JP2016074049A - Wire saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the breakage of wire by making a current for electric discharge machining uniformly pass through the wire, in a wire saw.SOLUTION: A wire saw 20 includes at least holding means 10 for holding an ingot 50, and a wire 31 which performs electric discharge machining on the ingot 50 held by the holding means 10 to slice it. The holding means 10 is composed of at least an energizing portion 13 contacted with an outer periphery of the ingot 50 and connected to a positive pole of a power source 35, and a fixing portion 14 fixing the ingot 50. The energizing portion 13 is connected to the ingot 50 through a carbon double-sided tape 16. The energizing portion 13 is connected to the ingot 50 through the carbon double-sided tape 16, so that a current uniformly passes through the wire 31 due to the uniform conductivity of the carbon double-sided tape 16. Consequently, the breakage of the wire 31 can be prevented.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a wire saw that slices an ingot by electric discharge machining.

  Silicon carbide (SiC: silicon carbide) has intermediate properties between diamond and silicon and is excellent in hardness, heat resistance and chemical stability, so it is used for abrasives, refractories, heating elements, etc. Since it is also a semiconductor, it is also used as a material for electronic devices such as power devices.

  In order to produce an electronic device made of SiC, it is necessary to cut a SiC ingot to form a wafer having a predetermined thickness. Usually, a wire saw is used for cutting out from an SiC ingot.

  The wire saw includes at least a holding unit that is connected to one electrode of the power source and holds the ingot, and a wire that performs electric discharge machining on the ingot connected to the other electrode of the power source and held by the holding unit and slices the wafer into a wafer shape. And the SiC ingot is fixed to the holding means with a conductive carbon adhesive. And the SiC ingot which has the hardness next to a diamond can be sliced into the wafer of predetermined thickness by electric discharge machining (for example, refer to patent documents 1).

JP 2000-84221 A

  However, since the carbon adhesive has fluidity, the carbon mixed in the bond agent may be dispersed in a portion where the density of the carbon is high and a portion where the carbon density is low, and the current may not flow uniformly in the ingot. There is a problem that a strong electric discharge is intermittently generated in the wire and the wire is disconnected.

  The present invention has been considered in view of such a problem, and in a wire saw, a current for electric discharge machining is made to uniformly flow through the wire.

  The present invention is a wire saw including at least a holding means for holding an ingot, and a wire for slicing an ingot held by the holding means by electric discharge machining, the holding means being in contact with the outer periphery of the ingot and supplying power. It is comprised at least from the electricity supply part connected to a positive electrode, and the fixing | fixed part which fixes an ingot, and an electricity supply part is connected to an ingot via a carbon double-sided tape.

  In the above-described wire saw, the energization unit includes a first energization unit and a second energization unit that are disposed with an interval, and the fixing unit is between the first energization unit and the second energization unit. It is preferable to arrange | position in.

  In the wire saw according to the present invention, since the current-carrying portion constituting the holding means is connected to the ingot via the carbon double-sided tape, a uniform current flows through the wire due to the uniform conductivity of the carbon double-sided tape, so a strong discharge This can prevent the wire from being disconnected.

  Further, the fixed portion is disposed between the first energization portion and the second energization portion that are disposed with a space therebetween, whereby the electrodes and ingots by the first energization portion and the second energization portion. The ingot can be surely fixed while energizing with.

It is a perspective view which shows the example of the holding means which comprises a wire saw. It is a perspective view which shows a holding means and an ingot. It is a perspective view which shows a wire saw and an ingot. It is a perspective view which shows the state which discharge-processes an ingot with a wire saw.

  The holding means 10 shown in FIG. 1 holds an ingot that is cut by a wire in a wire saw, and is fixed on the base 11, an elevator 12 that can be raised and lowered relative to the base 11, and the elevator 12. The energizing part 13 and the fixing part 14 for fixing the ingot are provided.

  The energizing part 13 is formed of a conductive member in a substantially U-shaped cross section, and has a first energizing part 131a and a second energizing part 131b that protrude upward. The 1st electricity supply part 131a and the 2nd electricity supply part 131b are arrange | positioned at intervals.

