JP4754874B2 - Ultrasonic vibration cutting equipment - Google Patents

Description

  The present invention relates to an ultrasonic vibration cutting device, and more particularly to an ultrasonic vibration cutting device that cuts a workpiece by ultrasonically vibrating a cutting blade in a radial direction.

  In order to divide a workpiece such as a semiconductor wafer into chips, a cutting apparatus such as a dicing apparatus that cuts a semiconductor wafer into a lattice with a cutting blade that is a cutting grindstone is known. In such a cutting 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 means for solving such a problem, cutting using ultrasonic vibration has been studied. In addition, an ultrasonic wave is a sound range (about 20 kHz or more) above a human audible frequency.

  As an example of a cutting method using such ultrasonic vibration, Japanese Patent Application Laid-Open No. H10-228707 describes cutting by causing a cutting blade to vibrate ultrasonically. In this method, the cutting blade is ultrasonically vibrated so as to bend in the thickness direction (rotation axis direction), and a force that widens the cutting groove of the semiconductor wafer by the ultrasonically vibrating cutting blade works. There was a problem that cutting resistance increased and chipping was likely to occur.

  As a method for solving such a problem, for example, Patent Document 2 describes a method of cutting a workpiece by ultrasonically vibrating a cutting blade in its radial direction. In this method, ultrasonic vibration is transmitted in the direction of the rotation axis of the spindle to which the cutting blade is attached, and the vibration direction is changed by the vibration transmission direction changing portion attached together with the cutting blade, so that the cutting blade is vibrated in the radial direction. ing.

  In this way, by cutting the workpiece with a cutting blade that is ultrasonically vibrated in the radial direction, (1) cutting resistance is reduced compared to normal cutting with a cutting blade that is not ultrasonically vibrated. Therefore, chipping can be suppressed. (2) Since cutting water is easily supplied to the machining point, the temperature rise at the machining point is suppressed and distortion due to heat hardly occurs. (3) Contamination adhered to the cutting blade by vibration. Since the nation is shaken off, there is an advantage that no contamination adheres to the cutting blade, and (4) the burden on the cutting blade is reduced and the life is extended.

JP 2002-336775 A JP 2000-210928 A

  In the ultrasonic vibration cutting apparatus as described above, in order to vibrate the cutting blade in the radial direction by the vibration transmission direction changing portion attached together with the cutting blade, the shape and size of the cutting blade, the length and diameter of the spindle, or Not only the output of the ultrasonic transducer, but also the position where the cutting blade and ultrasonic transducer are attached to the spindle must be designed accurately.

  Usually, in the above ultrasonic vibration cutting apparatus, the minimum vibration amplitude point of the vibration waveform transmitted from the ultrasonic vibrator is set as the vibration transmission direction conversion point, and at the same position as or near the vibration transmission direction conversion point, A cutting blade is arranged. At this vibration transmission direction conversion point, the transmission direction of ultrasonic vibration is changed from the axial direction of the spindle (hereinafter sometimes simply referred to as “axial direction”) to the radial direction of the cutting blade (hereinafter simply referred to as “radial direction”). In some cases.) The blade diameter of the cutting blade, the frequency of the ultrasonic vibration, etc. are adjusted so that the maximum vibration amplitude point in the vibration waveform of the ultrasonic vibration whose transmission direction is converted into the radial direction is located at the cutting edge position of the cutting blade. Has been.

  Therefore, there is a possibility that the ultrasonic vibration in the radial direction of the cutting blade cannot obtain a sufficient amplitude even if the vibration transmission direction conversion point or the maximum vibration amplitude point is slightly deviated from the planned position. May not vibrate.

  For this reason, in order to suitably transmit and convert the ultrasonic vibration waveform, it is preferable that the spindle and the cutting blade are integrally formed as much as possible. However, because the cutting blade is a consumable part, if it is configured integrally with the spindle, the spindle will be replaced, which is not practical. Therefore, a cutting blade (hub blade) in which the grinding wheel portion and the base portion are integrally formed is used so that the spindle and the cutting blade can be configured as integrally as possible, and one side of the base portion of the cutting blade is used. Is provided with a joint having the same diameter as the spindle and joined to the tip of the spindle. Then, the cutting blade can be integrally formed with the spindle by joining from the other side of the base portion of the cutting blade with a bolt via a spacer having the same diameter as the spindle.

