JPH0523959A - Mirror grinding method and device of work edge - Google Patents

Abstract

PURPOSE:To provide a mirror grinding method and the device which is able to grind a work edge into mirror finishing in a short time even if it is of a large diametral wafer. CONSTITUTION:A work 2, whose peripheral edge part is chamfered, is held by a chuck table, while this work 2 is inserted into the inner part of an abrasive drum 3, pressing its edge 2a to abrasive cloth 12 on an inner circumferential surface of the abrasive drum 3, and the work 2 and the abrasive drum 3 are rotated, thus the edge 2a is ground into mirror finishing. Therefore, contact length of the work in contact with the abrasive cloth is longer as compared with the conventional method that grinds the work by pressing it to an outer circumferential surface of the abrasive drum, so that a span of machining time can be shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for mirror-polishing a work edge, and more particularly to the edge of a disk-shaped work such as a semiconductor wafer, a glass plate, a quartz plate or a ceramic substrate. The present invention relates to a mirror polishing method and device for mirror polishing a portion.

[0002]

2. Description of the Related Art For example, a peripheral edge portion of a semiconductor wafer such as a silicon wafer has been subjected to various treatments in order to minimize the influence of contamination in the subsequent process.
That is, a chamfering process using a diamond grindstone for preventing chipping, an etching process for removing the processed strained layer after the chamfering process, and the like.

However, the surface of the edge subjected to the etching process becomes wavy or scale-like and stains are liable to remain, which causes deterioration of the characteristics of the wafer.

Therefore, in order to solve such a problem, the inventors of the present invention, as disclosed in Japanese Patent Laid-Open No. 64-71656, use an edge of a work held on a turntable and rotating. Japanese Patent Laid-Open No. 1-258505 discloses a processing device in which a rotating polishing ring is pressed, and an edge is mirror-finished by the polishing ring. In this way, a plurality of index units that hold the work are attached at regular intervals on an index table that can be intermittently rotated by a fixed angle, and the edges of the work that are successively supplied to these index units are
We proposed a processing device that presses against a polishing drum located in the center of the index table to perform polishing.

However, since all of these processing devices are of a type in which the edge of the work 20 is pressed against the polishing ring or the polishing cloth 22 on the outer periphery of the polishing drum 21 as shown in FIG. 6, the polishing ring or The contact length m of the work with the polishing drum 21 is short, and therefore,
There is a problem that it takes a considerable time to finish polishing the entire circumference of the work 20. Moreover, in recent years, the diameter of wafers has tended to increase, and as the manufacturing process of 8-inch diameter wafers has been lined up, the demand for improved yields has increased, and there is an urgent need to reduce processing time.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a mirror polishing method and apparatus capable of mirror polishing a large diameter wafer in a short time.

[0007]

In order to solve the above problems, a mirror polishing method of the present invention is to insert a disk-shaped work into a cylindrical polishing drum having a polishing cloth attached to the inner peripheral surface thereof, The work edge is mirror-polished by pressing the work edge against the polishing cloth while rotating the work and the polishing drum.

Further, the mirror-polishing apparatus of the present invention chucks a drive-rotatable cylindrical polishing drum having a polishing cloth attached to its inner peripheral surface and a disk-shaped work, and holds the work in the polishing drum. A chuck table for pressing an edge against the polishing cloth is provided.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, 1 is a disk-shaped work 2
The chuck table 3 for holding the workpiece 2 is a cylindrical polishing drum for mirror-polishing the edge 2a (see FIG. 2) on the outer periphery of the work 2.

The chuck table 1 is provided with a head 5 having a chuck means such as a vacuum chuck, which holds the work 2 by the head 5, and moves in the XY directions on the base 6 by a moving means (not shown). The head 5 is also configured to be rotatable about the axis by the driving means and tiltable by a predetermined angle θ.

On the other hand, the polishing drum 3 is rotatably supported by a supporting arm 8 and is driven by a motor 9. The supporting arm 8 is lifted up and down by a column 10 standing on a base 6. It is attached freely. A polishing cloth 12 is attached to the inner peripheral surface of the cylindrical polishing drum 3, and the edge 2a of the work 2 is polished by the inner peripheral surface.

In the mirror polishing apparatus having the above structure,
When a work 2 having chamfered edges 2a on both sides is supplied to the head 5 of the chuck table 1 at the solid line position in FIG.
Moves right below the polishing drum 3 as shown by the chain line in the figure. Subsequently, when the polishing drum 3 descends and the work 2 is inserted therein, the polishing drum 3 and the head 5 start rotating, and as shown in FIGS. 3 and 4, the head of the chuck table 1 is moved. 5 is inclined and the edge 2a on one surface of the work 2 is pressed against the inner peripheral surface of the polishing drum 3, and mirror polishing of the edge 2a is performed.

