Cutting apparatus and cutting method for workpieces

Abstract

To provide a cutting device and a cutting method for a work-piece which can achieve desired processing without deteriorating through-put.SOLUTION: In cutting a work-piece utilizing a cutting blade that rotates at a rotation speed (a second rotation speed) which is different from a rotation speed (a first rotation speed) of the cutting blade at the time when a tip position of a tip of the cutting blade is detected by a detecting unit, a center position of the cutting blade is determined by reference to information showing change of an outer diameter of the cutting blade caused by change of the rotation speed of the cutting blade and the position of the tip of the cutting blade detected by the detecting unit. In this case, it is not necessary for the detecting unit to actually detect the position of the tip of the cutting blade, prior to cutting of the work-piece utilizing the cutting blade that rotates at the second rotation speed. This enables desired processing to be achieved without deteriorating through-put.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a cutting device that cuts a workpiece using an annular cutting blade and a method for cutting a workpiece.

Background Art

[0002] Chips of devices such as ICs (Integrated Circuits) are essential components in various electronic devices such as mobile phones and personal computers. Such chips are manufactured, for example, by dividing a workpiece such as a wafer having a large number of devices formed on its surface into regions each including an individual device. As a method for dividing the workpiece, for example, cutting in a cutting device can be mentioned.

[0003] This cutting device includes, for example, a chuck table capable of holding a workpiece and a cutting unit having a spindle to which an annular cutting blade is attached at its tip. In this cutting device, the workpiece is divided by bringing the cutting blade into contact with the workpiece held on the chuck table while rotating the cutting blade together with the spindle.

[0004] Here, when the workpiece is divided while the workpiece is in contact with the chuck table, the cutting blade may contact the chuck table and damage the chuck table. On the other hand, when cutting the workpiece without damaging the chuck table, there is a risk that the portion of the workpiece on the chuck table side remains without being removed, that is, the workpiece may not be divided.

[0005] Therefore, the workpiece is often carried onto the chuck table in a state of being adhered to a tape and is held on the chuck table via this tape (see, for example, Patent Document 1). When dividing the workpiece, the cutting blade is positioned so as to penetrate the workpiece and its tip reaches the inside of the tape. Thereby, the workpiece can be divided without damaging the chuck table.

[0006] However, the tip position of the cutting blade changes as the cutting blade wears down or is replaced. For this reason, cutting devices often include a detection unit for detecting the tip position of the cutting blade (see, for example, Patent Document 2). In this cutting device, the workpiece is divided by positioning the cutting blade so that it penetrates the workpiece and its tip reaches inside the tape, based on the tip position of the cutting blade detected by the detection unit. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2010-129623 [Patent Document 2] Japanese Patent Application Publication No. 8-174416 [Overview of the project] [Problems that the invention aims to solve]

[0008] To improve machining accuracy when dividing a workpiece, it is preferable to change the rotation speed of the cutting blade when cutting the workpiece according to the material or thickness of the workpiece. Similarly, to improve machining accuracy when cutting a workpiece to form a groove, it is preferable to change the rotation speed of the cutting blade when cutting the workpiece according to the depth of the groove.

[0009] However, when the rotational speed of the cutting blade changes, the centrifugal force acting on the cutting blade also changes, causing its outer diameter to increase or decrease, that is, the tip position of the cutting blade also changes. Therefore, in order to reliably divide the workpiece without damaging the chuck table, or to form a groove of a desired depth in the workpiece, it is preferable to detect the tip position of the cutting blade using a detection unit each time the rotational speed of the cutting blade is changed.

[0010] However, if the tip position of the cutting blade is detected by a detection unit each time the rotational speed of the cutting blade is changed, the throughput of the cutting device decreases. In view of this, the object of the present invention is to provide a cutting device and a cutting method for a workpiece that can achieve desired processing without reducing throughput. [Means for solving the problem]

[0011] According to one aspect of the present invention, a cutting apparatus for cutting a workpiece using an annular cutting blade comprises a chuck table capable of holding the workpiece, a cutting unit having a spindle on which the cutting blade is mounted at its tip, a detection unit for detecting the tip position of the cutting blade, and a control unit for controlling the chuck table, the cutting unit and the detection unit, wherein the control unit has a storage unit for storing information indicating the change in the outer diameter of the cutting blade in accordance with a change in the rotational speed of the cutting blade, and together with the spindle At the first rotational speed A detection unit controls the cutting unit and the detection unit to detect the tip position of the rotating cutting blade, and together with the spindle At the first rotational speed or a second rotational speed different from the first rotational speed The cutting unit comprises a cutting section that controls the chuck table and the cutting unit, so as to cut the workpiece held by the chuck table using the rotating cutting blade, and the cutting section The second When cutting a workpiece using the cutting blade that rotates at a rotational speed, Without using the detection unit, The information stored in the memory unit and the information detected by the detection unit Rotating at the first rotational speed A cutting device is provided that determines the center position of the cutting blade by referring to the tip position of the cutting blade.

