JP2832149B2 - Polishing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polishing apparatus, and more particularly, to a polishing apparatus for polishing a chamfer on the outer periphery of a wafer.

[0002]

2. Description of the Related Art In a single crystal silicon wafer or a compound semiconductor wafer (hereinafter, referred to as a wafer), a chamfered portion is formed by grinding an outer peripheral portion thereof. When the chamfered portion is formed on the wafer in this way, cracking or chipping from the chamfered portion can be prevented during handling or alignment, but generation of fine powder cannot be prevented. Therefore, there is a risk that the yield and reliability of semiconductor device production may be reduced due to the fine powder.
Therefore, conventionally, after the chamfering of the wafer, the chamfered portion is polished.

In this polishing, polishing is performed by pressing a rotating polishing buff against a chamfered portion of a wafer. At that time, a polishing agent (colloidal silica) in which colloidal silica or the like is dispersed in an alkaline solution is used. Abrasive grains) are supplied to the polishing section.

However, when the polishing agent is supplied to the polishing portion, the polishing agent is also applied to portions other than the polishing portion (for example, the front and back surfaces of the wafer), and the portion is damaged by the etching action of the alkali. This flaw cannot be removed in a cleaning step for cleaning the abrasive. Nevertheless, the scratch on the wafer surface is removed by mirror polishing performed later, so there is no problem, but the scratch left on the back surface of the wafer remains in the product as it is, and this becomes a source of new fine powder, thereby Inconveniences such as a yield at the time of device manufacturing and deterioration of characteristics of the semiconductor device occur.

In recent years, as a polishing apparatus for polishing without using an abrasive, an apparatus for polishing a chamfered portion of a wafer by using a tape carrying fixed abrasive grains has been considered. This apparatus does not use a polishing agent containing alkali, so that there is no problem of scratches on the back surface of the wafer. However, in the case of a tape carrying fixed abrasive grains, unlike free abrasive grain polishing, the abrasive grains are not replaced on the working surface, so if the same surface of the tape is used repeatedly, the fixed abrasive grains will wear or clog. Will occur. Therefore, in order to polish the chamfered portion efficiently, it is necessary to successively apply new surfaces of the tape to the chamfered portion. For that purpose, in a polishing apparatus using a tape carrying fixed abrasive grains, a new surface of the tape is fed out by a reel for feeding out, the used surface is polished, and the used portion is sequentially wound by a winding reel. Ingenuity is taken such as taking.

FIG. 6 shows an outline of the polishing apparatus. The polishing apparatus 11 includes a wafer holding means 12 for holding a wafer W, a pressing member 13 for pressing a tape T against a chamfered portion of the wafer W to be polished, a feeding reel 14 for feeding out the tape T, and a tape T And a take-up reel 15 for taking up a used portion of the reel. In this apparatus 11, the tape T is fed by the feeding reel 14, the fed tape T is pressed against the chamfered portion of the wafer W by the pressing member 13, the polishing is performed on the new surface of the tape T, and the used portion is sequentially processed. During the polishing, the tape T itself is slightly swung in the width direction, and the wafer W held by the wafer holding means 12 is rotated to polish the wafer W during polishing. A relative speed is provided between the chamfer and the tape.

[0007]

However, this polishing apparatus has the following problems.

When polishing is performed with the tape T, the new surface feeding speed of the tape T and the relative speed between the chamfered portion and the tape T in the polishing portion are important factors in performing good polishing. In the polishing device 11, the winding speed of the tape T can be changed arbitrarily, and therefore, the new surface feeding speed of the tape T can be changed. However, since the tape T is used in the width direction due to vibration in the tape width direction, While it is difficult to effectively use the entire surface, and when the wafer W is rotated at a high speed to obtain a relative speed, there is a concern that vibration due to the eccentricity of the wafer W with respect to the rotation axis may occur, Excessive polishing may be performed. Also,
When feeding out a new surface of the tape T, if the rotation speed of the take-up reel 15 is kept constant, the tape supply speed (new-surface take-out speed) increases with an increase in the tape winding amount of the take-up reel 15. Therefore, there has been a problem that polishing conditions become non-uniform and stable polishing cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a polishing apparatus capable of performing good polishing stably and quickly.

[0010]

The first means comprises a reel for reeling out a tape having fixed abrasive grains carried on its surface and reeling out the tape, and a tape reel for reeling out the reel. A take-up reel, a rotary drum having both reels detachably installed therein, and a midway portion of the tape wound around the two reels spirally wound around the outer periphery; rollers, and a tape speed control means configured to include a pressing roller for pressing the tape before winding to the governor roller, a motor for rotating the rotary drum, the winding
Support reel and can be rotated integrally with the take-up reel
Another motor for rotating a support shaft (reel support shaft) is provided. A take-up reel can be attached to the reel support shaft in a half-clutch state. The drive shaft is directly or indirectly connected by a gear mechanism.

