JP2005186176A - Wafer end face polishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer end face polishing device, easily shaping the end face of a wafer even if the end face is shaped unsymmetrical and simplifying the configuration of the device. <P>SOLUTION: This wafer end face polishing device 10 includes: a wafer rotating mechanism 3 supporting a wafer 12 formed substantially disc-like and rotating the wafer around the axis; and a tape transfer mechanism 18 for transferring a polishing tape 16 guided by a pair of rollers 501, 502 provided in positions for clamping the rotating surface of the wafer supported by the wafer rotating mechanism 14 in the direction of crossing the rotating surface of the wafer, wherein the polishing tape is brought into sliding contact with the end face of the rotating wafer to polish the end face of the wafer. The paired rollers 501, 502 are respectively moved in the direction of coming close to and separating from the waver end face 23 independently. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wafer end surface polishing apparatus that polishes an end surface of a wafer by bringing a polishing tape into sliding contact with the end surface of the wafer.

Various apparatuses for polishing an end face of a wafer have been developed. FIG. 8 shows an example of a conventional wafer end surface polishing apparatus.
A wafer end surface polishing apparatus 100 shown in the drawing is an apparatus that rotates a wafer 102 and polishes the end surface 103 of the wafer 102 by sliding contact with a polishing tape 104. The polishing tape 104 of the apparatus 100 is guided by a drive roller 106 and a guide roller 108 in a direction perpendicular to the rotation surface of the wafer 102 and is fed at a constant speed in the direction of arrow A. The wafer 102 is polished by pressing the end surface 103 against the polishing tape 104. When the pressing is performed, the polishing tape 104 is bent following the shape of the end surface 103 of the wafer 102. 103 is polished in a round shape.
JP-A-7-193030

By the way, in recent years, since there is a demand for downsizing of semiconductor devices, after processing the surface of a semiconductor wafer (see FIG. 9A), processing to form a thin wafer by grinding the back side is performed. (See FIG. 9 (b)).
However, when the wafer is ground on the back surface, a problem that chipping is likely to occur occurs. It has been reported that this problem is not only due to the fact that the wafer is thinly formed, but also that the wafer end surface 103 after the back surface grinding is formed in a knife edge shape.
For this reason, the end surface 103 of the wafer 102 formed in a knife edge shape as shown in FIG. 9B is changed into an arc shape 103a as shown in FIG. 9C (an arc shape symmetrical in the thickness direction of the wafer). It has been proposed that polishing be performed.

  In an experiment conducted under certain conditions, in the case of a knife-edge-shaped end face, the impact breaking load for breaking the wafer was 5.6 N, whereas when the wafer having the same thickness was end-polished in an arc shape The impact fracture load was 43.8 N, and the benefit of polishing the end face in a circular arc shape was remarkable.

  However, the above-described apparatus 100 is mainly used for polishing the end surface of a wafer whose end surface shape is symmetrical in the thickness direction, and is not suitable for polishing the end surface 103 having a knife edge shape in an arc shape. is there. Conventionally provided wafer end surface polishing apparatuses are large-scale apparatuses in order to efficiently grind the end surfaces of wafers.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a wafer end surface polishing apparatus that can easily adjust the shape of the end face of a wafer even when the end face has an asymmetric shape, and the apparatus configuration is simplified. There is to do.

The present invention has the following configuration in order to achieve the above object.
That is, a wafer rotating mechanism that supports a wafer formed in a substantially disc shape and rotates the wafer around an axis, and a pair of rollers provided at a position sandwiching the rotating surface of the wafer supported by the wafer rotating mechanism. In the wafer end surface polishing apparatus, comprising a tape transfer mechanism that is guided to transfer the polishing tape in a direction across the rotation surface of the wafer, and polishes the end surface of the wafer by sliding the polishing tape against the end surface of the rotating wafer. Each of the pair of rollers is independently provided so as to be movable in a direction in which the roller contacts and separates from the wafer end surface.

