Method for slicing semiconductor ingot

Abstract

Provided is a method for slicing a semiconductor ingot that, without modifying the configuration of a wire saw device, is capable of suppressing deterioration in flatness of a wafer caused by torsion of a wire. A wire is stretched between a first reel 10A, which is a new wire feed reel, and a second reel 10B, which is an old wire collection reel, with main rollers 30A-C disposed therebetween. Next, before a slicing step, a no-load running step is performed for sending out a prescribed length of the wire from the first reel 10A and winding the wire around the second reel 10B. Next, the slicing step for slicing a semiconductor ingot is performed by causing the wire to reciprocate between the second reel 10B and the first reel 10A while using the second reel 10B as a new wire feed reel and the first reel 10A as an old wire collection reel. The wire wound around the second reel 10B in the no-load running step is gradually unwound and returned to the first reel 10A.

Description

Methods for slicing semiconductor ingots

[0001] The present invention relates to a method for slicing semiconductor ingots using a wire saw device.

[0002] Semiconductor wafers are manufactured by slicing semiconductor ingots made of silicon, compound semiconductors, and other materials. In recent years, the mainstream method for slicing ingots has become a wire saw that cuts multiple semiconductor wafers simultaneously.

[0003] Referring to Figure 1, a typical wire saw device 100 will be described. The wire saw device 100 mainly consists of a first reel 10A, a second reel 10B, a first guide roller 20A, a second guide roller 20B, first to third main rollers 30A, 30B, 30C, and an ingot holding mechanism 50. The wire 40 drawn from the first reel 10A, which serves as a new wire supply reel, is guided by the first guide roller 20A and wound spirally over the first to third main rollers 30A, 30B, 30C multiple times, forming a group of wires 42 arranged in parallel along the axial direction of each main roller between the first main roller 30A and the second main roller 30B. The wire 40 drawn from the first to third main rollers 30A, 30B, 30C is guided by the second guide roller 20B and wound onto the second reel 10B, which serves as an old wire retrieval reel. In this way, the wire 40 is stretched between the first reel 10A, which serves as the new wire supply reel, and the second reel 10B, which serves as the old wire retrieval reel.

[0004] In the slicing process, while lowering the semiconductor ingot I held by the ingot holding mechanism 50 from above the wire group 42 and pushing it into the wire group 42, the wire 40 is reciprocally run between the first reel 10A and the second reel 10B. In the loose abrasive grain method, the wire 40 is reciprocally run while continuously supplying a slurry containing abrasive grains to the wire group 42. In the fixed abrasive grain method, the wire 40 with abrasive grains fixed on its surface is reciprocally run while continuously supplying a coolant不含 abrasive grains to the wire group 42. Thus, by the cutting action of the abrasive grains, the semiconductor ingot I is sliced by the wire group 42 into a plurality of semiconductor wafers. At that time, the wire return amount is set shorter than the wire feed amount per reciprocation. For this reason, the wire (new wire) wound around the first reel 10A is gradually wound around the second reel 10B while forming the wire group 42. That is, the first reel 10A functions as a new wire supply reel, and the second reel 10B functions as an old wire recovery reel.

[0005] Here, due to the wire 40 being spirally wound around the first to third main rollers 30A, 30B, 30C, the wire (new wire) 40 supplied from the first reel 10A is twisted in the process of forming the wire group 42. When the wire 42 is twisted, the wire 42 wears uniformly in the circumferential direction in its vertical cross section, and uneven wear of the wire is suppressed. For this reason, it is not necessary to completely eliminate the twist of the wire.

[0006] On the other hand, when the twist of the wire becomes excessive, the wire breaks, and the manufacturing efficiency of the semiconductor wafer decreases. As prior art documents paying attention to this problem, there are Patent Document 1 and Patent Document 2.

[0007] Patent Document 1 (see particularly FIG. 1) describes that after winding the wire spirally from the center of the main roller toward one end, the wire drawn out from one end is once returned to the guide roller, and then the wire is wound spirally from the center of the main roller toward the other end again. This is to cancel the twist by providing a portion where the wire rotates clockwise and a portion where the wire rotates counterclockwise in the main roller.

[0008] Patent Document 2 describes monitoring the twisting of a wire and moving part or all of the wire in the axial direction of the main roller to alleviate the monitored twisting state of the wire. Monitoring is performed using a camera mounted to allow confirmation of the wire condition, and the rotational speed is measured after finding characteristic parts of the fixed abrasive wire. Furthermore, the method of moving the wire is described as moving the main roller itself in the axial direction and moving a sub-roller positioned below the main roller in the axial direction.

