JP3366885B2 - Wafer holding mechanism for polishing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer holding mechanism for a polishing apparatus, and more particularly to a wafer holding mechanism for a polishing apparatus that holds a wafer for polishing a chamfered portion on the outer periphery of the wafer. is there.

[0002]

2. Description of the Related Art A polishing apparatus as shown in FIG. 7 is known as a polishing apparatus for polishing a peripheral chamfered portion of a silicon single crystal wafer or a compound semiconductor wafer (hereinafter referred to as a wafer). This polishing apparatus 1 includes a wafer holding means 2 for holding a wafer W, a pressing member 3 for pressing a tape T against a chamfered portion of a wafer W to be polished, a reel 4 for feeding out the tape T,
And a reel 5 for winding up a used portion of the tape T. In this device 1, the tape T is delivered by the delivery reel 4, and the delivered tape T is pressed against the chamfered portion of the wafer W by the pressing member 3.
The tape T is moved in a direction orthogonal to the main surface of the wafer W, polishing is performed on the new surface of the tape T, and used portions are sequentially wound up by the winding reel 5. In the middle, the tape T itself is slightly swung in the width direction, and the wafer W held by the wafer holding means 2 is rotated to give a relative speed between the chamfered portion of the wafer W and the tape.

When the tape T is used for polishing, the feeding speed of the new surface of the tape T and the relative speed between the chamfered portion of the polishing portion and the tape T are important factors for good polishing. . However, in the polishing apparatus 1,
Although the winding speed of the tape T can be arbitrarily changed and the new surface feeding speed of the tape T can be arbitrarily changed, it is difficult to obtain a sufficient relative speed between the chamfered portion in the polishing portion and the tape T. is there. This is because in the polishing apparatus 1, a sufficient relative speed cannot be obtained by swinging the tape T in the width direction, and therefore the wafer W must be rotated at a high speed. This is because there is a concern that vibration may occur due to the eccentricity of the wafer W with respect to the axis, while excessive polishing of the corners of the orientation flat portion may occur.

Although not yet known, in order to solve such a problem, a tape similar to that described above is wound around the outer circumference of the rotating drum, and the chamfered portion of the wafer is wound on the rotating rotating drum tape. A method and a device for pressing and polishing a wafer have been devised (Japanese Patent Application No. 5-34491).
No. 9).

According to this method or apparatus, the tape is wound around the rotating drum, and the tape moves relative to the object to be polished due to the rotation of the winding reel and so on. The new portion of the tape comes into contact with the object to be polished, and the rotation of the rotary drum provides a sufficient relative speed between the chamfered portion and the tape. Further, since the movement of the polishing portion of the wafer in the circumferential direction is performed by the slow rotation of the wafer, there is no problem caused by the eccentricity of the wafer W. As a result, stable polishing can be performed.

[0006]

[Problems to be Solved by the Invention]

According to the polishing apparatus of Japanese Patent Application No. 5-344919, the tape does not bend so much even when the chamfered portion of the wafer is strongly pressed against the tape wound around the outer circumference of the rotary drum. If the chamfer width of the front and back surfaces of the wafer is large, the tape is not contacted with the chamfered portion at one time.
Therefore, in order to polish the chamfered portions on the front and back surfaces of the wafer, it is necessary to tilt the wafer with respect to the rotating drum during polishing.

The present invention has been made in view of the above point, and a polishing apparatus provided with a mechanism for holding a wafer so that the inclination angle of the wafer can be changed and the chamfered portions on the front and back surfaces of the wafer can be polished thoroughly. It is an object of the present invention to provide a holding mechanism for holding a wafer.

[0009]

In order to achieve the above object, the present invention has the following structure for a wafer holding mechanism for a polishing apparatus. That is, the first aspect of the present invention is a wafer for a polishing apparatus that holds the wafer so as to bring the outer peripheral portion of the wafer into contact with the polishing surface of the polishing apparatus when polishing the outer peripheral portion of the wafer to be polished. In the holding mechanism, a wafer suction plate for sucking and holding the wafer, and a supporting member provided with the wafer suction plate and reciprocally rotated about an axis parallel to the main surface of the wafer held by the wafer suction plate. A rotation means for reciprocally rotating the support member, and a motor for rotating the wafer held by the wafer suction plate by rotating the wafer suction plate about a rotation axis perpendicular to the axis of the support member. And a tangent line of the outer peripheral portion of the wafer or a line in the vicinity of the tangent line passing through a contact portion between the polishing surface of the polishing apparatus and the outer peripheral portion of the wafer is the axis of the supporting member, and the axis So that the wafer is reciprocally rotated about the wafer suction plate, the support member, the wafer is offset from the axis in a plane parallel to the plane including the axis, and a direction perpendicular to the parallel plane. It is characterized in that it is biased and attached.

