CN100593454C - Cutting tool - Google Patents

Abstract

The present invention provides a cutting tool capable of mounting a grinding wheel sheet formed by fixing abrasive grains with various adhesives, and capable of grinding the grinding wheel sheet to a desired thickness. This cutting tool is mounted on a rotating spindle provided with an ultrasonic vibration mechanism, and has: a vibration transmission member mounted on the above-mentioned rotating spindle; The grinding wheel piece has a cutting edge portion on the outer periphery and a fixing portion on the inner periphery, and the fixing portion is fixed to the mounting portion of the vibration transmission member by an adhesive.

Description

cutting tool

technical field

The present invention relates to a cutting tool having a grinding wheel, and more specifically to a cutting tool used in a cutting device for cutting workpieces such as semiconductor wafers and optical device wafers while applying ultrasonic vibrations to the grinding wheel.

Background technique

In the semiconductor device manufacturing process, on the surface of a substantially wafer-shaped semiconductor wafer, the surface is divided into a plurality of subdivision lines by the so-called scribing lines arranged in a grid pattern, and formed in the divided areas. IC, LSI and other devices. Then, the semiconductor wafer is diced along dicing lines to be divided into regions in which devices are formed, and individual semiconductor chips are produced. In addition, on the surface of the sapphire substrate, the laminated optical device wafers such as gallium nitride-based compound semiconductors are also diced along the scribing line, and divided into individual optical devices such as light-emitting diodes, laser diodes, and CCDs, which are widely used in electrical equipment. .

Slicing along the scribing line of the wafer is usually performed by a cutting device called a dicing blade. The cutting device includes an adsorption table holding a workpiece such as a wafer, a cutting mechanism for cutting the workpiece held by the adsorption table, and a cutting transfer mechanism for relatively moving the adsorption table and the cutting mechanism. The cutting mechanism includes: a cutting tool having a rotating main shaft and a grinding wheel mounted on the rotating main shaft; and a main shaft unit having a drive mechanism for rotationally driving the rotating main shaft. In such a cutting device, while rotating the cutting tool at a rotational speed of 20,000 to 40,000 rpm, the cutting tool and the workpiece held on the adsorption table are opposed to be cut and conveyed.

Nevertheless, silicon, sapphire, silicon nitride, glass, lithium tantalate and other brittle and hard materials are used to form the wafer of the device. If the grinding wheel is used for cutting, there is a problem that gaps are generated on the cut surface, which reduces the quality of the device. Moreover, although it is not impossible to cut wafers with high Mohs hardness such as sapphire with a grinding wheel, it is actually very difficult.

In order to solve the above problems, such a cutting method has been proposed, that is, an ultrasonic vibrator is installed on the rotating spindle of a cutting tool with a grinding wheel, and by applying an AC voltage to the ultrasonic vibrator, ultrasonic vibration is applied to the grinding wheel. Cutting (for example, see Patent Document 1 (Japanese Patent No. 3469516)).

The cutting tool used in the above-mentioned cutting method is composed of a vibration transmission member mounted on a rotating spindle, and a grinding wheel plate on which abrasive grains such as diamond are fixed to the vibration transmission member by nickel plating. In this way, the ultrasonic vibration can be reliably transmitted to the grinding wheel by using the cutting tool in which the grinding wheel is fixed to the vibration transmitting member through electroplating and integrated. However, not limited to the use of nickel plating to fix diamond and other abrasive grains, it is suitable for cutting all workpieces. It is best to choose a resin bonded grinding wheel that binds abrasive grains with a resin bond according to the material of the workpiece. , a metal bonded grinding wheel that uses a metal bond to bond abrasive grains, and a vitrified bonded grinding wheel that uses a vitrified bond to bond abrasive grains.

And, when it is desired to trim the thickness of the grinding wheel to the required thickness, the grinding wheel is clamped between the chassis and the upper plate for grinding, and the thickness of the grinding wheel, for example, 50 μm, can be corrected to a thickness of 45 μm. However, there is a problem that in the grinding wheel piece fixed to the vibration transmission member by electroplating, the vibration transmission member becomes an obstacle, and the grinding process cannot be performed.