[0009] Japanese Patent Publication No. 2004-314214 Japanese Patent Publication No. 2012-250329

[0010] However, the technology described in Patent Document 1 requires the addition of multiple guide rollers, necessitating significant modifications to the wire saw apparatus. Furthermore, because the wire arrangement direction is switched at the center of the main roller, it is not possible to cut long ingots, leading to a significant deterioration in yield (the number of wafers obtained in one slicing process).

[0011] Furthermore, as described in Patent Document 2, significant modifications to the wire saw device are necessary, including the addition of a main roller movement mechanism and a sub-roller and its movement mechanism.

[0012] Furthermore, the inventors have identified a problem caused by wire twisting that is not recognized in Patent Documents 1 and 2. Specifically, as will be described in detail later with reference to Figure 2, during the reciprocating movement of the wire, the twisting of the wire depends on the direction of the wire arrangement on the main roller, and is in opposite directions during wire feeding and wire return. Since the wire return amount is set to be shorter than the wire feed amount per reciprocation, unidirectional twisting accumulates in the wire as the number of reciprocations increases. It has been found that this accumulation of twisting causes deterioration in flatness in the resulting semiconductor wafer, such as a deterioration of warp, which is an indicator of the waviness shape of the cut surface, and the observation of warping along the cutting direction in the shape map.

[0013] In view of the above issues, the present invention aims to provide a method for slicing semiconductor ingots that can suppress the deterioration of wafer flatness caused by wire twisting without modifying the configuration of the wire saw apparatus.

[0014] To solve the above problems, the inventors conducted diligent research and obtained the following findings. Specifically, after the wire is stretched between the new wire supply reel and the old wire recovery reel, before the slicing process, a dry run process is performed in which a predetermined length of wire is fed from the new wire supply reel and wound onto the old wire recovery reel via the main roller, thereby imparting a slight twist to the wire. Then, the conventional old wire recovery reel is used as the new wire supply reel, and the slicing process is performed using the conventional new wire supply reel as the old wire recovery reel. In the slicing process, the wire wound onto the old wire recovery reel (operational new wire supply reel) by the dry run process is gradually wound back onto the new wire supply reel (operational old wire recovery reel). In this process, a twist in the opposite direction to the twist previously imparted in the dry run process accumulates, so during the slicing process, the twist in one direction cancels out, and a slight twist in the other direction is imparted. As a result, the effects of twisting during the slicing process are mitigated compared to conventional methods, making it possible to suppress the deterioration of wafer flatness caused by wire twisting.

[0015] Based on the above findings, the gist of the present invention is as follows: [1] A method for slicing a semiconductor ingot using a wire saw device, comprising: a preparation step for the wire saw device, in which a wire wound on a first reel is pulled out from the first reel, wound spirally multiple times over a pair of rollers placed side by side so that their axial directions are parallel to each other, forming a group of wires arranged in parallel along the axial directions of the pair of rollers between the pair of rollers, and then pulled out from the pair of rollers and wound onto a second reel, so that the wire is stretched between the first reel and the second reel via the pair of rollers; and then, with the semiconductor ingot separated from the group of wires, a dry run step in which the wire is fed out from the first reel by a predetermined length and wound onto the second reel via the pair of rollers, A method for slicing a semiconductor ingot, comprising: a slicing step in which the semiconductor ingot is pushed against the wire group while being lowered from above the wire group, the wire is run back and forth between the second reel and the first reel, and the amount of wire returned to the second reel is set to be shorter than the amount of wire fed from the second reel per reciprocating step, so that the wire wound on the second reel in the dry-running step is gradually wound back onto the first reel, and in the process the semiconductor ingot is sliced ​​by the wire group.

[0016] [2] The semiconductor ingot slicing method according to [1] above, wherein the wire is a fixed abrasive wire.

[0017] According to the semiconductor ingot slicing method of the present invention, it is possible to suppress the deterioration of wafer flatness caused by wire twisting without modifying the configuration of the wire saw apparatus.

