Bevelling device

Abstract

To provide a bevelling device capable of easily achieving an adaptive bevelling of a wafer.SOLUTION: A bevelling device comprises: a laser beam irradiation unit that irradiates a workpiece with a laser beam for processing; a position detection device that is used when detecting a position of an outer peripheral edge of the workpiece; and a controller. The laser beam irradiation unit includes: a laser oscillator that generates the laser beam by laser oscillation; a light focus lens that focuses the laser beam to guide it to the workpiece; and a deflector that is arranged between the laser oscillator and the light focus lens and changes an irradiation position on the workpiece to which the laser beam is irradiated by changing a position where the laser beam is entered into a capacitor lens by deflecting the laser beam. The controller calculates a position of the outer peripheral edge of the workpiece by using information obtained by the position detection device and operates the deflector so that the irradiation position of the laser beam is deviated along the outer peripheral edge.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a chamfering device. [Background technology]

[0002] Disk-shaped wafers made of semiconductor materials such as silicon are used to manufacture device chips to be incorporated into various electronic devices. These wafers are obtained, for example, by subjecting as-sliced ​​wafers, which are obtained by slicing a cylindrical ingot with a wire saw or the like, to a lapping process for increasing the flatness of the front and back surfaces, and a chamfering process for removing corners remaining on the outer periphery.

[0003] A known example of a processing method related to the above-mentioned chamfering is described in Patent Document 1. In the processing method of Patent Document 1, a disk-shaped processing tool having a ring-shaped grinding wheel for chamfering on its outer periphery and a wafer are both rotated, and the outer periphery of the processing tool (grinding wheel) is pressed against the outer periphery of the wafer from the side, thereby chamfering the wafer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-347901 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when chamfering is performed using the annular grinding wheel described in Patent Document 1, if the center of rotation of the wafer is misaligned with the center of the wafer, the entire circumference of the wafer's outer periphery will not be ground evenly by the grinding wheel, which will result in a low circularity of the wafer after chamfering.

[0006] In addition, the grinding wheel used in the chamfering process wears as the chamfering process progresses, so in order to obtain a wafer with a desired diameter, the position of the processing tool relative to the wafer must be adjusted according to the degree of wear of the grinding wheel. However, such adjustments are performed manually based on the experience of the operator, so a skilled operator is required to achieve appropriate chamfering of the wafer.

[0007] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a chamfering apparatus capable of easily realizing appropriate chamfering of a workpiece such as a wafer. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a chamfering apparatus for chamfering a workpiece, the chamfering apparatus comprising: a holding unit for holding the workpiece; a laser beam irradiating unit for irradiating the workpiece held by the holding unit with a laser beam for processing; a position detector for use in detecting the position of the outer periphery of the workpiece; a processing device; and a storage device. The processing device and the storage device further comprise a controller for controlling the operations of the holding unit, the laser beam irradiating unit and the position detector in accordance with a program stored in the storage device. The laser beam irradiating unit generates the laser beam by laser oscillation. a focusing lens that focuses the laser beam and guides it to the workpiece; and a deflector that is disposed between the laser oscillator and the focusing lens and deflects the laser beam to displace the position at which the laser beam is incident on the focusing lens, thereby displacing an irradiation position on the workpiece to be irradiated with the laser beam, wherein the controller calculates the position of the outer periphery of the workpiece using information obtained by the position detector in accordance with the program, and operates the deflector to displace the irradiation position of the laser beam along the outer periphery.

[0009] Preferably, the machine further comprises a shape measuring device used for measuring the shape of the outer periphery including the outer periphery of the workpiece.

[0010] Preferably, the memory device stores information regarding the target shape of the outer periphery of the workpiece after processing, and the controller, in accordance with the program, compares the shape of the outer periphery indicated by the information obtained by the shape measuring device with the information regarding the target shape to determine whether the workpiece has been appropriately chamfered.

[0011] Preferably, the controller operates the laser beam irradiation unit in accordance with the program so as to change the conditions of the laser beam irradiated to the workpiece based on the results obtained by comparing the shape of the outer periphery indicated by the information obtained by the shape measuring device with the information regarding the target shape.

[0012] Preferably, the controller operates the laser beam application unit in accordance with the program so that a mark is formed by the laser beam in an area inside the outer periphery of the workpiece based on the position of the outer periphery. Effect of the Invention

