JPH10113866A - Dresser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out dressing of an abrasive cloth at optional time during specular processing or by stopping the specular processing by providing diamond particles to dress a polishing means in a groove formed on an outer periphery of a rotative ring mount. SOLUTION: A polishing disc which is a disc type specular processing means to specular-process a notch part surface while rotating it is concentrically fixed on the other end of a spindle. A diamond rotational dresser 40 as a diamond tool to mold or dress an abrasive cloth of the polishing disc is the one burying diamond 40a in a groove formed on an outer periphery of a ring mount 41, the one formed by holding diamond particles in a groove by a sintered metal bond or the one forming the diamond 40a on a groove surface by an electrodeposition method for use.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dresser for dressing notch polishing means for mirror-finishing a notch formed in a peripheral portion of a semiconductor wafer or the like.

[0002]

BACKGROUND OF THE INVENTION Conventionally, an orientation flat, a substantially V-shaped or a substantially arc-shaped notch is formed in a peripheral portion of a wafer. Accordingly, it is widely used for the purpose of improving the yield.

As shown in FIG. 5A, a wafer 10 having a V-shaped notch 10a formed thereon is chamfered at both upper and lower corners of the edge in order to prevent chipping of the edge and crown during epitaxial growth. Parts 10b and 10c
Are formed. In order to remove the remaining of the processing distortion layer at the edge at the time of chamfering, there has been proposed a mirror finishing apparatus for performing mirror finishing by bringing a drum-shaped mirror finishing means into contact with the chamfered portions 10b and 10c (for example, And JP-A-1-274958.

On the other hand, the size of the notch 10a of the wafer 10 on which the notch 10a is formed is extremely small as compared with the outer peripheral length of the wafer 10. Therefore, the notch 10a is formed by using the drum-shaped mirror surface processing means. However, it was difficult to perform mirror finishing. Therefore, there has been a strong demand for the development of a notch mirror processing apparatus and a dresser for dressing a polishing means capable of efficiently mirror-polishing the notch portion and improving the yield.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dresser for a polishing means for performing a mirror finishing operation for a notch portion.

[0006]

The dresser of the present invention comprises:
Diamond grains for dressing the polishing means are provided in grooves formed on the outer periphery of the rotatable ring-shaped mount, and the polishing means is dressed by rotating the dresser.

[0007]

FIG. 1 shows a front view of a mirror finishing apparatus for a notch portion according to the present invention. In FIG. 1, 1 is a motor, 2 is a pulley connected to the motor 1, 3 is a transmission belt, 4 is a pulley connected to the transmission belt 3, and the pulley 4 is a spindle 6 held through a headstock 5. It is connected to. The other end of the spindle 6 is concentrically fixed with a polishing disk 8 which is a disk-shaped mirror-finish means for mirror-finish while rotating a notch surface described later. 9a and 9b are metal motor fixing plates provided on the headstock 5, and the motor 1 is fixed on the motor fixing plate 9a. Between the motor fixing plates 9a and 9b and between the headstock 5 and the fixing plate 9b.
In order to prevent the rotational vibration of the motor 1 from being transmitted to the headstock 5, the vibration absorbers 9 c and 9 d are interposed, for example, with vibration-proof rubber.

Reference numeral 10 denotes a semiconductor wafer having a notch 10a formed thereon (FIG. 5). The wafer 10 intersects the polishing disk 8 on a wafer chuck table 12 which is rotatably provided on a bracket 11 as described later. , In particular, orthogonally. On the upper surface of the wafer chuck table 12, vacuum chuck means 12b for chucking the wafer 10 is formed.

Reference numeral 13 denotes a headstock mounting stand, which is mounted on a base 15 via a slide means 14. Further, the bracket 11 is fixed to the base 15.

A slide table 14a that slides in a direction perpendicular to the paper surface is fixed to the lower surface of the headstock mounting frame 13, and the slide table 14a is mounted on a slide bed 14b that forms a slide rail. Further, the slide means 14 is provided with a linear motion bearing 14c so that frictional resistance is reduced and linear motion is smoothly performed.

Reference numeral 16 denotes a pulley rotatably mounted on a bracket 17 fixed to the base 15. A wire 18 is hung on the pulley 16, and a weight 19 is attached to one end of the wire 18. The other end of the wire 18 is hung by a projection (not shown) provided on the upper surface of the headstock mounting base 13. The headstock 5 is moved forward by the slide means 14 due to the tensile load by the weight 19 and the wire 18, and as a result, the polishing disk 8 fixed to the spindle 6 is pressed by a predetermined pressure onto the notch of the wafer 10. The contact is made by pressure. Reference numeral 20 denotes a slurry scattering prevention cover for preventing the polishing disk 8 from rotating and scattering the slurry during mirror polishing.

