JP6925699B2 - Surface grinding wheel - Google Patents

Description

The present invention relates to a surface grinding wheel used when grinding a workpiece such as a wafer.

In recent years, in order to realize a compact and lightweight device chip, there are increasing opportunities to thin wafers made of materials such as silicon. In order to thin the wafer in which a device such as an IC is formed on the front surface side to a desired thickness, for example, the back surface side of the wafer may be ground. The ground wafer is divided into a plurality of device chips corresponding to each device along the planned division line.

As one of the methods for grinding a workpiece such as a wafer, an annular base and a grindstone portion in which abrasive grains are fixed by a plating layer covering the outer peripheral surface of the base are provided to provide a certain width. A method of using an annular grinding wheel (hereinafter referred to as a surface grinding wheel) is known (see, for example, Patent Document 1 and Patent Document 2). In this method, the surface grinding wheel is rotated around a rotation axis parallel to the surface to be ground of the workpiece, and the outer peripheral grindstone portion is brought into contact with the surface to be ground.

Japanese Unexamined Patent Publication No. 61-164773 JP-A-2002-192460

However, in the above-mentioned method, in principle, the pressure applied to the grindstone portion during grinding tends to increase. Therefore, if the grinding debris generated by grinding is not discharged to the outside of the surface grinding wheel or if a sufficient amount of grinding water cannot be supplied to the processing point of the grinding wheel, the abrasive grains are easily crushed and the grinding is performed. The performance could not be maintained.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a surface grinding wheel capable of easily discharging grinding debris to the outside and supplying a sufficient amount of grinding water to a machining point. Is.

According to one aspect of the present invention, the base has an annular base mounted on the spindle, 1 0Myuemu～30myuemu particle size of the abrasive grains, a 0.5 to 3 times the thickness of the particle diameter A grindstone portion fixed by a plating layer covering the outer peripheral surface of the base is provided, and a part of the abrasive grains is continuous on the outer peripheral surface of the grindstone portion along the circumferential direction of the base. the spiral grooves are exposed from the plating layer is provided, the groove is 1.5 times to 3 times the grain size of the abrasive grains, and surface grinding with a width and depth of 15μm~90μm A grindstone is provided.

In one aspect of the present invention, the groove preferably has a 1.5 to 3 times the interval of the particle size of the abrasive grains.

In the surface grinding wheel according to one aspect of the present invention, since a spiral groove continuous along the circumferential direction of the base is provided on the outer peripheral surface of the grindstone portion, the grinding debris generated by grinding the workpiece is generated. , It is discharged to the outside along the spiral groove with the rotation of the surface grinding wheel. Further, since the grinding water flows along the spiral groove with the rotation of the surface grinding wheel, a sufficient amount of grinding water can be supplied to the processing point.

It is a perspective view which shows typically the structural example of the grinding unit on which the surface grinding wheel is mounted. FIG. 2A is a cross-sectional view schematically showing a configuration example of a surface grinding wheel, and FIG. 2B is an enlarged cross-sectional view of a part of FIG. 2A.

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing a configuration example of a grinding unit on which the surface grinding wheel of the present embodiment is mounted. As shown in FIG. 1, the grinding unit 2 includes a tubular spindle housing 4 supported by a moving mechanism (not shown).

Inside the spindle housing 4, a spindle 6 having a rotation axis parallel to the front-rear direction (Y-axis direction) is housed. One end side (tip side) of the spindle 6 is exposed in front of the spindle housing 4. On the other hand, a rotary drive source (not shown) such as a motor is connected to the other end side (base end side) of the unexposed spindle 6.

A mount flange 8 is fixed to one end of the spindle 6. The mount flange 8 has a flange portion 10 that extends outward in the radial direction, and a boss portion 12 that projects forward from the central region of the flange portion 10. The surface grinding wheel 14 according to the present embodiment is mounted on the mount flange 8.

FIG. 2A is a cross-sectional view schematically showing a configuration example of the surface grinding wheel 14, and FIG. 2B is an enlarged cross-sectional view of a part of FIG. 2A. As shown in FIGS. 1, 2 (A), and 2 (B), the surface grinding wheel 14 is formed of a metal material such as stainless steel or aluminum in a disk shape (annular, cylindrical, cylindrical). It has a base 16. The base 16 has a predetermined width (thickness) in the front-rear direction.

A mounting hole 16a into which the boss portion 12 of the mount flange 8 is inserted is provided in the central portion of the base 16. The surface grinding wheel 14 can be fixed to the mount flange 8 by tightening the fixture 20 from the front end side of the boss portion 12 with the boss portion 12 of the mount flange 8 inserted into the mounting hole 16a of the base 16. That is, the surface grinding wheel 14 can be mounted on the spindle 6 via the mount flange 8.

On the outer peripheral surface 16b of the base 16 corresponding to the side surface of the cylinder, a thin spiral groove 16c continuous along the circumferential direction of the base 16 is formed. The groove 16c can be formed, for example, by processing the outer peripheral surface of the member serving as the base 16 with an NC lathe or the like. Conditions such as the width, depth, and spacing (pitch) of the groove 16c will be described later. Further, the outer peripheral surface 16b of the base 16 is provided with a grindstone portion 18 that comes into contact with a work piece (not shown) during grinding.

The grindstone portion 18 is formed, for example, by fixing the abrasive grains 24 such as diamond with a plating layer (metal layer) 22 such as nickel that covers the outer peripheral surface 16b of the base 16. The surface (outer peripheral surface) 18a exposed on the outer peripheral portion of the grindstone portion 18 is a grinding surface that comes into contact with the surface to be ground of the workpiece. There are no particular restrictions on the type (material) of the plating layer 22 and the abrasive grains 24.

The particle size of the abrasive grains 24 (for example, the maximum particle size or the average particle size) is not limited, but for example, the abrasive grains 24 having a particle size of about 10 μm to 30 μm may be used. On the other hand, the thickness of the plating layer 22 is, for example, about 0.5 to 3 times, preferably about 1 to 1.5 times the particle size of the abrasive grains 24. As a result, the abrasive grains 24 can be appropriately exposed from the plating layer 22.

The shape of the outer peripheral surface 16b of the base 16 is reflected on the surface 18a of the grindstone portion 18. That is, on the surface 18a side of the grindstone portion 18, a spiral thin groove 18b corresponding to the groove 16c of the outer peripheral surface 16b of the base 16 and continuous along the circumferential direction of the base 16 is formed. The width of the groove 18b is preferably, for example, about 1.5 to 3 times the particle size of the abrasive grains. That is, when the particle size of the abrasive grains 24 is about 10 μm to 30 μm, the width of the groove 18b may be about 15 μm to 90 μm.

The depth of the groove 18b is preferably, for example, about 1.5 to 3 times the particle size of the abrasive grains. That is, when the particle size of the abrasive grains 24 is about 10 μm to 30 μm, the depth of the groove 18b may be about 15 μm to 90 μm. Similarly, the spacing (pitch) of the grooves 18b is preferably about 1.5 to 3 times the particle size of the abrasive grains. That is, when the particle size of the abrasive grains 24 is about 10 μm to 30 μm, the spacing between the grooves 18b may be about 15 μm to 90 μm.

As described above, the shape of the surface 18a of the grindstone portion 18 is determined by the shape of the outer peripheral surface 16b of the base 16. Therefore, in order to form the grooves 18b having such a width, depth, and spacing, the width, depth, and spacing of the grooves 16c provided on the outer peripheral surface 16b of the base 16 can be set to the width and depth of the desired grooves 18b. , Just adjust to the interval.

Since the groove 18b is formed in a continuous spiral shape along the circumferential direction of the base 16, the grinding debris generated by grinding the workpiece is moved to the outside along the groove 18b with the rotation of the surface grinding wheel 14. And does not remain on the surface 18a or the like of the grindstone portion 18. Further, since the grinding water flows along the groove 18b with the rotation of the surface grinding wheel 14, a sufficient amount of grinding water can be supplied to the machining point.

A method for processing a workpiece using the surface grinding wheel 14 according to the present embodiment will be briefly described. First, a workpiece such as a wafer is fixed to a support table (not shown) located below the grinding unit 2. Here, the workpiece is fixed to the support table so that the surface to be ground is exposed upward. A substrate other than the wafer may be used as the workpiece.

Next, the spindle 6 (plane grinding wheel 14) is rotated. Further, the grinding unit 2 is lowered so that the lower end of the surface grinding wheel 14 is lower than the surface to be ground of the workpiece. The amount of descent of the grinding unit 2 is adjusted according to the amount of grinding of the workpiece (thickness of the workpiece after grinding) and the like.

In this state, by relatively moving the grinding unit 2 and the support table along the left-right direction (X-axis direction), the surface to be ground of the workpiece can be linearly ground by the surface grinding wheel 14. Grinding water such as pure water is supplied from a grinding water supply nozzle (not shown) to the processing point of the surface grinding wheel 14. The above operation is repeated while changing the positional relationship between the grinding unit 2 and the support table until the entire surface to be ground is ground.

As described above, in the surface grinding wheel 14 according to the present embodiment, the spiral groove 18b continuous along the circumferential direction of the base 16 is provided on the surface (outer peripheral surface) 18a of the grindstone portion 18. Grinding debris generated by grinding the workpiece is discharged to the outside along the spiral groove 18b as the surface grinding wheel 14 rotates. Further, since the grinding water flows along the spiral groove 18b with the rotation of the surface grinding wheel 14, a sufficient amount of grinding water can be supplied to the processing point.

The present invention is not limited to the description of the above embodiment, and can be implemented with various modifications. For example, in the above embodiment, one continuous spiral groove 18b is formed in the surface grinding wheel 14, but the present invention is not necessarily limited to this embodiment. For example, a plurality of continuous spiral grooves may be formed.

Further, in the above embodiment, the groove 18b on the surface 18a of the grindstone portion 18 is realized by forming the groove 16c on the outer peripheral surface 16b of the base 16, but the groove is formed on the outer peripheral surface 16b of the base 16. Instead, the groove 18b may be formed directly on the surface 18a of the grindstone portion 18.

In addition, the structure, method, etc. according to the above-described embodiment can be appropriately modified and implemented as long as they do not deviate from the scope of the object of the present invention.

2 Grinding unit 4 Spindle housing 6 Spindle 8 Mount flange 10 Flange part 12 Boss part 14 Flat grinding wheel 16 Base 16a Mounting hole 16b Outer peripheral surface 16c Groove 18 Grinding stone part 18a Surface (outer peripheral surface)
18b groove 20 fixture 22 plating layer (metal layer)
24 Abrasive grains

Claims (2)

A base ring which is mounted on a spindle,
Abrasive grains 1 0Myuemu～30myuemu the particle size, comprising a grinding wheel portion which is fixed by a plating layer covering the base board outer peripheral surface of a 0.5 to 3 times the thickness of the particle diameter, and
The outer peripheral surface of the grindstone portion is provided with a spiral groove that is continuous along the circumferential direction of the base and a part of the abrasive grains is exposed from the plating layer.
Groove is 1.5 times to 3 times the grain size of the abrasive grains, and a flat surface grinding wheel you characterized by having a width and depth of 15Myuemu～90myuemu. The groove, flat grinding wheel of claim 1, characterized in that it comprises 1.5 to 3 times the interval of the particle size of the abrasive grains.

Images