The second means is a reel for reeling out a tape having a surface on which fixed abrasive grains are carried, and reeling out the tape, and a reel for winding up the tape reeled out from the reel for reeling out. A rotating drum around which an intermediate portion of the tape wound around the reels is spirally wound around the outer periphery, and a speed control roller; And a tape speed control means including a press roller for pressing the tape before winding on the speed control roller, a motor for rotating the rotary drum, and a drive shaft (roller drive shaft) of the speed control roller. rotate a another motor that obtained by rotating the governor roller, its supports reel the winding
The take-up reel can be mounted in a half-clutch state on a support shaft (reel support shaft) that can rotate integrally with the take-up reel . Directly between the roller drive shaft and the reel support shaft, It is connected, either directly or indirectly, by a gear mechanism.

[0012]

According to the above-described means, the tape is wound around the rotating drum, and the tape moves relative to the object to be polished by rotation of the take-up reel. The new part of will come into contact with the object to be polished, and by the rotation of the rotating drum,
Sufficient relative speed between the chamfer and the tape will be obtained. As a result, stable polishing can be performed.

The speed control roller that holds the tape between the press roller and the press roller is forcibly rotated by a motor, while the take-up reel mounted on the reel support shaft in a half-clutch state is speed-controlled by the tape speed control means. Since the tape is merely wound up sequentially, in the case where the tape is continuously supplied and the polishing is performed, if the rotational speed of the speed control roller is kept constant, the tape supply speed can be kept constant. Therefore, stable polishing can be performed. In the case where the tape is supplied intermittently, if the number of rotations of the speed control roller during the supply of the tape is kept constant, the supply amount of the tape can be kept constant. Therefore,
The tape can be used without waste, and the life of the tape can be easily managed. In other words, when the tape supply speed and the tape supply amount are to be controlled by keeping the rotation speed and the number of rotations of the take-up reel constant, as the tape take-up amount of the take-up reel increases, However, the tape supply speed and the tape supply amount increase, and stable polishing cannot be performed or the tape is wasted. However, according to the above-described means, it is necessary to keep the rotation speed and the number of rotations of the governing roller constant. As a result, the tape supply speed and the tape supply amount are controlled, so that the tape supply speed and the tape supply amount can always be kept constant, stable polishing can be performed, and waste of the tape can be prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A polishing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an external perspective view of a polishing apparatus according to an embodiment. The polishing apparatus 1 includes a rotating drum 2, a reel 3 for feeding (FIG. 2) and a winding reel 4 (FIG. 2) installed in the rotating drum 2, and a motor ( A first motor) 5 and a motor (second motor) 6 for rotating the take-up reel 4 are provided. Then, the tape T fed from the reel 3 for feeding is spirally wound around the outer peripheral surface of the rotary drum 2 and then wound on the reel 4 for winding.

Here, the tape T will be described. As shown in FIG. 3, the tape T is obtained, for example, by bonding fixed abrasive grains 72 on a tape base 70 via an adhesive 71. The fixed abrasive grains 72 are wound around the reel 3 so that the surface on which the fixed abrasive grains 72 are formed faces outward. Although not shown, the tape T may be of a type in which a paint in which fixed abrasive grains are mixed is applied on a tape base material.

Next, the rotary drum 2 will be described.
As shown in FIG. 2, the rotary drum 2 includes a cylindrical body 20, a bottom plate 21 and a top plate 22 which are detachably attached to the upper and lower sides of the cylindrical body 20, and a partition plate provided inside the cylindrical body 20. The inside of the rotary drum 2 is divided into three parts, a lower chamber 20a, a middle chamber 20b, and an upper chamber 20c, by 23 and 24.

