WO2024106110A1

WO2024106110A1 - Wafer end surface polishing device

Info

Publication number: WO2024106110A1
Application number: PCT/JP2023/037590
Authority: WO
Inventors: 佳彦番場
Original assignee: 株式会社ナノシステムソリューションズ
Priority date: 2022-11-18
Filing date: 2023-10-17
Publication date: 2024-05-23
Also published as: TW202440269A

Abstract

Provided is a wafer end surface polishing device that makes it possible to give an end surface of a wafer an appropriate shape, even when the gap between a first roller and a second roller in the thickness direction of the wafer is made smaller as compared to in the past. A wafer end surface polishing device according to the present invention comprises a wafer rotation mechanism, a wafer raising/lowering mechanism, a first roller 43, a second roller 44, a roller movement mechanism 25, and a tape transfer mechanism 26. The roller movement mechanism 25 moves one or both of the first roller 43 and the second roller 44 toward an end surface 27a of a wafer 27 that is supported by the wafer rotation mechanism and polishes the end surface 27a of the wafer 27 with a polishing tape 33 that is transferred between the first roller 43 and the second roller 44. The wafer raising/lowering mechanism raises/lowers the wafer 27 and thereby changes the position at which the polishing tape 33 contacts the end surface 27a of the wafer 27 in the thickness direction of the wafer 27. The wafer end surface polishing device determines the height position of the wafer 27 during polishing, the contact/separation state of the first roller 43 and the second roller 44, etc. on the basis of data about the shape of the end surface 27a of the wafer 27 as inspected by a wafer end surface inspection device.

Description

Wafer edge polishing equipment

The present invention relates to a wafer edge polishing device.

In recent years, wafer edge polishing devices have been used to polish the edge of a wafer to remove unwanted films and surface roughness. For example, in a conventional wafer edge polishing device, the wafer is rotated around its central axis as the axis of rotation, and a polishing tape moved in the thickness direction of the wafer is brought into sliding contact with the edge of the wafer, polishing the edge of the wafer into an arc shape (see, for example, Patent Document 1).

In addition, conventional wafer edge polishing devices place a lower variable roller and an upper variable roller at a position that sandwiches the wafer, and transport a polishing tape stretched between the lower and upper variable rollers in the thickness direction of the wafer, with the lower and upper variable rollers each being movable in a direction approaching the wafer's edge. As a result, in the wafer edge polishing device, by individually bringing the lower and upper variable rollers closer to the wafer, the inclination angle of the polishing tape relative to the wafer's edge can be freely changed, and the wafer's edge can be polished to an optimal shape.

JP 2005-186176 A

However, conventional wafer edge polishing devices polish the entire edge of the wafer from the upper corner to the lower corner by changing the position of the lower variable roller and upper variable roller that sandwich the wafer in the thickness direction and changing the inclination angle of the polishing tape relative to the wafer edge, so that the lower variable roller and upper variable roller must be provided in a position to sandwich the wafer so that the entire edge of the wafer is positioned between the lower variable roller and upper variable roller on which the polishing tape is stretched. Therefore, in order to polish the entire edge of the wafer to the optimal shape using conventional wafer edge polishing devices, the gap between the lower variable roller and upper variable roller on which the polishing tape is stretched must be greater than or equal to the wafer thickness, and the entire edge of the wafer must be sandwiched between the lower variable roller and upper variable roller in the wafer thickness direction, which poses the problem of a larger gap between the lower variable roller and upper variable roller in the wafer thickness direction.

This invention was made against the background of the above circumstances, and aims to provide a wafer edge polishing device that can form the edge of the wafer into an appropriate shape even if the gap between the first roller and the second roller in the thickness direction of the wafer is made smaller than in the past.

The wafer edge polishing apparatus according to the present invention comprises a wafer rotation mechanism that supports a wafer and rotates the wafer in a circumferential direction around the central axis of the wafer as a rotation axis, a wafer lifting mechanism that raises and lowers the wafer supported by the wafer rotation mechanism in the central axis direction, a first roller arranged radially outward of the wafer supported by the wafer rotation mechanism, a second roller arranged radially outward of the wafer supported by the wafer rotation mechanism and opposed to the first roller in the thickness direction of the wafer, and a polishing tape wound around the first roller and the second roller is stretched between the first roller and the second roller, and the polishing tape is moved between the first roller and the second roller. The system includes a tape transport mechanism that transports the tape, and a roller movement mechanism that moves each of the first roller and the second roller independently in a direction toward and away from the edge surface of the wafer, and moves the polishing tape in a direction toward and away from the edge surface of the wafer. The roller movement mechanism moves both or either of the first roller and the second roller in a direction toward the edge surface of the wafer supported by the wafer rotation mechanism, and polishes the edge surface of the wafer with the polishing tape being transported between the first roller and the second roller. The wafer lift mechanism lifts and lowers the wafer, thereby changing the position of the edge surface of the wafer that the polishing tape contacts in the thickness direction of the wafer.

In the present invention, the first roller and the second roller each move independently in a direction approaching the wafer edge surface, and the inclination angle of the polishing tape can be changed. In addition, the wafer can be moved in the direction of the central axis by the wafer lifting mechanism. This means that the position where the polishing tape contacts the wafer edge surface can be changed by adjusting the inclination angle of the polishing tape, and the position where the polishing tape contacts the wafer edge surface can also be changed by changing the height position of the wafer edge surface along the central axis. Therefore, even if the entire wafer edge surface is not necessarily positioned between the first roller and the second roller that transport the polishing tape, the entire wafer edge surface can be polished by appropriately changing the height position of the wafer edge surface. Therefore, even if the gap between the first roller and the second roller in the wafer thickness direction is made smaller than before, the wafer edge surface can be formed into an appropriate shape.

1 is a plan view showing a configuration of a wafer processing system having a wafer end surface polishing apparatus according to the present invention. FIG. 2 is a side view showing the configuration of the wafer end surface polishing apparatus. 2 is a side view showing the configuration of a roller group, a roller moving mechanism, and a tape transfer mechanism. FIG. FIG. 4 is a perspective view showing a configuration of a main part of a roller moving mechanism. FIG. 4 is an enlarged side view of a main portion showing the configuration of a first roller and a second roller. FIG. 11 is a side view showing the second sanding operation. FIG. 11 is an enlarged side view of a main part showing a state of a second sanding operation. FIG. 11 is a side view showing a state of a third sanding operation. FIG. 11 is an enlarged side view of a main part showing a state of a third sanding operation. 1 is a side view showing the configuration of a wafer edge polishing apparatus provided with a plate-shaped back pad. 1 is a schematic diagram showing the configuration of a wafer end surface polishing apparatus equipped with a tape switching mechanism for switching between two types of polishing tapes having different roughnesses. 13 is a side view for explaining the configuration of a base plate and a base plate support part of a wafer end surface polishing apparatus according to another embodiment. FIG. 13 is a side view for explaining the configuration of a base plate and a base plate support part of a wafer end surface polishing apparatus according to another embodiment. FIG. FIG. 11 is a side view showing a state of a second sanding operation in another embodiment. FIG. 11 is a side view showing a state of a third sanding operation in another embodiment.

Below, a preferred embodiment of the wafer edge polishing device according to the present invention will be described in detail with reference to the attached drawings. In the following description, the same components are given the same reference numerals, and duplicate descriptions will be omitted.

FIG. 1 is a plan view showing the configuration of a wafer processing system 10 including a wafer edge polishing device 17 according to the present invention. The wafer processing system 10 is equipped with four

cassette stands

11, 12, 13, 14, an orientation flat/notch detection device 15, a wafer edge inspection device 16, a wafer edge polishing device 17, and a transfer machine 18. The four cassette stands 11-14, the orientation flat/notch detection device 15, the wafer edge inspection device 16, and the wafer edge polishing device 17 are arranged in an approximately circular shape with the transfer machine 18 at the center so as to surround the transfer machine 18.

The four cassette stands 11-14 are stands on which wafer cassettes are placed, and are arranged in an arc shape. A wafer cassette stores multiple, roughly disk-shaped wafers. A loader/unloader unit 19 is provided near the four cassette stands 11-14 to receive and eject each of the wafer cassettes.

The transfer machine 18 loads and unloads wafers into and from the wafer cassette, wafer edge inspection device 16, and wafer edge polishing device 17. The orientation flat and notch detection device 15 inspects the position of the orientation flat and notch formed on the edge of the wafer. The inspection results obtained by the orientation flat and notch detection device 15 are used as information when aligning the orientation flat and notch when storing the wafer in the wafer cassette, and when positioning the orientation flat and notch in the wafer edge inspection device 16 and wafer edge polishing device 17.