Next, the polishing disk 8 will be described. As shown in FIGS. 1 and 2, the polishing disk 8 includes a polishing cloth holding ring 7a, and the polishing cloth 7 is attached so as to surround the periphery of the polishing cloth holding ring 7a. Further, the disk-shaped holding members 8a and 8b are fixed to the polishing cloth holding ring 7a with screws 8c or the like so as to sandwich the polishing cloth 7 and the polishing cloth holding ring 7a from both sides.

Alternatively, the polishing disk 8 is mounted on the outer periphery of a ring 7a for holding a thick ring-shaped polishing cloth 7, and then clamped by screws 8c by disk-shaped clamping members 8a and 8b. Is also good. When this thick polishing cloth is used, the polishing cloth 7 may be composed of a plurality of stacked polishing cloths.

The disk-shaped holding members 8a and 8b and the polishing cloth holding ring 7a are fixed to a spindle mounting flange 21 with bolts 22 with holes, and an end of the spindle 6 has a center axis coincident with the spindle mounting flange 21. It is linked to be.

The polishing cloth holding ring 7a and the disc-shaped holding members 8a and 8b are formed of stainless steel.
A polishing cloth usually used for mirror finishing of the surface of a semiconductor wafer is used. For example, it is preferable to use a polishing cloth made of a high-quality nonwoven fabric resin-treated resin or a polishing cloth made of polyurethane resin. Further, as another configuration of the polishing disk, a polishing cloth 7 may be attached to a peripheral portion of the holding ring 7a with a double-sided adhesive tape.

Incidentally, the peripheral portion of the semiconductor wafer 10
As shown in FIG. 5A, both corners are chamfered 10b and 10c at a predetermined angle θ. Normal notch 10a
5B, FIG. 5C and FIG. 5D.
As shown in FIG. 5, a notch chamfered portion is formed by chamfering at a predetermined angle θ, for example, at an angle of 11 degrees, 22 degrees, or the like. Therefore, in the mirror processing apparatus for the wafer notch portion of the present invention, the wafer chuck table 12 is rotated up and down by a predetermined angle to tilt the semiconductor wafer 10 by a predetermined angle, so that the chamfered portion and the mirror surface can also be processed.

Hereinafter, a tilting mechanism of the wafer chuck table 12 for tilting the wafer 10 will be described with reference to FIGS. 3 and 4, a bracket 1 supporting the wafer chuck table 12 is shown.
At both ends of the wafer chuck table on the 1 and 11 sides,
Heads 23a, 23a of pins 23, 23 serving as pivot points of rotation
Is fixed to the wafer chuck table 12.

On the other hand, a rotating plate 24 to which a vacuum tube 25 is connected is fixed to the lower surface of the wafer chuck table 12, and L-shaped connecting members 26 are provided on both sides of the rotating plate 24. 26 is fixed by bolts or the like.

Further, the bracket 11 has an arc-shaped slit 2 centered on the center 23b of the pins 23,23.
7 is formed, and fastening means 28, for example, a hexagonal bolt, is inserted through the arc-shaped slit 27 to the L-shaped member 2.
6 is provided to be screwed. In order to rotate the rotating plate 24 with the pin 23 as a fulcrum, the hexagonal bolt 28 is manually loosened and the hexagonal bolt 28 is slid along the arcuate slit 27.

In order to hold the rotating plate 24 in a horizontal position, the tightening position of the hexagon bolt 28 is set so as to be located at the center of the slit 27. In this way, when the hex bolt 28 is slid upward or downward from the center of the slit 27,
In conjunction with this, the vacuum chuck table 12 tilts up and down with the pin 23 as a fulcrum. As a result, the semiconductor wafer 10 also tilts up and down by a predetermined angle.

At this time, even if the semiconductor wafer 10 is tilted by a predetermined angle, the center of rotation of the pin 23 is so set that the mirror-finished portion of the notch 10a (FIG. 5) always contacts the center of rotation 8c of the polishing disk 8. The position of 23b is set.
In this manner, as shown in FIG. 4, the rotation center 8 of the polishing disk 8 is moved by the sliding means 14 (FIG. 1).
Since c is configured to move toward the rotation center 23b of the pin 23, even when the polishing cloth 7 sinks due to the elastic action of the polishing cloth 7, the polishing disk 8 moves accordingly. Therefore, the mirror-finished portion of the notch is always pressed from the normal direction to the polishing cloth 7, and a uniform mirror-finished surface is obtained. Further, when performing the mirror finishing of the chamfered portion and the non-chamfered portion, even if there is a change in the mirrored portion, it is not necessary to perform the vertical position correction of the notch portion 10a or the polishing disk 8 each time it is changed. Mirror processing can be easily performed.

