JPH052489B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for cutting hard and brittle materials, and more specifically, for cutting hard and brittle materials such as silicon ingots into an annular shape. This invention relates to a method for cutting hard and brittle materials by rotating an inner peripheral blade having a blade on its inner peripheral edge at high speed.

[Prior art]

When a silicon ingot, which is a hard and brittle material, is cut into a thin silicon wafer by cutting an annular shaped inner blade with a cutting blade on its inner periphery, the inner blade becomes deformed. However, as a result, the cut silicon wafer may be warped, and the silicon wafer may 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-
No. 2310 is equipped with an air nozzle that applies positive pressure (i.e., separation force) between the inner blade and the nozzle on the inner peripheral edge side of both sides of the inner peripheral blade, so that the inner peripheral blade and the material to be cut and the inner A method has been proposed in which air is blown simultaneously between the peripheral blade and the thin plate being cut, and the air pressure of the nozzles on both sides that push the internal blade apart is adjusted to prevent the internal peripheral blade from warping.

[Problem that the invention seeks to solve]

According to the former cutting method described above, unnecessary 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 becomes larger. 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 may act on 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 air nozzle will easily come into contact with each other.
There is a problem that the inner peripheral blade is damaged because the inner peripheral stainless steel plate is scratched.

In view of the above-mentioned problems, the present invention provides a method for cutting hard and brittle materials that can prevent warpage of the inner peripheral blade during cutting and improve productivity and cutting accuracy when cutting a thin plate from a material to be cut. With the goal.

[Means for solving problems]

The method for cutting hard and brittle materials according to the present invention involves rotating an inner peripheral blade which is formed in an annular shape and has a blade on its inner peripheral edge, and also uses nozzles provided on both sides of the internal peripheral blade to prevent the warping of the internal peripheral blade. In a method for cutting hard and brittle materials in which the blade is brought into contact with the material to cut the material while jetting fluid from the material, warpage of the rotating inner peripheral blade is detected, and based on the detection result, the inner peripheral blade is cut. It is characterized by changing the ejection pressure of the gas ejected toward both sides of the nozzle to apply negative pressure between the inner peripheral blade and the nozzle, thereby preventing the inner peripheral blade from warping.

[Effect]

Immediately before the inner blade cuts into the material to be cut, fluid is simultaneously ejected at a predetermined pressure from nozzles installed on both sides of the inner blade, creating negative pressure on both sides of the inner blade. By applying suction force, the rigidity of the inner peripheral blade is increased. When the inner peripheral blade cuts into the material to be cut,
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 increases the pressure of the fluid jetted from the nozzle on either one side of the inner peripheral blade or the other side according to the amount of displacement of the warp and the direction of the warp based on the given detection signal. The pressure of the fluid ejected from the other nozzle is controlled to be lower than that of the other nozzle. The inner peripheral blade is attracted to the side where the pressure of the fluid supplied to the nozzle is high and at a negative pressure corresponding to the pressure difference of the fluid.

In addition, the inner circumferential cutter has a suction force acting on both sides of the inner circumferential cutter to increase its rigidity.

As a result, the warpage of the inner circumferential blade during cutting is eliminated, 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 scatter, chip, or crack.

〔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. This workpiece holder 4 is movable separately in the radial direction and axial direction of the inner peripheral blade 3. By 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 inner peripheral blade 3 and the workpiece 5 come into contact. . Nozzles 7, 7 for jetting air toward the inner circumferential blade 3 are placed on both sides of the movement area (broken line portion) of the workpiece 5 at positions that do not contact the workpiece 5, respectively. A nozzle 7 (see FIG. 4) is also arranged on the opposite side of the inner circumferential cutter 3 so as to face the nozzles 7, 7.
These nozzles 7 have a length approximately equal to the width dimension of the inner peripheral blade 3, and are slightly wider on the outer peripheral side of the inner peripheral blade 3.
It is a battledore-shaped box with an air chamber 7e (described later) provided inside. Further, the nozzle 7 is arranged so that its length direction is along the radial direction of the inner peripheral blade 3.

