JP2007111803A - Ultrasonic vibration cutting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic vibration cutting device which can prevent large rolling in a cutting blade. <P>SOLUTION: The ultrasonic vibration cutting device 10 is formed of: a spindle 25; a spindle housing 26 rotatably supporting the spindle 25; a cutting blade 22 having a cutting grindstone portion 23 and a base stand portion 21 supporting the cutting grindstone portion 23, and being fixed to a distal end of the spindle 25; and an vibrator 33 provided for the spindle 25, for generating ultrasonic vibration. The ultrasonic vibration cutting device functions to cut a workpiece 12 by the cutting blade 22 which changes a vibration direction of ultrasonic vibration, transmitted from the vibrator 33 in an axial direction of the spindle 25, into a radial direction of the cutting blade 22, thereby ultrasonically vibrating in the radial direction. Herein a plurality of slits 23a are formed in an external peripheral edge of the cutting grindstone portion 23 of the cutting blade 22, and therefore rolling of the cutting grindstone portion 23, especially large rolling of the cutting grindstone portion 23, occurring when a radial length h of the cutting grindstone portion 23 is in excess of about 20 times a blade thickness t, can be prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic vibration cutting device, and more particularly to a configuration of a cutting blade of an ultrasonic vibration cutting device.

  In order to divide a semiconductor wafer into chips, there is known a dicing apparatus that cuts a semiconductor wafer with a cutting blade composed of a cutting grindstone portion and a base portion. In such a dicing apparatus, it is a continuous problem to suppress the temperature rise at the processing point and to reduce chipping without increasing the cutting resistance. As a means for solving such a problem, for example, it has been studied to cut a semiconductor wafer by using ultrasonic vibration having a sound range (approximately 20 KHz or more) higher than a human audible frequency.

  For example, Patent Document 1 discloses cutting a semiconductor wafer by ultrasonically vibrating a cutting blade. In such a method, the cutting blade is bent in the thickness direction by ultrasonic vibration. For this reason, a force that widens the cutting groove of the semiconductor wafer is exerted by the ultrasonically oscillating cutting blade, which inevitably increases the cutting resistance and causes chipping.

  As a method for solving such a problem, Patent Document 2 discloses that the ultrasonic vibration is transmitted in the direction of the rotation axis to which the cutting blade is attached, and the cutting blade is moved in the radial direction by the vibration transmission direction changing portion attached together with the cutting blade. There has been proposed a cutting device that vibrates in a straight line.

  By cutting the semiconductor wafer with such a ultrasonically oscillated cutting blade, the cutting resistance can be reduced as compared with the cutting with a normal cutting blade, so that chipping can be suppressed. In addition, since cutting water is easily supplied to the processing point, the processing temperature does not rise and distortion due to heat does not occur. Further, since the contamination attached to the cutting blade due to vibration is shaken off, the contamination does not adhere to the cutting blade. In addition, there is an advantage that the load on the cutting blade is reduced and the life of the cutting blade is extended.

  In such an ultrasonic vibration device, the shape and size of the cutting blade, the diameter and length of the spindle, or the ultrasonic vibrator is used to vibrate the cutting blade in the radial direction by the vibration transmission direction changing unit attached together with the cutting blade. In addition to this output, it is necessary to accurately arrange the cutting blade and ultrasonic transducer to the position where they are attached to the spindle.

  In the above ultrasonic vibration cutting apparatus, the minimum amplitude point of the vibration waveform transmitted from the ultrasonic vibrator is set as the vibration transmission direction conversion point, and the cutting blade is disposed at the same position as or near the vibration transmission direction conversion point. ing. At this vibration transmission direction conversion point, the transmission direction of ultrasonic vibration is converted from the axial direction of the spindle to the radial direction of the cutting blade. Thus, the blade diameter of the cutting blade and the ultrasonic wave are set such that the maximum vibration amplitude point in the vibration waveform of the ultrasonic vibration converted from the transmission direction of the ultrasonic vibration into the radial direction of the cutting blade is located at the cutting edge of the cutting blade. The frequency of vibration is adjusted. Therefore, the cutting edge of the cutting blade is arranged so as to vibrate ultrasonically only in the radial direction.

JP 2002-336775 A JP 2000-210928 A JP 2002-66934 A

  However, as a result of verification by the present inventors, even if the cutting edge position of the cutting blade is ideally arranged at a position where ultrasonic vibration is performed only in the radial direction, the thickness that is perpendicular to the radial direction of the cutting blade It became clear that a large vibration (lateral vibration) was generated in the direction, and the width of the cut groove of the cut semiconductor wafer was increased. This is because if the cutting wheel has a continuous shape in the circumferential direction, depending on the length and thickness of the cutting edge of the cutting blade, when the cutting blade is vibrated ultrasonically, the cutting wheel of the cutting blade has a diameter. It is considered that the cutting grindstone portion is bent in the thickness direction by being deformed so as to expand in the direction.

