JPH1158234A - Polishing method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten the cooling effect of a workpiece in time of polishing by spouting gas so as to make a flow of abrasive water penetrate into a contact part between the workpiece and a polishing wheel at a time when this workpiece is polished as supplying the polishing water, and carrying the polishing work into execution. SOLUTION: When a wafer W is polished, it is mounted and held on a chuck table 33. Then, this chuck table 33 is rotated, while a polishing means 34 is making to go down as rotating an abrasive wheel 44, and a polishing wheel 48 is contacted with the wafer W. At this time, abrasive water is fed to an abrasive water supplying path 45, and this abrasive water 15 is fed to the wafer W from an abrasive water supply port 47 via a branch path 46. Simultaneously with this, gas 14 is spouted out of a nozzle 12. A flow of this abrasive water 15 increases its force, whereby it forcibly gets into a little space in the contact part between the wafer W and the polishing wheel 48. Thus, the cooling of the wafer W is yet more accelerated by the abrasive water entered like this.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method and a polishing apparatus for polishing a workpiece such as a semiconductor wafer with a polishing grindstone. The present invention relates to a polishing method for improving a polishing capability by promoting cooling of a workpiece, and a polishing apparatus used for carrying out the method.

[0002]

2. Description of the Related Art As an apparatus for polishing a surface of a semiconductor wafer or the like, a polishing apparatus 30 shown in FIG. 7 is well known as a conventional example. The polishing apparatus 30 is provided with a turntable 32 that is rotatable on a worktable 31. The plurality of rotatable chuck tables 33 provided on the turntable 32 suction-hold the wafer to hold the wafer. The wafer is polished by, and the polished wafer is transported to the cleaning area by using the transport unit, and the wafer is transported to the cassette 37 by the transport unit and stored.

A wall 38 is provided upright from an end of the work table 31, and a pair of rails 39 is provided on the inner surface of the wall 38 in a vertical direction. As the slide plate 40 moves up and down, the slide plate 4
The polishing means 34 fixed to 0 moves up and down.

[0004] As shown in FIG.
A spindle 42 is rotatably supported at the center of the spindle housing 41, a mounter 43 on a disk is mounted on a lower end of the spindle 42, and a polishing wheel 44 is mounted on a lower portion of the mounter 43. . A polishing water supply passage 45 for flowing polishing water penetrates through the spindle 42, and the polishing water supply passage 45 is connected to the mounter 4.
4 to a polishing water supply port 47 of the polishing wheel 44 via a branch path 46 in the inside. Further, the polishing water supply port 47
A polishing grindstone 48 projects downward from the outside.

When the wafer W held on the chuck table 33 is polished by the polishing means 34 configured as described above, the chuck table 33 is rotated and
The polishing means 34 is lowered while rotating the spindle 42 to press the rotating polishing grindstone 48 against the wafer W to perform polishing. At the same time, the polishing water is supplied from the upper portion of the polishing water supply passage 45, and the polishing water 49 is supplied to the wafer W from the polishing water supply port 47 via the polishing water supply passage 45 and the branch passage 46.

[0006]

However, in the above-mentioned polishing method, since the polishing water is not sufficiently supplied to the contact portion between the wafer W and the polishing grindstone 48, the cooling of the wafer W is insufficient, and the surface burns. There is a problem that
In such a situation, it is difficult to perform mirror polishing due to polishing distortion, and it is also difficult to reduce the thickness of the wafer (for example, 200 μm or less).

As described above, the conventional polishing method and the conventional polishing apparatus have a problem in that the polishing water is sufficiently supplied to the workpiece to enhance the cooling effect and to improve the polishing ability. .

[0008]

As a specific means for solving the above-mentioned problems, the present invention provides a chuck table for holding a semiconductor wafer, a polishing means provided opposite to the chuck table, A polishing method for polishing a semiconductor wafer by a polishing apparatus including at least a polishing grindstone constituting means and a polishing water supply means for supplying polishing water to the semiconductor wafer, wherein the polishing apparatus rotates the surface of the semiconductor wafer held on a chuck table. When polishing a semiconductor wafer while supplying polishing water by contacting a polishing grindstone to be performed, the polishing is performed by injecting a gas so that the polishing water enters a contact portion between the semiconductor wafer and the polishing grindstone. A polishing method is provided.