[0018] This is a schematic perspective view of the wire saw device 100 used in the conventional example and the embodiment of the present invention. This is a schematic view of the first to third main rollers 30A, 30B, and 30C of the wire saw device 100 as seen from above, and is a diagram for explaining the twisting that occurs in the wire 40. (A) and (B) are diagrams of conventional wire operation. (A) to (C) are diagrams of wire operation according to the present invention. These are shape maps of silicon wafers obtained by slicing the conventional example (comparative example) and the inventive example.

[0019] The following describes a method for slicing a semiconductor ingot according to one embodiment of the present invention. The semiconductor ingot may be made of any semiconductor such as silicon, germanium, or gallium arsenide, and may be either a single-crystal ingot or a polycrystalline ingot, but a single-crystal silicon ingot is particularly preferred. The diameter, conductivity type, and resistivity of the semiconductor ingot are also not limited.

[0020] [Configuration of Wire Saw Device 100] Referring to Figure 1, a wire saw device 100 used in one embodiment of the present invention will be described. The wire saw device 100 mainly consists of a first reel 10A, a second reel 10B, a first guide roller 20A, a second guide roller 20B, first to third main rollers 30A, 30B, 30C, and an ingot holding mechanism 50. The wire 40 drawn out from the first reel 10A, which serves as a new wire supply reel, is guided by the first guide roller 20A and wound spirally over the first to third main rollers 30A, 30B, 30C multiple times, forming a group of wires 42 arranged in parallel along the axial direction of each main roller between the first main roller 30A and the second main roller 30B. The wire 40 drawn out from the first to third main rollers 30A, 30B, and 30C is guided by the second guide roller 20B and wound onto the second reel 10B, which serves as the old wire retrieval reel. In this way, the wire 40 is stretched between the first reel 10A, which serves as the new wire supply reel, and the second reel 10B, which serves as the old wire retrieval reel. In this specification, the wire supplied from the reel is referred to as the "new wire," and the wire retrieved onto the reel is referred to as the "old wire."

[0021] Figure 1 shows an example in which three main rollers are arranged as the first to third main rollers 30A, 30B, and 30C, but the number of main rollers is not particularly limited as long as there are multiple (i.e., two or more) rollers. It is sufficient to have a pair of rollers (the first main roller 30A and the second main roller 30B in Figure 1) placed side by side so that their axial directions are parallel to each other. Note that the multiple main rollers (the first to third main rollers 30A, 30B, and 30C in Figure 1) are arranged with their ends aligned so that their axial directions are parallel to each other.

[0022] Multiple grooves are formed at a constant pitch on the surfaces of the first to third main rollers 30A, 30B, and 30C. When the wire 40 is fitted into these grooves, the wire 40 is wound spirally along the grooves, across the first to third main rollers 30A, 30B, and 30C multiple times, thereby forming the wire group 42.

[0023] In the slicing process, the semiconductor ingot I, held by the ingot holding mechanism 50, is lowered from above the wire group 42 and pushed against the wire group 42, while the wire 40 is made to reciprocate between the first reel 10A and the second reel 10B. Motors (not shown) are attached to the first reel 10A and the second reel 10B, and the first reel 10A and the second reel 10B are rotationally driven by these motors, causing the wire 40 to reciprocate between the first reel 10A and the second reel 10B. The first guide roller 20A and the second guide roller 20B are driven rollers. The first to third main rollers 30A, 30B, and 30C may be driven rollers in which some rollers (for example, the third main roller 30C) are rotationally driven by a motor, with the remaining rollers being driven rollers, or all rollers may be driven rollers.

[0024] In the free abrasive method, a slurry containing abrasive particles is continuously supplied to the wire group 42 from a nozzle (not shown) while the wire 40 is moved back and forth. In the fixed abrasive method, a coolant without abrasive particles is continuously supplied to the wire group 42 while the wire 40, on which abrasive particles are fixed to the surface, is moved back and forth. In this way, the semiconductor ingot I is sliced ​​by the wire group 42 through the cutting action of the abrasive particles, resulting in multiple semiconductor wafers.

[0025] [Wire Twisting] In the example shown in Figure 1, the arrangement direction of the wires 40 in the main roller is from the right side of the paper to the left side (from the front to the back). Here, the wires 40 experience a twist in a predetermined rotational direction, depending on the arrangement direction of the wires 40 in the main roller. The twisting that occurs in the wires 40 will be explained with reference to Figure 2.