[0012] According to another aspect of the present invention, a cutting apparatus comprising a chuck table capable of holding a workpiece, a cutting unit having a spindle with an annular cutting blade mounted at its tip, a detection unit for detecting the tip position of the cutting blade, and a control unit for controlling the chuck table, the cutting unit, and the detection unit, wherein a method for cutting a workpiece using the cutting blade is provided, comprising a storage step of storing information indicating the change in the outer diameter of the cutting blade in accordance with a change in the rotational speed of the cutting blade in a storage unit of the control unit, and while rotating the cutting blade at a first rotational speed, the tip position of the cutting blade is detected using the detection unit The system comprises: a detection step of actually detecting; a first cutting step of using the cutting blade to cut the workpiece held by the chuck table while rotating the cutting blade at a first rotational speed; and a second cutting step of using the cutting blade to cut the workpiece held by the chuck table or another workpiece while rotating the cutting blade at a second rotational speed different from the first rotational speed, wherein the center position of the cutting blade in the first cutting step is determined by referring to the tip position of the cutting blade detected in the detection step, and the center position of the cutting blade in the second cutting step is Without using the detection unit, A method for cutting a workpiece is provided, which is determined by referring to the information stored in the storage step and the tip position of the cutting blade detected in the detection step.

[0013] Furthermore, preferably, the information is a table showing the correspondence between a plurality of rotational speeds, including a reference rotational speed, and the amount of change in the outer diameter of the cutting blade when the cutting blade is rotated at any of the plurality of rotational speeds, wherein the amount of change is the difference from the outer diameter of the cutting blade when the cutting blade is rotated at the reference rotational speed.

[0014] Alternatively, preferably, the information is a function for calculating the change in the outer diameter of the cutting blade, with the rotational speed of the cutting blade as a variable, wherein the change is the difference between the outer diameter of the cutting blade when the cutting blade is rotated at a reference rotational speed and the outer diameter of the cutting blade when the cutting blade is rotated at a reference rotational speed.

Advantages of the Invention

[0015] In the present invention, when machining a workpiece using a cutting blade that rotates at a rotational speed (second rotational speed) different from the rotational speed (first rotational speed) of the cutting blade when the tip position of the cutting blade is detected by the detection unit, the information indicating the change in the outer diameter of the cutting blade accompanying the change in the rotational speed of the cutting blade and the tip position of the cutting blade detected by the detection unit are referred to, and the center position of the cutting blade is determined.

[0016] In this case, prior to cutting the workpiece using the cutting blade that rotates at the second rotational speed, it is not necessary to actually detect the tip position of the cutting blade by the detection unit. Therefore, in the present invention, it is possible to achieve desired machining without reducing the throughput.

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is a perspective view schematically showing an example of a frame unit including a workpiece. [Figure 2] FIG. 2 is a perspective view schematically showing an example of a cutting device capable of cutting a workpiece. [Figure 3] FIG. 3 is a perspective view showing an enlarged view of a detection unit and a cutting unit included in the cutting device. [Figure 4] FIG. 4 is a functional block diagram schematically showing an example of a control unit. [Figure 5] FIG. 5 is a front view schematically showing a state of detecting the tip position of the cutting blade. [Figure 6] FIG. 6 is a partially sectional front view schematically showing a state of cutting a workpiece. [Figure 7] FIG. 7 is a flowchart schematically showing an example of a method for cutting a workpiece in a cutting device.

Embodiments for Carrying Out the Invention

[0018] Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing an example of a frame unit including a workpiece. The frame unit 11 shown in FIG. 1 has a disk-shaped workpiece 13 with its surface 13a exposed. This workpiece 13 is, for example, a wafer made of a single crystal semiconductor material such as silicon (Si), silicon carbide (SiC), or gallium nitride (GaN).

[0019] Furthermore, on the surface 13a side of the workpiece 13, a plurality of devices 15 are arranged in a matrix. That is, the boundaries of the plurality of devices 15 extend in a lattice pattern. Also, on the back surface 13b of the workpiece 13, the central region of a disk-shaped tape 17 having a diameter larger than that of the workpiece 13 is attached.

