Cutting apparatus

Abstract

To perform setup without bringing a contact terminal into physical contact with an outer peripheral portion or outer peripheral side surface of a bottom surface of a table base.SOLUTION: A cutting apparatus comprises: a chuck table which has a holding surface including a holding region and an outer peripheral region; a table base which supports the chuck table; a shaft having one end fixed to a central portion of a bottom surface of the table base; a rotation drive source which rotates the shaft; a terminal portion that can be electrically connected at another end portion of the shaft and permits rotation of the shaft; a cutting unit having a spindle disposed above the holding surface; and a power supply section which electrically connects the terminal portion and the spindle. When a cutting blade contacts the outer peripheral region of the chuck table, the cutting blade, the spindle, the power supply section, the terminal portion, the shaft, the table base, and the chuck table form a detection circuit, and the detection circuit detects electrical conduction between the outer peripheral region of the chuck table and the cutting blade.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a cutting device including a chuck table and a cutting unit. [Background technology]

[0002] Electronic devices such as mobile phones and PCs (Personal Computers) are equipped with device chips having devices such as ICs (Integrated Circuits). Device chips are manufactured, for example, by dividing a silicon wafer (i.e., a workpiece) on which a plurality of devices are regularly arranged on its surface into device units.

[0003] To divide the workpiece, for example, a cutting device is used, which includes a disk-shaped chuck table for suction-holding the workpiece, a cutting unit disposed above the chuck table, and a microscope camera unit for capturing images of the workpiece held by the chuck table.

[0004] The cutting unit has a cylindrical spindle. A cutting blade such as an electroplated blade is attached to the tip of the spindle (see, for example, Patent Document 1). When cutting a workpiece with a cutting device, the workpiece is generally first sucked and held on a chuck table so that the surface of the workpiece is exposed upward.

[0005] Next, the surface of the workpiece is imaged using a microscope camera unit, and based on the image obtained, the rotation angle of the chuck table around the rotation axis located at the radial center of the chuck table is adjusted to make the linear dividing line set on the surface of the workpiece approximately parallel to the movement direction of the chuck table (i.e., the processing feed direction).

[0006] Then, with the lower end of the cutting blade rotating at high speed around the spindle as its rotation axis positioned at a predetermined height between the holding surface of the chuck table and the surface of the workpiece, the chuck table is moved in the processing feed direction, causing the cutting blade to cut into the workpiece. In this way, the workpiece is cut along the intended dividing line.

[0007] In addition, the rotation angle of conventional chuck tables was limited to a predetermined range of less than 360 degrees, but in recent years, cutting devices have been developed that eliminate the range limit for the rotation angle of the chuck table in order to perform a wide variety of processing, measurements, etc. (see, for example, Patent Document 2).

[0008] During cutting, the cutting depth of the cutting blade into the workpiece is adjusted by adjusting the height position of the lower end of the cutting blade, and the reference position (i.e., the origin position in the height direction) when adjusting the cutting depth is determined using the height position of the holding surface of the chuck table.

[0009] When cutting a workpiece, the cutting blade wears and the diameter of the cutting blade becomes smaller, so an operation (called setup) to correct the origin position in the height direction for the cutting blade is periodically performed in the cutting device.

[0010] When performing setup, the cutting device gradually lowers the cutting unit toward the chuck table until the lower end of the cutting blade comes into contact with the metal frame that constitutes the chuck table.

[0011] The height position of the cutting unit when a current flows through a detection circuit including an electrically connected frame, cutting blade, etc. is used as the origin position of the cutting blade relative to the holding surface. For example, if the lower end of the cutting blade is to be raised 1 μm from the holding surface, the cutting unit is raised 1 μm when the cutting blade is at the origin position.

[0012] In the cutting device described in the above-mentioned Patent Document 2, a brush assembly having a carbon brush (i.e., contact terminal) is provided below a metal table base that supports the chuck table. The carbon brush is configured to be able to come into contact with the outer periphery of the bottom surface of the table base.

[0013] During setup, the cutting device gradually lowers the cutting unit toward the chuck table and detects the height position of the cutting unit when current flows through a detection circuit including the cutting blade, chuck table frame, table base, brush assembly, etc.