  The inventors of the present application have found that the lateral runout of the cutting grindstone varies greatly depending on the structure of the cutting blade. That is, in the ultrasonic vibration cutting blade in which the cutting wheel portion and the base portion are integrally formed, the radial length h of the cutting wheel portion protruding from the outer periphery of the base portion is the thickness of the cutting wheel portion. It has been found that when the blade thickness is about 20 times or more of t (that is, h / t> 20), a large lateral shake occurs abruptly.

  For example, a cutting blade for ultrasonic vibration comprising a base portion having a diameter of 3 inches and a cutting wheel portion having a radial length h of about 2.0 mm and a blade thickness t of about 60 μm protruding from the base portion. Is used, the radial length h of the protruding cutting wheel portion is about 33 times the blade thickness t. At this time, a lateral runout of about 60 μm occurs on both sides in the thickness direction of the cutting grindstone, and the width of the cutting groove is increased about twice.

  On the other hand, if the length h of the protruding cutting grindstone portion is about 20 times or less of the blade thickness t (that is, h / t ≦ 20), the side runout of the cutting blade is about 3 μm, and cutting that occurs during normal cutting It is about the same size as the blade runout. Therefore, a lateral runout that increases the width of the cutting groove does not occur. However, when it is necessary to form a cutting groove with a small cutting width and a deep cutting depth with respect to the work piece, the radial length h protruding from the base portion of the cutting grindstone is the cutting length. It may be about 20 times or more the blade thickness t of the grindstone. In such a case, there was a problem that ultrasonic vibration cutting with high accuracy could not be performed.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a new and improved superstructure capable of preventing the occurrence of a large lateral runout in a cutting blade. The object is to provide a sonic vibration cutting device.

  In order to solve the above-described problems, according to one aspect of the present invention, a spindle includes a spindle, a spindle housing that rotatably supports the spindle, a cutting wheel portion, and a base portion that supports the cutting wheel portion. A cutting blade fixed to the tip of the blade and a vibrator that is provided on the spindle and ultrasonically vibrates, and the vibration direction of the ultrasonic vibration transmitted from the vibrator in the axial direction of the spindle is the radial direction of the cutting blade There is provided an ultrasonic vibration cutting apparatus that converts a workpiece into a workpiece by a cutting blade that ultrasonically vibrates in the radial direction. A plurality of slits are formed in the outer peripheral portion of the cutting wheel portion of the cutting blade.

  In the ultrasonic vibration cutting machine, when the cutting blade vibrates in the radial direction, depending on the shape of the cutting blade, the cutting wheel of the cutting blade is deformed so as to expand in the radial direction. End up. Therefore, by forming a plurality of slits on the outer periphery of the cutting grindstone, the bending of the cutting grindstone is blocked from being transmitted in the circumferential direction, and a large lateral vibration occurs in the thickness direction of the cutting grindstone. Can be prevented.

  Here, when the cutting blade has a radial length of the cutting wheel portion protruding from the outer periphery of the base portion as h, and a thickness (blade thickness) of the cutting wheel portion as t, a relationship of h / t> 20. When satisfying, a plurality of slits are formed in the cutting wheel portion of the cutting blade. When the radial length h of the cutting wheel portion protruding from the outer periphery of the base portion exceeds 20 times the blade thickness t of the cutting wheel portion, the inventors of the present invention I found out that the runout suddenly increased. Therefore, if a plurality of slits are formed in the outer peripheral portion of the cutting grindstone when at least the relationship of h / t> 20 is satisfied, it is possible to prevent a large lateral runout occurring in the cutting grindstone.

  As described above, according to the present invention, it is possible to provide an ultrasonic vibration cutting device capable of preventing the occurrence of large lateral vibration in the cutting blade.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
First, based on FIG. 1, the whole structure of the cutting device 10 comprised as an example of the ultrasonic vibration cutting device concerning the 1st Embodiment of this invention is demonstrated. FIG. 1 is an overall perspective view showing the cutting apparatus 10 according to the present embodiment.

  As shown in FIG. 1, a cutting apparatus 10 includes, for example, a cutting unit 20 that cuts a workpiece 12 such as a semiconductor wafer, a chuck table 15 that is an example of a holding unit that holds the workpiece 12, and a cutting device. A unit moving mechanism (not shown) and a chuck table moving mechanism (not shown) are provided.

  The cutting unit 20 includes a cutting blade 22 attached to a spindle. The cutting unit 20 cuts the workpiece 12 by cutting the workpiece 12 by rotating the cutting blade 22 that vibrates ultrasonically in the radial direction at a high speed, thereby cutting the workpiece 12 into an extremely thin kerf (cutting piece). Groove) can be formed.

  Further, the chuck table 15 is, for example, a disk-shaped table having a substantially flat upper surface, and is provided with a vacuum chuck (not shown) on the upper surface. For example, the workpiece 12 supported by the frame 14 via the dicing tape 13 is placed on the chuck table 15, and the workpiece 12 can be vacuum-sucked and stably held.

