JP2003181767A - Mechanism for mounting grinding wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve accurate grinding operation by making a rotary axis of a grinding wheel coincide with a rotary axis of a mount, when a platelike workpiece is ground by a grinding stone provided on the grinding wheel mounted on the mount formed at the tip end portion of a spindle so as to rotate by rotation of the spindle. <P>SOLUTION: The grinding wheel 20 is configured such that the grinding stone 22 is fixed on a free annular portion 24 of a ringlike base 21 having a fixing annular portion 23, the free annular portion 24, an outer wall 26 and an inner wall 25, which are elongated from the fixing annular portion 23 to the free annular portion 24. The mount 19 has a fixing annular portion supporting portion 30 for supporting the fixing annular portion 23 and an inner wall supporting portion 29 for supporting the inner wall 25. The ringlike base 21 is constructed by such a member that the diameter of the inner wall 25 is changed by temperature change. At ordinary temperature, the diameter D2 of the inner wall 25 is formed to be smaller than the diameter D1 of the inner wall supporting portion 29. In the mechanism for mounting the grinding wheel 20, the ringlike base 21 is mounted on the mount 19 in such a state that the diameter D2 of the inner wall 25 has become larger than the diameter D1 of the inner wall supporting portion 29 by heating the ringlike base 21. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding wheel mounting mechanism equipped with a grindstone used for grinding a plate-like object such as a semiconductor wafer and mounted on a mounter formed at the tip of a spindle of a grinding machine.

[0002]

2. Description of the Related Art A semiconductor wafer having a plurality of circuits such as ICs and LSIs formed on the front surface is processed into a predetermined thickness by grinding the back surface, and then divided into individual semiconductor chips to form various semiconductor chips. Is used in electronic devices. Particularly in recent years, the thickness of semiconductor wafers has been reduced to 1 in order to meet the needs for downsizing, thinning, and weight reduction of mobile phones and the like.
There is an urgent need to reduce the thickness to about 00 μm to 50 μm.

When grinding the back surface of a semiconductor wafer, a grinding device 40 as shown in FIG. 5 is used. This grinding device 4
0 is equipped with a spindle unit 44 having a spindle 41 having a vertical rotation axis, a mounter 42 formed at the lower end of the spindle 41, and a grinding wheel 43 mounted on the mounter 42. The semiconductor wafer W is held face down on the chuck table 45 and the spindle unit 44 is
The back surface of the semiconductor wafer W is ground by bringing the grindstone 46 fixed to the lower part of the grinding wheel 43 into contact with the back surface of the semiconductor wafer W while rotating it at a rotation speed of about RPM and lowering it.

[0004]

However, in some cases, the grinding wheel 43 and the mounter 42 are mounted in a state where the center of rotation of the grinding wheel 43 and the center of rotation of the mounter 42 are slightly deviated from each other. In this case, the rotational balance of the rotating shaft is lost. There is a problem that slight vibration occurs in the grinding wheel 43, the back surface of the semiconductor wafer W cannot be ground with high accuracy, and the quality of the semiconductor wafer W deteriorates.

Therefore, in the grinding performed as described above, there is a problem in mounting the grinding wheel on the mounter so that the rotation center of the grinding wheel and the rotation center of the mounter coincide with each other.

[0006]

As a concrete means for solving the above problems, the present invention provides a grinding wheel mounting mechanism for mounting a grinding wheel on a mounter formed at the tip of a rotatable spindle. Then, the grinding wheel has a structure in which a grindstone is fixed to a free annular portion of a ring-shaped base composed of a fixed annular portion, a free annular portion, and an outer ring wall and an inner ring wall extending from the fixed annular portion to the free annular portion. The mounter has a fixed annular portion support portion that supports the fixed annular portion,
The inner ring wall support portion that supports the inner ring wall is provided, and the ring-shaped base is composed of a member whose diameter changes with the temperature change, and the inner ring wall diameter is smaller than the diameter of the inner ring wall support portion at room temperature. Provided is a grinding wheel mounting mechanism which is formed and mounted on a mounter in a state where the diameter of the inner ring wall is larger than the diameter of the inner ring wall support portion due to heating.