[0014] However, if there is insufficient space directly below the outer periphery of the bottom surface of the table base, it may not be possible to install a brush assembly. Also, while it is possible to have carbon brushes in contact with the outer side surface of the table base, there is a risk that the carbon brushes may interfere with clamp units and other devices that hold the ring frame that supports the workpiece via the dicing tape. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-87282 [Patent Document 2] Japanese Patent Publication No. 2022-14182 Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention has been made in consideration of the above problems, and aims to perform setup without physically contacting the contact terminals with the outer periphery of the bottom surface of the table base or the outer side surface of the table base. [Means for solving the problem]

[0017] According to one aspect of the present invention, there is provided a chuck table having a holding surface including a holding area for suction-holding a workpiece and a metallic outer peripheral area located outside the holding area, a table base supporting the chuck table and electrically connected to the outer peripheral area, a shaft electrically connected to the outer peripheral area via the table base and having one longitudinal end fixed to the center of the bottom surface of the table base, a rotational drive source having a motor for rotating the shaft, and a terminal portion contacting the other longitudinal end of the shaft to be electrically connected to the shaft and allowing the shaft to rotate. a cutting unit having a spindle disposed above the holding surface, with a conductive cutting blade attached to the tip of the spindle in a manner that electrically connects the cutting blade; and a power supply unit electrically connected to the terminal unit and the spindle, wherein when the cutting blade attached to the tip of the spindle comes into contact with the outer peripheral region of the chuck table, the cutting blade, spindle, power supply unit, terminal unit, shaft, table base, and chuck table form a detection circuit, and the detection circuit detects electrical continuity between the outer peripheral region of the chuck table and the cutting blade.

[0018] Preferably, the terminal portion has a ball plunger, and a metal ball in the ball plunger is pressed against the other end of the shaft while being biased by a spring. [Effects of the Invention]

[0019] In a cutting device according to one aspect of the present invention, a chuck table is supported by a table base. One longitudinal end of a shaft is fixed to the center of the bottom surface of the table base. A terminal portion is in contact with the other longitudinal end of the shaft in a manner that allows rotation of the shaft.

[0020] When the cutting blade attached to the tip of the spindle comes into contact with the outer periphery of the chuck table, the cutting blade, spindle, power supply, terminal, shaft, table base, and chuck table form a detection circuit, so that the detection circuit for setup can be configured without physically contacting the contact terminal with the outer periphery of the bottom surface of the table base or the outer periphery of the table base. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. [Figure 2] FIG. 2 is a partial cross-sectional side view of a chuck table, a table base, and a rotary drive source. [Figure 3] 3 is an enlarged view of the lower end of the shaft indicated by the dashed square line in FIG. 2. [Figure 4] FIG. 2 is a diagram illustrating a detection circuit. DETAILED DESCRIPTION OF THE INVENTION

[0022] An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view of a cutting device 2. The X-axis, Y-axis, and Z-axis shown in Fig. 1 are perpendicular to one another. The X-axis is approximately parallel to the processing feed direction, the Y-axis is approximately parallel to the indexing feed direction, and the Z-axis is approximately parallel to the height direction (vertical direction).

[0023] The cutting device 2 includes a base 4 that supports each of the components. An opening 4a is provided at the front corner of the base 4. A cassette elevator 6a that moves up and down by an elevator mechanism (not shown) is provided within the opening 4a. Note that FIG. 1 shows the approximate position of the cassette elevator 6a, but does not show the cassette elevator 6a itself.

[0024] On the upper surface of the cassette elevator 6a, a cassette 6b is placed for accommodating a plurality of workpieces 11. The workpieces 11 include, for example, wafers having a disk-shaped single crystal silicon substrate.

[0025] The surface of the workpiece 11 is divided into a plurality of regions by a plurality of straight dividing lines (streets) that intersect with each other, and a device such as an IC (Integrated Circuit) is formed in each region.

[0026] A dicing tape 13 having a larger diameter than the workpiece 11 is attached to the back surface of the workpiece 11. The outer periphery of the dicing tape 13 is attached to a ring frame 15 made of metal such as stainless steel. The workpiece 11 is housed in the cassette 6b in the form of a workpiece unit 17 supported by the ring frame 15 via the dicing tape 13.

[0027] An opening 4b is formed on the side of the cassette elevator 6a. The long side of the opening 4b is arranged along the X-axis. A cover member 12 (i.e., a rectangular first cover member 12a and a bellows-shaped second cover member 12b) is provided inside the opening 4b.

[0028] An X-axis direction moving mechanism 10 is disposed below the cover member 12. Note that Fig. 1 shows the approximate position of the X-axis direction moving mechanism 10, but does not show the X-axis direction moving mechanism 10 itself. The X-axis direction moving mechanism 10 has an X-axis direction moving plate 52 (see Fig. 2).