[0026] In the wire group 42 formed between the first main roller 30A and the second main roller 30B, each wire 40 is perpendicular to the axial direction of the main roller and parallel to each other. However, in the process of returning from the second main roller 30B through the third main roller 30C to the first main roller 30A, the wire 40 moves slightly diagonally. This is because, when returning the wire 40 to the first main roller 30A, the wire 40 is returned to the groove adjacent to the groove in which it was fitted in the previous winding. In the wire arrangement direction shown in Figure 2, a counterclockwise twist occurs in the wire 40 when viewed from the direction of wire travel. That is, when feeding the wire 40 from the first reel 10A to the second reel 10B, a counterclockwise twist (left rotation in Figure 2) occurs when viewed from the direction of feeding the wire 40, and when returning the wire 40 from the second reel 10B to the first reel 10A, a counterclockwise twist (right rotation in Figure 2) occurs when viewed from the direction of return of the wire 40.

[0027] [Conventional wire operation] Here, we will explain conventional wire operation with reference to Figures 3(A) and 3(B).

[0028] First, in the preparation step shown in Figure 3(A) (see also Figure 1), the wire 40 wound on the first reel 10A is pulled out from the first reel 10A, wound spirally multiple times over the first to third main rollers 30A, 30B, and 30C to form a wire group 42, and then pulled out again from the first to third main rollers 30A, 30B, and 30C and wound onto the second reel 10B. In this way, the wire 40 is stretched between the first reel 10A and the second reel 10B via the first to third main rollers 30A, 30B, and 30C. Typically, the first reel 10A is a new reel wound with new wire. The second reel 10B is empty, with no old wire recovered. At this stage, no twisting has occurred in the wire 40.

[0029] Next, in the semiconductor ingot slicing process shown in Figure 3(B) (see also Figure 1), the semiconductor ingot I, held by the ingot holding mechanism 50, is pushed against the wire group 42 while being lowered from above, and the wire 40 is moved back and forth between the first reel 10A and the second reel 10B. At this time, the amount of wire returned per reciprocation is set to be shorter than the amount of wire fed. As a result, the wire (new wire) wound on the first reel 10A is gradually wound onto the second reel 10B while forming the wire group 42, and in the process the semiconductor ingot I is sliced ​​by the wire group 42. In other words, the first reel 10A functions as a new wire supply reel, and the second reel 10B functions as an old wire recovery reel.

[0030] In this case, since the wire return amount is shorter than the wire feed amount per round trip, the leftward twist generated when the wire 40 is fed cannot be completely offset by the rightward twist generated when the wire 40 is returned. As a result, as the number of round trips of the wire 40 increases, a large amount of leftward twist accumulates in the wire 40 at the first to third main rollers 30A, 30B, 30C and the second reel 10B. This accumulation of twist causes deterioration in flatness in the resulting semiconductor wafer, such as a worsening of the warp, which is an indicator of the waviness shape of the cut surface, or the observation of warping along the cutting direction in the shape map.

[0031] [Wire operation according to the present invention] Therefore, the wire operation according to the present invention will be explained with reference to Figures 4(A) to 4(C).

[0032] First, the preparation steps shown in Figure 4(A) are the same as those shown in Figure 3(A), so we will use the explanation from Figure 3(A) for this explanation.

[0033] Next, the dry run process shown in Figure 4(B) (see also Figure 1) is a characteristic process of the present invention. With the semiconductor ingot I separated from the wire group 42, a predetermined length of wire 40 is fed from the first reel 10A and wound onto the second reel 10B via the first to third main rollers 30A, 30B, and 30C. Typically, the entire amount of new wire wound on the first reel 10A is wound onto the second reel 10B, leaving the first reel 10A empty and free of new wire, while the second reel 10B has recovered all of the old wire. However, the "predetermined length" of wire 40 fed from the first reel 10A to the second reel 10B is not limited to the entire amount of wire wound on the first reel 10A, but should be greater than or equal to the length of wire required to slice one semiconductor ingot. The dry run process is performed before the slicing process to impart a slight leftward twist to the wire 40. Furthermore, since the idle running process does not involve running the wire 40 back and forth, but simply runs the wire 40 once from the first reel 10A to the second reel 10B, the leftward rotational twist imparted by the idle running process is smaller than the leftward rotational twist accumulated after the conventional slicing process shown in Figure 3(B).

[0034] Next, in the semiconductor ingot slicing process shown in Figure 4(C) (see also Figure 1), the semiconductor ingot I, held by the ingot holding mechanism 50, is pushed against the wire group 42 while being lowered from above, and the wire 40 is run back and forth between the second reel 10B and the first reel 10A. At this time, the amount of wire returned per reciprocation is set to be shorter than the amount of wire fed. As a result, the wire wound onto the second reel 10B during the dry run process is gradually wound back onto the first reel 10A, and in the process the semiconductor ingot I is sliced ​​by the wire group 42. In other words, the second reel 10B functions as a new wire supply reel, and the first reel 10A functions as an old wire retrieval reel.

[0035] In this case, contrary to the slicing process in Figure 3(B), when the wire 40 is fed from the second reel 10B to the first reel 10A, a right-handed twist occurs, and when the wire 40 is returned from the first reel 10A to the second reel 10B, a left-handed twist occurs. Since the amount of wire returned per round trip is shorter than the amount of wire fed, the right-handed twist that occurs when the wire 40 is fed cannot be completely offset by the left-handed twist that occurs when the wire 40 is returned. As a result, as the number of round trips of the wire 40 increases, a large amount of right-handed twist accumulates in the wire 40 at the first to third main rollers 30A, 30B, 30C and the first reel 10A. However, the wire 40 is initially given a small amount of left-handed twist by the dry-running process. Therefore, during the slicing process, the left-rotational twist pre-impregnated during the idle run cancels out the right-rotational twist generated during the slicing process. As a result, the right-rotational twist accumulated at the end of the slicing process is smaller than the left-rotational twist accumulated at the end of the conventional slicing process shown in Figure 3(B). Consequently, the effect of twisting during the slicing process is mitigated compared to conventional methods, making it possible to suppress the deterioration of wafer flatness caused by wire twisting.

[0036] [Slicing Method] In the semiconductor ingot slicing method according to one embodiment of the present invention, the slicing method is not limited and may be either a free abrasive method or a fixed abrasive method. In the free abrasive method, a slurry containing abrasive grains is continuously supplied to the wire group 42 while the wire 40 is moved back and forth. In the fixed abrasive method, a coolant without abrasive grains is continuously supplied to the wire group 42 while the wire 40, on which abrasive grains are fixed to the surface, is moved back and forth. In this way, the semiconductor ingot I is sliced ​​by the wire group 42 by the cutting action of the abrasive grains, resulting in multiple semiconductor wafers. However, the semiconductor ingot slicing method according to one embodiment of the present invention shows particularly remarkable effects when a fixed abrasive method is adopted.

[0037] This is because, in the fixed abrasive method, the price of wire is significantly higher than in the free abrasive method, so the amount of wire used to slice a single semiconductor ingot must be kept to a minimum. In the fixed abrasive method, in order to reduce the amount of wire used, the difference between the amount of wire fed and the amount of wire returned per reciprocation is made small, and new wire is supplied little by little. As a result, the number of reciprocations on the main roller per unit length increases, and twisting tends to accumulate. In other words, if the present invention is not adopted, the twisting of the wire has a significant impact on the deterioration of wafer flatness. To put it another way, the effect of suppressing the deterioration of wafer flatness according to the present invention is remarkably obtained.

[0038] In the slicing process, the slicing conditions, such as the amount of wire fed and retracted per round trip, the time required for one round trip, the wire tension, and the descent speed of the semiconductor ingot relative to the wire group, are not particularly limited and can follow standard methods. The composition, temperature, and supply flow rate of the slurry or coolant are also not particularly limited and can follow standard methods.

[0039] Using the wire saw apparatus shown in Figure 1, silicon ingots were sliced ​​using the wire operation shown in Figures 3(A) and (B) in the conventional example (comparative example), and using the wire operation shown in Figures 4(A) to (C) in the inventive example. The diameter of the silicon ingot used was approximately 201 mm in both the conventional example (comparative example) and the inventive example, and the crystal length was approximately 155 mm in the conventional example (comparative example) and approximately 145 mm in the inventive example. In the wire saw apparatus, the distance between the axes of the first main roller and the second main roller was set to 560 mm. The slicing method was a fixed abrasive method, and a wire with a diameter of 100 μm in the cross-section perpendicular to the extension direction, with abrasive grains of 5 to 10 μm (average grain size: 8 μm) fixed to it, was used as the wire, and the groove pitch of the main roller was set to 940 μm to form a wire group. The length of the wire wound on the main roller was approximately 900 m. During slicing, the wire was moved back and forth while a coolant without abrasive grains was supplied to the wire group.

