Polishing pad

Abstract

To provide a polishing pad which hardly causes polishing failure even for a polishing object having an acute-angled part and a fine part, is excellent in cleanability of the polishing object after polishing, can simplify management, recovery and circulation of polishing liquid, and can lower polishing cost.SOLUTION: A polishing pad 1 is a sheet-like polishing pad having a base material which is composed of a binder resin and is formed with a plurality of pores, polishing particles held in the base material or pores, and fibers held in the base material or the pores. The polishing pad 1 has sufficient flexibility to be held on fixed surfaces 5a and 7a formed of curved surfaces.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a polishing pad. [Background technology]

[0002] Patent Document 1 discloses a conventional polishing pad. This polishing pad is made of a binder resin and has a base material with multiple pores formed therein, and abrasive particles held in the base material or the pores. This polishing pad is an abrasive-containing polishing pad, also known as an LHA (Loosely Held Abrasive) pad.

[0003] This polishing pad can polish the surface to be polished by moving the surface to be polished of a disc-shaped wafer and the polishing surface of the polishing pad relative to each other under a predetermined surface pressure. In this case, it is sufficient to interpose a polishing liquid containing no abrasive particles between the surface to be polished of the wafer and the polishing surface of the polishing pad, so that there are few particles, which are abrasive particles, remaining on the wafer after polishing, and therefore the wafer can be easily cleaned after polishing. In addition, since a polishing liquid containing no abrasive grains can be used, the management, recovery, and circulation of the polishing liquid can be simplified, and the polishing cost can be reduced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-49256 Summary of the Invention [Problem to be solved by the invention]

[0005] However, according to tests conducted by the inventors, conventional polishing pads are designed to polish the surface of a disc-shaped wafer, so when the object to be polished has sharp or small portions, the polishing surface does not sufficiently contact those portions, and only localized polishing can be performed. In other words, this polishing pad is prone to producing poor polishing results when polishing such objects.

[0006] For example, when a metal or resin object is created using a 3D printer, the layer marks that occur during molding remain on the surface, causing a deterioration in surface quality. If such an object is polished using the conventional polishing pads described above, some of the layer marks will remain even after attempting to remove them, raising concerns that the strength of the object will be significantly reduced.

[0007] The present invention has been made in consideration of the above-mentioned conventional situation, and aims to solve the problem of providing a polishing pad that is less likely to cause polishing defects even when the object to be polished has sharp angles or small parts, is excellent in terms of cleaning the object to be polished after polishing, simplifies the management, recovery, and circulation of the polishing liquid, and reduces polishing costs. [Means for solving the problem]

[0008] The polishing pad of the present invention is a sheet-like polishing pad having a base material made of a binder resin and having a plurality of pores formed therein, abrasive particles held in the base material or the pores, and fibers held in the base material or the pores, It is characterized by its flexibility, which allows it to be held on a fixing surface formed by a curved surface.

[0009] The polishing pad of the present invention has flexibility that allows it to be held on a fixed surface formed by a curved surface, so even if the object to be polished has sharp angles or small areas, the polishing surface of the polishing pad can be sufficiently abutted against those areas, making it easy to polish the entire object.

[0010] In addition, since the polishing pad of the present invention has an abrasive layer containing a binder resin and countless abrasive particles and fibers as the polishing surface, it is possible to use a polishing liquid that does not contain abrasive particles, and since there are few particles (abrasive particles) remaining on the object to be polished after polishing, it is excellent in cleaning the object to be polished after polishing. Furthermore, since a polishing liquid that does not contain abrasive particles can be used, it is possible to simplify the management, recovery, and circulation of the polishing liquid, and it is possible to reduce the polishing cost. [Effects of the Invention]

[0011] The polishing pad of the present invention is less likely to cause polishing defects even when polishing an object having sharp angles or small parts. Furthermore, this polishing pad has excellent cleanability for the object after polishing, simplifies the management, recovery, and circulation of the polishing liquid, and reduces polishing costs. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing the polishing pads of test samples 1 to 14 and comparative samples 1 and 2. As shown in FIG. [Figure 2] FIG. 2 is a cross-sectional view of polishing pads of test samples 1 to 14, showing flexibility according to test 1. [Figure 3] FIG. 3 is a SEM photograph of the polishing pad of Test Sample 3 at 2000x magnification. [Figure 4] FIG. 4 is a SEM photograph of the polishing pad of Test Sample 3 at 5000x magnification. [Figure 5] FIG. 5 is a SEM photograph of the polishing pad of specimen 13 at 2000x magnification. [Figure 6] FIG. 6 is a SEM photograph of the polishing pad of specimen 13 at 5000x magnification. DETAILED DESCRIPTION OF THE INVENTION

[0013] The binder resin may be polyvinylidene fluoride (PVDF), polyethersulfone (PES), polyvinyl fluoride, vinyl fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, polyethylene, polymethyl methacrylate, or the like. These may be used alone or in combination of two or more. The inventors have confirmed the effects of the present invention by using polyvinylidene fluoride as the binder resin.

