Grinding wheel

Abstract

To provide a grinding wheel capable of suppressing deterioration of machining quality of a workpiece.SOLUTION: A grinding wheel 1 includes a wheel base 2 in which an annular groove 3 is formed on one end surface 21, and a plurality of grindstones 10 fixed in the annular groove 3 of the wheel base 2, wherein a buffer layer 5 is provided between the grindstone 10 and the annular groove 3, and the grindstone 10 and the buffer layer 5 are fixed to the annular groove 3 by an adhesive 6. The buffer layer 5 is made of a thermoplastic resin and contains a filler.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a grinding wheel. [Background technology]

[0002] Wafers (hereinafter referred to as workpieces) have multiple devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) formed on their surface. After the backside is ground to a specified thickness, the wafer is divided into individual devices using a cutting machine and used in electrical equipment such as mobile phones and personal computers.

[0003] The grinding process for grinding the back surface of the workpiece uses a known grinding device, and a grinding wheel is attached to the spindle of the grinding device to perform rough grinding and finish grinding to a predetermined thickness (see, for example, Patent Document 1).

[0004] The grinding wheel is configured by fixing a plurality of grindstones with an adhesive in an annular recess (annular groove) formed in an annular base on one end surface.

[0005] The grinding wheel is a known grinding wheel in which abrasive grains are fixed by a binder, which is made of a vitrified bond, a metal bond, a resin bond, or the like (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-288881 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-001007 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when a workpiece is machined using the grinding wheel disclosed in Patent Document 2 or the like, the machining quality may deteriorate.

[0008] In particular, this can be detrimental when grinding a workpiece made of a hard-to-cut material (such as sapphire or SiC).

[0009] The inventors have conducted extensive research and found that the gap between the annular recess of the grinding wheel and the grinding stone is currently narrow, and the amount of adhesive used to secure the grinding stone is small.

[0010] Therefore, it was thought that the processing load on the grinding wheel generated during grinding was difficult to suppress, which had a negative impact on processing quality.

[0011] An object of the present invention is to provide a grinding wheel that can suppress deterioration in the processing quality of a workpiece. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems and achieve the objectives, the grinding wheel of the present invention is a grinding wheel comprising an annular base having an annular recess formed on one end surface thereof, and a plurality of grinding wheels fixed within the annular recess of the annular base, wherein a buffer layer is provided between the grinding wheels and the annular recess, and the grinding wheels and the buffer layer are fixed to the annular recess by an adhesive.

[0013] In the grinding wheel, the buffer layer may be made of a thermoplastic resin.

[0014] In the grinding wheel, the buffer layer may contain a filler. [Effects of the Invention]

[0015] The present invention has an effect of suppressing deterioration in the processing quality of the workpiece. [Brief explanation of the drawings]

[0016] [Figure 1]FIG. 1 is a perspective view of an example of the configuration of a grinding wheel according to a first embodiment, as viewed from below. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a perspective view of the wheel base of the grinding wheel shown in FIG. 1 as seen from below. [Figure 4] FIG. 4 is a perspective view showing a state in which a buffer layer is inserted into the annular groove of the wheel base shown in FIG. [Figure 5] FIG. 5 is a perspective view showing a state in which adhesive is being filled into the annular groove of the wheel base shown in FIG. [Figure 6] FIG. 6 is a perspective view showing a state in which a grinding wheel is being inserted into the annular groove of the wheel base shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0018] [Embodiment 1] A grinding wheel according to a first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view of an example of the configuration of the grinding wheel according to the first embodiment, seen from below. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1.

[0019] (Workpiece) The grinding wheel 1 shown in FIG. 1 according to the first embodiment is a processing device that is attached to the lower end of a spindle of a grinding unit of a grinding device (not shown) and grinds a workpiece to be processed, thereby thinning the workpiece to a predetermined finishing thickness.