[0013] The chamfering device according to one aspect of the present invention calculates the position of the outer periphery of the workpiece using information obtained by a position detector, and performs chamfering by operating a deflector to displace the irradiation position of the laser beam along the outer periphery. Therefore, it is not necessary for an operator to manually adjust the position of the center of rotation of the wafer relative to the center of the wafer, or the position of the processing tool relative to the wafer. Therefore, the chamfering device according to one aspect of the present invention can easily achieve appropriate chamfering of the wafer. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram of a chamfering device according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing a functional configuration of a processing device realized by a program. [Diagram 3] FIG. 3 is a flow diagram of the chamfering method according to the first embodiment. [Figure 4] FIG. 4 is a top view of the suction member and the workpiece. [Diagram 5] FIG. 5 is a top view of the suction member and the workpiece. [Figure 6] FIG. 6 is a schematic diagram showing an example of processing of an image of the outer periphery measured by a position detector. [Figure 7] FIG. 7 is a side view of a portion of a workpiece and a laser beam when performing a chamfering step. [Figure 8] FIG. 7 is a side view of a portion of a workpiece and a laser beam when performing a chamfering step. [Figure 9] FIG. 7 is a side view of a portion of a workpiece and a laser beam when performing a chamfering step. [Figure 10] FIG. 7 is a side view of a portion of a workpiece and a laser beam when performing a chamfering step. [Figure 11] FIG. 11 is a graph showing an example of the shape (shape equivalent to a cross section along the radial direction) of the outer periphery of a workpiece measured using a shape measuring device. [Figure 12] FIG. 12 is a side view showing a part of a first example of a workpiece 11 that has been chamfered. [Figure 13] FIG. 13 is a side view showing a part of a second example of a workpiece 11 that has been chamfered. [Figure 14] FIG. 14 is a flow diagram of the chamfering method according to the second embodiment. [Figure 15] FIG. 15 is a schematic diagram of a chamfering device according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [First embodiment] Hereinafter, a chamfering device and a chamfering method according to a first embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view of a chamfering device 2 according to the first embodiment. In Fig. 1, some of the elements constituting the chamfering device 2 are expressed by functional blocks. In addition, the X-axis (first axis), Y-axis (second axis), and Z-axis (third axis) used in the following description are perpendicular to each other.

[0016] As shown in Fig. 1, the chamfering device 2 includes a holding unit 4 for holding a workpiece 11. Here, the workpiece 11 is, for example, a disk-shaped wafer made of a semiconductor material such as silicon. That is, as shown in Fig. 1, the workpiece 11 is configured in a substantially disk shape having a substantially circular first surface 11a and a substantially circular second surface 11b opposite to the first surface 11a. An orientation flat 11c is formed on a part of the outer periphery of the workpiece 11 to indicate the crystal orientation of the workpiece 11.

[0017] The diameter of the workpiece 11 (the width of the first surface 11a or the second surface 11b) is, for example, 100 mm to 300 mm, typically 150 mm. The thickness of the workpiece 11 is, for example, 0.3 mm to 1 mm, typically 0.7 mm. The material, shape, diameter (the width of the first surface 11a or the second surface 11b), and thickness of the workpiece 11 are not limited to these. Also, the workpiece 11 may have a notch instead of the orientation flat 11c. Furthermore, the workpiece 11 may not have an orientation flat 11c or a notch.

[0018] 1, the holding unit 4 has an adsorption member (adsorption pad) 6 having an adsorption surface (not shown) at the bottom for adsorbing the first surface 11a or the second surface 11b of the workpiece 11. The adsorption member 6 has a flow path (not shown) therein, one end of which opens to the adsorption surface. Meanwhile, the other end of the flow path is connected to a negative pressure source (not shown).

[0019] For example, when the suction surface of the suction member 6 is in contact with the first surface 11a or the second surface 11b of the workpiece 11 from above and negative pressure generated from a negative pressure source acts on the suction surface through a flow path, the workpiece 11 is sucked and held by the suction surface. In FIG. 1, the first surface 11a of the workpiece 11 is held from above. That is, the first surface 11a of the workpiece 11 is the held surface. Note that the second surface 11b of the workpiece 11 may also be held.

[0020] A rotation drive source 8 such as a motor (not shown) is connected to the attraction member 6. When the driving force of the rotation drive source 8 acts on the attraction member 6, the attraction member 6 rotates around a rotation axis 42 that is approximately parallel to the Z axis. In other words, the workpiece 11 held by the attraction member 6 also rotates around the rotation axis 42 that is approximately parallel to the Z axis.

[0021] The rotary drive source 8 is supported from above by a Z-axis movement mechanism 10. The Z-axis movement mechanism 10 is provided with a pair of guide rails (not shown) that are fixed to, for example, a housing of the chamfering device 2 and are long in a direction (vertical direction) generally parallel to the Z axis. A moving plate is attached to the pair of guide rails in such a manner that it can slide along the Z axis.

[0022] The movable plate is provided with a nut portion (not shown) that constitutes a ball screw, and a screw shaft (not shown) that is roughly parallel to the Z axis is rotatably connected to this nut portion. A motor or the like is connected to one end of the screw shaft. By rotating the screw shaft with a motor or the like, the movable plate moves up and down along the guide rail. A rotation drive source 8 is supported by this movable plate, and moves up and down together with the suction member 6 when the movable plate moves up and down.

[0023] A laser beam irradiation unit 12 is disposed above the holding unit 4, which can irradiate the workpiece 11 held by the holding unit 4 with a laser beam 38 for processing. The laser beam irradiation unit 12 includes a laser oscillator 14 that generates the laser beam 38 by laser oscillation. The laser oscillator 14 includes a laser medium such as Nd:YAG that is suitable for laser oscillation, and can generate, for example, a pulsed laser beam 38 of a wavelength that is absorbed by the workpiece 11, that is, a wavelength at which the workpiece 11 is appropriately ablated.

