Silicon single crystal rod cutting device and cutting method

Abstract

The invention discloses a silicon single crystal rod cut-off device and a cut-off method, and aims to solve the problem of edge breakage caused by stress concentration, rigid contact and poor diameter adaptability of a crystal rod in an existing fixing mode. The method comprises the following steps: arranging a plurality of cambered-surface PVC (Polyvinyl Chloride) support tables with curvature radiuses matched with those of a silicon single crystal rod at intervals along the axial direction, coating a composite binder on the inner surfaces of the cambered-surface PVC support tables, erecting the silicon rod, and curing to form an elastic buffer layer; then the whole body is transferred to a cutting machine, and fixed-length cutting is conducted on the suspended section through a diamond wire; and after cutting is completed, the assembly is fed into an oven at the temperature of 80 DEG C to be subjected to heat preservation for 5-20 min, and clean separation of the cambered surface PVC and the silicon rod is achieved by means of the thermal response decoupling characteristic of the composite binder. The elastic buffer layer not only has excellent interface buffer and stress dispersion capabilities to eliminate the edge breakage phenomenon, but also has proper peel strength and initial hardness, integrates clamping stability and demolding convenience, and remarkably improves the product appearance quality and the production efficiency.

Description

Technical Field

[0001] This invention relates to the field of single-crystal silicon rod cutting technology, specifically to a single-crystal silicon rod cutting device and cutting method. Background Technology

[0002] In the semiconductor materials manufacturing industry, cutting crystal rods (single-crystal silicon rods) to a certain length (typically 30-50cm) is a crucial step in the production process. This process is essential to ensure the smooth operation of subsequent processing steps. Currently, the industry commonly uses V-grooves combined with wooden wedge plugs to fix the crystal rods (see figure) to achieve stable cutting. However, as the size of the crystal rods, especially their diameter, increases, this traditional method has gradually revealed a series of problems.

[0003] First, when processing large crystal ingots with a diameter ≥350mm, the weight of the ingot itself generates a large torque on the suspended portion of the ingot during the cutting process. This causes stress concentration at the cutting contact point, resulting in a high chipping rate, as high as 15%-22%. This not only wastes raw materials but also reduces the yield of cut products.

[0004] Secondly, the traditional V-groove support structure (see figure) has linear support characteristics, providing only two-point contact support, which cannot effectively distribute the load applied to the crystal rod, resulting in excessive local stress. Furthermore, the wooden wedge-shaped plug used for fixing has rigid contact with the crystal rod, lacking necessary buffering capacity, further exacerbating the concentration of local stress. At the same time, since crystal rods of different diameters require different support methods and clamping forces, the existing V-groove design is difficult to adapt to the needs of various crystal rod specifications, limiting its application range.

[0005] The root cause of the above problems lies in the fact that the design of the existing fixing scheme fails to effectively address issues such as stress concentration, rigid contact, and poor adaptability to crystal rods of different diameters. These problems combined make the crystal rods highly susceptible to edge chipping during the cutting process, severely impacting product quality and production efficiency. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention discloses a single crystal silicon rod cutting device and cutting method, which can solve or at least alleviate one or more of the above-mentioned problems or other problems existing in the prior art.

[0007] This invention discloses a method for cutting a single-crystal silicon rod, comprising the following steps:

[0008] S1. In the material preparation area, multiple support platforms are arranged at intervals along the axial direction of their curved PVC surfaces, and the radius of curvature of the curved PVC surfaces is adapted to the diameter of the single crystal silicon rod to be cut.

[0009] S2. Apply composite adhesive to the inner surface of each curved PVC surface;

[0010] S3. The monocrystalline silicon rod is placed inside the curved PVC of multiple support platforms; the composite adhesive is cured between the monocrystalline silicon rod and the curved PVC to form an elastic buffer layer;

[0011] S4. Transfer the loaded support platforms and monocrystalline silicon rods to the monocrystalline silicon cutting machine, and sequentially position and install the support platforms in the corresponding bases of the linear reciprocating sliding track system in the feeding area, so that the support platforms are fitted into the grooves of the bases.

[0012] S5. Multiple curved platforms and the monocrystalline silicon rod are slid into the cutting area of ​​the monocrystalline silicon cutting machine. The monocrystalline silicon cutting machine uses a high-speed reciprocating diamond wire as a flexible saw blade to first cut the head and tail of the monocrystalline silicon rod, and then cuts the cylindrical monocrystalline silicon rod suspended between the curved platforms and clamped in the axial direction to a fixed length.

[0013] S6. Transfer the fixed-length monocrystalline silicon rod supported on the curved PVC to an oven. Heat the oven to 80℃ and keep it at that temperature for 5-20 minutes to demold the curved PVC from the monocrystalline silicon rod, thus obtaining a fixed-length monocrystalline silicon rod without any appearance defects.

[0014] Preferably, in step S2, the composite binder comprises, by weight, 35-45 parts modified sodium silicate solution, 25-35 parts nano alumina sol, 10-20 parts aluminum dihydrogen phosphate powder, 8-12 parts aqueous polyurethane dispersion, 2-3 parts graphene-modified silica and 1-2 parts thermosensitive microcapsule phase change material.

[0015] Preferably, the preparation process of the composite adhesive is as follows:

[0016] S201. Add modified sodium silicate solution to a container, and under stirring conditions, slowly add nano alumina sol to the modified sodium silicate solution to mix it thoroughly and form a homogeneous and stable inorganic phase base liquid.

[0017] S202. Under continuous stirring, graphene-modified silica powder is uniformly added to the above inorganic base liquid.

[0018] S203. Continue stirring and slowly add the aqueous polyurethane dispersion drop by drop;

[0019] S204. Add aluminum dihydrogen phosphate powder evenly and stir thoroughly. Aluminum dihydrogen phosphate powder acts as an inorganic curing agent and reacts with modified sodium silicate solution to produce gel instantly.

[0020] S205. Add temperature-sensitive microcapsule phase change material under low-speed stirring conditions;

[0021] S206. After all components are mixed, let it stand for a period of time to mature, so as to obtain a homogeneous and stable composite adhesive.

[0022] Preferably, in step S201, the stirring conditions are low-speed stirring, with a stirring speed of 200-400 rpm.

[0023] Preferably, in step S202, the stirring conditions are medium-speed stirring, with a stirring speed of 500-800 rpm.

[0024] Preferably, in step S205, the core material of the thermosensitive microcapsule phase change material is γ-butyrolactone and δ-valerolactone.

[0025] Preferably, in step S206, the mixture is left to stand for 5-20 minutes to mature.

[0026] The present invention also discloses a single-crystal silicon rod cutting device, comprising:

[0027] The machine body has a feeding area and a cutting area;

[0028] A linear reciprocating sliding track system, which is installed in the machine body and runs through the feeding area and the cutting area; and

[0029] Multiple curved platforms on a linear reciprocating sliding track system with sliding fit.

[0030] Preferably, the arc-shaped platform includes a base and a support platform. The base is slidably fitted on a linear reciprocating sliding track system, and the base is provided with a groove adapted to the support platform. The support platform includes a bearing seat and an arc-shaped PVC surface disposed on the bearing seat.

[0031] Preferably, the curved PVC is available in various specifications, and the radius of curvature of the curved PVC in various specifications covers 300-500mm.

[0032] The present invention has the following beneficial effects:

[0033] This technical solution effectively alleviates the stress concentration problem caused by traditional rigid clamping by introducing an elastic buffer layer formed by a composite adhesive between the monocrystalline silicon rod and the curved PVC support platform. The buffer layer has the flexible bonding ability to adapt to crystal rods of different diameters, good initial bonding strength and controllable demolding properties triggered by 80°C heat, which significantly eliminates edge chipping defects during the cutting process, while achieving non-destructive and efficient demolding, greatly improving the surface quality and production yield of fixed-length cut silicon rods. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of this disclosure, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0035] Figure 1 This is a schematic diagram of the structure of a single-crystal silicon cutting machine in one embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of a single-crystal silicon rod mounted on an arc-shaped stage according to an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of the arc-shaped platform in one embodiment of the present invention;

[0038] Figure 4 These are the external morphological images of the single-crystal silicon rods after being cut in Examples 1-5 of the present invention;

[0039] Figure 5 These are images showing the morphological appearance of the single-crystal silicon rods after being cut, as shown in Comparative Examples 1-3 of this invention.

[0040] Figure label:

[0041] 101-Main body, 102-Feeding area, 103-Cutting area, 104-Linear reciprocating sliding track system, 105-Curved platform, 106-Base, 107-Groove, 108-Bearing seat, 109-Curved PVC, 110-Monocrystalline silicon rod, 111-Elastic buffer layer. Detailed Implementation

[0042] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments designed in the embodiments and comparative examples of this invention are commonly used reagents and instruments, all of which are commercially available. Unless otherwise specified, the experimental methods used in the embodiments and comparative examples are conventional methods.

[0043] To overcome the shortcomings of existing technologies and improve the reliability and yield of the crystal rod cutting process, this invention develops a method for cutting single-crystal silicon rods. This method possesses excellent stress dispersion capabilities and can adapt to crystal rods of different diameters. Particularly effective for cutting large-sized (φ300mm-φ500mm) crystal rods, it reduces localized stress concentration caused by rigid contact, thus meeting the requirements of modern, efficient, and high-quality crystal rod cutting processes.

