JP5798014B2 - Grinding equipment - Google Patents

Description

  The present invention relates to a grinding apparatus, for example, a grinding apparatus that grinds a workpiece with ultrasonic vibration.

  In a manufacturing process of various devices such as a mobile phone and a personal computer, a substantially disk-shaped wafer provided with an integrated circuit (IC) such as an LSI (Large Scale Integration) is used. The wafer is partitioned into a plurality of regions by division lines arranged in a lattice pattern on the surface, and an integrated circuit is formed in each of the partitioned regions. And each device used for various apparatuses is manufactured by cut | disconnecting a wafer along a division | segmentation planned line. Before the wafer is divided into individual devices, the back surface is ground and adjusted to a desired thickness by a grinding apparatus having a grinding wheel having a grinding wheel.

  By the way, when the back surface of a wafer is ground by a grinding apparatus, clogging may occur in the grinding wheel due to grinding waste generated along with grinding. In particular, when a brittle hard material such as sapphire, silicon nitride, lithium tantalate, or altic is ground, the grinding wheel is likely to be clogged, and it takes a long time to grind and the productivity may decrease. Focusing on these problems, the present applicant suppresses clogging of the grinding wheel due to grinding debris by arranging an annular ultrasonic vibrator on the grinding wheel and ultrasonically vibrating the grinding wheel during grinding. A grinding device that can be used has been developed and a patent application has been filed (see Patent Document 1).

  In such a grinding apparatus, power supply means for supplying power to the ultrasonic vibrator is connected to an end of a rotating spindle coupled to a wheel mount that supports the grinding wheel. The rotary spindle has a cavity formed in the longitudinal direction of the axis, and a conductive wire connected to the power supply means is disposed through the cavity. This conductive wire is connected to a concave connector provided on the wheel mount. In the grinding device described in Patent Document 1, when a grinding wheel is mounted on a wheel mount, an ultrasonic wave is obtained by connecting a convex connector connected to an ultrasonic transducer to a concave connector provided on the wheel mount. High frequency power is supplied to the vibrator and the grinding wheel vibrates ultrasonically.

  However, in the grinding apparatus described in Patent Document 1, when the grinding wheel is attached to and detached from the wheel mount, the concave connector and the convex connector must be attached and detached, and it takes time to attach and remove the grinding wheel. There is. Paying attention to such problems, the present applicant electrically connects the ultrasonic vibrator of the grinding wheel and the power supply means without going through the concave connector and the convex connector, thereby providing a grinding wheel for the wheel mount. Has been developed and a patent application has already been filed (see Patent Document 2).

  In such a grinding apparatus, two annular electrodes are disposed around an annular ultrasonic vibrator provided on the grinding wheel, and the annular electrode and the ultrasonic vibrator are electrically connected to each other, and power supply means is provided. A pair of electrically connected pressing electrodes is disposed on the wheel mount. In the grinding device described in Patent Document 2, when the grinding wheel is mounted on the wheel mount, the pair of pressing electrodes protrudes toward the two annular electrodes, and the pair of pressing electrodes and the two annular electrodes come into contact with each other. With this configuration, since the ultrasonic vibrator and the power supply means can be electrically connected without using the concave connector and the convex connector, the grinding wheel can be easily attached to and detached from the wheel mount.

JP 2008-23893 A JP 2010-194650 A

  However, in the grinding apparatus described in Patent Document 2, since the pair of pressing electrodes protrudes toward the two annular electrodes to electrically connect the pair of pressing electrodes and the annular electrode, There may be a contact failure between the pair of pressing electrodes and the annular electrode due to an error in the arrangement positions of the two annular electrodes. In addition, because it is electrically connected at the contact point between the pair of pressing electrodes and the two annular electrodes, it is a region where the vibration is canceled during processing due to ultrasonic vibration due to wear of the grinding wheel and changes in the rotation speed of the grinding wheel. When a certain node region changes, a contact failure between electrodes may occur.

  The present invention has been made in view of such points, and in the case of using a grinding wheel for grinding with ultrasonic vibration mounted on a wheel mount, high precision electrode position accuracy is unnecessary, It is an object of the present invention to provide a grinding apparatus that does not cause electrode contact failure even when a node region is changed during ultrasonic vibration machining, and can easily attach and detach a grinding wheel.

