions (e.g., reaction temperature, reaction concentration, etc.). Commercially available silica particles may also be used. In this case, the irregularity N of the silica particles can be measured to select the silica particles to be used in the polishing composition of the second embodiment.

[0077] In addition, the D of silica particles 10 , D 50 , and D 90 This can also be appropriately controlled by selecting the conditions for producing the silica particles.

[0078] [Polishing accelerator] The polishing composition of the second embodiment contains a polishing accelerator. The polishing accelerator is one or more selected from the group consisting of aluminum salts of monovalent acids, pyrrolidone compounds, and caprolactam compounds. The polishing accelerator has the effect of assisting polishing by abrasive grains.

[0079] Examples of aluminum salts of monovalent acids include aluminum salts of monovalent inorganic acids or monovalent organic acids. Specific examples of monovalent inorganic acids include nitric acid, hydrochloric acid, perchloric acid, nitrous acid, hypochlorous acid, hypophosphorous acid (phosphinic acid; HPO(OH)), and sulfamic acid. Specific examples of monovalent organic acids include lactic acid, nicotinic acid, acetic acid, formic acid, propionic acid, valeric acid, caproic acid, caprylic acid, capric acid, cyclohexanecarboxylic acid, phenylacetic acid, benzoic acid, crotonic acid, methacrylic acid, methanesulfonic acid, ethanesulfonic acid, aminoethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, 1-naphthalenesulfonic acid, and 2-naphthalenesulfonic acid. When the aluminum salt of a monovalent acid contains water of hydration, the content of these acids excludes the water of hydration. Preferred examples of aluminum salts of monovalent acids include aluminum nitrate and aluminum chloride.

[0080] The concentration (content) of the aluminum salt of a monovalent acid in the polishing composition is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, particularly preferably 2% by mass or more, particularly preferably 3% by mass or more, and most preferably 5% by mass or more, relative to the total mass of the polishing composition. As the concentration of the aluminum salt of a monovalent acid increases, the polishing removal rate improves and thickness unevenness of the polished object can be reduced after polishing. Furthermore, the concentration (content) of the aluminum salt of a monovalent acid is preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 18% by mass or less, even more preferably 15% by mass or less, particularly preferably 12% by mass or less, and most preferably 10% by mass or less, relative to the total mass of the polishing composition. Within the above range, the polishing removal rate of the resin material can be further improved and thickness unevenness of the polished object can be reduced. A preferred example of the concentration (content) of the aluminum salt of a monovalent acid is preferably 0.1% by mass or more and 25% by mass or less, more preferably 0.5% by mass or more and 20% by mass or less, even more preferably 1% by mass or more and 18% by mass or less, even more preferably 2% by mass or more and 15% by mass or less, particularly preferably 3% by mass or more and 12% by mass or less, and most preferably 5% by mass or more and 10% by mass or less, based on the total mass of the polishing composition. The aluminum salt of a monovalent acid can be used alone or in combination of two or more. When two or more types of aluminum salts of a monovalent acid are used, the concentration (content) of the aluminum salt of a monovalent acid is the total amount.

[0081] Examples of pyrrolidone compounds include 2-pyrrolidone or 2-pyrrolidone derivatives, and polymers having structural units derived from 2-pyrrolidone derivatives. Examples of 2-pyrrolidone derivatives include 2-pyrrolidone, N-octyl-2-pyrrolidone, N-dodecyl-2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, N-butyl-2-pyrrolidone, N-hexyl-2-pyrrolidone, N-decyl-2-pyrrolidone, N-octadecyl-2-pyrrolidone, N-hexadecyl-2-pyrrolidone, and N-vinyl-2-pyrrolidone. Examples of polymers having structural units derived from 2-pyrrolidone derivatives include homopolymers (hereinafter also referred to as "polyvinylpyrrolidone" or "PVP") and copolymers of N-vinyl-2-pyrrolidone. These pyrrolidone compounds may be used alone or in combination of two or more. Among these, polyvinylpyrrolidone is preferred as the pyrrolidone compound.

[0082] The concentration (content) of the pyrrolidone compound in the polishing composition is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.003% by mass or more, even more preferably 0.005% by mass or more, particularly preferably 0.007% by mass or more, particularly preferably 0.008% by mass or more, and most preferably 0.01% by mass or more, relative to the total mass of the polishing composition. As the concentration of the pyrrolidone compound increases, the polishing removal rate is further improved and thickness unevenness of the polished object can be reduced after polishing. Furthermore, the concentration (content) of the pyrrolidone compound is preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1.5% by mass or less, even more preferably 1.2% by mass or less, particularly preferably 1% by mass or less, and most preferably 0.5% by mass or less, relative to the total mass of the polishing composition. Within the above range, the polishing removal rate of the resin material can be further improved and thickness unevenness of the polished object can be reduced after polishing. A preferred example of the concentration (content) of the pyrrolidone compound is, relative to the total mass of the polishing composition, preferably 0.001% by mass or more and 3% by mass or less, more preferably 0.003% by mass or more and 2% by mass or less, even more preferably 0.005% by mass or more and 1.5% by mass or less, particularly preferably 0.007% by mass or more and 1.2% by mass or less, particularly preferably 0.008% by mass or more and 1% by mass or less, and most preferably 0.01% by mass or more and 0.5% by mass or less. When two or more pyrrolidone compounds are used, the concentration (content) of the pyrrolidone compounds is the total amount.

[0083] In one embodiment of the second polishing composition, the pyrrolidone compound is polyvinylpyrrolidone. In this case, the weight-average molecular weight (Mw) of the polyvinylpyrrolidone is preferably 2,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, and particularly preferably 7,500 or more. The weight-average molecular weight (Mw) of the polyvinylpyrrolidone is preferably 900,000 or less, more preferably 500,000 or less, even more preferably 250,000 or less, particularly preferably 100,000 or less, and most preferably 55,000 or less. Polyvinylpyrrolidone with a weight-average molecular weight within the above range can more efficiently improve the polishing removal rate of resin materials and reduce thickness unevenness of the polished object after polishing.

[0084] Examples of the caprolactam compound include ε-caprolactam or its derivatives, and polymers having structural units derived from ε-caprolactam or its derivatives. Caprolactam compounds can be used as a substitute for pyrrolidone compounds. Examples of the caprolactam compound include ε-caprolactam, nylon 6, etc.

[0085] The concentration (content) of the caprolactam compound in the polishing composition is not particularly limited, but is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, and even more preferably 0.1 mass% or more, based on the total mass of the polishing composition.Furthermore, the concentration (content) of the caprolactam compound is preferably 5 mass% or less, more preferably 2 mass% or less, and even more preferably 1 mass% or less.If the content of the caprolactam compound is within the above range, it can more efficiently improve the polishing removal rate of the resin material and reduce the thickness unevenness of the polished object after polishing.

[0086] The pyrrolidone compound and the caprolactam compound may be commercially available products or may be synthesized by a known method.

