JP7177334B2 - holding device - Google Patents

Description

The present invention relates to the technology of holding devices.

A wire saw has been known as an apparatus for slicing a silicon ingot into plate-shaped wafers, but in recent years, there is a technique for slicing a workpiece into thin plates using a wire electric discharge machining technique.

Patent Literature 1 discloses a technique of fixing ingot electrodes to both end surfaces of an ingot with a conductive adhesive and slicing the ingot halfway with a wire.

However, in wire electric discharge machining, machining is carried out by spraying or immersing the machining fluid into the workpiece, so during electric discharge machining, leakage of machining current from the exposed workpiece surface to the machining fluid becomes a problem. It affects the inter-electrode voltage, etc., and the slicing process may not be stable.

JP 2016-97497 A

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mechanism capable of preventing leakage of a machining current from a workpiece surface exposed during electric discharge machining by a wire.

The present invention is a holding device for use in wire electric discharge machining for holding a work piece while it is cut into a plurality of work pieces, comprising a current-carrying portion made of a conductive material and holding the work piece while the work piece is cut into a plurality of work pieces. A holding portion made of a conductive material and an insulating portion made of an insulating material are provided. A machining current is applied to the work while it is cut into pieces, the work is held on the first surface of the work using the holding part, and the second surface of the work, which is the back side of the first surface, is applied to the work. The second surface is covered with the insulating portion capable of preventing leakage from the surface of the workpiece, and the holding portion and the workpiece are electrically connected by the first surface, whereby the workpiece is divided into a plurality of workpiece pieces. The machining current also flows through the holding portion during the dicing, and the exposed portion of the holding portion that is not in contact with the first surface is coated with an insulating coating .

According to the present invention, it is possible to provide a mechanism capable of preventing leakage of machining current from the surface of the workpiece exposed during electrical discharge machining with a wire.

The figure which shows the structure of the wire electric discharge machining system in this invention. FIG. 4 is a diagram showing changes in the relative positional relationship between the holding device and the machining tank from the start of electrical discharge machining to the end of electrical discharge machining in the present invention; The figure which showed the surface of the holding|maintenance part of the holding|maintenance apparatus in this invention. The figure which showed the cross section of the holding|maintenance part of the holding|maintenance apparatus in this invention. The figure which showed the back surface of the holding|maintenance part of the holding|maintenance apparatus in this invention. The figure which showed the surface of the insulating part of the holding|maintenance apparatus in this invention. The figure which showed the cross section of the insulating part of the holding|maintenance apparatus in this invention. The figure which showed the back surface of the insulating part of the holding|maintenance apparatus in this invention. The figure which showed the surface of the electricity supply part of the holding|maintenance apparatus in this invention. The figure which showed the cross section of the electricity supply part of the holding|maintenance apparatus in this invention. The figure which showed the back surface of the electricity supply part of the holding|maintenance apparatus in this invention. The figure which showed the surface of the base part of the holding|maintenance apparatus in this invention. The figure which showed the cross section of the base part of the holding|maintenance apparatus in this invention. The figure which showed the back surface of the base part of the holding|maintenance apparatus in this invention. The figure which showed the surface of the workpiece|work hold|maintained by the holding|maintenance apparatus in this invention. The figure which showed the cross section of the workpiece|work hold|maintained by the holding|maintenance apparatus in this invention. The figure which showed the back surface of the workpiece|work hold|maintained by the holding|maintenance apparatus in this invention. The figure which showed the surface of the holding|maintenance apparatus in the state which hold|maintained the workpiece|work in this invention. The figure which showed the cross section of the holding|maintenance apparatus in the state which hold|maintained the workpiece|work in this invention. The figure which showed the back surface of the holding|maintenance apparatus in the state which hold|maintained the workpiece|work in this invention. The figure which showed the vacuum piping connected with the holding|maintenance part of the holding|maintenance apparatus in this invention. FIG. 4 is a diagram showing changes in the relative positional relationship between a holding device and a wire before electrical discharge machining while holding a workpiece in the present invention; FIG. 4 is a diagram showing changes in the relative positional relationship between a holding device and a wire during electrical discharge machining while holding a workpiece in the present invention; FIG. 5 is a diagram showing changes in the relative positional relationship between the holding device and the wire when the electric discharge machining is completed while holding the workpiece in the present invention.

FIG. 1 will be explained.

