JPH0439005A - Slicing machine and its control method - Google Patents

Abstract

PURPOSE:To reduce dispersion in facial accuracy of a processed surface and thicknesses, by a method wherein a displacement quantity of a rotary axial direction of a cutting tool is detected by a plurality of displacement detectors, an actual displacement quantity of a cut off part is calculated through operation and controlled so that the displacement quantity becomes zero. CONSTITUTION:The first displacement detector 41 is installed most close by an ingot 34 and a displacement quantity A of a blade 51 is detected. The second displacement detector 42 installed to a position separated from the ingot 34 and a displacement quantity B of the blade 51 is detected. The maximum displacement quantity of the central part of a cut point and an inclination angle of the blade 51 are calculated in consideration of both the detected quantities A, B, a space up to the center of both the displacement detectors 41, 42 from the center of a cutting width of a cutting edge 52 of the blade 51 at the time of cutting of the ingot 34 and rigidity to bending of the blade 51. Control is performed so that both of them become zero. With this construction, control is performed so that displacement of a cutting tool is not generated substantially and a work is free from dispersion in thicknesses and facial accuracy of a processed surface is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a slicing machine used, for example, to thinly slice silicon wafers from a silicon ingot, and a method for controlling the same.

[Prior Art] Generally, in a slicing machine, a cutting tool having a seven-circular cutting edge on the inner circumference is attached to a tool mount, and this cutting tool is driven to rotate, and the rotating cutting tool is sent to a workpiece. The workpiece is then moved, or the workpiece is fed and moved relative to the cutting tool to be cut. Such a cutting method makes it possible to efficiently cut thin silicon wafers from a silicon ingot.

However, in such cutting methods, changes in cutting resistance due to changes in cutting arc length between the cutting edge and the workpiece, or
Changes in cutting resistance due to wear and clogging of the cutting edge cause the cutting edge to be displaced along the rotational axis direction, in other words,
This will cause it to bend.

The problem is that the straightness of the cut surface of the cut workpiece deteriorates, and after cutting starts, the relative positional relationship between the cutting surface position of the cutting tool and the silicon ingot changes due to thermal expansion due to the temperature rise of the main shaft, etc. However, it has been pointed out that the thickness of the cut silicon wafer changes.

For this reason, in conventional slicing machines, the deflection of the blade is measured while cutting the workpiece, and if the measured deflection becomes large, the cutting speed is slowed down, as shown in Japanese Patent Application Laid-Open No. 62-70904. , which attempts to improve the straightness of cutting, and measures the deflection of the blade during cutting, as shown in Japanese Unexamined Patent Publication No. 1-182011.

It is known that the straightness of the blade is improved by increasing or decreasing the number of rotations of the blade rotating body based on the measured amount of deflection of the blade.

[Problem to be solved by the invention] However, in such a conventional configuration.

The relationship between cutting speed and blade deflection is not constant;
Furthermore, due to the mutual positional relationship between the inner peripheral blade and the ingot to be cut, it is impossible for the blade deflection detector to detect the actual amount of deflection at the cutting site, and the displacement detected by the displacement detector is set to zero. Even if an attempt is made to increase or decrease the number of revolutions so that

This method has the problem that it is difficult to improve the surface accuracy of the cut surface of the workpiece.

Furthermore, no consideration is given to changes in the relative position of the cutting part of the blade and the silicon ingot due to thermal expansion caused by temperature rise in the two rotating parts, etc., and changes in the thickness of the cut wafer are eliminated. It has not been.

This invention was made in view of the above-mentioned problems, and an object of the invention is to reduce the surface accuracy and thickness variation of the machined surface of a workpiece with a simple structure and at low cost. An object of the present invention is to provide a slicing machine that can perform the following functions, and a method for controlling the slicing machine.

[Means to solve the problem] The above-mentioned HI! In order to solve the problem and achieve objective i.

The slicing machine of the present invention includes an annular cutting tool having a cutting edge on the edge of an inner dish, a rotating shaft to which this cutting tool is attached and supported so that it can be driven two rotations, and a rotating shaft that is rotated by centrifugal force generated by nine rotations according to the number of rotations. A supported rotary body having a structure that is displaced along a direction, and a plurality of displacement detectors arranged at predetermined intervals in the vicinity of the cutting tool, and detecting the amount of displacement of the cutting tool during cutting. From the displacement detection means consisting of a device and the amount of displacement detected by this detection means,
an actual displacement calculating means for calculating the amount of displacement at the actual cutting site; and an actual displacement calculating means for calculating the actual displacement 1-compensating rotation speed of the rotating body so as to make the actual displacement calculated by the actual displacement calculating means zero. The present invention is characterized by comprising a displacement compensation calculation means and a tool rotation speed control means for correcting the rotation speed of the rotating body using the actual displacement compensation rotation speed calculated by the actual displacement compensation calculation means.

Further, in the slicing machine of the present invention, the displacement detecting means detects the amount of displacement immediately before the start of cutting, and so that this value becomes equal to the value at the time when the main shaft is started for the first time and the main shaft reaches the reference rotation speed. A thermal displacement compensation calculation means for calculating a thermal displacement compensation rotation speed of the rotary body, and a tool rotation speed control means for correcting the rotation speed of the rotary body using the thermal displacement compensation rotation speed calculated by the thermal displacement compensation calculation means. It is characterized by having the following.

The slicing machine of the present invention may further include dressing timing detection means for issuing a dressing command for the cutting tool when the actual displacement calculated by the actual displacement calculation means exceeds a predetermined value. It is a feature.

In addition, the method for controlling a slicing machine of the present invention includes a rotating body that is supported so as to be able to be driven one rotation, and a cutting blade is provided on the inner peripheral edge of the rotating body that is supported so as to be displaced along the rotational axis direction by the centrifugal force of the rotating body. A displacement detection system that detects the amount of displacement of an annular cutting tool in the direction of the rotational axis when cutting an object by using a plurality of displacement detectors arranged at a predetermined interval near the cutting site of the cutting tool. The amount of displacement of the cutting tool detected by the detection means is
The present invention is characterized in that the actual displacement amount of the cut portion during cutting by the cutting tool is calculated, and the rotation speed of the rotating body is controlled so that the calculated displacement amount becomes zero.

[Operation] In the slicing machine according to the present invention configured as described above, the position of the cutting tool before the start of cutting is detected by the displacement detection means.

The thermal displacement compensation calculation means calculates the thermal displacement compensation rotation speed so that the position of the cutting tool is maintained at the position of the cutting tool when the spindle is first started and the rotation speed of the spindle reaches the reference rotation speed,
The rotational speed of the rotating body is corrected using this thermal displacement compensation rotational speed, and control is performed to maintain the first force position of the cutting tool at a constant position before the start of cutting.

Furthermore, the displacement of the cutting tool during cutting is detected by a plurality of displacement detectors, and based on the detected displacement amount, the actual maximum displacement amount of the cutting tool at the cutting site is calculated by an actual displacement calculation means, and this is calculated. The actual displacement compensation rotation speed of the nine rotating bodies that makes the calculated actual displacement amount zero is calculated by the actual displacement compensation calculation means, and the rotation speed of the rotating body is corrected and controlled using the actual displacement compensation rotation speed. The cutting tool is controlled to always remain in a fixed position.

In this way, displacement of the cutting tool is controlled so as not to occur substantially, and variations in the thickness of the workpiece and surface precision of the machined surface are maintained and improved.

[Embodiment] Hereinafter, an embodiment of a slicing machine and a control method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, this slicing machine 10 includes:
A silicon ingot 3-4 as a workpiece is thinly sliced to form a silicon wafer.9 A base 11 is fixed on a base (not shown), and a main shaft 8 is attached to this base 11! #155 is installed, and a main shaft 54 is rotatably supported on this main shaft mechanism 55 with the main shaft 54 extending in the vertical direction. A main shaft drive motor 59 is installed beside the main shaft mechanism 55 to rotate the main shaft 54 . On the other hand, a driven pulley 5 is attached to the end of the main shaft 54.
6 is fixed to the drive shaft 59a of the main shaft drive motor 59, and a drive pulley 58 is fixed to the drive shaft 59a of the main shaft drive motor 59. An endless belt 57 is connected between the driven pulley 56 and the driving pulley 58.
is being wound.

In this way, the main shaft 54 is rotationally driven as the main shaft drive motor 59 is activated.

A tension disk 53 is coaxially and integrally attached to the upper end of this main shaft 54. The upper end surface of this tension disk 53 is open over the entire surface,
A blade 51 made of an annular thin plate is stretched here so as to extend in the horizontal direction. This blade 51 has an opening formed in its center and has a so-called donut shape. A cutting edge (inner peripheral edge) 52 is formed on the inner peripheral edge of this blade 51 over the entire circumference. The blade 51 and the cutting edge 52 are made of silicon ingot 3.
This constitutes a cutting tool for slicing 4.

On the other hand, on the upper right side of the base 11 is a cutting feed slide 14,
A slide column 21 is provided on the cutting feed slide 14 so as to be slidable forward and backward in the left and right directions in the figure.