[0024] A deflector 18 such as an AOD (Acousto-Optic Deflector) or a galvanometer scanner is disposed downstream of the laser oscillator 14 along the traveling direction of the laser beam 38. The laser beam 38 generated by the laser oscillator 14 is deflected by the deflector 18, and the traveling direction of the laser beam 38 is changed to a downward direction (along the Z-axis).

[0025] Below the deflector 18, a condenser lens 16 such as an fθ lens capable of condensing the laser beam 38 to a further lower condensing point is disposed. The laser beam 38 deflected by the deflector 18 passes through the condenser lens 16 and is irradiated onto the outer periphery of the workpiece 11 held by the chucking member 6. In other words, the deflector 18 adjusts the traveling direction of the laser beam 38 so that the outer periphery of the workpiece 11 is appropriately irradiated with the laser beam 38.

[0026] The chamfering device 2 includes a position detector 22 used to detect the position of the outer periphery of the workpiece 11 held by the holding unit 4. The position detector 22 acquires an image of an area including the outer periphery of the workpiece 11. Specifically, for example, a ring-shaped light source (not shown) surrounding the condenser lens 16 is disposed below the condenser lens 16 and above the holding unit 4. Light 40 emitted from this light source and reflected by the outer periphery of the held surface side (first surface 11a side in FIG. 1) including the outer periphery of the workpiece 11 is further reflected by the mirror 20 and enters the position detector 22.

[0027] By disposing such a light source, it is possible to obtain an image in which the outer periphery of the workpiece 11 is clearly shown. As the light source, for example, a fluorescent lamp or an LED (Light Emitting Diode) capable of emitting white light in the visible range is used. However, in cases where light can be taken in from outside the chamfering device 2, the light source may be omitted.

[0028] As the mirror 20, for example, a dichroic mirror that transmits light of the same wavelength as the laser beam 38 and reflects light of other wavelengths is used. By using a mirror 20 with such properties, the outer periphery of the workpiece 11 is irradiated with the laser beam 38, and an image including the outer periphery of the workpiece 11 can be obtained.

[0029] The position detector 22 includes a light receiving element, such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor, that is sensitive to light in the visible range. Therefore, when light is incident on the position detector 22, the position detector 22 generates an electrical signal according to the intensity of the incident light.

[0030] The chamfering device 2 further includes a shape measuring device 24 used when measuring the shape of the outer periphery of the held surface side (first surface 11a side in FIG. 1) including the outer periphery of the workpiece 11 held by the above-mentioned holding unit 4. This shape measuring device 24 is disposed at a position obtained by rotating the position of the condenser lens 16 by 90° around the rotation axis 42, for example.

[0031] For example, a triangulation type measuring instrument using a laser beam is used as the shape measuring instrument 24. Specifically, the shape measuring instrument 24 includes, for example, a light emitting unit (not shown) that emits a wide laser beam 44 having a predetermined width, and a light receiving unit (not shown) that receives the laser beam 44 reflected by the workpiece 11.

[0032] The light emitting unit of this embodiment emits a long linear laser beam 44 toward the outer periphery of the workpiece 11 in a direction intersecting the outer periphery of the workpiece 11 (the direction along the X-axis in FIG. 1). This allows the shape of the outer periphery of the workpiece 11 to be measured all at once in the linear irradiation range of the laser beam 44. The light receiving unit is composed of a light receiving element such as a two-dimensional CCD image sensor or a two-dimensional CMOS image sensor so as to appropriately receive the linear laser beam 44 reflected by the workpiece 11.

[0033] This shape measuring device 24 is configured, for example, so that the incident position of the laser beam 44, which is reflected at an arbitrary irradiated position (measurement point) on the held surface side of the workpiece 11 and enters the light receiving part (light receiving element), is displaced according to the distance between the irradiated position and the light emitting part. In other words, the shape measuring device 24 is configured so as to be able to measure the distance from the shape measuring device 24 to each measurement point of the workpiece 11.

[0034] Therefore, by utilizing the information output from the shape measuring device 24, it is possible to calculate the distance from the shape measuring device 24 to each measurement point on the outer periphery of the held surface side of the workpiece 11, that is, the shape of the outer periphery of the workpiece 11. The shape measuring device 24 may also be used to detect the position of the outer periphery of the workpiece 11. In other words, the shape measuring device 24 may also serve as the position detector 22.

[0035] A controller (control unit) 26 is connected to each element of the chamfering device 2, including the position detector 22 and the shape measuring device 24. This controller 26 is configured by a computer including, for example, a processing device 28 and a storage device 36, and controls the operation of each element of the chamfering device 2 described above so that the workpiece 11 is appropriately chamfered.

[0036] The processing device 28 is typically a CPU (Central Processing Unit) and performs various processes required to control the above-mentioned elements. The storage device 36 includes, for example, a main storage device such as a DRAM (Dynamic Random Access Memory) and an auxiliary storage device such as a hard disk drive or a flash memory. The functions of the controller 26 are realized, for example, by the processing device 28 operating in accordance with a program (software) stored in the storage device 36. However, the controller 26 may be realized only by hardware.

