Wafer clamping apparatus and processing apparatus

Abstract

To provide a wafer clamping device that eliminates the need to detect a deviation between the rotation center of a chuck table and the center of a wafer and to perform control for bringing a cutting blade close to and away from the rotation axis of the chuck table in accordance with the deviation, and solves the problem that a load is applied to the cutting blade.SOLUTION: The gripping part moving means includes a base 742 having a guide part 742a for guiding the movement of the gripping part, a motor 748 having a rotation shaft positioned at the 748a of the base, an arm 745 connected to the gripping part from the rotation shaft center of the motor, a load detection part 110 for detecting a load of the motor, and a control part 120 for controlling a gripping force so that the load becomes a predetermined value, when the outer circumference of the wafer is clamped by the clamping part, the rotation axis of the motor and the center of the wafer coincide with each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a wafer clamping device for clamping a circular wafer and a processing device for a wafer having a chamfered portion on the outer periphery. [Background technology]

[0002] A wafer has a plurality of devices such as ICs and LSIs formed on its surface, separated by planned dividing lines. The back surface is ground by a grinding machine to form the wafer to a predetermined thickness, and then the wafer is divided into individual device chips by a dicing machine, which are then used in electrical equipment such as mobile phones and personal computers.

[0003] The grinding device includes a chuck table for holding a wafer and grinding means having a rotatably mounted grinding wheel for grinding the wafer held on the chuck table, and is capable of grinding the wafer to a desired thickness.

[0004] However, when a chamfer is formed on the outer periphery of a wafer and the wafer is ground thinly, the chamfer becomes as sharp as a knife edge, which is dangerous, and there is also the problem that cracks may form from the knife edge and penetrate into the interior of the wafer, damaging the wafer.

[0005] Therefore, the present applicant has developed and proposed a technique for removing the chamfered portion of the wafer before grinding the back surface of the wafer (see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-106689 Summary of the Invention [Problem to be solved by the invention]

[0007] In the prior art, when removing the chamfered portion of the outer periphery of the wafer with a uniform width, it is necessary to rotate the chuck table while imaging the outer periphery of the wafer with an imaging means, detect the direction and amount of deviation between the center of rotation of the chuck table and the center of the wafer, and then move the cutting means equipped with a cutting blade toward or away from the rotation axis of the chuck table in accordance with the detected deviation to perform cutting, which results in poor productivity. Furthermore, performing such cutting processing places a load on the cutting blade, which can also cause problems such as an adverse effect on the life of the cutting blade.

[0008] The present invention has been made in consideration of the above facts, and its main technical object is to provide a wafer clamping device and a wafer processing device having a chamfered portion on the outer periphery that can solve the problems of needing to detect the deviation between the center of rotation of the chuck table and the center of the wafer and to control the cutting means equipped with a cutting blade to move toward and away from the rotation axis of the chuck table in response to the deviation, and the problem of load being placed on the cutting blade. [Means for solving the problem]

[0009] In order to solve the above-mentioned main technical problem, according to the present invention, there is provided a wafer clamping device for clamping a circular wafer, comprising at least three clamping parts that contact the outer periphery of the wafer and clamp the wafer, and clamping part moving means for moving the clamping parts toward the center of the wafer, wherein the clamping part moving means comprises a base with guide parts that radially guide the movement of the clamping parts, a motor whose rotation axis is positioned at the center of the base, an arm connected to the rotation axis of the motor and the clamping parts, a load detection part that detects the load of the motor, and a control part that controls the wafer clamping force so that the load detected by the load detection part becomes a predetermined value, and a wafer clamping device is provided in which, when the outer periphery of the wafer is clamped by the clamping parts, the rotation axis of the motor coincides with the center of the wafer.

[0010] The control unit preferably detects the outer diameter of the wafer from the rotation angle of the motor.

