JP2015170744A - Cutting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting device which can appropriately detect abnormality during cutting.SOLUTION: A cutting device comprises: an oscillation signal generation means (68) for generating an oscillation signal corresponding to oscillation of a cutting blade (60); and control means (78) for determining a state of the cutting blade based on the oscillation signal generated by the oscillation signal generation means. The oscillation signal generation means is arranged in a first flange member (46) and includes an ultrasonic transducer (70) for generating a voltage equivalent to the oscillation signal corresponding to the oscillation of the cutting blade; and transmission means (72) connected with the ultrasonic transducer, for transmitting voltage to the control means. A plurality of ultrasonic transducers (70a, 70b, 70c) which have different resonance frequencies from each other and are arranged in parallel with first coil means (74) that composes the transmission means are arranged on the first flange member.

Description

  The present invention relates to a cutting device for cutting a plate-like workpiece.

  A plate-like workpiece typified by a semiconductor wafer is cut by, for example, a cutting device having an annular cutting blade and divided into a plurality of chips. If an abnormality such as chipping of the cutting blade, a decrease in cutting performance, contact with foreign matter, or a change in processing load occurs during the cutting of the workpiece, the cutting blade vibrates.

  Therefore, various methods have been studied in order to detect such an abnormality. For example, chipping of the cutting blade can be detected by a method using an optical sensor (see, for example, Patent Document 1). It is also possible to detect a change in machining load by monitoring the current of the spindle (motor) on which the cutting blade is mounted.

Japanese Patent No. 4704816

  However, the above-described method using the optical sensor has a problem that abnormalities other than cutting blade chipping cannot be detected appropriately. On the other hand, the current monitoring method can detect various abnormalities that affect the rotation of the cutting blade, but it is not suitable for detecting slight abnormalities because of some measurement error.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a cutting apparatus capable of appropriately detecting an abnormality during cutting.

  According to the present invention, it includes a chuck table for holding a workpiece and a cutting means having a cutting blade for cutting the workpiece held on the chuck table, the cutting means rotating on a spindle housing. Corresponding to vibrations of a cutting blade in a cutting apparatus comprising a spindle that is supported and a first flange member and a second flange member that are attached to an end of the spindle and sandwich the cutting blade Vibration signal generating means for generating the generated vibration signal, and control means for determining the state of the cutting blade based on the vibration signal generated by the vibration signal generating means. An ultrasonic vibrator that is disposed on the flange member and generates a voltage corresponding to the vibration signal corresponding to the vibration of the cutting blade, and is connected to the ultrasonic vibrator, Transmission means for transmitting pressure to the control means, the transmission means being opposed to the first coil means mounted on the first flange member and the first coil means with a gap. A plurality of ultrasonic transducers having different resonance frequencies connected in parallel to the first coil means, the second coil means disposed in the spindle housing. A cutting apparatus is provided in which is provided.

  In the present invention, it is preferable that the control means performs Fourier transform analysis on a waveform corresponding to a time change of the vibration signal, and determines a change in the state of the cutting blade from a change in the vibration component.

  The cutting apparatus of the present invention includes vibration signal generating means for generating a vibration signal corresponding to the vibration of the cutting blade, and control means for determining the state of the cutting blade based on the vibration signal generated by the vibration signal generating means. Therefore, it is possible to appropriately detect abnormalities during cutting accompanied by vibration of the cutting blade.

It is a perspective view showing typically an example of composition of a cutting device concerning this embodiment. It is a disassembled perspective view which shows the structure of a cutting unit typically. It is a figure which shows typically the cross section etc. of a cutting unit. FIG. 4A is a diagram schematically illustrating the arrangement of the ultrasonic transducer and the first inductor, and FIG. 4B is a circuit diagram illustrating the connection relationship between the ultrasonic transducer and the first inductor. It is. FIG. 5A is a graph showing an example of a waveform (voltage in the time domain) of a voltage transmitted to the control device, and FIG. 5B is an example of a waveform after Fourier transform (a waveform in the frequency domain). It is a graph which shows. It is a graph which shows the example of the waveform (waveform of a frequency domain) before and behind the occurrence of abnormality.

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing a configuration example of a cutting apparatus according to the present embodiment. As shown in FIG. 1, the cutting device 2 includes a base 4 that supports each component.

