Wafer processing device

Abstract

To provide a wafer processing device capable of completely removing a chamfering part from a wafer outer periphery.SOLUTION: A wafer processing device includes: imaging means 7 to image a wafer 10 held by a chuck table 35 to detect an area to be irradiated with a laser beam; feeding means for processing 4 to feed for processing the chuck table in an X-axis direction and a Y-axis direction; rotary drive means to rotate the chuck table; and control means 100. The control means includes: a polar coordinate generator 110 positioning the imaging means on a wafer outer periphery and activating the rotary drive means to rotate the chuck table, and, with the center of rotation of the chuck table as the axis, generating the polar coordinates of the wafer outer periphery to store the polar coordinates; and a processing controller 120 controlling the feeding means for processing and the rotary drive means based on the polar coordinates, of the wafer outer periphery, having been generated by the polar coordinate generator and also radiating a laser beam by laser beam irradiation means 6 to perform laser processing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wafer processing apparatus for processing a wafer. [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 the desired thickness, and then the wafer is divided into individual device chips by a dicing machine, which are then used in electrical devices such as mobile phones and personal computers.

[0003] Furthermore, a chamfer is formed on the outer periphery of the wafer, and when the back surface of the wafer is ground to thin it, the chamfer becomes as sharp as a knife edge, which can injure an operator or cause cracks to form from the outer periphery of the wafer to the inside, damaging the device.

[0004] The above-mentioned problem is not limited to a single wafer, but can also occur in a bonded wafer formed by bonding together wafers on which patterns are formed by a surface activation method or the like.

[0005] Therefore, the present applicant has proposed a technology in which, before grinding the back surface of the wafer, a laser beam having a wavelength that is transparent to the wafer is focused on the inside of the chamfer formed on the outer periphery of the wafer and irradiated, forming a ring-shaped modified layer inside the wafer and removing the chamfer (see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-88187 Summary of the Invention [Problem to be solved by the invention]

[0007] However, even if the chamfered portion is removed by the technique described in Patent Document 1, the chamfered portion may not be completely removed from the outer periphery of the wafer, and a small amount may remain. This may cause problems such as the remaining portion falling off in a later process and becoming a source of contamination, or causing chipping of the device chips when the wafer is divided into individual device chips.

[0008] Furthermore, conventionally, voids (air gaps) of about 1 to 3 mm may occur on the outer periphery of the bonding surface of a bonded wafer, and in the region where the voids are formed, the wafer cannot be properly divided into individual device chips by laser processing or cutting processing.Furthermore, when the back surface of one of the wafers is ground to thin it, the wafer may be damaged.

[0009] Furthermore, when it is necessary to irradiate the laser beam while avoiding a notch in the wafer, or when it is necessary to make the area to be irradiated with the laser beam a slightly distorted ring shape due to the crystal structure of the wafer, there is a problem in that it is difficult to appropriately control the area to be irradiated with the laser beam accordingly.

[0010] The present invention has been made in view of the above-mentioned circumstances, and its main technical object is to provide a wafer processing apparatus that can solve the problems that occur when it is not possible to completely remove the chamfered portion from the outer periphery of the wafer, and that the remaining portion falls off in a later process and becomes a source of contamination, or that the device chips are chipped when the wafer is divided into individual device chips. [Means for solving the problem]

[0011] In order to solve the above-mentioned main technical problem, according to the present invention, there is provided a wafer processing apparatus for processing a wafer, comprising: a chuck table for holding a wafer; laser beam application means for applying a laser beam having a wavelength that is transparent to the wafer held on the chuck table; imaging means for imaging the wafer held on the chuck table and detecting an area to be irradiated with the laser beam; processing feed means for feeding the chuck table in the X-axis and Y-axis directions for processing; rotation drive means for rotating the chuck table; and control means, wherein the control means includes a polar coordinate generation unit that positions the imaging means at the outer periphery of the wafer and activates the rotation drive means to rotate the chuck table and generate and store polar coordinates of the outer periphery of the wafer around the center of rotation of the chuck table as an axis; and a processing control unit that controls the processing feed means and the rotation drive means based on the polar coordinates of the outer periphery of the wafer generated by the polar coordinate generation unit, and performs laser processing by applying a laser beam using the laser beam application means.