[0087] According to one embodiment, in the polishing composition of the second form, the polishing accelerator includes an aluminum salt of a monovalent acid and a pyrrolidone compound. By including an aluminum salt of a monovalent acid and a pyrrolidone compound as the polishing accelerator in the polishing composition according to the second form, it is possible to more efficiently improve the polishing removal rate of the resin material and reduce the thickness unevenness of the object to be polished after polishing.

[0088] [Water] The polishing composition according to the second form contains water. Water disperses or dissolves each component. 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, pure water or ultrapure water obtained by removing impurity ions with an ion exchange resin and then removing foreign substances through a filter, or distilled water is preferable. Further, for the purpose of controlling the dispersibility of other components in the polishing composition, an organic solvent or the like as a dispersion medium may be further included.

[0089] The compositions of the main components included in the polishing composition according to the first form and the polishing composition according to the second form are as described above. The following "other components" are commonly applied to the polishing composition according to the first form and the polishing composition according to the second form.

[0090] [Other Components] The polishing composition according to this form may further contain known components such as a pH adjuster, a surfactant, a dispersant, a thickener (viscosity adjuster), a surface protector, a wetting agent, a water-soluble polymer (excluding polymers having structural units derived from 2-pyrrolidone), a salt (excluding aluminum salts of monovalent acids), a preservative, a fungicide, etc. (hereinafter, "other components") within a range that does not impair the effects of the present invention. The content of these other components may be appropriately set according to the purpose of addition. Hereinafter, the pH adjuster, the surfactant, the dispersant, the thickener (viscosity adjuster), the oxidizing agent, the anticorrosive agent, the preservative, the fungicide, and the chelating agent will be described.

[0091] <pH Adjuster> The polishing composition according to this embodiment may further contain a pH adjuster, which can contribute to adjusting the pH of the polishing composition by selecting the type and amount of the pH adjuster.

[0092] 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.

[0093] The acid may be either an inorganic acid or an organic acid. Inorganic acids include, but are not limited to, sulfuric acid, nitric acid, hydrochloric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. Organic acids include, but are not limited to, 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, with malic acid, citric acid, and maleic acid being more preferred. When an inorganic acid is used, nitric acid, sulfuric acid, or phosphoric acid is preferred.

[0094] The alkali is not particularly limited, but examples thereof include hydroxides of alkali metals, salts of alkali metals, hydroxides of alkaline earth metals, salts of alkaline earth metals, quaternary ammonium, and ammonia.

[0095] Specific examples of alkali metals include potassium and sodium. Specific examples of alkaline earth metals include calcium and strontium. Specific examples of salts include carbonates, bicarbonates, sulfates, acetates, and the like. Specific examples of quaternary ammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium, and hydroxides thereof. Of these, potassium hydroxide or ammonia is preferred as the alkali.

[0096] The pH adjusters may be used singly or in combination of two or more.

[0097] The pH of the polishing composition according to this embodiment is not particularly limited, but is preferably 8 or less, more preferably 7 or less, even more preferably 6 or less, particularly preferably 5 or less, and most preferably 4 or less. According to one embodiment, the pH of the polishing composition according to this embodiment may be 3.5 or less, 3 or less, or less than 3. If the pH of the polishing composition is within the above range, it is possible to more efficiently improve the polishing removal rate of the resin material and reduce thickness unevenness of the polished object after polishing. Furthermore, the pH is preferably 1 or more, more preferably 1.5 or more. For example, the pH of the polishing composition is preferably 1 to 8 or less, more preferably 1 to 7 or less, even more preferably 1 to 6 or less, particularly preferably 1 to 5 or less, and most preferably 1 to 4 or less. According to one embodiment, the pH of the polishing composition is 1.0 to 6.0, 1.0 to 5.0, 1.5 to 4.5, 1.5 to 4.0, 2.0 to 5.0, 2.0 to 4.5, 2.0 to 4.0, or 1.0 to 3.5. The content of the pH adjuster is not particularly limited, and is preferably an amount that allows the pH value to fall within the above-mentioned preferred range.

[0098] <Surfactant> The polishing composition according to some embodiments of the present invention may contain a surfactant. The surfactant that can be contained in the polishing composition according to this embodiment is at least one selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Of these, nonionic surfactants are preferred as the surfactant contained in the polishing composition. The surfactants can be used alone or in combination of two or more.

[0099] Examples of anionic surfactants include polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, alkyl ether sulfates, alkylbenzenesulfonic acids, alkyl phosphates, polyoxyethylene alkyl phosphates, polyoxyethylene sulfosuccinic acids, alkyl sulfosuccinic acids, alkylnaphthalenesulfonic acids, alkyldiphenyletherdisulfonic acids, and salts thereof.

[0100] Examples of cationic surfactants include alkyltrimethylammonium salts, alkyldimethylammonium salts, alkylbenzyldimethylammonium salts, and alkylamine salts.

[0101] Examples of amphoteric surfactants include alkyl betaines and alkyl amine oxides.

[0102] Examples of nonionic surfactants include polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, and alkylalkanolamides.

[0103] When the polishing composition contains a surfactant, the content of the surfactant is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, based on the total mass of the polishing composition.Furthermore, the content of the surfactant in the polishing composition is preferably 3.0 mass% or less, more preferably 2.0 mass% or less, based on the total mass of the polishing composition.If the content of the surfactant is within the above range, the polishing uniformity of the object to be polished is further improved.

[0104] <Dispersant / Thickener (Viscosity Adjuster)> The polishing composition according to this embodiment may contain a dispersant or thickener (viscosity modifier). The dispersant or thickener serves to uniformly disperse the abrasive grains (silica particles) in the liquid, thereby allowing the abrasive grains to act efficiently on the object to be polished. In addition, the presence of the dispersant or thickener between the abrasive grains is expected to suppress caking of the abrasive grains, thereby suppressing the occurrence of scratches caused by agglomerated abrasive grains.

[0105] Specific examples of dispersants include colloidal substances containing fine particles, such as colloidal alumina, colloidal zirconia, colloidal titania, alumina sol, zirconia sol, titania sol, fumed alumina, fumed zirconia, fumed titania, etc. Also, commonly used dispersants such as sodium phosphate, sodium hexametaphosphate, and sodium pyrophosphate may be used.

[0106] Specific examples of thickeners include glycols such as propylene glycol polymers and ethylene glycol polymers, and polymeric compounds. More specifically, glycols include propylene glycol, ethylene glycol, dipropylene glycol, polypropylene glycol, diethylene glycol, and polyethylene glycol. Polymeric compounds include sodium polyacrylate, polyvinyl alcohol, and hydroxyethyl cellulose.

[0107] [Polishing removal speed] The polishing composition of this embodiment can improve the polishing removal rate of resin materials. For example, the polishing removal rate of resin materials is preferably 140 nm / min or more, more preferably 150 nm / min or more, and even more preferably 170 nm / min or more. The polishing removal rate can be measured by the method described in Examples.