In this grinding wheel mounting mechanism, the diameter of the inner ring wall is 0.1 μm to 10 μm smaller than the diameter of the inner ring wall supporting portion.
An additional requirement is that it be formed small in the μm range.

In the grinding wheel mounting mechanism thus constructed, the diameter of the inner ring wall of the grinding wheel is formed to be slightly smaller than the diameter of the inner ring wall support portion of the mounter at room temperature, and the grinding wheel is mounted. When mounting on the inner ring wall, the diameter of the inner ring wall is expanded and mounted on the mounter so that the inner ring wall tightens the inner ring wall support when the temperature returns to room temperature. By closely adhering with each other, the center of rotation of the mounter and the center of rotation of the grinding wheel coincide with each other, the rotation balance is not disturbed, and fine vibration does not occur in the grinding wheel.

[0009]

FIG. 1 is a block diagram of an embodiment of the present invention.
A mounting mechanism of the grinding wheel 20 in the grinding device 10 shown in will be described.

In the grinding device 10 of FIG. 1, the base 11
A wall 12 is erected from the end of the wall 12. A pair of rails 13 is vertically arranged on the inner surface of the wall 12, and a support 14 moves up and down along the rail 13. Accordingly, the grinding means 15 attached to the support portion 14 is configured to move up and down. Also, on the base 11,
A turntable 16 is rotatably arranged, and the turntable 16 rotatably supports a plurality of chuck tables 17 holding semiconductor wafers.

In the grinding means 15, a mounter 19 is formed at the tip of a spindle 18 having a vertical axis, and a grinding wheel 20 to which a grindstone 22 is fixed is attached to the lower part thereof. , Is configured to rotate with the rotation of the spindle 18.

As shown in FIG. 2, the grinding wheel 20 is
The ring-shaped base 21 and the grindstone 22 are generally configured. The upper surface of the ring-shaped base 21 forms a fixed annular portion 23 that is fixed to the mounter 19, and the lower surface of the ring-shaped base 21 is the grindstone 2.
2 forms a free annular portion 24 to which is fixed, and
The inner peripheral surface constitutes the inner ring wall 25, and the outer peripheral surface constitutes the outer ring wall 26. The ring-shaped base 21 is made of a metal such as aluminum, which expands due to heating to expand the diameter of the inner ring wall 25.

A grinding water flow passage 27 is provided in the fixed annular portion 23 for allowing the grinding water to flow and flow out from the free annular portion 24.
Also, the mounter 19 is provided with a screw hole 28 for screwing.

On the other hand, the mounter 19 is a substantially disk-shaped member that supports the grinding wheel 20 at the lower end of the spindle 18, and the lower end of the mounter 19 has a diameter of the inner ring wall 25 of the ring-shaped base 21 as shown in FIG. Is formed, and the outer peripheral surface of the protrusion is formed on the inner ring wall support portion 29.
The bottom surface of the mounter 19 on the outer peripheral side of the protrusion constitutes the fixed annular portion support portion 30.

As shown in FIG. 4, the diameter of the inner ring wall support portion 29 constituting the mounter 19 is D1, and the grinding wheel 2
If the diameter of the inner ring wall 25 forming 0 is D2, the relationship of D1> D2 is established at room temperature. Specifically, D
2 is smaller than D1 in the range of 0.1 μm to 10 μm.

When the grinding wheel 20 is mounted on the mounter 19, the inner wheel wall 2 is warmed by warming the grinding wheel 20.
5 is expanded to increase its diameter slightly so that the relationship of D1 <D2 is established.

In this state, the opening surrounded by the inner ring wall 25 is fitted into the inner ring wall supporting part 29 of the mounter 19, and the fixed annular part supporting part 30 of the mounter 19 and the grinding wheel 20.
When the screw 32 is screwed and fixed to the screw hole 31 formed in the mounter 19 and the screw hole 28 formed in the grinding wheel 20, the grinding wheel 20 is fixed to the mounter 19. To be done.

Since the relationship of D1> D2 is established at room temperature, the inner ring wall 25 and the inner ring wall support portion 29 come into close contact with each other when the diameter of the inner ring wall 25 tries to return to the original value after mounting, and the inner ring wall 25 Tightens the inner ring wall support 29, so that the center of rotation of the mounter 19 and the center of rotation of the grinding wheel 20 match.