A cutting feed servo motor 13 is mounted on the right end of the cutting feed slide 14, and a cutting feed ball screw 12 is connected to the drive shaft 13a of the cutting feed servo motor 13 so as to rotate integrally therewith. ing. The other end of the cutting feed ball screw 12 is rotatably supported by the right end of the cutting feed slide 14. and,
A pole nut 22 for cutting and feeding, which is screwed into the ball screw 12 for cutting and feeding, is connected to a slide column 21.

In this way, in response to activation of the cutting feed servo motor 13, the slide column 21 is moved along the left and right direction in Figure 1, in other words, so as to slice the silicon ingot relative to the cutting tool. It turns out.

On the other hand, the aforementioned slide column 21 is equipped with an indexing feed 81 and an ellipse 35 for indexing and feeding only the required thickness when slicing the silicone Gott 34. That is, a 2 index feed guide 25 is installed on the left side of this slide column 21, and a 0 index feed guide 25 is attached to this index feed guide 25 so as to be slidable in the vertical direction. 1 at the top of
A servo motor 24 for indexing and feeding is installed.

A single index feed ball screw 23 is connected to the drive shaft 24a of the index feed servo motor 24 so as to rotate integrally therewith. A pole nut 31 for indexing feed is screwed into this ball screw 23 for indexing feed.
is attached to the indexing stand 32. Further, an ingot mounting stand 33 is attached to this indexing stand 32.

Cutting (slicing) this ingot mounting table 33
A silicon ingot 34 is attached so that the center axis of the silicon ingot 34 coincides with the center axis of the main shaft 54.

In this way, in response to activation of the 2nd index feed servo motor 24, the 1st index table 32 moves the silicon ingot 34 up and down along the vertical direction, in other words, to move the silicon ingot 34 in and out of the cutting tool. .

〉 The donut-shaped blade 51 constituting the above-mentioned cutting tool is made of an extremely thin steel plate of 1 mm or less, and the inner peripheral blade 52 is made of diamond particles sintered through a binder. There is. Furthermore, as described above, this blade 51 is extremely thin, so even if it is tensioned on the tension disk 53 with a predetermined tension, it will not be displaced along the axis of one revolution. there's a possibility that. That is, as the cutting slide column 21 is fed rightward, the cutting blade 52 comes into contact with the silicon ingot 34.

When slicing this, the blade 51 is displaced in the vertical direction due to a change in cutting resistance generated between the cutting blade 52 and the silicon ingot 34.

In order to detect the amount of displacement of this blade 51, the first displacement detector 41 is placed in a non-contact state with respect to this blade 51.
．． and a second displacement detector 42 are provided. Both displacement detectors 41 and 42.

It is formed from a so-called magnetic sensor and is configured to detect the distance to the corresponding surface of the blade 51 in a non-contact manner.

The first and second displacement detectors 41 and 42 for detecting the amount of displacement of the blade 51 are installed at predetermined positions along the inner peripheral edge of the blade 51, as shown in FIG. They are installed at intervals. That is, the first displacement detector 41 and the displacement detector 41 of the cutting tube 1 detect the cutting (
Silicon ingot to be sliced (sliced) 3
4 as close as possible to the second displacement detector 4.
2, the blade 51 is centered around the center of the blade 51.
It is mounted at a position away from the first displacement detector 41 on a concentric circle whose radius is from the center of the center to the center of the first displacement detector 41.

On the other hand, as shown in FIG. 2(b), the displacement of the blade 51 due to the change in cutting resistance during cutting is maximum at the center of the cutting part, and since the blade 51 is an elastic body, this displacement is The further away from the site, the smaller it becomes. blade 51
The maximum displacement of i.e.

It has been experimentally confirmed that the curvature of the cut surface of the goth is greatest at the center of the blade 51 along the cutting direction. However, it is impossible to detect the amount of displacement of the blade 51 at the location where the displacement of the blade 51 is maximum because the silicon ingot 34 being cut interferes with the location where the displacement detector is installed.

In other words, in the existing slicing machine blade displacement detection and displacement control methods, due to restrictions on the installation location of the displacement detector, it is difficult to completely reduce the blade displacement that occurs when cutting a silicon ingot to zero. In other words, the displacement of the blade is detected.
Even if it is possible to reduce the displacement of the blade to zero at the cutting site, a large displacement remains at the cutting site because the blade is an elastic body.

Therefore, in the present invention, in order to solve this problem, the first displacement detector 41 is installed closest to the ingot 34 to detect the displacement amount A of the blade 51, and the second displacement detector 42 is installed as described above. It is installed at a position away from the ingot 34 to detect the displacement amount B of the blade 51, and this re-detected amount A, B
and the cutting edge 52 of the blade 51 when cutting the ingot 34.
The maximum displacement at the center of the cutting point and the inclination angle of the blade 51 are calculated by taking into account the distance from the center of the cutting width to the center of the one-wheel displacement detector 41, 42, and the rigidity of the blade 51 against deflection. , are controlled so that both are zero.

