A square process of a single crystal silicon rod

Abstract

The application provides a square cutting process of a single crystal silicon rod, which comprises the following steps: reverse cutting is performed on one end of the single crystal silicon rod in the axial direction; and forward cutting is performed on the other end of the single crystal silicon rod in the axial direction until the edge skin is completely removed. The application has the beneficial effect of adding a reverse cutting process, forming an enlarged redundancy on the end of the single crystal silicon rod which is subjected to reverse cutting by amplification processing, and then performing forward cutting. In the forward cutting process, the single crystal silicon rod is first cut to a set square size and then amplified, so that the forward cutting seam coincides with the reverse cutting seam until the cutting is completed. The collapse at the end of the single crystal silicon rod is translated to the middle of the single crystal silicon rod and located on the enlarged redundancy. In the subsequent grinding process, the enlarged redundancy with the collapse is ground and removed, thereby improving the square cutting quality of the single crystal silicon rod.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic technology, and in particular relates to a squaring process for monocrystalline silicon rods. Background Technology

[0002] With increasing societal emphasis on and openness to the use of green and renewable energy, photovoltaic technology is receiving growing attention and development. In the field of photovoltaic solar power generation, solar cells are made from high-quality silicon wafers. The current silicon wafer manufacturing process generally involves first squaring a cylindrical silicon rod using a squaring machine, followed by grinding, rounding, and polishing; finally, a slicing machine is used to slice the squared silicon rod.

[0003] In existing silicon rod squaring operations, the cutting guide wheel drives the cutting line to cut from the head of the silicon rod along its length and exit from the tail. Throughout the cutting process, the cutting guide wheel is positioned using the same cutting dimension. The cut-off portion of the silicon rod is recycled as edge trimming. Due to the weight of the edge trimming, the exit point at the tail of the silicon rod is prone to edge chipping, such as... Figure 1 As shown, this affects the squaring quality of the silicon rod, thus failing to guarantee product quality. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a squaring process for monocrystalline silicon rods, effectively solving the technical problem of edge chipping during the squaring process of monocrystalline silicon rods and overcoming the shortcomings of existing technologies.

[0005] The technical solution adopted in this invention is: a squaring process for a single-crystal silicon rod, comprising the following steps:

[0006] One end of the single-crystal silicon rod is cut in the reverse direction along the axial direction;

[0007] The other end of the single-crystal silicon rod is cut along the axial direction until the edge skin is completely removed.

[0008] Optionally, during the reverse cutting process, cutting is performed at a first cutting speed V1, the maximum edge thickness of the reverse cut is less than the maximum edge thickness of the forward cut, an amplified redundancy is formed at one end of the single crystal silicon rod where the reverse cut is performed, and the cutting distance of the reverse cut is D1.

[0009] Optionally, the amplification size of the amplification redundancy is set to 0.5 to 1.5 mm.

[0010] Optionally, the cutting distance D1 of the reverse cut is greater than the maximum width of the bow of the cutting line.

[0011] Optionally, the forward cutting includes the following steps:

[0012] The cutting is performed at a second cutting speed V2, and the cutting distance of the cutting is D2.

[0013] The middle section is cut at a third cutting speed V3, and the cutting distance of the middle section is D3;

[0014] The cutting is performed at a fourth cutting speed V4, and the cutting distance of the cutting is D4.

[0015] Optionally, during the infeed cutting and middle cutting processes, cutting is performed with a set square root dimension, and during the outfeed cutting process, enlarged cutting is performed so that the cutting line enters the cutting line seam of the reverse cutting, and the enlarged cutting forms a bevel on the surface of the single crystal silicon rod.

[0016] Optionally, after the cutting is completed, a back cut is performed at a fifth cutting speed V5, with a back cut distance of D5.

[0017] Optionally, after completing the back cut, the blade is fired again at a sixth cutting speed V6, with a firing distance of D6.

[0018] Optionally, the first cutting speed V1, the fourth cutting speed V4, and the sixth cutting speed V6 are the same, the fifth cutting speed V5 is greater than the third cutting speed V3, the third cutting speed V3 is greater than the second cutting speed V2, and the second cutting speed V2 is greater than the first cutting speed V1.

[0019] Optionally, the cutting distance D1 for the reverse cutting is set to 0 to 8% of the length of the single-crystal silicon rod, the cutting distance D2 for the infeed cutting is set to 0 to 6% of the length of the single-crystal silicon rod, the cutting distance D3 for the middle cutting is set to 0 to 86% of the length of the single-crystal silicon rod, the cutting distance D4 for the outfeed cutting is set to 0 to 10% of the length of the single-crystal silicon rod, the cutting distance D5 for the backcut is set to 0 to 3% of the length of the single-crystal silicon rod, and the outfeed distance D6 for the second outfeed cutting is set to 0 to 6% of the length of the single-crystal silicon rod.

[0020] The advantages and positive effects of this invention are as follows: By adopting the above technical solution, a reverse cutting process is added. Through amplification processing, an amplified redundancy is formed at one end of the monocrystalline silicon rod that is reverse-cut. Then, forward cutting is performed. In the forward cutting process, cutting is first performed with a set square root size, and then amplified cutting is performed to make the forward cutting seam coincide with the reverse cutting seam until the cutting is completed. The chipping at the end of the monocrystalline silicon rod is shifted to the middle of the monocrystalline silicon rod and located on the amplified redundancy. In the subsequent grinding process, the amplified redundancy with chipping is ground away, which improves the square root quality of the monocrystalline silicon rod and ensures product quality. The addition of back cutting in the forward cutting process effectively buffers the cutting wire bow and reduces the risk of wire breakage. Attached Figure Description

[0021] The above and other objects, features, and advantages of the present invention will become more apparent from the more detailed description of the embodiments of the invention in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same parts or steps.

[0022] Figure 1 This is a schematic diagram illustrating the chipping and breakage of a monocrystalline silicon rod during normal squaring and cutting using existing technology.

[0023] Figure 2 This is a schematic diagram of the squaring process of a single-crystal silicon rod according to an embodiment of the present invention.

[0024] Figure 3 This is a flowchart illustrating the squaring process of a single-crystal silicon rod according to an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram showing the enlarged redundancy of a single-crystal silicon rod using a square root process according to an embodiment of the present invention.

[0026] Figure 5 This is a flowchart of the forward cutting process of a single crystal silicon rod according to an embodiment of the present invention.

[0027] 1. Single-crystal silicon rod 2. Bottling 3. Magnification redundancy Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0030] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0031] When using expressions such as "at least one of A, B, and C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C. Similarly, when using expressions such as "at least one of A, B, or C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C.

[0032] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this disclosure.

[0033] like Figure 2 and Figure 3 As shown, an embodiment of the present invention provides a squaring process for a monocrystalline silicon rod, comprising: loading the monocrystalline silicon rod 1 onto a squaring worktable; using a positioning device to move the cutting guide wheel so that the cutting line is located at one end of the monocrystalline silicon rod 1 for reverse cutting dimension positioning; the cutting line is reverse-cut along the axial direction of the monocrystalline silicon rod 1, and then the cutting line is quickly retracted and reset; after completing the reverse cutting, the positioning device is used to move the cutting guide wheel so that the cutting line is located at the other end of the monocrystalline silicon rod 1 for forward cutting dimension positioning; the cutting line is forward-cut along the axial direction of the monocrystalline silicon rod 1 until the edge skin is completely removed. The specific locations of the forward and reverse cutting are not limited. For example, reverse cutting can be performed along the axial direction at the tail end of the monocrystalline silicon rod, and forward cutting can be performed along the axial direction at the head end. Alternatively, reverse cutting can be performed at the head end of the monocrystalline silicon rod, and forward cutting can be performed along the axial direction at the tail end. By first cutting in the reverse direction and then cutting in the forward direction, the exit position of the cutting line is shifted to the middle of the monocrystalline silicon rod 1, thereby shifting the chipping at the end of the monocrystalline silicon rod 1 towards the middle of the monocrystalline silicon rod 1.

[0034] Specifically, such as Figure 4As shown, during the reverse cutting process, cutting is performed at a first cutting speed V1. The maximum thickness of the edge material during reverse cutting is less than the maximum thickness during forward cutting, resulting in an amplified redundancy 3 at the reverse-cut end of the monocrystalline silicon rod. When positioning the cutting dimensions, the cutting depth of the reverse cutting is less than the cutting depth of the forward cutting. That is, during reverse cutting, the depth of the cut edge material is smaller, and the side length of the square rod formed at the reverse-cut end of the monocrystalline silicon rod 1 is larger. During forward cutting, the depth of the cut edge material is larger, and the side length of the square rod formed at the forward-cut end of the monocrystalline silicon rod 1 is smaller. For example, if the square root size of the forward cutting is a set square root size of 210mm, then the square root size of the reverse cutting must be greater than 210mm. A protruding step-like shape is formed at the reverse-cut end of the monocrystalline silicon rod 1 as the amplified redundancy 3. When the cutting tool exits after forward cutting, chipping 2 is generated. Chipping 2 exists on the protruding amplified redundancy 3 and does not extend into the interior of the single crystal silicon rod 1. In the subsequent grinding process, the amplified redundancy 3 containing chipping 2 can be ground away.

[0035] Optionally, the amplification dimension d of the amplification redundancy 3 is set to 0.5–1.5 mm, meaning the height of the protruding portion of the amplification redundancy 3 is 0.5–1.5 mm. The height of the protruding portion of the amplification redundancy 3 must be greater than the depth of the chipping 2 to ensure that the chipping 2 does not extend into the interior of the single-crystal silicon rod 1. For example, if the square root of the forward cut is a set open size of 210 mm, then the square root of the reverse cut can be set to 211 mm, and the height of the protruding portion of the amplification redundancy 3 is 0.5 mm, meaning the amplification dimension d is 0.5 mm; if the square root of the forward cut is a set open size of 210 mm, then the square root of the reverse cut can be set to 212 mm, and the height of the protruding portion of the amplification redundancy 3 is 1 mm, meaning the amplification dimension d is 1 mm; if the square root of the forward cut is a set open size of 210 mm, then the square root of the reverse cut can be set to 213 mm, and the height of the protruding portion of the amplification redundancy 3 is 1.5 mm, meaning the amplification dimension d is 1.5 mm. Preferably, the amplification dimension d of the amplification redundancy 3 is set to 1 mm.

[0036] Specifically, the cutting distance D1 in reverse cutting is greater than the maximum bow width of the cutting wire. During the cutting process using a cutting wire, bowing occurs due to the resistance of the monocrystalline silicon rod. The cutting distance refers to the travel distance of the cutting guide wheel. The bow of the cutting wire is the curved portion formed during the cutting process, which is usually dynamically changing. The bow width refers to the maximum lateral deviation between the actual cutting path and the theoretical path caused by the curvature of the cutting wire during the cutting process, i.e., the distance between the bottom of the bow's arc and the side of the cutting guide wheel that contacts the cutting wire. The bow width is related to material properties and process parameters such as cutting wire tension, cutting speed, material resistance, cutting wire diameter, and free span. The maximum bow width refers to the bow width under the cutting wire's stress limit. It is understandable that the maximum bow width varies depending on the equipment. To ensure the cutting length, the cutting distance must be greater than the cutting length and the maximum bow width. In this embodiment, the cutting distance D1 varies with the equipment, but it is always greater than the maximum bow width under the corresponding conditions. When the reverse cutting distance is less than or equal to the maximum width of the wire bow, the cutting wire cannot be guaranteed to fully enter the single crystal silicon rod 1 for cutting. Only when the reverse cutting distance D1 is greater than the maximum width of the wire bow can the cutting wire be guaranteed to fully enter the single crystal silicon rod 1 to truly achieve reverse cutting. The reverse cutting distance D1 should not be too large. The longer the length of the amplified redundancy 3 formed by the excessive reverse cutting distance, the more parts need to be worn in the subsequent grinding process. The edge skin cut off normally can be recycled, but the part ground off cannot be recycled. The larger the reverse cutting distance D1, the more unrecoverable parts there are, which will cause waste. For example, the maximum value of D1 can be twice the maximum width of the wire bow.

[0037] Specifically, such as Figure 5 As shown, forward cutting includes: entry cutting, middle cutting, exit cutting, return cutting, and re-exit cutting.

[0038] Forward cutting begins at a second cutting speed V2 with a cutting distance of D2. Mid-section cutting occurs at a third cutting speed V3 with a cutting distance of D3, and outward cutting occurs at a fourth cutting speed V4 with a cutting distance of D4. During both the initial and mid-section cutting, the cutting is performed according to a set square root dimension. The mid-section cutting guide wheel moves to the endpoint position of the reverse cutting guide wheel before exiting the cutting process. Due to line bowing, although the mid-section cutting guide wheel moves to the endpoint position of the reverse cutting guide wheel, the actual cutting length has not yet reached the reverse cutting endpoint, prematurely entering the outward cutting phase. To ensure that the outward cutting enters the reverse cutting seam, after the mid-section cutting, in the initial stage of the outward cutting, the cutting guide wheel drives the cutting line to gradually move outward toward the reverse cutting seam, enlarging the cutting size to create a bevel on the surface of the single-crystal silicon rod 1; that is, the stepped connection is the bevel. For example, the square root of the infeed cut and the middle cut is a set open size of 210mm, and the square root of the exit cut is the same as the square root of the reverse cut, which is 211mm; the square root of the infeed cut and the middle cut is a set square root of 210mm, and the square root of the exit cut is the same as the square root of the reverse cut, which is 212mm; the square root of the infeed cut and the middle cut is a set square root of 210mm, and the square root of the exit cut is the same as the square root of the reverse cut, which is 213mm. After enlarging the cut, the forward cut seam coincides with the reverse cut seam, and the cut line enters the reverse cut seam. When the cut line enters the reverse cut seam, it cuts through the monocrystalline silicon rod 1, generating a chipping 2 on the enlarged redundancy 3. The cut line continues to move along the reverse cut seam to the end of the monocrystalline silicon rod at a fourth cutting speed V4.

