JP2013132721A - Grinding wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively transmit ultrasonic vibration, generated from an ultrasonic vibrator, to a grinding stone in simple construction.SOLUTION: A grinding wheel (41) is mounted on a wheel mount (31) fixed to the tip of the rotating spindle (222) of a grinding device (1). The wheel includes a mount base (411) having an opening (411a) at its center and being mounted on the wheel mount (31); a circular base (412) having a top side and an under side, having a plurality of grinding stones (414) fixed to the periphery of the under side and having an opening (412a) at its center; a circular sidewall (415) for coupling the periphery of the mount base (411) with the periphery of the circular base (412); and a circular ultrasonic vibrator (413) arranged at the center of the topside (412b), while surrounding the opening (412a) of the circular base (412).

Description

  The present invention relates to a grinding wheel, for example, a grinding wheel mounted on a grinding apparatus for grinding a workpiece such as a semiconductor wafer 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 already been filed (for example, see Patent Document 1).

JP 2008-23893 A

  However, the grinding wheel mounted on the grinding device described in Patent Document 1 has a problem that its structure is relatively complicated and its manufacturing cost is high.

  The present invention has been made in view of such points, and an object thereof is to provide a grinding wheel that can effectively transmit ultrasonic vibration generated from an ultrasonic vibrator to a grinding wheel with a simple configuration. And

  A grinding wheel according to the present invention is a grinding wheel mounted on a wheel mount fixed to a spindle tip of a grinding apparatus, and has a mount base having an opening in the center and mounted on the wheel mount, and a first surface. And an annular base having a second surface opposite to the first surface, a plurality of grinding wheels being fixed to the outer peripheral portion of the second surface and having an opening in the center portion, and an outer periphery of the mount base An annular side wall connecting the outer periphery of the annular base and the annular ultrasonic transducer disposed around the opening of the annular base and disposed in the center of the first surface; It is characterized by comprising.

  According to this grinding wheel, an opening is formed in the annular base, and an annular ultrasonic vibrator is disposed so as to surround the opening. Since the annular base can be easily deformed, the ultrasonic vibration generated from the ultrasonic vibrator can be effectively transmitted to the grinding wheel with a simple configuration.

  In the grinding wheel, the first surface of the annular base is formed in a tapered shape in which the thickness decreases from the position where the outer periphery of the ultrasonic transducer is disposed to the annular side wall. Preferably it is.

  According to the present invention, it is possible to effectively transmit ultrasonic vibration generated from an ultrasonic vibrator to a grinding wheel with a simple configuration.

It is an external appearance perspective view of the grinding device concerning this embodiment. It is sectional drawing which shows roughly the structure of a part of grinding apparatus which concerns on the said embodiment. It is a perspective view around the wheel mount of the grinding device according to the embodiment. It is a perspective view of the grinding wheel of the grinding device concerning the above-mentioned embodiment. It is a cross-sectional schematic diagram of the grinding wheel of the grinding apparatus which concerns on the said embodiment. It is explanatory drawing of the amplitude amount of the grinding wheel at the time of the ultrasonic vibration of the grinding wheel of the grinding apparatus which concerns on a present Example.

Hereinafter, embodiments 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. 1 is referred to as the vertical direction of the grinding apparatus 1.

  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. The grinding unit 21 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.

  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 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.

  A conductive wire 25 is connected to the power receiving coil 241 b of the power receiving means 241. A part of the conductive wire 25 passes through a through-hole 222a formed in the axial direction of the rotary spindle 222, and is mounted in the small-diameter tip 223 (described later, not shown in FIG. 2, see FIG. 3). )It is connected to the.

  Here, the configuration of the wheel mount 31 fixed to the lower end portion 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. FIG. 4 is a perspective view of the grinding wheel 41 of the grinding apparatus 1 according to the present embodiment.

  As shown in FIG. 3, the wheel mount 31 is provided with a plurality (four in the present embodiment) of screw holes 31 a. The grinding wheel 41 is attached to the wheel mount 31 by inserting the bolt 31b into the screw hole 31a and screwing the bolt 31b into the screw hole 411b of the grinding wheel 41 (mount base 411).