Contents of the invention

The present invention is a proposal in view of the above-mentioned situation, and its main purpose is to provide a cutting tool that can mount a grinding wheel sheet formed by fixing abrasive grains with various adhesives, and can fix the grinding wheel The sheet is ground and trimmed to the required thickness.

In order to solve the above-mentioned main technical problems, a cutting tool, mounted on a rotating spindle provided with an ultrasonic vibration mechanism, is characterized in that:

It has: a vibration transmission member installed on the above-mentioned rotating main shaft; and an annular grinding wheel piece installed on the above-mentioned vibration transmission member and has an opening in the center,

The above-mentioned grinding wheel piece has a cutting edge portion on the outer peripheral portion and a fixing portion on the inner peripheral portion, and the fixing portion is fixed to the mounting portion of the above-mentioned vibration transmission member by an adhesive,

Preferably, the hardness of the above-mentioned adhesive is set to Shore D60 or higher.

Preferably, the mounting portion of the vibration transmission member is provided with a position regulating portion that fits into the opening of the grinding wheel piece.

Invention effect

The cutting tool of the present invention utilizes adhesives to fix the fixing portion of the inner peripheral portion of the annular grinding wheel piece to the mounting portion of the vibration transmission member, so it can be used for grinding wheels formed by fixing abrasive grains with various adhesives. sheet to install. In addition, before the annular grinding wheel piece is fixed to the attachment portion of the vibration transmission member with an adhesive, it can be trimmed to a desired thickness by grinding.

Description of drawings

Fig. 1 is a perspective view of a cutting device equipped with a cutting tool according to the present invention.

Fig. 2 is a cross-sectional view of a spindle unit mounted on the cutting device shown in Fig. 1 .

3 is an explanatory diagram showing a release agent coating step in a method of fixing a grinding wheel piece to a vibration transmission member constituting the cutting tool of the present invention.

4 is an explanatory view showing an adhesive coating step and an insert bonding step in a method of fixing a grinding wheel sheet to a vibration transmission member constituting the cutting tool according to the present invention.

Fig. 5 is an explanatory view showing a pressure bonding step in a method of fixing a grinding wheel sheet to a vibration transmission member constituting the cutting tool of the present invention.

6 is a graph showing the relationship between the hardness of an adhesive bonding a grinding wheel piece to a vibration transmitting member and the amplitude of ultrasonic vibration applied to the grinding wheel piece.

Detailed ways

A preferred embodiment of the cutting tool according to the present invention will be described in more detail below with reference to the accompanying drawings.

Fig. 1 is a perspective view of a cutting device equipped with a cutting tool according to the present invention. The cutting device of the illustrated embodiment has a substantially rectangular parallelepiped-shaped device case 2 . In the apparatus casing 2, a suction table 3 holding a workpiece is provided so as to be movable in the direction of arrow X in the cutting conveyance direction. The suction table 3 has a suction cup support 31 and a suction cup 32 provided on the suction cup support 31 , and absorbs and holds the workpiece on the holding surface above the suction cup 32 by the operation of a suction mechanism not shown. In addition, the suction table 3 is rotatable by a rotation mechanism not shown. Furthermore, a holder 33 is provided on the suction table 31 for fixing a support frame so as to support a wafer to be processed described below via a protective tape. The suction table 3 configured in this way can move in the cutting conveying direction indicated by the arrow X by means of a cutting conveying mechanism not shown.

The cutting device shown in FIG. 1 has a spindle unit 4 as a cutting mechanism. The main shaft unit 4 is mounted on an unillustrated movable base, and moves in an indexing direction indicated by an arrow Y perpendicular to the cutting feed direction indicated by the above-mentioned arrow X through an unillustrated indexing feed mechanism. ; And move in the direction shown by the arrow Z in the cutting direction by the cutting feed mechanism not shown in the figure. The spindle unit 4 will be described below with reference to FIG. 2 .