The wafer edge inspection device 16 inspects the shape of the wafer edge and outputs the inspection results to the wafer edge polishing device 17. Based on the inspection results received from the wafer edge inspection device 16, the wafer edge polishing device 17 polishes the wafer edge, for example, into a cross-sectional arc shape. The wafers whose edge has been polished are then cleaned. After cleaning, the wafers are dispensed into the wafer cassettes placed back on the cassette stands 11-14.

FIG. 2 is a side view showing the configuration of the wafer edge polishing device 17. As shown in FIG. 2, the wafer edge polishing device 17 includes a wafer rotation mechanism 22, a wafer lifting mechanism 23, a roller group 24, a roller movement mechanism 25, and a tape transfer mechanism 26. Note that FIG. 2 shows the central axis direction in which the central axis of the wafer 27 extends as the Z direction. Also, in FIG. 2, the directions in which the roller group 24 described below moves toward and away from the wafer 27 and the direction in which the polishing tape moved by the roller group 24 approaches and separates from the edge surface of the wafer 27 are the same direction and perpendicular to the Z direction, and these directions are shown as the Y direction. Furthermore, FIG. 2 shows the direction perpendicular to the Y direction and the Z direction as the X direction, and the XY plane including the X direction and the Y direction is the surface direction of the wafer 27.

The wafer edge polishing device 17 is provided with a transfer table 30a, and the wafer 27 is loaded onto the transfer table 30a from the wafer edge inspection device 16 by the transfer machine 18 (Fig. 1). The wafer edge polishing device 17 is provided with a transfer holder 21 that is movable via an arm 20, and the arm 20 is moved to grip the wafer 27 loaded onto the transfer table 30a with the transfer holder 21. The wafer edge polishing device 17 then transports the transfer holder 21 holding the wafer 27 to the table 30 of the wafer rotation mechanism 22 by the arm 20, and loads the wafer 27 onto the table 30 in the optimal position and orientation.

The wafer rotation mechanism 22 has a table 30 attached to the upper end of a rotating shaft 29 that is rotated by a drive motor 28, and air is drawn in from the top of the table 30 by an air intake unit (not shown). As a result, when a wafer 27 is placed on the table 30, the wafer rotation mechanism 22 vacuum-adsorbs the wafer 27 to the table 30 and supports the wafer 27 with the table 30. By driving the drive motor 28, the wafer rotation mechanism 22 rotates the table 30 around the rotating shaft 29, and rotates the wafer 27 in a circumferential direction in a horizontal plane with the central axis of the wafer 27 as the axis of rotation while the wafer 27 is supported by the table 30.

The wafer lifting mechanism 23 holds the wafer rotation mechanism 22 and moves the wafer 27 in the central axis direction (Z direction) via the wafer rotation mechanism 22.

The roller group 24, roller movement mechanism 25, and tape transfer mechanism 26 are referred to as the polishing mechanism 31. The polishing mechanism 31 is provided on a base plate 32. The base plate 32 is configured to be freely movable in a direction toward or away from the edge face of the wafer 27 (Y direction), and moves the polishing mechanism 31 provided on the base plate 32 in a direction toward or away from the edge face of the wafer 27.

FIG. 3 is a side view of the main part showing the configuration of the polishing mechanism 31. The roller group 24 is arranged radially outside the wafer 27, and the polishing tape 33 is stretched and transported in the thickness direction of the wafer 27. The tape transport mechanism 26 transports the polishing tape 33 toward the roller group 24, applies tension to the polishing tape 33 to stretch it on the roller group 24, and transports the polishing tape 33 on the roller group 24 in a stretched state. The polishing tape 33 is, for example, a film coated with ultrafine abrasive particles uniformly dispersed in a resin adhesive, and polishes the end surface 27a to a set roughness according to the grain size of the abrasive. The dashed line O shown in FIG. 3 is a reference line indicating the reference in the height direction (Z direction) of the roller group 24.

In this case, the tape transfer mechanism 26 includes a tape feed reel 34, a tape take-up reel 35,

tension rollers

36, 37,

motor rollers

38, 39, and

pressure rollers

40, 41, and the tape feed reel 34, tape take-up reel 35,

tension rollers

36, 37,

motor rollers

38, 39, and

pressure rollers

40, 41 are mounted on a base plate 32. The tension roller 36, motor roller 38, and pressure roller 40 are disposed on the feed side that transports the polishing tape 33 from the tape feed reel 34 to the roller group 24. The tension roller 37, motor roller 39, and pressure roller 41 are disposed on the take-up side that transports the polishing tape 33 from the roller group 24 to the tape take-up reel 35.

The polishing tape 33 pulled out from the tape feed reel 34 is bent at the outer peripheral surface of the tension roller 36, guided between the motor roller 38 and the pressure roller 40, sandwiched between the motor roller 38 and the pressure roller 40, and then sent out from between the motor roller 38 and the pressure roller 40, bent at the outer peripheral surface of the motor roller 38 toward the roller group 24, and transported to the roller group 24. The polishing tape 33 transported to the roller group 24 is sent out from the roller group 24 toward the motor roller 39, guided along the outer peripheral surface of the motor roller 39 between the motor roller 39 and the pressure roller 41, sandwiched between the motor roller 39 and the pressure roller 41, sent out from between the motor roller 39 and the pressure roller 41 toward the tension roller 37, bent at the outer peripheral surface of the tension roller 37 toward the tape take-up reel 35, and taken up by the tape take-up reel 35.

In this way, the tape transfer mechanism 26 transfers the polishing tape 33 to the first roller 43 and the second roller 44 that constitute the roller group 24, and the polishing tape 33 wound around the first roller 43 and the second roller 44 is stretched between the first roller 43 and the second roller 44, and continues to transfer the polishing tape 33 between the first roller 43 and the second roller 44. That is, when polishing the end surface 27a of the wafer 27, the tape transfer mechanism 26 drives the

motor rollers

38, 39 to rotate the

motor rollers

38, 39, thereby guiding the polishing tape 33 sent out from the tape feed reel 34 along the above-mentioned transport path to the first roller 43, winding the polishing tape 33 around the outer periphery of the first roller 43, changing the transport direction of the polishing tape 33 and extending it toward the second roller 44, and winding the polishing tape 33 around the outer periphery of the second roller 44, changing the transport direction of the polishing tape 33, and continues to transport the polishing tape 33 toward the tape take-up reel 35.

The roller moving mechanism 25 is provided on the base plate 32, and moves together with the base plate 32 toward or away from the end surface 27a of the wafer 27 as the base plate 32 moves toward or away from the end surface 27a of the wafer 27 (Y direction). Here, FIG. 4 is a perspective view showing the configuration of the main parts of the roller moving mechanism 25. As shown in FIG. 4, the roller moving mechanism 25 is provided with a first roller 43 and a second roller 44 as the roller group 24, and is configured to move each of the first roller 43 and the second roller 44 independently toward or away from the end surface 27a of the wafer 27 (Y direction) separately from the movement in the Y direction by the base plate 32.

The first roller 43 and the second roller 44 are arranged facing each other at a predetermined distance in the thickness direction (Z direction) of the wafer 27 perpendicular to the rotation plane of the wafer 27 on the XY plane. The first roller 43 is arranged radially outward of the wafer 27 supported by the wafer rotation mechanism 22, and is arranged above the second roller 44. The first roller 43 is supported by the upper moving plate 45 via upper connecting

plates

45a and 45b. The upper moving plate 45 is provided so as to be movable in the Y direction (horizontal direction) relative to the base plate 32 (see FIG. 3). As the upper moving plate 45 moves in the Y direction, the first roller 43 moves in a direction approaching and away from the end surface 27a of the wafer 27 (Y direction) in conjunction with the movement of the upper moving plate 45.

The upper connecting

plates

45a, 45b on which the first roller 43 is provided are plate-shaped members with their longitudinal direction in the Y direction, and a rod-shaped cross section 45c is hung between the upper connecting

plates

45a, 45b, which are arranged opposite each other at a predetermined distance. The first roller 43 is hung between the upper connecting

plates

45a, 45b which are arranged opposite each other at a predetermined distance, and each end is rotatably provided at the tip side of the upper connecting

plates

45a, 45b.

