JP2007290046A - Cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool, in which a grindstone blade formed by fixing abrasive grains by means of various kinds of bonding agents can be installed, and the grindstone blade can be lapped to be finished in desired thickness for further improving production efficiency. <P>SOLUTION: The cutting tool comprises a vibration transmitting member installed on a rotary spindle provided with an ultrasonic vibration means, and the circular grindstone blade installed on the vibration transmission member. The vibration transmission member comprises a boss part installed on an end surface of the rotary spindle, and a circular blade mounting part formed to protrude diametrically from an axial center part of the boss part, having blade mounting surfaces at both end surfaces. The circular grindstone blades are fixed to the blade mounting surfaces respectively formed at the end surfaces of the blade mounting part by means of bonding agent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cutting tool provided with a grindstone blade, and more particularly to a cutting tool used in a cutting apparatus that cuts a workpiece such as a semiconductor wafer or an optical device wafer while applying ultrasonic vibration to the grindstone blade.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by dividing lines called streets arranged in a lattice pattern on the surface of a substantially wafer-shaped semiconductor wafer, and devices such as ICs, LSIs, etc. are partitioned in the partitioned regions. Form. Then, the semiconductor wafer is cut along the streets to divide the region in which the device is formed to manufacture individual semiconductor chips. In addition, optical device wafers with gallium nitride compound semiconductors laminated on the surface of sapphire substrates are divided into individual light emitting diodes, laser diodes, CCDs and other optical devices by cutting along the streets. It's being used.

  The above-described cutting along the wafer street is usually performed by a cutting device called a dicer. This cutting apparatus includes a chuck table for holding a workpiece such as a wafer, a cutting means for cutting the workpiece held on the chuck table, and a cutting for relatively moving the chuck table and the cutting means. And feeding means. The cutting means includes a spindle unit including a cutting tool including a rotary spindle and a grindstone blade mounted on the rotary spindle, and a drive mechanism for driving the rotary spindle to rotate. In such a cutting apparatus, the cutting tool and the work piece held on the chuck table are relatively cut and fed while rotating the cutting tool at a rotational speed of 20000 to 40000 rpm.

  However, brittle hard materials such as silicon, sapphire, silicon nitride, glass, and lithium tantalate are used for the wafer on which the device is formed. There is a problem of lowering. Also, a wafer with high Mohs hardness such as sapphire is very difficult if not impossible to cut with a grindstone blade.

In order to solve the above-described problems, an ultrasonic vibrator is disposed on a rotating spindle on which a cutting tool equipped with a grinding wheel blade is mounted, and an AC voltage is applied to the ultrasonic vibrator, thereby superposing the grinding wheel blade. There has been proposed a cutting method in which cutting is performed while applying sonic vibration. (For example, refer to Patent Document 1.)
Japanese Patent No. 3469516

A cutting tool used in the above-described cutting method includes a vibration transmission member attached to a rotary spindle, and a grindstone blade in which abrasive grains such as diamond are fixed to the vibration transmission member by nickel plating. Thus, by using the integrated cutting tool with the grinding wheel blade fixed to the vibration transmitting member by plating, ultrasonic vibration can be reliably transmitted to the grinding wheel blade. However, a grindstone blade in which abrasive grains such as diamond are fixed by nickel plating is not necessarily suitable for cutting all workpieces. Depending on the material of the workpiece, a resin bond grindstone in which abrasive grains are bonded by resin bonds. It is desirable to be able to select a blade, a metal bond grindstone blade in which abrasive grains are bonded by metal bond, and a vitrified bond grindstone blade in which abrasive grains are bonded by vitrified bond.
Further, when it is desired to finish the thickness of the grindstone blade to a desired thickness, the grindstone blade is sandwiched between the bottom plate and the upper plate and lapping is performed, for example, a grindstone blade having a thickness of 50 μm is 45 μm. However, the grindstone blade fixed to the vibration transmission member by plating has a problem that the vibration transmission member becomes an obstacle and cannot be lapped.
Furthermore, since the cutting tool described above is configured to form a grindstone blade by fixing abrasive grains to one surface of the vibration transmission member by nickel plating, the number of grindstone blades is one. Therefore, when the device formed on the wafer is small and the street interval between the devices is small, the number of streets to be cut is large, so that the number of times of cutting is increased and the production efficiency is low.