  The cutting unit moving mechanism moves the cutting unit 20 in the Y-axis direction. The Y-axis direction is a horizontal direction orthogonal to the cutting direction (X-axis direction), and is, for example, the axial direction of a spindle disposed in the cutting unit 20. By such movement in the Y-axis direction, the cutting edge of the cutting blade can be aligned with the cutting position (cutting line) of the workpiece 12. The cutting unit moving mechanism also moves the cutting unit 20 in the Z-axis direction (vertical direction). Thereby, the cutting depth of the cutting blade 22 with respect to the workpiece 12 can be adjusted, or contact setup for detecting the reference position of the cutting blade 22 can be executed.

  During normal dicing, the chuck table moving mechanism reciprocates the chuck table 15 holding the workpiece 12 in the cutting direction (X-axis direction) and feeds the cutting table 22 to the workpiece 12. The cutting edge is operated with a linear trajectory.

  The cutting apparatus 10 having such a configuration cuts the workpiece 12 into a lattice by moving the cutting unit 20 and the chuck table 15 relative to each other while cutting the cutting blade 22 rotating at a high speed into the workpiece 12. That is, dicing can be performed.

  Next, a schematic configuration of the cutting unit 20 according to the present embodiment will be described based on FIG. FIG. 2 is a perspective view showing the cutting unit 20 according to the present embodiment.

  As shown in FIG. 2, the cutting unit 20 includes, for example, a cutting blade 22 in which a cutting grindstone portion 23 and a base portion 21 are integrally formed, a spindle 25 on which the cutting blade 22 is mounted at a tip portion, and a spindle 25 Is mainly provided with a spindle housing 26 that rotatably supports a cutting water supply nozzle 27, a foil cover 28, a bolt 29, and an adjustment member 40.

  The cutting blade 22 is a hub blade in which an extremely thin cutting grindstone portion 23 having a substantially ring shape and a base portion 21 that supports the cutting grindstone portion 23 are integrally configured. The base portion 21 is formed by molding a conductive material such as a metal material such as aluminum. The cutting grindstone portion 23 is formed, for example, by electrodepositing abrasive grains such as diamond on the base portion 21, and is disposed on the outer periphery of the cutting blade 22. As described above, since the base portion 21 and the cutting grindstone portion 23 are integrally formed, there is no gap between them, so that the structure is suitable for transmission of ultrasonic vibration.

  The cutting blade 22 is attached to the tip portion (not shown) of the spindle 25 by, for example, a bolt 29. At this time, the substantially cylindrical adjustment member 40 is also attached to one side of the cutting blade 22. Details of the mounting mechanism of the cutting blade 22 and the adjustment member 40 will be described later (see FIG. 3).

  The spindle 25 is a rotating shaft for transmitting a rotational driving force of a motor (not shown), which will be described later, to the cutting blade 22, for example, and rotates the mounted cutting blade 22 at a high speed of, for example, 30,000 rpm. . Most of the spindle 25 is covered with a spindle housing 26, but its tip is exposed from the spindle housing 26, and a cutting blade 22 is attached to the tip.

  The spindle housing 26 is a housing provided so as to cover the spindle 25. The spindle housing 26 can support the spindle 25 so as to be capable of high-speed rotation by an air bearing provided therein, and details thereof will be described later (see FIG. 3).

  The cutting water supply nozzle 27 is detachably provided on both sides of the cutting blade 22, for example, and supplies cutting water to the side surface of the cutting blade 22 and the vicinity of the processing point to cool it. Further, the foil cover 28 is provided so as to cover the outer periphery of the cutting blade 22 and protects the cutting blade 22 and prevents scattering of cutting water and cutting debris.

  The cutting unit 20 having such a configuration rotates the cutting blade 22 at a high speed by the spindle 25, and cuts the cutting grindstone portion 23 of the cutting blade 22 into the workpiece 12 so as to relatively move. Thereby, for example, the processing surface of the workpiece 12 can be cut and an extremely thin kerf can be formed along the cutting line.

  Next, based on FIG. 3, the internal structure of the spindle housing 26 according to the present embodiment and the mounting mechanism of the cutting blade 22 will be described in detail. FIG. 3 is a longitudinal sectional view showing an internal configuration of the spindle housing 26 in the cutting unit 20 according to the present embodiment.

  As shown in FIG. 3, the spindle housing 26 of the cutting unit 20 includes, for example, a spindle 25, a radial air bearing 30 and a thrust air bearing 31 that rotatably support the spindle 25, a radial air bearing 30 and a thrust. An air supply path (not shown) for supplying high-pressure air to the air bearing 31, and an exhaust path (not shown) for discharging the air ejected by the radial air bearing 30 and the thrust air bearing 31. , A motor 32 having a rotor 32a and a stator 32b, a stator power supply 34 for supplying electric power to the stator 32b, and, for example, a PZT vibrator 33 as an ultrasonic vibrator provided on the rear end side of the spindle 25. And non-contact supply for supplying power to the PZT vibrator 33 A device 35, is provided.