[0039] After the initial cutting is completed, a back cut is performed at the fifth cutting speed V5, with a back cut distance of D5. When the initial cutting is completed and the cutting wire moves to the end face of the single-crystal silicon rod 1 where it was reverse-cut, if the cutting is performed directly, due to wire bowing, the cutting wire will bounce back when it exits the single-crystal end face. Excessive bounce can cause wire breakage. Therefore, to buffer the wire bowing, when the detection device detects that the cutting wire has moved to the end face of the single-crystal silicon rod 1, the cutting wire is reverse-cut at the fifth cutting speed V5. That is, it cuts from the end of the single-crystal silicon rod 1 where it was reverse-cut along the cutting seam towards the other end, thus buffering the wire bowing and preventing the cutting wire from bouncing back excessively when it exits the single-crystal end face, which could cause wire breakage.

[0040] After the back cut is completed, the cutting wire is launched again at the sixth cutting speed V6, with a launch distance of D6. Because of the back cut, the wire bow is buffered, and there will be no significant rebound when the wire is launched again, thus reducing the risk of wire breakage.

[0041] Specifically, the first cutting speed V1, the fourth cutting speed V4, and the sixth cutting speed V6 are the same, i.e., V1 = V4 = V6. Using the same cutting speed at the reverse cutting end of the single crystal can minimize damage to the single crystal surface.

[0042] Specifically, the fifth cutting speed V5 is greater than the third cutting speed V3, and the third cutting speed V3 is greater than the second cutting speed V2, i.e., V2 < V3 < V5. During back-cutting, the higher fifth cutting speed V5 is more conducive to completing the bow wire buffering quickly within a shorter back-cutting distance. During forward cutting, to avoid damage to the end of the monocrystalline silicon rod 1, the second cutting speed V2 is lower during forward entry. When cutting to the middle of the monocrystalline silicon rod 1, all parameters remain stable, and the faster third cutting speed V3 is used for middle cutting to improve cutting efficiency. During reverse cutting, the cutting bow wire is cut in the opposite direction; to avoid causing equipment malfunctions, the first cutting speed V1 is lower than the second cutting speed V2.

[0043] Preferably, the ranges of V1, V4, and V6 are set to 20-200 mm / min. For example, V1, V4, and V6 can be set to 20 mm / min, 50 mm / min, 80 mm / min, 120 mm / min, 150 mm / min, and 200 mm / min. The range of V2 is set to 50-250 mm / min. For example, V2 can be set to 50 mm / min, 100 mm / min, 150 mm / min, 170 mm / min, 200 mm / min, and 250 mm / min. The range of V3 is set to 60-300 mm / min. For example, V3 can be set to 60 mm / min, 120 mm / min, 180 mm / min, 200 mm / min, 250 mm / min, and 300 mm / min. The range of V5 is set to 300-1000 mm / min, and exemplary V5 can be set to 300 mm / min, 500 mm / min, 600 mm / min, 750 mm / min, 900 mm / min, and 1000 mm / min.

[0044] Preferably, the cutting distance D1 for reverse cutting is set to 0 to 8% of the length of the monocrystalline silicon rod 1, the cutting distance D2 for forward cutting is set to 0 to 6% of the length of the monocrystalline silicon rod 1, the cutting distance D3 for middle cutting is set to 0 to 86% of the length of the monocrystalline silicon rod 1, the cutting distance D4 for exit cutting is set to 0 to 10% of the length of the monocrystalline silicon rod 1, the cutting distance D5 for back cutting is set to 0 to 3% of the length of the monocrystalline silicon rod 1, and the exit distance D6 for re-exit cutting is set to 0 to 6% of the length of the monocrystalline silicon rod 1.

[0045] Comparative example: A squaring process for a single-crystal silicon rod, with a diameter of 310mm for the round rod and a side length of 210mm for the square rod. The maximum width of the wire bow of the dicing line is 20mm.