[0020] This tape 17 has, for example, a flexible film-shaped tape substrate and an adhesive layer (paste layer) provided on the workpiece 13 side of this tape substrate. And the tape substrate is made of polyolefin (PO), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polystyrene (PS), or the like. Also, the adhesive layer is made of an ultraviolet curable silicone rubber, an acrylic-based material, an epoxy-based material, or the like.

[0021] Also, an annular frame 19 having an inner diameter larger than the diameter of the workpiece 13 is attached to the outer peripheral region of the tape 17. This annular frame 19 is made of a metal material such as aluminum or stainless steel, for example.

[0022] FIG. 2 is a perspective view schematically showing an example of a cutting device capable of cutting the workpiece 13. Note that the X-axis direction (front-rear direction) and the Y-axis direction (left-right direction) shown in FIG. 2 are directions orthogonal to each other on a horizontal plane, and the Z-axis direction (up-down direction) is a direction (vertical direction) orthogonal to each of the X-axis direction and the Y-axis direction.

[0023] The cutting apparatus 2 shown in Figure 2 includes a base 4 that supports each component. A recess 4a extending along the X-axis is formed on the upper surface of the base 4. Inside the recess 4a, a flat table cover 6 and a bellows-shaped dustproof and dripproof cover 8 that expands and contracts as the table cover 6 moves are provided.

[0024] Furthermore, a chuck table 10 is provided above the table cover 6. This chuck table 10 has a disc-shaped frame 10a made of ceramics or the like. The frame 10a has a disc-shaped bottom wall and cylindrical side walls that rise from this bottom wall. A disc-shaped porous plate 10b made of porous ceramics, for example, is fixed to the recess defined by the bottom wall and side walls of the frame 10a.

[0025] The porous plate 10b has a diameter approximately equal to the inner diameter of the side wall of the frame 10a. Furthermore, the porous plate 10b communicates with a suction source (not shown), such as an ejector, provided inside the recess 4a, through a through hole or the like formed in the bottom wall of the frame 10a. In addition, the upper surface of the side wall of the frame 10a and the upper surface of the porous plate 10b are generally flat surfaces perpendicular to the Z-axis direction and function as holding surfaces for the chuck table 10.

[0026] Specifically, when the frame unit 11 is loaded into the cutting device 2, the workpiece 13 is placed on the holding surface of the chuck table 10 via the tape 17. Then, when the suction source communicating with the porous plate 10b is activated, a suction force acts on the workpiece 13 via the tape 17, and the workpiece 13 is held by the chuck table 10.

[0027] Furthermore, multiple clamps 12 are provided around the chuck table 10. The multiple clamps 12 are provided at approximately equal angular intervals along the circumferential direction of the chuck table 10. When the frame unit 11 is loaded into the cutting device 2, the multiple clamps 12 grip the annular frame 19 at a position lower than the holding surface of the chuck table 10.

[0028] Furthermore, the chuck table 10 and the multiple clamps 12 are connected to a ball screw type X-axis movement mechanism (not shown) located inside the recess 4a. When this X-axis movement mechanism is operated, the chuck table 10 and the multiple clamps 12 move along the X-axis. In addition, as these move, the table cover 6 also moves along the X-axis, and the dustproof and waterproof cover 8 expands and contracts.

[0029] Furthermore, the chuck table 10 and the multiple clamps 12 are connected to a rotational drive source (not shown), such as a motor, which is located inside the recess 4a. When this rotational drive source is operated, the chuck table 10 and the multiple clamps 12 rotate around a straight line passing through the center of the upper surface of the porous plate 10b and along the Z-axis direction as the axis of rotation.

[0030] Furthermore, a detection unit 14 for detecting the tip position of the cutting blade 40, which will be described later, is provided at the corner of the upper surface of the table cover 6. Details of the structure of the detection unit 14 and the method by which the detection unit 14 detects the tip position of the cutting blade 40 will be described later.

[0031] A support structure 16 is provided in the area near the recess 4a on the upper surface of the base 4. This support structure 16 has an upright portion 16a extending along the Z-axis from the upper surface of the base 4, and an arm portion 16b extending along the Y-axis from the upper end of the upright portion 16a so as to span the recess 4a. A Y-axis movement mechanism 18 is provided on the front side of the arm portion 16b.

[0032] This Y-axis movement mechanism 18 is fixed to the front of the arm portion 16b and has a pair of Y-axis guide rails 20 that extend along the Y-axis direction. A Y-axis movement plate 22 is connected to the front side of the pair of Y-axis guide rails 20 in a manner that allows it to slide along the pair of Y-axis guide rails 20.