  Specifically, a rotor 32 a that is a rotating shaft constituting the motor 32 is provided on the rear side of the spindle 25. When electric power is supplied to the stator 32b by the stator power supply unit 34, a rotational driving force is generated by the interaction of the rotor 32a and the stator 32b, and the spindle 25 is rotated at a high speed by this rotational driving force. Further, a thrust plate 25 a having a diameter larger than the shaft diameter of the spindle 25 is provided on the tip end side of the spindle 25.

  Further, the radial air bearing 30 supports the spindle 25 rotating at high speed in the radial direction (XZ plane direction) by air pressure by ejecting air toward the outer periphery of the spindle 25. On the other hand, the thrust air bearing 31 supports the spindle 25 rotating at high speed in the thrust direction (Y-axis direction) by jetting air to the thrust plate 25a.

  The spindle 25, the spindle housing 26, the radial air bearing 30, the thrust air bearing 31, the motor 32 and the like constitute an air spindle mechanism and can support the spindle 25 rotating at high speed in a non-contact manner.

  In addition, the spindle 25 is provided with, for example, a PZT vibrator 33 that is an electrostrictive vibrator and a non-contact power feeding device 35 that supplies power to the PZT vibrator 33 as ultrasonic vibrators.

  For example, the PZT vibrator 33 is disposed on the rear side of the spindle 25 (on the side opposite to the cutting blade 22) further on the rear side than the rotor 32a. The PZT vibrator 33 is a bolted Langevin vibrator made of a piezoelectric ceramic material such as lead zirconate titanate (PZT). The vibrator is not limited to the example of the electrostrictive vibrator, and for example, a magnetostrictive vibrator can be used.

  The non-contact power feeding device 35 includes a primary transformer 51 that is a power-feeding transformer disposed on the inner peripheral surface of the spindle housing 26 and a secondary power-receiving transformer that is disposed at the rear end of the spindle 25. The power supply terminal 53 is connected to the side transformer 52, an external power source (not shown), and the primary side transformer 51. The non-contact power feeding device 35 configured as described above transmits the power supplied from the external power source via the power feeding terminal 53 to the secondary-side transformer 52 from the primary-side transformer 51 in a non-contact manner by an electromagnetic induction method. Is supplied to the PZT vibrator 33. By supplying power to the PZT vibrator 33 in a non-contact manner by the non-contact power supply device 35, it is not necessary to bring a power supply member into contact with the spindle 25, so that the spindle 25 can rotate smoothly and take advantage of the air spindle mechanism. be able to.

  Thus, the PZT vibrator 33 generates ultrasonic vibrations by the electric power supplied from the non-contact power supply device 35 to ultrasonically vibrate the spindle 25. This ultrasonic vibration is transmitted in the axial direction of the spindle 25 (Y-axis direction) and travels toward the cutting blade 22 attached to the tip 24 of the spindle 25. Furthermore, the ultrasonic vibration transmitted in the axial direction (Y-axis direction) of the spindle 25 in this way is converted into the radial direction (XZ plane direction) of the cutting blade 22. The structure of the mounting mechanism of the cutting blade 22 and the frequency of the PZT vibrator 33 so that the Y-axis position of this vibration transmission direction conversion point is the same as or close to the Y-axis position of the cutting wheel portion 23 of the cutting blade 22. Etc. have been adjusted.

  Here, the structure of the mounting mechanism of the cutting blade 22 according to the present embodiment will be described in detail with reference to FIG.

  As shown in FIG. 3, the cutting blade 22 according to the present embodiment has a configuration in which the base portion 21 and the cutting grindstone portion 23 that is electrodeposited on the base portion 21 are integrated as described above. is there. On both sides of the base portion 21 of the cutting blade 22, columnar first joint portions 21 a and second joint portions 21 b having substantially the same diameter as the tip portion 24 of the spindle 25 are respectively projected. The end surface of the first joint portion 21a (the flat surface at the left end of the base portion 21 in FIG. 3) becomes the first joint surface with the adjustment member 40, and the end surface of the second joint portion 21b (the base portion in FIG. 3). The flat surface at the right end of 21 is the second joint surface with the tip 24 of the spindle 25. The shapes of the first and second joining surfaces are circular with substantially the same diameter as the joining surface of the tip portion 24 of the spindle 25.

  Further, a base part through hole 21 c is formed through the base part 21 of the cutting blade 22 in the axial direction of the spindle 25. The base part through hole 21c has a larger diameter than a bolt body part 29b of a bolt 29 described later, and when the bolt body part 29b is inserted into the base part through hole 21c, both are in a non-contact state. It comes to become.

  The adjustment member 40 is a member formed by molding a metal material such as aluminum, for example, and has a cylindrical shape corresponding to the tip portion 24 of the spindle 25. The outer diameter of the cylindrical adjustment member 40 is adjusted to be substantially the same as the outer diameter of the first joint portion 21 a of the base portion 21 of the cutting blade 22. The adjusting member 40 is joined to the first joint surface of the first joint portion 21a of the base portion 21.

