JPH08276421A - Method and apparatus for controlling to cut in slicing machine - Google Patents

Abstract

PURPOSE: To provide a method and an apparatus for controlling to cut in a slicing machine in which a low-cost wafer having an excellent flat surface accuracy is obtained and which can easily deal with the existing slicing machine without reducing the working efficiency. CONSTITUTION: The feeding speed of a moving table 4 is so previously set as a curve (control reference curve S) with respect to the rotating speed of a blade 14 as to stabilize the cutting resistance, the rotating speed is always detected, the feeding speed optimum for the detected speed is calculated from the curves S, and the table 4 is driven at the speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ingot cutting control method for a slicing machine and an improvement of the apparatus.

[0002]

2. Description of the Related Art A slicing machine brings an ingot of silicon or the like, which is a material of a semiconductor element, relatively close to a cutting edge of a rotating thin blade cutting tool (herein referred to as "blade") and has a predetermined thickness. Cut into pieces to produce wafers. The slicing machine includes an inner peripheral blade type cutting machine and an outer peripheral blade type cutting machine. Further, the inner peripheral blade type cutting machine can be classified into a vertical type and a horizontal type depending on the mounting posture of the ingot. FIG.
Figure 1 shows an example of a vertical type inner blade cutting machine (elevation view of the main part).

In FIG. 4, the inner peripheral blade type cutting machine includes a pedestal 1
Moving table 4 on the table guide 2 provided on the upper surface of
Is movably supported in the X direction, and is driven by a built-in drive mechanism. A column 5 is attached to the moving table 4, and a work holder 7 supported by a vertical guide provided on the column 5 so as to be movable in the Z direction is driven by a drive mechanism incorporated in the column 5. Further, a tension head 13 is supported by a rotating mechanism on a processing portion 10 provided next to the table guide 2, and a blade 14 is attached to the tension head 13 by being pulled up by a top ring 15.

In the inner blade cutting machine thus constructed, the moving table 4 is rotated with the blade 14 rotated at a high speed so that the end face of the ingot W is located below the cutting edge 14a of the blade 14 by the thickness of the wafer. The ingot W is moved in the X right direction from the substantially central position of the blade 14 by the so as to cut the ingot W.

In this case, as the cutting progresses, the cutting edge 14a
The cutting resistance increases due to various factors such as abrasion of the slag and accumulation of sludge between the ingot W and the blade 14. Blade 14
Has a low rigidity in the axial direction (Z direction in FIG. 2), and if the cutting resistance increases, the cutting edge 14a of the blade 14 is likely to be displaced in the axial direction from the initial state. Needless to say, the plane accuracy of the wafer depends on the axial accuracy when the blade edge 14a of the blade 14 is cut. Therefore, if the cutting is continued with the cutting resistance increased, a wafer with good plane accuracy cannot be obtained. Further, the blade 14 may be broken in some cases.

In recent years, the diameter of the ingot W has been gradually increased due to the improvement of semiconductor production efficiency, and the axial accuracy required for the blade 14 at the time of cutting has become more and more severe. Therefore, various proposals have been made as cutting control methods.

As one of them, there is "JP-A-3-058804 (operating method of slicing machine)" disclosed by the present applicant. This method utilizes the fact that the rotational speed of the blade 14 decreases as the cutting resistance increases, and the rotational speed of the blade 14 is detected to estimate the cutting resistance, thereby controlling the cutting. That is, when the rotation speed is in the normal range, the cutting feed (the ingot W is fed to the cutting edge 14a of the blade 14 by the moving table 4) is continued, and when the rotation speed is in the abnormal range, the cutting feed is stopped. As a result, it becomes possible to improve the plane accuracy of the wafer. The breakage of the blade 14 can also be prevented.

Another method disclosed is "JP-A-6-262620 (Blade deflection detection method and apparatus for slicing device and blade deflection control device)". In this method, a strain sensor is provided on the mounting portion of the ingot to detect the axial load of the ingot, and thereby the axial displacement of the blade is estimated.
Then, the blade rotation speed and the cutting feed speed are controlled and dressing of the blade is instructed so that the axial displacement of the blade becomes small.

[0009]

However, in the method of "Japanese Patent Laid-Open No. 3-058804", the cutting feed is stopped when the rotation speed falls to an abnormal range, so that the machining efficiency tends to decrease. Further, since the normal range has a width and the cutting is continued as the normal range until the rotation speed decreases to some extent, it is not possible to expect an improvement in the plane accuracy of the wafer by that much.

Further, in the method of "JP-A-6-262620", since the strain sensor is provided at the mounting portion of the ingot,
There is a problem that the device becomes expensive and the existing slicing machine cannot be easily applied.

The present invention has been made in view of such circumstances, and a slicing machine for cutting an ingot by moving a moving table supporting the ingot and a rotating blade relatively close to each other can be inexpensively constructed and has a high plane accuracy. An object of the present invention is to provide a cutting control method for a slicing machine and a device therefor which can obtain a good wafer, and which does not reduce the processing efficiency and can easily be applied to an existing slicing machine.

