JP2000042896A - Cutting method for wire saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the waviness of the cutting surface by detecting a wire abrasion quantity after cutting a workpiece, and independently controlling a new wire supply quantity, a wire traveling speed or a workpiece cutting feeding speed according to a measured wire abrasion quantity. SOLUTION: At ingot 32 cutting time, a wire diameter and a deviative diametrical difference of a wire 14 delivered from a wire row 20 after cutting an ingot 32 is measured in a wire diameter/deviative diametrical difference measuring device 28B arranged in a wire traveling passage on the winding side (wire reel 12B side). A new wire supply quantity, a wire traveling speed and a cutting feeding speed at ingot 32 cutting time are properly controlled to respective initial values or preset values so as to be efficiently cut without deteriorating the accuracy of the cutting surface by the wire diameter and the deviative diametrical difference of this measured wire 14. Thus, the wire diameter of the wire 14 can be always stabilized by always controlling this new wire supply quantity at ingot 32 cutting time.

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 wire saw, and more particularly, to a new wire supply amount when cutting a workpiece.
Calculate the running speed of the wire and the cutting feed speed of the workpiece,
It relates to a method for controlling cutting.

[0002]

2. Description of the Related Art In a wire saw, a workpiece is pressed against a traveling wire, and a working fluid containing abrasive grains is supplied to a contact portion between the wire and the workpiece, so that the workpiece is wrapped by the wire. It is a device for cutting. Therefore,
The wire used for cutting is also wrapped at the time of cutting, and becomes thin or uneven wear. For this reason, a new wire is always supplied to the wire, and at the same time, the wire running speed and the cutting feed speed of the workpiece are optimally set, and the cutting accuracy is reduced due to a change in the wire diameter and the deterioration of the wire diameter difference. Need to be prevented.

[0003] By the way, a wire running method of a wire saw is a method in which a wire is fed from one wire reel and wound on the other wire reel as it is (one-way feeding method), or a wire fed from one wire reel is reciprocated. There are two systems (a bidirectional feed system) in which the wire is wound on the other wire reel while being made to rotate. In the case of the bidirectional feed method, how to set the feed amount in the forward direction and the feed amount in the backward direction, that is, how to set the amount of the wire that is actually wound on the other wire reel (the new wire supply amount). ,
This has a great effect on the processing accuracy of the wafer to be cut.

Conventionally, a supply amount of a new wire in the bidirectional feed system is controlled by a diameter of a workpiece to be cut, a wire diameter of a wire to be used, or the like, in order to prevent undulation of a cut surface of the workpiece.
The operator assumed the amount of wear of the wire from the cutting feed speed of the workpiece, and set the amount based on the assumed value.

[0005]

However, the actual amount of wire wear is often far from the expected value, and uneven wire wear is not taken into account. For this reason, the set value of each cutting condition is not an optimum value, and causes a decrease in the cutting accuracy of the wafer. The present invention
In view of such circumstances, an object of the present invention is to provide a method for cutting a wire saw that can optimally set appropriate cutting conditions for the wire saw.

[0006]

According to the present invention, there is provided a reciprocating traveling wire saw which presses a workpiece against a traveling wire and cuts the workpiece into a large number of thin wafers. Detecting the amount of wire wear after, according to the measured amount of wire wear, the wire new wire supply amount, wire travel speed, or workpiece cutting feed speed alone, or wire new wire supply amount, wire travel speed, or The present invention is characterized in that two or more of the workpiece cutting feed speeds are controlled in combination. According to the present invention, the amount of wire abrasion after cutting the workpiece is detected, and according to the measured amount of wire abrasion, the wire new wire supply amount, the wire traveling speed, or the workpiece cutting feed speed alone or the wire Control is performed by combining two or more of the new wire supply amount, the wire traveling speed, and the workpiece cutting feed speed. As a result, the undulation of the cut surface can be reduced, the cutting time can be shortened, and the wire can be effectively used without waste, so that extremely economical cutting can be performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a wire running control method for a wire saw according to the present invention will be described below in detail with reference to the accompanying drawings. First, the overall configuration of a bidirectional feed wire saw will be described. As shown in FIG. 1, the wire 14 unreeled from one wire reel 12A
Are wound around three groove rollers 18, 18, 18 through a wire running path formed by guide rollers 16, 16,.... These three groove rollers 18, 1
A large number of grooves are formed at a constant pitch on the outer peripheral portions of the grooves 8 and 18, respectively. The wire 14 is sequentially wound around the grooves of the groove roller 18 to form a parallel wire row 20.
To form Then, the wire 1 on which the wire row 20 is formed
The wire 4 is wound around the wire reel 12B on the other side through the wire running path on the other side formed symmetrically with the three groove rollers 18, 18, 18 therebetween.

