JP2916028B2 - Mirror polishing method and apparatus for work edge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art For example, various processes have been performed on the outer peripheral edge portion of a semiconductor wafer such as a silicon wafer in order to minimize the influence of contamination in subsequent processes.
That is, chamfering with a diamond grindstone for preventing chipping, etching for removing the work distortion layer after chamfering, and the like.

[0003] However, the surface of the etched edge is wave-like or scale-like, and dirt tends to remain, causing deterioration of the wafer characteristics.

[0004] In order to solve such a problem, the present inventors have proposed, as disclosed in Japanese Patent Application Laid-Open No. Sho 64-71656, an edge of a rotating work held on a turntable. pressing a polishing ring to rotate, the edge the polishing ring proposed a processing apparatus adapted to mirror finishing, addition, to handle the large amount of work continuously, Japanese Patent Application No. 1-258505 (JP-3- 208
No. 550), a plurality of index units for holding a work are mounted at fixed intervals on an index table which can be intermittently rotated by a certain angle, and the edges of the work supplied to these index units one after another are formed. A processing device has been proposed in which the polishing is performed by pressing against a polishing drum located at the center of the index table.

However, as shown in FIG. 6, all of these processing apparatuses employ a method in which an edge of a work 20 is pressed against a polishing ring or a polishing cloth 22 on the outer periphery of a polishing drum 21 to perform polishing. The contact length m of the work with the polishing drum 21 is short, and
There is a problem that it takes a considerable time until the entire circumference of the work 20 is polished. In recent years, the diameter of wafers has been increasing, and as the manufacturing process for 8-inch diameter wafers has become more and more lined up, demands for improving the yield have increased, and there is an urgent need to shorten the processing time.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus for mirror-polishing, which can mirror-polish a large-diameter wafer in a short time.

[0007]

In order to solve the above-mentioned problems, a first mirror polishing method according to the present invention employs a method in which a pressure is applied to an inner peripheral surface.
Inside a cylindrical polishing drum having a compression resistance of certain polishing cloth, the outer peripheral edge smaller in diameter than the inner diameter of the polishing drum to insert a surface <br/> up processed disc-shaped workpiece, the While rotating the work and the polishing drum around the central axis, a part of the chamfered edge of the outer periphery of the work is polished.
The work edge is mirror-polished by pressing against a polishing cloth on one side of the inner peripheral surface of the ram . In addition, the second mirror polishing method of the present invention uses a polishing cloth having compressibility on both the inner peripheral surface and the outer peripheral surface.
Using a cylindrical polishing drum equipped with a polishing cloth on the outer peripheral surface, the edge of the orientation flat part on the outer periphery of the disk-shaped work whose edge has been chamfered is polished, and the outer peripheral polishing cloth is polished with a polishing cloth on the inner peripheral surface. A mirror polishing method for a work edge, comprising polishing an edge of a round portion of a workpiece.

On the other hand, the first mirror-polishing apparatus of the present invention, the inner painting Bei polishing cloth with a compressible peripheral surface, and a cylindrical polishing drum drivable rotation about a central axis, said polishing Dora
And chuck periphery of the edge a smaller diameter than the inner diameter of the beam is a chamfered disc-shaped workpiece, with rotating the workpiece about a central axis within the polishing drum, 該Wa
Part of the chamfered edge around the outer periphery of the polishing drum
A chuck table for pressing the polishing cloth on one side of the peripheral surface . A second mirror polishing apparatus according to the present invention further comprises a cylindrical polishing drum having compressible polishing cloths on both an inner peripheral surface and an outer peripheral surface, the cylindrical polishing drum being rotatable around a central axis, and chamfering an edge. Means for pressing an edge of an orientation flat portion on the outer periphery of the processed disk-shaped work against a polishing cloth on an outer peripheral surface of the polishing drum to move the work in parallel with the orientation flat portion; and an edge of a round portion on the outer periphery of the work. Means for pressing the workpiece against a polishing cloth on the inner peripheral surface of the polishing drum to rotate the work about a central axis.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. In FIG. 1, reference numeral 1 denotes a chuck table for holding a disk-shaped work 2, and 3 denotes a cylindrical polishing drum for mirror-polishing an outer edge 2a (see FIG. 2) of the work 2.

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

On the other hand, the polishing drum 3 is rotatably supported by a support arm 8 and is driven and rotated around a central axis by a motor 9.
Is mounted on a support 10 erected on a base 6 so as to be able to move up and down. A polishing cloth 12 is adhered to the inner peripheral surface of the cylindrical polishing drum 3, and the edge 2 a of the work 2 is polished on the inner peripheral surface.

In the mirror polishing apparatus having the above configuration,
When a work 2 having chamfered edges 2a on both outer surfaces is supplied to the head 5 of the chuck table 1 at the position indicated by the solid line in FIG.
Moves right below the polishing drum 3 as shown by a chain line in FIG. Subsequently, when the polishing drum 3 is lowered and the work 2 is inserted therein, the polishing drum 3 and the head 5 start rotating, and as shown in FIGS. 5, the edge 2a of one surface of the work 2 is pressed against the inner peripheral surface of the polishing drum 3, and the edge 2a is mirror-polished.

After a certain period of time, the polishing drum 3 and the chuck table 1 return to the state shown by the solid line in FIG. 1 and the work 2 is turned upside down. Then, the edge 2a on the opposite side of the workpiece 2 is mirror-finished in the same manner as described above. The polishing drum 3 and the head 5 may be rotated in the same direction or in opposite directions, but if they are rotated in the same direction, a difference in rotation speed is required.
Is required.

Here, as in the present invention, the work edge 2a
The difference between the effect of polishing on the inner peripheral surface of the polishing drum 3 and the effect of polishing on the outer peripheral surface of the polishing drum 3 as in the prior art is based on FIGS. 4 (present invention) and 6 (conventional example). To compare. Now, in order to make the both polishing conditions the same, the diameter of the polishing drum (inner diameter in FIG. 4 and outer diameter in FIG. 6) is 300 mm, 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, a case where the work is pressed at right angles to the inner peripheral surface of the polishing drum for easy understanding will be described. In the present invention, the contact length n at which the work 2 comes into contact with 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. Normally, the processing time of the work is inversely proportional to the length of contact with the polishing cloth. Therefore, according to the method of the present invention, the work edge can be mirror-polished in a processing time that is 1/2 or less of the conventional processing time. Even when the work is inclined 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. .

In the present invention, it goes without saying that the diameter (inner diameter) of the polishing drum 3 is changed to one suitable for the outer diameter of the work 2, the chamfer 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 must be
It is desirable to make the outer diameter as close as possible.

In the above 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. First, after polishing the edge 2a on one side of the work 2 on one side, the work 2 is turned upside down and the edge 2a on the opposite side is polished on the other side. Can also.

The polishing of the edge 2a of the orientation flat portion 2c formed on the workpiece 2 may be performed in a step different from the polishing of the edge 2a of the round portion 2b, but the round portion 2b is polished. In this case, the polishing can be performed using the polishing drum 3. in this case,
As shown in FIG. 5, the polishing cloth 12 a is also attached to the outer peripheral surface of the polishing drum 3, and the orientation flat portion 2 c is attached to the outer peripheral surface of the polishing drum 3 by the chuck table 1 before polishing the round portion 2 b of the work 2. The polishing is performed by rotating the polishing drum 3 while pressing and reciprocating the work 2 in parallel with the orientation flat. Thereafter, the work 2 is inserted into the polishing drum 3 as described above, and the round portion 2b is polished. The same applies when the work 2 is reversed.

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

[0019]

As described above, according to the present invention, a compressible polishing cloth is adhered to the inner peripheral surface of the cylindrical polishing drum, and the chamfered edge of the outer periphery of the disk-shaped work is formed inside the polishing drum. The inner peripheral surface of the polishing drum is curved because one side of the peripheral surface is pressed against the polishing cloth and polished.
And the abrasive cloth has compressibility.
Non contact length of the workpiece edge against the polishing cloth I
Can always be made longer, as a result, it is possible to mirror-polish the workpiece edge in a short time even wafers having a large diameter. In addition, by using a polishing drum having a polishing cloth attached to both the inner and outer peripheral surfaces, even if the workpiece has an orientation flat portion on the outer periphery, the edge of the round portion is the inner peripheral polishing cloth. Since the edge of the orientation flat portion can be polished with a polishing cloth on the outer periphery, the edge can be surely polished over the entire periphery of the work in a short time.

[Brief description of the drawings]

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

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

FIG. 3 is an enlarged longitudinal sectional view of a main part in a polished state of FIG. 1;

FIG. 4 is an enlarged cross-sectional view of a main part in a polished state of FIG. 1;

FIG. 5 is an enlarged cross-sectional view of a main part showing a different polishing mode of FIG. 1;

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

[Explanation of symbols]

 Reference Signs List 1 chuck table 2 work 2a edge 2b round part 2c orientation flat part 3 polishing drum 12 polishing cloth

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-107979 (JP, A) JP-A-2-250776 (JP, A) JP-A-2-250766 (JP, A) 79970 (JP, A) JP-A-62-157779 (JP, A) JP-A-63-60556 (JP, U) JP-A-63-113563 (JP, U) JP-A-63-64460 (JP, U)

Claims (4)

(57) [Claims] Inside of claim 1] in <br/> cylindrical polishing drum having a polishing cloth with a compressible peripheral surface, than the inner diameter of the polishing drum
The outer periphery of the edge diameter is inserted a work disk-shaped which is chamfered, while rotating the workpiece and the grinding drum and the around each central axis is chamfered of the workpiece outer circumference
A method for mirror-polishing a work edge, comprising: pressing a part of the formed edge against a polishing cloth on one side of an inner peripheral surface of a polishing drum to mirror-polish the work edge. 2. Compression polishing for both inner and outer peripheral surfaces.
Using a cylindrical polishing drum equipped with a cloth, the edge of the orientation flat portion on the outer periphery of the disc-shaped work whose edge is chamfered with the polishing cloth on the outer peripheral surface is polished, and the inner peripheral surface is polished. Polishing the edge of the round portion on the outer periphery of the work with the polishing cloth of (1). 3. An inner peripheral surface having a compressible polishing cloth.
In addition , a cylindrical polishing drum that can be driven and rotated around a central axis, and a disk-shaped work whose diameter is smaller than the inner diameter of the polishing drum and whose outer peripheral edge is chamfered, are chucked, and the work is placed in the polishing drum. At the same time, the workpiece is rotated around the center axis and a part of the chamfered edge on the outer periphery of the work is ground.
A chuck table for pressing the polishing cloth on one side of the inner peripheral surface of the polishing drum; and a mirror polishing apparatus for a work edge. 4. Polishing with compressibility on both inner and outer peripheral surfaces
A cylindrical polishing drum having a cloth, which can be driven and rotated around a central axis , and an edge of an orientation flat portion on the outer periphery of a disc-shaped work having chamfered edges pressed against the polishing cloth on the outer peripheral surface of the polishing drum. Means for moving the work in parallel with the orientation flat portion, and means for pressing the edge of the round portion on the outer periphery of the work against a polishing cloth on the inner peripheral surface of the polishing drum to rotate the work around a central axis. A mirror polishing device for a work edge, comprising: