JP2013099795A - Semiconductor ingot cutting method, fixed abrasive grain wire saw, and wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor ingot cutting method and a fixed abrasive grain wire saw which are suitable for improving efficiency in cutting a semiconductor ingot while using a fixed abrasive grain wire saw.SOLUTION: A wire row 20 is configured by winding and hanging a fixed abrasive grain wire 10 around main rollers 18A, 18B several times. The wire row is made to travel in its longitudinal direction and a semiconductor ingot 50 is pressed against the traveling wire row 20 to be processed into a plurality of wafers by simultaneously cutting the semiconductor ingot 50 at several locations. The wire row is configured to set a wire traveling speed Vw when cutting the semiconductor ingot to a speed within a range of 100[m/min]<Vw<400[m/min].

Description

  The present invention relates to a method for cutting a semiconductor ingot using a fixed abrasive wire saw composed of a fixed abrasive wire having a plurality of abrasive grains fixed on the surface thereof.

  Conventionally, a fixed abrasive wire wound around a plurality of grooved rollers and having abrasive grains fixed on its surface is reciprocated in the axial direction, and the workpiece is pressed against the fixed abrasive wire that reciprocates and cut and fed. A work cutting technique using a wire saw that cuts a wafer into a wafer is disclosed (see Patent Document 1). In the invention according to Patent Document 1, when a workpiece such as a silicon ingot or a compound semiconductor ingot is cut into a wafer using a wire saw, the traveling speed of the fixed abrasive wire is set to 400 to 800 [m / min]. (See paragraph 0041).

  Further, for example, in Patent Document 2, a wire saw row is formed with a wire saw having superabrasive grains fixed on the outer peripheral surface of a high-strength wire, and the wire saw is 1000 [m / min] or more and 2500 [m / min]. A method of cutting a hard and brittle material such as a silicon ingot into a wafer by running at the following linear velocity is described.

JP 2011-20197 A JP 2001-54850 A

However, in a cutting process of a workpiece to a wafer by a wire saw, unintentional cutting in the middle of the processing occurs to the wafer due to waviness of the traveling wire or the like. This is a phenomenon of wafer dropout. For example, when a polycrystalline semiconductor ingot is cut, the dropout number tends to increase by increasing the wire traveling speed.
The present inventors pay attention to the increase in the number of wafer dropouts due to the increase in the wire traveling speed, and on the contrary, the wire traveling speed Vw is set to a speed slower than the conventional speed (400 [m / min] or more). An experiment for cutting a semiconductor ingot was conducted. From this experiment, it was discovered that the number of dropped wafers tends to decrease compared to the conventional speed by making the wire traveling speed slower than the conventional speed.

  Therefore, the present invention has been made from such a viewpoint, and a semiconductor ingot cutting method suitable for improving the cutting efficiency of a semiconductor ingot using a fixed abrasive wire saw, particularly a polycrystalline semiconductor ingot, and fixing An object of the present invention is to provide an abrasive wire saw and a cutting method or a wafer manufactured using the wire saw.

[Aspect 1] In order to achieve the above object, the semiconductor ingot cutting method according to aspect 1 is characterized in that the fixed abrasive wire having a plurality of abrasive grains fixed on the surface thereof is caused to travel in the longitudinal direction and travel. In the cutting method of cutting a semiconductor ingot with a fixed abrasive wire, the wire traveling speed Vw of the fixed abrasive wire saw when cutting the semiconductor ingot is in a range of 100 [m / min] <Vw <400 [m / min]. The speed was within.
This makes it possible to reduce the number of dropped wafers as compared with the conventional case where the semiconductor ingot is cut at a wire traveling speed of 400 [m / min] or more.

[Aspect 2] Furthermore, in the method for cutting a semiconductor ingot according to Aspect 2, the tension of the fixed abrasive wire at the cutting position is set to 2390 [N with respect to the diameter of the wire to be used. / Mm ² ] or more.
This makes it possible to reduce the amount of wire shake when cutting the semiconductor ingot.

[Aspect 3] Further, in the semiconductor ingot cutting method according to aspect 3, in the configuration of aspect 1 or 2, the fixed abrasive wire saw includes a plurality of fixed abrasive wire arranged opposite to each other in an axial parallel manner. Having a plurality of wire rows wound around a roller at a constant pitch;
The plurality of wire rows are traveled in the longitudinal direction, and the semiconductor ingot can be cut simultaneously by the traveled wire rows.
As a result, the semiconductor ingot can be simultaneously processed into a plurality of wafers.

[Aspect 4] On the other hand, in order to achieve the above object, the fixed abrasive wire saw according to aspect 4 is caused to travel by causing a fixed abrasive wire having a plurality of abrasive grains fixed on its surface to travel in the longitudinal direction. A fixed abrasive wire saw for cutting a semiconductor ingot with the fixed abrasive wire,
The wire travel speed Vw when cutting the semiconductor ingot is controlled to a speed within a range of 100 [m / min] <Vw <400 [m / min].

With such a configuration, it is possible to cut the semiconductor ingot by running the wire traveling speed of the fixed abrasive wire at a speed within a range of 100 [m / min] <Vw <400 [m / min]. It becomes.
As a result, it is possible to reduce the number of dropped wafers as compared with the conventional case where the semiconductor ingot is cut at a wire traveling speed of 400 [m / min] or more.

[Aspect 5] In order to achieve the above object, the wafer according to aspect 5 is manufactured using the cutting method according to any one of aspects 1 to 3.
Since it is a wafer manufactured using the above cutting method that can reduce the number of dropouts compared to the conventional method, at least the locations that cause dropouts with respect to the conventional traveling speed are compared with the wafers manufactured using the conventional method. Thus, a wafer with high precision such as a processing dimension is obtained.

[Aspect 6] In order to achieve the above object, the wafer according to aspect 6 is manufactured using the wire saw described in aspect 4.
Since it is a wafer manufactured using a wire saw that can reduce the number of dropouts compared to the conventional method, at least the locations that cause dropouts with respect to the conventional running speed are compared with the wafers manufactured using a conventional wire saw. Thus, a wafer with high precision such as processing dimensions is obtained.

  According to the semiconductor ingot cutting method and the fixed abrasive wire saw according to the present invention, there is an effect that the number of wafer drop-offs can be reduced as compared with the case where the polycrystalline semiconductor ingot is cut at a conventional wire traveling speed. can get.

(A) And (b) shows an example of the main structures of a fixed abrasive wire saw typically. (A) is sectional drawing at the time of cut | disconnecting the fixed abrasive wire 10 along a longitudinal direction, (b) is sectional drawing at the time of cut | disconnecting along the direction orthogonal to a longitudinal direction. FIG. 3 is a diagram schematically showing a state of cutting a semiconductor ingot 50 by a wire row 20. It is the figure which modeled the mechanism of the wire tension increase at the time of a cutting | disconnection. It is a figure which shows the relationship between the wire travel speed based on the cutting test which concerns on an Example, and the number of wafer drop-off number.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 5 are views showing an embodiment of a semiconductor ingot cutting method and a fixed abrasive wire saw according to the present invention.
(Constitution)
Hereinafter, the main structure of the fixed abrasive wire saw according to the present invention will be described with reference to FIGS. FIGS. 1A and 1B schematically show an example of the main configuration of a fixed abrasive wire saw. FIG. 2A is a cross-sectional view when the fixed abrasive wire 10 is cut along the longitudinal direction, and FIG. 2B is a cross-sectional view when it is cut along a direction orthogonal to the longitudinal direction. FIG. 3 is a diagram schematically showing a state of cutting the semiconductor ingot 50 by the wire row 20. FIG. 4 is a diagram schematically showing the mechanism of increasing wire tension at the time of cutting.

As shown in FIGS. 1A and 1B, the fixed abrasive wire saw 1 includes a fixed abrasive wire 10, wire bobbins 12A and 12B, main rollers 18A and 18B, tension rollers 16A and 16B, and guide rollers. 14A to 14D and motors 24A and 24B.
The fixed abrasive wire 10 is a wire having abrasive grains fixed on its surface, and is composed of a single wire having a length L (for example, ~ [km]).

  In the present embodiment, as shown in FIGS. 2A and 2B, the fixed abrasive wire 10 includes a wire strand 100 made of a material such as a high-tensile wire, diamond, CBN, SiC, GC, alumina, and the like. It is comprised from the abrasive grain 102 by a material, and the adhering material 104 (binder) which adheres the wire strand 100 and the abrasive grain 102. FIG. In addition, as for the fixing method of the abrasive grains, electrodeposition, resin fixing such as fixing (thermosetting, etc.) with an organic material or an inorganic material is used, but the present invention is not limited to these. The material of the strand may be a piano wire or a high tensile non-metallic fiber wire (including a fiber).

  Returning to FIG. 1, the main rollers 18 </ b> A and 18 </ b> B are arranged in parallel in the axial direction with a predetermined interval (for example, 650 [mm]) in the horizontal direction, and are supported rotatably. Further, each of the main rollers 18A and 18B has a plurality of grooves (not shown) along the roller rotation direction that are formed on the roller surface side by side in the axial direction at a constant pitch (eg, 325 [μm]). ing.

  The fixed abrasive wire 10 is wound along the grooves at positions opposed to the main rollers 18A and 18B in the plurality of grooves formed on the roller surface, and one end side in the axial direction of the main rollers 18A and 18B. It is wound while shifting the groove sequentially from the other end side. Thereby, the longitudinal direction of the wire part hung around the groove | channel in each opposing position is orthogonal to the axial direction (longitudinal direction) of main roller 18A, 18B. In addition, a plurality of wire portions orthogonal to the axial direction constitute a wire row 20 arranged at a constant pitch in the axial direction of the main rollers 18A and 18B.

  One end side of the fixed abrasive wire 10 extending from the winding start side is wound around the wire bobbin 12A via guide rollers 14A and 14C and a tension roller 16A. On the other hand, the other end extending from the winding end side of the fixed abrasive wire 10 is wound around the wire bobbin 12B via the guide rollers 14B and 14D and the tension roller 16B.

  The wire bobbin 12A is rotatably provided by a rotational driving force applied from the motor 24A. With this configuration, the wire bobbin 12A rotates in response to the application of either the forward rotation or the reverse rotation of the motor 24A, and the fixed abrasive wire 10 wound around the wire bobbin 12A becomes the main rollers 18A, 18b. It is drawn out to. Further, the wire bobbin 12A rotates in accordance with the application of the other rotational driving force of the forward rotation or the reverse rotation of the motor 24A, and the fixed abrasive wire 10 is wound around the wire bobbin 12A.

  The wire bobbin 12B is rotatably provided by a rotational driving force applied from the motor 24B. With this configuration, the wire bobbin 12B rotates according to the application of the rotational driving force of either forward rotation or reverse rotation of the motor 24B, and the fixed abrasive wire 10 wound around the wire bobbin 12B becomes the main rollers 18A, 18b. It is drawn out to. Furthermore, the wire bobbin 12B rotates in response to the application of either the forward rotation or the reverse rotation of the motor 24B, and the fixed abrasive wire 10 is wound around the wire bobbin 12B.

  The main roller 18A is a driving roller, and rotates by a rotational driving force applied from a driving motor (not shown). On the other hand, the main roller 18B is a driving roller or a driven roller, and is rotated by a rotational driving force applied from a driving motor (not shown), or is applied via the main roller 18A and the fixed abrasive wire 10. It rotates in the same rotational direction as the main roller 18A by the rotational driving force. Hereinafter, the main roller 18A is referred to as a driving roller 18A, and the main roller 18B is referred to as a driven roller 18B.

The tension roller 16A applies tension to the fixed abrasive wire 10 by the pressing force applied from the actuator 26A. Further, the tension roller 16B applies tension to the fixed abrasive wire 10 by the pressing force applied from the actuator 26B.
As shown in FIGS. 1 (a) and (b), the fixed abrasive wire saw 1 is further provided with two coolant nozzles 22, a ball screw 30, a motor 33, which are disposed above the wire row 20. A work feed table 34 and a slice base 36 are provided.

