JP2000218500A - Wire saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically judge the abnormality of a device by operating the difference of detection values of a pair of flow meters, comparing the result of the operation with a predetermined allowable value, and judging the abnormality of the device when the result of the operation is over the allowable value. SOLUTION: A flow rate E of the slurry flowing in a slurry feed piping 64 is detected by a second flow meter 66. A flow rate F of the slurry flowing in a slurry recovering pipe 38 is detected by a third flow meter 68. Then the difference G (absolute value) between the detected flow rates E, F is operated. The operated value G is compared with a predetermined allowable value H (set by an operator on the basis of the past operation data and the like). When the operated value G is over the allowable value H (in a case of G>=H), the abnormality of the device (clogging of the slurry feed piping 63 and the slurry recovering pipe 38) is informed to an operator by the lighting of a warning lamp or by a buzzer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a wire saw.
In particular, the present invention relates to a wire saw for cutting brittle materials such as silicon, glass, and ceramic.

[0002]

2. Description of the Related Art A wire saw is made to run a wire train stretched at a predetermined pitch, and a slurry (working fluid) is applied to the wire train.
Is a device that cuts a large number of wafers simultaneously by pressing an ingot while supplying the wafers. Generally, the slurry used in the wire saw is circulated and used, and the slurry stored in the tank is fed by a pump to be supplied to a wire row, and the supplied slurry is collected and reused by an oil pan.

[0003] Slurries used in such wire saws contain abrasive grains, so that there is a problem that pipes are easily clogged. When this slurry piping is clogged,
There has been a problem that the supply amount of the slurry to the wire row changes and the cutting accuracy is reduced, and the slurry overflows from the tank. Conventionally, the degree of clogging of the pipe has been confirmed by an operator visually checking the amount of slurry supplied to the wire row. Alternatively, the flow rate of the slurry returned to the tank has been confirmed visually by an operator.

[0004]

However, if the state of clogging of the piping is confirmed by the conventional method, individual differences occur,
There is a disadvantage that accurate judgment cannot be made. Therefore, there is a problem that cutting with stable accuracy cannot be performed. The present invention has been made in view of such circumstances,
An object of the present invention is to provide a wire saw capable of automatically determining a device abnormality.

[0005]

According to the first aspect of the present invention, in order to achieve the above object, an ingot is run while a wire train stretched at a predetermined pitch is run and a working fluid is circulated and supplied to the wire train. By pressing, a wire saw that cuts the ingot into a plurality of wafers, is provided at a predetermined distance in the flow path through which the processing liquid flows, and a pair of flow rate detection means for detecting the flow rate of the processing liquid,
Calculating means for calculating the difference between the detection values of the pair of flow rate detecting means; comparing the calculation result of the calculating means with a preset permissible value; And characterized in that:

According to the present invention, when the difference in the flow rate of the machining fluid between the two points exceeds an allowable value, it is determined that the apparatus is abnormal.
That is, if the difference in the flow rate of the machining fluid between the two points exceeds an allowable value, it is possible that the flow path between the two points is clogged.
Further, in order to achieve the above object, the invention according to claim 2 runs a wire row stretched at a predetermined pitch, and presses an ingot while circulating and supplying a working fluid to the wire row. In a wire saw that cuts an ingot into a plurality of wafers, a rotation speed detection unit that detects a rotation speed of a pump that sends the processing liquid, and a flow detection unit that detects a flow rate of the processing liquid sent by the pump. A storage unit in which a set flow rate of the working fluid corresponding to the rotation speed of the pump is stored, and a set flow rate of the working fluid corresponding to the rotation speed detected by the rotation speed detection unit is obtained from the storage unit, Determining means for comparing with a detected value of the flow rate detecting means and determining that the apparatus is abnormal when the detected value is smaller than the set flow rate.

According to the present invention, a device abnormality is determined as follows. First, the rotation speed of the pump is detected by the rotation speed detecting means. Next, the set flow rate of the working fluid is obtained from the storage unit based on the detected rotation speed of the pump. Next, the set flow rate is compared with a value detected by the flow rate detecting means. As a result, if the detected value is lower than the set flow rate, it is determined that the apparatus is abnormal. That is, if the detected value is lower than the set flow rate, it is considered that the pipe is clogged or the impeller of the pump is worn or the like, so that it is determined that the apparatus is abnormal.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a wire saw according to the present invention. As shown in FIG. 1, the wire saw according to the present embodiment mainly includes a wire saw main body 10 that cuts an ingot In, and a slurry supply unit 50 that supplies slurry to a cut portion of the wire saw main body 10.