After a certain period of time, the polishing drum 3 and the chuck table 1 once return to the state shown by the solid line in FIG. 1, and the work 2 is turned upside down. Then, similarly to the case described above, the edge 2a on the opposite side of the work 2 is mirror-finished. The polishing drum 3 and the head 5 may be rotated in the same direction or in opposite directions, but in the case of rotating in the same direction, it is necessary to give a rotation speed difference.

Here, the work edge 2a as in the present invention.
Based on FIG. 4 (present invention) and FIG. 6 (conventional example), the difference in effect between the case where the inner peripheral surface of the polishing drum 3 is polished and the case where the outer peripheral surface of the polishing drum 3 is conventionally polished is described. Consider it. In order to make the polishing conditions the same, the diameter of the polishing drum (inner diameter in FIG. 4, outer diameter in FIG. 6) is 300 mm, and the thickness of the polishing cloth is 1.25 mm.
Assuming that the outer diameter of the work is 200 mm and the polishing cloth is compressed to 0.25 mm by pressing the work, the case where the work is pressed at a right angle to the inner peripheral surface of the polishing drum for easy understanding will be described. In the present invention, the contact length n with which the workpiece 2 contacts the polishing cloth 12 is about 34.7 mm, and the contact length m in the conventional example is about 15.5 mm. More than twice as long. Since the working time of the work is normally inversely proportional to the contact length with the polishing cloth, the work edge can be mirror-polished in less than half the working time of the conventional method. Even when the work is tilted and pressed against the inner peripheral surface of the polishing drum, the relationship between the contact lengths m and n is substantially the same as in the case described above, and therefore the effect is not different from that described above. .

In the present invention, the diameter (inner diameter) of the polishing drum 3 can be changed to a suitable one according to the outer diameter of the work 2, the chamfering angle of the edge 2a, the inclination angle of the head 5 and the like. However, in order to make the contact length m as large as possible, the inner diameter of the polishing drum 3 should be set to
It is desirable to make it as close as possible to the outer diameter of.

In the above-mentioned embodiment, the work 2 is turned upside down by one set of the chuck table 1 and the polishing drum 3 to polish the edges 2a on both sides. A chuck table and a polishing drum are provided, and first, the edge 2a on one side of the work 2 is polished on one side, then the work 2 is turned upside down and the edge 2a on the opposite side is polished on the other side. You can also

The edge 2a of the orientation flat portion 2c formed on the work 2 may be polished in a step different from the step of polishing the edge 2a of the round portion 2b, but the round portion 2b is polished. At that time, the polishing drum 3 can be used. in this case,
As shown in FIG. 5, a polishing cloth 12a is also attached to the outer peripheral surface of the polishing drum 3, and the orientation flat portion 2c is attached to the outer peripheral surface of the polishing drum 3 on the chuck table 1 before polishing the round portion 2b of the work 2. While pressing, the work 2 is reciprocated in parallel with the orientation flat, and the polishing drum 3 is rotated for polishing. Then, as described above, the work 2 is inserted into the polishing drum 3 to polish the round portion 2b. The same applies when the work 2 is reversed.

In the present invention, a plurality of works may be inserted into one polishing drum and the edges of these works may be simultaneously polished by the polishing drum.

[0019]

As described above, according to the present invention, the polishing cloth is attached to the inner peripheral surface of the cylindrical polishing drum, and the work is pressed against the inner peripheral surface of the polishing drum to perform polishing. The contact length of the work with the cloth can be increased, and as a result, even a large diameter wafer can be mirror-polished in a short time.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view schematically showing an embodiment of a polishing apparatus of the present invention.

FIG. 2 is a partially enlarged sectional view of a work.

3 is an enlarged vertical sectional view of an essential part in the polishing state of FIG.

FIG. 4 is an enlarged cross-sectional view of a main part in the polishing state of FIG.

FIG. 5 is an enlarged cross-sectional view of an essential part showing a different polishing mode of FIG.

FIG. 6 is a cross-sectional view of a main part showing a conventional polishing method.

[Explanation of symbols]

1 chuck table 2 work 2a Edge 3 Polishing drum 12 polishing cloth

Claims (2)

[Claims] 1. A polishing cloth is attached to the inner peripheral surface of a cylindrical polishing drum, a disk-shaped workpiece is inserted into the polishing drum, and the workpiece edge is polished while rotating the workpiece and the polishing drum. A mirror polishing method for a work edge, which comprises polishing the work edge by mirror pressing. 2. A cylindrical polishing drum which has a polishing cloth attached to an inner peripheral surface thereof and is rotatable freely, and a chuck table which chucks a disk-shaped work and presses the work edge against the polishing cloth in the polishing drum. A mirror polishing device for a work edge, comprising: