JP2015174180A - ultrasonic chamfering machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic chamfering machine in which any type of grindstone can be used without replacing ultrasonic excitation means in chamfering processing of an outer peripheral part of a workpiece using ultrasonic vibration.SOLUTION: Chamfering processing of an outer peripheral part of a wafer W is performed by bringing the outer peripheral part of the wafer W into contact with a ground groove 110 of a rotating grindstone 108 while rotating the wafer W sucked and held by a suction table 10 around a θ axis. At this time, the chamfering processing is performed while vibrating the wafer W in a θ axis direction by adding ultrasonic vibration to the wafer W by ultrasonic excitation means built in a θ axis shaft 98.

Description

  The present invention relates to an ultrasonic chamfering machine, and in particular, compound semiconductors such as wafers and plates of brittle materials of various shapes, such as sapphire, SiC (silicon carbide), GaN (gallium nitride), and LT (lithium tantalate). The present invention also relates to an ultrasonic chamfering apparatus suitable for chamfering of the outer peripheral portion of an oxide plate.

  A wafer, which is a material of a semiconductor device or an electronic component, is sliced from an ingot state by a slicing device, and then chamfered on the outer peripheral portion in order to prevent the peripheral edge from being cracked or chipped.

  A chamfering machine used for such chamfering processing rotates a grindstone formed with a chamfering groove at a high speed to bring the outer peripheral portion (periphery) of the wafer into contact with the groove of the grindstone, and rotates the wafer. The outer periphery of the wafer is chamfered (see Patent Documents 1 and 2).

  Further, in Patent Document 3, by performing chamfering on the outer peripheral portion of the workpiece while applying ultrasonic vibration to the grindstone, high-precision chamfering, longer life of the grindstone, and high-accuracy due to the grindstone of coarse abrasive grains are performed. It is disclosed that finishing or the like is possible.

Japanese Patent Laid-Open No. 7-156050 JP 2009-142927 A Japanese Patent Laid-Open No. 9-168947

  By the way, the chamfering process using ultrasonic vibration as in Patent Document 3 enables a highly accurate chamfering process without causing cracking or chipping even for a plate-like body (workpiece) of a brittle material, In addition, the processing time can be shortened because high-precision finishing with an abrasive wheel of abrasive grains is possible. Further, the production cost can be reduced by extending the life of the grinding tool, and the work frequency can be reduced because the dressing frequency of the grindstone can be reduced.

  However, when ultrasonic vibration is applied to the grindstone as in Patent Document 3, vibration is difficult to occur because the grindstone is heavy, and in order to give appropriate vibration to the grindstone, the ultrasonic vibration means is applied to the grindstone. It is necessary to output ultrasonic waves of vibration energy. For this reason, there is a problem that the ultrasonic vibration means is increased in size and power consumption.

  In addition, in order to give an appropriate vibration to a grindstone that does not easily vibrate, it is necessary to use ultrasonic vibration means having a characteristic that appropriately corresponds to the type of grindstone (size, thickness, etc. of the grindstone). Therefore, when the type of grindstone is changed according to the type of workpiece to be chamfered, the chamfered shape, etc., it is necessary to replace the ultrasonic vibration means with an appropriate characteristic according to the type of grindstone.

  However, when it is possible to replace the ultrasonic vibration means with an appropriate characteristic according to the type of the grindstone, there is a problem that the cost increases and the number of work steps increases.

  On the other hand, if the ultrasonic vibration means cannot be replaced, the type of grindstone that can properly apply ultrasonic vibration is limited, and the type of chamfering work and the chamfer shape are specified. There is a problem that it is limited to.

  The present invention has been made in view of such circumstances, and in the chamfering process of the outer peripheral portion of the workpiece using ultrasonic vibration, any type of grindstone is used without replacing the ultrasonic vibration means. An object of the present invention is to provide an ultrasonic chamfering machine.

  In order to achieve the above object, an ultrasonic chamfering machine according to the present invention is configured to bring the rotating grindstone into contact with the outer peripheral portion of a rotating plate-like body held by a holding table that rotates around a rotation axis. An ultrasonic chamfering machine for chamfering an outer peripheral portion of a plate-like body, comprising ultrasonic vibration means for adding ultrasonic vibration to the plate-like body when the chamfering is performed.