Here, the pair of wire reels 12A,
Motors 22A and 22B are respectively connected to the groove rollers 12B.
8, the wire 14 reciprocates at high speed between the pair of wire reels 12A and 12B. On the wire running paths formed on both sides of the wire row 20, wire guide devices 24A, 24B,
Dancer rollers 26A and 26B and wire diameter-diameter difference measuring devices 28A and 28B are provided. The wire guide devices 24A and 24B guide the wire 14 from the wire reels 12A and 12B at regular intervals, and form dancer rollers 26A and 24B.
26B applies a predetermined tension to the wire 14 on which a weight of a predetermined weight is suspended and travels. Also, wire wire diameter-
The eccentricity difference measuring devices 28A and 28B
Is measured. A work feed table 30 that moves vertically with respect to the wire row 20 is installed above the wire row 20. An ingot 32 as a workpiece is held at a lower portion of the work feed table 30.

In the wire saw 10 configured as described above, the cutting of the ingot 32 is performed by pressing the ingot 32 against the wire row 20 running at high speed.
At this time, a slurry is supplied to the wire array 20 from a slurry tank (not shown) via slurry injection nozzles 34, 34, and the ingot 32 is cut into wafers by a lapping action of abrasive grains contained in the slurry. You.

First, a method for determining a wire eccentricity difference and a cross-sectional area, which is a means for detecting a wire wear amount according to the present invention, will be described. Wire diameter-diameter difference measuring device 28A, 28
By measuring the major axis and minor axis of the wire at two or more positions using B, the amount of uneven wear of the wire can be known. As examples of the value indicating the amount of wear of the wire, the following formulas (1) and (2) show calculation examples of the eccentricity difference and the wire cross-sectional area.

[0011]

[Equation 1] Deflection difference = wire major diameter-wire minor diameter ... (1)

[0012]

## EQU2 ## Wire cross-sectional area = π × wire major axis × wire minor axis / 4 (2) Equation (2) approximates the cross-sectional area of the wire as an ellipse. Next, a method for controlling a supply amount of a new wire according to the present invention will be described. In the wire saw 10 of the present embodiment,
By setting the wire feed amount in the direction (forward direction) from the wire reel 12A to the wire reel 12B larger than the wire feed amount in the direction (return direction) from the wire reel 12B to the wire reel 12A, on average, the wire The wire 14 is supplied in a direction (forward direction) from the reel 12A to the wire reel 12B.

Here, as shown in FIG. 2, a direction from the wire reel 12A to the wire reel 12B (forward direction).
The wire feed amount L _F, when the wire feed amount in the direction toward the wire reel 12B on the wire reel 12A (backward) and L _B, the wire 14 by one reciprocation, L
Made by the difference _F -L _B from the wire reel 12A to proceed to wire reel 12B. A difference new line feed amount of L _F -L _B, L _F -L per round trip (1 cycle)
The unused wire 14 corresponding to the difference _B is the wire reel 1
Supplied from 2A.

The accuracy of the wafer to be cut depends on how the new line supply amount is set. That is, when cutting the lower end of the ingot 32 and when cutting the center of the ingot 32, the wire 1
4 is different in the distance of contact with the ingot 32, so that the amount of wear of the wire 14 is also different (when the central portion of the ingot 32 is cut, the wire 14 is more worn than when the lower end of the ingot 32 is cut). 14). Therefore, with the same new wire supply amount throughout, the wire diameter changes depending on the cutting position, and the cutting accuracy decreases.

A method for obtaining the new line supply amount set value will be described below. First, the new line supply coefficient k1 in equation (3)
Explain how to find. The wear limit value of the wire 14 is set in consideration of the required accuracy of the wafer, and the new wire supply coefficient k1 is set to be the wear limit value. For example, assuming that the standard of the variation in the thickness of the wafer within one ingot is 5.3 μm and the wire diameter of the wire used is 0.178 mm, the diameter wear limit value is 0.178−0.0053 =
Since it is 0.1727 mm, the new line supply coefficient k1 is set such that the 0.178 mm wire is worn and becomes 0.1727 mm. The new line supply coefficient k1 is
Set value of wire diameter and cutting feed speed of ingot 32,
The operator sets the initial value of the wire traveling speed, the set value of the new wire supply amount, or the like, or stores the value in a storage device of the wire saw controller 36 in advance.