First, the configuration of the wire saw main body 10 will be described. As shown in FIG. 1, the wire saw main body 10 is provided with a pair of wire reels 12 (only one side is shown in FIG. 1). The wire 14 unwound from the wire reel 12 on one side has many guide rollers 16, 1
6, ... wound around four groove rollers 18A,
Guided to 18B, 18C, 18D. Then, a horizontal wire row 20 is formed by being wound around the four groove rollers 18A to 18D at a constant pitch. The wire 14 forming the wire row 20 is guided by the guide rollers 16, 16,... Again to the other wire reel (not shown), and is wound up on the other wire reel.

A wire guide device 22 and a dancer roller unit 24 are provided on the wire running paths formed on both sides of the wire row 20 by the guide rollers 16, 16, respectively (only one side is shown). . The wire guiding device 22 guides the wire 14 to be unwound from the wire reel 12 at a constant pitch, and guides the wire 14 to be wound around the wire reel 12 at a constant pitch. The dancer roller unit 24
Applies a certain tension to the wire 14 by winding the wire 14 around a dancer roller to which a dead weight has been added.

The four groove rollers 18A to 18D
One of the groove rollers 18C and the pair of wire reels 12 are respectively provided with a motor 2
6, 28 are connected. The wire 14 wound between the pair of wire reels 12 is a motor 26,
By driving the motors 28 in synchronization with each other, the vehicle travels at a high speed. As a result, the wire array 20 travels at a high speed.

A work feed table 30 is provided above the wire row 20. The work feed table 30 is slidably provided on a vertically extending feed base 32. By driving a work feed motor 34 installed on the feed base 32, the work feed table 30 is perpendicular to the wire row 20. To go up and down. An ingot In which is a workpiece is attached to a lower portion of the work feed table 30.

On the other hand, an oil pan 36 is provided below the wire row 20. As will be described later, a slurry is supplied to the wire row 20 at the time of cutting, and the supplied slurry is collected by the oil pan 36. A slurry recovery pipe 38 shown in FIG. 2 is connected to the center of the oil pan 36. The slurry recovery pipe 38 is connected to the buffer tank 40, whereby the slurry recovered in the oil pan 36 is stored in the buffer tank 40 via the slurry recovery pipe 38. Buffer tank 40
Is a tank for temporarily storing the slurry, and the slurry stored in the buffer tank 40 is sent to the slurry tank 54 of the slurry supply unit 50 by the slurry recovery pump 42 installed above the buffer tank 40. .

The buffer tank 40 is provided with a liquid level meter 43 for measuring the liquid level of the slurry, and the liquid level of the slurry stored in the buffer tank 40 is measured by the liquid level meter 43. The liquid level information of the slurry measured by the liquid level gauge 43 is output to the control device 80, and the control device 80 controls the rotation speed of the slurry recovery pump 42 according to the liquid level information to thereby output the slurry from the buffer tank 40. The amount of liquid sent to the slurry tank 54 is controlled. For example, when the liquid level of the slurry is high, the number of revolutions of the slurry collection pump 42 is increased to increase the discharge rate. Conversely, when the level of the slurry is low, the number of revolutions of the slurry collection pump 42 is decreased. To reduce the discharge amount. Thus, even if the amount of slurry sent from the slurry collection pipe 38 to the buffer tank 40 fluctuates, the slurry in the buffer tank 40 does not overflow.

The buffer tank 40 and the slurry tank 54
A check valve (not shown) is provided in the slurry collection pipe 44 connecting the first and second pipes. This check valve is controlled by the control device 8.
The opening / closing is controlled by 0, and is closed when the supply of the slurry from the buffer tank 40 to the slurry tank 54 is stopped. As a result, the slurry tank 54 and the buffer tank 4
Backflow of the slurry to zero is prevented, and fluctuation of the liquid level of the slurry in the slurry tank 54 is prevented.

The slurry recovery pipe 44 has a first
A flow meter 46 is provided. This first flow meter 46
The flow rate of the slurry flowing in the slurry collection pipe 44 is detected,
The detected value is output to the control device 80. Control device 80
Detects the presence or absence of clogging of the pipe based on the obtained flow rate information. A specific detection method will be described later in detail.