By adjusting the inclination of the semiconductor wafer 10 in this manner, the notch chamfered portion can be easily mirror-finished.

Here, an example of the inclination angle of the semiconductor wafer 10 when the notch chamfered portion and the mirror finish are performed will be described. When the notch chamfered portion of the semiconductor wafer whose both upper and lower corners are chamfered at an angle of 22 degrees is mirror-polished, the processing inclination angle of the semiconductor wafer 10 is set to about 45 degrees in consideration of the elastic action of the polishing pad 7. The hexagonal bolt 28 is slid up and down to be fixed, and when the non-notched chamfered portion is mirror-finished, the hexagonal bolt 28 is fixed at the center position of the slit 27.

The processing inclination angle of the semiconductor wafer 10 may be adjusted between horizontal and 79 degrees according to the hardness of the polishing pad 7 without depending on the processing inclination angle. The slit 27 shown in FIG. 4 can be adjusted only up to a processing inclination angle of a maximum of 45 degrees. However, when the processing inclination angle is increased, the area of the bracket 11 may be increased and the slit 27 may be extended.

In particular, when a hard polishing cloth is used, it is preferable to extend the slit 27 so that the working inclination angle is about 79 degrees. In order to continuously adjust the mirror finishing angle, an actuator for sliding the hexagon bolt 28 may be provided to gradually change the mirror finishing angle, or to stop at each mirror finishing portion. It may be mirror-finished.

Next, the rotation speed of the polishing disk 8 is:
As an example, the weight of the weight 19 (FIG. 1) is 450 g.
Is adopted as 528 rpm, but is changed according to the processing time and the load of the weight 19. The weight of the weight 19, that is, the magnitude of the pressing force differs depending on the processing conditions.
The setting is made in consideration of the balance with the holding force of 0 and the strength and hardness of the polishing pad.

The direction of rotation of the polishing disk 8 is as follows.
In the above, it is preferable to rotate in the counterclockwise direction as shown in FIG. 5D, and in the clockwise direction in FIG.

Hereinafter, a method of mirror processing the notch portion 10a of the wafer 10 using the notch portion mirror processing apparatus having the above configuration will be described. The wafer 10 having the chamfered notch portion 10a is placed on the wafer chuck table 12,
After being sucked and held horizontally by the vacuum chuck means 12b, the supply of the slurry is started. Next, rotation of the polishing disk 8 is started, and when a predetermined rotation speed is reached, the headstock mounting base 13 is slid to bring the polishing cloth 7 into contact with the notch portion 10a. In this state, the non-chamfered portion of the notch portion 10a is mirror-finished.

After the mirror finishing of the non-chamfered portion, the rotation of the polishing disk 8 is stopped, the hexagonal bolt 28 is operated, and the rotary table 24 is tilted upward or downward by a predetermined angle, and the polishing disk 8 is again rotated. Is rotated to perform mirror finishing of the notch chamfered portion or (FIG. 5). Thus, by performing mirror finishing on the entire surface of the notch portion, the entire surface of the notch portion is uniformly mirror-polished.

Next, another embodiment will be described with reference to FIGS. 6, 7 and 8. FIG. This embodiment is different from the first embodiment in that the polishing disk 8 and the driving means provided on the headstock mounting base 13 moved by the slide means 14 are changed to other structures. Hereinafter, an example in which a band-shaped mirror surface processing means is used as the mirror surface processing means will be described. In FIGS. 6, 7A and 8, reference numeral 30 denotes a polishing belt. The polishing belt 30 is hung on a driving pulley 31 and a driven pulley 32 so that an appropriate tension is applied. .

The transmission shaft 33 of the driving pulley 31 is connected to the spindle 6 in the first embodiment and rotates to move the polishing belt 30 upward or downward in cooperation with the driven pulley 32 and the transmission shaft 34. The driving pulley 31 and the driven pulley 32 allow the polishing belt 30 to run in a direction perpendicular to a direction in which the polishing device slides (FIG. 1).

The polishing belt 30 has a shape corresponding to the notch shape of the semiconductor wafer 10 as shown in an enlarged view in FIG. 7A, and is a Suba 40 manufactured by Rodale.
0 and polyurethane resin.
Further, the wafer 10 includes the driving pulley 31 and the driven pulley 3
2 so as to be in contact with the polishing belt 30 at substantially the center. The wafer holding means is held on the same wafer chuck table 12 as in the first embodiment, and the wafer tilting means of the first embodiment can be employed as it is to tilt the wafer 10 up and down.