[0044] Monocrystalline silicon rods are cut using a monocrystalline silicon cutting device, such as... Figures 1 to 3 As shown, the monocrystalline silicon cutting device uses a monocrystalline silicon cutting machine. The machine body 101 of the monocrystalline silicon cutting machine adopts a linear reciprocating sliding track system 104 that runs through the feeding area 102 and the cutting area 103. Multiple detachable curved platforms 105 are slidably fitted on the system. The curved platform 105 includes a base 106 and a support platform. The base 105 is slidably fitted on the linear reciprocating sliding track system 104. The base 105 has a groove that matches the support platform. The support platform includes a bearing seat 108 and a curved PVC 109 set on the bearing seat 108. The curved PVC 109 has various specifications, with a curvature radius covering 300-500mm. Among them, the curved PVC is made of high-hardness PVC (Shore hardness ≥85D). During operation, multiple support platforms are first arranged at intervals along the axial direction of their curved PVC surfaces in the preparation area. The spacing is determined according to the length of the monocrystalline silicon rod 110 to be cut. Next, a composite adhesive is applied to the inner side of each curved PVC surface, and then the monocrystalline silicon rod 110 is placed on the curved PVC surfaces of the multiple support platforms. The composite adhesive forms an elastic buffer layer 111 between the curved PVC surfaces and the monocrystalline silicon rod in a short time. Subsequently, the multiple support platforms and the monocrystalline silicon rod as a whole are transferred from the preparation area to the monocrystalline silicon cutting machine, and the multiple support platforms are correspondingly matched on the multiple bases 106 of the linear reciprocating sliding track system 104. Finally, the multiple curved platforms 105 and the monocrystalline silicon rod 110 as a whole are slid into the cutting area 103 of the monocrystalline silicon cutting machine. The monocrystalline silicon cutting machine uses a high-speed reciprocating diamond wire as a flexible saw blade to cut the cylindrical monocrystalline silicon rod 110, which is suspended between the curved platforms 105 and clamped axially, to a fixed length.

[0045] In this technical solution, an arc-shaped platform is used to replace the V-groove sliding platform of the traditional monocrystalline silicon cutting machine. The locking of the arc-shaped platform in the cutting area of ​​the monocrystalline silicon cutting machine and the locking of the original V-groove sliding platform in the cutting area use the same technology and the locking is existing technology. The other components of the monocrystalline silicon cutting machine and their connection methods and working principles are existing technologies, and will not be described in detail here.

[0046] The preparation method of modified sodium silicate solution mainly includes four core steps: raw material pretreatment, modulus adjustment, chemical modification, and post-treatment. First, the industrial sodium silicate solution is diluted to the target solid content (usually 35%-40%, 35% in this invention) and filtered to remove insoluble impurities. Then, the SiO2 / Na2O molar ratio (modulus) of the system is precisely adjusted by adding sodium hydroxide or activated silica to stabilize it within the target range of 2.6-3.2, thereby controlling its reactivity and curing characteristics. Next, under conditions of 50-80℃ and continuous stirring, a silane coupling agent (KH-550) is slowly introduced into the system to allow it to undergo grafting or complexation reactions with silicate ions, thereby introducing organic functional groups onto the inorganic framework, significantly improving compatibility with polymers and the toughness of the final cured product. Finally, the reaction solution is cooled, the pH is adjusted to between 10-11, and after aging and filtration, a homogeneous and stable modified sodium silicate solution is obtained. This method achieves directional optimization of silicate solutions from composition to structure through controllable modulus design and chemical modification, providing key basic components for high-performance composite adhesives.

[0047] Among them, the thermosensitive microcapsule phase change material has a shell material of polyurethane and a core material of γ-butyrolactone and δ-valerolactone (γ-butyrolactone:δ-valerolactone = 1:1~3:1 are all acceptable), with a particle size of 30-50μm.

[0048] The preparation of graphene-modified silica is mainly achieved through a sol-gel process combining chemical grafting and self-assembly, with the specific steps as follows:

[0049] (1) Preparation of graphene oxide (GO) dispersion

[0050] Weigh 1.5 kg of commercial graphene oxide powder and add it (C / O ratio approximately 2.0–2.5) to deionized water at a concentration of 1.5 mg / mL. Treat the solution with ultrasound at 200–400 W for 30–60 minutes under ice bath conditions to obtain a monolayer or few-layer, homogeneous, and stable GO aqueous suspension. During this process, the abundant carboxyl (–COOH), hydroxyl (–OH), and epoxy groups on the surface of the GO sheets can serve as active sites for subsequent reactions.