The rotary drum 2 is fixed to a motor shaft 5a of a motor 5. That is, in this embodiment, the motor shaft 5a of the motor 5 is a support shaft of the rotary drum 2. A motor 6 is fixedly provided on a motor shaft 5 a of the motor 5. The motor shaft 6a of the motor 6 extends through the motor shaft 5a and the bottom plate 21 and the partition plates 23 and 24 of the rotary drum 2. The motor shaft 6a has a base shaft 60,
The connecting shaft 61 is detachably connected to the base shaft 60. The base shaft 60 and the connecting shaft 61 are connected in the lower chamber 20 a of the rotating drum 2. The base shaft 60 and the connecting shaft 61 are connected by, for example, a spline. The reel 3 for feeding is attached to the base shaft 60 of the motor shaft 6a so as to be able to run idle. The reel 3 for feeding is a cylinder 2
0 is removed from the bottom plate 21 and attached to the base shaft 60 with the connecting shaft 61 removed from the base shaft 60.
Further, a large diameter spur gear 61 a is attached to the joint shaft 61 at a portion located in the middle chamber 20 b of the rotary drum 2. Further, the take-up reel 4 is attached to the joint shaft 61 at a portion located in the upper chamber 20c of the rotary drum 2 in a half-clutch state. That is, in this embodiment, the motor shaft 6a of the motor 6 is a support shaft of the winding reel 4, and the motor shaft 6a (joint shaft 61) is attached with the bush 63 via the O-ring 62. The winding reel 4 is mounted on the bush 63. The winding reel 4
In the state where the top plate 22 is detached from the cylindrical body 20,
Attach to 1.

The rotary drum 2 (specifically, the cylindrical body 2)
0), the rotating drum 2 as shown in FIG.
Slits 25a and 25b which are inclined with respect to the generatrix are provided respectively, and the tape T fed from the feeding reel 3 is once guided to the outside of the rotary drum 2 and spirally wound thereon, and then again inside the rotary drum 2. To be taken up by the take-up reel 4.

Further, in the upper chamber 20c of the rotary drum 2,
As shown in FIG. 4, the guide roller 30 and the speed control roller 31
Is installed. The shaft (roller drive shaft) 31a of the speed control roller 31 penetrates through the partition plate 24 and the middle chamber 20b.
A small-diameter spur gear 33 that meshes with the large-diameter spur gear 61a is attached to a portion facing the middle chamber 20b. As a result of the engagement of the large-diameter spur gear 61a and the small-diameter spur gear 33, the motor 6 forcibly rotates the speed control roller 31.

The upper chamber 20c of the rotary drum 2 is provided with a tape speed control means 40 for controlling the speed of movement of the tape T between itself and the speed control roller 31. This tape speed control means 40 includes a pair of arms 41 as shown in FIGS.
42, each of which has a shaft 41
a and 42a. A "L" shaped seesaw plate 43 is attached to the tip of one arm 41. Pressing rollers 44a and 44b capable of simultaneously contacting the speed control roller 31 are attached to both ends of the seesaw plate 43. On the other hand, a support roller 45 for supporting the speed adjusting roller 31 from the side opposite to the pressing rollers 44a and 44b is provided at the tip of the other arm 42. This arm 4
A pressing force adjusting device 46 for adjusting the pressing force of the tape T by the pressing rollers 44a, 44b
Is attached. The pressing force adjusting device 46 includes a bolt 46a having a base end fixed to the arm 42 and a distal end inserted into a bolt hole 41b of the arm 41, a nut 46b screwed to the bolt 46a, the nut 46b and the arm 41 and a spring 46c interposed therebetween. And in this pressing force adjusting device 46,
By operating the nut 46b, the urging force of the spring 46c is adjusted.
The pressing force of the tape T by 4b is adjusted.

On the other hand, the wafer holding mechanism 8 attached to the polishing apparatus 1 will be described with reference to FIG. 1. The wafer holding mechanism 8 includes a suction unit 80 for vacuum-suctioning the wafer W, A motor (not shown) for rotating the supported wafer W, and an air cylinder 82 for operating a suction unit 80 and a stage 81 supporting the motor are provided. The suction unit 80, the motor, the stage 81, and the air cylinder 82 have a planar shape of “T”.
It is attached to a frame 83 formed in a letter shape.
At the center of the frame 83, a stage 81 is mounted so as to be slidable in a direction approaching / separating from the rotary drum 2. Further, both wing tip portions of the frame 83 are erected, and one of the erected portions is connected to the bearing 84 and the other is connected to the motor 85. The bearing 84 and the motor 8
Reference numeral 5 substantially exists on a tangent line which is in contact with the contact point between the wafer W and the rotary drum 2, and rotates about the shaft 86. According to such a wafer holding mechanism 8, the wafer chamfered portion can be reliably pressed against the tape T at a predetermined interval.

Next, a method of using the polishing apparatus 1 of this embodiment will be described.