When the polishing is performed, the chuck table is rotated, the polishing water is supplied from the inside of the polishing wheel and the gas is injected, the gas is air, and the semiconductor wafer is polished to 200 μm or less. Is an additional requirement.

The present invention is also directed to a chuck table for holding a workpiece, a polishing means including a polishing grindstone and disposed opposite the chuck table, and a polishing apparatus for supplying polishing water to the polishing grindstone and the workpiece. An object of the present invention is to provide a polishing apparatus including at least water supply means and gas injection means for injecting polishing water into a contact portion between a workpiece and a polishing grindstone.

According to such a polishing method and a polishing apparatus, the polishing water can sufficiently penetrate into the contact portion between the workpiece and the polishing grindstone, and the cooling effect of the workpiece during polishing is enhanced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A polishing apparatus for carrying out a polishing method according to the present invention is a polishing apparatus 30 shown in FIG.
It is different from the conventional polishing apparatus 30 in the point that the gas injection means 10 shown in FIGS. 1 to 3 is provided. Therefore, in the following description, the same parts as those of the conventional polishing apparatus 30 are denoted by the same reference numerals, and the description thereof will be omitted.

The main part of the polishing apparatus shown in FIG. 1 is constructed in the same manner as in the prior art. More specifically, the vertical movement of the polishing means 34, the rotation of the spindle 42, and the rotation of the chuck table 33 are all controlled by the controller 20. It is controlled and configured as follows.

A pulse motor 21 is provided on an upper portion outside the wall 38, and a driving portion 23 is engaged with a screw 22 driven and rotated by the pulse motor 21. The driving section 23 penetrates the wall 38 and is connected to the slide plate 40. Then, the control unit 20 drives the pulse motor 21 via the pulse motor driver 24, and the screw 22 rotates with the rotation of the pulse motor 21, so that the drive unit 23 moves up and down. The polishing means 34 moves up and down along 39.
Further, the driving unit 23 is directly connected to the control unit 20,
The rotation of the spindle 42 is driven under the control of the control unit 20.

A linear scale 25 is provided outside the wall 38. Position information of the drive unit 23 on the linear scale 25 is transferred to the control unit 20, and the position information is transmitted to the polishing means in the control unit 20. 34 is provided for precise control of the vertical movement of the actuator.

The control unit 20 includes a servo driver 2
6 and connected to an encoder 27 and a servomotor 28 provided below the chuck table 33,
The rotation of the chuck table 33 is controlled by driving the encoder 27 and the servomotor 28.

In the vicinity of the chuck table 33, there is provided a gas injection means 10 in which the nozzle 11 rises from the worktable 31, and the injection port 12 at the tip thereof is directed toward the chuck table 33. This gas injection means 1
0, a gas such as high-pressure air is supplied from the gas supply unit 13 and the gas 14 is injected from the injection port 12 as shown in FIG. In addition, the gas injection means 10 is the same as that shown in FIG.
As shown in FIG. 3A, the gas 14 may be injected from one fan-shaped injection port 12 provided in the nozzle 11 that can rotate and move up and down, or FIG.
As shown in (B), a plurality of injection ports 12 are arranged in the nozzle 11 in a divergent manner in the horizontal direction.
4 may be configured to be injected.

The polishing wheel 44 is, as shown in FIG.
A polishing water supply port 47 that is disposed in a circular shape at regular intervals and supplies polishing water to the wafer, and a polishing grindstone 48 that is circularly disposed at regular intervals on the outside thereof, The upper part is fixed to the mounter 43.

When a wafer is polished using the polishing apparatus constructed as described above, a wafer W to be polished is placed and held on a chuck table 33 as shown in FIG. Table 3 under the control of
3 while rotating the spindle 42 and rotating the polishing wheel 44 to lower the polishing means 34, and bringing the rotating polishing grindstone 48 into contact with the wafer W while applying an appropriate pressing force. Polish the surface.