[0051] (2) In-situ sol-gel coating of silica

[0052] At pH 9–10 (adjusted with ammonia) and 25 ± 2°C, tetraethyl orthosilicate (TEOS) was slowly added dropwise to the above-mentioned GO aqueous suspension at a mass ratio of 1:2, while continuously stirring at 500–800 rpm. The reaction system was then aged at room temperature for 12–24 hours to allow TEOS to hydrolyze and condense on the GO surface, generating in situ amorphous silica nanoparticles with a particle size of 10–50 nm, forming a GO@SiO2 core-shell or anchored structure.

[0053] (3) Silane coupling agent bridging and strengthening interface

[0054] To further enhance the interfacial bonding between graphene and silica, 3-glycidoxypropyltrimethoxysilane (KH-560) was introduced as a covalent molecular bridge. KH-560 was added at 10 wt% of the GO mass, and the reaction was carried out at 60°C under nitrogen protection for 2–4 hours. Under these conditions, the methoxy group at one end of KH-560 hydrolyzed and condensed with the silanol groups on the silica surface to form a stable Si–O–Si bond, while the epoxy group at the other end underwent a ring-opening reaction with the carboxyl or hydroxyl groups on the graphene oxide surface, constructing a robust covalent connection. This process formed a strong and tough covalent interface between graphene and silica, significantly improving the thermal stability and compatibility of the hybrid structure.

[0055] (4) Post-processing and product collection

[0056] After the reaction was complete, the product was centrifuged at 8000–10000 rpm for 15 minutes and washed alternately with deionized water and anhydrous ethanol 3–5 times to remove unreacted substances. It was then dried in a vacuum oven at 60°C for 12 hours to obtain GO@SiO2 hybrid powder.

[0057] Among them are nano alumina sol (Jinghuo, JHAL-15), aluminum dihydrogen phosphate powder (Hongjia), and waterborne polyurethane dispersion (Feimiao Chemical, PUD FS-6A).

[0058] All parts of raw materials used in the following examples and comparative examples are by weight.

[0059] Example 1

[0060] The present invention provides a method for cutting a single-crystal silicon rod, comprising the following steps:

[0061] S1. In the material preparation area, multiple support platforms are arranged at intervals along the axial direction of their curved PVC surfaces. The radius of curvature of the curved PVC surfaces is adapted to the diameter of the monocrystalline silicon rod to be cut. The spacing is determined according to the length of the monocrystalline silicon rod to be cut, so that the curved PVC surfaces correspond to the middle of the cut monocrystalline silicon rod.

[0062] S2. Apply composite adhesive to the inner surface of each curved PVC surface;

[0063] S3. The monocrystalline silicon rod is placed inside the curved PVC of multiple support platforms; the composite adhesive can connect the monocrystalline silicon rod to the curved PVC in a short time and form an elastic buffer layer between the monocrystalline silicon rod and the curved PVC.

[0064] S4. Transfer the loaded support platforms and monocrystalline silicon rods to the monocrystalline silicon cutting machine, and sequentially position and install the support platforms in the corresponding bases of the linear reciprocating sliding track system in the feeding area, so that the support platforms are fitted into the grooves of the bases.

[0065] S5. Multiple curved platforms and the monocrystalline silicon rod are slid into the cutting area of ​​the monocrystalline silicon cutting machine. The monocrystalline silicon cutting machine uses a high-speed reciprocating diamond wire as a flexible saw blade to first cut the head and tail of the monocrystalline silicon rod, and then cuts the cylindrical monocrystalline silicon rod suspended between the curved platforms and clamped in the axial direction to a fixed length.

[0066] S6. Transfer the fixed-length monocrystalline silicon rod supported on the curved PVC to an oven. Heat the oven to 80℃ and keep it at that temperature for 5-20 minutes to demold the curved PVC from the monocrystalline silicon rod, thus obtaining a fixed-length monocrystalline silicon rod without any appearance defects.

[0067] In step S2, the composite binder comprises 35 parts modified sodium silicate solution, 25 parts nano alumina sol, 10 parts aluminum dihydrogen phosphate powder, 8 parts aqueous polyurethane dispersion, 2 parts graphene-modified silica and 1 part thermosensitive microcapsule phase change material.

[0068] The preparation process of the composite adhesive is as follows:

[0069] S201. Add modified sodium silicate solution to a container, and slowly add nano-alumina sol to the modified sodium silicate solution under low-speed (200-400 rpm) stirring conditions to ensure thorough mixing and form a homogeneous and stable inorganic phase base liquid. In this step, the modified sodium silicate solution forms a continuous inorganic network skeleton, providing the main adhesive matrix and high-temperature resistance. Nano-alumina can act as a reinforcing point for the inorganic network, improving density, initial adhesion, and final strength by filling gaps.