[0108] [Thickness Unevenness] The polishing composition of this embodiment can maintain or improve the flatness of the object to be polished. That is, the polishing composition of this embodiment can reduce thickness unevenness of the object to be polished that may occur during polishing. Thickness unevenness can be evaluated using GBIR. For example, the thickness unevenness of the object to be polished (polished object) after polishing with the polishing composition of this embodiment is preferably less than 2.0 μm, more preferably 1.5 μm or less, even more preferably 1.2 μm or less, and particularly preferably 0.8 μm or less. Therefore, in one embodiment, the flatness defined by GBIR of the polished object to be polished using the polishing composition of this embodiment can be less than 2.0 μm (preferably 1.5 μm or less, more preferably 1.2 μm or less, and even more preferably 0.8 μm or less). GBIR can be measured by the method described in the Examples.

[0109] Surface roughness (Rms) The polishing composition of this embodiment can maintain or improve the surface roughness of the object to be polished. That is, the polishing composition of this embodiment can reduce the surface roughness of the object to be polished that may occur during polishing. The surface roughness of the object to be polished can be evaluated using the root mean square height (Rms), a parameter that evaluates the variation in unevenness relative to a reference surface. For example, the root mean square height (Rms) of the object to be polished (polished object) after polishing with the polishing composition of this embodiment is preferably less than 1.5 nm, more preferably 1.2 nm or less, even more preferably 1.0 nm or less, particularly preferably 0.8 nm or less, and most preferably 0.5 nm or less. The lower limit of the surface roughness defined by the root mean square height (Rms) of the polished object to be polished is not particularly limited, but in practice it is, for example, 0.01 nm or more. Therefore, in one embodiment, the polishing composition of this embodiment can provide a surface roughness of the polished object, defined by the root mean square height (Rms), of 1.0 nm or less (preferably 0.5 nm or less). The root mean square height (Rms) can be measured by the method described in the Examples.

[0110] [Method for producing polishing composition] In the polishing composition of this embodiment, the manufacturing method (preparation method) of the polishing composition is not particularly limited, and for example, can suitably adopt the manufacturing method that comprises: silica particles; if necessary, polishing accelerator (one or more selected from the group consisting of aluminum salt of monovalent acid, pyrrolidone compound and caprolactam compound); if necessary, other components; stirring and mixing.In addition, silica particles, water, polishing accelerator and other components are the same as those described above, so description here is omitted.

[0111] The temperature at which the components of the polishing composition are mixed is not particularly limited, but is preferably 10° C. to 40° C. Heating may be performed to increase the dissolution rate. The mixing time is also not particularly limited.

[0112] [Polishing method] Another aspect of the present invention relates to a polishing method, which comprises a step of polishing an object to be polished, comprising a resin material, using the above-mentioned polishing composition. The polishing step is not limited to being performed after a lapping step, and may be performed after a cutting step or a grinding step. Preferred examples of the object to be polished in the polishing method according to this aspect are the same as those listed in the description of [Object to be polished].

[0113] The third aspect of the present invention is a polishing method for polishing a polishing object containing a resin material using the polishing composition according to the first aspect. Therefore, according to the third aspect of the present invention, the method comprises supplying the polishing composition between the polishing object containing a resin material and a polishing pad to polish the polishing object, wherein the polishing composition contains silica particles and water, and the silica particles have an average particle diameter D 50 is 50 nm or more.

[0114] The fourth aspect of the present invention is a polishing method for polishing a resin material-containing object to be polished using the polishing composition according to the second aspect.Accordingly, the fourth aspect of the present invention comprises supplying a polishing composition between a resin material-containing object to be polished and a polishing pad to polish the object to be polished, the polishing composition comprises silica particles, a polishing accelerator, and water, the polishing accelerator is one or more selected from the group consisting of aluminum salts of monovalent acids, pyrrolidone compounds, and caprolactam compounds, and the particle diameter of the silica particles at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 50% is defined as D. 50 The BET specific surface area is SA, and the D 50 The polishing method provides a non-circularity N of 1.5 or more, where SA' is the theoretical specific surface area calculated from the above formula: N=SA / SA'.

[0115] In the polishing method according to the present embodiment, polishing of 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 a polishing composition is supplied from above while 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 a platen with a polishing pad attached is pressed against the opposite side of the object to be polished while a polishing composition is supplied from above while the platen is rotated relative to the other side 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 fabric pads, polyurethane pads, and suede pads can be used without particular limitations as polishing pads. It is preferable that the polishing pad be treated to allow the polishing liquid to accumulate.

[0116] Polishing conditions for the polishing method according to this embodiment include, for example, polishing load, platen rotation speed, carrier rotation speed, flow rate of the polishing composition, and polishing time. These polishing conditions are not particularly limited. 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, and more preferably 0.5 psi (3.5 kPa) or more and 5.0 psi (35 kPa) or less. Generally, the higher the load, the higher the frictional force of the abrasive grains, improving the mechanical processing force and thereby increasing the polishing removal rate. Within this range, a sufficient polishing removal 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 supply amount of the polishing composition may be a supply amount (flow rate) sufficient to cover 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 also not particularly limited. For example, a method of continuously supplying the polishing composition using a pump or the like can be used. The processing time is not particularly limited as long as it is a time that can obtain the desired processing results, but it is preferable to set it to a shorter time due to the high polishing removal rate.

[0117] Here, the surface of the object to be polished is generally finished into a flat surface with little thickness unevenness and a smooth surface with few defects through a lapping step and a polishing step. The polishing step includes one or more polishing steps selected from the group consisting of a rough polishing step (preliminary polishing step), a middle polishing step (intermediate polishing step), and a fine polishing step (finish polishing step). That is, the polishing step can be composed of multiple polishing steps. The polishing method according to this embodiment using the above polishing composition is suitable for the middle polishing step and the fine polishing step, and can be particularly suitable for the fine polishing step. The polishing method according to this embodiment (i.e., fine polishing) can be performed, for example, after the rough polishing step and the middle polishing step, or the middle polishing step can be omitted and the polishing method can be performed after the rough polishing step.

[0118] In each polishing step, including the rough polishing step, the middle polishing step, and the fine polishing step, the polishing characteristics required for each polishing step are different.Therefore, depending on the stage of the polishing step (i.e., whether it is the rough polishing step, the middle polishing step, or the fine polishing step), different polishing compositions (such as the type of abrasive grains, the type and content of components such as the particle diameter of the abrasive grains, etc.); different polishing conditions (such as the polishing pad, the polishing pressure, the amount (flow rate) of the polishing composition used, etc.); etc. can be adopted.

[0119] In one embodiment, in the rough polishing step, the object to be polished is preferably polished using a double-sided polishing machine that simultaneously polishes both sides of the substrate from the viewpoint of reducing thickness unevenness. Also, in one embodiment, in the rough polishing step, from the viewpoint of reducing thickness unevenness, the polishing pad is preferably a nonwoven fabric pad, a polyurethane pad, or a suede pad, more preferably a nonwoven fabric pad or a polyurethane pad, and most preferably a polyurethane pad.