The wire saw main body 10 is configured as described above. Next, the configuration of the slurry supply unit 50 will be described. As shown in FIG. 1, the slurry supply unit 50 is configured by mounting a slurry tank 54, a heat exchanger 56, a slurry supply pump 58, a circulation pump 60, and the like on a movable carriage 52. The slurry supply pump 58 is provided as shown in FIG.
As shown in the figure, the slurry supply pump 58 is provided above the slurry tank 54, and the slurry tank 5
The slurry in 4 is sent to slurry supply nozzles 62, 62 installed above the wire row 20. Thus, the slurry is supplied to the wire row 20.

Here, the slurry supply nozzles 62, 62
The slurry is sent through the slurry supply pipe 64. In this slurry supply pipe 64, as shown in FIG.
The second flow meter 6 is located upstream (near the slurry supply pump 58).
6 are installed. The second flow meter 66 detects the flow rate of the slurry flowing in the slurry supply pipe 64 and outputs the detected value to the control device 80.

A third flow meter 68 is provided on the slurry collection pipe 38 for sending the slurry collected by the oil pan 36 to the buffer tank 40. This third flow meter 68
Detects the flow rate of the slurry flowing in the slurry collection pipe 38 and outputs the detected value to the control device 80. The control device 80 detects whether or not the pipe is clogged based on the flow rate information detected by the second flow meter 66 and the third flow meter 68. Further, the slurry supply pump 58 is controlled based on the obtained flow rate information (the amount of slurry supplied is controlled). A specific method for detecting the clogging of the slurry supply pipe 64 will be described later.

The heat exchanger 56 exchanges heat of the slurry stored in the slurry tank 54. A circulation path is formed by a circulation pipe 70 between the heat exchanger 56 and the slurry tank 54, and the slurry stored in the slurry tank 54 is sent by the circulation pump 60 to the heat exchanger 56. Circulated supply. The circulation pipe 70 is provided with a temperature control valve 72. By closing the temperature control valve 72, the slurry stored in the slurry tank 54 is heated by the heat generated by the circulation pump 60.

The temperature control valve 72 and the circulation pump 6
0 is controlled by the control device 80, and the control device 80 controls the slurry tank 5 measured by the temperature sensor 74.
The temperature control valve 72 and the circulation pump 60 are controlled based on the temperature of the slurry in 4. For example, when the temperature of the slurry measured by the temperature sensor 74 is higher than the set temperature,
The temperature control valve 72 is opened to circulate and supply the slurry to the heat exchanger 56. When the temperature of the slurry is low, the temperature control valve 72 is closed and the slurry is heated by the heat generated by the circulation pump 60.
As a result, the temperature of the slurry in the slurry tank 54 is kept constant.

The slurry supply unit 50 is configured as described above. In the wire saw configured as described above,
The ingot In is cut as follows. First, the ingot In is mounted on the work feed table 30.
Next, the wires 14 are driven at high speed by synchronously driving the motors 26 and 28. Thereby, the wire row 20 runs at high speed.

Next, the work feed table 30 is lowered toward the wire row 20. At the same time, the slurry supply pump 58 is driven to send the slurry from the slurry tank 54 to the slurry supply nozzles 62, 62. Thereby, the wire row 2 traveling at high speed from the slurry supply nozzles 62, 62
Slurry is supplied to the ingot I
n descends toward this wire row 20.

As a result, the ingot In is pressed against the high-speed running wire row 20 and is simultaneously cut into a large number of wafers by the lapping action of the slurry supplied to the wire row 20. At the time of processing, the wire row 2
The slurry supplied to the tank 0 is collected by the oil pan 36, temporarily stored in the buffer tank 40, and then returned to the slurry tank 54 via the slurry collection pipe 44.

By the way, the wire saw according to the present embodiment cuts the ingot In as described above. When cutting the ingot In, the wire saw according to the present embodiment determines whether there is any device abnormality before the start of cutting, that is, whether the pipe is connected to the pipe. Self-check for clogging. The self-check is automatically performed by the control device 80, and the self-check is performed according to the flow shown in FIG.