The second roller 44 is disposed radially outward of the wafer 27 supported by the wafer rotation mechanism 22, and disposed below the first roller 43. The second roller 44 is supported by the lower moving plate 46 via lower connecting

plates

46a and 46b. The lower moving plate 46 is provided so as to be movable in the Y direction relative to the base plate 32. As the lower moving plate 46 moves in the Y direction, the second roller 44 moves in a direction toward and away from the end surface 27a of the wafer 27 (Y direction) in conjunction with the movement of the lower moving plate 46.

The lower connecting

plates

46a, 46b on which the second roller 44 is provided are plate-shaped members with their longitudinal direction in the Y direction, and a rod-shaped cross section 46c is hung between the lower connecting

plates

46a, 46b, which are arranged opposite each other at a predetermined distance by the cross section 46c. The second roller 44 is hung between the lower connecting

plates

46a, 46b which are arranged opposite each other at a predetermined distance, and each end is rotatably provided at the tip side of the lower connecting

plates

46a, 46b.

The upper moving plate 45 and the lower moving plate 46 are connected to the upper connecting plate 45a and the lower connecting plate 46a at their tip ends, respectively, and are connected to the rotating plate 47 via the annular part 49 at their base ends. The rotating plate 47 has a drive plate 48 and annular part 49 fixed to the rotation center 47a. The annular part 49 is formed in an elliptical shape with its longitudinal direction in the Z direction, and its center is fixed to the rotation center 47a of the rotating plate 47. The annular part 49 has an upper long hole 51 above the rotation center 47a, and a circular upper cam 52 provided at the base of the upper moving plate 45 is rotatably engaged with the upper long hole 51. The annular part 49 also has a lower long hole 53 below the rotation center 47a, and a circular lower cam 54 provided at the base of the lower moving plate 46 is rotatably engaged with the lower long hole 53.

The driving plate 48 has an arc-shaped plate portion 48a and a long plate portion 48b that extends linearly from the center of the inner diameter side of the arc-shaped plate portion 48a toward the radial direction, and has a configuration in which an upper step portion 48c and a lower step portion 48d are formed at the connecting point of the arc-shaped plate portion 48a and the long plate portion 48b. The driving plate 48 has the tip side of the long plate portion 48b fixed to the rotation center 47a of the rotating plate 47, the arc-shaped plate portion 48a is connected to the driving unit 50, and the driving force from the driving unit 50 is applied to the arc-shaped plate portion 48a. In addition, the driving plate 48 has an upper long hole 51 of the annular portion 49 arranged above the long plate portion 48b, and a lower long hole 53 of the annular portion 49 arranged below the long plate portion 48b, and the long plate portion 48b is arranged between the upper moving plate 45 and the lower moving plate 46.

The driving force from the drive unit 50 pushes the arc-shaped plate portion 48a upward around the rotation center 47a as the axis of rotation of the drive plate 48, causing the long plate portion 48b and the annular portion 49 to rotate counterclockwise around the rotation center 47a of the rotating plate 47. The driving force from the drive unit 50 pushes the arc-shaped plate portion 48a downward around the rotation center 47a as the axis of rotation of the drive plate 48, causing the long plate portion 48b and the annular portion 49 to rotate clockwise around the rotation center 47a of the rotating plate 47.

Here, the state in which the longitudinal direction of the long plate portion 48b of the drive plate 48 coincides with the reference line O that passes through the rotation center 47a and extends in the Y direction is taken as the reference position of the drive plate 48, and below, the configuration when the drive plate 48 is in the reference position will be described. When the drive plate 48 is in the reference position, the longitudinal direction of the annular portion 49 extends in the Z direction perpendicular to the Y direction, and the upper long hole 51 of the annular portion 49 is positioned above the rotation center 47a, while the lower long hole 53 of the annular portion 49 is positioned below the rotation center 47a. As a result, the upper cam 52 engaged with the upper long hole 51 of the annular portion 49 and the lower cam 54 engaged with the lower long hole 53 of the annular portion 49 are positioned in a straight line with the rotation center 47a in the Z direction.

When the driving plate 48 is in the reference position, as shown in FIG. 5, the first roller 43 and the second roller 44 are arranged in a straight line facing each other in the Z direction, and the distances in the Y direction to the edge surface 27a of the wafer 27 are the same. Also, when the driving plate 48 is in the reference position, the distance in the Z direction (thickness direction of the wafer 27) from the outer circumferential surface of the first roller 43 on which the polishing tape 33 is stretched to the outer circumferential surface of the second roller 44 is selected to be smaller than the thickness of the wafer 27. In other words, the entire edge surface of the wafer 27 cannot be placed in the gap between the first roller 43 and the second roller 44, which are moved with the polishing tape 33 stretched, and the first roller 43 and the second roller 44 cannot pinch the wafer 27 in the thickness direction.

Between the first roller 43 and the second roller 44, a back pad 55 is provided to support the polishing tape 33 transported between the first roller 43 and the second roller 44. The back pad 55 is made of metal or resin and has four faces with a roughly rectangular cross section, with the polishing tape 33 contacting the surface portion 55b of one of the four faces. In this case, the back pad 55 provided between the first roller 43 and the second roller 44 is positioned on a reference line O that indicates the reference in the height direction (Z direction) of the roller group 24.

When the first roller 43 and the second roller 44 move in a direction approaching the edge surface 27a of the wafer 27, the rear pad 55 presses the polishing tape 33 transported between the first roller 43 and the second roller 44 against the edge surface 27a of the wafer 27 with the surface portion 55b, applying a surface pressure to the edge surface 27a of the wafer 27. The rear pad 55 can use any of its four surfaces as the surface portion 55b. For example, after a predetermined period of time has elapsed, the rear pad 55 can be rotated approximately 90 degrees around the axis 55a of the rear pad 55, and a surface other than the surface that was in contact with the polishing tape 33 can be used as the surface portion 55b.

The first roller 43 and the second roller 44 are connected to elliptical

annular linking parts

56a, 56b having a long hole 57. The linking

parts

56a, 56b are arranged opposite each other in the X direction, and when the drive plate 48 is in the reference position, the longitudinal direction of the long hole 57 is arranged along the Z direction. The long holes 57 of the linking

parts

56a, 56b in this embodiment are selected to have a length slightly greater than the thickness of the wafer 27. The linking part 56a is positioned by inserting one end of the first roller 43, the second roller 44, and the back pad 55 into the long hole 57, and fitting the frame of the long hole 57 into grooves formed on the outer circumferential surfaces of one end of the first roller 43, the second roller 44, and the back pad 55. The linking portion 56b is positioned by inserting the other ends of the first roller 43, the second roller 44, and the back pad 55 into the long hole 57, and fitting the frame of the long hole 57 into the grooves formed on the outer circumferential surfaces of the other ends of the first roller 43, the second roller 44, and the back pad 55.

In the linking

parts

56a and 56b, the first roller 43, the second roller 44, and the back pad 55 are rotatably arranged within the long hole 57, the back pad 55 is positioned in the middle of the long hole 57, and the first roller 43 and the second roller 44 are arranged to be movable along the longitudinal direction within the long hole 57. When the first roller 43 and the second roller 44 independently move toward or away from the end surface 27a of the wafer 27 (Y direction), the linking

parts

56a and 56b guide the first roller 43 and the second roller 44 along the long hole 57, and the long hole 57 regulates the amount of movement of the first roller 43 and the second roller 44 in the Y direction.

The operation of the above configuration will be explained. As shown in FIG. 1, in the wafer processing system 10, the transfer machine 18 unloads one wafer 27 from one of the four cassette placement tables 11-14 and loads the wafer 27 into the wafer edge surface inspection device 16. The shape of the edge surface 27a of the wafer 27 loaded into the wafer edge surface inspection device 16 is inspected by the wafer edge surface inspection device 16. Data on the inspected edge surface shape is sent to the wafer edge surface polishing device 17. Then, after inspection by the wafer edge surface inspection device 16, the wafer 27 is unloaded from the wafer edge surface inspection device 16 by the transfer machine 18 and loaded into the wafer edge surface polishing device 17.

The wafer edge polishing device 17 acquires data on the shape of the edge 27a of the wafer 27 inspected by the wafer edge inspection device 16, and based on that data, determines the height position of the wafer 27 during polishing to form the edge 27a of the wafer 27 into an optimal shape, as well as the contact and separation state of the first roller 43 and the second roller 44. Here, the optimal shape of the edge 27a of the wafer 27 is, for example, an R-shape that finishes the edge 27a of the wafer 27 into an arc shape that is symmetrical in the thickness direction of the wafer 27. Note that the optimal shape of the edge 27a of the wafer 27 is not limited to an R-shape, and may be an asymmetric shape that is not symmetrical in the thickness direction.