At this time, the polishing water is preferably supplied to the polishing water supply passage 45 from 0.5 liter / min to 4.0 liter / min. Is supplied to the wafer W. At the same time, a gas is supplied to the gas injection means 10 to inject the gas 14 preferably at 3 to 4 atm from the injection port 12.

The flow of the polishing water 15 increases due to the injected gas 14, and forcibly enters a small gap in the contact portion between the wafer W and the polishing grindstone 48 as shown in FIG. Cooling of the wafer W is further promoted by the polishing water thus entered.

When the polishing is performed while supplying the polishing water and injecting the high-pressure air in this manner, and the cooling of the wafer W is promoted, the surface burn of the wafer W is hardly generated, and the polishing distortion and the crack are hardly generated. . Therefore, it is possible to perform mirror polishing by eliminating the surface roughness, and it is also possible to polish the wafer as thin as 200 μm or less, for example.

[0023]

As described above, according to the polishing method and the polishing apparatus according to the present invention, the polishing water can sufficiently penetrate into the contact portion between the workpiece and the polishing wheel, and the polishing during polishing can be performed. Since the cooling effect of the workpiece is enhanced, surface burn of the workpiece is less likely to occur, and polishing distortion and cracks are less likely to occur.
Therefore, the surface can be polished with no roughness and mirror polishing can be performed, and the wafer can be polished to have a thickness of, for example, 200 μm or less. Cards and the like can be formed thin.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a main part of a polishing apparatus according to the present invention.

FIG. 2 is an explanatory view showing a polishing means, a chuck table, and a gas injection means of the polishing apparatus.

FIG. 3 is a perspective view showing an example of gas injection means of the polishing apparatus.

FIG. 4 is an explanatory view showing a polishing wheel constituting a polishing means of the polishing apparatus.

FIG. 5 supplies polishing water using the polishing apparatus,
It is explanatory drawing which shows a mode that a wafer is grind | polished by injecting a gas.

FIG. 6 is an enlarged view of a portion indicated by A in FIG. 5;

FIG. 7 is a polishing apparatus showing a conventional polishing apparatus.

FIG. 8 is an explanatory view showing a polishing means and a chuck table of the polishing apparatus.

[Description of Signs] 10: Gas injection means 11: Nozzle 12: Injection port 1
3: Gas supply unit 14: Gas 15: Polishing water 20: Control unit 21: Pulse motor 22: Screw 2
3: Drive unit 24: Pulse motor driver 25: Linear scale 26: Servo driver 27: Encoder 28: Servo motor 30: Polishing device 31: Work table 32: Turntable 33: Chuck table 34: Polishing means 35: Transport means 36: Cleaning area 37: Cassette 38: Wall 39: Rail 40: Slide plate 41: Spindle housing 42: Spindle 4
3: Mounter 44: Polishing wheel 45: Polishing water supply path 46: Branch path 47: Polishing water supply port 48: Polishing whetstone 49: Polishing water

Claims (6)

[Claims] 1. A chuck table for holding a semiconductor wafer, polishing means disposed opposite to the chuck table, a polishing water supply for supplying polishing water to a polishing wheel and a semiconductor wafer constituting the polishing means. A polishing method for polishing a semiconductor wafer by a polishing apparatus including at least means, wherein the semiconductor wafer is supplied while a polishing water is supplied by contacting the rotating polishing grindstone with a surface of the semiconductor wafer held by the chuck table. A polishing method for performing polishing by injecting a gas so that the polishing water enters a contact portion between the semiconductor wafer and the polishing wheel during polishing. 2. The polishing method according to claim 1, wherein the chuck table rotates when performing the polishing. 3. The polishing method according to claim 1, wherein the polishing water is supplied from inside the polishing whetstone and the gas is injected. 4. The polishing method according to claim 1, wherein the gas is air. 5. The polishing method according to claim 1, wherein the semiconductor wafer is polished to 200 μm or less. 6. A chuck table for holding a workpiece,
A polishing means including a polishing whetstone, disposed in opposition to the chuck table, a polishing water supply means for supplying polishing water to the polishing whetstone and the work, and a polishing water supply means A polishing apparatus including at least gas injection means for injecting the polishing water into the contact portion.