  The adjusting member 40 having such a structure is used for adjusting the vibration state of the ultrasonic vibration according to the frequency of the ultrasonic vibration transmitted from the spindle 25 in the axial direction. Specifically, the adjustment member 40 is configured such that the ultrasonic vibration transmitted in the axial direction is a maximum vibration amplitude point, that is, a vibration transmission direction conversion point, at the axial end portion (left end portion in FIG. 3) of the adjustment member 40. To a point at a distance of a quarter wavelength of the ultrasonic vibration (see FIG. 4).

  The bolt 29 includes a bolt head portion 29a that engages with the adjustment member 40, and a bolt body portion 29b that has an external thread formed on the outer periphery. The diameter of the bolt head portion 29a is a size that can be engaged with the adjusting member 40, and is adjusted to be larger than the diameter of the base portion through hole 21c of the cutting blade 22. On the other hand, the diameter of the bolt body 29b is adjusted to be smaller than the diameter of the base part through hole 21c. Further, the bolt body 29b is screwed into a female screw hole 24a formed in the tip 24 of the spindle 25.

  With the bolt 29 having such a configuration, the adjustment member 40, the base portion 21 of the cutting blade 22, and the tip portion 24 of the spindle 25 are joined together, and the cutting blade 22 and the adjustment member 40 are connected to the tip portion 24 of the spindle 25. Can be attached and fixed to. At this time, the bolt head portion 29a locks the adjusting member 40, and the bolt body portion 29b passes through the base portion through hole 21c of the cutting blade 22 in a non-contact state and is screwed into the tip portion 24 of the spindle 25. Match.

  Further, at the time of such joining, a first contact ring 51 as an example of a first contact member is sandwiched between the joint surface of the adjustment member 40 and the first joint surface of the base portion 21 of the cutting blade 22. It is. On the other hand, a second contact ring 52, which is an example of a second contact member, is sandwiched between the second joint surface of the base portion 21 of the cutting blade 22 and the tip portion 24 of the spindle 25. The first contact ring 51 and the second contact ring 52 are ring-shaped uneven absorption members formed of, for example, an insulating soft material such as soft resin or paper.

  The outline of the internal configuration of the cutting unit 20 according to the present embodiment and the mounting mechanism of the cutting blade 22 has been described above with reference to FIG. With the configuration as described above, the tip portion 24 of the spindle 25, the base portion 21 of the cutting blade 22, and the adjusting member 40 can be suitably joined together without any gaps, and a state close to an integrated configuration can be achieved. Further, the ultrasonic vibration generated by the PZT vibrator 33 is transmitted in the axial direction of the spindle 25, and the transmission direction of the transmitted ultrasonic vibration is changed at the vibration transmission direction conversion point at substantially the same position as the cutting blade 22. Conversion to the radial direction of the cutting blade 22 is possible. As a result, while the cutting blade 22 is ultrasonically vibrated in the radial direction, that is, while the ring-shaped cutting grindstone portion 23 is vibrated so as to repeatedly expand and contract at a high frequency, the workpiece 12 is processed by the cutting blade 22. Can be cut.

  The principle of ultrasonically vibrating the cutting blade 22 in the radial direction as described above is described in, for example, the above-mentioned Patent Document 2 and is well known, but will be briefly described below with reference to FIG.

  FIG. 4 is an explanatory diagram showing a vibration waveform W1 that resonates with ultrasonic vibration from the PZT vibrator 33 and a vibration waveform W2 in which the transmission direction is converted to the radial direction in the cutting unit 20 according to the present embodiment. . The vibration waveform W1 represents the instantaneous displacement (vibration amplitude) of the ultrasonic vibration due to resonance, and the vibration waveform W2 represents the instantaneous displacement (vibration amplitude) of the ultrasonic vibration whose transmission direction is converted to the radial direction. .

  As shown in FIG. 4, the maximum vibration amplitude points A, C, E, and G and the minimum vibration amplitude points B, D, F, and H of the vibration waveform W1 exist on the axis of the spindle 25 (on the Y axis). To do. Usually, at the minimum vibration amplitude points B, D, F, and H, the radial extension of the spindle 25 is maximized. Accordingly, the distance between the spindle 25 and the spindle housing 26 must be larger than the maximum diameter expansion amount of the spindle 25 at least at the minimum vibration amplitude points B, D, F, and H. However, with respect to other points, since the cutting unit 20 employs an air spindle mechanism, the vicinity of the minimum vibration amplitude points B, D, F, and H is structurally reinforced as in the case where a mechanical spindle mechanism is employed. There is no need to

  The minimum vibration amplitude point B of the vibration waveform W1 is a vibration transmission direction conversion point, and the cutting grindstone portion 23 of the cutting blade 22 is disposed at the Y-axis position that is the same as or close to the vibration transmission direction conversion point B. . At the vibration transmission direction conversion point B, the transmission direction of ultrasonic vibration is converted from the axial direction of the spindle 25 (Y-axis direction) to the radial direction of the cutting blade 22 (XZ plane direction). The blade diameter of the cutting blade 22 and the ultrasonic vibration are set so that the maximum vibration amplitude points α and β in the vibration waveform W2 of the ultrasonic vibration whose transmission direction is converted to the radial direction are positioned at the cutting edge position of the cutting blade. The frequency is adjusted.