The spindle unit 4 shown in FIG. 2 has: a spindle housing 41 ; a rotary spindle 42 rotatably provided in the spindle housing 41 ; and a cutting tool 43 attached to the front end of the rotary spindle 42 . The main shaft housing 41 is substantially cylindrical and has a shaft hole 411 penetrating in the axial direction. The rotary spindle 42 inserted through the shaft hole 411 formed in the spindle housing 41 has a tool mounting portion 422 with a threaded hole 421 at its front end, and a stopper 422 protruding radially at its center. Push bearing flange 423. Thus, the rotary spindle 42 inserted through the shaft hole 411 formed in the spindle housing 41 is rotatably supported by the high-pressure air supplied between the inner walls of the shaft hole 411 .

The cutting tool 43 mounted on the tool mounting part 422 includes a vibration transmission part 44 and an annular grinding wheel piece 45 mounted on the vibration transmission part 44 and has a circular opening 451 in the center. The mounting portion 422 is provided on the front end portion of the rotary spindle 42 . The vibration transmission member 44 has: a central large-diameter portion 441, a coaxial first small-diameter portion 442 protruding from one end surface 441a of the central large-diameter portion 411, and a coaxial first small-diameter portion 442 protruding from the other end surface 441b of the central large-diameter portion 441. Shaft-shaped second small-diameter portion 443 . One end surface 441a of the central large-diameter portion 441 becomes the mounting surface of the grinding wheel piece 45, and a position limiting portion 444 is provided on the one end surface 441a protruding about 1mm, and the position limiting portion 444 is used to fit into the opening 451 of the grinding wheel piece 45. . Furthermore, the first small-diameter portion 442 and the second small-diameter portion 443 have the same outer diameter and the same length. In the vibration transmission member 44 thus formed, a through-hole 445 passing through the center of the shaft is formed.

The annular grindstone 45 is composed of a cutting edge portion 452 on the outer periphery and a fixing portion 453 on the inner periphery. The annular grinding wheel piece 45 can adopt the following various blades: after the abrasive grains are bonded to one surface of the annular aluminum plate by metal plating such as nickel, the aluminum plate is etched and removed to form an annular electroformed blade ; Resin bonded blades that use a resin bond to bond abrasive grains to form a ring; metal bonded blades that use a metal bond to bond abrasive grains to form a ring; and use a vitrified bond to bond abrasive grains to form a ring Shaped ceramic bonded blades, etc. The ring-shaped grinding wheel piece 45 is fixed to the one end surface 441a which is the mounting surface of the central large-diameter portion 441 of the vibration transmission member 44 by using a suitable adhesive to fix the inner peripheral fixing portion 453 . At this time, the opening 451 of the grinding wheel piece 45 fits with the position limiting portion 444, and the grinding wheel piece 45 is reliably fixed on the mounting portion of the central large-diameter portion 441 of the vibration transmission member 44, that is, at a predetermined position on one end surface 441a.

Next, referring to FIGS. 3 to 5 , a method of fixing the grinding wheel piece 45 to the one end surface 441 a which is the attachment portion of the central large-diameter portion 441 of the vibration transmission member 44 will be described. Furthermore, before the grinding wheel piece 45 is fixed to the vibration transmission member 44, it is preferable to grind the grinding wheel piece 45 and trim it to a desired thickness.

In order that the grinding wheel piece 45 is fixed on the vibration transmission part 44, at first, as shown in Figure 3 (a), a face of the grinding wheel piece 45 is placed on an end face 441a of the central large-diameter part 441 of the vibration transmission part 44. At this time, the opening 451 of the grinding wheel piece 45 is fitted into the position regulating portion 444 . Then, as shown in Fig. 3 (b) and (c), the fitting portion between the opening 451 of the grinding wheel piece 45 and the position limiting portion 444 of the vibration transmission member 44, and the central large diameter portion 441 of the vibration transmission member 44 A release agent 456 is applied to the outer peripheral edge of the grinding wheel and the side surface of the grinding wheel sheet 45 in the vicinity of the outer peripheral edge (a release agent coating step).

