JPH07148731A - Cutting device of slicing machine - Google Patents

Abstract

PURPOSE:To execute highly accurate work by a method wherein a crystal ingot is cut under the condition that the rigidity of an internal peripheral blade is enhanced. CONSTITUTION:In a slicing machine, in which a crystal ingot 20 is cut in wafer with the internal peripheral blade 16 of a doughnut-like blade 14, the cutting part of the blade 14 is axially displaced by applying axial force to the cutting part of the blade 14 in advance before the start of cutting. Under the state that the cutting part of the deplaced blade 14 is taken as the reference position, the crystal ingot 20 is cut under the condition that the rigidity of the internal peripheral blade 16 is enhanced. Thus, a wafer is cut at high accuracy from the crystal ingot 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slicing machine cutting device, and more particularly to a slicing machine cutting device for manufacturing semiconductor wafers by cutting a semiconductor ingot into thin pieces.

[0002]

2. Description of the Related Art In a slicing machine, an inner peripheral blade or an outer peripheral blade is rotated at high speed and pressed against a semiconductor ingot to manufacture a semiconductor wafer. in this case,
Considering the yield of semiconductor wafers and post-processing, it is advantageous to minimize the displacement of the blade during cutting and reduce the warp of the wafer.

However, due to the tendency of the diameter of semiconductor wafers to increase, the diameter of the blades also increases, which makes the cutting position of the blades unstable during cutting, resulting in uneven blade shapes, clogging, and surface tension of cutting fluid. The surface of the cut work piece tends to warp due to changes in cutting resistance. Under these circumstances, various measures have conventionally been taken to prevent warpage that occurs when the rotary blade is cut.

That is, in Japanese Unexamined Patent Publication No. Sho 61-98513, air nozzles are provided on both sides of the blade surface and blade sensors are provided in the vicinity of the air nozzles, and the blade position in the unloaded state of the blade is set to the zero position, and Detects the displacement amount and the displacement direction of the blade from the zero position of the blade, the air is jetted from the air nozzle to correct the displacement so as to eliminate the displacement, and the displacement of the blade is corrected.

Further, in Japanese Unexamined Patent Publication No. 62-225308, a nozzle for cooling / lubricating water is provided on both sides of the blade surface, and a blade sensor is provided in the vicinity of this nozzle to cause displacement of the blade. Cooling and lubricating water are sprayed from the nozzle to correct the displacement of the blade in the same manner as in the control method of Sho 61-98513. Further, in Japanese Unexamined Patent Publication No. 1-110105, a negative pressure suction type nozzle is provided on both sides of the blade surface and a blade sensor is provided, and when the blade displacement is detected by the blade sensor, the negative pressure suction type on the side opposite to the blade displacement is detected. Air is blown out from the nozzle to generate negative pressure and correct the blade displacement.

Further, in Japanese Utility Model Laid-Open No. 61-122811, a semiconductor ingot or a blade is made movable in the axial direction, and a blade sensor for detecting the axial displacement of the blade is provided.
When the displacement of the blade is detected based on the signal from the blade sensor, the ingot or the blade is moved in the axial direction,
Correct the axial displacement of the blade.

[0007]

In the conventional cutting device for a slicing machine described above, the position of the blade before cutting is set to the zero position, and the displacement (warp) in the + direction or the displacement (warp) in the -direction from this zero position. Is detected by a blade sensor and is corrected by a nozzle or the like so as to return to the zero position. However, the inner peripheral blade has its outer peripheral edge pulled up to generate tension, and the rigidity of the vicinity of the inner peripheral blade is weaker than that of the outer peripheral edge. Therefore, warping is likely to occur even if the wafer is cut in a state where the rigidity is weak, and since the rigidity is weak, the warping cannot be sufficiently corrected, and the processing accuracy required for the wafer is difficult to obtain.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a cutting device for a slicing machine which has sufficient rigidity near the inner peripheral edge of a blade and can be machined with high precision.

[0009]

In order to achieve the above object, the present invention provides a cutting device of a slicing machine for cutting a crystal ingot into thin flakes with an inner peripheral blade of a donut-shaped rotating blade. Before starting, the cutting portion of the rotary blade is preliminarily provided with a pressurizing means for axially displacing the cut portion of the rotary blade by applying a force in the axial direction, and is displaced by the force applied in the axial direction by the pressing means It is characterized in that the crystal ingot is cut with the position of the cutting portion of the rotary blade as a reference position.

[0010]

In the present invention, the pressing means preliminarily displaces the cutting portion of the rotating blade by applying an axial force to the vicinity of the inner peripheral edge of the rotating blade, and the position of the displaced cutting portion of the rotating blade is used as the reference position. Cut the crystal ingot. in this case,
Since the rotary blade has been displaced in advance, it has high rigidity and little warpage during cutting, and since the rotary blade has high rigidity, it is easy to control the position of the inner peripheral blade during cutting.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a cutting device for a slicing machine according to the present invention will be described below in detail with reference to the accompanying drawings.
In FIG. 1, a chuck body 12 is fixed to the upper end of the spindle 10, and a motor (not shown) is connected to the lower end of the spindle 10 so that the spindle 10 and the chuck body 12 can rotate. Has become. An outer peripheral edge of a donut-shaped blade 14 is pulled up on the chuck body 12, and an inner peripheral blade 16 is formed on the inner peripheral edge of the blade 14. The inner peripheral blade 16 is composed of fine diamond abrasive grains or the like. The outer peripheral edge of the blade 14 can be adjusted in tension by a well-known tensioning mechanism (not shown) of the chuck body 12.

The upper end of the semiconductor ingot 20 is fixed to the lower surface of the work support base 18. The work supporting table 18 can be moved in a cutting feeding direction (XX direction) by a cutting feeding mechanism 22. Further, the work supporting table 18 is moved by a work indexing mechanism 24 in a work indexing direction (Z-Z direction). ) Can be moved to. The cutting feed mechanism 22 and the work indexing mechanism 24 are driven by a command signal from a control device 26. Further, a pair of air pads 28, 28 are arranged on the upper surface of the blade 14 as shown in FIG. Further, a pair of non-contact type blade sensors 30, 30 are arranged in proximity to the air pads 28, 28. This air pad 2
8, 28 blade sensors 30, 30 are arranged so as to be positioned on both sides of the ingot 20 being cut, as shown in FIG. 2, and the air pads 28, blade sensors 30 are positioned near the inner peripheral blade 16 of the blade 14. It is located in. Therefore, when air is ejected from the air pads 28, 28, the inner peripheral blade 16 of the blade 14 bends downward as shown in FIG.

The air pads 28, 28 are connected to the air pressure adjusting device 32 shown in FIG.
Are controlled by command signals from the controller 26. The signals from the blade sensors 30 and 30 are transmitted to the control device 26.
The control device 26 can adjust the air pressure adjusting device 32 based on this signal. The cutting of the ingot by the cutting device of the slicing machine according to the present invention configured as described above is performed as follows. First, the blade 14 is stretched with a predetermined tension by the blade tensioning mechanism of the chuck body 12. However, since the blade 14 is pulled up by applying pressure to the outer peripheral edge of the blade 14, the rigidity in the vicinity of the inner peripheral blade 16 is smaller than that of the outer peripheral side of the blade 14, and the rigidity is sufficient to obtain the accuracy required for the wafer. It is empirically known that it is not. Therefore, in the conventional cutting device, a warp occurs during cutting, and an air nozzle or the like is provided to correct the warp, but the position of the inner peripheral blade cannot be controlled sufficiently. In the invention of the present application, air having a predetermined pressure is ejected from the air pads 28, 28 after the blade is stretched and before cutting. This causes the blade 14 to bend downward as shown in FIG. In this state, sufficient rigidity is given near the inner peripheral blade 16 of the blade 14,
Cutting is started with the position bent downward as a reference position. The position of the blade 14 at this time is determined by the blade sensor 3
0 and 30 are detected and the control device 26 stores them.

In this state, the cutting feed mechanism 22 is operated to move the work support base 18 toward the inner peripheral blade 16. When cutting in this state, sufficient rigidity is given to the inner peripheral blade 16, the cutting position of the blade is stable, and displacement of the inner peripheral blade 16 due to surface tension or the like can be reduced as compared with the conventional case. it can. That is, in this state, the blade 14 is inclined and surface tension is unlikely to occur. When the warp occurs, the position of the inner peripheral blade 16 is detected by the blade sensors 30 and 30, and the air pressure adjusting device 32 is controlled so as to return to the stored reference position. This control is also performed accurately because the rigidity of the blade 14 is high.

In the above embodiment, the air pressure adjusting device 32 is used to adjust the air pressure ejected from the air pads 28, 28, but the present invention is not limited to this, and the air pressure adjusting device 50 shown in FIG. 5, FIG. 6 or FIG. , 52 or 54 may be used. Hereinafter, based on FIG. 5, FIG. 6 or FIG.
0, 52, or 54 will be described. The same members as those in the above embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The beam 56 of the air pressure adjusting device 50 is a leaf spring 5.
A slicing machine main body 60 is cantilevered via 8 and a weight 62 is movably provided on the beam 56. A shaft 64 is screwed to the weight 62, and the shaft 64 is coaxially connected to a rotation shaft 66A of a motor 66. The motor 66 is fixed to the right end of the beam 56.
An air pad 28 is provided at the left end of the beam 56. If the weight of the weight 62 is P1 and the weight of the weight 62 acting on the air pad 28 is P2, the relationship of P2 = (L1 / L2) P1 is established between P1 and P2.

In the air pressure adjusting device 50, when the motor 66 is rotated, the weight 62 moves along the beam 56 in the direction of arrow AB. Therefore, when the weight 62 is moved in the direction of the arrow A, L1 increases, so the value of P2 increases from the relationship of P2 = (L1 / L2) P1, and the beam 56 counterclockwise against the biasing force of the leaf spring 58. Rotate in the direction. As a result, the air pad 28 approaches the blade 14 (that is, the gap between the air pad 28 and the blade 14 decreases), so that the pressure of the air ejected from the air pad 28 to the blade 14 increases, and the blade 14 bends further downward. Sufficient rigidity is given.

When the weight 62 is moved in the direction of arrow B, L
Since 1 becomes smaller, the value of P2 becomes smaller, and the gap between the air pad 28 and the blade 14 becomes larger. Therefore, the pressure of the air jetted from the air pad 28 to the blade 14 becomes low. In this way, the air pressure adjusting device 50 can adjust the rigidity of the blade 14 by moving the weight 62.
In FIG. 5, reference numeral 68 is a bearing that rotatably supports the shaft 64.

In the air pressure adjusting device 52 of FIG. 6, the beam 56 is cantilevered by the slicing machine main body 60 via the leaf spring 58, and the weight 62 is movably provided on the beam 56. It is the same as the adjusting device 50. The air pressure adjusting device 52 is different from the air pressure adjusting device 50 in that the weight 62 moves on the belt 70. That is, the weight 62 is connected to the endless belt 70, and the belt 70 is connected to the pulleys 70, 7.
It is stretched to 2. The pulleys 72 and 74 are rotatably supported by the beam 56 at a predetermined interval, and a motor 76 is connected to the pulley 74 so as to transmit a rotational force. Therefore, when the motor 76 is driven, the weight 62 moves the beam 5 via the belt 70.
Move along arrow 6 in the direction of arrow AB. Therefore, the air pressure adjusting device 52 can adjust the rigidity of the blade 14 by moving the weight 62 similarly to the air pressure adjusting device 50.

The beam 8 of the air pressure adjusting device 54 shown in FIG.
In No. 0, the right end is cantilevered by the slicing machine main body 60, and the air pad moving mechanism (for example, piezoelectric element) 82 is provided at the left end. An air pad 28 is provided on the piezoelectric element 82. Therefore, when a voltage is applied to the piezoelectric element 82, the piezoelectric element operates and the air pad 28 moves vertically. As a result, the air pressure adjusting device 54 can adjust the air pressure of the blade 14 by the movement of the air pad 28 like the air pressure adjusting devices 50 and 52, and adjust the rigidity of the blade 14.

Further, as shown in FIG. 4, only one air pad 28 may be provided and the blade may be inclined and cut. Although the air pad 28 is provided on only one side of the blade 14 in the above embodiment, it may be provided on both side surfaces. In the above embodiment, the blade is bent by air pressure, but fluid pressure may be used, or another axial pressing means can be used.

In the above embodiment, the air pressure adjusting device 32 is controlled so that the blade 14 is returned to the reference position. However, the present invention is not limited to this. A wafer shape curve) may be input to the control device 26, and the air pressure adjusting device 32 may be controlled along the cutting curve to perform cutting. Even in this case, the blade 14 has a higher rigidity than that of the conventional blade, and therefore a wafer having a shape closer to the ideal cutting curve is cut.

[0023]

As described above, according to the cutting device of the slicing machine of the present invention, the cutting portion of the inner peripheral blade is displaced in advance to increase the rigidity, and the displaced cutting position of the rotating blade is set as the reference position. To cut the wafer. Therefore, it is possible to perform cutting with higher rigidity of the inner peripheral blade as compared with the conventional cutting device, and thus it is possible to perform highly accurate processing.

[Brief description of drawings]

FIG. 1 is a schematic view of a cutting device of a slicing machine according to the present invention.

FIG. 2 is a plan view showing a main part of a cutting device of a slicing machine according to the present invention as viewed from above.

3 is a cross-sectional view taken along the line AA in FIG.

FIG. 4 is a cross-sectional view taken along the line AA in FIG. 2 in the case where there is one air pad.

FIG. 5 is a side view showing another embodiment of the air pressure adjusting device used in the cutting device of the slicing machine according to the present invention.

FIG. 6 is a side view showing a modified example of FIG.

FIG. 7 is a side view showing another modification of FIG.

[Explanation of symbols]

 14 ... Blade 16 ... Inner peripheral blade 20 ... Ingot 26 ... Control device 28 ... Air pad 30 ... Blade sensor

Claims (9)

[Claims] 1. A cutting device of a slicing machine for cutting a crystal ingot into thin flakes with an inner peripheral blade of a donut-shaped rotating blade, wherein an axial force is applied to a cutting portion of the rotating blade in advance before starting the cutting. In addition, it comprises a pressing means for axially displacing the cutting part of the rotary blade, and cutting the crystal ingot with the position of the cutting part of the rotary blade displaced by the force applied in the axial direction by the pressing means as a reference position. A cutting device for a slicing machine, which is characterized by performing. 2. The pressurizing means is provided with an air pad, the force applied in the axial direction is generated by the air pressure blown from the air pad, and the position of the rotary blade is controlled by the air pressure. Item 1. A cutting device for a slicing machine according to item 1. 3. The pressurizing means changes the pressure of air blown from the air pad to change the force applied in the axial direction to displace the rotary blade to a desired position in the axial direction. The cutting device for a slicing machine according to claim 2. 4. The slicing machine according to claim 3, wherein the pressurizing means adjusts the pressure of the air blown out from the air pad by an air pressure adjusting means to change the force applied in the axial direction. Cutting device. 5. The pressurizing means maintains the air pressure of the air pad constant, and changes the gap between the air pad and the rotating blade to change the force applied in the axial direction. 2 slicing machine cutting device. 6. The pressurizing means provides the air pad at the tip of a cantilever beam supported by a slicing machine body via a leaf spring, and the change in the gap between the air pad and the rotary blade is along the cantilever beam. The cutting device for a slicing machine according to claim 5, wherein the weight is moved. 7. The pressing means is provided with the air pad at the tip of a cantilever supported by a slicing machine body via an air pad drive mechanism, and the air pad drive mechanism moves the air pad forward and backward with respect to a rotary blade. The cutting device for a slicing machine according to claim 5, wherein a gap between the air pad and the rotary blade is changed. 8. The rotating blade during cutting is equipped with a blade sensor for detecting the axial displacement of the rotating blade, and the displacement sensor detects the displacement position of the rotating blade before the start of cutting to be a reference position. The cutting device for a slicing machine according to claim 2, wherein the position of the rotary blade is controlled so that the blade is located at the reference position. 9. The cutting device for a slicing machine according to claim 2, wherein the pressing means controls the position of the rotary blade so as to follow a predetermined cutting curve.