[0046] S1: Load the monocrystalline silicon rod 1 onto the square cutting worktable, and use the positioning device to move the cutting guide wheel so that the cutting line is located at the head of the monocrystalline silicon rod 1 to position the forward cutting dimension.

[0047] S2: The cutting line makes a forward cut at the head of the monocrystalline silicon rod 1, cutting from the head along the length of the rod towards the tail. The cutting begins at a second cutting speed V2 = 50 mm / min, with a cutting distance of D2 = 60 mm. A third cutting speed V3 = 60 mm / min is used for the middle section cutting, with a cutting distance of D3 = 860 mm. Finally, a fourth cutting speed V4 = 20 mm / min is used for the exit cutting, until the edge skin is removed. Throughout the entire cutting process, the square root dimension remains constant at 210 mm.

[0048] After cutting one side of the monocrystalline silicon rod 1, the other sides are cut using the same steps. A chipping 2 forms on the tail end face of the monocrystalline silicon rod. Furthermore, due to wire bowing during cutting, the cutting wire bounces back significantly when exiting the tail end face of the monocrystalline rod, causing wire breakage.

[0049] Example 1: A squaring process for a single-crystal silicon rod. The diameter of the round rod is 310mm and the length is 1000mm. The round rod is squared, resulting in a square rod with a side length of 210mm. The maximum width of the wire bow of the dicing line is 20mm.

[0050] S1: Load the monocrystalline silicon rod 1 onto the square cutting worktable, use the positioning device to move the cutting guide wheel so that the cutting line is located at the tail of the monocrystalline silicon rod 1, and perform reverse cutting dimension positioning so that the side length of the square rod at the tail of the reverse-cut monocrystalline silicon rod is 211mm.

[0051] S2: The cutting line is used to make a large-scale cut along the length of the single-crystal silicon rod 1 from the tail end of the rod 1 towards the head at a first cutting speed V1 = 20 mm / min. The square root dimension after the reverse cutting is 211 mm, forming a 0.5 mm protrusion at the tail end of the single-crystal silicon rod 1. The cutting distance D1 is 80 mm, which is greater than the maximum width of the wire bow of the cutting line, to ensure complete cutting.

[0052] S3: Use a positioning device to move the cutting guide wheel so that the cutting line is located at the head of the monocrystalline silicon rod 1, and position the forward cutting dimension so that the side length of the square rod at the head and middle of the forward-cut monocrystalline silicon rod is 210mm.

[0053] S4: The cutting line is used for forward cutting at the head of the monocrystalline silicon rod 1, cutting along the length of the rod towards the tail. The entry cut is performed at a second cutting speed V2 = 50 mm / min, with a cutting distance of D2 = 60 mm. The middle cut is performed at a third cutting speed V3 = 60 mm / min, with a cutting distance of D3 = 860 mm. After the middle cut guide wheel moves to the end position of the cutting guide wheel used in the reverse cutting, the exit cut is performed. The exit cut is performed at a fourth cutting speed V4 = 20 mm / min, with a cutting distance of D4 = 100 mm. During the entry and middle cuts, normal cutting is performed with a square root dimension of 210 mm. After the middle cut is completed, in the initial stage of the exit cut, a larger cut is performed with a square root dimension of 211 mm used in the reverse cutting. When the cutting guide wheel for the central cut moves to the endpoint of the reverse cutting guide wheel, the cutting length has not yet reached the endpoint of the reverse cutting, and the cutting begins to exit. To ensure that the cutting wire can properly enter the reverse cutting seam during the exit cutting, in the initial stage of the exit cutting, the cutting guide wheel drives the cutting wire to gradually move outward toward the reverse cutting seam to enlarge the cutting by the square root of the reverse cutting dimension of 211mm, forming a bevel on the surface of the monocrystalline silicon rod 1, i.e., the stepped connection is the bevel. After the enlarged cutting is completed, the forward cutting seam coincides with the reverse cutting seam, and the cutting wire enters the reverse cutting seam, cutting through the monocrystalline silicon rod 1, causing chipping 2 on the enlarged redundancy 3 at the tail of the monocrystalline silicon rod 1. The cutting wire continues to move along the reverse cutting seam at the fourth cutting speed V4 to the tail of the monocrystalline silicon rod 1. After the cutting is completed, when the detection device detects that the cutting line has moved to the tail end face of the single crystal silicon rod 1, it performs a back cut at the fifth cutting speed V5 = 300 mm / min, with a back cut distance of D5 = 30 mm. After the back cut is completed, the cutting line is cut again at the sixth cutting speed V6 = 20 mm / min, with a cut distance of D6 = 60 mm.