[0040] In the slicing process, the wire feed amount per round trip was set to approximately 1260 m, the wire return amount to approximately 1240 m, and the time required for one round trip was set to 180 seconds. In this case, the average wire travel speed was approximately 833 m / min, and 20 m of new wire was supplied in one round trip in 180 seconds (new wire supply amount: approximately 6.7 m / min). The wire tension was set to 22 N. The number of silicon wafers obtained from one silicon ingot was 162 in the conventional example (comparative example) and 150 in the inventive example. In this case, the length of wire required to cut one silicon ingot (new wire supply amount) was approximately 2.8 km.

[0041] In the conventional example (comparative example), the first reel was used as a new wire supply reel and the second reel as an old wire retrieval reel, and the silicon ingot was sliced ​​while the wire was run back and forth. In the inventive example, a dry run process was performed in which the wire was fed out from the first reel for approximately 5 km and wound onto the second reel via the main roller, and then the silicon ingot was sliced ​​while the wire was run back and forth, with the second reel used as a new wire supply reel and the first reel as an old wire retrieval reel.

[0042] In each of the conventional example (comparative example) and the inventive example, the Warp of all the obtained silicon wafers was measured using a flatness measuring instrument. The results are shown in Table 1. Also, in each of the conventional example (comparative example) and the inventive example, the shape maps of representative silicon wafers obtained at the upstream side, the central part, and the downstream side in the wire array direction are shown in FIG. 5.

[0043]

[0044] As is clear from Table 1, in the conventional example (comparative example), the average value of Warp was large and the variation was also large, whereas in the inventive example, the average value of Warp was small and the variation was also small. Also, as is clear from FIG. 5, in the conventional example (comparative example), a large warp can be confirmed along the slice direction, whereas in the inventive example, the warp was small. From this, it can be understood that according to the present invention, it is possible to suppress the deterioration of the flatness of the wafer due to the twist of the wire.

[0045] The slicing method of the semiconductor ingot according to the present invention can be applied to the manufacture of semiconductor wafers.

[0046] Also, the slicing method of the semiconductor ingot according to the present invention can improve the yield of the semiconductor wafer by improving the flatness of the sliced semiconductor wafer. The improvement in yield enables higher manufacturing efficiency of semiconductor products to produce more high-quality products, contributing to the promotion of technological innovation and the sustainable development of the industry. The improvement in yield also contributes to the efficient use of resources by reducing the waste of materials consumed in the manufacturing process of semiconductor products. Furthermore, the improvement in yield reduces the waste of energy consumed in the manufacturing process of semiconductor products, and as a result, also contributes to the reduction of greenhouse gas emissions.

[0047] That is, the present invention can contribute to, for example, "Goal 9: Industry, Innovation, and Infrastructure Building", "Goal 12: Ensuring Sustainable Consumption and Production", and "Goal 13: Combating Climate Change" in the Sustainable Development Goals (SDGs).

[0048] 100 Wire saw device 10A First reel (new wire supply reel → old wire retrieval reel) 10B Second reel (old wire retrieval reel → new wire supply reel) 20A First guide roller 20B Second guide roller 30A First main roller 30B Second main roller 30C Third main roller 40 Wire 42 Wire group 50 Ingot holding mechanism I Semiconductor ingot

Claims

1. A method for slicing a semiconductor ingot using a wire saw device, comprising: a preparation step for the wire saw device, in which a wire wound on a first reel is pulled out from the first reel, wound spirally multiple times across a pair of rollers placed side by side so that their axial directions are parallel to each other, forming a group of wires arranged in parallel along the axial directions of the pair of rollers between the pair of rollers, and then pulled out from the pair of rollers and wound onto a second reel, so that the wire is taut between the first reel and the second reel via the pair of rollers; and then, with the semiconductor ingot separated from the group of wires, a dry run step in which the wire is fed out from the first reel by a predetermined length and wound onto the second reel via the pair of rollers; A method for slicing a semiconductor ingot, comprising: a slicing step in which the semiconductor ingot is pushed against the wire group while being lowered from above the wire group, the wire is run back and forth between the second reel and the first reel, and the amount of wire returned to the second reel is set to be shorter than the amount of wire fed from the second reel per reciprocating step, so that the wire wound on the second reel in the dry-running step is gradually wound back onto the first reel, and in the process the semiconductor ingot is sliced ​​by the wire group.

2. The method for slicing a semiconductor ingot according to claim 1, wherein the wire is a fixed abrasive wire.

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