  According to the present invention, since chamfering is performed by applying ultrasonic vibration to the plate-like body, high-precision chamfering, longer life of the grindstone, high-precision finishing with a rough grindstone, and the like are possible. In addition, even if the type of the grindstone is changed, the plate-like body can be vibrated appropriately without exchanging the ultrasonic vibration means. Therefore, production costs and work man-hours can be reduced.

  In the present invention, it is desirable that the ultrasonic vibration means is configured to vibrate the plate-like body in the direction of the rotation axis.

  Moreover, in this invention, the said ultrasonic vibration means can be made into the aspect integrated in the shaft which transmits the motive power of a motor to the said holding stand.

  In the present invention, the ultrasonic vibration means includes: an ultrasonic vibrator that generates ultrasonic waves; and a horn that increases the amplitude of ultrasonic waves generated by the ultrasonic vibrator and transmits the ultrasonic waves to the holding table. It can be set as the comprised aspect.

  According to the present invention, any type of grindstone can be used without chamfering the ultrasonic vibration means in the chamfering process of the outer peripheral portion of the workpiece using ultrasonic vibration.

The front view which shows the structure of the ultrasonic chamfering machine which concerns on this invention The top view which shows the structure of the ultrasonic chamfering machine which concerns on this invention Partial enlarged view of the complete grinding wheel Partial enlarged view of trapezoidal grinding wheel Partial enlarged view of the total grinding wheel Partial sectional view showing the configuration of ultrasonic vibration means

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 and 2 are a front view and a plan view showing a configuration of an ultrasonic chamfering machine according to the present invention.

  The ultrasonic chamfering machine 50 in the figure uses ultrasonic vibrations to make wafers and plate-like bodies (workpieces) of brittle materials of various shapes such as sapphire, SiC (silicon carbide), GaN (gallium nitride), This is a device for chamfering the outer periphery of a compound semiconductor or oxide workpiece such as LT (lithium tantalate). However, it is not necessarily limited to the plate-like body made of a brittle material, and it is possible to chamfer the outer peripheral portion of the plate-like body made of an arbitrary material. In the following description, it is assumed that the workpiece to be chamfered is a wafer.

  As shown in the figure, the ultrasonic chamfering machine 50 includes a wafer feeding unit 50A and a grinding unit 50B.

  First, the configuration of the wafer feeding unit 50A will be described. A pair of Y-axis guide rails 52 and 52 are laid at a predetermined interval on a horizontally disposed base plate 51. A Y-axis table 56 is slidably supported on the pair of Y-axis guide rails 52, 52 via Y-axis linear guides 54, 54,.

  A nut member 58 is fixed to the lower surface of the Y-axis table 56, and a Y-axis ball screw 60 is screwed to the nut member 58.

  Both ends of the Y-axis ball screw 60 are rotatably supported by bearing members 62 and 62 disposed on the base plate 51 between the pair of Y-axis guide rails 52 and 52. A Y-axis motor 64 is connected.

  Therefore, by driving the Y-axis motor 64, the Y-axis ball screw 60 rotates, and the Y-axis table 56 slides in the horizontal direction (Y-axis direction) along the Y-axis guide rails 52 and 52 via the nut member 58. Moving.

  A pair of X-axis guide rails 66 and 66 are laid on the Y-axis table 56 so as to be orthogonal to the pair of Y-axis guide rails 52 and 52. An X-axis table 70 is slidably supported on the pair of X-axis guide rails 66, 66 via X-axis linear guides 68, 68,.

  A nut member 72 is fixed to the lower surface of the X-axis table 70, and an X-axis ball screw 74 is screwed to the nut member 72.

  Both ends of the X-axis ball screw 74 are rotatably supported by bearing members 76 and 76 disposed on the X-axis table 70 between the pair of X-axis guide rails 66 and 66. An output shaft of an X-axis motor (not shown) is connected to the end.

  Accordingly, by driving the X-axis motor, the X-axis ball screw 74 rotates, and the X-axis table 70 slides in the horizontal direction (X-axis direction) along the X-axis guide rails 66 and 66 via the nut member 72. To do.

  A Z-axis base 80 is erected vertically on the X-axis table 70, and a pair of Z-axis guide rails 82 and 82 are laid on the Z-axis base 80 at a predetermined interval. A Z-axis table 86 is slidably supported by the pair of Z-axis guide rails 82 and 82 via Z-axis linear guides 84 and 84.