Then, remove the grinding wheel piece 45 from the vibration transmission part 44 as shown in Figure 4 (a), and apply epoxy resin or acrylic to the mounting part of the central large-diameter part 441 of the vibration transmission 44, that is, an end surface 441a. agent 455 (adhesive application process). Moreover, it is preferable that the hardness of the adhesive 455 used in the cured state is above 60 according to JIS K 6253 Shore D hardness. And, as shown in FIG. 4( b ), a fixing portion 453 for bonding the grinding wheel piece 45 is attached to one end surface 441 a of the central large-diameter portion 441 coated with the adhesive 455 (blade bonding step). At this time, the opening 451 of the grindstone 45 is fitted into the position regulating portion 444 .

After the above-mentioned blade bonding step is performed, a pressurizing and fixing step is performed to pressurize the fixing portion 453 of the grinding wheel piece 45 and bond it to one end surface 441a of the mounting portion of the central large-diameter portion 441 of the vibration transmission member 44 . First, as shown in FIG. 5( a ), in the pressing and fixing process, the vibration transmission member 44 with the grinding wheel piece 45 bonded to one end surface 441 a of the central large-diameter portion 441 is placed on the pressing lower jig 10 . The press lower jig 10 is formed of a disk-shaped metal material, and a fitting hole 101 for fitting with the second small-diameter portion 443 of the vibration transmission member 44 is provided at the center thereof. The second small-diameter portion 443 of the vibration transmission member 44 is inserted into the fitting hole 101 of the pressure lower jig 10 configured in this way, and the central large-diameter portion 441 of the vibration transmission member 44 is attached to the pressure lower jig 10 .

As shown in Figure 5 (a), if the central large-diameter portion 441 of the vibration transmission part 44 is installed on the pressurized lower side clamp 10, then as shown in Figure 5 (b), on the vibration transmission part 44 and the grinding wheel piece 45 The pressurized upper jig 11 is installed. The pressurizing upper jig 11 is the same as the above-mentioned pressurizing lower jig 10. It is formed of a disc-shaped metal material, and a fitting hole 111 is provided in the center thereof to communicate with the first small-diameter portion 442 of the vibration transmission member 44. Chimeric. Further, on the lower surface of the pressurizing upper jig 11 in FIG. The diameter of the peripheral wall of the concave portion 112 is formed slightly larger than the diameter of the position restricting portion 444 . By fitting the fitting hole 111 of the press upper jig 11 configured in this way into the first small diameter portion 442 of the vibration transmission member 44, the lower surface of the press lower jig 11 is placed on the central large diameter portion of the vibration transmission member 44. 441 on the upper surface of the bonded grinding wheel sheet 45 in Figure 5 (b).

Moreover, in Fig. 5(a) and (b) of the press lower jig 10, by providing a recess 102 on the lower surface, the size of which is the same as that of the recess 112 provided on the press upper jig 11, the press lower jig 10 and the press upper jig 11 have the same shape, and these two jigs can be used for either the lower jig or the upper jig. Furthermore, by providing the recesses 102 on the top and bottom of the pressurization lower jig 10 and the recesses 112 on the top and bottom of the pressurization upper jig 11, the above operations can be performed even if they are turned upside down.

Then, as shown in FIG. 5( b ), the pressurization lower jig 10 and the pressurization upper jig 11 are pressurized for about 12 hours at a predetermined pressure (for example, 0.4 to 0.5 MPa). As a result, the fixed part 452 of the grinding wheel piece 45 utilizes the adhesive 445 (see FIG. 4( a)) that is coated on one end surface 441a of the central large diameter portion 441 of the vibration transmission member 44, and is bonded to the central large diameter. On one end surface 441a of the part 441 (pressure bonding process). At this time, due to the above-mentioned pressurization, the adhesive 455a overflows from the fitting portion of the opening 451 of the grinding wheel piece 45 and the position regulating portion 444 of the vibration transmission member 44, and the outer peripheral edge of the central large diameter portion 441 of the vibration transmission member 44. , the overflowing adhesive 455a adheres to the peeling agent 456 applied on the outer peripheral edge portion of the central large-diameter portion 441 of the above-mentioned grinding wheel piece 45 and the vibration transmission member 44 (see (b) and (c) of FIG. 3 ) superior. Therefore, after removing the cutting tool 45 from the pressurized lower jig 10 and the pressurized upper jig 11, by peeling the above-mentioned release agent 456, as described above, the overflowing adhesive 455a can also be removed. In the cutting tool 45 , the grinding wheel piece 45 is bonded to one end surface 441 a of the central large-diameter portion 441 of the vibration transmission member 44 .

