JPH0333484B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for cutting hard and brittle materials. The present invention relates to a method for cutting hard and brittle materials by rotating an inner peripheral blade having a blade on the circumferential edge at high speed.

[Conventional technology]

When cutting a thin silicon wafer (thin plate) by cutting a silicon ingot, which is a hard and brittle material, with an inner peripheral blade that is formed into an annular shape and has a blade member on its inner periphery, the circumference The blade is deformed in its axial direction, which causes the cut silicon wafer to warp, and the silicon wafer to be partially chipped or cracked.

In order to prevent this kind of warping of the inner peripheral blade,
No. 48-101082 proposes a method of supplying liquid at a constant pressure to the inner peripheral blade. Also, JP-A-60-
In No. 2310, air nozzles are installed on the inner edge sides of both sides of the inner circumferential blade, and air is blown simultaneously between the inner circumferential blade and the material to be cut and between the inner circumferential blade and the thin plate being cut. A method has been proposed to prevent warping of the inner peripheral blade by adjusting the air pressure of the nozzle.

[Problem that the invention seeks to solve]

According to the former cutting method described above, a large amount of liquid is supplied to the gap between the material to be cut and the inner peripheral blade, and between the thin plate being cut and the inner peripheral blade, and the warpage of the inner peripheral blade increases. This causes the problem that the thin plates crack and scatter.

In addition, according to the latter cutting method, if the inner peripheral blade warps toward the thin plate being cut, increasing the air pressure supplied between the inner peripheral blade and the thin plate to prevent warping, There is a problem in that a large bending force is applied to the thin plate and the thin plate is easily damaged.

Furthermore, if the supplied air pressure is increased to prevent warping, the inner peripheral blade and the air nozzle will easily come into contact, and there is a risk of scratching the stainless steel plate of the internal peripheral blade, causing damage to the internal peripheral blade. It has the disadvantage of being easy to do.

Furthermore, if the amount of displacement of the inner peripheral blade becomes abnormally large during cutting, the operator must judge this and temporarily stop the cutting operation and take measures such as dressing or retensioning the inner peripheral blade. There is a problem that the cutting operation rate of silicon wafers decreases.

[Means for solving problems]

In view of the above-mentioned problems, the present invention has a plurality of nozzles arranged in parallel in the radial direction of the inner circumferential cutter on both sides of the inner circumferential cutter, and gas is ejected from a group of nozzles on either one side or the other side of the inner circumferential cutter. It is an object of the present invention to provide a method for cutting hard and brittle materials that can prevent warping of an inner peripheral blade during cutting and improve productivity and cutting accuracy when cutting a thin plate from a material to be cut.

The method for cutting hard and brittle materials of the present invention involves rotating an inner peripheral blade that is formed in an annular shape and having blades on its inner peripheral edge, and using nozzles provided on both sides of the internal peripheral blade to prevent warping of the internal peripheral blade. In the method for cutting hard and brittle materials, the blade contacts the material to cut the material while jetting fluid, and a plurality of nozzles are provided in the radial direction of the inner peripheral blade on both sides of the inner peripheral blade. , detects the warpage of the rotating inner peripheral blade, and based on the detection result, injects gas only to one side or the other side of the inner peripheral blade from a nozzle group on one side or the other side in order to eliminate the warpage of the internal peripheral blade. It is characterized by cutting by ejecting and applying negative pressure between the inner peripheral blade and the nozzle.

The advantages of using the negative pressure fluid nozzle, that is, the so-called Bernoulli type fluid nozzle, will be further described.

Generally, when operating a circumferential blade, a method of ejecting liquid from a fluid nozzle and using a positive pressure nozzle is also considered. In this case, it is better to set the distance between the positive pressure nozzle and the inner peripheral blade as small as possible for a greater operating effect, but if this distance is made too small, the nozzle and the peripheral blade will come into contact and damage the inner peripheral blade. Increased risk.

On the other hand, when comparing cases where the same nozzle is used, it is important to make the distance between the nozzle and the inner blade larger when the nozzle is operated under negative pressure than when it is operated under positive pressure. It is unique in that it avoids the danger of coming into contact with the blade.