[0011] Furthermore, according to the present invention, there is provided a processing apparatus for processing a wafer having a chamfered portion on its outer periphery, comprising: a rotatable chuck table for holding a wafer; cutting means for positioning a cutting blade on the outer periphery of the wafer held on the chuck table to remove the chamfered portion; advancing and retreating means for moving the cutting means back and forth relative to the rotation axis of the chuck table; and transport means for transporting the wafer and placing it on the chuck table, wherein the transport means is equipped with the above-mentioned wafer clamping device, and the processing apparatus places the wafer on the chuck table at a position where the rotation axis of the chuck table coincides with the rotation axis of a motor constituting the wafer clamping device.

[0012] It is preferable that the conveying means is equipped with a wafer clamping device including a control unit that detects the outer diameter of the wafer from the rotation angle of the motor as described above, and that the outer diameter of the wafer is detected to operate the advancing / retreating means to position the cutting blade at a desired position from the outer periphery of the wafer placed on the chuck table. [Effects of the Invention]

[0013] The wafer clamping device of the present invention includes at least three clamping sections that contact the outer periphery of a wafer and clamp the wafer, and clamping section moving means that moves the clamping sections toward the center of the wafer, the clamping section moving means including a base with guide sections that radially guide the movement of the clamping sections, a motor whose rotation axis is positioned at the center of the base, an arm connected to the rotation axis of the motor and the clamping sections, a load detection section that detects the load of the motor, and a control section that controls the wafer clamping force so that the load detected by the load detection section becomes a predetermined value, and when the outer periphery of the wafer is clamped by the clamping sections, the rotation axis of the motor and the center of the wafer are aligned. Since the axes of the wafer and the chuck table are aligned, by clamping the wafer and transporting it to the chuck table, it is possible to align the center of the wafer with the rotation axis of the chuck table and hold it by suction. This eliminates the need to rotate the chuck table while imaging the outer periphery of the wafer with the imaging means, detect the direction and amount of deviation between the rotation axis of the chuck table and the center of the wafer, and control the cutting means equipped with a cutting blade to move toward and away from the rotation axis of the chuck table in accordance with the detected deviation, as in the conventional technology, thereby eliminating the problems of long wafer processing times, poor productivity, and load on the cutting blade.

[0014] The processing apparatus of the present invention is configured to include a rotatable chuck table that holds a wafer, cutting means that positions a cutting blade on the outer periphery of the wafer held on the chuck table to remove a chamfered portion, advancing and retreating means that moves the cutting means back and forth relative to the rotation axis of the chuck table, and transport means that transports the wafer and places it on the chuck table, and the transport means is equipped with the wafer clamping device described above, and places the wafer on the chuck table at a position where the rotation axis of the chuck table coincides with the rotation axis of a motor that constitutes the wafer clamping device, thereby clamping the wafer. By transporting the wafer to the chuck table, it is possible to align the center of the wafer with the rotation axis of the chuck table and hold it by suction, and there is no need to rotate the chuck table while imaging the outer periphery of the wafer with an imaging means, detect the direction and amount of deviation between the rotation axis of the chuck table and the center of the wafer, and control the cutting means equipped with a cutting blade to move closer to or away from the rotation axis of the chuck table in response to the detected deviation, as in conventional technology, thereby eliminating the problems of long wafer processing times, poor productivity, and strain on the cutting blade. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is an overall perspective view of a processing device according to an embodiment of the present invention; [Figure 2] 2 is a perspective view of a transport means equipped with a wafer clamping device mounted on the processing apparatus shown in FIG. 1. FIG. [Figure 3] 3 is an exploded perspective view of a wafer clamping device mounted on the conveying means shown in FIG. 2 and the wafer clamping device. FIG. [Figure 4] 4 is a perspective view showing a manner in which a clamping section is moved by a clamping section moving means of the wafer clamping device shown in FIG. 3. FIG. [Figure 5] FIG. 10 is a perspective view showing a mode in which the wafer clamping device is brought close to the wafer. [Figure 6] FIG. 10 is a perspective view showing a state in which the wafer clamping device is positioned at a height at which it clamps the wafer. [Figure 7]10 is a perspective view showing a mode in which the wafer is clamped by the clamping parts by operating the clamping part moving means. FIG. [Figure 8] FIG. 10 is a perspective view showing a state in which a wafer is transferred onto a chuck table by a wafer clamping device. [Figure 9] FIG. 10 is a perspective view showing a state in which a wafer is suction-held by a chuck table. [Figure 10] 1A is a perspective view showing an embodiment of cutting work for removing a chamfered portion from the outer periphery of a wafer, and FIG. 1B is an enlarged side view showing a part of the cutting work shown in FIG. 1A. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a wafer clamping device configured based on the present invention for clamping a circular wafer, and an embodiment of a wafer processing device equipped with the wafer clamping device and having a chamfered portion on the outer periphery will be described in detail with reference to the accompanying drawings.

