Polishing pad manufacturing method and polishing pad

Abstract

To provide a method for manufacturing a polishing pad which can stably maintain surface quality of a polished object obtained by polishing.SOLUTION: A method for manufacturing a polishing pad includes the steps of: preparing composite particles from a precursor composition containing polishing fine particles and matrix particles; depositing a curable composition containing a resin and the composite particles onto a base material; and curing the deposited curable composition and obtaining a polishing part, wherein a ratio D50Ma / D50Ab of a 50% cumulative volume particle diameter D50Ma of the matrix particles to a 50% cumulative volume particle diameter D50Ab of the polishing fine particles is 0.50 to 1.1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a polishing pad and a polishing pad. [Background technology]

[0002] High smoothness and minimal micro-defects are required for the surfaces of various glass materials, such as glass substrates used as the base material for magnetic disks in hard disk drives and reflective masks used in EUV lithography, as well as glass substrates used as the base material for LCD panels and cover glasses in mobile devices such as smartphones and tablets. Polishing pads with fixed abrasive grains are generally used for the surface grinding of such glass materials. Various techniques have also been proposed for agglomerating abrasive particles with matrix grains to form composite particles.

[0003] For example, Patent Document 1 discloses a polishing pad containing diamond bead abrasive particles (composite particles) in which diamond particles are held in a matrix of SiO2 (metal oxide) derived from colloidal silica. According to Patent Document 1, the use of such composite particles improves the polishing rate. Patent Document 2 discloses a polishing pad containing diamond aggregates (composite particles) in which diamond particles are held in a glass frit matrix. According to Patent Document 2, the use of such composite particles improves the polishing rate as well as the surface smoothness (surface roughness). Patent Document 3 discloses a method for producing composite particles with a glass frit matrix by a spray drying method. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2002-542057 [Patent Document 2] Special Publication No. 2003-534137 [Patent Document 3] Special Publication No. 2004-514017 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors have examined conventional polishing pads containing composite particles such as those described in Patent Documents 1 to 3 and found that the surface quality of the polished object obtained by polishing may not be sufficiently stable over time.

[0006] The present invention has been made in view of the above problems, and has as its object to provide a polishing pad capable of stably maintaining the surface quality of an object to be polished by polishing, and a method for manufacturing the same. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems. As a result, the present inventors have concluded that in a polishing pad containing composite particles, it is important not only to uniformly disperse the composite particles throughout the polishing pad, but also to uniformly disperse the abrasive particles within the matrix within the composite particles. They have then discovered that a polishing pad having a predetermined abrasive portion, which includes composite particles made using abrasive particles and matrix particles having a predetermined particle size ratio, can stably maintain the surface quality of the polished object obtained by polishing, and have completed the present invention.

[0008] That is, the present invention is as follows. [1] forming composite particles from a precursor composition comprising abrasive particulates and matrix particles; depositing a curable composition comprising a resin and the composite particles onto a substrate; and a step of curing the adhered curable composition to obtain a polished portion, 50% cumulative volume particle diameter D50 of the abrasive particles Ab and the 50% cumulative volume particle diameter D50 of the matrix particlesMa Compared to D50 Ma / D50 Ab is 0.50 to 1.1, A method for manufacturing a polishing pad. [2] In the particle size distribution of the matrix particles, 10% cumulative volume particle size D10 Ma , 90% cumulative volume particle size D90 Ma and the 50% cumulative volume particle size D50 Ma satisfies the following formula (1): [1] A method for producing a polishing pad according to the present invention. Formula (1): 1.0≦(D90 Ma -D10 Ma ) / D50 Ma ≦2.0 [3] In the particle size distribution of the matrix particles, 10% cumulative volume particle size D10 Ma , 90% cumulative volume particle size D90 Ma and the 50% cumulative volume particle size D50 Ma satisfies the following formula (2): [1] or [2], a method for producing a polishing pad. Formula (2): 0.35≦(D50 Ma -D10 Ma ) / (D90 Ma -D10 Ma )≦0.50 [4] the ratio of the amount of the abrasive particles to the amount of the matrix particles in the precursor composition is 0.25 to 2.0 by mass; The method for producing a polishing pad according to any one of [1] to [3]. [5] 50% cumulative volume particle diameter D50 of the matrix particles Ma is 1.0 to 30 μm, The method for producing a polishing pad according to any one of [1] to [4]. [6] 50% cumulative volume particle diameter D50 of the abrasive particles Ab is 1.0 to 30 μm, The method for producing a polishing pad according to any one of [1] to [5]. [7] the blending amount of the composite particles in the curable composition is 1.5 to 20 parts by mass with respect to 100 parts by mass of the curable composition; The method for producing a polishing pad according to any one of [1] to [6]. [8] the matrix particles include glass frit; The method for producing a polishing pad according to any one of [1] to [7]. [9] the abrasive particles contain at least one selected from the group consisting of diamond, cerium oxide, silicon carbide, silicon oxide, zirconium oxide, iron oxide, manganese oxide, magnesium oxide, zinc oxide, titanium oxide, aluminum oxide, zirconium silicate, boron nitride, silicon nitride, barium sulfate, and calcium carbonate; The method for producing a polishing pad according to any one of [1] to [8].

[10] The curable composition further contains a filler having a 50% cumulative volume particle size of 5.0 to 30 μm. The method for producing a polishing pad according to any one of [1] to [9].

[11] The curable composition further contains auxiliary particles having a 50% cumulative volume particle size of 0.5 to 4.5 μm. The method for producing a polishing pad according to any one of [1] to

[10] .

[12] A substrate and an abrasive portion disposed on the substrate, the abrasive portion includes a resin and composite particles; the composite particles are made from a precursor composition comprising abrasive particulates and matrix particles; 50% cumulative volume particle diameter D50 of the abrasive particles Ab and the 50% cumulative volume particle diameter D50 of the matrix particles Ma Compared to D50 Ma / D50 Ab is 0.50 to 1.1, Polishing pad.

[13] A polishing pad manufactured by the method for manufacturing a polishing pad according to any one of [1] to

[11] . [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a method for manufacturing a polishing pad and a polishing pad that can stably maintain the surface quality of an object to be polished by polishing. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing a polishing pad according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing the polishing pad of the present embodiment. [Figure 3] FIG. 2 is a graph showing the volume-based particle size distribution of glass frit, which is the matrix particle used in the examples. [Figure 4] 1 is an electron microscope photograph of composite particles in the polishing pad of Example 1. [Figure 5] 1 is an electron microscope photograph of composite particles in the polishing pad of Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] Below, we will explain in detail the embodiment of the present invention (hereinafter referred to as the ``present embodiment''), but the present invention is not limited to this and various modifications are possible within the scope of the gist of the present invention.

[0012] 1. Polishing pad The polishing pad of this embodiment includes a substrate and an abrasive portion disposed on the substrate. The abrasive portion includes a resin and composite particles. The composite particles are made from a precursor composition including abrasive particles and matrix particles. The 50% cumulative volume particle diameter D50 of the abrasive particles is Ab and 50% cumulative volume particle diameter D50 of the matrix particles Ma Compared to D50 Ma / D50 Ab However, it is 0.50 to 1.1.

[0013] A schematic perspective view of a polishing pad according to this embodiment is shown in Figure 1. As shown in Figure 1, this polishing pad 10 includes a substrate 12 and a polishing portion 11 disposed on the substrate 12. In Figure 1, a plurality of convex portions formed by the polishing portion 11 are disposed on the surface of the substrate 12, forming an uneven pattern.