[0054] After cutting one side of the monocrystalline silicon rod 1, the other sides are cut using the same steps. A stepped amplification redundancy is formed at the tail of the monocrystalline silicon rod 1, with an amplification size of 0.5 mm. After squaring, the chipping 2 formed at the tail of the monocrystalline silicon rod 1 has a depth of 0.3 mm and exists on the protruding amplification redundancy 3 at the tail of the monocrystalline silicon rod 1. Since the height of the protrusion of the amplification redundancy 3 is 0.5 mm, the chipping 2 will not extend into the interior of the squared silicon rod, ensuring the quality of the squaring. In the subsequent grinding process, the amplification redundancy 3 containing the chipping 2 can be ground away. Furthermore, due to the effective buffering of the wire bow during the back-cutting process, the cutting wire is not broken.

[0055] Example 2: A squaring process for a single-crystal silicon rod. The diameter of the round rod is 310mm and the length is 1000mm. The round rod is squared, resulting in a square rod with a side length of 210mm. The maximum width of the wire bow of the dicing line is 20mm.

[0056] S1: Load the monocrystalline silicon rod 1 onto the square cutting worktable, use the positioning device to move the cutting guide wheel so that the cutting line is located at the tail of the monocrystalline silicon rod 1, and perform reverse cutting dimension positioning so that the side length of the square rod at the tail of the reverse-cut monocrystalline silicon rod is 212mm.

[0057] S2: The cutting line is used to make a large-scale cut along the length of the single-crystal silicon rod 1 from the tail end of the rod 1 towards the head at a first cutting speed V1 = 80 mm / min. The square root of the cut is 212 mm, forming a 1 mm protrusion at the tail end of the rod 1. The cutting distance D1 is 80 mm, which is greater than the maximum width of the wire bow, to ensure complete penetration.

[0058] S3: Use a positioning device to move the cutting guide wheel so that the cutting line is located at the head of the monocrystalline silicon rod 1, and position the forward cutting dimension so that the side length of the square rod at the head and middle of the forward-cut monocrystalline silicon rod is 210mm.

[0059] S4: The cutting line makes a forward cut at the head of the monocrystalline silicon rod 1, cutting from the head along the length of the rod towards the tail. The entry cut is performed at a second cutting speed V2 = 100 mm / min, with a cutting distance of D2 = 60 mm. The middle cut is performed at a third cutting speed V3 = 200 mm / min, with a cutting distance of D3 = 860 mm. The exit cut is performed at a fourth cutting speed V4 = 80 mm / min, with a cutting distance of D4 = 100 mm. During the entry and middle cuts, normal cutting is performed with a square root of 210 mm. After the middle cut is completed, in the initial stage of the exit cut, a reverse cutting with a square root of 212 mm is used for enlarged cutting. When the cutting guide wheel for the middle cut moves to the end position of the reverse cutting guide wheel, the cutting length has not yet reached the end point of the reverse cutting, and the exit cut begins. To ensure proper entry into the reverse cutting slit during the initial cutting phase, the cutting guide wheel moves the cutting wire outwards towards the reverse cutting slit at the beginning of the cutting process, performing a magnified cut with a square root of 212mm. This creates a bevel on the surface of the monocrystalline silicon rod 1, specifically a stepped connection. After the magnified cut is completed, the forward cutting slit coincides with the reverse cutting slit, and the cutting wire enters the reverse cutting slit, cutting through the monocrystalline silicon rod 1. A chipping 2 occurs at the magnified redundancy 3 at the tail of the monocrystalline silicon rod 1. The cutting wire continues to move along the reverse cutting slit at a fourth cutting speed V4 until it reaches the tail of the monocrystalline silicon rod 1. After the cutting is completed, when the detection device detects that the cutting line has moved to the tail end face of the single crystal silicon rod 1, it performs a back cut at the fifth cutting speed V5 = 500 mm / min, with a back cut distance of D5 = 30 mm. After the back cut is completed, the cutting line is cut again at the sixth cutting speed V6 = 80 mm / min, with a cut distance of D6 = 60 mm.

[0060] After cutting one side of the monocrystalline silicon rod 1, the other sides are cut using the same steps. A stepped amplification redundancy is formed at the tail of the monocrystalline silicon rod 1, with an amplification size of 1mm. After squaring, the chipping 2 formed at the tail of the monocrystalline silicon rod 1 has a depth of 0.7mm and exists on the protruding amplification redundancy 3 at the tail of the monocrystalline silicon rod 1. Since the amplification redundancy 3 protrudes with a height of 1mm, the chipping 2 will not extend into the interior of the squared silicon rod, ensuring the quality of the squaring. In the subsequent grinding process, the amplification redundancy 3 containing chipping 2 can be ground away. Furthermore, due to the effective buffering of the wire bow during the back-cutting process, the cutting wire was not broken.