[0012] It is preferable that the polar coordinate generating unit stores the polar coordinates of a notch formed on the outer periphery of the wafer, which indicates the crystal orientation, and the processing control unit positions the laser beam inside the notch. It is also preferable that the control means includes a wafer polar coordinate storage unit that stores the polar coordinates of the area to be irradiated with the laser beam, with the center of the wafer as the axis, and the processing control unit combines the polar coordinates stored in the polar coordinate generating unit and the polar coordinates stored in the wafer polar coordinate storage unit to irradiate the wafer with the laser beam. [Effects of the Invention]

[0013] The wafer processing apparatus of the present invention comprises a chuck table for holding a wafer, laser beam application means for applying a laser beam having a wavelength that is transparent to the wafer held on the chuck table, imaging means for imaging the wafer held on the chuck table and detecting an area to be irradiated with the laser beam, processing feed means for processing the chuck table in the X-axis and Y-axis directions, rotation drive means for rotating the chuck table, and control means. The control means includes a polar coordinate generation unit that positions the imaging means at the outer periphery of the wafer and activates the rotation drive means to rotate the chuck table and generate and store polar coordinates of the outer periphery of the wafer around the center of rotation of the chuck table as an axis, and a processing control unit that controls the processing feed means and the rotation drive means based on the polar coordinates of the outer periphery of the wafer generated by the polar coordinate generation unit and performs laser processing by irradiating a laser beam using the laser beam application means. Therefore, the area to be irradiated with the laser beam can be appropriately adjusted to perform appropriate processing. As a result, the chamfered portion can be properly, i.e., completely, removed from the outer periphery of the wafer, thereby eliminating problems such as the remaining portion falling off and becoming a source of contamination in subsequent processes, or causing chipping of device chips when the wafer is divided into individual device chips. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an overall perspective view of a wafer processing device according to an embodiment of the present invention; [Figure 2] 2 is a perspective view showing a manner in which a wafer is placed on a chuck table of the processing apparatus shown in FIG. 1. FIG. [Figure 3] FIG. 10 is a perspective view showing an aspect in which the outer periphery of the wafer is imaged by a polar coordinate generating unit. [Figure 4] 10 is a conceptual diagram showing the polar coordinates of the outer periphery of the wafer and the polar coordinates for processing generated by the polar coordinate generating unit. FIG. [Figure 5] FIG. 1A is a perspective view showing an embodiment in which laser processing is performed on a wafer by a processing control unit, and FIG. 1B is a partially enlarged cross-sectional view of the embodiment of laser processing shown in FIG. [Figure 6] FIG. 10 is a conceptual diagram of polar coordinates stored in a wafer polar coordinate storage unit. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a wafer processing apparatus constructed based on the present invention will be described in detail with reference to the accompanying drawings.

[0016] 1 shows an overall perspective view of a wafer processing apparatus 1 configured based on the present invention. The processing apparatus 1 shown in the figure includes a chuck table 35 that holds a wafer 10, which is a workpiece, a laser beam application means 6 that applies a laser beam having a wavelength that is transparent to the wafer 10 held on the chuck table 35, an imaging means 7 that images the wafer 10 held on the chuck table 35 and detects an area to be irradiated with the laser beam, a processing feed means 4 that feeds the chuck table 35 in the X-axis and Y-axis directions for processing, a rotation drive means (not shown) that rotates the chuck table 35, and a control means 100.

[0017] FIG. 2 shows a wafer 10 to be processed by the wafer processing apparatus 1 of this embodiment. The wafer 10 is a bonded wafer formed by bonding a first wafer 10A and a second wafer 10B together. The first wafer 10A is, for example, a silicon wafer having a diameter of 300 mm and a thickness of 700 μm, and is a silicon wafer having a plurality of devices (not shown) formed on its surface. The first wafer 10A includes a device region near the center where devices to be used as products are formed, a chamfered portion 10Ac formed at the edge of the periphery surrounding the device region and having a width of, for example, 1 mm, and a peripheral excess region between the effective region and the chamfered portion 10Ac where no devices to be used as products are formed, having a width of, for example, 2 mm. Furthermore, a notch N, which is a notch indicating crystal orientation, is formed on the periphery of the first wafer 10A. The second wafer 10B also has a configuration similar to that of the first wafer 10A, and although not shown, is a silicon wafer having a plurality of devices formed on its surface, a chamfered portion 10Bc formed on the outer periphery, and a notch N indicating the crystal orientation. The wafer 10 shown in Fig. 2 is a wafer in which the surface of the first wafer 10A and the surface of the second wafer 10B are bonded together using the notch N indicating the crystal orientation as a reference and integrated by, for example, siloxane bonding, and the back surface 10Ab of the first wafer 10A and the back surface 10Bc of the second wafer 10B are exposed on the front and back sides.