Returning to FIG. 2 to continue the description, the cutting tool 43 with the above structure is mounted on the rotary spindle by screwing the fastening bolt 46 inserted into the through hole 445 with the threaded hole 421 provided on the tool mounting portion 422 of the rotary spindle 42. 42 on. Furthermore, when the cutting tool 43 is mounted on the tool mounting portion 422 of the rotary spindle 42, between the tool mounting portion 422 and the first small-diameter portion 442 and between the second small-diameter portion 443 and the head of the fastening bolt 46 , Liners 47, 47 made of synthetic resin are sandwiched.

The spindle unit 4 of the illustrated embodiment has a motor 5 for rotationally driving a rotary spindle 42 . The illustrated electric motor 5 is constituted by a permanent magnet motor. The permanent magnet motor 5 has: a rotor 51 made of permanent magnets mounted on a motor mounting portion 424 formed in the middle portion of the rotating main shaft 42; superior. The motor 5 configured in this way rotates the rotor 51 by applying AC power to the stator coil 52 by the power supply mechanism described below, and rotates the rotary spindle 4 to which the rotor 51 is mounted.

The spindle unit 4 of the illustrated embodiment has an ultrasonic vibrator 6 for applying ultrasonic vibration to a grinding wheel piece 45 provided on a rotating spindle 42 . The ultrasonic vibrator 6 has: an annular piezoelectric body 61 polarized in the axial direction of the rotating main shaft 42; and two annular electrode plates 62, 63 mounted on both sides of the piezoelectric body 61. surface. The piezoelectric body 61 is made of piezoelectric ceramics such as barium titanate, lead zirconate titanate, lithium tantalate, or the like. When the ultrasonic vibrator 6 configured in this way is attached to the rotating spindle 42, and AC power of a predetermined frequency is applied to the electrode plates 62 and 63 by the power supply mechanism described below, ultrasonic vibrations are generated. Furthermore, a plurality of ultrasonic vibrators 6 may be provided in the axial direction.

The spindle unit 4 of the illustrated embodiment has a power supply mechanism 7 for applying AC power to the ultrasonic vibrator 6 and for applying AC power to the motor 5 .

The power supply mechanism 7 has a resolver 8 provided at the rear end of the spindle unit 4 . The resolver 8 has a power receiving mechanism 81 provided on the rear end of the rotating main shaft 42 ; The power receiving mechanism 81 has: a rotor-side magnetic core 811 attached to the rotating main shaft 42 ; and a power receiving coil 812 wound around the rotor-side magnetic core 811 . One end of the power receiving coil 812 of the power receiving mechanism 81 configured in this way is connected to the electrode plate 61 of the ultrasonic vibrator 6 , and the other end is connected to the electrode plate 62 . The above-mentioned power supply mechanism 82 has: a stator-side magnetic core 821 arranged on the outer peripheral side of the power receiving mechanism 81; and a power supply coil 822 arranged on the stator-side magnetic core 821. AC power is supplied through electrical wiring 73 , 74 .

The power supply mechanism 7 of the illustrated embodiment includes: an AC power supply 91 for supplying power to the power supply coil 822 of the resolver 8; a voltage adjustment mechanism 92 as a power adjustment mechanism; and a frequency adjustment mechanism 93 for Adjust the frequency of the AC power supplied to the above-mentioned power supply mechanism 82; the control mechanism 94 is used to control the voltage adjustment mechanism 92 and the frequency adjustment mechanism 93; and the input mechanism 95 is used to input the ultrasonic vibration applied to the cutting blade 45 to the control mechanism amplitude etc. Further, the power supply mechanism 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 electrical wirings 521 and 522 .

The spindle unit 4 of the illustrated embodiment is configured as described above, and its operation will be described below.