  Further, as shown in FIG. 3, a connector insertion hole 222b having an enlarged diameter is formed at the tip end (lower end) of the through hole 222a formed in the rotary spindle 222. The concave connector 224 is inserted into the connector insertion hole 222b. The concave connector 224 is fitted with a convex connector 225 connected to an ultrasonic transducer 413 described later.

  As shown in FIG. 4, the grinding wheel 41 has a mount base 411 that is detachably attached to the wheel mount 31. The mount base 411 generally has an annular shape, and a circular opening 411a is formed at the center thereof. A plurality of (four in this embodiment) screw holes 411b are provided at equal intervals around the opening 411a. The screw hole 411 b is disposed at a position corresponding to the screw hole 31 a of the wheel mount 31.

  Further, the grinding wheel 41 has an annular base 412 disposed to face the mount base 411. The annular base 412 generally has an annular shape, and the outer dimensions thereof are set to the same dimensions as the mount base 411. A circular opening 412 a is formed at the center of the annular base 412. The opening 412 a is disposed at a position corresponding to the opening 411 a of the mount base 411. The opening 412 a has a smaller opening diameter than the opening 411 a of the mount base 411.

  An annular ultrasonic transducer 413 is disposed around the opening 412 a on the upper surface 412 b constituting the first surface of the annular base 412. The ultrasonic transducer 413 is disposed so as to surround the opening 412 a and is disposed at the center of the upper surface 412 b of the annular base 412. The ultrasonic transducer 413 is connected with a pair of conductive wires 225a connected to the convex connector 225 described above. These conductive lines 225 a pass through the opening 411 a of the mount base 411 and are connected to the ultrasonic transducer 413.

As the ultrasonic vibrator 413, for example, barium titanate (BaTiO ₃ ), lead zirconate titanate (Pb (Zi, Ti) O ₃ ), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO _3). ), Potassium sodium niobate (K, N) (KNbO ₃ ), and the like.

  A plurality of grinding wheels 414 are fixed to a lower surface 412c (not shown in FIG. 4, refer to FIG. 5) constituting the second surface of the annular base 412. The plurality of grinding wheels 414 are annularly arranged on the outer peripheral portion (more specifically, the outer peripheral edge portion) of the lower surface 412 c of the annular base 412. These grinding wheels 414 are fixed to the lower surface 412c of the annular base 412 with, for example, an adhesive.

  The mount base 411 and the annular base 412 are connected to each other by an annular side wall 415. The annular side wall 415 includes an outer peripheral portion (more specifically, an outer peripheral portion) of the lower surface of the mount base 411 and an outer peripheral portion (more specifically, an outer peripheral portion) of the upper surface 412b of the annular base 412. And The annular side wall 415 extends in the vertical direction shown in FIG. 4 between the outer peripheral portion of the lower surface of the mount base 411 and the outer peripheral portion of the upper surface 412b of the annular base 412 and has an annular shape. ing.

  The mount base 411, the annular base 412 and the annular side wall 415 constituting the grinding wheel 41 are integrally formed using a material such as aluminum, stainless steel (SUS), titanium, or the like. Then, the ultrasonic vibrator 413 and the grinding wheel 414 are disposed at predetermined positions on the integrally formed grinding wheel 41 (more specifically, the upper surface 412b of the annular base 412 and the lower surface 412c disposed on the opposite side). Is fixed.

  FIG. 5 is a schematic cross-sectional view of the grinding wheel 41 of the grinding apparatus 1 according to the present embodiment. 5A shows a schematic cross-sectional view of the grinding wheel 41 of the grinding apparatus 1 according to the first embodiment, and FIG. 5B shows the grinding wheel 41 of the grinding apparatus 1 according to the second embodiment. The cross-sectional schematic diagram is shown.

  As shown in FIGS. 5A and 5B, in the grinding wheel 41 of the grinding apparatus 1 according to the present embodiment, a mount base with a fixed distance (a distance corresponding to the length in the vertical direction of the annular side wall 415) sandwiched therebetween. 411 and the annular base 412 are arranged to face each other. The opening 412 a formed in the annular base 412 is disposed at a position corresponding to the central portion of the opening 411 a formed in the mount base 411. The ultrasonic transducer 413 is disposed at a position corresponding to the opening 411 a on the upper surface 412 b of the annular base 412.