[0018] Returning to FIG. 1 , the processing apparatus 1 includes a holding means 3 including a chuck table 35. As shown in FIG. 1 , the holding means 3 includes a rectangular X-axis direction movable plate 31 mounted on the base 2 so as to be movable in the X-axis direction; a rectangular Y-axis direction movable plate 32 mounted on the X-axis direction movable plate 31 so as to be movable in the Y-axis direction perpendicular to the X-axis direction; a cylindrical support 33 fixed to the upper surface of the Y-axis direction movable plate 32; and a rectangular cover plate 34 fixed to the upper end of the support 33. The cover plate 34 is provided with a chuck table 35 extending upward through an elongated hole formed in the cover plate 34. The chuck table 35 is rotatable by a rotation drive means (not shown) housed within the support 33. The chuck table 35 is provided with a circular suction chuck 35a formed of a breathable porous material and extending substantially horizontally. The suction chuck 35a is connected to a suction means (not shown) via a flow path passing through the support 33.

[0019] The processing feed means 4 includes an X-axis feed means 41 and a Y-axis feed means 44. The X-axis feed means 41 converts the rotational motion of a motor 42 into linear motion via a ball screw 43 and transmits the linear motion to the X-axis movable plate 31, moving the X-axis movable plate 31 back and forth in the X-axis direction along a pair of guide rails 2a, 2a arranged on the base 2 along the X-axis direction. The Y-axis feed means 44 converts the rotational motion of a motor 45 into linear motion via a ball screw 46 and transmits the linear motion to the Y-axis movable plate 32, moving the Y-axis movable plate 32 back and forth in the Y-axis direction along a pair of guide rails 31a, 31a arranged on the X-axis movable plate 31 along the Y-axis direction. A frame 5 is disposed on the base 2 to the side of the processing feed means 4, and is composed of a vertical wall 5a and a horizontal wall 5b extending horizontally from the upper end of the vertical wall 5a.

[0020] The horizontal wall 5b of the frame 5 accommodates an optical system constituting the laser beam application means 6 and an imaging means 7. A condenser 61 that constitutes part of the laser beam application means 6 and irradiates the wafer 10 with a laser beam is disposed on the underside of the tip of the horizontal wall 5b. The imaging means 7 is a means for capturing an image of the wafer 10 held on the chuck table 35 and detecting the position to be irradiated with the laser beam, and is disposed adjacent to the condenser 61 in the X-axis direction indicated by the arrow X in the figure.

[0021] 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., an input interface, and an output interface (details not shown).

[0022] The control means 100 is configured to include a polar coordinate generation unit 110 that generates and stores polar coordinates of the outer periphery of the wafer 10, with the center of rotation of the chuck table 35 as the axis, and a processing control unit 120 that controls the processing feed means 4 and the rotation means using the polar coordinates generated by the polar coordinate generation unit 110 to irradiate the laser beam.

[0023] The polar coordinate generating unit 110 and the machining control unit 120 are stored as control programs in the control means 100, and the control by the polar coordinate generating unit 110 and the machining control unit 120 is performed in the following procedure.

[0024] The wafers 10 loaded into the processing apparatus 1 of this embodiment are transferred to the chuck table 35 by a transfer means (not shown), and are placed on the suction chuck 35a of the chuck table 35 with the back surface 10Bb of the second wafer 10B facing downward and the back surface 10Ab of the first wafer 10A facing upward, as shown in Fig. 2. Next, a suction means (not shown) is activated to generate negative pressure in the suction chuck 35a, thereby suction-holding the wafer 10. At this time, the wafer 10 is transferred and placed so that the center O1 of the chuck table 35 and the center O2 of the wafer 10 coincide with each other, but perfect coincidence is difficult, and slight misalignment occurs.