When performing a cutting operation, AC power is supplied from the power supply mechanism 7 to the stator coil 52 of the motor 5 . As a result, the motor 5 rotates, the rotating main shaft 42 rotates, and the grinding wheel piece 45 attached to the vibration transmission member 44 of the cutting tool 43 attached to the front end of the rotating main shaft 42 rotates.

On the other hand, the power supply mechanism 7 controls the voltage adjustment mechanism 92 and the frequency adjustment mechanism 93 through the control mechanism 94, controls the voltage of the AC power to a predetermined voltage, and converts the frequency of the AC power to a predetermined frequency (for example, 20kHz), It is supplied to the power supply coil 822 constituting the power supply mechanism 82 of the resolver 8 . When AC power of a predetermined frequency is applied to power feeding coil 822 in this way, AC power of a predetermined frequency is applied between electrode plate 62 and electrode plate 63 of ultrasonic vibrator 6 via power receiving coil 812 of rotating power receiving mechanism 81 . As a result, the ultrasonic vibrator 6 is repeatedly displaced in the radial direction to perform ultrasonic vibration. This ultrasonic vibration is transmitted to the vibration transmission member 44 of the cutting tool 43 by rotating the main shaft 42, and the vibration transmission member 44 performs ultrasonic vibration in the radial direction. Therefore, the grinding wheel piece 45 attached to the vibration transmitting member 44 vibrates ultrasonically in the radial direction. Furthermore, the amplitude of the ultrasonic vibration applied to the grinding wheel piece 45 is proportional to the amount of AC power applied to the ultrasonic vibrator 6 . However, the inventors of the present invention have found through experiments that the amplitude is stable when the applied voltage is 50v to 60v. In addition, it is known that the amplitude of the ultrasonic vibration applied to the grinding wheel piece 45 varies depending on the hardness of the above-mentioned adhesive in a cured state.

Referring to FIG. 6, the relationship between the hardness of the adhesive and the amplitude of the ultrasonic vibration applied to the grinding wheel piece 45 will be described in detail below.

FIG. 6 is an experimental result measured by preparing a plurality of cutting tools 43 in which a grinding wheel piece 45 composed of an electroformed blade is bonded to a vibration transmission member 44 using adhesives having different hardnesses, The cutting tools 43 were mounted on the rotating spindles 42 of the spindle unit 4 shown in FIG.

It can be judged from FIG. 6 that the vibration amplitude of the grinding wheel piece 45 bonded with an adhesive having a Shore hardness of D28.5 is about 1.5 μm. If the grinding wheel piece 45 is bonded with an adhesive having a Shore hardness of D60, the vibration amplitude of the grinding wheel piece 45 is about 4.5 μm. In addition, if the hardness of the adhesive is equal to or greater than Shore D70, the vibration amplitude of the grinding wheel piece 45 is equal to or greater than 5 μm. In ultrasonic vibration processing, it is preferable to use an adhesive with a Shore hardness of D60 or higher because the amplitude of the grinding wheel sheet that acts on the processing is preferably 4 μm or more.

Return to Figure 1 to continue the description. The cutting device of the illustrated embodiment has a positioning mechanism 12 for imaging the surface of the workpiece held on the suction table 3 and detecting the area to be cut by the grinding wheel piece 45 . The alignment mechanism 12 includes an imaging mechanism composed of an optical mechanism such as a microscope and a CCD camera. Furthermore, the cutting device has a display unit 13 for displaying an image captured by the alignment unit 12 and the like.

The cassette placement area 14a in the above-mentioned device casing 2 is provided with a cassette placement table 14 for placing a cassette containing a processed object. The cassette mounting table 14 is configured to be movable in the vertical direction by a lift mechanism (not shown). A cassette 15 for placing the workpiece 100 is placed on the cassette placement table 14 . The workpiece 100 placed in the cassette 15 has grid-like scribe lines formed on the surface of the wafer, and components such as capacitors, LEDs, and circuits are formed in a plurality of rectangular areas divided by the grid-like scribe lines. The workpiece 100 formed in this way is placed in the chip cassette 15 in a state where the back surface thereof is pasted on the surface of the protective tape 102 attached to the ring-shaped support frame 101 .

