JP3244099B2 - Wire abrasion detector for wire saws - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the amount of wire wear of a wire saw, and more particularly to cutting a large number of thin wafers with a wire running on a cylindrical workpiece such as a semiconductor ingot, ceramic or glass. The present invention relates to a device for detecting the amount of wire wear of a wire saw.

[0002]

2. Description of the Related Art A wire saw is one of the cutting devices for cutting a workpiece such as a semiconductor ingot, ceramic, glass or the like into a thin wafer. In this wire saw, a wire is wound around a plurality of grooved rollers to form a wire row, and one end of the wire is wound on one wire reel and the other end is wound on the other wire reel. Is done. When the wire reciprocates between one wire reel and the other wire reel at a high speed, the workpiece is pressed against the wire row and a processing liquid containing abrasive grains is supplied to the wire row. The workpiece is cut into many thin wafers by the lapping action of the abrasive grains.

[0003] Since the wire of this wire saw is worn while cutting the workpiece, there is a danger that the wire will break during cutting. Therefore, it is necessary to periodically detect the amount of wear of the wire and replace the wire before disconnection. Conventionally, wire wear of a wire saw is detected by temporarily stopping the wire saw when a wire has been used for a certain period of time, and then measuring the wire diameter with a micrometer to detect the wire wear. Then, if the wire is worn to a predetermined thickness, the wire is replaced.

[0004]

However, the conventional method for detecting the amount of wire wear of a wire saw cannot continuously detect the amount of wire wear, and therefore the method for detecting the amount of wire wear between the wire diameter measurement and the next measurement is not possible. There was a danger that the wire would break and the work would stop. In addition, since the wire saw must be stopped each time measurement is performed, there is a disadvantage that work efficiency is deteriorated.

[0005] From such a viewpoint, the applicant of the present invention provides:
A method has been proposed in which a voltage is applied between two points of the wire running path having only the electric resistance of the wire and the amount of wear of the wire is detected based on a change in the voltage. This method has an advantage that the wire wear amount can be continuously detected while the wire is running. However, since this method is an indirect method of measuring the amount of wire wear by measuring the electrical resistance of the wire, external factors (for example, electrical resistance other than the wire) that reduce the reliability of the measurement may cause a problem. There was a disadvantage that it was easily included.

The present invention has been made in view of such circumstances, and it is possible to automatically detect the amount of wire wear without stopping the operation of the wire saw, and obtain highly reliable measurement results. It is an object of the present invention to provide a wire abrasion detection device for a wire saw.

[0007]

According to the present invention, in order to achieve the above object, a workpiece is pressed against a wire reciprocating between one wire reel and the other wire reel, and the wire is ground. Supply machining fluid containing grains,
In a wire saw for cutting the workpiece into a large number of thin wafers, a movable head for holding the wire is provided, and a measuring head for detecting a moving displacement of the probe is provided. And a calculation unit for calculating a wire diameter based on the amount of displacement of the tracing stylus when attached.

[0008]

According to the present invention, the wire is clamped by the measuring head, and the wire diameter is calculated by the calculating section based on the displacement of the tracing stylus of the measuring head. Thereby, since the wire diameter can be directly measured, a highly reliable measurement result can be obtained.

In addition, if the measurement is performed when the traveling of the wire is temporarily stopped when the direction of the wire reciprocates, the measurement can be performed without stopping the operation of the wire saw. Further, since the pressing means is provided, the wire diameter can be measured without being affected by the tension of the wire. Further, a removing means for removing the working fluid supplied to the wire is provided upstream of the measuring head in the wire running direction. Thereby, since the processing liquid does not adhere to the wire at the time of measurement, more accurate measurement can be performed.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an apparatus for detecting the amount of wear of a wire saw according to the present invention; Before explaining an embodiment of the wire wear amount detecting device for a wire saw according to the present invention, first, a wire saw 1 will be described.
0 will be described with reference to FIG. As shown in FIG. 1, a wire 14 wound around one of the reels 12 includes a wire guide device 16, a plurality of fixed guide rollers 18, and 1.
8. Three grooved rollers 2 via dancer rollers 20
After forming a wire row 24 by successively winding the wires 2, 22, and 22, a wire running path is formed through a plurality of fixed guide rollers 18, 18, a dancer roller 20, and a wire guide device 16 to be wound on the other reel 26. I do.