One nozzle 7 is placed on one side of the inner circumferential 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 7 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 7 is a Bernoulli type nozzle,
As shown in FIG. 2, the nozzles 7 are opposed to each other with a gap 7a wider than the thickness of the inner peripheral blade 3, and are integrally assembled by inserting a bolt (not shown) into a bolt hole 7b. In the gap 7a between the nozzles 7 and 7 facing each other, the inner circumferential side of the inner circumferential blade 3 is positioned deep inside the gap 7a, and is in a non-contact state with the inner circumferential blade 3 (see Fig. 2). (see Fig. 1).
On each side where the nozzles 7, 7 face each other, there are inverted mortar-shaped openings 7c, 7, which widen in the facing direction, at positions separated by an appropriate length in the longitudinal direction of the nozzles 7.
c, and nozzle holes 7d, 7d are provided at the center of the bottom of the opening 7c. Further, the respective openings 7c of the nozzles 7, 7 facing each other face each other. The nozzle hole 7d communicates with an air chamber 7e inside the nozzle, 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 7, the supplied air enters the air chamber 7e and is ejected from the nozzle hole 7d, and the ejected air is diffused at the opening 7c and spreads onto the surface of the inner peripheral blade 3. erupts towards. 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 7, and the inner peripheral blade 3 is sucked toward the nozzle 7 side. The power to do so works.

FIG. 4 is a block diagram of a control circuit that controls the inner peripheral blade 3 to eliminate warpage, together with the nozzle 7. The warp control section 10 that performs calculation control includes a displacement sensor 8 and a cutting operation control section. Eleven signals are respectively input. The warpage control unit 10 obtains a signal of the warpage direction of the inner peripheral blade 3 detected by the displacement sensor 8 and a signal of the displacement amount of the inner peripheral blade 3, and cancels the displacement of the inner peripheral blade 3 based on the displacement amount signal. Performs calculations to calculate air pressure, and outputs a signal based on the calculated air pressure.
The electric signal is applied to the proportional valves 12M and 12N that control the air pressure. 12
A signal is given to increase the fluid pressure only to N. Further, a signal for lowering the fluid pressure is given only to the proportional valve 12N or 12M connected to one nozzle 7 on the side where the inner circumferential blade 3 and the displacement sensor 8 are closer to each other. Further, the warpage control section 10 includes a cutting fluid nozzle 6
The timing of the control signal given to the proportional valves 12M and 12N is controlled so as not to disturb the flow of the cutting fluid that is spouted out.

Fluid at a constant pressure is supplied to the proportional valves 12M and 12N from a pressure tank (not shown), and when the proportional valves 12M and 12N are controlled, fluid pressure corresponding to the controlled amount is applied to both sides of the inner peripheral blade 3. It is designed to be applied to a nozzle 7 provided in the.
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 one of the proportional valves 1.
2M is controlled to increase the pressure of the fluid ejected from the nozzle 7 connected to it, and the other proportional valve 12
N is controlled to lower the pressure of the fluid ejected from the nozzle 7 connected to it, and when the displacement sensor 8 detects that the inner peripheral blade 3 is warping in the opposite direction to the approaching arrow, the other proportional valve A signal is output to control the 12N so as to lower the pressure of the fluid ejected from the nozzle 7 connected thereto.

Note that when a cutting start signal is given to the warpage control section 10 from the cutting operation control section 11, the fluid pressure in each nozzle 7 is adjusted in advance until the inner peripheral blade 3 and the ingot 5 come into contact with each other after a predetermined time period has elapsed. The sliding warping control unit 10 uses the proportional valve 1 to set the set initial value and to equalize the fluid pressure ejected by the opposing nozzles 7, 7.
The control amounts of 2M and 12N are controlled equally.