[0025] Therefore, the polar coordinate generating unit 110 of the control unit 100 operates the processing feed unit 4 (X-axis feed unit 41 and Y-axis feed unit 44) to position the imaging unit 7 on the outer periphery of the first wafer 10A constituting the wafer 10 held on the chuck table 35, as shown in FIG. 3 . Next, the chuck table 35 is rotated in the direction indicated by arrow R1, and the imaging unit 7 captures an image of the outer periphery of the wafer 10. As shown in the figure, an angle sensor 330 that detects the rotation angle of the chuck table 35 is disposed on the rotation shaft 35b that supports the chuck table 35. The angle sensor 330 is, for example, a rotary encoder and is composed of a rotating disk 331 and a sensor unit 332 that receives light that passes through a slit in the rotating disk 331. This allows the control unit 100 to precisely detect the rotation angle of the chuck table 35 from the reference position.

[0026] The polar coordinate generating unit 110 detects the distance r from the rotation center O1 of the chuck table 35 to the outer periphery of the wafer 10, with the rotation center O1 of the chuck table 35 as the axis, by rotating the chuck table 35 as described above and using the imaging means 7 to capture an image of the outer periphery of the wafer 10 and performing image processing. Next, the polar coordinate generating unit 110 generates and stores polar coordinates (r, θ) of the outer periphery of the wafer 10 together with the rotation angle θ relative to the predetermined direction detected by the angle sensor 330. In FIG. 4, the polar coordinate P1 indicating the outer periphery of the wafer 10 generated in this manner is shown by a solid line. When detecting the polar coordinate P1 indicating the outer periphery of the wafer 10 in this manner, the notch N is also detected as part of the outer periphery of the wafer 10, and the polar coordinate generating unit 110 also stores the polar coordinates of the notch N (the distance from the rotation center O1 of the chuck table 35 and the rotation angle). In the illustrated embodiment, the notch N is detected at a rotation angle of 135°. 4, in this embodiment, the center O1 of rotation of the chuck table 35 is misaligned with the center O2 of the wafer 10, and therefore the polar coordinate P1 describes a curve as shown in the figure. If the center O1 of rotation of the chuck table 35 and the center O2 of the wafer 10 were perfectly aligned, r would be constant at r=150 mm, and the polar coordinate generating unit 110 would generate a linear polar coordinate indicated by the dashed line P0 in FIG.

[0027] As shown in FIG. 5(a), the processing control unit 120 provided in the control means 100 irradiates the peripheral excess region adjacent to the chamfered portion 10Ac with a laser beam LB having a wavelength that is transparent to the first wafer 10A. More specifically, for example, when the position to be irradiated with the laser beam LB is set 1.5 mm inside from the outer peripheral edge of the wafer 10, i.e., when set to a position 148.5 mm from the center O2 of the wafer 10, the processing polar coordinate Q1 (r-1.5 mm, θ) indicated by the dashed-dotted line is generated based on the polar coordinate P1 (r, θ) described above. The processing polar coordinate Q1 generated at this time is set to the peripheral excess region inside the wafer 10 that does not contact the notch N, based on the polar coordinate of the notch N stored in the polar coordinate generation unit 110.

[0028] The processing control unit 120 positions the focal point of the laser beam LB at a predetermined depth from the back surface 10Ab of the first wafer 10A, and based on the processing polar coordinate Q1 generated by the polar coordinate P1, operates the processing feed means 4 and the rotation drive means to rotate the chuck table 35 in the direction indicated by arrow R1 and feed it for processing, irradiating the laser beam LB to a position 0.5 mm inside the outer periphery of the first wafer 10A and forming a ring-shaped modified layer S along the outer periphery.

[0029] The processing conditions when carrying out the above laser processing are, for example, as shown below. Wavelength: 1342nm Repetition frequency: 60kHz Average power: 2.4W Chuck table rotation speed: 107.3 deg / sec

[0030] Furthermore, when irradiating the laser beam LB to remove the chamfered portion 10Ac formed on the outer periphery of the first wafer 10A as described above, for example, as shown in FIG. 5(b), the laser beam LB may be irradiated at multiple (e.g., eight) focal points positioned inside the first wafer 10A at an angle in the Y-axis direction to form a modified layer S. In this embodiment, the spacing between the focal points in the Y-axis direction is set to 10 μm based on the polar coordinate Q1, and the spacing between the focal points in the Z-axis direction (vertical direction) is set to 1 to 10 μm. Furthermore, when irradiating the laser beam LB in this manner, it is preferable to irradiate the same position with the laser beam LB twice.