[0017] 1 shows an overall perspective view of a wafer processing apparatus 2 including a wafer clamping device 7 configured according to the present invention. The workpiece processed by the processing apparatus 2 of this embodiment is, for example, a semiconductor wafer W as shown in the figure, which has a plurality of devices D formed on its surface and a chamfered portion formed on its outer periphery Wa.

[0018] The illustrated processing device 2 includes a housing 3 having a substantially rectangular parallelepiped shape, a cassette 4 (shown by a two-dot chain line) placed on a cassette table 4a configured to be freely raised and lowered in the housing 3, a loading / unloading means 5 for carrying out unprocessed wafers W from the cassette 4 and carrying processed wafers W into the cassette 4, a transport means 6 equipped with a wafer clamping device 7 and having a swivel arm 62 for transporting wafers W clamped by the wafer clamping device 7, a chuck table 8 configured to be rotatable and equipped with a holding surface 8a for holding the wafers W transported by the transport means 6, and The processing device 2 is equipped with a cutting means 9 that performs cutting processing on the wafer W held on the chuck table 8, an alignment means 10 that takes an image of the wafer W held on the chuck table 8 and detects the area to be cut by the cutting means 9, a cleaning device 11 (internal details are omitted) that cleans and dries the wafer W after processing, and a cleaning and unloading means 12 that transports the wafer W from the loading / unloading position where the chuck table 8 is positioned in Figure 1 to the cleaning device 11, as well as a control means 100 that controls each operating part of the processing device 2 and a display means (not shown), etc.

[0019] The loading / unloading means 5 is equipped with an adsorption portion 5a that adsorbs the wafer W, and can be moved in the Y-axis direction in the figure by a driving means not shown.The adsorption portion 5a is inserted through an opening not shown in the cassette 4 positioned at a predetermined height by the cassette table 4a, and positioned on the underside of the wafer W stored at the predetermined height.The wafer W is then sucked up by the negative pressure generated in multiple suction holes 5b formed in the adsorption portion 5a, and is then transported out of the cassette 4.

[0020] FIG. 2 shows an enlarged view of the transport means 6 provided in the processing apparatus 2 shown in FIG. 1. A wafer clamping device 7 is provided at the tip 62a of a swivel arm 62 constituting the transport means 6. The swivel arm 62 is driven by a rotation drive means (not shown) to rotate around a rotation shaft 62b in the direction indicated by the arrow R1 in the figure and also move up and down. The transport means 6 clamps the wafer W carried out by the carry-in / out means 5 with the wafer clamping device 7 and rotates the swivel arm 62 to transport it to the chuck table 8 shown in FIG. 1, and can also clamp the processed wafer W that has been cleaned and dried in the cleaning device 11 and transport it to the carry-in / out means 5. The processed wafer W transported to the carry-in / out means 5 is attracted by the suction portion 5a of the carry-in / out means 5 and stored in the desired position in the cassette 4.