[0029] The X-axis direction moving plate 52 is fixed to be slidable relative to a pair of guide rails (not shown) arranged along the X-axis. A screw shaft (not shown) is provided between the pair of guide rails, with its longitudinal direction aligned with the X-axis.

[0030] A nut portion (not shown) is provided on the bottom surface of the X-axis direction moving plate 52. A plurality of balls (not shown) are provided inside the nut portion, and the above-mentioned screw shaft is rotatably coupled to the nut portion via the plurality of balls (not shown).

[0031] A drive source (not shown), such as a servo motor or a stepping motor, is provided at one end of the screw shaft. When the drive source rotates the screw shaft, the X-axis direction moving plate 52 moves along the X-axis. The chuck table 14, table base 20, rotation drive source 42, etc., shown in FIG. 2, are provided on the X-axis direction moving plate 52.

[0032] 2 is a partial cross-sectional side view of the chuck table 14, the table base 20, and the rotary drive source 42. The chuck table 14 has a disk-shaped metal frame 16. In this embodiment, the frame 16 is entirely made of metal to ensure rigidity and conductivity. The frame 16 is made of, for example, stainless steel.

[0033] However, as long as the frame body 16 can form a part of the detection circuit 102 (see Figure 4) described later, the frame body 16 does not have to be formed entirely from metal, and it is sufficient if a part of the frame body 16 is formed from a conductive material.

[0034] A disk-shaped recess 16a is formed in the radial center of the frame 16. A disk-shaped porous plate 18 made of porous ceramics is fixed to the recess 16a using an adhesive (not shown) or the like.

[0035] The top surface of the frame 16 and the top surface of the porous plate 18 function as a holding surface 14a that suction-holds the workpiece 11 via the dicing tape 13. The holding surface 14a is substantially flush and is disposed substantially parallel to the XY plane.

[0036] The holding surface 14a includes a circular holding area 14a1 corresponding to the top surface of the porous plate 18 to which the negative pressure is transmitted, and an annular outer peripheral area 14a2 located outside the holding area 14a1 and corresponding to the top surface of the frame body 16.

[0037] The bottom surface of the recess 16a is provided with a plurality of radial flow passages 16b, a central flow passage 16c, and a plurality of annular flow passages (not shown), which are connected to each other. The radial flow passages 16b are provided radially along the radial direction of the frame 16.

[0038] The multiple annular passages are arranged concentrically and connect the radial passages 16b to one another. The radial passages 16b connect to the upper end of the central passage 16c at the radial center of the frame 16. The lower end of the central passage 16c reaches the bottom surface of the frame 16.

[0039] An annular protrusion 16d is provided on the bottom surface of the frame 16 outside the lower end of the central flow path 16c. The annular protrusion 16d is used to position the chuck table 14 relative to the table base 20.

[0040] A plurality of cylindrical protrusions 16e are provided on the bottom surface of the frame 16 further outward than the annular protrusion 16d. Each of the protrusions 16e is also used to position the chuck table 14 relative to the table base 20.

[0041] The chuck table 14 is attached to the top surface of a disk-shaped table base 20. In this embodiment, the table base 20 is entirely made of metal to ensure rigidity and conductivity. The table base 20 is made of, for example, stainless steel.

[0042] However, as long as the table base 20 can form part of the detection circuit 102, the table base 20 does not have to be made entirely of metal, and it is sufficient if part of the table base 20 is made of a conductive material.

[0043] The top surface of the table base 20 is provided with an annular groove 20a into which the above-mentioned annular protrusion 16d is inserted, and a plurality of cylindrical recesses 20b arranged outside the annular groove 20a and into which one protrusion 16e is each inserted.

[0044] When the chuck table 14 is placed on the table base 20 so that the annular protrusion 16d is inserted into the annular groove 20a and the protrusion 16e is inserted into the corresponding cylindrical recess 20b, the chuck table 14 is supported on the top surface of the table base 20.

[0045] A suction port (not shown) through which negative pressure is transmitted is further provided on the top surface of the table base 20. When negative pressure is transmitted to the suction port on the top surface of the table base 20 while the chuck table 14 is supported by the table base 20, the chuck table 14 is held by suction on the table base 20.

[0046] A negative pressure is transmitted to the holding area 14a1 of the chuck table 14 and the suction port of the table base 20. This negative pressure is generated by a vacuum device (not shown) such as a vacuum pump or an ejector.