[0031] After the ring-shaped modified layer S is formed inside the first wafer 10A along the outer periphery of the first wafer 10A as described above, the wafer 10 is transferred to a grinding device (not shown), and the back surface 10Ab of the first wafer 10A is ground by a predetermined amount. As a result, the first wafer 10A is thinned to a desired thickness, and an external force is applied to the first wafer 10A, causing cracks originating from the modified layer S to extend and removing the chamfered portion 10Ac of the first wafer 10A.

[0032] According to the above-described embodiment, by providing the polar coordinate generating unit 110 and the processing control unit 120, even if the rotation center O1 of the chuck table 35 is misaligned with the center O2 of the wafer 10 held on the chuck table 35, the area to be irradiated with the laser beam LB can be appropriately adjusted to perform proper processing. As a result, the chamfered portion 10Ac can be properly, i.e., completely, removed from the outer periphery of the wafer 10. This eliminates problems such as the remaining portion falling off in a later process and becoming a source of contamination, or causing chipping of device chips when the wafer 10 is divided into individual device chips.

[0033] The present invention is not limited to the above-described embodiment. As described above, the polar coordinates P1 of the outer periphery of the wafer 10 are generated and stored by the polar coordinate generating unit 110, and the polar coordinates of the notch N indicating the crystal orientation of the first wafer 10A are also stored. Then, based on the polar coordinates of the notch N generated by the polar coordinates P1, the processing control unit 120 may correct the processing polar coordinates Q1 to be set more inward in the region where the notch N is formed so that the laser beam LB is irradiated with a sufficient distance from the notch N in the region where the notch N is formed. By performing the laser processing described with reference to FIG. 5 based on the processing polar coordinates generated by such correction, the laser beam LB can be irradiated to an appropriate region avoiding the notch N, and the chamfered portion 10Ac can be more appropriately removed from the outer periphery of the wafer 10.

[0034] In addition to the above-described configuration, the control means 100 of this embodiment includes a wafer polar coordinate storage unit 130 that stores the polar coordinates of the area to be irradiated with the laser beam LB, with the center O2 of the wafer 10 as its axis. When performing the laser processing described with reference to FIG. 5 to form the modified layer S and remove the chamfered portion 10Ac, the characteristics of the chamfered portion 10Ac when it is separated and removed from the device region may vary depending on the rotation angle of the wafer 10 due to the influence of crystal orientation. Therefore, the position where the laser beam LB is irradiated to form the modified layer S may be set to a slightly distorted ring shape depending on the rotation angle, taking into account the crystal orientation. The wafer polar coordinate storage unit 130 of this embodiment stores the polar coordinate Q2 of the area to be irradiated with the laser beam LB, with the center O2 of the wafer 10 as its axis, taking into account the crystal orientation, as shown in FIG. 6. The polar coordinate Q2 is the polar coordinate of the position where the laser beam LB is irradiated to form the modified layer S, taking into account the crystal orientation, and forms a slightly distorted ring shape rather than a perfect ring shape.

[0035] When the above-described polar coordinate Q2 is stored in the wafer polar coordinate storage unit 130, the processing control unit 120 can generate new processing polar coordinates by combining the processing polar coordinate Q1 generated and stored by the polar coordinate generation unit 110 with the above-described polar coordinate Q2. The resulting polar coordinates are polar coordinates that correct the misalignment between the rotation center O1 of the chuck table 35 and the center O2 of the wafer 10, as shown in FIG. 4, and are also corrected by the polar coordinate Q2 (distance from the outer periphery r = 150 mm) set according to the rotation angle in consideration of the crystal orientation, as shown in FIG. 6. By performing laser processing based on these polar coordinates to form a modified layer S, even if the rotation center O1 of the chuck table 35 is misaligned from the center O2 of the wafer 10 held on the chuck table 35, the area to be irradiated with the laser beam LB can be appropriately adjusted to perform appropriate processing, and the modified layer S can be formed at a position that takes into consideration the influence of the crystal orientation.