[0014] The polishing portion 11 may form a concave-convex pattern together with the substrate 12 as shown in Fig. 1, or may be a uniform layer formed on the surface of the substrate. The concave-convex pattern may be a pattern (negative pattern) formed by the polishing portion 11 formed by punching out dots from a uniform layer, in addition to a concave-convex pattern formed by arranging convex portions, or any other pattern.

[0015] FIG. 2 shows a schematic cross-sectional view of a polishing pad according to this embodiment. As shown in FIG. 2, the polishing portion 11 of the polishing pad 10 contains composite particles 14 in a resin 15. As polishing progresses, the polishing surface of the polishing portion 11 is gradually worn away, exposing the composite particles 14 embedded in the polishing portion 11 and forming a new polishing surface. Because the composite particles 14 are made using abrasive microparticles and matrix particles with a predetermined particle size ratio, the surface quality of the polished object obtained by polishing is improved over time, as described below. The polishing portion 11 may contain fillers and / or auxiliary particles. Each component of the polishing pad of this embodiment will be described in detail below.

[0016] 1.1. Base material The substrate is not particularly limited, but examples thereof include polyester films such as polyethylene terephthalate film, polypropylene terephthalate film, and polybutylene terephthalate film; polyolefin films such as polyethylene (PE) film, polypropylene (PP) film, and ethylene-propylene copolymer film; polyether ether ketone (PEEK) film, and polyphenylene sulfide (PPS) film.

[0017] The substrate is not particularly limited as long as it is possible to form a resin on the upper surface thereof, as described below. Among these, polyester films are preferred from the viewpoints of chemical resistance, heat resistance, cost efficiency, etc.

[0018] 1.2. Polishing section The abrasive portion contains a resin and composite particles, and may contain fillers and / or auxiliary particles as needed. The abrasive portion may be formed as a uniform layer on the surface of the substrate, or may be formed alone or together with the substrate to form a concave-convex pattern (see Figures 1 and 2).

[0019] Among these, it is preferable that the polishing part has a regular uneven pattern from the viewpoint of supplying or discharging liquid components used during polishing, such as slurry, to the polishing surface. Having a regular pattern enables uniform polishing, and polishing of the polished object with excellent surface quality can be achieved. Note that a "regular pattern" refers to a pattern obtained by arranging multiple small unit patterns. Furthermore, the surface of the polishing part opposite the substrate serves as the polishing surface for polishing the object to be polished.

[0020] The concave-convex pattern is not particularly limited as long as it has portions that contact the workpiece (convex portions) and portions that do not contact the workpiece (concave portions). Examples include a positive pattern (a pattern with dot-shaped convex portions) in which the abrasive portions 11 are independently formed on the substrate 12 as shown in FIG. 1; a negative pattern (a pattern with dot-shaped concave portions) in which the abrasive portions are continuously formed on the substrate; a pattern with donut-shaped convex portions; a pattern with approximately C-shaped convex portions; a pattern with concentric circular portions that contact the workpiece and portions that do not contact the workpiece; a grid-shaped pattern with portions that contact the workpiece and portions that do not contact the workpiece; a radial pattern with portions that contact the workpiece and portions that do not contact the workpiece; a spiral pattern with portions that contact the workpiece and portions that do not contact the workpiece; or a pattern formed by combining these. Among these, a pattern with dot-shaped convex portions is preferred. Having such a concave-convex pattern tends to further improve the discharge of polishing debris.

[0021] The three-dimensional shape of the dots in a pattern having dot-shaped protrusions is not particularly limited, and examples thereof include hemispherical, approximately hemispherical, spherical cap, approximately spherical cap, spherical band, approximately spherical band, semi-ellipsoidal, approximately semi-ellipsoidal, columnar (cylindrical, approximately cylindrical, elliptical cylinder, approximately elliptical cylinder, polygonal columnar), and frustum (circular truncated cone, approximately circular truncated cone, elliptical truncated cone, approximately elliptical truncated cone, polygonal truncated cone). The frustum may be a frustum that expands from the substrate side toward the polishing surface side, or a frustum that expands from the polishing surface side toward the substrate side. In addition, the three-dimensional shape of the space in the recesses in a pattern having dot-shaped recesses can be similar to the three-dimensional shape in a pattern having dot-shaped protrusions.

[0022] Resin The resin is not particularly limited, but thermoplastic resins and photocurable resins are preferred, and examples thereof include polyurethane-based resins such as polyurethanes having an ether or ester bond in the molecule and polyurethane polyureas; acrylic resins such as monofunctional acrylates, difunctional acrylates, polyfunctional acrylates, polyester acrylates, polyurethane acrylates, epoxy acrylates, acrylic phenolic resins, and polyacrylonitrile; vinyl resins such as polyvinyl chloride, polyvinyl acetate, and polyvinylidene fluoride; polysulfone-based resins such as polysulfone and polyethersulfone; cellulose-based resins such as acetylated cellulose and butyrylated cellulose; polyamide-based resins; and polystyrene-based resins, unsaturated polyester resins, phenolic resins, urea resins, melamine resins, polyimide resins, alkyd resins, and phenol-modified alkyd resins.

[0023] Among these, acrylic resins, polyurethane resins, unsaturated polyester resins, and phenolic alkyd resins are preferred. By using such resins, the polishing rate tends to be further improved. The resins constituting the polishing part may be used alone or in combination of two or more.

[0024] 1.2.2. Composite particles The composite particles are made from a precursor composition containing abrasive particles and matrix particles. That is, the composite particles of this embodiment are particles in which a plurality of abrasive particles and a plurality of matrix particles are aggregated, and the matrix particles are further fused together. The composite particles are particles containing a matrix formed by a plurality of fused matrix particles and abrasive particles dispersed in the matrix. Here, the abrasive particles are components that contribute to polishing, and the matrix functions as a binder for the abrasive particles.

[0025] Regarding the abrasive particles and matrix particles used in producing the composite particles 14, the 50% cumulative volume particle diameter D50 of the abrasive particles Ab and 50% cumulative volume particle diameter D50 of the matrix particles Ma Compared to D50 Ma / D50 Ab is 0.50 to 1.1. The present inventors have found that when composite particles are prepared using abrasive particles and matrix particles whose particle size ratio is specified as above, the surface quality of the polished object obtained by polishing can be stably maintained. The reasons for this are not necessarily limited to the following, but the present inventors speculate that when the ratio of the 50% cumulative volume particle sizes of the abrasive particles and the matrix particles is within the above range, the two types of particles become more compatible with each other due to their similar particle sizes, increasing their affinity, and therefore the abrasive particles are not only uniformly dispersed in the composite particles but also properly retained within the composite particles.

[0026] That is, the ratio D50 Ma / D50 Ab If the value is smaller than the above range and the matrix particles are extremely small compared to the abrasive particles, the abrasive particles will be embedded in the matrix, preventing the abrasive particles from functioning properly, resulting in unstable polishing performance. Furthermore, in the composite particle preparation step described below, the viscosity of the precursor composition used in the precursor particle preparation step will increase, which may result in poor dispersibility of the abrasive particles.

[0027] Also, the ratio D50 Ma / D50 Abis a value larger than the above range and the matrix particles are extremely large compared to the abrasive particles, the abrasive particles will not be sufficiently dispersed within the matrix, the abrasive particles will not come into uniform contact with the workpiece to be polished, and the ability of the matrix to hold the abrasive particles will decrease, making the abrasive particles more likely to fall off, resulting in unstable polishing performance.

[0028] From the same viewpoint, the above ratio D50 Ma / D50 Ab is preferably 0.55 to 1.0, more preferably 0.60 to 0.95, and even more preferably 0.65 to 0.90.

