Machining apparatus

Abstract

To provide a wafer clamping device capable of reducing control operation and improving productivity, and a wafer processing device having a chamfered part on the outer periphery.SOLUTION: The conveying mechanism includes a guide part 742a for radially guiding the movement of the clamping part 72 from the central axis of the base, a motor 748 for moving the clamping part 72, a load detector 110 for detecting the load of the motor 748, and a controller 120 for controlling the clamping force for clamping the wafer so that the load detected by the load detector 110 becomes a predetermined value. The outer periphery of the wafer is clamped by the clamping part 72 to align the center axis of the base 742 with the center of the wafer, and the center axis P1 of the base 742 is aligned with the rotation axis of the chuck table to place the wafer thereon, and the control part 120 detects the outer diameter of the wafer based on the amount of rotation of the motor 748, and operates the advancing and retracting means to position the cutting blade at a desired position from the outer periphery of the wafer placed on the chuck table.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to 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] The above-described conventional technology requires detecting the misalignment between the rotation axis of the chuck table and the center of the wafer, and when the misalignment occurs, controlling the cutting means equipped with the cutting blade to move toward or away from the rotation axis of the chuck table in response to the misalignment, which results in poor productivity. Furthermore, performing such cutting processing places a load on the cutting blade, which can have a negative effect on the life of the cutting blade.

[0008] The present invention has been made in consideration of the above-mentioned facts, and its main technical object is to provide a wafer processing device that can solve the problem of needing to detect the deviation between the rotation axis 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, as well as the problem of a 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 an 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 advancing and retreating the cutting means relative to the rotation axis of the chuck table; and a transport mechanism for transporting the wafer and placing it on the chuck table, wherein the transport mechanism comprises a base having a central axis, and centering means disposed on the base for clamping the outer periphery of the wafer to align the center of the wafer with the central axis, and the centering means comprises at least three clamping members for clamping the outer periphery of the wafer, and A processing apparatus is provided which includes a guide section which guides the movement of the clamping section radially from the central axis of the base, a motor which moves the clamping section, a load detection section which detects the load on the motor, and a control section which controls the clamping force which clamps the wafer so that the load detected by the load detection section becomes a predetermined value, wherein the outer periphery of the wafer is clamped by the clamping section to align the center of the wafer with the central axis of the base and the central axis of the base is aligned with the rotation axis of the chuck table so that the wafer is placed on it, and the control section detects the outer diameter of the wafer from the amount of rotation of the motor and operates the advancing / retracting means to position the cutting blade at a desired position from the outer periphery of the wafer placed on the chuck table.

[0010] The centering means preferably includes a single motor whose rotation axis coincides with the center axis of the base, and arms connected from the rotation axis of the motor to each of the clamping portions. [Effects of the Invention]

[0011] The processing apparatus of the present invention 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 moving the cutting means back and forth relative to the rotation axis of the chuck table, and a transport mechanism for transporting the wafer and placing it on the chuck table, the transport mechanism including a base having a central axis, and centering means disposed on the base for clamping the outer periphery of the wafer to align the center of the wafer with the central axis, the centering means including at least three clamping sections for clamping the outer periphery of the wafer, guide sections for guiding the movement of the clamping sections radially from the central axis of the base, a motor for moving the clamping sections, a load detection section for detecting the load on the motor, and a control section for controlling the clamping force for clamping the wafer so that the load detected by the load detection section becomes a predetermined value, and the outer periphery of the wafer is clamped by the clamping sections to align the wafer with the central axis of the base. The wafer is placed on the chuck table such that the center of the wafer is aligned with the center of the rotation axis of the chuck table and the central axis of the base is aligned with the rotation axis of the chuck table, and the control unit detects the outer diameter of the wafer from the amount of rotation of the motor and operates the advancing / retracting means to position the cutting blade at a desired position from the outer periphery of the wafer placed on the chuck table. This makes it possible to align the center of the wafer with the rotation axis of the chuck table, hold it by suction, and cut and remove the chamfered portion on the outer periphery of the wafer. 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 closer to and away from the rotation axis of the chuck table in accordance with the detected deviation, as in the prior art. This eliminates the problems of long wafer processing times, poor productivity, and load on the cutting blade. [Brief explanation of the drawings]