[0120] According to one embodiment, the polishing load in the rough polishing step 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 5.0 psi (35 kPa) or less. According to one embodiment, the supply rate of the polishing composition in the rough polishing step (also referred to as the flow rate of the polishing composition or the slurry flow rate) is not particularly limited, but is preferably, for example, 1 (mL / min) or more and 300 (mL / min) or less, 1 (mL / min) or more and 200 (mL / min) or less, 1 (mL / min) or more and 150 (mL / min) or less, 1 (mL / min) or more and 100 (mL / min) or less, or 1 (mL / min) or more and 50 (mL / min) or less.

[0121] In one embodiment, the Shore A hardness of the polishing pad in the rough polishing step is preferably 98° or less, more preferably 95° or less. The lower limit of the Shore A hardness of the polishing pad in the rough polishing step is preferably 60° or more, more preferably 70° or more, and even more preferably 80° or more. According to one embodiment, the Shore A hardness may be 60° or more and 98° or less, or 70° or more and 98° or less, or 70° or more and 95° or less, or 80° or more and 98° or less, or 80° or more and 95° or less. When the Shore A hardness of the polishing pad used in the rough polishing step is within the above range, the polishing pad and the object to be polished come into contact with each other with appropriate pressure, which improves the polishing removal rate of the resin material and reduces thickness unevenness of the object to be polished after polishing. The Shore A hardness of the polishing pad is a value measured using a Type A durometer in accordance with JIS K 6253-3:2012.

[0122] According to one embodiment, in the manufacturing method of this embodiment, the object to be polished may be polished with a polishing composition containing alumina particles as abrasive grains in the rough polishing step. In this case, the average primary particle diameter D of the alumina particles 50 is preferably 0.1 μm or more and 5.0 μm or less.

[0123] According to one embodiment, the rough polishing step can produce a polished object (roughly polished object) having a thickness of preferably 0.10 mm to 0.80 mm, more preferably 0.10 mm to 0.60 mm, and even more preferably 0.10 mm to 0.55 mm. Furthermore, according to one embodiment, the rough polishing step can produce a polished object (roughly polished object) having a surface with a GBIR of preferably 1.5 μm or less, more preferably 1.0 μm or less, and even more preferably less than 0.5 μm. According to one embodiment, the rough polishing step can produce a polished object (roughly polished object) having a surface with defects of a depth of 100 nm or more remaining.

[0124] In one embodiment, a middle polishing step is performed after the rough polishing step. In the middle polishing step, the object to be polished is preferably polished using a double-sided polishing machine that simultaneously polishes both sides of the substrate from the viewpoint of reducing thickness unevenness. In one embodiment, the polishing pad in the middle polishing step is preferably a nonwoven fabric pad, a polyurethane pad, or a suede pad from the viewpoint of reducing thickness unevenness, with a nonwoven fabric pad and a polyurethane pad being particularly preferred, and a polyurethane pad being most preferred.

[0125] According to one embodiment, the polishing load in the middle polishing step is preferably 0.1 psi (0.69 kPa) to 10 psi (69 kPa) per unit area of ​​the object to be polished, and more preferably 0.5 psi (3.5 kPa) to 5.0 psi (35 kPa). According to one embodiment, the supply rate of the polishing composition in the middle polishing step is preferably, for example, 1 mL / min to 300 mL / min, 1 mL / min to 200 mL / min, 1 mL / min to 150 mL / min, 1 mL / min to 100 mL / min, or 1 mL / min to 50 mL / min.

[0126] According to one embodiment, in the manufacturing method of this aspect, the object to be polished may be one that has been polished with the polishing composition in the middle polishing step.

[0127] In one embodiment, the Shore A hardness of the polishing pad in the middle polishing step is preferably 90° or less, more preferably 85° or less, even more preferably 82° or less, even more preferably 80° or less, particularly preferably 78° or less, and most preferably 75° or less. The lower limit of the Shore A hardness of the polishing pad in the middle polishing step is preferably 10° or more, more preferably 20° or more, even more preferably 30° or more, particularly preferably 40° or more, and most preferably 50° or more. According to one embodiment, it may be 60° or more and 80° or less, 65° or more and 80° or less, or 68° or more and 80° or less. When the Shore A hardness of the polishing pad used in the middle polishing step is within the above range, the polishing pad and the object to be polished come into contact with each other with an appropriate pressure, which improves the polishing removal rate of the resin material and further reduces unevenness in the thickness of the object to be polished after polishing. The Shore A hardness of the polishing pad is a value measured based on a Type A durometer in accordance with JIS K 6253-3:2012.

[0128] According to one embodiment, the intermediate polishing step can produce a polished object (polished object after intermediate polishing) having a thickness of preferably 0.10 mm to 0.80 mm, more preferably 0.10 mm to 0.60 mm, and even more preferably 0.10 mm to 0.55 mm. Furthermore, according to one embodiment, the intermediate polishing step can produce a polished object (polished object after intermediate polishing) having a surface with a GBIR of preferably 1.5 μm or less, more preferably 1.0 μm or less, and even more preferably less than 0.5 μm. According to one embodiment, the intermediate polishing step can produce a polished object (polished object after intermediate polishing) having a surface with defects of 70 nm or less in depth. That is, the polishing method according to this embodiment can reduce defects in the polished object and produce a polished object (polished object after polishing) with reduced scratches of less than 100 nm in depth.

[0129] After the above-mentioned rough polishing step, or the rough polishing step and the medium polishing step, the fine polishing step is carried out using the above-mentioned polishing composition, whereby the resin material can be polished at high speed and the thickness unevenness can be suppressed to obtain a polished object. Therefore, according to one embodiment, the manufacturing method of this form, the polished object containing the resin material has been subjected to the rough polishing step, or the rough polishing step and the medium polishing step.

[0130] In one embodiment, in the fine polishing step, the object to be polished is preferably polished using a double-sided polishing machine that simultaneously polishes both sides of the substrate from the viewpoint of reducing thickness unevenness. Also, in one embodiment, in the fine polishing step, a polyurethane pad or a suede pad is preferably used as the polishing pad, and a suede pad is more preferably used.

[0131] In one embodiment, in the fine polishing step, the Shore A hardness of the polishing pad is preferably 90° or less, more preferably 85° or less, even more preferably 82° or less, even more preferably 80° or less, particularly preferably 78° or less, and most preferably 75° or less. The lower limit of the Shore A hardness of the polishing pad is preferably 10° or more, more preferably 20° or more, even more preferably 30° or more, particularly preferably 40° or more, particularly more preferably 45° or more, and most preferably 50° or more. According to one embodiment, it may be 45° or more to 80° or less, 50° or more to 80° or less, 60° or more to 80° or less, 65° or more to 80° or less, or 68° or more to 80° or less. When the Shore A hardness of the polishing pad used in the fine polishing step is within the above range, the polishing pad and the object to be polished come into contact with each other with an appropriate pressure, which improves the polishing removal rate of the resin material and better reduces uneven thickness of the object to be polished after polishing.