The contact and separation state of the first roller 43 and the second roller 44 can be divided into at least three types: a first polishing operation, a second polishing operation, and a third polishing operation. In the first polishing operation, as shown in FIG. 5, the driving plate 48 is set to the reference position, and the first roller 43 and the second roller 44 are arranged in a straight line in the Z direction with the first roller 43 and the second roller 44 in close proximity to the back pad 55, and the polishing tape 33 is continuously transported while stretched along the Z direction. In the first polishing operation, the base plate 32 moves in this state in a direction approaching the end surface 27a of the wafer 27, thereby moving the first roller 43 and the second roller 44 together with the base plate 32 in a direction approaching the end surface 27a of the wafer 27. As a result, in the first polishing operation, the polishing tape 33 transported between the first roller 43 and the second roller 44 is pressed against the end surface 27a of the wafer 27, and the end surface 27a of the wafer 27 can be polished vertically along the Z direction.

6 and 7, in the second polishing operation, the upper sides of the linking

portions

56a, 56b are tilted toward the wafer 27 with the back pad 55 at the center. As a result, in the second polishing operation, the first roller 43 moves in a direction away from the back pad 55 along the long holes 57 of the linking

portions

56a, 56b, thereby moving the first roller 43 in a direction approaching the edge surface 27a of the wafer 27, and the second roller 44 moves in a direction away from the back pad 55 along the long holes 57 of the linking

portions

56a, 56b, thereby moving the second roller 44 in a direction away from the edge surface 27a of the wafer 27. In addition, the distance between the first roller 43 and the second roller 44 in the thickness direction of the wafer 27 during the second polishing operation is the same as the distance between the first roller 43 and the second roller 44 in the thickness direction of the wafer 27 during the first polishing operation, so the gap between the first roller 43 and the second roller 44 in the thickness direction of the wafer 27 can be kept narrow without widening.

As a result, in the second polishing operation, the polishing tape 33, which is continuously transported while stretched between the first roller 43 and the second roller 44, is inclined from top to bottom so as to gradually move away from the edge surface 27a of the wafer 27. In the second polishing operation, the base plate 32 moves in a direction approaching the edge surface 27a of the wafer 27 while remaining in this state, thereby moving the first roller 43 and the second roller 44 together with the base plate 32 in a direction approaching the edge surface 27a of the wafer 27. As a result, in the second polishing operation, the polishing tape 33, which is continuously transported while inclined between the first roller 43 and the second roller 44, can be pressed against the periphery of the upper corner of the edge surface 27a of the rotating wafer 27, thereby polishing the periphery of the upper corner of the edge surface 27a of the wafer 27.

8 and 9, in the third polishing operation, the lower sides of the linking

portions

56a, 56b are tilted toward the wafer 27 with the back pad 55 at the center. As a result, in the third polishing operation, the second roller 44 moves in a direction away from the back pad 55 along the long holes 57 of the linking

portions

56a, 56b, thereby moving the second roller 44 in a direction approaching the edge surface 27a of the wafer 27, and the first roller 43 moves in a direction away from the back pad 55 along the long holes 57 of the linking

portions

56a, 56b, thereby moving the first roller 43 in a direction away from the edge surface 27a of the wafer 27. In addition, the distance between the first roller 43 and the second roller 44 in the thickness direction of the wafer 27 during the third polishing operation is the same as the distance between the first roller 43 and the second roller 44 in the thickness direction of the wafer 27 during the first polishing operation, so the gap between the first roller 43 and the second roller 44 in the thickness direction of the wafer 27 can be kept narrow without widening.

As a result, in the third polishing operation, the polishing tape 33, which is continuously transported while stretched between the first roller 43 and the second roller 44, is inclined from the bottom to the top so as to gradually move away from the edge surface 27a of the wafer 27. In the third polishing operation, the base plate 32 moves in a direction approaching the edge surface 27a of the wafer 27 while remaining in this state, thereby moving the first roller 43 and the second roller 44 together with the base plate 32 in a direction approaching the edge surface 27a of the wafer 27. As a result, in the third polishing operation, the polishing tape 33, which is continuously transported while inclined between the first roller 43 and the second roller 44, can be pressed against the periphery of the lower corner of the edge surface 27a of the wafer 27, and the periphery of the lower corner of the edge surface 27a of the wafer 27 can be polished.

In addition to this configuration, when performing the first polishing operation, the second polishing operation, and the third polishing operation, the wafer edge polishing device 17 is configured to appropriately move the wafer 27 in the central axis direction (Z direction) via the wafer rotation mechanism 22 by the wafer lifting mechanism 23, thereby making it possible to adjust the position where the edge surface 27a of the wafer 27 rubs against the polishing tape 33.

The order of the polishing operations is determined according to the shape of the end surface 27a of the wafer 27. The order of the polishing operations may be, for example, the first polishing operation, the second polishing operation, and the third polishing operation. The order of the polishing operations is not limited to the above-mentioned order, and for example, the second polishing operation and the third polishing operation may be reversed. When performing such a first polishing operation, second polishing operation, and/or third polishing operation, the wafer 27 is rotated appropriately in the circumferential direction by the wafer rotation mechanism 22, and the polishing tape 33 transported between the first roller 43 and the second roller 44 polishes the end surface 27a of the wafer 27 with the polishing tape 33 while changing the circumferential position at which the polishing tape 33 slides against the end surface 27a of the wafer 27.

In the wafer edge polishing device 17, based on the inspection results of the shape of the edge 27a of the wafer 27 obtained by the wafer edge inspection device 16, not only the inclination angle of the polishing tape 33 for each wafer 27 but also the height position of the wafer 27 is determined, and the first polishing operation, the second polishing operation, and/or the third polishing operation described above is started.

For example, in the first polishing operation, as shown in FIG. 5, the wafer 27 is moved in the central axis direction (Z direction) by the wafer lifting mechanism 23 so that the intermediate position 27b of the thickness of the wafer 27 is at the same height as the reference line O passing through the back pad 55 provided at the intermediate position between the first roller 43 and the second roller 44. Then, in the first polishing operation, the drive plate 48 is set to the reference position and the first roller 43 and the second roller 44 are arranged in a straight line in the Z direction, and the base plate 32 is moved in a direction approaching the end surface 27a of the wafer 27. As a result, in the first polishing operation, the polishing tape 33 being transferred perpendicularly to the first roller 43 and the second roller 44 is pressed against the end surface 27a of the wafer 27 supported by the wafer rotating mechanism 22, and the end surface 27a of the wafer 27 can be polished so that its shape is a vertical surface along the Z direction.

In the second polishing operation, as shown in FIG. 7, the wafer 27 is lowered in the central axis direction (Z direction) by the wafer lifting mechanism 23 so that the intermediate position 27b of the thickness of the wafer 27 is at a height position below the reference line O passing through the back pad 55. Then, in the second polishing operation, as shown in FIG. 6, the drive plate 48 is rotated counterclockwise to rotate the rotating plate 47 and the annular portion 49 counterclockwise. The upper cam 52 of the upper moving plate 45 provided in the upper long hole 51 of the annular portion 49 is pushed in a direction approaching the end surface 27a of the wafer 27 in conjunction with the annular portion 49 rotating counterclockwise. As a result, the first roller 43 provided on the tip side of the upper moving plate 45 moves in a direction approaching the end surface 27a of the wafer 27 in conjunction with the upper moving plate 45. On the other hand, when the annular portion 49 of the lower moving plate 46 rotates counterclockwise, the lower cam 54 provided in the lower long hole 53 of the annular portion 49 is pulled in a direction away from the end surface 27a of the wafer 27 in conjunction with the annular portion 49 rotating counterclockwise. The second roller 44 provided on the tip side of the lower moving plate 46 moves in a direction away from the end surface 27a of the wafer 27 in conjunction with the lower moving plate 46.

As a result, as shown in FIG. 7, the polishing tape 33, which is stretched between the first roller 43 and the second roller 44 and continuously transported, is inclined so that the upper side approaches the edge surface 27a of the wafer 27 and the lower side moves away from it. At this time, the back pad 55, which is fixed to the center of rotation of the linking

parts

56a, 56b that have rotated counterclockwise, rotates counterclockwise around the axis 55a together with the linking

parts

56a, 56b in accordance with the inclination of the polishing tape 33, and maintains a state in which the surface part 55b is pressed against the surface of the polishing tape 33. As a result, the back pad 55 receives the load applied to the polishing tape 33 from the edge surface 27a of the wafer 27 when the polishing tape 33 is pressed against the edge surface 27a of the wafer 27.