FIG. 1 is an external view of a wire electric discharge machine 1 according to an embodiment of the present invention as seen from the front. The configuration of each mechanism shown in FIG. 1 is merely an example, and it goes without saying that there are various configuration examples depending on the purpose and application.

FIG. 1 shows the configuration of a wire electric discharge machining system (semiconductor substrate or solar cell substrate manufacturing system) according to the present invention. The wire electric discharge machining system is composed of a wire electric discharge machine 1 , a power supply device 2 and a machining liquid supply device 12 . A wire electric discharge machining system can slice a work piece into a plurality of work pieces at intervals between the side-by-side wire groups by electric discharge from the wire group to the work piece.

The wire electric discharge machine 1 is provided with a work feeding unit 3 driven by a servomotor above the wire group, and can move the work 106 in the vertical direction. In the present invention, the work 106 (shown in FIG. 2) is fed downward (gravity) by the work feeder 3, and electric discharge machining is performed between the work 106 and the wire group. In this specification, up and down correspond to upward and downward directions in the direction of gravity, respectively, and left and right correspond to left and right when the wire electric discharge machine is viewed from the front.

The power supply device 2 includes a servo control section 11 .

In order to efficiently generate electric discharge between the work 106 and the wire group (between the poles), the servo control unit 11 that controls the servo motor of the work feeding unit 3 sets the distance between the work 106 and the wire group in advance. The workpiece 106 being machined by electrical discharge is positioned while controlling to achieve the target voltage (first target voltage), and the electrical discharge machining of the workpiece 106 is advanced.

The power supply device 2 also includes a machining power supply control section.

The machining power supply control unit supplies machining power as an electric discharge pulse to the wire 103 during electric discharge machining. .

In addition, control is performed to adapt to a short-circuit state that suddenly occurs between the work 106 and the wire group (between electrodes) during electric discharge machining.

Also, the voltage between the workpiece 106 and the wire group (between electrodes) is used as a signal to the servo control unit 11 .

The machining fluid supply device 12 supplies the machining fluid necessary for cooling the electric discharge machining part and removing machining chips (waste) between the work 106 and the wire group (between electrodes) by a pump, and also supplies the machining chips in the machining fluid. is removed, conductivity (1 μS to 250 μS) is controlled by ion exchange, and liquid temperature (near 20° C.) is controlled. Water is mainly used, but electric discharge machining oil can also be used.

Grooves are formed in the main rollers 8 and 9 at a predetermined pitch and number so that the workpiece can be processed with a desired thickness. It is wound the required number of times and sent to the take-up bobbin. A wire speed of about 100 m/min to 900 m/min is used. By rotating the two main rollers in the same direction and at the same speed, one wire 103 sent from the wire feeding unit goes around the outer circumference of the main rollers (two), and is arranged side by side. It is possible to make the wire group running in the same direction (running means).

A wire 103 forming a group of wires arranged in parallel is a single connected wire, which is let out from a bobbin (not shown) and fitted into a guide groove (not shown) on the outer peripheral surface of the main roller while being fitted into the main roller. After being spirally wound many times (approximately 2000 times), it is wound on a bobbin (not shown).

The wire electric discharge machine 1 and the power supply device 2 are connected via a power cable 513, and the wire electric discharge machine 1 is operated by electric power supplied from the machining power supply controller.

The wire electric discharge machine 1 includes a work feeder 3 , a machining tank 6 , a main roller 8 , a wire 103 , a main roller 9 , a feeder unit 10 and a feeder 104 .

The work 106 is attached to the work feeding section 3 of the wire electric discharge machine 1 for slicing into a plurality of work pieces.

A wire 103 is wound a plurality of times around the main rollers 8 and 9, and the wire groups are aligned at a predetermined pitch according to the grooves cut into the main rollers. The main roller uses metal in the center and is covered with resin on the outside.

A power feeder 104 attached to the power feeder unit 10 is arranged between the two main rollers and above the central portion inside the main rollers 8 and 9. The power feeder 104 faces upward. A machining power supply is supplied to the traveling wire group by bringing the exposed surface thereof into contact with the wire group.

The surface of each feeder may be brought into collective contact with the wire group, and the machining power may be collectively fed to the running wire group,
The surface of each power feeder may be individually brought into contact with each wire of the wire group, and the machining power may be individually fed to each wire of the traveling wire group.

Further, the number of power supply terminals 104 is not limited to one, and a plurality of power supply terminals 104 may be used to supply machining power to the wire group.

Also, the number of machining voltages (Vmn) of the machining power supply 501 is not limited to one.