[0047] The vacuum device is mounted, for example, inside the base 4 of the cutting device 2, but may also be provided outside the base 4 independently of the cutting device 2. In either case, the negative pressure generated by the vacuum device is transmitted to the chuck table 14 and the table base 20 via a predetermined flow path (not shown).

[0048] Furthermore, as long as it has an annular protrusion 16d that is inserted into the annular groove 20a, a protrusion 16e that is inserted into the cylindrical recess 20b, and a flat surface that contacts the suction port on the top surface of the table base 20, any of multiple chuck tables 14 having different diameters can be attached to the table base 20.

[0049] A plurality of pairs of rods 22 are provided on the outer periphery of the table base 20, protruding outward in the radial direction of the table base 20 (see FIG. 1). In this embodiment, four pairs of rods 22 are arranged at approximately equal intervals in the circumferential direction of the table base 20.

[0050] A clamp unit 24 that clamps the ring frame 15 in the Z-axis direction is provided at the tip of each rod 22. As shown in Fig. 2, each clamp unit 24 includes a base portion 24a that supports the ring frame 15 and a pressing portion 24b that presses the ring frame 15 from above.

[0051] An air actuator (not shown) for moving the holding portion 24b is provided on the base portion 24a. By rotating the holding portion 24b relative to the base portion 24a using the air actuator, the tip of the holding portion 24b can be moved closer to the base portion 24a or moved away from the base portion 24a.

[0052] A central passage 20c is formed in the radial center of the table base 20, penetrating from the top surface to the bottom surface 20d of the table base 20. An upper end portion (i.e., one end portion) 26A in the longitudinal direction of a shaft 26 made of metal is fixed to the center of the bottom surface 20d of the table base 20. The table base 20 and the shaft 26 are arranged concentrically.

[0053] The shaft 26 is made of, for example, stainless steel. In this embodiment, the shaft 26 is made entirely of metal to ensure rigidity and conductivity. However, as long as the shaft 26 can form part of the detection circuit 102, the shaft 26 does not have to be made entirely of metal, and it is sufficient if only part of the shaft 26 is made of a conductive material.

[0054] The shaft 26 has a disk portion 26a at its upper end portion 26A. The top surface of the disk portion 26a is fixed in contact with the center of the bottom surface 20d of the table base 20, and the shaft 26 and the frame 16 (particularly, the outer peripheral region 14a2) are electrically connected via the table base 20.

[0055] A first cylindrical portion 26b having a smaller diameter than the disk portion 26a is connected to the bottom surface of the disk portion 26a. A central flow path 26c extending from the top surface of the disk portion 26a to a predetermined depth position in the first cylindrical portion 26b is provided in the radial center of the disk portion 26a and the first cylindrical portion 26b.

[0056] The shaft 26 constitutes the rotation axis of the rotary joint. A plurality of openings 26d, each connected to a central flow passage 26c, are provided on the outer peripheral side surface of the first cylindrical portion 26b. Each opening 26d is provided at a different position in the circumferential direction and the Z-axis direction of the first cylindrical portion 26b. Note that only one opening 26d is shown in FIG. 2.

[0057] The first cylindrical portion 26b includes large-diameter portions with relatively large diameters and small-diameter portions with relatively small diameters that are periodically and alternately arranged along the Z axis. A seal ring 26e made of resin or rubber is provided on the outer periphery of each large-diameter portion of the first cylindrical portion 26b.

[0058] One opening 26d is provided between two seal rings 26e adjacent to each other in the Z-axis direction. When negative pressure or positive pressure is transmitted to the central flow passage 26c, a fluid such as a gas flows through each opening 26d.

[0059] The negative pressure is transmitted from the vacuum device described above, while the positive pressure is transmitted from an air supply source (not shown). The air supply source includes a compressor that takes in air from the atmosphere, compresses it, and sends it out, and a tank that stores the compressed air.

[0060] A second cylindrical portion 26f, whose outer diameter is smaller than that of the first cylindrical portion 26b, is provided concentrically with the first cylindrical portion 26b at the bottom of the first cylindrical portion 26b. The top of the second cylindrical portion 26f is connected to the bottom of the first cylindrical portion 26b. A cylindrical recess is provided at the bottom of the second cylindrical portion 26f.

[0061] Fig. 3 is an enlarged view of the lower end portion 26B (i.e., the other end portion) in the longitudinal direction of the shaft 26, which is indicated by the dashed rectangular line in Fig. 2. A receiving portion 26g made of metal is fixed to the lower end portion 26B of the shaft 26.