The coolant nozzle 22 injects coolant supplied at a predetermined water pressure by an electric pump (not shown) to a contact portion between the wire row 20 and the semiconductor ingot 50 when the semiconductor ingot 50 as a workpiece is cut. Nozzle.
Here, the coolant is, for example, cooling for cooling the heat generated in the contact portion, imparting lubricity for reducing cutting resistance, cleaning of the wafer after processing, rust prevention for metal parts, water It is a water-based liquid configured to have properties such as a reaction suppressing property between the workpiece and the workpiece.

  The ball screw 30 includes a screw shaft 31, a nut 32, a first rolling groove formed on the outer diameter surface of the screw shaft 31, and a screw shaft 31 formed on the inner diameter surface of the nut 32 (not shown). A second rolling groove facing one rolling groove, a rolling element rolling path formed between the first rolling groove and the second rolling groove, and a plurality of rolling elements loaded in the rolling element rolling path And rolling elements (balls). The lower end of the screw shaft 31 is fixed to the upper surface of the work feed table 34. Further, a motor 33 is connected to the screw shaft 31 so that the screw shaft 31 can rotate. The nut 32 has an outer diameter surface fixed to a bracket (not shown). When the screw shaft 31 is rotated by the rotational driving force applied from the motor 33, the screw shaft 31 reciprocates (vertically moves) in the vertical direction through the rolling of the rolling elements, and the work feed table 34 is not shown. It reciprocates (moves up and down) along the guide device.

In the present embodiment, the semiconductor ingot 50 is fixed to the slice base 36 by an adhesive member. The semiconductor ingot 50 is detachably attached to the lower part of the work feed table 34 via the slice base 36.
Here, in this embodiment, by controlling various motors, the wire bobbins 12A and 12B and the driving roller are driven synchronously to cause the fixed abrasive wire 10 to reciprocate at a preset wire traveling speed Vw. At this time, in the present embodiment, most of the fixed abrasive wire 10 is wound around the wire bobbin 12A with the wire bobbin 12A as the supply side and the wire bobbin 12B as the winding side. Then, in the wire bobbin 12A, for example, the fixed abrasive wire 10 is rotated 100 [m] and is rotated 90 [m]. On the other hand, the wire bobbin 12B is rotated in synchronism with the wire bobbin 12A, such as winding the fixed abrasive wire 10 100 [m] and feeding it 90 [m]. Thus, the fixed abrasive wire 10 is reciprocated and a new wire portion is supplied. That is, in this example, for each round trip, a new wire portion is added by 10 [m] to the wire row 20 contributing to cutting, and the wire portion used for cutting is 10 [m] by wire bobbin 12B. It will be rolled up.

  While the fixed abrasive wire 10 is reciprocatingly driven, the screw shaft 31 of the ball screw 30 is rotationally driven by the motor 33 to lower the work feed table 34 at a constant speed (for example, 0.80 [mm / min]). Accordingly, the semiconductor ingot 50 mounted on the work feed table 34 is pressed against the wire row 20 that reciprocates at the set wire travel speed Vw via the slice base 36. As shown in FIG. 3, the semiconductor ingot 50 pressed against the wire row 20 is cut at a plurality of locations at the same time by the wire row 20 arranged in parallel at a constant wire pitch (for example, 325 [μm]). In this way, a plurality of semiconductor ingots 50 are simultaneously cut at a constant pitch and processed into a plurality of wafers.

For this purpose, the fixed abrasive wire saw 1 includes a control unit 70 that controls operations of various motors, actuators, electric pumps, and the like, as shown in FIG.
The controller 70 controls the motors 24A and 24B and the drive motor of the drive roller 18A according to the set wire travel speed Vw. In this embodiment, detection information from a detector (not shown) that detects the current traveling speed of the fixed abrasive wire 10 and the state (rotational speed, etc.) of each motor, using the set wire traveling speed Vw as a target speed. Based on the above, each motor is feedback-controlled. Thereby, the wire traveling speed at the time of cutting the semiconductor ingot 50 is controlled to maintain the set target speed Vw.