Next, an example of an equation for calculating the new line supply amount set value WL during cutting is shown in equation (3), and the result of calculating the new line supply amount set value WL during cutting by the above equation (3) is shown. Figure 5 shows an example of
FIG. 3 illustrates the constants, and FIG. 4 illustrates the chord length of the cut surface. In order to obtain the new line supply amount setting value WL, the cutting path length of the wire is obtained from the length L of the cut face chord, the ingot length GL, and the wire winding pitch P, and the cutting force coefficient f1 based on the wire tension is obtained. And a new wire supply coefficient k1 calculated from the workpiece cutting feed speed, the physical properties of the workpiece, the wire traveling speed, the physical properties of the wire, the physical properties of the abrasive grains, and the like, and the reciprocating cycle C of the wire. WL: Set value of new line supply amount (m / min) L: Chord length of cut surface (m) GL: Ingot length (m) k1: New line supply amount coefficient WL ₀ : Initial value of new line supply amount ( m / min) P: wire winding pitch (m) f1: cutting force coefficient C: number of wire reciprocating cycles (times / min)

[0017]

(Equation 3) Here, the length L of the chord of the cut surface in the equation (3) is a variable that differs depending on the site where the ingot 32 is cut, as shown in FIG. The chord length L of the cut surface at the portion where the cross-sectional shape of the ingot 32 is circular can be approximated by the following method.

L: length of chord of cut surface (m) DG: diameter of ingot 32 (m) Z: distance from lower end of ingot 32 to cutting position (m)

[0019]

L = 2 × ((DG / 2) ² − (DG / 2−Z) ² ) ^1/2 (4) The above equations (3) and (4) are replaced by the wire saw controller 3
6 to determine a new line supply amount set value WL at an arbitrary cutting position Z. Also, instead of calculating the above equation (4) inside the wire saw, the operator can use Z1, Z1 shown in FIG.
The chord length L of the cut surface at the cutting position of Z2 and Z3 may be calculated, and the calculated value may be input to the wire saw controller 36. However, when the operator sets Z1, Z2, and Z2 shown in FIG.
When the chord length L of the cut surface at the cutting position of Z3 is calculated and the value is input to the wire saw control device 36, the number of input points is reduced to reduce the number of input operations by the operator, and the wire saw control device 36 is used. In, a new line supply amount set value WL at an arbitrary cutting position Z may be determined by interpolating between points input by the operator with a straight line or a curve.

FIG. 5 shows a calculation example of the new line supply amount set value WL obtained by the above method. In the calculation example of FIG.
When the value is 0, that is, when the wire 14 comes into contact with the ingot 32 and cutting starts, the supply amount of new wire increases in proportion to the chord length of the cut surface. New line supply amount set value W
L becomes the maximum value when the portion passing through the center of the ingot 32 is cut (when Z = DG / 2) and thereafter decreases, but the portion where the chord length of the cut surface becomes constant (Z = Z ₃ ) takes a fixed value.

The means for supplying a new line based on the determined new line supply amount set value WL controls and calculates the obtained new line supply amount set value WL, outputs the calculation result to each motor, and drives the groove roller 18. Together with the motors 22A, 22B
By rotating the wire reels 12A and 12B. Next, a method of setting the initial value of the wire running speed Vw will be described with reference to FIG.

Normally, the initial value of the wire running speed Vw is set to the upper limit of the capability of the wire saw with emphasis on the cutting efficiency.
In this embodiment shown in FIG. 6, the wire running speed has a constant value irrespective of the cutting amount Z. Although not implemented in this embodiment, the wire running speed Vw may be a variable based on the distance Z from the lower end of the workpiece to the cutting position, the cutting feed speed Fw, and the like.

The means for running the wire at the determined wire running speed Vw controls the calculated wire running speed Vw, outputs the calculation result to each motor, drives the groove roller 18 at the specified speed, and Drive the wire reels 12A, 12B
Is achieved by rotating Next, a method of setting the cutting feed speed set value FL will be described.

The cutting feed speed set value FL is calculated by the following equation (5).
FIG. 7 shows a setting example of the cutting feed speed setting value FL. In the calculation example of FIG. 7, when Z = 0, that is, even after the wire 14 is in contact with the ingot 32 and the cutting is started, the cutting is continued at the initial cutting feed speed for a while, and the cutting area per unit time reaches Sc. Thereafter, the cutting feed speed setting value FL decreases in substantially proportion to the chord length of the cutting surface because the cutting area per unit time is constant. The cutting feed speed setting value FL becomes the minimum value when cutting a portion passing through the center of the ingot 32 (when Z = DG / 2) and thereafter increases, but the length of the chord of the cut surface becomes constant. The portion (Z = Z _{3 and} subsequent) has a constant value.