  A grinding apparatus according to the present invention comprises a chuck table for holding a workpiece, a grinding means for grinding the workpiece held on the chuck table, and a grinding wheel used for the grinding means. The grinding means includes a spindle housing, a rotary spindle rotatably accommodated in the spindle housing, a wheel mount fixed to a tip of the rotary spindle, and a drive source for rotationally driving the rotary spindle. The grinding wheel has electrical conductivity and is fastened by a screw with the wheel mount, a plurality of grinding wheels disposed in an annular shape at a free end of the wheel base, and the wheel An annular ultrasonic transducer disposed on the base; an annular electrode disposed on the annular ultrasonic transducer; and A movable portion formed in a material that is attracted by a magnetic force, and a movable electrode portion that is accommodated in the central portion of the handle base, and a movable electrode portion that is accommodated in the accommodating portion. A receiving part that holds the movable electrode and is inserted through the opening; a restricting part that restricts the containing part so that the movable electrode protrudes from the opening; and a conductive member that connects the movable electrode part to the annular electrode. The movable electrode portion is housed in the housing portion of the wheel base so as to be able to advance and retreat, and the wheel mount faces the movable electrode in a state where the grinding wheel is fastened with a screw. A fixed electrode having a magnetic force, and the fixed electrode is electrically conductive, communicates with an external power supply source, and contacts the movable electrode unit A fixed electrode holder having, characterized in that it comprises a said contact surface and the magnet parallel disposed inside of the stationary electrode holder by parallel S and N poles of the fixed electrode.

  According to this grinding apparatus, a fixed electrode having a magnetic force is disposed on the wheel mount, and a movable electrode portion including a movable electrode formed of a material attracted by the magnetic force is disposed in the housing portion of the wheel base. Since the portion is housed in the housing portion of the wheel base so as to be able to advance and retreat, when the grinding wheel is fastened and attached to the wheel mount, the movable electrode portion is attracted by the magnetic force of the fixed electrode and comes into contact with the fixed electrode. As a result, since the fixed electrode and the movable electrode are automatically connected by magnetic force only by mounting the grinding wheel to the wheel mount without using a connector or the like, the grinding wheel can be easily connected. Further, since the movable electrode portion is brought into a non-contact state from the wheel base of the grinding wheel, the vibration of the wheel base is not transmitted to the movable electrode portion, and the contact failure of the electrode due to the vibration can be avoided. Furthermore, since the movable electrode and the fixed electrode come into contact with each other by the magnetic force of the fixed electrode, it is possible to electrically connect the fixed electrode and the movable electrode without requiring high-precision electrode position accuracy, Even when the node region, which is a region in which vibration is canceled at the time of processing accompanied by vibration, changes, it is possible to suppress a contact failure between the fixed electrode and the movable electrode. In addition, since the fixed electrode having magnetic force is disposed on the wheel mount away from the workpiece, the influence of the magnetic force on the workpiece can be reduced. Furthermore, since a fixed electrode having a magnetic force is disposed on the wheel mount without using a magnet in the grinding wheel, the grinding wheel that is a consumable can be configured at low cost. Further, since the fixed electrode and the movable electrode portion are disposed in the center portion of the wheel mount, the connection state can be stably maintained without being affected by the centrifugal force accompanying the rotation of the grinding wheel.

  According to the present invention, when a grinding wheel that performs grinding with ultrasonic vibration is mounted on a wheel mount and used, high-precision electrode position accuracy is not necessary, and node region change during ultrasonic vibration machining is achieved. Therefore, it is possible to provide a grinding apparatus that does not cause poor electrode contact and can easily attach and detach the grinding wheel.

FIG. 1 is an external perspective view of a grinding apparatus according to the present embodiment. FIG. 2 is a cross-sectional view schematically showing a partial configuration of the grinding apparatus according to the present embodiment. FIG. 3 is a perspective view of the periphery of the wheel mount of the grinding apparatus according to the present embodiment. FIG. 4 is a perspective view of a grinding wheel of the grinding apparatus according to the present embodiment. FIG. 5 is a schematic cross-sectional view of the wheel mount and the grinding wheel of the grinding apparatus according to the present embodiment. FIG. 6 is a perspective view of the magnet of the grinding apparatus according to the present embodiment. FIG. 7 is a schematic cross-sectional view of the wheel mount and the grinding wheel of the grinding apparatus according to the present embodiment. FIG. 8 is an explanatory view of the operation of the grinding apparatus according to the present embodiment. FIG. 9 is a schematic cross-sectional view of a wheel mount and grinding wheel provided with other magnets.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an external perspective view showing an example of a grinding apparatus 1 according to the present embodiment. In the following, for the sake of convenience of explanation, the lower left side shown in FIG. 1 is called the front side of the grinding apparatus 1, and the upper right side shown in FIG. 1 is called the rear side of the grinding apparatus 1. In the following, for convenience of explanation, the vertical direction shown in FIG.