[0132] According to one embodiment, the polishing load in the fine polishing step 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, and more preferably 0.5 psi (3.5 kPa) or more and 5.0 psi (35 kPa) or less. According to one embodiment, the supply rate of the polishing composition in the fine polishing step is preferably 1 (mL / min) or more and 50 (mL / min) or less, more preferably 3 (mL / min) or more and 45 (mL / min) or less, even more preferably 5 (mL / min) or more and 40 (mL / min) or less, and particularly preferably 8 (mL / min) or more and 30 (mL / min) or less. If the supply rate of the polishing composition in the fine polishing step is within the above range, thickness unevenness can be reduced. The smaller the supply rate of the polishing composition, the better the thickness unevenness is improved, and also, in terms of the amount of polishing composition used, the cost can be reduced, which is preferable.

[0133] According to one embodiment, the fine polishing step can produce a polished object (fine-polished object) having a thickness of, for example, 0.10 mm to 0.90 mm, preferably 0.10 mm to 0.80 mm, more preferably 0.10 mm to 0.60 mm, and even more preferably 0.10 mm to 0.55 mm. Furthermore, according to one embodiment, the fine polishing step can produce a polished object (fine-polished object) having a surface with a GBIR of preferably 1.5 μm or less, more preferably 1.0 μm or less, and even more preferably less than 0.5 μm. According to one embodiment, the fine polishing step can produce a polished object (fine-polished object) having a surface with defects of 70 nm or less in depth. That is, the polishing method according to this embodiment can reduce defects in the polished object and produce a polished object (fine-polished object) with reduced scratches of less than 100 nm in depth.

[0134] Furthermore, still another aspect of the present invention relates to a method for producing a polished object, which comprises a step of polishing an object by the above-mentioned polishing method. Preferred examples of the object to be polished according to this aspect are the same as those described in the description of [Object to be polished]. A preferred example is a method for producing a polished object made of an optical resin material. and a method for producing an optical member, which comprises a step of polishing by the polishing method.

[0135] [Polishing System] Yet another aspect of the present invention relates to a polishing system comprising the above polishing composition, an object to be polished containing a resin material, and a polishing pad.

[0136] The fifth aspect of the present invention is a polishing system comprising the polishing composition according to the first aspect, an object to be polished comprising a resin material, and a polishing pad.Accordingly, the fifth aspect of the present invention is a polishing system comprising an object to be polished comprising a resin material, a polishing pad, and a polishing composition, wherein the polishing composition contains silica particles and water; the silica particles have an average particle diameter D 50 is 50 nm or more; and the surface of the object to be polished is contacted with the polishing pad and the polishing composition.

[0137] The sixth aspect of the present invention is a polishing system comprising the polishing composition according to the second aspect, a polishing object comprising a resin material, and a polishing pad.Accordingly, according to the sixth aspect of the present invention, the polishing system comprises a polishing object comprising a resin material, a polishing pad, and a polishing composition, wherein the polishing composition comprises silica particles, a polishing accelerator, and water; the polishing accelerator is one or more selected from the group consisting of aluminum salts of monovalent acids, pyrrolidone compounds, and caprolactam compounds; and the particle diameter of the silica particles at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 50% is defined as D. 50 The BET specific surface area is SA, and the D 50where SA' is the theoretical specific surface area calculated from the above formula, the irregularity N, expressed as N=SA / SA', is 1.5 or more; and the surface of the object to be polished is brought into contact with the polishing pad and the polishing composition.

[0138] The preferred embodiments of the object to be polished and the polishing composition to be applied to the polishing system according to this embodiment are the same as those described above, and therefore, description thereof will be omitted.

[0139] The polishing system of this embodiment may be one in which both sides of the object to be polished are brought into contact with the polishing pad and the polishing composition, thereby polishing both sides of the object to be polished simultaneously, or one in which only one side of the object to be polished is brought into contact with the polishing pad and the polishing composition, thereby polishing only one side of the object to be polished.

[0140] In the polishing system according to this embodiment, a working slurry containing the polishing composition is prepared. The polishing composition is then supplied to an object to be polished, and polished in a conventional manner. For example, the object to be polished is placed in a conventional polishing apparatus, and the polishing composition is supplied to the surface of the object to be polished (the surface to be polished) through the polishing pad of the polishing apparatus. Typically, the polishing pad is pressed against the surface of the object to be polished, and the two are moved relative to each other (for example, rotated). Through this polishing process, polishing of the object to be polished is completed.

[0141] The polishing pad used in the polishing system according to this embodiment can be a nonwoven fabric pad, a polyurethane pad, or a suede pad. Of these, the polishing pad is preferably a polyurethane pad or a suede pad, and more preferably a suede pad from the viewpoint of further reducing defects.

[0142] In the polishing system according to this embodiment, the pressure when the polishing pad and the polishing composition are brought into contact, i.e., the polishing load, is preferably 0.1 psi (0.69 kPa) or more and 10 psi (69 kPa) or less, and more preferably 0.5 psi (3.5 kPa) or more and 5.0 psi (35 kPa) or less per unit area of ​​the object to be polished. According to one embodiment, in the polishing system according to this embodiment, the supply rate of the polishing composition is preferably 1 (mL / min) or more and 50 (mL / min) or less, more preferably 3 (mL / min) or more and 45 (mL / min) or less, even more preferably 5 (mL / min) or more and 40 (mL / min) or less, and particularly preferably 8 (mL / min) or more and 30 (mL / min) or less.

[0143] In one embodiment of the polishing system according to this aspect, the Shore A hardness of the polishing pad is preferably 90° or less, more preferably 85° or less, even more preferably 82° or less, even more preferably 80° or less, particularly preferably 78° or less, and most preferably 75° or less. The lower limit of the Shore A hardness of the polishing pad is preferably 10° or more, more preferably 20° or more, even more preferably 30° or more, particularly preferably 40° or more, particularly more preferably 45° or more, and most preferably 50° or more. In one embodiment, the Shore A hardness may be 45° or more and 80° or less, 50° or more and 80° or less, 60° or more and 80° or less, 65° or more and 80° or less, or 68° or more and 80° or less. In the polishing system according to this aspect, the Shore A hardness of the polishing pad is within the above range, so that the polishing pad and the workpiece come into contact with each other with an appropriate pressure, which improves the polishing removal rate of the resin material and further reduces uneven thickness of the workpiece after polishing.

[0144] Although the embodiments of the present invention have been described in detail, it is clear that this is by way of illustration and example only and not of limitation, and that the scope of the present invention should be interpreted by the appended claims.