[0012] [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 transfer mechanism attached to the processing apparatus shown in FIG. 1. FIG. [Figure 3]3 is an exploded perspective view of a wafer clamping device attached to the transfer mechanism shown in FIG. 2. FIG. [Figure 4] 4 is a perspective view showing a mode in which a clamping part is moved by a center positioning means of the wafer clamping device shown in FIG. 3. FIG. [Figure 5] 4 is a perspective view showing a mode in which the wafer clamping device shown in FIG. 3 is brought close to the wafer. FIG. [Figure 6] 6 is a perspective view showing a state in which the wafer clamping device shown in FIG. 5 is positioned at a height at which it clamps a wafer. FIG. [Figure 7] 10 is a perspective view showing a mode in which the center positioning means of the wafer clamping device is activated to clamp the wafer by the clamping portion. FIG. [Figure 8] 3 is a perspective view showing a state in which the transfer mechanism shown in FIG. 2 is operated and the wafer held by the center positioning means is transferred onto the chuck table. FIG. [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

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a processing apparatus configured based on the present invention will be described in detail with reference to the accompanying drawings.

[0014] 1 shows an overall perspective view of a wafer processing apparatus 2 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.

[0015] The processing device 2 includes a rotatable chuck table 8 that holds the wafer W, a cutting means 9 that positions a cutting blade 95 on the outer periphery Wa of the wafer W held on the chuck table 8 to remove the chamfered portion, an advancing / retracting means (not shown) that moves the cutting means 9 back and forth relative to the rotation axis of the chuck table 8, and a transport mechanism 6 that transports the wafer W and places it on the chuck table 8.

[0016] In addition to the above-described configuration, the illustrated processing apparatus 2 includes a housing 3 having an approximately 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 unloading the unprocessed wafer W from the cassette 4 and loading the processed wafer W into the cassette 4, an alignment means 10 for imaging the wafer W held on the chuck table 8 described above and detecting the area to be cut by the cutting means 9 and the surface height of the wafer W, a cleaning device 11 (internal details are omitted) for cleaning and drying the processed wafer W, and a cleaning / unloading means 12 for transporting the wafer W to the cleaning device 11 from the loading / unloading position where the chuck table 8 is positioned in FIG. 1, as well as a control means 100 for controlling each operating part of the processing apparatus 2 and a display means (not shown).

[0017] 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 into the cassette 4 positioned at a predetermined height by the cassette table 4a through an opening not shown in the figure, and positioned on the underside of the wafer W stored at the predetermined height.The wafer W is then sucked in 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.

[0018] The chuck table 8 of this embodiment has a suction area divided into multiple concentric regions corresponding to multiple wafer sizes. The suction area includes a circular central suction area 8a and an annular outer periphery suction area 8b arranged concentrically around the central suction area 8a. The central suction area 8a and the outer periphery suction area 8b are divided by an annular partition 8c. The suction areas are surrounded by an outer periphery frame 8d. The outer diameter of the central suction area 8a is set to accommodate 6-inch wafers, and the outer diameter of the outer periphery suction area 8b is set to accommodate 8-inch wafers. The central suction area 8a and the outer periphery suction area 8b are made of permeable porous ceramics and are connected to a suction flow path and a suction source (not shown). The suction source is, for example, a suction pump, and by operating an appropriate switching valve on the suction flow path (not shown), it is possible to generate negative pressure only in the central suction region 8a to suck a 6-inch wafer, or to generate negative pressure in the central suction region 8a and the peripheral suction region 8b to suck an 8-inch wafer. In this embodiment, the chuck table 8 is divided into two regions to accommodate 6-inch and 8-inch wafers as described above, but it may also be divided into three or more regions to make a chuck table that can accommodate three or more types of wafers.

[0019] Figure 2 shows an enlarged view of the transport mechanism 6 arranged in the processing apparatus 2 shown in Figure 1, and the left side of Figure 3 shows a wafer clamping device 7 that forms part of the transport mechanism 6, while the right side of Figure 3 shows an exploded perspective view of the wafer clamping device 7.