Needless to say, the number of feeders 104 and the number of machining voltages (Vmn) of the machining power supply 501 are appropriately increased according to the required number of wire groups.

The work feeding section 3 is a mechanism for vertically moving the work 106 connected to the work feeding section 3 by a holding device. By moving the work 106 downward, the work feeder 3 can bring the work 106 closer to the wire direction.

The machining tank 6 is a container for accumulating a machining fluid required for electric discharge generated between the workpiece 106 and the wire group. The working fluid is, for example, deionized water with a high resistance value. An electric discharge is generated between the wire group and the workpiece 106, and the workpiece can be sliced into a plurality of workpiece pieces at intervals of the wire group arranged side by side.

The main rollers 8 and 9 are formed with a plurality of rows of V-shaped grooves so as to hold the running wire 103 at predetermined intervals, and the wire 103 is wound around the grooves. Both of the main rollers 8 and 9 are rotated clockwise or counterclockwise to cause the wire group arranged side by side to run. Wire groups are formed in parallel above and below the main rollers 8 and 9 .

The wire 103 of the present invention is a conductor made of iron. is applied to wire 103 via .

A predetermined interval (pitch of V grooves) formed in the main rollers 8 and 9 is, for example, about 0.3 mm.

FIG. 2 will be explained.

FIG. 2 is a diagram showing changes in the relative positional relationship between the holding device and the machining tank 6 from the start of electric discharge machining to the end of electric discharge machining.

At the start of slicing in the figure, the relative positional relationship between the holding device and the machining tank 6 before the start of discharge corresponds to the state of FIG. 10-1.

At the start of slicing, the holding device holds the workpiece 106, but is not immersed in the working fluid.

After that, the holding device approaches the wire while holding the work 106 by the work feeder 3 . After that, when the inter-electrode distance between the wire 103 and the work 106 becomes narrow, an electric discharge is generated from the wire 103 toward the work 106 , and a machining current also starts to flow through the work 106 due to the electric discharge. The machining current flowing through the workpiece 106 flows from the energizing section to the machining power supply section. It may become stable. Therefore, in the present invention, the surface of the workpiece 106 is covered with a plate of insulating plastic or the like so as to suppress or prevent leakage current flowing toward the machining fluid, thereby solving the instability of electric discharge machining. .

The end of slicing in the figure shows the relative arrangement relationship between the holding device and the processing tank 6 at the end of processing, and corresponds to the state of FIG. 10-3.

At the end of slicing, the holding device holds a plurality of sliced work pieces 107 (shown in FIG. 2) and is immersed in the working fluid.

Before the start of machining, the conducting part 814 is electrically connected to the work 106 as shown in FIG.

Since the conducting portion 814 is electrically connected to the work 106 after starting machining as shown in FIG.

After finishing machining, the conducting part 814 is electrically connected to all the work pieces 107 whose slicing is completed as shown in FIG. 10-3. can flow. After the work pieces 107 are all sliced in this way, electrical discharge machining proceeds to the current-carrying portion 814 .

FIG. 3 will be explained.

FIG. 3-1 is a diagram showing the surface of the holding portion 811 of the holding device.

Each function provided in the holding portion 811 will be described.

The shape of the holding portion 811 is not limited to the shape of the plate shown in the embodiment, and may be any shape as long as it covers the first surface of the work 106 and is wider than the area of the first surface of the work 106. may

Also, the workpiece 106 can be held by suction by the vacuum groove 2000 .

FIG. 3-1 is a view of the holding part 811 seen from the side of the chucking surface that chucks the workpiece 106. FIG.

By using the vacuum grooves 2000 to suck the holding surface (first surface) of the workpiece 106 which is not subjected to electrical discharge machining, the workpiece 106 can be held during the electrical discharge machining. By sucking and holding at this position, the holding part 811 does not physically interfere with the wire 103 during electrical discharge machining as shown in FIGS. can be held so as not to fall vertically.

Since the holding portion 811 is not on the route that contacts the wire 103 during electric discharge machining, the wire 103 does not carry out the electric discharge machining of the holding portion 811 .

The screw hole is a hole for attaching the holding part 811 to the base 815 (shown in FIG. 6-1) using a fixing member such as a screw or a screw. There are two screw holes, and the holding part 811 can be attached to the base 815 .

In the first embodiment of the present invention, it is desirable to use a conductive material (conductive material) for the holding portion 811, such as aluminum or SUS. If a conductive material is used, the machining current will also flow through the holding portion 811 .

