Grinding wheel

Abstract

To provide a grinding wheel which is easy to handle when being taken out from a case, although the grinding wheel comprises grindstones having a bond material containing phenolic resin that discharges ammonia gas.SOLUTION: A grinding wheel for grinding a workpiece includes: a wheel base in which an annular groove is formed on one surface; a plurality of grindstones that are inserted to each of the grooves and that are provided so as to protrude from the one surface; and an adhesive material for fixing the plurality of grindstones in the groove. The grindstones include a bond material containing phenolic resin that discharges ammonia gas, and abrasive grains dispersed in the bond material. In the adhesive material, an adsorbent for adsorbing the ammonia gas is dispersed.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Chips of devices such as ICs (Integrated Circuits) are essential components in various electronic devices such as mobile phones and personal computers. Such chips are manufactured, for example, by thinning a workpiece such as a wafer having multiple devices formed on its front surface and then dividing the workpiece along the boundaries of the multiple devices.

[0003] One method for thinning a workpiece is to grind the back side of the workpiece in a grinding device. This grinding device includes, for example, a chuck table for holding the front side of the workpiece, and a spindle provided above the chuck table and having a grinding wheel attached to its lower end (see, for example, Patent Document 1).

[0004] A grinding wheel generally includes a wheel base having an annular groove formed on one side thereof, a number of grindstones each inserted into the groove and protruding from one side of the wheel base, and an adhesive for fixing the grindstones in the groove. The grindstones also include a bond material and abrasive grains dispersed in the bond material.

[0005] In the grinding device, for example, a chuck table that holds the front side of the workpiece and a grinding wheel attached to the lower end of the spindle are both rotated, and multiple grindstones are brought into contact with the back side of the workpiece, thereby grinding the back side of the workpiece and thinning the workpiece. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-124690 A Summary of the Invention [Problem to be solved by the invention]

[0007] Grinding wheels are generally stored in a special case. However, phenolic resin that releases ammonia gas may be used as a bond material for the grinding stone included in the grinding wheel. In this case, the concentration of ammonia gas in the case may become high. Furthermore, since ammonia gas has a pungent odor, it may be difficult to handle the grinding wheel when removing it from the case.

[0008] In view of this, an object of the present invention is to provide a grinding wheel that is equipped with a grinding stone having a bond material containing a phenolic resin that releases ammonia gas, but that is easy to handle when removed from the case. [Means for solving the problem]

[0009] According to the present invention, there is provided a grinding wheel for grinding a workpiece, comprising a wheel base having an annular groove formed on one surface thereof, a plurality of grinding stones each inserted into the groove and arranged so as to protrude from the one surface thereof, and an adhesive for fixing the plurality of grinding stones in the grooves, wherein the grinding stones have a bond material containing a phenolic resin that releases ammonia gas and abrasive grains dispersed in the bond material, and the adhesive has an adsorbent dispersed therein for adsorbing the ammonia gas.

[0010] Preferably, the adsorbent comprises at least one of zeolite, silica gel, or activated carbon. Effect of the Invention

[0011] In the grinding wheel of the present invention, an adsorbent for adsorbing ammonia gas is dispersed in the adhesive. In this case, an increase in the concentration of ammonia gas in the case for storing the grinding wheel is suppressed. Therefore, the grinding wheel is easy to handle when removed from the case. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1(A) is a top view showing a schematic diagram of an example of a grinding wheel, FIG. 1(B) is a cross-sectional view showing a schematic diagram of an example of a grinding wheel, and FIG. 1(C) is a bottom view showing a schematic diagram of an example of a grinding wheel. [Diagram 2] FIG. 2 is a flow chart that illustrates a schematic example of a method for manufacturing the grinding wheels shown in FIGS. 1(A), 1(B), and 1(C). [Diagram 3] 3(A) is a side view showing the dispersion step shown in FIG. 2, FIG. 3(B) is a cross-sectional view showing the supply step shown in FIG. 2, and FIG. 3(C) is a cross-sectional view showing the insertion step shown in FIG. 2. [Figure 4] FIG. 4(A) is a top view diagrammatically showing another example of a grinding wheel, FIG. 4(B) is a cross-sectional view diagrammatically showing another example of a grinding wheel, and FIG. 4(C) is a bottom view diagrammatically showing another example of a grinding wheel. [Diagram 5] FIG. 5 is a flow chart that illustrates a schematic example of a method for manufacturing the grinding wheels shown in FIGS. 4(A), 4(B), and 4(C). [Figure 6] 6(A) is a cross-sectional view that illustrates the first supply step shown in FIG. 5, and FIG. 6(B) is a cross-sectional view that illustrates the second supply step shown in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1(A) is a top view showing an example of a grinding wheel, Fig. 1(B) is a cross-sectional view showing an example of a grinding wheel, and Fig. 1(C) is a bottom view showing an example of a grinding wheel.

