JP2000015552A - Cutting method and device of wire saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting method and device of wire saw which can suppress the generation of a saw mark. SOLUTION: A control device 32 applies a voltage to a piezoelectric element 88, and displaces an ingot 26 at a specific amount, when the running direction of wires with fixed abrasive grains 14 is converted. This displacement amount is set same as the displacement amount of the wires with fixed abrasive grains 14 when their running direction is converted. As a result, the positioning relation between the wires with fixed abrasive grains 14 and the ingot 26 is made the same constantly, and the generation of a saw mark is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cutting a wire saw, and more particularly to a method and an apparatus for cutting a hard and brittle material such as silicon, glass and ceramic.

[0002]

2. Description of the Related Art A wire saw is one of devices for cutting a wafer from an ingot of a hard brittle material such as silicon.
This wire saw is roughly classified into two types: fixed abrasive wire saws and loose abrasive wire saws. Fixed abrasive wire saws
A fixed abrasive grain (diamond abrasive grain, ceramic abrasive grains such as SiC, CBN, etc.) is fixed to the peripheral surface of a wire (piano wire, stainless steel wire, etc.) to form a wire row with fixed abrasive grains. While running, the ingot is pressed against the wire row while supplying the coolant liquid to the wire row from the nozzle, and the ingot is cut into many wafers. On the other hand, loose-abrasive wire saws do not have abrasive grains fixed to the wire, and cut the ingot into multiple wafers by spraying a machining fluid with suspended abrasive grains onto the wire rows and attaching the abrasive grains to the wires. I do.

[0003]

However, a pattern called a saw mark may be formed on a cut surface of a wafer cut with a conventional wire saw. A possible cause of the saw mark is that the wire slides in the axial direction of the workpiece by running the wire in a twisted state. The generated saw mark needs to be scraped off in a later step. Therefore, the conventional wire saw has disadvantages in that the loss of the step and the material is increased and the cost is increased.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method and an apparatus for cutting a wire saw capable of suppressing the occurrence of saw marks.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a wire train formed by winding a wire around a plurality of grooved rollers, running the wire and cutting the wire train. In a wire saw cutting method for simultaneously cutting a large number of wafers by pressing a columnar workpiece against a portion, the traveling direction of the wire is alternately switched, and the workpiece is attached to the workpiece at the time of the switching. The workpiece is moved by a predetermined amount in the axial direction.

In order to achieve the above object, according to the present invention, a wire is wound around a plurality of grooved rollers to form a wire array, the wire is run, and a columnar covering is formed on a cut portion of the wire array. In a wire saw cutting device for simultaneously cutting a large number of wafers by pressing a workpiece, a moving means for moving the workpiece along an axial direction of the workpiece and a traveling direction of the wire are switched. Switching means, and control means for controlling the moving means so that the workpiece moves a predetermined amount in the axial direction of the workpiece when the switching means switches the traveling direction of the wire. It is characterized by being.

According to the present invention, when switching the traveling direction of the wire, the workpiece is moved by a predetermined amount along the axial direction. This can prevent the relative position between the laterally slid wire and the workpiece from shifting, thereby suppressing the occurrence of saw marks.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wire saw cutting device according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing an entire configuration of a fixed abrasive wire saw to which the present invention is applied, and FIGS. 2 and 3 are a front view and a side view of an ingot moving unit 63.

As shown in FIG. 1, a fixed abrasive wire saw 1
No. 0 has a pair of wire reels 12A and 12B, and one of the wire reels 12A is wound with a wire 14 with fixed abrasive grains having abrasive grains fixed to the peripheral surface. Wire 14 with fixed abrasive grains wound on wire reel 12A
Are driven through a wire traveling path formed by a number of guide rollers 20, 20,.
2 to form a horizontal row of wires 24. The wire 14 with the fixed abrasive grains having the wire row 24 formed thereon is wound on a wire reel 12B via a wire running path on the other side formed symmetrically with respect to the wire row 24.

[0010] The pair of wire reels 12A, 12B
Are fixed on turntables 16A and 16B, and reel drive motors 18A and 18B are connected to the turntables 16A and 16B. The reel drive motors 18A and 18B are configured to be rotatable forward and backward,
By driving the reel driving motors 18A and 18B, the wire 14 with the fixed abrasive is
The vehicle travels back and forth between A and 12B at high speed.

A work feed table 72 is provided above the wire row 24 so as to move vertically with respect to the wire row 24. The ingot 26 to be processed is mounted on the work feed table 72 via the tilting unit 80 and the ingot moving unit 63. An unillustrated elevating means is connected to the work feed table 72, and the ingot 26 is moved up and down with respect to the wire row 24 by elevating the work feed table 72.