  In the present embodiment, a semiconductor ingot formed from a semiconductor material or a semiconductor block formed from the ingot (hereinafter referred to as a semiconductor ingot without distinguishing both) is used as a cutting target. The controller 70 controls the wire traveling speed to a speed within the range of 100 [m / min] <Vw <400 [m / min] when the semiconductor ingot is cut.

  Here, when cutting a semiconductor ingot such as a polycrystalline silicon ingot, it is known that the hardness of the polycrystalline semiconductor ingot varies locally because the size of the crystal grains changes locally. In addition, it is also known that a polycrystalline semiconductor ingot generates wire blurring during cutting in the vicinity of inclusions such as silicon nitride mixed in the ingot during ingot growth.

  As a result of experiments, the inventors have found that when a polycrystalline silicon ingot is cut at the same wire traveling speed as when a conventional single crystal silicon ingot is cut, the number of wafer drops increases as the wire traveling speed increases. I found that I tend to do. On the other hand, it has been found that by reducing the wire traveling speed to lower than 400 [m / min], the number of wafer dropouts is reduced and the stable region is entered. However, when the wire traveling speed was 100 [m / min] or less, the cutting performance deteriorated, and the necessary cutting ability could not be obtained.

  For this reason, in this embodiment, when cutting a semiconductor ingot, particularly a polycrystalline ingot, the wire traveling speed Vw is set to a speed within a range of 100 [m / min] <Vw <400 [m / min]. To be controlled. In this speed range, it was confirmed that the number of wafer dropouts decreased most particularly in the range of 300 [m / min] or less. Therefore, when cutting the semiconductor ingot, it is more preferable to control the wire traveling speed Vw to a speed within the range of 100 [m / min] <Vw ≦ 300 [m / min].

  Further, the control unit 70 controls the actuators 26A and 26B in accordance with a preset wire tension F. In the present embodiment, the set wire tension F is set as a target tension, and based on detection information from a detector (not shown) that detects the current tension of the fixed abrasive wire 10 and the state of the actuator (pressing force, etc.). Feedback control of the actuator. Thereby, the wire tension at the cutting position (wire row 20) at the time of cutting the semiconductor ingot 50 is controlled to be the set target tension F.

Here, the tension of the wire row 20 when the semiconductor ingot 50 is cut changes according to the following equation (1) in accordance with the semiconductor ingot 50 being pressed against the wire row 20 at a constant speed.
Ftn = Ft1 + μFN1 + μFN2 +... ΜFN (n−1) + μFNn (1)
In the above equation (1), Ftn is the tension of the nth turn of the wire row 20. Ft1 is an initial tension before the semiconductor ingot 50 is pressed. μFN1, μFN2,..., μFN (n−1), μFNn respectively push the wire array 20 at a constant speed of the semiconductor ingot 50 of the first, second,. It is the tension that increases with the guess.

Since the tension of the wire row 20 continues to descend at a constant speed in a state where the semiconductor ingot 50 is pressed against the wire row 20, it continues to increase according to the above equation (1). Therefore, as shown in FIG. 4, the tension Ft2 after one turn after pressing the semiconductor ingot 50 becomes a tension obtained by adding the increased μFN1 to the initial tension Ft1 (Ft2 = Ft1 + μFN1).
Here, when the tension of the wire row 20 increases too much, the wire breakage occurs. On the other hand, if the tension of the wire row 20 is too low, the wobbling width (swell) of the wire when the semiconductor ingot 50 is cut increases, causing coalescence with adjacent wires and the number of wafer dropouts increases.

  In the present embodiment, when the wire diameter of the wire is φ120 [μm], the wire tension of 27 [N] or more is set as the initial tension Ft1 in consideration of the fluctuation width. And the tension | tensile_strength provided to the wire row | line | column 20 via tension roller 16A, 16B is controlled by control of actuator 26A, 26B by the control part 70, The tension | tensile_strength more than set 27 [N] is maintained. . The upper limit of the wire tension is determined by the strength of the wire and the device configuration.