  A nut member 88 is fixed to the side surface of the Z-axis table 86 and is screwed to the Z-axis ball screw 90 on the nut member 88.

  Both ends of the Z-axis ball screw 90 are rotatably supported by bearing members 92 and 92 disposed on the Z-axis base 80 between the pair of Z-axis guide rails 82 and 82, and the lower end thereof. The output shaft of the Z-axis motor 94 is connected to the motor.

  Therefore, by driving the Z-axis motor 94, the Z-axis ball screw 90 rotates, and the Z-axis table 86 slides in the vertical direction (Z-axis direction) along the Z-axis guide rails 82 and 82 via the nut member 88. Moving.

  A θ-axis motor 96 is installed on the Z-axis table 86. The output shaft of the θ-axis motor 96 is connected to a θ-axis shaft 98 having a θ-axis (rotation axis θ) parallel to the Z-axis as a center. 10) are connected horizontally.

  The wafer W to be chamfered is placed on the suction table 10 and held by vacuum suction.

  The θ-axis shaft 98 is an ultrasonic vibration means (ultrasonic vibration device) for applying ultrasonic vibration in the θ-axis direction to the wafer W placed on the suction table 10 as will be described in detail later. Consists of. The ultrasonic vibration means applies ultrasonic vibration in the direction of the rotation axis (θ axis) of the θ axis shaft 98 to the wafer W on the suction table 10.

  The ultrasonic wave is defined as, for example, a sound wave having a frequency of 20 kHz or higher, and the ultrasonic vibration unit of the present embodiment outputs an ultrasonic wave having a frequency of 20 kHz to vibrate the wafer W at a frequency of 20 kHz. Let However, the wafer W may be vibrated by ultrasonic waves having a frequency of 20 kHz or higher. In addition, even when the sound wave has a frequency lower than 20 kHz and has the same effect as the ultrasonic chamfering machine 50 of the present embodiment, the wafer W may be vibrated by the sound wave having the frequency. It corresponds to the frequency of the ultrasonic wave in.

  In the wafer feeding unit 50A configured as described above, the suction table 10 moves horizontally in the Y-axis direction in the drawing by driving the Y-axis motor 64, and by driving the X-axis motor in the X-axis direction in the drawing. Move horizontally to. The Z-axis motor 94 is driven to move vertically in the Z-axis direction in the figure, and the θ-axis motor 96 is driven to rotate around the θ-axis.

  Next, the configuration of the grinding unit 50 </ b> B will be described. The gantry 102 is installed on the base plate 51. An outer peripheral motor 104 is installed on the gantry 102, and an outer peripheral spindle 106 having a rotation axis CH parallel to the Z axis as an axis is connected to the output shaft of the outer peripheral motor 104. An outer peripheral grinding wheel 108 (hereinafter simply referred to as a grindstone 108) for chamfering the outer peripheral portion of the wafer W is detachably mounted on the outer peripheral spindle 106, and rotates by driving the outer peripheral motor 104.

  Although a detailed description of the configuration is omitted, as shown in FIG. 2, a nozzle 121 that discharges coolant (grinding fluid) toward a processing point where the wafer W contacts the grindstone 108 is provided.

  Here, the grindstone 108 can be replaced with a desired type according to the type of the wafer (work) to be chamfered, the chamfered shape, and the like. For example, the form (type) of the grindstone 108 shown in FIG. 1 is a so-called general-purpose grindstone, and the same shape as the chamfered shape to be processed into the wafer W is formed on the outer periphery of the grindstone 108 as shown in the partial enlarged view of FIG. The grinding groove 110 is provided. Abrasive grains such as diamond are attached to the grinding groove 110. In the case of the grindstone 108 in this form, the outer peripheral portion (periphery) of the wafer W is brought into contact with the grinding groove 110 so that the outer peripheral portion of the wafer W is chamfered. The shape of the grinding groove 110 varies depending on the chamfered shape.

  Moreover, as shown in the partially enlarged view of FIG. 4, a trapezoidal grindstone having a substantially trapezoidal grinding groove 120 with abrasive grains attached to the outer periphery of the grindstone 108 can be used as the grindstone 108 of another form. Abrasive grains such as diamond are attached to the grinding groove 120. In the case of the grindstone 108 in this form, the upper surface side of the outer peripheral portion of the wafer W is chamfered by bringing the upper surface side of the wafer W into contact with the upper tapered portion 120 a of the grinding groove 120. Further, the lower surface side of the outer peripheral portion of the wafer W is chamfered by bringing the lower surface side of the wafer W into contact with the tapered portion 120 b below the grinding groove 120. The shape of the grinding groove 120 also varies depending on the chamfered shape.

