JP2965087B2 - Cutting method of slicing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

However, as the diameter of semiconductor wafers increases, the blade diameter also increases, and the cutting position of the blade becomes unstable during cutting, resulting in uneven blade shape, clogging, and surface tension of cutting fluid. The surface of the cut workpiece tends to be warped due to a change in cutting resistance or the like. Under such circumstances, various measures have been conventionally taken to prevent warpage that occurs when the rotating blade is cut.

In Japanese Patent Application Laid-Open No. 61-98513, air nozzles are provided on both sides of a blade surface, and a blade sensor is provided in the vicinity of the air nozzle. Detects the displacement amount and displacement direction of the blade from the zero position of the blade, air is injected from an air nozzle to correct the displacement so as to eliminate the displacement, and the displacement of the blade is corrected.

In Japanese Patent Application Laid-Open No. 62-225308, cooling / lubricating water supply nozzles are provided on both sides of a blade surface, and a blade sensor is provided in the vicinity of the nozzle. Cooling / lubricating water is sprayed from the nozzle in the same manner as in the control method of Japanese Patent Application Laid-Open No. 61-98513 to correct the displacement of the blade. Further, in Japanese Patent Application Laid-Open 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 displacement of the blade is detected by the blade sensor, the negative pressure suction type nozzle on the opposite side to the displacement of the blade is provided. Air is blown out from the nozzle to generate a negative pressure to correct the displacement of the blade.

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

[0007]

However, the conventional slicing machine cutting method has the following disadvantages. In FIG. 9, 1 is a blade and 2 is a blade 1.
, 3 is a cylindrical ingot cut by the inner blade 2, 4 is a blade sensor, and 5 is a pressing pad.

In the conventional cutting method for a slicing machine, the displacement of the blade 1 during cutting is detected by a blade sensor 4 and controlled by a pressing means (for example, a pressing pad 5) so as to make the displacement zero. However, in the conventional cutting method, the pressing pad 5 is controlled so as to eliminate the ingot cutting direction shown in FIG. However, the warpage of the blade 1 in the direction orthogonal to the ingot cutting direction shown in FIG. 11, that is, the YY direction depends on the cutting characteristics or rigidity of the blade 1,
The warpage control of the blade 1 in the −Y direction is not actively performed.

Therefore, if the pressing pad 5 is controlled based only on the warpage control of the blade 1 in the XX direction, the warp shape of the wafer is such that the outer peripheral edges Q of the blade 1 in the XX direction are displaced. Although it is controlled to be zero, the central portion of the blade 1 is not controlled and is cut in an upwardly convex shape, so that there is a tendency to cut a wafer having a part of a cylindrical shape as a whole. Also, it is necessary to reduce the warpage in the wafer manufacturing as a performance of the wafer, but if warpage occurs during the wafer processing process after slicing and cutting, a specified warpage is given in advance at the time of slicing and cutting to complete the wafer. Occasionally, high quality wafers with little warpage and high flatness are manufactured. The conventional cutting method does not consider giving a constant warp in advance as described above, and since the control is performed only in the X-X direction of the cutting direction, the bowl-shaped shape required for the warp is used. It is difficult to cut into pieces.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a cutting method for a slicing machine capable of obtaining a wafer having an arbitrary warp shape.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a slicing machine for cutting a crystal ingot into flakes with an inner peripheral blade of a donut-shaped rotating blade. In the meantime, fluid is ejected to the side surface of the blade from a direction perpendicular to the blade to control displacement of the blade in the cutting direction (XX direction), and fluid is ejected to the blade to be orthogonal to the cutting direction of the blade. By controlling the displacement in the direction (Y-Y direction), a wafer having a predetermined warp shape is cut.

[0012]

According to the present invention, cutting is performed by controlling the displacement of the blade in the X-X direction and also controlling the displacement of the blade in the Y-Y direction. This allows the wafer to have a larger warp near the center of the wafer, and eliminates the displacement of the wafer near the periphery of the wafer in the XX direction and the YY direction. Can be done.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a cutting method 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 an upper end of a spindle 10, and a motor (not shown) is connected to a lower end of the spindle 10 so that the spindle 10 and the chuck body 12 rotate. Has become. An outer peripheral edge of a donut-shaped blade 14 is raised on the chuck body 12, and an inner peripheral blade 16 is formed on an inner peripheral edge of the blade 14. The inner peripheral blade 16 is made of fine diamond abrasive grains or the like. The outer peripheral edge of the blade 14 can be adjusted in tension by a known extension mechanism (not shown) of the chuck body 12.

An upper end of a semiconductor ingot 20 is fixed to a lower surface of the work support 18. The work support table 18 can be moved in the cutting and feeding direction (XX direction) by the cutting and feeding mechanism 22. Further, the work support table 18 is moved by the work indexing mechanism 24 in the work indexing direction (ZZ direction). ) Can be moved. The cutting and feeding mechanism 22 and the work indexing mechanism 24 are driven by a command signal from a control device 26. Further, the cutting and feeding mechanism 22 is provided with a position sensor 27, and controls the amount of movement of the ingot 20 in the X direction by the control device 26.
Can be entered. Further, a pair of air pads 28, 28 is provided on the upper surface of the blade 14 as shown in FIG.
Is arranged. Further, a pair of non-contact type blade sensors 30, 30 are arranged close to the air pads 28, 28. This air pad 28, 28, blade sensor 3
2, 0 and 30 are arranged on both sides of the cutting ingot 20 as shown in FIG.
8. The blade sensor 30 is disposed so as to be located near the inner peripheral blade 16 of the blade 14. Therefore, when air is jetted 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 are connected to an air pressure adjusting device 32 shown in FIG.
Is controlled by a command signal from the control device 26. The blade sensors 30, 30 measure the displacement of the blade 14, and a measurement signal from the blade sensors 30, 30 is input to a controller 26, which can control the air pressure regulator 32 based on the signal. It has become.