Further, a second invention is characterized in that, in the first invention, the supporting member is formed in an arm shape, and the suction plate is attached to one end side thereof.

In a third aspect based on the first or second aspect, the supporting member is perpendicular to the axis of the supporting member so that the outer peripheral portion of the wafer is pressed against the polishing surface of the polishing apparatus. It is characterized in that a turning means for turning about a turning axis is provided.

Further, a fourth invention is characterized in that, in the third invention, the turning means is constituted by a cylinder device.

In a fifth aspect based on the first to fourth aspects, the rotating means has a worm wheel and a worm that meshes with the worm wheel and rotates the worm wheel by rotation. The central axis of the worm wheel is the above-mentioned axis.

If this is used in a tape-type polishing device, the following structure can be obtained. A first means is a rotary drum around which a tape having fixed abrasive particles carried on its surface is wound around the outer periphery, and an outer peripheral portion of the wafer such that the main surface of the wafer is perpendicular to the rotation axis of the rotary drum. A polishing apparatus having a wafer holding mechanism capable of pressing the tape and rotating the wafer, wherein the wafer holding mechanism includes a wafer suction plate, a motor for rotating the wafer suction plate, and the wafer suction mechanism. A tangent to the tape or a line in the vicinity of the tangent, which passes through a contact portion between the disk and the supporting member that supports the motor, and the tape wound around the rotary drum and the outer peripheral portion of the wafer (hereinafter, the problem is solved. And a rotation means for rotating the support member reciprocally within a range of a rotation angle about the "tangent line" or "line" as an axis. In which and a pivoting means for pivoting the support member about a parallel pivot axis to the ram of the rotary shaft.

A second means is the same as the first means, wherein the rotating means has a worm wheel and a worm that meshes with the worm wheel and rotates the worm wheel by rotation, and a central axis line of the worm wheel. Is the axis line.

A third means is characterized in that, in the second means, the turning axis and the axis line are orthogonal to each other at the center of the worm wheel.

A fourth means is characterized in that, in the first to third means, the turning means is composed of a cylinder device.

[0018]

According to the above-mentioned means, the outer peripheral portion of the wafer is pressed against the tape by rotating the supporting member around the rotating shaft by the rotating means. Further, the tilting angle of the wafer with respect to the rotating drum can be changed by reciprocally rotating the support member about the predetermined axis within a certain rotation angle range by the rotating means. In this case, if the swirling means is a cylinder device, the contact pressure at the time of pressing can be always kept constant by keeping the fluid pressure inside the cylinder constant.

[0019]

DETAILED DESCRIPTION OF THE INVENTION

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 the polishing apparatus of the embodiment. The polishing apparatus 10 includes a rotary drum 11 around which a tape T is wound, and a wafer holding mechanism 12 that holds a wafer W to be polished.

As shown in FIG. 2, the tape T is obtained by adhering fixed abrasive grains 13c on a tape base material 13a via an adhesive 13b. As the tape T, although not shown in the drawing, a tape base material coated with a coating material containing fixed abrasive grains may be used.

As shown in FIG. 3, the rotary drum 11 is composed of a cylinder body 20 having an end plate 20a on one side and a cylinder body 21 having an end plate 21a on one side, which are integrated with each other. . Of these, the dimension of the peripheral wall 20b of the tubular body 20 along the generatrix direction is larger than that of the peripheral wall 21b of the tubular body 21. Further, the peripheral wall 20b of the tubular body 20 has a large diameter on the base end side, and the upper half portion of the small diameter portion connected to the large diameter portion is configured to be fittable inside the tubular body 21, A bearing 23 having a rubber 22 bonded to the outside of the outer ring can be fitted to the outside of the lower half of the small diameter portion. Further, a reel support shaft 24 is erected on the bottom plate 20a of the tubular body 20, and a tape T is wound around the reel support shaft 24 such that the surface on which the fixed abrasive grains 13c are formed is the outer side. The reel 25 is attached so as to be idle and detachable. The bottom plate 20a of the tubular body 20 is fixed to the motor shaft 26a of the motor 26. On the other hand, a motor 27 is provided on the cylindrical body 21, and a motor shaft 27 a of the motor 27 penetrates the end plate 21 a of the cylindrical body 21 and faces the inside of the cylindrical body 21. The motor shaft 27a serves as a reel support shaft, and a winding reel 28 is fixed to a portion of the motor shaft 27a that faces the inside of the cylindrical body 21. As shown in FIG. 1, tape drum slits 11a and 11b that are inclined with respect to the generatrix are provided on the peripheral wall of the rotary drum 11, respectively. After being guided to the outside of the rotating drum 11 and wound in a spiral shape, it can be guided to the inside of the rotating drum 11 again through the tape slit 11b and wound on the winding reel 28.