  As shown in FIG. 1, a grinding apparatus 1 according to the present embodiment has a base 100 that constitutes a housing of the apparatus. The base 100 includes a main portion 101 extending in the front-rear direction of the grinding apparatus 1 and a wall portion 102 provided to extend upward at the rear end portion of the main portion 101. On the front side of the upper surface of the main part 101, an operation panel 103 that receives instructions for the grinding apparatus 1 is provided. On the rear side of the operation panel 103, there is provided a table support base 105 that supports a chuck table 104 holding a workpiece W (workpiece) so as to be movable back and forth. On the other hand, a pair of guide rails 106 extending in the vertical direction are provided on the front surface of the wall portion 102. A grinding unit 21 (grinding means) is mounted on these guide rails 106 so as to be movable in the vertical direction.

  The grinding unit 21 is driven by the grinding feed mechanism 11 and can be moved up and down. The grinding feed mechanism 11 includes a ball screw 111 that is arranged in parallel to the guide rail 106 and extends in the vertical direction, a motor 112 that is connected to one end of the ball screw 111 and rotates the ball screw 111 in both forward and reverse directions, and an interior that is screwed into the ball screw 111. And a support base 114 connected to the transfer base 113 and supporting the grinding unit 21. The support base 114 is connected to the transfer base 113. The grinding feed mechanism 11 raises and lowers the grinding unit 21 by rotating the ball screw 111 driven by the motor 112 and moving the moving base 113 up and down guided by the guide rail 106.

  The grinding unit 21 includes a spindle unit 22 mounted on the moving base 113. The spindle unit 22 is supported by the support portion 114. The spindle unit 22 includes a spindle housing 221 supported by the support portion 114, and a rotating spindle 222 (not shown in FIG. 1, refer to FIG. 2) rotatably disposed in the spindle housing 221. . The lower end portion of the rotating spindle 222 protrudes downward beyond the lower end portion of the spindle housing 221, and a disc-shaped wheel mount 31 is connected to the tip end of the lower end portion. A grinding wheel 41 used for grinding by the grinding unit 21 is fixed to the wheel mount 31. The wheel mount 31 is disposed so as to be able to face the chuck table 104 whose upper surface (surface) is formed in a horizontal plane.

  FIG. 2 is a cross-sectional view schematically showing a partial configuration of the grinding apparatus 1 according to the present embodiment. As shown in FIG. 2, the rotary spindle 222 is housed in the spindle housing 221 by being rotatably supported by the spindle housing 221 in a non-contact state.

  The grinding unit 21 includes an electric motor 23 as a drive source that rotationally drives the rotary spindle 222. The electric motor 23 includes a rotor 231 connected to an intermediate portion of the rotary spindle 222 and a stator coil 232 disposed on the outer peripheral side of the rotor 231. The electric motor 23 operates by receiving power supply from the power supply means 51.

  The power supply means 51 includes a voltage adjustment means 512 interposed between the AC power source 511 and the power supply coil 242b of the power supply means 242, a frequency adjustment means 513 for adjusting the frequency of the AC power supplied to the power supply coil 242b, The control unit 514 controls the adjustment unit 512 and the frequency adjustment unit 513, and the input unit 515 is used to input the amplitude of the ultrasonic vibration.

  The AC power supply 511 is connected to the stator coil 232 of the electric motor 23 via the control circuit 516 and the wiring 517. The rotor 231 and the rotating spindle 222 can be rotated by supplying AC power to the stator coil 232.

  A small-diameter tip 223 is provided at one end (lower end) of the rotary spindle 222. The wheel mount 31 is fixed to the lower end portion of the small diameter tip portion 223. A rotary transformer 24 is provided at the other end (upper end) of the rotary spindle 222. The rotary transformer 24 includes a power receiving unit 241 connected to the upper end of the rotary spindle 222 and a power feeding unit 242 located on the outer peripheral side of the power receiving unit 241.

  The power receiving unit 241 includes a rotor core 241a connected to the rotary spindle 222 and a power receiving coil 241b wound around the rotor core 241a. The power feeding unit 242 includes a stator core 242a disposed on the outer peripheral side of the rotor core 241a constituting the power receiving unit 241 and a power feeding coil 242b disposed on the stator core 242a. Note that AC power is supplied to the power supply coil 242b through the wiring 518.

