Blade breakage detection device

Abstract

To provide a blade breakage detection device capable of detecting a chip generated on only one surface of an outer peripheral part of a blade.SOLUTION: The blade breakage detection device includes a light irradiation means for irradiating light passing through a first lens (light projection part side lens 50) having an optical axis parallel to a rotation axis (C) of a blade (102) toward an outer peripheral part of the blade, a light reception means for receiving light passing through a second lens (light reception part side lens 52) facing the first lens (50) across the outer peripheral part of the blade and having the same optical axis as the optical axis, and a detection means (breakage detection part) for detecting breakage of the blade based on a light reception result of the light reception means.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a blade breakage detection device that detects blade breakage by irradiating a blade with light. [Background technology]

[0002] A dicing machine, which divides a wafer with multiple devices formed on its surface into individual chips, is equipped with a blade that is rotated at high speed by a spindle and a table that holds the wafer by suction. In the dicing process, which is part of the semiconductor manufacturing process, the blade of the dicing machine is rotated at high speed to groove or cut the wafer that is held by suction on the table.

[0003] In addition, the dicing process may include a grinding process to thin the wafer. When the wafer is ground thin in the grinding process, the outer periphery of the wafer may become a knife edge, which can cause processing defects. Therefore, to prevent the occurrence of knife edges, a process called edge trimming may be implemented, in which a blade is used to create a step on the outer periphery of the wafer.

[0004] Here, when edge trimming is performed, a blade thicker than usual may be used depending on the amount of edge removal. Even when a rotating blade is used to process the surface of a wafer, as is typically done in a dicing process, a thick blade may be used not for the purpose of dividing the wafer into chips, but for the purpose of forming the shape of the groove itself. While the thickness of a blade typically used is several μm, the thickness of the thick blade mentioned above is 1 mm to 5 mm.

[0005] Various technologies have been proposed for detecting damage to the blade of a dicing device. For example, Patent Document 1 describes a blade damage detection device that receives light emitted from a light-emitting unit with a light-receiving unit and detects damage to the blade depending on the amount of light received. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-83077 Summary of the Invention [Problem to be solved by the invention]

[0007] The blade breakage detection device described in Patent Document 1 employs a configuration in which a light emitting unit emits light parallel to the rotation axis of the blade and a light receiving unit receives the light. However, with this configuration, for example, if a chip occurs on only one side of the outer periphery of a thick blade, the chip may not be detected.

[0008] In addition, in the past, thick blades were inspected for chipping only on the outer periphery of the front or back surface only after an abnormality occurred in a diced product. In this inspection, an operator visually checks the condition of the blade using a microscope or other device to detect chipping. In this way, when an operator visually detects blade damage, the blade must be temporarily removed from the dicing machine, during which the dicing machine cannot be operated, resulting in reduced productivity. Furthermore, because an operator only checks the blade once an abnormality occurs in a diced product, there is a risk of producing a large number of defective products.

[0009] The present invention has been made in view of the above circumstances, and its object is to provide a damage detection device that can detect chipping that occurs on only one surface of the outer periphery of a blade. [Means for solving the problem]

[0010] One aspect of the present invention for achieving the above-mentioned object is a blade breakage detection device for detecting breakage in a rotatable blade, and comprises a light irradiating means for irradiating light obliquely with respect to the rotation axis of the blade toward the outer periphery of the blade, a light receiving means for receiving light irradiated from the light irradiating means and transmitted through the outer periphery of the blade, and a detection means for detecting breakage of the blade based on the light reception result of the light receiving means.

[0011] According to this aspect, the light is irradiated toward the outer periphery of the blade at an angle to the rotation axis of the blade, making it possible to detect chips that have occurred on only one side of the outer periphery of the blade.

[0012] Preferably, the light irradiating means has a light emitting element that emits light having an optical axis extending from one end to the other end across the outer periphery of the blade.