A weight 44 having a predetermined weight is suspended from the dancer roller 20, and a predetermined tension is always applied to the wire 14 traveling on the wire traveling path by the load of the weight 44.
In the middle of the wire traveling path, a wire cleaning device 46 is provided.
The processing liquid 40 attached to the wire 14 is removed from the wire 14 by the wire cleaning device 46. Each of the reels 12 and 26 is connected to drive motors 28 and 30 that can rotate forward and reverse, and one of the three grooved rollers 22 is connected to a drive motor 32 that can rotate forward and reverse. . As a result, the wire 14 unreeled from one reel 12 moves at a high speed (600 m / min or more) in the direction of the solid arrow 34 in FIG.
It is wound by 6. The wire 14 wound on the other reel 26 runs backward in the direction of the dashed arrow 36 in the drawing and is wound on the one reel 12. That is, the wire 14
Reciprocates between one reel 12 and the other reel 26. Further, the wire row 24 has an abrasive liquid storage tank 38.
A working fluid 40 containing abrasive grains (usually, those having a GC of about $ 600 to $ 1000) is supplied from a grinding fluid supply nozzle 42.

A work feed table 48 is provided below the wire row 24. The work feed table 48 is driven by a screw rod 52 rotated by a motor 50 in a cutting feed direction (Y-Y direction in the drawing). A semiconductor ingot 54, which is a workpiece, is supported via a work block 56 and a slice base 58 on the side of the wire row 24 of the work feed table 48 while being movably provided. As a result, when the work feed table 48 is moved in the cutting feed direction (the wire row 24 side), the semiconductor ingot 5
4 is pressed against the wire row 24 running at a high speed, and cuts the semiconductor ingot 54 into a number of thin wafers by a lapping action of abrasives of the working fluid 40 supplied to the wire row 24.

Next, an apparatus for detecting the amount of wire wear of a wire saw according to the present invention will be described. FIG. 2 is a block diagram showing a configuration of the wire wear amount detecting device. As shown in the figure, the wire wear detecting device 60 mainly includes a table 62, a tracing stylus 64, a measuring head 66, an air cylinder 68, and a CPU 70. Table 6
Reference numeral 2 is installed near the wire 14, and a reference surface 62 </ b> A is formed on a surface facing the wire 14.

The tracing stylus 64 is arranged on the opposite side of the reference surface 62A of the table 62 with respect to the wire 14, and is movably supported by the measuring head 66. The measuring head 66 detects the amount of displacement of the tracing stylus 64 with respect to the reference surface 62A of the table 62 by a detection unit (for example, a differential transformer, a moiré scale, etc.) built in the measuring head 66, and An output voltage is generated in accordance with the amount of displacement. Then, the output voltage is converted into a digital signal by the A / D converter 71 and output to the CPU 70.

The air cylinder 68 is connected to a rod 69 via a support member 72 to a tracing stylus 64, and moves the tracing stylus 64 forward and backward with respect to a reference surface 62A of a table 62. Next, a method of measuring the wire diameter by the wire wear amount detecting device 60 configured as described above will be described.

First, a reference measurement is performed before measuring the wire diameter. That is, the air cylinder 68 is operated without the wire 14 between the probe 64 and the reference surface 62A of the table 62, and the probe is operated. 64 is brought into contact with the reference surface 62A. Then, the CPU 70 performs zero adjustment so that the displacement amount of the tracing stylus 64 at this time becomes a reference value (zero).

Next, the wire diameter is measured as follows.
In the wire saw 10 described above, the wire 14 reciprocates between one wire reel 12 and the other wire reel 26 (see FIG. 1). Therefore, when the wire 14 changes the traveling direction in the reciprocating motion, the wire 14 temporarily stops traveling. At this time, drive motors 28 and 30 connected to the wire reels 12 and 26 and the grooved roller 22,
The driving of 32 is also temporarily stopped.