[0070] S202. Under continuous low-speed stirring, graphene-modified silica powder is uniformly added to the above-mentioned inorganic base liquid. On the one hand, graphene-modified silica can improve the dispersion effect and ensure that the nano-sized alumina does not agglomerate, so as to promote the nano-sized alumina to achieve the best reinforcement effect. On the other hand, graphene-modified silica can guide the exfoliation in a directional manner. The layered structure formed by graphene-modified silica has a large number of easily separable parallel interfaces preset in the elastic buffer layer.

[0071] S203. Adjust the stirring speed to medium speed (500-800 rpm), and then slowly add the water-based polyurethane dispersion drop by drop. This allows the inorganic network skeleton and the organic polymer to initially achieve interweaving and compatibility at the microscopic level, forming an adhesive film that can absorb stress and prevent brittleness.

[0072] S204. Add aluminum dihydrogen phosphate powder evenly and stir thoroughly. Aluminum dihydrogen phosphate powder, as a key inorganic curing agent, reacts with the silicate system to instantly produce gel, thus providing rapid curing capability.

[0073] S205. Adjust the stirring speed to low and add the thermosensitive microcapsule phase change material. Low-speed stirring aims to avoid shear forces damaging the integrity of the thermosensitive microcapsule phase change material, ensuring its thermal management function is preserved. When the thermosensitive microcapsule phase change material is heated to 80℃, it releases lactone compounds, chemically decoupling the interface between the elastic buffer layer and the monocrystalline silicon rod, significantly reducing the bonding force to facilitate demolding of the curved PVC from the monocrystalline silicon rod. The core substances of the thermosensitive microcapsule phase change material are γ-butyrolactone and δ-valerolactone.

[0074] S206. After all components are mixed, let stand for 5-20 minutes to mature, so as to obtain a homogeneous and stable composite adhesive.

[0075] During oven-heated demolding, the thermosensitive microcapsule phase change material initially remains stably dispersed within an elastic buffer layer. The wall material of the thermosensitive microcapsule phase change material is in a glassy or crystalline state, possessing sufficient mechanical strength to withstand shear forces during mixing and internal stresses during curing, ensuring no leakage of the core material. When the temperature reaches 80℃, the molecular chain movement of the thermosensitive microcapsule phase change material wall material intensifies, resulting in a glass transition and a sharp decrease in its mechanical strength, transforming it from a robust "micro-container" into a soft, porous, or even ruptured "micro-sponge." Essentially, the thermosensitive microcapsule phase change material is a pre-programmed "thermally triggered chemical switch" within the bulk adhesive material. Upon receiving an 80℃ temperature signal, it automatically executes a "release-migration-weakening" process. Through molecular-level actions such as chemical decoupling, interfacial plasticization, and lubrication, it fundamentally reduces interfacial bonding forces, thereby synergizing with the macroscopic layered peeling design to achieve controllable, clean, and low-damage demolding.

[0076] When the wall material of the temperature-sensitive microcapsule phase change material fails, the encapsulated lactone compounds are rapidly released. Because these compounds are liquid and have a small molecular weight, they immediately migrate and penetrate through the micropores within the adhesive layer, driven by capillary action and external heating, to the interface between the adhesive layer and the monocrystalline silicon rod / curved PVC. The main adhesive of the elastic buffer layer is a silicate system, whose adhesive nature involves forming strong Si-O-Si covalent bonds or strong hydrogen bonds with the adhered material (such as the silanol groups -Si-OH on the surface of the monocrystalline silicon rod). Under heating and with the presence of trace amounts of moisture, the lactone compounds undergo ring-opening hydrolysis to generate corresponding hydroxy acids. These generated hydroxy acid molecules have active groups (-COOH and -OH) at both ends, which competitively bind to the silanol groups on the monocrystalline silicon surface, forming a monomolecular isolation layer. This isolation layer disrupts the original strong chemical bonds between the silicate network and the silicon surface, achieving "chemical decoupling" and significantly reducing the interfacial energy.

[0077] Furthermore, after the wall material of the temperature-sensitive microcapsule phase change material fails, the released lactone compounds form a molecular-level isolation film at the interface between PVC and the elastic buffer layer. This hydrophobic liquid film not only blocks the van der Waals forces and mechanical interlocking between silicate and PVC surface, but also weakens the interfacial binding energy through its lubricating properties, thereby achieving controllable physical interface separation without relying on the breaking of chemical bonds.