Next, with reference to FIG. 3, the configuration of a feedback control system for straightening the cut surface of the silicon ingot 34 during slicing in this embodiment will be described.

Here, the first displacement detector 41. Second displacement detector 42
．． First initial value storage 61. Second initial value storage 63.
First subtractor 62. A block composed of the second subtractor 64 and the storage start command 81 is a displacement detection means 90 that detects the displacement of the blade 51. As mentioned above. 1st
The displacement signal output A from the displacement detector 41 is connected to the input terminal of the first initial value storage 61 and the positive input terminal of the first subtractor 62 . Furthermore, the storage signal output of the first initial value storage 61 is connected to the negative input terminal of the first subtracter.

This first. The second initial value storage units 61 and 62 are configured to receive a storage start command 81 to determine when to store them. It is configured to store the input values AO and BO at the time when the storage start command 81 is given, and output the stored values thereafter. In addition, this memory start command 81 is given as a short pulse command when the main shaft 54 is first activated and the main shaft rotational speed reaches the reference rotational speed when slicing (cutting) the silicon ingot 34. Blade 5 when energizing the slicing machine
This is for storing the position No. 1 as the initial position.

As a result, the first subtractor 6 during operation of the slicing machine
The output from 2 becomes A-AO and outputs only the displacement of the blade during operation.

This eliminates the effects of mounting position errors of the displacement detector.

Similarly, the displacement signal output from the second displacement detector 42 is
and an input terminal of the second initial value storage device 63.

The second initial value memory 63 is connected to the positive input terminal of the second subtracter, and similarly to the first initial value memory 61,
When the storage start command 81 is given and the blade rotation starts and reaches the reference rotation speed, the displacement of the blade is set as the initial value BO.
This is because the storage signal output BO of the second initial value storage 63 is connected to the negative input terminal of the second subtractor 64.

The output of the second subtractor 64 is B-BO, and only the displacement of the blade during operation is determined. In this way, the influence of mounting position errors is removed.

As described above, the first subtractor 62. Second subtractor 6
Both outputs of No. 4 result from the displacement of the blade 51. When approaching the direction of the second displacement detector 4142, the outputs of the first and second dividers 62 and 64 output signals in the (10) direction.

Second control switch 71. Thermal displacement compensating means 93 composed of third arithmetic unit 72 and second register/decoder 73
, a reference rotation speed setting device 73a, and a rotation speed setting command 82
The reference rotation speed setting means 94 is configured to set the reference rotation speed of the main shaft 54.

In the process of cutting the ingot 34, the main shaft 54 undergoes thermal displacement in the axial direction due to the temperature rise of the main shaft mechanism 55, resulting in a change in the positional relationship between the blade 51 and the ingot 34, that is, immediately after the main shaft 54 is started. The thickness of a silicon wafer sliced during a period of severe temperature rise gradient,
This prevents the thickness of the sliced silicon wafer from gradually changing until the spindle temperature reaches saturation after a considerable period of time has elapsed after starting the spindle.

In this operation, first, when starting the spindle 54 for the first time, the second control switch 71 is in an open state, and at the same time as the spindle start command is input, the 1 rotation speed setting command 82 is turned on instantaneously, and the reference rotation speed is set. The reference rotation speed set value set by the device 73a is written to the second register/decoder 73, and the contents of the second register/decoder 73 are transmitted to the motor drive controller 74, and the set and stored reference value is written to the second register/decoder 73. The main shaft drive motor 59 is excited so that the main shaft 54 rotates at the rotation speed, and feedback control is performed so that the main shaft 54 maintains the set reference rotation speed.

When the main shaft 54 reaches the set reference rotation speed, the storage start command 81 is input as described above.

The position of the blade 51 at that time is the first position. as well as being stored in the second initial value storage 61,63.

1st at this point. The outputs of the second subdividers 62 and 64 are both zero. Further, the second rotation speed setting command 82 is configured such that it is not issued during the cutting operation of the silicon ingot 34, and when the cutting operation of the silicon ingot 34 is completed and each part returns to its original position, and the reference rotation speed is reached. This command is issued only when the setting of the setting device 73a is changed. Note that when the 1 rotation speed setting command 82 is issued, the memory start command 8 is always issued.
1 is also input to update the blade position information.

