JP7599780B2 - Dressing Tools - Google Patents

Description

The present invention relates to a dressing tool equipped with a dressing board for dressing a grinding wheel.

Chips of devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are essential components in various electronic devices such as mobile phones and personal computers. These chips are manufactured, for example, by thinning a wafer on which many devices are formed and then dividing it into areas containing individual devices.

One method for thinning the wafer is, for example, grinding using a grinding device that has a grinding wheel with multiple grinding stones arranged in a circular pattern and a chuck table that holds the front side of the wafer by suction.

In this grinding device, the grinding wheel and the chuck table are rotated while the grinding surface of the grinding wheel and the back surface of the wafer are brought into contact with each other while water or the like is supplied to the grinding surface of the grinding wheel and the back surface of the wafer (see, for example, Patent Document 1). As a result, the back surface of the wafer is ground by the grinding surface of the grinding wheel, thinning the wafer.

The grinding wheel has a bond material, such as a vitrified bond or resin bond, that has pores inside, and abrasive grains, such as diamond or cubic boron nitride (cBN), dispersed in the bond material. The wafer is then ground by the abrasive grains exposed on the grinding surface of the grinding wheel.

However, in unused grinding wheels, the abrasive grains may not be fully exposed on the grinding surface of the grinding wheel. Also, the grinding surfaces of the multiple grinding wheels included in the grinding wheel may not be located on the same plane.

Furthermore, if grinding debris produced by grinding adheres to the grinding surface of the grinding wheel, the abrasive grains may not be fully exposed on the grinding surface of the grinding wheel (the grains may become clogged). Also, repeated grinding may cause the abrasive grains exposed on the grinding surface to wear out (the grains may become worn down).

In these cases, the grinding efficiency of the grinding device may decrease. For this reason, grinding devices often perform a process (dressing) at appropriate times to grind the grinding surfaces of multiple grinding wheels to prepare them in a condition suitable for grinding.

This type of dressing is performed, for example, by contacting the grinding surface of the grinding wheel with a dressing board of a dressing tool that is held by suction on a chuck table while rotating the grinding wheel (see, for example, Patent Document 2).

JP 2014-124690 A JP 2009-142906 A

When a grinding wheel is dressed, the side of the dressing board that comes into contact with the grinding wheel is also worn down. Therefore, repeated dressing of the grinding wheel reduces the thickness of the dressing board.

If the dressing of the grinding wheel is performed without changing conditions such as the distance between the chuck table and the grinding wheel, even though the thickness of the dressing board has been reduced, the grinding surface side of the grinding wheel will not be sufficiently ground. In other words, in this case, the grinding wheel will not be properly dressed.

To properly dress a grinding wheel, it is necessary to know the thickness of the dressing tool, including the dressing board, in advance. Therefore, dressing of the grinding wheel is often performed after the thickness of the dressing tool, including the dressing board, has been measured.

In view of this, the object of the present invention is to provide a dressing tool that allows the thickness of the dressing tool to be ascertained without measuring the thickness of the dressing tool in order to simplify the dressing of a grinding wheel.

According to one aspect of the present invention, a dressing tool is provided, comprising a dressing board for dressing a grinding wheel and a support plate to which the dressing board is fixed on an upper surface, wherein a plurality of grooves, each of differing depths, are formed on the upper surface side of the dressing board , and the upper surface of the support plate includes a plurality of locations at which information relating to the depth of each of the plurality of grooves is displayed in a visibly visible manner, and each of the plurality of locations displays information relating to the depth of the nearest groove among the plurality of grooves.

In the present invention, multiple grooves of different depths are formed on the upper surface of the dressing board. As a result, when the upper surface of the dressing board is scraped off by dressing with the grinding wheel and the thickness of the dressing board is reduced, the shallow grooves are lost and the number of multiple grooves formed on the upper surface of the dressing board is reduced.

Therefore, in the present invention, by visually checking the top surface of the dressing board and identifying the number of remaining grooves, the thickness of the dressing tool can be ascertained without actually measuring the thickness of the dressing tool. As a result, dressing of the grinding wheel is simplified.