After the grinding wheel 20 is mounted on the mounter 19 in this manner, for example, when the back surface of the semiconductor wafer W is ground using the grinding apparatus 10 of FIG. 1, a protective tape is attached to the front surface and the back surface is attached. Semiconductor wafer W on top
Is placed on the chuck table 17 and suction-held.

Then, the semiconductor wafer W is ground 15
Positioned immediately below, the spindle 18 is rotated and the grinding means 15 is lowered. The grinding wheel 20 rotates at a high speed as the spindle 18 rotates at a high speed, and the rotating grinding wheel 22 contacts the semiconductor wafer to apply a pressing force, so that the surface thereof is ground by the grinding wheel 22.

At this time, since the inner ring wall 25 of the grinding wheel 20 and the inner ring wall supporting portion 29 of the mounter 19 are in close contact with each other so that the centers of rotation coincide with each other and the rotation balance is not lost, the grinding wheel 20 does not vibrate slightly. Therefore, the back surface of the semiconductor wafer W can be ground with high accuracy, the plane accuracy of the semiconductor wafer W is improved, and high quality can be achieved.

If the grinding wheel 20 is firmly fixed to the mounter 19 by the close contact between the inner ring wall 25 and the inner ring wall support portion 29, the fixing by the screw 32 is not always necessary.

[0023]

As described above, in the grinding wheel mounting mechanism according to the present invention, the diameter of the inner ring wall of the grinding wheel is formed to be slightly smaller than the diameter of the inner ring wall support portion of the mounter at normal temperature. When mounting the grinding wheel on the mounter, the grinding wheel is warmed to expand the diameter of the inner ring wall and mounted on the mounter. By closely contacting the inner ring wall support portion with each other, the center of rotation of the mounter and the center of rotation of the grinding wheel coincide with each other. Therefore,
Since the rotation balance is not disturbed and the grinding wheel is not slightly vibrated, the grinding accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a grinding apparatus to which the present invention is applied.

FIG. 2 is a perspective view showing an example of a grinding apparatus that constitutes the present invention.

FIG. 3 is a front view showing an example of a mounter that constitutes the present invention.

FIG. 4 is a schematic sectional view showing how a grinding wheel is mounted on a mounter.

FIG. 5 is a front view showing a grinding device using a conventional grinding wheel mounting mechanism.

[Explanation of symbols]

10 ... Grinding device 11 ... Base 12 ... Wall 13 ... Rail 14 ... Supporting part 15 ... Grinding means 16 ... Turntable 17 ... Chuck table 18 ... Spindle 19 ... Mounter 20 ... Grinding wheel 21 ... Ring base 22 ... Whetstone 23 ... Fixed annular part 24 ... Free annular part 25 ... Inner ring wall 26 ... Outer ring wall 27 ... Grinding water flow passage 28 ... screw hole 29 ... inner ring wall support 30 ... Fixed annular part support 31 ... Screw hole 32 ... Screw 40 ... Grinding device 41 ... Spindle 42 ... Mounter 43 ... Grinding wheel 44 ... Spindle unit 45 ... Chuck table 46 ... Whetstone

Claims (2)

[Claims] 1. A mounting mechanism of a grinding wheel for mounting a grinding wheel on a mounter formed at a tip portion of a rotatable spindle, the grinding wheel comprising a fixed annular portion, a free annular portion, A grindstone is fixed to the free annular portion of a ring-shaped base composed of an outer ring wall and an inner ring wall extending from the fixed annular portion to the free annular portion, and the mounter supports the fixed annular portion. The ring-shaped base includes a fixed annular portion support portion and an inner ring wall support portion that supports the inner ring wall, and the ring-shaped base is made of a member whose diameter changes with temperature change. Is smaller than the diameter of the inner ring wall support portion, and is attached to the mounter in a state where the diameter of the inner ring wall is larger than the diameter of the inner ring wall support portion due to heating. 2. The mounting mechanism for a grinding wheel according to claim 1, wherein the diameter of the inner ring wall is smaller than the diameter of the inner ring wall supporting portion in the range of 0.1 μm to 10 μm.