  The upper surface 132a of the first energization part 131a and the upper surface 132b of the second energization part 131b are formed in a shape that follows the shape of the outer peripheral surface of the ingot. The fixing portion 14 is disposed between the first energization portion 131a and the second energization portion 131b.

  As shown in FIG. 2, the fixing portion 14 is filled with a bonding agent 15 made of an epoxy resin or the like. On the other hand, the carbon double-sided tape 16 having conductivity is attached to the upper surface 132a of the first energizing part 131a and the upper surface 132a of the second energizing part 131b. The ingot 50 is placed on the carbon double-sided tape 16, and the outer periphery of the ingot 50 is in contact with the carbon double-sided tape 16, whereby the ingot 50 is connected to the energizing portion 13. As the carbon double-sided tape 16, for example, a carbon double-sided tape for SEM provided by Nissin EM Co., Ltd. can be used.

  The wire saw 20 shown in FIG. 3 includes the holding means 10 shown in FIGS. 1 and 2, a plurality of wires 31 parallel to each other, two rotatable guide rollers 32 and 33 that guide the wires 31, and the wires 31. And a power source 35 connected between the rotary electrode 34 and the energization unit 13.

  The guide rollers 32 and 33 are formed with the same number of guide grooves 321 and 331 as the number of wires 31, respectively, and the wire 31 is engaged with the guide grooves 321 and 331. The wire 31 is positioned above the energization unit 13 in a state where tension is applied.

  The wire 31 is sliced by performing electric discharge machining by contacting the ingot 50 held by the holding means 10. Further, the positive electrode of the power source 35 is connected to the energization unit 13, and the negative electrode of the power source 35 is connected to the rotary electrode 34.

  In the case of slicing an ingot in the wire saw 20 configured as described above, the lifting platform 12 is raised in a state where the ingot 50 is adhered to the carbon double-sided tape 16 and fixed to the fixing portion 14 by the bond agent 15. Go. Then, the wire 31 comes into contact with the ingot 50, and the elevator 12 is further lifted, and the wire 31 is fed into the extending direction of the wire 31 by the guide rollers 32 and 33, so that the wire 31 is cut into the ingot 50. EDM is performed while going on.

  When the elevator 12 is further raised, the current-carrying portion 13 is also subjected to electric discharge machining, the ingot 50 is completely sliced, and a plate-shaped wafer is cut out.

  Since the ingot 50 is fixed to the energizing portion 13 through the carbon tape both surfaces 16 having no fluidity, a current flows uniformly through the ingot 50. Therefore, strong discharge does not occur in the wire 31, and the risk of disconnection in the wire 31 can be reduced.

  Moreover, since the fixing | fixed part 14 is arrange | positioned between the 1st electricity supply part 131a and the 2nd electricity supply part 131b which are arrange | positioned at intervals, the 1st electricity supply part 131a and the 2nd electricity supply part The ingot 50 can be reliably fixed while energization of the electrode 35 and the ingot 50 by the part 131b is ensured.

10: holding means 11: base 12: lifting platform 13: energizing part 131a: first energizing part 131b: second energizing parts 132a, 132b: upper surface 14: fixing part 15: bonding agent 16: carbon double-sided tape 20: Wire saw 31: Wire 32, 33: Guide roller 321, 331: Guide groove 34: Rotary electrode 35: Power supply 50: Ingot

Claims (2)

A wire saw comprising at least holding means for holding an ingot, and a wire for slicing by applying electric discharge machining to the ingot held by the holding means,
The holding means is composed of at least an energizing portion that contacts the outer periphery of the ingot and is connected to the positive electrode of the power source, and a fixing portion that fixes the ingot.
The energizing part is a wire saw connected to an ingot via a carbon double-sided tape. The energization unit includes a first energization unit and a second energization unit arranged with a space therebetween, and the fixing unit is interposed between the first energization unit and the second energization unit. The wire saw according to claim 1, which is arranged.

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