  On the upper surface of the base 4, a rectangular opening 4 a that is long in the X-axis direction (front-rear direction, processing feed direction) is formed. In the opening 4a, an X-axis moving table 6, an X-axis moving mechanism (not shown) for moving the X-axis moving table 6 in the X-axis direction, and a waterproof cover 8 that covers the X-axis moving mechanism are provided.

  The X-axis movement mechanism includes a pair of X-axis guide rails (not shown) parallel to the X-axis direction, and an X-axis movement table 6 is slidably installed on the X-axis guide rails. A nut portion (not shown) is fixed to the lower surface side of the X-axis moving table 6, and an X-axis ball screw (not shown) parallel to the X-axis guide rail is screwed to the nut portion.

  An X-axis pulse motor (not shown) is connected to one end of the X-axis ball screw. By rotating the X-axis ball screw with the X-axis pulse motor, the X-axis moving table 6 moves in the X-axis direction along the X-axis guide rail.

  On the X-axis moving table 6, a chuck table 10 for sucking and holding a plate-like workpiece (not shown) is provided. The workpiece is, for example, a disk-shaped semiconductor wafer, a resin substrate, a ceramic substrate, or the like, and the lower surface side is sucked and held by the chuck table 10.

  The chuck table 10 is connected to a rotation mechanism (not shown) such as a motor, and rotates around a rotation axis extending in the Z-axis direction (vertical direction). Further, the chuck table 10 is moved in the X-axis direction by the above-described X-axis moving mechanism. Around the chuck table 10 is provided a clamp 12 for holding and fixing an annular frame (not shown) that supports the workpiece.

  The surface (upper surface) of the chuck table 10 is a holding surface 10a for sucking and holding a workpiece. The holding surface 10 a is connected to a suction source (not shown) through a flow path (not shown) formed inside the chuck table 10.

  On the upper surface of the base 4, a gate-type support structure 16 that supports a cutting unit (cutting means) 14 is disposed so as to straddle the opening 4 a. A cutting unit moving mechanism 18 that moves the cutting unit 14 in the Y-axis direction (index feed direction) and the Z-axis direction is provided on the upper front surface of the support structure 16.

  The cutting unit moving mechanism 18 includes a pair of Y-axis guide rails 20 arranged on the front surface of the support structure 16 and parallel to the Y-axis direction. On the Y-axis guide rail 20, a Y-axis movement table 22 constituting the cutting unit moving mechanism 18 is slidably installed.

  A nut portion (not shown) is fixed to the rear surface side (rear surface side) of the Y-axis moving table 22, and a Y-axis ball screw 24 parallel to the Y-axis guide rail 20 is screwed to the nut portion. Yes. A Y-axis pulse motor (not shown) is connected to one end of the Y-axis ball screw 24. If the Y-axis ball screw 24 is rotated by the Y-axis pulse motor, the Y-axis moving table 22 moves in the Y-axis direction along the Y-axis guide rail 20.

  A pair of Z-axis guide rails 26 parallel to the Z-axis direction are provided on the front surface (front surface) of the Y-axis moving table 22. A Z-axis movement table 28 is slidably installed on the Z-axis guide rail 26.

  A nut portion (not shown) is fixed to the rear surface side (rear surface side) of the Z-axis moving table 28, and a Z-axis ball screw 30 parallel to the Z-axis guide rail 26 is screwed to the nut portion. Yes. A Z-axis pulse motor 32 is connected to one end of the Z-axis ball screw 30. When the Z-axis ball screw 30 is rotated by the Z-axis pulse motor 32, the Z-axis moving table 28 moves in the Z-axis direction along the Z-axis guide rail 26.

  A cutting unit 14 for cutting a workpiece is provided below the Z-axis moving table 28. A camera 34 that captures an image of the upper surface side of the workpiece is installed at a position adjacent to the cutting unit 14. By moving the Y-axis movement table 22 and the Z-axis movement table 28 as described above, the cutting unit 14 and the camera 34 move in the Y-axis direction and the Z-axis direction.

  FIG. 2 is an exploded perspective view schematically showing the structure of the cutting unit 14, and FIG. 3 is a view schematically showing a cross section of the cutting unit 14. 2 and 3, a part of the configuration of the cutting unit 14 is omitted.