  The present invention has been made in view of the above facts, and the main technical problem thereof is that a grindstone blade formed by fixing abrasive grains with various bonding agents can be mounted, and the grindstone blade is lapped. It is another object of the present invention to provide a cutting tool that can be finished to a desired thickness and can further improve production efficiency.

In order to solve the above-mentioned main technical problem, according to the present invention, cutting comprising a vibration transmission member attached to a rotary spindle provided with ultrasonic vibration means and an annular grindstone blade attached to the vibration transmission member. A tool,
The vibration transmission member includes a boss portion to be mounted on an end surface of the rotary spindle, and an annular blade mounting portion formed so as to project radially from a central portion in the axial direction of the boss portion and provided with blade mounting surfaces on both end surfaces. Consists of
An annular grindstone blade is fixed to each of the blade mounting surfaces formed on both end surfaces of the annular blade mounting portion by a bond agent, respectively.
A cutting tool is provided.

The width H (mm) between the blade attachment surfaces formed on both end faces of the annular blade attachment portion is set to 2 to 6 mm.
In addition, when the width for cutting the workpiece is X, the width between the blade mounting surfaces is set to an integer multiple (n · X) of the width X for cutting the workpiece. .

  The cutting tool according to the present invention is configured so that the annular grindstone blade is fixed to the annular blade mounting portion of the vibration transmission member with a bonding agent, and therefore, the grindstone blade formed by fixing abrasive grains with various bonding agents is mounted. can do. Further, the annular grinding wheel blade can be finished to a desired thickness by lapping before being fixed to the annular blade mounting portion of the vibration transmitting member with a bonding agent. Furthermore, in the cutting tool according to the present invention, since the annular grindstone blades are respectively fixed to the blade mounting surfaces formed on the both end surfaces of the annular blade mounting portion of the vibration transmitting member by the bonding agent, two cutting tools are simultaneously cut. Grooves can be formed, and production efficiency can be improved.

  Hereinafter, a preferred embodiment of a cutting tool constructed according to the present invention will be described in more detail with reference to the accompanying drawings.

  FIG. 1 shows a perspective view of a cutting apparatus equipped with a cutting tool constructed according to the present invention. The cutting device in the illustrated embodiment includes a device housing 2 having a substantially rectangular parallelepiped shape. In the apparatus housing 2, a chuck table 3 for holding a workpiece is disposed so as to be movable in a direction indicated by an arrow X that is a cutting feed direction. The chuck table 3 includes a suction chuck support 31 and a suction chuck 32 disposed on the suction chuck support 31. A workpiece is illustrated on a holding surface which is the upper surface of the suction chuck 32. Suction holding is performed by operating a suction means that does not. The chuck table 3 is configured to be rotatable by a rotation mechanism (not shown). The chuck table 31 is provided with a clamp 33 for fixing a support frame that supports a wafer, which will be described later, via a protective tape as a workpiece. The chuck table 3 configured as described above can be moved in a cutting feed direction indicated by an arrow X by a cutting feed means (not shown).

  The cutting apparatus shown in FIG. 1 includes a spindle unit 4 as cutting means. The spindle unit 4 is mounted on a moving base (not shown) and is moved in an indexing direction indicated by an arrow Y perpendicular to the cutting feed direction indicated by the arrow X by indexing feeding means (not shown), and a cutting direction by a notch feeding means (not shown). It can be moved in the direction indicated by the arrow Z. The spindle unit 4 will be described with reference to FIG.

  The spindle unit 4 shown in FIG. 2 includes a spindle housing 41, a rotary spindle 42 that is rotatably disposed in the spindle housing 41, and a cutting tool 43 that is attached to the tip of the rotary spindle 42. . The spindle housing 41 is formed in a substantially cylindrical shape and includes a shaft hole 411 penetrating in the axial direction. A rotary spindle 42 that is inserted through a shaft hole 411 formed in the spindle housing 41 includes a tool mounting portion 422 provided with a screw hole 421 at a front end portion thereof, and a central portion thereof in a radial direction. A protruding thrust bearing flange 423 is provided. In this way, the rotary spindle 42 disposed through the shaft hole 411 formed in the spindle housing 41 is rotatably supported by high-pressure air supplied between the inner wall of the shaft hole 411.

