grinding wheel

Abstract

To provide a grinding wheel facilitating easy confirmation of a state inside the grinding wheel during grinding a workpiece.SOLUTION: The grinding wheel for grinding a workpiece includes: an annular wheel base; and a plurality of grinding stones provided on one surface of the wheel base; wherein the wheel base is made of a transparent material. The grinding wheel is characterized in that the wheel base is made of a transparent material, which, when this grinding wheel is used, facilitates confirmation of a state inside the grinding wheel during grinding a workpiece, for example, an amount of a grinding fluid supplied to a grinding point.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[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 dividing a workpiece such as a wafer having a plurality of devices formed on the surface side along the boundaries of the plurality of devices.

[0003] Furthermore, the workpiece is often thinned before being divided for the purpose of miniaturization and weight reduction of the chip. As a method of thinning the workpiece, grinding of the back surface side of the workpiece by a grinding device can be mentioned. The grinding device generally includes a chuck table for holding the surface side of the workpiece and a spindle provided above the chuck table and having a grinding wheel mounted at the lower end.

[0004] The grinding wheel generally includes an annular wheel base having a surface on which an annular groove is formed, and a plurality of grinding wheels each having one end fixed in the groove. Furthermore, a flow path for supplying a grinding fluid such as pure water to the contact interface (processing point) between the plurality of grinding wheels and the workpiece may be formed inside the grinding wheel (see, for example, Patent Document 1).

[0005] In the grinding device, for example, while the grinding fluid is supplied to the back surface of the workpiece in a state where both the chuck table holding the surface side of the workpiece and the grinding wheel mounted at the lower end of the spindle are rotating, the plurality of grinding wheels are brought into contact with the back surface of the workpiece. As a result, the back surface side of the workpiece is ground in a state where the grinding fluid is supplied to the processing point, and the workpiece is thinned.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-124690 [Overview of the project] [Problems that the invention aims to solve]

[0007] The wheel base of a grinding wheel is generally made of a metal material such as aluminum. Therefore, it is difficult to check the condition of the inside of the grinding wheel, for example, the amount of grinding fluid supplied to the processing point, while grinding a workpiece. In view of this, the present invention aims to provide a grinding wheel that makes it easy to check the condition of the inside of the grinding wheel while grinding a workpiece. [Means for solving the problem]

[0008] According to the present invention, a grinding wheel for grinding a workpiece comprises an annular wheel base including one surface, an opposite surface which is the back surface of the one surface, and an inner surface and an outer surface connecting the one surface and the opposite surface, and a plurality of grinding wheels provided on one surface of the wheel base, wherein the wheel base is made of a transparent material. The inner surface includes a first inclined portion, and the outer surface includes a second inclined portion parallel to the first inclined portion in a longitudinal cross-section, and the grinding surfaces of the plurality of grinding wheels are located on the same plane. A grinding wheel is provided.

[0009] Furthermore, in the present invention, it is preferable that a metal layer is provided on the opposite surface.

[0010] Furthermore, in the present invention, it is preferable that a screw hole for screwing a bolt is formed on the opposite surface, and that the side wall of the screw hole is made of a metal material. [Effects of the Invention]

[0012] In the grinding wheel of the present invention, the wheel base is made of a transparent material. Therefore, when using this grinding wheel, it becomes easy to check the condition of the inside of the grinding wheel while grinding the workpiece, for example, the amount of grinding fluid supplied to the processing point. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1(A) is a schematic top view showing an example of a grinding wheel, Figure 1(B) is a schematic cross-sectional view showing an example of a grinding wheel, and Figure 1(C) is a schematic bottom view showing an example of a grinding wheel. [Figure 2] Figure 2 is a schematic cross-sectional side view showing how a workpiece is ground in a grinding machine. [Figure 3] Figure 3 is a schematic cross-sectional view showing another example of a grinding wheel. [Figure 4] Figure 4 is a schematic cross-sectional view showing yet another example of a grinding wheel. [Figure 5] Figure 5 is a schematic cross-sectional view showing yet another example of a grinding wheel. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described with reference to the attached drawings. Figure 1(A) is a schematic top view showing an example of a grinding wheel, Figure 1(B) is a schematic cross-sectional view showing an example of a grinding wheel, and Figure 1(C) is a schematic bottom view showing an example of a grinding wheel.