[0145] The present invention also encompasses the following aspects and configurations: [1] A polishing composition used for polishing an object to be polished containing a resin material, comprising silica particles and water, wherein the silica particles have an average particle diameter D 50 a polishing composition having a particle size of 50 nm or more: [2] Further containing an abrasion accelerator, The polishing composition according to the above-mentioned [1], wherein the polishing accelerator is at least one selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound. [3] In the silica particles, the particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 50% is defined as D 50 The BET specific surface area is SA, and the D 50 The polishing composition according to the above [1] or [2], wherein the irregularity N, expressed as N=SA / SA', is 1.2 or more, where SA' is the theoretical specific surface area calculated from the above: [4] The silica particles have an average particle diameter D 50 The polishing composition according to any one of the above [1] to [3], wherein the average particle size is 50 nm or more and less than 200 nm. [5] The polishing composition according to any one of the above [2] to [4], wherein the polishing accelerator contains the aluminum salt of the monovalent acid and the pyrrolidone compound. [6] The particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution of the silica particles is 10% is defined as D 10 The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution of the silica particles is 90% is defined as D 90 When D 10 D against 90 The ratio (D 90 / D 10 ) is 2.0 or more. [7] The polishing composition according to any one of the above [1] to [6], wherein the resin material is an optical resin material. [8] The polishing composition according to any one of [1] to [7] above, wherein the object to be polished has an average thickness of 1 mm or less before polishing. [9] The polishing composition according to any one of the above [1] to [8], wherein the flatness of the object to be polished as defined by GBIR after polishing is 1.5 μm or less.

[10] A polishing composition used for polishing an object to be polished, including a resin material, comprising silica particles, a polishing accelerator, and water, wherein the polishing accelerator is one or more selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound, and the silica particles have a particle size D at which the cumulative frequency from the small particle size side in the volume-based particle size distribution of the silica particles is 50%. 50 The BET specific surface area is SA, and the D 50 wherein SA' is the theoretical specific surface area calculated from the above formula, and the irregularity N, expressed as N=SA / SA', is 1.5 or more:

[11] A polishing method comprising a step of polishing an object containing a resin material with the polishing composition according to any one of [1] to

[10] above:

[12] A method for producing an optical member, comprising a step of polishing an optical resin material by the polishing method according to

[11] above:

[13] A method for polishing an object to be polished by supplying a polishing composition between an object to be polished containing a resin material and a polishing pad, wherein the polishing composition contains silica and water, and the silica particles have an average particle diameter D 50 is 50nm or more, polishing method:

[14] The polishing method according to

[13] above, wherein the polishing pad has a Shore A hardness of 40 or more.

[15] The polishing method according to

[13] or

[14] above, wherein the polishing composition further contains a polishing accelerator, and the polishing accelerator is at least one selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound:

[16] In the silica particles, the particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 50% is defined as D 50 The BET specific surface area is SA, and the D 50The polishing method according to any one of the above items

[13] to

[15] , wherein the irregularity N, expressed as N=SA / SA', is 1.2 or more, where SA' is the theoretical specific surface area calculated from the above formula:

[17] The silica particles have an average particle diameter D 50 The polishing method according to any one of the above

[13] to

[16] , wherein the surface roughness is 50 nm or more and less than 200 nm.

[18] The polishing method according to any one of the above items

[13] to

[17] , wherein the flatness of the object after polishing, as defined by GBIR, is 1.5 μm or less.

[19] A polishing system including an object to be polished containing a resin material, a polishing pad, and a polishing composition, wherein the polishing composition contains silica particles and water; and the silica particles have an average particle diameter D 50 a polishing system in which the surface of the object to be polished is contacted with the polishing pad and the polishing composition;

[20] A polishing system comprising an object to be polished containing a resin material, a polishing pad, and a polishing composition, wherein the polishing composition contains silica particles, a polishing accelerator, and water; The polishing accelerator is at least one selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound; and the silica particles have a particle size D where the cumulative frequency from the small particle size side in the volume-based particle size distribution of the silica particles is 50%. 50 The BET specific surface area is SA, and the D 50 wherein the irregularity N, expressed as N=SA / SA', is 1.5 or more, where SA' is the theoretical specific surface area calculated from the above formula (2), and the surface of the object to be polished is brought into contact with the polishing pad and the polishing composition;

[21] The polishing system according to

[19] or

[20] above, wherein the polishing pad has a Shore A hardness of 40 or more.

[0146] The present invention also encompasses the following aspects and configurations: [1] A polishing composition used for polishing an object to be polished, including a resin material, comprising silica particles, a polishing accelerator, and water, wherein the polishing accelerator is one or more selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound, and the silica particles have a particle size D where the cumulative frequency from the small particle size side in the volume-based particle size distribution of the silica particles is 50%. 50 The BET specific surface area is SA, and the D 50 wherein SA' is the theoretical specific surface area calculated from the above formula, and the irregularity N, expressed as N=SA / SA', is 1.5 or more: [2] The polishing composition according to [1] above, wherein the polishing accelerator comprises an aluminum salt of the monovalent acid and the pyrrolidone compound. [3] The particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution of the silica particles is 10% is defined as D 10 The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution of the silica particles is 90% is defined as D 90 When D 10 D against 90 The ratio (D 90 / D 10 ) is 2.0 or more. [4] The polishing composition according to any one of the above [1] to [3], wherein the resin material is an optical resin material. [5] The polishing composition according to any one of [1] to [4] above, wherein the object to be polished has an average thickness of 1 mm or less before polishing. [6] The polishing composition according to any one of [1] to [5] above, wherein the flatness of the object to be polished as defined by GBIR after polishing is 1.5 μm or less. [7] A polishing method comprising a step of polishing an object to be polished containing a resin material with the polishing composition according to any one of [1] to [6] above: [8] A method for producing an optical member, comprising a step of polishing an optical resin material by the polishing method according to [7] above: [9] A polishing system including an object to be polished containing a resin material, a polishing pad, and a polishing composition, wherein the polishing composition contains silica particles, a polishing accelerator, and water; the polishing accelerator is one or more selected from the group consisting of aluminum salts of monovalent acids, pyrrolidone compounds, and caprolactam compounds; and the particle diameter of the silica particles at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 50% is defined as D. 50 The BET specific surface area is SA, and the D 50 wherein the irregularity N, expressed as N=SA / SA', is 1.5 or more, where SA' is the theoretical specific surface area calculated from the above formula (2), and the surface of the object to be polished is brought into contact with the polishing pad and the polishing composition;

[10] The polishing system described in [9] above, wherein the polishing pad is a suede pad. [Example]

[0147] Examples of the present invention will be described below. 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.

[0148] (Preparation of Polishing Compositions of Examples 1 to 17 and Comparative Examples 1 and 2) The polishing compositions of Examples 1 to 3 and Comparative Example 1 were prepared by mixing the colloidal silica in the amount shown in Table 1 with the remaining amount of water, assuming the total mass of the composition to be 100 (mixing temperature: approximately 25°C, mixing time: approximately 30 minutes). The polishing compositions of Examples 4 to 17 and Comparative Example 2 were prepared by mixing the colloidal silica in the amount shown in Table 2 with the polishing accelerator in the amount shown in Table 2 and the remaining amount of water, assuming the total mass of the composition to be 100 (mixing temperature: approximately 25°C, mixing time: approximately 30 minutes). The polishing accelerator was added in an amount of 8% by mass when aluminum nitrate was contained, and in an amount of 0.01% by mass when polyvinylpyrrolidone was contained. The weight-average molecular weight of polyvinylpyrrolidone was 45,000.

[0149] The volume-based average primary particle size of the silica particles used as abrasive grains and the pH of each polishing composition are shown in Tables 1 and 2. In Tables 1 and 2, "-" indicates that the component is not contained.