The cutting tool 43 attached to the tool attachment portion 422 provided at the tip of the rotary spindle 42 includes a vibration transmission member 44 attached to the end face of the tool attachment portion 422 and the vibration transmission as shown in FIGS. It consists of two annular grinding wheel blades 45a and 45b attached to the member 44.
The vibration transmitting member 44 includes a boss portion 441 that is mounted on the tool mounting portion 422 of the rotary spindle 42 and an annular blade mounting portion 442 that is formed so as to protrude in the radial direction from the outer peripheral surface of the boss portion 441. . The boss portion 441 has a through hole 441a at the center of the axis. The blade attachment portion 422 is formed so as to protrude in the radial direction from the axial central portion of the boss portion 441, and the position restricting portions into which the openings 451 of the grindstone blades 45a and 45b are fitted respectively on the inner peripheral sides of both end surfaces. 442a and 442b are provided to protrude by about 1 mm. Then, annular blade attachment surfaces 442c and 442d are formed on the outer peripheral sides of the position restricting portions 442a and 442b on both end surfaces of the blade attachment portion 422, respectively. Note that the width H between the blade attachment surfaces 442c and 442d of the blade attachment portion 442 is efficient for vibration generated by vibration generation means described later on the annular grinding wheel blades 45a and 45b attached to the blade attachment surfaces 442c and 442d. It is set to 2-6 mm for transmission. According to the experiments by the present inventors, it has been found that if the width H between the blade mounting surfaces 442c and 442d is less than 2 mm and 6 mm or more, vibration cannot be efficiently transmitted to the annular grinding wheel blades 45a and 45b. The width H between the blade attachment surfaces 442c and 442d is set corresponding to the cutting width of the workpiece, and when the cutting width of the workpiece is X, the width H between the blade attachment surfaces 442c and 442d. (mm) is set to an integral multiple of X (n · X), where X is the width of cutting the workpiece.

  The annular grindstone blades 45a and 45b are each composed of an outer peripheral cutting edge portion 452 and an inner peripheral fixing portion 453. In the illustrated embodiment, the annular grindstone blades 45a and 45b are formed into an annular shape by bonding abrasive grains to one surface of an annular aluminum plate by metal plating such as nickel and then removing the aluminum plate by etching. The formed electroformed blade, the resin bonded blade formed by bonding the abrasive grains with resin bonds, the metal bonded blade formed by bonding the abrasive grains with metal bonds, and the abrasive grains bonded by vitrified bonds A vitrified bond blade formed in an annular shape can be used. The annular grinding wheel blades 45a and 45b are preferably lapped and finished to a desired thickness before being fixed to the vibration transmission member 44. Such annular grindstone blades 45a and 45b are fixed to the blade mounting surfaces 442c and 442d of the blade mounting portion 442 constituting the vibration transmitting member 44 by fixing parts 453 and 453 at the inner peripheral portion with an epoxy or acrylic bond agent, respectively. Is fixed. At this time, the annular grindstone blades 45a and 45b are attached to the position restricting portions 442a and 442b by fitting the openings 451 and 451 of the annular grindstone blades 45a and 45b, respectively, so that the blade attachment portion 422 of the vibration transmitting member 44 is attached to the blade. It is securely fixed to the surfaces 442c and 442d. In addition, it is desirable that the fixed side surfaces (surfaces to which the bonding agent is applied) of the fixed portions 453 and 453 of the annular grindstone blades 45a and 45b are formed to be rough surfaces.