First, when an operation start signal is received from an operation panel (not shown) by the operator, the control device 80 drives the slurry supply pump 58 to send the slurry from the slurry tank 54 to the slurry supply nozzles 62, 62. I do. Thereby, the slurry is supplied from the slurry supply nozzles 62, 62 toward the wire row 20. At the same time, the controller 80 drives the slurry collection pump 42 to send the slurry from the buffer tank 40 to the slurry tank 54.

Next, flow rate detection by each flow meter is started (S1). First, the flow rate E of the slurry flowing through the slurry supply pipe 64 is detected by the second flow meter 66 (S2).
Next, the flow rate F of the slurry flowing through the slurry collection pipe 38 is detected by the third flow meter 68 (S3).

Next, the flow rate E detected by the second flow meter 66
And the difference G (absolute value) between the detected flow rate F and the third flow meter 68
Is calculated (S4). Next, the calculated value G is compared with a preset allowable value H (set by an operator based on past operation data and the like) (S5). As a result of this comparison, when the calculated value G exceeds the allowable value H (G ≧ H
), The operator is alerted by a warning light or a buzzer, etc.
8 is clogged (S6). The operator cleans the slurry collection pipe 38, the oil pan 36, and the like based on this.

On the other hand, when the operation value G does not exceed the allowable value H (when G <H), the process proceeds to the next step. Next, a second embodiment of the wire saw according to the present invention will be described. In the wire saw according to the second embodiment,
The presence or absence of a device abnormality is inspected from the relationship between the pump rotation speed and the slurry flow rate. The specific configuration is as follows.

As shown in FIG. 2, in the wire saw of the first embodiment described above, the slurry recovery pump 42 and the slurry supply pump 58 are provided with encoders 82 and 84 for detecting the rotation speed of the pump, respectively. I have.
Each of the pumps 42 detected by the encoders 82 and 84,
The rotation speed of 58 is output to the control device 80. On the other hand, as shown in FIG.
The set flow rate of the slurry corresponding to the number of rotations is stored. The control device 80 checks whether there is a device abnormality by detecting whether the actual flow rate is lower than the set flow rate. More specifically, the flow is as shown in FIG.

Prior to the start of cutting, the control device 80 drives the slurry supply pump 58 to send the slurry from the slurry tank 54 to the slurry supply nozzles 62,62. Thereby, the slurry is supplied from the slurry supply nozzles 62, 62 toward the wire row 20. At the same time, the controller 80 drives the slurry collection pump 42 to send the slurry from the buffer tank 40 to the slurry tank 54.

Next, the controller 80 detects the rotational speed I of the slurry recovery pump 42 by the encoder 82 (S
7). Next, the set flow rate J of the corresponding slurry is acquired from the detected rotational speed I of the slurry collection pump 42 (S
8). Next, the slurry collection pipe 4 is measured by the first flow meter 46.
Then, the flow rate A of the slurry flowing through No. 4 is detected (S9).

Next, the actual flow rate A of the slurry detected by the first flow meter 46 is compared with the set flow rate J (S
10). As a result of this comparison, if the actual flow rate A of the slurry detected by the first flow meter 46 is lower than the set flow rate J (if A ≦ J), the operation is stopped. Then, the operator is informed of the occurrence of device abnormality (clogging of the slurry collection pipe 44, wear of the impeller of the slurry collection pump 42, etc.) by turning on a warning light or a buzzer (S11). The operator performs cleaning of the slurry collection pipe 44 and replacement of the impeller of the slurry collection pump 42 based on this.

On the other hand, if the detected value A exceeds the set flow rate J (A> J), the process proceeds to the next step. That is, the rotational speed K of the slurry supply pump 58 is detected by the encoder 84 (S12). Next, the set flow rate L of the corresponding slurry is acquired from the detected rotation speed K of the slurry supply pump 58 (S13).

Next, the flow rate E of the slurry flowing through the slurry supply pipe 64 is detected by the second flow meter 66 (S1).
4). Next, the actual flow rate E of the slurry detected by the second flow meter 66 is compared with the set flow rate L (S1).
5). As a result of this comparison, when the actual slurry flow rate E detected by the second flow meter 66 is lower than the set flow rate L (E
If ≤ L), the operation is stopped. Then, the operator is informed of the occurrence of device abnormality (clogging of the slurry supply pipe 64, wear of the impeller of the slurry supply pump 58, etc.) by turning on a warning light or a buzzer (S16). The operator replaces the impeller of the slurry supply pipe 64 and the slurry supply pump 58 based on the result.