  Furthermore, as another type of grindstone 108, as shown in the partially enlarged view of FIG. 5, a layer type grindstone having a plurality of grinding grooves of the form as in FIG. 3 or FIG. 4 on the outer periphery of the grindstone 108 is used. it can. For example, when there are two grinding grooves 130 and 132 as shown in the figure, one grinding groove is a coarse grinding groove for coarse graining, and the other grinding groove is a grinding groove for fine graining finishing. It can be. However, the use of each grinding groove is arbitrary, and the number of grinding grooves is not limited to two.

  In the ultrasonic chamfering machine 50 configured as described above, the wafer W is chamfered as follows.

  First, as a preparatory step before chamfering, the wafer W to be chamfered is placed on the suction table 10 and sucked and held. Then, the outer peripheral motor 104 and the θ-axis motor 96 are driven to rotate both the grindstone 108 and the suction table 10 at a high speed in the same direction. For example, the rotational speed of the grindstone 108 is set to 3000 rpm, and the rotational speed of the suction table 10 is set to a speed at which the outer peripheral speed of the wafer W is 5 mm / sec.

  Further, the height of the suction table 10 is adjusted by driving the Z-axis motor 94 so that the height of the wafer W corresponds to the height of the grinding groove 110 of the grindstone 108. Further, the X-axis motor is driven so that the θ-axis (rotation axis θ) serving as the rotation axis of the wafer W matches the position of the rotation axis CH of the grindstone 108 in the X-axis direction.

  Further, the ultrasonic vibration means is operated to vibrate the wafer W in the θ-axis direction with ultrasonic waves. For example, the vibration period is 20 kHz as described above.

  Next, as a chamfering process, the Y-axis motor 64 is driven to send the wafer W toward the grindstone 108. And it decelerates just before the outer peripheral part of the wafer W contact | abuts to the grinding groove 110 of the grindstone 108, Then, the wafer W is sent toward the grindstone 108 at low speed. Thereby, while the wafer W vibrates in the rotation axis direction (θ-axis direction), the outer peripheral portion of the wafer W comes into sliding contact with the grinding groove 110 of the grindstone 108 and is ground and chamfered by a minute amount. In addition, coolant is discharged from the nozzle 121 toward the processing point, and at the same time as cooling the processing point, grinding scraps and grinding wheel wear powder (crushed and dropped abrasive grains) are discharged.

  Then, when a predetermined time has passed after the outer peripheral portion of the wafer W reaches the deepest portion of the grinding groove 110, the chamfering process is finished, and the wafer W is moved away from the grindstone 108 and moved to a position where the wafer W is recovered. Let

  Note that the above-described chamfering process is an example, and the chamfering process may be performed by another procedure.

  Next, the ultrasonic vibration means (ultrasonic vibration device) constituting the θ-axis shaft 98 in the wafer feed unit 50A will be described.

  FIG. 6 is a partial cross-sectional view showing the configuration of the ultrasonic vibration means.

  As shown in the figure, the ultrasonic vibration means 150 includes an ultrasonic transducer 152 (ultrasonic transducer unit) and a horn 154 connected to the upper end of the ultrasonic transducer 152.

  The tip of an output shaft (shaft member) (not shown) of the θ-axis motor 96 is connected to the lower end of the ultrasonic vibrator 152, and the table portion 200 having the suction table 10 is detachably attached to the upper end of the horn 154. .

  Further, the ultrasonic transducer 152 and the horn 154 are formed in a cylindrical shape, and their axial centers are arranged coaxially with the θ axis parallel to the vertical direction. As a result, the ultrasonic transducer 152 and the horn 154 constitute the θ-axis shaft 98, and rotate around the θ-axis together with the output shaft of the θ-axis motor 96 by driving the θ-axis motor 96.

  The ultrasonic vibration means 150 (the ultrasonic vibrator 152 and the horn 154) may not constitute the entire θ-axis shaft 98 between the θ-axis motor 96 and the table unit 200, and the θ-axis It can be configured to be incorporated into a part of the shaft 98.