In the second polishing operation, the intermediate position 27b of the thickness of the wafer 27 is set at a height position below the reference line O passing through the back pad 55, and the polishing tape 33, which is continuously transported between the first roller 43 and the second roller 44, is tilted so that the upper side approaches the end surface 27a of the wafer 27 and the lower side moves away from it, and the base plate 32 is moved in a direction approaching the end surface 27a of the wafer 27. As a result, in the second polishing operation, the polishing tape 33, which is continuously transported while tilted between the first roller 43 and the second roller 44, can be pressed against the upper corner of the end surface 27a of the wafer 27 supported by the wafer rotation mechanism 22, and the shape of the upper corner of the end surface of the wafer 27 can be polished to a curved R shape.

In the third polishing operation, as shown in FIG. 9, the wafer 27 is raised in the central axis direction (Z direction) by the wafer lifting mechanism 23 so that the intermediate position 27b of the thickness of the wafer 27 is at a height position above the reference line O passing through the back pad 55. Then, in the third polishing operation, as shown in FIG. 8, the drive plate 48 is rotated clockwise to rotate the rotating plate 47 and the annular portion 49 clockwise. The upper moving plate 45 moves in a direction away from the end surface 27a of the wafer 27 in conjunction with the annular portion 49 rotating clockwise, with the upper cam 52 provided in the upper long hole 51 of the annular portion 49. On the other hand, when the annular portion 49 rotates clockwise, the lower moving plate 46 moves in a direction approaching the end surface 27a of the wafer 27 in conjunction with the annular portion 49 rotating clockwise, with the lower cam 54 provided in the lower long hole 53 of the annular portion 49. The second roller 44, which is provided at the tip side of the lower moving plate 46, moves in conjunction with the lower moving plate 46 in a direction approaching the edge surface 27a of the wafer 27.

As a result, as shown in FIG. 9, the polishing tape 33, which is stretched between the first roller 43 and the second roller 44 and continuously transported, is inclined so that the lower side approaches the edge surface 27a of the wafer 27 and the upper side moves away from it. At this time, the back pad 55, which is fixed to the center of rotation of the linking

parts

56a, 56b that rotate clockwise, rotates around the axis 55a together with the linking

parts

In the third polishing operation, the intermediate position 27b of the thickness of the wafer 27 is set at a height position above the reference line O passing through the back pad 55, and the polishing tape 33 being continuously transported between the first roller 43 and the second roller 44 is tilted so that the lower side approaches the end face 27a of the wafer 27 and the upper side moves away from it, and the base plate 32 is moved in a direction approaching the end face 27a of the wafer 27. As a result, in the third polishing operation, the polishing tape 33 being continuously transported in an inclined state between the first roller 43 and the second roller 44 can be pressed against the lower corner of the end face 27a of the wafer 27 supported by the wafer rotation mechanism 22, and the shape of the lower corner of the end face of the wafer 27 can be polished to a curved R shape.

In the above configuration, the wafer edge polishing device 17 supports the wafer 27 with the wafer rotation mechanism 22, and uses the roller movement mechanism 25 to move both or either of the first roller 43 and the second roller 44 in a direction approaching the edge surface 27a of the wafer 27 supported by the wafer rotation mechanism 22, and polishes the edge surface 27a of the wafer 27 with the polishing tape 33 that is continuously transported between the first roller 43 and the second roller 44. At this time, the wafer edge polishing device 17 uses the wafer lifting mechanism 23 to raise and lower the wafer 27 supported by the wafer rotation mechanism 22 in the central axis direction, thereby changing the position of the edge surface 27a of the wafer 27 that contacts the polishing tape 33 in the thickness direction of the wafer 27.

In this way, in the wafer edge polishing apparatus 17, the first roller 43 and the second roller 44 each move independently in a direction approaching the edge face 27a of the wafer 27, thereby changing the inclination angle of the polishing tape 33. In addition, the wafer 27 can be moved in the central axis direction by the wafer lifting mechanism 23. Therefore, by adjusting the inclination angle of the polishing tape 33, the position at which the polishing tape 33 contacts the edge face 27a of the wafer 27 can be changed, and the position at which the polishing tape 33 contacts the edge face 27a of the wafer 27 can also be changed by changing the height position of the edge face 27a of the wafer 27 along the central axis direction. Therefore, even if the entire end surface of the wafer 27 is not necessarily positioned between the first roller 43 and the second roller 44 on which the polishing tape 33 is transported, the entire end surface of the wafer 27 can be polished by appropriately changing the height position of the end surface 27a of the wafer 27. Therefore, even if the gap between the first roller 43 and the second roller 44 in the thickness direction of the wafer 27 is made smaller than before, the end surface 27a of the wafer 27 can be formed into an appropriate shape.

In the above embodiment, the first polishing operation is performed by moving the wafer 27 in the central axis direction (Z direction) using the wafer lifting mechanism 23 so that the intermediate position 27b of the thickness of the wafer 27 is at the same height as the reference line O passing through the back pad 55 provided at the intermediate position between the first roller 43 and the second roller 44, and the end surface 27a of the wafer 27 is polished with the polishing tape 33 stretched in the thickness direction of the wafer 27. However, the present invention is not limited to this. For example, the first polishing operation may be performed by using the wafer lifting mechanism 23 to move the intermediate position 27b of the thickness of the wafer 27 to a height position below the reference line O passing through the back pad 55 as shown in FIG. 7, or to move the intermediate position 27b of the thickness of the wafer 27 to a height position above the reference line O passing through the back pad 55 as shown in FIG. 9 (FIG. 9), and the end surface 27a of the wafer 27 may be polished with the polishing tape 33 stretched in the thickness direction of the wafer 27.

In addition, in the above-mentioned embodiment, the first polishing operation, the second polishing operation, and the third polishing operation are clearly separated and described, but the present invention is not limited to this. For example, while the polishing tape 33 is kept in sliding contact with the end surface 27a of the wafer 27, the height position of the wafer 27 and the inclination angle of the polishing tape 33 may be continuously changed so as to gradually switch between each state, such as from the first polishing operation state to the second polishing operation state, from the second polishing operation state to the first polishing operation state, from the first polishing operation state to the third polishing operation state, and from the third polishing operation state to the first polishing operation state, while keeping the polishing tape 33 in sliding contact with the end surface 27a of the wafer 27.

Furthermore, the back pad 55 is not limited to one having a rectangular cross section, and for example, a plate-shaped back pad 58 may be used as shown in FIG. 10. As shown in FIG. 10, a plate-shaped back pad 58 is provided between the first roller 43 and the second roller 44. The roller movement mechanism 25 shown in FIG. 10 includes a pair of the first roller 43 and the second roller 44, a pair of the first roller 43a and the second roller 44a, and

annular portions

59, 59a.

The annular portion 59 is an elliptical ring having a longitudinal direction, and the first roller 43 and the second roller 44 are provided at both ends in the longitudinal direction. The annular portion 59 has a rotation axis 60 at its longitudinal center, and is supported by the base plate 32 (FIG. 3) so as to be rotatable clockwise or counterclockwise around the rotation axis 60 in the YZ plane including the Y and Z directions. The annular portion 59a is also an elliptical ring having a longitudinal direction, like the annular portion 59, and the first roller 43a and the second roller 44a are provided at both ends in the longitudinal direction. The annular portion 59a has a rotation axis 60a at its longitudinal center, and is supported by the base plate 32 (FIG. 3) so as to be rotatable clockwise or counterclockwise around the rotation axis 60a in the YZ plane including the Y and Z directions.

The

annular parts

59, 59a are rotated counterclockwise or clockwise around the

rotation shafts

60, 60a by a drive unit (not shown), which moves the

first rollers

43, 43a and the

second rollers

44, 44a independently toward or away from the end face 27a of the wafer 27. Specifically, when the

annular parts

59, 59a rotate counterclockwise around the

rotation shafts

60, 60a, the

first rollers

43, 43a move toward the end face 27a of the wafer 27, and the

second rollers

44, 44a move away from the end face 27a of the wafer 27. When the

annular parts

59, 59a rotate clockwise around the

rotation shafts

60, 60a, the

first rollers

43, 43a move away from the end face 27a of the wafer 27, and the

second rollers

44, 44a move toward the end face 27a of the wafer 27. As a result, in the same manner as in the above-described embodiment, the polishing tape 33, which is stretched between the first roller 43 and the second roller 44 and is continuously transported, can be arranged vertically along the Z direction or tilted at a predetermined tilt angle. At this time, the back pad 58 tilts in the same manner in conjunction with the tilt of the annular portion 59, and supports the polishing tape 33 behind the polishing tape 33.