[0013] Preferably, the angle of inclination of the optical axis relative to the rotation axis of the blade is in the range of 30 to 60 degrees.

[0014] Another aspect of the present invention is a blade breakage detection device for detecting breakage in a rotatable blade, and comprises a light irradiation means for irradiating light that has passed through a first lens having an optical axis parallel to the rotation axis of the blade toward the outer periphery of the blade, a light receiving means that faces the first lens across the outer periphery of the blade and receives light that has passed through a second lens having the same optical axis as the first lens, and a detection means that detects breakage of the blade based on the light reception results of the light receiving means.

[0015] According to this aspect, the light that has passed through the first lens is directed toward the outer periphery of the blade, and the light that has passed through the second lens is received, making it possible to detect chips that have occurred on only one side of the outer periphery of the blade.

[0016] Preferably, the numerical aperture NA of the first lens and the second lens is 0.4 or greater.

[0017] Preferably, the focal positions of the first lens and the second lens are located at the center of the blade in the width direction. [Effects of the Invention]

[0018] According to the present invention, chipping occurring on only one surface of the outer periphery of the blade can be detected. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view showing the appearance of a dicing machine equipped with a blade breakage detection device. [Figure 2] FIG. 2 is a perspective view showing the configuration of the processing unit. [Figure 3] FIG. 3 is a perspective view showing the structure of the tip of the spindle. [Figure 4] FIG. 4 is a schematic structural diagram showing the structure of a detection unit according to an embodiment of the present invention. [Figure 5] FIG. 5 is a diagram illustrating the chipping patterns of a thin blade and a thick blade. [Figure 6] FIG. 6 is a diagram illustrating the detection unit of the blade breakage detection device. [Figure 7] FIG. 7 is a functional block diagram of a control unit that controls the operation of the blade breakage detection device. [Figure 8] FIG. 8 is a diagram showing a light receiving voltage detected by the light receiving amount detection unit. [Figure 9] FIG. 9 is a diagram illustrating another example of the detection unit of the blade breakage detection device. [Figure 10] FIG. 10 is a diagram illustrating the detection unit of the blade breakage detection device. [Figure 11] FIG. 11 is a diagram illustrating the detection unit of the blade breakage detection device. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a blade breakage detection device according to the present invention will now be described with reference to the accompanying drawings.

[0021] FIG. 1 is a perspective view showing the appearance of a dicing machine equipped with a blade breakage detection device 10 of the present invention.

[0022] The dicing apparatus 100 includes a processing unit 110 having a pair of spindles 106, 106 arranged opposite to each other, and a work table 108 that suction-cleanes the workpiece W. The dicing apparatus 100 also includes a cleaning unit 112 that spin-cleans the processed workpiece W, a load port 114 on which a cassette containing a plurality of workpieces W is placed, a transport device 116 that transports the workpiece W, and a control unit 118 that controls the overall operation of each unit.

[0023] The spindle 106 is, for example, a spindle with a built-in high-frequency motor, and a blade 102 for cutting a workpiece W is attached to the tip of the spindle 106. The blade 102 is rotated by the spindle 106 at a high speed of, for example, 8000 rpm to 60000 rpm.

[0024] The blade 102 is a cutting blade formed in a disk shape. As the blade 102, an electroplated blade in which diamond abrasive grains or CBN (Cubic Boron Nitride) abrasive grains are electrodeposited with nickel, or a resin blade in which the abrasive grains are bonded with resin, etc., is used. The thickness of the blade 102 is a thick blade having a thickness of 1 mm to 5 mm. The diameter of the blade 102 is, for example, 50 mm.

[0025] FIG. 2 is a perspective view showing the configuration of the processing unit 110. As shown in FIG.

[0026] The processing unit 110 shown in Fig. 2 has an X table 126. This X table 126 is guided by an X guide 122 provided on an X base 120, and is driven in the X-axis direction indicated by XX in Fig. 2 by a linear motor 124. A rotary table 128 that rotates about the Z axis is mounted on this X table 126, and the work table 108 is mounted on this rotary table 128.