  In the grinding wheel 41 according to the first embodiment, the mount base 411, the annular base 412 and the annular side wall 415 are each provided with a uniform thickness dimension (wall thickness). The mount base 411 and the annular base 412 are provided with substantially the same thickness. On the other hand, the annular side wall 415 is provided with a thickness smaller than the thickness of the mount base 411 and the annular base 412.

  The thickness dimension of the annular side wall 415 is preferably set to a dimension within a range of 0.1 mm to 2.0 mm, for example. By setting the thickness dimension of the annular side wall 415 to such a dimension, the ultrasonic vibration from the ultrasonic vibrator 413 is allowed to be transmitted to the annular base 412 and the annular side wall while allowing the ultrasonic vibration by the ultrasonic vibrator 413. Transmission to the mount base 411 via 415 can be suppressed.

  The grinding wheel 41 according to the second embodiment shown in FIG. 5B is different from the grinding wheel 41 according to the first embodiment shown in FIG. 5A in the configuration of the annular base 412. In the annular base 412 according to the first embodiment, the upper surface 412b is a flat surface. On the other hand, the annular base 412 according to the second embodiment is different from the annular base 412 according to the first embodiment in that a tapered shape is formed on a part of the upper surface 412b. To do.

  In the annular base 412 according to the second embodiment, as shown in FIG. 5B, the thickness of the upper surface 412b decreases from the position corresponding to the outer peripheral portion of the ultrasonic transducer 413 to the annular side wall 415. A tapered surface 412d is formed. Therefore, in the annular base 412, the thickness dimension of the portion connected to the annular side wall 415 is the thinnest. In the annular base 412, the portion where the ultrasonic transducer 413 is disposed is configured as a flat surface.

  Hereinafter, 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 104 at a rotational speed of about 300 RPM and rotating the rotary spindle 222, the grinding feed mechanism 11 is rotated by the grinding unit 21 while the grinding wheel 41 is rotated 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.

  During the grinding process described above, AC power having a predetermined frequency is supplied to the power supply coil 242b of the power supply unit 242 constituting the rotary transformer 24 by the power supply unit 51. As a result, AC power of a predetermined frequency is applied to the ultrasonic vibrator 413 via the rotating power receiving means 241, the conductive wire 25, the concave connector 224, the convex connector 225, and the conductive wire 225a, and the ultrasonic vibrator 413 is supersonic. The sound wave vibrates. This ultrasonic vibration is transmitted to the plurality of grinding wheels 414 via the annular base 412.

  In the grinding wheel 41 according to the first embodiment of the present invention, an opening 412a is formed in the annular base 412, and an annular ultrasonic transducer 413 is disposed surrounding the opening 412a. Has been. In this case, since the opening 412a is formed inside the annular ultrasonic transducer 413, a part of the annular base 412 that defines the opening 412a (the inner portion of the ultrasonic transducer 413) is free. It functions as an end and is more easily deformed than the case where it does not have the opening 412a. Therefore, when AC power is applied from the power supply means 51, the ultrasonic vibrator 413 moves the vertical direction of the grinding wheel 41 (the axial direction of the rotating spindle 222) and the radial direction (the radial direction of the annular base 412). Vibrates ultrasonically. This ultrasonic vibration is transmitted to the plurality of grinding wheels 414 via the annular base 412, and the grinding wheel 414 ultrasonically vibrates in the vertical direction and the radial direction of the grinding wheel 41.

  As described above, in the grinding wheel 41 according to the first embodiment, the opening 412a is formed in the annular base 412, and the annular ultrasonic transducer 413 is arranged around the opening 412a. Therefore, the annular base 412 can be easily deformed along with the ultrasonic vibration by the ultrasonic vibrator 413, so that the ultrasonic vibration generated from the ultrasonic vibrator 413 is effectively transmitted to the grinding wheel 414. It becomes possible to do. In addition, since the amount of ultrasonic vibration of the ultrasonic transducer 413 can be increased simply by forming the opening 412 a in the annular base 412, the ultrasonic wave generated from the ultrasonic transducer 413 can be generated with a simple configuration. It becomes possible to effectively transmit the sonic vibration to the grinding wheel 414.