FIG. 1A is a plan view that shows a schematic diagram of an example of a dressing tool, and FIG. 1B is a front view that shows a schematic diagram of an example of a dressing tool. FIG. 2 is a perspective view illustrating an example of a grinding apparatus. FIG. 3 is a plan view showing a schematic example of a dressing tool used for dressing a grinding wheel.

An embodiment of the present invention will be described with reference to the attached drawings. FIG. 1(A) is a plan view showing an example of a dressing tool, and FIG. 1(B) is a front view showing an example of a dressing tool.

The dressing tool 2 shown in Figures 1(A) and 1(B) comprises a disk-shaped dressing board 4 having parallel circular upper and lower surfaces, and a disk-shaped support plate 6 having parallel upper and lower surfaces, with the dressing board 4 fixed to its upper surface.

The dressing board 4 and the support plate 6 are fixed so that the center of the underside of the dressing board 4 and the center of the upper side of the support plate are in contact. The diameters of the upper and lower sides of the dressing board 4 are shorter than the diameters of the upper and lower sides of the support plate 6.

The dressing board 4 is formed by kneading, for example, green carborundum (GC) abrasive grains made of silicon carbide (SiC) or white alundum (WA) abrasive grains made of aluminum oxide ( _Al2O3 ) with a binder made of a vitrified bond or a resin bond, and then firing the mixture _. The support plate 6 is made of, for example, polyvinyl chloride or the like.

Furthermore, on the upper surface side of the dressing board 4, a plurality of grooves 8 (30 grooves as an example in Figures 1 (A) and 1 (B)) are formed, each having a different depth from the upper surface (each height from the lower surface). Each of the plurality of grooves 8 extends from the outer edge of the dressing board 4 along the radial direction of the upper surface or lower surface of the dressing board 4.

The length of each of the grooves 8 along the direction is approximately equal and shorter than the radius of the upper and lower surfaces of the dressing board 4. The grooves 8 are also arranged at approximately equal intervals along the circumferential direction of the dressing board 4.

More specifically, the dressing board 4 shown in Figures 1(A) and 1(B) has a thickness of 1100 μm, and the support plate 6 has a thickness of 1000 μm. The upper surface of the dressing board 4 is provided with a groove 8a having a depth of 30 μm, a groove 8b having a depth of 900 μm adjacent to the groove 8a, and 28 grooves with a difference in depth between adjacent grooves of 30 μm.

Therefore, for example, groove 8a having a depth of 30 μm and groove 8c having a depth of 480 μm, which is included in the 28 grooves, are arranged in a position that is point-symmetrical with respect to the center point of the upper surface of the dressing board 4 in a planar view. Similarly, groove 8b having a depth of 900 μm and groove 8d having a depth of 450 μm, which is included in the 28 grooves, are arranged in a position that is point-symmetrical with respect to the center point of the upper surface of the dressing board 4 in a planar view.

The upper surface of the support plate 6 also includes a plurality of locations 10 at which information regarding the depth of the plurality of grooves 8 is displayed in a visible manner. Each of the plurality of locations 10 displays information regarding the depth of the groove 8 that is closest to the other of the plurality of grooves 8.

More specifically, the upper surface of the support plate 6 shown in Figures 1(A) and 1(B) includes 30 locations 10 at which information regarding the depth of the 30 grooves 8 is displayed in a visible manner. The 30 locations 10 are located outside the dressing board 4 and are arranged at approximately equal intervals along the circumferential direction of the dressing board 4. In addition, each of the 30 locations 10 displays the distance between the bottom surface of the groove 8 and the underside of the support plate 6 as information regarding the depth of the closest groove 8 among the 30 grooves 8.

For example, at point 10a closest to groove 8a with a depth of 30 μm, the distance between the bottom surface of groove 8a and the underside of support plate 6 is shown to be (1100 μm (thickness of dressing board) + 1000 μm (thickness of support plate) - 30 μm = 2070 μm). Similarly, at point 10b closest to groove 8b with a depth of 900 μm, the distance between the bottom surface of groove 8b and the underside of support plate 6 is shown to be (1100 μm + 1000 μm - 900 μm = 1200 μm).