On the other hand, if the detected value exceeds the set flow rate J (E> L), the cutting is started as it is (S17). As described above, according to the wire saw of the present embodiment, it is possible to automatically perform a self-check for the presence or absence of a device abnormality before the start of cutting. Thus, it is possible to prevent the cutting from being started in a state where the device abnormality has occurred, and it is possible to perform a stable operation.

In the same manner, clogging of the circulation pipe 70 and wear of the impeller of the circulation pump 60 can be detected. In the present embodiment, a combination of the two inventions has been exemplified, but only in a piping system in which clogging is likely to occur,
Any one of the inventions may be applied, thereby reducing the cost of the device.

Further, in the above-described series of embodiments, the self-check is performed before the operation of the apparatus is started. However, a program for jumping from S17 to S1 may be executed at all times during the operation. Good. Further, the installation position and the number of each flow meter and the sequence of the self-check are not limited to those of the above-described embodiment. You may make it install in multiple places. For example, as shown in FIG. 6, a fourth flow meter 85 may be provided in the circulation pipe 70. Thereby, the clogging of the circulation pipe 70 can be accurately grasped.

The means for detecting the number of rotations of the pump is not limited to the encoder, but may be a rotation amount detecting means such as a tachogenerator or a resolver. Further, when an inverter motor or an AC motor is used as the pump driving means, the pump rotation command value may be used as the pump rotation speed.

[0040]

As described above, according to the wire saw according to the present invention, an abnormality of the apparatus can be automatically detected, so that a cutting failure and a failure of the apparatus can be prevented. In addition, high-precision cutting can be stably performed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the entire configuration of a wire saw.

FIG. 2 is a block diagram showing a configuration of a main part of the wire saw according to the present invention.

FIG. 3 is a flowchart of a self-check system.

FIG. 4 is a graph showing a relationship between a pump rotation speed and a set flow rate of a slurry.

FIG. 5 is a flowchart of a self-check system.

FIG. 6 is a block diagram showing a configuration of a main part of another embodiment of the wire saw according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Wire saw main body 14 ... Wire 20 ... Wire row 36 ... Oil pan 40 ... Buffer tank 44 ... Slurry recovery piping 46 ... 1st flow meter 50 ... Slurry supply unit 54 ... Slurry tank 56 ... Heat exchanger 62 ... Slurry supply nozzle 64 ... Slurry supply pipe 66 ... Second flow meter 68 ... Third flow meter 82,84 ... Encoder 85 ... Fourth flow meter

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Hiroshi Oishi, 555-1 Nakanoya, Annaka-shi, Gunma Inside the Super Silicon Research Laboratories Co., Ltd. (72) Keiichiro Asakawa 555-1, Nakanoya, Annaka-shi, Gunma Inside the Super Silicon Research Laboratories (72) Inventor Junichi Matsuzaki 555-1, Nakanotani, Annaka-shi, Gunma F-term inside the Super Silicon Research Laboratories (reference) 3C047 FF15 GG19 3C058 AA05 AB08 AC02 AC04 BB02 BB06 BB08 BB09 BC03 CA01 CA04 CA05 CA06 CB06 DA03

Claims (2)

[Claims] 1. A wire saw that cuts an ingot into a plurality of wafers by running a wire row stretched at a predetermined pitch and pressing an ingot while circulating and supplying a processing liquid to the wire row. A pair of flow rate detection means provided at a predetermined distance in the flow path of the processing fluid and detecting a flow rate of the processing fluid; a calculation means for calculating a difference between detection values of the pair of flow rate detection means; and the calculation means And a judgment means for comparing the calculation result of (1) with a preset allowable value, and judging that the apparatus is abnormal when the allowable value is exceeded. 2. A wire saw which cuts an ingot into a plurality of wafers by running a wire row stretched at a predetermined pitch and pressing an ingot while circulating and supplying a processing liquid to the wire row. Rotation speed detection means for detecting the rotation speed of a pump for feeding the processing fluid; flow rate detection means for detecting the flow rate of the processing fluid fed by the pump; setting of the processing fluid corresponding to the rotation speed of the pump A storage unit in which the flow rate is stored, a set flow rate of the working fluid corresponding to the rotation speed detected by the rotation speed detection unit is obtained from the storage unit, and is compared with a detection value of the flow rate detection unit. And a determination means for determining that the apparatus is abnormal when the flow rate falls below a set flow rate.