[0078] Example 2

[0079] The preparation process and apparatus of this embodiment are the same as those of Embodiment 1. The difference is that the composite binder includes 45 parts of modified sodium silicate solution, 35 parts of nano alumina sol, 20 parts of aluminum dihydrogen phosphate powder, 12 parts of aqueous polyurethane dispersion, 3 parts of graphene-modified silica and 2 parts of thermosensitive microcapsule phase change material.

[0080] Example 3

[0081] The preparation process and apparatus of this embodiment are the same as those of Embodiment 1. The difference is that the composite binder includes 40 parts of modified sodium silicate solution, 30 parts of nano alumina sol, 15 parts of aluminum dihydrogen phosphate powder, 10 parts of aqueous polyurethane dispersion, 3 parts of graphene-modified silica and 2 parts of thermosensitive microcapsule phase change material.

[0082] Example 4

[0083] The preparation process and apparatus of this embodiment are the same as those of Embodiment 1. The difference is that the composite binder includes 38 parts of modified sodium silicate solution, 32 parts of nano alumina sol, 18 parts of aluminum dihydrogen phosphate powder, 12 parts of aqueous polyurethane dispersion, 2 parts of graphene-modified silica and 1 part of thermosensitive microcapsule phase change material.

[0084] Example 5

[0085] The preparation process and apparatus of this embodiment are the same as those of Embodiment 1. The difference is that the composite binder includes 43 parts of modified sodium silicate solution, 27 parts of nano alumina sol, 13 parts of aluminum dihydrogen phosphate powder, 9 parts of aqueous polyurethane dispersion, 2 parts of graphene-modified silica and 2 parts of thermosensitive microcapsule phase change material.

[0086] Comparative Example 1

[0087] The preparation process and apparatus of this embodiment are the same as those of Embodiment 1. The difference is that a traditional V-groove stage is used to support the single crystal silicon rod, and a wooden wedge plug is used to fix the single crystal silicon rod on the V-groove stage.

[0088] Comparative Example 2

[0089] The preparation process and apparatus of this embodiment are the same as those of Embodiment 1. The difference is that the composite binder includes 60 parts of modified sodium silicate solution, 40 parts of nano alumina sol, 30 parts of aluminum dihydrogen phosphate powder, 20 parts of aqueous polyurethane dispersion, 6 parts of graphene-modified silica and 5 parts of thermosensitive microcapsule phase change material.

[0090] Comparative Example 3

[0091] The composite binder comprises 20 parts modified sodium silicate solution, 15 parts nano alumina sol, 5 parts aluminum dihydrogen phosphate powder, 5 parts aqueous polyurethane dispersion, 0.5 parts graphene-modified silica, and 0.5 parts thermosensitive microcapsule phase change material.

[0092] In Examples 1-5 and Comparative Examples 1-3, a φ400mm single-crystal silicon rod, a 10Kg support platform, and a standing time of 10min in step S206 are used as examples for illustration. The low-speed stirring is 200rpm, and the medium-speed stirring is 600rpm.

[0093] Performance testing

[0094] Testing standards:

[0095] (1) After cutting, the single crystal silicon rod is directly observed to see if there are any appearance defects or chipped corners;

[0096] (2) Curing time of composite adhesive: Apply composite adhesive to the inner side of the arc PVC of each support platform, and place the monocrystalline silicon rod in the arc PVC of multiple support platforms. Let it stand for 5 minutes, lift the monocrystalline silicon rod, and observe whether the support platform falls off.

[0097] (3) Demolding: Transfer the fixed-length monocrystalline silicon rod supported on the curved PVC to the oven, heat the oven to 80°C and keep it warm for 10 minutes; then take it out, and the operator puts on heat-resistant gloves to observe whether the curved PVC can be easily separated from the monocrystalline silicon rod by hand, and observe whether the elastic buffer layer can be easily peeled off from the monocrystalline silicon rod or the curved PVC like a "sticky note".

[0098] (4) Peel strength: ASTM D903 standard was adopted; the composite adhesive was applied to the substrate according to the standard, and after curing, it was moved to the oven and heated to 80°C for 10 minutes to obtain the test sample.

[0099] (5) Curing hardness: ASTM E384 standard is adopted; the composite adhesive is applied to the substrate according to the standard, and left to stand for 5 minutes to obtain the test sample.

[0100] Test results: The performance test results are shown in Table 1.

[0101] Table 1

[0102]

[0103] The data in Table 1 show that the elastic buffer layers prepared in Examples 1-5 of this invention have good curing properties, allowing for easy demolding. Their peel strength and curing hardness are higher than those in Comparative Examples 2-3, and the elastic buffer layer eliminates edge chipping. Figure 4 As shown, this demonstrates that the combined effect of the various raw materials in this invention achieves a synergistic effect, and the absence of any one of them weakens the effect.