[0027] The processing unit 110 also has a Y base 130. This Y base 130 is disposed so as to straddle the linear motor 124. A Y table 134 is provided on the side of the Y base 130, guided by a Y guide 132 and driven in the Y-axis direction indicated by YY in FIG. 2 by a drive unit (not shown). Each Y table 134 is provided with a Z table 136 that is driven in the Z-axis direction by a drive unit (not shown). The spindle 106, to which the blade 102 is attached at its tip, is fixed to the Z table 136. With this structure of the processing unit 110, the blade 102 is indexed in the Y-axis direction and cut in the Z-axis direction, and the work table 108 is cut in the X-axis direction. The X, Y, and Z axes are mutually orthogonal, with the X and Y axes oriented horizontally and the Z axis oriented vertically (up and down).

[0028] FIG. 3 is a perspective view showing the structure of the tip end of the spindle 106.

[0029] 3, a wheel cover 15 that covers the top of the blade 102 is attached to the tip of the spindle 106. This wheel cover 15 is constructed by assembling members such as a front cover portion 16, a rear cover portion 18, and a nozzle block 20, and has the function of suppressing the scattering of cutting powder, cutting water, and cooling water that are generated when the workpiece W is machined.

[0030] An end of a hose 21 is connected to the upper surface of the rear cover portion 18, and cutting water is supplied from the hose 21. The supplied cutting water is sprayed toward the rotating blade 102 from a nozzle 23 provided on the wheel cover 15. In addition, an end of a hose 22 is connected to the upper surface of the nozzle block 20, and cooling water is supplied from the hose 22. The supplied cooling water is sprayed toward the rotating blade 102 and workpiece W from a pair of L-shaped nozzles 24, 24 arranged opposite each other with the blade 102 in between.

[0031] The wheel cover 15 configured as described above is provided with the detection unit 12 that constitutes the blade breakage detection device 10, and a feed mechanism 14 that moves the detection unit 12 in the Z-axis direction. The blade breakage detection device 10 is composed of the detection unit 12 and a control unit 118 (see FIGS. 1 and 7).

[0032] Next, a detailed description will be given of the structure of the detection unit 12. In the following description, first, an embodiment that is a prerequisite for explaining the present invention will be explained with reference to Fig. 4, and then the present invention will be explained.

[0033] Fig. 4 is a diagram showing an example of the detection unit 12 according to the embodiment of the present invention, and is a schematic structural diagram showing the structure of the detection unit 12. Fig. 4 shows a schematic structural diagram of the detection unit 12 as viewed from the X-axis direction in Fig. 3.

[0034] As shown in Fig. 4, the detection unit 12 is composed of a light-projecting section 26 and a light-receiving section 28. In the example shown in Fig. 4, the light-projecting section 26 and the light-receiving section 28 are integrally formed by the detection unit main body 12A above the Z axis of the blade 102, and the light-projecting surface 36 and the light-receiving surface 44 are disposed opposite each other with the blade 102 sandwiched therebetween.

[0035] The light projecting unit 26 has a light emitting element 30 configured as a light emitting diode, a laser diode, or the like, an optical cable 32 that transmits light from the light emitting element 30, a light projecting optical path section 26A through which the light emitted from the optical cable 32 passes, and a right-angle prism 34 attached to the lower part of the light projecting optical path section 26A that reflects and emits the light transmitted by the light projecting optical path section 26A. The light exit end face of the right-angle prism 34 is formed as a light projecting surface 36 of the light projecting unit 26. The light projecting surface 36 is disposed at a distance from the side surface of the blade 102.

[0036] The light receiving unit 28 has a light receiving element 38 such as a photodiode, an optical cable 40 connected to the light receiving element 38, a light receiving optical path section 28A through which light incident from the right-angle prism 42 passes, and the right-angle prism 42 attached to the lower part of the light receiving optical path section 28A and connected to the optical cable 40. The light incident end face of the right-angle prism 42 is formed as a light receiving surface 44 of the light receiving unit 28. The light receiving surface 44 is disposed at a distance from the side surface of the blade 102.