[0029] In this embodiment, the 50% cumulative volume particle size refers to the particle size (μm) when the cumulative value from the smallest diameter reaches 50% of the total in the cumulative distribution of particle sizes on a volume basis. In this embodiment, values ​​related to particle sizes, including the 50% cumulative volume particle size, can be measured using a laser diffraction particle size distribution analyzer described in the Examples.

[0030] In the preparation of the composite particles, the above ratio D50 Ma / D50 Ab The use of abrasive particles and matrix particles with a ρ of 0.50 to 1.1 can be estimated, for example, by checking that the compressive fracture strength (described later) is within a predetermined range, or by observing the cross section of the composite particles with an electron microscope. However, during the preparation of the composite particles, the abrasive particles and matrix particles are heated at high temperatures, causing the matrix particles to fuse together. Therefore, it is not easy to determine the particle size of the matrix particles used as raw materials simply by observing the composite particles.

[0031] The 50% cumulative volume particle diameter D50 of the composite particles is preferably 5 to 100 μm, more preferably 10 to 80 μm, and even more preferably 15 to 60 μm. When the 50% cumulative volume particle diameter D50 is within the above range, the grinding force is excellent and the surface quality of the polished object obtained by polishing tends to be improved.

[0032] The volumetric particle size of the particles contained in the polishing section may be measured, for example, by removing the particles to be measured from the polishing section and using a laser diffraction particle size distribution analyzer described in the Examples. Methods for removing the particles to be measured from the polishing section include, for example, heating the polishing pad to about 550°C, ashing the sample, extracting the particles from the polishing pad, and thoroughly dispersing them using an ultrasonic disperser or the like to prepare a dispersion. Using this dispersion, the cumulative volumetric particle size of the particles can be determined from the particle size distribution measured using a laser diffraction scattering particle size distribution analyzer. Alternatively, the particle size and number of particles exposed on the surface of the polishing section can be measured using SEM images, etc., and the cumulative volumetric particle size of the particles can be determined from the particle size distribution obtained by converting the particle size and particle size distribution into volume.

[0033] The content of the composite particles is preferably 1.5 to 20 parts by mass, more preferably 2.5 to 15 parts by mass, and even more preferably 5.0 to 10 parts by mass, per 100 parts by mass of the abrasive part. When the content of the composite particles is 1.5 parts by mass or more, the grinding force tends to be further improved. Furthermore, when the content of the composite particles is 20 parts by mass or less, the polishing pressure applied to the composite particles increases, and the polishing rate tends to be further improved. Furthermore, when the content of the composite particles is within the above range, the load on each composite particle and each abrasive fine particle contained in the composite particle is appropriately distributed, and therefore the stability over time of the surface quality of the polished object obtained by polishing tends to be further improved.

[0034] The compressive fracture strength (crushing strength) of the composite particles according to the Japanese Industrial Standard (JIS R 1639-5:2007) is preferably 50 MPa or more, more preferably 80 MPa or more, even more preferably 100 MPa or more, and even more preferably 120 MPa or more. When the compressive fracture strength is within the above range, the retention force of the abrasive particles in the composite particles is improved, and the abrasive particles are prevented from falling off the composite particles. This makes it possible to control the location of the abrasive particles, making it easier to achieve a more uniform distribution of the abrasive particles on the polishing surface, which tends to further improve the stability over time of the surface quality of the polished object obtained by polishing.

[0035] The upper limit of the compressive fracture strength of the composite particles is not particularly limited, but may be, for example, 500 MPa, 400 MPa, 300 MPa, or 200 MPa. The specific method for measuring the compressive fracture strength may be the method described in the Examples.

[0036] 1.2.2.1. Abrasive particles The abrasive particles are components that contribute to polishing, and when the composite particles contain the abrasive particles, the polishing performance of the polishing portion becomes favorable.

[0037] The components constituting the abrasive particles are not particularly limited, but are preferably the hardest material in the polishing pad and the component with the highest grinding ability. For example, at least one selected from the group consisting of diamond, cerium oxide, silicon carbide, silicon oxide, zirconium oxide, iron oxide, manganese oxide, magnesium oxide, zinc oxide, titanium oxide, aluminum oxide, zirconium silicate, boron nitride, silicon nitride, barium sulfate, and calcium carbonate may be used. These abrasive particles may be used alone or in combination of two or more.

[0038] The content of the abrasive particles is preferably 5.0 to 50 parts by mass, more preferably 10 to 45 parts by mass, and even more preferably 15 to 40 parts by mass, relative to 100 parts by mass of the composite particles. When the content of the abrasive particles is within the above range, the number of contact points between the abrasive particles and the workpiece to be polished is appropriately increased, and the load on each abrasive particle is appropriately distributed, so that the polishing rate can be maintained more stably and the surface roughness of the workpiece obtained by polishing tends to be further reduced.

[0039] Matrix The matrix is ​​formed by fusing together a plurality of matrix particles. The matrix functions as a binder for the abrasive particles and is a component that does not contribute much to polishing. By forming the matrix of the composite particle from matrix particles with the particle size ratio controlled as described above, the abrasive particles are held within the composite particle, and the composite particle disintegrates when pressed against the workpiece with a certain amount of stress.

[0040] The components constituting the matrix are not particularly limited, but examples include glasses such as silicate glass, borosilicate glass, phosphate glass, and bismuth-based glass, with borosilicate glass being preferred. Constituent components of borosilicate glass include silicon dioxide (silica), boron oxide, aluminum oxide, magnesium oxide, zinc oxide, calcium oxide, lithium oxide, sodium oxide, and potassium oxide. Among these, it is preferable to include silicon dioxide (silica), aluminum oxide, boron oxide, sodium oxide, and calcium oxide, or silicon dioxide, boron oxide, sodium oxide, calcium oxide, and zinc oxide. These matrix components may be used alone or in combination of two or more.

[0041] The matrix content is preferably 50 to 95 parts by mass, more preferably 55 to 90 parts by mass, and even more preferably 60 to 85 parts by mass per 100 parts by mass of composite particles. When the matrix content is 50 parts by mass or more, the spacing between the abrasive particles is appropriately increased, reducing the contact points between the abrasive particles and the workpiece during polishing, resulting in an appropriate load being applied to each abrasive particle, and tending to further improve the grinding force. When the matrix content is 95 parts by mass or less, the load applied to each abrasive particle is appropriately distributed, allowing for a more stable polishing rate to be maintained, and the surface roughness of the polished object obtained by polishing tends to be reduced.

[0042] 1.2.3. Filler (first filler) The polishing part 11 may further contain a filler in addition to the resin and the composite particles. When the polishing part contains a filler, the filler is released from the polishing part, thereby controlling the release of the composite particles, and self-dressing properties are more likely to be exhibited, which tends to further improve the stability of the polishing rate over time. The 50% cumulative volume particle size of such a filler may be 5.0 to 30 μm.

[0043] The filler is not particularly limited as long as it is a component that is relatively ineffective in polishing, and examples thereof include inorganic particles with a Mohs hardness lower than that of the abrasive particles. The shape of the inorganic particles is not particularly limited, and examples thereof include whisker-like, columnar, flaky, and scaly shapes. Furthermore, the components constituting such inorganic particles are not particularly limited, and examples thereof include silicate minerals such as potassium aluminum silicate (Mohs hardness 6), diatomaceous earth (Mohs hardness 6-7), and wollastonite (Mohs hardness 4.5-5); metal oxides such as iron oxide (Mohs hardness 6), titanium oxide (Mohs hardness 6.5), zinc oxide (Mohs hardness 4), and aluminum oxide (Mohs hardness 9); metal carbonates such as calcium carbonate (Mohs hardness 3) and magnesium carbonate (Mohs hardness 3.5); and metal sulfates such as calcium sulfate (Mohs hardness 3.5) and barium sulfate (Mohs hardness 3-3.5). Among these, from the viewpoint of achieving a suitable range of fixing force and self-dressing property of the composite particles, a filler having shape anisotropy is preferred, specifically wollastonite. When the filler has shape anisotropy, the length in the major axis direction relative to the length in the minor axis direction (aspect ratio) is preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more. The upper limit of the aspect ratio is not particularly limited, and is, for example, 12, 10, or 7.