As described above, according to the semiconductor ingot cutting method using the fixed abrasive wire saw 1 according to the present embodiment, the wire traveling speed Vw when cutting the semiconductor ingot 50 is set to 100 [m / min] <Vw <400 [m. / Min] to control the speed. Thereby, compared with the case where it cut | disconnects at the speed of 400 [m / min] or more of the past, the number of drop-off of a wafer can be reduced.
Further, the tension at the cutting position (wire array 20) of the fixed abrasive wire saw 1 when cutting the semiconductor ingot 50 is controlled to 27 [N] or more (2390 [N / mm ² ] or more) with a wire of φ120 [μm]. I tried to do it. Thereby, compared with the case where it controls to 27 [N] (less than 2390 [N / mm < ² >]), the fluctuation width of the wire at the time of a cutting | disconnection can be reduced.

(Modification)
In the embodiment described above, the configuration in which the semiconductor ingot 50 is pressed down from above the wire row 20 in the vertical direction has been described as an example, but the configuration is not limited thereto. The direction of the wire row 20 may be changed to another direction, and the semiconductor ingot 50 may be moved from another direction to be pressed in accordance with the direction.
In the above-described embodiment, the work feed table 34 has been described by taking as an example a configuration in which the ball screw 30 is driven up and down by a motor, but the present invention is not limited to this configuration.
For example, other configurations such as a configuration in which the work feed table 34 is linearly moved using a linear actuator to press the semiconductor ingot 50 against the wire row 20 may be employed.

Moreover, in the said embodiment, although the wire row | line | column 20 was reciprocated and demonstrated and demonstrated the example which cuts and cut | disconnects a to-be-processed object, not only this structure but one of the wire bobbins 12A and 12B is made into the wire delivery side, Other configurations may be employed, such as a configuration in which the other side is the wire winding side and the workpiece is cut and cut by running the wire in one direction.
Moreover, in the said embodiment, although two main rollers which comprise the wire row | line 20 were used, it is good not only as this structure but as a structure which uses three or more main rollers.

In the above-described embodiment, the configuration in which the motor 18A is driven as a driving roller out of the two main rollers 18A and 18B is described as an example, but the configuration is not limited thereto.
For example, the main roller may be rotatably provided, and other configurations such as a configuration in which only the motor that rotationally drives the wire bobbins 12A and 12B or a configuration in which all the main rollers are rotationally driven by the motor may be employed.

The above embodiments are preferable specific examples of the present invention, and various technically preferable limitations are given. However, the scope of the present invention is described in particular in the above description to limit the present invention. As long as there is no, it is not restricted to these forms. In the drawings used in the above description, for convenience of illustration, the vertical and horizontal scales of members or parts are schematic views different from actual ones.
Further, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

Hereinafter, based on FIG. 5, the Example using the fixed abrasive wire saw 1 of the said embodiment is described.
FIG. 5 is a diagram illustrating a relationship between the wire traveling speed based on the cutting test according to the example and the wafer dropout rate.
In this example, a polycrystalline silicon ingot (W: 156 [mm] × H: 156 [mm] × L: 250 [mm]) for a solar cell was employed as the semiconductor ingot 50. As the fixed abrasive wire 10, a wire (wire diameter φ130 [μm], average abrasive particle size 12 to 25 [μm], wire length 30 [km]) manufactured by Asahi Diamond Industry is used, and the wire pitch is 325 [ μm]. The wire traveling direction is set to reciprocating, the wire traveling speed is set in the range of 200 [m / min] to 1400 [m / min] in increments of 100 [m / min], and the wire tension is set to 32 [N]. The cutting test at each set speed was performed. The lowering speed of the work feed table 34 at the time of cutting was set to 0.8 [mm / min]. Moreover, the coolant made from Yushiro Chemical Industry was used as a processing liquid. Moreover, it cut | disconnected 3 times each with respect to the same wire travel speed.