  Further, in order to suitably transmit and convert the ultrasonic vibration, the cutting wheel portion 23 and the base portion 21 of the cutting blade 22 are integrally configured as described above, and the adjustment member 40 and the cutting blade are integrated. The base portion 21 of the 22 and the tip portion 24 of the spindle 25 are configured to be firmly fixed to each other through a first contact ring 51 and a second contact ring 52. Further, the base portion 21 of the cutting blade 22 is shaped so as to be symmetrical in the Y-axis direction with the vibration transmission direction conversion point B as the center, and the maximum vibration amplitude point A is determined by the adjustment member 40. Located at the tip.

  As described above, by changing the transmission direction of the ultrasonic vibration transmitted through the spindle 25 in the axial direction to the radial direction, the cutting wheel portion 23 of the cutting blade 22 repeatedly expands and contracts, and the cutting edge thereof Is suitably ultrasonically vibrated in the radial direction.

  Here, even if the position of the cutting edge of the cutting blade 22 is ideally disposed at a position where ultrasonic vibration is performed only in the radial direction, the thickness is perpendicular to the radial direction of the cutting blade 22 depending on the shape of the cutting blade 22. A large vibration (lateral runout) occurs in the direction, causing a problem that the width of the cut groove of the cut workpiece 12 is widened. This is because, if the cutting grindstone portion 23 has a continuous shape in the circumferential direction, depending on the length and thickness of the cutting edge of the cutting blade 22, when the cutting blade 22 is ultrasonically vibrated, the cutting blade 22 is cut. It is considered that the grinding wheel portion 23 is bent in the thickness direction by deforming the grinding wheel portion 23 so as to expand in the radial direction.

  The inventors of the present application have found through experiments that this lateral runout varies greatly depending on the structure of the cutting blade 22. That is, in the ultrasonic vibration cutting blade 22 in which the cutting grindstone portion 23 and the base portion 21 are integrally formed, the radial length h (hereinafter, referred to as the cutting grindstone portion 23 protruding from the outer periphery of the base portion 21). When “the length h of the cutting edge of the cutting wheel portion 23” is about 20 times or more the thickness t of the cutting wheel portion 23 (hereinafter referred to as “the blade thickness t”), that is, h / t> 20, It was found that a large lateral shake occurred suddenly.

  In this experiment, with respect to the cutting grindstone portion 23 having a blade thickness t of about 50 μm fixed to the 3-inch base portion 21, the length of the cutting edge of the cutting grindstone portion 23 is changed. The lateral runout of the blade edge was measured. At this time, a plurality of cutting blades 22 each having a cutting edge length h of the cutting grindstone 23 different every 100 μm were prepared, and the lateral deflection of the cutting edge was measured for each. In such measurement, while the cutting blade 22 is stationary, for example, a power of about 30 W is applied to the PZT vibrator 33 and oscillated at a frequency of 55 kHz, and ultrasonically vibrated in the radial direction (the direction of arrow R in FIG. 5). Then, the magnitude L (runout in the direction of arrow L in FIG. 5) of the lateral runout of the cutting grindstone 23 at the measurement location in FIG. 5 was measured. The lateral vibration magnitude L of the cutting grindstone portion 23 can be measured using, for example, a laser measuring device, and the laser is applied from the direction perpendicular to the ultrasonic vibration direction (radial direction) of the cutting grindstone portion 23. By irradiating the cutting edge (measurement location in FIG. 5) of the cutting grindstone 23, the lateral runout of the cutting grindstone 23 can be measured.

  A graph showing the relationship between the length h of the cutting edge of the cutting grindstone 23 and the magnitude L of the lateral runout of the cutting grindstone 23 obtained by the above experiment is shown in FIG. According to such an experiment, as shown in FIG. 6, the lateral vibration magnitude L of the cutting grindstone portion 23 was about 3 μm or less until the length h of the cutting edge of the cutting grindstone portion 23 was about 1000 μm. It has been clarified that when the length h of the cutting edge exceeds about 1000 μm, the lateral runout of the cutting grindstone portion 23 suddenly increases. That is, when the length h of the cutting edge of the cutting grindstone 23 exceeds about 20 times the blade thickness t (when the relationship of h / t> 20 is established), it is found that the lateral runout becomes large with a normal cutting blade. did.

  Although the magnitude of the radial amplitude varies depending on the magnitude of the electric power applied to the PZT vibrator 33, it is considered that the magnitude of the lateral runout is somewhat affected. When the blade thickness exceeds about 20 times the blade thickness t (when the relationship of h / t> 20 is established), the horizontal runout remains unchanged with a normal cutting blade. Further, the amplitude when the cutting blade 22 is ultrasonically oscillated is generally set to about 5 to 6 μm, but the power applied to the PZT vibrator 33 is set to about 30 W so that the amplitude is set in this range. Can do.