[0150] For the polishing composition obtained above, the physical properties of the silica particles were evaluated, and the polishing removal rate of the object to be polished (episulfide-based resin substrate) and scratches on the surface of the object to be polished (thiourethane-based resin substrate surface) were evaluated according to the methods described below.

[0151] [evaluation] <D of silica particles 10 , D 50 , D 90 > The silica particles were measured using a laser diffraction 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 10% was determined as the D of the silica particles. 10 The particle size at which the cumulative frequency from the small particle size side becomes 50% is called D 50 The particle diameter at which the cumulative frequency from the small particle diameter side becomes 90% is defined as D of silica particles. 90 It was decided.

[0152] <BET specific surface area SA of silica particles> The BET specific surface area SA of the silica particles was measured using a fully automatic specific surface area measuring device (Macsorb (registered trademark) HM model-1201) manufactured by Mountech Co., Ltd.

[0153] <Theoretical specific surface area SA' of silica particles> The theoretical specific surface area SA' of silica particles is calculated by the above-measured D 50 The values ​​were used to calculate the following formula (1).

[0154]

number

[0155] In the above formula (1), ρ is the density of the silica particles, and as shown in Tables 1 and 2, it is 1.80 g / cm 3 or 2.20 g / cm 3 The value of was used.

[0156] From the SA and SA' obtained above, the irregularity N was calculated according to the formula: irregularity N=SA / SA'.

[0157] <Evaluation of polishing removal rate and scratches> The episulfide resin substrate described below was prepared as the object to be polished, and (a) rough polishing, (b) medium polishing, and (c) fine polishing were performed in this order. (a) Rough polishing and (b) medium polishing were performed using the polishing compositions described in the respective steps below under the polishing conditions described in the respective steps below. In Tables 1 and 2 below, when "no" is written as medium polishing, this means that (b) medium polishing was omitted, and (a) rough polishing was followed by (c) fine polishing. GBIR and scratches on the object to be polished were evaluated according to the criteria described below.

[0158] [(a) Rough polishing] (a1) Polishing object: Episulfide resin substrate: 75mm diameter circular substrate, 0.550mm thick Flatness (thickness unevenness)…GBIR: Less than 0.5 μm Surface condition: Numerous lapping marks (depth 100-1,500 nm) (a2) Polishing composition: Abrasive grain (alumina grain, particle diameter D 50 A polishing composition (pH 3.2) containing 12.5 mass % of scouring powder (0.7 μm), 10 mass % of aluminum nitrate, and 0.5 mass % of PVP (water: the balance when the composition is taken as 100 mass %) was used.

[0159] (a3) Polishing conditions: Polishing equipment: Double-sided polishing machine 6BN (Hamai Sangyo Co., Ltd.) Surface plate diameter: 380 mm Polishing pad: Polyurethane pad (Shore D43.0, Shore A95) (Fujibo Ehime Co., Ltd., product name TYN13MP) Lower surface plate rotation speed: 45rpm Upper surface plate rotation speed: 0 rpm Internal gear: 60% Sun gear (forward): 150% Grinding pressure: 3.3psi Polishing composition flow rate (slurry flow rate): 10 mL / min Polishing time: 10 minutes.

[0160] [(b) Middle polishing] (b1) Polishing object: Polishing object after rough polishing (episulfide-based resin substrate) obtained through the above (a) rough polishing: circular substrate with a diameter of 75 mm and a thickness of 0.502 mm Flatness (thickness unevenness)…GBIR: Less than 0.5 μm ·Surface condition...Scratch: C.

[0161] (b2) Polishing composition: Abrasive grain (colloidal silica, particle size D 50 A polishing composition (pH 3.2) containing 15 mass % of (Ag: 187 nm), 8 mass % of aluminum nitrate, and 0.1 mass % of PVP (water: the balance when the composition is taken as 100 mass %) was used.

[0162] (b3) Polishing conditions: Polishing equipment: Double-sided polishing machine 6BN (Hamai Sangyo Co., Ltd.) Surface plate diameter: 380 mm Polishing pad: Polyurethane pad (Shore D43.0, Shore A95) (Fujibo Ehime Co., Ltd., product name TYN13MP) Lower surface plate rotation speed: 45rpm Upper surface plate rotation speed: 0 rpm Internal gear: 60% Sun gear (forward): 150% Grinding pressure: 2.9psi Polishing composition flow rate (slurry flow rate): 10 mL / min Grinding time: 5 minutes.

[0163] [(c) Fine Polishing] (c1-1) Polishing object: (b) Polishing object after middle polishing (episulfide-based resin substrate): 75 mm diameter circular substrate, 0.501 mm thick Flatness (thickness unevenness)…GBIR: Less than 0.5 μm ·Surface condition...Scratch: B.

[0164] (c1-2) Polishing composition: The polishing compositions used were those of Examples 1 to 17 and Comparative Examples 1 and 2. Details of each polishing composition are shown in Tables 1 and 2.

[0165] (c1-3) Polishing conditions: Polishing equipment: Double-sided polishing machine 6BN (Hamai Sangyo Co., Ltd.) Surface plate diameter: 380 mm Polishing pad: (a) Suede pad (Shore A73.0) (Fujibo Ehime Co., Ltd., product name K-1W-202U-SD) (b) Polyurethane pad (Shore D 43.0, Shore A 95) (manufactured by Fujibo Ehime Co., Ltd., product name TYN13MP) (in Tables 1 and 2, polyurethane is abbreviated as PU) (c) Nonwoven fabric pad (Shore A67.0) (SUBA800 manufactured by Nitta DuPont Co., Ltd.) Lower surface plate rotation speed: 45rpm Upper surface plate rotation speed: 0 rpm Internal gear: 60% Sun gear (forward): 150% Grinding pressure: 2.9psi Polishing composition flow rate (slurry flow rate): 5 mL / min, 10 mL / min, or 25 mL / min Grinding time: 5 minutes.

[0166] (c2-1) Polishing object: Polishing object after rough polishing (episulfide-based resin substrate) obtained through the above (a) rough polishing: circular substrate with a diameter of 75 mm and a thickness of 0.502 mm Flatness (thickness unevenness)…GBIR: Less than 0.5 μm Surface condition: Scratch: C.

[0167] (c2-2) Polishing composition: The polishing composition used was the polishing composition of Example 9 obtained above. Details of the polishing composition are shown in Table 2.

[0168] (c2-3) Polishing conditions: Polishing equipment: Double-sided polishing machine 6BN (Hamai Sangyo Co., Ltd.) Surface plate diameter: 380 [mm] Polishing pad: Suede pad (Shore A73.0) (Fujibo Ehime Co., Ltd. Product name K-1B-041U) Lower surface plate rotation speed: 45rpm Upper surface plate rotation speed: 0 rpm Internal gear: 60% Sun gear (forward): 150% Grinding pressure: 2.9psi Polishing composition flow rate (slurry flow rate): 10 mL / min Polishing time: 10 minutes.