[0062] The receiving portion 26g is made of, for example, stainless steel. The receiving portion 26g of this embodiment is a part of the shaft 26, has a shape similar to a rivet with a flat head, and includes a pin 26g1 and a disk portion 26g2.

[0063] The pin 26g1 of the receiving portion 26g is inserted into a recess in the second cylindrical portion 26f of the shaft 26, and the top surface of the disk portion 26g2 of the receiving portion 26g is located at the lower end of the second cylindrical portion 26f. The disk portion 26g2 of the receiving portion 26g comes into contact with the metal ball 28a that constitutes the ball plunger 28.

[0064] An annular recess 26g3 is formed on the bottom surface of the disk portion 26g2. In this embodiment, the annular recess 26g3 corresponds to approximately the upper half of the annular surface when the annular surface is cut in half along a plane perpendicular to the central axis of the annular surface. The upper end of the ball 28a is fitted into the annular recess 26g3.

[0065] Approximately the lower half of ball 28a is housed in ball housing portion 28b, which has a cylindrical space. Ball 28a is housed in ball housing portion 28b in a rotatable manner. Spring 28c is provided on the bottom surface of ball housing portion 28b, and spring 28c urges ball housing portion 28b upward.

[0066] The ball accommodating portion 28b and the spring 28c are housed in a cylindrical main body portion 28d. The upper half of the ball 28a protrudes from the main body portion 28d, and the ball 28a is pressed against the receiving portion 26g while being biased by the spring 28c. The ball 28a is constantly in contact with the receiving portion 26g, so that the ball plunger 28 can be electrically connected to the shaft 26.

[0067] Furthermore, because the ball 28a is rotatable, the ball plunger 28 allows the rotation of the shaft 26. No matter how much the shaft 26 rotates, the ball 28a can always contact the receiving portion 26g in the annular recess 26g3. Although a finite frictional resistance exists between the ball 28a and the receiving portion 26g, this frictional resistance is small enough not to significantly impede the rotation of the shaft 26.

[0068] The ball 28a, spring 28c, and ball receiving portion 28b are also entirely made of metal to ensure rigidity and conductivity, and are each made of, for example, stainless steel.

[0069] However, as long as ball 28a, spring 28c, and ball accommodating portion 28b can form part of detection circuit 102, spring 28c and ball accommodating portion 28b do not have to be formed entirely from metal, and it is sufficient if each part of ball 28a, spring 28c, and ball accommodating portion 28b is formed from a conductive material.

[0070] The lower end of spring 28c is electrically connected to a lead wire 96b (described later) via a connection terminal 30. Ball plunger 28, connection terminal 30, etc. form a terminal portion 32 that is electrically connected to shaft 26. Note that instead of making spring 28c a part of detection circuit 102, lead wire 96b may be connected to ball accommodating portion 28b.

[0071] A male thread is formed on the outer peripheral side surface of main body 28d of ball plunger 28, and main body 28d is fastened to a threaded hole provided in bracket 34. In addition to ball plunger 28, rotary joint housing 38 is also fixed to bracket 34 via fixing pin 36.

[0072] 2, a description will now be given of the rotary drive source 42 for rotating the shaft 26, the table base 20, and the chuck table 14. A bearing 40a is provided near the upper end 26A of the first cylindrical portion 26b of the shaft 26, and a bearing 40b is also provided near the lower end 26B of the first cylindrical portion 26b.

[0073] Housing 38 of the rotary joint is rotatably fixed to shaft 26 via bearings 40a and 40b. A disc-shaped connecting portion 44 is fixed to the bottom surface 20d of table base 20, outside of disc portion 26a of shaft 26.

[0074] A cylindrical rotor 46 is fixed to the bottom surface of the outer periphery of the connecting portion 44 using bolts 44a. The rotor 46 includes a rotor core 46a formed of a permanent magnet, a magnetic material, etc. A stator 48 having a coil, an iron core, etc. is provided in the space inside the rotor core 46a in a manner that does not make contact with the rotor 46.

[0075] The stator 48 is fixed to the X-axis direction moving plate 52 together with the bracket 34 using bolts 52a. The rotor 46, stator 48, etc. constitute a motor 50, and by supplying an appropriate current to the stator 48, the rotor 46 rotates integrally with the table base 20 and shaft 26.