FL: cutting feed speed set value (m / min) Si: cutting area per unit feed (mm ² / m) Sc: cutting area constant (m ² / min) FL ₀ : cutting feed speed initial value (m / Min)

[0026]

(Equation 5) The above equations (4) and (5) are converted to the control device 3 of the wire saw.
6, the cutting feed speed set value FL at an arbitrary cutting position Z is determined. Also, instead of calculating the above equation inside the wire saw, the operator can use Z1, Z2 shown in FIG.
The cutting feed speed setting value FL may be calculated from the cutting area Si per unit feed of the cutting surface at the cutting position of 2, 2 and the cutting area constant Sc, and the value may be input to the wire saw controller 36. However, when the operator sets the Z shown in FIG.
When calculating the cutting feed speed setting value FL at the cutting positions of 1, Z2, and Z3 and inputting the value to the wire saw control device 36, the number of input points is reduced to reduce the number of input operations by the operator, and the wire saw control device is reduced. At 36, the cutting feed speed set value FL at an arbitrary cutting position Z may be determined by interpolating between points input by the operator with a straight line or a curve.

The cutting area Si per unit time at the time of cutting the ingot may be obtained from a formula for calculating the area of a general circle, or a trapezoidal shape as shown below from the chord length of the cut surface shown in formula (4). May be approximated by the area of.

[0028]

(Equation 6) The ingot 32 is cut at the specified cutting feed speed by outputting the determined cutting feed speed set value FL to the work feed motor 50 after performing the control calculation. Although not implemented in the present embodiment, the cutting feed speed Fw may be a variable based on the wire feed speed or the like.

Next, an embodiment of the first invention will be described.
During cutting of the ingot 32, the winding side (the wire reel 1)
In the wire diameter-diameter difference measuring device 28B installed on the wire running path (2B side), the wire diameter and the diameter deviation of the wire 14 drawn out from the wire row 20 after cutting the ingot 32 are measured. The measured wire diameter of the wire 14,
Due to the deviation in diameter, the amount of new wire supplied during cutting of the ingot 32 and the wire traveling speed and the cutting feed speed are set to their initial values or set values so that cutting can be performed efficiently without deteriorating the accuracy of the cut surface. Control appropriately.

FIG. 8 shows an example of a method of calculating a new wire supply amount, a wire traveling speed, and a cutting feed speed during cutting by the control device 36. First, an outline of the calculation in the control device 36 will be described. When the cutting is started, it is calculated how much the wire diameter after ingot cutting measured by the wire diameter-diameter difference measuring device 28B and the measured value of the wire diameter difference have a margin with respect to the wear limit value. . If the calculation shows that there is enough wire diameter, reduce the new wire supply and
Use wires effectively and efficiently. When the diameter of the wire exceeds the wear limit, the supply amount of the new wire is increased so as not to deteriorate the accuracy of the cut surface of the wafer.

Next, if the difference in the diameter of the wire has a margin with respect to the wear limit, there is also a margin with respect to the required cutting accuracy, so that the difference in the diameter of the wire does not exceed the wear limit. Increasing the wire running speed and the cutting feed speed to shorten the cutting time and improve cutting efficiency. If the diameter difference exceeds the wear limit, the wire traveling speed and the cutting feed speed are immediately reduced so as not to deteriorate the accuracy of the cut surface of the wafer.

The operation of the control device 36 will be described in the order of steps shown in FIG. In the example of FIG. 8, in step 110, the respective values are substituted for a new line supply amount initial value Ww ₀ , a wire traveling speed initial value Vw ₀ , and a cutting feed speed initial value Fw ₀ . Next, in step 120, the wire diameter-diameter difference measuring device 28A, 28
The values of the wire diameter d and the diameter difference c measured at 8B are taken into the control device 36.

Next, in step 130, the diameter margin D and the deviation diameter margin C are calculated. Next, in step 140, the new wire supply amount Ww is increased or decreased in accordance with the new wire supply amount proportional constant kw and the diameter margin D obtained in step 130, so that the deterioration of the processing accuracy due to the decrease in the wire diameter is anticipated. In addition, when there is a margin in the wire diameter, unnecessary consumption of the wire is suppressed and importance is placed on economy.