[0037] The light-projecting surface 36 and the light-receiving surface 44 are disposed opposite each other with the outer circumferential portion 102R, which is the cutting edge of the blade 102, in between. The light is emitted from the light-projecting surface 36 toward the light-receiving surface 44, and that light that is not blocked by the outer circumferential portion 102R is incident on the light-receiving surface 44. The light that is incident on the light-receiving surface 44 is received by the light-receiving element 38. The control unit 118 (see FIG. 1), which will be described later, detects damage to the blade 102 based on the amount of light received by the light-receiving element 38.

[0038] 4, in the embodiment that is the premise of the present invention, the detection unit 12 is installed so that the optical axis portion La between the light-projecting surface 36 and the light-receiving surface 44 of the optical axis L is parallel to the rotation axis C of the blade 102. In other words, the optical axis L of the light irradiated onto the outer periphery 102R of the blade 102 is parallel to the rotation axis C of the blade 102, and the light emitted from the light-projecting surface 36 is irradiated towards the outer periphery 102R of the blade 102 in a direction parallel to the rotation axis C of the blade 102.

[0039] Here, the problems in the embodiment that is the premise of the present invention will be described.

[0040] Figure 5 is a diagram illustrating the form of chipping in thin and thick blades. Note that Figure 5 shows a simplified illustration of the light-emitting unit 26 and the light-receiving unit 28 that make up the detection unit 12. Also, to make the invention easier to understand, the thickness of each blade is exaggerated.

[0041] In Fig. 5, reference numeral 202 indicates a schematic diagram showing chipping of the thin blade 210, and reference numeral 204 indicates a schematic diagram showing chipping of the thick blade 102. In both reference numerals 202 and 204, the optical axis L of the detection unit 12 (corresponding to the optical axis portion La between the light-projecting surface 36 and the light-receiving surface 44 in Fig. 4) is parallel to the rotation axis C of the blade 210. The light R emitted from the light-projecting unit 26 is a beam-like light having a diameter of 1 mm to 2 mm.

[0042] As indicated by the reference numeral 202, when a chip Q1 occurs in the thin blade 210, the light R emitted from the light-emitting unit 26 passes through the chip Q1 of the blade 210 without being blocked by the blade 210 during one rotation of the blade 210, and is received by the light-receiving unit 28. Therefore, when the chip Q1 exists in the blade 210, a peak M (see FIG. 7) is detected in the amount of light received by the light-receiving unit 28 by rotating the blade 210. This allows the blade breakage detection device 10 to detect the chip Q1.

[0043] On the other hand, reference numeral 204 shows a case where a chip Q2 has occurred on the outer periphery 102R of the thick blade 102. The chip Q2 has occurred only on the first surface 102a side of the outer periphery 102R of the blade 102. In such a case, even if light R emitted from the light-projecting unit 26 is directed at the location where the chip Q2 has occurred, it is blocked by the second surface 102b (the back surface of the first surface) of the blade 102 and is not received by the light-receiving unit 28. Therefore, even if chip Q2 exists on the blade 102, the light-receiving unit 28 cannot receive the light R emitted from the light-projecting unit 26, even at the position where chip Q2 exists, and therefore the peak M cannot be detected in the amount of light received by the light-receiving unit 28.

[0044] In a thick blade 102, a chip Q2 may occur only on the first surface 102a or the second surface 102b, but as shown in Figure 5, the chip Q2 cannot be detected even if light parallel to the rotation axis C of the blade 102 is irradiated onto the outer periphery 102R of the blade 102. Therefore, in the embodiments (first and second embodiments) of the present invention described below, it is possible to detect a chip Q2 that has occurred on only one surface (the first surface 102a or the second surface 102b) of the outer periphery 102R of a thick blade 102.