  Conductive wires 25 a and 25 b are connected to the power receiving coil 241 b of the power receiving means 241. The conductive wire 25a passes through a through hole 222a formed in the axial direction of the rotary spindle 222 and is connected to a fixed electrode portion 62 (not shown in FIG. 2, refer to FIG. 3) of the wheel mount 31 described later.

  Here, the configuration of the wheel mount 31 fixed to the lower end (tip) of the rotary spindle 222 and the grinding wheel 41 attached to the wheel mount 31 will be described. FIG. 3 is a perspective view of the periphery of the wheel mount 31 of the grinding apparatus 1 according to the present embodiment. In FIG. 3, the wheel mount 31 with the grinding wheel 41 removed is shown from below. FIG. 4 is a perspective view of the grinding wheel 41 of the grinding apparatus 1 according to the present embodiment. In FIG. 4, the grinding wheel 41 is shown from above.

  As shown in FIG. 3, the wheel mount 31 is made of a conductive metal material and has a generally disc shape. The wheel mount 31 has a conductive wire 25b connected to itself. A circular hole 31 a that communicates with the through hole 222 a of the rotary spindle 222 is provided at the center of the lower surface of the wheel mount 31. As will be described in detail later, an insulating member 61 having a hole 61a provided in the center is attached to the circular hole 31a. Inside the insulating member 61, the fixed electrode 62 is held with a part thereof exposed from the hole 61a. In addition, a plurality of (six in this embodiment) screw holes 31 b penetrating the wheel mount 31 in the vertical direction are provided on the outer peripheral edge of the wheel mount 31.

  As shown in FIG. 4, the grinding wheel 41 is made of a conductive metal material and has a generally disc shape. The grinding wheel 41 has an annular shape, a mounting ring 411 fixed to the wheel mount 31, a wheel base 413 formed integrally with the mounting ring 411 via an annular coupling portion 412, and a wheel base 413. And a plurality of grinding wheels 414 arranged annularly at the free end.

  A plurality (six in this embodiment) of screw holes 411 a that penetrates in the vertical direction of the grinding wheel 41 are provided on the outer peripheral edge of the mounting ring 411. The screw hole 411 a is disposed at a position corresponding to the screw hole 31 b provided in the wheel mount 31. The grinding wheel 41 is attached to the wheel mount 31 by fastening the screw hole 31b of the wheel mount 31 and the screw hole 411a of the attachment ring 411 with a screw 31c (see FIG. 2).

  At the center of the wheel base 413, a circular accommodating portion 413a is provided that opens toward the wheel mount 31 (upper side). More specifically, the accommodating part 413a is comprised by the through-hole which penetrates the wheel base 413 to an up-down direction. An annular ultrasonic transducer 415 is disposed around the accommodating portion 413a on the wheel base 413 so as to be concentric with the circular opening constituting the accommodating portion 413a.

  Examples of the annular ultrasonic transducer 415 include barium titanate (BaTiO3), lead zirconate titanate (Pb (Zi, Ti) O3), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), and niobium. Sodium potassium acid (K, N) (KNbO3) or the like can be used.

  An annular electrode 416 having substantially the same shape as the annular ultrasonic transducer 415 is laminated and disposed above the annular ultrasonic transducer 415. For example, the annular electrode 416 is fixed to the annular ultrasonic transducer 415 with an adhesive or the like. The annular electrode 416 is electrically connected to a later-described movable electrode portion 71 (more specifically, a restriction portion 712 constituting the movable electrode portion 71) via a flexible conductive wire 417.

  The mounting ring 411 and the wheel base 413 are connected by an annular connecting portion 412. The annular connecting portion 412 is provided with a plurality of slits 412 a along the circumferential direction of the wheel base 413. These slits 412 a are provided so as to penetrate the annular coupling portion 412 in the vertical direction (see FIG. 5), and play a role of suppressing transmission of ultrasonic vibrations by the annular ultrasonic transducer 415 to the wheel mount 31.

  The movable electrode portion 71 is accommodated in the accommodating portion 413a of the wheel base 413 so as to be able to advance and retract in the vertical direction. The movable electrode portion 71 penetrates the substantially cylindrical portion 711 to be inserted through the opening of the housing portion 413a, a disc-shaped restriction portion 712 provided on the upper surface of the portion 711 to be received, and the restriction portion 712. And a movable electrode 713 held by the receiving portion 711 and a disk-shaped engaging portion 714 (not shown in FIG. 4, refer to FIG. 5) provided on the lower surface of the receiving portion 711. Composed.