[Effect]

A displacement sensor detects warpage that occurs in the inner peripheral blade during cutting, and provides a detection signal to the warpage control section. The warpage control unit controls gas pressure to be ejected from a group of nozzles arranged in parallel in the radial direction of the inner peripheral blade to one or the other surface of the internal peripheral blade in accordance with the amount of displacement of the warp based on the given detection signal. Control. Due to the pressure of the gas ejected from the nozzle group, negative pressure acts between the inner circumferential blade and each nozzle, and the inner circumferential blade is sucked toward the nozzle that is ejecting gas. The distance between the inner peripheral blade and the nozzle changes in accordance with the increase or decrease in gas pressure.

As a result, the warpage of the inner peripheral blade during cutting is eliminated over the radial direction, and the parallelism of both surfaces of the thin plate cut from the material to be cut is improved. Also, the cut thin plates do not crack or scatter. Furthermore, there is no problem such as the nozzle coming into contact with the inner circumferential cutter and damaging the inner circumferential cutter.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments thereof. FIG. 1 is a front view of a cutting device for applying the method for cutting hard and brittle materials according to the present invention,
An annular inner peripheral blade holder 2 is rotatably attached to the cutting device main body 1 in a vertical position. On the inner circumferential side of this inner circumferential blade holder 2, an annular inner circumferential blade 3 whose outer circumferential side is held between the inner circumferential blade holders 2 is disposed in a stretched manner. The inner peripheral blade 3 consists of an internal peripheral blade main body 3a made of an annular thin plate of stainless steel and a blade member 3b made of a diamond blade provided along the inner peripheral edge of the internal peripheral blade main body 3a. A material to be cut holder 4 is arranged on the inner peripheral side of the inner peripheral blade 3, and a material to be cut 5, which is a hard brittle material such as a cylindrical silicon ingot, is attached to this with its axis in a horizontal state. It's becoming like that. In other words, the inner peripheral blade 3 and the material to be cut 5 can be positioned so that the inner peripheral blade 3 cuts the material to be cut 5 at right angles to the length direction thereof.

The workpiece holder 4 is movable separately in the radial direction and axial direction of the inner peripheral blade 3. Due to these movements, the material to be cut 5 moves as shown by the broken line and is cut, and by moving in the axial direction of the inner peripheral blade 3, the thickness of the thin plate to be cut can be selected. On both sides in the circumferential direction of the inner peripheral blade 3 of the workpiece holder 4, cutting fluid nozzles 6, 6 for spouting cutting fluid are arranged at positions where the internal peripheral blade 3 and the workpiece 5 come into contact. .
On both sides narrowing the movement range (lined part) of the workpiece 5, the inner peripheral blades 3 are arranged at appropriate lengths apart in the radial direction of the inner peripheral blades 3 with their respective length directions in the same direction.
The nozzles 7L, 7L and 7R, 7R that eject air toward the inner circumferential cutter 3 are arranged close to the inner circumferential cutter 3 so as not to come into contact with the workpiece 5. Also the nozzles 7L, 7L, 7
Nozzles 7L, 7L, 7R, facing R, 7R,
7R (see Figure 4) is installed. These nozzles 7L, 7R have a length that is approximately 1/3 of the width of the inner peripheral blade 3, and are formed into a rectangular parallelepiped-shaped box with an air chamber 7e (described later) inside. Also, each nozzle 7
L and 7R are arranged so that their length directions are along the radial direction of the inner peripheral cutter 3. The cutting fluid nozzle 6, 6
Cleaning liquid nozzles 9, 9 are disposed near the inner circumferential edge of the inner circumferential cutter 3, and are disposed on both sides of the inner circumferential cutter 3, respectively. The cleaning liquid spout ports of these cleaning liquid nozzles 9 face each surface of the inner peripheral blade 3, and spray the cleaning liquid in a mist to blow away chips attached to the periphery of the blade member 3b of the internal peripheral blade 3. It's summery.

One nozzle 7L is installed on one side of the inner peripheral blade 3.
and the movement area of the workpiece in the radial direction of the inner peripheral blade 3, and a displacement sensor 8 made of, for example, an eddy current sensor is disposed near the inner peripheral edge of the inner peripheral blade 3. The warpage, that is, the amount of displacement is detected.

Each nozzle 7L is constructed as shown in FIGS. 2 and 3, with FIG. 2 being a sectional view taken along the line -- in FIG. 1, and FIG. 3 being a partial sectional view taken along the line -- in FIG. Each nozzle 7L, 7R is a Bernoulli type nozzle, and as shown in FIG. 2, the nozzles 7L, 7L are opposed to each other with a gap 7a slightly wider than the thickness dimension of the inner peripheral blade 3, and the screw hole 7b is used. It is firmly fixed and attached to a frame (not shown) using bolts. Further, the opposing distances between each nozzle and both surfaces of the inner peripheral blade 3 are selected to be equal to each other.

Note that other nozzles 7 arranged in parallel in the radial direction
L and 7R are similarly arranged.

On each side of the side where the nozzles 7L, 7L are facing, mortar-shaped nozzle holes 7d, 7d whose diameters are reduced in the facing direction are formed at positions separated by an appropriate length in the longitudinal direction of the nozzle 7L. Openings 7c, 7c are provided at the center of the bottom of the nozzle hole 7d. Further, the respective openings 7c of the opposing nozzles 7L, 7L are opposed to each other. This nozzle hole 7d communicates with an air chamber 7e within the nozzle 7L, and the air chamber 7e communicates with an air supply port (not shown).

When air is supplied to the air supply port of the nozzle 7L, the supplied air enters the air chamber 7e, passes through the nozzle hole 7d, and is ejected from the opening 7c, and the ejected air is diffused at the opening 7c. It is ejected toward the surface of the inner peripheral blade 3. When air is ejected to the inner peripheral blade 3, a negative pressure proportional to the pressure of the ejected air acts between the inner peripheral blade 3 and the nozzle 7L, causing the inner peripheral blade 3 to eject air. A suction force acts toward the nozzle 7L side.

FIG. 4 is a block diagram of a control circuit that controls the inner peripheral blade 3 to eliminate warpage, together with the nozzle 7L, and shows a warpage control section 10 that performs calculation control.
The displacement sensor 8 and the cutting operation control unit 11 input the displacement amount of the inner peripheral blade and signals for cutting start and end, respectively, and the inner peripheral blade rotation output each time the inner peripheral blade 3 rotates once. A total of 13 output pulses are input. The warpage control unit 10 outputs a signal corresponding to the warpage of the inner peripheral blade 3 detected by the displacement sensor 8, and a signal corresponding to the warp of the inner peripheral blade 3.
The signal level of the warpage at each point in time when the inner peripheral blade 3 rotates once is obtained, and the signal level of the warp at the time when the inner peripheral blade 3 rotates once is averaged, and based on the processing result, the air pressure is used to eliminate the displacement of the inner peripheral blade 3. Perform the operation to calculate the PID
Proportional valves 12M and 1 control the air pressure using electrical signals and transmit signals based on the calculated air pressure.
It is designed to give 2N. During cutting, this signal is applied only to the proportional valve 12M or 12N connected to the nozzle 7L on the side where the inner peripheral blade 3 and the nozzle 7L are separated from each other more, and the signal is applied to the proportional valve 12M or 12N connected to the nozzle 7L on the side where the inner peripheral blade 3 and the nozzle 7L are separated from each other more. proportional valve 1 during disconnection.
It is arranged not to give signals to 2M and 12N at the same time. Air at a constant pressure is supplied to the proportional valves 12M and 12N from an air tank (not shown), and when the proportional valves 12M and 12N are controlled, air pressure corresponding to the controlled amount is applied to the nozzle on one side of the inner peripheral blade 3. 7L, 7L, 7R, 7R or nozzle 7 on the other side
It is designed to be given equally to L, 7L, 7R, and 7R. Therefore, when the displacement sensor 8 detects the warpage indicated by the arrow in the direction in which the inner peripheral blade 3 separates from the displacement sensor 8, the warpage control unit 10 controls only one proportional valve 12M, and the displacement sensor If a warp in the direction opposite to the arrow in the direction of the approach of the inner peripheral blade 3 to the proportional valve 8 is detected, a signal to control only the other proportional valve 12N is given to the proportional valve 12M or 12N. In addition, when the cutting start signal is given to the warp control part 10 from the cutting operation control part 11, before cutting into the material 5 to be cut, the warp signal of the inner circumferential blade 3 is taken in, averaged, and processed by the air nozzle. The origin position of the inner peripheral cutter 3 before control is determined. Further, the warp control unit 10 controls the cleaning liquid pump 14 to be driven for a predetermined time every time the cutting of one thin plate is completed, and by this control, the cleaning liquid is spouted in the form of a mist from the cleaning liquid nozzle 9. be.