[0045] First Embodiment A first embodiment of the blade breakage detection device 10 of the present invention will be described. The following description will focus on differences from the embodiment on which the present invention is based (particularly the detection unit 12 described in FIG. 4).

[0046] Fig. 6 is a diagram illustrating the detection unit 12 of the blade breakage detection device 10. Note that Fig. 6 shows the light-projecting unit 26 and the light-receiving unit 28 in a simplified form, similar to Fig. 5, and the light R emitted from the light-projecting unit 26 is a beam of light with a diameter φ of 1 to 2 mm. Furthermore, the light-projecting unit 26 described below is the light irradiating means of the present invention, and the light-receiving unit 28 is the light-receiving means of the present invention.

[0047] As shown in FIG. 6, in the detection unit 12 of the first embodiment, the optical axis L of the light R irradiated onto the outer periphery 102R of the blade 102 is inclined obliquely with respect to the rotation axis C of the blade 102. That is, the light R emitted from the light-projecting unit 26 is irradiated toward the outer periphery 102R of the blade 102 in a direction oblique to the rotation axis C of the blade 102. By irradiating the outer periphery 102R of the blade 102 with the light R having the optical axis L inclined obliquely with respect to the rotation axis C of the blade 102 from the light-projecting unit 26 in this manner, the light is received by the light-receiving unit 28 at the location of the chip Q2 without being blocked by the blade 102. This allows the blade breakage detection device 10 to detect the chip Q2 that has occurred on only one surface (first surface 102a) of the outer periphery 102R of the blade 102.

[0048] Here, the inclination angle α of the optical axis L with respect to the rotation axis C is preferably in the range of 30 to 60 degrees. The inclination angle α refers to the inclination angle of the optical axis L (corresponding to the optical axis portion La between the light-projecting surface 36 and the light-receiving surface 44 in FIG. 4) with respect to the rotation axis C when the blade 102 is viewed from the X-axis direction as shown in FIG. 4. By setting the inclination angle α within this range, the chip Q2 can be detected with high sensitivity without the light R being blocked by the blade 102. Furthermore, by setting the inclination angle α to approximately 45 degrees, the chip Q2 can be detected with even higher sensitivity. Here, the optical axis L refers to the optical axis that indicates the optical path of the light R from the light-projecting surface 36 of the light-projecting unit 26 (see FIG. 4) to the light-receiving surface 44 of the light-receiving unit 28 (see FIG. 4).

[0049] Fig. 7 is a functional block diagram of the control unit 118 that controls the operation of the blade breakage detection device 10. Note that the control unit 118 controls the entire dicing device 100, but Fig. 7 only shows the functional unit that controls the operation of the blade breakage detection device 10.

[0050] The control unit 118 includes a light-receiving amount detection unit 62 that detects the amount of light received by the light-receiving element 38 (see FIG. 4) per unit time, and a damage detection unit 64 that detects damage to the blade 102 based on the detection result of the light-receiving amount detection unit 62. The control unit 118 is configured to include one or more processors, including a CPU (Central Processing Unit) and an FPGA (Field-Programmable Gate Array), and one or more memories. The control unit 118 corresponds to the detection means of the present invention.

[0051] FIG. 8 is a diagram showing the received light voltage detected by the received light amount detector 62. As shown in FIG.

[0052] FIG. 8 shows the light-receiving voltage when the detection unit 12 shown in FIG. 6 receives light that has passed through the notch Q2.

[0053] When the blade 102 rotates at a predetermined cycle, a peak M of the light-receiving voltage caused by light passing through the chipping Q2 and received by the light-receiving unit 28 can be periodically obtained. The light-receiving element 38 constituting the light-receiving unit 28 outputs a light-receiving voltage corresponding to the amount of light received. The breakage detection unit 64 then detects this periodically obtained peak M to detect breakage (chip Q2) in the blade 102. Therefore, the blade breakage detection device 10 can automatically detect chipping Q2 in the blade 102 by having the received light amount detection unit 62 output a light-receiving result, which is a light-receiving voltage corresponding to the amount of light received, and having the breakage detection unit 64 detect the peak M.