In addition, the cutting device of the illustrated embodiment has: a carrying out mechanism 17 for carrying out the workpiece 100 (supported on the ring frame 101 by the protective belt 102 ) onto the temporary placement table 16 ; The object is put into the film box 15 on the film box placement table 14; the transfer mechanism 18 is used to transfer the processed object 100 that has been moved out to the temporary placement table 16 to the above-mentioned adsorption table 3; the cleaning mechanism 19 is used for cleaning The workpiece 100 that has been cut on the adsorption table 3 ; and the cleaning and conveying mechanism 20 is used to transfer the workpiece 100 that has been cut on the adsorption table 3 to the cleaning mechanism 19 .

Hereinafter, the operation of the cutting device having the above structure will be briefly described with reference mainly to FIG. 1 .

The workpiece 100 placed in the predetermined position of the cassette 15 placed on the cassette mounting table 14 is positioned at the position of the processing object by moving the cassette mounting table 14 up and down using an elevating mechanism not shown in the figure. Move out of position. Then, the carry-out mechanism 17 moves forward and backward to carry out the workpiece 100 located at the carry-out position onto the temporary placement table 16 . The workpiece 100 carried out to the temporary storage table 16 is transferred to the above-mentioned adsorption table 3 by the rotation operation of the transfer mechanism 18 . When the workpiece 100 is placed on the adsorption table 3 , a suction mechanism (not shown) operates to adsorb the workpiece 100 on the adsorption table 3 . Furthermore, the support frame 101 supporting the workpiece 100 via the protective belt 102 is fixed by the clamper 33 described above. In this way, the suction table 3 holding the workpiece 100 is moved to directly under the alignment mechanism 11 . When the suction table 3 is positioned directly under the alignment machine 11, the alignment mechanism 12 detects the scribing line formed on the workpiece 100, and the spindle unit 4 is positioned at the arrow symbol Y as the indexing direction. Adjust the movement in the direction, and perform precise position alignment work on the scribing line and the grinding wheel piece 45 of the cutting tool 43.

Then, while the grinding wheel piece 45 is cut and fed by a predetermined amount in the direction indicated by the arrow symbol Z, and rotated in the predetermined direction, the suction table 3 holding the workpiece 100 by suction is placed in the direction indicated by the arrow X which is the cutting feed direction. In the indicated direction (direction perpendicular to the rotation axis of the grinding wheel piece 45), the movement is performed at a predetermined cutting feed rate. As a result, the semiconductor wafer 100 held on the suction table 3 is cut along a predetermined scribing line by the grindstone 45 . In this cutting step, AC power of, for example, a frequency of 20 kHz and a voltage of 55 v is applied to the ultrasonic vibrator 6 by the power supply mechanism 7 . As a result, as described above, the ultrasonic vibrator 6 is repeatedly displaced in the radial direction to vibrate ultrasonically. This ultrasonic vibration is transmitted to the vibration transmission member 44 of the cutting tool 43 through the rotating spindle 42, and the vibration transmission member 44 performs ultrasonic vibration in the radial direction. Therefore, the grinding wheel piece 45 attached to the vibration transmission member 44 vibrates ultrasonically in the radial direction. Therefore, the cutting resistance due to the grinding wheel piece 45 is reduced, so even if the wafer 100 is made of difficult-to-cut materials such as sapphire, it can be easily cut.

Claims (2)

1. A cutting tool mounted on a rotating spindle provided with an ultrasonic vibration mechanism, characterized in that: It has: a vibration transmission member installed on the above-mentioned rotating main shaft; and an annular grinding wheel piece installed on the above-mentioned vibration transmission member and has an opening in the center, The above-mentioned grinding wheel piece has a cutting edge portion on the outer peripheral portion and a fixing portion on the inner peripheral portion, and the fixing portion is fixed to the mounting portion of the above-mentioned vibration transmission member by an adhesive, The hardness of the above-mentioned adhesive in the cured state is above 60 according to JIS K 6253 Shore D hardness. 2. The cutting tool according to claim 1, wherein a position restricting portion is provided on the mounting portion of the vibration transmission member, and the position restricting portion is fitted into the opening of the grinding wheel piece.

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