Below the tip of the work feed table 72, a tilting unit 80 is provided, and further below the tilting unit 80, an ingot moving unit 6 is provided.
3 is supported. Then, the ingot 26 is attached to the slide member 65 which is a component of the ingot moving unit 63 via the mounting block 28 and the slice base 30. That is, the ingot 26 is bonded to the slice base 30, and the slice base 30 is bonded to the mounting block 28.

Next, the ingot moving unit 63 for moving the ingot 26 will be described. The ingot moving unit 63 mainly includes a support member 82, a slide member 86, a piezoelectric element 88, and the control device 32.
The support member 82 is formed in an L shape, and is fixed to a lower side of the tilting unit 80. The slide member 86 is slidably attached to the support member 82. That is,
A pair of guide rails 90, 90 are disposed on the upper surface of the slide member 86 along the axial direction of the ingot 26, and linear bearings 84, 84, which respectively engage with the pair of guide rails 90, are provided. , Are provided on the lower surface of the horizontal plate 82B of the support member 82. Thus, the slide member 86 is suspended from the support member 82 via the guide rail 90 and the linear bearing 84 so as to be slidable in the axial direction of the ingot 26.

Further, the slide member 86 includes an upper plate 86
A, a back plate portion 86B and both side plate portions 86C, 86C are formed in a hollow rectangular shape in which the front surface portion 86D and the bottom plate portion 86E are open. The both side plate portions 86C, 86C of the slide member 86 are formed in a state facing the L-shape.
A horizontal reference surface is formed on the upper surface of the L-shaped horizontal portions 86F, and a vertical reference surface is formed on the inner surface 86G of the back plate portion 86B. Then, the mounting block 28
Is inserted into the slide member 86 from the open front surface portion 86D of the slide member 86 to mount the mounting block 28.
The horizontal reference plane and the vertical reference plane formed on the
6 is brought into contact with the horizontal reference plane and the vertical reference plane. As a result, the mounting block 28 is
When the slide member 86 is slid, the ingot 26 also moves accurately in the axial direction.

The upper plate 86A of the slide member 86 is provided with clamp cylinders 92, 92. The rods 92A, 92A extend and press the upper surface of the mounting block 28. This allows
The mounting block 28 mounted on the slide member 86 can be fixed in a correctly positioned state.

The piezoelectric element 88 is mounted so that its operation direction coincides with the axial direction of the ingot 26. Thereby, when the piezoelectric element 88 is operated, the ingot 26
Slides in the axial direction via the slide member 86.
The piezoelectric element 88 is connected to the control device 32 via a signal cable, and operates when a voltage is applied by the control device 32.

The control device 32 includes a motor 18 for driving the reel.
A, 18B connected via a signal cable, when the reel drive motors 18A, 18B switch their rotation direction and the traveling speed of the fixed abrasive wire 14 becomes zero,
The piezoelectric element 88 is configured to apply a predetermined voltage. Fixed abrasive wire saw 10 configured as above
Is as follows.

First, the ingot 26 is mounted on the work feed table 72. Next, the reel driving motor 1
8A and 18B are driven to rotate the wire reels 12A and 12B synchronously, and the wire 14 with fixed abrasive grains is reciprocated at high speed. Then, the work feed table 72 is lowered toward the wire row 24, and the ingot 26 is pressed against the traveling wire row 24. The ingot 26 pressed against the wire row 24 is ground at the contact portion with the wire row 24 into the wire 14 with the fixed abrasive, and thereby cut into a wafer.

In the above process, the control device 3
2 displaces the ingot 26 in accordance with the amount of displacement of the wire 14 with the fixed abrasive when the traveling speed of the wire 14 with the fixed abrasive becomes zero. Hereinafter, the control method will be described. FIGS. 4A and 4B are explanatory diagrams for explaining a running state of the wire 14 with fixed abrasive grains. FIG. 4A shows a state in which the wire 14 with fixed abrasive grains is stopped, and FIGS.
(C) has shown the state where the wire 14 with a fixed abrasive was run in the opposite direction, respectively.

The wire row 24 is formed by a groove roller 22
Are formed by winding the wire 14 with fixed abrasive grains around a number of V-shaped grooves 34, 34,. The wire 14 with fixed abrasive grains is generally wound in a twisted state, and travels in that state when fed in one direction. Then, when traveling while being twisted as indicated by an arrow 36 in FIG. 4B, the wire 14 with the fixed abrasive rises along the slope 34A and travels in that state. As a result, the wire 14 with the fixed abrasive grains is formed as shown in FIG.
In comparison with the position of the ingot 26, the ingot 26 slides in the axial direction by L1.

When the traveling direction of the wire 14 with the fixed abrasive is reversed, the twisting direction is reversed as shown in FIG. 4C, and the wire 14 travels while being twisted in the direction of the arrow 38. For this reason, the fixed abrasive wire 14 rises along the inclined surface 34B and travels in that state. Thereby, the wire 14 with fixed abrasive grains slides by L2 in the axial direction of the ingot 26 as compared with the position of FIG. In this way, the fixed abrasive wire 14 is displaced by L1 + L2 by switching the running direction. The amount of displacement, L1 + L2, is determined by cutting the ingot 32 into a test wafer without moving it in the axial direction and measuring the amount of unevenness on the cut surface of the wafer with a roughness meter.