Next, the operation of cutting the material to be cut 5 using the cutting device configured as described above will be explained with reference to FIGS. 1 and 2.

First, the workpiece 5 is attached to the workpiece holder 4. Subsequently, when a rotation switch (not shown) is operated, a drive signal is applied to a drive section for rotating the inner peripheral blade 3. As a result, the inner peripheral blade 3 starts rotating. In order to cut out the workpiece 5 to a required thickness, the workpiece holder 4 is driven to position the workpiece 5. Thereafter, when a cutting switch (not shown) is operated, the cutting operation control section 11 causes the warpage control section 10 to
A drive signal for moving the workpiece holder 4 in the axial direction and radial direction of the inner peripheral blade 3 is given in connection with the cutting command signal and the cutting operation. When the inner peripheral blade 3 is idling, the inner peripheral blade 3 does not warp, so there is no change from the origin position of the signal from the displacement sensor 8, and the opposing nozzles 7L, 7L and 7R,
The pressure of the air ejected by 7R is constant.

Here, the material to be cut 5 is cut by the inner peripheral blade 3 as shown by the broken line.
When the material to be cut 5 is moved to the outer peripheral side of the inner peripheral blade 3
Cutting is started upon contact with the inner circumferential edge of the material 5, and cutting fluid is supplied from the cutting fluid nozzles 6, 6 to that cutting position, and cutting of the material 5 to be cut progresses. In parallel with this cutting operation, as shown in FIG. Captures the quantity signal and performs averaging processing. Then, the inner peripheral blade 3 calculated before cutting the material 5 to be cut
Based on the displacement origin, calculation is performed to calculate the air pressure that should eliminate the warpage of the inner peripheral blade 3 that occurs during cutting. By the way, when the inner peripheral blade 3 is warped, for example, in the arrow direction away from the displacement sensor 8 (see Fig. 4) due to the cutting operation, a signal based on the calculated air pressure is applied only to the proportional valve 12M, and the proportional valve 12
Stop the signal to N. As a result, the proportional valve 12M
As the degree of opening increases, the pressure of the air ejected from the nozzle groups 7L, 7L, 7R, and 7R on the one side where the displacement sensor 8 is disposed increases. The ejected air hits one side of the inner peripheral blade 3 and diffuses along the inner peripheral blade 3. With such air flow, each nozzle group 7
Negative pressure acts between L, 7L, 7R, and 7R and the inner peripheral blade 3, and the inner peripheral blade 3 is attracted to the displacement sensor 8 side, thereby eliminating the warpage.

Next, the control period will be explained. Warpage control section 10
takes in the displacement meter signal, averages it, calculates the necessary air pressure, and sends the control signal to the proportional valves 12M, 12.
In this embodiment, it is desirable that the interval for sending data to N, that is, the control cycle, be 10 seconds or less.

When cutting silicon ingots, the blade rotation speed is generally 15 to 30 revolutions/second, and the ingot cutting speed is generally in the range of 0.4 to 1.2 mm/second. If the control cycle is longer than 10 seconds, it is clear that if warpage occurs within the control cycle, the inner peripheral blade will have cut in a bent state, making it difficult to correct and the warpage accuracy will deteriorate.

Therefore, in the present invention, it is important to detect the deformation of the inner peripheral cutter at an early stage, and to prevent the deformation of the inner peripheral cutter as early as possible while keeping in mind the target warpage accuracy control range.

In this case, the inner peripheral blade 3 has two nozzle groups 7L, 7L and 7R, 7 arranged in parallel in the radial direction.
Since it is attracted by R, the inner peripheral blade 3 eliminates warpage not only on its inner peripheral edge side but also in its radial region. When the displacement sensor 8 no longer detects warpage, the warpage control unit 10 maintains the signal given to the proportional valve 12M in that state, and the pressure of the air ejected by the nozzle groups 7L, 7L and 7R, 7R is is held in an elevated state. Therefore,
The inner peripheral blade 3 cuts the material 5 to be cut without warping.