In the above-described embodiment, the wafer edge polishing device 17 is described as using one type of polishing tape 33 to polish the edge surface 27a of the wafer 27, but the present invention is not limited to this. For example, a wafer edge polishing device 62 may be applied that polishes the edge surface 27a of the wafer 27 by appropriately switching between multiple types of polishing tapes with different roughness, such as two or three types with different roughness.

As shown in FIG. 11, the wafer edge polishing device 62 is equipped with a tape switching mechanism 65 that switches between two types of polishing tape with different roughness: a first polishing tape 63 and a second polishing tape 64. The first polishing tape 63 has a predetermined grain size of abrasive, and the second polishing tape 64 has a different grain size of abrasive from that of the first polishing tape 63, for example, using an abrasive with a finer grain size than that of the first polishing tape 63.

In addition to the tape switching mechanism 65, the wafer edge polishing device 62 also includes a first roller group 66, a second roller group 67 arranged next to the first roller group 66, a first tape transfer mechanism 68, and a second tape transfer mechanism 69. Although not shown in FIG. 11, the device also includes a wafer rotation mechanism 22, a wafer lifting mechanism 23, and a roller movement mechanism 25, as in the above-mentioned embodiment.

The first roller group 66 has a first roller 66a and a second roller 66b arranged opposite each other in the thickness direction (Z direction) of the wafer 27, and the first polishing tape 63 transferred from the first tape transfer mechanism 68 is continuously transferred in a state in which it is stretched between the first roller 66a and the second roller 66b. The second roller group 67 has a third roller 67a and a fourth roller 67b arranged opposite each other in the thickness direction (Z direction) of the wafer 27, and the second polishing tape 64 transferred from the second tape transfer mechanism 69 is continuously transferred in a state in which it is stretched between the third roller 67a and the fourth roller 67b. In this embodiment, the first polishing tape 63 and the second polishing tape 64 are arranged side by side in the direction of the rotation axis of the first roller 66a, the second roller 66b, the third roller 67a, and the fourth roller 67b.

The tape switching mechanism 65 is configured to be able to move the base plate 32 (FIG. 3), on which the first roller group 66 and first tape transport mechanism 68, and the second roller group 67 and second tape transport mechanism 69 are provided, in the tangential direction (X direction) of the end surface 27a of the wafer 27 on the XY plane. The tape switching mechanism 65 positions either the first roller group 66 or the second roller group 67 to face the end surface 27a of the wafer 27 by relatively moving the base plate 32 in the tangential direction (X direction) of the end surface 27a of the wafer 27, and switches the polishing tape that is in sliding contact with the end surface 27a of the wafer 27 to either the first polishing tape 63 or the second polishing tape 64.

The operation of the first roller group 66 and the second roller group 67 when polishing the end surface 27a of the wafer 27, the adjustment of the inclination angle of the first polishing tape 63 and the second polishing tape 64, and the lifting and lowering operation of the wafer 27 by the wafer lifting mechanism 23 during the polishing operation are the same as those in the above-mentioned embodiment, so a description thereof will be omitted here. In addition, the tape switching mechanism 65 may be configured to move the wafer 27 rotated by the wafer rotation mechanism 22 in the tangential direction without moving the base plate 32.

This invention is not limited to the embodiments described above, and many modifications are possible within the technical concept of this invention by a person of ordinary skill in the art. For example, the roller movement mechanism 25 is not limited to the configuration described in FIG. 3, but may have a well-known configuration. Furthermore, the

back pads

55, 58 are not limited to being made of metal or resin, but may be made of well-known materials such as carbon, non-ferrous metals, and wood.

Furthermore, in the case of the plate-shaped back pad 58 described in FIG. 10, a heat sink, heat dissipation fins, heat dissipation sheet, or other heat dissipation member for dissipating heat may be provided on the back surface opposite the pad side that contacts the polishing tape 33. The heat sink has multiple fins and absorbs heat and dissipates it into the air. It is preferable to use copper or aluminum as the heat sink because of their good thermal conductivity.

In the above embodiment, the first roller 43a and the second roller 44a are moved toward and away from the end surface 27a of the wafer 27 simply by moving the base plate 32 toward or away from the end surface 27a of the wafer 27 (Y direction). However, the present invention is not limited to this. For example, as shown in FIG. 12, the base plate 32 having a load sensor 76 such as a load sensor may be attached to the base plate support portion 32a via a linear guide (not shown), and the base plate support portion 32a and the base plate 32 may be moved toward or away from the end surface 27a of the wafer 27 (Y direction) to move the first roller 43a and the second roller 44a toward and away from the end surface 27a of the wafer 27.

In this case, as shown in FIG. 12, between the upper moving plate 45 and the lower moving plate 46, there is a long plate-like or long rod-like sensor support part 75 running in parallel in the longitudinal direction of the upper moving plate 45 and the lower moving plate 46. At the tip of the sensor support part 75, elliptical ring-shaped linking

parts

56a, 56b having long holes 57 arranged opposite to each other in the X direction are provided, and the tip of the sensor support part 75 is rotatably provided at the center of the linking

parts

56a, 56b. The load sensor 76 detects the load acting on the polishing tape 33 from the wafer 27 when the polishing tape 33 stretched between the first roller 43a and the second roller 44a is brought into contact with the end surface 27a of the wafer 27. The linear guide provided on the base plate 32 can move the base plate 32 in the direction Y2 away from the wafer 27 based on the detection result of the load sensor 76, and adjust the contact force of the polishing tape 33 against the wafer 27.

12 is different from the configuration of the above-mentioned embodiment, in that a first link roller 71 is provided at the tip of the upper moving plate 45, and a second link roller 72 is provided at the tip of the lower moving plate 46, and the first link roller 71 and the second link roller 72 are hung between the long holes 57 of the

link parts

56a and 56b arranged opposite to each other in the X direction. Between the long holes 57 of the

link parts

56a and 56b, a first roller 43a is hung at the upper end and a second roller 44a is hung at the lower end. The polishing tape 33 is hung between the first roller 43a and the second roller 44a rotatably provided at the ends of the

link parts

56a and 56b, and the polishing tape 33 is supported by a back pad 55 provided between the first roller 43a and the second roller 44a.

Thus, in this embodiment, the first roller 43a and the second roller 44a are not provided on the upper moving plate 45 and the lower moving plate 46, but by moving the upper moving plate 45 and the lower moving plate 46 in a direction toward or away from the edge surface 27a of the wafer 27, as in the above-mentioned embodiment, the first roller 43a and the second roller 44a can be moved independently in a direction toward or away from the edge surface 27a of the wafer 27. This allows the polishing tape 33, which is stretched between the first roller 43a and the second roller 44a and is continuously transported, to be tilted, etc.

In the above configuration, in the wafer edge polishing device according to another embodiment, the base plate support portion 32a and the base plate 32 provided on the base plate support portion 32a via a linear guide are moved in a direction Y1 approaching the edge surface 27a of the wafer 27. As a result, the wafer edge polishing device brings the polishing tape 33, which is continuously transported by the first roller 43a and the second roller 44a, into contact with the edge surface 27a of the wafer 27 supported by the wafer rotation mechanism 22. At this time, when the polishing tape 33, which is continuously transported while being stretched between the first roller 43a and the second roller 44a, is brought into contact with the edge surface 27a of the wafer 27, the wafer edge polishing device can detect the load that the polishing tape 33 receives from the wafer 27 by the load sensor 76.

The wafer edge polishing device moves the base plate 32 in the direction Y2 away from the wafer 27 by driving the linear guide based on the load detected by the load sensor 76, and can adjust the contact force of the polishing tape 33 on the edge surface 27a of the wafer 27. This prevents the polishing tape 33 from being pressed too hard against the edge surface 27a of the wafer 27, and allows the polishing tape 33 to be pressed against the edge surface 27a of the wafer 27 with an optimal contact force, polishing the edge surface 27a more accurately.