[0037] Fig. 2 is a block diagram showing the functional configuration of the processing device 28 realized by a program. As shown in Fig. 2, the processing device 28 includes an outer peripheral edge position detection unit 30, a shape measurement unit 32, and a processing control unit 34. The outer peripheral edge position detection unit 30 calculates the position of the outer peripheral edge of the workpiece 11 from an image of an area including the outer peripheral edge of the workpiece 11 acquired by the position detector 22. Specifically, for example, the brightness of all pixels constituting this image is binarized to obtain a binarized image, and the binarized image is subjected to processing such as edge detection to extract the coordinates of the outer peripheral edge of the workpiece 11.

[0038] Further, the shape measuring unit 32 calculates the shape of the peripheral portion of the workpiece 11 from the information acquired by the shape measuring device 24. Specifically, the shape measuring unit 32 acquires the shape of the outer periphery on the first surface 11a side of the workpiece 11 as a collection of each measurement point based on the distance from the shape measuring device 24 to each measurement point. The processing control unit 34 controls the irradiation conditions (processing conditions) of the laser beam 38 including the conditions of deflection of the laser beam 38 by the deflector 18 (scanning conditions of the laser beam 38) based on information provided from, for example, the outer periphery edge position detection unit 30 and the shape measuring unit 32.

[0039] Next, a chamfering method using the above-mentioned chamfering device will be described. Fig. 3 is a flow diagram of the chamfering method according to the first embodiment. As shown in Fig. 3, the chamfering method of this embodiment includes a holding step S1, an outer peripheral edge detection step S2, a chamfering step S3, a shape measurement step S4, and a determination step S5 for determining whether the workpiece 11 has been chamfered into a target shape. In this embodiment, each step constituting the chamfering method is performed based on a command from the controller 26.

[0040] In the holding step S1, the workpiece 11 is held by the holding unit 4. In this embodiment, in a state where the suction surface of the suction member 6 is in contact with the first surface 11a, which is the held surface of the workpiece 11, a negative pressure is applied from a negative pressure source, so that the first surface 11a of the workpiece 11 is sucked to the suction surface and held.

[0041] In the outer peripheral edge detection step S2, the position of the outer peripheral edge of the workpiece 11 held by the holding unit 4 is detected based on the image acquired by the position detector 22. Figures 4 and 5 are top views of the attraction member 6 and the workpiece 11. As shown in Figures 4 and 5, the positional relationship between the attraction member 6 and the imaging area 46 of the position detector 22 is adjusted in advance so that the imaging area 46 overlaps with the outer peripheral edge of the workpiece 11 when the workpiece 11 is appropriately held by the holding unit 4.

[0042] For example, light 40 emitted from the light source and reflected by the workpiece 11 is further reflected by the mirror 20 and enters the position detector 22. The light 40 that enters the position detector 22 is received by a light receiving element provided in the position detector 22, converted into an electrical signal, and transmitted to the controller 26 as image information.

[0043] Fig. 6 is a schematic diagram showing an example of processing of an image acquired by the position detector 22. For the image information transmitted to the controller 26, the outer periphery position detection unit 30, for example, binarizes the luminance of all pixels constituting the image to acquire a binary image as shown in Fig. 6, and performs processing such as edge detection on this binary image to extract the coordinates of the outer periphery of the workpiece 11.

[0044] In this embodiment, the position of the outer periphery of the workpiece 11 is detected over the entire circumference by rotating the workpiece 11 once by the rotary drive source 8 of the holding unit 4. This allows the position of the outer periphery of the workpiece 11, including the orientation flat 11c and notches, to be properly detected. Information on the position of the outer periphery of the workpiece 11 detected in this manner is stored in the storage device 36.

[0045] In the chamfering step S3, the outer periphery including the outer periphery of the workpiece 11 detected in the outer periphery detection step S2 is irradiated with the laser beam 38, thereby chamfering the workpiece 11. Specifically, in the outer periphery detection step S2, based on the information on the position of the outer periphery of the workpiece 11 acquired by the outer periphery position detection unit, the processing control unit 34 selects irradiation conditions including the irradiation position of the laser beam 38 so that the outer periphery of the workpiece 11 is chamfered into a desired shape.

[0046] 7, 8, 9, and 10 are side views showing a part of the workpiece 11 and the laser beam 38 when the chamfering step S3 is performed. An example of the chamfering method will be described below with reference to FIGS. 7, 8, 9, and 10. In addition, in FIGS. 7, 8, 9, and 10, Y max and Y min are the irradiation positions of the laser beam 38 set at the outermost and innermost positions along the radial direction of the workpiece 11, respectively, and Y max Y coincides with the position of the outer periphery (end) of the workpiece 11. min and Y max A laser beam 38 is irradiated onto the region between and .

[0047] First, as shown in FIG. 7, the irradiation position of the laser beam 38 is set to the outer periphery (Y max The position where the laser beam 38 enters the condenser lens 16 is adjusted by the deflector 18 so that it coincides with the position of the end of the workpiece 11 (Y max The laser beam 38 is irradiated onto the position Y max The workpiece 11 is ablated in an annular region corresponding to the position of the ablation, and a portion of the workpiece corresponding to this annular region is removed.

[0048] Next, as shown in Fig. 8, the position where the laser beam 38 enters the condenser lens 16 is adjusted by the deflector 18 so that the irradiation position of the laser beam 38 moves a predetermined distance toward the center of the workpiece 11 (in the direction of the arrow in Fig. 8). In this state, the holding unit 4 rotates one or more times, and the laser beam 38 is irradiated onto the entire circumference of the workpiece 11. As a result, Y max The workpiece 11 is further ablated in an annular region a predetermined distance inward from the annular region, and a portion of the workpiece corresponding to this annular region is further removed.

[0049] Then, the movement of the irradiation position of the laser beam 38 toward the center and the rotation of the workpiece 11 are repeated, and the annular regions of the workpiece 11 are processed in sequence. The movement of the irradiation position of the laser beam 38 toward the center and the rotation of the workpiece 11 are performed such that the irradiation position is min This is repeated until the position of the laser beam 38 of the first stage of irradiation of the workpiece 11 is reached.

[0050] Next, as shown in FIG. 9, the irradiation position of the laser beam 38 is again shifted to the end portion (Y max The position at which the laser beam 38 enters the condenser lens 16 is adjusted by the deflector 18 so that it coincides with the position (position (a) of the laser beam 38 entering the condenser lens 16). In this state, the holding unit 4 rotates one or more times, and the laser beam 38 is irradiated onto the entire circumference of the end of the top surface of the workpiece 11 that has been newly formed by the irradiation of the laser beam 38 in the first stage.

[0051] This means that Y max The workpiece 11 is further ablated in the annular region corresponding to the position of the workpiece 11, and a part of the workpiece corresponding to the annular region is further removed. Note that, at the timing when the second stage of irradiation with the laser beam 38 starts, the irradiation position of the laser beam 38 may be moved downward along the Z-axis direction.

[0052] For example, the workpiece 11 can be more appropriately processed by moving the irradiation position of the laser beam 38 along the Z-axis direction in accordance with the depth to which the workpiece 11 has been processed by the irradiation of the first-stage laser beam 38. Note that, in cases where the focal depth of the condenser lens 16 is sufficiently large and the energy density of the laser beam 38 at the irradiation position is sufficiently large, there is no need to move the irradiation position of the laser beam 38 along the Z-axis direction.

[0053] Next, as shown in Fig. 10, the position where the laser beam 38 enters the condenser lens 16 is adjusted by the deflector 18 so that the irradiation position of the laser beam 38 moves a predetermined distance toward the center of the workpiece 11 (in the direction of the arrow in Fig. 10). In this state, the holding unit 4 rotates one or more times, and the laser beam 38 is irradiated onto the entire circumference of the top surface of the workpiece 11 formed by the irradiation of the laser beam 38 in the first stage. As a result, Y max The workpiece 11 is further ablated in an annular region a predetermined distance inward from the annular region, and a portion of the workpiece corresponding to this annular region is further removed.

[0054] Then, the movement of the irradiation position of the laser beam 38 toward the center and the rotation of the workpiece 11 are repeated, and the annular regions of the workpiece 11 are processed in sequence. The movement of the irradiation position of the laser beam 38 toward the center and the rotation of the workpiece 11 are performed such that the irradiation position is min +α position (Y min This is repeated until the workpiece 11 reaches a position that is α toward the outer periphery side from the position indicated by the arrow A. In this manner, the second stage of irradiation of the laser beam 38 on the workpiece 11 is completed.

[0055] After that, the nth stage (n is an integer of 2 or more) of the laser beam 38 is irradiated in the same manner. In the nth stage of the laser beam 38 irradiation, the irradiation position is set to Y min This is repeated until the mth stage (m is Y min +mα>Y max When the irradiation of the laser beam 38 of the number of laser beams 38 (the smallest integer satisfying the above) is completed, the chamfering of the first surface 11a of the workpiece 11 is completed. After the chamfering of the first surface 11a of the workpiece 11 is completed, the chamfering of the second surface 11b of the workpiece 11 is also performed, if necessary.

[0056] When the workpiece 11 is SiC, the wavelength of the laser beam 38 is set to 266 nm or more and 1100 nm or less, typically 355 nm. The average power of the laser beam 38 is set to 0.2 W or more and 5 W or less, typically 1.5 W. The repetition frequency of the laser beam 38 is set to 30 kHz or more and 200 kHz or less, typically 80 kHz. The pulse width of the laser beam 38 is set to 1 ns or more and 300 ns or less, typically 5 ns. The peripheral speed of the workpiece 11 (the speed at which the processed area of ​​the workpiece 11 moves) is set to 30 mm / s or more and 1000 mm / s or less, typically 100 mm / s. In addition, the focal length of the focusing lens 16 is set to 90 mm or more and 300 mm or less, typically 100 mm, and the diameter (spot diameter) of the laser beam 38 on the workpiece 11 is set to 10 μm or more and 50 μm or less, typically 15 μm.

[0057] In the subsequent shape measurement step S4, the shape of the outer periphery of the workpiece 11 after the chamfering step S3 is acquired based on the information obtained by the shape measuring device 24. That is, the shape of the outer periphery of the workpiece 11 is measured. Then, in a determination step S5, it is determined whether or not the outer periphery of the workpiece 11 has been chamfered into a target shape (target shape).

[0058] Fig. 11 is a graph showing an example of the shape (shape corresponding to a cross section along the radial direction) of the outer periphery of the workpiece 11 measured using the shape measuring instrument 24. In Fig. 11, a solid line indicates the shape of a part of the outer periphery of the workpiece 11, and a dashed line indicates a target shape 48 that is the target of the chamfering. The processing device 28 compares the difference between the shape of the outer periphery of the workpiece 11 indicated by the information obtained by the shape measuring instrument 24 and the target shape 48 previously stored in the storage device 36.

[0059] Specifically, the processing device 28 compares the difference between the height (height difference of the chamfer) A of the chamfered portion of the workpiece 11, which is an inclined surface formed by chamfering and inclined relative to the first surface 11a, and the height (height difference of the target shape 48) A0 of the target shape 48, which is the targeted inclined surface. The processing device 28 also compares the width (length of the chamfered portion along the radial direction) B of the chamfered portion of the workpiece 11 with the width (length of the target shape 48 along the radial direction) B0 of the chamfered portion of the target shape 48. The processing device 28 determines whether these differences are within an allowable range.

[0060] When the processing device 28 determines that the difference exceeds the allowable range, the chamfering step S3 is executed again. At this time, it is preferable that the processing control unit 34 resets the irradiation conditions (processing conditions) of the laser beam 38 based on the difference between the shape of the workpiece 11 transmitted to the shape measuring unit 32 and the target shape 48 previously stored in the storage device 36. By executing the chamfering step S3 again using the thus reset processing conditions, the workpiece 11 can be chamfered more appropriately. Note that the outer periphery detection step S2 may be executed before executing the chamfering step S3 again.

[0061] On the other hand, if the processor 28 determines that the difference is within the allowable range, the chamfering method consisting of the series of steps described above is terminated.

[0062] FIG. 12 is a side view showing a part of a first example of the workpiece 11 that has been chamfered. The material of the workpiece 11 shown in FIG. 12 is SiC, and the thickness is 0.7 mm. The height of the chamfered portion of the workpiece 11 (height difference of the chamfered portion) a1 is 140 μm, and the width of the chamfered portion of the workpiece 11 (length of the chamfered portion along the radial direction) b1 is 210 μm. The wavelength of the laser beam 38 is set to 355 nm, the focal length of the laser beam 38 is set to 100 mm, the average output of the laser beam 38 is set to 1.5 W, the repetition frequency of the laser beam 38 is set to 80 kHz, and the pulse width of the laser beam 38 is set to 5 ns. The above-mentioned α (see FIG. 10) is set to 5 μm. In this first example, the peripheral speed of the workpiece 11 is set to 350 mm / s.

[0063] FIG. 13 is a side view showing a part of a second example of a workpiece 11 that has been chamfered. In this second example, the same workpiece 11 as in the first example is used. In this second example, the same machining conditions as in the first example are applied, except that the peripheral speed of the workpiece 11 is set to 100 mm / s. In FIG. 13, the height (height difference of the chamfer) a2 of the chamfered portion of the workpiece 11 is 330 μm, and the width (length of the chamfered portion along the radial direction) b2 of the chamfered portion of the workpiece 11 is 210 μm. As shown in FIG. 12 and FIG. 13, by changing the irradiation conditions of the laser beam 38, a chamfered portion of any shape can be formed.

[0064] In addition, in the chamfering step S3, the irradiation position of the laser beam 38 is set to Y min From the position of Y max In this case, first, the irradiation position of the laser beam 38 is moved to the Y min The deflector 18 adjusts the position where the laser beam 38 enters the condenser lens 16 so that it coincides with the position of Y. In this state, the holding unit 4 rotates one or more times, and the laser beam 38 is irradiated onto the entire circumference of the workpiece 11. minThe workpiece 11 is ablated in an annular region corresponding to the position of the ablation, and a portion of the workpiece corresponding to this annular region is removed.

[0065] Next, the position where the laser beam 38 enters the condenser lens 16 is adjusted by the deflector 18 so that the irradiation position of the laser beam 38 moves a predetermined distance toward the outer periphery of the workpiece 11. In this state, the holding unit 4 rotates one or more times, and the laser beam 38 is irradiated onto the entire circumference of the workpiece 11. As a result, Y max The workpiece 11 is further ablated in an annular region a predetermined distance from the outer circumferential edge, and a portion of the workpiece corresponding to this annular region is further removed.

[0066] Then, the movement of the irradiation position of the laser beam 38 toward the outer periphery side and the rotation of the workpiece 11 are repeated, and the annular region of the workpiece 11 is processed in sequence. The movement of the irradiation position of the laser beam 38 toward the outer periphery side and the rotation of the workpiece 11 are performed such that the irradiation position is max This is repeated until the position of the laser beam 38 of the first stage of irradiation of the workpiece 11 is reached.

[0067] Thereafter, the irradiation position of the laser beam 38 is shifted to Y min The position where the laser beam 38 enters the condenser lens 16 is adjusted by the deflector 18 so that it coincides with the position of +α. Then, in this state, the holding unit 4 rotates one or more times, and the laser beam 38 is irradiated to the entire circumference of the end of the top surface of the workpiece 11 that is newly formed by the irradiation of the laser beam 38 in the first stage. As a result, Y max The workpiece 11 is further ablated in an annular region corresponding to the position of the workpiece 11, and a portion of the workpiece corresponding to this annular region is further removed.

[0068] Next, the position where the laser beam 38 enters the condenser lens 16 is adjusted by the deflector 18 so that the irradiation position of the laser beam 38 moves a predetermined distance toward the outer periphery of the workpiece 11. In this state, the holding unit 4 rotates one or more times, and the laser beam 38 is irradiated onto the entire periphery of the upper surface of the workpiece 11 formed by the irradiation of the laser beam 38 in the first stage. As a result, Y min The workpiece 11 is further ablated in an annular region a predetermined distance from +α toward the outer circumferential edge, and a portion of the workpiece corresponding to this annular region is further removed.

[0069] Then, the movement of the irradiation position of the laser beam 38 toward the outer periphery side and the rotation of the workpiece 11 are repeated, and the annular region of the workpiece 11 is processed in sequence. The movement of the irradiation position of the laser beam 38 toward the outer periphery side and the rotation of the workpiece 11 are performed such that the irradiation position is moved in a direction parallel to the axis Y max This is repeated until the position of the laser beam 38 of the second stage of irradiation of the workpiece 11 is reached.

[0070] After that, the nth stage (n is an integer of 2 or more) of the laser beam 38 is irradiated in the same manner. In the nth stage of the laser beam 38 irradiation, the first irradiation position is Y min This is repeated until the mth stage (m is Y min +mα>Y max When the irradiation of the laser beam 38 of the number of laser beams 38 corresponding to the number of adjacent laser beams 38 that satisfies the above formula (the smallest integer that satisfies the above formula) is completed, the chamfering of the first surface 11a of the workpiece 11 is completed.

[0071] However, in this case, since the workpiece 11 is present on the periphery of the irradiation position of the laser beam 38, the shock wave caused by the irradiation of the laser beam 38 is unlikely to escape from the irradiation position. On the other hand, when the irradiation position of the laser beam 38 is moved from the outer periphery of the workpiece 11 to the center, since the workpiece 11 has already been removed on the outer periphery side of the irradiation position, the shock wave is likely to escape from the outer periphery side of the irradiation position to the outside of the workpiece 11, and damage such as cracks is unlikely to occur in the workpiece 11. Therefore, in the chamfering step S3, it can be said that it is more preferable to move the irradiation position of the laser beam 38 from the outer periphery side of the workpiece 11 to the center side.

[0072] [Second embodiment] Next, a description will be given of a chamfering device and a chamfering method according to a second embodiment. As the chamfering device of this embodiment, the same chamfering device as the chamfering device according to the first embodiment is used.

[0073] Fig. 14 is a flow diagram of the chamfering method according to the second embodiment. As shown in Fig. 14, the chamfering method according to the second embodiment includes a holding step S11, an outer peripheral edge detection step S12, a mark formation step S13, a chamfering step S14, a shape measurement step S15, and a judgment step S16. The holding step S11, the outer peripheral edge detection step S12, the chamfering step S14, the shape measurement step S15, and the judgment step S16 are the same as the holding step S1, the outer peripheral edge detection step S2, the chamfering step S3, the shape measurement step S4, and the judgment step S5 of the chamfering method according to the first embodiment, respectively.

[0074] That is, the chamfering method of the second embodiment differs from the chamfering method of the first embodiment only in that a mark forming step S13 is performed after the outer peripheral edge detection step S12 and before the chamfering step S14 and the shape measurement step S15. In the mark forming step S13, a laser beam is irradiated by the laser beam irradiating unit 12 to the outer peripheral portion of the workpiece 11, that is, near the outer peripheral edge (for example, near the orientation flat 11c), thereby forming an arbitrary mark.

[0075] Although there is no limit to the type of the mark formed in this mark forming step S13, the mark is typically a number such as a date or a serial number, a two-dimensional code, etc. Moreover, this mark forming step S13 is performed in a state in which the rotation drive source 8 of the holding unit 4 is not operating, that is, in a state in which the workpiece 11 is not rotating. Note that the mark forming step S13 may be performed after the chamfering step S14, before the shape measuring step S15, or after the shape measuring step S15.

[0076] [Third embodiment] Next, a chamfering apparatus and a chamfering method according to a third embodiment will be described. Fig. 15 is a schematic diagram of a chamfering apparatus 50 according to a third embodiment. The chamfering apparatus shown in Fig. 15 differs from the chamfering apparatus 2 according to the first embodiment in the configuration of a holding unit that holds the workpiece 11. The chamfering apparatus 50 according to this embodiment has, as a holding unit, a chuck table 52 configured in a disk shape having a substantially circular first surface 52a and a substantially circular second surface 52b.

[0077] A part of the first surface 52a of the chuck table 52 is made of a porous material and functions as a holding surface for holding the workpiece 11. A flow path (not shown) is provided inside the chuck table 52, one end of which opens to the holding surface. The other end of the flow path is connected to a suction source (not shown). With the second surface 11b of the workpiece 11 and the holding surface in contact with each other, negative pressure generated from the suction source is applied to the holding surface via the flow path, whereby the second surface 11b of the workpiece 11 is sucked into the holding surface and held thereon.

[0078] A rotation drive source (not shown) is connected to the second surface 52b side of the chuck table 52. The chuck table 52 rotates about a rotation axis 54 by a rotation drive force from the rotation drive source. In addition, a Z-axis movement mechanism (not shown) is connected to the chuck table 52. The Z-axis movement mechanism moves the chuck table 52 along the Z-axis direction.

[0079] The chamfering method of this embodiment is carried out in the same manner as the chamfering method of the first or second embodiment.

[0080] As described above, according to the chamfering device and the chamfering method of the first, second and third embodiments, appropriate chamfering of the workpiece 11 can be easily achieved.

[0081] In addition, the above-mentioned chamfering device 2 and chamfering device 50 irradiate the laser beam 38 onto the outer peripheral edge of the workpiece 11 while rotating the workpiece 11 using a rotary drive source. However, by using a focusing lens 16 with a diameter (width) larger than the diameter (width) of the workpiece 11 and adjusting the irradiation position of the laser beam 38 using only the deflector 18, it is possible to irradiate the laser beam 38 onto the entire outer peripheral edge of the workpiece 11 without rotating the workpiece 11.

[0082] In the above-described chamfering apparatus 2 and chamfering apparatus 50, the controller 26 performs image processing for detecting the outer periphery of the workpiece 11, but in cases where the position detector 22 has its own arithmetic device, the position detector 22 may perform image processing instead of the controller 26. Similarly, in cases where the shape measuring device 24 has its own arithmetic device, the shape measuring device 24 may calculate the shape of the workpiece 11 instead of the controller 26.

[0083] Furthermore, the controller 26 may store the shape of the workpiece 11 measured in the above-mentioned shape measuring step S4 and shape measuring step S15 in the storage device 36. This allows the shape of the workpiece 11 after the chamfering to be referred to as necessary in the process after the chamfering.

[0084] Furthermore, the above-described chamfering apparatus 2 and chamfering apparatus 50 may include a mechanism for moving the holding unit 4 in the X-axis direction and the Y-axis direction in addition to the Z-axis movement mechanism. The irradiation position of the laser beam 38 on the workpiece 11 may be adjusted by this mechanism.

[0085] In addition, the structures, methods, and the like according to the above-described embodiments and modified examples may be modified and implemented without departing from the scope of the present invention. [Explanation of symbols]

[0086] 11: Workpiece 11a: 1st page 11b: 2nd side 11c: Orientation Flat 2: Chamfering device 4: Holding unit 6: Adsorption member 8: Rotation drive source 10:Z-axis movement mechanism 12: Laser beam irradiation unit 14: Laser oscillator 16: Condenser lens 18: Deflector 20: Mirror 22: Position detector 24: Shape measuring device 26: Controller 28: Processing equipment 30: Outer edge position detection unit 32: Shape measurement section 34: Processing control section 36:Storage device 38: Laser beam 40:Reflected light 42: Rotation axis 44: Laser beam 46: Imaging area 48: Target shape 50: Chamfering device 52: Chuck table (holding unit) 52a: 1st page 52b: Side 2 54: Rotation axis

Claims

1. A chamfering device for chamfering a workpiece, comprising: A holding unit for holding the workpiece; a laser beam irradiation unit that irradiates the workpiece held by the holding unit with a laser beam for processing; a position detector used to detect the position of the outer periphery of the workpiece; a controller having a processing device and a storage device, and controlling operations of the holding unit, the laser beam irradiation unit, and the position detector in accordance with a program stored in the storage device; The laser beam irradiation unit includes: a laser oscillator for generating the laser beam by laser oscillation; a condenser lens for condensing the laser beam and directing it to the workpiece; a deflector disposed between the laser oscillator and the condenser lens, for deflecting the laser beam to displace a position at which the laser beam is incident on the condenser lens, thereby displacing an irradiation position on the workpiece where the laser beam is irradiated, The controller, according to the program, Calculating the position of the outer periphery of the workpiece using information obtained by the position detector; A chamfering device that operates the deflector to displace the irradiation position of the laser beam along the outer periphery.

2. 2. The chamfering apparatus according to claim 1, further comprising a shape measuring device used for measuring a shape of an outer periphery including the outer periphery of the workpiece.

3. The storage device stores information regarding a target shape of the outer periphery of the workpiece after machining, The controller, according to the program, 3. The chamfering device according to claim 2, further comprising a step of comparing the shape of the outer periphery indicated by the information obtained by the shape measuring device with the information on the target shape to determine whether the workpiece has been appropriately chamfered.

4. The controller, according to the program, The chamfering apparatus according to claim 3, wherein the laser beam irradiation unit is operated so as to change the conditions of the laser beam irradiated to the workpiece based on the results obtained by comparing the shape of the outer periphery indicated by the information obtained by the shape measuring device with the information regarding the target shape.

5. The controller, according to the program, 5. The chamfering device according to claim 1, wherein the laser beam irradiation unit is operated so that a mark is formed by the laser beam in an area inside the outer periphery of the workpiece based on the position of the outer periphery.

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