[0012]

According to the present invention, in order to achieve the above object, a cutting control method for a slicing machine estimates a cutting resistance from a rotation speed of a blade 14, and the cutting resistance increases to increase the rotation speed. When is decreased, the moving speed of the moving table 4 is decreased to stabilize the cutting resistance. That is, the feed speed of the moving table 4 that stabilizes the cutting resistance is set in advance as a function (control reference curve S) with respect to the rotation speed of the blade 14. Then, the rotation speed of the blade 14 is constantly detected, the optimum feed speed for the rotation speed is calculated from the control reference curve S, and the moving table 4 is driven at that feed speed.

Further, the disconnection control device is constructed as follows. (B) The storage unit 21 is provided to store the preset control reference curve S. (B) A rotation speed detector 19 is provided to detect the rotation speed of the blade 14. (C) The rotation speed calculation unit 22 is provided, and the rotation speed of the blade 14 is calculated from the rotation speed detected by the rotation speed detector 19. (D) The table speed command unit 23 is provided, and the optimum feed speed of the moving table 4 for the rotation speed of the blade 14 calculated by the rotation speed calculation unit 22 is calculated from the control reference curve S stored in the storage unit 21. Then, the table drive unit 24 is instructed. (E) The table drive unit 24 is provided, and the moving table 4 is driven according to the speed commanded by the table speed command unit 23.

[0014]

In the cutting control method and apparatus for a slicing machine according to the present invention, the optimum feed rate of the moving table 4 with respect to the rotational speed of the blade 14 is preset and stored in the storage section 21 as the control reference curve S. Next, the rotation speed calculation unit 22 calculates the rotation speed of the blade 14 from the rotation speed of the blade 14 detected by the rotation speed detector 19. When the calculated rotation speed is sent to the table speed command unit 23, the table speed command unit 23 calculates the optimum feed speed for the rotation speed from the control reference curve S stored in the storage unit 21 to drive the table. Instruct the section 24. The table drive unit 24 drives the moving table 4 at the instructed feed speed.

[0015]

1 is a block diagram of an embodiment of a cutting control device for a slicing machine according to the present invention. FIG. 1 schematically shows the inner peripheral blade type cutting machine of FIG. 4 described in the prior art, and shows the rotation drive mechanism of the blade 14, the movement drive mechanism of the moving table 4, etc. and the cutting control device related to the present invention. It is added. Therefore, the same functional parts are designated by the same reference numerals.

In FIG. 1, the inner cutter is a frame 1
A movable table 4 is supported by a table guide 2 provided on the upper surface of the table so as to be movable in the X direction, and a table drive mechanism 3 (motor 3a,
It is driven by the feed screw 3b). Moving table 4
A column 5 is attached to the column 5, and a work holder 7 supported by a vertical guide provided on the column 5 so as to be movable in the Z direction is a Z-axis drive mechanism 6 (motor 6a, feed screw 6b, etc.) provided on the column 5. Driven by.

Further, in the processing section 10, a tension head 13 is fixed to the upper end of a main shaft 12 rotatably supported by a bearing stand 11, and a blade 14 is attached to the tension head 13 by being pulled up by a top ring 15. ing. On the other hand, the pulley 12 is provided below the main shaft 12.
A pulley 16a fixed to the rotary shaft of a motor 16 attached to the bearing base 11 is connected to the pulley 12a and a belt 17. Also, the spindle 12
A rotary plate 18 is fixed to the lower end of the rotary plate 18, and a rotational speed detector 19 for detecting the rotational speed of the rotary plate 18 is attached to the bearing base 11. The rotation speed detector 19 is of an optical type or a magnetic type.

Further, a storage unit 2 that stores a preset control reference curve S as a relation to the cutting control device.
1. From the rotation speed calculation unit 22 that calculates the rotation speed of the blade 14 from the rotation speed of the blade 14 detected by the rotation speed detector 19, from the control reference curve S stored in the storage unit 21,
The table speed command unit 23 and the table speed command unit 23 instruct the table drive unit 24 to calculate the optimum feed speed of the moving table 4 for the rotation speed of the blade 14 calculated by the rotation speed calculation unit 22. A table drive unit 24 that drives the moving table 4 according to the speed is provided.

In the meantime, the inner peripheral blade type cutting machine having the above-mentioned structure operates in the following manner as described in the prior art. That is, when the ingot W is located at the substantially central position of the blade 14, the motor 16 is driven by the control unit (not shown), which causes the blade 14 to rotate at high speed. Next, the Z-axis drive mechanism 6 feeds the ingot W in the Z downward direction so that the end surface of the ingot W is located below the cutting edge 14a of the blade 14 by the thickness of the wafer. From that state, the moving table 4 is moved in the X right direction by the table drive mechanism 3, and the ingot W is cut.