[0020] In the first embodiment, the workpiece to be processed is a wafer such as a disk-shaped semiconductor wafer or an optical device wafer, with a substrate made of silicon, sapphire, gallium arsenide, SiC, etc. The workpiece has devices formed in each of a plurality of regions partitioned by a plurality of intersecting (orthogonal in the first embodiment) planned dividing lines on the surface of the substrate.

[0021] The device may be, for example, an integrated circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), a MEMS (Micro Electro Mechanical Systems), various types of memory (semiconductor memory device), an LED (Light Emitting Diode), or a power device.

[0022] In the first embodiment, the workpiece has a substrate made of sapphire, SiC, or the like, which is a difficult-to-cut material that is more difficult to grind than silicon.

[0023] (grinding wheel) Next, a description will be given of a grinding wheel 1 according to embodiment 1. As shown in Figures 1 and 2, the grinding wheel 1 includes an annular wheel base 2 (corresponding to an annular base) attached to the lower end of a spindle of a grinding unit, and a plurality of grinding stones 10.

[0024] The wheel base 2 is formed in an annular shape, and an annular groove 3 (annular recess) is formed in one end face 21 of the annular shape that faces the workpiece during grinding. The annular groove 3 is formed coaxially with the one end face 21 of the wheel base 2, and is a groove recessed from the one end face 21. The annular groove 3 is formed so that its width and its depth from the one end face 21 to the bottom face 31 are constant around the entire circumference. In the first embodiment, the depth of the annular groove 3 from the one end face 21 to the bottom face 31 (shown in FIG. 2) is 2 mm.

[0025] In addition, in embodiment 1, a grinding water supply passage 4 penetrates the wheel base 2 from one end face 21 to the other annular end face 22, supplying grinding water to the workpiece being ground by the grinding wheel 1.

[0026] The grinding wheel 10 is configured as a so-called segment grinding wheel, which is formed into a single mass by mixing abrasive grains such as diamond or CBN (Cubic Boron Nitride) with a bonding material (also called a bond material) made of metal, ceramic, resin, etc. In the first embodiment, the grinding wheel 10 is formed to have a constant thickness and width over its entire length, and is curved in an arc shape with the same curvature as the annular groove 3.

[0027] A plurality of grinding wheels 10 are arranged at equal intervals in the circumferential direction of the wheel base 2 and the annular groove 3, with a portion of the grinding wheels 10 inserted into the annular groove 3 and the portion fixed in the annular groove 3.

[0028] 2, the grinding wheel 1 includes a buffer layer 5 between each grinding stone 10 and the bottom surface 31 of the annular groove 3. The buffer layer 5 is formed in an annular shape with a constant width and thickness over the entire circumference. In the first embodiment, the buffer layer 5 contains a thermoplastic resin and a filler, but in the present invention, the buffer layer 5 may contain only a thermoplastic resin.

[0029] In the first embodiment, the thermoplastic resin constituting the buffer layer 5 is an acrylic resin, a PLA (polylactic acid) resin, an ABS resin, or the like. In the first embodiment, the filler constituting the buffer layer 5 is alumina (Al2O3), silicon carbide (SiC), or the like. In the first embodiment, the thickness of the buffer layer 5 is 1 mm.

[0030] 2, the plurality of grinding wheels 10 are fixed to the wheel base 2 by adhesive 6 filled between both inner circumferential surfaces 32 of the annular groove 3. That is, the grinding wheel 1 is fixed to the annular groove 3 of the wheel base 2 by the adhesive 6, with the grinding wheels 10 and the buffer layer 5.

[0031] (Assembly Instructions) Next, a method for assembling the grinding wheel 1 shown in Figures 1 and 2 will be described. Figure 3 is a perspective view of the wheel base of the grinding wheel shown in Figure 1, seen from below. Figure 4 is a perspective view showing the state in which a buffer layer is inserted into the annular groove of the wheel base shown in Figure 3. Figure 5 is a perspective view showing the state in which an adhesive is filled into the annular groove of the wheel base shown in Figure 4. Figure 6 is a perspective view showing the state in which a grinding stone is inserted into the annular groove of the wheel base shown in Figure 5.