  The cutting unit 14 includes a spindle housing 36 fixed to the lower part of the Z-axis moving table 28. The spindle housing 36 includes a substantially rectangular parallelepiped housing body 38 and a cylindrical housing cover 40 fixed to one end of the housing body 38.

  The housing main body 38 accommodates a spindle 42 that rotates around the Y axis. One end side of the spindle 42 protrudes from the housing body 38 to the outside. A motor (not shown) for rotating the spindle 42 is connected to the other end side of the spindle 42.

  A circular opening 40 a is formed at the center of the housing cover 40. Further, a locking portion 40c formed with a screw hole 40b is provided on the housing body 38 side of the housing cover 40. The housing cover 40 can be fixed to the housing body 38 by inserting one end of the spindle 42 into the opening 40a and tightening the screw 44 (FIG. 3) into the screw hole 38a of the housing body 38 through the screw hole 40b of the locking portion 40c. .

  An opening 42a is formed at one end of the spindle 42, and a screw groove is provided on the inner wall surface of the opening 42a. A first flange member 46 is attached to one end of the spindle 42.

  The first flange member 46 includes a flange portion 48 extending outward in the radial direction, and a first boss portion 50 and a second boss portion 52 that respectively protrude from the front and back surfaces of the flange portion 48. In the center of the first flange member 46, an opening 46 a that penetrates the first boss portion 50, the flange portion 48, and the second boss portion 52 is formed.

  One end of the spindle 42 is fitted into the opening 46a of the first flange member 46 from the back surface side (spindle housing 36 side). In this state, if the washer 56 is positioned in the opening 46 a and the fixing bolt 58 is tightened into the opening 42 a through the washer 56, the first flange member 46 is fixed to the spindle 42. The outer peripheral surface 58a of the bolt 58 is provided with a thread corresponding to the thread groove of the opening 42a.

  The outer peripheral surface of the flange portion 48 is a contact surface 48 a that contacts the back surface of the cutting blade 60. The contact surface 48a is formed in an annular shape when viewed from the Y-axis direction (axial center direction of the spindle 42).

  The first boss portion 50 is formed in a cylindrical shape, and a screw thread is provided on the outer peripheral surface 50a on the tip side. In the center of the cutting blade 60, a circular opening 60a is formed. The cutting blade 60 is attached to the first flange member 46 by inserting the first boss portion 50 through the opening 60a.

  The cutting blade 60 is a so-called hub blade, and an annular cutting blade 64 for cutting a workpiece is fixed to the outer periphery of a disc-shaped support base 62. The cutting blade 64 is formed to a predetermined thickness by mixing abrasives such as diamond and CBN (Cubic Boron Nitride) with a bond material (binding material) such as metal or resin. As the cutting blade 60, a washer blade composed only of a cutting blade may be used.

  An annular second flange member 66 is disposed on the surface side of the cutting blade 60 in a state where the cutting blade 60 is mounted on the first flange member 46. A circular opening 66a is formed in the center of the second flange member 66, and a screw corresponding to a thread formed on the outer peripheral surface 50a of the first boss portion 50 is formed on the inner wall surface of the opening 66a. Grooves are provided.

  The back surface on the outer peripheral side of the second flange member 66 is an abutting surface 66 b (FIG. 3) that abuts on the surface of the cutting blade 60. The contact surface 66 b is provided at a position corresponding to the contact surface 48 a of the first flange member 46.

  The cutting blade 60 is sandwiched between the first flange member 46 and the second flange member 66 by tightening the tip of the first boss portion 50 into the opening 66 a of the second flange member 66.

  The cutting unit 14 configured as described above is provided with a vibration detection mechanism for detecting the vibration of the cutting blade 60. The vibration detection mechanism includes a vibration signal generator (vibration signal generator) 68 (FIG. 3) that generates a vibration signal corresponding to the vibration of the cutting blade 60.

The vibration signal generation device 68 includes a plurality of ultrasonic transducers 70 fixed inside the first flange member 46. The ultrasonic vibrator 70 includes, for example, barium titanate (BaTiO ₃ ), lead zirconate titanate (Pb (Zi, Ti) O ₃ ), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), and the like. The vibration of the cutting blade 60 is converted into a voltage (vibration signal).