In the above-mentioned embodiment, as shown in Figures 3 and 4, a configuration has been described in which a roller moving mechanism 25 is provided that includes an upper moving plate 45 as a first moving plate, a lower moving plate 46 as a second moving plate, a driving plate 48, and a driving unit 50 that applies a driving force to the driving plate 48. In this case, the roller moving mechanism 25 has the driving plate 48 pushing the arc-shaped plate portion 48a upward or downward with the rotation center 47a as the rotation axis by the driving force from the driving unit 50. As a result, the roller moving mechanism 25 moves the upper moving plate 45 and the lower moving plate 46 closer to or farther away from the end surface 27a of the wafer 27. However, the present invention is not limited to this. As another embodiment of the roller movement mechanism, for example, as shown in FIG. 13, a roller movement mechanism 251 may be provided that includes an upper moving plate 81 as a first moving plate, a lower moving plate 82 as a second moving plate, a pair of

engagement parts

81a, 82a, an engagement rotation part 83a, and a drive part 83.

As shown in FIG. 13, the upper moving plate 81, which is the first moving plate, and the lower moving plate 82, which is the second moving plate, are arranged symmetrically with respect to the reference line O of the wafer edge polishing device 80. The upper moving plate 81 is composed of a metal plate-shaped body having a longitudinal direction in the Y direction. The upper moving plate 81 has a first roller 43 rotatably attached to its tip. The upper moving plate 81 is attached to the base plate 32 so as to be movable in the direction (Y direction) in which the first roller 43 approaches or moves away from the edge surface 27a of the wafer 27. The upper moving plate 81 has a recess 811 formed on the surface facing the lower moving plate 82 in the center. An engagement portion 81a such as a rack is provided approximately in the center of the recess 811. The engagement portion 81a may be a worm or the like other than a rack.

The lower moving plate 82, like the upper moving plate 81, is made of a metal plate-shaped body having a longitudinal direction in the Y direction. The lower moving plate 82 has a second roller 44 rotatably attached to its tip. The lower moving plate 82 is arranged so that its longitudinal direction faces the longitudinal direction (Y-axis direction) of the upper moving plate 81, and is attached to the base plate 32 so as to be movable in the direction (Y direction) that moves the second roller 44 closer to or farther away from the end surface 27a of the wafer 27. The lower moving plate 82 has a recess 821 formed on the surface facing the upper moving plate 81. An engaging portion 82a such as a rack is provided approximately in the center of the recess 821. Note that the engaging portion 82a may be a worm or the like other than a rack, like the one engaging portion 81a.

The engaging rotation part 83a is provided between the recess 811 of the upper moving plate 81 and the recess 821 of the lower moving plate 82. The engaging rotation part 83a is provided so as to be rotatable around the center of rotation as the rotation axis by the driving force from the driving part 83 such as a motor. The engaging rotation part 83a is, for example, a pinion gear, and has a configuration in which irregularities are formed on the outer circumferential surface. The engaging rotation part 83a meshes with a pair of engaging

parts

81a, 82a of the upper moving plate 81 and the lower moving plate 82, respectively. The engaging rotation part 83a rotates counterclockwise and clockwise by the driving force from the driving part 83, and the engagement position with the pair of engaging

parts

81a, 82a moves as a result of the rotation. The engaging rotation part 83a moves the upper moving plate 81 and the lower moving plate 82 along the Y direction as it rotates. When the engaging rotation part 83a rotates counterclockwise, the upper moving plate 81 moves in a direction approaching the end surface 27a of the wafer 27, and at the same time, the lower moving plate 82 moves in a direction away from the end surface 27a of the wafer 27. Conversely, when the engaging rotation part 83a rotates clockwise, the upper moving plate 81 moves in a direction away from the end surface 27a of the wafer 27, and at the same time, the lower moving plate 82 moves in a direction approaching the end surface 27a of the wafer 27.

The upper moving plate 81 and the lower moving plate 82 are provided with a load sensor 84 at the base (rear end) side away from the end surface 27a of the wafer 27. The load sensor 84 may be, for example, a resistance strain gauge type load sensor. The load sensor 84 has an upper detection unit 84a and a lower detection unit 84b. The upper detection unit 84a abuts against the rear end of the upper moving plate 81 and detects the force acting in the Y direction of the upper moving plate 81 as the upper moving plate 81 moves. The lower detection unit 84b abuts against the rear end of the lower moving plate 82 and detects the force acting in the Y direction of the lower moving plate 82 as the lower moving plate 82 moves.

The tip of the upper moving plate 81 is provided with a first roller 43 constituting the roller group 24. The tip of the lower moving plate 82 is provided with a second roller 44 constituting the roller group 24. A back pad 55 is provided between the first roller 43 and the second roller 44. The polishing tape 33 to be transported is provided on the first roller 43, the second roller 44, and the surface of the back pad 55 facing the end face 27a of the wafer 27. The first roller 43, the second roller 44, and the back pad 55 are supported so as to be freely slidable by linking

parts

56a, 56b in which a long hole 57 is formed. The first roller 43, the second roller 44, and the back pad 55 move in a direction approaching the end face 27a of the wafer 27 or in a direction away from the end face 27a depending on the inclination state of the linking

parts

56a, 56b. The first roller 43, the second roller 44, the back pad 55, and the linking

parts

56a and 56b have the same configuration as those shown in Figures 4 and 5, and detailed description will be omitted.

The contact/separation states of the first roller 43 and the second roller 44 can be divided into at least three types, the first polishing operation, the second polishing operation, and the third polishing operation, as in the above-mentioned embodiment. In the first polishing operation, as shown in FIG. 13, the protruding positions of the first roller 43, the second roller 44, and the back pad 55 relative to the edge surface 27a of the wafer 27 are aligned in the Z direction, and the polishing tape 33 is moved in a stretched state along the Z direction. At this time, the Z direction position of the middle position 27b of the thickness of the wafer 27 and the reference line O of the wafer edge polishing device 80 are aligned by a wafer lifting mechanism (not shown).

Next, the roller moving mechanism 251 brings the polishing tape 33 stretched between the first roller 43 and the second roller 44 into contact with the end surface 27a of the wafer 27, and vertically polishes the end surface 27a of the wafer 27 along the Z direction. The load sensor 84 detects the force in the Y direction acting on the upper moving plate 81 by the upper detection unit 84a, and detects the force in the Y direction acting on the lower moving plate 82 by the lower detection unit 84b. The roller moving mechanism 251 rotates the engaging rotation unit 83a according to the force detected by the load sensor 84, and changes the meshing position between the engaging rotation unit 83a and one of the engaging units 81a and the meshing position between the engaging rotation unit 83a and the other engaging unit 82a. As a result, the roller moving mechanism 251 adjusts the state of contact of the polishing tape 33 with the end surface 27a of the wafer 27 so that the amount of polishing of the end surface 27a of the wafer 27 is uniform.

In the second polishing operation, as shown in FIG. 14, the drive unit 83 rotates the engagement rotation unit 83a counterclockwise, moving the meshing position between the engagement rotation unit 83a and one of the engagement units 81a toward the rear end of the engagement unit 81a, and simultaneously moving the meshing position between the engagement rotation unit 83a and the other engagement unit 82a toward the tip end of the engagement unit 82a. The upper moving plate 81 moves toward the edge surface 27a of the wafer 27, and the lower moving plate 82 moves away from the edge surface 27a of the wafer 27. At this time, the intermediate position 27b of the thickness of the wafer 27 is moved downward in the Z direction below the reference line O of the wafer edge polishing device 80 by a wafer lifting mechanism (not shown).

In the second polishing operation, the upper sides of the linking

parts

56a, 56b are tilted toward the wafer 27 around the back pad 55. As a result, in the second polishing operation, the first roller 43 is moved along the long holes 57 of the linking

parts

56a, 56b in a direction approaching the wafer 27 around the back pad 55, and at the same time, the second roller 44 is moved in a direction away from the wafer 27 around the back pad 55. Due to the tilted state of the first roller 43, second roller 44, and back pad 55, the polishing tape 33 is tilted so that it gradually moves away from the edge surface 27a of the wafer 27 from the top to the bottom in the Z direction.

Therefore, in the second polishing operation, the polishing tape 33, which is continuously transferred in an inclined state between the first roller 43 and the second roller 44, is pressed against the upper corners of the end surface 27a of the rotating wafer 27, and the upper corners of the end surface 27a of the wafer 27 can be polished by the polishing tape 33. As in the first polishing operation, in the second polishing operation, the roller moving mechanism 251 detects the forces acting on the upper moving plate 81 and the lower moving plate 82 by the upper detection portion 84a and the lower detection portion 84b of the load sensor 84, and adjusts the meshing positions of the engaging rotation portion 83a and the pair of engaging

portions

81a, 82a based on the detection results. As a result, the roller moving mechanism 251 changes the contact state of the polishing tape 33 against the end surface 27a of the wafer 27, and adjusts the amount of polishing around the upper end surface of the end surface 27a of the wafer 27.