[0033] Furthermore, a screw shaft 24 extending along the Y-axis direction is positioned between the pair of Y-axis guide rails 20. A motor (not shown) for rotating the screw shaft 24 is connected to one end of this screw shaft 24. A nut (not shown) for housing a number of balls that roll on the surface of the rotating screw shaft 24 is provided on the surface of the screw shaft 24, where a helical groove is formed, thus forming a ball screw.

[0034] In other words, as the screw shaft 24 rotates, numerous balls circulate within the nut, causing the nut to move along the Y-axis direction. This nut is fixed to the rear side of the Y-axis moving plate 22. Therefore, by rotating the screw shaft 24 with a motor connected to one end of the screw shaft 24, the Y-axis moving plate 22 moves along the Y-axis direction along with the nut.

[0035] A Z-axis movement mechanism 26 is provided on the front side of the Y-axis movement plate 22. This Z-axis movement mechanism 26 has a pair of Z-axis guide rails 28 that are fixed to the front of the Y-axis movement plate 22 and extend along the Z-axis direction. The Z-axis movement plate 30 is connected to the front side of the pair of Z-axis guide rails 28 in a manner that allows it to slide along the pair of Z-axis guide rails 28.

[0036] Furthermore, a screw shaft 32 extending along the Z-axis direction is positioned between a pair of Z-axis guide rails 28. A motor 34 for rotating the screw shaft 32 is connected to one end of this screw shaft 32. A nut (not shown) is provided on the surface of the screw shaft 32, where a helical groove is formed, to accommodate a number of balls that roll on the surface of the rotating screw shaft 32, thus forming a ball screw.

[0037] In other words, as the screw shaft 32 rotates, numerous balls circulate within the nut, causing the nut to move along the Z-axis direction. This nut is fixed to the rear side of the Z-axis moving plate 30. Therefore, when the screw shaft 32 is rotated by the motor 34, the Z-axis moving plate 30 moves along the Z-axis direction along with the nut.

[0038] A cutting unit 36 ​​is fixed to the lower part of the Z-axis moving plate 30. This cutting unit 36 ​​has a cylindrical spindle housing 38 that extends along the Y-axis direction and an annular cutting blade 40 whose tip position is detected by the detection unit 14. Figure 3 is an enlarged perspective view showing the detection unit 14 and the cutting unit 36.

[0039] The spindle housing 38 of the cutting unit 36 ​​houses a cylindrical spindle 42 that extends along the Y-axis. This spindle 42 is supported by the spindle housing 38 in a rotatable manner. The tip of the spindle 42 protrudes outside the spindle housing 38, and a cutting blade 40 having an annular cutting edge 40a is mounted on this tip.

[0040] Furthermore, the base end of the spindle 42 is connected to a rotational drive source (not shown), such as a motor, which is built into the spindle housing 38. When this rotational drive source is operated, the cutting blade 40 rotates together with the spindle 42, with a straight line along the Y-axis as the axis of rotation. The cutting blade 40 is mounted on the spindle 42 such that the straight line that forms the axis of rotation of the spindle 42 passes through the center of the cutting blade 40.

[0041] Furthermore, the detection unit 14 has a detector 44. This detector 44 includes a rectangular parallelepiped support portion 44a and a detection portion 44b provided above the rear end of the support portion 44a. The upper end of the detection portion 44b has a blade entry portion 44c formed in which a notch is cut out in such a manner that the cutting edge 40a of the cutting blade 40 can enter.

[0042] A pair of columnar sections are provided on both sides of the blade entry section 44c in the Y-axis direction. A light-emitting section 46 and a light-receiving section 48 are housed in the pair of columnar sections, facing each other via the blade entry section 44c.

[0043] The light-emitting unit 46 is connected to a light source (not shown), such as an LED, via an optical fiber or the like, and emits light toward the light-receiving unit 48. The light-receiving unit 48 is connected to a photoelectric conversion unit (not shown) via an optical fiber or the like. This photoelectric conversion unit includes, for example, a photoelectric conversion element and generates a voltage corresponding to the amount of light received by the light-receiving unit 48.

[0044] Furthermore, two air supply nozzles 50 for supplying air to the light-emitting unit 46 and the light-receiving unit 48 are provided on the upper surface of the support unit 44a located in front of the detection unit 44b. Also, two liquid supply nozzles 52 for supplying liquid such as water to the light-emitting unit 46 and the light-receiving unit 48 are provided adjacent to the air supply nozzles 50. The light-emitting unit 46 and the light-receiving unit 48 are then washed with liquid supplied from, for example, the liquid supplied from the liquid supply nozzles 52, and then dried with air supplied from the air supply nozzles 50.