[0036] Furthermore, when the imaging means 7 is composed of an infrared irradiation means and an infrared camera, when the outer periphery of the wafer 10 is imaged by the polar coordinate generation unit 110, it is possible to detect whether or not a void (a gap of 1 to 3 mm) exists on the outer periphery of the bonding surface between the first wafer 10A and the second wafer 10B. If such a void is detected, the polar coordinate generation unit 110 can generate a processing polar coordinate Q1 in an area avoiding the void. Note that, in order to irradiate the laser beam LB so as to avoid the void, before the wafer 10 is loaded into the processing apparatus 1, an image of the outer periphery of the unprocessed wafer 10 can be captured in advance by the infrared camera to detect whether or not a void exists on the outer periphery of the bonding surface of the wafer 10. If such a void is detected, polar coordinates are generated with the center O2 of the wafer 10 as the axis, and the polar coordinates are stored for each wafer 10 in the wafer polar coordinate storage unit 130. In this case, just as in the case where the polar coordinate Q2 is generated taking into consideration the crystal orientation described above, the processing polar coordinate Q1 stored in the polar coordinate generation unit 110 can be combined with the polar coordinates set to avoid voids stored in the wafer polar coordinate storage unit 130, and the laser beam LB can be irradiated onto the wafer 10.

[0037] As described above, by generating processing polar coordinates that avoid voids, it is possible to remove the chamfered portion 10Ac and also the area where the voids exist, thereby eliminating the problem of damaging the wafer during grinding.

[0038] In the above embodiment, an example is shown in which laser processing is performed on a wafer 10 formed by bonding a first wafer 10A and a second wafer 10B together, but the processing apparatus 1 of the present invention can also be applied to the case in which laser processing is performed on a single wafer, and the same effect as above can be achieved, that is, even if the rotation center O1 of the chuck table 35 and the center O2 of the wafer held on the chuck table 35 are misaligned, the area to be irradiated with the laser beam LB can be appropriately adjusted to perform appropriate processing, making it possible to properly remove the chamfered portion from the outer periphery of the wafer. [Explanation of symbols]

[0039] 1: Processing equipment 2: Base 3: Holding means 31:X-axis movable plate 32: Y-axis direction movable plate 33: Post 34: Cover plate 35: Chuck table 35a: Suction chuck 4: Processing feed means 41: X-axis feed means 42: Motor 43: Ball screw 44: Y-axis feed means 45: Motor 46: Ball screw 5:Frame body 5a: Vertical wall 5b:Horizontal wall part 6: Laser beam irradiation means 61: Concentrator 7: Imaging means 10: Wafer 10A: First wafer 10B: Second wafer 100: Control means 110: Polar coordinate generator 120: Processing control unit 130: Wafer polar coordinate storage unit S: Modified layer

Claims

1. A wafer processing device for processing a wafer, a chuck table for holding a wafer; laser beam application means for applying a laser beam having a wavelength that is transparent to the wafer held on the chuck table; imaging means for imaging the wafer held on the chuck table and detecting an area to be irradiated with the laser beam; processing feed means for processing feed of the chuck table in the X-axis direction and the Y-axis direction; rotation drive means for rotating the chuck table; and control means, The control means is a wafer processing device comprising: a polar coordinate generation unit that positions the imaging means at the outer periphery of the wafer and operates the rotation drive means to rotate the chuck table and generate and store polar coordinates of the outer periphery of the wafer around the center of rotation of the chuck table as an axis; and a processing control unit that controls the processing feed means and the rotation drive means based on the polar coordinates of the outer periphery of the wafer generated by the polar coordinate generation unit and performs laser processing by irradiating a laser beam using laser beam application means.

2. 2. The wafer processing device according to claim 1, wherein the polar coordinate generating unit stores the polar coordinates of a notch formed on the outer periphery of the wafer, the notch indicating the crystal orientation, and the processing control unit positions the laser beam inside the notch.

3. the control means includes a wafer polar coordinate storage unit for storing polar coordinates of an area to be irradiated with the laser beam, with the center of the wafer as an axis; 3. The wafer processing device according to claim 1, wherein the processing control unit synthesizes the polar coordinates stored in the polar coordinate generation unit and the polar coordinates stored in the wafer polar coordinate storage unit and irradiates the wafer with a laser beam.

Images