[0021] Returning to Figure 1 to continue the explanation, the cutting means 9 is a means (described in detail later) for positioning a cutting blade 95 on the outer periphery Wa of the wafer W held on the chuck table 8 to remove the chamfered portion, and is equipped with an advancing / retreating means (not shown) for advancing / retreating the cutting means 9 relative to the rotation axis of the chuck table 8 positioned in the cutting processing area adjacent to the cutting means 9 in the Y-axis direction.

[0022] The cleaning and carrying-out means 12 includes a transfer arm 12a and a suction unit 12b disposed at the tip of the transfer arm 12a. The transfer arm 12a is configured to be movable in the Y-axis direction by a driving unit (not shown) housed in the housing 3, and the suction unit 12b is configured to be able to move up and down in the vertical direction (Z-axis direction). A plurality of suction holes (not shown) are formed on the underside of the suction unit 12b, and the wafer W machined by the cutting means 9 and held on the chuck table 8 positioned at the carry-in / out position can be sucked and carried to the cleaning device 11.

[0023] The wafer clamping device 7 disposed on the transport means 6 will be described in more detail with reference to Fig. 3. The left side of Fig. 3 shows an enlarged view of the wafer clamping device 7, and the right side shows an exploded perspective view of the wafer clamping device 7. For convenience of explanation, the wafer clamping device 7 shown in Fig. 3 is shown without the swivel arm 62.

[0024] 3, the wafer clamping device 7 is configured to include three clamping sections 72 that contact the outer periphery of the wafer W to clamp the wafer W, and a clamping section moving means 74 that moves the clamping sections 72 toward the center of the wafer W. Claw sections 722 for holding the outer periphery Wa of the wafer W are formed on the underside of the tip end of the clamping sections 72, and pin mounting holes 72a into which connecting pins 724, described below, are press-fitted are formed on the rear end side of the clamping sections 72. As can be seen from the enlarged view of a portion of the claw sections 722 shown below, recesses 722a for holding the outer periphery Wa of the wafer W are formed on the inside of the tip end of the claw sections 722.

[0025] The clamping unit moving means 74 includes a base 742 having guide units 742a that radially guide the movement of the three clamping units 72 described above, a motor 748 whose axis of rotation 748a is positioned at the center P1 of the base 742, and an arm 745 connected from the rotation shaft 748a of the motor 748 to the clamping units 72.

[0026] The three guide portions 742a of the base 742 are formed on straight lines extending radially at equal intervals of 120 degrees from point P1, which indicates the center of the base 742, and are open in the vertical direction. On the lower surface side of the guide portions 742a formed on the base 742, slide holes 742c are formed, into which the clamping portion 72 is slidably inserted.

[0027] When setting the clamping portion 72 on the base 742, the rear end of the clamping portion 72 is inserted into the slide hole 742c, and the tip of the connecting pin 724 inserted from the guide portion 742a side is fixed to the pin mounting hole 72a formed on the rear end side of the clamping portion 72.

[0028] The connecting pins 724 fixed to the rear end sides of the three clamping parts 72 described above engage with engaging holes 745a formed at one end of three arms 745 shown in the figure. The other end of each arm 745 is engaged by a predetermined connecting member (not shown) with engaging holes 744b formed at three equally spaced locations on the outer periphery of the illustrated circular plate 744. A fixing hole 744a is formed in the center of the circular plate 744, to which a tip end 748b of a rotating shaft 748a of the motor 748 is fixed.

[0029] The motor 748 is mounted on a pedestal 746 disposed in the center of the base 742, with its rotation shaft 748a pointing downward. The pedestal 746 includes a disk-shaped plate 746a forming the upper surface, and three legs 746b disposed on the lower surface of the outer periphery of the plate 746a, and an opening 746c is formed in the center of the plate 746a, into which the rotation shaft 748a of the motor 748 is inserted. Note that the tip 62a of the swivel arm 62 of the transport means 6 described above is fixed to the upper surface of the plate 746a of the pedestal 746 (for convenience of explanation, the swivel arm 62 is omitted).