  Usually, the ultrasonic transducer 70 is configured to resonate with respect to a vibration having a predetermined frequency. Therefore, the frequency of vibration that can be detected by the vibration detection mechanism is determined according to the resonance frequency of the ultrasonic transducer 70. In the present embodiment, a plurality of ultrasonic transducers 70 having different resonance frequencies are used so that vibrations in a wide frequency range can be detected.

  A non-contact type transmission path (transmission means) 72 (FIG. 3) for transmitting a voltage generated by the ultrasonic vibrator 70 is connected to the ultrasonic vibrator 70. The transmission path 72 includes a first inductor (first coil means) 74 connected to the ultrasonic transducer 70 and a second inductor (second coil) facing the first inductor 74 at a predetermined interval. Coil means) 76.

  The first inductor 74 and the second inductor 76 are typically annular coils around which conductive wires are wound, and are fixed to the first flange member 46 and the housing cover 40, respectively.

  4A is a diagram schematically showing the arrangement of the ultrasonic transducer 70 and the first inductor 74, and FIG. 4B is a connection relationship between the ultrasonic transducer 70 and the first inductor 74. As shown in FIG. FIG.

  In the present embodiment, as shown in FIG. 4A, three types of super frequency with different resonance frequencies are arranged at positions overlapping with the first inductor 74 when viewed from the Y-axis direction (direction of the axis O of the spindle 42). Two ultrasonic transducers 70 (a first ultrasonic transducer 70a, a second ultrasonic transducer 70b, and a third ultrasonic transducer 70c) are disposed.

  For example, the frequency ranges of vibrations detected using the first ultrasonic transducer 70a, the second ultrasonic transducer 70b, and the third ultrasonic transducer 70c are 50 kHz to 100 kHz, 100 kHz to 300 kHz, respectively. 300 kHz to 500 kHz. In this way, vibrations in a wide frequency range can be detected by using a plurality of ultrasonic transducers 70 having different resonance frequencies. In the case described above, vibrations in the frequency range of 50 kHz to 500 kHz can be detected appropriately.

  The two first ultrasonic transducers 70 a are arranged symmetrically with respect to the axis O of the spindle 42. Further, the two second ultrasonic transducers 70 b are arranged symmetrically with respect to the axis O of the spindle 42. Similarly, the two third ultrasonic transducers 70 c are arranged symmetrically with respect to the axis O of the spindle 42.

  Thus, by arranging the plurality of ultrasonic transducers 70 symmetrically with respect to the axis O of the spindle 42, the vibration of the cutting blade 60 can be detected with high accuracy. Note that the number, arrangement, shape, and the like of the ultrasonic transducers 70 are not limited to the mode illustrated in FIG.

  As shown in FIG. 4B, the first ultrasonic transducer 70 a, the second ultrasonic transducer 70 b, and the third ultrasonic transducer 70 c are connected in parallel to the first inductor 74. ing. Further, the first inductor 74 and the second inductor 76 face each other and are magnetically coupled. Therefore, the voltage generated in each ultrasonic transducer 70 is transmitted to the second inductor 76 side by mutual induction between the first inductor 74 and the second inductor 76.

  A control device (control means) 78 is connected to the second inductor 76. The control device 78 determines the vibration state of the cutting blade based on the voltage transmitted from the second inductor 76. Specifically, a spectrum corresponding to the time change of the voltage transmitted per unit time (waveform in the time domain) is subjected to spectrum analysis by Fourier transform (for example, fast Fourier transform), and the obtained frequency domain The state of the cutting blade 60 is determined based on the waveform. The unit time is the time required for cutting one line (for each cut line), the time required for cutting one workpiece (for each workpiece), and the time required for cutting an arbitrary distance (cut) Various modes such as every distance) are conceivable.

  FIG. 5A is a graph showing an example of a waveform of a voltage (waveform in the time domain) transmitted to the control device 78, and FIG. 5B shows a waveform after Fourier transform (a waveform in the frequency domain). It is a graph which shows an example. 5A, the vertical axis represents voltage (V) and the horizontal axis represents time (t). In FIG. 5B, the vertical axis represents amplitude and the horizontal axis represents frequency (f). Each is shown.

  Thus, if the waveform of the voltage (vibration signal) from the vibration signal generator 68 is Fourier-transformed by the controller 78, the vibration of the cutting blade 60 is divided into main frequency components as shown in FIG. 5B. Thus, it is possible to easily analyze abnormalities that occur during cutting. Thereby, the abnormality during cutting can be detected accurately in real time.