[0061] Example 3: A squaring process for a single-crystal silicon rod. The diameter of the round rod is 310mm and the length is 1000mm. The round rod is squared, resulting in a square rod with a side length of 210mm. The maximum width of the wire bow of the dicing line is 20mm.

[0062] S1: Load the monocrystalline silicon rod 1 onto the square cutting worktable, use the positioning device to move the cutting guide wheel so that the cutting line is located at the head of the monocrystalline silicon rod 1, and position the reverse cutting dimension so that the side length of the square rod at the head of the reverse-cut monocrystalline silicon rod is 213mm.

[0063] S2: The cutting line is used to make a large-scale cut along the length of the single-crystal silicon rod 1 from the head to the tail at a first cutting speed V1 = 100 mm / min. The square root dimension after the reverse cutting is 213 mm, forming a 1.5 mm protrusion of redundant 3 at the head of the single-crystal silicon rod 1. The cutting distance D1 is 80 mm, which is greater than the maximum width of the wire bow of the cutting line to ensure complete cutting.

[0064] S3: Use a positioning device to move the cutting guide wheel so that the cutting line is located at the tail of the monocrystalline silicon rod 1, and position the forward cutting dimension so that the side length of the square rod at the tail and middle of the forward-cut monocrystalline silicon rod is 210mm.

[0065] S4: The cutting line performs a forward cut at the tail of the monocrystalline silicon rod 1, cutting along the length of the rod towards the head. The entry cut is performed at a second cutting speed V2 = 200 mm / min, with a cutting distance of D2 = 60 mm. The middle cut is performed at a third cutting speed V3 = 250 mm / min, with a cutting distance of D3 = 860 mm. The exit cut is performed at a fourth cutting speed V4 = 100 mm / min, with a cutting distance of D4 = 100 mm. During the entry and middle cuts, normal cutting is performed with a square root dimension of 210 mm. After the middle cut is completed, in the initial stage of the exit cut, a reverse cutting square root dimension of 213 mm is used for enlarged cutting. When the cutting guide wheel for the middle cut moves to the end position of the reverse cutting guide wheel, the cutting length has not yet reached the end point of the reverse cutting, and the exit cut begins. To ensure proper entry into the reverse cutting slit during the initial cutting phase, the cutting guide wheel drives the cutting wire to gradually move outwards towards the reverse cutting slit, performing a magnified cut with a square root of 213mm. This creates a bevel on the surface of the monocrystalline silicon rod 1, specifically a stepped connection. After the magnified cut is complete, the forward cutting slit coincides with the reverse cutting slit, and the cutting wire enters the reverse cutting slit, cutting through the monocrystalline silicon rod 1. This results in chipping 2 on the magnified redundancy 3 at the head of the monocrystalline silicon rod 1. The cutting wire continues to move along the reverse cutting slit at a fourth cutting speed V4 until it reaches the head of the monocrystalline silicon rod 1. After the initial cutting is complete, when the detection device detects that the cutting wire has moved to the head end face of the monocrystalline silicon rod 1, a retraction cut is performed at a fifth cutting speed V5 = 900mm / min, with a retraction distance of D5 = 30mm. After the retraction, the cutting wire re-enters the market at a sixth cutting speed V6 = 100mm / min, with an exit distance of D6 = 60mm.

[0066] After cutting one side of the monocrystalline silicon rod 1, the other sides are cut using the same steps. A stepped amplification redundancy is formed at the head of the monocrystalline silicon rod 1, with an amplification size of 1.5mm. After squaring, the chipping 2 formed at the head of the monocrystalline silicon rod 1 has a depth of 1.2mm and exists on the protruding amplification redundancy 3 at the head of the monocrystalline silicon rod 1. Since the height of the protruding amplification redundancy 3 is 1.5mm, the chipping 2 will not extend into the interior of the squared silicon rod, ensuring the quality of the squaring. In the subsequent grinding process, the amplification redundancy 3 containing chipping 2 can be ground away. Furthermore, due to the effective buffering of the wire bow during the back-cutting process, the cutting wire was not broken.

[0067] The advantages and positive effects of this invention are:

[0068] 1. Perform reverse cutting first, then forward cutting, to shift the chipping at the end of the monocrystalline silicon rod towards the middle of the rod.