[0030] After the clamping unit 72 is attached to the base 742 as described above, the rotating shaft 748a of the motor 748 is inserted into the opening 746c of the pedestal 746 to fix the motor 748 to the plate 746a of the pedestal 746, and the tip 748b of the rotating shaft 748a is fixed to the fixing hole 744a of the annular plate 744. The fixing method is not particularly limited, but for example, the tip 748b of the rotating shaft 748a is press-fitted into the fixing hole 744a of the annular plate 744 to fix it. As a result, the rotating shaft 748a of the motor 748 is connected to the clamping unit 72 via the annular plate 744 and the arm 745. Then, the three legs 746b of the pedestal 746 are fixed to fixing portions 742b formed on the base 742 at intermediate positions between two adjacent guide portions 742a.

[0031] As shown on the left side of Fig. 3, the direction of arm 745 coincides with the direction in which clamping unit 72 moves along guide portion 742a, and the three claws 722 are positioned outermost, which is the standby state of clamping unit 72. In contrast, as shown in Fig. 4, by rotating rotation shaft 748a of motor 748 in the direction indicated by arrow R2 in the figure, the circular plate 744 rotates within base portion 746, and the arm 745 is pulled in the rotation direction of circular plate 744 indicated by arrow R2 in conjunction with the rotation of circular plate 744. As a result, clamping unit 72 connected to arm 745 slides from the standby state in the direction indicated by arrow R3 along guide portion 742a, and the claws 722 move toward the center of base 742. The three clamping parts 72 described above have the same length, and the three clamping parts 72 move by the same amount when the rotation shaft 748a of the motor 748 is rotated to rotate the annular plate 744. As a result, when the outer periphery of the circular wafer W is clamped by the three clamping parts 72 described above, the axis of the rotation shaft 748a of the motor 748 and the center of the wafer W coincide with each other.

[0032] The transport means 6 of the present embodiment described above is configured so that when the swivel arm 62 disposed in the transport means 6 is swiveled to move the wafer clamping device 7 disposed at the tip 62a of the swivel arm 62 onto the chuck table 8 positioned at the load / unload position of the processing device 2, the axis of the rotation shaft 748a of the motor 748 of the clamping unit moving means 74 coincides with the rotation axis of the chuck table 8. In other words, by operating the transport means 6 to clamp the wafer W with the wafer clamping device 7 and transport it to the chuck table 8 positioned at the load / unload position of the processing device 2, the center of the wafer W is accurately positioned on the rotation axis of the chuck table 8.

[0033] The control means 100 is configured by a computer and includes a central processing unit (CPU) that performs calculations according to a control program, a read-only memory (ROM) that stores the control program, etc., a readable and writable random access memory (RAM) that temporarily stores detected values, calculation results, etc., and an input interface and an output interface (details not shown). The control means 100 is connected to the above-mentioned carry-in / out means 5, transport means 6, wafer clamping device 7, cutting means 9, alignment means 10, display means (not shown), etc.

[0034] 3, the motor 748 of the wafer clamping device 7 is connected to a control means 100. The control means 100 is configured with a load detection unit 110 that detects the load (load current value) of the motor 748, and a control unit 120 that controls the clamping force of the wafer W so that the load detected by the load detection unit 110 becomes a predetermined value. Note that the load detection unit 110 and the control unit 120 are not limited to being disposed in the control means 100 that controls the respective operating units of the processing apparatus 2, and may be provided separately from the control means 100.