In order to prevent the polishing belt 30 from escaping in the direction away from the wafer 10 when the wafer 10 comes into contact with the polishing belt 30, the belt holding member 35 is notched as shown in FIG. Move back and forth by urging means such as a spring so as to come in contact with and separate from the mirror-finished part of the part,
Further, it is provided so as to be able to rotate in conjunction with the polishing belt 30.

One example of the belt pressing member 35 is shown in FIG.
FIG. 8B is a sectional view taken along line AA ′ of FIG. The belt holding groove 3 into which the polishing belt 30 can be loosely fitted is provided substantially at the center of the outer circumference of the belt holding member 35 in the thickness direction.
6 are formed and rotate in conjunction with the polishing belt 30. The polishing belt 30 is formed by such a belt pressing member 35.
Is pressed against the notch of the wafer 10, the pressing force can be directed to the center of the wafer 10, and the same effect as in the first embodiment can be obtained.

Next, instead of the polishing belt 30 and the polishing belt pressing member 35, a belt-shaped polishing tape as shown in FIG. 7B can be used. In FIG. 7B, reference numeral 30a denotes a band-shaped polishing tape, and 35a denotes a circular polishing tape pressing member. The polishing tape pressing member 35a has a convex tape pressing portion 36 corresponding to the notch shape of the wafer at a substantially middle portion in the thickness direction of the outer periphery thereof.
a is formed on the outer periphery, and the belt-shaped polishing tape 30
Rotate in conjunction with a. By pressing the belt-shaped polishing tape 30a against the notch portion of the wafer 10 with such a polishing tape pressing member 35a, the polishing tape 3
Since 0a is in contact, the same effect as in the first embodiment can be obtained.

Next, the polishing disk and the polishing belt are
Before use, it is necessary to form into a shape corresponding to the notch shape, and after long use, it is necessary to perform dressing (reshaping).

Hereinafter, an embodiment of the present invention having a molding or dressing means will be described with reference to FIGS. FIG. 9 shows an example of a processing apparatus using a diamond rotating dresser 40 as a diamond tool for forming or dressing the polishing cloth 7 of the polishing disk 8. In FIG. 9, a diamond 40a is densely formed as a rotating dresser 40 on the outer periphery so as to have a predetermined shape.
Use a dresser provided with. As shown in FIG. 10A, the rotary dresser 40 is provided with a ring-shaped mount 4.
A diamond 40a is buried in the groove formed on the outer periphery of 1, a diamond grain is formed in the groove by holding a sintered metal bond, or a diamond 40a is formed on the groove surface by an electrodeposition method.

In the rotary dresser 40, the diamond 40a is provided in a groove formed on the outer periphery of the mount 41. As shown in FIGS. 10B and 10C, the shape of the groove 42 in which the diamond is held is formed. , A shape corresponding to the wafer shape (wafer V notch or U notch) is desirable, and as an example, the intersection angle β
Is preferably formed at 90 degrees or 110 degrees. The intersection angle β of the inclined portion is not limited to the angle,
The angle may be any angle between 70 degrees and 130 degrees depending on the hardness of the polishing pad 7. If the two types of rotary dressers are prepared, the polishing pad 7 can be dressed in a shape fitted to the wafer notch.

The rotating dresser 40 thus configured is fixed coaxially to the dresser rotating shaft 43, and has a U-shaped bearing 44.
To support. The dresser rotation shaft 43 includes a motor 4
6 is coupled via a coupling 48 to a motor rotating shaft 46a that penetrates one side plate 47a of an L-shaped connecting member 47 formed integrally with a motor mounting base 45 on which the motor 46 is mounted. Thereby, the rotary dresser 40 rotates.

The other side plate 47 of the L-shaped connecting member 47
The U-shaped bearing 44 is fixed to the front surface of the b.
Further, a guide projection (not shown) is formed on the back surface of the other side plate 47b, and the rotary dresser 4
A linear guide for raising and lowering 0 is constructed.

Further, in FIG. 9, reference numeral 50 denotes a housing fixed at a predetermined position up to the headstock 5 or at a position 90 degrees to the rear of the paper, and a linear guide for guiding the guide projections is provided on the inner surface of the housing 50. Grooves 49, 49 are formed. An air or hydraulic cylinder 51 is attached to an upper portion of the housing 50, and the cylinder 51 and the U-shaped bearing 44 are connected by a rod 52. When the cylinder 51 is operated, the L-shaped connecting member 47 is moved to the linear guide groove 4.
The rotary dresser 40 and the motor 46 also move up and down at the same time. The lowering amount of the rotary dresser 40 due to the vertical movement may be adjusted by a bar micrometer (not shown) or the like.