[0045] A rectangular parallelepiped cover portion 56 is attached to the rear end face of the detector 44 via a connector 54, which consists of a hinge or the like. The inside of this cover portion 56 is hollow. Therefore, for example, by rotating the cover portion 56 around the connector 54, the detection unit 44b, the air supply nozzle 50, the liquid supply nozzle 52, etc., are housed inside the cover portion 56.

[0046] Then, when the detection unit 14 detects the tip position of the cutting blade 40 (the lower end position of the cutting edge 40a), the cover portion 56 is opened to expose the detection portion 44b, the air supply nozzle 50, and the liquid supply nozzle 52, etc. This allows the cutting edge 40a of the cutting blade 40 to enter the blade entry portion 44c, enabling the detection of the tip position of the cutting blade 40.

[0047] Furthermore, as shown in Figure 2, an imaging unit 58 is provided adjacent to the cutting unit 36 ​​in the X-axis direction, fixed to the lower part of the Z-axis moving plate 30. This imaging unit 58 includes, for example, a light source such as an LED (Light Emitting Diode), an objective lens, and an image sensor such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0048] Furthermore, the cutting device 2 incorporates a control unit that controls the components described above. Figure 4 is a schematic functional block diagram showing an example of the control unit of the cutting device 2. The control unit 60 shown in Figure 4 has a processing unit 62 and a storage unit 64.

[0049] The processing unit 62 is composed of a processor, such as a CPU (Central Processing Unit). The storage unit 64 is composed of volatile memory, such as DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory), and non-volatile memory, such as an SSD (Solid State Drive) (NAND flash memory) or an HDD (Hard Disk Drive) (magnetic storage device).

[0050] The storage unit 64 stores various types of information (data, programs, etc.) used in the processing unit 62. For example, the storage unit 64 stores information indicating the change in the outer diameter of the cutting blade 40 in response to a change in the rotational speed of the cutting blade 40.

[0051] This information is used when cutting the workpiece 13 using a cutting blade 40 that rotates at a different rotational speed than the cutting blade 40's rotational speed at which the detection unit 14 detected the tip position of the cutting blade 40. An example of cutting the workpiece 13 using this information will be described later.

[0052] Furthermore, the processing unit 62 reads and executes various programs stored in the storage unit 64 to control the components of the cutting device 2. This processing unit 62 includes, for example, a detection unit 66 and a cutting unit 68.

[0053] The detection unit 66 controls the cutting unit 36 ​​and the detection unit 14 to detect the tip position of the cutting blade 40 that rotates together with the spindle 42. Figure 5 is a schematic front view showing how the detection unit 66 controls the cutting unit 36 ​​and the detection unit 14 to detect the tip position of the cutting blade 40 that rotates together with the spindle 42.

[0054] When detecting the tip position of the cutting blade 40, the detection unit 66 first controls the X-axis movement mechanism, which moves the chuck table 10 along the X-axis, and / or the Y-axis movement mechanism 18, which moves the cutting unit 36 ​​along the Y-axis, so that the cutting blade 40 is positioned directly above the blade entry portion 44c of the detector 44.

[0055] Next, the detection unit 66 controls the rotation drive source built into the spindle housing 38 so that the cutting blade 40 rotates at a predetermined rotational speed (first rotational speed). Then, the detection unit 66 controls the light source connected to the light-emitting unit 46 so that light L is irradiated from the light-emitting unit 46 toward the light-receiving unit 48.

[0056] Next, the detection unit 66 controls the Z-axis movement mechanism 26 to rotate the cutting blade 40 and, while continuing to irradiate light L from the light-emitting unit 46 toward the light-receiving unit 48, to move the cutting blade 40 into the blade entry portion 44c of the detector 44.

[0057] As a result, the light L irradiated from the light-emitting unit 46 to the light-receiving unit 48 is partially blocked by the cutting blade 40, and the amount of light received by the light-receiving unit 48 gradually decreases (see Figure 5). Furthermore, the voltage generated in the photoelectric conversion unit connected to the light-receiving unit 48 also gradually decreases accordingly.

[0058] Furthermore, this voltage is input to the control unit 60 as a signal indicating the amount of light received by the light receiving unit 48. The control unit 60 then uses a detection unit 66 to detect the position (height) of the cutting blade 40 in the Z-axis direction when this voltage value reaches a predetermined value, and uses this as the tip position of the cutting blade 40. This predetermined value is stored, for example, in a storage unit 64.

[0059] The cutting unit 68 controls the chuck table 10 and the cutting unit 36 ​​to cut the workpiece 13 held by the chuck table 10 using a cutting blade 40 that rotates together with the spindle 42. Figure 6 is a schematic partial cross-sectional front view showing how the cutting unit 68 controls the chuck table 10 and the cutting unit 36 ​​to cut the workpiece 13 held by the chuck table 10 using a cutting blade 40 that rotates together with the spindle 42.

[0060] When cutting the workpiece 13, first, the workpiece 13 is placed on the holding surface of the chuck table 10 via the tape 17. Next, the cutting unit 68 controls a suction source that communicates with the porous plate 10b of the chuck table 10 so that the workpiece 13 is held by the chuck table 10.

[0061] Next, the cutting unit 68 controls the rotational drive source connected to the chuck table 10 so that the linear portion (planned division line) included in the boundary of the multiple devices 15 formed on the workpiece 13 becomes parallel to the X-axis direction.

[0062] Next, the cutting unit 68 controls an X-axis movement mechanism that moves the chuck table 10 along the X-axis direction and / or a Y-axis movement mechanism 18 that moves the cutting unit 36 ​​along the Y-axis direction, so that the planned division line parallel to the X-axis direction is positioned in the X-axis direction when viewed from the cutting edge 40a of the cutting blade 40 in a plan view.

[0063] Next, the cutting unit 68 controls the rotational drive source built into the spindle housing 38 to rotate the cutting blade 40 together with the spindle 42. Then, the cutting unit 68 controls the Z-axis movement mechanism 26 so that the tip position of the cutting blade 40 is at a height corresponding to the tape 17, that is, lower than the back surface 13b of the workpiece 13 and higher than the holding surface of the chuck table 10.

[0064] At this time, the cutting unit 68 controls the Z-axis movement mechanism 26 to shift the center position of the cutting blade 40 (the position of the straight line that forms the rotation axis of the spindle 42) according to the rotational speed of the cutting blade 40. Specifically, when the rotational speed of the cutting blade 40 changes, the centrifugal force acting on the cutting blade 40 also changes, and its outer diameter (outer diameter of the cutting edge 40a) increases or decreases, that is, the tip position of the cutting blade 40 also changes.

[0065] Therefore, in order to position the tip of the cutting blade 40 at the desired position (height), it is necessary to move the center position of the cutting blade 40 so as to compensate for the increase or decrease in the outer diameter of the cutting blade 40. Table 1 below shows the correspondence between multiple rotational speeds, including the reference rotational speed, and the amount of change in the outer diameter of the cutting blade 40 when the cutting blade 40 is rotated at any of the multiple rotational speeds.

[0066] Specifically, in Table 1 below, 10,000 rpm (rotations per minute) is set as the reference rotational speed. Furthermore, in Table 1 below, the difference between the outer diameter of the cutting blade 40 and the rotational speed of the cutting blade 40 at 10,000 rpm (rotations per minute) is shown as the change in outer diameter. [Table 1]

[0067] The data corresponding to Table 1 is stored, for example, in the memory unit 64 as information showing the change in the outer diameter of the cutting blade 40 in response to a change in the rotational speed of the cutting blade 40. When the outer diameter of the cutting blade 40 changes in accordance with the rotational speed as shown in Table 1, the cutting unit 68 needs to move the center position of the cutting blade 40 as shown in Table 2 below. [Table 2]

[0068] In other words, the cutting unit 68 controls the Z-axis movement mechanism 26 such that when the cutting blade 40 is rotated at, for example, 60,000 rpm, its center position is 11 μm higher compared to when it is rotated at 10,000 rpm.

[0069] Next, the cutting unit 68 controls the X-axis movement mechanism located inside the recess 4a so that the cutting blade 40 moves from one end to the other in the X-axis direction of the workpiece 13 while the cutting blade 40 is still rotating (see Figure 6).

[0070] In other words, the chuck table 10, which holds the workpiece 13, is moved along the X-axis direction with the cutting blade 40 positioned so that it penetrates the workpiece 13 and its tip reaches the inside of the tape 17. As a result, a groove 11a is formed in the frame unit 11 on its bottom surface, exposing the tape 17, and the workpiece 13 is divided along the planned division line.

[0071] Figure 7 is a schematic flowchart illustrating an example of a workpiece cutting method used by the cutting device 2 to cut the workpiece 13. In this method, first, information indicating the change in the outer diameter of the cutting blade 40 due to a change in the rotational speed of the cutting blade 40 is stored (storage step: S1). Specifically, in this storage step (S1), the storage unit 64 of the control unit 60 is used to store, for example, data corresponding to Table 1 above.

[0072] Next, while rotating the cutting blade 40 at the first rotational speed, the tip position of the cutting blade 40 is actually detected (detection step: S2). Specifically, as explained with reference to Figure 5, the detection unit 66 controls the cutting unit 36 ​​and the detection unit 14. The first rotational speed is a rotational speed suitable for cutting the workpiece 13, for example, 10,000 rpm.

[0073] Next, the workpiece 13 is cut while the cutting blade 40 is rotated at a first rotational speed (first cutting step: S3). Specifically, as explained with reference to Figure 6, the cutting unit 68 controls the chuck table 10 and the cutting unit 36.

[0074] Furthermore, the rotational speed of the cutting blade 40 in the first cutting step (S3) is the same as the rotational speed of the cutting blade 40 in the detection step (S2). Therefore, the center position of the cutting blade 40 in the first cutting step (S3) is determined by referring to the tip position of the cutting blade 40 detected in the detection step (S2), without referring to the information stored in the storage step (S1).

[0075] Next, while rotating the cutting blade 40 at a second rotational speed, another workpiece 13 different from the workpiece 13 is cut (second cutting step: S4). Specifically, as explained with reference to Figure 6, the cutting unit 68 controls the chuck table 10 and the cutting unit 36.

[0076] Note that the other workpiece 13 differs in material and / or thickness from the workpiece 13 cut in the first cutting step (S3). The second rotational speed is a rotational speed suitable for cutting the other workpiece 13, for example, 60,000 rpm.

[0077] Then, the center position of the cutting blade 40 in the second cutting step (S4) is determined by referring to the information stored in the storage step (S1) and the tip position of the cutting blade 40 detected in the detection step (S2). In other words, in this case, the center position of the cutting blade 40 is 11 μm higher than the position determined by referring only to the tip position of the cutting blade 40 detected in the detection step (S2).

[0078] In the cutting device 2, when cutting the workpiece 13 using a cutting blade 40 that rotates at a different rotational speed (second rotational speed) than the rotational speed (first rotational speed) at which the tip position of the cutting blade 40 was detected by the detection unit 14, that is, in the second cutting step (S4), the center position of the cutting blade 40 is determined by referring to information indicating the change in the outer diameter of the cutting blade 40 due to the change in the rotational speed of the cutting blade 40 and the tip position of the cutting blade 40 detected by the detection unit 14.

[0079] In this case, prior to cutting the workpiece 13 using the cutting blade 40 rotating at the second rotational speed, it is not necessary for the detection unit 14 to actually detect the tip position of the cutting blade 40. Therefore, the cutting device 2 can achieve the desired machining without reducing throughput.

[0080] It should be noted that the above description represents only one aspect of the present invention, and the present invention is not limited to the above description. For example, the information showing the change in the outer diameter of the cutting blade 40 due to a change in the rotational speed of the cutting blade 40 is not limited to Table 1 above, but may also be a function (f(r)) for calculating the amount of change in the outer diameter of the cutting blade 40 with the rotational speed (r) of the cutting blade 40 as a variable.

[0081] The following equations (1) and (2) are examples of functions for calculating the change in the outer diameter of the cutting blade 40, which changes in outer diameter according to the rotational speed as shown in Table 1. Specifically, equation (1) is a quadratic equation for calculating this change, and equation (2) is a cubic equation for calculating this change.

number

number

[0082] If the information indicating the change in the outer diameter of the cutting blade 40 due to a change in the rotational speed of the cutting blade 40 is the above function, it is preferable because it makes it possible to grasp the change in the outer diameter of the cutting blade 40 at various rotational speeds (for example, 33333 rpm).

[0083] Furthermore, the cutting device 2 may be used not to divide the workpiece 13, but to form a groove in the workpiece 13. That is, in the cutting device 2, the workpiece 13 may be cut with the cutting blade 40 positioned so that its tip remains inside the workpiece 13 without penetrating it.

[0084] Furthermore, in the second cutting step (S4), the same workpiece 13 that was cut in the first cutting step (S3) may be cut. For example, in the second cutting step (S4), the workpiece 13 may be cut in such a way that it divides the workpiece 13 that had grooves formed in the first cutting step (S3).