  In the cutting tool 43 configured as described above, the annular grindstone blades 45a and 45b are fixed to the blade mounting surfaces 442c and 442d of the blade mounting portion 442 constituting the vibration transmitting member 44 by a bonding agent, respectively. 43 is symmetrical with respect to the axial center. As shown in FIG. 2, the cutting tool 43 configured in this manner is provided with a tightening bolt 46 inserted through a through hole 441a formed in a boss portion 441 of the vibration transmitting member 44 and mounted on the rotary spindle 42 as a tool. By screwing into a screw hole 421 provided in the portion 422, it is mounted on the end surface of the rotary spindle 42. When the cutting tool 43 is mounted on the tool mounting portion 422 of the rotary spindle 42, the space between the tool mounting portion 422 and the boss portion 441 of the vibration transmitting member 44 and between the boss portion 441 and the head of the tightening bolt 46 are included. Between the spacers 47 and 47 made of synthetic resin are interposed.

  The spindle unit 4 in the illustrated embodiment includes an electric motor 5 for driving the rotary spindle 42 to rotate. The illustrated electric motor 5 is constituted by a permanent magnet motor. The permanent magnet type electric motor 5 is disposed in the spindle housing 41 on the outer peripheral side of the rotor 51 and a rotor 51 made of a permanent magnet mounted on a motor mounting portion 424 formed in an intermediate portion of the rotary spindle 42. The stator coil 52 is included. In the electric motor 5 configured in this manner, the rotor 51 is rotated by applying AC power to the stator coil 52 by power supply means described later, and the rotating spindle 42 to which the rotor 51 is mounted is rotated.

  The spindle unit 4 in the illustrated embodiment includes an ultrasonic transducer 6 that is disposed on the rotary spindle 42 and applies ultrasonic vibration to the cutting tool 43. The ultrasonic vibrator 6 includes an annular piezoelectric body 61 polarized in the axial direction of the rotary spindle 42 and two annular electrode plates 62 and 63 attached to both side polarization surfaces of the piezoelectric body 61. It has become. The piezoelectric body 61 is made of piezoelectric ceramics such as barium titanate, lead zirconate titanate, and lithium tantalate. The ultrasonic transducer 6 configured as described above is mounted on the rotary spindle 42, and generates ultrasonic vibration when AC power having a predetermined frequency is applied to the electrode plates 62 and 63 by power supply means described later. A plurality of ultrasonic transducers 6 may be arranged in the axial direction.

The spindle unit 4 in the illustrated embodiment includes power supply means 7 that applies AC power to the ultrasonic vibrator 6 and applies AC power to the electric motor 5.
The power supply means 7 includes a rotary transformer 8 disposed at the rear end of the spindle unit 4. The rotary transformer 8 includes a power receiving unit 81 disposed at the rear end of the rotary spindle 42 and a power feeding unit 82 disposed opposite to the power receiving unit 81 and disposed at the rear end portion of the spindle housing 41. is doing. The power receiving means 81 includes a rotor side core 811 attached to the rotary spindle 42 and a power receiving coil 812 wound around the rotor side core 811. One end of the power receiving coil 812 of the power receiving means 81 configured in this way is connected to the electrode plate 61 of the ultrasonic transducer 6, and the other end is connected to the electrode plate 62. The power supply means 82 includes a stator side core 821 disposed on the outer peripheral side of the power reception means 81 and a power supply coil 822 disposed on the stator side core 821. The power supply coil 822 of the power supply means 82 configured in this way is supplied with AC power via the electrical wirings 73 and 74.

  The power supply means 7 in the illustrated embodiment includes an AC power supply 91 for AC power supplied to the power supply coil 822 of the rotary transformer 8, a voltage adjustment means 92 as power adjustment means, and AC power supplied to the power supply means 82. Frequency adjusting means 93 for adjusting the frequency of the power, control means 94 for controlling the voltage adjusting means 92 and the frequency adjusting means 93, and the amplitude of ultrasonic vibration applied to the grindstone blades 45a and 45b to the control means 94. Input means 95 is provided. The power supply means 7 shown in FIG. 2 supplies AC power to the stator coil 52 of the electric motor 5 through the control circuit 96 and the electric wirings 521 and 522.