  This spacer is used to adjust the ultrasonic vibration wave transmitted from the spindle so that it becomes the maximum vibration amplitude point at the tip in the spindle direction. The spacer may be formed integrally with the cutting blade, but it is not only difficult to handle the cutting blade, but the cutting blade is a consumable member as described above, and it can be separated because it increases the cost. A configuration is preferred.

  In order to transmit ultrasonic vibration efficiently, the cutting blade must have a symmetrical structure at least with respect to the spindle axis direction in which the ultrasonic vibration vibrates and the radial direction of the cutting blade to which the ultrasonic vibration is converted. Is desirable. Therefore, the base part of the cutting blade has a cylindrical shape, and a grinding wheel part is formed on the base part by electrodeposition to constitute the cutting blade.

  However, such cutting blades and spacers do not have any size or shape, and unless they are determined within a certain range or rule, they cannot be vibrated efficiently. There was a problem. In particular, when cutting difficult-to-work materials such as glass and QFN substrates, it is important to obtain sufficient amplitude by efficient ultrasonic vibration.

  Therefore, the present invention has been made in view of such problems, and the object thereof is to optimize the size and shape of the cutting blade and spacer to efficiently ultrasonically vibrate, so that even difficult-to-work materials are problematic. It is an object of the present invention to provide a new and improved ultrasonic vibration cutting apparatus capable of cutting without any problems.

  In order to solve the above-described problems, according to one aspect of the present invention, a spindle, a spindle housing that rotatably supports the spindle, a cutting blade that is attached to the tip of the spindle, and a spindle provided on the spindle that exceeds the spindle. Ultrasonic vibration cutting, which includes a vibrator for ultrasonic vibration, converts the vibration direction of ultrasonic vibration transmitted from the vibrator through the spindle, and cuts the workpiece by ultrasonically vibrating the cutting blade in the radial direction An apparatus is provided.

  In the ultrasonic vibration cutting apparatus, the cutting blade has a pair of substantially cylindrical joints having substantially the same diameter as the tip of the spindle, and a larger diameter than the joints disposed between the pair of joints. It has a substantially cylindrical base part and a grindstone part attached to the base part, and is configured to be symmetric with respect to the axial direction of the spindle and the radial direction of the cutting blade. One of the joints is joined to the tip of the spindle, and the other joint is joined to a substantially cylindrical spacer having the same diameter as the tip of the spindle. Attached to the tip.

Further, the cutting blade and the spacer have the base part diameter d ₁ , the joint part diameter d ₂ , the entire cutting blade thickness L ₁ , the spacer thickness L ₂ , and the base part thickness L _{3. When} the wavelength of the ultrasonic wave transmitted to the base portion is λ, the following expressions (1), (2), (3) and (4) are satisfied.

_{L 1/2 + L 2 =} λ / 4 ··· (1)
2.0 ≦ L ₁ / L ₃ ≦ 6.0 (2)
2.5 ≦ d ₁ / L ₁ ≦ 8.5 (3)
0.3 ≦ d ₂ / d ₁ ≦ 0.5 (4)

Here, the total thickness L ₁ of the cutting blade is the sum of the thickness L ₃ of the base portion and the thickness of a pair of joint portions disposed on both sides of the base portion so as to sandwich the base portion (on the spindle side) It means the thickness of the joining portion + the thickness of the base portion + the thickness of the joining portion on the spacer side).

  In the ultrasonic vibration cutting apparatus, the wavelength λ of the ultrasonic wave is adjusted to be 50 mm to 312.55 mm. The reason why λ is 50 mm to 312.55 mm is that the propagation speed of ultrasonic waves transmitted to the cutting blade is about 5000 m / s, and the practical range of the resonance frequency when machining the workpiece is 16 to This is because it becomes 100 kHz.