Furthermore, in the second embodiment of the present invention, when the holding part 811 is intended only for the holding function, the shape and structure of the holding part 811 maintains the mechanism of suction as in the first embodiment, and the material is glass, semiconductor, plastic, or the like. Non-conductive materials such as rubber may also be used. However, if a non-conductive material is used, the machining current will not flow through the holding portion 811 .

FIG. 3-2 is a cross-sectional view of the holding portion 811 of the holding device. The work 106 can be held by suction by the vacuum grooves 2000 .

FIG. 3-3 is a diagram showing the back surface of the holding portion 811 of the holding device.

This back surface is the surface that is exposed to the working fluid when the holding device is immersed in the working fluid. As in the previous explanation, a leak current flows from the back surface to the machining liquid, and electric discharge machining may become unstable. Therefore, in the present invention, the instability of electric discharge machining is solved by coating the back surface of the holding portion 811 with an insulating coating agent or the like so as to suppress or prevent leakage current flowing toward the machining fluid. there is The instability of electric discharge machining can also be solved by attaching an acrylic plate made of an insulating material similar to that of the insulating portion 812 or a plate made of plastic or the like with an adhesive or the like to the back surface of the holding portion 811 . can be done.

The screw hole is a hole for attaching the holding part 811 to the base 815 (shown in FIG. 6-1) using a fixing member such as a screw or a screw. There are two screw holes, and the holding part 811 can be attached to the base 815 .

FIG. 4 will be explained.

FIG. 4-1 is a diagram showing the surface of the insulating portion 812 of the holding device.

Each function provided in the insulating portion 812 will be described.

The shape of the insulating portion 812 is not limited to the plate shape shown in the embodiment, and it is desirable to cover the entire second surface of the work 106. It should be wider than 90%. (It is desirable that 90% or more is covered with the insulating portion 812.) Any shape is acceptable.

FIG. 4-1 is a view of the insulating portion 812 viewed from the contact surface side in contact with the second surface of the workpiece 106. FIG.

By bonding the interface between this contact surface and the insulating surface (second surface) of the workpiece 106 which is not subjected to electrical discharge machining with a non-conductive adhesive, the insulating surface (second surface) of the workpiece 106 is maintained throughout the electrical discharge machining. surface) can be insulated. By bonding the insulating portion 812 at this position, the insulating portion 812 does not interfere with the wire 103 during electric discharge machining as shown in FIGS. be able to.

Since the insulating portion 812 is not on the route that contacts the wire 103 during electrical discharge machining, the wire 103 does not perform electrical discharge machining on the holding portion 811 .

FIG. 4-2 is a cross-sectional view of the insulating portion 812 of the holding device.

FIG. 4-3 is a view showing the back surface of the insulating portion 812 of the holding device.

This back surface is the surface that is exposed to the working fluid when the holding device is immersed in the working fluid.

FIG. 5 will be explained.

FIG. 5-1 is a diagram showing the surface of the conducting portion 814 of the holding device.

The functions provided in the conducting portion 814 will be described.

The shape of the conducting portion 814 is desirably the rectangular parallelepiped shape shown in the embodiment. By making surface contact with the orientation flat surface of the work 106 , it is possible to conduct electricity in a wide range between the orientation flat surface of the work 106 and the conducting portion 814 .

The role of the energizing portion 814 is to continuously energize the work 106 during electric discharge machining, and in order to increase the contact area with the work 106, it has a rectangular parallelepiped shape. The upper surface of the portion 814 is adhered to the base 815 using a conductive adhesive so as to be electrically conductive, and the base portion 815 is also electrically connected to the work feeding unit 3 .

As shown in FIG. 10-1, the lower surface of the current-carrying portion 814 is adhered to the orientation flat surface using a conductive adhesive so as to be electrically conductive.

FIG. 5-2 is a cross-sectional view of the current-carrying portion 814 of the holding device.

FIG. 5-3 is a diagram showing the back surface of the current-carrying portion 814 of the holding device.

The current-carrying portion 814 can be made of a material such as aluminum, which is a conductive material. However, since the current-carrying portion 814 is mainly intended for the current-carrying function, it may be made of other conductive materials. .

By bonding the orientation flat surface where the work 106 is cut into a plurality of work pieces with a conductive adhesive, as shown in FIGS. can be energized without physically interfering with the workpiece 106 at all, and the machining current can be supplied to the workpiece 106 all the time while the workpiece 106 is being cut into a plurality of workpiece pieces 107 .