  5 and 7 are schematic cross-sectional views of the wheel mount 31 and the grinding wheel 41 of the grinding apparatus 1 according to the present embodiment. FIG. 6 is a perspective view of the magnet of the grinding apparatus according to the present embodiment. 5 shows a state before mounting (a state in which the grinding wheel 41 is separated from the wheel mount 31) in which the grinding wheel 41 is opposed to the wheel mount 31, and FIG. 7 shows the grinding wheel 41 on the wheel mount 31. The state where is attached is shown.

  As shown in FIG. 5, a mounting ring 411 is connected to the upper side of the wheel base 413 via an annular connecting portion 412. Therefore, a predetermined space is formed between the upper surface 413b of the wheel base 413 and the lower surface 31d of the wheel mount 31 when the grinding wheel 41 is mounted on the wheel mount 31 (see FIG. 7). The movable electrode portion 71 described above is accommodated in the space so as to be able to advance and retreat in an accommodating portion 413 a provided on the wheel base 413.

  The restricting portion 712 constituting the movable electrode portion 71 is formed to have a slightly larger width dimension in the radial direction than the opening of the wheel base 413 (the opening of the accommodating portion 413a). That is, it has a larger diameter than the opening of the wheel base 413 and is arranged so as to cover the opening. The restricting portion 712 moves the movable electrode portion 71 (more specifically, the accommodated portion 711) in a state where the outer peripheral edge of the lower surface of the restricting portion 712 and the opening edge of the accommodating portion 413a of the wheel base 413 are in contact. Suspend and regulate the drop of the movable electrode portion 71 into the housing portion 413a. When the restricting portion 712 restricts the fall of the accommodated portion 711 into the accommodating portion 413a, the movable electrode 713 is maintained in a state of protruding from the opening of the wheel base 413 (the opening of the accommodating portion 413a).

  The restricting portion 712 is made of a conductive metal material. A flexible conductive wire 417 is connected between the restricting portion 712 and the annular electrode 416 laminated on the annular ultrasonic transducer 415. That is, in a state where the grinding wheel 41 is separated from the wheel mount 31, the annular ultrasonic transducer 415 and the wheel base 413 are electrically connected via the flexible conductor 417 and the restricting portion 712. On the other hand, since the back surface side of the annular ultrasonic transducer 415 is in contact with the conductive wheel base 413, the upper surface side and the lower surface side of the ultrasonic transducer 415 are short-circuited.

  When the grinding wheel 41 is not attached to the wheel mount 31 as in storage, the grinding wheel 41 can expand and contract according to the surrounding atmosphere. Such expansion and contraction of the grinding wheel 41 may be caused by factors such as a temperature change when moving from outside air in midsummer to a room whose temperature is controlled by an air conditioning facility. An external stress typified by expansion and contraction of the grinding wheel 41 causes a piezoelectric action in the annular ultrasonic vibrator 415. Under a situation where an external stress is applied, the surface of the annular ultrasonic transducer 415 may be charged by the piezoelectric action of the annular ultrasonic transducer 415. When such a situation occurs, it becomes difficult to handle the grinding wheel 41 safely, for example, when the wheel mount 31 is attached. In order to cope with such a situation, in the grinding wheel 41 according to the present embodiment, the regulating portion 712 made of a conductive metal material is electrically connected to the annular ultrasonic transducer 415, and the wheel mount The upper surface side and the lower surface side of the annular ultrasonic transducer 415 are short-circuited by bringing the regulating portion 712 into contact with the wheel base 41 while the grinding wheel 41 is separated from the wheel 31. As a result, the electric charge charged to the annular ultrasonic vibrator 415 by the piezoelectric action can be discharged (that is, charging due to the piezoelectric action by the annular ultrasonic vibrator 415 can be prevented), and the grinding wheel 41 removed after grinding can be safely used. Can be handled.

  The movable electrode 713 is made of a material attracted by magnetic force, for example, iron or an alloy of iron and nickel. The movable electrode 713 is disposed at a substantially central portion of the restricting portion 712 and is provided so that at least a part protrudes upward from the upper surface of the restricting portion 712. A flat portion is provided at the upper end of the movable electrode 713. This flat portion constitutes an attracting surface of a magnet 622 constituting a fixed electrode 62 described later.