[0035] The motor 748 is, for example, a stepping motor. When the clamping unit 72 moves from the standby position described above along the guide unit 742a toward the center of the base 742 due to rotation of the rotation shaft 748a of the motor 748, the position of the claws 722 is identified based on the rotation angle of the motor 748. While the above-described embodiment illustrates an example in which three clamping units 72 are provided, the present invention is not limited to this, and four or more clamping units 72 may be provided. Even when four or more clamping units 72 are provided, similar to the above-described embodiment, the clamping units 72 are formed to have the same length, and are configured so that the amount of movement of each clamping unit 72 is the same when the rotation shaft 748a of the motor 748 is rotated to rotate the annular plate 744.

[0036] The wafer clamping device 7 of this embodiment and the processing device 2 equipped with the wafer clamping device 7 have roughly the configuration as described above, and their functions, actions and effects will be described below with reference to Figures 5 to 10 in addition to Figure 1.

[0037] The wafer W, which is the workpiece of the processing device 2, is, for example, a silicon wafer having a thickness of 500 μm and a diameter of 200 mm. When processing this wafer W, the suction portion 5a of the loading / unloading means 5 sucks and unloads the wafer W stored in the cassette 4. After the wafer W is unloaded by the loading / unloading means 5, the swivel arm 62 of the transport means 6 rotates to position the wafer clamping device 7 so that the center of the wafer W and the axis of the rotation shaft 748a of the motor 748 of the clamping portion moving means 74 are substantially aligned, as shown in FIG. 5 . At this time, the three clamping portions 72 of the wafer clamping device 7 are positioned outermost and in a standby state.

[0038] As described above, once the wafer clamping device 7 is positioned above the wafer W adsorbed by the adsorption portion 5a of the loading / unloading means 5, the wafer clamping device 7 is lowered in the direction indicated by the arrow R4 in FIG. 5, and positioned at a height where the outer periphery Wa of the wafer W can be clamped by the claw portions 722 of the clamping portion 72, as shown in FIG. 6.

[0039] Next, the suction of the suction portion 5a is released to free the wafer W, and the motor 748 of the clamping portion moving means 74 is operated to rotate the rotation shaft 748a in the direction indicated by arrow R2, as shown in Fig. 7. This causes the clamping portion 72 to move along the guide portion 742a toward the center of the base 742 indicated by arrow R3, and the recessed portion 722a of the claw portion 722 of the clamping portion 72 comes into contact with the outer periphery Wa of the wafer W, as shown on the right side of Fig. 7.

[0040] As described above, the motor 748 is connected to the control means 100, and the load of the motor 748, i.e., the load current value, can be detected by the load detection unit 110 configured in the control means 100. Therefore, by determining an increase in the load current value, it is detected that the recesses 722a of the claws 722 of the clamping unit 72 have come into contact with the outer periphery Wa of the wafer W. Then, with the load current value maintained at a predetermined value, the axial center of the rotation shaft 748a of the motor 748 and the center of the wafer W are aligned.

[0041] Furthermore, when the load detection unit 110 detects an increase in the load current value and the wafer W is clamped by the clamping unit 72 of the wafer clamping device 7, the control unit 120 identifies the position of the clamping unit 72 based on the rotation angle of the motor 748, detects the outer diameter of the wafer W, and stores it in an appropriate memory of the control means 100.

[0042] Once the wafer W has been clamped by the claws 722 of the clamping unit 72 as described above, the rotating arm 62 of the transport means 6 is operated to lift the wafer clamping device 7 in the direction indicated by arrow R5 in Fig. 7 and move it onto the chuck table 8 positioned at the load / unload position of the processing device 2, as shown in Fig. 8. At this time, the wafer clamping device 7 is positioned so that the axis of the rotation shaft 748a of the motor 748 of the clamping unit moving means 74 coincides with the rotation axis of the chuck table 8, and as a result, the center of the wafer W clamped by the wafer clamping device 7 coincides with the rotation axis of the chuck table 8.