[0014] The abrasive particles may be diamond, silica, ceria, alumina, zirconia, titania, manganese oxide, barium carbonate, chromium oxide, boron carbide, iron oxide, etc. These may be used alone or in combination of two or more. The inventors have confirmed the effects of the present invention by using diamond as the abrasive particles.

[0015] The fibers may be polypropylene fibers, aramid fibers, glass fibers, cellulose fibers, nylon fibers, vinylon fibers, polyester fibers, polyethylene fibers, polyolefin fibers, rayon fibers, low-density polyethylene resins, ethylene vinyl acetate resins, synthetic rubbers, copolymer polyamide resins, copolymer polyester resins, etc. These may be used alone or in combination of two or more. It is also possible to select the shape, such as fiber length and thickness. The inventors confirmed the effects of the present invention by using polypropylene fibers, which have excellent chemical resistance.

[0016] The fibers of the polishing pad may be based on a preformed or non-preformed fiber web. A fiber web is a layer of fibers arranged in a longitudinal, crossed, or random fiber orientation. A nonwoven fabric is a fiber web in which the fibers are bonded together.

[0017] The polishing pad preferably contains a filler held within the matrix or pores. The filler prevents the abrasive particles from agglomerating, elastically holds the abrasive particles, and reduces the reaction force acting on the abrasive particles during polishing. Furthermore, depending on the filler material, wear resistance can be improved. The filler can be an inorganic powder, inorganic fiber, resin powder, resin fiber, metal powder, or metal fiber, which are softer than the abrasive particles.

[0018] Examples of inorganic powders used as fillers include silica, alumina, talc, SiC, calcium carbonate, clay, etc. Examples of inorganic fibers used as fillers include glass fiber, carbon fiber, etc. Examples of resin powders and resin fibers used as fillers include powders or fibers of already cured thermosetting resins or thermoplastic resins. Examples of metal powders used as fillers include iron, copper, aluminum, nickel, etc. Examples of metal fibers used as fillers include iron fibers, copper fibers, aluminum fibers, etc. These may be used alone or in combination of two or more types. The inventors confirmed the effects of the present invention by using silica particles as the filler.

[0019] The polishing pad of the present invention can be manufactured by a manufacturing method including a preparation step, an impregnation step, and a solidification step. In the preparation step, a paste and a fiber web are prepared. The paste contains a binder resin, abrasive particles, and a solvent, or a binder resin, abrasive particles, a filler, and a solvent. In the impregnation step, the fiber web is impregnated with the paste to form an impregnated body. In the solidification step, the solvent is removed from the impregnated body to solidify the binder resin.

[0020] The polishing pad obtained by this manufacturing method includes a fiber web and a binder resin and abrasive particles contained therein, or a fiber web and a binder resin, abrasive particles, and a filler contained therein. In this case, the productivity of the polishing pad is high because the fibers are pre-formed into a fiber web.

[0021] As the solvent, dimethylformamide, dimethyl sulfoxide, acetone, ethyl acetate, methyl ethyl ketone, etc. can be used. These may be used alone or in combination of two or more. The solvent is selected according to the binder resin.

[0022] When a polishing liquid is used, one that does not contain abrasive particles can be used. The polishing liquid may be pure water, oil-based, or may contain an acidic or alkaline chemical.

[0023] (Test product / comparison product) Polishing pads 1 of test samples 1 to 14 and comparative samples 1 and 2 were manufactured by the following manufacturing method.

[0024] In the preparation step, the following binder resin, abrasive particles, filler, solvent and fiber web were prepared. (binder resin) PVDF (Polyvinylidene Fluoride) TPU (thermoplastic polyurethane) (abrasive particles) Diamond particles (average particle size: 5 μm) (filler) Silica (SiO2) (average particle size: 200 nm) (solvent) N-Methyl-2-pyrrolidone (fiber web) 100% PP (polypropylene) fiber, fiber diameter 40μm and 30μm, 3.0mm thickness, basis weight 200g / m 2

[0025] [Table 1]

[0026] The binder resin, abrasive particles, filler, and solvent were mixed in the mass percentages shown in Table 1 to form a paste. If a filler was added, the filler was mixed with the solvent to form a slurry. Alternatively, the abrasive particles and binder resin were dry-mixed to form a mixture. The mixture was then mixed with the solvent or slurry to form a paste.

[0027] In the impregnation process, the paste is formed into a sheet on a flat base, and a fiber web is placed on top of the sheet. The paste is then formed into a sheet on the fiber web. The resulting laminate is vacuum-pressurized in the stacking direction to form a pressurized laminate.

[0028] Next, in the solidification process, the pressurized laminate is dried to remove the solvent from the pressurized laminate. This solidifies the binder resin. The surface of the resulting solidified body is buffed to form a polishing surface. This results in a sheet-like polishing pad 1, as shown in Figure 1. In this case, the fibers are preformed into a fiber web, so the productivity of the polishing pad 1 is high.

[0029] An SEM photograph of polishing pad 1 of test sample 3 at 2000x magnification is shown in Figure 3, and an SEM photograph of that at 5000x magnification is shown in Figure 4. Also, an SEM photograph of polishing pad 1 of test sample 13 at 2000x magnification is shown in Figure 5, and an SEM photograph of that at 5000x magnification is shown in Figure 6.

[0030] As can be seen from Figures 3 to 6, the polishing pads 1 of test samples 7, 9, 11, and 14 and comparison samples 1 and 2 contain a fiber web that constitutes fibers, a binder resin and abrasive particles contained within the fiber web, but do not contain a filler. The other polishing pads 1 also contain a filler within the fiber web.

[0031] The physical properties of the polishing pads 1 of test samples 1 to 14 and comparison samples 1 and 2 were density (g / cm 3 ), Durometer A hardness and elastic modulus (N / mm 2 The results are shown in Table 2.

[0032] [Table 2]

[0033] The composition ratio (volume %) of the polishing pad 1 was also measured for test samples 1 to 14 and comparative samples 1 and 2. The results are shown in Table 3.

[0034] [Table 3]

[0035] (Test 1) As shown in FIG. 1, two polishing pads 1 were prepared for each of test samples 1 to 14 and comparison samples 1 and 2. A first double-sided tape 3a with strong adhesive strength and a second double-sided tape 3b with weak adhesive strength were also prepared. The first double-sided tape 3a had an adhesive strength of 10 (N / 25 mm), and the second double-sided tape 3b had an adhesive strength of 3 (N / 25 mm). Each polishing pad 1 had the first double-sided tape 3a attached to its back surface, the side opposite the polishing surface, and each polishing pad 1 had the second double-sided tape 3b attached to its back surface.

[0036] Additionally, a first cylindrical body 5 (radius of curvature 25 mm) having a diameter of 50 mm and a second cylindrical body 7 (radius of curvature 5 mm) having a diameter of 10 mm were prepared. The first and second cylindrical bodies were made of stainless steel SUS304, and their surfaces were mirror-finished.

[0037] The release paper was peeled off from the first double-sided tape 3a, and each polishing pad 1 was attached once around the outer circumferential surface 5a of the first cylinder 5 and once around the outer circumferential surface 7a of the second cylinder 7. The release paper was peeled off from the second double-sided tape 3b, and each polishing pad 1 was attached once around the outer circumferential surface 5a of the first cylinder 5 and once around the outer circumferential surface 7a of the second cylinder 7.

[0038] At this time, if the polishing pad 1 did not tear and could be bent without creating a gap between it and the peripheral surface, it was marked as ○, and if the polishing pad 1 tore or created a gap between it and the peripheral surface, it was marked as ×. In addition, if it remained attached for more than one hour, it was marked as ○, if it was attached for more than 30 minutes but less than one hour, it was marked as △, and if it peeled off in less than 30 minutes, it was marked as ×. The flexibility of the polishing pad 1 was evaluated in this way. The results are shown in Table 4.

[0039] [Table 4]

[0040] Table 4 shows that the polishing pads 1 of test samples 1 to 14 have flexibility that allows them to be held by the outer circumferential surfaces 5a and 7a of the curved first and second cylindrical bodies 5 and 7. On the other hand, the polishing pads 1 of comparison samples 1 and 2 do not have the flexibility defined in the present invention.