[0015] The grinding wheel 2 shown in Figures 1(A), 1(B), and 1(C) has an annular wheel base 4 made of a transparent material. Examples of transparent materials include acrylic resin or transparent ceramics.

[0016] The wheel base 4 has a generally flat upper surface (opposite 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 upper surface 4a. The upper surface 4a and the lower surface 4b are connected via an inner surface 4c and an outer surface 4d.

[0017] The inner surface 4c includes an inclined portion with a shape corresponding to the side surface of a frustocone. The outer surface 4d has a shape corresponding to the side surface of a cylinder. Furthermore, the upper surface 4a has a plurality of screw holes 4e formed at approximately equal angular intervals along the circumferential direction of the wheel base 4.

[0018] Then, the grinding wheel 2 is mounted on the tip (lower end) of the spindle provided in the grinding device by using bolts screwed into each of the plurality of screw holes 4e. Further, an annular groove 4f having a rectangular cross section is formed in the lower surface 4b of the wheel base 4.

[0019] The width of this groove 4f (the length along the radial direction of the wheel base 4) is, for example, 2.0 mm to 5.0 mm, and its depth is, for example, 2 mm. And a plurality of upper end sides (one end sides) of the grinding wheels 6 are inserted into this groove 4f at substantially equal angular intervals along the circumferential direction of the wheel base 4.

[0020] The grinding wheel 6 has a shape obtained by curving a rectangular parallelepiped with a curvature substantially equal to that of the groove 4f. Further, the grinding wheel 6 includes a binder such as vitrified or resinoid, and abrasive grains such as diamond dispersed in this binder. Also, the width of the grinding wheel 6 (the length along the radial direction of the wheel base 4) is, for example, 1.6 mm to 4.0 mm.

[0021] Furthermore, the lower end surfaces (grinding surfaces) of the plurality of grinding wheels 6 are located on substantially the same plane. Also, the plurality of grinding wheels 6 are fixed to the groove 4f via a cured adhesive 8. The cured adhesive 8 is obtained, for example, by drying a highly viscous liquid adhesive mainly composed of a resin.

[0022] This liquid adhesive is adjusted to have a viscosity such that it does not drip downward from the groove 4f in a state where the groove 4f faces downward, and it holds the plurality of grinding wheels 6 without dropping them when the upper end sides of the plurality of grinding wheels 6 are inserted into the groove 4f in this state.

[0023] For example, the viscosity of this liquid adhesive at room temperature is 20 Pa·S to 100 Pa·S. Also, this liquid adhesive may contain a filler for increasing viscosity. Examples of the material of this filler include materials mainly composed of alumina (Al2O3) such as white alumina (WA).

[0024] Figure 2 is a schematic cross-sectional side view illustrating the grinding process of a workpiece in a grinding apparatus equipped with a spindle to which a grinding wheel 2 is mounted at its tip (lower end). For convenience, the operator's line of sight is indicated by an arrow in Figure 2.

[0025] The grinding apparatus 10 shown in Figure 2 has a chuck table 12 capable of holding a workpiece 11. The chuck table 12 has a disc-shaped frame 14 made of, for example, ceramics. This frame 14 has a disc-shaped bottom wall 14a and cylindrical side walls 14b that rise from the outer circumference of the bottom wall 14a.

[0026] Specifically, a disc-shaped recess is formed on the upper surface of the frame 14, defined by the bottom wall 14a and the side walls 14b. A disc-shaped porous plate 16 made of porous ceramics or the like is fixed in this recess.