[0076] That is, the rotary drive source 42 includes a motor 50, which rotates the shaft 26 together with the rotor 46. Returning to Fig. 1, other components of the cutting device 2 will now be described. The above-mentioned first cover member 12a is provided to cover the motor 50.

[0077] One end of second cover member 12b in the X-axis direction is fixed to first cover member 12a, and the other end of second cover member 12b in the X-axis direction is fixed to the edge of opening 4b. Second cover members 12b are provided on both sides of first cover member 12a in the X-axis direction, and expand and contract appropriately as first cover member 12a moves along the X-axis direction.

[0078] A cantilevered support structure 60 is provided in an area adjacent to the opening 4b in the Y-axis direction. A ball screw-type Y-axis and Z-axis movement mechanism 62 is provided on the front surface of the support structure 60. The Y-axis and Z-axis movement mechanism 62 has a pair of guide rails 64 fixed to the front surface of the support structure 60.

[0079] Each of the pair of guide rails 64 is arranged along the Y axis. A Y-axis direction moving plate 66 is slidably attached to the pair of guide rails 64. A screw shaft 68 is arranged between the pair of guide rails 64 along the Y axis.

[0080] The screw shaft 68 is rotatably coupled via a plurality of balls (not shown) to a nut portion (not shown) provided on the back surface of the Y-axis direction moving plate 66. A drive source (not shown) such as a pulse motor or a stepping motor is connected to one end of the screw shaft 68. When the drive source rotates the screw shaft 68, the Y-axis direction moving plate 66 moves along the Y-axis.

[0081] A pair of guide rails 70 are fixed to the front surface of the Y-axis direction moving plate 66. Each of the pair of guide rails 70 is arranged along the Z-axis. A Z-axis direction moving plate 72 is slidably attached to the pair of guide rails 70.

[0082] A screw shaft 74 is disposed along the Z axis between the pair of guide rails 70. The screw shaft 74 is rotatably coupled to a nut portion (not shown) provided on the back surface of the Z-axis direction moving plate 72 via a plurality of balls (not shown).

[0083] A drive source 76 such as a pulse motor or a stepping motor is connected to the upper end of the screw shaft 74. When the drive source 76 rotates the screw shaft 74, the Z-axis direction moving plate 72 moves along the Z axis. A cutting unit 80 is fixed to the lower end of the Z-axis direction moving plate 72. The cutting unit 80 has a spindle housing 82.

[0084] The spindle housing 82 is shaped like a square tube, with its longitudinal portion aligned along the Y axis. A cylindrical spindle 84 (see FIG. 4) is partially rotatably housed within the spindle housing 82. The longitudinal direction of the spindle 84 is aligned along the Y axis.

[0085] A motor (not shown) is provided inside the spindle housing 82, and operating this motor allows the spindle 84 to rotate at high speed. The spindle housing 82 and the spindle 84 are disposed above the holding surface 14a.

[0086] 4, a cutting blade 86 is attached to the tip of the spindle 84. The cutting blade 86 in this embodiment is a so-called washer blade (i.e., a hubless blade), and is composed only of a cutting edge containing abrasive grains, a bond material, etc.

[0087] The abrasive grains are, for example, diamond abrasive grains having electrical conductivity, but silica abrasive grains, cBN (cubic boron nitride) abrasive grains, etc. may also be used. The bond material is, for example, a metal bond or an electroformed bond, each of which has electrical conductivity.

[0088] However, when a conductive filler such as silver or a conductive powder such as carbon black is mixed in, a resin bond formed by sintering a thermosetting resin may be used. In any case, the cutting blade 86 is conductive.

[0089] The cutting blade 86 is clamped between a disk-shaped blade mount 88 fixed to the tip of the spindle 84 with a bolt or the like, and a disk-shaped pressing flange 92. The pressing flange 92 is pressed toward the blade mount 88 by a pressing nut 90 screwed onto the blade mount 88.

[0090] Alternatively, a hub blade, in which a cutting blade is formed by electrodeposition on one surface of a disk-shaped base (i.e., hub) made of a metal such as stainless steel, may be used as the cutting blade 86. In either case, the cutting blade 86 is electrically connected to the spindle 84 via a blade mount 88.

[0091] A contact terminal 94 made of a conductive material such as a carbon brush is provided at the rear end of the spindle 84, which is located on the opposite side of the cutting blade 86 in the Y-axis direction. The contact terminal 94 is pressed against the rear end of the spindle 84 by an elastic member such as a spring (not shown).