The spindle unit 4 in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
When performing the cutting operation, AC power is supplied from the power supply means 7 to the stator coil 52 of the electric motor 5. As a result, the electric motor 5 rotates and the rotating spindle 42 rotates, and the blade mounting surfaces 442c and 442d of the blade mounting portion 442 constituting the vibration transmitting member 44 of the cutting tool 43 attached to the tip of the rotating spindle 42 are applied. The fixed grinding wheel blades 45a and 45b are rotated.

  On the other hand, the power supply means 7 controls the voltage adjusting means 92 and the frequency converting means 93 by the control means 94 to control the voltage of the AC power to a predetermined voltage, and the frequency of the AC power is set to a predetermined frequency (for example, 20 kHz). And is supplied to the power supply coil 822 of the power supply means 82 constituting the rotary transformer 8. When AC power having a predetermined frequency is applied to the feeding coil 822 as described above, AC power having a predetermined frequency is interposed between the electrode plate 62 and the electrode plate 63 of the ultrasonic transducer 6 via the power receiving coil 812 of the rotating power receiving means 81. Is applied. As a result, the ultrasonic transducer 6 is repeatedly displaced in the radial direction and vibrates ultrasonically. This ultrasonic vibration is transmitted to the vibration transmission member 44 of the cutting tool 43 via the rotary spindle 42, and the vibration transmission member 44 ultrasonically vibrates in the radial direction. Therefore, the grindstone blades 45a and 45b mounted on the blade mounting surfaces 442c and 442d of the blade mounting portion 442 constituting the vibration transmitting member 44 are ultrasonically vibrated in the radial direction. At this time, the cutting tool 43 is configured to be bilaterally symmetric with respect to the axial center as described above, so that it accurately ultrasonically vibrates in the radial direction without shaking left and right.

  Returning to FIG. 1, the description will continue. The cutting apparatus in the illustrated embodiment images the surface of the workpiece held on the chuck table 3 and detects the area to be cut by the grinding wheel blades 45a and 45b. Alignment means 12 is provided. The alignment unit 12 includes an imaging unit including an optical unit such as a microscope or a CCD camera. In addition, the cutting apparatus includes a display unit 13 that displays an image or the like captured by the alignment unit 12.

  In the cassette mounting area 14a of the apparatus housing 2, a cassette mounting table 14 for mounting a cassette for storing a workpiece is disposed. The cassette mounting table 14 is configured to be movable in the vertical direction by lifting means (not shown). On the cassette mounting table 14, a cassette 15 for storing the workpiece 100 is mounted. The workpiece 100 accommodated in the cassette 15 has a grid-like street formed on the surface of the wafer, and devices such as capacitors, LEDs, and circuits are formed in a plurality of rectangular areas partitioned by the grid-like street. Has been. The workpiece 100 formed in this way is accommodated in the cassette 15 with the back surface adhered to the surface of the protective tape 120 attached to the annular support frame 110.

  Further, the cutting device in the illustrated embodiment is a state in which the workpiece 100 (supported on the annular frame 110 via the protective tape 120) is accommodated in the cassette 15 placed on the cassette placement table 14. ) To the temporary table 16, to the workpiece table 100 conveyed to the chuck table 3, and to the workpiece cut on the chuck table 3. A cleaning unit 19 for cleaning the workpiece 100 and a cleaning / conveying unit 20 for conveying the workpiece 100 cut on the chuck table 3 to the cleaning unit 19 are provided.

The operation of the cutting apparatus configured as described above will be briefly described mainly with reference to FIG.
The workpiece 100 accommodated in a predetermined position of the cassette 15 placed on the cassette placement table 14 is positioned at the unloading position by the vertical movement of the cassette placement table 14 by an unillustrated lifting means. Next, the unloading means 17 moves forward and backward to unload the workpiece 100 positioned at the unloading position onto the temporary placement table 16. The workpiece 100 carried out to the temporary placement table 16 is transferred onto the chuck table 3 by the turning operation of the transfer means 18. When the workpiece 100 is placed on the chuck table 3, suction means (not shown) is operated to suck and hold the workpiece 100 on the chuck table 3. The annular frame 110 that supports the workpiece 100 via the protective tape 120 is fixed by the clamp 33. The chuck table 3 holding the workpiece 100 in this way is moved to a position immediately below the alignment means 12. When the chuck table 3 is positioned immediately below the alignment means 12, the street formed on the workpiece 100 is detected by the alignment means 12, and the spindle unit 4 is moved and adjusted in the direction of the arrow Y which is the indexing direction. The precision alignment operation | work with the grindstone blades 45a and 45b of the cutting tool 43 is performed.