As shown in FIG. 1, the wafer holding mechanism 12 includes a wafer suction plate 30 for vacuum-sucking the wafer W,
This wafer suction plate 30 (and thus the wafer suction plate 30
A motor 31 for rotating the wafer W) adsorbed on
An arm (support member) 32 that supports the wafer suction plate 30 and the motor 31 is provided.

The arm 32 includes a shaft portion 33 having a circular cross section,
The mounting portion 34 has a rectangular cross section. Of these, the mounting portion 34 is such that the front half portion is biased in the width direction with respect to the rear half portion connected to the shaft portion 33, and has a step difference when viewed from the side,
The configuration is such that the latter half and the first half are connected. A disk-shaped wafer suction plate 30 is attached to the lower surface of the front half of the mounting portion 34, while a cylindrical motor 31 is attached to the upper surface of the front half. The amount of deviation between the rear half and the front half of the mounting portion 34 and the step size are set so that the axis of the shaft 33 is substantially in contact with the outer periphery of the wafer W when the wafer W is sucked by the wafer suction plate 30. Has been done. The arm 32 includes a rotating means 50 and a rotating means 60.
Are linked to.

As shown in FIG. 4 or 5, the rotating means 50 comprises a worm gear 51 and a motor (not shown) capable of rotating the worm gear 51 in the forward and reverse directions. The worm gear 51 is a mechanical box. It is housed in 52. The hourglass-shaped worm wheel 51 a forming the worm gear 51 is fixedly attached to the shaft portion 33 of the arm 32. Then, the shaft portion 33 has a sleeve 54.
Are supported by bearings 56, 56. Further, the sleeve 54 has swivel shafts 53, 53 parallel to the rotary shaft of the rotary drum 11 on the outer circumference thereof.
3, 53 are supported by the mechanical box 52 via bearings 55, 55. On the other hand, the worm 51b that constitutes the worm gear 51 includes a sleeve 54 and a bearing 5
It is attached via 7, 57 and is connected to a motor (not shown) on the outside of the mechanical box 52 via a flexible joint or the like. Therefore, as a result of the worm gear 51 being driven clockwise and counterclockwise by controlling the number of rotations of the motor during normal rotation / reverse rotation, the arm 32 has a rotation angle range around the axis of the shaft 33. It will reciprocate inside. The axis of the shaft portion 33 is orthogonal to the axis of the swivel shaft 53 at the center of the worm wheel 51a, and passes through the contact portion between the tape T wound around the rotary drum 11 and the chamfered portion of the wafer W. Matches the tangent to or near the tangent.

The turning means 60 is composed of an air cylinder device 61, as shown in FIG. The contact plate 6 is attached to the tip of the rod 61a of the air cylinder device 61.
1b is provided, and the arm 3 is provided via the contact plate 61b.
The chamfered portion of the wafer W is brought into pressure contact with the tape T wound around the outer periphery of the rotary drum 11 by swiveling the swivel shaft 2 around the swivel shaft 53. A biasing means (for example, a spring or the like) for constantly pressing the shaft portion 33 of the arm 32 against the contact plate 61b is provided at an appropriate position so that the arm 32 is surely interlocked with the operation of the rod 61a. Has been.

Next, a method of using the polishing apparatus 10 of this embodiment will be described together with the operation of the polishing apparatus 10.

First, the tubular body 20 and the tubular body 21 are separated from each other, the reel 25 for winding the tape T is set on the tubular body 20 side, and the winding reel 28 is placed on the tubular body 21 side. Set. Then, the tip of the tape T wound around the feeding reel 25 is set to the tape slit 11a of the tubular body 20.
It is pulled out from the rotary drum 11 and wound around the outer circumference of the rotary drum 11 in a spiral shape, and then attached to the winding reel 28 through the tape slit 11b of the tubular body 21. Next, the cylindrical body 20 and the cylindrical body 21 are fitted together, and the motor 27 is driven to remove the slack of the tape T.

On the other hand, the wafer W is sucked by the wafer suction unit 30 of the wafer holding mechanism 12, and the air cylinder device 6
The arm 32 is swung around the swivel shafts 53, 53 by 1 to bring the chamfered portion of the wafer W into contact with the tape T wound around the outer circumference of the rotary drum 11. For this contact, it is preferable that the rotating drum 11 be rotated by the motor 26 and the wafer W be rotated by the motor 31, and the tape T be moved by the motor 27. Also, the rotating direction of the rotating drum 11 and the tape T
The moving directions of are not particularly limited, but it is desirable that they be the same.

In this way, the tape T is brought into contact with the chamfered portion of the wafer W and polished. In this case, the worm gear 51 is operated by a motor (not shown) to move the arm 3
The wafer 2 is reciprocally rotated within the range of the rotation angle around the axis of the shaft 33, and the wafer W is tilted with respect to the tape T wound around the rotary drum 11, as shown in FIG. Also,
The rotating drum 11 is rotated at a relatively high speed by the motor 26, and the wafer W is slowly rotated by the motor 31.