Further, the tape transfer mechanism is supported by a moving table that is movable in a direction of moving toward and away from the wafer end surface on the base, and on the end surface of the wafer held by the wafer rotating mechanism fixed on the base, The polishing tape is provided so that the polishing tape can be contacted and separated while maintaining the inclination of the polishing tape. Thus, the degree of pressing between the wafer end surface and the polishing tape can be adjusted by the moving table, or the wafer end surface and the polishing tape can be brought into contact with or separated from each other.
The tape transfer mechanism is supported by a support member fixed to the movable table in a state where each of the pair of rollers protrudes from the support member, and at least one of the pair of rollers is supported by the support member. The protrusion amount from the member is variably provided.

  In the present invention, each of the one and the other rollers is provided so as to be able to move independently in the direction of contact with and away from the wafer end surface, so that the polishing tape guided by the one roller and the other roller can be inclined. It can be changed freely. For this reason, since the inclination of the polishing tape to be brought into sliding contact with the wafer end surface can be adjusted and the protruding portion of the wafer end surface can be intensively polished, the shape of the wafer end surface can be efficiently polished into a smooth curved surface, etc. Remarkably effective.

Preferred embodiments of a wafer end surface polishing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a side sectional view showing a configuration of an embodiment of a wafer end surface polishing apparatus according to the present invention. The wafer end surface polishing apparatus 10 according to the present embodiment is disposed at a position facing a wafer rotating mechanism 14 that supports a substantially disk-shaped wafer 12 and rotates it around the axis of the wafer 12, and an end surface 13 of the wafer 12. And a tape transfer mechanism 18 for transferring the polishing tape in a direction crossing the rotation surface of the wafer 12, and the polishing tape 16 is brought into sliding contact with the end surface 13 of the rotating wafer 12 to polish the end surface 13 of the wafer 12.
In the present embodiment, the wafer rotation mechanism 14 is fixed on the base 20, and the tape transport mechanism 18 is supported by the moving table 27 on the base 20 and is provided so as to be movable. Thus, the polishing tape 16 can be brought into contact with and separated from the end face 13 of the wafer 12 supported by the wafer rotating mechanism 14 by moving the tape transfer mechanism 18 by the moving table 27.

  The wafer rotating mechanism 14 is provided with a rotating shaft 24 that extends in the vertical direction and is rotated by a drive motor 22. At the upper end of the rotary shaft 24, an adsorption rotation table 26 that adsorbs and holds the wafer 12 is provided, and is provided so as to rotate the wafer 12 in a horizontal plane.

The tape transport mechanism 18 is movable in the front-rear direction of the apparatus (the left-right direction in FIG. 1, and in this embodiment, the direction in which the tape transport mechanism 18 approaches the wafer 12 is the front), and the X table 28. On the upper side, the table is moved to an arbitrary position on the base 20 by a moving table 27 including a Y table 30 that can move in the left-right direction of the device (in FIG. 1, the front-rear direction) perpendicular to the moving direction of the X table 28. be able to.
In this embodiment, the X table 28 is guided by a guide rail 32 provided on the base 20 and is movably provided by a drive motor 34 and a ball screw 36, and the polishing tape 16 is attached to the wafer end surface 13. It is used when separating. The Y table 30 is guided by a guide rail 38 provided on the X table 28 so as to be moved in the left-right direction by a drive motor (not shown) and a ball screw 40. 13 for positioning in the left-right direction when the abrasive tape 16 is slidably contacted.

On the Y table 30, a tape transfer mechanism 18 for sliding the unused polishing tape 16 on the wafer end surface 13 is provided. The tape transport mechanism 18 is supported by a frame-like support member 53 fixed on the Y table 30, and a feed roller 42 that feeds the polishing tape 16 from the tape roll 48 and the polishing tape 16 passes through a predetermined path. A plurality of guide rollers 50... For guiding and a take-up roller 44 for winding the polishing tape 16 are provided.
In the present embodiment, a feed roller 42 is disposed on the lower side, and a take-up roller 44 is disposed on the upper side. The polishing tape 16 is guided to a position facing the wafer end surface 13 (hereinafter referred to as the head portion 52) by the guide rollers 50. It is provided to be.