[0069] 2. During the reverse cutting process, a magnified redundancy is formed at the reverse cutting end of the monocrystalline silicon rod through amplification processing. During the forward cutting process, the cutting is first performed with a set square root size and then amplified cutting is performed to make the forward cutting seam coincide with the reverse cutting seam until the cutting is completed. This ensures that the chipping caused during the forward cutting appears on the magnified redundancy and does not extend into the interior of the monocrystalline silicon rod. The chipping can be removed by grinding away the magnified redundancy in the subsequent grinding process.

[0070] 3. It effectively reduces the chipping of the monocrystalline silicon rod end face during the squaring process, improves the squaring quality of the monocrystalline silicon rod, and ensures product quality.

[0071] 4. During the forward cutting process, the back cut is added to effectively buffer the cutting wire bow and reduce the risk of wire breakage when the blade exits.

[0072] The embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. It should be noted that implementations not illustrated or described in the drawings or the main text of the specification are forms known to those skilled in the art and have not been described in detail. Furthermore, the definitions of the various components described above are not limited to the specific structures, shapes, or methods mentioned in the embodiments, and those skilled in the art can easily modify or substitute them.

[0073] It should also be noted that, in the specific embodiments of this disclosure, unless explicitly indicated or stated otherwise, the numerical parameters in this specification and the appended claims are approximate values ​​and can be changed according to the desired characteristics obtained from the content of this disclosure. Specifically, all numbers used in the specification and claims to indicate dimensions, range conditions, etc., of the composition should be understood to be modified by the term "about" in all cases. Generally, this means that there may be variations of ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, and ±0.5% in some embodiments.

Claims

1. A process for squaring a single crystal silicon ingot, characterized by, Includes the following steps: One end of the single-crystal silicon rod is cut in the reverse direction along the axial direction; The other end of the single-crystal silicon rod is cut along the axial direction until the edge skin is completely removed.

2. The squaring process for a single-crystal silicon rod according to claim 1, characterized in that: During the reverse cutting process, cutting is performed at a first cutting speed V1. The maximum edge thickness of the reverse cut is less than the maximum edge thickness of the forward cut. An amplified redundancy is formed at one end of the single crystal silicon rod where the reverse cut is performed. The cutting distance of the reverse cut is D1.

3. The squaring process for a single-crystal silicon rod according to claim 2, characterized in that: The amplification size of the amplification redundancy is set to 0.5–1.5 mm.

4. The squaring process for a single-crystal silicon rod according to claim 3, characterized in that: The cutting distance D1 of the reverse cut is greater than the maximum width of the bow of the cutting line.

5. The squaring process for a single-crystal silicon rod according to any one of claims 2-4, characterized in that: The forward cutting includes the following steps: The cutting is performed at a second cutting speed V2, and the cutting distance of the cutting is D2. The middle section is cut at a third cutting speed V3, and the cutting distance of the middle section is D3; The cutting is performed at a fourth cutting speed V4, and the cutting distance of the cutting is D4.

6. The squaring process for a single-crystal silicon rod according to claim 5, characterized in that: During the initial cutting and middle cutting processes, cutting is performed with a set square root dimension. During the exit cutting process, enlarged cutting is performed so that the cutting line enters the cutting line seam of the reverse cutting. The enlarged cutting forms a slope on the surface of the single crystal silicon rod.

7. The squaring process for a single-crystal silicon rod according to claim 6, characterized in that: After the cutting is completed, a back cut is performed at the fifth cutting speed V5, with a back cut distance of D5.

8. The squaring process for a single-crystal silicon rod according to claim 7, characterized in that: After completing the back cut, the blade is extended again at the sixth cutting speed V6, with an extension distance of D6.

9. The squaring process for a single-crystal silicon rod according to claim 8, characterized in that: The first cutting speed V1, the fourth cutting speed V4, and the sixth cutting speed V6 are the same. The fifth cutting speed V5 is greater than the third cutting speed V3. The third cutting speed V3 is greater than the second cutting speed V2. The second cutting speed V2 is greater than the first cutting speed V1.

10. The squaring process for a single-crystal silicon rod according to claim 8 or 9, characterized in that: The reverse cutting distance D1 is set to 0-8% of the length of the single crystal silicon rod, the infeed cutting distance D2 is set to 0-6% of the length of the single crystal silicon rod, the middle cutting distance D3 is set to 0-86% of the length of the single crystal silicon rod, the outfeed cutting distance D4 is set to 0-10% of the length of the single crystal silicon rod, the backcutting distance D5 is set to 0-3% of the length of the single crystal silicon rod, and the second outfeed distance D6 is set to 0-6% of the length of the single crystal silicon rod.

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