[0027] Furthermore, the upper surfaces of the side walls 14b of the frame 14 and the upper surface of the porous plate 16 have a shape corresponding to the side surface of a cone and function as holding surfaces for the chuck table 12. In addition, a flow channel 14c is formed in the bottom wall 14a, which opens at the bottom surface of the recess and penetrates the bottom wall 14a.

[0028] Furthermore, the flow path 14c is connected to a suction source (not shown), such as an ejector, via a valve or the like. When the suction source operates with the workpiece 11 placed on the holding surface of the chuck table 12, the workpiece 11 is sucked in and held in place by the chuck table 12.

[0029] Furthermore, the chuck table 12 is connected to a rotating mechanism (not shown) that includes a servo motor and pulleys. When this rotating mechanism operates, the chuck table 12 rotates around a straight line passing through the center of the holding surface of the chuck table 12 as the axis of rotation.

[0030] Furthermore, the chuck table 12 is connected to a tilt adjustment mechanism (not shown). This tilt adjustment mechanism includes two movable axes and one fixed axis, which are arranged at approximately equal angular intervals along the circumferential direction of the chuck table 12. When at least one of the two movable axes partially raises or lowers the chuck table 12, the tilt of the rotation axis of the chuck table 12 is adjusted.

[0031] Above the chuck table 12, a spindle 18 is provided, to which a servo motor (not shown) is connected at its base end (upper end). When this servo motor operates, the spindle rotates around a straight line along the direction in which the spindle 18 extends as its axis of rotation. The tip (lower end) of the spindle 18 has a disc-shaped form with a diameter approximately equal to the outer diameter of the grinding wheel 2, and functions as a mount 20 on which the grinding wheel 2 is attached.

[0032] Furthermore, multiple through holes (not shown) are formed on the outer circumference of the mount 20 at intervals that are approximately equal in angle to the multiple screw holes 4e formed on the upper surface 4a of the wheel base 4. The grinding wheel 2 is then attached to the mount 20 by inserting bolts 22 into each through hole and screwing each bolt 22 into the screw holes 4e.

[0033] A grinding fluid supply unit 24 is provided below the grinding wheel 2. This grinding fluid supply unit 24 includes, for example, a nozzle 26 located inside the grinding wheel 2 in a plan view, and a pump (not shown) that supplies a liquid (grinding fluid) such as pure water to the nozzle 26.

[0034] When this pump operates, grinding fluid is supplied from the nozzle 26 to the upper surface of the workpiece 11 held by the chuck table 12. In the grinding apparatus 10, grinding fluid may also be supplied via a flow path formed in the grinding wheel 2 instead of or in addition to the nozzle 26.

[0035] Furthermore, the spindle 18 is connected to a lifting mechanism (not shown) that includes a ball screw and a stepping motor. When this lifting mechanism operates, the spindle 18, mount 20, and grinding wheel 2 move up and down.

[0036] When grinding the upper surface of the workpiece 11 using the chuck table 12, first, the rotation mechanism connected to the chuck table 12 and the servo motor connected to the base end of the spindle 18 are operated to rotate both the chuck table 12 and the grinding wheel 2.

[0037] Next, while both the chuck table 12 and the grinding wheel 2 are rotating, the lifting mechanism connected to the spindle 18 is operated to bring the multiple grinding wheels 6 into contact with the workpiece 11. That is, while both the chuck table 12 and the grinding wheel 2 are rotating, the grinding wheel 2 is lowered until the workpiece 11 and the multiple grinding wheels 6 come into contact.

[0038] Furthermore, the grinding fluid supply unit 24 is operated so that grinding fluid L is supplied to the workpiece 11 just before it comes into contact with the multiple grinding wheels 6. As a result, the upper surface of the workpiece 11 is ground while grinding fluid L is supplied to the contact interface (machining point) between the workpiece 11 and the multiple grinding wheels 6.

[0039] In this grinding wheel 2, the wheel base 4 is made of a transparent material. Therefore, when using this grinding wheel 2, it becomes easy to check the condition of the inside of the grinding wheel 2 while grinding the workpiece 11, for example, the amount of grinding fluid L supplied to the processing point.