Here, the state in which the street formed on the workpiece and the grindstone blades 45a and 45b of the cutting tool 43 are aligned will be described with reference to FIG.
As shown in FIG. 4, the interval (cutting width) S between the streets 102 defining the device 101 formed on the surface of the workpiece 100 held on the chuck table 3 is set to 1 mm, and the grindstone blade 45a of the cutting tool 43 is used. And 45b (the width between the blade mounting surfaces 442c and 442d of the blade mounting portion 442) is 4 mm, the grindstone blades 45a and 45b are positioned opposite to the streets 102 and 102 with the four devices 101 interposed therebetween. Positioned.

  Thereafter, the cutting tool 43 is cut and fed by a predetermined amount in the direction indicated by the arrow Z in FIG. The workpiece 100 held on the chuck table 3 is simultaneously cut along the two streets 102 and 102 by the two grindstone blades 45a and 45b. In this cutting step, AC power having a frequency of 20 kHz and a voltage of 55 V is applied to the ultrasonic transducer 6 by the power supply means 7. As a result, as described above, the ultrasonic transducer 6 is ultrasonically vibrated by being repeatedly displaced in the radial direction. This ultrasonic vibration is transmitted to the vibration transmission member 44 of the cutting tool 43 via the rotary spindle 42, and the vibration transmission member 44 ultrasonically vibrates in the radial direction. Therefore, the grindstone blades 45a and 45b fixed to the vibration transmitting member 44 vibrate ultrasonically in the radial direction. For this reason, since the cutting resistance by the grindstone blades 45a and 45b is reduced, even if the workpiece 100 is a difficult-to-cut material such as sapphire, it can be easily cut.

The perspective view of the cutting device with which the cutting tool comprised according to this invention was mounted | worn. Sectional drawing of the spindle unit with which the cutting apparatus shown in FIG. 1 is equipped. Sectional drawing which expands and shows the cutting tool by this invention. Explanatory drawing which shows the state which aligned the grindstone blade which comprises the cutting tool shown in FIG. 3, and the cutting area of a workpiece.

Explanation of symbols

2: Device housing 3: Chuck table mechanism 30: Chuck table 4: Spindle unit 41: Spindle housing 42: Rotary spindle 43: Cutting tool 44: Vibration transmission member 441: Boss portion of vibration transmission member 442: Blade attachment of vibration transmission member 45a, 45b: Grinding wheel blade 46: Clamping bolt 5: Electric motor 6: Ultrasonic vibrator 7: Power supply means 8: Rotary transformer 81: Power receiving means 82: Power supply means 91: AC power supply 92: Voltage adjustment means 93: Frequency Adjustment means 94: Control means 95: Input means 12: Alignment means 13: Display means 15: Cassette 16: Temporary placement table 17: Unloading means 18: Conveying means 19: Cleaning means 20: Cleaning and conveying means

Claims (3)

A cutting tool comprising a vibration transmission member attached to a rotating spindle provided with ultrasonic vibration means, and an annular grindstone blade attached to the vibration transmission member,
The vibration transmission member includes a boss portion to be mounted on an end surface of the rotary spindle, and an annular blade mounting portion formed so as to project radially from a central portion in the axial direction of the boss portion and provided with blade mounting surfaces on both end surfaces. Consists of
An annular grindstone blade is fixed to each of the blade mounting surfaces formed on both end surfaces of the annular blade mounting portion by a bond agent, respectively.
A cutting tool characterized by that.   The cutting tool according to claim 1, wherein a width H (mm) between the blade mounting surfaces formed on both end surfaces of the annular blade mounting portion is set to 2 to 6 mm.   When the width for cutting the workpiece is X, the width between the blade mounting surfaces is set to an integral multiple (n · X) of the width X for cutting the workpiece. Item 3. The cutting tool according to Item 2.

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