Further, as shown in FIG. 4 and FIG.
4 is provided with nozzles 34, 34,
Numeral 34 applies a downward or upward force to the blade 14 by blowing air between the ingot 20 and the blade 14 or between the wafer being cut and the blade 14.
Due to the amount of air blown, a force is applied to the blade 14 on an average basis (although the gap entrance is high) with respect to its unit area, so that more change can be obtained near the center of the blade 14. In other words, it is possible to control the blade 14 to have a shape having an appropriate curve in the YY direction.

The nozzles 34, 34 are connected to and controlled by an air pressure adjusting device 32. The cutting method according to the present invention is performed as follows using the slicing machine configured as described above. First, control in the XX direction will be proved. The blade 14 is stretched with a predetermined tension by a blade stretching mechanism of the chuck body 12. After the blade 14 is set, air of a predetermined pressure is blown from the air pads 28 before cutting. As a result, the blade 14 shown in FIG.
As shown in FIG. In this state, sufficient rigidity is given to the vicinity of the inner peripheral blade 16 of the blade 14, and cutting is started with the downwardly bent position as a reference (zero) position. The position of the blade 14 at this time is detected by the blade sensors 30 and 30 and stored in the control device 26.

In this state, the cutting and feeding mechanism 22 is operated to move the work support base 18 in the X direction, thereby cutting the ingot 20. The control amount of the air pad 28 during cutting of the ingot is given by the following equation. Pi + ₁ = (Pi−Qi) × f (X)... Pi: control amount of air pad 28 at point i Qi: measured value of blade sensor 30 at point i f (X): type of control device, blade dimensions , A function of cutting control determined by the size of the ingot and the position of the blade sensor.

Here, P and Q denote the reference displacement at the start of cutting as 0.
Is the displacement difference. According to the embodiment, the measured value of the blade sensor 30 indicating the displacement of the blade 14 and the measured value of the linear sensor 27 indicating the cutting position are input to the control device 26, and the control conversion is performed by the above equation, and the air pressure adjusting device A control signal is sent from the control device 26 to 32 to control the air pad 28. By performing this control, the cutting edge around the ingot can be adjusted to the height at the start of cutting.

Next, to prove the control in the Y-Y direction, when air is sent by the nozzle 34, a downward or upward force is applied to the blade. As shown in FIG. 7, as the cutting progresses, the air pressure effect increases, so that the amount of air blowout is controlled so as to decrease. As a result, as shown in FIG. And it gradually decreases after this. The coefficient of the amount of air blown is determined by the change of the blade and the value of the target warpage.

In the above embodiment, the blade is bent by air pressure. However, fluid pressure may be used, or other pressing means in the Z-axis direction may be used. The control in the Y-Y direction may be performed by changing the pressing position of the air pad to curve the blade.

[0022]

As described above, according to the method for cutting a slicing machine according to the present invention, the cutting direction (X-X
Direction) and a direction (YY direction) orthogonal to the cutting direction, a wafer having an arbitrary warped shape can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a plan view thereof.

FIG. 3 is a schematic sectional view taken along line AA in FIG. 2;

FIG. 4 is a drawing showing an arrangement of nozzles of the present invention.

FIG. 5 is a drawing showing the arrangement of nozzles of the present invention.

FIG. 6 is a drawing showing a relationship between a cutting end area and a cutting position.

FIG. 7 is a drawing showing a relationship between an air blowing amount and a cutting position.

FIG. 8 is a drawing showing the relationship between air pressure and cutting position.

FIG. 9 is an explanatory view showing a conventional slicing method.

FIG. 10 is an explanatory view showing a conventional slicing method.

FIG. 11 is an explanatory view showing a conventional slicing method.

[Description of Signs] 14 ... Blade 16 ... Inner peripheral blade 20 ... Ingot 26 ... Control device 28 ... Air pad 30 ... Blade sensor 34 ... Nozzle

Claims (2)

(57) [Claims] In a slicing machine for cutting a crystal ingot into thin flakes with an inner peripheral blade of a donut-shaped rotating blade , a side surface of the blade is attached to a side surface of the blade during cutting of the crystal ingot.
Controls the displacement of the cutting direction of the blade (X-X direction) by injecting fluid from a direction perpendicular to the blade, blade
By controlling the displacement direction (Y-Y direction) by injecting fluid perpendicular to the cutting direction of the blade to de, specified anti
The method of cutting slicing machine, characterized by disconnecting the wafer shape Ri. 2. A direction orthogonal to a cutting direction of the blade.
(Y-Y direction) displacement between ingot and blade
Or by spraying fluid between the wafer and blade during cutting
The slicing according to claim 1, wherein the slicing is controlled.
Machine cutting method.