  In the ultrasonic vibration cutting apparatus, the maximum vibration amplitude point of ultrasonic vibration transmitted to the cutting blade by the vibrator is the tip of the spacer, and the minimum vibration amplitude point is at or near the mounting position of the grinding wheel portion of the cutting blade. It is comprised so that.

  With this configuration, according to the ultrasonic vibration cutting device according to the present invention, it is possible to efficiently perform ultrasonic vibration by designing the size and shape of the cutting blade and the spacer as described above. Therefore, the ultrasonic vibration cutting device according to the present invention can obtain a sufficiently large radial amplitude (for example, an amplitude of 5 μm or more) of the cutting blade, so that even difficult-to-work materials can be cut without problems. It becomes possible.

  According to the present invention, by designing the size and shape of the cutting blade and spacer as described above, it is possible to efficiently vibrate ultrasonically and obtain a sufficiently large radial amplitude of the cutting blade. Therefore, it is possible to provide an ultrasonic vibration cutting device capable of cutting even difficult-to-work materials without any problem.

  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.

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

  As shown in FIG. 1, the dicing 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 a holding means for holding the workpiece 12, and a cutting unit movement. A mechanism (not shown) and a chuck table moving mechanism (not shown) are provided.

  The cutting unit 20 includes a grindstone portion 22 attached to a spindle. The cutting unit 20 cuts the workpiece 12 to form an extremely thin kerf (cut groove) by cutting the workpiece 12 while rotating the grindstone 22 that ultrasonically vibrates in the radial direction at a high speed. can do.

  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 wafer tape 13 is placed on the chuck table 15, and the workpiece 12 can be stably held by vacuum suction.

  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 grindstone part 22 with respect to the workpiece 12 can be adjusted.

  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 it to the workpiece 12 so that the grindstone 22 The cutting edge is operated with a linear trajectory.

  The dicing apparatus 10 having such a configuration can perform the dicing process on the workpiece 12 by moving the cutting unit 20 and the chuck table 15 relative to each other while cutting the cutting blade rotating at a high speed into the workpiece 12. .

(Configuration of the cutting unit 20)
Next, based on FIG. 2, the structure of the cutting unit 20 which concerns on this embodiment is demonstrated. FIG. 2 is a perspective view showing the cutting unit 20 according to this embodiment.

  As shown in FIG. 2, the cutting unit 20 includes, for example, a grindstone portion 22 of a cutting blade, a blade base 21 integrated with the grindstone portion 22, and a fixing member that fixes the blade base 21 to the tip of a spindle 25. The spacer 23, the spindle 25, the spindle housing 26, the cutting water supply nozzle 27, and the wheel cover 28 are mainly provided as an example.

  The grindstone portion 22 is, for example, an extremely thin cutting grindstone having a substantially ring shape, and is formed by electroforming abrasive grains such as diamond. The grindstone 22 is integrally formed with a blade base 21 that supports the grindstone 22. That is, the grindstone 22 and the blade base 21 constitute a cutting blade (so-called hub blade) in which the grindstone and the mount are integrated. The grindstone 22 and the blade base 21 (hereinafter sometimes simply referred to as “cutting blade”) are mounted on the tip of the spindle 25 by a spacer 23 and a fixing bolt (not shown). That is, as shown in FIG. 2, the spacer 23 is formed with a through hole 23a through which a fixing bolt passes, and this fixing bolt penetrates the spacer 23 and the blade base 21 in the Y-axis direction to reach the spindle 25. Is fastened to a female screw portion formed at the tip of the head (see FIG. 3). Thus, the blade base 21 can be locked with the spacer 23 and the fixing bolt, and can be fixed to the tip portion of the spindle 25.

  The blade base 21 includes a base portion 211 to which the grindstone portion 22 is attached, and a pair of joint portions 212 and 213 disposed on both sides of the base portion 21 so as to sandwich the base portion 211. Details will be described later.