  Further, the ultrasonic vibration means 150 (the ultrasonic vibrator 152 and the horn 154), that is, the θ-axis shaft 98 is rotatably disposed in the lumen of the cylindrical outer cylinder member 160.

  The outer cylinder member 160 is fixed to a fixing member fixed to a Z-axis table 86 (see FIG. 1) such as an outer wall member of the θ-axis motor 96, and the axis of the outer cylinder member 160 is coaxial with the θ-axis. Be placed.

  The upper end portion 160a of the outer cylinder member 160 has an outer diameter reduced and an inner diameter increased, and a flange portion 154a formed on the horn 154 is fitted inside the upper end portion 160a. Then, the cap member 162 is fitted on the upper end portion 160a, and the flange portion 154a is restricted from moving in the vertical direction and the horizontal direction. Thereby, the ultrasonic transducer 152 and the horn 154 are supported by the outer cylinder member 160 so as to be rotatable around the θ axis in a state where movement in the vertical direction and the horizontal direction is restricted.

  The ultrasonic transducer 152 includes a first metal block 170, a piezoelectric element block 172, and a second metal block 174 that are sequentially connected from the lower end side toward the upper end side.

  Although not shown in the figure, the piezoelectric element block 172 is provided with a bolt insertion hole penetrating in the axial direction at the position of the axis (θ axis), and the coupling bolt is inserted into the bolt insertion hole. . Then, both ends of the coupling bolt are screw holes formed in the first metal block and the second metal block. Thus, the first metal block 170 and the second metal block 174 are connected with the piezoelectric element block 172 sandwiched therebetween.

  The first metal block 170 has a connecting portion 170a that is connected to the tip of the output shaft of the θ-axis motor 96 by screw connection or the like at the lower end surface.

  The piezoelectric element block 172 is configured by alternately stacking four piezoelectric elements (first piezoelectric element 172a to fourth piezoelectric element 172d) and four electrodes (first electrode 180a to fourth electrode 180d) in series. .

  The third electrode 180c and the fourth electrode 180d have annular connection portions 182c and 182d extending outward from positions along the outer peripheral surface of the first piezoelectric element 172a to the fourth piezoelectric element 172d.

  The first electrode 180a is connected to the connection portion 182c of the third electrode 180c and set to the same potential as the third electrode 180c, and the connection portion 182c of the third electrode 180c is wired in the lumen of the outer cylinder member 160. The brush at the tip of the formed electric wire 184 is slidably contacted.

  The second electrode 180b is connected to the connection part 182d of the fourth electrode 180d and set to the same potential as the fourth electrode 180d, and the connection part 182d of the fourth electrode 180d is wired in the lumen of the outer cylinder member 160. The brush at the tip of the formed electric wire 185 is slidably contacted.

  An AC voltage having a predetermined frequency and amplitude from an AC voltage supply circuit (not shown) is applied between the electric wires 184 and 185.

  As a result, the AC voltage from the AC voltage supply circuit is applied to each of the first piezoelectric element 172a to the fourth piezoelectric element 172d.

  Each of the first piezoelectric element 172a to the fourth piezoelectric element 172d expands and contracts according to the frequency of the applied AC voltage. As a result, ultrasonic vibration in the axial direction (θ-axis direction) is generated from the piezoelectric element block 172. For example, an AC voltage having a frequency of 20 kHz is applied between the electric wire 184 and the electric wire 185 from the AC voltage supply circuit, and ultrasonic vibration of 20 kHz is generated from the piezoelectric element block 172. Note that the number of piezoelectric elements stacked in the piezoelectric element block 172 is not limited to four.

  The second metal block 174 transmits the ultrasonic vibration generated by the piezoelectric element block 172 to the horn 154.

  A screw hole 174 a that is screwed to the lower end of the horn 154 is formed at the upper end of the second metal block 174.

  The horn 154 is a resonator and increases the amplitude of the ultrasonic vibration transmitted from the second metal block 174 and transmits it to the table unit 200 connected to the upper end.

  A screw portion 154 b is formed to protrude from the lower end surface of the horn 154, and the screw portion 154 b is screwed to the screw hole 174 a of the second metal block 174. As a result, the upper end surface of the second metal block 174, that is, the upper end surface of the ultrasonic transducer 152 and the lower end surface of the horn 154 are joined without gaps, and ultrasonic vibration is transmitted from the second metal block 174 to the horn 154. Is done.