For example, in the case of the above example, the diameter wear limit value D
Since l is 0.172.7 mm, when the measured wire diameter d is 0.177 mm, the diameter margin D is 0.1 mm.
0043, and the new line supply amount output value Ww _n is calculated in step 140, only 4.3 × 10 ^-6 × kw than new line feed amount set value WL _n (m / min) is reduced, the wire unnecessary for Emphasis on economical efficiency with low consumption. That is, in the backward direction (from the wire reel 12B to the wire reel 12B).
Increasing the percentage of direction towards A) wire feed amount L _B.

On the other hand, the measured wire diameter d is 0.171 m
If it is m, it is excessively worn, so the supply amount of the new wire is increased so that the measured wire diameter d does not become less than the diameter wear limit value Dl = 0.172.7 mm. That is, reducing the proportion of direction of the wire feed amount L _B toward the backward direction (wire reel 12A from the wire reel 12B). As described above, during the cutting of the ingot 32, the new wire supply amount W
By controlling w, the wire diameter of the wire 14 is stable throughout, and it is possible to cut a highly accurate wafer. In addition, as a result, the wire 14 can be supplied without excess and deficiency, so that extremely economical operation becomes possible.

Next, in step 150, the wire running speed Vw and the cutting feed speed Fw are increased according to the wire running speed proportional constant kv and the cutting feed amount proportional constant kf and the deviation difference margin C obtained in step 130, or This prevents the deterioration of the processing accuracy due to the deterioration of the wire diameter difference. If there is a margin in the wire diameter difference, the wire running speed and the cutting feed speed are increased, and unnecessary consumption of cutting time is suppressed to emphasize economic efficiency.

For example, as an example, it is assumed that the eccentric diameter difference wear limit value Cl of the wire is 0.005 mm, and when the measured eccentric diameter difference value c of the wire is 0.007 mm, the eccentric diameter difference c of the wire is 0.1 mm. wire running velocity output value Vw _n such that 005Mm, reduces the cutting feed speed output value Fw _n. On the other hand, when the measured value of the wire eccentricity difference c is 0.002 mm, there is a margin in the processing accuracy, so that the wire traveling speed output value Vw is set so that the measured value of the wire eccentricity difference c does not exceed 0.005 mm. _n , the cutting feed speed output value Fw _n is increased.

[0038] Thus, during the cutting of the ingot 32, at all times the wire traveling velocity output value Vw _n, by controlling the cutting feed speed output value Fw _n, polarized diameter difference of the wire 14 does not deteriorate, the accuracy High wafers can be cut and very economical operation is possible.
In step 160, the new line supply amount output value Ww _n was determined by calculation, and held wire traveling velocity output value Vw _n, the cutting feed speed output value Fw _n until the update of the next output value, the power after the control operation Output to the source motor.

In the next step 170, n → n−1, that is, the new line supply amount output value Ww _n , the wire traveling speed output value Vw _n , and the cutting feed speed output value Fw _n are converted into the previous output value Ww
Preparations are made to replace _n-1 with Vw _n-1 and Fw _n-1 for use in the next calculation. In this embodiment, the new line supply amount output value Ww _n and wire traveling speed output value Vw _n, cutting feed rate output value proportional action diameter margin D and polarized diameter difference margin C is the parameter to calculate the Fw _n However, the present invention is not limited to the proportional operation, but can also be achieved by a proportional integral operation or other control means. In the above example, but not to change the new line feed amount output value Ww _n in step 150, it is not limited thereto, may be changed new line feed amount output value Ww _n in step 150. Further, in the above example not changing the wire traveling velocity output value Vw _n and cutting feed speed output value Fw _n in step 140,
The invention is not limited thereto, may be changed wire traveling velocity output value Vw _n and cutting feed speed output value Fw _n also in step 140.

As the wire diameter-diameter difference measuring devices 28A and 28B for measuring the wire diameter of the wire 14, a contact type length measuring device or a non-contact type detecting device is used. For example, when a laser length measuring device is used, at least wire diameters in two directions of X and Y are measured, a wire diameter is obtained from an average of the wire diameters, and a deviation difference is calculated from a difference between the wire diameters in the two directions of X and Y. , To determine the cross-sectional area.

Next, a preferred example in the case of using a contact-type wire wear amount detecting device will be described. Since the wire 14 reciprocates, the traveling of the wire 14 is temporarily stopped when the traveling direction is switched. While the wire 14 is temporarily stopped, the wire 14 is sandwiched between the tracing stylus that moves up and down on the reference surface, and the distance of the tracing stylus from the reference surface is measured using a measuring means such as a differential transformer. At least wire diameters in the X and Y directions are measured, the wire diameter is determined from the average, and the deviation difference is determined from the difference between the wire diameters in the X and Y directions. According to this method, since the wire diameter of the wire 14 can be directly measured, an accurate wire diameter deviation difference can be grasped.