  The engaging portion 714 is provided on the lower surface of the accommodated portion 711 and is disposed in the accommodating portion 413a. Similar to the restricting portion 712, the engaging portion 714 has a slightly larger width in the radial direction than the opening of the wheel base 413 (the opening of the accommodating portion 413a), and the accommodated portion 711 is located above the accommodating portion 413a. It plays a role of preventing separation to the side or the lower side. Here, the movable electrode portion 71 is configured such that the magnetic permeability of the movable electrode 713 is high. In the present embodiment, the accommodating portion 711, the regulating portion 712, and the engaging portion 714 are made of aluminum or the like with respect to the movable electrode 713 made of iron.

  On the other hand, an insulating member 61 is attached to the circular hole 31 a provided in the center of the wheel mount 31. The insulating member 61 includes an insertion portion 611 inserted into the circular hole 31a and a flat portion 612 having a disk shape provided at the lower end of the insertion portion 611. The lower surface of the planar portion 612 is disposed on the same plane as the lower surface 31 d of the wheel mount 31 in a state where the insulating member 61 is completely attached to the wheel mount 31. A hole 61 a is provided in the center of the flat portion 612.

  The fixed electrode 62 is accommodated in the insertion portion 611. The fixed electrode 62 is accommodated in the insertion portion 611 so that a part thereof is exposed from the hole 61 a of the flat portion 612. The fixed electrode 62 includes a fixed electrode holding part 621 and a magnet 621 covered with the fixed electrode holding part 621. By providing the magnet 622 inside, the fixed electrode 62 functions as a fixed electrode having magnetic force. A part of the conductive member 621 that covers the lower surface of the magnet 622 is provided thinner than a portion that covers the other surface (for example, the upper surface or side surface of the magnet 621). By providing a thin part of the conductive member 621 corresponding to the lower surface of the magnet 622, the magnetic force of the magnet 622 is appropriately applied to the movable electrode portion 71 (more specifically, the movable electrode 713) disposed on the wheel base 413. It is configured to work.

  The fixed electrode holding part 621 is made of a conductive metal material and has a contact surface 621a (the lower surface of the fixed electrode 62) that comes into contact with the movable electrode part 71. The fixed electrode holding part 621 is insulated by the insulating member 61, and the conductive wire 25 a is connected through the insulating member 61. Thereby, the fixed electrode 62 is connected to the power supply means 51 through the rotary transformer 24.

  The magnet 622 is disposed inside the fixed electrode holding part 621. In this embodiment, as shown in FIG. 6, magnet 622 has a cylindrical shape, and is formed by a pair of S and N poles partitioned by a plane including the central axis. Here, the magnet 622 is accommodated in the fixed electrode holding portion 621 so that the central axis is parallel to the vertical direction. Therefore, the S pole and the N pole of the magnet 622 are arranged in parallel with the contact surface 621 a of the fixed electrode 62.

  A movable electrode portion 71 housed in a housing portion 413a opened in the center of the wheel base 413, a fixed electrode 62 held in an insulating member 61 attached to a circular hole 31a near the center of the free end surface of the wheel mount 31, Are arranged at positions facing each other in a state where the grinding wheel 41 is fastened to the wheel mount 31 by screws 31c. As shown in FIG. 5, in a state before the grinding wheel 41 is fastened to the wheel mount 31 by the screw 31 c, the magnetic force of the fixed electrode 62 does not act, and the movable electrode portion 71 has a receiving portion 711 that has a receiving portion. It is maintained in the state accommodated in 413a.

  On the other hand, when the grinding wheel 41 is fastened to the wheel mount 31 by the screw 31c, the movable electrode 713 is attracted by the magnetic force of the fixed electrode 62 as shown in FIG. ) As a result, the movable electrode 713 comes into contact with the contact surface 621a of the fixed electrode 62, the restricting portion 712 is separated from the opening edge of the housing portion 413a of the wheel base 413, and the movable electrode portion 71 is not in contact with the wheel base 413. It becomes a state.

  In addition, the restricting portion 712 maintains a state where it is electrically connected to the annular ultrasonic transducer 415 (annular electrode 416) via the flexible conductive wire 417. Therefore, the fixed electrode 62 and the movable electrode 713 are electrically connected, and the annular ultrasonic transducer 415 electrically connected to the movable electrode 713 via the flexible conductive wire 417 is electrically connected to the fixed electrode 62. Connected. As a result, power is supplied from the power supply means 51 to the annular ultrasonic vibrator 415 via the fixed electrode 62, and grinding by the grinding wheel 41 accompanied by ultrasonic vibration becomes possible.

  In the state where the fixed electrode 62 and the movable electrode 713 are connected, the electric charge generated on the back surface side of the annular ultrasonic transducer 415 is a wheel base 413 made of a conductive member and a wheel fastened to the wheel base 413. The signal is output through the conductive wire 25 b connected to the mount 31 and the wheel mount 31. Then, it is grounded via the ground terminal of the grinding device 1.