The main shaft 54 has reached the reference rotation speed set by the reference rotation speed setting device 73a, and the first rotation speed has reached the reference rotation speed set by the reference rotation speed setting device 73a. Second double initial value storage 6
1 and 63 memorize the initial position of the blade, and when a cutting command is given, first, the second control start switch 71 is closed, and the displacement information of the blade 51 from the second displacement detector 42 is transferred to the second position. The signal is input to the third arithmetic unit 72 via the subtracter 64 . As mentioned above, this signal is first applied to the spindle 5.
The displacement of the blade 51 is based on the displacement of the blade 51 when the main shaft 54 reaches the set reference rotation speed after starting the main shaft 4. If there is no effect of temperature rise, such as immediately after starting the main shaft, the third The displacement information of the blade 51 input to the arithmetic unit 72 is zero, the output of the third arithmetic unit 72 also remains zero, the contents of the second register/decoder 73 are not rewritten, and the main shaft 54
continues to rotate at the initially set standard rotation speed. If a sufficient time has elapsed after starting the main shaft 54 before starting the cutting operation, or if thermal displacement appears due to the influence of temperature rise after several cutting operations, the second control is started. When the switch 71 is closed, a displacement signal indicating the displacement of the blade 5.1 from the initial position is input from the second subtractor 64 to the third computing unit 72 via the second control start switch 71. . The third arithmetic unit 72 calculates the magnitude (displacement amount) of the input signal.
, depending on the polarity (direction of displacement), the number of pulses of the pulse signal output (the number of rotations to compensate for thermal displacement of the main shaft) and the addition/subtraction sign (direction of compensation for the number of rotations) are output at the set period, and the second register/decoder 73 It is designed to increase/decrease the memory value of. Here, the relationship between the displacement of the blade 51 and the compensation rotation speed (number of pulses) can be determined at the time of design once the tension disk 53 to be used is determined, and the relationship between the displacement of the blade 51 and the compensation rotation speed (pulse number) can be determined at the design stage once the tension disk 53 to be used is determined.
The pulse output period in step 2 is set according to the time constant of the mechanical system.

This is also determined by the tension disc 53.

It can be determined in advance through step response tests and design calculations.

For example, the displacement signal from the second displacement detector 42 is
If the blade 51 is in a direction approaching the second displacement detector 42, the output from the third arithmetic unit 72 is added to the stored value of the second register/decoder 73 according to the amount of displacement of the blade 51. Become something. As a result, the rotational speed command value from the second register/decoder 73 becomes high, and the rotational speed of the main shaft drive motor 59 increases via the motor drive controller 74. Due to the increase in centrifugal force, the blade 51 A corrective movement is made in a direction away from the second displacement detector.

In this way, the corrective action is performed in a closed loop so that the blade 51 always maintains its initial position.

When the blade 51 reaches the initial position, the third computing unit 72
The zero detection signal 83 is sent out, the second control start switch 71 is opened, the thermal displacement compensation operation is ended, and the cutting operation is started.

- During cutting (slicing) of the silicon ingot 34,
The "warpage" of the blade 51 is controlled by the first computing unit 65. Actual displacement calculation means 91 composed of an actual displacement compensation coefficient setter 65a, a first control start switch 66, and a second calculation unit 6
7. It is performed by the actual displacement compensation calculation means 92 composed of the first register/decoder 68.

Here, the operations of the second arithmetic unit 67 and the first register/decoder 68 are similar to the operations of the third arithmetic unit 72 and the second register/decoder 73 described above.

First, before the cutting operation begins, the first control start switch 66 is closed, and then the cutting feed servo motor 13 is activated and the slide column 21 begins to move rightward in the figure, and the cutting operation begins.

When the cutting edge 52 of the blade 51 is not in contact with the silicon ingot 34, no bending force is applied to the blade 51, and no bending occurs in the blade 51.

Therefore, the first. The displacement signals from both the second displacement detectors 41 and 42- are both zero, and the displacement signals from the first and second displacement detectors 41 and 42- are both zero. The output signals from both the '2-th liquid calculators 62 and 64 are also zero. Therefore, the output signal from the first arithmetic unit 65 is also zero.

Now, the cutting edge 52 of the blade 51 is the silicon ingot 34.
When the cutting blade 52 comes into contact with the blade and is in the cutting operation, a bending force is generated on the blade 51 due to uneven wear, clogging, etc. on the cutting edge 52, or due to a change in the cutting arc length, etc. In the case of displacement along the rotational axis direction at the cutting site 9 For example,
When the blade 51 is displaced upward in FIG.
The displacement signals of the first and second displacement detectors 41 and 42 are as follows.