In this case, when the cutting resistance applied to the blade 14 increases, the rotation speed of the motor 16 decreases,
This is shown in FIG. The horizontal axis of FIG. 2 is the cutting resistance R, the vertical axis is the rotation speed Ω, and the characteristic curve is T. As shown in FIG.
In the characteristic curve T, the rotation speed was Ωa when the cutting resistance was Ra, but the rotation speed decreased to Ωb when the cutting resistance increased to Rb.

Further, using this characteristic curve T, the control reference curve S is set as follows. The control reference curve S is shown in FIG. The control reference curve S represents the feed speed of the moving table 4 that stabilizes the cutting resistance as a curve with respect to the rotation speed of the blade 14. That is, the rotational speed Ω for the cutting resistance R obtained from the characteristic curve T of FIG. 2 is used, and the horizontal axis is the rotational speed Ω of the blade 14 instead of the cutting resistance R. The vertical axis represents the feed speed V of the moving table 4. As shown in FIG. 3, this control reference curve S
Then, the feed speed is set to Va when the maximum rotation speed is Ωa (the cutting resistance is Ra), and the feed speed is set to Vb when the cutting resistance is increased to Rb and the rotation speed becomes Ωb.

The cutting control device of the embodiment is configured in this way, the rotation speed of the blade 14 is detected by the rotation speed detector 19, and the rotation speed Ω of the blade 14 is calculated by the rotation speed calculation unit 22 from the data. . The rotation speed Ω calculated by the rotation speed calculation unit 22 is sent to the table speed command unit 23, and the table speed command unit 23 uses the control reference curve S stored in the storage unit 21 to determine the optimum feed speed for the rotation speed. V is calculated and the table drive unit 24 is instructed. The table drive unit 24 drives the motor 3a so that the moving table 4 has the commanded feed speed V.

In the embodiment, the vertical type inner peripheral blade type cutting machine has been described, but the present invention is not limited to this, and the present invention can be applied to a horizontal type inner peripheral blade type cutting machine. Similarly, the present invention can be applied to a peripheral cutting machine.

[0024]

As described above, according to the cutting control method for the slicing machine and the apparatus therefor according to the present invention, the feed speed V of the moving table 4 so that the cutting resistance R is stable.
Is preset as a function (control reference curve S) for the rotation speed Ω of the blade 14, the rotation speed Ω is constantly detected, and the optimum feed speed V for the detected rotation speed Ω is calculated from the control reference curve S, The moving table 4 is driven at the feed speed V.

As a result, since the cutting resistance R is controlled in real time and the cutting resistance R is stabilized, it is possible to obtain a wafer with good plane accuracy and prevent the blade 14 from breaking. Further, even if the cutting resistance increases, the cutting is not interrupted, so that the working efficiency does not decrease. Furthermore, since no special detection device is required and the control method is simple, the structure can be inexpensive and the existing slicing machine can be easily supported.

Therefore, it is possible to provide a cutting control method for a slicing machine and an apparatus therefor which can be manufactured at a low cost to obtain a wafer having a good plane accuracy and which does not reduce the processing efficiency and can easily be applied to an existing slicing machine. You can

[Brief description of drawings]

FIG. 1 is a configuration diagram of a cutting control device according to the present invention.

FIG. 2 is a characteristic curve diagram of cutting resistance and rotation speed.

[Fig. 3] Control reference curve diagram

FIG. 4 is an elevation view of a main part of a general vertical type inner blade cutting machine.

[Explanation of symbols]

 2 ... Table guide 3a ... Motor 3b ... Feed screw 4 ... Moving table 7 ... Work holder W ... Ingot 12 ... Spindle 13 ... Tension head 14 ... Blade 16 ... Motor 18 ... Rotating plate 19 ... Rotation speed detector 21 ... storage unit 22 ... rotation speed calculation unit 23 ... table speed command unit 24 ... table drive unit

Claims (2)

[Claims] 1. A slicing machine for cutting an ingot by bringing a rotating table supporting an ingot and a rotating blade relatively close to each other, wherein an optimum feed speed of the moving table with respect to a rotation speed of the blade is preset and Is stored as a control reference curve, the rotation speed of the blade is detected, the feed speed of the moving table that is optimum for the detected rotation speed of the blade is calculated from the control reference curve, and the moving table is calculated at that feed speed. A method for controlling cutting of a slicing machine, which comprises driving a cutting machine. 2. In a slicing machine for cutting an ingot by bringing a rotating table supporting an ingot and a rotating blade into close proximity to each other, a preset optimum feed rate of the moving table with respect to a rotating speed of the blade is set. A storage unit that stores the control reference curve, a rotation speed detector that detects the rotation speed of the blade, and a rotation speed calculation unit that calculates the rotation speed of the blade from the rotation speed detected by the rotation speed detector, From a control reference curve stored in the storage unit, a table speed command unit that calculates and commands a feed speed of the moving table that is optimum for the rotation speed of the blade calculated by the rotation speed calculation unit, and the table. A table drive unit that drives the moving table according to the speed instructed by the speed command unit, Cutting control apparatus for slicing machine characterized.