In this embodiment, the wire wear amount detecting device 28
Although A and 28B are provided at two places on both sides of the groove roller 18, the present invention is not limited to this, and one place on one side of the groove roller 18 or a wire running path after a wire cleaning unit (not shown) may be used. The effect of can be obtained. As described above, according to the wire saw cutting method according to the present invention, the wire diameter and the wire diameter difference are measured using the wire diameter-diameter difference measuring devices 28A and 28B shown in FIG. Detects the amount of wire abrasion after cutting the workpiece and, based on the measured amount of wire abrasion, sets the new wire supply, wire running speed, or workpiece cutting feed rate alone, or the new wire supply, wire By controlling two or more of the running speed or the workpiece cutting feed speed, the undulation and roughness of the cut surface can be reduced, the cutting time can be reduced, and the wire can be used effectively and efficiently. This allows very economical cutting.

Next, an embodiment of the second invention will be described.
FIG. 9 is a diagram showing the relationship between the rate of decrease in the wire diameter due to the wear of the wire and the undulation of the cut surface of the wafer. As shown in FIG. 9, when the wire is worn and the wire diameter is reduced by 3% or more, the cut surface undulation of the wafer rapidly deteriorates and exceeds the wafer surface undulation allowable value. Also,
FIG. 10 is a diagram showing the relationship between the ratio of the wire cross-sectional area due to uneven wear of the wire and the undulation of the cut surface of the wafer. As shown in FIG. 10, when the wire is worn and the cross-sectional area of the wire is reduced by 6% or more, the undulation of the cut surface of the wafer rapidly deteriorates and exceeds the allowable value of the undulation of the wafer surface. Here, when the wire traveling speed is reduced, the cutting load is reduced, and wear and uneven wear of the wire can be suppressed.
However, if the wire traveling speed is too slow in order to suppress the wear and uneven wear of the wire, the cutting efficiency will be significantly deteriorated. As described above, according to the wire saw cutting method according to the present invention, the wire diameter and the wire cross-sectional area are measured using the wire diameter-diameter difference measuring devices 28A and 28B shown in FIG. When the wire diameter after cutting the wafer is 3% or 6% or more in the wire cross-sectional area with respect to the previous wire diameter, the wire traveling speed does not exceed 25% as compared with the initial set value. It controlled so that it might become slow in the range. FIG. 6 shows an embodiment. According to the present invention, the wire traveling speed is set within a wire traveling speed control range which is a portion between the wire speed set value shown in FIG. 6 and the wire speed variable lower limit value. According to the present invention, when the wire diameter after cutting the wafer is 3%, or when the wire cross-sectional area is worn by 6% or more, the wire traveling speed is reduced within a range not exceeding 25% as compared with the initial set value. The wear of the wire is suppressed to about 3% in the wire diameter of the wire and about 6% in the wire sectional area, and the cut surface undulation does not exceed the wafer surface undulation allowable value. In addition, it is economical because wires can be used effectively.

Next, an embodiment of the third invention will be described.
As shown in FIGS. 9 and 10, when the wire is worn and the wire diameter is reduced by 3% or more, or when the wire is worn and the wire cross-sectional area is reduced by 6% or more, the cut surface undulation of the wafer is sharply increased. It deteriorates and exceeds the wafer undulation tolerance. Here, if the cutting feed speed of the ingot to be processed is reduced, the cutting load is reduced, and the wear and uneven wear of the wire can be suppressed. However, if the cutting feed speed is too slow in order to suppress the wear and uneven wear of the wire, the cutting efficiency will be significantly deteriorated. As described above, according to the method for cutting a wire saw according to the present invention, FIG.
The wire diameter and the cross-sectional area of the wire were measured using the wire diameter-diameter difference measuring devices 28A and 28B shown in FIG. Or when the wire cross-sectional area wears by 6% or more, the cutting feed speed is compared with the initial set value by 50%.
%. FIG. 7 shows an embodiment. According to the present invention, the cutting feed speed is set within a cutting feed speed control range which is a portion between the cutting feed speed setting value shown in FIG. 7 and the cutting feed speed variable lower limit value. According to the present invention, the wire diameter after cutting the wafer is 3
% Or when the wire cross-sectional area wears by 6% or more,
Since the cutting feed speed is reduced within a range not exceeding 50% as compared with the initial set value, the wear of the wire is reduced by 3 mm in the wire diameter.
%, And the wire cross-sectional area is suppressed to around 6%, and the cut surface undulation does not exceed the wafer surface undulation tolerance. Also, the cutting time is not unnecessarily long and is economical.