In such a cutting state, if the inner peripheral blade 3 warps in the direction approaching the displacement sensor 8 (in the direction opposite to the arrow mark), the displacement sensor 8 will detect the warp, and the proportional valve 12M The signal is stopped and a signal is given only to the proportional valve 12N, the opening degree of the proportional valve 12N increases, and the nozzle groups 7L, 7L and 7R, 7R on the side where the displacement sensor 8 is not disposed eject. Air pressure increases.

Then, the nozzle groups 7L, 7L and 7R on the other side where the inner peripheral blade 3 is not provided with the displacement sensor 8,
It is sucked toward the 7R side and the warpage is eliminated in the same way as above.

Figure 6 shows the actual measured displacement at each distance in the radial direction of the inner peripheral blade when suction force is applied by blowing air at a constant pressure (6 kg/cm ² ) from the nozzle groups 7L, 7L and 7R, 7R. The solid line shows the case where air is ejected from the nozzle group on one side, and the broken line shows the case where air is ejected from the nozzle group on the other side. As is clear from this figure, the warp of the inner peripheral cutter 3 can be displaced more greatly as it approaches the inner peripheral edge side. This is inner peripheral blade 3
This is due to the fact that the closer to the outer periphery, the greater the rigidity. Therefore, when air is ejected at the same pressure from the nozzle groups 7L, 7L, 7R, and 7R arranged in parallel in the radial direction of the inner peripheral blade 3, the inner peripheral edge side In this case, a large amount of displacement can be applied, and warpage in the radial region from the inner circumferential edge side to the outer circumferential edge side can be more reliably eliminated.

Figure 7 shows the actual measured displacement of the inner blade relative to the pressure of the air ejected by the nozzle. For example, the stainless steel plate thickness of the inner blade 3 is 0.15 mm.
In this case, if the air pressure is increased to 3 kg/cm ² , the inner peripheral blade 3 will be displaced by about 25 μm. When displacing the inner circumferential cutter 3 in order to eliminate warpage, the required amount is required from only the nozzle groups 7L, 7L, 7R, and 7R provided on one side and the other side of the inner circumferential cutter 3. When an air pressure of 1 is applied to the inner peripheral blade 3, the inner peripheral blade 3 is sucked toward the nozzle that is spouting air. That is, by not controlling the nozzles provided on both surfaces of the inner peripheral blade 3 at the same time, the inner peripheral blade 3 can be easily displaced in a desired axial direction with low air pressure.

In this way, the material to be cut 5 is cut by controlling the warpage of the inner peripheral blade 3, but each time the cutting of one thin plate is completed, the warp control unit 10 drives the cleaning liquid pump 14 for a predetermined period of time. The cleaning liquid is sprayed in a mist form from the cleaning liquid nozzle 9 onto the blade member 3b portion of the inner peripheral blade 3. Then, the chips adhering around the blade member 3b are blown away to prevent the inner peripheral blade 3 from being deformed by the chips when cutting the next thin plate. In addition, the material to be cut 5
When cutting a thin plate from, for example, the cutting time for the material to be cut 5 with a diameter of 150 mmφ is set to 2 minutes or more and 8 minutes or less, and the time for spraying the cleaning liquid after cutting is set to about 3 seconds in this embodiment. No dirt such as chips was observed on the blade 3.

FIG. 8 shows the amount of displacement of the inner circumferential blade 3 during cutting when the material to be cut is cut by the conventional cutting method and when the material is cut by the cutting method of the present invention, with the horizontal axis representing the cutting time of the thin plate and the vertical axis FIG. 3 is a waveform diagram showing the axis in terms of the amount of displacement of the inner peripheral blade 3 at the cutting position. As is clear from this figure, in the conventional cutting method, as shown in Fig. 8a and b, the inner circumferential blade 3 is cut by 30 μm during cutting.
Some degree of warping occurs. On the other hand, nozzle 7L,
7L, 7R, and 7R are provided, and in response to the warpage of the inner circumferential cutter 3, air is ejected only from the nozzle on one side of the inner circumferential cutter 3 to eliminate the warp, as shown in FIG. Inner peripheral blade 3 during cutting as shown in c and d
The warpage is several μm, and the cutting accuracy is significantly improved. In addition, if chips from cutting a thin plate adhere to the inner peripheral blade 3, the inner peripheral blade 3 will be warped by about 10 μm due to the chips, as shown by the broken line in Fig. 8c, just before one thin plate finishes cutting. Although this may occur in some cases, warping due to chips is also eliminated by jetting out the cleaning liquid at the end of cutting.