Increases in the (+) direction. At this time, the first displacement detector 4
Since the displacement detector 1 is installed close to the cutting site of the silicon ingot 34, it outputs a displacement signal with a large absolute value, and the second displacement detector 42 is installed away from the cutting site, so the first displacement detector 42 outputs a displacement signal with a large absolute value. The first . The displacement signals from both second displacement detectors 41 and 42 are
1st. The signal is input to the first computing unit 65 via the second both calculators 62 and 64. The first arithmetic unit 65
Using the polarity and absolute value of the displacement signals from both liquid calculators 62 and 64 and the setting value of the actual displacement compensation coefficient setter 65a,
The maximum displacement value at the center of the cutting arc of the blade 51 during cutting is calculated and output.

This displacement output signal is input to the second performer 67 via the first control start switch 66. As described above, the second arithmetic unit 67 periodically sends out a pulse output that increases or decreases the contents of the first register/decoder 68 depending on the polarity and magnitude of the input signal. In this example, it is assumed that the blade 51 is displaced upward in FIG. 3, so the first displacement detector 41. The first subtractor 62 outputs a (+) sign with a large absolute value, and the second displacement detector 42 and the second subtractor 64 output a (+) sign with a small absolute value. These re-outputs are input to the first computing unit 65 to calculate the direction in which the blade 51 has been displaced and the maximum value of the displacement. Sends out an output signal proportional to the value.

The output signal from the first computing unit 65 is transmitted to the second computing unit 67 via the first control start switch 66. The second arithmetic unit 67 sends out pulses to be stored in the first register/decoder 68 in accordance with the absolute value and polarity of the input signal. Since the polarity of the input signal to the second arithmetic unit 67 is positive, the output pulse from the second arithmetic unit 67 is as follows.

The contents of the first register/decoder 68 are output so as to be integrated in the positive direction.

The first register/decoder 68 stores this input pulse in the register 68, and via the decoder 68, the actual displacement compensation rotation speed command value of the drive motor 59 for correcting the displacement of the blade 51 to zero is determined by the motor. A command is transmitted to the drive controller 74 to accelerate the drive motor 59,
As a result, the rotational speed of the main shaft 54 increases, and the centrifugal force of the disk 53 increases, causing the blade 51 to move downward in the figure, that is, when the blade 51 is in the first position. Separate from the second displacement detectors 41, 42, the cutting edge 52 of the blade 51 is controlled to always maintain the position of the displacement amount.

- the blade 51 is in the downward direction in FIG. 3, i.e.

In the case of displacement in the direction approaching the main axis 54, the output signals from the first and second displacement detectors 41.42 and the first and second dividers 62.64 both have a (-) sign, This is input to the first arithmetic unit 65, and an output signal having a (-) sign and proportional to the maximum displacement value is outputted from the first arithmetic unit 65. This signal is transmitted to the second computing unit 67 via the first control start switch 66. The second arithmetic unit 67 sends a negative pulse to the first register/decoder 68 in the direction of decreasing its stored content. As a result, the value of the actual displacement compensation rotation speed stored in the first register/decoder 68 is decreased, and a command to decelerate the blade drive motor 59 is transmitted to the motor drive controller 74.

As a result, the main shaft 54 decelerates, the centripetal force of the disk 53 decreases, and the blade 51 moves upward in FIG.

That is, it is controlled in a direction away from the main shaft 54.

Further, in this example, a comparator 69 is connected to the register side of the first register/decoder 68.

This is based on the fact that the bending of the blade 51 increases when the cutting edge 52 of the blade 5''1- becomes clogged or wear and drop of abrasive grains increase. This is a circuit that detects and commands a dress R start signal 84.

That is, if the cutting edge 52 of the blade 51 becomes clogged, abrasive grains wear out, or fall off, the blade 51 will be displaced (bending).
becomes large, and the value of the actual displacement compensation rotation speed to correct this also becomes large. Since this value is always stored in the first register/decoder 68 during cutting operation, this compensation value can be used to change the value preset in the dressing timing setter 69a to an absolute value in either the positive or negative direction. If the cutting edge 52 exceeds the threshold, it is determined that the cutting blade 52 is clogged, worn, or has fallen off, and a dressing start signal 84 is output.

In this way, in this example, since the dressing time is automatically determined, the efficiency of one operation is significantly improved and unmanned operation is possible.

Note that the displacement detection means 90 uses the first method for detecting a more precise amount of displacement in order to obtain more accurate machining results. Apart from the second displacement detectors 41 and 42, a plurality of other displacement detectors 41' and 42' are arranged at target positions of the cutting site of the silicon ingot 34, and both displacement detectors 41' and 42'
1.42, calculate the maximum displacement of the blade 51 at the central position of the cutting part, and
The actual value at the center position of the cutting part can be determined by calculating the average value or maximum value of the displacement amount calculated from the re-detected value of 2 and the re-detected value of both displacement detectors 41° and 42°. The amount of displacement may also be calculated.