  The spindle 25 is, for example, a rotating shaft for transmitting a rotational driving force of a motor (not shown) described later to the cutting blade, and rotates the mounted cutting blade 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 the grindstone 22 and the blade base 21 are 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 rotatable at high speed by an air bearing provided therein.

  Here, based on FIG. 3, the internal structure of the spindle housing 26 according to the present embodiment will be described. 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, an exhaust path (not shown) for discharging the air ejected by the radial air bearing 30 and the thrust air bearing 31, and a rotor A motor 32 having a 321 and a stator 322, a stator power supply 34 for supplying power to the stator 322, a PZT vibrator 33 as an ultrasonic vibrator provided on the rear end side of the spindle 25, and PZT Non-contact power feeding device 40 for supplying power to the vibrator 33 , It is provided.

  The PZT vibrator 33 to which power is supplied from the non-contact power feeding device 40 generates ultrasonic vibrations and causes the spindle 25 to vibrate ultrasonically. This ultrasonic vibration is transmitted in the axial direction of the spindle 25 (Y-axis direction) and travels toward the cutting blade mounted on the tip of the spindle 25.

  Further, the Y-axis position of the vibration transmission direction conversion point when the ultrasonic vibration transmitted in the axial direction of the spindle 25 (Y-axis direction) is converted into the radial direction of the cutting blade (XZ plane direction) is The structure and arrangement of the spindle 25 and the frequency of the PZT vibrator 33 are adjusted so as to be the same as or close to the mounting position of the grinding wheel portion 22 of the cutting blade with respect to 25 (Y-axis position of the grinding wheel portion 22). .

  The description of the configuration of the cutting unit 20 will be continued based on FIG. The cutting water supply nozzle 27 is detachably provided on both sides of the cutting blade, for example, and supplies cutting water to the side surface of the cutting blade and the vicinity of the processing point to cool it. The wheel cover 28 is provided so as to cover the outer periphery of the cutting blade, and protects the cutting blade and prevents scattering of cutting water and cutting waste.

  The cutting unit 20 having such a configuration rotates the cutting blade at a high speed by the spindle 25 and cuts the cutting edge of the cutting blade into the workpiece 12 so as to relatively move the cutting blade. 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.

  With the configuration described above, ultrasonic vibration is transmitted in the axial direction of the spindle 25, and the transmission direction of the transmitted ultrasonic vibration is determined at the vibration transmission direction conversion point at substantially the same position as the grinding wheel portion 22 of the cutting blade. It can be converted into the radial direction of the cutting blade. Accordingly, the workpiece 12 is vibrated ultrasonically in the radial direction, that is, while the grinding wheel portion 22 of the ring-shaped cutting blade is vibrated so as to repeatedly expand and contract at a high frequency, the grinding stone portion 22 causes the workpiece 12 to vibrate. Can be cut.

(Principle of ultrasonic vibration of cutting blade in radial direction)
The principle of ultrasonically oscillating the cutting blade in the radial direction as described above is described in, for example, 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 of the mechanical spindle mechanism. There is no need.

  The minimum vibration amplitude point B of the vibration waveform W1 is a vibration transmission direction conversion point, and the grindstone 22 of the cutting blade is disposed at the same position as or near the vibration transmission direction conversion point. At the vibration transmission direction conversion point B, the transmission direction of the ultrasonic vibration is converted from the axial direction of the spindle 25 to the radial direction of the cutting blade. Thus, the blade diameter of the cutting blade 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 located at the cutting edge position of the cutting blade. The frequency etc. are adjusted.

  Further, in order to suitably transmit and convert the ultrasonic vibration, the grindstone 22 and the blade base 21 are integrally formed, and the spacer 23, the blade base 21 and the tip of the spindle 25 are in close contact with each other. And is configured to be firmly fixed. Further, the blade base 21 is shaped so as to be symmetrical in the Y-axis direction with the vibration transmission direction conversion point B as the center.