  As described above, in the grinding apparatus 1 according to the present embodiment, the fixed electrode 62 having magnetic force is disposed on the wheel mount 31 and the material attracted by the magnetic force into the accommodating portion 413a of the wheel base 413 of the grinding wheel 41. Since the movable electrode portion 71 including the movable electrode 713 formed in the above is disposed and the movable electrode portion 71 is housed in the housing portion 413a of the wheel base 413 so as to be able to advance and retreat, the grinding wheel 41 is mounted on the wheel mount 31. At this time, the movable electrode portion 71 is attracted by the magnetic force of the fixed electrode 302 and automatically contacts the fixed electrode 62. Thereby, since the ultrasonic transducer | vibrator 415 and the electric power supply means 51 can be electrically connected without going through a connector etc., it becomes possible to attach or detach the grinding wheel 41 easily.

  In particular, since the movable electrode 713 and the fixed electrode 62 come into contact with each other by the magnetic force of the fixed electrode 62, the fixed electrode 62 and the movable electrode 713 can be electrically connected without requiring high-precision electrode position accuracy, and the ultrasonic wave Even when a node region, which is a region in which vibration is canceled during processing involving vibration, changes, contact failure between the fixed electrode 62 and the movable electrode 713 can be suppressed.

  Further, since the fixed electrode 62 having magnetic force is disposed on the wheel mount 31 away from the workpiece W (workpiece), the influence of the magnetic force on the workpiece W can be reduced. Further, since the grinding wheel 41 does not use a magnet and the wheel mount 31 is provided with the fixed electrode 62 having a magnetic force, the grinding wheel 41 that is a consumable can be configured at low cost. Furthermore, since the movable electrode portion 71 is disposed at the center portion of the wheel mount 31, the connection state can be stably maintained without being affected by the centrifugal force accompanying the rotation of the grinding wheel 41.

  Further, by arranging the magnet 622 in parallel with the contact surface 621a of the fixed electrode 62 so that the south pole and the north pole are arranged in parallel, the magnetic force lines generated by the magnet 622 are below the movable electrode portion 71 in contact with the fixed electrode 62. Can be suppressed. FIG. 8 is an explanatory view of the operation of the grinding apparatus according to the present embodiment. FIG. 9 is a schematic cross-sectional view of a wheel mount and grinding wheel provided with other magnets. As shown in FIG. 8, in the present embodiment, the magnet 622 is parallel to the contact surface 621a of the fixed electrode 62 and the S pole and the N pole are arranged in parallel, so the orientation parallel to the contact surface 621a of the fixed electrode 62 is That is, the magnet 622 generates magnetic lines of force (magnetic force) along the contact surface 621a. Most of the magnetic force lines M1 above the magnet 622 are formed in the through hole 222a. Here, below the magnet 622, since the movable electrode 713 having a higher magnetic permeability than the other members is in contact with the fixed electrode 62, a magnetic force line M2 generated by the magnet 622 is formed along the movable electrode 72. It is suppressed that the magnetic lines of force outside the movable electrode 713 come off. That is, the magnetic force line M <b> 2 below the magnet 622 is formed inside the movable electrode portion 71. On the other hand, as shown in FIG. 9, when the magnets 623 are stacked in the vertical direction and the south pole and the north pole are arranged, the movable electrode 713 having a higher magnetic permeability than the other members comes into contact with the fixed electrode 62. Therefore, the magnet 622 and the movable electrode 713 function as one magnet, and an N pole is formed in a region below the movable electrode 713. Accordingly, the magnetic lines of force M3 and M4 generated by the magnet 622 and the movable electrode 713 are formed to be long in the vertical direction, and are formed to a region below the movable electrode portion 71. From the above, in the present embodiment, it is possible to suppress the formation of magnetic lines of force in the region below the movable electrode portion 71, so that the magnetic material (foreign matter) mixed in the atmosphere during grinding by the grinding apparatus 1 can be prevented. Adhesion to the movable electrode portion 71 can be suppressed. Thereby, the malfunction of the movable electrode part 71 etc. can be suppressed and the fall of durability resulting from the malfunction of a movable part can be suppressed.

  Next, the operation of the grinding apparatus 1 when the workpiece (workpiece) W is ground using the grinding apparatus 1 shown in FIG. 1 will be described. The workpiece W is held on the chuck table 104 with the tape T attached to the held surface. Then, when the chuck table 104 moves rearward, the workpiece W is positioned in the lower region of the grinding unit 21.