In the third polishing operation, as shown in FIG. 15, the drive unit 83 rotates the engagement rotation unit 83a clockwise, moving the meshing position between the engagement rotation unit 83a and one of the engagement units 81a toward the tip end of the engagement unit 81a, and simultaneously moving the meshing position between the engagement rotation unit 83a and the other engagement unit 82a toward the rear end of the engagement unit 82a. The upper moving plate 81 moves in a direction away from the edge surface 27a of the wafer 27, and the lower moving plate 82 moves in a direction approaching the edge surface 27a of the wafer 27. At this time, the wafer lifting mechanism (not shown) moves the intermediate position 27b of the thickness of the wafer 27 upward in the Z direction above the reference line O of the wafer edge polishing device 80.

In the third polishing operation, the lower sides of the linking

parts

56a, 56b are tilted toward the wafer 27 around the back pad 55. As a result, in the third polishing operation, the first roller 43 is moved along the long holes 57 of the linking

parts

56a, 56b in a direction away from the wafer 27 around the back pad 55, and at the same time, the second roller 44 is moved in a direction approaching the wafer 27 around the back pad 55. Due to the tilted state of the first roller 43, second roller 44, and back pad 55, the polishing tape 33 is tilted from the top to the bottom in the Z direction so as to gradually approach the edge surface 27a of the wafer 27.

Therefore, in the third polishing operation, the polishing tape 33, which is continuously transferred in an inclined state between the first roller 43 and the second roller 44, is pressed against the lower corners of the end face 27a of the rotating wafer 27, and the lower corners of the end face 27a of the wafer 27 can be polished by the polishing tape 33. As in the first polishing operation, in the third polishing operation, the roller moving mechanism 251 detects the compressive force acting on the upper moving plate 81 and the lower moving plate 82 by the upper detection part 84a and the lower detection part 84b of the load sensor 84, and adjusts the meshing positions of the engaging rotation part 83a and the pair of engaging

parts

81a, 82a based on the detection results. As a result, the roller moving mechanism 251 changes the contact state of the polishing tape 33 against the end face 27a of the wafer 27, and adjusts the amount of polishing around the lower end face of the end face 27a of the wafer 27.

This embodiment also provides the same effects and advantages as the above-mentioned embodiment. Furthermore, this embodiment allows the upper moving plate 81 and the lower moving plate 82 to be moved closer to or farther away from the edge surface 27a of the wafer 27 with a simple structure using an engaging rotating part and an engaging part, such as a rack and pinion. This allows for a simplified structure of the wafer edge surface polishing device 80, and is expected to improve durability due to the simple structure.

Also, the wafer edge polishing device 80 equipped with the roller moving mechanism 251 may be configured to have a tape switching mechanism 65 for switching between the first polishing tape 63 and the second polishing tape 64 of two different roughnesses, as shown in FIG. 11. In this case, like the wafer edge polishing device 62 described above, the wafer edge polishing device 80 is equipped with a first roller group 66, a second roller group 67 provided next to the first roller group 66, a first tape transfer mechanism 68, and a second tape transfer mechanism 69 in addition to the tape switching mechanism 65. The wafer edge polishing device 80 can adjust the inclination angle of the first polishing tape 63 and the second polishing tape 64 by rotating the engagement rotation part 83a by the drive part 83 to adjust the meshing positions of the engagement rotation part 83a and the pair of

engagement parts

81a, 82a. This allows the contact state of the first polishing tape 63 and the second polishing tape 64 with the edge surface 27a of the wafer 27 to be changed. In addition, the switching operation of the first polishing tape 63 or the second polishing tape 64 by the tape switching mechanism 65, the operation of the first roller group 66 and the second roller group 67 when polishing the end surface 27a of the wafer 27, the adjustment operation of the inclination angle of the first polishing tape 63 and the second polishing tape 64, the lifting and lowering operation of the wafer 27 by the wafer lifting mechanism 23 during the polishing operation, etc. are the same as those in the above-mentioned embodiment, so their explanations will be omitted here.

16 Wafer

edge inspection device

17, 62, 80 Wafer edge polishing device 22 Wafer rotation mechanism 23

Wafer lifting mechanism

25, 251 Roller movement mechanism 26 Tape transfer mechanism 27 Wafer 27a Edge 29 Rotating

shaft

43,

43a First roller

44, 44a Second roller 63 First polishing tape 64 Second polishing tape 65 Tape switching mechanism 68 First tape transfer mechanism 69 Second tape transfer mechanism 81 Upper moving plate (first moving plate)
82 Lower moving plate (second moving plate)
81a, 82a Engagement portion 83 Drive portion 83a Engagement rotation portion

Claims

a wafer rotation mechanism that supports the wafer and rotates the wafer in a circumferential direction around a central axis of the wafer;
a wafer lift mechanism that lifts and lowers the wafer supported by the wafer rotation mechanism in a central axis direction;
a first roller disposed radially outward of the wafer supported by the wafer rotation mechanism;
a second roller disposed radially outward of the wafer supported by the wafer rotation mechanism and opposed to the first roller in a thickness direction of the wafer;
a tape transfer mechanism that stretches the polishing tape wound around the first roller and the second roller between the first roller and the second roller and transfers the polishing tape between the first roller and the second roller;
a roller moving mechanism that moves each of the first roller and the second roller independently in a direction toward and away from the edge surface of the wafer, and moves the polishing tape in a direction toward and away from the edge surface of the wafer;
Equipped with
The roller moving mechanism includes:
moving both or either one of the first roller and the second roller in a direction approaching an edge surface of the wafer supported by the wafer rotation mechanism, and polishing the edge surface of the wafer with the polishing tape being transferred between the first roller and the second roller;
The wafer lifting mechanism includes:
The wafer edge polishing apparatus changes the position of the edge of the wafer with which the polishing tape comes into contact in the thickness direction of the wafer by raising and lowering the wafer.
a back pad having a surface portion is provided between the first roller and the second roller,
2. The wafer edge polishing apparatus of claim 1, wherein the back pad supports the polishing tape transported between the first roller and the second roller with the surface portion and presses the polishing tape supported by the surface portion against the edge portion of the wafer.
The wafer lifting mechanism includes:
2. The wafer edge polishing apparatus according to claim 1, wherein the height position of the wafer is determined based on an inspection result of the shape of the edge of the wafer obtained by a wafer edge inspection apparatus for inspecting the shape of the edge of the wafer.
The tape transport mechanism is provided as a first tape transport mechanism, and the polishing tape is provided as a first polishing tape; and
a third roller disposed radially outward of the wafer supported by the wafer rotation mechanism;
a fourth roller disposed radially outward of the wafer supported by the wafer rotation mechanism and opposed to the third roller in a thickness direction of the wafer;
a second tape transport mechanism that winds a second polishing tape having a roughness different from that of the first polishing tape around the third roller and the fourth roller, stretches the second polishing tape between the third roller and the fourth roller, and transports the second polishing tape between the third roller and the fourth roller;
a tape switching mechanism that moves a first roller group consisting of the first roller and the second roller and a second roller group consisting of the third roller and the fourth roller relative to the wafer, thereby bringing the first polishing tape or the second polishing tape into sliding contact with the edge surface of the wafer;
The wafer edge polishing apparatus according to claim 1 , comprising:
a base plate on which the tape transport mechanism and the roller movement mechanism are provided;
a load sensor provided on the base plate and configured to detect a load applied from the wafer to the polishing tape when the polishing tape is brought into contact with the edge surface of the wafer;
Equipped with
The base plate is
2. The wafer edge polishing apparatus according to claim 1, further comprising a load sensor for detecting a load on said wafer edge, said load sensor detecting a load on said wafer edge, and said load sensor detecting a load on said wafer edge.
The roller moving mechanism includes:
a first moving plate having the first roller at its tip;
a second moving plate disposed opposite the first moving plate and having the second roller at a tip thereof;
a pair of engagement portions provided on opposing surfaces of the first moving plate and the second moving plate,
an engaging rotation portion that engages with each of the pair of engaging portions;
A drive unit that rotates the engagement rotation unit;
The wafer edge polishing apparatus according to claim 1 , comprising: