JPH05104437A - Camber control method in slicing device and its device - Google Patents

Abstract

PURPOSE:To control the camber of a wafer by detecting the existance of the camber at the time of cutting the wafer, and automatically execute the dressing of an inner peripheral blade. CONSTITUTION:A camber control device is provided with a blade displacement detecting means 12, electrodes 13a, 13b severally arranged on the surface and the back side of an inner peripheral blade, a power source device 14 to apply D.C. voltage for electrolytic dressing between both the electrodes and the blade, and a changing over means 15 to change over a current fed from the power source device to either of the electrodes on the surface and the back side of the blade. A dull blade face is judged on the direction of blade displacement, and the changing over means 15 is changed over to the electrode on the side of the dull blade face and the power source device 14 is turned on and off on the quantity of blade displacement by a control device 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a warping control method and apparatus in a slicing device for cutting a work into a certain thickness to cut out a silicon wafer for integrated circuits.

[0002]

2. Description of the Related Art A slicing device rotates a blade having an inner peripheral blade at the edge of a circular opening, while introducing a tip end of a cylindrical work made of a silicon ingot into the opening of the blade to radially move the blade. By moving, the work is cut into a certain thickness and the wafer is cut out. In this slicing device, as shown in FIG. 4, when there is a difference in sharpness between the front side blade surface 5a and the back side blade surface 5b of the inner peripheral blade 5, the wafer 8a is warped when the wafer 8a is cut from the work 8. For example, the front blade surface 5a
When the sharpness is better, the blade 3 is displaced in the direction of the chain double-dashed line A in FIG. If the back blade surface 5b is sharper, 2
The blade 3 is displaced in the direction of the chain line B, and the wafer 8a is warped in the direction in which the wafer 8a becomes thinner. Conventionally, such a wafer 8a
In order to prevent the warpage of the wafer, the product is inspected for the presence of the warp, and if there is a warp, white wafer is applied to the blade surface on the side with poor sharpness when the wafer is cut and dressing is performed manually. It was

[0003]

However, in the warp correction method using the hand dress, the time for applying the white stone and the dress amount are based on empirical values, and the work requires skill and is extremely difficult. was there. The present invention has an object to solve such a problem, detects the presence or absence of a warp at the time of wafer cutting, and a warping control method in a slicing device capable of automatically performing the dressing of the inner peripheral blade to control the warp and the same. The purpose is to provide a device.

[0004]

In order to achieve the above object, a warpage control method according to the present invention is designed to move a work in a radial direction of the blade with respect to an inner peripheral edge of the blade rotating at a high speed. In a slicing device that cuts the wafer by cutting into a thickness, the displacement of the blade is detected directly or indirectly, the blade surface on the side with poor sharpness is determined based on the direction of the blade displacement, and the sharpness A voltage is applied between the electrode facing the blade surface on the bad side and the blade that is the other electrode to electrolytically dress the inner blade, eliminating the difference in sharpness between the front and back blade surfaces of the inner blade. The warp of the wafer is controlled. Further, the warpage control device according to the present invention, in the slicing device, blade displacement detection means for directly or indirectly detecting the blade displacement, electrodes arranged on the front side and the back side of the inner peripheral blade, and the both electrodes. A power supply device for applying a DC voltage for electrolytic dressing between the blade, a switching means for switching the current from the power supply device to either the front side electrode or the back side electrode, and a blade displacement direction from the blade displacement switching means. And a control means for switching the power supply device on and off based on the blade displacement amount while determining the blade surface with poor sharpness based on the above, switching the switching means to the electrode on the blade surface side with poor sharpness. It is a thing.

[0005]

In general, in a slicing machine, if there is a difference in sharpness between the front and back side blade surfaces of the inner peripheral blade, the blade is displaced to the side with better sharpness and the cutting resistance of the work in the blade displacement direction. Will increase. Therefore, in the warpage control method according to the present invention, if the blade displacement is detected or the cutting resistance is detected, the direction of the blade displacement is directly or indirectly detected. Then, based on the direction of the blade displacement, to determine the blade surface of the inner cutting edge of poor sharpness, if a voltage is applied between the electrode and the blade of the poorly sharpened blade surface side, the poorly sharp side The blade surface is electrolytically dressed and the sharpness is restored. As a result, there is no difference in the sharpness between the front blade surface and the back blade surface of the inner peripheral blade, the blade displacement is reduced, and the warp of the wafer is corrected.

Further, in the warpage control device according to the present invention, when the blade displacement detecting means detects the blade displacement directly or indirectly by the cutting resistance, the control device determines the sharpness of the inner peripheral blade based on the direction of the blade displacement. If the blade displacement amount is equal to or larger than the allowable value, the power supply device is turned on. As a result, a DC voltage is applied between the electrode and the blade from the power supply device, the blade surface with poor sharpness is electrolytically dressed, and the sharpness is restored. This eliminates the difference in sharpness between the front side and the back side of the inner peripheral blade, reduces the blade displacement, and corrects the warp of the wafer.

[0007]

Embodiments of the present invention will now be described with reference to the accompanying drawings. FIG. 1 shows a slicing device equipped with a warpage control device according to the present invention. The dish-shaped disc 1 is fixed to the end of the main shaft 2, and the blade 3 is supported by the outer peripheral edge of the disc 1 at its outer peripheral edge. In the center of this blade 3,
The opening 4 (see FIG. 3) is formed, and the inner peripheral blade 5 is provided at the edge of the opening 4. As shown in FIG. 2, the inner peripheral blade 5 is formed by fixing a cutting blade 6 made of diamond with a bond 7 made of metal such as nickel. The blade 3
When the disk 1 is driven to rotate integrally with the main shaft 2,
As shown in FIG. 5, the motor rotates at a high speed in the direction of arrow r.

A cylindrical work 8 made of a silicon ingot or the like is held at its base end by a holding member 10 provided on a feed table 9 so as to be movable back and forth in parallel with the main shaft 2.
By advancing the holding member 10 toward the blade 3, the tip of the work 8 is introduced into the opening 4 of the blade 3 and protrudes to the back side, and the feed table 9 is moved horizontally, so that FIG. As shown in
The wafer is cut out by being fed laterally in the x direction and cut into a predetermined thickness by the inner peripheral blade 5 rotating at a high speed. A carbon-made slice base 11 is adhered to the cut-off side of the work 8 so that the work 8 will not be damaged when cut off.

This slicing device is equipped with a warp control device for controlling the warp of the cut wafer. It comprises a blade displacement detection sensor 12, a pair of electrodes 13a and 13b for electrolytic dressing, a power supply device 14, a changeover switch 15, and a control device 16. As shown in FIG. 3, the blade displacement detection sensor 12 is disposed in the vicinity of the inner peripheral blade 5 on the front side of the blade 3 and at a position where it does not interfere with the movement of the work 8 and in proximity to the blade 3. The blade displacement detection sensor 12 detects the displacement of the blade 3 in the plate thickness direction, that is, the front side and the back side thereof, and outputs a signal corresponding to the displacement.

The position of the blade displacement detection sensor 12 may be arranged near the inner peripheral blade on the back side of the blade 3 and on the movement center line of the work 8, as shown by the broken line in FIG. .. In this case, the wafer passes between the blade displacement detection sensor 12 and the blade 3, but since the wafer is thin, it does not interfere with the blade displacement detection sensor 12. The electrolytic dress electrodes 13a and 13b are the work 8
As shown in FIG. 2, at positions on the side opposite to the cutting position, the inner peripheral blades 5 are arranged close to the front blade surface 5a and the back blade surface 5b, respectively. And these electrodes 13
A coolant injection nozzle 17 is arranged so that the coolant circulates between a and 13b and the inner peripheral blade 5. The + side of the power supply device 14 is connected to the blade 3 and the-side of the power supply device 14 is connected to the electrodes 13a and 13b through the changeover switch 15, and a DC voltage is applied between the blade 3 and the electrodes 13a and 13b. ..

The changeover switch 15 is adapted to switch the current from the power supply device 14 between the electrode 13a and the electrode 13b. The control device 16 comprises a database 18 and a microprocessor 19. The microprocessor 19 compares the signal from the blade displacement detection sensor 12 with the data stored in the database 18 to determine the blade displacement direction and the displacement amount, and if the blade displacement direction is the front side, the back electrode 13b is used. The changeover switch 15 is changed over so that the voltage is applied, and conversely, when the blade displacement direction is the back side, the changeover switch 15 is changed over so that the voltage is applied to the front electrode 13a. Also,
When the blade displacement amount is larger than the reference value stored in the database 18, the control device 16 turns on the power supply device 14 to apply a DC voltage between the blade 3 and the electrodes 13a and 13b.

In the slicing device having the above-mentioned structure, the sharpness of the front side blade surface 5a of the inner peripheral blade 5 becomes worse than that of the back side blade surface 5b due to abrasion or clogging, and the blade 3 is displaced to the back side. It is assumed that the wafer begins to warp. The blade displacement detection sensor 12 directly detects the displacement of the blade 3 and detects a signal corresponding to the displacement. The microprocessor 19 of the control device 16 compares the signal from the blade displacement detection sensor 12 with the data in the database, determines that the blade displacement direction is the back side direction in this example, and determines the sharpness of the front side blade surface 5a. Then, the changeover switch 15 is changed over to the front electrode 13a side. At the same time, the microprocessor 19 determines whether or not the blade displacement amount is within the allowable value based on the signal from the blade displacement detection sensor 12, and when the blade displacement amount exceeds the allowable value, the power supply device. Turn on 14.

As a result, the blade 3 is supplied from the power supply unit 14.
And a DC voltage is applied between the front electrode 13a and the front electrode 13a,
The front side blade surface 5a is electrolytically dressed. That is, the nickel bond 7 on the front side blade surface 5a is ionized and eluted into the coolant, and the blade surface 5a is electrically activated and chips and the like between the blade edges 6 flow out, so that the blade edges 6 project. Is sharpened. As a result, the difference in sharpness between the front side blade surface 5a and the back side blade surface 5b is eliminated, the displacement of the blade 3 is reduced, and the warp of the wafer is corrected. When the displacement amount of the blade 3 becomes equal to or less than the allowable value, the microprocessor 19 turns off the power supply device 14, so that the front blade surface 5a
The electrolytic dress is finished. Contrary to the above example, the sharpness of the back side blade surface 5b becomes poor and the blade 3 is displaced to the front side,
Even if the wafer has a warp in the direction of increasing the thickness, the warp is corrected by the warp control device in the same manner as described above.

In the above embodiment, the displacement of the blade 3 was directly detected by the blade displacement detection sensor 12. However, a cutting resistance detection sensor is provided in the holding member 10 of the work 8 to increase or decrease the cutting resistance due to the displacement of the blade 3. The displacement of the blade 3 may be indirectly detected by the change of In addition, the microprocessor 1 of the control device 16
In No. 9, the power supply device 14 is turned on and off depending on whether or not the blade displacement amount exceeds the allowable value. However, the present invention is not limited to this, and the following various methods can be used for control.

That is, in the first method, the electrolytic dressing time corresponding to the blade displacement amount is set in advance and stored in the database 18, and the electrolytic voltage corresponding to the displacement amount detected by the blade displacement detecting sensor 12 is set. A dressing time is selected, and the power supply device 14 is turned on during the electrolytic dressing time. The second method is that the current value and the dressing time at the time of electrolytic dressing are set in advance corresponding to the blade displacement amount and stored in the database 18, and these are selected according to the actual displacement amount. The resistance in the power supply device 14 is changed so as to reach the current value, and electrolytic dressing is performed for the selected dressing time. As a third method, an on-time ratio per unit time, that is, a duty ratio and a dressing time are set in advance in correspondence with the blade displacement amount and stored in the database 18, and according to the actual blade displacement amount. While selecting the duty ratio and the dressing time and turning on and off the power supply device 14 at the selected duty ratio,
Electrolytic dressing is performed for a selected time.

[0016]

As is apparent from the above description, according to the present invention, the sharp or bad side of the inner peripheral blade is detected by the blade displacement, and the blade surface on the poorly sharp side is automatically detected by the electrolytic dressing. Therefore, the warp can be quickly and accurately controlled without labor, and labor can be saved.

[Brief description of drawings]

FIG. 1 is a block diagram of a slicing device including a warpage control device according to the present invention.

FIG. 2 is a partially enlarged view of FIG.

3 is a cross-sectional view taken along the line I-I of FIG.

FIG. 4 is a cross-sectional view showing a wafer cut state.

[Explanation of symbols]

3 ... Blade, 5 ... Inner peripheral blade, 12 ...
Blade displacement detection sensor, 13a, 13b ... Electrode, 1
4 ... Power supply device, 15 ... Changeover switch,
16 ... Control device.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B28D 1/22 B 7041-3C

Claims (2)

[Claims] Claim: What is claimed is: 1. A slicing device for cutting a workpiece to a constant thickness by moving the workpiece in a radial direction of the blade with respect to an inner peripheral edge of the blade rotating at a high speed, and displacing the blade. Is detected directly or indirectly, to determine the blade surface on the side of poor sharpness based on the direction of the blade displacement, between the blade that is the other electrode and the electrode facing the blade surface on the side of poor sharpness. A method of controlling warpage in a slicing device, characterized in that a voltage is applied to the inner peripheral blade to electrolytically dress the inner peripheral blade to eliminate the difference in sharpness between the front and back blade surfaces of the inner peripheral blade to control the warp of the wafer. 2. In a slicing device in which a workpiece is cut into a certain thickness by moving the workpiece in a radial direction of the blade with respect to an inner peripheral edge of the blade rotating at a high speed to directly cut the blade displacement. Or blade displacement detection means for indirectly detecting, electrodes arranged on the front side and the back side of the inner peripheral blade, a power supply device for applying a DC voltage for electrolytic dressing between the electrodes and the blade, and the power supply. Switching means for switching the current from the device to either the front side electrode or the back side electrode, and determine the blade face with poor sharpness based on the blade displacement direction from the blade displacement switching means, the blade on the poorly sharp side The switching means is switched to the surface side electrode, and a control means for turning on / off the power supply device based on the blade displacement amount is provided. Warpage control device in slicing device.