First, the reel 20 for feeding is attached to the base shaft 60 with the cylinder 20 removed from the bottom plate 21 and the connecting shaft 61 removed from the base shaft 60. Then, the tubular body 20 is attached to the bottom plate 21, and the connecting shaft 61 is connected to the base shaft 60. At this time, the tip of the tape T wound on the reel 3 is pulled out from the slit 25a of the cylindrical body 20 in advance. Next, the top plate 22 is removed, and the take-up reel 4 is attached to the joint shaft 61. After the tape T is spirally wound around the outer periphery of the rotary drum 2, the tape T is guided into the upper chamber 20 c of the rotary drum 2 through the slit 25 b of the cylindrical body 20, and is guided from the guide roller 30 to the speed control roller 31. Then, the tip of the tape T is attached to the take-up reel 4 after being sandwiched between the pressing roller 44a and the pressing roller 44b. Next, the top plate 22 is attached to the cylindrical body 20, and the motor 6 is driven to remove the slack of the tape T.

On the other hand, the wafer W is sucked by the suction portion 80 of the wafer holding mechanism 8, and
The chamfered portion of the wafer W is brought into contact with the tape T wound around the outer periphery of the rotating drum 2. In this contact, it is preferable that the rotating drum 2 be rotated by the motor 5, the wafer W be rotated by the motor (not shown), and the tape T be moved by the motor 6. The rotation direction of the rotary drum 2 and the tape T
It is desirable to keep the moving direction of the same.

In this manner, polishing is performed by bringing the tape T into contact with the chamfered portion. In this case, the shaft 8 is
The wafer W is rotated around the wafer 6 in order to move the polished portion of the wafer W in the circumferential direction of the wafer W while rotating the wafer W around the center. In addition, the tape T is caused to move by driving the motor 6. In this case, the moving speed of the tape T is kept constant by controlling the rotation speed of the governing roller 31, but the moving speed of the tape T fed by the governing roller 31 is
The tape winding speed of the winding reel 4 in a state where the tape T is not wound at all and does not slide with respect to the connecting shaft 61 is set to be equal to or slightly lower than the tape winding speed.

According to the polishing apparatus 1 configured as described above, the tape T is spirally wound around the rotary drum 2, and the tape T is moved by the rotation of the take-up reel 4. The new surface of the tape T is successively fed out, and the rotation of the rotary drum 2 provides a sufficient relative speed between the chamfered portion and the tape. Therefore, good polishing can be stably performed. Further, since the tape T is spirally wound around the rotary drum 2, the contact portion with the chamfered portion of the wafer W shifts obliquely across the tape T with the rotation of the rotary drum 2. Furthermore, since the tape T is slowly wound up, the tape T is shifted to the new surface side at a fine pitch, so that the entire surface of the tape T can be used effectively.

The speed control roller 31 for sandwiching the tape T between the pressing rollers 44a and 44b is forcibly rotated by the motor 6, while the winding reel 4 attached to the connecting shaft 61 in a half-clutch state is required. Slides with respect to the connecting shaft 61 in accordance with. That is, when the supply speed of the tape T of the speed adjusting roller 31 becomes slower than the winding speed of the winding reel 4, the winding reel 4 slides with respect to the joining shaft 61, and the tape speed adjusting means. Since only the tapes T controlled by 40 are wound sequentially, the supply speed of the tapes T depends only on the rotation speed of the speed control roller 31. As a result, if the rotation speed of the speed adjusting roller 31 is kept constant, the supply speed of the tape T can be kept constant. Therefore, stable polishing can be performed.

Although the embodiments made by the inventor have been described above, the present invention is not limited to the embodiments, and it is a matter of course that various modifications can be made without departing from the gist of the invention. .

For example, in the above embodiment, the motors 5 and 6 are provided on the bottom plate 21 side of the rotary drum 2.
May be provided on the top plate 22 side. In this case, the support shaft (joint shaft 61) of the take-up reel 4 passes through the support shaft of the rotary drum 2 (motor shaft 5a of the first motor 5). You don't have to.

In the above embodiment, the support shaft (joint shaft 61) of the winding reel 4 directly driven by the motor 6 is used.
The drive shaft 31a of the speed control roller 31 is connected to the speed control roller 31 via a gear mechanism. Conversely, the drive shaft 31a of the speed control roller 31 is directly driven by the motor 6,
The take-up reel 4 may be connected to the drive shaft 31a via a gear mechanism. The consolidation in this case is
It may be direct or indirect.

In the above-described embodiment, the polishing is performed while the tape T is continuously supplied.
Without continuously supplying the tape T, the wafer W is rotated by the elevating means while the wafer W is rotated, and the wafer W is relatively moved in the generatrix direction of the rotary drum 2 to perform polishing. The present invention is also applicable to a device in which the old tape T is wound at a time after the entire surface of the tape T has been used, and the entire surface of the tape T exposed to the outside is newly polished as a new surface. Applicable. In this case, since the number of rotations of the governing roller 31 required to make the entire surface of the tape T exposed to the outside a new surface is always constant, the entire surface of the tape T exposed to the outside is newly fixed. As a result, it is possible to avoid extra supply of the tape T, and it is possible to use the tape T without waste, and it is easy to manage the tape life.