The amount of displacement and the direction of displacement are input to the controller 32 in advance, and the ingot 26 is moved so as to cancel the displacement of the wire 14 with the fixed abrasive. That is, the control device 32 applies a predetermined voltage to the piezoelectric element 88 when the reel driving motors 18A and 18B switch the rotation direction and the traveling speed of the fixed abrasive wire 14 becomes zero,
The ingot 26 is moved in the displacement direction of the wire 14 with the fixed abrasive grains by the displacement amount.

FIG. 5 shows changes over time in the displacement of the ingot and the traveling speed of the wire with fixed abrasive grains when the fixed abrasive wire saw is controlled as described above. Here, the α period in FIG.
4 (b), and the β period in FIG. 5 corresponds to FIG. 4 (c). As described above, the control device 32 controls the piezoelectric element 8 when the traveling speed of the fixed abrasive wire 14 becomes zero.
8, a predetermined voltage is applied to displace the ingot 26. As a result, as shown in FIG. 5, the ingot 26 during the α period is displaced L1 to the right, and the ingot 26 during the β period is displaced L2 to the left.

The wire 14 with the fixed abrasive grains is displaced in the axial direction of the ingot 26 and travels in a twisted state as described above. For example, the wire 14 with the fixed abrasive in the α period travels in a state of being displaced L1 to the right as shown in FIG. 4B, and the wire 14 with the fixed abrasive in the β period is shown in FIG. L to the left as shown in
The vehicle travels with two displacements.

Therefore, when the above-described displacement is applied to the ingot 26, the displacement amount of the ingot 26 and the wire 14 with the fixed abrasive becomes equal, and the fixed abrasive 14 is always positioned at the cutting reference position of the ingot 26. be able to. As described above, in the fixed-abrasive wire saw of the present embodiment, since the fixed-abrasive wire 14 can always be moved to the cutting reference position of the ingot 26 and run, a saw mark is generated on the cut surface of the cut wafer. Can be suppressed.

In the embodiment described above, when the traveling direction of the wire 14 with the fixed abrasive is switched, the ingot 2
Although 6 has been displaced by a predetermined amount, it may be displaced so as to correspond exactly to the uneven surface obtained by cutting the wafer on a trial basis.
Further, the control device 32 is not limited to the above-described embodiment, and when the traveling direction of the wire 14 with fixed abrasive is switched, the positional relationship between the wire 14 with fixed abrasive and the ingot 32 is kept constant. Anything that moves the ingot 32 so as to keep it may be used.

Further, the above embodiment has been described with reference to the example of the fixed abrasive wire saw, but a free abrasive wire saw may be used.

[0028]

As described above, according to the wire saw cutting method and apparatus of the present invention, it is possible to suppress the occurrence of saw marks on the cut surface of the cut wafer, thereby reducing the process and material loss. be able to.

[Brief description of the drawings]

FIG. 1 is a front view illustrating the entire configuration of a fixed abrasive wire saw using the present invention.

FIG. 2 is a front view of the ingot moving unit of FIG. 1;

FIG. 3 is a side view of the ingot moving unit of FIG. 1;

FIG. 4 is an explanatory view of a running state of a wire with fixed abrasive grains.

FIG. 5 is a diagram illustrating the operation of a fixed abrasive wire saw using the present invention.

[Explanation of symbols]

 12A, 12B: Wire reel 14: Wire with fixed abrasive 18A, 18B: Reel driving motor 20: Guide roller 22: Groove roller 24: Wire row 26: Ingot 32 ... Control device 63: Ingot moving unit 72: Work feed table 82 Support member 84 Linear bearing 86 Slide member 88 Piezoelectric element 90 Guide rail 92 Clamp cylinder

Claims (2)

[Claims] A wire is wound around a plurality of grooved rollers to form a wire array, and the wire is run, and a columnar workpiece is pressed against a cut portion of the wire array to form a large number of wires. In a wire saw cutting method for simultaneously cutting a wafer, the running direction of the wire is alternately switched, and at the time of the switching, the workpiece is moved by a predetermined amount in the axial direction of the workpiece. Cutting method. 2. A plurality of grooves are formed by winding a wire around a plurality of grooved rollers, and by moving the wire and pressing a columnar workpiece against a cut portion of the wire row. In a wire saw cutting apparatus for simultaneously cutting a wafer, a moving unit for moving the workpiece along an axial direction of the workpiece, a switching unit for switching a traveling direction of the wire, And a control means for controlling the moving means so that the workpiece moves a predetermined amount in the axial direction of the workpiece when switching the traveling direction.