Next, an embodiment of the fourth invention will be described.
As shown in FIGS. 9 and 10, when the wire is worn and the wire diameter is reduced by 3% or more, or when the wire is worn and the wire cross-sectional area is reduced by 6% or more, the cut surface undulation of the wafer is sharply increased. It becomes worse and exceeds the allowable value of the undulation of the wafer. Here, when the new wire supply amount is increased, a large amount of new wire is supplied, so that excessive wear and uneven wear of the wire can be suppressed. However, if the supply amount of the new wire is excessively increased in order to suppress the abrasion and uneven wear of the wire, the cost of the extra wire increases and the cutting cost is remarkably deteriorated. As described above, according to the wire saw cutting method according to the present invention, the wire diameter and the wire cross-sectional area are measured using the wire diameter-diameter difference measuring devices 28A and 28B shown in FIG. For the wire diameter before cutting,
When the wire diameter after cutting the wafer was worn by 3% or 6% or more in the wire cross-sectional area, the supply amount of the new wire was controlled so as to increase within a range not exceeding 30% as compared with the set value. FIG. 5 shows an embodiment. According to the present invention, the new line supply amount is set within a new line supply amount control range which is a portion between the new line supply amount set value shown in FIG. 5 and the new line supply amount variable upper limit value. According to the present invention, when the wire diameter after cutting the wafer is worn by 3% or 6% or more in the wire cross-sectional area, the new wire supply amount is increased within a range not exceeding 30% as compared with the set value. , Wire wear is 3 in wire diameter
%, And the wire cross-sectional area is suppressed to around 6%, and the cut surface undulation does not exceed the wafer surface undulation tolerance. Also, the cutting time is not unnecessarily long and is economical.

Next, an embodiment of the fifth invention will be described.
As shown in FIGS. 9 and 10, when the required wafer surface undulation of the cut surface is large, it is necessary to set a large amount of wire wear or uneven wear while maintaining the allowable value of the wafer surface undulation. It is possible. When the wire is worn and the wire diameter is reduced by 3 to 8% or more due to the required surface undulation of the wafer, or when the wire is worn and the wire cross-sectional area is reduced by 6 to 15% or more, a new wire is required. Excessive wire by controlling the wire feed rate, wire running speed, or workpiece cutting feed rate alone, or by combining two or more of the wire new wire feeding rate, wire running speed, or workpiece cutting feed rate Wear and uneven wear can be suppressed, and cutting efficiency can be improved. As described above, according to the wire saw cutting method according to the present invention, the wire diameter and the wire cross-sectional area are measured using the wire diameter-diameter difference measuring devices 28A and 28B shown in FIG. The wire diameter after cutting the wafer is 3 to 8% of the wire diameter before cutting, or the wire cross section is 6 to 8%.
When worn by 15% or more, the wire feed rate, wire travel speed, or workpiece cutting feed rate alone, or two or more of the wire feed rate, wire travel speed, or workpiece cut feed rate Was controlled in combination. Thereby, the wear of the wire is 3 to 8 in the wire diameter of the wire.
%, And the wire cross-sectional area is suppressed to around 6 to 15%, and the cut surface undulation does not exceed the wafer surface undulation tolerance. Further, the cutting time can be shortened, which is economical.

Next, an embodiment of the sixth invention will be described.
As shown in FIG. 10, when the wire is worn and the wire cross-sectional area is reduced by 6% or more, the undulation of the cut surface of the wafer rapidly deteriorates and exceeds the undulation allowable value of the wafer.
Here, instead of the wire cross-sectional area, the wire diameter is measured in two directions, a major axis and a minor axis, and the diameter difference between the major axis and the minor axis is used as the eccentric diameter difference of the wire. If the feed rate, wire travel speed, or workpiece cutting feed rate is controlled alone or in combination with two or more of the new wire feed rate, wire travel speed, or workpiece cutting feed rate, excessive wear and unevenness of the wire will occur. Wear can be suppressed and cutting efficiency can be improved. As described above, according to the method for cutting a wire saw according to the present invention, the wire diameter-diameter difference measuring devices 28A and 28B shown in FIG. The difference between the major axis and the minor axis is defined as the eccentricity of the wire, and a new wire is supplied according to the determined eccentricity difference so that the eccentricity of the wire is 1.5% or less of the wire diameter before cutting. The amount, wire running speed, or workpiece cutting feed speed is controlled alone or in combination of two or more of the new wire supply amount, wire running speed, and workpiece cutting feed speed. Thereby, excessive wear and uneven wear of the wire can be suppressed, and cutting efficiency can be improved.