Since the current-carrying part 814 is not on a route that interferes with the wire 103 during electric discharge machining, the current-carrying part 814 is not machined until just before the wire 103 completely cuts the workpiece into a plurality of work pieces.

FIG. 6 will be explained.

FIG. 6-1 is a diagram showing the surface of the base portion 815 of the holding device.

Each function provided in the base portion 815 will be described.

The main role of the base portion 815 is to serve as a base for attaching the entire holding device including the current-carrying portion 814, the holding portion 811, the work 106, and the insulating portion 812 to the work feeding portion 3 during electrical discharge machining. In addition, the base portion 815 is provided with two screw holes for attachment to the work feeding portion 3 .

The base portion 815 can be made of a conductive material such as aluminum or SUS. may be configured.

FIG. 6-2 is a cross-sectional view of the base portion 815 of the holding device.

FIG. 6-3 is a view showing the underside of the base portion 815 of the holding device.

The base portion 815 is provided with two screw holes for attaching the holding portion 811 to the base portion 815 .

The screw hole is a hole for attaching the holding portion 811 to the base 815 using a fixing member such as a screw or a screw. There are two screw holes, and the holding part 811 can be attached to the base 815 .

FIG. 7 will be explained.

FIG. 7-1 shows the surface of the workpiece held by the holding device.

In the example, the workpiece 106 has a cylindrical shape. In the case of a cylindrical work 106, the holding part 811 holds the work 106 on a flat surface on which the work 106 is not subjected to electric discharge machining, and the energizing part 814 energizes the work 106 on the orientation flat surface of the work 106. FIG. The cylindrical peripheral surface of the workpiece 106 is subjected to electrical discharge machining.

The shape of the work 106 held by the holding device 800 may be rectangular parallelepiped (angular).

FIG. 7-2 is a view showing a side surface (peripheral surface of a cylinder) of a work held by a holding device.

FIG. 7-3 is a diagram showing the back surface of the work held by the holding device.

FIG. 8 will be explained.

FIG. 8-1 is a diagram showing the surface of the holding device holding the workpiece. It shows a state in which a cylindrical workpiece 106 is attached to the holding device. The conducting portion 814 and the base portion 815 are adhered with a conductive adhesive. The conducting portion 814 and the workpiece 106 are adhered with a conductive adhesive. The base portion 815 is attached to the work feeding portion with two screws.

An insulating portion 812 is attached to the surface (second surface) of the work 106 with a non-conductive adhesive, double-sided tape, or the like.

FIG. 8-2 is a side view of the holding device holding the workpiece. At this time, the side surface of the work (circular cylindrical surface) is visible. It shows a state in which a cylindrical workpiece 106 is attached to the holding device.

On the back surface (first surface) of the work 106, the holding part 811 sucks the work 106 with a vacuum. The holding portion 811 is attached to the base portion 815 with screws.

Thus, during electric discharge machining, if the holding portion 811 is made of a conductive material, a machining current also flows through the holding portion 811 .

FIG. 8-3 is a view showing the back surface of the holding device holding the workpiece. It shows a state in which a cylindrical workpiece 106 is attached to the holding device.

On the surface (first surface) of the work 106, the holding part 811 sucks the work 106 with a vacuum. The holding portion 811 is attached to the base portion 815 with screws.

FIG. 9 will be explained.

FIG. 9 is a diagram showing the back surface of the holding device holding the work.

A vacuum is supplied to the holding portion 811 through the vacuum pipe 2003 .

The holding device and the vacuum pipe 2003 are connected at a vacuum connection (not shown).

The supplied vacuum is connected to the vacuum groove 2000 inside the holding portion 811, and the work 106 can be vacuumed by the holding portion 811 on the surface (first surface) of the work 106. FIG. 10 will be described. .

FIG. 10-1 is a diagram showing the transition of the relative positional relationship between the holding device and the wire before electric discharge machining while holding the work. ing.

Also, since the wire 103 and the work 106 are sufficiently separated, no electric discharge is generated from the wire 103 to the work 106 . Although the machining tank 6 is filled with the machining fluid, the holding device is not immersed in the machining fluid. After that, the holding device brings the work 106 closer to the wire 103 by lowering the work feeding unit 3, and electric discharge from the wire 103 to the work 106 starts. This corresponds to the state at the start of slicing in FIG.

Fig. 10-2 is a diagram showing the transition of the relative positional relationship between the holding device and the wire during electric discharge machining while holding the work. ing.