  FIG. 6 is a graph showing an example of a waveform (frequency domain waveform) before and after the occurrence of an abnormality. In FIG. 6, the vertical axis represents amplitude and the horizontal axis represents frequency (f). In FIG. 6, the waveform before the occurrence of the abnormality is indicated by a solid line, and the waveform after the occurrence of the abnormality is indicated by a broken line.

  As shown in FIG. 6, the waveform after the occurrence of abnormality has a vibration mode (vibration component) on the high frequency side that is not found in the waveform before the occurrence of abnormality. For example, the control device 78 compares the waveforms before and after the occurrence of the abnormality (the waveform in the frequency domain) and determines that an abnormality corresponding to the vibration mode found only in the waveform after the occurrence of the abnormality has occurred.

  As described above, the cutting device 2 according to the present embodiment is generated by the vibration signal generator (vibration signal generator) 68 that generates a vibration signal corresponding to the vibration of the cutting blade 60 and the vibration signal generator 68. Since the control device (control means) 78 that determines the state of the cutting blade 60 based on the vibration signal is provided, it is possible to appropriately detect an abnormality during cutting accompanied by vibration of the cutting blade 60.

  Further, in the cutting device 2 according to the present embodiment, since the waveform (waveform in the time domain) corresponding to the time change of the voltage (vibration signal) is Fourier-transformed, compared with the case of directly analyzing the vibration signal, Analysis of abnormalities that occur during cutting becomes easy. Thereby, the abnormality during cutting can be detected with high accuracy.

  The present invention is not limited to the description of the above embodiment. For example, the voltage (vibration signal) may be analyzed without Fourier transform. In addition, the configurations, methods, and the like according to the above-described embodiments can be changed as appropriate without departing from the scope of the object of the present invention.

2 Cutting device 4 Base 4a Opening 6 X-axis moving table 8 Waterproof cover 10 Chuck table 10a Holding surface 12 Clamp 14 Cutting unit (cutting means)
16 Support structure 18 Cutting unit moving mechanism 20 Y-axis guide rail 22 Y-axis moving table 24 Y-axis ball screw 26 Z-axis guide rail 28 Z-axis moving table 30 Z-axis ball screw 32 Z-axis pulse motor 34 Camera 36 Spindle housing 38 Housing body 38a Screw hole 40 Housing cover 40a Opening 40b Screw hole 40c Locking part 42 Spindle 42a Opening 44 Screw 46 First flange member 46a Opening 48 Flange part 48a Contact surface 50 First boss part 50a Outer peripheral face 52 Second boss part 56 Washer 58 Bolt 58a Outer peripheral surface 60 Cutting blade 60a Opening 62 Support base 64 Cutting blade 66 Second flange member 66a Opening 66b Abutting surface 68 Vibration signal generating device (vibration signal generating means)
70 ultrasonic transducer 70a first ultrasonic transducer 70b second ultrasonic transducer 70c third ultrasonic transducer 72 transmission path (transmission means)
74 First inductor (first coil means)
76 Second inductor (second coil means)
78 Control device (control means)
O axis

Claims (2)

A chuck table for holding a workpiece, and a cutting means including a cutting blade for cutting the workpiece held on the chuck table,
The cutting means includes a spindle rotatably supported by a spindle housing, and a first flange member and a second flange member that are attached to an end portion of the spindle and sandwich the cutting blade. In
Vibration signal generating means for generating a vibration signal corresponding to the vibration of the cutting blade;
Control means for determining the state of the cutting blade based on the vibration signal generated by the vibration signal generating means,
The vibration signal generating means includes
An ultrasonic transducer that is disposed on the first flange member and generates a voltage corresponding to the vibration signal corresponding to the vibration of the cutting blade;
A transmission means connected to the ultrasonic transducer and transmitting the voltage to the control means;
The transmission means includes a first coil means mounted on the first flange member, a second coil means disposed on the spindle housing so as to face the first coil means with a space therebetween, Including
A cutting apparatus, wherein the first flange member is provided with a plurality of ultrasonic transducers having different resonance frequencies connected in parallel with the first coil means. 2. The cutting apparatus according to claim 1, wherein the control means analyzes a waveform corresponding to a time change of the vibration signal by performing Fourier transform, and determines a change in the state of the cutting blade from a change in the vibration component.

Images