A pair of rollers 501 and 502 supported at positions protruding from the support member 53 are guided to the head portion 52 so that the polishing tape 16 is guided to a position facing the wafer end surface 13 and moved in a direction across the rotation surface of the wafer 12. Are provided so as to sandwich the rotating surface of the wafer.
In the present embodiment, one of the rollers is disposed below the rotation surface of the wafer 12 and is provided as a lower variable roller 501 that guides the polishing tape 16 from the delivery roller 42 upward. The other is disposed above the rotation surface of the wafer 12 and is provided as an upper variable roller 502 that guides the polishing tape 16 from the lower variable roller 501 to the take-up roller 44 side.
In the present embodiment, the lower variable roller 501 and the upper variable roller 502 can be independently moved in parallel with the rotating surface of the wafer 12 in the direction of contacting and separating from the wafer end surface 13. Is provided.

  Specifically, the lower variable roller 501 is rotatably provided such that a shaft 501a extending horizontally in the left-right direction of the lower variable roller 501 is supported by the tip of a support arm 54 protruding from a side portion of the support member 53. Since the support arm 54 is provided so as to be linearly movable by a drive motor 56 and an LM (Linear Motion) guide actuator 58, the amount of protrusion from the side of the support member 53 can be made variable and variable downward. It is provided so that the position of the roller 501 can be moved horizontally in the front-rear direction. Also, the upper variable roller 502 is provided in the same configuration as the lower variable roller 501 and is provided so as to be horizontally movable in the front-rear direction of the apparatus 10.

  With the above configuration, the wafer end surface polishing apparatus 10 according to the present embodiment adjusts the amount of protrusion of the lower variable roller 501 and the upper variable roller 502 from the support member 53, respectively, so that the lower variable roller 501 and the upper variable roller 502 Since the inclination angle of the polishing tape 16a (hereinafter referred to as the head surface 16a) can be freely changed, the slidable contact angle of the polishing tape 16 that is slidably contacted with the wafer end surface 13 is appropriately adjusted so that the wafer end surface 13 is moved. Can be polished. Therefore, the protruding portion of the wafer end surface 13 can be concentrated and polished, and the knife edge-shaped wafer end surface 13 can be efficiently formed into an arc-shaped smooth curved surface.

The wafer end surface polishing apparatus 10 of the present embodiment is arranged on the upper side so that the direction of feeding the polishing tape 16 can be fed not only from one direction from the bottom to the top but also from the top to the bottom. The roller 44 is provided as a feed roller, and the roller 42 provided on the lower side is provided as a take-up roller.
Further, in the apparatus 10 of the present embodiment, in order to always provide the polishing tape 16 of the head portion 52 in a state of being tensioned with a predetermined tension, between the feed roller 42 and the lower variable roller 501, and the upper variable roller 502. Tension rollers 60 and 62 are provided between the winding roller 44 and the winding roller 44, respectively. Each of the tension rollers 60 and 62 is provided with a driving roller 64 and a driven roller 66 driven by the driving roller 64 so as to move up and down, and the abrasive tape 16 is interposed between the driving roller 64 and the driven roller 66. By being sandwiched and guided, the polishing tape 16 is always provided with a predetermined tension. The driving rollers 64 of the tension rollers 60 and 62 are set so that only the driving roller 64 on the side close to the winding roller 44 is driven.

Next, an example of processing when the wafer end surface 13 is polished using the apparatus 10 of the present embodiment will be described with reference to FIGS.
First, the semiconductor wafer 12 (see FIG. 9B) having the back surface ground and the end surface 13 provided in a knife edge shape is attached to the suction rotating table 26 by sucking the back surface, and the rotating shaft 24 is driven to drive the wafer. 12 is rotated (the rotation speed of the wafer in this embodiment is 300 to 600 rpm). Then, the unused tape roll 48 is attached to the delivery roller 42, and the delivery roller 42, the take-up roller 44 and the drive roller 64 of the tension roller 62 are driven, and the abrasive tape 16 (the abrasive tape in this embodiment has a particle size of # 1000). (In this embodiment, the transfer speed is 30 to 70 mm / min).