[0085] Furthermore, the structures and methods of the embodiments described above can be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0086] 2:Cutting device 4: Base (4a: Recess) 6: Table cover 8: Dustproof and waterproof cover 10: Chuck table (10a: frame, 10b: porous plate) 11: Frame unit (11a: Groove) 12: Clamp 13: Workpiece (13a: front side, 13b: back side) 14: Detection Unit 15: Device 16: Support structure (16a: standing part, 16b: arm part) 17: Tape 18:Y-axis direction movement mechanism 19: Ring frame 20: Y-axis guide rail 22: Y-axis movement plate 24: Screw shaft 26:Z-axis direction movement mechanism 28: Z-axis guide rail 30: Z-axis movement plate 32: Screw shaft 34: Motor 36: Cutting Unit 38: Spindle Housing 40: Cutting blade (40a: Cutting edge) 42: Spindle 44: Detector (44a: Support part, 44b: Detection part, 44c: Blade entry part) 46: Light-emitting part 48: Light receiving part 50: Air supply nozzle 52: Liquid supply nozzle 54: Connector 56: Cover section 58: Imaging Unit 60: Control Unit 62: Processing Unit 64: Storage section 66: Detection unit 68: Cutting part

Claims

1. A cutting device that cuts a workpiece using an annular cutting blade, A chuck table capable of holding the workpiece, A cutting unit having a spindle on which the cutting blade is attached at the tip, A detection unit for detecting the tip position of the cutting blade, The system comprises a chuck table, a cutting unit, and a control unit that controls the detection unit, The control unit is, A storage unit that stores information indicating the change in the outer diameter of the cutting blade due to a change in the rotational speed of the cutting blade, A detection unit controls the cutting unit and the detection unit so as to detect the tip position of the cutting blade which rotates with the spindle at a first rotational speed, The system includes a cutting unit that controls the chuck table and the cutting unit, so as to cut the workpiece held by the chuck table using the cutting blade which rotates together with the spindle at a first rotational speed or a second rotational speed different from the first rotational speed, The cutting unit is a cutting device that, when cutting a workpiece using the cutting blade rotating at the second rotational speed, determines the center position of the cutting blade by referring to the information stored in the storage unit and the tip position of the cutting blade rotating at the first rotational speed detected by the detection unit, without using the detection unit.

2. This information is a table showing the correspondence between multiple rotational speeds, including a reference rotational speed, and the amount of change in the outer diameter of the cutting blade when the cutting blade is rotated at any of these multiple rotational speeds. The cutting apparatus according to claim 1, wherein the amount of change is the difference between the outer diameter of the cutting blade when the cutting blade is rotated at the reference rotational speed.

3. This information is a function for calculating the change in the outer diameter of the cutting blade, with the rotational speed of the cutting blade as a variable. The cutting apparatus according to claim 1, wherein the amount of change is the difference between the outer diameter of the cutting blade when it is rotated at a reference rotational speed and the outer diameter of the cutting blade.

4. A chuck table capable of holding a workpiece, A cutting unit having a spindle with an annular cutting blade attached to its tip, A detection unit for detecting the tip position of the cutting blade, A cutting apparatus comprising a chuck table, a cutting unit, and a control unit for controlling the detection unit, wherein a method for cutting a workpiece is performed using the cutting blade, A storage step involves storing information in the storage unit of the control unit that indicates the change in the outer diameter of the cutting blade due to a change in the rotational speed of the cutting blade, A detection step in which the cutting blade is rotated at a first rotational speed, and the tip position of the cutting blade is actually detected using the detection unit, A first cutting step involves rotating the cutting blade at the first rotational speed and using the cutting blade to cut the workpiece held by the chuck table, The apparatus comprises a second cutting step in which the cutting blade is rotated at a second rotational speed different from the first rotational speed, and the cutting blade is used to cut the workpiece held by the chuck table or another workpiece, The center position of the cutting blade in the first cutting step is determined by referring to the tip position of the cutting blade detected in the detection step. A method for cutting a workpiece in which the center position of the cutting blade in the second cutting step is determined by referring to the information stored in the storage step and the tip position of the cutting blade detected in the detection step, without using the detection unit.

5. This information is a table showing the correspondence between multiple rotational speeds, including a reference rotational speed, and the amount of change in the outer diameter of the cutting blade when the cutting blade is rotated at any of these multiple rotational speeds. The method for cutting a workpiece according to claim 4, wherein the amount of change is the difference between the outer diameter of the cutting blade when the cutting blade is rotated at the reference rotational speed.

6. This information is a function for calculating the change in the outer diameter of the cutting blade, with the rotational speed of the cutting blade as a variable. The method for cutting a workpiece according to claim 4, wherein the amount of change is the difference between the outer diameter of the cutting blade when the cutting blade is rotated at a reference rotational speed and the outer diameter of the cutting blade.

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