  In particular, in the grinding wheel 41 according to the first embodiment, the annular base 412 is mounted on the mount base via the annular side wall 415 set to a thickness dimension that allows ultrasonic vibration by the ultrasonic vibrator 413. Since it is connected to 411, it is possible to suppress transmission of ultrasonic vibration by the ultrasonic vibrator 413 to the mount base 411. As a result, it is possible to suppress the situation where the deformation of the annular base 412 due to the ultrasonic vibration is restricted by the mount base 411 attached to the wheel mount 31, so that the ultrasonic vibration generated from the ultrasonic vibrator 413 is ground. It becomes possible to transmit to the grindstone 414 more effectively.

  Further, in the grinding wheel 41 according to the second embodiment of the present invention, the wall thickness increases from the position corresponding to the outer peripheral portion of the ultrasonic transducer 413 to the annular side wall 415 on the upper surface 412b of the annular base 412. A tapered surface 412d is formed to reduce the thickness. For this reason, since the thickness dimension of a part of the annular base 412 connected to the annular side wall 415 can be made the thinnest, it is accompanied by the ultrasonic vibration by the ultrasonic vibrator 413 as compared with the case of having a uniform thickness dimension. The annular base 412 can be further easily deformed. As a result, the transmission efficiency of the ultrasonic vibration generated from the ultrasonic vibrator 413 to the grinding wheel 414 can be further increased, and the amplitude amount of the ultrasonic vibration in the vertical direction and the radial direction of the grinding wheel 41 can be increased. Is possible.

  When the grinding wheel 414 is ultrasonically vibrated in the vertical direction and the radial direction of the grinding wheel 41 in this way, the grinding debris that remains between the abrasive grains of the grinding wheel 414 generated by grinding and causes clogging is removed. It is fluidized and removed together with the grinding water by the fine vibration acting on 414. Thereby, clogging of the grinding wheel 414 can be prevented, so that grinding can be efficiently performed even when brittle hard materials such as sapphire, silicon nitride, lithium tantalate, and Altic are ground.

  Hereinafter, the amplitude amount of the grinding wheel 414 at the time of ultrasonic vibration of the grinding wheel 41 of the grinding apparatus 1 according to the embodiment of the present invention will be described. FIG. 6 is an explanatory diagram of the amplitude amount of the grinding wheel 414 during ultrasonic vibration of the grinding wheel 41 of the grinding apparatus 1 according to the present embodiment. FIG. 6A shows the amplitude amount of the grinding wheel 414 during ultrasonic vibration of the grinding wheel 41 according to the first example (example corresponding to the first embodiment), and FIG. 6B shows the second example. The amplitude amount of the grinding wheel 414 at the time of ultrasonic vibration of the grinding wheel 41 according to an example (an example corresponding to the second embodiment) is shown.

In the first example, the diameter of the annular base 412 of the grinding wheel 41 was set to 300 mm, and the opening diameter of the opening 412a was set to 30 mm. Moreover, the thickness dimension of the annular side wall 415 was set to 0.5 mm. Further, an ultrasonic vibrator 413 made of lead zirconate titanate (Pb (Zi, Ti) O ₃ ) was formed in an annular shape and adhered to the upper surface 412 b of the annular base 412. Further, a voltage of 50 V was applied to the ultrasonic transducer 413 at a frequency of 28.380 kHz.

  As a result, in the first embodiment, as shown in FIG. 6A, the grinding wheel 414 is ultrasonically vibrated with an amplitude of about 2.46 μm in the vertical direction of the grinding wheel 41 (longitudinal direction shown in the figure). 41 was vibrated ultrasonically with an amplitude of around 6.55 μm in the radial direction of 41 (the radial direction shown in the figure).