  Next, while rotating the chuck table 2 at a rotational speed of about 300 RPM and rotating the rotary spindle 222, the grinding feed mechanism 11 rotates the grinding unit 21 while rotating the grinding wheel 41 at a rotational speed of about 6000 RPM, for example. Is lowered, the rotating grinding wheel 414 can be brought into contact with the workpiece W for grinding. Then, when the workpiece W reaches a desired thickness, the grinding unit 21 is raised and the grinding is finished.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  In the above embodiment, a cylindrical magnet is used. However, if the S pole and the N pole are in parallel with the contact surface 621a of the fixed electrode 62, for example, a cylindrical shape, a polygonal column, or a sphere is used. There may be. Further, a plurality of pairs of S poles and N poles may be arranged in parallel. For example, the magnet 622 may be configured by collecting a plurality of magnets.

  Further, in the above-described embodiment, the movable electrode portion 71 of the accommodated portion 711 is protruded from the opening of the wheel base 41 by the restriction portion 712 provided on the upper surface of the accommodated portion 711. Although the case of restricting movement is described, the configuration of the restricting portion 712 that restricts the movement of the accommodated portion 711 is not limited to this, and can be changed as appropriate. For example, the engaging portion 714 provided on the lower surface of the accommodated portion 711 can also function as the restricting portion 712.

DESCRIPTION OF SYMBOLS 1 Grinding apparatus 11 Grinding feed mechanism 100 Base 101 Main part 102 Wall part 103 Operation panel 104 Chuck table 105 Table support base 106 Guide rail 111 Ball screw 112 Motor 113 Moving base 114 Support part 21 Grinding unit (grinding means)
22 Spindle unit 221 Spindle housing 222 Rotating spindle 222a Through hole 223 Small diameter tip 23 Electric motor 231 Rotor 232 Stator coil 24 Rotary transformer 241 Power receiving means 242 Power feeding means 241a Rotor core 241b Power receiving coil 242a Stator core 242b Power feeding coil 25 Conductive wire 31 Mount 31 Circular hole 31b Screw hole 31c Screw 41 Grinding wheel 411 Mounting ring 411a Screw hole 412 Annular connecting part 412a Slit 413 Wheel base 413a Housing part 414 Grinding wheel 415 Annular ultrasonic vibrator 416 Annular electrode 417 Flexible lead 51 Power supply means 511 512 Voltage adjusting means 513 Frequency adjusting means 514 Control means 515 Input means 516 Control circuit 517 wiring 518 wiring 61 insulating member 61a hole 611 insertion portion 612 flat portion 62 fixed electrode 621 fixed electrode holding portion 622 magnet 71 the movable electrode portion 711 installed portion 712 restricting portion 713 movable electrode 714 engaging part

Claims (1)

A grinding apparatus comprising: a chuck table for holding a workpiece; a grinding means for grinding a workpiece held on the chuck table; and a grinding wheel used for the grinding means,
The grinding means includes a spindle housing, a rotating spindle rotatably accommodated in the spindle housing, a wheel mount fixed to a tip of the rotating spindle, and a drive source for rotationally driving the rotating spindle,
The grinding wheel is electrically conductive and is fastened by a screw with the wheel mount, a plurality of grinding wheels disposed in an annular shape at a free end of the wheel base, and disposed on the wheel base. An annular ultrasonic transducer, an annular electrode disposed in a stack on the annular ultrasonic transducer, an accommodating portion that is open at the center of the wheel base and on the wheel mount side, and accommodated in the accommodating portion A movable electrode portion,
The movable electrode portion includes a movable electrode formed of a material attracted by magnetic force, a receiving portion that holds the movable electrode and is inserted into the opening, and the received electrode so that the movable electrode protrudes from the opening. A restricting portion for restricting a portion, and a conductive flexible conductive wire connected to the annular electrode from the movable electrode portion, and the movable electrode portion is accommodated in the accommodating portion of the wheel base so as to be capable of moving forward and backward.
The wheel mount has a fixed electrode having a magnetic force disposed at a position facing the movable electrode in a state in which the grinding wheel is fastened by a screw and disposed near the free end surface of the center,
The fixed electrode has electrical conductivity, communicates with an external power supply source, has a contact surface that contacts the movable electrode portion, and an S pole parallel to the contact surface of the fixed electrode. And a magnet disposed inside the fixed electrode holding portion with N poles arranged in parallel.

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