  In addition, a nodal point where the amplitude of the ultrasonic vibration transmitted to the horn 154 is minimized exists near the center of the horn 154 in the axial direction (θ-axis direction). The above-described flange portion 154a whose outer diameter is larger than other portions is formed. The flange portion 154a is held by the upper end portion 160a of the outer cylinder member 160 as described above.

  A connection hole 154 c is formed on the upper end surface of the horn 154 to connect to the connection shaft 202 protruding in a columnar shape of the table unit 200. The connecting shaft 202 of the table portion 200 is formed with a screw portion 202a, and the connecting hole 154c is provided with a screw portion 186 that engages with the screw portion 202a of the connecting shaft 202. Accordingly, the table unit 200 is detachably connected to the upper end of the horn 154, and the ultrasonic vibration transmitted from the ultrasonic transducer 152 to the horn 154 is transmitted to the table unit 200.

  Further, a suction line 188 is formed inside the horn 154, one opening 188 a of the suction line 188 is formed at the bottom of the connection hole 154 c, and the suction line 188 is formed at two locations on the side surface of the horn 154. Openings 188b and 188c are formed.

  The side openings 188 b and 188 c are provided with pipe joints 194 that connect the suction pipes 190 and 192 disposed in the lumen of the outer cylinder member 160 and the suction pipe 188. The pipe joint 194 connects the suction pipe 188 and the suction pipes 190 and 192 at an arbitrary rotation angle around the θ axis of the horn 154.

  A suction device (not shown) is connected to the suction tubes 190 and 192, and the suction device makes the suction tubes 190 and 192 have a negative pressure.

  On the other hand, a suction conduit 204 that communicates from the lower end surface of the connecting shaft 202 to the upper surface of the suction table 10 is formed in the table portion 200. Further, a plurality of grooves 206 are formed on the upper surface of the suction table 10 so as to be continuous with the position of the opening 204 a on the upper surface side of the suction pipe 204. Further, the connection hole 154c of the horn 154 is provided with an O-ring 196 that seals a gap between the connection shaft 202 of the table unit 200 and the wall surface of the connection hole 154c, and air is prevented from flowing through the gap. ing.

  Therefore, when the wafer W is placed on the upper surface of the suction table 10, the suction pipes 190 and 192 are made negative pressure by the suction device, so that the suction pipe 188 and the table unit 200 in the horn 154 are placed. The suction pipe 204 and the groove 206 on the upper surface of the suction table 10 become negative pressure. As a result, a force for sucking the wafer W acts on the upper surface of the suction table 10 and the wafer W is sucked. Then, the ultrasonic vibration transmitted from the horn 154 to the table unit 200 is transmitted to the wafer W, and the wafer W vibrates in the θ-axis direction.

  According to the ultrasonic vibration means 150 described above, when the outer peripheral portion of the wafer W is chamfered by making contact with the grinding groove 110 of the grindstone 108 as shown in FIG. Sonic vibration can be applied.

  Thus, according to the chamfering process using ultrasonic vibration, the following effects can be obtained as compared with the chamfering process not using ultrasonic vibration.

  (1) Since the processing streaks generated on the end surface of the outer peripheral portion of the wafer W are not inclined in the circumferential direction (horizontal direction) but in the oblique direction in the vertical direction (thickness direction of the wafer W), Grinding with less damage is possible. Therefore, the machined surface roughness can be improved. Further, even a grindstone with coarse abrasive grains can be finished and the machining time can be shortened.

  (2) Since the wafer W and the grindstone 108 are always separated from each other at the processing point, the coolant can be effectively supplied to the processing point. Therefore, the life of the grindstone 108 is extended. In addition, the removal of grinding scraps and grinding wheel wear powder (crushed / dropped abrasive grains) from the processing point is improved and clogging is less likely to occur. Can be.

  Further, since the reduction of the grinding force of the grindstone 108 is prevented, the processing speed can be improved, and grinding with a grindstone with fine abrasive grains can be performed, so that the roughness of the work surface can be improved.

  (3) Since not only grinding by rotation of the grindstone 108 but also grinding by vertical movement of the wafer W is performed, the load applied to the grindstone 108 is dispersed. Therefore, the dropping of abrasive grains is greatly reduced. This also contributes to the effect of making it difficult to cause clogging of the grindstone, and makes it possible to reduce the dressing frequency of the grindstone 108 or to eliminate the need for dressing.