[0043] Once the wafer W is positioned on the chuck table 8, the transport means 6 is operated to lower the wafer clamping device 7 in the direction indicated by arrow R6 in Fig. 8, so that the wafer W is positioned on the holding surface 8a of the chuck table 8. Next, as shown in Fig. 9, a suction means (not shown) connected to the chuck table 8 is operated to supply a negative suction pressure V to the chuck table 8, thereby sucking the wafer W onto the holding surface 8a. In response to this, the motor 748 of the clamping unit moving means 74 is operated to move the clamping unit 72 in the direction indicated by arrow R7 in Fig. 9, thereby placing the clamping unit 72 in the standby state described above, and the wafer clamping device 7 is raised in the direction indicated by arrow R8 in the figure, so that the wafer clamping device 7 is separated from the chuck table 8 that holds the wafer W by suction. As a result, the wafer W is held by suction on the chuck table 8 with the rotation axis of the chuck table 8 and the center of the wafer W aligned.

[0044] Once the wafer W is held on the chuck table 8 as described above, the X-axis feed means (not shown) is operated to position the wafer W directly below the alignment means 10 shown in Fig. 1, where an image of the wafer W is taken and the surface height of the wafer W is detected. Then, as shown in Fig. 10(a), the chuck table 8 is positioned in a cutting processing area where cutting processing is performed by the cutting means 9. Next, based on the outer diameter of the wafer W detected when the wafer W is clamped by the clamping section 72, the advancing / retracting means is operated to position the cutting means 9 at a desired position from the outer periphery Wa of the wafer W, for example, 3 mm from the end of the outer periphery Wa.

[0045] As shown in Figure 10(a), the cutting means 9 comprises a spindle housing 92 arranged in the Y-axis direction indicated by the arrow Y in the figure, a spindle 94 rotatably held in the spindle housing 92, an annular cutting blade 95 held at the tip of the spindle 94, a blade cover 96 that covers the cutting blade 95, and a cutting water supply nozzle 97 arranged on the blade cover 96 that supplies cutting water to the cutting area by the cutting blade 95, as well as an advance / retract means for indexing and feeding the cutting blade 95 in the Y-axis direction and a spindle motor for driving the spindle 94 (both not shown).

[0046] The illustrated processing apparatus 2 performs a cutting process to remove a chamfered portion formed on the outer periphery Wa of the wafer W. The cutting means 9 is moved in the Y-axis direction by operating the advancing / retracting means described above, and the cutting blade 95 is positioned at the desired position where the chamfered portion is formed on the outer periphery Wa of the wafer W, which is placed and held by suction on the chuck table 8. The cutting blade 95 is then rotated at high speed in the direction indicated by arrow R9 in the figure, while the chuck table 8 is rotated in the direction indicated by arrow R10. While supplying cutting water from the cutting water supply nozzle 97, the cutting blade 95 is cut downward from the surface of the wafer W, as indicated by arrow R11, as shown in FIG. 10(b), depending on the depth of the chamfer to be removed, to form a step Wb by removing a required amount of the chamfered portion from the entire outer periphery Wa of the wafer W. As described above, the process is not limited to forming a step Wb, and the entire outer periphery Wa, including the chamfered portion, may be removed.

[0047] According to the above-described embodiment, by clamping the wafer W using the wafer clamping device 7 configured based on the present invention and transporting it to the chuck table 8, it is possible to align the center of the wafer W with the rotation axis of the chuck table 8 and hold it by suction. This eliminates the need to rotate the chuck table while imaging the outer periphery of the wafer with an imaging means, detect the direction and amount of deviation between the rotation axis of the chuck table and the center of the wafer, and control the cutting means 9 equipped with the cutting blade 95 to move closer to and away from the rotation axis of the chuck table 8 in accordance with the detected deviation, as in the conventional technology. This eliminates the problems of time-consuming processing of the wafer W, poor productivity, and load on the cutting blade.