[0054] As described above, in the detection unit 12 of the blade breakage detection device 10 of this embodiment, the optical axis L of the light R irradiated onto the outer periphery 102R of the blade 102 is configured to be inclined obliquely with respect to the rotation axis C of the blade 102, so that chips that have occurred on only one side of the outer periphery 102R of the blade 102 can be detected.

[0055] Note that, in the above description, a case where chipping Q2 occurring in the outer periphery 102R on the first surface 102a side of the blade 102 is detected has been described as an example, but the aspect of this embodiment is not limited thereto. For example, as shown in FIG. 9, to detect chipping Q2 occurring in the outer periphery 102R on the second surface 102b side, the direction in which the optical axis L of the light R irradiated onto the outer periphery 102R of the blade 102 is inclined obliquely with respect to the rotation axis C of the blade 102 may be reversed from the configuration shown in FIG. 6. That is, the distance between the light-projecting unit 26 and the rotation axis C may be made shorter than the distance between the light-receiving unit 28 and the rotation axis C (in other words, the light-projecting unit 26 may be brought closer to the rotation axis C than the light-receiving unit 28), so that the light R irradiated from the light-projecting unit 26 toward the chipping Q2 on the first surface 102a side of the blade 102 can be received by the light-receiving unit 28.

[0056] Furthermore, since there is a certain tendency for the surface (first surface 102a or second surface 102b) on which chipping Q2 is likely to occur on the outer periphery 102R of the blade 102 to depend on the manner in which the blade 102 is used, for example, two types of detection units (a detection unit corresponding to the configuration shown in Figure 6 and a detection unit corresponding to the configuration shown in Figure 9) in which the inclination of the optical axis L of the light R irradiated onto the outer periphery 102R of the blade 102 is different from each other may be provided, or these functions may be realized by a single detection unit.

[0057] The embodiment is not particularly limited as long as it has the function of irradiating the outer peripheral portion 102R of the blade 102 with light having an optical axis L inclined obliquely with respect to the rotation axis C of the blade 102. For example, the detection unit 12 may be realized by arranging the light-emitting element 30 and the light-receiving element 38 at any position and combining a reflecting member such as a mirror or prism for guiding light from the light-emitting element 30 to the light-receiving element 38. Furthermore, the detection unit 12 shown in FIG. 4 may be realized by tilting it about the X-axis direction.

[0058] Furthermore, the blade breakage detection device 10 may be equipped with, for example, a tilting mechanism that can change the tilt angle of the detection unit 12, and when a user selects any of the three detection modes (1) normal mode (the optical axis is parallel to the blade rotation axis), (2) first surface chipping detection mode (corresponding to Figure 6), or (3) second surface chipping detection mode (corresponding to Figure 9) via an operation unit (not shown), the control unit 118 may change the tilt angle α of the detection unit 12 to an angle corresponding to the selected mode and perform damage detection.

[0059] <Second embodiment> Next, a second embodiment will be described. In the first embodiment described above, the optical axis L of the light R irradiated onto the outer periphery 102R of the blade 102 is configured to be inclined obliquely with respect to the rotation axis C of the blade 102. In contrast, in the second embodiment, a pair of lenses (light-projecting unit-side lens 50 and light-receiving unit-side lens 52 (see FIGS. 10 and 11)) with a high numerical aperture (NA) are used to enable detection of chips occurring on only one surface of the outer periphery 102R of the blade 102.

[0060] 10 and 11 are diagrams illustrating the detection unit 12 of the blade breakage detection device 10 according to the second embodiment. Note that the same reference numerals are used to denote the same parts as those described in FIGS. 5 and 6, and the description thereof will be omitted.