[0020] 2, the transfer mechanism 6 has a swivel arm 62 that transfers the wafer W clamped by the wafer clamping device 7, and the swivel arm 62 is driven by a rotation drive means (not shown) to rotate about a rotation axis 62b in the direction indicated by arrow R1 in the figure and also move up and down. The transfer mechanism 6 can clamp the wafer W transferred by the transfer means 5 and rotate the swivel arm 62 to transfer 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 transfer it to the transfer means 5. The processed wafer W transferred to the transfer means 5 is attracted to the suction portion 5a of the transfer means 5 and stored in the desired position in the cassette 4.

[0021] 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 by operating the above-mentioned advancing / retracting means, the cutting means 9 is advanced / retracted 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] As can be seen from Figures 2 and 3, at the tip 62a of the swivel arm 62 that constitutes the transfer mechanism 6, there are provided a base 742 having a central axis P1, and a center positioning means 74 that is arranged on the base 742 and clamps the outer periphery Wa of the wafer W to align the center of the wafer W with the central axis P1.

[0024] The centering means 74 includes at least three clamping units 72 that clamp the outer periphery Wa of the wafer W, guide units 742a that guide the movement of the clamping units 72 radially from the central axis P1 of the base 742, a motor 748 that moves the clamping units 72, a load detection unit 110 that detects the load of the motor 748, and a control unit 120 that controls the clamping force of the clamping units 72 that clamp the wafer W so that the load detected by the load detection unit 110 becomes a predetermined value. The load detection unit 110 and the control unit 120 in this embodiment are disposed in the control unit 100 that controls the respective operating units of the processing apparatus 2. Note that the load detection unit 110 and the control unit 120 are not limited to being configured in the control unit 100, and may be provided separately from the control unit 100.

[0025] The centering means 74 will be described in more detail with reference to Figure 3. The centering means 74 has three arms 745 connected to the clamping unit 72 from a rotation shaft 748a of a motor 748. The three guide portions 742a of the base 742 are formed on straight lines extending radially at equal intervals of 120 degrees from the central axis P1 of the base 742, and are open in the vertical direction. Slide holes 742c into which the clamping unit 72 is slidably inserted are formed on the underside of the guide portions 742a formed on the base 742.

[0026] When attaching the clamping portion 72 to 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, which has been inserted from above the guide portion 742a, is inserted into the pin mounting hole 72a formed on the rear end of the clamping portion 72 and fixed.

[0027] The connecting pins 724 fixed to the rear end sides of the three clamping portions 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 a circular plate 744 as shown in the figure. 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 described above is fixed.

[0028] 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 mechanism 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).

[0029] Once the clamping unit 72 has been 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 circular plate 744. There are no particular limitations on the method for fixing the rotating shaft 748a to the circular plate 744, but for example, the tip 748b of the rotating shaft 748a can be press-fitted into the fixing hole 744a of the circular plate 744 to fix it. In this way, the rotating shaft 748a of the motor 748 is connected to the clamping unit 72 via the circular plate 744 and the arm 745. The three legs 746b of the pedestal 746 are fixed to a fixing portion 742b formed on the base 742 at a midpoint between two adjacent guide portions 742a.

[0030] 3, the longitudinal direction of the arm 745 coincides with the direction in which the clamping unit 72 moves along the guide portion 742a, and the three claws 722 of the clamping unit 72 are positioned outermost, which is the standby state of the clamping unit 72. In contrast, as shown in FIG. 4, by rotating the rotary shaft 748a of the motor 748 in the direction indicated by the arrow R2 in the figure, the circular plate 744 rotates within the base portion 746, and as the circular plate 744 rotates, the arm 745 is pulled in the rotational direction of the circular plate 744 indicated by the arrow R2, and the claws 722 of the clamping unit 72 connected to the arm 745 move from the standby state in the direction indicated by the arrow R3 along the guide portion 742a, i.e., toward the central axis P1 of the 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 claws 722 of the three clamping parts 72 described above, the central axis P1 of the base 742, i.e., the axis of the rotation shaft 748a of the motor 748, and the center of the wafer W coincide with each other.

[0031] The transfer mechanism 6 of the present embodiment described above is configured so that when the swivel arm 62 disposed in the transfer mechanism 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 described above coincides with the rotation axis of the chuck table 8. In other words, by operating the transfer mechanism 6 to clamp the wafer W by the center positioning means 74 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 with respect to the rotation axis of the chuck table 8.