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. A drive signal is then given to a drive section for rotating the inner peripheral blade 3. As a result, the inner peripheral blade 3 starts rotating. Next, the workpiece holder 4 is driven to cut the workpiece 5 to a required thickness.
position. Thereafter, when a cutting switch (not shown) is operated, the cutting operation control section 11 sends a cutting command signal to the warping control section 10 to move the workpiece holder 4 in the axial direction and radial direction of the inner peripheral blade 3 in relation to the cutting command signal and the cutting operation. A drive signal to be moved is provided. The warpage control unit 10 sends a signal based on a preset initial value of air pressure to the proportional valves 12M and 12 until the inner peripheral blade 3 and the ingot 5 come into contact after a predetermined period of time has elapsed.
The nozzles 7, 7, facing each other and facing each other, eject air with equal fluid pressure. When the inner peripheral blade 3 is idling, no warpage occurs in the internal peripheral blade 3, so there is no change in the signal from the displacement sensor 8, and there is no change in the pressure of the air ejected by the opposing nozzles 7. do not have.

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 circumference side, the material to be cut 5 comes into contact with the inner peripheral edge of the inner peripheral blade 3 and cutting starts, and cutting fluid is supplied to the cutting position and the cutting of the material to be cut 5 progresses. I will do it. By the way, when the inner peripheral blade 3 warps, for example, in the direction of the arrow pointing away from the displacement sensor 8 (see Fig. 4) due to the cutting operation, the displacement sensor 8 detects the warp and outputs a signal corresponding to the amount of displacement. is input to the warp control section 10. Warpage control section 1
0 performs a calculation based on the input displacement amount to calculate the air pressure that should eliminate the warpage. Then, a signal based on the calculated fluid pressure is sent to the proportional valves 12M and 1.
Give 2N. As a result, the opening degree of the proportional valve 12M increases, and the pressure of the fluid ejected from each nozzle 7 on one side where the displacement sensor 8 is disposed increases.
The ejected fluid hits one side of the inner blade 3 and spreads along the inner blade 3, so this flow of fluid creates a negative pressure between the nozzle 7 and the inner blade 3. As a result, the force that attracts the inner peripheral blade 3 toward the displacement sensor 8 side increases, while the opening degree of the proportional valve 12N decreases, causing each nozzle 7 in the direction of the arrow in which the internal peripheral blade 3 moves away.
The pressure of the fluid jetted out decreases, and the negative suction force acting between the nozzle 7 and the inner peripheral blade 3 decreases. As a result, the warpage of the inner peripheral cutter 3 is eliminated. When the displacement sensor 8 no longer detects warpage, the warpage control unit 10 maintains the signals given to the proportional valves 12M and 12N in that state, so the fluid pressure being ejected from the nozzle 7 is maintained. Ru. Therefore, the inner peripheral blade 3 cuts the workpiece 5 without warping. If the inner peripheral blade 3 warps in the direction approaching the displacement sensor 8 (in the direction opposite to the arrow mark) in such a cutting state, the displacement sensor 8 will detect the warp, and the warp control section 10 controls the opening degree of the proportional valve 12M to become smaller, and controls the opening degree of the proportional valve 12N to become larger.

As a result, the inner peripheral blade 3 is attracted to the nozzle 7 side on the other side where the displacement sensor 8 is not disposed, and the warpage is eliminated.

Note that the control mode of the gas injection pressure to be ejected from each nozzle 7, 7 to both sides of the inner circumferential blade 3 includes the above-mentioned control mode in which one or the other is changed to be high and the other or one is low. The injection pressure of the other or one of the injection pressures may be controlled to be lower or higher while maintaining the injection pressure constant.

Figure 5 shows the measured displacement of the inner blade relative to the pressure of the air ejected by the nozzle. For example, when the inner blade 3 has a thickness of 0.15 mm, the air pressure is set to 3 kg/cm ^2. When raised, the inner peripheral blade is displaced by approximately 10μm.

