JP2655756B2 - 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 adjacent to 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. 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 on the opposite side of the blade displacement 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, it is necessary to reduce the warpage in the manufacture of the wafer as a performance of the wafer. However, if the warp occurs during the wafer processing step after the slicing and cutting, the warp is specified in advance in the slicing and cutting. In some cases, a high-quality wafer with little warpage and high flatness is manufactured when the wafer is completed.

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

[0009]

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. Ingot position correcting means for moving the blade in the direction, blade pressing means for moving the blade in the axial direction of the blade, and blade displacement detecting means for detecting the axial displacement of the blade, And the displacement in the direction (Y-Y direction) perpendicular to the cutting direction of the blade is controlled by the pressing means of the blade to cut a wafer having a desired warped shape. It is characterized by the following.

[0010]

According to the present invention, the displacement of the blade in the XX direction is controlled by the ingot position correcting means, and the displacement of the blade in the YY direction is controlled by the pressing means of the blade for cutting. 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.

[0011]

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 base 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. Furthermore,
An ingot position correcting mechanism 25 for moving the ingot 20 a minute distance in the axial direction of the blade 14 is provided. The ingot position correcting mechanism 25 is composed of a piezo element or the like. The cutting feed mechanism 22, the work indexing mechanism 24 and the ingot position correcting mechanism 25 are driven by a command signal from a control device 26. Further, a pair of air pads 28A and 28B are arranged on the upper surface of the blade 14, as shown in FIG. Further, a pair of non-contact type blade sensors 30A and 30B are arranged close to the air pads 28A and 28B. This air pad 2
As shown in FIG. 2, the air pads 28A, 28B and the blade sensors 30A, 30B are arranged on both sides of the cutting ingot 20, and the air pads 28A, 28B and the blade sensors 30A, 30B are arranged on the inner peripheral blade 16 of the blade 14.
It is arranged to be located near. Therefore, when air is ejected from the air pads 28A and 28B, as shown in FIG. 3, the blade 14 bends downward at the lower portion of the air pads 28A and 28B, and the central portion sandwiched between the air pads 28A and 28B is upwardly convex. It will bend in a shape.

The air pads 28A and 28B are connected to an air pressure adjusting device 32 shown in FIG. 1, and the air pressure adjusting device 32 is controlled by a command signal from a 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.

The cutting method according to the present invention using the slicing machine configured as described above is carried out as follows. The blade 14 is stretched with a predetermined tension by a blade stretching mechanism of the chuck body 12. After the blade 14 is stretched, air having a predetermined pressure is blown from the air pads 28A and 28B before cutting. The air pads 28A and 28B are arranged near the inner periphery of the inner peripheral blade 16 and locally apply air pressure from one side,
The portion of the inner peripheral blade cut into the ingot 20 is curved. The degree of curvature of the air pads 28A, 28B
Can be adjusted by the position and air pressure. From this state, the work indexing mechanism 24 moves downward so that the wafer has a predetermined thickness. The ingot 20 is cut and fed toward the inner peripheral blade as shown in FIG. The cutting is started with the cutting start position as a reference (zero) position. The position of the blade 14 at this time is detected by the blade sensors 30A and 30B, and the control device 26 stores it. During this cutting, the work position correcting mechanism 25 is used.
Performs the correction movement of the ingot so that the cutting start portion and the cutting end portion are curved in accordance with the ingot axial correction movement amount with respect to the cutting feed position of the ingot stored in the control device 26 in advance. That is, the workpiece position correcting mechanism 25 controls the axial displacement of the workpiece in the blade cutting direction (XX direction). On the other hand, during this cutting, the positions of the part (IN side) and the part (OUT part) where the inner peripheral blade 16 enters the ingot from the rotational direction into the ingot are detected by the blade sensors 30A and 30B, and the IN side and the OUT side are detected. Air pad 28 so that the position of
A, 28B controls the air pressure. That is, control is performed such that there is no displacement of the blade in a direction (Y-Y direction) orthogonal to the cutting direction of the blade. As a result, the wafer to be cut can be cut into a bowl-shaped wafer having a flat outer periphery as shown in FIG.

The above is the basic principle. The warpage of the wafer in the cutting feed direction (XX direction) is determined by the correction amount of the ingot position correcting mechanism 25, and the warpage in the cutting feed perpendicular direction (YY direction) is determined. Inner peripheral blade 16 is air pad 28A, 28B
Can be determined by the degree of bending. When the ingot 20 is cut by using the ingot position correcting mechanism 25 or the air pads 28A and 28B alone, a cylindrically shaped wafer as shown in FIG. 4 is processed. When correction is performed by both the ingot position correction mechanism 25 and the air pads 28A and 28B, a bowl-shaped wafer as shown in FIG. 5 is processed, and the magnitude and direction of the warpage can be determined by the curvature of the inner peripheral blade.

<Example 1> (1) The blade sensors 30A and 30B of the inner peripheral blade 16 are:
It is fixed near the maximum diameter of the ingot 20 at a position that does not come into contact with the ingot 20 during cutting and feeding. (2) During the cutting of the ingot 20, the air pads 28A and 28B adjust the air pressure and blow the air so that the displacement of the inner peripheral blade measured from the blade sensors 30A and 30B is maintained at the reference position where the cutting was started. . (3) During the cutting of the ingot 20, the workpiece position correcting mechanism 25 adjusts the inner peripheral blade 16 in accordance with the cutting feed of the ingot 20 by the degree of the curvature of the inner peripheral blade when the displacement of the inner peripheral blade starts cutting. The ingot 20 is moved in the axial direction. That is, the position of the ingot 20 is corrected along a certain reference curve.

<Example 2> (1) The blade sensors 30A and 30B of the inner peripheral blade 16 are:
It is assumed that it moves horizontally on the inner circumference so as to be in the vicinity of the ingot 20 at a position where it does not come into contact with the ingot 20 during cutting and feeding. (2) While cutting the ingot 20, the air pad 28A blows out air at a constant pressure and the air pad 28B blows out air by changing the air pressure so that the value of the blade sensor 30B becomes equal to the value of the blade sensor 30A. . This is due to the fact that the OUT side of the blade 14 is more likely to fluctuate after cutting than the IN side of the blade 14, and it is easier to control one air pad than to control both air pads. . (3) Work position correction mechanism 2 while cutting ingot 20
5 moves the ingot 20 in the axial direction of the inner peripheral blade 16 by the displacement of the blade sensor 30A.

[0018]

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 a cylindrical wafer.

FIG. 5 is a drawing showing a bowl-shaped wafer;

[Explanation of symbols]

 14 ... Blade 16 ... Inner peripheral blade 20 ... Ingot 25 ... Ingot position correction mechanism 26 ... Control device 28A, 28B ... Air pad 30A, 30B ... Blade sensor

Claims (1)

(57) [Claims] 1. A slicing machine for cutting a crystal ingot into flakes with an inner peripheral blade of a donut-shaped rotary blade, wherein the ingot position correcting means for moving the ingot in the axial direction of the blade and the blade in the axial direction of the blade. And a blade displacement detecting means for detecting an axial displacement of the blade. The displacement of the blade in the cutting direction (XX direction) is controlled by an ingot position correcting means. A cutting method for a slicing machine, comprising cutting a wafer having a desired warp shape by controlling displacement in a direction (Y-Y direction) orthogonal to a cutting direction of the blade by pressing means of the blade.