  In the cutting apparatus 10 according to the present embodiment, a plurality of slits are formed in the cutting grindstone portion 23 of the cutting blade 22 in order to prevent a large lateral vibration from occurring in the cutting grindstone portion 23. Below, based on FIG. 7, the structure of the cutting blade 22 concerning this embodiment is demonstrated. Here, Fig.7 (a) is a front view which shows the cutting blade 22 concerning this embodiment, and FIG.7 (b) is a side view which shows the cutting blade 22 concerning this embodiment.

  As shown in FIG. 7A, a plurality of slits, for example, eight slits 23a are formed at equal intervals in the cutting wheel portion 23 of the cutting blade 22 according to the present embodiment. At least two slits 23a are formed. However, if the number of the slits 23a or the ratio of the slits 23a in the entire cutting wheel portion 23 is too large, the cutting ability is deteriorated. Therefore, the slits depend on the balance between the cutting conditions (cutting ability) and the side wobbling of the cutting wheel portion. The number of 23a is determined.

  The slit 23a is formed so as to be divided so as not to bend in the thickness direction when the cutting edge of the cutting grindstone 23 is ultrasonically vibrated, and the depth and width of the slit 23a are limited. Is not to be done. For example, when using a cutting blade 22 having a size of the base portion 21 of 3 inches, a cutting edge length h of the cutting grindstone portion 23 of about 2.0 mm, and a blade thickness of about 60 μm, the depth of the slit 23a The length (the length along the radial direction of the cutting grindstone portion 23) can be about 1.0 to 2.0 mm, and the width can be about 0.1 to 1.0 mm.

  By forming such a slit 23 a, it is possible to prevent the bending of the cutting grindstone portion 23 from being transmitted in the circumferential direction, and to prevent a large lateral vibration from occurring in the thickness direction of the cutting grindstone portion 23.

  The slit 23a functions particularly effectively when a relationship of h / t> 20 is established between the radial length h of the cutting grindstone portion 23 protruding from the outer periphery of the base portion 21 and the blade thickness t. . As described above, when the length h of the cutting edge of the cutting wheel portion 23 exceeds about 20 times the blade thickness t, that is, when the relationship of h / t> 20 is established, the side wobbling of the cutting wheel portion 23 is abrupt. Therefore, it becomes difficult to perform highly accurate machining. Therefore, by forming a plurality of slits 23a in the cutting grindstone portion 23, the lateral runout of the cutting grindstone portion 23 can be reduced. For example, the cut width is small with respect to the work piece 12 and the cut depth is reduced. It is also possible to form deep cutting grooves.

  The configuration of the cutting blade 22 according to the present embodiment has been described above. Next, in order to verify the effect of preventing the side wobbling of the cutting grindstone portion 23 by forming a plurality of slits 23a in the cutting grindstone portion 23 of the cutting blade 22, a comparative experiment was performed. Hereinafter, a comparative experiment will be described with reference to FIG.

(Comparative experiment)
In the comparative experiment, an ordinary cutting blade 22 having no slit 23a shown in FIG. 8A and a cutting blade 22 having the slit 23a according to the present embodiment shown in FIG. 8B are shown. The magnitude of the lateral runout of the cutting wheel portion 23 was measured and compared. The used cutting blades 22 are cutting blades 22 each having a base portion 21 having a size of 3 inches, the cutting edge length h of the cutting wheel portion 23 is about 2 mm, and the cutting thickness t of the cutting wheel portion 23 is about 60 μm. Met. Then, eight slits 23a having a depth of about 2 mm and a width of about 1 mm were formed at equal intervals only in the cutting grindstone portion 23 of the cutting blade 22 shown in FIG.

  In this comparative experiment, the cutting stones at the four measurement points A to D of the cutting blade 22 shown in FIG. 8A and the four measurement points A ′ to D ′ of the cutting blade 22 shown in FIG. The radial runout and lateral runout of the portion 23 were measured. Such a measurement was performed using a laser measuring apparatus that measures the distance by irradiating each measurement point with a laser. The measurement results are shown in Tables 1 and 2 below. Table 1 shows the measurement results for the cutting blade 22 shown in FIG. 8A, and Table 2 shows the measurement results for the cutting blade 22 shown in FIG. 8B.

  As shown in Table 1, the average value of the radial runout of the cutting grindstone portion 23 in the conventional cutting blade 22 shown in FIG. 8A is about 5.2 μm, and the average value of the lateral runout of the cutting grindstone portion 23 is shown. Was about 67.5 μm. On the other hand, as shown in Table 2, the average value of radial runout of the cutting wheel portion 23 in the cutting blade 22 in which the slit 23a shown in FIG. 8B is formed is about 5.225 μm, and the cutting wheel portion 23 The average value of the horizontal runout was about 2.35 μm.