The grooves 8 are formed, for example, by cutting the dressing board 4 using a known cutting device. Information regarding the depth of the grooves 8, such as the distance between each of the grooves 8 and the underside of the support plate 6, is printed, for example, by processing the multiple locations 10 of the support plate 6 using a known laser processing device.

Figure 2 is a perspective view showing a schematic example of a grinding device that uses a dressing tool 2 to dress a grinding wheel. The grinding device 12 shown in Figure 2 has a chuck table 14 that can hold a workpiece such as a wafer or the dressing tool 2. The chuck table 14 has a disk-shaped frame 16 made of, for example, ceramics.

A recess with a circular opening at the top end is formed on the top surface of the frame 16, and a disk-shaped porous plate 18 made of ceramics or the like is fixed in this recess. The top surface of the porous plate 18 is configured in a shape equivalent to the side of a cone whose center protrudes slightly beyond the outer edge, and the workpiece or dressing tool 2 is placed on this top surface.

The lower surface of the porous plate 18 is connected to a suction source (not shown) such as an ejector via a flow path (not shown) and a valve (not shown) provided inside the frame 16. Therefore, when the suction source is operated with the valve open, the workpiece or dressing tool 2 placed on the upper surface of the porous plate 18 is sucked by the chuck table 14.

Furthermore, the chuck table 14 is connected to a horizontal movement mechanism (not shown). The horizontal movement mechanism has, for example, a ball screw and a motor. When the horizontal movement mechanism operates, the chuck table 14 moves in the horizontal direction.

The chuck table 14 is also connected to a rotation mechanism (not shown). The rotation mechanism includes, for example, a spindle and a motor. When the rotation mechanism operates, the chuck table 14 rotates in the direction of arrow a shown in FIG. 2, with a rotation axis that passes through the center of the holding surface and is aligned vertically or slightly inclined relative to the vertical.

A grinding unit 20 is provided above the chuck table 14. The grinding unit 20 has a spindle 22 whose upper end is connected to a rotational drive source such as a motor. A disk-shaped wheel mount 24 is fixed to the lower end of the spindle 22.

The wheel mount 24 has a number of openings (not shown) that penetrate the wheel mount 24 in the thickness direction. The openings are arranged at approximately equal intervals along the circumferential direction of the wheel mount 24. A bolt 26 is inserted into each of the openings.

A grinding wheel 28 is attached to the bottom of the wheel mount 24. Specifically, the grinding wheel 28 has an annular base 30. The top of the base 30 is provided with multiple female threads (not shown), and the lower ends of the bolts 26 are screwed into each female thread, thereby attaching the grinding wheel 28 to the bottom of the wheel mount 24.

Furthermore, a plurality of grinding wheels 32 are fixed to the lower end of the base 30 and are arranged at approximately equal intervals along the circumferential direction of the base 30. The lower surfaces of the grinding wheels 32 are arranged at approximately the same height, and these lower surfaces become the grinding surfaces of the grinding unit 20.

Furthermore, the spindle 22 is connected to a vertical movement mechanism (not shown). The vertical movement mechanism has, for example, a ball screw and a motor. When the vertical movement mechanism operates, the spindle 22, the wheel mount 24, and the grinding wheel 28 move in the vertical direction.

The spindle 22 is also connected to a rotary drive source (not shown) such as a motor. When the rotary drive source operates, the spindle 22 rotates in the direction of arrow b shown in FIG. 2, with a straight line passing through the center of the spindle 22 along the vertical direction as its rotation axis.

Dressing of the grinding wheel 32 in the grinding device 12 is performed, for example, in the following order: First, the operator visually checks the dressing tool 2 to determine the thickness of the dressing tool 2.

For example, as shown in FIG. 3, if 9 of the 30 grooves 8 on the top surface of the dressing board 4 cannot be seen and 21 grooves 8 can be seen, the operator can determine that the thickness of the dressing tool 2 is greater than 1800 μm and less than or equal to 1830 μm.