[0014] 1(A), 1(B), and 1(C) has an annular wheel base 4 made of a metal such as an aluminum alloy. The wheel base 4 has a generally flat upper surface (other surface) 4a and a lower surface (one surface) 4b that is narrower in width (length along the radial direction of the wheel base 4) than the other surface 4a.

[0015] A plurality of screw holes 4c are formed on the other surface 4a of the wheel base 4 at approximately equal intervals along the circumferential direction of the wheel base 4. The grinding wheel 2 is attached to the tip of a spindle provided in a grinding device by using bolts that are screwed into the plurality of screw holes 4c.

[0016] Further, an annular groove 4d having a rectangular cross section is formed on one surface 4b of the wheel base 4. The width of this groove 4d (the length along the radial direction of the wheel base 4) is, for example, 2.1 mm to 5.1 mm, and the depth is, for example, 1 mm to 2 mm. A plurality of grindstones 6 are inserted into this groove 4d so as to be spaced apart from each other along the circumferential direction of the wheel base 4.

[0017] Each grinding wheel 6 has a bond material containing a phenolic resin that releases ammonia gas and abrasive grains dispersed in the bond material. The abrasive grains are made of, for example, diamond, cBN (cubic boron nitride), etc. Each grinding wheel 6 has a shape like a rectangular parallelepiped curved with a curvature similar to that of the groove 4d.

[0018] The width of each grindstone 6 (the length along the radial direction of the wheel base 4) is, for example, 2 mm to 5 mm, and the height (the length along the thickness direction of the wheel base 4) is, for example, 7 mm to 10 mm. Furthermore, the lower end faces (grinding surfaces) of the multiple grindstones 6 are positioned on approximately the same plane.

[0019] In addition, an adhesive 8 is provided in a groove 4d formed on one surface 4b of the wheel base 4 to fix multiple grinding wheels 6, and each grinding wheel 6 is embedded in the adhesive 8 by, for example, a portion of 1 mm to 2 mm from one end thereof.

[0020] The adhesive 8 is, for example, a two-part mixed adhesive formed by mixing a base agent and a curing agent so that the volume ratio is 1:1. The base agent is, for example, an epoxy resin used as the base agent of a two-part mixed reactive epoxy adhesive. The curing agent is, for example, a polyamide resin (for example, polyamidoamine) used as the curing agent of a two-part mixed reactive epoxy adhesive.

[0021] In addition, an adsorbent 10 for adsorbing ammonia gas is dispersed as a filler in the adhesive 8. The adsorbent includes at least one of zeolite, silica gel, and activated carbon, for example. The adhesive 8 and the adsorbent are configured such that the volume ratio of the base agent and hardener of the adhesive 8 to the adsorbent is 1:1:1, for example.

[0022] Fig. 2 is a flow chart showing a typical example of a method for manufacturing the grinding wheel 2. In this method, first, the adsorbent 10 is dispersed in the liquid adhesive (dispersion step S1). Fig. 3(A) is a side view showing a typical state of the dispersion step S1. In this dispersion step S1, for example, the liquid adhesive 14 and the adsorbent 10 are placed in a container 12 such as a beaker, and then the inside of the container 12 is stirred using a stirring rod 16.

[0023] After the dispersion step S1, the liquid adhesive 14 in which the adsorbent 10 is dispersed is supplied to the groove 4d formed on one surface 4b of the wheel base 4 (supply step S2). Fig. 3(B) is a cross-sectional view showing a schematic view of the supply step S2. In this supply step S2, for example, the liquid adhesive 14 in which the adsorbent 10 is dispersed is dripped from a container 12 toward the groove 4d from above the wheel base 4 arranged so that the groove 4d faces upward.

[0024] After the supply step S2, the grindstones 6 are inserted into the grooves 4d (insertion step S3). Fig. 3(C) is a cross-sectional view showing the insertion step S3. In the insertion step S3, the grindstones 6 are inserted into the grooves 4d such that one end of each of the grindstones 6 is submerged in the liquid adhesive 14.