When the CPU 70 confirms that the drive motor 30 has stopped, it drives the air cylinder 68 to move the tracing stylus 64 toward the reference surface 62A of the table 62. When the tracing stylus 64 is moved toward the reference surface 62A of the table 62, the wire 14 is located between the reference surface 62A of the table 62 and the tracing stylus 64. Sandwiched between.
The measuring head 66 detects the amount of displacement of the tracing stylus 64 when the wire 14 is clamped between the tracing stylus 64 and the reference surface 62A of the table 62, and outputs it to the CPU 70.

The CPU 70 compares the displacement amount output from the measuring head 66 with the reference value (zero) to calculate the displacement difference of the tracing stylus 64. Since the calculated displacement difference is the outer diameter of the wire 14, the CPU 7
0 is a value within the usable area of the wire (usually 0.
18 to 0.13 mm). If the calculated value is smaller than the usable area, C
The PU 70 activates the alarm device 76 to notify the worker that it is time to replace the wire.

When a series of measuring operations is completed, the CPU 70 drives the air cylinder 68 again to
To its original position. As described above, according to the wire abrasion amount detecting device for the wire saw of the present embodiment, the diameter of the wire 14 is measured by directly contacting the tracing stylus 64, so that a highly reliable measurement result can be obtained. . Also,
Since the amount of wear of the wire 14 can be automatically detected without stopping the operation of the wire saw 10, work efficiency can be improved.

In this embodiment, the wire 14 is pressed against the table 62 by the tracing stylus 64 as means for pressing the wire 14 against the table 62.
As shown in FIG. That is, the second air cylinder 78 is installed on both sides of the tracing stylus 62, and the wire 14 is pressed against the table 62 in advance at the time of measurement. This eliminates the need for the tracing stylus 64 to press the wire 14 against the reference surface 62A of the table 62 against the tension of the wire 14, so that the pressure for pinching the wire 14 can be reduced and the wire 14 64 and the reference surface 62A.

As shown in FIG. 3, a felt 80 is provided on the grooved roller 22 (not shown) side of the wire abrasion detecting device 60 to apply abrasive particles, cleaning liquid, etc., which have been attached to the wire 14 in advance. If you start measuring after wiping the kimono,
Further, a highly reliable measurement value can be obtained.

[0023]

As described above, according to the apparatus for detecting the amount of wear of a wire saw according to the present invention, the diameter of the wire is directly measured, so that the measurement can be performed reliably and a highly reliable measurement result can be obtained. . Further, since the amount of wear of the wire can be automatically detected without stopping the operation of the wire saw, work efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a wire saw.

FIG. 2 is a configuration diagram of a wire wear amount detecting device for a wire saw according to the present invention.

FIG. 3 is a configuration diagram when a second air cylinder is installed in the wire wear amount detecting device of the wire saw.

[Description of Signs] 10 ... Wire saw 14 ... Wire 12, 26 ... Wire reel 22 ... Groove roller 28, 30, 32 ... Drive motor 60 ... Wire wear amount detecting device 62 ... Table 64 ... Measuring element 66 ... Measuring head 68 ... air cylinder 70 ... CPU 76 ... alarm device 78 ... second air cylinder 80 ... felt

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B28D 5/04 B24B 27/06

Claims (3)

(57) [Claims] 1. A workpiece is pressed against a wire that reciprocates between one wire reel and the other wire reel, and a working fluid containing abrasive grains is supplied to the wire.
In a wire saw for cutting the workpiece into a number of thin wafers, a wire traveling stop when the direction of the wire reciprocatingly traveling is changed.
A measuring head that has a movable measuring element that clamps the wire when stopped, and detects a moving displacement amount of the measuring element; and a wire diameter based on the moving displacement amount of the measuring element when the wire is clamped. And a calculating part for calculating the wear amount of the wire saw. 2. A wire saw according to claim 1, further comprising pressing means for pressing said wire against a receiving surface of said measuring head before clamping said wire with said measuring head. Quantity detection device. 3. The apparatus according to claim 1, further comprising a removing means for removing the working fluid supplied to the wire at an upstream side of the measuring head in the wire running direction.