[0044] Wollastonite is a silicate mineral containing calcium silicate (CaSiO3) and is also known as wollastonite. In addition to calcium, wollastonite may also contain silicates of other metals, such as iron, manganese, sodium, and lithium. By including such a filler in the polishing part, the polishing rate can be maintained stably, and the surface roughness of the resulting polished object tends to be reduced.

[0045] The 50% cumulative volume particle size of the filler is preferably 5.0 to 30 μm, more preferably 7.5 to 25 μm, and even more preferably 10 to 20 μm. If the 50% cumulative volume particle size of the filler is 30 μm or less, even when the shape-anisotropic filler is mixed with a resin in the polishing pad manufacturing method described below, excessive viscosity is suppressed, and the polishing pad tends to be easily molded. If the 50% cumulative volume particle size of the filler is 5.0 μm or more, the wear resistance of the polishing pad is improved and the self-dressing property falls within a suitable range.

[0046] The ratio of the 50% cumulative volume particle diameter of the composite particles to the 50% cumulative volume particle diameter of the filler is preferably 0.50 to 10, more preferably 1.0 to 8.0, and even more preferably 1.5 to 5.0. When the ratio is within the above range, the releasability of the filler falls within a suitable range, and the fixation property and grinding force of the composite particles tend to be further improved.

[0047] The content of the filler is preferably 40 to 70 parts by mass, more preferably 45 to 65 parts by mass, and even more preferably 50 to 60 parts by mass, relative to 100 parts by mass of the polishing part. When the content of the filler is within the above range, the polishing part tends to exhibit self-dressing properties, and new composite particles can continue to appear, which tends to stabilize the polishing rate and further reduce the surface roughness of the polished object.

[0048] The ratio of the filler content to the composite particle content is preferably 1.5 to 22.5, more preferably 2.5 to 17.5, and even more preferably 5.0 to 12.5. When the ratio of the filler content to the composite particle content is within the above range, the spacing between the composite particles becomes appropriate, the load on the composite particles is easily equalized, the polishing rate can be maintained more stably, and the surface roughness of the resulting polished object tends to be reduced.

[0049] 1.2.4. Auxiliary particles (secondary fillers) The auxiliary particles are not particularly limited, but examples thereof include inorganic particles having a 50% cumulative volume particle size of 0.5 to 4.5 μm. When the polishing part contains such auxiliary particles, the composite particles and filler tend to be more uniformly dispersed in the polishing part, and the surface quality of the polished object obtained by polishing tends to be more stable over time.

[0050] The components constituting such auxiliary particles are not particularly limited, but examples thereof include aluminum oxide, silicon carbide, barium sulfate, and cerium oxide. Among these, aluminum oxide is preferred, and white alumina is more preferred. By using such components as auxiliary particles, the polishing rate tends to improve, possibly because the auxiliary particles detached during self-dressing of the filler assist in self-dressing. These auxiliary particles may be used alone or in combination of two or more.

[0051] The 50% cumulative volume particle size of the auxiliary particles is, for example, 0.5 to 4.5 μm, preferably 0.7 to 4.0 μm, and more preferably 0.9 to 3.5 μm. When the 50% cumulative volume particle size of the auxiliary particles is within the above range, the effect of improving the polishing rate is easily obtained, and the surface roughness of the obtained polished object tends to be further reduced.

[0052] The content of the auxiliary particles is preferably 1.0 to 10 parts by mass, more preferably 1.5 to 7.5 parts by mass, and even more preferably 2.5 to 5.0 parts by mass, relative to 100 parts by mass of the polishing part. When the content of the auxiliary particles is within the above range, the effect of improving the polishing rate is easily obtained, and the surface roughness of the obtained polished object tends to be further reduced.

[0053] The ratio of the content of auxiliary particles to the content of composite particles is preferably 0.25 to 2.5, more preferably 0.30 to 1.5, and even more preferably 0.40 to 1.0. When the ratio of the content of auxiliary particles to the content of composite particles is within the above range, the effect of improving the polishing rate is easily obtained, and the surface roughness of the obtained polished object tends to be further reduced.

[0054] The auxiliary particles may be present in the polishing part so as to cover the surface of the composite particles, or may be dispersed or aggregated independently in the polishing part.

[0055] The filler in 1.2.3. above may be considered to include auxiliary particles, in which case the filler in 1.2.3. may be distinguished as the first filler and the auxiliary particles as the second filler. The first filler may be a shape-anisotropic filler, and the second filler may be a filler having a 50% cumulative volumetric particle size of 0.5 to 4.5 μm. Alternatively, the first filler may be a shape-anisotropic filler and a 50% cumulative volumetric particle size of 4.5 to 30 μm (or 5.0 to 30 μm), and the second filler may be a filler having a 50% cumulative volumetric particle size of 0.5 to 4.5 μm.

[0056] The auxiliary particles may be components that contribute to polishing. In this case, the auxiliary particles are particles with a lower grinding power than the abrasive particles (particles with a lower Mohs hardness and / or a smaller particle diameter). In other words, particles with a higher grinding power become the abrasive particles. For example, when diamond particles (Mohs hardness 10) are used as the abrasive particles, particles with a Mohs hardness of less than 10 can be used as the auxiliary particles, such as aluminum oxide (Mohs hardness 9). The aluminum oxide may have a 50% cumulative volumetric particle diameter of 0.5 to 4.5 μm.

[0057] 1.3.Adhesive layer The polishing pad of this embodiment may further include an adhesive layer on the opposite side of the substrate from the polishing portion for attaching the polishing pad to the polishing platen of a polishing machine. The adhesive layer may contain an adhesive or pressure-sensitive adhesive used in conventionally known polishing pads.

[0058] Examples of materials for the adhesive layer include various thermoplastic adhesives such as acrylic adhesives, nitrile adhesives, nitrile rubber adhesives, polyamide adhesives, polyurethane adhesives, polyester adhesives, silicone adhesives, etc. The adhesive layer may also be, for example, double-sided tape.

[0059] Anchor Layer The polishing pad of this embodiment may have an anchor layer between the substrate and the polishing part. By having an anchor layer, the adhesion between the substrate and the polishing part tends to be further improved.

[0060] The material for forming the anchor layer is not particularly limited, but may be, for example, a thermosetting resin coating agent.

[0061] The polishing pad of this embodiment has been described above with reference to the drawings as appropriate. The polishing pad has a substrate and an abrasive portion disposed on the substrate, the abrasive portion contains a resin and composite particles, the composite particles are made from a precursor composition containing abrasive particles and matrix particles, and the 50% cumulative volume particle diameter D50 of the abrasive particles is Ab and 50% cumulative volume particle diameter D50 of the matrix particles Ma Compared to D50 Ma / D50 Ab As long as the ratio is 0.50 to 1.1, the polishing pad of this embodiment is not limited to the above-described embodiments.

[0062] The polishing pad of this embodiment may be a polishing pad manufactured by the polishing pad manufacturing method of this embodiment described later. In such an embodiment, each component of the polishing pad can optionally adopt each component of the embodiment described in detail above.

[0063] 2. Manufacturing method of polishing pad The method for producing a polishing pad of this embodiment includes a step of preparing composite particles from a precursor composition containing abrasive particles and matrix particles (composite particle preparation step), a step of adhering a curable composition containing a resin and the composite particles onto a substrate (adhering step), and a step of curing the adhered curable composition to obtain a polishing portion (curing step), and the 50% cumulative volume diameter D50 of the abrasive particles is Ab and 50% cumulative volume particle diameter D50 of the matrix particles Ma Compared to D50 Ma / D50 Abis 0.50 to 1.1. The method for producing a polishing pad of this embodiment may include a step of forming the adhesive layer and / or anchor layer described above.

[0064] 2.1. Composite particle production process The composite particle preparation process is a process for preparing composite particles from a precursor composition containing abrasive particles and matrix particles. Ab and 50% cumulative volume particle diameter D50 of the matrix particles Ma Compared to D50 Ma / D50 Ab is 0.50 to 1.1. This step is not particularly limited as long as it can produce composite particles from a precursor composition containing abrasive particles and matrix particles, but it may include, for example, the following steps, and preferably includes at least a precursor particle production step and a firing step.

[0065] 2.1.1. Matrix particle sizing process The composite particle preparation step may include a first step of sizing the matrix particles by pulverizing them (matrix particle sizing step). In this step, commercially available matrix particles are pulverized to a size of 0.05 to 0.05 mm. Ma / D50 Ab This is a process of adjusting the particle size of the matrix particles so that the particle size falls within the above range.

[0066] The matrix particles are not particularly limited, but examples include glass frits such as silicate glass, borosilicate glass, phosphate glass, and bismuth-based glass. Borosilicate glass is preferred. Examples of borosilicate glass frits include silicon dioxide (silica), boron oxide, aluminum oxide, magnesium oxide, zinc oxide, calcium oxide, lithium oxide, sodium oxide, and potassium oxide. Among these, glass frits containing silicon dioxide (silica), aluminum oxide, boron oxide, sodium oxide, and calcium oxide, and glass frits containing silicon dioxide, boron oxide, sodium oxide, calcium oxide, and zinc oxide are preferred. The use of such matrix particles results in composite particles strong enough to hold abrasive particles without crushing the matrix particles during conditioning. This tends to maintain polishing performance more stably. These matrix particles may be used alone or in combination.

[0067] In this step, the matrix particles may be pulverized by, for example, a wet pulverization method using a ball mill. For example, the solvent may be water, and the ball mill may be made of alumina balls. The pulverization using the ball mill may be carried out at preferably 200 to 500 rpm, more preferably 300 to 450 rpm, for preferably 12 to 36 hours, more preferably 18 to 30 hours.

[0068] 2.1.2.Precursor particle production process The composite particle preparation process may include a step of preparing precursor particles from a precursor composition containing abrasive particles, matrix particles, and a binder resin (precursor particle preparation process), and a step of baking the precursor particles to prepare composite particles (baking process). The precursor composition does not need to contain a binder resin, but preferably does.

[0069] The precursor particle preparation step may be a step of preparing a precursor composition by mixing abrasive particles, arbitrarily sized matrix particles, a binder resin, and a solvent, and then granulating the precursor composition. The abrasive particles may have the structure described in detail in 1. Polishing Pad above, and the preferred embodiments are also the same.

[0070] In this process, the 50% cumulative volume particle diameter D50 of the abrasive particles used as raw material Ab and 50% cumulative volume particle diameter D50 of the matrix particles Ma Compared to D50 Ma / D50 Ab is 0.50 to 1.1.

[0071] 50% cumulative volume particle size D50 of abrasive particles Ab can be adjusted appropriately depending on the type of workpiece and the type of polishing process (primary lapping (rough lapping), secondary lapping (finish lapping), polishing, etc.). For example, in the case of primary lapping, the 50% cumulative volume particle diameter D50 Ab In the case of secondary lapping, the 50% cumulative volume particle diameter D50 Ab In the case of primary lapping, it is sufficient to use abrasive particles smaller than those in the case of polishing, and the 50% cumulative volume particle size D50 Ab The 50% cumulative volume diameter D50 of the abrasive particles can be calculated by using abrasive particles that are smaller than those used in the secondary lapping. Ab The 50% cumulative volume particle diameter D50 is preferably 1.0 to 30 μm, more preferably 1.5 to 10 μm, even more preferably 2.0 to 7.5 μm, and even more preferably 3.0 to 5.0 μm. Ab By keeping the above range, it is possible to prevent the grinding rate from decreasing significantly, leading to a decrease in grinding efficiency, and to prevent the abrasive particles from forming deep scratches on the workpiece, which would result in an excessive increase in the polishing load on the next process. It is presumed that the size of the abrasive particles used as raw material is roughly equivalent to the size of the abrasive particles in the composite particles contained in the polishing portion of the polishing pad.

[0072] 50% cumulative volume particle diameter of matrix particles D50Ma is D50 Ab and the above ratio D50 Ma / D50 Ab The 50% cumulative volume particle diameter D50 may be adjusted appropriately depending on the application, but is preferably 1.0 to 30 μm, more preferably 1.5 to 8.0 μm, more preferably 2.0 to 5.0 μm, and even more preferably 2.5 to 4.5 μm. Ma When the surface quality of the polished object obtained by polishing is within the above range, the stability over time of the surface quality tends to be further improved.

[0073] In the particle size distribution of matrix particles, 10% cumulative volume particle size D10 Ma , 90% cumulative volume particle size D90 Ma , and 50% cumulative volume particle size D50 Ma preferably satisfies the following formula (1). Formula (1): 1.0≦(D90 Ma -D10 Ma ) / D50 Ma ≦2.0

[0074] When the particle size distribution of the matrix particles satisfies the above formula (1), the particle size distribution of the matrix particles becomes appropriately dispersed. Ma There are no matrix particles with extremely different sizes (50% cumulative volume particle size D50 Ma Since there are many matrix particles with similar sizes, the matrix particles and abrasive particles tend to be dispersed uniformly. Ma -D10 Ma ) / D50 M is more preferably 1.2 to 1.9, and further preferably 1.4 to 1.8.

[0075] In the particle size distribution of matrix particles, 10% cumulative volume particle size D10 Ma , 90% cumulative volume particle size D90 Ma , and 50% cumulative volume particle size D50 Ma preferably satisfies the following formula (2). Formula (2): 0.35≦(D50 Ma -D10Ma ) / (D90 Ma -D10 Ma )≦0.50

[0076] When the particle size distribution of the matrix particles satisfies the above formula (2), the amount of small particles is greater than that of particles larger than the 50% cumulative volumetric particle size, and the small matrix particles tend to be densely packed between matrix particles and abrasive particles having particle sizes close to the 50% cumulative volumetric particle size. This tends to bring the holding power of the abrasive particles in the composite particles into a more suitable range. From the same perspective, the ratio (D50 Ma -D10 Ma ) / (D90 Ma -D10 Ma ) is more preferably 0.36 to 0.47, and even more preferably 0.37 to 0.45.

[0077] From the same viewpoint, the 10% cumulative volume diameter D10 of the matrix particles Ma is preferably 0.3 to 10 μm, more preferably 0.5 to 5.0 μm, and even more preferably 0.7 to 1.3 μm.

[0078] From the same viewpoint, the 90% cumulative volume diameter D90 of the matrix particles Ma is preferably 2.0 to 60 μm, more preferably 2.5 to 20 μm, and further preferably 3.0 to 10 μm.