  As described above, by changing the transmission direction of the ultrasonic vibration transmitted through the spindle 25 in the axial direction, the cutting blade repeatedly expands and contracts, and the cutting edge of the cutting blade moves in the radial direction. Vibrate.

(Configuration of cutting blade and spacer 23)
Next, the configuration of the cutting blade and the spacer 23 for efficiently transmitting ultrasonic vibration will be described with reference to FIGS. 2, 3, 5 and 6. FIG. 5 is an enlarged cross-sectional view showing the base 211, the joints 212 and 213, and the spacer 23 according to this embodiment. FIG. 6 shows the experimental results using the cutting unit 20 according to the present embodiment. (A) shows the relationship between the blade radial amplitude [μm] and L ₁ / L _3, and (b) shows The relationship between the amplitude [μm] in the blade radial direction and d ₁ / L ₁ , (c) is a graph showing the relationship between the amplitude [μm] in the blade radial direction and d ₂ / d ₁ .

  In the dicing apparatus 10 as the ultrasonic vibration cutting apparatus as described above, it is preferable that the spindle 25 and the cutting blade are integrally formed as much as possible in order to suitably transmit and convert the ultrasonic vibration waveform. In order to efficiently transmit ultrasonic vibrations, the cutting blade has a symmetrical structure at least in the axial direction of the spindle 25 where the ultrasonic waves vibrate and in the radial direction of the cutting blades where the vibration direction of the ultrasonic vibrations is converted. It is preferable.

  Therefore, in the cutting unit 20 according to the present embodiment, as shown in FIGS. 2 and 3, the cutting blade is configured as follows. That is, first, the base portion 211 of the cutting blade is formed into a substantially cylindrical shape having a diameter larger than that of the spindle 25, and a substantially ring-shaped grindstone portion 22 is formed on the base portion 211 by electrodeposition. Further, a pair of substantially cylindrical joints having substantially the same diameter as the tip portion 24 of the spindle 25 so as to sandwich the base portion 211 on both sides (the spindle 25 side and the spacer 23 side) of the base portion 211. Portions 212 and 213 are provided. Then, using the fixing bolt 29, one (spindle 25 side) joining portion 212 and the tip end 24 of the spindle 25 are joined, and the other (spacer 23 side) joining portion 213 and spacer 23 (the spacer 23 is a spindle). The cutting blade can be configured integrally with the spindle by joining the front end portion 24 of 25 and the tip end portion 24 to each other.

  In the cutting unit 20 according to the present embodiment, as described above, the maximum vibration amplitude point A of the ultrasonic vibration transmitted to the cutting blade by the PZT vibrator 33 is the tip of the spacer 23, and the minimum vibration amplitude point is obtained. B is configured to be at or near the mounting position of the grindstone 22 of the cutting blade (see FIG. 4).

When such a cutting blade and spacer are used, the ultrasonic vibration is not efficiently performed in any shape and size, and a sufficiently large amplitude cannot be obtained unless the following settings are made. Here, the "sufficiently large amplitude" also in hard materials such as glass or QFN substrate that not mean that the degree of amplitude can be cut without any problem.

In order to perform such efficient ultrasonic vibration, in the dicing apparatus 10 as described above, the diameter of the base portion 211 is d ₁ and the diameters of the joint portions 212 and 213 are d as shown in FIG. ₂ , where L ₁ is the thickness of the entire cutting blade, L _{2 is} the thickness of the spacer 23, L _{3 is} the thickness of the base 211, and λ is the wavelength of the ultrasonic wave transmitted to the base 211. It is necessary to satisfy the relationships (1), (2), (3) and (4).

_{L 1/2 + L 2 =} λ / 4 ··· (1)
2.0 ≦ L ₁ / L ₃ ≦ 6.0 (2)
2.5 ≦ d ₁ / L ₁ ≦ 8.5 (3)
0.3 ≦ d ₂ / d ₁ ≦ 0.5 (4)

Here, the thickness L _{1 of the} entire cutting blade is the thickness of the pair of joint portions 212 and 213 arranged on both sides of the base portion 211 so as to sandwich the base portion 211 with the thickness L ₃ of the base portion 211. , That is, the sum of the thickness of the joint portion 212 on the spindle 25 side + the thickness of the base portion 211 + the thickness of the joint portion 213 on the spacer 23 side.