  Further, according to the chamfering process in which ultrasonic vibration is applied to the wafer W as in the present embodiment, the following effects are obtained as compared with the chamfering process in which ultrasonic vibration is applied to the grindstone 108.

  (1) The grindstone 108 is heavy, for example, having a weight of about 3 to 4 kg (assuming a grindstone having a diameter of 290 mm and a thickness of about 20 mm). Therefore, it is difficult to appropriately vibrate the grindstone 108 with ultrasonic waves, and in order to vibrate the grindstone 108, the ultrasonic vibration means is designed in consideration of the size (diameter) and thickness of the grindstone 108. There is a need. Therefore, when the grindstone 108 is replaced with a different type, for example, when one grinding groove is replaced as shown in FIG. 3 and a plurality of grinding grooves are replaced as shown in FIG. It is necessary to replace the means with a characteristic corresponding to the type of the grindstone 108.

  On the other hand, the wafer W is light and about several tens of grams (assuming a wafer having a diameter of about 300 mm and a thickness of about several μm). Further, the table portion 200 can also have a weight of about 500 to 600 g, and even when the wafer W and the table portion 200 are combined, it is sufficiently lighter than the grindstone 108. Therefore, it is easier to vibrate the wafer W with ultrasonic waves than the grindstone 108.

  Therefore, when the wafer W is vibrated by ultrasonic waves as in the present embodiment, the ultrasonic vibration means 150 is replaced even when the wafer W and the table unit 200 are replaced with different types. Therefore, the wafer W can be appropriately vibrated with the same thing. Further, even when the grindstone 108 is replaced with a different type, it is not affected at all, so that it is not necessary to replace the ultrasonic vibration means 150.

  From the above, it is possible to reduce production costs and work man-hours. Moreover, the grindstone conventionally used can be used without changing the design.

  (2) As described above, even if the wafer W and the table unit 200 are combined, they are sufficiently lighter than the grindstone 108. Therefore, the vibration energy necessary for vibrating the wafer W is smaller than that when the grindstone 108 is vibrated. Therefore, the ultrasonic vibration means 150 can be reduced, and the apparatus can be reduced in size and power consumption can be reduced.

  DESCRIPTION OF SYMBOLS 10 ... Suction table, 50 ... Ultrasonic chamfering machine, 50A ... Wafer feed unit, 50B ... Grinding unit, 56 ... Y axis table, 70 ... X axis table, 86 ... Z axis table, 96 ... θ axis motor, 98 ... θ Axis shaft, 104 ... outer peripheral motor, 106 ... outer peripheral spindle, 108 ... outer peripheral grinding wheel (grinding stone), 110, 120, 130, 132 ... grinding groove, 121 ... nozzle, 150 ... ultrasonic vibration means, 152 ... ultrasonic vibration Child, 154 ... Horn, 160 ... Outer cylinder member, 162 ... Cap member, 170 ... First metal block, 172 ... Piezoelectric element block, 172a ... First piezoelectric element, 172b ... Second piezoelectric element, 172c ... Third piezoelectric element , 172d, fourth piezoelectric element, 174, second metal block, 200, table portion, 202, connecting shaft, W, wafer.

Claims (4)

An ultrasonic chamfering machine for chamfering the outer peripheral portion of the plate-like body by bringing a rotating grindstone into contact with the outer peripheral portion of the plate-like body rotating and held by a holding table that rotates around a rotation axis. ,
The ultrasonic chamfering machine provided with the ultrasonic vibration means which adds ultrasonic vibration to the said plate-shaped object at the time of implementation of the said chamfering process.   The ultrasonic chamfering machine according to claim 1, wherein the ultrasonic vibration means vibrates the plate-like body in the direction of the rotation axis.   The ultrasonic chamfering machine according to claim 1 or 2, wherein the ultrasonic vibration means is incorporated in a shaft that transmits motor power to the holding table. The ultrasonic vibration means comprises an ultrasonic vibrator that generates ultrasonic waves, and a horn that increases the amplitude of the ultrasonic waves generated by the ultrasonic vibrator and transmits the ultrasonic waves to the holding table. 2. The ultrasonic chamfering machine according to 2 or 3.

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