FIG. 6 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, a warp of about 30 μm occurs in the inner peripheral blade 3 during cutting. On the other hand, when negative pressure is applied, nozzles 7 that apply suction force are provided on both sides of the inner peripheral blade 3 to eject fluid at a predetermined pressure, increasing the rigidity of the inner peripheral blade 3. In the cutting method of the present invention, the pressure of the ejected fluid is changed in response to the warp in step 3 to eliminate the warp.
The warpage of the inner peripheral blade 3 during cutting is several micrometers, and cutting accuracy is significantly improved. In other words, in this cutting method, immediately before cutting the material 5 to be cut, fluid is ejected at a predetermined equal pressure from the nozzles 7 provided on both sides of the inner peripheral blade 3, and negative pressure suction is applied to the inner peripheral blade 3 from both sides. At the same time, when cutting the material 5 to be cut, the fluid pressure of the nozzle spouting fluid is adjusted according to the warpage of the inner peripheral blade 3 to adjust the negative pressure suction force. Since the warpage of the peripheral blade 3 is eliminated, bending force is not applied to the thin plate in the middle of cutting, thereby improving cutting accuracy and yield of cut thin plates.

Although air is ejected from the nozzle in this embodiment, the same effect can be obtained by ejecting fluid such as gas.

In addition, the nozzles 7 are provided on both sides of the movement range in which the material to be cut 5 moves in the radial direction of the inner peripheral blade 3, so as to eliminate warpage of the inner peripheral blade 3 in the portion that contacts the material to be cut 5. However, a plurality of nozzles 7 may be disposed at appropriate intervals in the circumferential direction of the inner peripheral blade 3 to eliminate warping of the entire inner peripheral blade 3. Further, in this embodiment, the inner peripheral cutter 3 is installed vertically, but it goes without saying that the same effect can be obtained even if it is installed horizontally.

〔effect〕

As described in detail above, the cutting method of the present invention involves jetting fluid at a predetermined equal pressure from nozzles provided on both sides of the inner blade immediately before the material to be cut comes into contact with the inner peripheral blade. Negative suction force is applied to both sides of the blade to increase the rigidity of the inner blade, and when cutting the material to be cut, the fluid ejection pressure of the nozzle in the direction in which the inner blade approaches is lowered, and the pressure in the direction in which the inner peripheral blade approaches is increased. The suction force is controlled to increase the fluid pressure of the nozzle, and the warpage of the inner peripheral blade is eliminated without applying bending force to the thin plate during cutting, so there is no damage to the cut thin plate and parallelism on both sides is achieved. Cutting accuracy is greatly improved. Therefore, the yield of cut thin plates can be improved and cutting costs can be reduced. In addition, since there is no need to perform tasks such as dressing and retensioning the inner peripheral blade to prevent warping of the inner peripheral blade, the productivity of thin sheets obtained by cutting the material to be cut is increased without the hassle of being forced to interrupt the cutting operation. The present invention greatly contributes to industry, such as by significantly increasing the

[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 the inner peripheral blade to eliminate warping, and Fig. 5 is a graph showing the relationship between the displacement amount of the internal peripheral blade and the pressure of the air ejected from the nozzle using actual measured values. FIG. 6 is a waveform chart showing the warping state of the inner peripheral blade during cutting when cutting by the conventional cutting method and the cutting method of the present invention. 3... Inner peripheral blade, 4... Workpiece holder, 5...
Material to be cut, 7... Nozzle, 8... Displacement sensor, 1
0...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 a blade on its inner peripheral edge, and spouting fluid from nozzles provided on both sides of the internal peripheral blade to prevent warpage thereof. In a method for cutting hard and brittle materials in which the blade is brought into contact with the material while cutting the material, the warpage of the rotating inner peripheral blade is detected, and based on the detection result, the blade is moved toward both sides of the inner peripheral blade. A method for cutting hard and brittle materials characterized by changing the ejection pressure of gas ejected from each nozzle to apply negative pressure between the inner peripheral blade and the nozzle to prevent warping of the inner peripheral blade. . 2. According to claim 1, the gas ejection pressure is such that the gas ejection pressure of the nozzle provided on one side or the other side is high and the gas ejection pressure of the nozzle provided on the other side or one side is low. The described method for cutting hard and brittle materials. 3. Claim 1, wherein the gas ejection pressure is such that the gas ejection pressure of a nozzle provided on one side or the other side is constant, and the gas ejection pressure of a nozzle provided on the other side or one side is changed. The described method for cutting hard and brittle materials.