[0025] After the insertion step S3, the liquid adhesive 14 is dried (drying step S4). In this drying step S4, for example, the wheel base 4 and the plurality of grinding wheels 6 are left at room temperature for 10 to 14 hours (for example, 12 hours) or at 70°C to 90°C (for example, 80°C) for 1 to 3 hours (for example, 2 hours). This causes the liquid adhesive 14 to dry and turn into a hardened adhesive 8. As a result, the grinding wheel 2 is manufactured.

[0026] FIG. 4(A) is a top view diagrammatically showing another example of a grinding wheel, FIG. 4(B) is a cross-sectional view diagrammatically showing another example of a grinding wheel, and FIG. 4(C) is a bottom view diagrammatically showing another example of a grinding wheel.

[0027] The grinding wheel 18 shown in Figures 4(A), 4(B) and 4(C) has a structure similar to that of the grinding wheel 2 shown in Figures 1(A), 1(B) and 1(C), except that the adsorbent 10 is not evenly dispersed in the adhesive 8, but is dispersed so as to be unevenly distributed near the exposed surface of the adhesive 8 (the surface on the side of one surface 4b of the wheel base 4).

[0028] Fig. 5 is a flow chart showing a schematic example of a method for manufacturing the grinding wheel 18. In this method, first, the liquid adhesive 14 is supplied to the groove 4d formed on one surface 4b of the wheel base 4 (first supplying step S5). Fig. 6(A) is a side view showing a schematic view of the first supplying step S5. In this first supplying step S5, for example, the liquid adhesive 14 is dripped from a container 20 such as a beaker containing the liquid adhesive 14 toward the groove 4d from above the wheel base 4 arranged so that the groove 4d faces upward.

[0029] After the first supply step S5, the adsorbent 10 is supplied to the groove 4d (second supply step S6). FIG. 6(B) is a cross-sectional view that shows a schematic view of the second supply step S6. In the second supply step S6, for example, the adsorbent 10 is dropped from the container 22 toward the groove 4d while rotating a container 22 such as a beaker containing the adsorbent 10 so as to follow the groove 4d in a plan view. Note that since the liquid adhesive 14 is a highly viscous liquid, the adsorbent 10 does not sink into the liquid adhesive 14 but remains on it.

[0030] After the second supply step S6, as described above, a plurality of grindstones 6 are inserted into the groove 4d (insertion step S3), and then the liquid adhesive 14 is dried (drying step S4). As a result, at least a portion of the adsorbent 10 is fixed, and a hardened adhesive 8 is obtained. Furthermore, the groove 4d is washed to remove the adsorbent 10 that is not fixed by the adhesive 8. As a result, the grinding wheel 18 is manufactured.

[0031] In the above-mentioned grinding wheels 2, 18, the adsorbent 10 for adsorbing ammonia gas is dispersed in the adhesive 8. In this case, an increase in the concentration of ammonia gas in the case for storing the grinding wheels 2, 18 is suppressed. Therefore, the grinding wheels 2, 18 are easy to handle when taken out of the case.

[0032] The structures and methods according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. [Industrial Applicability]

[0033] The grinding wheels 2, 18 can be used, for example, when grinding the back side of a workpiece, such as a wafer having a plurality of devices formed on the front side thereof, in order to thin the workpiece. [Explanation of symbols]

[0034] 2: Grinding wheel 4: Wheel base (4a: top surface (other surface), 4b: bottom surface (one surface)) (4c: screw hole, 4d: groove) 6: Grindstone 8: Adhesive (hardened adhesive) 10: Adsorbent 12: Container 14: Liquid adhesive 16: Stirring rod 18: Grinding wheel 20,22: Container

Claims

1. 1. A grinding wheel for grinding a workpiece, comprising: A wheel base having an annular groove formed on one surface thereof; a plurality of grindstones each inserted into the groove and protruding from the one surface; and an adhesive for fixing the plurality of grinding wheels in the grooves; The grindstone has a bond material containing a phenolic resin that releases ammonia gas, and abrasive grains dispersed in the bond material, The adhesive has an adsorbent dispersed therein for adsorbing the ammonia gas.

2. 2. The grinding wheel of claim 1, wherein the adsorbent comprises at least one of zeolite, silica gel, or activated carbon.

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