Next, with the chuck table 14 and the grinding unit 20 separated in both the horizontal and vertical directions, the dressing tool 2 is placed on the holding surface of the chuck table 14 with the dressing board 4 facing upward.

Next, the suction mechanism operates so that the dressing tool 2 is sucked and held on the chuck table 14. Next, the horizontal movement mechanism moves the chuck table 14 so that the rotation axis of the chuck table 14 overlaps with the annular area in which the multiple grinding wheels 32 are arranged.

Then, the rotation mechanism rotates the chuck table 14, and the motor connected to the upper end of the spindle 22 rotates the spindle 22, the wheel mount 24, and the grinding wheel 28.

Then, taking into account the thickness of the dressing tool 2, the vertical movement mechanism lowers the spindle 22, the wheel mount 24, and the grinding wheel 28 to a position where the grinding wheel 32 can be appropriately dressed. This dresses the grinding wheel 32.

As described above, in the dressing tool 2, multiple grooves 8 of different depths are formed on the upper surface side of the dressing board 4. As a result, when the upper surface side of the dressing board 4 is scraped by dressing with the grinding wheel 32 and the thickness of the dressing board 4 is reduced, shallow grooves (such as groove 8a with a depth of 30 μm) are lost and the number of multiple grooves 8 formed on the upper surface side of the dressing board 4 is reduced.

Therefore, in the dressing tool 2, the thickness of the dressing tool 2 can be grasped by visually checking the upper surface side of the dressing board 4 and recognizing the number of remaining grooves 8, without actually measuring the thickness of the dressing tool 2. In other words, the dressing of the grinding wheel 32 can be simplified.

Furthermore, in the dressing tool 2, the upper surface of the support plate 6 includes a plurality of locations 10 where information regarding the depth of the plurality of grooves 8 (the distance between the bottom surfaces of the plurality of grooves 8 and the lower surface of the support plate 6) is displayed in a visible manner. This allows the thickness of the dressing tool 2 to be easily grasped.

The dressing tool 2 is one aspect of the present invention, and the dressing tool of the present invention is not limited to the dressing tool 2. For example, the support plate 6 does not have to include multiple locations 10. In other words, the support plate 6 does not have to display information regarding the depth of the multiple grooves 8 in a visible manner.

The grooves 8 do not have to extend along the radial direction of the dressing board 4, and may be formed so that all of the grooves 8 are parallel to each other, for example. The thickness of the dressing board 4 is not limited to 1100 μm, and the thickness of the support plate 6 is not limited to 1000 μm.

The number of grooves 8 formed on the upper surface side of the dressing board 4 is not limited to 30. The difference in depth between adjacent pairs of grooves 8 (excluding adjacent grooves 8a and 8b) is not limited to 30 μm.

In addition, the information regarding the depth of each of the multiple grooves 8 shown at the multiple locations 10 on the upper surface of the support plate 6 is not limited to the distance between the bottom surface of the groove 8 and the lower surface of the support plate 6. For example, the depth of each of the multiple grooves 8 may be shown at the multiple locations 10.

In addition, the structures and methods of the above-described embodiments and variations can be modified as appropriate without departing from the scope of the present invention.

2: Dressing tool 4: Dressing board 6: Support plate 8 (8a, 8b, 8c, 8d): Groove 10 (10a, 10b): Location 12: Grinding device 14: Chuck table 16: Frame 18: Porous plate 20: Grinding unit 22: Spindle 24: Wheel mount 26: Bolt 28: Grinding wheel 30: Base 32: Grinding stone

Claims (1)

a dressing board for dressing the grinding wheel;
A support plate having an upper surface on which the dressing board is fixed,
A plurality of grooves having different depths are formed on the upper surface of the dressing board,
the upper surface of the support plate includes a plurality of locations at which information regarding the depth of each of the plurality of grooves is visibly indicated;
A dressing tool, characterized in that each of the plurality of locations indicates information regarding the depth of a nearest adjacent one of the plurality of grooves.

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