According to the polishing apparatus 10 constructed as described above, the arm 32 is rotated about the rotation axis 53 by the rotation means 60.
The chamfered portion of the wafer W is pressed against the tape T by swirling, and the rotating means 50 reciprocally rotates the arm 32 within a certain rotation angle range about a predetermined axis, so that the rotating drum 11 is rotated. Since the tilt angle of the wafer W can be changed, the chamfered portions on the front and back surfaces of the wafer W can be polished thoroughly. Further, an air cylinder device 61 is used as the turning means 60.
Since the contact pressure at the time of pressing can be always kept constant by making the air pressure inside the cylinder constant, excellent polishing can be performed.

The tape T is spirally attached to the rotary drum 11.
Further, since the tape T is moved by the rotation of the winding reel 28, the new surface of the tape T is continuously fed out, and the rotation of the rotary drum 11 causes the tape T to rotate sufficiently. Chamfer and tape T
The relative speed between will be obtained. Therefore, good polishing can be stably performed.

Although the embodiments made by the present inventor have been described above, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. .

For example, in the above embodiment, the air cylinder device 61 is used as the turning means 60, but it goes without saying that a hydraulic cylinder device may be used.

[0035]

According to the present invention, since the tilt angle of the wafer W can be changed, the chamfered portions on the front and back surfaces of the wafer can be polished thoroughly. Further, when the cylinder device is used as the turning means, the contact pressure at the time of pressing can be always kept constant by making the fluid pressure inside the cylinder constant, and good polishing becomes possible.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram of a tape according to an example.

FIG. 3 is a vertical cross-sectional view for explaining the configuration of the rotary drum according to the embodiment.

FIG. 4 is a left side vertical sectional view of a rotating means according to an embodiment.

FIG. 5 is a rear vertical cross-sectional view of the rotating means according to the embodiment.

FIG. 6 is a diagram for explaining the operation of the wafer holding mechanism according to the embodiment.

FIG. 7 is a schematic configuration diagram of a conventional polishing apparatus.

[Explanation of symbols]

10 Polishing equipment 11 rotating drum 12 Wafer holding mechanism 50 rotation means 60 turning means T tape W wafer

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Otani No. 150 Odaira, Odakura, Saigo-mura, Nishishirakawa-gun, Fukushima Prefecture Inside the Shirakawa Laboratory, Shin-Etsu Semiconductor Co., Ltd. (72) Yasuka Kuroda Nishigo-mura, Nishishirakawa-gun, Fukushima Prefecture Odaira, Ohira 150, Shin-Etsu Semiconductor Co., Ltd., Shirakawa Laboratory (56) References JP-A-4-346429 (JP, A) JP-A-7-100748 (JP, A) JP-A-60-242955 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/304 B24B 9/00

Claims (5)

(57) [Claims] 1. A wafer holding mechanism for a polishing apparatus that holds the wafer so that the outer peripheral portion of the wafer to be polished is brought into contact with the polishing surface of the polishing apparatus when polishing the outer peripheral portion of the wafer. A wafer suction plate for sucking and holding the wafer; a supporting member attached to the wafer suction plate; And a motor that rotates the wafer held by the wafer suction plate by rotating the wafer suction plate around a rotation axis perpendicular to the axis of the support member. The tangent line of the outer peripheral portion of the wafer or a line in the vicinity of the tangent line passing through the contact portion between the polishing surface of the polishing apparatus and the outer peripheral portion of the wafer is the axis of the supporting member, and the axis is the center. As the wafer is reciprocally rotated, the wafer suction cups are
Holding of a wafer for a polishing apparatus, wherein the supporting member is attached to the support member so as to be offset from the axis in a plane parallel to the plane including the axis, and to be offset in a direction perpendicular to the parallel plane. mechanism. 2. The wafer holding mechanism for a polishing apparatus according to claim 1, wherein the support member is formed in an arm shape, and the suction plate is attached to one end side thereof. 3. A turning means for turning the supporting member around a turning axis perpendicular to the axis of the supporting member so as to press the outer peripheral portion of the wafer against the polishing surface of the polishing apparatus. The wafer holding mechanism for a polishing apparatus according to claim 1 or 2. 4. The wafer holding mechanism for a polishing apparatus according to claim 3, wherein the turning means is constituted by a cylinder device. 5. The rotating means has a worm wheel and a worm that meshes with the worm wheel and rotates the worm wheel by rotation, and a central axis of the worm wheel is the axis. The wafer holding mechanism for a polishing apparatus according to claim 1, 2, 3, or 4.