[0079] In the precursor composition used to prepare the precursor particles, the ratio of the content of abrasive particles to the content of matrix particles is preferably 0.25 to 2.0 by mass, more preferably 0.30 to 1.0, and even more preferably 0.35 to 0.70. When the content ratio is within the above range, the dispersibility of the abrasive particles in the composite particles is improved, and the surface quality of the polished object obtained by polishing tends to be more stable over time.

[0080] The content of the abrasive particles is preferably 5.0 to 50 parts by mass, more preferably 10 to 45 parts by mass, and even more preferably 15 to 40 parts by mass, based on 100 parts by mass of the total components of the precursor composition excluding the binder resin and solvent. When the content of the abrasive particles is within the above range, the number of contact points between the abrasive particles and the workpiece to be polished is appropriately increased, and the load on each abrasive particle is appropriately distributed, so that the polishing rate can be maintained more stably and the surface roughness of the workpiece obtained by polishing tends to be further reduced.

[0081] The content of matrix particles is preferably 50 to 95 parts by weight, more preferably 55 to 90 parts by weight, and even more preferably 60 to 85 parts by weight, based on 100 parts by weight of the total components of the precursor composition excluding the binder resin and solvent. When the content of matrix particles is 50 parts by weight or more, the spacing between the abrasive particles is appropriately increased, reducing the contact points between the abrasive particles and the workpiece during polishing, resulting in an appropriate load per abrasive particle and tending to further improve grinding power. When the content of matrix particles is 95 parts by weight or less, the load on each abrasive particle is appropriately distributed, resulting in a more stable polishing rate and a tendency for the surface roughness of the polished object obtained by polishing to be reduced.

[0082] In this step, the precursor composition may be granulated, and then the precursor particles and auxiliary particles may be mixed. In this case, the auxiliary particles may be added so as to cover the surfaces of the precursor particles. The auxiliary particles may have the configuration and preferred embodiments detailed in 1. Polishing Pad above, and the compounding ratio may be adjusted so that the content ratio of each component is the content ratio detailed in 1. Polishing Pad above.

[0083] The binder resin is preferably a resin that can bind the abrasive particles and the matrix particles and can be thermally decomposed by the baking process described below. A water-soluble resin is more preferable, and a resin commonly used as a binder can be used. Examples of such a resin include dextrin, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, and polyacrylamide, with dextrin being preferred. These binder resins may be used alone or in combination of two or more.

[0084] The blending amount of the binder resin is preferably 3.0 to 50 parts by mass, more preferably 5.0 to 40 parts by mass, and even more preferably 10 to 30 parts by mass, per 100 parts by mass of the total of the abrasive particles and matrix particles.

[0085] Examples of the solvent include water and alcohols such as methanol and isopropanol, with water being preferred. These solvents may be used alone or in combination of two or more.

[0086] The blending amount of the solvent is preferably 20 to 150 parts by mass, more preferably 50 to 120 parts by mass, and even more preferably 60 to 100 parts by mass, per 100 parts by mass of the total of the abrasive particles and matrix particles.

[0087] In addition to the above components, the precursor composition may contain other additives. Examples of other additives include deflocculants (dispersants) and surfactants. These additives may be used alone or in combination of two or more. The amount of the additives added is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 12 parts by mass, and even more preferably 1 to 10 parts by mass, per 100 parts by mass of the total of the abrasive particles and matrix particles.

[0088] The precursor composition can be granulated using a spray dryer. In this method, the precursor composition is sprayed into heated air, and the solvent is evaporated to obtain precursor particles. The drying temperature in the spray drying is not particularly limited as long as it is a temperature at which the solvent can be evaporated. For example, when water is used as the solvent, the drying temperature may be 150 to 250°C.

[0089] 2.1.3. Firing process The firing step is a step of obtaining composite particles by firing the precursor particles obtained in the precursor particle preparation step. The firing step is a step of thermally decomposing the binder resin in the precursor particles, and fusing and appropriately bonding the matrix particles together.

[0090] The firing temperature in the firing step is preferably equal to or higher than the deformation point of the matrix particles. If the firing temperature is equal to or higher than the deformation point of the matrix particles, the matrix particles tend to fuse together and bond appropriately, which tends to further improve the stability of the composite particles. If the firing temperature is too low, the matrix particles do not bond together, making it difficult to produce the composite particles.

[0091] Furthermore, the firing temperature is preferably the yield point of the matrix particles + 150°C or less, more preferably the yield point of the matrix particles + 120°C or less, even more preferably the yield point of the matrix particles + 100°C or less, and even more preferably the yield point of the matrix particles + 80°C or less. A firing temperature of + 150°C or less than the yield point of the matrix particles tends to prevent the composite particles from bonding together, while maintaining the abrasive particle retention capacity of the composite particles within a suitable range. Furthermore, if the firing temperature is too high, the composite particles may bond together, requiring crushing after firing, resulting in a distorted shape of the composite particles and potentially impairing the abrasive particle retention capacity of the composite particles.

[0092] The firing time in the firing step is, for example, 0.5 to 30 hours.

[0093] The atmosphere in the firing step is not particularly limited, and may be an air atmosphere.

[0094] 2.2.Attachment process The adhering step is a step of adhering a curable composition containing a resin and composite particles onto a substrate. At this time, the curable composition may be adhered onto the substrate so that the polished portion forms a desired uneven pattern.

[0095] The method for adhering the curable composition onto the substrate is not particularly limited, and examples thereof include a gravure coater method, a small-diameter gravure coater method, a reverse roll coater method, a transfer roll coater method, a kiss coater method, a die coater method, a screen printing method, a spray coating method, an embossing roll method, a transfer method, etc. Among these, the screen printing method or the transfer method is preferred from the viewpoints of ease of forming a complex concavo-convex pattern and productivity.

[0096] In the screen printing method, for example, a plate having an opening pattern corresponding to the convex portions is prepared, the plate is placed on a PET film serving as a substrate layer with gaps provided, a curable composition is placed on the plate, and an appropriate pressure is applied to a squeegee, and the squeegee is moved while pressing the curable composition into the openings of the plate, thereby extruding and printing the curable composition. Thereafter, the curable composition is cured to obtain a polishing pad consisting of a patterned polishing portion on the substrate layer. In the transfer method, for example, a transfer mold having recesses corresponding to the protrusions is prepared, the transfer mold is filled with a curable composition, and the filled curable composition is bonded to a PET film serving as a base layer via an adhesive. After this, the curable composition is cured by irradiating light onto the PET film, and the film is peeled off from the transfer mold, and if necessary, the protrusions are irradiated with light again to harden, thereby obtaining a polishing pad consisting of a patterned polishing portion on the base layer.

[0097] 2.2.1. Curable composition The curable composition is not particularly limited, but examples thereof include a photocurable composition containing a photopolymerization initiator and a polymerizable compound, a thermosetting composition containing a thermal polymerization initiator and a polymerizable compound, a UV-curable resin, a curable composition containing a two-component mixed curable resin, etc. Furthermore, the curable composition may contain a crosslinker having two or more polymerizable functional groups, a dispersant, and / or a photosensitizer, etc., as needed.

[0098] The polymerizable compound is not particularly limited, but examples thereof include (meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, and polyester (meth)acrylate.

[0099] The photopolymerization initiator is not particularly limited, but examples thereof include benzophenone compounds, acetophenone compounds, and thioxanthone compounds. The thermal polymerization initiator is not particularly limited, but examples thereof include azo compounds such as 2,2'-azobisbutyronitrile, and peroxides such as benzoyl peroxide (BPO).

[0100] The thermosetting resin is not particularly limited, but examples thereof include urethane resin, unsaturated polyester resin, alkyd resin, phenol resin, epoxy resin, acrylic resin, urea resin, and formaldehyde resin.