  In addition, regarding the annular base 412 in which the opening 412a is not formed under the same conditions as in the first embodiment, when a voltage of 50 V is applied to the ultrasonic vibrator 413 at a frequency of 28.920 kHz, the grinding wheel 414 The ultrasonic vibration was performed in the vertical direction of the grinding wheel 41 with an amplitude of approximately 2.08 μm, and the ultrasonic vibration was performed in the radial direction of the grinding wheel 41 with an amplitude of approximately 5.01 μm.

  In the second embodiment, in addition to the first embodiment, the angle of the tapered surface 412d of the upper surface 412b of the annular base 412 is set to 12 degrees. Note that, unlike the first example, a voltage of 50 V was applied to the ultrasonic transducer 413 at a frequency of 20.250 kHz.

  As a result, in the second embodiment, as shown in FIG. 6B, the grinding wheel 414 ultrasonically vibrates with an amplitude of about 2.96 μm in the vertical direction of the grinding wheel 41, and 7.7 in the radial direction of the grinding wheel 41. The ultrasonic vibration was performed with an amplitude of about 26 μm.

  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.

  For example, in the above-described embodiment, the case where the mount base 411 and the annular base 412 constituting the grinding wheel 41 are provided with substantially the same thickness dimension has been described. However, the thickness dimensions of the mount base 411 and the annular base 412 are not limited to this, and may be different thickness dimensions. In relation to the thickness dimension of the annular side wall 415, the ultrasonic vibration from the ultrasonic vibrator 413 is allowed to mount via the annular base 412 and the annular side wall 415 while allowing the ultrasonic vibration by the ultrasonic vibrator 413. It can be set to any thickness dimension on the premise that transmission to the base 411 is suppressed.

  In the second embodiment, the tapered surface 412d is formed on the upper surface 412b of the annular base 412 from the position where the outer periphery of the ultrasonic transducer 413 is disposed to the annular side wall 415. However, the portion of the annular base 412 on which the tapered surface 412d is formed is not limited to this and can be appropriately changed. For example, the tapered surface 412d may be formed on the entire upper surface 412b of the annular base 412 (the portion extending from the portion defining the opening 412a to the annular side wall 415).

  As described above, the present invention grinds ultrasonic vibration generated from an ultrasonic vibrator with a simple configuration when a grinding wheel that performs grinding with ultrasonic vibration is mounted on a wheel mount. It has an effect that it can be effectively transmitted to a grindstone, and can be suitably used as a grinding wheel for grinding brittle hard materials such as sapphire, silicon nitride, lithium tantalate, and Altic.

DESCRIPTION OF SYMBOLS 1 Grinding device 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 22 Spindle unit 221 Spindle housing 222 Rotating spindle 222a Through hole 222b Connector insertion hole 223 Small diameter tip 224 Concave connector 225 Convex connector 225a Conductive wire 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 242a 25 Conductive wire 31 Wheel mount 31a Screw hole 31b Bolt 41 Grinding wheel 41 DESCRIPTION OF SYMBOLS 1 Mount base 411a Opening part 411b Screw hole 412 Annular base 412a Opening part 412b Upper surface 412c Lower surface 412d Tapered surface 413 Ultrasonic vibrator 414 Grinding wheel 415 Annular side wall 51 Power supply means 511 AC power supply 512 Frequency adjustment means 513 Frequency adjustment means 513 Means 514 Control means 515 Input means 516 Control circuit 517 Wiring 518 Wiring

Claims (2)

A grinding wheel mounted on a wheel mount fixed to a spindle tip of a grinding device,
A mount base having an opening at the center and mounted on the wheel mount, a first surface and a second surface opposite to the first surface, wherein a plurality of grinding wheels are outer peripheral portions of the second surface surrounds an annular base having an opening, and an annular side wall which connects the outer peripheral portion and the outer peripheral portion of said annular base of said mounting base, said opening of said annular Jomotodai to and central portion is secured to the And an annular ultrasonic transducer disposed in the center of the first surface.   The first surface of the annular base is formed in a tapered shape whose thickness decreases from the position where the outer periphery of the ultrasonic transducer is disposed to the annular side wall. The grinding wheel according to claim 1.

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