  In the ultrasonic vibration cutting apparatus, the wavelength λ of the ultrasonic wave is adjusted to be 50 mm to 312.55 mm. The reason why λ is 50 mm to 312.55 mm is that the propagation speed of ultrasonic waves transmitted to the cutting blade is about 5000 m / s, and the practical range of the resonance frequency when machining the workpiece is 16 to This is because it becomes 100 kHz.

  Here, normally, the blade base 21 of the cutting blade (the base portion 211 and the joint portions 212 and 213) is made of aluminum, while the spindle 25 is made of stainless steel and is made of different metals. Since the speed at which ultrasonic waves are transmitted hardly changes in metal (for example, aluminum is about 5163 m / s and stainless steel is about 5130 m / s), it is considered that there is no problem even if λ is adjusted as described above. Note that the speed at which the ultrasonic waves are transmitted also varies depending on the metal processing method (for example, due to the difference in the processing method, the range of 4900 to 5200 m / s for aluminum and 5000 to 5200 m / s for stainless steel).

  Hereinafter, the above formulas (1) to (4) will be described in detail. First, the equation (1) will be described with reference to FIG.

As described above, the vibration in the radial direction of the cutting blade has a sufficiently large amplitude, and in order to efficiently perform ultrasonic vibration, the ultrasonic vibration (W1) transmitted from the PZT vibrator 33 via the spindle 25 is effective. Is adjusted so that the maximum vibration amplitude point A becomes the tip of the spacer 23 and the minimum vibration amplitude point B becomes the mounting position of the cutting blade, and the vibration direction of the ultrasonic vibration is converted at the minimum vibration amplitude point B. There is a need to. Therefore, in this embodiment, as shown in FIG. 5, the ultrasonic vibration wave W1 transmitted from the PZT vibrator 33 via the spindle 25 has a maximum amplitude at the position A which is the tip of the spacer 23. Thus, the wavelength λ is adjusted so that the amplitude is minimized at the position B, which is the midpoint of the entire cutting blade in the thickness direction (the midpoint of the base portion 211 in the thickness direction). That is, first length of the quarter of the wavelength of the wave W1 is, be equal to the sum of the thickness L ₂ of the spacer and one-half of the thickness L ₁ of the entire cutting blade, efficient order to ultrasonic vibration This is one of the necessary conditions.

  Next, the critical significance of the above formulas (2) to (4) will be described with reference to FIG. About Formula (2)-(4), the critical value was defined by the experiment shown below.

In this embodiment, when the radial amplitude of the cutting blade is 5 μm or more, it is determined that efficient ultrasonic vibration is being performed.

In the present embodiment, λ (wavelength of ultrasonic wave propagated to the cutting blade) = 92 mm, L ₁ (total thickness of the cutting blade) = 12 mm, L ₂ (thickness of the spacer 23) = 17 mm, d ₂ ( Experiments were performed with the diameters of the joint portions 212 and 213) = 30 mm and L ₃ (thickness of the base portion 211) = 4 mm. That is, for L ₁ / L ₃ , the radial amplitude of the cutting blade was measured when L ₁ was fixed and L ₃ was changed. For d ₁ / L ₁ , the radial amplitude of the cutting blade was measured when d ₁ was changed with L ₁ fixed. As for d 2 _/ d _1, to measure the amplitude of the radial cutting blade when securing the d ₂ is changed to d _1.

  In addition, as the grinding wheel portion 22 of the cutting blade, one having a size of 3 inches was used, and the experiment was performed with the cutting blade stopped.