[0104] From Table 1 and Figure 5 As can be seen, when Comparative Example 1 uses a traditional V-groove stage combined with a wooden wedge to support the monocrystalline silicon rod, due to the weight of the monocrystalline silicon rod itself in the cut area and the rigid point support formed by the wooden wedge, a large torque will be generated in the suspended part of the monocrystalline silicon rod during the cutting process. This causes stress concentration at the cutting contact point, resulting in edge chipping.

[0105] Comparing Example 1 and Comparative Example 2, it is evident that as the amounts of each component increase—that is, both the organic and inorganic phases of the composite binder increase—excessive inorganic phase leads to rapid curing and shrinkage stress, while excessive organic phase also generates shrinkage stress during the curing and film-forming process. The simultaneous rapid formation and competition for space between the organic and inorganic phases, along with their mismatched expansion coefficients and shrinkage directions, generates enormous internal stress, far exceeding the material's bearing capacity. This results in cracks or micro-cracks appearing during or immediately after curing. The elastic buffer layer fails to provide effective flexible support for the monocrystalline silicon rod, primarily due to insufficient interfacial adhesion or uneven thickness of the elastic buffer layer material, making it difficult to effectively absorb and disperse the localized impact and vibration stress generated by diamond wire saw cutting during the severing process. Consequently, the monocrystalline silicon rod, under highly brittle conditions, bears concentrated loads, especially prone to stress abrupt changes at the edges, making it highly susceptible to corner chipping (or edge chipping) during severing. Figure 5 As shown, this severely affects the geometric accuracy and surface integrity of the cut silicon rod. When separating the curved PVC and the single-crystal silicon rod, the elastic buffer layer itself is torn apart, leaving a damaged and discontinuous elastic buffer layer on both the curved PVC and the single-crystal silicon rod. This is because during the curing process, the competitive reaction between the organic and inorganic phase systems may encapsulate gas or produce microscopic phase separation, forming microbubbles, cracks, and other defects. These defects and cracks become stress concentration points. When attempting to "tear" them off, the cracks propagate rapidly, causing the entire adhesive layer to break. At the same time, the huge internal stress generated by the organic and inorganic phase systems causes the elastic buffer layer to crack and tear from its weakest point when subjected to slight external force, making the entire elastic buffer layer extremely fragile.

[0106] Comparing Example 1 and Comparative Example 3, it can be seen that as the content of each component in the composite adhesive decreases simultaneously, although the relative ratio of the organic phase to the inorganic phase may remain unchanged, its absolute content is insufficient to support the formation of an effective network structure. During the curing process, the inorganic phase content is too low to construct a continuous and stable rigid three-dimensional skeleton, resulting in insufficient overall material modulus. Simultaneously, insufficient organic phase content makes it difficult to form a continuous and dense adhesive film, weakening the effective wetting and anchoring effect on the interface between the monocrystalline silicon rod and the curved PVC surface. The lack of synergy between these two factors means that the elastic buffer layer lacks both the necessary mechanical support and sufficient adhesive properties, failing to effectively buffer and homogenize the dynamic load during the cutting process. Ultimately, this induces microcrack propagation in stress concentration areas, leading to edge or corner chipping when the monocrystalline silicon rod is cut. Figure 5As shown, when separating the curved PVC and the monocrystalline silicon rod, both the curved PVC and the monocrystalline silicon rod will have some elastic buffer layer attached, which is difficult to clean. This is because there is too little of both organic and inorganic phases, which will make the elastic buffer layer brittle or powdery. During separation, due to the effect of the organic phase, both the curved PVC and the monocrystalline silicon rod will have some brittle or powdery elastic buffer layer attached. Moreover, the organic and inorganic phases are not fully cross-linked, making it difficult to cleanly remove the brittle or powdery elastic buffer layer.

[0107] In summary, the composite adhesive of this invention comprises 35-45 parts modified sodium silicate solution, 25-35 parts nano-alumina sol, 10-20 parts aluminum dihydrogen phosphate powder, 8-12 parts aqueous polyurethane dispersion, 2-3 parts graphene-modified silica, and 1-2 parts thermosensitive microcapsule phase change material. By optimizing the proportions of each component, a stable multiphase composite system was successfully prepared. This system can achieve full interweaving and compatibility between inorganic and organic phases, forming a stable elastic buffer interface layer between the curved PVC and the single-crystal silicon rod. After curing, it has a suitable initial support hardness (25-45 HV after 5 min curing) and can be triggered by heating at 80°C to release the decoupling medium from the microcapsules, reducing the interfacial peel strength to 0.5-2.5 N / cm, thereby achieving controllable and convenient separation of the curved PVC, the single-crystal silicon rod, and the elastic buffer layer.