[0033]

According to the present invention, a reel on which a tape having fixed abrasive grains carried on its surface is wound and held, and a payout reel for feeding the tape, and a take-up for winding up the tape fed from the payout reel And the two reels are detachably installed inside, and the middle part of the tape wound around the two reels is spirally formed on the outer periphery.
A tape rotating means including a rotating drum wound in a shape, a speed controlling roller, and a press roller for pressing the tape before winding on the speed controlling roller; and a motor for rotating the rotating drum. Supports the take-up reel
And a motor for rotating a support shaft (reel support shaft) that can rotate integrally with the take-up reel, and the take-up reel can be attached to the reel support shaft in a half-clutch state. Since the reel support shaft and the drive shaft of the speed governing roller are directly or indirectly connected by a gear mechanism, new portions of the tape are successively brought into contact with the workpiece. At the same time, the rotation of the rotary drum provides a sufficient relative speed between the chamfer and the tape. As a result, stable polishing can be performed.

Further, while the speed adjusting roller for sandwiching the tape between the pressing roller and the pressing roller is forcibly rotated by the motor, the winding reel merely winds the tape adjusted by the tape speed adjusting means sequentially. In the case where polishing is performed by continuous supply, if the rotation speed of the speed control roller is kept constant, the supply speed of the tape can be kept constant. Therefore, stable polishing can be performed. Further, in the case where the tape is intermittently supplied, if the number of rotations of the speed control roller at the time of the supply is kept constant, the supply amount of the tape can be kept constant. Therefore, the tape can be used without waste, and the management of the life of the tape becomes easy.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view illustrating a configuration of a rotary drum according to an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a tape according to an embodiment of the present invention.

FIG. 4 is a plan view of the rotary drum according to the embodiment of the present invention with a top plate removed.

FIG. 5 is a perspective view of a pressing device according to the embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a conventional polishing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polishing apparatus 2 Rotary drum 3 Reel for feeding 4 Reel for winding 5, 6 Motor 5a Motor shaft (supporting shaft of rotating drum) 6a Motor shaft (supporting shaft of winding reel) T Tape W Wafer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuka Kuroda 150 Odaikura Osaikura, Nishigo-mura, Nishishirakawa-gun, Fukushima Prefecture Inside the Semiconductor Shirakawa Research Laboratory, Shin-Etsu Semiconductor Co., Ltd. No. Fujiuchi Machinery Co., Ltd. (72) Inventor Yasuo Inada 1650 Kiyono, Matsushiro-machi, Nagano City, Nagano Prefecture Fujitsu Machinery Co., Ltd. (56) References JP-A-61-125765 (JP, A) Kaihei 1-1101758 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B24B 21/00 B24B 9/00 B24B 47/12

Claims (2)

(57) [Claims] 1. A reel for reeling out a tape having a surface on which fixed abrasive grains are carried, and a reel for reeling out the tape, a reel for winding up the tape reeled out from the reel for reeling out, A rotating drum in which a reel is detachably installed inside, and a middle part of the tape wound around the two reels is spirally wound around the outer periphery; a speed control roller; A tape speed control means including a pressing roller for pressing the previous tape; a motor for rotating the rotary drum; and a reel for supporting and winding the reel for winding.
A reel and another motor for rotating a support shaft (reel support shaft) that can rotate integrally with the reel, and a take-up reel can be attached to the reel support shaft in a half-clutch state; And a drive shaft of the speed control roller is directly or indirectly connected by a gear mechanism. 2. A reel for reeling out a tape having a fixed abrasive grain carried on its surface and reeling out the tape, a reel for winding up the tape reeled out from the reel for reeling out, A rotating drum in which a reel is detachably installed inside, and a halfway portion of the tape wound around the two reels is spirally wound around the outer circumference; a speed control roller; Tape speed control means including a pressing roller for pressing the previous tape, a motor for rotating the rotary drum, and a drive shaft (roller drive shaft) of the speed control roller
And a another motor to rotate that obtained by rotating the governor roller, the take-Li for up to support the reel the winding
The take-up reel can be mounted in a half-clutch state on a support shaft (reel support shaft) that can rotate integrally with the roller, and a gap between the roller drive shaft and the reel support shaft is provided.
A polishing apparatus, which is directly or indirectly connected by a gear mechanism.