Furthermore, the actual displacement calculation means 91 calculates the actual displacement amount at the center position of the cutting part, and the actual displacement compensation calculation means 92 performs compensation calculation so that the calculated actual displacement amount becomes zero. As shown in FIG. 3 (b), the actual displacement calculation means 9
1 and the actual displacement compensation calculation means 92, the target displacement calculation means 9
1° is set.

By setting a target displacement value and inputting the difference between the displacement target value 86 and the actual displacement amount calculated by the actual displacement calculation means 91 to the actual displacement compensation calculation means 92, the displacement target value 86 is set.
In other words, the cutting locus of the cutting edge 52 of the blade 51 is controlled to match the required target value so that the difference between By correspondingly gradually changing the displacement target value 86, silicon wafers having an arbitrary warped shape can be produced.

It goes without saying that this invention is not limited to the configuration of the above-described embodiment, and can be modified in nine different ways without departing from the gist of the invention. , also in various types of slicing machines with moving blades.

It can be applied.

[Effects of the Invention] As described in detail above, the slicing machine according to the present invention includes an annular cutting tool having a cutting edge on the inner peripheral edge, the cutting tool being attached and supported so that it can be driven one rotation, and the slicing machine according to the invention having a rotation speed of one rotation. A rotating body supported so as to be displaced along the rotational axis direction using centrifugal force according to the rotational force is disposed near the cutting tool and the object to be cut, and at a predetermined interval.

A plurality of tool displacement detection means detect the displacement of the cutting tool during cutting, and from the amount of displacement detected by the detection means, the maximum displacement of the center part of the cut part of the workpiece being cut with the aforementioned cutting tool is determined. The displacement of the cutting tool is controlled by an actual displacement calculation means for calculating the value and a control means for automatically controlling the rotation speed of the rotating body so that the actual maximum displacement amount calculated by the actual displacement calculation means is zero. It is characterized by being controlled to zero.

Further, a method for controlling a slicing machine according to the present invention includes a cutting blade having a cutting blade on an inner peripheral edge of a rotary body supported so as to be capable of driving one rotation, and supported so as to be displaced along the rotational axis direction according to the number of rotations. The amount of displacement of the tool along the rotational axis direction when cutting the object to be cut is measured near the object to be cut and further,
Displacement detection means consisting of displacement detectors arranged at predetermined intervals detects at multiple positions and calculates the direction of displacement and the maximum displacement at the cutting center of the workpiece from the detected values of one car,
So that this maximum actual displacement value is zero.

It is characterized in that the rotation speed of the rotating body is feedback-controlled. Therefore, the present invention provides a slicing machine that has a simple configuration and can improve the surface accuracy of the machined surface of a workpiece at low cost.

Also, a method for controlling the same can be provided.

Further, in the slicing machine according to the present invention, the position of the cutting tool before starting cutting is detected from the displacement signal of one of the displacement detectors, and the rotation speed of the rotary body is controlled so that this position is always maintained at a constant position. .

It has a function to prevent the slice thickness of the object to be cut from changing due to thermal displacement due to temperature rise of the main shaft, etc. Therefore, wafers with uniform thickness can be produced and the quality can be significantly improved.

Further, in the slicing machine according to the present invention, the maximum displacement amount of the rotating body calculated by the actual displacement calculation means is stored as an actual displacement rotation speed compensation value by the actual displacement compensation calculation means,
By equipping a dressing time detection means that commands a dressing start signal for the cutting tool when this value exceeds a predetermined range, the dressing time for the cutting tool is automatically commanded, thereby significantly improving work efficiency. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view schematically showing the configuration of an embodiment of the slicing machine of the present invention, and FIGS. 2 (a) and (b) show the relationship between the displacement of the blade during cutting and the arrangement of the displacement detector. A local action explanatory diagram that schematically explains, and a third
Figures (a) and (b) are block diagrams showing the configuration of a control system of the slicing machine shown in FIG. 1. In the figure, 10... slicing machine, 11... base. 12... Ball screw for cutting feed, 13... Servo motor for cutting feed, 13a... Drive shaft, 14... Cutting feed slide, 21... Slide column, 22...
Pole nut for cutting feed, 23... Ball screw for indexing feed, 24... Servo motor for indexing feed, 24a
... Drive shaft, 25 ... Index feed guide, 31 ...
・Pole nut for indexing feed, 32... Indexing base, 3
3... Ingot mounting base, 34... Silicon ingot (workpiece), 35... Indexing feed mechanism, 41...
. . . First blade displacement ffl"4-1° . . . Another first blade displacement detector provided at a symmetrical position of the cutting site of 41, 42 . . . Second blade displacement detector, 42'・
...Another second displacement detector provided at a symmetrical position of the cutting site 42, 51...Ingot cutting blade (cutting tool), 52...Cutting edge of the blade, 53...Tension disk ( Rotating body), 54: Main shaft, 55: Main shaft mechanism, 56: Driven pulley, 57: Endless belt, 58: Drive pulley, 59: Main shaft drive motor, 59a... Drive shaft, 61... first initial value storage device. 62... First subtractor, 63... Second initial value storage device, 64... Second subtractor, 65... First arithmetic unit. 65a... Compensation coefficient setter, 65°... Third subtractor, 66... First control start switch, 67... Second arithmetic unit, 68... First register/ Decoder, 6
9... Comparator, 69a... Dress time setting device, 71
. . . second control start switch, 72 . . . third computing unit. 73... Second register/decoder, 73a... Reference rotation speed setter, 74... Motor drive controller (tool rotation speed control means), 81... Memory start command, 82...
Rotation speed setting command, 83...Zero detection signal, 84...
Dressing start signal, 86... Displacement target value input signal, 90
... Displacement detection means, 91 ... Actual displacement calculation means, 91
°...Target displacement calculation means, 92...Actual displacement compensation calculation means. 93... Thermal displacement compensation calculation means, 94... Reference rotation speed setting means, 95... Tool rotation speed control means, 96...
Dress time detection means. Part 3 [2 (a) Patent applicant: International Trade and Industry Research Co., Ltd. Figure 3 (b)