[0032] 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, conveying mechanism 6, center positioning means 74, cutting means 9, alignment means 10, display means (not shown), etc.

[0033] 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 to clamp the wafer W by rotating the rotation shaft 748a of the motor 748, the position of the claws 722 is determined based on the rotation amount of the motor 748 at that time, more specifically, the rotation angle based on the number of pulses for driving the motor 748. Note that, although the above-described embodiment shows 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 lengths of the clamping units 72 are formed to be the same, and when the rotation shaft 748a of the motor 748 is rotated to rotate the annular plate 744, each clamping unit 72 moves toward the central axis P1 of the base 742, and the movement amounts of each clamping unit 72 are configured to be the same.

[0034] The processing device 2 equipped with the transport mechanism 6 of this embodiment has roughly the configuration as described above, and its functions, actions and effects will be described below with reference to Figs. 5 to 10 in addition to Fig. 1.

[0035] The wafer W, which is the workpiece of the processing device 2, is, for example, a silicon wafer, and when processing this wafer W, the suction portion 5a of the carry-in / out means 5 sucks and carries out the wafer W stored in the cassette 4. After the wafer W is carried out by the carry-in / out means 5, the swivel arm 62 of the transfer mechanism 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 center positioning means 74 are approximately aligned, as shown in Fig. 5. At this time, the three clamping portions 72 of the center positioning means 74 are positioned outermost and in a standby state.

[0036] As described above, once the wafer clamping device 7 is positioned above the wafer W carried out by the carrying-in / out means 5, it is lowered in the direction indicated by arrow R4 in FIG. 5 and positioned at a height where the outer periphery Wa of the wafer W can be clamped by the claws 722 of the clamping portion 72, as shown in FIG. 6.

[0037] Next, the suction of the suction portion 5a of the carry-in / out means 5 is released to free the wafer W, and as shown in Fig. 7, the motor 748 of the centering means 74 is operated to rotate the rotation shaft 748a of the motor 748 in the direction indicated by arrow R2. As a result, the arm 745 connected to the rotation shaft 748a is pulled in the direction indicated by arrow R2, and the clamping portion 72 moves in the direction indicated by arrow R3 along the guide portion 742a. ​​As a result, as shown in the lower right side of Fig. 7, the recessed portion 722a of the claw portion 722 of the clamping portion 72 abuts against the outer periphery Wa of the wafer W.

[0038] The motor 748 is connected to the load detection unit 110 described above, and is configured so that the load of the motor 748, i.e., the load current value, can be detected by the load detection unit 110. 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 chamfered portion on 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.

[0039] 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 amount of rotation of the motor 748, and precisely detects that the outer diameter of the wafer W is, for example, 8 inches (203.2 mm), and the detected value of the outer diameter of the wafer W is stored in an appropriate memory of the control means 100.

[0040] Once the wafer W has been clamped by the claws 722 of the clamping unit 72 as described above, the transport mechanism 6 is operated to lift the wafer W in the direction indicated by arrow R5 in Fig. 7 and move it onto the chuck table 8 positioned at the transfer position of the processing device 2, as shown in Fig. 8. At this time, the center of the rotation shaft 748a of the motor 748 of the centering means 74 is positioned so that it coincides with the rotation axis of the chuck table 8, so that the center of the wafer W clamped by the centering means 74 coincides with the rotation axis of the chuck table 8.

[0041] 8, the wafer clamping device 7 is lowered to position the wafer W on the chuck table 8. Next, based on information about the outer diameter of the wafer W (203.2 mm = 8 inches) stored in an appropriate memory of the control means 100, a suction means (not shown) connected to the chuck table 8 is operated to generate negative pressure in the central suction region 8a and the peripheral suction region 8b of the chuck table 8, thereby sucking and holding the wafer W on the chuck table 8. In conjunction with this, the motor 748 of the center positioning means 74 is operated to move the clamping unit 72 in the direction indicated by arrow R7 in FIG. 9 to enter the standby state described above, and the wafer clamping device 7 is raised in the direction indicated by arrow R8 in the figure to separate the wafer clamping device 7 from the chuck table 8 that is suction-holding the wafer W. As a result, the wafer W is sucked and held on the chuck table 8 in a state where the rotation axis of the chuck table 8 and the center of the wafer W coincide with each other.