[0041] (Test 2) In Test 2, a copper object to be polished with a complex shape was prepared. This object to be polished had multiple sharp or fine convex portions with a curvature radius of 5 mm.

[0042] The polishing pads 1 of test samples 1 to 14 and comparison samples 1 to 3 were held with the fingers and polished using water as the polishing liquid. During this process, the polishing pad 1 was brought into contact with each convex portion of the polishing object at an angle of 90° or at an angle of 45°. The polishing pads 1 of comparison samples 1 and 2 were of the same type as those used in test 1. The polishing pad 1 of test sample 3 was made of a commercially available nonwoven fabric (#4000).

[0043] The presence or absence of polishing residue was evaluated as ◎ if polishing could be completed without any residue within 30 seconds, 〇 if polishing could be completed without any residue within 30 to 60 seconds, and × if polishing for 60 seconds or more was required. The surface roughness of the polished object after polishing was evaluated as ◎ if Ra 1 μm or less, 〇 if Ra 1 μm to 5 μm or less, and × if Ra 5 μm or more. The results are shown in Table 5.

[0044] [Table 5]

[0045] Table 5 shows that the polishing pads 1 of test samples 1 to 14 can easily polish the entire surface even when the object to be polished has sharp angles or small areas by fully contacting the polishing surface of the polishing pad with those areas. In polishing pads 1 containing filler such as test sample 1, the filler prevents the abrasive particles from agglomerating and elastically holds the abrasive particles, mitigating the reaction force acting on the abrasive particles during polishing. On the other hand, the polishing pads 1 of comparison samples 1 to 3 can only perform localized polishing.

[0046] In addition, the polishing pads 1 of test samples 1 to 14 have an abrasive layer containing a binder resin and countless abrasive particles and fibers as the polishing surface, so they can use a polishing liquid that does not contain abrasive particles, and since there are fewer abrasive particles remaining on the object to be polished after polishing, they have excellent cleaning properties for the object to be polished after polishing.In addition, because a polishing liquid that does not contain abrasive particles can be used, the management, recovery, and circulation of the polishing liquid can be simplified, and polishing costs can be reduced.

[0047] Therefore, polishing defects are unlikely to occur even when polishing objects having sharp angles or small areas with the polishing pads 1 of test samples 1 to 14. Furthermore, these polishing pads 1 have excellent cleaning properties for the object to be polished after polishing, and can simplify the management, recovery, and circulation of the polishing liquid, thereby reducing polishing costs.

[0048] The present invention has been described above in accordance with test samples 1 to 14, but it goes without saying that the present invention is not limited to the test samples 1 to 15, and can be modified and applied as appropriate within the scope of the invention.

[0049] For example, in Test 2, a polishing object made of copper was polished, but the polishing pad of the present invention can also be applied to polishing objects made of other metals or resins. [Industrial Applicability]

[0050] The present invention can be used in a method and apparatus for polishing an object having sharp edges or fine parts. [Explanation of symbols]

[0051] 1...Polishing pad 5, 7...Cylindrical

Claims

1. A sheet-like polishing pad comprising a base material made of a binder resin and having a plurality of pores formed therein, abrasive particles held in the base material or the pores, and fibers held in the base material or the pores, A polishing pad characterized by having flexibility that allows it to be held on a fixing surface formed by a curved surface.

2. 2. The polishing pad according to claim 1, wherein said flexibility is a property such that when the outer peripheral surface of a cylindrical body having a radius of curvature of 25 mm is used as said fixing surface, it can be adhered around one circumference without cracking or gaps.

3. 3. The polishing pad according to claim 2, wherein said flexibility is a property such that when the outer peripheral surface of a cylindrical body having a radius of curvature of 5 mm is used as said fixing surface, one circumference can be bonded without cracking or gaps.

4. 4. A polishing pad according to claim 1, further comprising a filler held within the base material or the pores, which prevents the abrasive particles from agglomerating, holds the abrasive particles elastically, and alleviates the reaction force acting on the abrasive particles during polishing.

5. the binder resin is polyvinylidene fluoride, the abrasive particles are diamond; the fibers are polypropylene; the filler is silica particles; The binder resin is 5.3 to 18.8% by volume, The pores are 68.6 to 76.8% by volume, The abrasive particles are 0.7 to 20.4% by volume, The fibers are 2.4 to 6.7% by volume, 5. The polishing pad according to claim 4, wherein the filler is present in an amount of 0 to 15.0% by volume.

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