[0061] As shown in FIGS. 10 and 11 , the light-projecting unit 26 has a light-projecting unit-side lens 50, and the light-receiving unit 28 has a light-receiving unit-side lens 52. The light-projecting unit-side lens 50 corresponds to the first lens of the present invention, and the light-receiving unit-side lens 52 corresponds to the second lens of the present invention. The light-irradiating means of the present invention includes the light-projecting unit-side lens 50, and is configured to emit light from the light-emitting element 30 (see FIG. 4 ) through the light-projecting unit-side lens 50, optionally in combination with a reflective member (not shown) such as a mirror or a prism or other optical member. The light-receiving means of the present invention includes the light-receiving unit-side lens 52, and is configured to receive light incident from the light-receiving unit-side lens 52, optionally in combination with a reflective member (not shown) such as a mirror or a prism or other optical member, so that the light incident from the light-receiving unit-side lens 52 is received by the light-receiving element 38 (see FIG. 4 ). The light-projecting unit-side lens 50 and the light-receiving unit-side lens 52 have the same lens optical axis S (coincident with the optical axis L of the detection unit 12), and the lens optical axis S is arranged parallel to the rotation axis C of the blade 102. The light-projecting unit-side lens 50 and the light-receiving unit-side lens 52 are composed of lenses with a high numerical aperture NA. The light-projecting unit-side lens 50 and the light-receiving unit-side lens 52 are arranged to face each other, sandwiching the outer periphery 102R of the blade 102. The focal positions of the light-projecting unit-side lens 50 and the light-receiving unit-side lens 52 are located at the center Ra of the blade 102 in the width direction.

[0062] 10, when no chip Q2 occurs in the blade 102, of the light incident on the light-projecting unit-side lens 50, the light that passes through the outer periphery of the light-projecting unit-side lens 50 (the upper and lower parts of the lens in FIG. 10) is blocked by the first surface 102a and the second surface 102b of the blade 102. On the other hand, light R that passes through the center of the light-projecting unit-side lens 50 (indicated by the arrow in FIG. 10) is incident on the light-receiving unit-side lens 52 and detected by the light-receiving unit 28.

[0063] 11, when there is a notch Q2 in the blade 102, of the light incident on the light-projection-unit-side lens 50, light R that passes through a part of the outer periphery of the light-projection-unit-side lens 50 (the lower side of the lens in FIG. 11) is blocked by the blade 102. On the other hand, light R that passes through a part of the outer periphery of the light-projection-unit-side lens 50 (the upper side of the lens in FIG. 11) is not blocked by the notch Q2 in the blade 102, and is detected by the light-receiving unit 28 together with light that has passed through the center of the blade 102.

[0064] Therefore, the amount of light detected by the light receiving unit 28 changes depending on whether or not there is a chip Q2 in the blade 102, and the detection results make it possible to detect the chip Q2 (breakage) in the blade 102. Note that the fact that the chip Q2 is detected by the change in the amount of light detected by the light receiving unit 28 has already been explained with reference to Figures 7 and 8, so a detailed explanation will be omitted here.

[0065] Furthermore, when chipping occurs on both sides (first surface 102a and second surface 102b) of blade 102, light R that passes through a part of the outer periphery of light-emitter-side lens 50 (the upper and lower sides of the lens in FIG. 11) is detected by light-receiving unit 28 without being blocked by blade 102. Therefore, in this case, the amount of light detected by light-receiving unit 28 is the greatest, so chipping can be detected even when chipping occurs on both sides of blade 102, not just one side.

[0066] It is preferable that the numerical aperture NA of the light-projecting unit-side lens 50 and the light-receiving unit-side lens 52 is, for example, 0.4 or greater. If the numerical aperture NA of the light-projecting unit-side lens 50 and the light-receiving unit-side lens 52 is 0.4 or greater, the amount of light detected by the light-receiving unit 28 changes depending on the occurrence of chipping Q2 in the outer periphery 102R of the blade 102, making it possible to detect chipping Q2 with high accuracy.

[0067] Also, as an example, in Figure 11, if the thickness of blade 102 is 3 mm, the distance between blade 102 and light-projecting unit side lens 50 and light-receiving unit side lens 52 is 2.25 mm, the lens thickness of light-projecting unit side lens 50 and light-receiving unit side lens 52 is 2.5 mm, the focal length of light-projecting unit side lens 50 and light-receiving unit side lens 52 is 5 mm, the lens diameter of light-projecting unit side lens 50 and light-receiving unit side lens 52 is 5 mm, and the numerical aperture NA is 0.45, even a chip Q2 of 1 mm or less that occurs in blade 102 can be detected.

[0068] As described above, in the detection unit 12 of the blade breakage detection device 10 of the second embodiment, the pair of light-projection unit-side lenses 50 and light-receiving unit-side lenses 52, each having a high numerical aperture NA, are arranged at positions facing each other across the outer periphery 102R of the blade 102, and the lens optical axes S of the pair of light-projection unit-side lenses 50 and light-receiving unit-side lenses 52 are arranged parallel to the rotation axis C of the blade 102. As a result, even if a chip Q2 occurs on only one surface (the first surface 102a or the second surface 102b) of the outer periphery 102R of the blade 102, the light R irradiated onto the outer periphery 102R of the blade 102 via the pair of light-projection unit-side lenses 50 and light-receiving unit-side lenses 52, each having a high numerical aperture NA, is received by the light-receiving unit 28, and the amount of light detected by the light-receiving unit 28 changes depending on the occurrence of the chip Q2 on the outer periphery 102R of the blade 102. Therefore, according to the second embodiment, similarly to the first embodiment, it is possible to detect chipping that occurs on only one side of the outer circumferential portion 102R of the blade 102. Moreover, it is also possible to detect not only chipping that occurs on only one side of the blade 102, but also chipping that occurs on both sides of the outer circumferential portion 102R of the blade 102.

[0069] Although examples of the present invention have been described above, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the present invention. [Explanation of symbols]

[0070] 10...Blade breakage detection device, 12...Detection unit, 14...Feed mechanism, 15...Wheel cover, 16...Front cover, 18...Rear cover, 20...Nozzle block, 21...Hose, 22...Hose, 23...Nozzle, 24...Nozzle, 26...Light-emitting section, 26A...Light-emitting optical path section, 28...Light-receiving section, 28A...Light-receiving optical path section, 30...Light-emitting element, 32...Optical cable, 34...Right-angle prism, 36...Light-emitting surface, 38...Light-receiving element, 40...Optical Culcable, 42...Right-angle prism, 44...Light-receiving surface, 50...Light-emitting unit side lens, 52...Light-receiving unit side lens, 62...Light-receiving amount detection unit, 64...Breakage detection unit, 100...Dicing device, 102...Blade, 102R...Outer periphery, 102a...First surface, 102b...Second surface, 106...Spindle, 108...Work table, 110...Processing unit, 112...Cleaning unit, 114...Load port, 116...Transport device, 118...Control unit, C...Rotation axis, L...Optical axis

Claims

1. 1. A blade breakage detection device for detecting breakage of a rotatable blade, comprising: a light irradiation means for irradiating the outer periphery of the blade with light that has passed through a first lens having an optical axis parallel to the rotation axis of the blade; a light receiving means that receives the light that has passed through a second lens that faces the first lens across the outer periphery of the blade and has the same optical axis as the first lens; a detection means for detecting damage to the blade based on the light received by the light receiving means; A blade breakage detection device comprising:

2. The numerical aperture NA of the first lens and the second lens is 0.4 or more. The blade breakage detection device according to claim 1 .

3. The focal positions of the first lens and the second lens are located at the center in the width direction of the blade. The blade breakage detection device according to claim 1 or 2.

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