[0092] In this embodiment, the spring that presses the contact terminal 94 is made of a metal such as stainless steel, and one end of the lead wire 96a is connected to this spring. Note that one end of the lead wire 96a may be directly connected to the contact terminal 94 without using a spring as an electrical path.

[0093] The other end of the lead wire 96a is connected to the positive electrode of a DC power supply (power supply unit) 100 via an ammeter 98. The negative electrode of the DC power supply 100 is connected to the above-mentioned terminal unit 32 via a lead wire 96b.

[0094] The spindle 84, contact terminal 94, lead wire 96a, ammeter 98, DC power supply 100, lead wire 96b, terminal portion 32, shaft 26, table base 20 and chuck table 14 form a detection circuit 102 for detecting contact between the frame body 16 and the cutting blade 86.

[0095] 4 is a diagram showing the detection circuit 102. When the cutting blade 86 comes into contact with the outer peripheral region 14a2 of the chuck table 14, a current equal to or greater than a predetermined value flows in the ammeter 98. This allows the detection circuit 102 to detect electrical continuity between the outer peripheral region 14a2 and the cutting blade 86. Returning to FIG. 1 again, other components of the cutting device 2 will now be described.

[0096] A microscope camera unit 104 is provided at the lower end of the Z-axis direction moving plate 72 to capture images of the workpiece 11 during alignment, kerf checking, etc. An opening 4c is provided on the opposite side of the opening 4b to the opening 4a in the Y-axis direction.

[0097] A spinner cleaning unit 106 is provided in the opening 4c for cleaning, drying, etc. the workpiece 11 after cutting. The spinner cleaning unit 106 has a disk-shaped spinner table 106a that can rotate at high speed.

[0098] Above the spinner table 106a, there are provided a cleaning nozzle 106b for spraying pure water onto the workpiece 11 held on the spinner table 106a, and a drying nozzle 106c for spraying air to dry the workpiece 11 after cleaning.

[0099] The operation of the cutting device 2 is controlled by a controller (not shown). The controller is configured by a computer including, for example, a processor represented by a CPU (Central Processing Unit), a main storage device such as a DRAM (Dynamic Random Access Memory), and an auxiliary storage device such as a flash memory.

[0100] The auxiliary storage device stores software including a predetermined program. The functions of the controller are realized by operating the processor and other components in accordance with this software. During setup, the controller monitors the current value measured by the ammeter 98, and can determine when a current greater than a predetermined value flows through the ammeter 98.

[0101] Next, a method for setting up the cutting blade 86 will be described with reference to Fig. 4. When setting up, first, the cutting blade 86 is rotated. In this state, the Y-axis / Z-axis direction moving mechanism 62 is used to position the cutting unit 80 directly above the outer peripheral region 14a2 of the chuck table 14, and then the cutting unit 80 is lowered along the Z-axis direction at a predetermined speed.

[0102] When the lower end of the cutting blade 86 comes into contact with the outer peripheral region 14a2 of the chuck table 14, a current equal to or greater than a predetermined value flows in the ammeter 98. The controller uses the height position of the cutting unit 80 at the time when the current flows in the ammeter 98 as the origin position of the cutting blade 86 in the Z-axis direction relative to the holding surface 14a of the chuck table 14.

[0103] In the cutting device 2 of this embodiment, the chuck table 14 is supported by a table base 20, and an upper end 26A of a shaft 26 in the longitudinal direction is fixed to the center of a bottom surface 20d of the table base 20. A terminal portion 32 contacts a lower end 26B of the shaft 26 in the longitudinal direction in a manner that allows rotation of the shaft 26.

[0104] When the cutting blade 86 comes into contact with the outer peripheral region 14 a 2 of the chuck table 14 , the cutting blade 86 , the spindle 84 , the DC power supply 100 , the terminal portion 32 , the shaft 26 , the table base 20 and the chuck table 14 form a detection circuit 102 .

[0105] Therefore, the detection circuit 120 for performing setup can be configured without physically contacting contact terminals such as carbon brushes with the outer periphery of the bottom surface 20d of the table base 20 or the outer periphery side surface of the table base 20.

[0106] In addition, the structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the object of the present invention.

[0107] For example, instead of the chuck table 14 having the porous plate 18, a chuck table (a so-called universal chuck) made of a metal such as stainless steel and having multiple annular grooves arranged concentrically on the holding surface and each of which transmits negative pressure can be attached to the table base 20.