In other words, the cutting method of the present invention applies suction force in the direction of the nozzle ejecting air to eliminate the warpage of the inner peripheral blade, so no bending force is applied to the thin plate during cutting, and moreover, Since the nozzles are arranged in parallel in the radial direction of the inner peripheral cutter 3, warpage in the radial area of the inner peripheral cutter 3 is reliably eliminated. Even when no cleaning liquid is sprayed, the amount of displacement of the inner peripheral blade 3 is on the order of several micrometers, and the warpage is eliminated. Therefore, the cutting accuracy of thin plates and the yield of cut thin plates can be dramatically improved.

In addition, in this example, two nozzles were arranged in parallel in the radial direction of the inner peripheral blade, but the number is just an example.
It is not limited in any way. Further, although air is ejected from the nozzle, the same effect can be obtained by ejecting gas or other gas.

Furthermore, the nozzle groups 7L, 7L and 7R, 7R,
Although the material to be cut 5 is provided on both sides of the movement area in which it moves in the radial direction of the inner peripheral blade 3, similar nozzles arranged in parallel in the radial direction are arranged at appropriate distances in the circumferential direction of the internal peripheral blade 3. By providing this, it is possible to eliminate warpage in the entire circumferential area of the inner peripheral cutter 3. Furthermore, although the inner peripheral cutter 3 is installed vertically in this embodiment, it goes without saying that the same effect can be obtained even if it is installed horizontally.

In addition, in this example, the case of cutting a silicon ingot with a diameter of 150 mm was explained, but the cutting control cycle can be modified as appropriate depending on the diameter of the inner peripheral blade, the diameter of the material to be cut, hardness, and cutting performance. It is self-evident that it is necessary.

〔Effect of the invention〕

According to the cutting method of the present invention as detailed above,
Since warpage in the radial region of the inner peripheral blade can be completely eliminated, cutting accuracy and productivity when cutting a thin plate from a material to be cut are greatly improved. In addition, the inner peripheral blade is sucked by the negative pressure of the gas ejected from the nozzle and the warpage is eliminated, so no bending force is applied to the thin plate being cut. Since parallelism is obtained, the yield of cut thin plates can be improved and cutting costs can be reduced. Furthermore, since there is no need to perform operations such as dressing or retensioning the inner peripheral blade to prevent the inner peripheral blade from warping, there is no need to interrupt the cutting operation, and the present invention greatly contributes to industry. It is.

[Brief explanation of the drawing]

Fig. 1 is a front view of a cutting device for applying the cutting method for hard and brittle materials according to the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a sectional view taken along the - line in Fig. 2. , FIG. 4 is a block diagram of a control circuit that controls to eliminate warping of the inner peripheral blade, and FIG. 5 is a timing chart when the warpage control section receives the signal from the displacement sensor.
Figure 6 is a graph showing the relationship between the distance from the inner edge of the inner blade and the amount of displacement of the inner blade when suction force is applied at a constant air pressure, and Figure 7 is a graph showing the relationship between the displacement of the inner blade and the nozzle FIG. 8 is a graph showing the relationship between the amount of displacement of the inner peripheral blade and the air pressure, using actual measurements. FIG. It is. 3... Inner peripheral blade, 4... Workpiece holder, 5...
Material to be cut, 6... Cutting fluid nozzle, 7L, 7R...
Nozzle, 8... Displacement sensor, 9... Cleaning liquid nozzle, 10... Warpage control section, 12M, 12N... Proportional valve.

Claims (1)

[Scope of Claims] 1. Rotating an inner peripheral blade which is formed in an annular shape and having blades on its inner peripheral edge, and jetting fluid from nozzles provided on both sides of the internal peripheral blade in order to prevent warping of the internal peripheral blade. In the method for cutting hard and brittle materials in which the blade is brought into contact with the material to cut the material, a plurality of nozzles are provided in the radial direction of the inner peripheral blade on both sides of the inner peripheral blade, and the inner peripheral blade rotates. Detecting the warpage of the peripheral blade, and based on the detection result, blowing gas only to one side or the other side of the inner peripheral blade from a nozzle group on one side or the other side in order to eliminate the warpage of the inner peripheral blade, A method for cutting hard and brittle materials characterized by cutting by applying negative pressure between an inner peripheral blade and a nozzle.