[0108] The above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit it. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure, and they should all be covered within the scope of the claims and specification of this disclosure.

Claims

1. A method of cutting a single crystal silicon ingot, characterized by, The method comprises the following steps: S1, arranging a plurality of support tables along the axial direction of the arc surface PVC in the preparation area, the curvature radius of the arc surface PVC is matched with the diameter of the single crystal silicon rod to be cut; S2, applying a composite adhesive on the inner surface of each arc surface PVC; S3, erecting the single crystal silicon rod in the arc surface PVC of the plurality of support tables; the composite adhesive is cured between the single crystal silicon rod and the arc surface PVC to form an elastic buffer layer; S4, transferring the plurality of support tables and the single crystal silicon rod after loading to the single crystal silicon cutting machine, and positioning the plurality of support tables in the corresponding seats of the linear reciprocating sliding rail system in the loading area in sequence, so that the support tables are embedded in the grooves of the seats; S5, sliding the plurality of arc surface tables and the single crystal silicon rod into the cutting area of the single crystal silicon cutting machine, and cutting the head and tail of the single crystal silicon rod with the high-speed reciprocating diamond wire as a flexible saw blade, and then cutting the cylindrical single crystal silicon rod suspended between the arc surface tables to a fixed length; S6, transferring the fixed-length single crystal silicon rod carried on the arc surface PVC to an oven, heating the oven to 80℃, and keeping warm for 5-20min, so that the arc surface PVC and the single crystal silicon rod are demolded to obtain a fixed-length single crystal silicon rod without appearance defects.

2. The single crystal silicon rod cutting method according to claim 1, wherein: in the step S2, the composite adhesive comprises, by weight, 35-45 parts of modified sodium silicate solution, 25-35 parts of nano alumina sol, 10-20 parts of aluminum dihydrogen phosphate powder, 8-12 parts of aqueous polyurethane dispersion, 2-3 parts of graphene modified silicon dioxide, and 1-2 parts of temperature-sensitive microcapsule phase change material.

3. The single crystal silicon rod cutting method according to claim 2, wherein: the preparation process of the composite adhesive is as follows: S201, adding modified sodium silicate solution in a container, and slowly adding nano alumina sol into the modified sodium silicate solution under stirring conditions to fully mix and form a uniform and stable inorganic phase base liquid; S202, uniformly adding graphene modified silicon dioxide powder into the above inorganic base liquid under continuous stirring; S203, continue to maintain stirring, and slowly add aqueous polyurethane dispersion drop by drop; S204, uniformly add aluminum dihydrogen phosphate powder and fully stir, and the aluminum dihydrogen phosphate powder as an inorganic curing agent reacts with the modified sodium silicate solution to produce gel instantaneously; S205, add temperature-sensitive microcapsule phase change material under low-speed stirring conditions; S206, after all components are mixed, stand for a period of time for curing to obtain a homogeneous and stable composite adhesive.

4. The single crystal silicon rod cutting method according to claim 4, wherein: in the step S201, the stirring condition is low-speed stirring, and the stirring speed is 200-400 rpm.

5. The single crystal silicon rod cutting method according to claim 4, wherein: in the step S202, the stirring condition is medium-speed stirring, and the stirring speed is 500-800 rpm.

6. The single crystal silicon rod cutting method according to claim 4, wherein: ​ ​ ​ ​ The core material of the temperature-sensitive microcapsule phase change material in the step S205 is γ-butyrolactone and δ-valerolactone.

7. The single crystal silicon rod cutting method according to claim 4, wherein: In the step S206, the aging is performed for 5-20 minutes.

8. A single crystal silicon rod cutting apparatus characterized by comprising: Comprise: The machine body has a loading area and a cutting area; The linear reciprocating sliding track system is arranged in the machine body and penetrates through the loading area and the cutting area; And The arc surface loading platform is slidably fitted on the linear reciprocating sliding track system.

9. The single crystal silicon rod cutting method according to claim 8, wherein: The arc surface loading platform comprises a base and a support platform, the base is slidably fitted on the linear reciprocating sliding track system, and the base is provided with a groove matched with the support platform; the support platform comprises a bearing seat and an arc surface PVC arranged on the bearing seat.

10. The single crystal silicon rod cutting method according to claim 8, wherein: The arc surface PVC has multiple specifications, and the curvature radius of the arc surface PVC of the multiple specifications covers 300-500 mm.

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