[0101] The UV-curable resin is not particularly limited, but for example, a prepolymer with a number-average molecular weight of about 1,000 to 10,000 is suitable, and examples of materials include acrylic (methacrylic) esters, their urethane-modified products, thiocol-based materials, etc., and a reactive diluent or organic solvent can be used depending on the application. Furthermore, the two-component mixed curable resin is not particularly limited, but for example, prepolymers with different physical properties can be used.

[0102] The curable composition may contain components other than the resin, composite particles, and polymerization initiator. Examples of such components include the fillers and auxiliary particles described in detail in 1. Polishing Pad above. The compounding ratio of each component of the curable composition may be adjusted so that the content ratio of each component in the polishing part obtained by the adhesion step, curing step, etc. is the content ratio described in detail in 1. Polishing Pad above.

[0103] 2.3.Curing process The curing step is a step of curing the adhered curable composition to obtain a polishing part. The curing method is not particularly limited, but examples thereof include photocuring and thermal curing. The obtained polishing part has some composite particles exposed on the surface and other composite particles embedded in the resin. Similarly, when a filler or auxiliary particle is contained, some of these will be exposed on the surface of the polishing part.

[0104] 2.4.Other processes The method for producing a polishing pad of this embodiment may include other processes as needed. For example, after the adhesion process and before the curing process, a process of volatilizing and removing at least a portion of the volatile components in the curable composition may be included. Furthermore, after the adhesion process and before the curing process, and / or after the curing process, a process of removing a portion of the curable composition or the polishing portion may be included in order to form a desired uneven pattern. Examples of removal methods include cutting.

[0105] 3. Manufacturing method of polished products The method for producing a polished product of this embodiment is not particularly limited as long as it includes a polishing step of polishing a workpiece using the polishing pad in the presence of a coolant. The polishing step may be primary lapping (rough lapping), secondary lapping (finish lapping), or polishing, or may be a method combining two or more of these polishing steps.

[0106] The object to be polished is not particularly limited, but examples thereof include materials such as semiconductor devices and electronic components, particularly thin substrates such as Si substrates (silicon wafers), SiC (silicon carbide) substrates, GaAs (gallium arsenide) substrates, glass, and substrates for hard disks and LCDs (liquid crystal displays). Among these, the method for manufacturing a polished product of this embodiment is particularly suitable for manufacturing materials that are difficult to polish, such as glass, sapphire, SiC, GaN, and diamond, which can be used in power devices, LEDs, etc. Among these, glass materials are preferred from the viewpoint of more effectively utilizing the effects of the polishing pad of this embodiment.

[0107] 3.1. Polishing process The polishing step is a step of polishing an object to be polished using the polishing pad in the presence of a coolant. The polishing method may be any conventionally known method, and is not particularly limited.

[0108] In this polishing method, a polishing pad is first mounted in a predetermined position on a polishing apparatus. The polishing pad is attached to the polishing apparatus via the adhesive layer. Then, a workpiece held on a holding platen, positioned opposite the polishing pad, is pressed against the polishing surface. The polishing pad and / or holding platen are rotated while supplying coolant from outside as needed. The coolant supplied between the polishing pad and the workpiece reduces polishing resistance and removes polishing debris, while polishing the workpiece surface (surface to be polished). [Example]

[0109] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0110] [Particle size distribution] In the following examples, particle size distribution was measured by measuring the cumulative volumetric particle size distribution over a 10-second measurement time using a laser diffraction particle size distribution analyzer, Microtrac MT3300EXII, manufactured by Microtrac-Bell Inc. The refractive index used during measurement was 1.61, and the refractive index of the medium (deionized water) was 1.333.

[0111] [Example 1] (Preparation of composite particles) As matrix particles, glass frit having a particle size distribution as shown in Example 1 in Fig. 3 was prepared. In Fig. 3, the glass frits of Examples 1 and 2 and Comparative Example 1 were prepared by crushing the glass frit (uncrushed) of Comparative Example 2.

[0112] Next, 33 parts by mass of the above glass frit and 14 parts by mass of diamond abrasive grains with a 50% cumulative volumetric particle size of 4.3 μm were mixed, and 12 parts by mass of dextrin (manufactured by Tokai Dextrin) and 41 parts by mass of distilled water were added to prepare a precursor composition.Then, the prepared precursor composition was spray-dried (drying temperature: 200 ° C) using a spray dryer (manufactured by Ozawa Seiki Co., Ltd., OSK 55MO102) to form precursor particles.The precursor particles were then mixed with white alumina (manufactured by Fujimi Incorporated, 50% cumulative volumetric particle size: 3.0 μm) in a 2:1 ratio (mass ratio), and fired at a temperature (675 ° C) + 50 ° C relative to the yield point of the glass frit for 2 hours to obtain a mixture of composite particles consisting of glass frit and diamond abrasive grains with a 50% cumulative volumetric particle size of approximately 30 μm and white alumina.

[0113] Regarding the glass frit and diamond abrasive grains used to prepare the composite particles, the 50% cumulative volume particle diameter D50 of the glass frit Ma , the ratio of 50% cumulative volume particle size of diamond abrasive grains to glass frit D50 Ma / D50 Ab , the values ​​of the above formulas (1) and (2) in the particle size distribution of the glass frit, and the 10% cumulative volume particle size D10 of the glass frit Ma and 90% cumulative volume particle size D90 Ma is shown in Table 1.

[0114] (Preparation of Curable Composition) A precursor composition was prepared by mixing 96.9 parts by mass of a mixture of trimethylolpropane triacrylate:tris(2-hydroxyethyl)isocyanurate triacrylate = 7:3 (mass ratio) (SR368D manufactured by Sartomer Corporation), 1.6 parts by mass of a dispersant (Solsperse 32000 manufactured by Lubrizol Japan), 1.0 part by mass of a photopolymerization initiator (Irgacure 819 manufactured by BASF Japan Ltd.), and 0.5 parts by mass of a photosensitizer (Anthracure UVS-581 manufactured by Kawasaki Chemical Industries, Ltd.).

[0115] Next, the mixture of 7.2 parts by mass of the composite particles obtained as described above and 3.6 parts by mass of white alumina, 34.6 parts by mass of the precursor composition, and 54.6 parts by mass of wollastonite (50% cumulative volume particle size 15.1 μm, aspect ratio 6) was mixed to prepare a curable composition.

[0116] (Preparation of polishing pads) The obtained curable composition was poured into a molded silicone intaglio plate having a rectangular prism-shaped recess with a depth of 2 mm, a cavity opening dimension of 2.6 mm × 2.6 mm, and a spacing of 1 mm between adjacent openings, and a PET substrate was placed so as to contact the upper surface of the curable composition.The curable composition was then cured by irradiating it with ultraviolet light using an ultraviolet irradiator.Then, the obtained cured body (abrasive part) was removed from the mold and heated in a dryer at 90 degrees for 12 hours to obtain a polishing pad containing the composite particles of Example 1.

[0117] The polishing portion of the obtained polishing pad was cut, and the cross section was observed using a scanning electron microscope (SEM). An SEM image of the composite particles produced in Example 1 is shown in Figure 4. In Figure 4, the diamond abrasive grains are dark, and the matrix in which the glass frits are fused together is bright.

[0118] [Example 2, Comparative Examples 1 and 2] Polishing pads of Example 2 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that glass frits having particle size distributions as shown in Example 2 and Comparative Examples 1 and 2 in Figure 3 were used. An SEM image of the composite particles of Comparative Example 1 observed in the same manner as in Example 1 above is shown in Figure 5. In Figure 5, the diamond abrasive grains are dark, and the matrix in which the glass frits are fused together is bright.