[0048]

As described above, according to the wire saw cutting method of the present invention, the amount of wire abrasion after cutting the workpiece is detected, and the supply amount of the new wire wire is determined according to the measured amount of wire abrasion. By controlling the wire traveling speed, or the workpiece cutting feed speed alone, or by combining two or more of the wire new wire supply amount, the wire traveling speed, or the workpiece cutting feed speed, the undulation of the cut surface can be reduced. The number of wires can be reduced, the cutting time can be shortened, and the wires can be used effectively and efficiently, so that extremely economical cutting can be performed.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a wire saw to which a wire traveling control method according to the present invention is applied.

FIG. 2 is an explanatory diagram illustrating traveling of a wire.

FIG. 3 is an explanatory diagram of each constant.

FIG. 4 is a diagram showing a chord length of a cut surface.

FIG. 5 is a diagram showing a cutting amount, a new line supply amount setting value, and a new line supply amount control range.

FIG. 6 is a diagram showing a cutting amount, a wire traveling speed initial value, and a wire traveling speed control range.

FIG. 7 is a diagram showing a cutting amount, a cutting feed speed initial value, and a cutting feed speed control range.

FIG. 8 shows an example of a calculation method in the control device 36.

FIG. 9 is a diagram showing the relationship between the wire diameter wear amount and the cut surface undulation.

FIG. 10 is a diagram showing the relationship between the wire uneven wear amount and the cut surface undulation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Wire saw 14 ... Wire 18 ... Groove roller 20 ... Wire row 28A, 28B ... Wire diameter-diameter difference measuring device 32 ... Ingot 36 ... Control device

 ──────────────────────────────────────────────────の Continued on the front page F term (reference) 3C058 AA05 BA04 BC02 CB03 DA03 DA17 3C069 AA01 BA06 BB01 BC03 BC06 CA04 CA05 DA03 EA01

Claims (6)

[Claims] 1. A workpiece is pressed against a traveling wire,
In a reciprocating traveling wire saw that cuts into a large number of thin wafers, the amount of wire abrasion after cutting the workpiece is detected, and according to the measured amount of wire abrasion, a new wire supply amount, a wire traveling speed, or a workpiece A method for cutting a wire saw, characterized in that the object cutting feed speed is controlled alone or in combination of two or more of a new wire supply amount, a wire traveling speed, and a workpiece cutting feed speed. 2. The wire saw cutting method according to claim 1, wherein a wear amount of the wire is 3% of a wire diameter after cutting the workpiece with respect to a wire diameter before cutting the workpiece. ,
Alternatively, when the wire cross-sectional area is worn by 6% or more, the wire running speed is slowed down within a range not exceeding 25% with respect to an initial set value to reduce the amount of wire abrasion. . 3. The wire saw cutting method according to claim 1, wherein an amount of wear of the wire is 3% of a wire diameter after cutting the workpiece with respect to a wire diameter before cutting the workpiece. ,
Alternatively, when the wire cross-sectional area is worn by 6% or more, the wire cutting amount is reduced by reducing the workpiece cutting feed speed within a range not exceeding 50% of an initial set value. Cutting method. 4. The wire saw cutting method according to claim 1, wherein an amount of wear of the wire is 3% of a wire diameter after cutting the workpiece with respect to a wire diameter before cutting the workpiece. ,
Alternatively, when the wire cross-sectional area is worn by 6% or more, the wire new wire supply amount is increased within a range not exceeding 30% with respect to an initial set value to reduce the wire wear amount. Cutting method. 5. The wire saw cutting method according to claim 1, wherein a wire wear limit value is set in advance with respect to a wire diameter before cutting the workpiece according to a required cutting accuracy. 3 to 8%, or 6-1 in wire cross section
When the wire wear amount exceeds the set value, the wire new wire supply amount, wire travel speed, or workpiece cutting feed speed is set alone, or the wire new wire supply amount, wire travel is set. A method for cutting a wire saw, characterized by controlling two or more of a speed and a workpiece cutting feed speed. 6. The new wire saw according to claim 1, wherein the wire diameter after cutting the workpiece does not exceed 1.5% due to the difference between the major axis and the minor axis. A wire saw characterized by controlling a supply amount, a wire traveling speed, or a workpiece cutting feed speed alone, or a combination of two or more of a new wire supply amount, a wire traveling speed, and a workpiece cutting feed speed. Cutting method.