When the L-shaped connecting member 47 slides down the linear guide grooves 49, 49, the polishing cloth 7 of the polishing disk 8 fits into the groove 42 (FIG. 10) of the rotary dresser 40 and a predetermined amount of time. Contact with pressure. In this state, the polishing cloth 7 is dressed while the rotary dresser 40 is rotated by the motor 46.

As described above, the rotary dresser 4 is attached to the headstock 5.
Since 0 is interlocked, dressing of the polishing pad 7 can be performed by the rotary dresser 40 while mirror polishing the wafer notch with the polishing disk 8. When dressing is not necessary, the cylinder 51
Is operated to raise the rotary dresser 40, and the polishing cloth 7 and the rotary dresser 40 are separated.

As described above, even if the housing 50 is not connected to the headstock 5 so that the rotary dresser 40 moves up and down, the headstock 5 can be moved to a position on the headstock that does not interfere with other members of the processing apparatus, such as the motor 1. If so, the housing 50 can be fixed at an arbitrary peripheral position of the headstock 5 and can be implemented. As described above, when the housing 50 is mounted at a position 90 degrees from the top of the headstock 5 in the circumferential direction, the housing 50 is mounted on the top of the headstock 2 and the rotary dresser 40 is mounted.
The dressing can be performed by bringing the rotating dresser 40 into contact with the polishing pad 7 from any circumferential direction, in addition to moving the polishing pad up and down.

In the above embodiments, the notch chamfered portion is mirror-polished by tilting the wafer. Instead of tilting the wafer, a polishing disk or a polishing belt is moved so as to contact the notch chamfered portion. It is also possible to carry out. Also, without setting the weight 19 to a fixed weight, a plurality of divided weights are stacked and attached,
The pressing force of the polishing cloth against the notch is adjusted by changing the weight of the weight by adding or subtracting as needed. Further, instead of the load means including the weight, the headstock mounting base 13 may be biased by a fluid cylinder.

[0046]

According to the notch mirror processing apparatus of the present invention,
The mirror-finished portion of the notch can be pressed and contacted toward the rotation center of the polishing disk, and further, the machining inclination angle, the rotation speed of the disk-shaped mirror-finished surface, the rotation direction, and the load of the load unit can be arbitrarily adjusted. Therefore, it is possible to provide a notch mirror processing apparatus capable of easily performing the mirror finishing of the notch and improving the yield.

The use of the polishing belt and the polishing tape simplifies the mechanism of the processing apparatus, and facilitates replacement of the mirror processing means to a polishing disk or a polishing belt depending on the type of wafer. It is possible to provide a mirror finishing device for a wafer notch portion that can be performed. Furthermore, by attaching a rotating dresser, dressing of the polishing pad can be performed at any time during or after mirror finishing.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of a notch mirror processing apparatus of the present invention.

FIG. 2 is a plan view of a main part of a wafer chuck table and a notch portion mirror surface processing means in the embodiment of the present invention.

FIG. 3 is a front view of a main part of a wafer tilting mechanism according to the embodiment of the present invention.

FIG. 4 is a side view of a main part of the wafer tilting mechanism according to the embodiment of the present invention.

FIG. 5 is an explanatory view when a wafer notch and a wafer notch are mirror-finished;

FIG. 6 is a front view of a main part of another embodiment of the present invention.

FIG. 7 is a view showing a polishing belt and a polishing tape used in another embodiment of the present invention.

FIG. 8 is an explanatory diagram of a polishing belt pressing member.

FIG. 9 is a front view of a main part of another embodiment of the present invention to which a rotating dresser is attached.

FIG. 10 is an explanatory view of a rotary dresser used in the present invention.

[Explanation of symbols]

5. Headstock 6. Spindle 7. Polishing cloth 8.
・ Polishing disk 10 ・ ・ Wafer 12 ・ ・ Wafer chuck table 1
4. Slide means 24 Rotating plate for tilting wafer 27 Slit 30 Polishing belt 30a Polishing tape 35 Polishing belt pressing member 35a Polishing tape pressing member 40 Rotary dresser

Claims (1)

[Claims] 1. A dresser comprising diamond grooves for dressing polishing means in grooves formed on the outer periphery of a rotatable ring-shaped mount.