  When the polishing of the wafer end surface is started, first, as shown in FIG. 1, the protrusion amount of the lower variable roller 501 is increased, the protrusion amount of the upper variable roller 502 is decreased, and the head surface 16a of the polishing tape 16 is The front is lowered and tilted. In this state, when the X table 28 is moved forward and slidably contacted with the wafer end surface 13, the polishing tape 16 is provided on the back surface side of the wafer end surface 13 having a knife edge shape, as shown in FIG. The edge portion 13a is slidably contacted with the edge portion 13a, and the edge portion 13a of the end face 13 is polished.

When the corner of the edge portion 13a is polished as shown in FIG. 3 (b), the lower variable roller 501 and the upper variable roller 502 are opposed to each other in the vertical direction as shown in FIGS. 2 and 3 (c). The wafer end surface 13 is polished by providing the head surface 16 a substantially perpendicular to the rotation surface of the wafer 12. As a result, as shown in FIGS. 3B and 3D, the corner portion 13b formed by chamfering the edge portion 13a can be polished to provide the end face 13 in a shape close to an arc.
Thereafter, as shown in FIG. 3 (e), the protrusion amounts of the lower variable roller 501 and the upper variable roller 502 are continuously changed to change the inclination angle of the head surface 16a to be brought into sliding contact with the wafer end surface 13. . As a result, as shown in FIG. 3 (f), the wafer end surface 13 can be polished in a round shape, and the wafer end surface 13 can be formed in an arc shape.

  The degree of pressing of the polishing tape 16 when the polishing tape 16 is brought into sliding contact with the wafer end surface 13 may be appropriately adjusted depending on the thickness of the wafer 12 to be polished and the shape of the end surface 13. The pressing degree can be adjusted by moving the lower variable roller 501 and the upper variable roller 502 in the contact / separation direction of the wafer end surface, or by moving the X table 28.

When the wafer end surface 13 is pressed against the head surface 16a of the polishing tape 16, the head surface 16a is bent at a bending angle θ and polished as shown in FIG. At this time, in the polishing apparatus 10 of the present embodiment, since the protrusion amounts of the lower variable roller 501 and the upper variable roller 502 can be adjusted, the head surface inclined from the upper variable roller 502 toward the wafer end surface 13. The inclination angle (upper inclination angle) θa of 16a and the inclination angle (lower inclination angle) θb of the head surface 16a inclined from the wafer end surface 13 toward the lower variable roller 501 can be independently changed.
That is, as shown in FIG. 5A, when the lower variable roller 501 is fixed and the protrusion amount of the upper variable roller 502 is changed, the upper inclination angle θa is changed to θa1, θa2 while the lower inclination angle θb remains constant. , Θa3 and the tilt angle can be adjusted. Further, as shown in FIG. 5B, when the upper variable roller 502 is fixed and the protrusion amount of the lower variable roller 501 is changed, the lower inclination angle θb is changed to θb1, θb2 while the upper inclination angle θa remains constant. , Θb3 and the tilt angle can be adjusted.

  As shown in FIG. 6, the lower variable roller 501 and the upper variable roller are controlled by a control unit that controls the protrusion amount of the lower variable roller 501 and the upper variable roller 502 in a state where the wafer end surface 13 is in sliding contact with the head surface 16a. When the head surface 16a is moved in the opposite direction, the head surface 16a can be tilted while maintaining the bending angle θ of the head surface 16a.

  As described above, the polishing apparatus 10 of the present embodiment can freely change the bending angle θ of the head surface 16a in sliding contact with the wafer end surface 13, or incline the head surface 16a while maintaining the bending angle θ. be able to. Therefore, the head surface 16a that is slidably contacted with the wafer end surface 13 while the head surface 16a is slidably contacted with the wafer end surface 13 is not required to move the head surface 16a away from the wafer end surface 13 in order to change the tilt angle. The sliding contact angle can be adjusted.

  Note that, as shown in FIG. 7, the wafer 12 is generally provided with an orientation flat 68 (orientation flat) and a notch 70 as a position reference when processing the wafer. When the linear end surface 72 of the wafer 12 provided with the orientation flat 68 and the notch 70 is polished, the wafer 12 is supported on the suction rotary table 26 in a stopped state and polished by friction caused by the transfer of the polishing tape 16. Then, when the arc-shaped end face 13 other than the orientation flat 68 and the notch 70 is polished, the wafer 12 is rotated and polished as described above.