Claims (5)

[Claims] (1) An annular cutting tool with a cutting edge on the inner periphery, this cutting tool is attached and supported so that it can be rotated, and the mounting surface position of the cutting tool is adjusted depending on the rotation speed by the centrifugal force caused by the rotation. , a rotating body supported to be displaced along the rotational axis direction, and a plurality of rotating bodies arranged at predetermined intervals near the cutting position of the cutting tool, and before the cutting start of the cutting surface position of the cutting tool. and a displacement detection means constituted by a displacement detector that detects the amount of displacement during cutting, and an actual displacement calculation means that calculates the maximum displacement at the center position of the cutting surface based on the detected displacement detected by the detection means. , an actual displacement compensation calculation means for calculating an actual displacement compensation rotation speed of the rotating body such that the calculated actual displacement becomes zero, and an actual displacement compensation rotation speed command calculated by the compensation calculation means to calculate the rotation speed A slicing machine characterized by comprising a tool rotation speed control means for correcting the rotation speed of the slicing machine. (2) An annular cutting tool having a cutting blade on the inner circumferential edge, which is supported on a rotating body that is rotatably supported so as to be displaced along the rotational axis direction according to the rotational speed, is used when cutting the object to be cut. The amount of displacement in the direction of the rotation axis is detected by a displacement detection means consisting of a plurality of displacement detectors arranged at a predetermined interval near the cutting part of the cutting tool, and from this displacement detection value. A maximum displacement amount of the cutting center position of the cutting tool is calculated by the actual displacement calculation means, and the actual displacement compensation calculation means calculates the actual displacement compensation rotation speed of the rotating body so that the actual displacement amount becomes zero, A method for controlling a slicing machine, comprising controlling the rotation speed of the rotating body. (3) An annular cutting tool having a cutting edge on the inner peripheral edge is supported on the rotating body supported so as to be rotationally drivable so as to be displaced along the rotation axis direction according to the rotation speed, and the cutting tool is The temperature of the rotating body is adjusted so that the position of the cutting part before the start of cutting is such that the amount of displacement detected by one of the displacement detectors, which detects the amount of thermal displacement caused by thermal expansion due to the temperature rise of the rotating shaft, is zero. thermal displacement compensation calculation means for calculating a displacement compensation rotation speed;
2. The slicing machine according to claim 1, further comprising tool rotational speed control means for correcting the rotational speed of said rotating body using the thermal displacement compensation rotational speed calculated by said thermal displacement compensation calculation means. (4) The actual displacement calculated by the actual displacement calculation means is
2. The slicing machine according to claim 1, further comprising dressing timing detection means for issuing a dressing command for the cutting tool when a predetermined displacement amount limit is exceeded. (5) The configuration of both compensation calculation means for zeroing out the actual displacement calculated by the actual displacement calculation means and the thermal displacement detected by one of the displacement detectors is based on a displacement input signal. The second and third arithmetic units send out the number of output pulses and the addition/subtraction code at a set period according to the absolute value of A compensating rotation speed command is sent to the tool rotation speed control means for correcting the rotation speed of the rotating body, which constantly connects the registers in the first and second registers/decoders that perform accumulation addition and subtraction, and the contents of the registers. 2. The slicing machine according to claim 1, further comprising a decoder that outputs .