[0032] When assembling the grinding wheel 1, first, the wheel base 2 shown in Fig. 3 is prepared. Then, as shown in Fig. 4, the buffer layer 5 is placed opposite the annular groove 3, and the buffer layer 5 is inserted into the annular groove 3 of the wheel base 2. As shown in Fig. 5, adhesive 6 is filled from an adhesive supply unit 100 into the annular groove 3 of the wheel base 2 that houses the buffer layer 5. As shown in Fig. 6, a grinding wheel 10 is inserted into the annular groove 3 that houses the buffer layer 5 of the wheel base 2 and is filled with adhesive 6, and the adhesive 6 is cured to fix the grinding wheel 10 to the wheel base 2, thereby assembling the grinding wheel 1.

[0033] The grinding wheel 1 according to the first embodiment described above has a buffer layer 5 containing a thermoplastic resin disposed between the bottom surface 31 of the annular groove 3 of the wheel base 2 and the grinding wheel 10. As a result, the grinding wheel 1 according to the first embodiment can suppress the load on the grinding wheel 10 by the buffer layer 5 being slightly deformed in a direction that reduces its thickness due to heat generated during the grinding process.

[0034] As a result, the grinding wheel 1 according to the first embodiment has the effect of suppressing deterioration in processing quality.

[0035] Next, the inventors of the present invention confirmed the effects of the grinding wheel 1 according to embodiment 1. The results are shown in Table 1 below.

[0036] [Table 1]

[0037] The product of the present invention in Table 1 is a grinding wheel 1 according to embodiment 1 in which the buffer layer 5 is made of PLA resin, and the comparative example in Table 1 is a grinding wheel in which the grinding wheel 10 is fixed to the wheel base 2 with adhesive 6 applied to the bottom surface 31 and both inner peripheral surfaces 32 of the annular groove 3 without providing a buffer layer 5. The wheel bases 2 of the product of the present invention and the comparative example are the same, and the grinding wheels 10 of the product of the present invention and the comparative example are the same.

[0038] In checking Table 1, the arithmetic mean roughness (Ra) and maximum height (Ry), which are parameters representing the surface roughness of the ground surface (the surface that has been ground) after grinding the same type of workpiece using the grinding wheels 1 of the present invention and the comparative example, were measured.

[0039] In Table 1, the comparative example had an arithmetic mean roughness (Ra) of 0.044 μm and a maximum height (Ry) of 0.377 μm. In contrast to this comparative example, the product of the present invention had an arithmetic mean roughness (Ra) of 0.035 μm and a maximum height (Ry) of 0.328 μm.

[0040] As can be seen from Table 1, by providing a buffer layer 5 between the grinding wheel 10 and the annular groove 3, it is possible to suppress the surface roughness of the grinding surface and to suppress a decrease in the processing quality of the workpiece.

[0041] The present invention is not limited to the above-described embodiment, and can be implemented in various modifications without departing from the gist of the present invention. [Explanation of symbols]

[0042] 1 grinding wheel 2 Wheel base (circular base) 3 Annular groove (annular recess) 5 Buffer layer 6. Adhesive 10. Whetstone 21 One end face

Claims

1. A grinding wheel comprising: an annular base having an annular recess formed on one end surface thereof; and a plurality of grinding stones fixed within the annular recess of the annular base, a buffer layer is provided between the grinding wheel and the annular recess; The grinding wheel and the buffer layer are fixed in the annular recess by an adhesive. Grinding wheel.

2. 10. The grinding wheel of claim 1, wherein the buffer layer is a thermoplastic resin.

3. 3. The grinding wheel according to claim 1, wherein the buffer layer contains a filler.

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