Also, the wire 103 and the workpiece 106 are in a state in which electric discharge is generated at the optimum inter-electrode distance. Wire 103 has begun slicing a portion of workpiece 106 . At this time, the machining current that flows through the work 106 after being discharged to the work 106 flows through the work 106 via the current-carrying portion 814, and also passes through the holding portion 811 near the wire 103 to the work 106. will flow through.
If the workpiece 106 is made of a material with an unstable composition such as SiC, it is difficult for the machining current to flow through the workpiece 106 .
Therefore, not only the machining current is passed through the work 106 via the current-carrying part 814, but also the work 106 is passed through the holding part 811 which is present in the vicinity of the discharge point and has a uniform material component to perform electric discharge machining. Advancement has the effect of making electric discharge machining more stable.
Thus, the machining current flows through both the conducting portion 814 and the holding portion 811 until just before the work 106 is completely cut into the plurality of work pieces 107 .

Furthermore, since the surface (exposed portion) of the holding portion 811 exposed to the machining fluid is surface-coated with an insulating material, the current flows to the conducting portion 814 through the holding portion 811 near the wire 103 . However, the problem of machining current leakage from the surface (exposed portion) can be resolved.

FIG. 10-3 is a diagram showing the transition of the relative positional relationship between the holding device and the wire when the electric discharge machining is completed while holding the work. I see

In the case of this figure, when all the plurality of work pieces 107 are cut, there are three work pieces (left, middle and right).

Since the current-carrying portion 814 is provided at the end of cutting in this way, even when all the plurality of work pieces 107 have been cut, the current-carrying portion 814 can appropriately energize the middle work piece 107 as well. Furthermore, the middle work piece 107 is thin and light, so it can be held with only a conductive adhesive.

Further, the left work piece 107 is thin and light and can be held with only a conductive adhesive.

Furthermore, the work piece 107 on the right side is thin and light and can be held by the holding portion 811 .

The current-carrying portion 814 is provided at the end of cutting, and by performing electric discharge machining on a part of the current-carrying portion 814 , the plurality of work pieces 107 can be successfully cut.
When the workpiece 106 is completely cut into the plurality of workpiece pieces 107 in this manner, the machining current flows only through the current-carrying portion 814 .

When the control of the holding unit 811 vacuum-sucking the workpiece 106 is turned on and the control of not vacuum-sucking is turned off, the wafer piece 107 sucked by the holding unit 811 can be removed by switching from ON to OFF. It can be easily separated from the holding portion 811 .

Reference Signs List 1 wire electric discharge machine 2 power supply 3 work feeder 5 base 6 machining tank 8 main roller 9 main roller 12 machining liquid supply device 103 wire 104 feeder 106 work 107 a plurality of work pieces 811 holding section 812 insulating section 814 conducting section 815 Base portion 2000 Vacuum groove 2003 Vacuum piping

Claims (5)

A holding device for use in wire electric discharge machining for holding a workpiece while cutting it into a plurality of workpiece pieces,
a current-carrying portion made of a conductive material;
a holding portion made of a conductive material that holds the work while cutting the work into a plurality of work pieces;
an insulating portion made of an insulating material;
with
A machining current is passed through the work while the work is cut into a plurality of work pieces by electrically connecting the current-carrying part and the work at a point where the work is finished being cut into a plurality of work pieces,
holding the work using the holding part on the first surface of the work;
The second surface is covered with the insulating portion capable of preventing leakage of the machining current from the second surface, which is the back side of the first surface, and
By electrically connecting the holding portion and the work on the first surface, the machining current also flows through the holding portion while the work is cut into a plurality of work pieces,
A holding device , wherein an exposed portion of the holding portion that is not in contact with the first surface is coated with an insulating coating . The machining current flows through both the energizing portion and the holding portion until just before the workpiece is completely cut into a plurality of work pieces. 2. Holding device according to claim 1 , characterized in that a machining current flows. A machining current is passed through the work while the work is cut into a plurality of work pieces by bonding an interface between the current-carrying part and the work with a conductive adhesive at a point where the work is finished being cut into a plurality of work pieces. 3. A holding device according to claim 1 or 2 , characterized in that: The holding device according to any one of claims 1 to 3 , wherein the insulating portion is adhered to the second surface. The holding device according to any one of claims 1 to 4 , wherein the holding device is immersed in a working liquid while the work is being cut into a plurality of work pieces.

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