[0119] Regarding the glass frit and diamond abrasive grains used to prepare the composite particles, the 50% cumulative volume particle diameter D50 of the glass frit Ma , the ratio of 50% cumulative volume particle size of diamond abrasive grains to glass frit D50 Ma / D50 Ab , the values ​​of the above formulas (1) and (2) in the particle size distribution of the glass frit, and the 10% cumulative volume particle size D10 of the glass frit Ma and 90% cumulative volume particle size D90 Ma is shown in Table 1.

[0120] [Table 1]

[0121] [Compression fracture strength test] The compressive fracture strength of the composite particles prepared in Examples 1 and 2 and Comparative Examples 1 and 2 was measured using a microcompression tester (MCT-W500 manufactured by Shimadzu Corporation) in accordance with the Japanese Industrial Standard (JIS R 1639-5:2007). The results are shown in Table 2.

[0122] [Table 2]

[0123] Example 1, in which the 50% cumulative volumetric particle size of the glass frit was 2.8 μm, and Example 2, in which the 50% cumulative volumetric particle size of the glass frit was 3.8 μm, exhibited high compressive fracture strengths of over 100 MPa. In particular, Example 2, which had a 50% cumulative volumetric particle size closer to that of the diamond abrasive grains, exhibited higher compressive fracture strengths. Comparative Example 1, in which the 50% cumulative volumetric particle size of the glass frit was 5.0 μm, and Comparative Example 2, in which the 50% cumulative volumetric particle size of the glass frit was 10.9 μm, exhibited relatively low compressive fracture strengths.

[0124] [Polishing test] A glass polishing test was carried out on the polishing pads of each of the Examples and Comparative Examples under the following test conditions, and the surface roughness of the glass after the test was measured. (polishing conditions) Testing machine: Speedfam tabletop polishing machine (plate size 305mmφ) Dresser: WA whetstone #1000 Dressing time: 5 to 20 minutes Load: 200g / cm 2 Rotation speed: 80 rpm Time: 10 minutes / batch x 7 batches Lubricant: Subrelve 9016 (Chemetall) 10-fold diluted aqueous solution Fluid volume: 30mL / min Polished object: Glass (50mm x 50mm)

[0125] (Surface roughness Sa of the workpiece) The surface roughness Sa of the polished surface was measured using an optical interferometer (Zgyo NewView 5010). The stability of the surface quality of the polished object over time was evaluated by calculating the rate of change in surface roughness of the polished object in the seventh batch compared to the third batch of the polishing test. (Evaluation criteria) ○: The change in surface roughness between the 7th batch and the 3rd batch is less than 20% ×: The change in surface roughness between the 7th batch and the 3rd batch is 20% or more.

[0126] [Table 3]

[0127] In Example 1, the diamond particles were uniformly dispersed in the composite particles and the compressive fracture strength was high (i.e., it is presumed that the abrasive microparticles had a high retention force in the composite particles), allowing for stable polishing. On the other hand, in Comparative Example 2, the diamond abrasive grains were unevenly distributed in the composite particles and the compressive fracture strength was relatively low, resulting in a lack of polishing stability. The surface roughness of both Example 1 and Comparative Example 2 was below 1 μm. Furthermore, like Example 1, Example 2 has excellent stability over time in the surface quality of the polished object obtained by polishing. Furthermore, like Comparative Example 2, Comparative Example 1 has poor stability over time in the surface quality of the polished object obtained by polishing.

[0128] As described above, the polishing pad of this embodiment, which contains composite particles made using abrasive microparticles and matrix particles having a predetermined particle size ratio, was able to more stably maintain the surface quality of the polished object obtained by polishing than the comparative example, which did not. [Industrial Applicability]

[0129] The polishing pad manufacturing method and polishing pad of the present invention have industrial applicability as a polishing pad manufacturing method and polishing pad suitable for lapping and polishing optical materials, semiconductor devices, glass substrates for hard disks, etc. [Explanation of symbols]

[0130] 10... Polishing pad, 11... Polishing portion, 12... Base material, 14... Composite particles, 15... Resin

Claims

1. forming composite particles from a precursor composition comprising abrasive particulates and matrix particles; depositing a curable composition comprising a resin and the composite particles onto a substrate; and a step of curing the adhered curable composition to obtain a polished portion, 50% cumulative volume particle diameter D50 of the abrasive particles Ａｂ and the 50% cumulative volume particle diameter D50 of the matrix particles Ｍａ Ratio to D50 Ｍａ / D50 Ａｂ is 0.50 to 1.1, A method for manufacturing a polishing pad.

2. In the particle size distribution of the matrix particles, 10% cumulative volume particle size D10 Ｍａ , 90% cumulative volume particle size D90 Ｍａ and the 50% cumulative volume particle size D50 Ｍａ satisfies the following formula (1): The method for producing the polishing pad according to claim 1 . Equation (1): 1.0 ≦ (D90) Ｍａ -D10 Ｍａ ) / D50 Ｍａ ≤2.0

3. In the particle size distribution of the matrix particles, 10% cumulative volume particle size D10 Ｍａ , 90% cumulative volume particle size D90 Ｍａ and the 50% cumulative volume particle size D50 Ｍａ satisfies the following formula (2): The method for producing the polishing pad according to claim 1 or 2. Equation (2): 0.35≦(D50) Ｍａ -D10 Ｍａ ) / (D90) Ｍａ -D10 Ｍａ ) ≤ 0.50

4. the ratio of the amount of the abrasive particles to the amount of the matrix particles in the precursor composition is 0.25 to 2.0 by mass; The method for producing a polishing pad according to any one of claims 1 to 3.

5. 50% cumulative volume particle diameter D50 of the matrix particles Ｍａ is 1.0 to 30 μm, The method for producing a polishing pad according to any one of claims 1 to 4.

6. 50% cumulative volume particle diameter D50 of the abrasive particles Ａｂ is 1.0 to 30 μm, The method for producing a polishing pad according to any one of claims 1 to 5.

7. the blending amount of the composite particles in the curable composition is 1.5 to 20 parts by mass with respect to 100 parts by mass of the curable composition; The method for producing a polishing pad according to any one of claims 1 to 6.

8. the matrix particles include glass frit; The method for producing a polishing pad according to any one of claims 1 to 7.

9. the abrasive particles contain at least one selected from the group consisting of diamond, cerium oxide, silicon carbide, silicon oxide, zirconium oxide, iron oxide, manganese oxide, magnesium oxide, zinc oxide, titanium oxide, aluminum oxide, zirconium silicate, boron nitride, silicon nitride, barium sulfate, and calcium carbonate; The method for producing a polishing pad according to any one of claims 1 to 8.

10. The curable composition further comprises a filler having a 50% cumulative volume particle size of 5.0 to 30 μm. The method for producing a polishing pad according to any one of claims 1 to 9.

11. The curable composition further comprises auxiliary particles having a 50% cumulative volume particle size of 0.5 to 4.5 μm. The method for producing a polishing pad according to any one of claims 1 to 10.

12. A substrate and an abrasive portion disposed on the substrate, the abrasive portion includes a resin and composite particles; the composite particles are made from a precursor composition comprising abrasive particulates and matrix particles; 50% cumulative volume particle diameter D50 of the abrasive particles Ａｂ and the 50% cumulative volume particle diameter D50 of the matrix particles Ｍａ Ratio to D50 Ｍａ / D50 Ａｂ is 0.50 to 1.1, Polishing pad.

13. A polishing pad manufactured by the method for manufacturing a polishing pad according to any one of claims 1 to 11.

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