  The wafer end surface polishing apparatus according to the present invention is not limited to the configuration of the apparatus in the present embodiment. For example, in the present embodiment, the wafer rotation mechanism 14 is fixed on the base 20 and the tape transfer mechanism 18 is movably provided on the base 20, but the present invention is not limited to this. Alternatively, the wafer rotation mechanism 14 may be provided so as to be movable on the base 20, and the tape transport mechanism 18 may be fixed to the base 20. Further, the moving mechanism for moving the lower variable roller 501 and the upper variable roller 502 is not limited to that by the drive motor 56 and the LM guide actuator 58, and the positions of the lower variable roller 501 and the upper variable roller 502 can be changed. Any configuration may be used as long as it is provided.

  In the present embodiment, the amount of protrusion of the lower variable roller 501 and the upper variable roller 502 is provided so as to be adjusted. However, the present invention is not limited to this. Even if the protrusion amount of only one of the lower variable roller 501 and the upper variable roller 502 can be adjusted and the other roller is fixed to the support member 53, the head surface 16a can be inclined freely. Can be changed. Even in this case, the lower variable roller 501 and the upper variable roller 502 are provided so as to be movable by the moving table 27 and are provided so that the protruding amount of one of the rollers can be adjusted. Therefore, each roller can be moved independently.

It is side surface sectional drawing which shows the structure of one Embodiment of the wafer end surface grinding | polishing apparatus concerning this invention. It is side surface sectional drawing which shows the change of the state of the wafer end surface grinding | polishing apparatus shown in FIG. FIG. 2 is an enlarged conceptual diagram showing a state of polishing by enlarging a part of the wafer end surface polishing apparatus shown in FIG. 1. FIG. 2 is an enlarged conceptual diagram showing a state of polishing by enlarging a part of the wafer end surface polishing apparatus shown in FIG. 1. FIG. 2 is an enlarged conceptual diagram showing a state of polishing by enlarging a part of the wafer end surface polishing apparatus shown in FIG. 1. FIG. 2 is an enlarged conceptual diagram showing a state of polishing by enlarging a part of the wafer end surface polishing apparatus shown in FIG. 1. It is a top view which shows the structure of a wafer. It is an expanded sectional view which shows a part of conventional wafer end surface polishing apparatus. It is a conceptual diagram which shows the state of the wafer end surface to grind | polish.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wafer end surface polishing apparatus 12 Wafer 13 Wafer end surface 14 Wafer rotation mechanism 16 Polishing tape 18 Tape transfer mechanism 24 Rotating shaft 26 Adsorption rotation table 27 Moving table 52 Head part 53 Support member 54 Support arm 56 Drive motor 58 LM guide actuator 501 Lower variable Roller 502 Upper variable roller

Claims (3)

Guided by a wafer rotation mechanism that supports a wafer formed in a substantially disc shape and rotates the wafer around an axis, and a pair of rollers provided at a position sandwiching the rotation surface of the wafer supported by the wafer rotation mechanism. A wafer transfer device that includes a tape transfer mechanism that transfers the polishing tape in a direction across the rotation surface of the wafer, and that polishes the end surface of the wafer by sliding the polishing tape against the end surface of the rotating wafer.
Each of the pair of rollers is provided so as to be able to move independently in a direction in which the roller comes into contact with or separates from the wafer end surface. The tape transfer mechanism is supported by a moving table that is movable in a direction of contacting and separating from the wafer end surface on the base,
The polishing tape is provided on the end surface of the wafer held by the wafer rotation mechanism fixed on the base so that the polishing tape can be contacted and separated while maintaining the inclination of the polishing tape. The wafer end surface polishing apparatus according to claim 1. The tape transfer mechanism is supported by a support member fixed to the moving table in a state where each of the pair of rollers protrudes from the support member,
The wafer end surface polishing apparatus according to claim 2, wherein at least one of the pair of rollers is provided with a variable amount of protrusion from the support member.

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