[0040] Note that the grinding wheel 2 is one embodiment of the present invention, and the content of the present invention is not limited to the grinding wheel 2. Figures 3 to 5 are schematic cross-sectional views showing another example of the grinding wheel of the present invention. In Figure 5, for convenience, the operator's line of sight is indicated by an arrow.

[0041] The grinding wheel 28 shown in Figure 3 has the same structure as the grinding wheel 2, except that an annular metal layer 30 is provided on the upper surface 4a of the wheel base 4. This metal layer 30 is made of a metal material with higher strength than the wheel base 4. In addition, multiple through holes (not shown) are formed on the outer circumference of the metal layer 30 so as to overlap with multiple screw holes 4e formed on the upper surface 4a of the wheel base 4.

[0042] Because this metal layer 30 is stronger than the wheel base 4, burrs are less likely to form on the upper surface of the grinding wheel 28 (the upper surface of the metal layer 30) than on the upper surface of the grinding wheel 2 (the upper surface 4a of the wheel base 4). Therefore, when the grinding wheel 28 is mounted on the tip (lower end) of the spindle 18, malfunctions are less likely to occur compared to when the grinding wheel 2 is mounted.

[0043] The grinding wheel 32 shown in Figure 4 has the same structure as the grinding wheel 2, except that the side wall 34 defining the screw hole 4e formed on the upper surface 4a of the wheel base 4 is embedded on the upper surface 4a side of the wheel base 4. This side wall 34 is made of a metal material with higher strength than the wheel base 4.

[0044] Because the side wall 34 is stronger than the wheel base 4, in the grinding wheel 32, compared to the grinding wheels 2 and 28, the bolts 22 are less likely to separate from the wheel base 4 even when strong forces are applied to the bolts 22 during grinding of the workpiece 11. Therefore, when grinding of the workpiece 11 is performed using the grinding wheel 32, problems are less likely to occur compared to when grinding is performed using the grinding wheels 2 and 28.

[0045] The grinding wheel 36 shown in Figure 5 has the same structure as the grinding wheel 2, except that the outer surface 4g of the wheel base 4 includes an inclined portion (second inclined portion) parallel to the inclined portion (first inclined portion) included in the inner surface 4c in a longitudinal cross-section.

[0046] In the case of the grinding wheel 36, the width of the wheel base in the direction of the operator's line of sight tends to be constant. Therefore, when the grinding wheel 36 is mounted on the tip (lower end) of the spindle 18, it becomes easier to check the inside compared to when the grinding wheels 2, 28, or 32 are mounted.

[0047] Furthermore, the structures and methods of the embodiments described above can be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0048] 2: Grinding Wheel 4: Wheel base (4a: top surface (opposite surface), 4b: bottom surface (one side), 4c inner surface) (4d: outer surface, 4e: screw hole, 4f: groove, 4g: outer surface) 6: Grinding Wheel 8: Adhesive 10: Grinding equipment 12: Chuck Table 14: Frame (14a: bottom wall, 14b: side wall, 14c: flow channel) 16: Porous plate 18: Spindle 20: Mount 22: Bolt 24: Grinding fluid supply unit 26: Nozzle 28: Grinding Wheel 30: Metal layer 32: Grinding Wheel 34: Side wall 36: Grinding Wheel

Claims

1. A grinding wheel for grinding a workpiece, An annular wheel base including one surface, the opposite surface which is the back surface of the one surface, and an inner surface and an outer surface connecting the one surface and the opposite surface, It comprises a plurality of grinding wheels provided on one surface, The wheel base is made of a transparent material. The inner surface includes a first inclined portion, The outer surface includes a second inclined portion parallel to the first inclined portion in a longitudinal cross-section, The grinding surfaces of the multiple grinding wheels are located on the same plane.

2. The grinding wheel according to claim 1, wherein a metal layer is provided on the opposite surface.

3. On the opposite side, a screw hole is formed for screwing in a bolt. The grinding wheel according to claim 1, wherein the side wall of the screw hole is made of a metal material.

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