[0169] Evaluation Method After the above (c) fine polishing, the polishing removal rate of the object to be polished (episulfide-based resin substrate) after fine polishing was evaluated according to the polishing removal rate evaluation method described below. In addition, scratches on the surface of the object to be polished (episulfide-based resin substrate surface) after polishing were evaluated according to the scratch evaluation method described below.

[0170] (Polishing removal rate evaluation method) 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: calculated as resin specific gravity 1.41) 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 s of the polishing surface of the object to be polished [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 converted to nm / min. This value was used as the polishing removal rate v (nm / min).

[0171] (Scratch evaluation method) Fine polishing was performed under the above conditions, and the surface condition of the object to be polished (episulfide-based resin substrate) after fine polishing was measured and evaluated for scratches according to the following evaluation criteria. If the evaluation was A or B, the product was usable. Here, scratches were defined as flaws with a depth of less than 100 nm measured using an AFM (atomic force microscope) (AFM Park NX-HDM, manufactured by Park Systems). Evaluation criteria; A: Under halogen light, there are no scratches or one scratch is visible; B: Under a halogen light source, 2 to 9 scratches are visible; C: More than 10 scratches can be seen under a halogen light source.

[0172] (Method for evaluating thickness unevenness (GBIR)) Using a NIDEK Corporation "Flatness Tester FT-900" flatness measurement device, GBIR (edge ​​exclusion region 5 mm) was measured in accordance with SEMI standards. The obtained measurements were evaluated on the following 7-point scale. The smaller the GBIR value, the flatter the surface and the less thickness unevenness. Evaluation criteria; <0.5: Less than 0.5 μm 0.5~1: 0.5μm or more and 1.0μm or less 1<<1.5: Over 1.0 μm and less than 1.5 μm 1.5~2: 1.5μm or more and 2.0μm or less 2<<2.5: Over 2.0 μm and less than 2.5 μm 2.5~3: 2.5μm or more and 3.0μm or less >3: More than 3.0μm.

[0173] (Root mean square height (Rms) evaluation method) In accordance with JIS B 0601:2013, non-contact 3D surface shape measurement was performed using a white light interferometer with a Zygo NewView9000 (manufactured by Ametech Co., Ltd.) to measure the root mean square height (Rms). The smaller the root mean square height (Rms) value, the smoother the surface.

[0174] As described above, the fine polishing process was carried out using each of the polishing compositions of Examples 1 to 17 and Comparative Examples 1 and 2. As a result, the thickness of the object to be polished after fine polishing with each polishing composition was within the range of 0.497 mm or more and 0.500 mm or less. The evaluation results of the polishing removal rate, GBIR, and scratches are shown in Tables 1 and 2 below.

[0175] [Table 1]

[0176] [Table 2]

[0177] As is clear from Tables 1 and 2 above, the polishing compositions of Examples were shown to be excellent in the effect of improving the polishing removal rate of the object to be polished (episulfide-based resin substrate) and in the effect of reducing thickness unevenness of the object to be polished (episulfide-based resin substrate) after polishing. On the other hand, the polishing compositions of Comparative Examples were shown to be inferior to Examples in at least one of the polishing removal rate of the object to be polished (episulfide-based resin substrate) and thickness unevenness of the object to be polished (episulfide-based resin substrate) after polishing. In addition, alumina particles (content 12.5% ​​by mass, average primary particle diameter D 50In the polishing composition of the comparative example (containing 8% by mass of aluminum sulfate and 0.1% by mass of PVP as polishing accelerators, pH 6.8; not listed in Tables 1 and 2 above) using a polishing accelerator (0.7 μm), polishing was carried out under the same polishing conditions as in Example 7, but defects with a scratch depth of 100 nm or more remained when observed by AFM, and the finished surface quality in the polishing process was not satisfactory.

Claims

1. A polishing composition used for polishing an object to be polished containing a resin material, Contains silica particles and water, The silica particles have an average particle diameter D ５０ The polishing composition has a particle size of 50 nm or more.

2. Further containing an abrasion accelerator, 2. The polishing composition according to claim 1, wherein the polishing accelerator is at least one selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound.

3. In the silica particles, the particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 50% is defined as D ５０ The BET specific surface area is SA, and the D ５０ 3. The polishing composition according to claim 1, wherein the irregularity N, expressed as N=SA / SA', is 1.2 or more, where SA' is the theoretical specific surface area calculated from the above formula.

4. The silica particles have an average particle diameter D ５０ The polishing composition according to claim 1 or 2, wherein the average particle size is 50 nm or more and less than 200 nm.

5. 3. The polishing composition according to claim 2, wherein the polishing accelerator comprises an aluminum salt of the monovalent acid and the pyrrolidone compound.

6. The silica particles are defined as a particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution of the silica particles is 10%. １０ The particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution of the silica particles is 90% is defined as D ９０ When this is done, D １０ D against ９０ The ratio (D ９０ / D １０ 3. The polishing composition according to claim 1, wherein the value of σ is 2.0 or more.

7. 3. The polishing composition according to claim 1, wherein the resin material is an optical resin material.

8. 3. The polishing composition according to claim 1, wherein the object to be polished has an average thickness of 1 mm or less before polishing.

9. 3. The polishing composition according to claim 1, wherein the polished object has a flatness defined by GBIR of 1.5 μm or less.

10. A polishing composition used for polishing an object to be polished containing a resin material, Contains silica particles, an abrasive accelerator, and water, the polishing accelerator is at least one selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound; The silica particles are defined as a particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution of the silica particles is 50%. ５０ The BET specific surface area is SA, and the D ５０ The polishing composition has an irregularity N of 1.5 or more, expressed by N=SA / SA', where SA' is the theoretical specific surface area calculated from the above formula.

11. A polishing method comprising the step of polishing an object containing a resin material with the polishing composition according to claim 1 .

12. A method for manufacturing an optical member, comprising a step of polishing an optical resin material by the polishing method according to claim 11.

13. a polishing composition is supplied between an object to be polished, which includes a resin material, and a polishing pad, and the object to be polished is polished; The polishing composition contains silica particles and water, The silica particles have an average particle diameter D ５０ is 50 nm or more.

14. 14. The polishing method according to claim 13, wherein the polishing pad has a Shore A hardness of 40 or more.

15. The polishing composition further contains a polishing accelerator, 15. The polishing method according to claim 13, wherein the polishing accelerator is at least one selected from the group consisting of an aluminum salt of a monovalent acid, a pyrrolidone compound, and a caprolactam compound.

16. In the silica particles, the particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 50% is defined as D ５０ The BET specific surface area is SA, and the D ５０ 15. The polishing method according to claim 13, wherein the irregularity N, expressed by N=SA / SA', is 1.2 or more, where SA' is the theoretical specific surface area calculated from the above formula.

17. The silica particles have an average particle diameter D ５０ The polishing method according to claim 13 or 14, wherein the average particle diameter is 50 nm or more and less than 200 nm.

18. 15. The polishing method according to claim 13, wherein the flatness of the object after polishing, as defined by GBIR, is 1.5 μm or less.

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