[0042] In addition, if the wafer W clamped by the center positioning means 74 of the wafer clamping device 7 is 6 inches (152.4 mm), the outer diameter of the wafer W is detected to be 6 inches based on the amount of rotation of the rotating shaft 748a of the motor 748 when the wafer W is clamped by the clamping portion 72 of the center positioning means 74, and when the wafer W is transported to the chuck table 8 and held by suction, negative pressure is generated only in the central suction area 8a of the chuck table 8, and the wafer W is sucked and held.

[0043] 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, and an image of the wafer W is taken, and the surface height (e.g., 500 μm) of the wafer W is detected. Then, as shown in Fig. 10(a), the chuck table 8 is moved to the cutting processing area where cutting processing is performed by the cutting means 9, and the advancing / retracting means is operated based on the outer diameter of the wafer W detected by the center positioning means 74, to position the cutting blade 95 of 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.

[0044] 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).

[0045] As described above, the cutting blade 95 is positioned 3 mm from the edge of the outer periphery Wa of the wafer W placed on the chuck table 8 and held by suction. Then, the cutting blade 95 is rotated at high speed in the direction indicated by arrow R9 in the figure, and the chuck table 8 is rotated in the direction indicated by arrow R10. Then, cutting water is supplied from the cutting water supply nozzle 97, and the cutting blade 95 is moved downward from the surface of the wafer W in the direction 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 chamfer from the entire outer periphery Wa of the wafer W. The cutting process of this embodiment is not limited to forming the step Wb as shown in the figure, and cutting may be performed to remove the entire outer periphery Wa, including the chamfer.

[0046] According to the above-described embodiment, by clamping the wafer W using the center positioning means 74 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. Therefore, as in the conventional technology, it is no longer 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 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 or away from the rotation axis of the chuck table 8 in accordance with the detected deviation. This eliminates the problems of time-consuming processing of the wafer W, poor productivity, and load on the cutting blade.

[0047] Furthermore, according to this embodiment, the outer diameter of the wafer W can be detected by clamping the wafer W with the clamping portion 72 of the center positioning means 74 arranged in the conveying mechanism 6. Therefore, even if the wafers to be processed include a mixture of wafers of multiple sizes, for example, wafers with diameters of 8 inches and 6 inches, the advancing / retreating means can be appropriately operated based on the detected outer diameter, and the cutting blade 95 can be accurately positioned at the desired position from the outer periphery Wa of the wafer W placed on the chuck table 8.

[0048] 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 incorrectly 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. [Explanation of symbols]

[0049] 2: Processing equipment 3: Housing 4: Cassette 5: Carrying in / out means 5a: Adsorption part 6:Transport mechanism 62: Swivel arm 7: Wafer holding device 72: Holding part 722: Claw part 722a: Recess 74: Center positioning 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 8a: Central suction area 8b: Peripheral suction area 8c: Circular partition 8d: Outer frame 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 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 a transport mechanism for transporting the wafer and placing it on the chuck table, the transfer mechanism comprises a base having a central axis, and center positioning means disposed on the base for clamping the outer periphery of the wafer and aligning the center of the wafer with the central axis; the centering means comprises at least three clamping sections for clamping the outer periphery of the wafer, guide sections for guiding the movement of the clamping sections radially from the central axis of the base, a motor for moving the clamping sections, a load detection section for detecting the load of the motor, and a control section for controlling the clamping force for clamping the wafer so that the load detected by the load detection section becomes a predetermined value; the outer periphery of the wafer is clamped by the clamping portion so that the center axis of the base coincides with the center of the wafer, and the center axis of the base coincides with the rotation axis of the chuck table, and the wafer is placed on the clamping portion; The control unit detects the outer diameter of the wafer based on the amount of rotation of the motor, and operates the advancing / retracting means to position the cutting blade at a desired position from the outer periphery of the wafer placed on the chuck table.

2. 2. The processing apparatus according to claim 1, wherein the center positioning means includes a single motor whose rotation shaft is aligned with the central axis of the base, and an arm connected from the rotation shaft of the motor to each of the clamping portions.

Images