[0108] Furthermore, the terminal portion 32 in the above-described embodiment employs the ball plunger 28, but instead of this, a conductive member such as a carbon brush may be pressed toward the receiving portion 26g using the biasing force of a spring or the like.

[0109] Furthermore, the metal material used as the components of the detection circuit 102 is not limited to stainless steel. Other metal materials may be used as long as they satisfy both rigidity and electrical conductivity. Of course, a first material with relatively high rigidity and a second material with relatively high electrical conductivity may be used in combination.

[0110] Furthermore, instead of the ammeter 98, an electrical load having a relatively small predetermined resistance value, such as an LED (Light Emitting Diode), may be provided, and the controller may check whether or not there is continuity in the detection circuit 102 by receiving light emitted by the LED with a photoelectric conversion element.

[0111] Furthermore, the presence or absence of continuity in the detection circuit 102 may be determined by an operator, not necessarily by the controller. Specifically, the operator may check the continuity with the ammeter 98, the illumination of the LED, etc. [Explanation of symbols]

[0112] 2:Cutting device 4: Base, 4a, 4b, 4c: Opening 6a: Cassette elevator, 6b: Cassette 10:X-axis direction movement mechanism 11: Workpiece, 13: Dicing tape, 15: Ring frame 17: Workpiece unit 12: Cover member, 12a: First cover member, 12b: Second cover member 14: chuck table, 14a: holding surface, 14a1: holding area, 14a2: outer peripheral area 16: Frame body, 16a: Recessed portion, 16b: Radial flow passage, 16c: Central flow passage 16d: Annular protrusion, 16e: Protrusion 18: Porous board 20: Table base 20a: annular groove, 20b: cylindrical recess, 20c: central flow path, 20d: bottom surface 22: rod, 24: clamp unit, 24a: base portion, 24b: pressing portion 26: shaft, 26A: upper end (one end), 26B: lower end (the other end) 26a: disk portion, 26b: first cylindrical portion, 26c: central flow path, 26d: opening 26e: Seal ring, 26f: Second cylindrical part 26g: Receiving part, 26g1: Pin, 26g2: Disk part, 26g3: Annular recess 28: Ball plunger 28a: ball, 28b: ball receiving portion, 28c: spring, 28d: main body portion 30: Connection terminal 32:Terminal section 34: Bracket, 36: Fixing pin 38: Housing 40a, 40b: Bearings 42: Rotation drive source 44: Connection part, 44a: Bolt 46: rotor, 46a: rotor core, 48: stator, 50: motor 52: X-axis direction moving plate, 52a: bolt 60:Support structure 62:Y-axis and Z-axis direction movement mechanism 64: Guide rail, 66: Y-axis direction moving plate, 68: Screw shaft 70: Guide rail, 72: Z-axis direction moving plate, 74: Screw shaft, 76: Drive source 80: Cutting unit 82: Spindle housing, 84: Spindle, 86: Cutting blade 88: Blade mount, 90: Retaining nut, 92: Retaining flange 94: Contact terminal, 96a, 96b: Lead wires 98: Ammeter, 100: DC power supply (power supply section), 102: Detection circuit 104: Microscope camera unit 106: Spinner cleaning unit, 106a: Spinner table 106b: cleaning nozzle, 106c: drying nozzle

Claims

1. a chuck table having a holding surface including a holding area for suction-holding the workpiece and a metal outer peripheral area located outside the holding area; a table base supporting the chuck table and electrically connected to the outer peripheral region; a shaft electrically connected to the outer peripheral region via the table base, one end of which in the longitudinal direction is fixed to the center of the bottom surface of the table base; a rotary drive source having a motor for rotating the shaft; a terminal portion that can be electrically connected to the shaft by contacting the shaft at the other end in the longitudinal direction of the shaft and allows the shaft to rotate; a cutting unit having a spindle disposed above the holding surface, the cutting blade being electrically connected to a tip of the spindle; a power supply unit electrically connected to the terminal unit and the spindle; Equipped with A cutting device characterized in that when the cutting blade attached to the tip of the spindle comes into contact with the outer peripheral region of the chuck table, the cutting blade, the spindle, the power supply unit, the terminal unit, the shaft, the table base and the chuck table form a detection circuit, and the detection circuit detects electrical continuity between the outer peripheral region of the chuck table and the cutting blade.

2. The terminal portion has a ball plunger, 2. The cutting device according to claim 1, wherein the metal ball of the ball plunger is pressed against the other end of the shaft while being biased by a spring.

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