  Thus, in the two cutting blades 22 shown in FIGS. 8 (a) and 8 (b), the radial wobbling of the cutting grindstone 23 is substantially the same, but the conventional cutting shown in FIG. In the blade 22, the average value of the lateral runout of the cutting grindstone portion 23 is as large as about 67.5 μm. This means that the width of the kerf of the workpiece 12 is increased more than twice considering that the blade thickness t of the cutting grindstone 23 is about 60 μm. Therefore, it is difficult to form a cutting groove having a small cut width with respect to the workpiece 12.

  On the other hand, in the cutting blade 22 in which the slits 23a shown in FIG. 8B are formed, the average value of the lateral runout of the cutting grindstone portion 23 is about 2.35 μm, and it is within a range of 3 μm or less, which is not problematic as a cutting quality. It is settled. Thus, by forming the slit 23a in the cutting grindstone portion 23, it is possible to prevent the bending of the cutting grindstone portion 23 from being transmitted in the circumferential direction, and it is possible to prevent the occurrence of large lateral deflection.

  The cutting apparatus 10 according to the first embodiment has been described above. In the cutting apparatus 10 according to the present embodiment, since a plurality of slits 23 a are formed in the cutting wheel portion 23 of the cutting blade 22, it is possible to prevent a large lateral vibration from occurring in the cutting wheel portion 23. High processing can be performed. Further, even when the length h of the cutting edge of the cutting grindstone portion 23 exceeds about 20 times the blade thickness t, a large lateral vibration is generated in the cutting grindstone portion 23 by forming the plurality of slits 23a. Therefore, it is possible to form a cutting groove having a small cutting width and a deep cutting depth with respect to the workpiece 12.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, a plurality of slits 23a are formed on the outer peripheral portion of the cutting wheel portion 23 of the cutting blade 22 of the above embodiment, but the present invention is not limited to such an example. For example, when the cutting blade 22 satisfies the relationship of h / t ≦ 20 between the radial length h of the cutting grindstone portion 23 protruding from the outer periphery of the base portion 21 and the blade thickness t, FIG. From the graph shown in FIG. 5, it can be seen that the lateral runout of the cutting grindstone portion 23 is 3 μm or less, and no significant lateral runout occurs. Therefore, by configuring the cutting blade 22 so as to satisfy the relationship of h / t ≦ 20, even if the slit 23a is not provided on the outer peripheral portion of the cutting grindstone 23, no significant lateral vibration of the cutting grindstone 23 occurs. The horizontal wobbling of the cutting grindstone portion 23 can be prevented without requiring processing work and time for providing the slits 23a on the outer peripheral portion of the cutting grindstone portion 23.

  The present invention can be applied to an ultrasonic vibration cutting device, and in particular, can be applied to a cutting blade of an ultrasonic vibration cutting device.

It is a schematic perspective view which shows the cutting device concerning the 1st Embodiment of this invention. It is a perspective view which shows the cutting unit concerning the embodiment. It is a longitudinal cross-sectional view which shows the internal structure of the spindle housing in the cutting unit concerning the embodiment. It is explanatory drawing which shows the principle which ultrasonically vibrates the cutting blade concerning the embodiment to radial direction. It is a partial side view of the cutting unit for demonstrating the measurement of the lateral vibration of a cutting blade. It is a graph which shows the relationship between the length of the blade edge | tip of a cutting whetstone part, and the magnitude | size of the horizontal runout of a cutting whetstone part. Fig.7 (a) is a front view which shows the cutting blade concerning this embodiment, and FIG.7 (b) is a side view which shows the cutting blade concerning this embodiment. FIGS. 8A and 8B are front views for showing measurement points of the lateral vibration of the cutting blade in a comparative experiment. FIG. 8A is a normal cutting blade in which no slit is formed, and FIG. It is the cutting blade concerning this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cutting apparatus 13 Dicing tape 15 Chuck table 20 Cutting unit 21 Base part 22 Cutting blade 23 Cutting grindstone part 23a Slit 24 Tip part 25 Spindle 26 Spindle housing 29 Bolt 33 PZT vibrator

Claims (2)

A spindle, a spindle housing that rotatably supports the spindle, a cutting grindstone portion, and a base portion that supports the cutting grindstone portion, and a cutting blade fixed to the tip of the spindle; And a vibrator that is ultrasonically vibrated,
An ultrasonic wave that transforms the vibration direction of ultrasonic vibration transmitted from the vibrator in the axial direction of the spindle to the radial direction of the cutting blade and cuts the workpiece by the cutting blade that vibrates ultrasonically in the radial direction. In vibration cutting equipment:
An ultrasonic vibration cutting device, wherein a plurality of slits are formed in an outer peripheral portion of the cutting wheel portion of the cutting blade. The cutting blade satisfies h / t> 20, where h is the length in the radial direction of the cutting wheel portion protruding from the outer periphery of the base portion, and t is the thickness of the cutting wheel portion. The ultrasonic vibration cutting device according to claim 1.

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