[0048] Furthermore, by clamping the wafer W with the wafer clamping device 7 described above, it is possible to detect the outer diameter of the wafer W, and by operating the advancing / retracting means based on the detected outer diameter, it is possible to position the cutting blade 95 at a desired position from the outer periphery Wa of the wafer W placed on the chuck table 8. Furthermore, by detecting the actual outer diameter of the wafer W as described above, it becomes possible to quickly discover errors before actual processing begins, for example, when an operator erroneously inputs the outer diameter of the wafer W when instructing the processing device 2 to process the wafer W, or when a wafer with an outer diameter different from the wafer W to be processed is mistakenly loaded into the processing device 2.

[0049] In the above embodiment, an example was shown in which the wafer clamping device 7 configured according to the present invention was applied to a processing device 2 that removes a chamfered portion of a wafer W having a chamfered portion on its outer periphery Wa. However, the wafer clamping device 7 configured according to the present invention is not limited to being applied to the processing device 2 described above, and can be applied to other processing devices that need to clamp a circular wafer. For example, the present invention can be applied to a cutting device that cuts a wafer having a plurality of devices defined by dividing lines formed on its surface along the dividing lines to divide the wafer into individual chips, a laser processing device that irradiates the wafer with a laser beam along the dividing lines to form laser-processed grooves that serve as starting points for division, and a grinding device that grinds the back surface of a wafer to a desired thickness. [Explanation of symbols]

[0050] 2: Processing equipment 3: Housing 4: Cassette 5: Carrying in / out means 5a: Adsorption part 6: Means of transport 62: Swivel arm 7: Wafer holding device 72: Holding part 722: Claw part 722a: Recess 74: Holding part moving means 742: Foundation 742a: Guide section 742b: Fixed part 744: Circular plate 744a: Fixed hole 744b: Engagement pin 745: Arm 745a: Engagement hole 746: Base 746a: Plate 746b: Legs 746c: opening 748:Motor 748a: Rotating axis 8: Chuck table 9:Cutting means 92: Spindle housing 94: Spindle 95: Cutting blade 96: Blade cover 97: Cutting water supply nozzle 10: Alignment means 11: Cleaning equipment 12: Cleaning transport means 12a: Transfer arm 12b: Adsorption part 100: Control means 110: Load detection unit 120: Control unit D:Device W: Wafer Wa: perimeter

Claims

1. A wafer clamping device for clamping a circular wafer, at least three clamping portions that contact the outer periphery of the wafer and clamp the wafer; a clamping unit moving means for moving the clamping unit toward the center of the wafer; Including, the clamping unit moving means comprises: a base having guide units for radially guiding the movement of the clamping unit; a motor having a rotation shaft positioned at the center of the base; an arm connected to the rotation shaft of the motor from the clamping unit; a load detection unit for detecting a load on the motor; and a control unit for controlling the wafer clamping force so that the load detected by the load detection unit becomes a predetermined value; A wafer clamping device in which, when the outer periphery of the wafer is clamped by the clamping portion, the rotation axis of the motor coincides with the center of the wafer.

2. 2. The wafer clamping device according to claim 1, wherein the control unit detects the outer diameter of the wafer from the rotation angle of the motor.

3. A processing device for a wafer having a chamfered portion on the outer periphery, The wafer processing apparatus includes a rotatable chuck table for holding a wafer, cutting means for positioning a cutting blade on the outer periphery of the wafer held on the chuck table to remove a chamfered portion, advancing and retreating means for advancing and retreating the cutting means relative to the rotation axis of the chuck table, and transport means for transporting the wafer and placing it on the chuck table, The conveying means is a processing apparatus that includes the wafer clamping device according to claim 1, and places the wafer on the chuck table at a position where the rotation axis of the chuck table coincides with the rotation axis of a motor that constitutes the wafer clamping device.

4. 4. The processing apparatus according to claim 3, wherein the conveying means is provided with the wafer clamping device according to claim 2, detects the outer diameter of the wafer, operates the advancing / retracting means, and positions the cutting blade at a desired position from the outer periphery of the wafer placed on the chuck table.

Images