  As a result of the cutting test under such measurement conditions, the test result shown in FIG. 5 was obtained as the relationship between the wire traveling speed and the wafer dropout rate (average value of three tests). In FIG. 5, “◯” indicates the average value at each measurement speed, and the “D” -shaped vertically extending bar line indicates the range of variation in the number of dropped wafers at each measurement speed.

Note that the drop-off number rate is obtained as follows. First, when cutting one or more silicon ingots, the number of slices per cut (one shot) is:
Number of slices = [(length in the direction perpendicular to the wire of the ingot) × (number of ingots per shot)] / [wire pitch]
The wafer drop rate is calculated as follows:
Wafer drop rate = [number of wafers dropped during slicing] / [number of slices]
Is required.

  As shown in FIG. 5, in the speed range of 600 [m / min] to 800 [m / min] that is generally used for cutting a single crystal silicon ingot, the drop-off number rate is about 0.5 to 2. It is 0 [%], and it can be seen that there is a variation in the dropout rate at the same travel speed. On the other hand, at a speed band of less than 400 [m / min], the wafer drop rate is stable at about 0.2 [%] or less, and a speed band of 600 [m / min] to 800 [m / min]. It can be seen that the ratio of the number of dropped wafers is lower than that in FIG. In addition, it can be seen that the dropout rate is stable without fluctuations.

Further, when the wire traveling speed is made higher than 800 [m / min], the wafer drop rate is about 0.5 to 3.0 [%] up to a speed band of 1200 [m / min]. In comparison with the speed band of less than 400 [m / min], the variation in the number of dropped wafers is large and the number of dropped sheets is high.
As described above, in the cutting process of the semiconductor ingot using the fixed abrasive wire saw, the wire traveling speed Vw is set to 100 [m / min] <Vw <400 [m even if the ingot is polycrystalline. / Min], it is possible to reduce the wafer drop-off rate as compared with the conventional processing at a wire traveling speed of 400 [m / min] or more.

DESCRIPTION OF SYMBOLS 1 Fixed abrasive wire saw 10 Fixed abrasive wire 12A, 12B Wire bobbin 14A-14D Guide roller 16A, 16B Tension roller 18A, 18B Main roller 20 Wire row 22 Coolant nozzle 24A, 24B, 33 Motor 26A, 26B Actuator 30 Ball screw 34 Workpiece Feed table 36 Slice base 50 Semiconductor ingot 70 Control unit

Claims (6)

In a cutting method of running a fixed abrasive wire having a plurality of abrasive grains fixed on its surface in the longitudinal direction and cutting the semiconductor ingot with the fixed abrasive wire that has been run,
Cutting the semiconductor ingot, wherein the wire traveling speed Vw of the fixed abrasive wire saw when cutting the semiconductor ingot is set to a speed within a range of 100 [m / min] <Vw <400 [m / min]. Method. ^{2. The} method for cutting a semiconductor ingot according to claim 1, wherein the tension of the fixed abrasive wire at the cutting position is controlled to 2390 [N / mm ² ] or more with respect to the diameter of the wire to be used. The fixed abrasive wire saw has a plurality of wire rows configured by winding the fixed abrasive wire around a plurality of rollers arranged to face each other in parallel with a fixed pitch.
3. The semiconductor ingot according to claim 1, wherein the semiconductor ingot is configured such that the plurality of wire rows travel in a longitudinal direction and the plurality of wire rows thus traveled can be cut simultaneously. Cutting method. A fixed abrasive wire saw in which a fixed abrasive wire having a plurality of abrasive grains fixed on its surface is run in its longitudinal direction, and the semiconductor abrasive is cut with the fixed abrasive wire that has been run,
A fixed-abrasive wire saw comprising a control unit that controls the wire traveling speed Vw when cutting the semiconductor ingot to a speed within a range of 100 [m / min] <Vw <400 [m / min].   A wafer manufactured using the cutting method according to any one of claims 1 to 3.   A wafer manufactured using the wire saw according to claim 4.

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