As a result, as shown in FIG. 6, L ₁ / L ₃ is in the range of 2.0 to 6.0, and d ₁ / L ₁ is in the range of 2.5 to 8.5. , D ₂ / d ₁ , the amplitude in the radial direction of the cutting blade was 5 μm or more in the range of 0.3 to 0.5. From this, it was found that it is necessary to satisfy the expressions (2), (3) and (4) as conditions necessary for efficient ultrasonic vibration.

  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 this example. 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, in the above embodiment, the dicing apparatus 10 is described as an example of the ultrasonic vibration cutting apparatus, but the present invention is not limited to such an example. For example, as long as it is a device that cuts the workpiece 12 using the grindstone portion 22 that rotates at high speed by the spindle 25, for example, various cutting devices that perform cutting processing other than dicing processing may be used.

  In the cutting unit 20 according to the above embodiment, the example of the air spindle has been described as the support mechanism of the spindle 25, but the present invention is not limited to this example. For example, the support mechanism of the spindle 25 may be a mechanical spindle that mechanically supports the spindle 25 with a bearing. The present invention is applicable to any spindle support mechanism as long as it is an ultrasonic vibration cutting device that ultrasonically vibrates the grindstone 22 in the radial direction.

  In the above embodiment, the PZT vibrator 33 is disposed on the rear side of the spindle 25. However, the present invention is not limited to this example. For example, the PZT vibrator 33 may be disposed at the center or tip side of the spindle 25.

  The present invention is applicable to an ultrasonic vibration cutting apparatus that performs cutting while ultrasonically vibrating a cutting blade in the radial direction.

1 is an overall perspective view showing a dicing apparatus according to a first embodiment of the present invention. It is a perspective view which shows the cutting unit which concerns on the same embodiment. It is a longitudinal cross-sectional view which shows the internal structure of the spindle housing in the cutting unit which concerns on the same embodiment. It is explanatory drawing which shows the principle which ultrasonically vibrates the cutting blade which concerns on the embodiment to radial direction. It is an expanded sectional view which shows the base part, junction part, and spacer which concern on the embodiment. Are experimental results using a cutting unit according to the embodiment, the amplitude of the base radially [[mu] _m], a graph showing the relationship between the _{L 1 / L 3, d 1} / L 1 and _d 2 / _{d 1} is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Dicing apparatus 12 Workpiece 20 Cutting unit 21 Blade support part 22 Cutting blade 23 Spacer 25 Spindle 26 Spindle housing 33 PZT vibrator 211 Base part 212,213 Joint part

Claims (1)

A spindle, a spindle housing that rotatably supports the spindle, a cutting blade attached to a tip of the spindle, and a vibrator that is provided on the spindle and vibrates the spindle ultrasonically. In an ultrasonic vibration cutting apparatus for converting a vibration direction of ultrasonic vibration transmitted through the spindle and cutting the workpiece by ultrasonically vibrating the cutting blade in a radial direction:
The cutting blade is
A pair of substantially cylindrical joints having substantially the same diameter as the tip of the spindle, a substantially cylindrical base having a larger diameter than the joints disposed between the pair of joints, And a grindstone attached to the base,
It is configured to be symmetric with respect to the axial direction of the spindle and the radial direction of the cutting blade,
One of the pair of joints is joined to the tip of the spindle, and the other joint is a substantially columnar spacer having substantially the same diameter as the tip of the spindle. And is attached to the tip of the spindle by sandwiching it with the spacer,
In the cutting blade and the spacer, the diameter of the base portion is d ₁ , the diameter of the joint portion is d ₂ , the entire thickness of the cutting blade is L ₁ , the thickness of the spacer is L ₂ , When the thickness is L ₃ and the wavelength of the ultrasonic wave transmitted to the base portion is λ, the following expressions (1), (2), (3), and (4) are satisfied. , Ultrasonic vibration cutting equipment.
_{L 1/2 + L 2 =} λ / 4 ··· (1)
2.0 ≦ L ₁ / L ₃ ≦ 6.0 (2)
2.5 ≦ d ₁ / L ₁ ≦ 8.5 (3)
0.3 ≦ d ₂ / d ₁ ≦ 0.5 (4)

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